Technical Memorandum #1: Inventory Review and System

The Municipality of Thames Centre

Technical Memorandum #1: Inventory Review and System Characteristics

Prepared by:

AECOM Canada Ltd. 105 Commerce Valley Drive West, 7th Floor Markham, ON L3T 7W3 Canada T: 905.886.7022 F: 905.886.9494 www.aecom.com

Date: January, 2020

Project #: 60586191

February 10, 2020 Page 1 of 320

Distribution List

# Hard Copies PDF Required Association / Company Name

✓ The Municipality of Thames Centre ✓ AECOM Canada Ltd.

Revision History

Revision # Date Details Name Position

0 Oct 8, 2018 Initial Draft Khalid Kaddoura Asset Management Consultant 1 Oct. 16, 2018 Technical Review Rabia Mady Technical Lead 2 Oct. 19, 2018 Draft Submission Michele Samuels Senior Asset Management Consultant 3 Jun 06, 2019 Final Submission Khalid Kaddoura

Michele Samuels Asset Management Consultant Senior Asset Management Consultant


AECOM The Municipality of Thames Centre Technical Memorandum #1: Inventory Review and System Characteristics

TM1_2020-01-30_Inventory Review & System Characteristics_60586191_V3.Docx

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Authors

Report Prepared By: Khalid Kaddoura, PhD, PMP

Report Verified By: for Rabia Mady (no longer employed by AECOM)

Report Approved By: Michele Samuels, M.Eng., P.Eng., MBA



Table of Contents page

1. Introduction ....................................................................................... 1

1.1 Project Background ................................................................................................. 1

1.2 Objectives for Technical Memorandum #1 .............................................................. 2

2. Best Practices and Industry Review ................................................. 3

2.1 Risk-based Assessment .......................................................................................... 3

2.1.1 AWWA J100:10 Risk and Resilience Management of Water and Wastewater Systems ................................................................................................................. 3

2.1.2 ISO31000:2009 Risk Management – Principles and guidelines .............................. 4

2.1.3 Implementing Quality Management: A Guide for Ontario’s Drinking Water Systems ................................................................................................................. 5

2.1.4 Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/ Risk Management Approach ............................................................. 5

3. Deterioration and Failure Modes ...................................................... 6

3.1 Structural Failure Drivers ......................................................................................... 6

3.1.1 Inability to Resist Applied Loading .......................................................................... 6

3.1.2 Material Deterioration Modes.................................................................................. 7 3.1.2.1 Ferrous Metal Pipes (Cast Iron & Ductile Iron) .................................................. 7 3.1.2.2 Cementitious Pipes (Asbestos Cement) ........................................................... 8 3.1.2.3 Thermoplastic Pipes (Polyvinyl Chloride and High Density Polyethylene) ......... 9 3.1.2.4 Copper Pipes (CU) ......................................................................................... 10

3.2 Hydraulic Failure Drivers ....................................................................................... 10

4. Summary of the Current Inventory of Watermains ........................ 11

4.1 Age Profile ............................................................................................................. 11

4.2 Material Profile ...................................................................................................... 12

4.3 Diameter Profile..................................................................................................... 13

4.4 Municipality Staff Experience ................................................................................ 14

5. Conclusions and Recommendations.............................................. 15

5.1 Conclusions ........................................................................................................... 15

5.2 Recommendations ................................................................................................ 15

6. References ....................................................................................... 17



List of Figures Figure 2-1: AWWA J100:10 Seven-Step RAMCAP Process extracted from AWWA (2010, p.xvii) ..................... 4 Figure 2-2: ISO31000 Risk Management Process adapted from ISO31000 (2009, p.14) .................................. 4 Figure 3-1: Pressurized Pipeline Failure Modes ............................................................................................... 6 Figure 4-1: Length of Watermain Installed by Year ......................................................................................... 11 Figure 4-2: Watermain Material Types by Length Percentage ......................................................................... 12 Figure 4-3: Length of Watermain by Material Class and Decade..................................................................... 13 Figure 4-4: Watermain Diameter Pie chart...................................................................................................... 13 Figure 4-5: Watermain Diameter and Material Class ...................................................................................... 14

List of Tables Table 3-1: PVC Design Standard Changes and Factors of Safety ................................................................... 9 Table 3-2: HDPE Design Standard Changes and Factors of Safety ............................................................... 10 Table 4-1: Watermain Material Types by Length (m) ..................................................................................... 12 Table 4-2: Municipality Staff Interviews – Key Highlights ............................................................................... 14

Appendices Appendix A. Minutes of Staff Interview


TM1_2020-01-30_Inventory Review & System Characteristics_60586191_V3.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 59.6 km of watermain infrastructure (1.8 km of watermains are privately owned) to supply water and provide management services to a population of 13,191 residents (Statistics Canada, 2017). The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2 (Statistics Canada, 2017). Unlike wastewater and/or stormwater collection systems, pressurized watermains are often operationally and cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing them in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF), and can present significant risks on the event of an unexpected failure. Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess pressurized watermains. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition, assess failure risk, and estimate residual design life in watermains’ infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing the inspections to minimize the risk exposure while optimizing budgetary allowances. On this basis, pressurized watermains can be managed effectively, through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of the assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based state of good repair program to: 1. Prioritize and assess watermains

2. Analyze pipe life cycle

3. Provide an annual funding forecast

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with procedures and tools to prioritize watermains for inspections including the means to assess existing pipe material inventory and prioritize these inspected watermains for renewal in the short-, mid-, and long-term. The primary objective of this study is to develop a maintenance renewal schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-objectives including, but not limited to, the following: 1. Reviewing inventory data;



2. Identifying failure modes and distress indicators;

3. Developing a consequence of failure model including prioritizing pipes for assessment;

4. Matching suitable technologies, and planning a pipeline condition assessment trial for a critical watermain previously identified by the risk model;

5. Interpreting inspection findings to estimate the likelihood of failure (LoF);

6. Defining the level of service; and

7. Building a comprehensive risk-based decision matrix tree for pipe renewal.

1.2 Objectives for Technical Memorandum #1 To implement an effective infrastructure management strategy, one should first review the existing management program and systems and compare them with the overall organizational objectives and best management practices. The gaps between the existing situation and the desired objectives of the organization form the basis of the overall risk management approach. The tasks involved in this review include: 1. Characterization of the existing inventory;

2. Identification and usage of industry best management practices applicable for relevant asset and material types; and

3. Determination of the effectiveness of existing management policies and procedures, and recommendations for areas needing improvement.

Therefore, the goals of this Technical Memorandum (TM) #1 are as follows:

1. Summary of Watermain Inventory To summarize the outcomes of a review of existing water linear asset information;

2. Risk-management Best Practices To provide a review of industry best practices related to pressurized pipe’s risk management.

This includes a summary of key best practices, as well as the identification of gaps in the existing practices of the Municipality, and the exploration of some methods for improvement;

3. Literature Review on Material Types To provide a literature and industry review for some material types in the water linear asset

inventory of the Municipality, for the purpose of establishing the material characteristics, deficiencies, failure modes and drivers, and deterioration patterns. Consideration will be given to the specific design era practices for certain materials of any given vintage. The review will identify common characteristics and applied loads that can lead to deterioration and/or premature failure of the linear asset type. AECOM has a comprehensive inventory of all industry standard design practices for each material type in the inventory and has utilized this to highlight any increased risk associated with the materials from different eras; and

4. Analysis of Watermain System Information To analyze information compiled about the system of the Municipality alongside the best

practices’ review and the deterioration and failure modes to demonstrate how the key findings relate to the existing system.



2. Best Practices and Industry Review

2.1 Risk-based Assessment Risk-based planning and decision making is the foundation of modern tactical linear infrastructure asset management. Infrastructure related risk exposure is an assessment based on the probability and consequence of asset failure. It is used to drive the selection and prioritization of related actions that are based on organizational risk tolerance thresholds and sustainable funding levels. Generally, the overall risk of distinct assets is best measured by applying Equation [1] [Water Environment Research Foundation (WERF), 2010]: 𝑅𝑖𝑠𝑘 𝐸𝑥𝑝𝑜𝑠𝑢𝑟𝑒 = 𝑃𝑟𝑜𝑏𝑎𝑏𝑖𝑙𝑖𝑡𝑦 𝑜𝑓 𝐹𝑎𝑖𝑙𝑢𝑟𝑒 (𝑃𝑜𝐹)𝑥 𝐶𝑜𝑛𝑠𝑒𝑞𝑢𝑒𝑛𝑐𝑒 𝑜𝑓 𝐹𝑎𝑖𝑙𝑢𝑟𝑒 (𝐶𝑜𝐹) [1] The abovementioned equation considers two parameters in the computation of the Risk Exposure, which are the Probability or Likelihood of Failure (PoF or LoF) and the Consequence of Failure (CoF). The PoF parameter, for pressurized pipelines, is heavily linked with the ability of the watermain to sustain its designed limit states before failure. The lower the designed Factor of Safety (FOS), the more the asset is prone to breakage. Meanwhile, the CoF is associated with the direct and indirect costs of losses of an asset. Direct costs could include damage to private or public property, or impacts to public health and safety or the environment. Indirect costs could relate to contractual violations, customer dissatisfaction, and fines or penalties. (Muhlbauer, 2004). In recent years, infrastructure related risks have increasingly become the subject of discussion among organizations responsible for physical infrastructure. A risk-based assessment and management strategy should be well-structured and systematic. Several methodologies have been developed to assess and manage risks. The risk assessment process described in each is similar. However, minor differences are present, and some sources modify the basic risk equation in terms of assessing resiliency separately from failure consequences. The literature review examined the following methods:

1. The American Water Works Association (AWWA) J100:10 – Risk and Resilience Management of Water and Wastewater Systems (RAMCAP) (AWWA, 2010)

2. The International Organization for Standardization (ISO) 31000:2009 Risk Management – Principles and guidelines ( ISO31000, 2009)

3. Implementing Quality Management (Ministry of Environment, 2007)

4. The Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/Risk Management Approach (Canadian Water and Wastewater Association, 2005)

2.1.1 AWWA J100:10 Risk and Resilience Management of Water and Wastewater Systems

The RAMCAP was developed as a result of the attacks of September 11, 2001, by the American Society of Mechanical Engineers (ASME). The framework is specific to water and wastewater systems, which considers a wide range of failures. These failures include man-made threats, hazards (earthquake, tornados, etc.) and dependency hazards (interruptions of supply chains or proximity to dangerous sites). For the purposes of this study, man-made threats and hazards (tornadoes, floods, etc.) are assumed to be extremely unlikely and so are not considered in the LoF parameter.



The RAMCAP approach breaks down LoF into two elements: vulnerability analysis and threat analysis. Threat analysis estimates the likelihood that a particular threat occurs. Vulnerability analysis predicts the likelihood that each specific threat, given it occurs, will have the consequences predicted. Thus, risk is calculated as the product of consequences, vulnerability, and threat. Figure 2-1 outlines the RAMCAP’s risk assessment approach.

Figure 2-1: AWWA J100:10 Seven-Step RAMCAP Process extracted from AWWA (2010, p.xvii)

2.1.2 ISO31000:2009 Risk Management – Principles and guidelines

The ISO 31000:2009 Risk Management standard provides generic guidelines to risk assessment and management, which is not specific to an industry or sector. The role of risk management within an organization is emphasized, as well as the need for communication, monitoring and review throughout the risk management process. The standard defines risk evaluation as “the process of comparing the results of risk analysis with the risk criteria to determine whether the risk and/or its magnitude is acceptable or tolerable” ( ISO31000, 2009, p. 6). The key steps in evaluating risk within this framework are shown in Figure 2-2.

Figure 2-2: ISO31000 Risk Management Process adapted from ISO31000 (2009, p.14)

Risk assessment

Establishing the context

Risk identification

Risk analysis

Risk evaluation

Risk treatment

Mon

itori

ng a

nd re

view

Com

mun

icat

ion

and

cons

ulta

tion



2.1.3 Implementing Quality Management: A Guide for Ontario’s Drinking Water Systems

This guide pertains to the implementation of the Ontario Drinking Water Quality Management Standard (DWQMS). It includes elements of the ISO 9001 (regarding quality management systems) and the Hazard Analysis and Critical Control Point (HACCP) standard. It should be noted that this guide is geared towards assessing the risk associated with water quality hazards rather than the risk associated with water infrastructure. The ‘Plan and Do’ methodology published in this guidance outlines the requirement for a risk management process that:

1. Identifies potential hazardous events and the associated hazards; 2. Assesses risks associated with the occurrence of hazardous events; 3. Ranks the hazardous events according to the associated risks; 4. Identifies control measures to address the potential hazards and hazardous events; 5. Identifies critical control points; 6. Identifies a method to verify at least once a year, the accuracy of information and the validity of the

assumptions used in the risk assessment; 7. Ensures that a risk assessment is conducted at least once every thirty-six months; and 8. Considers equipment reliability and redundancy.

The method for scoring risk described in this guide uses detectability as an optional parameter along with the LoF and the CoF. For each asset, a score from 1 to 5 is assigned to each parameter, and then they are summed (rather than multiplied) to calculate an overall risk score.

2.1.4 Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/ Risk Management Approach

This approach to risk assessment, which is developed by the Canadian Water and Wastewater Association (2005), is similar in many ways to Implementing Quality Management: A Guide for Ontario’s Drinking Water Systems. However, the suggested method of assessing the risk associated with each asset varies between the two guides. Where the Implementing Quality Management sums parameter values to determine an overall score, the Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/ Risk Management Approach uses the product of the CoF and LoF to find an overall risk score. This document also makes reference to the relative scoring of assets. It suggests that an accelerated scale (e.g., 1,3,5,7, 9 instead of 1,2,3,4, 5), an exponential, or a log rating scale be used when evaluating risks to give greater emphasis to the high LoF and CoF events.



3. Deterioration and Failure Modes

Risk assessment, along with subsequent treatment and/or mitigation options for water pipeline infrastructure, should be based on an understanding of the failure mode of pressurized pipe during its service-life. It should be noted that while there is an inherent relationship between assets within the overall system (e.g., pumping stations and related equipment) and the linear assets, this study will focus on the assessment and management of the likelihood and consequence of linear asset’s failures only. Typical pressurized pipeline failure modes are outlined as follows (Notes: Structural Failure: Due to material degradation and their inability to resist applied loads; and Hydraulic Failure: Due to a loss of capacity or their inability to meet quality objectives. Figure 3-1):

Notes: Structural Failure: Due to material degradation and their inability to resist applied loads; and

Hydraulic Failure: Due to a loss of capacity or their inability to meet quality objectives.

Figure 3-1: Pressurized Pipeline Failure Modes

3.1 Structural Failure Drivers Structural failures within pressure pipelines are typically driven by the deterioration of the pipe material and by the resultant inability of the pipe to resist the applied loads during normal operating conditions. The key drivers of structural failure are further examined within the following sections.

3.1.1 Inability to Resist Applied Loading

Pipelines must be designed and specified to resist various applied loads, such as:

◼ The external loading − Vehicular live loads; and − Soil and surface structure dead loads.

◼ The internal pressure of transported liquids ◼ Bending and deflection from soil movement

The changes within the surrounding environment or within the operating conditions of the pipeline, such that the previous loads exceed those estimated during the original design, can contribute to failure. When the pipe wall thickness or strength is compromised due to material degradation, the ability to resist these loads is also reduced.

Failure Mode

Structural Failure

Hydraulic Failure



3.1.2 Material Deterioration Modes

To understand the causes of pipeline failure, it is important to consider the primary factors that are responsible for deterioration. This will be influenced by many factors including the type of surrounding soil, operating pressures within the pipe, method of construction, groundwater conditions, surface or overburden loading, and the interactions of these upon the deterioration of the material type. These factors should all be considered to carry out a complete assessment of LoF. The primary watermain material types used in the Municipality of Thames Centre are divided into four main groups:

Ferrous Metal Cementitious Non-Ferrous Metal Thermoplastic Ductile Iron (DI) Cast Iron (CI)

Asbestos Cement (AC)

Copper (CU) Polyvinyl Chloride (PVC) High Density Polyethylene

(HDPE), etc Deterioration drivers for CI, DI, and AC material types are linked to exposure to several environmental factors. Conversely, PVC pipelines are not affected by most environmental factors but can be significantly affected by the magnitude of applied internal and external stresses. HDPE is similar to PVC except that it may be sensitive to environmental factors such as exposure to deoxidizing agents (chlorine). Most pressurized pipe designs are typically based on hoop (circumferential) stress analysis, while the ultimate failure mode is often due to flexural stress or simple perforation of the pipe wall due to corrosion. The FOS against failure for hoop stress is generally constant through different pipe diameters. The flexural FOS against failure increases with increasing diameters as does the time to fully perforate a pipe wall, as hoop stress design uses a common diameter to thickness ratio. The following sections identify typical deterioration factors for each pipe material type currently in service within the Municipality’s inventory.

3.1.2.1 Ferrous Metal Pipes (Cast Iron & Ductile Iron)

The primary contributing mechanism for failure of ferrous materials is extensively related to corrosion. Corrosion can occur in many different forms in terms of either generalized or localized corrosion processes, with localized corrosion being far more prevalent than the generalized corrosion processes. Corrosion is not a diameter sensitive issue; it is a material loss issue and eventually affects all ferrous pipes, regardless of size. In CI and DI pipes, the ultimate failure mode is often flexural or purely related to wall thickness; therefore, failures of smaller pipeline diameters appear earlier during their service lives. The corrosion process may stop over time or shift within a system due to the impact of more global corrosion processes. In heavily graphitized pipes, the most common failure initiator is the ground movement on a weakened conduit, which usually generates a flexural failure rather than hoop stress failure. The design life of ferrous pipes is well documented to increase with increasing diameter, primarily due to the thicker pipes walls associated with larger diameters being less sensitive to material loss through corrosion or the much increased FOS associated with the pipe in flexure in larger diameters. Methods of assessing condition on ferrous pipes typically involve an examination of corrosion and the associated environmental factors. External corrosion is promoted due to the corrosivity of soils that impacts ferrous pipes. Cathodic protection can have a profound impact on the future corrosion rates in CI and DI systems, an effect observed by many researchers and well developed in some analytical models (Kleiner & Rajani, 2003). Where coatings and cathodic protection systems are used in a comprehensive maintenance work program, the effect of external environment is less pronounced in a main’s failure history.



Design and Manufacturing Standards

The first manufactured CI pipe was known as “pit” cast gray iron. The pipe was designed with greater wall thickness than required for internal pressure and external loading which could have led to potential inconsistencies in wall thickness. However, the performance of the pipe was well received within the industry in spite of it not having any kind of internal or external corrosion protection. Pit cast iron pipes were manufactured in the 19th century and installed until the 1940s. Spun-cast iron pipe followed in the late 1920s and were extensively installed until the 1970s. The inconsistencies in the wall thickness were reduced to a large extent resulting in thinner walls. DI pipes were introduced in the 1950s and replaced spun-cast iron by the late 1960s. DI pipe is characterized by thinner wall with uniformed thickness. Understanding micro-corrosion cells is significant to assessing the common corrosion that occurs in DI and CI pipes, as dissimilar metals can lead to atypical potential using soil (earth) as an electrolyte. Between the late 1930s and mid 1950s, lead services usage was replaced by the use of copper services which, in low resistivity soils, promoted high external corrosion. In the absence of cathodic protection, it could be assumed that DI designed for the same installation condition will not provide the equivalent life of CI in the same corrosive environment. The first AWWA standard C151/A21.51 was issued in 1965 and revised in 1971, 1976, 1981, and 1986. During these periods and advancements, the required wall thicknesses generally reduced. For example, in 1908, a 36” pipe (at 150 psi) had a wall thickness of 1.58” but by 1991, the thickness was reduced to 0.38”. In 1991, the standard was changed to a pressure class system and the thickness class was no longer standard.

3.1.2.2 Cementitious Pipes (Asbestos Cement)

Material deterioration is the most common driving process for AC pipe failure. The failure will occur more commonly due to flexure (longitudinal beam) as opposed to hoop (circumferential) stress. The effective design-life increases with increasing diameters. Previous studies have identified several common soil and water conditions that can cause concrete products to deteriorate, as indicated below:

◼ Soft waters, which leach calcium (lime and soluble silicates) from cement; ◼ Soluble sulphates; and ◼ Acidic conditions;

− Organic acids, as occur in marshlands, bogs and peaty soils; − Inorganic acids, as occur in mine waters, or are generated in cinder fills or through the oxidation

of sulphides; − Dissolved carbon dioxide; and − Soils having hydrogen ion exchange ability, which act to remove the calcium from the Portland

cement structure and replace it with the hydrogen acid radical. Methods of assessing the condition of AC pipes typically involve an examination of the most predominant of the previously mentioned environmental factors.

Design and Manufacturing Standards

Before 1975, the manufacturing standards in North America to all AC pipe sizes were based on AWWA C400. However, after 1975/77, different manufacturing standards were used for several diameter ranges. Pipe diameters between 4” and 16” were based on the AWWA C400 manufacturing standard; on the other hand, pipe diameters between 18” and 42” were based on the AWWA C402 manufacturing standard. Similar to the manufacturing standards, the design standards changed by era. Prior to 1975, the design standards in North America to all AC pipe sizes were based on AWWA C401, which was referred to as the AWWA standard practice H2 (1964). After



1975/77, pipe diameters between 4” and 16” were based on the AWWA C401 design standard, while pipe diameters between 18” and 42” were based on the AWWA C403 designed standard. The techniques used for evaluating internal and external loads of AC pipes are provided in the AWWA C401 and C403. The first standard for AC pipe was C400-53T, which was established in 1953. In 1964, C400-64 was introduced, which included silica as a constituent and outlined a standard test method for determining the free lime content. The free lime content has a direct relation to pipe corrosion resistance; pipes with high percentage of free lime are more vulnerable to corrosion due to acid and sulphate soils. In 1975, this was further revised to C400-75 which incorporated the selection of pipes for different working environments.

3.1.2.3 Thermoplastic Pipes (Polyvinyl Chloride and High Density Polyethylene)

PVC is a thermoplastic material that is typically driven to failure due to applied stresses and not due to material loss or degradation. PVC has three reasonably well-understood; yet, independent failure modes:

1. Resistance to slow-crack growth in response to long term sustained pressure; 2. Resistance to bursting in response to short-term overpressure; and 3. Resistance to fatigue in response to exposure to large cyclic pressure variations.

The first of the above failure modes can be examined through a balance of desktop analysis and opportunistic sampling and assessment. The second would become apparent in the examination of the failure records. The third, fatigue, is commonly caused in pressurized pipe applications as large cyclic pressure variations due to pumps stopping and starting. When PVC fails, it is subject to rapid-crack growth as a failure mode, which can result in large losses of fluid. HDPE, another thermoplastic pipe material, is similar to PVC and subject to the same three independent failure modes. However, its resistance to fatigue is much higher than PVC and is not subject to rapid-crack growth. As a result, failures are typically less catastrophic when they occur.

Design Standards

Over the years, there have been a number of adjustments to the design standards of PVC pressurized pipes, which provide an indication of the designed FOS, and therefore, the tolerance to applied loads. Table 3-1 provides an overview of the design standard adjustments and relevant dates. The table outlines that pressurized pipes having pipe diameters less than or equal to 300 mm, which were constructed prior to 1975, and pipes with diameters greater than 300 mm installed prior to 1988 had FOS of 2.0 and the lowest quality assurance standard of the pipes, when compared to other contemporary design standards. In addition, PVC pressurized pipes with diameters less than or equal to 300 mm installed between 1975 and 1997 had FOS of 2.5. Pipes with diameters greater than 300 mm installed between 1988 and 2007 had FOS of 2.0, and 2.5 for short-term overpressure.

Table 3-1: PVC Design Standard Changes and Factors of Safety

PVC ≤ 300 mm Diameter PVC > 300 mm Diameter Date Comment Date Comment

Pre-1975 ASTM Series Pipe D2241 FOS of 2.0, and 2.0 for short-term overpressure; Lowest Quality

Assurance Standard

Pre-1988 ASTM Series Pipe D2241 FOS of 2.0, and 2.0 for short-term overpressure; Lowest Quality Assurance Standard

1975 AWWA C900; FOS of 2.5 and 2.5 for short-term overpressure

1988 AWWA C905; FOS 2.0 and 2.5 for short-term overpressure; high quality assurance standard.

1997 AWWA C900; FOS of 2.0; occasional surge introduced to selection criteria

2007 AWWA C905; FOS 2.0 and 2.0 for short term overpressure; occasional surge introduced to selection criteria



Variations in the HDPE design standards are shown in Table 3-2. After 1982, the specifications of the HDPE improved and design standards were recognized. The major advancements were in providing a material that is resistant to slow-crack propagation and capable of withstanding higher hydrostatic design stresses.

Table 3-2: HDPE Design Standard Changes and Factors of Safety

Date Comment Pre 1982 No recognized Hydrostatic Design Basis for HDPE

1982 to 2006 Phasing in of PE3608 resin which has a standard design code. This class of resin has a density classification of three, a slow-crack growth resistance with the standard classification of six, and a 800 psi hydrostatic design stress

2007 to date Phasing in of PE4710 resin, which has a higher density classification of four (i.e., an increased tensile strength and stiffness), a higher slow crack growth resistance with the standard classification of seven and a 1,000 psi hydrostatic design stress

3.1.2.4 Copper Pipes (CU)

Copper is the most widely used material for plumbing systems due to its ease of installation. However, copper was used as service connections until it was replaced by other materials such as lead. Copper pipes are vulnerable to internal corrosion that can develop due to hard and/or soft water causing pitting corrosion and ultimately pinhole leaks or external corrosion due to aggressive soils. The Municipality’s pipe inventory included a minor quantity of Copper (15.7 m). Therefore, no detailed discussion is included in this report describing this type of material.

3.2 Hydraulic Failure Drivers Water networks are designed to provide water demand at an acceptable pressure for consumers and in emergency cases (i.e., for firefighting). Any variations in these levels would negatively impact consumption. Water network components are subjected to deterioration due to aging (Rajani & Kleiner, 2004). Increased degradation in these elements will have a direct impact on the PoF. Hydraulic failure of pressurized watermains would generally result in a high consequence to those responsible for operating the system. The hydraulic failure in pressurized system is defined as the inability of the pipe to meet flow and capacity requirements. Besides ageing, as a global factor, some other influencing factors can contribute to hydraulic failure as follows:

◼ Loss of conveyance capacity due to internal corrosion or surface roughness; ◼ Loss in conveyance capacity due to the inability of the pipe to handle air movement effectively; and/or ◼ Loss of pumping capacity due to deteriorating pump performance.



4. Summary of the Current Inventory of Watermains

The water network in the Municipality of Thames Centre is composed of approximately 60 km of buried watermains. From the total length, about 2 km is privately owned. The following discussion summarizes the information related to age, material type, and diameter as identified from the Municipality’s GIS data.

4.1 Age Profile The age of an asset in the context of its design standard may play a role in a preliminary screening of its condition due to the general assumption that an older asset will have a greater likelihood of failure than a newer one. Additional complexity is introduced as different eras of the same material type can experience subtle differences in potential failure in a counterintuitive manner. Improvements to the manufacturing process of CI, and its evolution to DI, for example, resulted in the manufacturing of thinner pipe walls that, due to corrosion, failed in shorter time periods than earlier versions of the same material with thicker pipe walls. Subtle changes in many material standards such as in AC and PVC pipes have also resulted in lower safety factors being used in later years of construction when using the same material types. In the absence of more detail, the age of an asset can be a screening tool to estimate its condition. In fact, in some studies, the age alone was considered in the calculation of the LoF in buried pipelines (Halfawy, Dridi, & Bajer, 2008). Within materials of unique characteristics (for example, in instances when the change in standard or manufacturing processes can be clarified), age is definitely a useful proxy. Within the Municipality of Thames Centre, watermains were installed between 1956 and 2017. Figure 4-1 illustrates the total length of watermains that were installed in a specific period. According to the figure and from the total length (57.8 km) of the watermains, 11.7 km (20.2%) of the watermains were installed between 1955 and 1985. Approximately, 36.7 km (63.5%) of the watermains were constructed between 1985 and 2010, and 9.4 km (16.2%) of the watermains were laid between 2010 and 2017.

Figure 4-1: Length of Watermain Installed by Year



4.2 Material Profile A cross-reference table was rationalized such that the material types from the Municipality’s GIS datasets could be classified as shown in Table 4-1. The primary observation that can be made from this categorization is that the majority of the Municipality’s watermains are constructed of PVC.

Table 4-1: Watermain Material Types by Length (m)

Material Class GIS Value Length (m) Cementitious AC 1,634.4 Ferrous Metal DI 15,625.1

CI 746.8 Non-Ferrous Metal CU 15.7

Thermoplastic PVC 39,594.2 HDPE 150.9 POLY 4.9

Total 57,771.9 A more representative global material type distribution within the Municipality’s watermains inventory can be observed from Figure 4-2. More than half of the total length of watermains is constructed using thermoplastic materials (69%, 39.7 km). Approximately, 28% (16.4 km) is constructed using ferrous metal materials. As this group is the second highest group in the population, understanding the corrosion mechanism is an important factor to consider within the risk model. About 3% (1.6 km) of the watermain inventory is constructed using cementitious materials with a negligible contribution of non-ferrous materials.

Figure 4-2: Watermain Material Types by Length Percentage When watermain material is compared with the year of installation, one can draw some general conclusions about failure risk exposure when there is existing background knowledge of the average useful-life of the watermain materials within the local conditions. Figure 4-3 demonstrates the decade in which a group of watermains are constructed along with their material type and total length. According to the figure, the most commonly used material type from 1970 to 2017 is thermoplastic. Prior to these decades, thermoplastic materials were not used as extensively as others. It can be observed that the Municipality relied heavily on PVC material starting from the 1990s when installing new watermains.



Figure 4-3: Length of Watermain by Material Class and Decade

4.3 Diameter Profile Larger diameters present greater risk exposure when considering economic, environmental, operational, and social risk indicators. As an indicator, obtaining diameter information is essential for further applications in the assessment methodology. According to the GIS data, the existing watermain diameters ranged between 50 mm and 300 mm. Figure 4-4 displays the diameter profiles as a percentage of the total length. According to the figure, 72% (41.6 km) of the watermains have 150 mm and 200 mm diameter sizes. Approximately 27% (15.8 km) are of 250 mm and 300 mm diameters. A very small proportion of the Municipality’s inventory (approximately 1%, 0.4 km) has diameters of 50 mm and 100 mm.

Figure 4-4: Watermain Diameter Pie chart

Additional clarity of risk exposure related to watermain size can be attained by considering the specific material types within each diameter range. Where material types that have a higher risk of failure are in a higher consequence grouping (based on diameter), this can be used to better understand and develop overall priorities. Figure 4-5 breaks down each diameter grouping by the corresponding material type. The figure suggests that the only diameter size used for cementitious watermains is 150 mm. Most of the thermoplastic (14.4 km) and ferrous (9.9 km) watermains have a diameter size of 150 mm. Furthermore, the total length of thermoplastic watermains that have diameter sizes greater than 150 mm is 25.0 km, while it is 6.4 km for ferrous watermains.



Figure 4-5: Watermain Diameter and Material Class

4.4 Municipality Staff Experience An interview with Municipality staff was conducted to discuss previous watermain asset failure experiences and lessons learned. Although the complete minutes for the interviews are provided in Appendix A, Table 4-2 lists some of the major watermain highlights. The following staff were interviewed:

◼ Carlos Reyes ◼ Meghan Fletcher ◼ Kevin Wilson ◼ Jeff Carsey ◼ Jarrod Craven

Table 4-2: Municipality Staff Interviews – Key Highlights

Item Description Watermain/ Accessories

Failure

• The Municipality experienced more breaks in PVC segments • The Municipality has historical breakage information in the GIS, but it is not comprehensive • The Municipality recorded visual subjective information about the causes of failure but did not perform rigorous

root cause analysis. Furthermore, the Municipality did not perform any destructive testing for broken or fractured segments

• The Municipality experienced quality issues from one of the residents every couple of months. The Municipality flushed the system and validated the water quality based on visual observations but not laboratory tests

• The Municipality did not experience any valve breaks/failures that are related to a specific brand or location • The Municipality did not experience any pressure drop complaints. If it happened, past issues were resolved

using internal plumbing Breakage Response

• The Municipality has its own SOPs to respond to watermain failures • In general, the following repair process is followed in many of the breakage events: Call/alarm → send operator → call contractor →Isolate the area → repair

• All previous failure events were prepared in less than 24 hrs • The Municipality does not have accessibility issues. If issues are to arise, they can deal with it.

Others • The Municipality does not have a hydraulic model; however, they are developing one as part of the updated master plan

• The Municipality conducted a fire flow pressure test in 2015 • There are no concerns with the soil conditions. The Municipality stated that the existing soil is non-corrosive. • There are no pressure zones (it is only a single zone)



5. Conclusions and Recommendations

5.1 Conclusions This Technical Memo (TM #1) summarized the outcomes of a comprehensive review of the existing watermain information for the Municipality of Thames Centre. It provides a review of industry-best practices related to asset risk management, and contains an overview of the composition, deterioration, deficiencies, and characteristics of materials that comprise the Municipality’s watermain inventory. Watermains were characterized to identify particular material types, construction eras, and diameter profiles that represented higher risk and would warrant particular attention during the desktop screening analysis. Some of the inventory highlights include the following:

1. The Oldest Watermains The oldest watermains were constructed in the Municipality between 1955 and 1959 with a

total length of 0.94 km;

2. Total Length of Municipality Owned Watermains The total length of watermains owned by the Municipality is 57.8 km. Approximately, 33.2 km

were constructed before 2000;

3. Dominant Material Type The majority of watermains material type is thermoplastic with an approximate total length of

39.7 km;

4. Watermains Diameters The total length of the watermain with diameters of less than or equal to 150 mm is 26.3 km.

Larger sizes have a total length of 31.4 km; Understanding asset composition of the network is important to establish an effective rehabilitation policy. Variations in material type, diameter size, and year of installation will have significant impact on prioritizing watermains. The management and prioritization of linear systems including pressurized pipes should be established on a risk-based approach (Equation [1]) to develop a robust condition assessment and rehabilitation policy. Therefore, next steps will include developing a risk-based approach by considering the LoF and CoF. The latter parameter, however, will be used as a prioritization indicator to rationalize the condition assessment cost savings for the Municipality. Overall, the Risk Management Framework will facilitate cost-effective management of the watermains of the Municipality to ensure that appropriate levels of services are met in the short-term, as well as to maximize the service life in the long-term. The annual program will allow operators and asset managers to align tactical operating, maintenance, and management strategies with long-term strategic goals.

5.2 Recommendations Based on review of the Municipality’s existing inventory against industry standards, the following recommendations are proposed:

1. The Municipality should begin to record information on diameter ratios, and specifications/standards for thermoplastic pipe within the GIS database to aid with future modelling and analysis (for all pressurized pipe);



2. The Municipality should consider implementing standards and specifications for preferable material types and construction methods to adhere to local conditions (e.g., Pipe depth, soil conditions, water table, etc.);

3. The Municipality should provide/update the C-factor test information for each watermain segment in the GIS database;

4. The Municipality should continue tracking failure records of its system, and expand protocols to improve data collection practices to better understand root causes and problematic areas. This can be accomplished by performing destructive tests on fractured pipe segments instead of relying on visual subjective decisions; and

5. The Municipality should consider recording each main break and document incidents within the GIS datasets.



6. References

ISO31000, 2009: Risk management – Principles and guidelines, p. 2. ISO.

AWWA, 2010: AWWA J100-10 Risk Analysis and Management for Critical Asset Protection (RAMCAPÂ®) Standard for Risk and Resilience Management of Water and Wastewater Systems. US: American Water Works Assn.

Canadian Water and Wastewater Association, 2005: Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/Risk Management Approach. CWWA.

Halfawy, M., Dridi, L., & Bajer, S., 2008: Integrated Decision Support System for Optimal Renewal Planning of Sewer Networks. Journal of Computing in Civil Engineering, 360-372.

Kleiner, Y., & Rajani, B. B., 2003: Quantifying Effectiveness of Cathodic Protection in Watermains: Theory. Journal of Infrastructure Systems, pp. 1-32 (NRCC-38457).

Ministry of Environment, 2007: Implementing Quality Management: A Guide for Ontario’s Drinking Water Systems. Municipal Drinking Water Licensing Program. Ontario: MOE.

Muhlbauer, W. K., 2004: Pipeline risk management manual. Burlington, Ont: Gulf Professional Publishing.

Organization, W. H., 2004: Guidelines for drinking-water quality, 3rd Ed. Geneva: World Health Organization.

Rajani, B., & Kleiner, Y., 2004: Non-destructive inspection techniques to determine structural distress indicators in water mains. NRC - CNRC, 1-20.

Sadiq, R., Saint-Martin, E., & Kleiner, Y., 2008: Predicting risk of water quality failures in distribution networks under uncertainties using fault-tree analysis. Urban Water Journal, 287-304.

Statistics Canada, G. O., 2017, November 29: Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province]. Retrieved October 2018, from https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539027&Geo2=PR&Code2=35&Data=Count&SearchText=Thames%20Centre&SearchType=Begins&SearchPR=01&B1=All&GeoLevel=PR&GeoCode=3539027&TABID=1

WERF., 2010: Remaining asset life: a state of the art review. WERF - Water Environment Research Foundation.



Appendix A Minutes of Staff Interview


1

Ref Action Initial 01 Opening Remarks

- CR commenced the meeting and welcomed AECOM team. Later, DO continued the meeting and shared the Agenda. DO provided an overall summary about the awarded project before moving toward the prepared presentation

02 Introductions/Safety Minute - KK started the presentation by stating the

content of the presentation. The presentation objectives were as follows:

To provide an update to TM1 by providing bar charts, pie charts and some numeral information

To conduct an overview about the condition assessment program that included:

Distress indicator Technology overview Condition assessment Decision tree

03 Project Overview - The presented slide displayed the overall

methodology of the project that included eight major tasks

- As part of the tasks, AECOM to provide a list of some critical segments to be inspected by Echologics

AECOM to list the identified critical pipes from the updated GIS

DO

04 Interview/Discussion - GIS data sent to AECOM was incomplete. The

GIS database is updated by the Municipality to year 2017. The updated GIS is related to the installation date and material

- The Municipality has observed and responded to breaks more in PVC pipelines. Breakage records to be included in the updated GIS database. However, the database is

AECOM to obtain the updated GIS database from the Municipality

CR

Minutes

Meeting name Asset Inventory Profile Interviews

Subject Asset Inventory

Attendees Municipality of Thames Centre: Carlos Reyes (CR), Meghan Fletcher (MF), Kevin Willson (KW), Jeff Carsey (JC), Jarrod Craven (JRC) AECOM: David O’Gorman (DO), Rabia Mady (RM), Khalid Kaddoura (KK)

Meeting Date October 23, 2018

Time 11:00 AM (EST)

Location The Municipality of Thames Centre – Council Chamber

Project name Water Condition Assessment and Inventory Cast Iron Replacement Needs

Prepared by KK/RM

AECOM project number 60586191


Minutes The Municipality of Thames Centre – Water System Asset Inventory Asset Inventory Profile Interview

AECOM 2

Ref Action Initial incomprehensive

- The Municipality has an automated system to record variations in the pressure happening in the system

- The Municipality does not have high pressure points; the system relies on a single pressure for the entire network

- The feed is located at the south end

- The Municipality did not perform any destructive testing for broken or fractured segments. Staff visually recorded their conclusions in sheets

- The Municipality did not perform any corrosion analysis for failed or fractured segments

- The Municipality had quality issues within the AC area, in Dorchester. Every couple of months they receive a complaint from one resident. They validated and flushed the hydrants. The Municipality did not perform any lab tests after the complaint. The assessment was based on visual observation

- The Municipality does not have constraints accessing segments in the system for some of the performed interventions

- The Municipality have conducted a Fire Flow Pressure test in 2015; but not the C-factor. The Municipality to check in their records if C-factor test has been performed

- The Municipality does not have a hydraulic model. The Municipality is building a model as part of the master plan

- The Municipality have some material in storage as part of the response of any problems in the network

- The Municipality responses to any emergency repairs are by established SOPs. Closure due to repairs do not exceed 24 hrs

- The Municipality believes and confirmed that the soil surrounding the segments is non-corrosive

- The Municipality does not have pressure drop issues

AECOM to receive sheets that include information about the observations recorded for broken segments

AECOM to receive road maps as traffic arrangements may be required

AECOM to receive updates from the Municipality with regards to C-factor test, if performed

The Municipality to send a geotechnical report to AECOM, if available.

CR

CR

CR

CR

05 AC & CI Condition Assessment Program - The current spacing between hydrants are

expected to be more than 100 m-150 m

- Inspection working hours are from 7:30 am to 4:30 pm (hours provided by the Municipality)

- Placement of ePulse technology

Spacing between hydrants to be verified during the site visit. If spacing is more than the required, holes are needed at additional costs To be identified during site visit to

Echologics



AECOM 3

Ref Action Initial

- Additional area of concern is mentioned by the Municipality that is constructed using PVC, in Dorchester.

- For segments with unknown materials, the Municipality suggested that it may require field inspection as material variations may result in anomalies

- For fixed pipelines, the Municipality uses PVC. However, this is not implemented in the GIS. This may provide some anomalies during inspection. The lists of pipelines to be visited for verifications are for CI and AC

- The inspection will be conducted up to 1 km. The ePulse system will be placed for 1 week to monitor the system. The inspection will provide information about the surge pressure; water sampling is not included in price.

- The Municipality is looking for replacing but not relining

- The estimated cost analysis of the inspection to be conducted is as follows:

o $25/m for average wall thickness measurement and leak detection

o $750/site for C-factor test for 4 segments (less than 2 segments, 1000/segment)

o $800/sensor for pressure monitoring for 1 week (min. 2 sensors)

determine if traffic arrangement is required. Traffic arrangement and control is an extra cost.

Echologics

06 Next Steps - Identify critical pipes

- Schedule field visit in the week of November 12

- Schedule two day inspection in the week of

November 19

AECOM to provide a list of critical pipelines after receiving an updated GIS database

The Municipality to confirm the date of field visit

The Municipality to confirm the date of inspection

DO

CR

CR

07 Others - Present a material about the importance of

hydraulic model, if decided and agreed

- Presentation by Echologics to Municipality

DO

CR/RM



AECOM 5

Date/Time: October 23, 2018 11:00 am – 1:00 pm

Watermains Failure

1. Have you responded to any watermain breaks/failures, if so, which

ones?

Not in all areas. The Municipality experienced more breaks in PVC. Breakage records will be observed in the updated GIS.

2. Were there any notable watermain failures? Updated GIS database to be checked. More breaks were in PVC segments.

3. Have you recorded the number of breakage of failed segments? Not comprehensive. Municipality to provide GIS data with breakage information. It is a separate layer in the GIS.

4. Do you have an automated system that records operational variables

such as pressure?

Yes. The Municipality has on facilities; but sensors are not inside the system. The Municipality’s network does not have high

pressure points. The network has a single pressure for the entire system. The feed is at the south end.

5. Have you conducted root cause analysis for failed or fractured

pipelines?

The Municipality has sheets that describe the information about the breaks. In general, the Municipality does not send broken

segments for tests. Staff records what they see based on visual inspection. AECOM to have access to these sheets that provide

breakage information. The Municipality staff stated that the soil is non-corrosive . Earth is dry sandy soil. Cover is 6.5 ft. In some

areas, high water table exists.

6. Have you performed corrosion analysis on failed ferrous materials? If

yes, what have you done?

Not tested. Only sheets are available that visually describe breakage.

7. How many water quality complaints/year do you receive? How many

were validated based on the number of complaints?

The Municipality had within the AC area, in Dorchester; every couple of month. The staff validated and flushed the hydrants. The

Municipality did not perform any lab tests after the complaint. The assessment was based on visual observation.

8. Have you had any trouble accessing a watermain for rehabilitation? The Municipality does not have accessibility issues.

9. Have you conducted a C-factor test? The Municipality conducted a Fire Flow pressure test in 2015. But not the C-factor test. Municipality will check the sheets

10. Do you have a calibrated hydraulic model? No hydraulic model. The Municipality is building a hydraulic model as part of master plan.

11. Do you have a water master plan? Do you have high transmission

feeder?

The Municipality is performing an update on water master plan. The Municipality has a 300 mm from the plant. The 400 mm is in

Thorndale. It has no redundancy .The Municipality did not have any breaks in transmission/feeder.

12. Have you established protocols for failure? Do you have an in-house

material storage?

Call/alarm send operator call contractor Isolate the area repair. Sheets to be sent by Municipality. AECOM can check

the number of repair hours. The Municipality have some material in storage.

13. Do you currently have any emergency response plans or contingency

plans for watermain failures?

The Municipality has SOPs.

14. Are these response plans for all facilities/assets or specific

facilities/assets?

The Municipality has SOPs.

15. Are there any facilities that there currently have no emergency

response plans or contingency plans?

16. In the event of a failure, are there any assets that have taken (or

would take) a long time to source/replace?

This information is recorded in sheets.

17. Did you have any breakage events that the valve closure takes

beyond the normal times?

Not more than 24 hr. Valve closes tight enough and seal properly (issues in the construction side of valves)



AECOM 6

18. Do you have procedure in fixing breaks? Do you sub-source? The Municipality sub-sources in the event of breaks

19. In the event of a failure, are there any parts that may take longer time

to get at? 24hrs+?

Nothing more than 24 hours

20. Are there any concerns with soil conditions within particular areas

that are contributing to watermain failures?

No concerns with the soil conditions (non-corrosive). Municipality to check if a geotechnical report is available.

21. Do you have any renewal matrix based on number of watermain

breaks?

SOPs

22. General Questions

23. Do you have pressure measured areas? Do you have pressure

zones?

No pressure zones. Only single zone.

24. Are there any concerns with valve breaks/failures related to a

particular brand or location?

No.

25. Do you have transient pressure study?

26.

What kind of brands do you use for the inventory? Are you aware of

any particular brand of appurtenance, equipment, or business

practice that has contributed to asset failure in the linear water

system?

The Municipality uses Miller and Clow. The Municipality does not have issues with these brands.

27. Who do you call for traffic control? Contractor.

28. Have you had variations and drops in water pressure (complaints)? Resolved in internal plumbing. The Municipality did not receive any complaints in the network.


AECOM Canada Ltd. 105 Commerce Valley Drive West 7th Floor Markham, ON L3T 7W3 T: 905.886.7022 F: 905.886.9494 aecom.com



Technical Memorandum #2: Initial Criticality Findings

Prepared by:


Date: January, 2020

Project #: 60586191


Distribution List



Revision History

Revision # Date Details Name Position 1 Jan 14, 2019 Initial Draft Khalid Kaddoura Asset Management Consultant 2 Jan 30, 2019 Draft Submission Khalid Kaddoura Asset Management Consultant 3 Jan 15, 2020 Final Submission Michele Samuels Senior Asset Management Consultant


AECOM The Municipality of Thames Centre Technical Memorandum #2: Initial Criticality Findings

TM2_2020-01-30_Initial Criticality Findings_60586191_V3.Docx

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AECOM The Municipality of Thames CentreTechnical Memorandum #2: Initial Criticality Findings


Authors

Report Prepared By: Khalid Kaddoura, PhD, PMP

for Erik Wright, B.Sc. (no longer employed

by AECOM)

Report Verified By: for Rabia Mady (no longer employed by

AECOM)

Report Approved By: Michele Samuels, M.Eng., P.Eng., MBA





1. Introduction ....................................................................................... 1



2. Summary of Risk Assessment Best Practices ................................. 3

2.1 Overview ................................................................................................................. 3

2.2 Summary of Best Practices ..................................................................................... 3

2.2.1 AWWA J100:10 Risk and Resilience Management of Water and Wastewater Systems (2010) ...................................................................................................... 3

2.2.2 ISO31000:2009 Risk Management – Principles and guidelines .............................. 4

2.2.3 Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment / Risk Management Approach ............................................................ 4

3. Risk Model ......................................................................................... 5

3.1 Overview ................................................................................................................. 5

3.2 Consequences of Failure ........................................................................................ 7

3.2.1 Index Weightings .................................................................................................... 8

3.2.2 Index Hierarchies ................................................................................................... 9

3.2.3 Data Requirements .............................................................................................. 10

3.2.4 Consequence of Failure Multi-Criteria Rating ....................................................... 10

3.2.5 Defining the Consequence of Failure Rating ........................................................ 10 3.2.5.1 Consequence of Failure Rating Breakpoints ................................................... 11

3.2.6 Workshop Calibration ........................................................................................... 12

3.3 Likelihood of Failure .............................................................................................. 12

3.3.1 Calculation of Likelihood of Failure ....................................................................... 13

3.3.1.1 Shape Factor (𝜸) ............................................................................................ 13 3.3.1.2 Scale Factor (𝜷) ............................................................................................. 14 3.3.1.3 Deterioration Based on Breakage Data .......................................................... 14 3.3.1.4 Deterioration Based on Age and ESL ............................................................. 16

3.3.2 Defining the Likelihood of Failure Rating .............................................................. 16

3.3.3 Likelihood of Failure Rating Breakpoints .............................................................. 17

3.4 Risk Score ............................................................................................................. 18

3.4.1 Risk Score Rating Breakpoints ............................................................................. 18

3.5 Selection of Pipes for Pilot Inspection ................................................................... 18

4. Inspection and Monitoring Strategies ............................................ 20

4.1 Retroactive Asset Failure Assessment and Root Cause Analysis ......................... 20

4.2 Polyvinyl Chloride .................................................................................................. 21

4.3 Cast Iron and Ductile Iron ...................................................................................... 23




5. Results ............................................................................................. 24

5.1 Consequence of Failure (CoF) .............................................................................. 24

5.2 Likelihood of Failure (LoF) ..................................................................................... 26

5.3 Overall Risk ........................................................................................................... 28

5.4 Pipelines Suggested for Pilot Inspection ............................................................... 30

5.5 Inspection and Monitoring Strategy ....................................................................... 31

6. Summary, Conclusions and Recommendations ............................ 33

6.1 Summary and Conclusions ................................................................................... 33


7. References ....................................................................................... 35

List of Figures Figure 3-1: Common ‘Types’ of Infrastructure Failure .......................................................................................... 6 Figure 3-2: CoF Overall Methodology ................................................................................................................. 7 Figure 3-3: CoF Factors and Weights ................................................................................................................. 8 Figure 3-4: CoF Factors and Sub-factors Hierarchy ............................................................................................ 9 Figure 3-5: CoF Rating Definition...................................................................................................................... 11 Figure 3-6: LoF Preliminary Model .................................................................................................................... 12 Figure 3-7: Deterioration Curve for DI 150 mm - Dorchester Area ..................................................................... 15 Figure 3-8: Deterioration Curve for PVC 150 mm and 250 mm - Dorchester Area ............................................. 15 Figure 3-9: LoF Distribution .............................................................................................................................. 16 Figure 3-10: LoF Rating Definition ...................................................................................................................... 17 Figure 3-11: Selection of Pipes for Pilot Inspection Methodology ........................................................................ 19 Figure 5-1: CoF Distribution by Length ............................................................................................................. 24 Figure 5-2: CoF Distribution by Number of Segments ....................................................................................... 24 Figure 5-3: CoF by Diameter ............................................................................................................................ 25 Figure 5-4: CoF Distribution by Length and Material ......................................................................................... 25 Figure 5-5: Calculated CoF Distribution ............................................................................................................ 25 Figure 5-6: LoF Distribution by Length .............................................................................................................. 26 Figure 5-7: LoF Distribution by Number of Segments ........................................................................................ 26 Figure 5-8: LoF Distribution by Diameter........................................................................................................... 27 Figure 5-9: LoF Distribution by Material and Length .......................................................................................... 27 Figure 5-10: LoF Distribution .............................................................................................................................. 27 Figure 5-11: Risk Distribution by Length ............................................................................................................. 28 Figure 5-12: Risk Distribution by Number of Segments ....................................................................................... 28 Figure 5-13: Risk Distribution by Diameter .......................................................................................................... 29 Figure 5-14: Risk Distribution by Material and Length ......................................................................................... 29 Figure 5-15: Risk Score Distribution ................................................................................................................... 29 Figure 5-16: Risk Scatter Plot ............................................................................................................................. 30 Figure 5-17: Risk Categories by Total Length of AC and CI ................................................................................ 30




List of Tables Table 3-1: Influence of Asset Criticality on Management Strategy ...................................................................... 5 Table 3-2: Influence of Asset Criticality on Assessment Strategy ....................................................................... 6 Table 3-3: Global and Local Weights of Factors and Sub-factors ....................................................................... 9 Table 3-4: CoF Model Data Requirements ....................................................................................................... 10 Table 3-5: CoF Breakpoints ............................................................................................................................. 12 Table 3-6: Shape and Scale Parameters Values .............................................................................................. 15 Table 3-7: Assumed Material ESL ................................................................................................................... 16 Table 3-8: LoF Rating Breakpoints .................................................................................................................. 17 Table 3-9: Risk Scores Breakpoints ................................................................................................................. 18 Table 4-1: Risk Driven Staged Approach to Condition Assessment .................................................................. 20 Table 4-2: Recommended Data Collection during Pressurized Pipe Failure by Material Type .......................... 21 Table 4-3: Life Funds of PVC Pipe .................................................................................................................. 22 Table 4-4: Assessment Levels for Pressurized PVC Pipe ................................................................................ 22 Table 4-5: Ramifications of Extrusion Quality and Applied Stress..................................................................... 22 Table 4-6: Assessment Levels for Ferrous Pipes ............................................................................................. 23 Table 5-1: Ranked AC & CI Pipelines Based on Risk Scores ........................................................................... 31 Table 5-2: Staged Approach Assessment Matrix Results (Number of Watermain Segments) ........................... 31 Table 5-3: Total Length of Staged Approach to Condition Assessment by Material .......................................... 32

Appendices Appendix A. Workshop #1 Minutes of Meeting Appendix B. CoF, PoF, and Risk Maps – Dorchester and Thorndale



TM2_2020-01-30_Initial Criticality Findings_60586191_V3.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 59.6 km of watermain infrastructure (1.8 km of watermains are privately owned) to supply water and provide management services to a population of 13,191 residents (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2 (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). Unlike wastewater and/or stormwater collection systems, pressurized watermains are often operationally and cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing them in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF) and can present significant risks in the event of an unexpected failure. Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess pressurized watermains. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition, assess failure risk, and estimate residual design life in watermain infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing the inspections to minimize the risk exposure while optimizing budgetary allowances. On this basis, pressurized watermains can be managed preventatively, through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of the assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based state of good repair program to: 1. Prioritize and assess watermains;

2. Analyze pipe lifecycle; and

3. Provide an annual funding forecast.

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with the procedures and tools to prioritize watermains for inspections including the means to assess existing pipe material inventory and prioritize these inspected watermains for renewal in the short-, mid-, and long-term.




The primary objective of this study is to develop a maintenance renewal schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-objectives including, but not limited to, the following:

1. Reviewing inventory data; 2. Identifying failure modes and distress indicators; 3. Developing Consequence of Failure (CoF) model including prioritizing pipes for assessment; 4. Matching suitable technologies, and planning a pipeline condition assessment trial for a critical

watermain previously identified by the risk model; 5. Interpreting inspection findings to estimate the likelihood of failure (LoF); 6. Defining the level of service; and 7. Building a comprehensive risk-based decision matrix tree for pipe renewal.

1.2 Objectives for Technical Memorandum #2 Technical Memorandum No. 2 (TM#2) is designed to model a risk-based framework that relies on the Likelihood and Consequence of Failure (LoF and CoF), for the Municipality of Thames Centre. This model will be used to evaluate the unique risks associated with buried pressurized pipe infrastructure. Therefore, the main goals of this TM are as follows:

1. Provide an overview of the risk model approach and parameters; 2. Highlight the risk criteria, rationale, and weightings; 3. Provide an overview of the sensitivity of each of the risk categories; and 4. Provide an overview of the risk profile for water assets.




2. Summary of Risk Assessment Best Practices

2.1 Overview Infrastructure related risk exposure is assessed based on the combined consideration of likelihood and consequences of an asset’s failure (LoF and CoF). The LoF parameter, for pressurized pipelines, is heavily linked with the ability of the watermain to sustain its designed limit states before failure. The lower the designed Factor of Safety (FoS), the more the asset is prone to breakage. Meanwhile, the CoF is associated with the direct and indirect costs of losses of an asset. Direct costs could include damage to private or public property or impacts to public health and safety or the environment. Indirect costs could relate to contractual violations, customer dissatisfaction, and fines or penalties. (Muhlbauer, 2004). Due to the pressing need to best allocate budgets in preserving underground infrastructure, several methodologies have been followed to calculate the risk parameter.

2.2 Summary of Best Practices In recent years, infrastructure related risks have increasingly become the subject of discussion among organizations responsible for physical infrastructure. A risk-based assessment and management strategy should be well-structured and systematic. Several methodologies, that are widely implemented and accepted, have been developed to assess and manage risks. The risk assessment process described in each is similar. However, minor differences are present, and some sources modify the basic risk equation in terms of assessing resiliency separately from failure consequences. Some of these methods are described in:

1. The American Water Works Association (AWWA) J100:10 – Risk and Resilience Management of Water and Wastewater Systems (RAMCAP) (AWWA, 2010)

2. The International Organization for Standardization (ISO) 31000:2009 Risk Management – Principles and guidelines ( ISO31000, 2009)

3. The Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/Risk Management Approach (Canadian Water and Wastewater Association, 2005)

2.2.1 AWWA J100:10 Risk and Resilience Management of Water and Wastewater Systems (2010)

The AWWA J100 - RAMCAP was developed by the American Society of Mechanical Engineers (ASME) as a result of the attacks of September 11, 2001. The framework is specific to water and wastewater systems and considers a wide range of failures. These failures include man-made threats, natural hazards (earthquakes, tornados, etc.), and dependency hazards (interruptions of supply chains or proximity to dangerous sites). This approach breaks down LoF into two elements: vulnerability analysis and threat analysis. Threat analysis estimates the likelihood that a particular threat occurs. Vulnerability analysis, however, predicts the likelihood that each specific threat, if it occurs, will have the consequences predicted. Thus, risk is calculated as the product of consequences, vulnerability, and threat.




2.2.2 ISO31000:2009 Risk Management – Principles and guidelines

The ISO 31000:2009 Risk Management standard provides generic guidelines to risk assessment and management and is not specific to an industry or sector. The role of risk management within an organization is emphasized, as well as the need for communication, monitoring and review throughout the risk management process. The standard defines risk evaluation as “the process of comparing the results of risk analysis with risk criteria to determine whether the risk and / or its magnitude is acceptable or tolerable” ( ISO31000, 2009).

2.2.3 Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment / Risk Management Approach

The Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/Risk Management Approach (Canadian Water and Wastewater Association, 2005) multiplies CoF and LoF to find an overall risk score. This document also refers to the relative scoring of assets. It suggests that an accelerated scale (e.g., 1,3,5,7, 9 instead of 1,2,3,4, 5), an exponential, or a log-rating scale be used when evaluating risk to give greater emphasis to high LoF and CoF events.




3. Risk Model

3.1 Overview In analyzing risk for infrastructure assets, the first step is to identify assets that are most critical to the business. Critical assets are those that will potentially have the greatest impact on service delivery should they fail. The fundamental principle of consequence (or criticality) models is that they evaluate the relative importance of assets based on select criteria. The approach to risk analysis within this project is aligned with Industry best practices (outlined in Section 2), and utilizes a triple-bottom-line assessment approach containing the following four (4) criticality pillars:

◼ Economic – influence of the asset’s failure on monetary resources; ◼ Operational – influence of the asset’s failure on operational ability; ◼ Social – influence of the asset’s failure on society; and ◼ Environmental – influence of the asset’s failure on the environment

By applying specific indices, the risk assessment framework generates a risk (or priority) score for each asset. The risk score is a rating of the asset based on the detailed assessment of the likelihood and consequence of failure based on several key parameters. All parameters are then equated using equation [1].

𝑅𝑖𝑠𝑘 = 𝐿𝑖𝑘𝑒𝑙𝑖ℎ𝑜𝑜𝑑 𝑜𝑓 𝐹𝑎𝑖𝑙𝑢𝑟𝑒 × 𝐶𝑜𝑛𝑠𝑒𝑞𝑢𝑒𝑛𝑐𝑒 𝑜𝑓 𝐹𝑎𝑖𝑙𝑢𝑟𝑒 [1] Based on this principal, the risk associated with a given asset’s failure can be managed by limiting the likelihood of this occurring, or the impact realized, should it occur. Consequence of Failure (CoF) reflects the relative “impact” of a given asset’s failure. While traditionally these have been looked at as purely economic terms (i.e., repair cost, loss of revenue, etc.), the truth is that investment decisions can often be driven by non-economic factors. Understanding both the economic and non-economic impacts associated with loss or limitation of service help in categorizing an asset’s “criticality” and justifying infrastructure decisions in a consistent, defensible manner. Even without understanding when failure will occur, categorizing assets based on ”criticality” or “failure consequence” allows municipalities to effectively target management strategies aimed at mitigating risk. Table 3-1 demonstrates how “consequence” related data can be combined in shaping our approach to managing an individual asset.

Table 3-1: Influence of Asset Criticality on Management Strategy

Criticality Rating Low Moderate High Service Implication Negligible impact to service

delivery Noticeable to significant impact to service

Catastrophic impact to service and/or public safety

Operational Impact Failure can be addressed through normal operations

Failure can be accommodated but strains operations

Failure cannot be handled in an effective manner

Management Strategy Run-to-Failure Manage failure Avoid failure




“Failure” reflects an asset’s ability to provide its required level of service (LOS). While this is often interpreted in a physical sense, as a measure of deterioration of an asset’s structure, loss of service can occur on a number of fronts; Figure 3-1 provides some common examples of “failure” occurrences.

Figure 3-1: Common ‘Types’ of Infrastructure Failure Understanding which failure types are most prevalent to a given type of asset, and how potential “failure modes” will develop over an asset’s lifecycle, provides valuable insight when developing management strategies. The type and amount of effort (and investment) placed on diagnosing and tracking factors contributing to loss of service should reflect the ultimate value of the information collected in supporting staff in making planning and management decisions; Table 3-2 expands on Table 3-1 to highlight factors influencing this decision.

Table 3-2: Influence of Asset Criticality on Assessment Strategy

Criticality Rating Low Moderate High

Service Impact Negligible Noticeable/ Significant Catastrophic Operational Impact Failure can be addressed

through normal operations Failure can be accommodated but strains operations

Failure cannot be handled in an effective manner

Management Strategy Run-to-Failure Failure Management Failure Avoidance Assessment Priorities Monitoring and forecasting Assessment and planning Proactive maintenance and

rehabilitation Accuracy Requirements High tolerance for performance

uncertainty Low tolerance for performance uncertainty

No tolerance for performance uncertainty

Because of the limited impact of failure in low criticality assets, taking a reactive approach to data collection and asset renewal will not pose significant risk and liability in the future. While adopting a ‘run-to-failure’ policy can be politically unpalatable, using lifecycle costing and hard economics to drive system inspection/renewal/rehabilitation can provide a consistent, defensible framework for planning and decision-making. A data collection strategy based on asset monitoring and forecasting will provide effective results. The Municipality may:

1. Focus on low-cost / high-coverage inspection techniques to monitor asset performance and identify assets requiring short-term attention;

2. Use failure pattern and/or statistical modelling, and observations of past performance, to forecast medium and long-range needs

Inspection and planning programs for moderate/high priority assets – those whose failure will produce noticeable to significant impact to service – should be optimized based on overall risk exposure. The Municipality needs to:

1. Increase the frequency of assessment as condition deteriorates and the rate of degradation increases on an unanticipated manner; and

2. Ramp-up tools and techniques to increase certainty of data collected as condition deteriorates and the need for accurate understanding of condition grows.

Maintenance requirements;

MOE Compliance

Insufficient capacity

Cost of maintenance

exceeds renewal Leak /Break

Structural Economic Operational Regulatory




3.2 Consequences of Failure Successful implementation of risk-based planning and decision-making requires the identification of critical infrastructure to determine the consequence of failure (CoF) component of the risk equation. This is typically performed within a computerized work process or model that is based on a rating system of various failure consequence parameters. Parameters use a system of multi-variant weightings to derive a final overall value (Refer to Figure 3-2). The CoF parameter is a semi-quantitative and is developed to reflect an organization’s policy and goals, as closely as possible.

Data AnalysisData Review

Factors/Sub-

factors

Weights

EnvironmentalEconomic Social Operational

Sub-factors

Scores

CoF Score

Aggregation

Figure 3-2: CoF Overall Methodology Piped infrastructure is geographically dispersed over a wide area with many external influences; therefore, the consequence model is typically generated from a spatial data analysis (GIS) that could be automated and repeatable, with little user intervention to minimize long-term data maintenance cost. Current industry best-practices for risk-based infrastructure management identify a consequence model as considering the following impacts of failure:

◼ Economic: It reflects the potential impacts in terms of the direct and indirect capital cost of pipe failure. It generally considers direct cost of repairing the pipe and remediation, and the potential collateral damage to neighbouring properties and structures. For example, it will be more expensive to repair a failed pipeline in a highly traveled area where traffic management costs are high. The scoring ranges for the economic risk model indices are typically proportional to the sum of the direct and indirect cost of repair.

◼ Environmental: It reflects the potential impact to the environment in the event of a pipe failure that are directly or indirectly related. These could be related to the loss of treated water, loss of energy, disturbance to the surrounding terrain and areas, contamination of spilled water with the surroundings that may degrade the quality of water, etc.




◼ Social: It reflects the potential impact to the public in the event of the pipe failure. It generally considers the magnitude of the spill and potential disruption to nearby roadway traffic and/or commercial activity.

◼ Operational: It reflects the potential impact to the system’s operations in the event of pipe failure. Generally, it considers both organizational impact and the system impact in terms of whether there is enough redundancy within the system to circumvent the failed asset for an extended period. In addition, the operational criteria consider the urgency and complexity of remediation of a failure.

Weights are applied to each impact’s category and are dependent on a balance of science and the perspective of the stakeholders. The weightings are intended to form a balance among different stakeholder requirements in an environment where operators may weigh the operational category higher than a water customer who may weigh the social impact higher. The weightings can be altered in the future as stakeholder views and overall organizational drivers change over time. The ultimate weight given to each category is qualitative but is also a reflection of the Municipality’s overall goals and stakeholder priorities. There is a practical consideration of weighting determinations, and the ultimate rating system should reasonably delineate the assets in broad categories of low, medium, and high consequence (i.e., if it does not differentiate priorities clearly, it is not an effective prioritization tool).

3.2.1 Index Weightings

To develop the CoF model for water systems, the CoF is considered and rationalized as individual factors. Each of the factors is weighted on a scale from 0% to 100%, with the total of all required to equal 100%. Each CoF score consists of individual factors and sub-factors that when combined, represent the overall consequence score. Each of these sub-factors consists of a 1 to 100 rating such that 1 would indicate minimal consequences while 100 would indicate the highest consequences. These factors and sub-factors are weighted against each other from 0% to 100% by importance, with the total of all being required to equal 100%. Based on the considered factors for the Municipality of Thames Centre, Figure 3-3 summarizes the weights of the four factors. The weights will further be used to find the global weights of the subfactors so that when aggregated, the resulting score will be from 1 to 100.

Figure 3-3: CoF Factors and Weights Each factor in the CoF model has its corresponding sub-factors that are expected to contribute to the consequence of the same group. The total sum of the weights of the sub-factor in each factor shall equal to 100% as indicated earlier. Table 3-3 provides a summary of the sub-factors as well as the global factors. The global factors are computed after multiplying the factor’s weight by the weight of the sub-factor. All global weights shall sum up to 100%. According to the table, the highest factor in the CoF model is related to operations with a weight of 35%, while the least weight among the factors are the social and environmental categories. With regard to the sub-factors, the highest aggregated weighted factor is the diameter with a total contribution of 34% compared to the other global weights while the least global weight is for the material type.

35% 20% 20% 25%

Economic Environmental Social Operational

Consequence of Failure




Table 3-3: Global and Local Weights of Factors and Sub-factors

Factor Factor Weight Sub-factor Local Weight Global Weight Economic 25% Diameter 30.0% 7.5%

Material 15.0% 3.8% Land Use 20.0% 5.0%

Accessibility 35.0% 8.8% Environmental 20% Diameter 20.0% 4.0%

Water Body 20.0% 4.0% Sensitive Area 60.0% 12.0%

Social 20% Land Use 25.0% 5.0% Diameter 25.0% 5.0%

Road Class 50.0% 10.0% Operational 35% Diameter 50% 17.5%

Pipe Type 25% 8.8% Tracing Type 25% 8.8%

3.2.2 Index Hierarchies

Figure 3-4 graphically summarizes the hierarchy of indices and weighting factors for the CoF framework.

Diameter (mm) Attribute value50 10100 30150 50200 65250 80300 100

Material Attribute value

PVC 100DI 25

HDPE 75AC 50CI 50CU 25

POLY 100

Economic

15%

20%

30%

Accessibility Attribute valueBridge 100

Railroad 100

35%

25%

Diameter (mm) Attribute value50 10

100 30150 50200 65250 80300 100

Pipe Type Attribute valueWatermain 75

Hydrant Lead 100Operational

50%

25%

25%

35%


Road Class Attribute valueA1 100A2 100A3 100B1 75B2 75B3 50C1 25C2 25C3 25

NONE 0

Social

20%

50%

25%

25%


Water Body Attribute valueYes 100No 0 Sensitive Area Attribute value

Yes 100No 0

Environment

20%20%

20%

60%

Tracing Wire Attribute valueYes 0No 100

Land Use Attribute ValueAgricultural 50Agricultural Restrictive Zone 50Environmental Protection Zone 75Future Development 25General Commercial 100General Industrial 75Institutional 75Mobile Home Park 50Office Residential 75Open Space 100Residential First Density 10Residential Second Density 30Residential Third Density 50

Land Use Attribute ValueAgricultural 50Agricultural Restrictive Zone 50Environmental Protection Zone 75Future Development 25General Commercial 100General Industrial 75Institutional 75Mobile Home Park 50Office Residential 75Open Space 100Residential First Density 10Residential Second Density 30Residential Third Density 50

Figure 3-4: CoF Factors and Sub-factors Hierarchy




3.2.3 Data Requirements

To calculate the CoF score, input data are required. These data are collected from the information acquired from the Geographic Information System (GIS) supplied by the Municipality of Thames Centre. Table 3-4 provides the sub-factors used in the model with its data sources, format, and field(s).

Table 3-4: CoF Model Data Requirements

Parameter Data Source(s) Format Attribute Field Geoprocessing Diameter TC_Watermain.shp Polyline PIPDIAMET n/a Material TC_Watermain.shp Polyline MATERIAL n/a

Land Use TC_Zoning_Dec4_2018.shp Polygon CODE Spatial Join with TC_Watermain.shp Accessibility TC_Bridges.shp

TC_Rail_Dorchester.shp TC_Rail_Thorndale.shp TC_Watercourse.shp

Polyline n/a Near Analysis with TC_Watermain.shp using a 30-metre tolerance.

Pipe Type TC_Watermain.shp Polyline TYPE n/a Tracing Wire TC_Watermain.shp Polyline TRACINGWIR n/a Road Class TC_RoadNetwork.shp Polyline CLASS Spatial Join with TC_Watermain.shp using

a 30-metre tolerance. Incremental procedure for writing Road Class starting

with low priority roads and ending with high priority roads (in cases where a pipe

intersected multiple road types, the highest priority road was selected).

Water Body TC_Waterbodies.shp TC_Watercourse.shp

Polygon Polyline

n/a Near Analysis with TC_Watermain.shp using a 30-metre tolerance.

Sensitive Area TC_SWMPond.shp TC_WellheadProtectionArea.shp

TC_WTP_Belmont.shp

Polygon n/a Near Analysis with TC_Watermain.shp using a 30-metre tolerance.

3.2.4 Consequence of Failure Multi-Criteria Rating

Using the Multi Criteria Rating Technique, a pipe CoF score can be calculated as per equation [2]. The asset’s CoF can be assessed based on the tabulation of index values using the weighted average approach. The Weighted Average approach uses the weighted average of all four categories (economic, operational, social, and environmental). Each category (i) contributes to the overall asset’s criticality according to its respective weight to establish a blended value.

𝑪𝒐𝑭𝒊= (𝒆𝒄𝒐.,𝒐𝒑𝒓.,𝒔𝒐𝒄.,𝒆𝒏𝒗.) = 𝑾𝒊 ∑ 𝑾𝒊𝒋𝑺𝒊𝒋

𝒏

𝒋=𝟏 [2]

where: CoFi = Consequence of failure score for each factor i (economic, operational, social, and environmental) Sij = Factor (j) score from 1 to 100 in each category i Wij = Subfactor weight as a percentage

3.2.5 Defining the Consequence of Failure Rating

A qualitative grading system is used to relate scoring to the Municipality’s ability to respond to asset failure, should it occur. Figure 3-5 describes the typical characteristics of assets within each CoF category ranked as either low, medium, or high. The description of the rating system can provide a general understanding of each category. It should be noted that not all metrics were assessed within the Risk Model based on the available data, and the nature of multi-criteria assessments means that each asset will contain a unique combination of CoF drivers.




Figure 3-5: CoF Rating Definition

3.2.5.1 Consequence of Failure Rating Breakpoints

Using the Multi-Criteria Rating System, an absolute aggregated number (0,100) is calculated to describe an asset CoF using the scoring scheme described in Figure 3-4. This number must be contextualized by the quantile distribution for the system, and the general benchmarks expressed in Section 3.2.5. When CoF is computed for the system, the percentile method is applied to determine where individual points lie in the CoF distribution. To better conceptualize the rating system, percentile breakpoints are assigned through the CoF distribution to categorize an asset’s calculated score as low, medium, or high. Breakpoints are set dynamically to ensure they are reflective of a dynamic risk portfolio. The breakpoint for low and medium risk is set at the 80th percentile, while the breakpoint between medium and high risk is set at the 95th percentile. This method of setting breakpoints proves a useful and consistent method to conceptualize CoF scores that combines benchmarked conceptions of failure consequence, statistical interpretation, and graphical interpretation. Any classification of a score using breakpoints will be subjective to the given tolerance for risk and may be adjusted by the user to reflect their specific level of tolerance. Workshop calibration (Section 3.2.6) found that the breakpoints were reflective of the Municipality’s understanding of risk. Furthermore, assets can vary in their scores within a given scoring category (for example, two assets with a score of 60 and 70, respectively, could both be classified as medium), meaning that in the context of asset prioritization, absolute scores will prove most useful in identifying priorities within a cohort of assets. Assigning breakpoints and classification provides a reasonable way to conceptualize CoF on a system wide level in a user-friendly manner. Table 3-5 displays the CoF breakpoint ratings for the system based on the current CoF distribution. For example, a calculated overall CoF with a value of 64 will be rated as Medium.

• Wide spread short disruption or long-term localization of disruption of service: - Regulatory objectives and requirements not met. - Loss of Service causes wide spread short disruption or long-term localization of

disruption of essential service. • Repair, loss of revenue, damages, losses or fines in the order of $500,000 to $1,000,000. • Significant spill, damage, or discharge to sensitive area, urgent/emergency remedial

action is required. • Significant number of complaints relative to operation of the asset. • Publicized by media outlets.

• Localized disruption of service: - Regulatory objectives and requirements met. - Loss of service causes localized disruption of non-essential service.

• Repair, loss of revenue, damages, losses or fines are in the order of $10,000 to $50,000. • Negligible injuries to property or the environment. • Minor impact of amenity complaints relative to operation of the asset.

• Localized disruption of service: - Regulatory objectives not met but service requirements met - Loss of service causes localized disruption of essential service.

• Repair, loss of revenue, damages, losses or fines are in the order of $50,000 to $500,000. • Serious spill, damage, or discharge to sensitive area, remedial action is required. • Disproportionate impact on amenity complaints relative to operation of the asset.

Medium

Low

High




Table 3-5: CoF Breakpoints

CoF Score Cut-Off Values

Rank Lower Upper

Low 0 59 Medium 59 73

High 73 100

3.2.6 Workshop Calibration

The weights and scores of factors affecting the CoF calculation were reviewed with the Municipality during Workshop #1 – Risk Model Overview and Calibration on December 13, 2018. This workshop was used as an opportunity to introduce the CoF approach, index weightings and hierarchies, and the multi-criteria rating. Workshop participants reviewed the index hierarchies and agreed that the proposed framework matched the organizational priorities of the Municipality. Meeting minutes can be viewed in Appendix A.

3.3 Likelihood of Failure Likelihood or probability of failure (LoF) in the context of structural failure of linear assets is largely dependent on the physical condition and applied loads on the pipe. This section provides an overview of the methodology used in determining the LoF of the Municipality’s water assets. Figure 3-6 shows the overall model considered to calculate the LoF scores. This model is split into two sub-models:

1. Assets where a historical record of breakage was available, and; 2. Assets where breakage records were not available.

Literature Review

Age

Experts

Judgement

Estimated

Service Life

Age & ESL

PoF Score

Analogous

Deterioration

Start

Any Breakage

History?

More than One

Break in a

Sample?

GIS InventoryNo

Yes

No

Filter Data by

Material and

Diameter

Rank BreaksYes Calculate

Probability

Fit 2-parameter

Weibull cdf

Least Square

Method

Figure 3-6: LoF Preliminary Model Historical breaks were reviewed, and the material types, diameters, and locations were considered to define the cohorts of pipes that could be grouped during LoF assessment.




Pipeline cohorts with more than one data point of breakage were assessed in the context of breakages. For example, the historical breaks recorded by the Municipality included three failures that occurred in Polyvinyl Chloride (PVC) 250 mm in Dorchester. These three data points were used to plot a deterioration curve, of the same material and diameter in the same area, using the two parameter Weibull analysis (see Section 3.3.1). Where breakage history data was unavailable or only one break occurred, the age and the estimated service life (ESL) was used as a method for LoF calculation (see Section 3.3.1). This presents the second approach to LoF assessment. The age parameter is extracted from the GIS database supplied by the Municipality. The ESL for each material was established based on literature review and applying AECOM’s experience with other municipalities. It represents a conservative estimation of a pipeline material’s ESL before failure in the absence of calibration from recorded pipe failures. These two parameters are used as input variables to model an analogous deterioration curve for each ESL.

3.3.1 Calculation of Likelihood of Failure

The calculation of the LoF, in both cases, is based on the application of a two-parameter Weibull distribution. In reliability analysis, it is commonly called the survival function. The most commonly used application is modelling the failure time data. The underlying premise of the Weibull type of analysis is that while some assets fail prematurely due to severe conditions or improper installation, other assets can be long-lived, and function well beyond their theoretical life expectancy. To perform a high-order network-level analysis, it was assumed that assets would fail (and require replacement) within an envelope approximated by a Weibull cumulative distribution. The Weibull distribution tool is utilized to describe the distribution of the extreme value data. The most commonly used application is modelling the failure time data. The inherent lifetime analysis offers the user the ability to estimate the probability that the asset’s lifetime exceeds any given time [P (T>t)]. The two-parameter Weibull distribution can be expressed based on equation [3].

𝑹(𝒕) = 𝟏 − 𝑷(𝑻 ≤ 𝒕) = 𝟏 − 𝑭(𝒕|𝜸, 𝜷) = 𝒆−(

𝒕

𝜷)

𝜸

[3] Where R (t) = Is the reliability at any time (t) P = Is the probability of failure at any time (t) F = Is the distribution function at any time (t) given a defined shape and scale factors 𝛾 = Is the shape factor; it is a non-negative value 𝛽 = Is the scale factor; it is a non-negative value Sections 3.3.1.1 - 3.3.1.2 provide further context on inputs used in the two-parameter Weibull distribution. The accuracy of the parameter’s estimation is dependent on the technique used to estimate them as well as comprehensive and accurate data records. If enough failure records are available, one can use several techniques to estimate the parameters such as the maximum likelihood estimator, methods of moments estimator, rank regression estimator, etc. See the comparison of modelling deterioration with or without breakage data in Sections 3.3.1.3 - 3.3.1.4.

3.3.1.1 Shape Factor (𝜸)

The shape factor represents the slope of the Weibull distribution, which is equal to the slope of the line in a probability curve. This dimensionless factor can impact the behaviour of the distribution and the degradation rate of the asset.

1. When 𝛾< 1, the distribution will have failure rate that decreases with time; this represents the early-life failures.

2. When 𝛾= 1, the distribution will have a constant failure rate, which indicates a random failure.




3. When 𝛾> 1, the distribution will have a failure rate that increases with time, which is called the wear-out failure.

These three inputs for 𝛾 represent idealized bathtub curve of the asset lifecycle, which typically consists of early life, useful life, and wear-out life. As water pipelines are subject to degradation and failure during their service life, the most representative plot in the bathtub curve is the “wear-out life”.

3.3.1.2 Scale Factor (𝜷)

𝛽 represents the scale factor in the Weibull distribution. When 𝛽 increases while keeping 𝛾 (the shape factor) constant, the distribution will stretch out and the peak in the probability density function (pdf) will drop. In general,

◼ When 𝛽 increases, holding the 𝛾 value, the pdf will stretch-out and the peak value will drop; ◼ When 𝛽 decreases, holding the 𝛾 value, the pdf will be pushed to the left (e.g., contracted) and the

peak value in the distribution will increase. Unlike the dimensionless 𝛾 parameter, 𝛽 has the same unit as T which is the same as the unit of measurement on the x-axis. For this assignment, in the context of time failure analysis of an asset, the x-axis of the distribution can be considered as age.

3.3.1.3 Deterioration Based on Breakage Data

The Municipality provided failure records for watermains that included three types of failure experienced by the City: main breaks, service connection failures, and valve malfunction/breakage. These failures occurred in the Dorchester area in three different pipeline materials: PVC, Ductile Iron (DI), and Cast Iron (CI). The majority of failures occurred in PVC types, with only one break recorded for CI. Most of the PVC failures occurred in 150 mm pipeline diameter. To incorporate records of watermain breakage, the least square method is used to fit the cumulative density function (cdf), which is then used to estimate the two parameters. The estimated parameter for each case is then applied in the two-parameter Weibull distribution function. The cdf is calculated based on the median rank estimate shown in equation [4]. 𝑀𝑒𝑑𝑖𝑎𝑛 𝑅𝑎𝑛𝑘 𝐸𝑠𝑡𝑖𝑚𝑎𝑡𝑒 =

𝑖 − 0.3

𝑛 + 0.4 [4]

where, 𝑖 = Breakage data rank 𝑛 = Total number of observations The breakage records are sorted based on their occurrence and then equation [4] is applied to calculate the cdf for each data point. The best fit line is then drawn between 𝑙𝑛 [𝑙𝑛 (

1

1−𝐹(𝑡))] and 𝑙𝑛(𝑡). Based on the linear function of the

fitted line, the shape and scale parameters are calculated and implemented in the two-parameter Weibull analysis method. Examining the properties of watermains with recorded breakages, three cohorts were identified for developing deterioration curves. These deterioration curves are specifically designed for the Dorchester area, where breaks have occurred. Two of the established curves are pertinent to PVC pipelines, with diameters of 150 mm and 250 mm respectively. The third curve represents the deterioration of 150 mm DI material. Note that the failure records that are considered are related to breaks and not for valves or services. Additionally, one data point for DI is excluded since the failure occurred in the same year as the pipeline’s installation. These data point is regarded as a random failure or possibly the result of infant mortality (e.g., construction practices).




Considering the abovementioned methodology, three different curves are used to represent a sample of the watermain population. The calculated scale and shape parameters are shown in Table 3-6.

Table 3-6: Shape and Scale Parameters Values

Material & Diameter Shape Scale DI 150 mm 9.35 53.78 PVC 150 mm 3.03 41.12 PVC 250 mm 8.64 23.69

Figure 3-7 represents the deterioration of a DI pipeline with a diameter of 150 mm in Dorchester. The curve suggests that the calculated deterioration rate starts to drastically increase at an age of 35 years (approximately), and the pipeline will be unreliable after approximately 60 years. Furthermore, Figure 3-8 shows the deterioration of PVC pipelines with diameters of 150 mm and 250 mm in Dorchester. Comparing the two PVC curves, the 250 mm sample deteriorates faster than the 150 mm based on the available records of breakage.

Figure 3-7: Deterioration Curve for DI 150 mm - Dorchester Area

Figure 3-8: Deterioration Curve for PVC 150 mm and 250 mm - Dorchester Area

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120

LoF

Age (year)

DI Fitted Deterioration - 150 mm




3.3.1.4 Deterioration Based on Age and ESL

Where historical failure data are unavailable or limited, the age and ESL factors are used as an indication of deterioration. In this study, the shape factor representing the slope of the line in the probability plot is considered as six (a typical input for generalized analogous deterioration in studies of infrastructure sustainability) and the scale factor is equivalent to the ESL of each material (see Table 3-7). The ESL values considered are conservative as some assets may exceed their expected service life before failure (as simulated by the Weibull distribution). These estimations and predictions can further be enhanced by having robust and extensive failure records.

Table 3-7: Assumed Material ESL

Material 𝛃 = ESL (Year)* PVC 85 DI 85 CU 80 CI 85 AC 85

HDPE 75 POLY 85

Note: * these are assumed values

Figure 3-9: LoF Distribution

3.3.2 Defining the Likelihood of Failure Rating

A qualitative grading system is used to relate scoring to the Municipality’s ability to respond to asset failure, should it occur. Figure 3-10 describes the LoF category results based on Low, Medium, and High. It is noteworthy to mention that an expected service life calculation should never be interpreted as a definitive rating for a pipe, but rather to evaluate potential condition relative to similar assets of varying ages within a portfolio until field-verified data can be obtained.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140

LoF

Age (year)

Assumed cdf

85

80

75




Figure 3-10: LoF Rating Definition

3.3.3 Likelihood of Failure Rating Breakpoints

Using the preliminary deterioration model for each material type, a number within this set [0,100] is obtained to describe an asset’s LoF using the two-parameter Weibull analysis. This number must be contextualized by the quantile distribution for the system using the percentile approach introduced during Section 3.2.5.1 for CoF. Table 3-8 displays the LoF breakpoint ratings for the system based on the current LoF distribution. For example, a calculated overall LoF with a value of 10 will be rated as Medium.

Table 3-8: LoF Rating Breakpoints

Rank Lower Upper Low 0 1

Medium 1 82 High 82 100

• Poor physical condition/failure imminent; heavy wear and tear, failure is likely in short term.

• Likely need to renew most of the asset in the short term.

• Substantial work is required in the short term.

• Sound/acceptable physical condition; no/minor wear and tear, no/minimum risk of physical failure.

• Normal/conservative original design basis

• No substantial deterioration likely over the next 5-10 years.

• No immediate repair work required.

• Acceptable physical condition; moderate wear and tear, moderate risk of physical failure.

• Failure unlikely within next two years but further deterioration likely and major rehabilitation /replacement required within the next 5 years. Minor isolated sections of the asset need replacement or repair now but the asset will still provide adequate levels of service.

• Minor spot repairs may be required, but asset is still serviceable.

Medium

Low

High




3.4 Risk Score Understanding the overall risk exposure of an asset is critical for decision making. The risk scores rely on the results of the two risk parameters, namely the LoF and CoF. The CoF and LoF computations, scorings, and ratings are demonstrated in Sections 3.2 and 3.3, respectively. Each asset will have unique CoF and LoF, which are used to calculate the corresponding risk score by applying equation [1]. The risk assessment calculations often require a calibration process such that the output is comparable with real-world situations. Once equation [1] is assessed, the asset can then be prioritized using its integrated risk score. The product of two parameters each scaled from 0-100 means that the integrated risk score is scaled from 0 – 10,000.

3.4.1 Risk Score Rating Breakpoints

A number in this set [0-10,000] is computed to describe an asset’s Risk Score using equation [1]. This number must be categorized by the percentile distribution for the system introduced during Section 3.2.5.1 for CoF. Table 3-9 displays the Risk score breakpoint ratings for the system based on the current Risk score distribution. For example, a calculated overall score with a value of 4,000 will be rated as High.

Table 3-9: Risk Scores Breakpoints

Rank Lower Upper Low 0 72

Medium 72 3907 High 3,907 10,000

3.5 Selection of Pipes for Pilot Inspection Performing advanced assessment using inspection tools is an essential step towards understanding the current condition of watermains. Many inspection tools are available that help in collecting condition data for watermains. These data are considered as one of the main inputs in deciding for any future intervention plans and/or pipe management. Despite its importance in asset management, Municipalities confront major budget allocation constraints to perform advanced condition assessment for the entire network. As a result, risk-based methodologies are suggested to help in prioritizing inspections and therefore, cost-effective decisions are attained. In this task, a risk-based approach is followed to select and prioritize pipelines for assessment as per Figure 3-11. The prioritization process incorporated the outputs of the CoF model as well as the LoF model to calculate a Risk Score for each watermain segment. Since the Municipality’s Request for Proposal (RFP) focused more specifically on selecting CI and Asbestos Cement (AC) pipelines for pilot inspection, the results of risk calculations were reviewed for these material types. Using the budget for pilot inspection identified by the Municipality, the selection criteria focused on maximizing the inspection length and benefits subject to the maximum total length of one kilometre as a constraint. When considering candidate sites and deployment methods the requirement for enabling work was also considered to maximize the utilization of the budget in condition assessment rather than civil work. For selection of sites after the pilot, this should be determined at a site visit conducted by the vendor. The main input in prioritizing the selection is solely dependent on the impact of CoF and LoF, which is represented by the integrated Risk Score. The list of the suggested ranked pipelines is then shared with the vendor, who checks the condition assessment tool’s applicability for the listed pipelines.




CoF PoF

Risk Score

Filter CI-AC Risk

Scores

Rank Scores

Select High

Ranked Risk Scores

Segments

Analyze

Figure 3-11: Selection of Pipes for Pilot Inspection Methodology




4. Inspection and Monitoring Strategies

Given the cost associated with many linear condition assessment techniques, it is important that the assessment of pressure pipes truly considers the combined risk of an asset, beginning with desktop assessment and progressing to more advanced methods of establishing condition where required. This progression should be driven by risk, material, observations, and the suspected deterioration process. This is illustrated in Table 4-1, demonstrating how the approach to condition assessment could scale with risk.

Table 4-1: Risk Driven Staged Approach to Condition Assessment

Evident from Table 4-1 is that only medium and high-risk assets may rationalize certain types of advanced condition assessment. The highest criticality assets must be managed proactively to avoid catastrophic failure. Doing so effectively requires an accurate understanding of the asset’s deterioration mechanisms, which can only be achieved through significant commitment of time and resources over its lifecycle. Low CoF watermains, however, are suggested to be monitored only given low, medium, and high LoF as the impact of a failure will not drastically impact the four risk parameters (economic, environmental, operational, and social). Therefore, it is suggested that such watermains be fixed upon failure as conducting advanced assessment will not be a cost-effective solution.

4.1 Retroactive Asset Failure Assessment and Root Cause Analysis Given the rate at which failures are observed, there are ample opportunities to establish the root cause of failures at reduced cost for low consequence assets (which occupy more than half of all watermain assets by length as depicted in Figure 5-1). For this reason, most of the pressurized pipe screening can occur as retroactive responses, coupled with other preliminary condition assessment screening exercises to establish system vulnerabilities. Maximizing information gained from failure will help the Municipality to understand the performance of a cohort, local vulnerability, and the driver of a failure mode. By maximizing the information gained from failures, the need for condition assessment can be managed by extrapolating observations when logical to do so. This also provides the most cost-effective opportunity to validate the results of desktop assessment techniques. Table 4-2 lists recommended attributes that should be collected in the event of a pipe failure.

HIGH Monitor Advanced Assessment Advanced Assessment

MEDIUM Monitor Advanced Assessment Advanced Assessment

LOW Monitor Desktop Analysis Desktop AnalysisLOW MEDIUM HIGH

LoF

Parameter/RankCoF




Table 4-2: Recommended Data Collection during Pressurized Pipe Failure by Material Type

Criteria/Material Ferrous Metals Thermoplastic Cement Investigations What are the characteristics of

internal and external pipe corrosion?

What soil units are present in the Municipality and how do they contribute to external corrosion?

What are other drivers of pipe failure (e.g., live traffic loads or road salt application)?

Are there instances of poor extrusion quality?

Can poor extrusion quality be tied to a manufacturer, era, geographic area of the Municipality, or design standard?

Are operating pressures driving pipe failure?

What PVC life funds are driving failures?

What types of defects drive failure (e.g., wire breaks vs. joint failures)?

What soil units are present in the corridor?

What are the design standards of cement pressure pipe?

Do designs match the resistivity requirements of the soil units?

Attribute/Data to Collect

Asset ID Date Age Material Diameter Pipe Class Road Class and AADT Design Standard Manufacturer Internal Lining (description) Internal Lining Thickness External Coating Internal Diameter (mm) Wall Thickness (mm) Joint Type Service Material External Maximum Pitting Depth External Average Pitting Depth External Pitting Surface Area External Pitting Material Loss External Pitting Rate External Maximum Wall

Penetration Internal Maximum Pitting Depth Internal Average Pitting Depth Internal Pitting Surface Area Internal Pitting Material Loss Internal Pitting Rate Internal Maximum Wall

Penetration

Asset ID Date Age Material Diameter Road Class and AADT Initial Wall Thickness Final Wall Thickness Operating Pressure Extrusion Quality (Laboratory

analysis) Dimension Ratio Design Standard Manufacturer Bed Class

Asset ID Date Age Material Diameter Road Class and AADT Wire Condition Joint Condition Design Standard Bed Class Manufacturer Soil Classification Soil Resistivity Soil Water Content Soil Resistivity Saturated Soil Redox Potential Soil Chlorides Soil Sulphides Soil pH

4.2 Polyvinyl Chloride The majority of PVC in the Municipality’s inventory was installed post 1975. This is significant as it suggests that most of the installed PVC was manufactured to an AWWA Standard (C900) as opposed to being ASTM Series pipe. A study by Moser and Kellogg (1994) found that ASTM Series pipe had twice the failure rate as pipe manufactured to the AWWA C900 Standard which was first released in 1975, largely attributed to an increased safety factor (i.e., 2.5 versus 2.0) and more robust quality assurance standards for production. Most PVC failures reported in the study were driven by defects produced by installation and were not deterioration related. Moser and Folkman (2008) noted that PVC pipe in pressure service has three independent life funds (Table 4-3). When the limits of either of these “funds” are exceeded, failure of the pipe is imminent.




Table 4-3: Life Funds of PVC Pipe

Life Fund #1: Sustained Pressure

Life Fund #2: Transient Pressure

Life Fund #3: Fatigue

Sustained pressure is seldom influenced by an external exposure environment, and generally relates to the original extrusion quality. Sustained pressure can be exacerbated by increased wall stress levels, and results in slow crack growth.

Transient pressure exploits the same aging vulnerability as sustained pressure (extrusion quality) but drives deterioration during brief instances of over pressure and under pressure, also known as water hammer. Over time, a pipe can become more vulnerable to short term over pressure due to deterioration driven by sustained pressure.

Fatigue drives PVC life funds when there is cyclic loading. While there will not be deformation during the process of cyclic loading (fatigue is unrelated to slow crack growth), the fatigue caused by this process can lead to failure.

Fatigue is often experienced in forcemains with constant speed pumps, although this should be understood as a pipe issue and not a distribution issue.

Provided that extrusion quality of the material is not deficient, the wall stresses are low, and the pipes are not subjected to cyclic loading, thermoplastic pipes often exhibit very subtle to non-existent deterioration processes and may last for very long time periods. In general, the focus of PVC condition assessment is extrusion quality sampling, coupled with continual monitoring of operating pressure. Table 4-4 summarizes the staged approach, which should focus on investigating extrusion quality unless evidence demonstrates that joint assembly issues are present.

Table 4-4: Assessment Levels for Pressurized PVC Pipe

Assessment Observations Assessment Technique Assessment Stage Cost Condition is Unknown Transient and Fatigue Analysis Desktop Analysis $

Slow Crack Growth Due to Applied Stress

Opportunistic or planned sampling and physical testing

Advanced Assessment $$

Slow Crack Growth Due to Poor Pipe Quality

Opportunistic or planned sampling and physical testing

Advanced Assessment $$

Poor Joint Assembly Leakage Detection Advanced Assessment $$$ Monitoring of extrusion quality will allow the Municipality to identify cohorts of pipes vulnerable to slow-crack growth. A categorization of risk exposure by pipe age, diameter ratio, manufacturer, and wall stress would serve as the basis for a rehabilitation plan. Generally speaking, replacements would only be rationalized in the face of wall stress in excess of extrusion quality driving failures well above the Municipality’s LOS thresholds. Risk exposure can typically be managed through management of operating pressure in a manner that reflects the sensitivity of PVC pipes with varying design criteria and extrusion quality. This monitoring approach is summarized in Table 4-5. Monitoring should begin by documenting the manufacturer and eras of construction of the Municipality’s thermoplastic pressurized mains and map the areas of the Municipality where these assets are situated. The asset level plan for thermoplastic opportunistic sampling should initiate the process of understanding the “life fund” vulnerabilities of each of these thermoplastic cohorts.

Table 4-5: Ramifications of Extrusion Quality and Applied Stress

Operating Pressure Wall Stress Vulnerability

psi kPA Dimension Ratio Psi MPa 60 414 18 510 3.5 Rare issues even with poor extrusion quality. 80 552 18 680 4.7

Very poor extrusion quality will drive active deterioration. 100 689 18 850 5.9 180 1241 18 1530 10.5 200 1379 18 1700 11.7 220 1517 18 1870 12.9 Moderately poor extrusion quality will drive active deterioration 240 1655 18 2040 14.1




4.3 Cast Iron and Ductile Iron The monitoring strategy for ferrous metal pipes such as DI and CI will predominantly focus on monitoring the observed process of corrosion in the system (if present) through root cause analysis of failures and screening of larger ferrous watermains (beginning with desktop assessment) when it is economically feasible to do so. For pipes where advanced condition assessment can be rationalized using risk analysis, Table 4-6 provides the staged approach to condition assessment for both internal and external corrosion assessment.

Table 4-6: Assessment Levels for Ferrous Pipes

Assessment Observations Assessment Stage Assessment Technique Cost Internal Corrosion: Unlined Pipes Desktop Analysis Transient and Air Handling Assessment $

Advanced Assessment Hydraulic Flow Tests $$ Internal Corrosion: Lining Failure Desktop Analysis CCTV $$$

External Corrosion Advanced Assessment Excavation and Non-destructive testing (random)

$$

Advanced Assessment Excavation and Non-destructive testing (targeted)

$$$

Advanced Assessment Leak detection $$$$ Advanced Assessment Pure pipe diver metallic platform $$$$$$$$$$ Advanced Assessment Continuous ultrasonic testing $$$$$$$$$$ Advanced Assessment Electromagnetic Remote Eddy Field

Current / MFL $$$$$$$$$$




5. Results

5.1 Consequence of Failure (CoF) Overall, it was found that approximately 7% of the water pipes by length (approximately 4 km) are classified as high CoF (refer to Figure 5-1); this percentage corresponds to about 6% of the total number of segments, as per Figure 5-2. By diameter, the [250 mm – 300 mm] cohort of watermains contained approximately 25% of the total cohort length (approximately 4 km) of high CoF while the [150 mm – 200 mm] cohort of watermains contained less than 0.5% of the total cohort length (see Figure 5-3). The smaller diameters did not contain any high CoF watermains. As per Figure 5-4, pipes composed of PVC occupied the greatest portion of high CoF pipes (approximately 6% of total length or about 3 km), while DI contained the second greatest portion of high CoF pipes (approximately 1% of the total length, or just under 1 km). Figure 5-5 shows the overall CoF distribution.

Figure 5-1: CoF Distribution by Length

Figure 5-2: CoF Distribution by Number of Segments




Figure 5-3: CoF by Diameter

Figure 5-4: CoF Distribution by Length and Material

Figure 5-5: Calculated CoF Distribution




5.2 Likelihood of Failure (LoF) Overall, it was found that approximately 7% of the water pipes by length (approximately 4 km) are classified as high LoF (refer to Figure 5-6); this percentage corresponds to about 5% of the total number of segments, as per Figure 5-7. By diameter, the [250 mm – 300 mm] cohort of watermains contained approximately 10% of the total cohort length (just under 2 km) of high LoF while the [150 mm - 200 mm] cohort of watermains contained about 5% of the total cohort length (approximately 2 km) (see Figure 5-8). The smaller diameters did not contain any high LoF watermains. As per Figure 5-9, pipes composed of PVC occupied the greatest portion of high LoF pipes (approximately 6% of total length or about 3 km), while DI contained the second greatest portion of high LoF pipes (less than 1% of the total length, or about 300 m). Figure 5-10 shows the overall LoF distribution following the methodology presented earlier.

Figure 5-6: LoF Distribution by Length

Figure 5-7: LoF Distribution by Number of Segments




Figure 5-8: LoF Distribution by Diameter

Figure 5-9: LoF Distribution by Material and Length

Figure 5-10: LoF Distribution

0

200

400

600

800

1000

1200

1400

1600

0-10 10-20 >20

Fre

qu

en

cy

LoF Range

LoF Distribution




5.3 Overall Risk Overall, it was found that approximately 8% of the water pipes by length (approximately 4 km) are classified as high risk (refer to Figure 5-11); this percentage corresponds to about 5% of the total number of segments, as per Figure 5-12. By diameter, the [250 mm – 300 mm] cohort of watermains contained approximately 22% of the total cohort length (approximately 3 km) of high risk while the [150 mm- 200 mm] cohort of watermains contained about 2% of the total cohort length (approximately 1 km; see Figure 5-13). The other diameter cohorts did not contain any high risk watermains. As per Figure 5-14, pipes composed of PVC occupied the greatest portion of high-risk pipes (approximately 8% of total length or about 4 km). Figure 5-15 shows the overall risk distribution following the methodology presented earlier.

Figure 5-11: Risk Distribution by Length

Figure 5-12: Risk Distribution by Number of Segments




Figure 5-13: Risk Distribution by Diameter

Figure 5-14: Risk Distribution by Material and Length

Figure 5-15: Risk Score Distribution

78.5%

19.3%2.2%

150 mm-200 mm

Low

Medium

High

50.34%27.98%

21.68%

250 mm-300 mm

Low

Medium

High




Figure 5-16: Risk Scatter Plot

5.4 Pipelines Suggested for Pilot Inspection Of the total length of AC and CI pipelines (2.4 km), most of the pipelines are made of AC. After implementing the risk-based analysis on these watermains, the risk scores for each is calculated and ranked accordingly. The results, shown in Figure 5-17, illustrate that the majority of AC and CI pipelines are categorized as Medium Risk. By length, AC pipelines that are in low and medium Risk are approximately 200 m and 1 km, respectively. However, the total length of CI pipelines that are in the low Risk category is about 90 m and the total length of the same material in the medium Risk category is approximately 700 m.

Figure 5-17: Risk Categories by Total Length of AC and CI The results of the sorted Risk Scores for AC and CI pipelines are listed in Table 5-1. The table provides the Object ID, material type, length, and the corresponding calculated score. This list will be provided to the vendor as an initial guidance to perform the condition assessment. The actual implementation of the condition assessment will be based on the site condition and the applicability of the tool to reduce costs related to enabling work.




Table 5-1: Ranked AC & CI Pipelines Based on Risk Scores

OBJECTID Material Length (m) Risk Score

2850 CI 376.63 547.81 2855 CI 2.30 517.67 2895 CI 2.30 517.67 2851 CI 120.61 481.29 2857 CI 229.12 481.29 2852 CI 6.84 481.29 2433 AC 115.33 145.48 2453 AC 98.25 145.48 2437 AC 2.72 133.42 2438 AC 1.46 133.42 2447 AC 0.96 133.42 2448 AC 1.39 133.42 2454 AC 1.56 133.42 2455 AC 2.29 133.42 2435 AC 4.57 124.04 2436 AC 17.28 124.04 2446 AC 259.65 124.04 2456 AC 17.05 124.04 2457 AC 3.46 124.04 2459 AC 358.47 124.04 2460 AC 218.36 124.04 2358 AC 55.40 76.93 2361 AC 3.29 76.93 2359 AC 2.24 70.56 2357 AC 244.98 86.00 2362 AC 19.50 65.60 2363 AC 14.65 65.60 2392 AC 191.58 65.60 3098 CI 2.06 13.46 3096 CI 1.82 13.46 3079 CI 2.54 12.06

5.5 Inspection and Monitoring Strategy The inspection and monitoring matrix established (refer to Table 4-1) is used as a guidance to choose the proper condition assessment approach. The staged approach is dependent on the results of the LoF and CoF in which Monitor, Desktop Analysis, and Advanced Assessment is selected. Table 5-2 shows the results attained after matching the parameters into the matrix classification. The numbers provided in the table represent the number of segments. For example, the number of segments classified as medium CoF and low LoF is 186. Based on the matrix, these segments are recommended to be assessed using Desktop Analysis.

Table 5-2: Staged Approach Assessment Matrix Results (Number of Watermain Segments)

LoF HIGH 71 9 1

MEDIUM 251 35 18 LOW 885 186 67

Parameter/Rank LOW MEDIUM HIGH CoF




Table 5-3, provides information about the total length of pipeline materials that needs to be monitored or evaluated, using desktop analysis or advanced assessment based on the developed model. The results suggest that about 4 km of pipelines are suggested to be evaluated using advanced assessment. The majority of this category consists of PVC pipelines with a total length of 3.45 km. With regard to pipelines suggested for desktop analysis, PVC pipelines have the highest total length of the 11.35 km.

Table 5-3: Total Length of Staged Approach to Condition Assessment by Material

Pipe Material Monitor, Length (m)

Desktop Analysis, Length (m)

Advanced Assessment, Length (m)

PVC 26,969 9,174 3,451 POLY 5 - - HDPE - 151 -

AC 1,634 - - CI 747 - - DI 12,993 2,020 612 CU 16 - -

Total 42,364 11,345 4,063 Percentage of Length 73.33% 19.64% 7.03%




6. Summary, Conclusions and Recommendations

6.1 Summary and Conclusions Water networks are a critical component in any urban city. As buried infrastructure, it is out of sight and most often neglected. In addition, budget allocation constraints can sometimes impact a Municipality’s ability to maintain the entire network. Therefore, constructing reliable models that provide systematic approaches in prioritizing watermains for condition assessment, maintenance, and rehabilitation, is essential to ensure a proactive approach to asset management is applied throughout the design-life of watermains. The main objective of this TM is to design a reliable risk-assessment model to attain robust prioritization conclusions for the Municipality of Thames Centre. The model is expected to be implemented by the Municipality’s staff to prioritize watermain segments for assessment and renewal interventions. The main objective is accomplished after considering the following:

◼ Industry Practice: A summary of existing practices toward infrastructure risk assessment is provided along with their generic models’ methodologies.

◼ Consequence of Failure: A CoF model was designed based on four main categories, which are economic, social, environmental, and operational factors. The overall methodology of the CoF model relied on a hierarchy of factors and sub-factors that are aggregated to calculate a CoF index for each watermain.

◼ Likelihood of Failure: A LoF model was established based on the cumulative density function (cdf) curve using the Weibull distribution analysis. The Estimated Service Life (ESL) and age parameters were considered for the implementation of this methodology as well as watermain breaks for some of the pipelines.

◼ Risk Model: A risk score is computed considering the product equation of the CoF and LoF, which is later used to prioritize watermains

Based on these objectives, the results attained pertinent to risk calculations are as follows:

CoF Model:

1. The total length of watermains in high CoF is approximately 4 km 2. The pipe material that occupied the greatest high CoF portion is PVC

LoF Model:

1. The total length of watermains in high LoF is approximately 4 km 2. The pipe material that occupied the greatest high LoF is PVC, based on observed breakages.

Risk Model:

1. The total length of watermains in high risk is approximately 4 km 2. The pipe material that occupied the greatest high risk is PVC




Based on the suggested staged approach toward condition assessment, PVC acquired most of the advanced assessment category. Following this risk assessment model, a reliable condition assessment plan and recommended assessment methods will be established in subsequent project reports. This approach will enable the Municipality to overcome future budget constraints by assessing/renewing assets on a prioritization framework.

6.2 Recommendations Based on the task outcomes, AECOM submits the following recommendations:

1. It is recommended that condition assessment inspections be performed on CI and AC pipelines that have high risk scores. However, it should be noted that the actual selection mechanism is subject to site condition as some tools have maximum length constraints. Therefore, to optimize the provisional budget, some of the highly ranked pipelines may be delayed, for the next provisional budget, due to site or tool limitations. If the Municipality opts to inspect these pipelines, some enabling work will be required such as potholes. In this case, all enabling work costs will be deducted from the provisional budget. As the main intention is to maximize the pilot inspection length, the delayed pipelines could be prioritized for inspection during the next provisional item;

2. It is recommended that all other material types also be scheduled for condition assessment – not just AC and CI. Where applicable, DI pipelines close to AC-CI inspection areas are suggested to be tested. As a result, the decision of selecting a cost-effective tool will also rely on its applicability on different material types. A comprehensive methodology will be prepared in TM#3 that shows the optimal tool to be chosen for inspection;

3. It is recommended that high risk pipelines that require minimal to no enabling work are selected for condition assessment to maximize the utilization of the provisional budget ($30,000) in performing the inspection pilot. If an inspection tool requires enabling work to perform the inspection, the total inspection length will be reduced to cover the expenses of enabling work;

4. It is recommended comprehensive failure data be collected so that they can later be used as a baseline for any statistical model. Prediction models provide opportunity for the Municipality to anticipate future failure of watermain breaks. Regular update of this information in the GIS is also important;

5. It is recommended to perform root cause analysis on the extracted coupons of all watermain breakages to understand the exact causes of failure rather than relying on visual observations;

6. It is recommended to review the as-built drawings for PVC pipelines from cohorts known to exhibit breakage and vulnerability to check the installation and the constructability specifications utilized (e.g., design standards, bedding class, installation method). It is recommended to perform coupon sampling and applied load analysis along with geotechnical investigation to have more information about the causes of the breakage in the Dorchester area. The findings could conclude whether replacements are required.

7. It is recommended to conduct geotechnical investigations to ensure that soil characteristics are noncorrosive as expected. Corrosive soil can expedite the failure mechanism in ferrous materials and therefore will impact any preliminary LoF estimation.




7. References

ISO31000, 2009: Risk management – Principles and guidelines, p. 2. ISO.

AWWA, 2010: AWWA J100-10 Risk Analysis and Management for Critical Asset Protection (RAMCAPÂ®) Standard for Risk and Resilience Management of Water and Wastewater Systems. US: American Water Works Assn.

Canadian Water and Wastewater Association, 2005: Canadian Guidance for Managing Drinking-Water Systems: A Risk Assessment/Risk Management Approach. CWWA.

Moser, & Folkman, 2008: Buried Pipe Design, Third Edition. McGraw-Hill.

Moser, A. P., & Kellogg, K. G., 1994: Evaluation of polyvinyl chloride (PVC) pipe performance. Foundation and American Water Works Association.

Muhlbauer, W. K., 2004: Pipeline risk management manual. Burlington, Ont: Gulf Professional Publishing.

Statistics Canada, G. O., 2017, November 29: Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province]. Retrieved October 2018, from https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539027&Geo2=PR&Code2=35&Data=Count&SearchText=Thames%20Centre&SearchType=Begins&SearchPR=01&B1=All&GeoLevel=PR&GeoCode=3539027&TABID=1


Appendix A Workshop #1 – Risk Findings and Calibration: Minutes of Meeting


Minutes The Municipality of Thames Centre – Water System Asset Inventory Workshop #1 – Risk Model

Ref Action Initial 01 Opening Remarks/Safety Minutes

- DO started the meeting and shared a safety minute before MS started the presentation

- Please refer to attached presentation “PRE-2018-12-13_Wkshp1-Risk Model_60586191_V3” for presentation materials.

02 Project Overview & Session Objectives (Slides 5-6) - The objectives of the workshop were shared as

follows:

To understand the consequence of failure (CoF), likelihood of failure (LoF), and risk parameters in watermain networks

To discuss the preliminary findings of the proposed risk model

To review the proposed model and calibrate some scores or weights, if required

To discuss next steps and future milestones

03 Understanding Risk Parameters (Slides 7-12) - MS discussed the types of failure that water

networks may be subjected to. - MS also presented the definition of the LoF and

CoF and showed some examples of each - An example of Region of Halton – Valve

Maintenance Planning was shared and MS discussed its importance in incorporating the risk parameters into a decision-based matrix. In that project, a GIS based system was used to highlight the criticality of the assets

Minutes

Meeting name Workshop #1 – Risk Model

Subject Risk Model

Attendees Municipality of Thames Centre: Carlos Reyes (CR), Meghan Fletcher (MF), Kevin Willson (KW), Jeff Carsey (JC), Jarrod Craven (JRC), Ron Lewis (RL) AECOM: David O’Gorman (DO), Michele Samuels (MS), Erik Wright (EW), Khalid Kaddoura (KK)

Meeting Date December 13, 2018

Time 11:30 AM (EST)



Prepared by KK/MS




Ref Action Initial 04 Criticality Model Review (Slides 13-17)

- MS shared the methodology carried-out in establishing a risk model. The first step towards an effective risk model development is the review of the inventory of the water network. Next, CoF and LoF models were prepared to calculate the risk scores for each asset. Doing so aided AECOM to prioritize pipelines for inspection.

- The criteria considered were economical, operational, social, and environmental factors. Under each category, some sub-factors were considered and handed-out to the client (attached). The figure shows the hierarchy of factors and sub-factors along with scores and weights. No calibration on the CoF weights and scores were required as these were agreed by the Municipality.

- The sensitive area considered under the Environmental group is described by Well-head as well as the Group C – Environmental Area

- Business areas were pointed out and required to be adjusted in the GIS model and database.

- The Municipality stated that they observed some solid rocks at the same location of PVC breaks.

- The Municipality stated that PVC breaks occurred in specific sample where pipelines are made of thin wall material.

- The Municipality suspects that PVC breaks were a result of the improper backfilling process and material

- The Municipality stated that at the downstream and upstream of PVC breaks, some longitudinal cracks were observed.

- Ductile Iron (DI) pipelines do not have any cathodic protection, as claimed by the Municipality.

- The Municipality confirmed that the soil is non-corrosive and old DI extracted coupons did not experience any corrosion in the interior and exterior surfaces.

The Municipality will send to AECOM the classification of zoning within the boundaries of Dorchester and Thorndale in a GIS format, if available.

AECOM will adjust the scores of some pipelines that correspond to the Business area.

AECOM to consider the breaks historical data in the calculation of the LoF, mainly in PVC pipes

The Municipality will send more information to AECOM about the DR material of PVC pipelines.

AECOM to review the estimated service life (ESL) of the DI pipelines and update LoF, if necessary.

CR

EW/KK

KK

CR

KK

05 Condition Assessment Methodology (Slides 18-20) - The methodology that was considered in prioritizing

and selecting the pilot inspection was presented

06 Preliminary Condition Assessment Matrix (Slides 21-23)

- The preliminary condition assessment strategy was presented, which was based on three different decision variables:

o Monitor o Desktop analysis o Advanced assessment



Ref Action Initial 07 Next Steps (Slides 24-26)

- The tentative schedule going forward was shared with the Municipality (Slide 25).

- MS suggested that Task 7 can be implemented after performing Task 8: Provisional CA Inspection, if the Municipality is interested in completing Task 8.

AECOM to submit cost proposal for PVC design and provide budgetary cost estimate for inspecting existing PVC pipelines.

DO


Thames Center & AECOMWorkshop #1 – Risk ModelWatermain Condition Assessment and Inventory

13/12/2018

1

Water Condition Assessment and Inventory CastIron Replacement NeedsWorkshop #1 – Criticality ModelMunicipality of Thames Centre

David O’Gorman - Project Manager

Michele Samuels, M.Eng., MBA, P.Eng. – Senior Asset Management Consultant

Khalid Kaddoura, PhD, PMP, EIT – Intermediate Asset Management Consultant

Erik Wright – GIS Specialist

December 13, 2018

1. Introductions & Safety Minute

2. Project Overview & Session Objectives

3. Understanding Risk Parameters

4. Consequence of Failure Framework Reviewo Model Calibration (if needed)

5. Condition Assessment Pilot Methodology

6. Preliminary Condition Assessment Matrix

7. Q&A

Agenda

Page 2



13/12/2018

2

Introduction & Safety Minute

Safety Minute – Basement Flooding

While a flood in your basement may prompt you to rushdownstairs for belongings, your safety should be theultimate priority.

– When your basement is wet, there is a legitimate risk ofelectrical shock. Do not enter if you suspect water hasrisen to outlets, heaters, baseboards, furnaces, etc.

– Evacuate immediately if you detect a rotten egg smell ofgas.

– Call your local utility company’s emergency hotline.

– Only turn off your main breaker if you are positive it issafe to do so.

Page 4



13/12/2018

3

Project Overview & SessionObjectives

Session Objectives

Page 6

Understand

CoF, LoF, Riskparameters in

water networks

Discuss

Preliminaryfindings of

proposed model

Review

Calibrate model ifrequired

Next Steps

Discussmilestones



13/12/2018

4

Understanding RiskParameters

What Constitutes Water Failure?

Page 8

Breaks: from pinholes to major leaks andtotal failures

Capacity issues

Failure of appurtenances: valve, airvalves and hydrants

PRV - overpressure or no water



13/12/2018

5

What is Asset Criticality?

RISK = Probability x Consequence of Failure

How severe are theconsequences of asset

failure?How likely is it for the

asset to fail? Page 9

Consequence

How severe are theconsequences of assetfailure?

How likely is it for theasset to fail?

Probability

Page 10



13/12/2018

6

Consequence

How severe are theconsequences of assetfailure?

How likely is it for theasset to fail?

Probability

* City of Calgary McKnight Boulevard Feedermain failurePage 11

Sample Uses of Asset Criticality:Region of Halton - Valve Maintenance Planning

Page 12

GIS - Mains



13/12/2018

7

Criticality Model Review

Overall Methodology for Pipe Selection

Page 14

InventoryProfile andReview ofIndustry

Standards

DevelopConsequence

of FailureFramework

PreliminaryRisk Model

Output

Condition Assessment Plan Overview PrioritizedList for Inspection

DevelopLikelihood of

FailureFramework



13/12/2018

8

Criticality Framework – What Does it Look Like?

Asset Criticality

Economic

Operational

Social

Environmental

Impact on the community & has acommunity and a political aspect

Impact on the natural resourcesand environment

Financial impact on themunicipality & its stakeholders

Impact on operational ability

If the asset fails, how severe are the impacts on the following spheres of influence?

Page 15

CoF Factors & Sub-factors

Page 16

Economic

DiameterMaterial

Land UseAccessibility

Environmental

DiameterWater Body

Sensitive Area

Social

Land UseDiameter

Road Classes

Operational

DiameterPipe type

Tracing Wire



13/12/2018

9

Preliminary Model

Page 17

Diameter (mm) Attribute value50 10

100 30150 50200 65250 80300 100

Material Attribute value

PVC 100DI 25

HDPE 75AC 50CI 50CU 25

POLY 100

Land Use Attribute valueOP - Residential 50OP - Urban Area Boundary 25OP - SPAs 50OP - Industrial - Settlement 50OP - Dorchester - Commercial - General 100OP - Institutional 75OP - Dorchester - Parks & OS 100OP - Group B - Protection Area 50OP - WHPA_SCHED_A 75OP - Group C - Environmental Area 75OP - WHPA_DORCHESTER 100

Economic

15%

20%

30%

Accessibility Attribute valueBridge 100

Railroad 100

35%

25%


Pipe Type Attribute valueWatermain 75

Hydrant Lead 100Operational

50%

25%

25%

35%

Land Use Attribute valueOP - Residential 50OP - Urban Area Boundary 25OP - SPAs 50OP - Industrial - Settlement 50OP - Dorchester - Commercial - General 100OP - Institutional 75OP - Dorchester - Parks & OS 100OP - Group B - Protection Area 50OP - WHPA_SCHED_A 75OP - Group C - Environmental Area 75OP - WHPA_DORCHESTER 100


Road Class Attribute valueA1 100A2 100A3 100B1 75B2 75B3 50C1 25C2 25C3 25

NONE 0

Social

20%

50%

25%

25%


Water Body Attribute valueYes 100No 0 Sensitive Area Attribute value

Yes 100No 0

Environment

20%20%

20%

60%

Tracing Wire Attribute valueYes 0No 100

Condition Assessment PilotMethodology



13/12/2018

10

CoF Preliminary Results (Dashboard)

Page 19

Apply LoF

AC & CI HighCoF = 0%

Apply Risk

• 16% High• 61% Medium• 23% Low

Selected highestscoring segments forpreliminary inspection

Added value toinspect DI segment

CoF/Risk Preliminary Results (Maps)

Page 20

Dorchester – Risk FactorDorchester – CoF

Thorndale– Risk FactorThorndale– CoF



13/12/2018

11

Preliminary ConditionAssessment Matrix

Influence of Asset Criticality on Condition AssessmentStrategy

Page 22

• Monitor: monitor the deterioration modelbased on asset age; No immediateinspection plan

• Desktop Analysis: fatigue, transient,hydraulic modeling, applied load analysis,etc.

• Advanced Assessment: in situinspection technologies




LoF

Parameter/RankCoF



13/12/2018

12

Preliminary Condition Assessment Decision MatrixResults

Page 23




LoF

Parameter/RankCoF

Pipe Material Monitor Desktop Analysis Advanced Assessment

PVC 26,471 13,123 -

POLY 5 - -

HDPE - 151 -AC 1,634 - -CI 366 4 377DI 12,635 245 2,745CU 16 - -

Total 41,128 m 13,523 m 3,122 m

Next Steps



13/12/2018

13

Next Steps

Page 25

Task Notes2 Asset Inventory TM#1 Submitted

3 Risk AnalysisTM#2 Draft to beupdated/finalized after workshop– ETA January 11, 2019

4 Condition Assessment (CA) TM#3 Submitted

5Inspection - Leak Detection andCondition Assessment

Awaiting technical inspectionreport

6Determine Level of Service for AssetSystem

Schedule workshop – January2019

7Analysis of Life Cycle andReplacement Costs Assets ETA – February 2019

8 AC & CI Inspection TBD – Provisional Item

Questions?


Appendix BCoF, PoF, and Risk Maps - Dorchester and Thorndale










aecom.com



Technical Memorandum #3: Condition Assessment Plan and Recommended Assessment Methods

Prepared by:


Date: January, 2020

Project #: 60586191


Distribution List



Revision History

Revision # Date Details Name Position 1 Initial Draft Khalid Kaddoura Asset Management Consultant 2 QA Review Rabia Mady Technical Lead 3 Draft Submission David O’Gorman Project Manager 4 Final Submission Michele Samuels Project Manager


AECOM The Municipality of Thames Centre Technical Memorandum #3: Condition Assessment Plan and Recommended Assessment Methods

TM3_2020-01-30_Condition Assessment Plan & Recommended Assessment Methods_60586191_V4.Docx


















Authors

Report Prepared By:

Khalid Kaddoura, PhD, PMP

Report Verified By:

for

Rabia Mady, P.Eng (no longer employed by AECOM)

Report Approved By:

Michele Samuels, M.Eng., MBA, P.Eng.

Project Manager





1. Introduction ....................................................................................... 1



2. Condition Assessment Approach for Asbestos Cement (AC) & Cast Iron (CI) Pipelines...................................................................... 3

2.1 Desktop Condition Assessment Methods ................................................................ 3

2.2 Field-based Condition Assessment Methods .......................................................... 4

2.2.1 Destructive vs. Non-Destructive Testing ................................................................. 4

2.2.2 Visual Inspection .................................................................................................... 5

2.2.3 Leaks and Trapped Air Detection ........................................................................... 6 2.2.3.1 External Leak Devices...................................................................................... 7 2.2.3.2 Internal Leak Devices ....................................................................................... 7

2.2.4 Remaining Wall Thickness Measurement ............................................................... 7

3. Inspection Tools ................................................................................ 8

3.1 Nautilus Free-Swimming Leak Detection Tool ........................................................ 8

3.2 ePulse® – Acoustic Wave Propagation (AWP) Pipe Wall Assessment & Leak Detection Tool ......................................................................................................... 8

3.3 Sahara Technology Leak Detection and visual Tool ............................................. 10

3.4 SmartBall® Technology Leak Detection Tool ......................................................... 11

3.5 Investigator+TM Leak Detection and visual Tool .................................................... 12

3.6 Remote Field-Testing Technology (RFT) – SeeSnake Pipe Wall Assessment ..... 12

3.7 p-CAT™ Technology Pipe Wall Assessment ........................................................ 14

4. Technology Evaluation Desktop Analysis ...................................... 15

4.1 Evaluation Criteria ................................................................................................. 15

4.2 Criteria Scoring and Evaluation ............................................................................. 16

4.2.1 Criteria 1: Inspection Risk ..................................................................................... 16

4.2.2 Direct Cost ........................................................................................................... 16 4.2.2.1 Analysis and Scoring ...................................................................................... 17

4.2.3 Impact to the Operation of the Distribution Network .............................................. 18

4.2.4 Accuracy of Results .............................................................................................. 18

4.2.4.1 Analysis and Scoring – Accuracy: Leak Detection .......................................... 19 4.2.4.2 Analysis and Scoring – Measuring Remaining Wall Thickness ........................ 19

4.2.5 Resolution of Results ........................................................................................... 20 4.2.5.1 Analysis and Scoring – Identifying Leak Size .................................................. 20 4.2.5.2 Analysis and Scoring – Measuring Remaining Wall Thickness ........................ 21

4.2.6 Applicability on Different Material Types ............................................................... 22




4.3 Criteria Relative Importance Weights .................................................................... 22

4.4 Technology Ranking.............................................................................................. 22


5.1 Conclusions ........................................................................................................... 24


6. Bibliography .................................................................................... 26

List of Figures Figure 2-1. Properties Determined from Destructive and Non-Destructive Testing ................................................... 4 Figure 2-2: Major Challenges for Non-Destructive testing for Pipelines in and out of Service ............................... 5 Figure 2-3: Pure Technology Ltd. Robotics platform (with and without specialized equipment) ............................ 5 Figure 2-4: MAT Pipe-Inspector® (Leak detection tool combined with visual capability) ........................................ 6 Figure 2-5: Acoustic Leak Detection Technology ................................................................................................ 6 Figure 3-1: Nautilus Acoustic Ball ....................................................................................................................... 8 Figure 3-2: ePulse® AWP Pipe Wall Assessment ............................................................................................... 9 Figure 3-3: ePulse Typical Measurement Setup .................................................................................................. 9 Figure 3-4: ePulse Inspection Tool ................................................................................................................... 10 Figure 3-5: Sahara System Configuration ......................................................................................................... 10 Figure 3-6: The SmartBall® System ................................................................................................................. 11 Figure 3-7: The Investigator+TM ........................................................................................................................ 12 Figure 3-8: SeeSnake RFT Tool ....................................................................................................................... 13 Figure 3-9: Pressure Wave Station ................................................................................................................... 14 Figure 3-10: Collecting Sensor ........................................................................................................................... 14

List of Tables Table 4-1: Summary of Inspection Tools Analyzed .......................................................................................... 15 Table 4-2: Scoring Protocol - Consequence of Technology Platform Failure (CoTPF) ...................................... 16 Table 4-3: Scoring Protocol – Direct Cost ........................................................................................................ 17 Table 4-4: Scoring Protocol – Impact to the Operation of the Distribution Network ........................................... 18 Table 4-5: Scoring Protocol – Accuracy of Results (Leak Detection) ................................................................ 19 Table 4-6: Scoring Protocol – Accuracy of results (Measuring Remaining Wall Thickness)............................... 20 Table 4-7: Scoring Protocol – Resolution of Results (Identifying Leak Size) ..................................................... 20 Table 4-8: Scoring Protocol – Resolution of Results (Measuring Remaining Wall Thickness) ........................... 21 Table 4-9: Scoring Protocol – Applicability on Different Material Types ............................................................ 22 Table 4-10: Criteria Weights .............................................................................................................................. 22 Table 4-11: Technology Ranking ....................................................................................................................... 23



TM3_2020-01-30_Condition Assessment Plan & Recommended Assessment Methods_60586191_V4.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 59.6 km of watermain infrastructure (1.8 km of watermains are privately owned) to supply water and provide management services to a population of 13,191 residents (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2 (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). Unlike wastewater and/or stormwater collection systems, pressurized watermains are often operationally and cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing them in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF), and can present significant risks on the event of an unexpected failure. Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess water distribution networks. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition, assess failure risk, and estimate residual design life in watermains’ infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing the inspections to minimize the risk exposure while optimizing budgetary allowances. On this basis, the pressurized watermains can be managed preventatively, through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of the assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based State of Good Repair (SOGR) program to:

1. Prioritize and assess watermains 2. Analyze pipe life cycle 3. Provide an annual funding forecast

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with the procedures and tools to prioritize watermains for inspections and prioritize these inspected watermains for renewal in the short-, mid-, and long-term.




The primary objective of this study is to develop a State of Good Repair (SOGR) schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-objectives including, but not limited to, the following:

1. Reviewing inventory data; 2. Identifying failure modes and distress indicators; 3. Developing CoF model and prioritizing pipes for assessment; 4. Matching suitable technologies and planning for a pipeline condition assessment pilot [Cast Iron (CI)

and Asbestos Cement (AC) pipes only] for critical watermains previously identified by the risk model; 5. Interpreting pilot inspection findings to estimate the likelihood of failure (LoF); 6. Defining the level of service; and 7. Building a comprehensive risk-based decision matrix tree for pipe interventions actions.

1.2 Objectives for Technical Memorandum #3 Although the Municipality’s pipe inventory includes different pipe materials such as cementitious, non-ferrous and ferrous metals, and thermoplastic pipelines, Tech Memo (TM) #3 is designed to provide valuable information about the condition assessment tools that are suitable to assess CI and/or AC pipelines as per the Municipality’s requirement in the Request for Proposal (RFP) stage. Therefore, the list of points to be covered in this TM are as follows:

1. Provide an overview of available technologies to assess AC & CI Pipelines; 2. Screen technologies and platforms suitable for inspecting small pipe diameters (≤ 300 mm); 3. Evaluate and score technologies; and 4. Conclude the recommended technology to be used in the assessment of AC & CI critical pipe

segments.




2. Condition Assessment Approach for Asbestos Cement (AC) & Cast Iron (CI) Pipelines

To complete a comprehensive technology selection process for assessing small diameter (≤ 300 mm) watermains made of AC and CI, a considerable understanding of deterioration drivers is necessary, as detailed in Technical Memorandum #1: Inventory Review and System Characteristics. Furthermore, the discussion for condition assessment technologies will begin with outlining the basic methodologies within desktop condition models and then identify available technologies for field-based watermain condition assessment.

2.1 Desktop Condition Assessment Methods Condition assessment of pressurized pipes should commence with Desktop Condition Assessment exercises in the form of either simplified or more complex model development. These models can form the basis for more advanced models and facilitate the development of a formal, quantitative process to rationalize the most appropriate amount, timing, and methods for re-investment of capital. The ability to understand and predict the remaining operational life of a pipeline obviously plays a very significant role in developing this formal quantitative process. The work of De Silva et al. (2002) on CI and AC pipelines in Australia provides a useful overview of the role that understanding a pipeline’s condition plays in bridging the gap between reasonable concerns and the primary objectives of a sound network management strategy for pressure pipes. While developed for water networks, the authors’ work and observations are directly analogous to many of the challenges facing the assessment of watermain networks. In the work of De Silva et al. (2002), the authors strongly promote the use of deterministic as opposed to probabilistic methods for the development of an appropriate management model for water distribution infrastructure. An appropriate approach for most large networks usually involves a balance of both probabilistic and deterministic methods. Rajani and Kleiner of the National Research Council (NRC) of Canada have extensively studied both probabilistic and deterministic models and published some of the most foremost research on deterministic models for CI infrastructure (Rajani & Kleiner, 2001). In fact, their research and modelling approach is referenced, in the work by De Silva et al. (2002), as a best-practice for a deterministic model for CI pipes to be used in water network management in Australia. However, deterministic models require a considerable understanding of the pipe’s existing physical condition to estimate the remaining service life or Likelihood of Failure (LoF) with a high degree of certainty. The cost of acquiring this information must be carefully weighed against the predictive accuracy required and achieved, and the failure costs being mitigated. In any case, creating an advanced desktop model is best supported once there is a more thorough understanding of the pipe environment and actual deterioration drivers. There are typically connections between modes of failure and either the surrounding environment the pipe is subjected to, the applied loads the pipe sees, or some combination of the two. Therefore, while condition analysis initially commences as a desktop model, it is greatly enhanced by the securing of true physical condition observations either through point observations or continuous measurement tools. The reliable outputs resulting from inspection surveys may aid in establishing robust predictive




and desktop condition assessment models that can minimize future inspection costs. Besides, better deterioration models can be designed and incorporated in several optimization tools to plan for renewal interventions.

2.2 Field-based Condition Assessment Methods Field-based condition assessment of pressurized pipe networks is a complex process for a variety of reasons ranging from system operation requirements to enable inspection, to the complexity of the deterioration process and/or the selection of a suitable technology to measure the deterioration directly or indirectly. The complexity is further exacerbated by some economic considerations since technologies yielding higher assessment accuracy are usually associated with higher costs. Therefore, this memorandum aims to analyze some available condition assessment technologies and the various field condition assessment methods that best suit the goals of this study to assess CI and AC pipelines.

2.2.1 Destructive vs. Non-Destructive Testing

Destructive testing methods typically involve techniques which alter the pipe specimen in such a way that it is no longer deemed suitable for service. Non-Destructive testing (NDT), also known as non-destructive evaluation (NDE), can be defined as a test or method that yields information about the pipe in-situ, without affecting the serviceability of the pipeline. A comparison between the two methods shows that each yield subtly different yet valuable information with which to infer condition, deterioration, and remaining service life. Figure 2-1 provides a basic list of a few properties that can be gathered through each method.

Figure 2-1. Properties Determined from Destructive and Non-Destructive Testing NDE techniques have been developed to permit both rapid and qualitative inspection and condition assessment of various materials from their external surface and beyond. They are proactive in nature, and can be used in different platforms to accommodate the operating status of the system during inspection (in-service or out of service), and provide the opportunity to plan repairs and prevent failures. Not all NDE can be deployed without system shutdown. Having a large suite of tools and technologies that can inspect pipelines in-service or out of service presents a major challenge for inspection planning. Figure 2-2 provides a basic list of a few of the operational challenges that need to be addressed in NDE planning stages for pipelines in-service or out of service.

• Strength • Hardness • Corrosion characteristics and cause • Remaining wall thickness • Coating conditions

Destructive

• Leaks and air pockets • Cracks and fractures • Remaining wall thickness • Corrosion characteristics • Wire breaks in prestressed concrete

cylinder pipe (PCCP) • Soil/groundwater chemical

composition and electrical properties

NDE




Figure 2-2: Major Challenges for Non-Destructive testing for Pipelines in and out of Service Destructive testing, which can be either a reactive/opportunistic investigation or a planned investigation, involves physical examination of pipe sections generally taking place in a laboratory. Typically, this type of testing is performed on specimens collected when repairs and upgrades are performed on existing pipelines. Sampling can provide insights to valuable information including:

◼ Remaining wall thickness; ◼ Relevant mechanical properties for structural assessments; ◼ Integrity of coatings and linings; ◼ Type and extent of corrosion of the pipe material; and ◼ Soil corrosivity, by way of chemical/electrochemical analysis of the soil surrounding the pipe (e.g.,

resistivity, soluble ion concentrations, pH, etc.).

2.2.2 Visual Inspection

Visual inspection is considered a NDE assessment method that may be conducted externally at isolated excavations, or internally for larger diameter pipes via confined entry. Visual inspections based on CCTV, allows the internal surfaces of the pipe wall to be inspected for defects. The information obtained is limited to surface defects and resolution of results is only as good as the equipment used. Visual inspections can be enhanced by the use of specialized equipment to obtain a more in-depth assessment of the pipe’s condition at a particular location. Commonly used equipment include laser-based pipe surface profiling tools mounted on a CCTV robotic platform, which may help to identify early detection of deterioration caused by corrosion or other degradation factors (Figure 2-3).

Figure 2-3: Pure Technology Ltd. Robotics platform (with and without specialized equipment)

In-service

• Availability of access points and clearances for insertion/extraction tools • Mechanical modifications to enable inspection. • Temporary system shutdown to enable tool launch and retrieval • Flow velocity conditions • The ability to traverse in-line features • Status of any connecting pipes during inspection

Out of Service

• Availability of dewatering pipelines • Air ventilation and Air Release Valve (ARV) functionality• Confined space entry hazards• Passing obstacles along the pipeline• Rescue team as part of H&S plan• Overall impact to the pumping station service area

Without specialized equipment

With specialized equipment




As mentioned before, visual inspections cannot provide any quantitative information of the structural condition of the pipe. However, technology vendors have recently began adding CCTV capability to leak detection equipment to enable observations of leaks and trapped air in addition to coating conditions that can be detected by CCTV equipment (Figure 2-4).

Figure 2-4: MAT Pipe-Inspector® (Leak detection tool combined with visual capability)

2.2.3 Leaks and Trapped Air Detection

One of the most efficient condition assessment methods is done through leaks and trapped air detection. Escaping air or liquids create an acoustic signal as they pass through a hole in the pipe. Acoustic sensors create a baseline acoustic “fingerprint” of the line from the internal noise of the pipeline in its undamaged state. When a leak occurs, a resulting low frequency acoustic signal is detected and analyzed. Deviations from the baseline “fingerprint” signal an alarm. It should be noted that there are other methods to detect leaks such as the infrared thermography (IR) and tracer gas. However, these methods are not currently used in North America and therefore, will not be included in this evaluation exercise. Acoustic technology is a NDE method suitable to detect leaks and trapped air in pressurized pipelines. A summary of leak detection technologies is illustrated in Figure 2-5. Since the beginning of the 21st century, a number of new leak detection platforms based on acoustic technology have been developed; these technologies can fall into two distinct categories; external leak and internal leak devices.

Figure 2-5: Acoustic Leak Detection Technology




2.2.3.1 External Leak Devices

External devices fall into two groups: acoustic monitors and correlators. Some acoustic monitor devices must be brought in contact with the pipeline to listen for leakage signals. Other monitors, called geophones, do not come into direct contact with the pipe, valves, or hydrants, but are placed over the location of the pipe. Correlators are based on the velocity of sound made by a leak as it travels through the pipe wall between two geophones or similar sensors. The sensors are situated at convenient locations on the pipe some distance away from, and on either side of, the leak point. The difference in time taken for the sound to travel to each sensor allows the difference in path length to be calculated, from which the leak position can be identified.

2.2.3.2 Internal Leak Devices

One of the most recent leak detection technologies developed is the “In-Pipe Technology.” Leaks can be detected by passing a hydrophone through the interior of the pipe to the point where the leak noise signal is detected. Platforms that are deployed internally to detect leaks are free-swimming tools and tethered tools. As noted in Figure 2-5, there are two major platforms currently used to detect leaks and trapped air based on acoustic technology.

◼ Free Swimming Platform − A free-swimming platform is a platform equipped with sensors that detect leaks and trapped air

in an operating pipeline while acoustic data is recorded as the tool traverses along the length of the pipeline. The flow provides the energy for the platform conveyance in the pipeline, meaning the platform is governed by flow condition and velocity; this is the main limitation of this platform.

◼ Tethered Platform − The tethered system is composed of an acoustic sensor, an insertion assembly, and a cable

drum. With a tethered system, leaks are detected in real time and can accurately be measured by holding the tool in place. The maximum inspection survey is limited to the cable drum length. However, this maximum distance may be reduced due to a cumulative total number of bends from the insertion site and the flow velocity. Most technology vendors have added a visual capability to this platform. However, the quality of visual inspection depends on the flow condition within the pipe.

2.2.4 Remaining Wall Thickness Measurement

Measuring remaining wall thickness is key in assessing the pipe’s structural integrity. Varied NDE technologies were developed to assess remaining wall thicknesses that are applicable to AC and CI. These technologies are based on external measurement (external tools) and internal measurement (in-line tools) capabilities. Advanced NDE methods are typically targeted at continuous or near-continuous measurements of the pipe condition. There are many technologies developed to measure remaining pipe wall thickness based on external and internal devices. However, these technologies vary in their maximum capabilities to measure pipe wall thickness and their ability to inspect a range of pipe diameter. Furthermore, some of these technologies are limited to local measurement capability in detecting wall loss.




3. Inspection Tools

The following sections aim to describe the array of technologies available to complete CI and AC condition assessment, their advantages and disadvantages, and costs associated with completing inspections.

3.1 Nautilus Free-Swimming Leak Detection Tool Nautilus is a 60 mm diameter sphere which incorporates acoustic transducers, microprocessors, memory and rechargeable batteries. It is a neutrally buoyant listening device that detects leaks in most pipe materials including CI and AC pipelines. Nautilus works by being launched into the water distribution system via an entry port as small as 100 mm in diameter and is propelled through the pipe by water flow. The sounds created by leaks or air pockets have individual characteristics which are collected and saved. Once Nautilus reaches the final destination, it is extracted through a port as small as 100 mm via an extraction net (Figure 3-1). The data are uploaded and analyzed by a software program using mathematical algorithms. All the chronological data are then plotted against time and converted to distance based upon the known velocity of the water flow and the time that has passed since insertion. For long pipeline inspections, synchronizers that emit specific acoustic signals are placed aboveground at known Global Positioning System (GPS) locations along the line to provide accurate reference positions. The main Nautilus limitations are the availability of access points, acoustic barriers, and flow control during the inspection.

Figure 3-1: Nautilus Acoustic Ball

3.2 ePulse® – Acoustic Wave Propagation (AWP) Pipe Wall Assessment & Leak Detection Tool

The ePulse® Acoustic Wave Propagation (AWP) pipe wall condition assessment and leak detection tool is a non-invasive measurement technique. It uses induced acoustic measurements to determine the wall condition for pipes ranging from 1” to 60” (25 mm to 1,525 mm). The tool can detect leaks while measuring wall thickness for cementitious and ferrous metal pipelines. For AC and CI pipes, ePulse® measures the average minimum remaining pipe wall thickness over a length of pipe between two sensors. The accuracy of the average minimum remaining pipe wall thickness measurements is within 10% of the actual pipe wall thickness. By knowing the original pipe specifications, the measured average minimum remaining pipe wall thickness can be compared to the original pipe wall thickness to determine the




average percentage of degradation or pipe wall structural loss in the tested segment of pipe. A segment refers to the interval length of pipe between two acoustic sensor connection points. The ePulse® tool detects leaks while measuring the average minimum remaining pipe wall thickness. This capability decreases the assessment costs as it combines the pipe wall assessment and leak detection in the same inspection tool and in the same inspection run. However, ePulse® is unsuitable to assess large diameter pipelines (>1,525 mm) and it only provides an average pipe wall measurement for a segment that is equal to or greater than 100 m in length. Figure 3-2 illustrates an example of the structural component of a pipe wall thickness that is measured using the ePulse® AWP technology for a ferrous pipe.

Figure 3-2: ePulse® AWP Pipe Wall Assessment The technology works when a section of pipe, of known or measured length, is bracketed by two contact points on the main. An out-of-bracket noise source, located outside of that segment, is induced on the pipe. The induced noise source is used to measure and determine the acoustic wave velocity in the section of the pipe using a correlation system. Figure 3-3 and Figure 3-4 provide a detailed overview of a typical ePulse® measurement setup on a distribution watermain and the ePulse® inspection tool, respectively.

Figure 3-3: ePulse Typical Measurement Setup




Figure 3-4: ePulse Inspection Tool Surface mounted sensors can be magnetically attached to appurtenances such as line valves, hydrants, secondary valves, or to the top of the pipe at a sensor-to-sensor. Echologics’s ePulse® pipe wall measurement technology can assess lengths of pipe up to 200 m in length and requires three access points per segment tested (two for the sensors and one for the induced noise source). In the case where there are no available fittings, an access point may need to be created. A 150 mm diameter vacuum excavation to the crown of a pipe is sufficient to access the pipeline and install an acoustic sensor.

3.3 Sahara Technology Leak Detection and visual Tool The Sahara® leak detection tool, shown in Figure 3-5, deploys a hydrophone tethered to a cable. The hydrophone transmits measured noise to a data logger and is capable of detecting leaks as small as 0.01 l/s at pressure of 25 psi and 0.001 l/s at pressure 90 psi. Sahara® requires a full 50 mm (2”) tap connection to insert the inspection device into the pipeline. Sahara® insertion can be completed while the watermain is in-service. Further, the technology requires a minimum of eight feet clearance above the isolating valve at the insertion feature to enable installing the insertion setup for the inspection tool. However, if the minimum clearance is not available, a side insertion may be applicable, but this is determined on a case by case basis. With a tethered system, leaks are detected in real time and can be accurately measured by holding the tool in place. The technology’s limitations include minimum flow velocity, the cumulative total number of bends that limits the length of the survey, and minimum pressure for reliable detection. The maximum cumulative number of bends that the tool can pass is up to 1,350 in a PCCP pipeline and up to 2,700 in a metallic pipeline. However, this varies depending on the flow velocity condition. The minimum pressure for reliable detection is 13 psi.

Figure 3-5: Sahara System Configuration




The Sahara® sensor is tracked from aboveground during the inspection at set intervals and select points of interest. The sensor is tracked using the Sahara Locator®. The Sahara Locator® is an extremely low frequency (ELF) transmitter that is detected by the miniaturized receiver located on the Sahara® sensor head within the pipeline. The frequency used allows accurate through-pipe communication, even within metallic mains with a ground cover of up to ten meters. The accuracy of ground location is typically +/- 500 mm; however, the location accuracy can be affected by the presence of large amounts of steel in or on the ground (such as railroad tracks, rebar, or unusually thick metallic pipe walls), steep slopes, or heavily wooded areas. A technician follows the sensor head aboveground, locating the sensor when requested by the Sahara® operator, typically at a leak, air pocket, or other locations of interest. In addition, the operator can distinguish pipeline features using the Sahara® platform’s CCTV capability. Clarity of the video can be affected negatively by high turbidity, turbulent flow, surface condition of the pipe wall, and when inspecting pipes that are over than 1,200 mm in diameter.

3.4 SmartBall® Technology Leak Detection Tool Pure Technologies Limited also offers an untethered tool for leak detection. The SmartBall® tool is a free-swimming tool equipped with an array of sensors that detect the size and location of leaks in an operating pipeline (Figure 3-6). The sensors are encapsulated in a metal core and protected by a thick foam shell. As the ball rolls down the pipeline, it records acoustic data. At the same time, the tool is also emitting an acoustic pulse which is detected by receivers attached to pipe appurtenances along the pipeline every 600 m– 900 m (2,000’ – 3,000’).

Figure 3-6: The SmartBall® System The location of leaks is estimated based on determining the arrival time of those pulses and the average tool velocity. The distance between each tracking sensor can vary depending on the number of bends between sensors. Although the tool will record leaks between the two tracking sensors, determining the actual location of the leak is limited by sensor placement and velocity consistency. For insertion of the SmartBall® tool inside the pipeline, Pure Technology uses a plunger claw; the claw is vertically installed on top of an isolating valve enabling the insertion of the tool under live flow conditions. For retrieval, Pure Technologies uses an extraction net that is installed on top of the isolating valve which enables extracting the tool under live flow conditions. The insertion plunger requires a minimum of 1.2 m clearance above the isolating valve while the extraction net requires a minimum of five metre clearance above the isolating valve. It should be noted that the SmartBall® tool can be inserted manually via a minimum of 100 mm access flange; however, this will require a temporary depressurization of the system.




The main limitations include flow velocities and threshold pressure for detection. Since the SmartBall® tool rolls at the bottom of the pipeline, it may need flow manipulation to allow it to navigate upward slopes and/or through siphons. Like Sahara®, it requires a 13 psi minimum pressure head to reliably detect leaks.

3.5 Investigator+TM Leak Detection and visual Tool The Investigator+™ operated by GAME consulting, shown in Figure 3-7, is a condition assessment technology that can operate in pressurized watermains and provide visual and leak detection assessments through a single, advanced tethered sensor. The technology can be launched through fire hydrants, pressure fittings, or removed air release valves (ARV) while the watermain remains in-service. It can be used in watermains that range from 75 mm to 300 mm in size. The Investigator+™ can travel with or against the flow of water from the insertion point and has a small footprint which minimizes the impact of inspection on traffic. The system is operated by manually guiding the sensor head within the watermain. The sealing mechanism has also a built-in disinfection functionality which ensures the protection of potable water supplies.

Figure 3-7: The Investigator+TM

The system jointly displays and collects visual and acoustic information throughout the inspection. The camera head at the end of the tether is equipped with a hydrophone which is constantly relaying acoustic information to the control unit. Internal pipe noise such as water flow or leaks can be identified locally with high accuracy. The equipment is tested at pressures of 230 psi and can be operated in live watermain inspections with pressures of up to 200 psi. Inspection distances are directly affected by the size, material and condition of the watermain. Access point preparations include hydrant disassembly, or provision of a direct tap. Hydrants require an isolation valve to prepare the asset for inspection. However, if isolation is not available, temporary depressurization of the main will be required. One of the biggest limitations for this technology is that leaks in lower pressure zones are not audible and hence may not be identifiable. The total setup and inspection time can take up to six hours for every 1,500 m of pipe, depending on the size and direction of inspection.

3.6 Remote Field-Testing Technology (RFT) – SeeSnake Pipe Wall Assessment

The Remote Field Testing (RFT) tools work by measuring the “time of flight” (phase shift) and the signal strength (amplitude) of a signal emitted by an exciter coil and detected by an array of detectors. The detectors are positioned circumferentially so that they are sensitive to every small segment of the pipe circumference. For each




cycle of the exciter frequency, a clock is started and the arrival time of the signal at the detector is used to re-set the clock. The time interval is a measurement of the time of flight, and indirectly, the wall thickness of the pipe. SeeSnake is an RFT non-contact tool that can withstand some internal tuberculation and scale, and can “see through” all non-ferromagnetic liners. SeeSnake is used for inspection of CI, Ductile Iron (DI), and steel pipelines (with or without liners) and can be in free-swimming or tethered mode. In tethered mode, the tool can handle a maximum of 270° of accumulated bend deflections and can inspect over one mile from a single insertion point. Longer lengths can be inspected if used in free-swimming mode. The tools are designed to find localized areas of wall loss and measure the depth and length of local wall loss indications. These parameters are critical in predicting the burst pressures of pipes and thus, preventing leaks and catastrophic burst failures. The technology works in a single-channel RFT probe, shown in Figure 3-8, where there is one exciter coil and one detector coil. Both coils are wound co-axially with respect to the examined pipe and are separated by a distance greater than two times the pipe diameter, depending on the application. The detector’s electronics include high-gain instrumentation amplifiers and steep noise filters, which are necessary to retrieve the remote field signals. The detector electronics output the remote field signals to an on-board storage device. The data is then recalled for display, analysis, and reporting purposes after the examination process is completed.

Figure 3-8: SeeSnake RFT Tool The RFT technology measures attributes such as:

◼ Wall thickness of ferromagnetic pipes; ◼ Magnetic permeability; ◼ Electrical conductivity; and ◼ Stress.

These factors are measured simultaneously and convey important information. For steel pipes, the electrical conductivity remains fairly constant over the length of a pipe segment, meaning that any RFT signal changes along the length of a pipe are mainly due to wall thickness and/or permeability variations. Magnetic permeability is not usually a factor of interest. However, in steel and DI mains that are subjected to soil load stresses, the permeability variations can be significant. For mains known to be under external stresses (for example due to geological ground movement), the permeability variations measured by an RFT tool can be valuable. During the condition assessment, the inspection tool will record discrete wall thickness measurements every two millimetres in the axial direction and every 25 mm circumferentially. This will generate a very high-resolution profile of the pipe condition. Local pitting is detected at or better than +/- 15% of the nominal thickness with 85% confidence for defects above the threshold of detection. General wall loss accuracy will be within +/- 8% of nominal thickness with 85% confidence. The SeeSnake tool uses a low frequency electromagnetic technique. Therefore, to generate a high-resolution profile of the pipe, the speed of testing may be five metre/minute.




The SeeSnake can be affected by:

◼ Overhead high-tension power lines that run near a pipe; ◼ Impressed current cathodic protection (CP), if still active; and ◼ Steel encasements at road crossings.

A full-bore access to the pipe is required to launch the SeeSnake tool. Internal pipeline cleanliness and abrasiveness is a concern when using the internal wall as a seal with the Pull Pipe Inspection Gauge (PIG), which can only be verified during a CCTV inspection. However, for some pipes, both ends of the line can be excavated and a section of a pipe is removed for full bore access.

3.7 p-CAT™ Technology Pipe Wall Assessment Based on technology originally developed by the University of Adelaide, p-CAT™, operated by Detection Services, is a non-invasive, non-destructive method to perform pipe condition assessment while the system remains in operation. It is often described as a screening tool due to its ability to quickly assess long sections and identify small localised “hot spots”. Even though the technology is suitable for all pressurised pipes and applicable to potable, raw and sanitary pipes, it is limited to metallic, concrete, and AC pipes and the pipe must be full of water during testing. This technology locates anomalies to within a higher resolution (one metre) and it is possible to detect wall thickness loss to 0.2 mm. A controlled pressure wave is injected into the pipeline (Figure 3-9), and monitored by sensors installed on existing pipe fittings (Figure 3-10). The transient wave experiences partial reflection when it encounters any change in the pipeline structure. These changes include known system components and other concerning issues related to pipe deterioration. The pressure signal is analyzed by examining the response of the transient wave to the pipeline system to determine all anomalies. By using a pressure wave, the signal is not subjected to any external “noise”. The results measured are detailed because every small reflection back from the transient wave is directly caused by a change in pipe wall condition. The technology is capable to detect and analyze significant anomalies such as air pockets, blockages, sealing status of valves, and unknown pipeline features in addition to wall measurement. The amount of trapped air in the pipe and other factors all affect how far the transient will propagate along the pipeline; generally, between 500 – 1000 m may be considered ideal.

Figure 3-9: Pressure Wave Station Figure 3-10: Collecting Sensor




4. Technology Evaluation Desktop Analysis

AECOM researched several inspection tools applicable to AC and/or CI to measure the wall thickness, detect leaks, and/or conduct visual inspection. Table 4-1 summarizes the tools analyzed along with the vendor supplying each of the tools and the assessment technology used.

Table 4-1: Summary of Inspection Tools Analyzed

No. Tool Name Vendor Platform Assessment Technology 1 Nautilus Pipeline Inspection and

Condition Analysis(PICA) Free swimming Acoustic

2 ePulse® Echologics External sensor Acoustic 3 Sahara® Pure Tethered Acoustic & Visual 4 SmartBall® Pure Free swimming Acoustic 5 Investigator+™ GAME Tethered Acoustic & Visual 6 p-Cat™ Detection Service External Sensor Electromagnetic Principal 7 SeeSnake PICA Free Swimming/Tethered Electromagnetic Principal

The evaluation criteria will include the following major steps:

1. Establishing a set of evaluation criteria that reflects the Municipality’s overall objectives and the characteristics of the water distribution system;

2. Determining the scheme for scoring technologies against the evaluation criteria; 3. Providing initial weights that reflect the relative importance of the criteria and evaluation categories; 4. Aggregating all criteria scores; and 5. Ranking technologies to select the inspection tool.

4.1 Evaluation Criteria Each condition assessment technology platform will have unique capabilities and advantages when compared to other technologies. Likewise, each technology will also have unique limitations and disadvantages. This requires a set of principles and techniques to evaluate the cost-effectiveness and value for utilizing a specific technology to assess CI and AC pipes within the Municipality’s watermain inventory, along with its contribution to the Municipality’s asset management strategy. In addition, the evaluation of the proposed technology must consider and identify all the factors that will affect the pipeline system as a whole. In presenting the evaluation criteria with the Municipality staff, AECOM developed a ranking tool that is based on a set of criteria. Each criterion distinguishes one technology to the other. The model has been developed considering the following:

1. Inspection Risk [Consequence of Technology Platform Failure (CoTPF)]: Classifying the level of effort required to retrieve an inspection tool in the event the tool becomes stuck inside the pipeline;

2. Direct cost: Establishing unit rate costs to utilize a technology to inspect pipelines. The unit rate cost will be assessed in Canadian dollars per meter;

3. Impact to the operation of the distribution network: Assessing the impact on the pipeline to be inspected in terms of hydrants out of service, flow manipulation, temporary depressurization of pipe




segments (between two in-line valves) for tool insertion or extraction, temporary dewatering of pipe segments for insertion or extraction, and dewatering pipe segments for the entire duration of the inspection;

4. Accuracy of results: Assessing the precision range for each technology to identify anomalies and/or measure defects;

5. Resolution of results: Assessing the ability of each technology to measure defects over a pipe length and/or the technology’s sensitivity to identify anomalies;

6. Applicability on different material types: Assessing the ability of an inspection tool to inspect more than one type of material.

4.2 Criteria Scoring and Evaluation The next step in the evaluation process is to determine how each technology will be scored against the evaluation criteria. AECOM developed different categories for each of the evaluation criteria. Each scoring category is explicitly defined and valued, and each technology can meet only one scoring condition. The maximum points that a technology can score in each criterion is ten points and the minimum is zero points. This scale allows both quantitative and qualitative criteria to be measured and normalized. Examples and clarification for each scoring category are developed to ensure the definition of each score is well understood, defensible, and repeatable, including the principles and axioms for scoring each technology.

4.2.1 Criteria 1: Inspection Risk

The scoring scheme for the inspection risk or Consequence of Technology Platform Failure (CoTPF) is displayed in Table 4-2.

Table 4-2: Scoring Protocol - Consequence of Technology Platform Failure (CoTPF)

Score Description Example/Clarifications 10 points No CoTPF. External inspection tool. 8 points Acceptable CoTPF. Tool that can be retrieved with valve operation and/or flow manipulation. 6 points Minor CoTPF. Tool that can be retrieved via depressurizing the pipeline. 4 points Medium CoTPF. Tool that can be retrieved via dewatering the pipeline. 2 points High CoTPF. Tool that can be retrieved via removing inline feature or pipe cut but no excavation is required. 0 points Extremely high CoTPF. Tool that can be retrieved via excavation and pipe cut.

4.2.2 Direct Cost

Costs for field-based condition assessment methods include direct and indirect costs. Direct costs include three major components:

1. Mobilization costs; 2. Inspection costs; and 3. Reporting costs.

Each pipeline is unique in its specifications, operational conditions, in-line features, accessibility, and length. The complexity of each of these factors contributes to the quantification of direct costs.




4.2.2.1 Analysis and Scoring

Through evaluation and analysis of past project costs, a value of $120/m is identified as the threshold cost for cost effective condition inspection. Technologies that exceed this cost will be considered less cost-effective to pursue. For the purpose of this evaluation, a ‘hurdle rate’ of 50% of the threshold cost is established. As a result, technologies having direct costs greater than 50% of the threshold cost rate ($60/m) will score lower points, while technologies having direct costs less than 50% of the threshold cost rate will score 10 points. Table 4-3 outlines the scoring protocol in the “Direct Cost” criteria.

Table 4-3: Scoring Protocol – Direct Cost

Score Description Example/Clarifications 10 points Multiple of ‘hurdle rate’ is less than 1 Direct Costs up to $60/m 8 points Multiple of ‘hurdle rate’ is between 1.0 and 1.9 Direct Costs between $61/m and $120/m 6 points Multiple of ‘hurdle rate’ is between 2.0 and 2.9 Direct Costs between $121/m and $180/m 4 points Multiple of ‘hurdle rate’ is between 3.0 and 3.9 Direct Costs between $181/m and $240/m 2 points Multiple of ‘hurdle rate’ is between 4.0 and 4.9 Direct Costs between $241/m and $300/m 0 points Multiple of ‘hurdle rate’ is greater than or equal to 5.0 Direct Costs exceeding $301/m

An example of scoring the direct cost criteria of each technology follows:

◼ Technology “A” direct cost is $20/m (including inspection, mobilization and reporting) ◼ Technology “B” direct cost is $100/m (including inspection, mobilization and reporting) ◼ Technology “C” direct cost is $10,000/day (including inspection, mobilization and reporting) ◼ Technology “D” direct cost is $10/m; mobilization $5,000; reporting $4,000

Step I – Convert All Direct Costs to Dollars per Metre

Technologies “A” and “B” are provided in dollars per metre and include all direct cost components. Technology “C” direct costs are in dollars per day. Direct cost will be converted as follows:

◼ If the length of time to conduct the inspection of the 220 m pipe test bed exceeds the working hours of the Municipality’s operation and maintenance (O&M) staff, the cost per metre will need to be evaluated based on the length of inspection time required. For example, an inspection requiring two days will be calculated as:

𝑇𝑤𝑜 − 𝑑𝑎𝑦 𝐼𝑛𝑠𝑝𝑒𝑐𝑡𝑖𝑜𝑛 =

2𝐷𝑎𝑖𝑙𝑦 𝐶𝑜𝑠𝑡

𝑃𝑖𝑝𝑒 𝐿𝑒𝑛𝑔𝑡ℎ [1]

Therefore, $10,000 ×2

220 𝑚 = $90.91/𝑚

◼ If the length of time to conduct the inspection of the 220 m pipe test bed is less than the working

hours, the cost per meter will be calculated based on a single day as follows:

𝑆𝑖𝑛𝑔𝑙𝑒 − 𝑑𝑎𝑦 𝐼𝑛𝑠𝑝𝑒𝑐𝑡𝑖𝑜𝑛 =𝐷𝑎𝑖𝑙𝑦 𝐶𝑜𝑠𝑡

𝑃𝑖𝑝𝑒 𝐿𝑒𝑛𝑔𝑡ℎ [2]

Therefore,

$10,000

220 𝑚= $45.45/𝑚




◼ Technology “D” is provided in dollars per meter. However, not all direct cost components are included. Direct costs will be converted as:

$10

𝑚 +

$5,000 + $4,000

220 𝑚= $50.91

Step II – Calculate the Direct Cost Criteria Score

By applying the scoring protocol:

◼ Technology “A” receives 10 points; ◼ Technology “B” receives 8 points; ◼ Technology “C” receives either 10 points for one day of inspection time, or 8 points for two days of

inspection time; and ◼ Technology “D” receives 10 points.

4.2.3 Impact to the Operation of the Distribution Network

Table 4-4 outlines the scoring protocol for the “Impact to the Operation of the Distribution Network” criteria:

Table 4-4: Scoring Protocol – Impact to the Operation of the Distribution Network

Score Description Example/Clarifications 10 points No impact on network: Any change in the network

condition during insertion, inspection, and extraction.

Device that is magnetically attached to the existing feature such as fire hydrants, air valve riser, blind flange, and rods; or device that requires normal operation practice without any change in pipe conditions, such as hydrophones (that requires contact with water column).

8 points Fire hydrants out of service: Temporarily taking fire hydrants connected to the pipe out of service to be inspected.

Device that is inserted and/or extracted via fire hydrants.

6 points Manipulating flows: Manipulating flow velocity or flow diversion.

Device that requires valve operation or increasing or reducing flow capacity via pumping or generating water demands, or closing laterals during inspection.

4 points Temporary pipe depressurization: Pipe temporarily out of service but not dewatered.

Device that requires temporarily depressurizing the pipe section for insertion or extraction during inspection; pipe remains in service during inspection.

2 points Temporary dewatering: Pipe temporarily out of service for tool insertion or extraction.

Device that requires dewatering of the pipe segment for tool insertion or extraction during inspection; pipe remains in service during inspection.

0 points Permanent dewatering: Pipe out of service during inspection.

Device that requires dewatering the entire pipe to be inspected for the entire duration of the inspection; pipe out of service during inspection.

4.2.4 Accuracy of Results

In the context of this study, technology’s accuracy can fall into two distinct categories:

1. Identifying leak detection: the technology’s precision range to locate anomalies in the meter range; and

2. Measuring wall thickness: the ability of a technology to measure and identify the geometry of a defect.




4.2.4.1 Analysis and Scoring – Accuracy: Leak Detection

To repair a pipe, the minimum excavation width required is about one metre, where the centre of the excavation is located over the estimated location of the pipe leak. Technologies that are more accurate in locating leaks will minimize the need to conduct multiple site excavations to find and repair actual leaks. Leak location is identified within an interval upstream and downstream of the estimated leak location. For this study, leak detection accuracy will be scored as outlined in Table 4-5.

Table 4-5: Scoring Protocol – Accuracy of Results (Leak Detection)

Score Description Example/Clarifications 10 points Extremely high capability to locate leaks Detection capability within up to 0.5 m accuracy. 10 points Very high capability to locate leaks Detection capability within 0.5 m to 1.49 m accuracy. 5 points Moderate capability to locate leaks Detection capability within 1.5 m to 1.9 m accuracy. 5 points Low capability to locate leaks Detection capability within 2.0 m to 2.9 m accuracy. 5 points Very low capability to locate leaks Detection capability within greater than 3.0 m accuracy

An example of scoring leak detection technologies follows:

◼ Technology “A” leak locating accuracy is ± 0.3 m ◼ Technology “B” leak locating accuracy is ± 5 m ◼ Technology “C” leak locating accuracy is ± 1% ◼ Technology “D” leak locating accuracy is ± 2 m ◼ Technology “E” leak locating accuracy is ± 3 m

Step I – Convert all leak locating accuracy units to meters

Technology “C” locating accuracy will be calculated as: 1% 𝑥 𝑇𝑒𝑠𝑡 𝐵𝑒𝑑 𝑃𝑖𝑝𝑒 𝐿𝑒𝑛𝑔𝑡ℎ [3] Therefore, 1% 𝑥 220 𝑚 = ±2.2 𝑚 Step II – Calculate leak detection Accuracy of Results criteria score

Applying the scoring protocol from Table 4-5:

◼ Technology “A” receives 10 points and all other technologies receive 5 points.

4.2.4.2 Analysis and Scoring – Measuring Remaining Wall Thickness

While defining accuracy for detecting leaks is a more simplified process, defining accuracy for measuring remaining wall thickness is more complex due to the variety of factors that can affect accuracy. Some of these factors include:

1. Accuracy of pipe specifications and fluid parameters; 2. Technology platform used to perform the inspection; and 3. Position of sensors during inspection.

Most of these factors are influenced by the platform used to inspect the pipeline. For example, free-swimming tools are less accurate than tools requiring staff to physically enter the pipe, since the latter provides greater control of sensor positioning during inspection which can increase the accuracy of the results.




External tools using acoustic technologies are less accurate when compared to other technologies such as electromagnetic, if applicable. Moreover, the accuracy of these acoustic based methods vary based on the spacing distance between sensors, where reduced spacing distance increases accuracy. Finally, technology abilities vary in terms of their ability to identify the geometry of a defect based on the resolution. For these reasons, AECOM recommends that accuracy for measuring remaining wall thickness reflect the ability of the technology to measure and identify the geometry of a defect. This information can be used to estimate the remaining useful life of a pipeline. Table 4-6 outlines the scoring protocol for the “Accuracy of Results” criteria for measuring remaining wall thickness:

Table 4-6: Scoring Protocol – Accuracy of results (Measuring Remaining Wall Thickness)

Score Description Example/Clarifications 10 points Extremely high accuracy Technologies able to identify individual defects with high resolution (in millimetres)

and high number of collected points. Example: Laser based method

8 points Very high accuracy Technologies able to identify individual defects in terms of depth, length and width. Example: Magnetic Flux Leakage (MFL) based method

6 points High accuracy Technologies able to identify individual defects using grade pattern on a localized pipe segment.

Example: Broadband Electromagnetic (BEM) and Ultrasonic based methods 4 points Moderate accuracy Technologies able to identify individual defects in terms of length of defect and

percentage of wall loss. Example: Electromagnetic (EM) principal-based method (Remote Field Testing,

RFT) 2 points Screening accuracy Technologies unable to identify individual defects.

Example: Acoustic based method 0 points N/A N/A

4.2.5 Resolution of Results

In the context of this study, technology resolution can fall into two distinct categories:

◼ For leak detection: The technology sensitivity to identify the size of anomalies in L/s or L/min at a low-pressure range (15-25 psi); and

◼ For measuring wall thickness: the technology’s ability to measure defects over pipe length.

4.2.5.1 Analysis and Scoring – Identifying Leak Size

The capability of a technology to identify leaks within low pressure (15-25 psi) pipe segment is commonly referred to as the ‘technology sensitivity’. This sensitivity will be measured in L/min. For this study, the resolution for leak detection accuracy will be scored as outlined in Table 4-7.

Table 4-7: Scoring Protocol – Resolution of Results (Identifying Leak Size)

Score Description Example/Clarifications 10 points Extremely high resolution Resolution within 0.0 to 0.9 L/min 8 points Very high resolution Resolution within 1.0 to 4.9 L/min 6 points Moderate resolution Resolution within 5.0 to 9.9 L/min 4 points Low resolution Resolution within 10.0 to 14.9 L/min 0 points Very low resolution Resolution greater than 15.0 L/min




An example of scoring leak detection technologies is follows:

◼ Technology “A” leak sensitivity at 15 psi is 0.5 L/min ◼ Technology “B” leak sensitivity at 15 psi is 12 L/min ◼ Technology “C” leak sensitivity at 20 psi is 17 L/min ◼ Technology “D” leak sensitivity at 15 psi is 0.05 L/s ◼ Technology “E” leak sensitivity at 25 psi is 5 L/min

Step I – Convert all leak sensitivity units to similar units (in this case convert to L/min):

Technologies “A”, “B”, “C”, and “E” each have leak sensitivity stated in L/min. Technology “D” leak sensitivity will be calculated as:

0.05 𝑙

𝑠 𝑥

60 𝑠

𝑚𝑖𝑛 = 3 𝑙/𝑚𝑖𝑛

Step II – Calculate leak detection Resolution of Results criteria score:

Applying the scoring protocol from Table 4-7:

◼ Technology “A” receives 10 points ◼ Technology “B” receives 4 points ◼ Technology “C” receives 0 points ◼ Technology “D” receives 8 points ◼ Technology “E” receives 6 points

4.2.5.2 Analysis and Scoring – Measuring Remaining Wall Thickness

Table 4-8 outlines the scoring protocol for the “Resolution of Results” criteria for measuring remaining wall thickness:

Table 4-8: Scoring Protocol – Resolution of Results (Measuring Remaining Wall Thickness)

Score Description Example/Clarifications 10 points High resolution over pipe

segment. Resolution in millimetres over pipe length that can identify individual defects. Example: A laser-based method

8 points High average resolution over pipe segment.

Resolution in regions; the axial and circumferential length in millimetres over pipe length (mm X mm).

Example: An Electromagnetic (EM) principal-based method 6 points High localized resolution but

predicted assessment for pipe segment.

Device that uses grade pattern to provide detailed information on a localized area only.

Example: An ultrasonic based method 4 points Screening resolution over

pipe segment. Device that provides average wall thickness over length of pipe segment (at

least 150 m). Example: An acoustic based method

2 points Visual assessment only. Device that provides visual assessment only, such as cement liner condition, debris, and blockage inside the pipe.

Example: CCTV based method 0 points N/A N/A




4.2.6 Applicability on Different Material Types

This criterion relies on the applicability of the inspection tool on the type of pipe materials, as some inspection tools fail to inspect AC pipelines. A cost-effective tool is the one that is applicable to different types of materials. Therefore, this criterion is customized based on the project’s requirements in inspecting ferrous and AC material, as per Table 4-9. The scoring scheme is based on binary values (either zero or ten points). An inspection tool that is capable of inspecting AC and CI will have a score of ten as it will satisfy the project’s requirements, while the one that fails in inspecting both materials will have a score of zero (it failed to satisfy the requirements). Depending on the number of material types, this criterion can be updated based on the objectives of the inspection.

Table 4-9: Scoring Protocol – Applicability on Different Material Types

Score Description Example/Clarifications 10 points Tool is applicable to AC and CI Using the same tool to inspect a pipeline made of CI

and another made of AC 0 points Tool is not applicable to both AC and CI The tool does not inspect a pipeline made of AC

4.3 Criteria Relative Importance Weights Based on the information presented earlier, there are several inspection platforms that are commonly used in inspecting watermains. Several criteria distinguish one platform from the other based on criteria preference or relative importance. In general, decision-makers confront conflicts in selecting an optimum, near optimum, or a compromise solution that can aid in selecting the final decision. Based on the availability of different alternatives (inspection tools), a compromise solution needs to be reached according to certain attributes, which were discussed in Section 4.2. This program will consider assessing the alternatives by utilizing a simplified ranking method rather than a fuzzy sophisticated mathematical model. The weights are determined based on past projects to conclude the most cost-effective alternative from the considered ones as shown in Table 4-10;

Table 4-10: Criteria Weights

Criteria (j = 1,..,n) Weight (Wj) CoTPF 25% Direct Cost 20% Impact to the Operation of the Distribution Network 20% Accuracy in Measuring Wall Loss or Identifying Leak Location (Accuracy of results) 12.5% Location of Measured Wall Loss or Identification of Leak Size (Resolution of results) 12.5% Applicability on Different Material Types 10% Total 100%

4.4 Technology Ranking The aggregated score (AS) for each technology (i) is calculated using Equation 4. 𝐴𝑆𝑖 = ∑ 𝑊𝑗𝐶𝑆𝑖𝑗

𝑛

𝑗=1 [4]

where W is the initial weight of criteria j and CS is the criteria score that ranges between zero and ten points. The calculated AS for each technology shall be between zero and ten. After computing the AS for all the technologies, the scores are ranked in a descending order.




The ePulse® technology had the highest score, as per Table 4-11Table 4-11. Therefore, this technology is the selected inspection tool based on the weights and scoring scheme considered in evaluating several applicable watermain inspection alternatives.

Table 4-11: Technology Ranking

Alternative Aggregated Score (AS) Rank Nautilus 5.4 6 ePulse® 9.0 1 Sahara® 6.3 4

SmartBall® 5.7 5 Investigator+™ 7.2 3

SeeSnake 4.2 7 p-Cat™ 7.8 2





5.1 Conclusions The development of any condition assessment program should include a cost-benefit analysis to justify its approach relative to expected outcomes. The program should reflect costs associated with evaluating structural and hydraulic failure modes, depending on the specific condition of each pipe in the watermain inventory. Although the water network includes various pipeline materials, this study aims to provide information and a ranking solution for technologies that can inspect AC and CI pipelines. Since there are several technologies capable of inspecting AC and CI pipelines, the efforts in selecting a suitable technology should incorporate a reproducible and defensible method. AECOM established an evaluation criterion and a ranking methodology to conclude the best alternative. Based on the set of criteria and weights, ePulse® technology provided the best outputs as it ranked the first in the evaluation methodology.

5.2 Recommendations Based on information obtained from Technology Vendors and gained through understanding the Municipality’s distribution network requirements and challenges, the following recommendations are proposed:

1. The Municipality should select the ePulse® inspection tool to assess pipe wall thickness and detect leaks;

2. In addition to utilizing the ePulse® inspection tool, the Municipality should include C-Factor tests, and pressure and transient monitoring sensors. While C-Factor tests provide an input to the pipe hydraulic performance, pressure monitoring provides an input on the pressure fluctuations that aid in calculating and verifying the structural integrity to resist hoop stresses;

3. It is recommended that Echologics conduct a site implementation visit and provide a site report to highlight inspection obstacles and all enabling work required to complete the inspection;

4. Following the site visit report, Echologics should provide a detailed inspection plan to inspect critical pipelines identified in Technical Memorandum #2: Initial Criticality Findings, the field activity should include:

− Leak detection using ePulse® platform; − Average wall thickness measurements using ePulse® platform; − C-Factor tests; and − Installation of a minimum of two transient sensors; one at the treatment plant and/or pump

station and another at the lowest point within the water network.

5. Given the costs associated to conduct the transient monitoring and C-Factor tests, it is recommended to include in the inspection pilot a maximum length of 1,000 m of CI and AC pipelines assuming no enabling work is required. This length is based on available funds within Task 4 ($30,000). If enabling work is identified during the site implementation visit, the cost for this activity should be deducted from the overall cost to inspect critical pipelines via the ePulse® inspection tool. However, it is recommended to select pipe segments that do not require any enabling work to




effectively invest in technology demonstration rather than civil and/or mechanical work during the pilot inspection phase.;

6. It is recommended to include DI segments in the pilot although the RFP requires the inspection of CI and AC. This is suggested to demonstrate the applicability of the tool in inspecting DI pipelines; and

7. It is recommended to schedule all field work and more specifically the C-Factor test based on a weather forecast that is above than 0 Celsius to prevent any freezing water hazards.




6. Bibliography

De Silva, D., Davis, P., Burn, L. S., Ferguson, P., Massie, D., Cull, J., et al., 2002: Condition Assessment of Cast Iron and Asbestos Cement Pipe by In-Line Probes and Selective Sampling. International Society for Trenchless Technology.

Opricovic, S., 1998: Multicriteria Optimization of Civil Engineering Systems. Belgrade: Faculty of Civil Engineering.

Opricovic, S., & Tzeng, G., 2004: Compromise solution by MCDM methods: A comparative analysis of VIKOR and TOPSIS. European Journal of Operational Research, 445-455.

Rajani, B., & Kleiner, Y., 2001: Comprehensive review of structural deterioration of water mains: physically based models. Urban water, 151-164.

Statistics Canada, G. o.. 2017, November 29: Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province]. Retrieved October 2018, from https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539027&Geo2=PR&Code2=35&Data=Count&SearchText=Thames%20Centre&SearchType=Begins&SearchPR=01&B1=All&GeoLevel=PR&GeoCode=3539027&TABID=1




aecom.com



Technical Memorandum #4: Inspection Plan and Findings

Prepared by:


Date: January, 2020

Project #: 60586191


Distribution List



Revision History

Revision # Date Details Name Position 1 January 16, 2019 Initial Draft Khalid Kaddoura Asset Management Consultant 2 February 01, 2019 Technical Review Rabia Mady Technical Lead 3 February 07, 2019 Draft Submission Khalid Kaddoura Asset Management Consultant 4 January 20, 2020 Final Submission Michele Samuels Senior Asset Management Consultant


AECOM The Municipality of Thames Centre Technical Memorandum #4: Inspection Plan and Findings

TM4_2020-01-30_Inspection Plan And Findings_60586191_V4.Docx


















Authors

Report Prepared By:

Khalid Kaddoura, PhD, PMP

Report Verified By:

for

Rabia Mady, P.Eng (no longer employed by AECOM)

Report Approved By:

Michele Samuels, M.Eng. MBA, P.Eng.





1. Introduction ....................................................................................... 1



2. Pilot Inspection and Survey .............................................................. 3

2.1 Overview ................................................................................................................. 3

2.2 ePulse®................................................................................................................... 3

2.3 C-Factor Test .......................................................................................................... 4

2.4 Hydraulic Transient ................................................................................................. 5

3. Field Demonstration .......................................................................... 6

3.1 Site Location ........................................................................................................... 6

3.2 Inspected Pipelines ................................................................................................. 7

4. Inspection and Field Results ............................................................ 8

4.1 Water Leak Detection .............................................................................................. 8

4.2 Watermain Structural Condition Assessment .......................................................... 9

4.2.1 Implementing Echologics Results into Likelihood of Failure (LoF) Model – A Comparison .......................................................................................................... 12

4.3 Watermain C-Factor Test ...................................................................................... 13

4.4 Watermain Pressure Transient .............................................................................. 15


5.1 Summary and Conclusions ................................................................................... 18


6. Bibliography .................................................................................... 21




List of Figures Figure 2-1: Typical ePulse® Setup ..................................................................................................................... 4 Figure 3-1: Dorchester Watermains .................................................................................................................... 6 Figure 4-1: POI Potential Location ...................................................................................................................... 8 Figure 4-2: Location of CI Inspected Pipeline .................................................................................................... 10 Figure 4-3: Location of AC Inspected Pipelines ................................................................................................. 10 Figure 4-4: Location of AC and DI Inspected Pipelines...................................................................................... 11 Figure 4-5: Structural Condition Rating of the Inspected Watermains ............................................................... 11 Figure 4-6: Location #1 of C-Factor Test........................................................................................................... 14 Figure 4-7: Location #2 of C-Factor Test........................................................................................................... 14 Figure 4-8: Location #3 of C-Factor Test........................................................................................................... 15 Figure 4-9: Recorded Pressure ......................................................................................................................... 17

List of Tables Table 3-1: Inspected Pipelines Information ........................................................................................................ 7 Table 4-1: Echologics Wall Loss Thickness Loss Evaluation .............................................................................. 9 Table 4-2: ePulse® Watermain Structural Condition Results .............................................................................. 9 Table 4-3: Echologics Results Vs. LoF Model .................................................................................................. 12 Table 4-4: Actual vs. Predicted ........................................................................................................................ 13 Table 4-5: Statistical Summary of Classification ............................................................................................... 13 Table 4-6: C-Factor Test Results ..................................................................................................................... 15 Table 4-7: Pressure Monitoring Results ........................................................................................................... 16

Appendices Appendix A. Echologics: Field Testing Implementation Plan Appendix B. Echologics: Watermain Structural & Hydraulic Condition Assessment – Pilot Trials Appendix C. Likelihood of Failure Map (Dorchester) – Echologics Results



TM4_2020-01-30_Inspection Plan And Findings_60586191_V4.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 59.6 km of watermain infrastructure (1.8 km of watermains are privately owned) to supply water and provide management services to a population of 13,191 residents (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2 (Statistics Canada, Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province], 2017). Unlike wastewater and/or stormwater collection systems, pressurized watermains are often operationally and cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing them in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF), and can present significant risks on the event of an unexpected failure. Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess pressurized watermains. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition, assess failure risk, and estimate residual design life in watermains’ infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing the inspections to minimize the risk exposure while optimizing budgetary allowances. On this basis, the pressurized watermains can be managed preventatively, through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of the assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based state of good repair program to: 1. Prioritize and assess watermains

2. Analyze pipe life cycle

3. Provide an annual funding forecast

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with the procedures and tools to prioritize watermains for inspections including the means to assess existing pipe material inventory and prioritize these inspected watermains for renewal in the short-, mid-, and long-term.




The primary objective of this study is to develop a renewal schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-objectives including, but not limited to, the following:

1. Reviewing inventory data; 2. Identifying failure modes and distress indicators; 3. Developing CoF model including prioritizing pipes for assessment; 4. Matching suitable technologies, and planning a pipeline condition assessment trial for a critical

watermain previously identified by the risk model; 5. Interpreting inspection findings to estimate the likelihood of failure (LoF); 6. Defining the level of service; and 7. Building a comprehensive risk-based decision matrix tree for pipe renewal.

1.2 Objectives for Technical Memorandum #4 The main objectives for this report are to:

1. Discuss the condition assessment plan; 2. Demonstrate the inspections conducted; and 3. Present and review inspection results.




2. Pilot Inspection and Survey

2.1 Overview Performing advanced pipeline condition assessment through the application of in situ, state-of-the-art technologies is a significant step towards efficient preservation of watermain assets. These kinds of inspections/surveys provide essential outputs that demonstrate the existing condition of pipelines, which will aid decision-makers in the allocation of budgets for future intervention actions. In this program, several non-destructive testing inspection technologies (acoustic, visual, and electromagnetic) were considered as an alternative to conducting a pilot inspection. These tools are available in the market in different platforms such as free-swimming, external sensor, and tethered. As each has its advantages and drawbacks, a set of criteria that differentiated between the selected alternatives was developed to select the best alternative. As demonstrated in TM#3: Condition Assessment Plan and Recommended Assessment Methods, the scoring index that was developed was based on six evaluation criteria as follows:

1. Consequence of Technology Platform Failure (CoTPF) 2. Direct Cost 3. Impact on the operation of the distribution network 4. Accuracy of results 5. Resolution of results 6. Applicability on different material types

Of the alternative inspection tools, the ePulse® tool by Echologics scored the highest and was suggested as the tool to conduct the pilot inspection.

2.2 ePulse® The ePulse® Acoustic Wave Propagation (AWP) tool is a non-invasive measurement technique that uses induced acoustic measurements to determine pipe minimum average stiffness for pipes with diameters that range between 25 mm and 1,525 mm. The trial conducted by Echologics followed a segmented approach. The inspections were conducted in segments, in which three hydrants were used. The first and second hydrants were used for equipment installation (which is the segment to be inspected) and the third hydrant was used for tapping to introduce varying frequencies with a hammer made of different materials. A PC Based Correlator attached to a receiver collected the data from the sensors and analyzed the acoustic anomalies. A typical ePulse® setup can be seen in Figure 2-1. The results collected from the ePulse® inspection provided information about leaks and the structural condition of the watermain. More details can be found in Appendix A.




Figure 2-1: Typical ePulse® Setup

2.3 C-Factor Test The C-factor is used in the Hazen-Williams formula [1] as a pipe carrying capacity factor in the calculation of head losses. Lower values of C-factor reflect rougher pipes while higher values indicate smoother pipelines. However, it should be noted that for Asbestos Cement (AC) pipes, higher C values indicate an internal degradation of the AC pipeline due to the decrease of its wall thickness that leads to an increased internal diameter. Since tuberculation and/or build-ups propagation in metallic pipelines, due to internal corrosion, are not the case in AC pipelines, it is expected that the increase of C-factor values is an indicator of AC pipeline’s inner surface deterioration. ℎ𝐿 =

4.73 𝐿 𝑄1.85

𝐶1.85𝐷4.87 [1] Where, ℎ𝐿 Head loss (ft) 𝐿 Length of pipe (ft) 𝑄 Flow rate (cfs) 𝐶 Hazen-Williams C-Factor 𝐷 Internal diameter of pipe (ft) Internal measurements of the roughness of water pipelines are significant. C-factor values are highly relevant to pipe materials. For example, steel and Polyvinyl Chloride (PVC) pipes are smoother and therefore will have less friction loss than Cast Iron (CI) pipes (AWWA, 2005) . However, the C-factor of the same pipe could change during its life-cycle. Watermains are subjected to deterioration which is largely dependent on several factors including ageing of infrastructure. As pipes degrade, the internal surface could differ resulting in different pipe roughness. Changes of internal roughness will obviously impact initial design criteria.




One method for measuring the C-factor values of existing watermains is by actually measuring the pipe roughness in the field by performing head loss tests (Walski, 1984). The test performed at the Municipality of Thames Centre applied the following methodology:

1. Measure the distance between pressure monitoring points;

2. Isolate the test section by closing the required valves;

3. Install pressure recorders at the required pressure monitoring points before testing to obtain static pressure readings;

4. Install Pollard flow testing assemblies on an appropriate flow hydrant;

5. Install pressure recorders on Pollard pitot assemblies to record pitot pressures;

6. Close both control gate valves of the flowmeters connected to the 2 1/2 in ports and open hydrant fully. Slowly open one control gate valve;

7. Let valve flow full open for five minutes and then open second control gate valve and let it flow full open for five minutes; and,

8. Slowly close one control valve and then the other.

2.4 Hydraulic Transient Walski et al. (2007) defined hydraulic transient as “the flow and pressure condition that occurs in a hydraulic system between and initial steady-state condition and a final steady-state condition.” The same authors also defined the steady-state condition when the hydraulic demand does not change with the boundary conditions with respect to time. Steady-flow, however, is characterized by a constant velocity over time (Munson et al. 2009). Any deviation that occurs in the system that results in a change of a steady-state to another will cause hydraulic transient. During this condition, the flow that is running along the cross-section of the pipeline is denoted as the unsteady flow. Hydraulic transient are commonly found in areas of pump stations, valves, elevated areas, etc. (Friedman, 2003). During hydraulic transient, the flow is responsible in forming pressure waves which could have some impacts on plant, equipment, personnel in the plant, and society (Wood, 2005). Transient conditions will initiate high or low pressures within the system. In transient analysis, for every 1 ft/s sudden drop in velocity, the water increases 50 to 60 psi (depending on the pipe attributes and dimensions, etc.) (Hoagland, 2016). Any increase in flow velocity will result in a decrease in pressure (Kirmeyer et al. 2001). If a pressure rating is exceeded due to high transient pressure, a watermain will break. Any negative pressure, however, will cause the pipeline to collapse inward or absorb contaminants from the existing groundwater (Walski et al. 2007). In either case, excessive transient pressure will hinder the condition of the system and may result in failure. A watermain transient pressure monitoring was conducted at the Municipality of Thames Centre. Echologics installed two transient pressure recorders within the Dorchester area. The first recorder was located at the water pump station which is within the water treatment plant (WTP) directly downstream of the discharge pumps. It was installed at the WTP location due to pump cycling required. Although it is recommended to use the second recorder at the lowest elevations of the network, it was installed at the lower base of the water tower location due to site limitations.




3. Field Demonstration

3.1 Site Location Technical Memorandum #2: Initial Criticality Findings demonstrated the methodology performed in calculating Consequence of Failure (CoF), Likelihood of Failure (LoF), and risk scores. TM #2 also provided a framework to develop a list of prioritized AC and CI pipelines for inspection. After selecting ePulse®, in Technical Memorandum #3: Condition Assessment Plan and Recommended Assessment Methods, as the suitable inspection tool, AECOM provided Echologics a list of pipelines that were sorted based on their risk scores. The vendor checked the job site and the applicability of the tool before informing AECOM appropriate pipelines for inspection given budget constraints ($30,000). The inspection was carried out on a total of up to one kilometre of some of the critical pipelines previously identified in TM #2 in the Dorchester area. Figure 3-1 illustrates the watermain system.

Figure 3-1: Dorchester Watermains




3.2 Inspected Pipelines Approximately, one kilometre of watermains, located in Dorchester, were selected for inspection to understand their structural condition. The inspection was carried out on six individual segments as listed in Table 3-1. Three of these segments are made of Asbestos Cement (AC), two are made of Ductile Iron (DI), and only one segment is made of Cast Iron (CI). The total length of the AC, DI, and CI inspected pipelines were 411 m, 438 m, and 131 m, respectively. The diameter of each segment is 150 mm and the installation year ranged between 1956 and 1974. The pressure class for CI and AC pipelines is 150, while the pressure class for the DI pipelines is 52. Echologics extracted the properties of the pipelines from the as-built drawings that were provided by the pipe owner and/or were assumed based on their project experience. It should be noted that any assumption that was taken into consideration was pre-approved by the Municipality of Thames Centre.

Table 3-1: Inspected Pipelines Information

Pipe Material Length (m) Installation

Year Pressure

Class Internal

Diameter (mm) Nominal

Thickness (mm) Lining Thickness

(in) CI 131 1956 PC150 150 9.7 NA AC 114.5 1969 PC150 150 16.8 NA AC 218 1969 PC150 150 16.8 NA AC 78 1974 PC150 150 16.8 NA DI 219 1974 Class 52 150 7.9 1.6 DI 218.5 1974 Class 52 150 7.9 1.6




4. Inspection and Field Results

This section will provide an overall summary and discussion about the inspection and field results. For more information regarding the inspection results, refer to Appendix B.

4.1 Water Leak Detection As discussed in TM #3, ePulse® detects leaks while measuring wall thickness. This added value was utilized at the Municipality of Thames Centre’s inspection pilot. While performing the inspection using the ePulse® tool on six pipelines, Echologics observed only one point of interest (POI) along Minnie Street. The vendor claimed that the field practitioner was relatively confident that the source of noise indicated a leak. The noise source was detected at or close to the T-joint near the intersection of Minnie Street and North Street as indicated in Figure 4-1. Although the location of the POI was outside of the scope of work area, the vendor dedicated some efforts to check the source of noise by attaching sensors to a service valve on Minnie St. east to North St.; however, the test was inconclusive. In order to confirm whether the POI represents a leak, the vendor has to obtain three positive correlations while using the sensors on all the sides of the T-joint. Therefore, the source noise could not exactly be located, whether it is at the T-joint or along Minnie St. (east of the T-joint). Additional investigation is required, which may require a pothole, to pinpoint the noise source and verify if the POI represents a leak or not.

Figure 4-1: POI Potential Location

Likely Leak area from POI




4.2 Watermain Structural Condition Assessment The ePulse® inspection tool measures the average minimum thickness of the pipeline along the pipe segment inspected. The evaluation criteria displayed in Table 4-1 compares design thickness with measured mean thickness. The results are categorized into three groups: Good, Moderate, and Poor. The Good category reflects thickness loss that is less than 10%, while the Moderate category describes pipelines that lost 10% to 30% of their designed thickness. The Poor category, however, denotes to pipelines having remaining wall thickness that is less than 70%. It should be noted that this pipe condition classification is based on the vendor’s condition matrix. The supplied information is critical to the pipeline specifications and dimensions including the pipeline material, internal diameter, and modulus of elasticity.

Table 4-1: Echologics Wall Loss Thickness Loss Evaluation

% Change in Hoop Thickness

Description Metallic Pipes Description

<10% Good Minor levels of uniform corrosion or some localized areas with pitting corrosion.

Defer/Low Priority

10% to <= 30% Moderate Considerable levels of uniform surface or internal corrosion and/or localized areas of pitting corrosion.

Monitor/Medium Priority

>30% Poor Significant uniform corrosion and/or numerous areas of localized pitting corrosion.

Address/High Priority

The total length of the inspected pipelines was approximately 980 m. Based on the results, the CI inspected pipeline was rated as Moderate since its percentage change of wall thickness was 25%. Similarly, two of the AC inspected pipelines were rated as Moderate as their percentage change of wall thickness were 13% and 27%. However, the third AC inspected pipeline was categorized as Poor since its percentage change of wall thickness was 32% (>30%) although it was installed five years later compared to the other two AC pipelines. One of the two DI pipelines surveyed was rated as Good while the other was rated as Poor (Table 4-2).

Table 4-2: ePulse® Watermain Structural Condition Results

Pipe Material Length (m) Street Remaining

Thickness (mm) % Change from

Equivalent Nominal Echologics Rating

CI (Figure 4-2) 131.0 Minnie Street 7.3 25% Moderate AC (Figure 4-3) 114.5 Thames Crescent 12.2 27% Moderate AC (Figure 4-3) 218.0 Thames Crescent 14.6 13% Moderate AC (Figure 4-4) 78.0 Canterbury Drive 11.5 32% Poor DI (Figure 4-4) 219.0 Sherwood Crescent 7.8 9% Good DI (Figure 4-4) 218.5 Huntington Drive 5.7 34% Poor




Figure 4-2: Location of CI Inspected Pipeline

Figure 4-3: Location of AC Inspected Pipelines




Figure 4-4: Location of AC and DI Inspected Pipelines As per Figure 4-5, 23% of the total inspected length, in this pilot, was rated as Good; 47% was rated as Moderate; and 30% was rated as Poor.

Figure 4-5: Structural Condition Rating of the Inspected Watermains

AC




4.2.1 Implementing Echologics Results into Likelihood of Failure (LoF) Model – A Comparison

The inspection included segments that were sorted and ranked based on their risk scores as demonstrated in TM #2 as well as the recommendation to select additional material types including AC and CI. As ePulse® is applicable to ferrous material, some recommended DI pipelines were included in the inspection. Based on the suggested list of pipelines, the vendor performed a site visit to check the applicability of the tool to minimize any required enabling work and to check site conditions to ensure minimum and maximum inspection length was attained. The entire original Object IDs of the segments, that the vendor used to select the appropriate sample, are revisited and the Likelihood of Failure (LoF) ranks are checked. According to the model, the entire LoF ranks of the sample were categorized as Medium. To establish a comparison framework, a baseline must be considered. In this case, the segments evaluated by ePulse® were compared with the outputs of the Medium ranks that was supplied by the LoF model. To be consistent with the rankings of Echologics, Good = Low; Moderate = Medium; and Poor = High (Table 4-3). It is important to note that an inspected segment could be represented in multiple objects based on the Object ID. For example, Echologics inspection ID 82241A005 would approximately represent two objects based on the GIS, DC_WM_1171 and DC_WM_1193. In this case, the same inspection result is considered for both GIS segments. Due to this consideration, it would be assumed that the average remaining wall thickness is similar for both. In general, average remaining wall thickness measurements are used to perform further analysis to calculate the remaining factor of safety while considering the existing external and internal pressures. Upon calculating the remaining factor of safety values, the likelihood of failure would be estimated and classified. However, to update the likelihood of failure classifications, the categories supplied by Echologics were assumed and mapped as shown in Appendix C. The appendix displays the three individual classifications of the likelihood of failure in the Dorchester area, in which the inspected pipelines’ classifications were updated and the remaining pipelines’ likelihood of failure categories remained unchanged (refer to Technical Memorandum # 2).

Table 4-3: Echologics Results Vs. LoF Model

ID Echologics ID Material % Change from Equivalent Nominal Echologics LoF Description

DC_WM_1343 82241A001 CI 25% Moderate Moderate DC_WM_1088 82241A003 AC 13% Moderate Moderate DC_WM_1085 82241A002 AC 27% Moderate Moderate DC_WM_1219 82241A002 AC 27% Moderate Moderate DC_WM_1203 82241A006 DI 34% Poor Moderate DC_WM_1171 82241A005 DI 9% Good Moderate DC_WM_1193 82241A005 DI 9% Good Moderate DC_WM_1163 82241A004 AC 32% Poor Moderate DC_WM_1167 82241A004 AC 32% Poor Moderate

A confusion table was formed for each category to compute the accuracy of the classification, as shown in Equation [2] (Kaddoura & Zayed, 2018). This comparison is established to check the performance of the classification of the qualitative conclusions attained. In this comparison, the actual data are the outputs from Echologics, and the predicted ones are from the LoF model. The higher the accuracy percentage, the better is the prediction model in terms of classification. However, the results are highly dependent on the data points and the number of data points in each classification.




Table 4-4 shows the comparison between the qualitative outputs for each. The two indicators are calculated after finding the True Positive (TP), True Negative (TN), False Positive (FP), and False Negative (FN). The confusion matrix for each category is formed to verify whether a classification under a certain category is attained or not. 𝐴𝑐𝑐𝑢𝑟𝑎𝑐𝑦 =

𝑇𝑃 + 𝑇𝑁

𝑇𝑃 + 𝑇𝑁 + 𝐹𝑃 + 𝐹𝑁 [2]

Table 4-4: Actual vs. Predicted

Data Rank Actual

Good Moderate Poor LoF Model Prediction Good 0 0 0

Moderate 2 4 3 Poor 0 0 0

To find the confusion matrix of the Good category, the following was considered:

◼ TP: actual is Good and predicted is Good. In this case, the value is zero. ◼ FP: actual is Moderate or Poor and predicted is Good. In this case, the value is zero. ◼ FN: actual is Good and predicted is Moderate or Poor. In this case, the value is two. ◼ TN: actual is Moderate or Poor and predicted is the same. In this case, the value is seven.

Table 4-5 summarizes the accuracy result of each category after using Equation [2]. The accuracy percentage of Poor classification is 67%. This percentage is attained as the prediction model ranked three pipelines as Moderate where the actual ranks were Poor (three pipelines) and Good (two pipelines). Nevertheless, the actual data points for these five pipelines are closer to the Moderate categories. The vendor stated that the results were highly sensitive to the measured length. For the case of the DI pipeline located along the Huntington Drive, a three-metre error in the pipe length measurement would cause a 7% error in the remaining wall thickness measurement. In case of an error that results in greater remaining wall thickness than the calculated, the percentage change from the nominal is calculated as 29% instead of 34%. This calculated percentage is translated as Moderate based on Echologics’ condition rating. It is true that the accuracy is not considered high, the classifications that resulted in these low values are close to the Moderate category. Any error or variance that changes the actual measurements to Moderate will drastically change the accuracy values to 100%.

Table 4-5: Statistical Summary of Classification

Rank Accuracy Good 78%

Moderate 44% Poor 67%

4.3 Watermain C-Factor Test Three different C-Factor tests were conducted to measure internal roughness of the watermains and have general view of the internal condition of the pipeline. The following three locations are illustrated in the following figures.




Figure 4-6: Location #1 of C-Factor Test

Figure 4-7: Location #2 of C-Factor Test




Figure 4-8: Location #3 of C-Factor Test The C-Factor tests were performed on AC and DI pipelines. The recommended designed Hazen-Williams C-Factor value for AC and DI is 140. Based on Table 4-6, the measured C value for DI was lower than the designed C-Factor, which indicates that tuberculation might be present and/or the cement mortar lining might be degrading, which may lead to internal corrosion, given contaminated water flow. For AC pipeline, however, one value showed some increase in the C-Factor, which indicates the decrease of the wall thickness due to internal degradation. It should be noted that previous tests on AC pipes showed a variety of C-Factor values for different pipe diameters, and the recommended C-Factor value was between 140 and 160. However, the design approach took a conservative value of 140 to address the variance values in C-Factor for different pipe diameters.

Table 4-6: C-Factor Test Results

Location Street Distance (m) (P1 to P2) Material Internal

Diameter (mm) C-Factor

1 Thames Crescent - East Flow 265 AC 150 142 2 Thames Crescent - West Flow 220 AC 150 140 3 Minnie Street - West of Clara Street 128 DI 250 128

4.4 Watermain Pressure Transient The inspection recorded the average, minimum and maximum pressures between the two locations between November 27th, 2018 and December 6th, 2018. An overview of the results is displayed in Table 4-7. However, the comprehensive record of the test is illustrated in Figure 4-9.




Table 4-7: Pressure Monitoring Results

Location Average (m) Minimum (m) Maximum (m) WTP 22.2 21.5 22.9

Water Tower 45.4 39.3 56.3 Records demonstrated that there were two to three pump cycles in a day. Yet, these cycles did not trigger a transient channel, based on the location of the two installed devices. It may also be concluded that the variations in the states captured were not identified as transient. The same figure also displays that there was some pressure increase from 40 m to 55 m whenever a pump cycle is triggered on. Nevertheless, the pump operation did not form any transient pressure. To obtain some robust conclusions about transient pressure, however, it is recommended to install additional sensors in multiple locations, especially at lower elevations of the water network. Doing so will capture any dissipated transient pressure, if available.




Figure 4-9: Recorded Pressure





5.1 Summary and Conclusions This report provided the findings of pilot inspections and surveys to have an overview of selected critical watermain located in the Dorchester area in the Municipality of Thames Centre. The inspection was performed on six individual pipe segments that included DI, CI, and AC materials. This assessment was performed to measure the average remaining wall thickness. The second test that was performed measured the C-factor value of three segments; two were made of AC and one was made of DI. Pressure transient monitoring equipment was also attached to record and monitor the pressure fluctuation in two different locations. Based on the pilot tests and surveys on the inspected pipelines, the following was concluded:

1. The ePulse® tool detected one POI during the inspection. The most likely observation was a leak that was located at a joint or service connection.

2. With regard to the structural condition evaluation based on the average minimum thickness,

a. One DI pipeline segment was rated as Good. The average thickness change was measured as 9%.

b. Three pipeline segments were rated as Moderate since the average thickness change was between 10% and 30%. Two of these pipelines were made of AC and the third one was made of CI.

c. Two pipeline segments were rated as Poor as the average change of the thickness was more than 30%. One pipeline was made of AC and the other was made of DI.

3. The LoF model that was developed in TM #2 was compared with the classifications supplied by Echologics. The accuracy indicator was adopted to check the performance of the classification. The average accuracy was 63%. Nevertheless, the classification differences between the actual and the predicted ones were minimal as they were close the Moderate boundary.

4. The two C-factor tests for AC pipelines provided values that were equal or close to recommended designed C-factor. The measured C-factor values for the two AC segments were 140 and 142. Based on these results, the tested segments did not show significant change in C-Factor values that can indicate internal degradation of the AC pipelines. However, the measured value for the DI segment was 128, which showed a reduction of the designed C-factor (140). This indicates that tuberculation may be present and/or internal cement liner is detreating, which may lead to internal corrosion due to internal surface exposure to water contaminants.

5. The average system pressure at the water treatment plant pump was approximately 45 m and it varied between 40 m when pumps were off and 55 m when they were operating. There were two to three pump cycles recorded in a day, which is not believed to be excessive for the existing system. The pressure monitoring process did not indicate any pressure transient, based on the recordings of the installed devices.




5.2 Recommendations 4. As stated by Municipality staff, watermains backfill material is suspected to be the root of several problems to

many of the watermains. Depending on the leak flow and other parameters including the surrounding environment, the land surface (where leak exists) collapses due to formed cavities. Therefore, AECOM suggests performing additional field investigations on the suspected leak to locate the detected POI and verify if the noise was actually a leak. This could include surveying service connections along Minnie Street east of the intersection of Minnie Street and North Street after performing some enabling work (potholes) to avoid any sound propagation problems.

5. Similar to this pilot, AECOM suggests performing an assessment study to evaluate conditions of the remaining critical watermains previously identified by the risk model. Performing the inspection will aid in comparing the results of the LoF with the actual results. The statistical comparison’s reliability will increase with an increase of the sample data. The actual inspection results shall be further incorporated in the LoF model to update the risk scores. For example, if the LoF for a certain segment calculated using the two-parameter Weibull was low and the actual inspection finding was Poor, the LoF in the risk model must be updated to high. Based on the staged condition assessment or intervention plan decision matrix, the Municipality can base their decisions accordingly.

6. Although the total length of CI materials is not drastic compared to the others, AECOM suggests performing a C-factor test on CI segments to verify existing internal roughness. In general, it is recommended that the C-factor test be conducted for all Moderate and Good condition pipes segments to assess their hydraulic performance. The findings from this investigation should be incorporated in a hydraulic model to provide a hydraulic analysis and/or input to a calibrated hydraulic model.

7. Although ePulse® provides information about the average remaining wall thickness, it does not differentiate between an external or internal degradation. Therefore, AECOM recommends performing a root case analysis to identify the source of the environmental impact leading to corrosion. This can be done by conducting a geotechnical investigation to check the corrosivity of soil as it may be a leading factor for wall thickness degradation from the exterior surface of the pipe. AECOM also recommends performing water quality testing, as aggressive water will indicate if the pipe is internally degrading.

8. Based on Echologics’ classification matrix for AC pipelines, it is recommended to perform an intervention renewal plan to avoid sudden AC failures that could disrupt the system.

9. As excessive transient pressure could be an indicator for pipeline failure and given the existing water network formation, it is recommended to conduct another transient pressure monitoring test by installing devices in multiple locations especially at lower elevations of the network. This test can be performed in a suitable weather, where sensors can be installed aboveground feature without being damaged. Additional conclusions about transient pressure can be made as utilizing multiple monitoring sensors may capture any dissipated transient pressure, if available.

10. It is recommended to perform an applied load analysis to measure the remaining factor of safety. This could be done by considering the external and internal pressures imposed on the pipelines as well as the measured average wall thickness. Based on the calculated remaining factor of safety, an estimated likelihood of failure is concluded.

11. It is recommended that a root cause analysis be conducted for every structural failure by performing destructive tests on fractured pipe segments. The findings and results from these investigations are valuable, in that they can be used as data input in any advanced condition assessment process for the water pipeline




system. They can also be used to confirm or validate pipe specifications. Below is a list of the recommended analysis and tests that should be part of an investigation of each structural failure:

a. Documenting (including pictures) and visually inspecting the corroded failed areas, wall thickness measurements, location of the fracture, failure date, and shape;

b. Recording the operational condition at the time or near the time of failure and any change of the normal operating conditions before the failure occurs;

c. Conducting chemical analysis to identify mixed metallurgy systems;

d. Performing soil chemistry analysis;

e. Conducting hardness and tensile tests of the broken segment;

f. Analyzing coating and lining material;

g. Measuring and analyzing corrosion; and

h. Developing metallography analysis.




6. Bibliography

AWWA, 2005: Computer Modelling of Water Distribution Systems. Manual of Water Supply Practices-M32. Denver: AWWA.

Friedman, M. C., 2003: Verification and control of low pressure transients in distribution systems. 18th Annual ASDWA Conf., Association of State Drinking Water Administrators. Boston.

Hoagland, S., 2016: TRANSIENT-BASED RISK ANALYSIS OF WATER DISTRIBUTION SYSTEMS. University of Kentucky.

Kaddoura, K., & Zayed, T., 2018: Erosion Void Condition Prediction Models for Buried Linear Assets. Journal of Pipeline Systems Engineering and Practice.

Kirmeyer, G., Friedman, M., Martel, K., Howie, D., LeChevallier, M., M., A., et al., 2001: Pathogen Intrusion Into the distribution system. AWWARF. Denver.

Munson, B., Young, D., Okiishi, T., & Huebsch, W. (2009). Fundamentals of Fluid Mechanics. New Jersey: John Wiley and Sons, Inc.

Statistics Canada, G. o., 2017, November 29: Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province]. Retrieved October 2018, from https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539027&Geo2=PR&Code2=35&Data=Count&SearchText=Thames%20Centre&SearchType=Begins&SearchPR=01&B1=All&GeoLevel=PR&GeoCode=3539027&TABID=1

Walski, T. M., 1984: Analysis of Water Distribution Systems. New York.

Walski, T. M., Chase, D. V., Savic, D. A., Grayman, W., Beckwith, S., & Koelle, E., 2007: Advanced Water Distribution Modelling and Management. Bentley Institute Press.

Wood, D. J., 2005: Waterhammer Analysis – Essential and Easy (and Efficient). Journal of Environmental Engineering.


Appendix A

Echologics: Field Testing

Implementation Plan


Thames Centre Condition Assessment Project Echologics Project No. 42218224

Field Testing Implementation Plan

November 23, 2018


Table of Contents

Project Scope ................................................................................................................................................ 1

Technology Overview and Detailed Implementation Plan - ePulse .............................................................. 3

Implementation Procedure – ePulse Condition Assessment: ......................................................... 4

Detailed Implementation Plan - C-Factor Testing ....................................................................................... 12

Detailed Implementation Plan - Pressure Transient Monitoring ................................................................ 14

Confirmed Field Testing Schedule .............................................................................................................. 15

Municipal Staff Support & Information Requests ....................................................................................... 16


1

Project Scope

AECOM has contracted Echologics to gain information on segments of cast iron, ductile iron and asbestos cement water mains within the water distribution system of the Municipality of Thames Centre in order to address two primary objectives:

Determine the condition of the water mains Investigate the main for the existence of any potential leaks

In order to meet these objectives, Echologics will provide condition assessment services through our proprietary ePulse® technology combined with C-Factor testing & transient pressure monitoring. For this project, Echologics will assess up to one kilometer of pipe using ePulse, complete three C-Factor tests and install up to two transient pressure loggers for 1-week in Thames Centre within the Dorchester water distribution system. Figure 1 shows an overview map of the pipe network in Dorchester, ON.

Figure 1: Dorchester Water System Overview


2

Table 1 below outlines the pipe types that will be tested as part of this survey. Approximate pipe distances were taken from the GIS data provided by AECOM and the distances are based on the estimated segments lengths being tested located between acoustic sensor monitoring points. Actual distances for the tested segments will be confirmed on-site using measuring wheels. For the condition assessment analysis, Echologics will need more information regarding pipe specifications such as pipe class or original wall thickness. This is discussed in more detail in the Information Request section below.

Table 1: Selected Test Pipe Specifications

Material Diameter (DN) Length (m) CI 150 129 DI 150 441 AC 150 415

Total 985


3

Technology Overview and Detailed Implementation Plan - ePulse

For ePulse testing, the Echologics team will use the LeakFinderST correlator. This system consists of two sensors attached magnetically to water valves or the pipe wall. The sensors are connected by cable to a transmitter which communicates with a receiver attached to a technician’s computer. The technician also induces noise into the pipe at a third point by gently flowing a hydrant or lightly tapping on a valve or hydrant. Acoustic data is processed onsite to determine if it is acceptable for condition assessment calculations. The equipment measures the speed of sound within the water main.

After field work is complete, the speed of sound is combined with other information collected onsite, including distance and water temperature measurements, to determine the mean minimum remaining hoop stiffness which is turn converted to mean minimum remaining pipe wall thickness for DI, CI and AC mains.

Figure 2: LeakFinderST Acoustic Correlator. A sensor is connected magnetically to the valve and by cable to the transmitter.

To qualify for condition assessment testing, sections of pipe between available sensor connection points should approximately be 100m to 220m in length with a recommended maximum spacing of 230m and not be composed of changes in materials or diameters. Echologics has identified six (6) segments that qualify for ePulse® testing within the Dorchester water distribution system.


4

Implementation Procedure – ePulse Condition Assessment: 1. A health & safety briefing conducted by Echologics will occur daily prior to commencing field work. 2. The ePulse field measurements will be conducted on segment 8224te001 located on Minnie Street

between Clara Street and North Street. The segment measures approximately 129m of 150mm Cast Iron pipe. For this segment, acoustic sensors will be placed on inline valves DC_WCV_369 and DC_WCV_1543 as shown below in Figure 3. Hydrants DC_WH_157 and DC_WH_124 will be used as noise sources. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe.

Figure 3: Overview Map of Segment 8224te001


5

3. The ePulse field measurements will be conducted on segment 8224te005 located on Thames Crescent between Hamilton Road and Terrence Avenue. The segment measures approximately 117m of 150mm Asbestos Cement pipe. For this segment, acoustic sensors will be placed on inline valve DC_WCV_431 and hydrant valve DC_WCV_434 as shown below in Figure 4. Hydrant DC_WH_144 will be used as a noise source. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe



6

4. The ePulse field measurements will be conducted on segment 8224te003 located on Thames Crescent between Terrence Avenue and Alma Street. The segment measures approximately 221m of 150mm Asbestos Cement pipe. For this segment, acoustic sensors will be placed on hydrant valves DC_WCV_434 and DC_WCV_430 as shown below in Figure 5. Hydrants DC_WH_144 and DC_WH_145 will be used as noise sources. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe.



7

5. The ePulse field measurements will be conducted on segment 8224te006 located on Sherwood Place and Sherwood Crescent west of Sherwood Place. The segment measures approximately 221m of 150mm Ductile Iron pipe. For this segment, acoustic sensors will be placed on hydrant valves DC_WCV_404 and DC_WCV_409 as shown below in Figure 6. Hydrants DC_WH_137 and DC_WH_139 will be used as noise sources. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe.



8

6. The ePulse field measurements will be conducted on segment 8224te007 located on Canterbury Drive between Dorchester Road and Huntington Drive. The segment measures approximately 77m of 150mm Asbestos Cement pipe. For this segment, acoustic sensors will be placed on hydrant valve DC_WCV_418 and inline valve DC_WCV_403 as shown below in Figure 7. Hydrant DC_WH_140 will be used as a noise source. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe.



9

7. The ePulse field measurements will be conducted on segment 8224te009 located on Huntington Drive near Canterbury Drive. The segment measures approximately m of 220mm Ductile Iron pipe. For this segment, acoustic sensors will be placed on hydrant valve DC_WCV_412 and inline valve DC_WCV_421 as shown below in Figure 8. Hydrant DC_WH_33 will be used as a noise source. Noise with the hydrant will be created through flowing using a 2 ½” hydrant cap flow assembly and by gently tapping on the top nut with a rubber mallet. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser and pipe.



10

8. Table 2 shows the segments selected for testing with the two sensor connection points identified (Fitting1 and Fitting2). The segment length is initially estimated using GIS.

Table 2: Sites Selected for Testing

Area Segment # Fitting1 Fitting2 Size (DN) Material

Segment Length

(m)

1 8224te001 DC_WCV_369 DC_WCV_1543 150 CI 129 2 8224te005 DC_WCV_434 DC_WCV_431 150 AC 117 2 8224te003 DC_WCV_430 DC_WCV_434 150 AC 221 3 8224te006 DC_WH_137 DC_WCV_404 150 DI 220 3 8224te007 DC_WCV_403 DC_WCV_418 150 AC 77 3 8224te009 DC_WCV_412 DC_WCV_421 150 DI 221

Total 985 9. For the tested segment, the following procedure will be completed:

a. An accurate measurement of the pipe segment being tested will be taken on site using a calibrated measuring wheel.

b. Acoustic sensors, known as accelerometers, will be place on each hydrant isolation valve to bracket the segment being tested. An example depicting the sensors resting on the hydrant are shown below.

c. An initial correlation measurement is taken using the LeakFinderST system and LeakFinder software to establish whether any existing leaks are present within the segment. If an acoustic noise is correlated and recorded, further investigations are completed to confirm whether the noise is an actual leak or possible consumption and/or external noise source (pump, gas main, control valve, etc.). For this test segment, it is expected that noise sources from consumption and/or external noise sources will not be present.


11

d. Utilizing the “noise source” hydrant and/or valve, a series of tap tests are completed by lightly tapping on the bottom flange of the noise source hydrant while another technician “listens” to the LeakFinderST receiver to ensure the acoustic wave can be heard at each of the sensor locations.

e. A 2 ½” hydrant cap with flow nozzle & ball valve are installed on one of the side ports of the selected flow hydrants outside of the bracket of the segment being tested. Note: Echologics will provide the 2 ½” hydrant cap flow diffuser. The hydrant is opened and operated by Thames Centre operators and a flow of approximately 25 to 60 lpm is established at the flow hydrant.

f. Water temperature readings are taken at the flow hydrant during the test.

g. The LeakFinderST and LeakFinder software are then utilized to confirm acoustic propagation from the flow hydrant across both sensors bracketing the test segment. If may be necessary to adjust the flowrate from the flow hydrant to maximize the acoustic signal for the ePulse measurement.

h. Once the optimum acoustic site conditions have been established, an acoustic wave file is recorded using the LeakFinderST software. An initial field measurement of the acoustic wave velocity is completed on site to ensure results are within expected parameters. The recording of the wave file will very between 5 to 15 minutes. The LeakFinderST and LeakFinder Software are depicted below:

i. Following the wave file recording, the flow hydrant is closed and all field equipment is removed and moved to the next segment setup where the process is repeated.

j. Echologics estimates the survey of each segment will take approximately 1 hour to complete.

10. All field data that was recorded is then analysed further by Echologics technicians and engineers in the office and is subjected to our proprietary algorithms to establish the average minimum remaining pipe wall thickness for each segment tested.

11. An engineering report is then prepared that provides the pipe wall assessment results.


12

Detailed Implementation Plan - C-Factor Testing Echologics has identified three potential C-factor testing locations which can be seen in Figures 9, 10 and 11. In the figures below, P1 and P2 are the two locations equipped with pressure monitors while F is the hydrant to be flowed. No suitable C-factor testing locations were identified in Area #1 or Area #3. Testing at location #3 is located approximately 50m to the west of Area #1. The segment contains lined 250mm DI which was installed in 1990. Comparatively, Area #1 is composed of 150mm CI which was installed in 1956. All valves and hydrants related to these three C-Factor testing locations were inspected and found to be in good working order.

Figure 9: C-Factor testing Location #1


13



14


Detailed Implementation Plan - Pressure Transient Monitoring During the site visit Echologics completed on November 21st, one location for pressure transient monitoring was identified as shown in Figure 12 (circled in red). Figure 12 shows a sampling location on the combined effluent pipe exiting the Thames Centre pumping station located at approximately 2710 Dorchester Road, Dorchester, Ontario. During the site visit, it was confirmed that operators from Thames centre could install a T-fitting such that Echologics’ pressure transient monitor could be installed in addition to the sampling port. Circled in green is Thames Centre’s existing pressure monitor.


15

Figure 13: Pressure monitoring location

No other possible sites for transient pressure monitoring were identified during the site visit. Two additional locations for pressure monitoring include inside the local water tower and on the water meter at Thames Centre’s municipal offices. The feasibility of these locations will be assessed during field work on November 26th.

Confirmed Field Testing Schedule Echologics proposes the following testing schedule for the confirmed field testing dates of November 26 & 27, 2018: Monday, November 26th, 2018:

- Meet at Municipal Building – 4305 Hamilton Rd. at 10 am. - 10 am till Noon – complete two C-factor tests on Thames Crescent - 1 pm till 2 pm – complete final C-Factor test on Minnie Street - 2 pm till 3:30 pm – install transient pressure loggers at 1 to 3 sites.

Tuesday, November 27th, 2018:

- Meet at Municipal Building – 4305 Hamilton Rd. at 9 am. - Complete all segments of ePulse (total of 6 segments) – likely 3 segments in AM and 3 in PM (order

of segments yet to be arranged) - Download transient pressure loggers to ensure proper operation and readings.


16

Municipal Staff Support & Information Requests

Assistance from one Municipal staff (i.e. licensed operator) will be required during our field testing exercises on November 26 and 27, 2018. The support is needed for the following tasks:

1. Operation of hydrants and valves needed to complete C-Factor testing (i.e. installation of pressure recorders and flow meters as well as isolating appropriate valves).

2. Access to transient pressure monitoring locations and assistance with local site preparations for installation of loggers.

3. Assistance with hydrant operations for flowing noise simulations during ePulse testing.

The following information or datasets will aid in Echologics analysis and improve the accuracy of the results. If any of the following are not available, reasonable assumptions will be made based on Echologics experience with past projects of similar scope.

Calibration segment, if available (see below) Break and repair history within the survey area Pipe class or original wall thickness information Lining specifications

A calibration segment is used to calibrate the results for site specific water properties. A calibration segment should meet the following conditions:

Newly installed metallic pipe (installed within the last 5 years) Approximately 100 to 200 meters in length with valves and a hydrant Less than 16 inches in diameter Shares the same water source as the project scope

The calibration segment does not need to be the same material or diameter as the mains tested as part of the ePulse survey. If a calibration segment is not available for testing, Echologics will make reasonable assumptions based on past experience on similar projects. A discussion of the impact related to these assumptions will be included in the final report.



khalid.kaddoura

Text Box

Appendix B Echologics: Watermain Structural & Hydraulic Condition Assessment - Pilot Trials

6295 Northam Drive, Unit 1 Mississauga, ON Canada L4V 1W8 T: 905-672-echo (3246) F: 905-612-0201 Toll Free: 1 -866-echolog (324-6564)

Echologics Reference No.: 42218224

Prepared For:

Title: Watermain Structural & Hydraulic Condition

Assessment – Pilot Trials

Client: AECOM Canada Ltd.

Utility: Municipality of Thames Centre

Report Classification: Final

Date: January 10, 2019


This page is intentionally left blank


CONFIDENTIAL i Echologics Reference #: 42218224

Executive Summary

AECOM Canada Ltd. engaged Echologics, a Division of Mueller Canada (Echologics) to provide

pilot trials of watermain structural and hydraulic condition assessment services as part of their

“Water Condition Assessment and Inventory Cast Iron Replacement Needs” study for the

Municipality of Thames Centre. For these pilot trials, Echologics surveyed approximately one

kilometer of six-inch distribution main of varying materials (CI, DI & AC) for structural condition

assessment, completed three Hazen-Williams C-Factor tests for hydraulic condition assessment

and monitored water pressure and transients at two locations within the Dorchester water

distribution network. Echologics’ field personnel completed the surveys between November 26th

and December 7th 2018. Echologics performed leak detection and condition assessment using its

proprietary ePulse® methodology. C-Factors were obtained using standard hydrant flow testing

methodologies and pressures & transients were recorded for a 1-week period using high

resolution transient loggers. This report presents the information gathered from these services

including the location of suspected leaks, and the results of ePulse®, C-factor testing and pressure

transient monitoring.

Summary of key results Watermain Leak detection:

• One point of interest (POI) was discovered at the time of the survey along Minnie St. The

POI, suspected as being an actual leak, was identified as being outside of the project

study area. An attempt to pinpoint the source of the POI was made on December 7th,

however the lack of available access points such as valves and hydrants limited our ability

to confirm the exact location. It is believed that the POI or suspected leak is most likely

emanating from a watermain joint or service connection along the water main on Minnie

St, east of North St. It is recommended that an intensive acoustic survey of all service

connection curb stops be completed in order to properly locate the source of the suspected

leak.


CONFIDENTIAL ii Echologics Reference #: 42218224

Watermain Structural Condition Assessment: • One segment tested as being in good condition with less than a 10% loss in original wall

thickness.

• Three segments tested as being in moderate condition with between 10% to 30% loss in

original wall thickness.

• Two segments tested as being in poor condition with over 30% loss in original wall

thickness.

Watermain Hydraulic Condition Assessment: • A total of three C-Factors were completed on watermains of varying size and material.

• All three tests provided C-Factor well above 120 indicating that the subject watermains

have a “like new” internal roughness coefficient.

• There is no indication that internal pipe wall conditions suffer from any appreciable

tuberculation affecting watermain hydraulic capacity.

Watermain Transient Pressure Monitoring: • Two transient pressure monitors were installed for a 1-week period.

• One recorder was located at the WTP directly downstream of the system pumps and the

second was located at the base of the water tower storage facility.

• Average system pressure at the WTP is approximately 45 m (64 psi) and varies between

40 m (57 psi) when pumps are offline and 55 m (78 psi) when pumps are operating.

• Typically, there are two to three “fill and drain” cycles recorded at the water tower, which

is not believed to be excessive for this water system, indicating that the likelihood of any

large leaks existing is very low.

• There were no logged transient events during the monitoring period indicating that WTP

pump operations are operating efficiently and not creating any system transients.


Table of Contents

Executive Summary ..................................................................................................................... i

1. Project Background............................................................................................................. 1

2. Results................................................................................................................................ 4

2.1 Watermain Leak Detection ........................................................................................... 4

2.2 ePulse® Watermain Structural Condition Assessment ................................................. 6

2.2.1 Minnie Street - 6 inch main - CI, Segment 1 .......................................................... 8

2.2.2 Thames Crescent - 6 inch main - AC, Segment 2 and 3 ....................................... 8

2.2.3 Canterbury Drive - 6 inch main - AC, Segment 4 .................................................. 8

2.2.4 Sherwood Crescent - 6 inch main - DI, Segment 5................................................ 8

2.2.5 Huntington Drive - 6 inch main - DI, Segment 6 .................................................... 8

2.3 Watermain Hydraulic Condition Assessment ................................................................ 9

2.4 Watermain Transient Pressure Monitoring ..................................................................11

3. Conclusions and Recommendations ..................................................................................13

3.1 Conclusions ................................................................................................................13

3.2 Recommendations and Next Steps .............................................................................14

4 Disclaimer ..........................................................................................................................18

Appendix A Overview Maps ................................................................................................19

A.1 ePulse® Condition Assessment and Leak Detection ...................................................19

Segment 1: Minnie Street...................................................................................................19

Segment 2 and 3: Thames Crescent ..................................................................................20

Segments 4, 5 and 6: Canterbury Drive, Sherwood Crescent, Huntington Drive ................21

A.2 Hazen-Williams C-Factor Testing ................................................................................22

Appendix B Interpretation of Results ...................................................................................25

B.1 EchoWave® Leak Detection ........................................................................................25

B.2 ePulse® Condition Assessment ...................................................................................26

B.3 Limitations ..................................................................................................................32

B.4 Sensitivity Analyses and Considerations .....................................................................33


Appendix C Detailed Methodology .......................................................................................35

C.1 Leak Detection ............................................................................................................35

C.2 ePulse® Mean Minimum Hoop Thickness Testing .......................................................35

C.3 Hazen-Williams C-Factor Testing ................................................................................36

Appendix D Abbreviations ...................................................................................................39

Appendix E Glossary of Technical Terms ............................................................................40


CONFIDENTIAL 1 Echologics Reference #: 42218224

1. Project Background Thames Centre is a modern thriving municipality situated on the eastern boundary of the City of

London, Ontario. The Municipality of Thames Centre (Thames) delivered over 450,000 cubic

meters of water to over 4,800 customers in 2017. The system produces safe, high quality drinking

water for the communities of Dorchester and Thorndale. Thames retained AECOM to complete

an asset inventory and condition assessment of their water distribution network. AECOM

engaged Echologics, a Division of Mueller Canada (Echologics) to provide an initial pilot trial for

structural and hydraulic condition assessment of selected “high priority” cast iron, ductile iron and

asbestos cement water mains. Echologics utilized its proprietary ePulse condition assessment

and leak detection technology as well as completing C-Factor testing and pressure transient

monitoring.

Echologics’ primary objectives were as follows:

• Determine the average minimum structural pipe wall condition of the tested mains

• Determine hydraulic capacity and internal pipe wall condition

• Investigate the system for the existence of any potential leaks and pressure transients

To achieve these objectives, Echologics utilized its patented ePulse® technology to determine the

current structural condition of the pipe wall, while simultaneously investigating for leaks.

Echologics further conducted Hazen-Williams C-Factor testing to determine the hydraulic

capacity and internal pipe wall condition and installed pressure transient monitors at two locations

for a seven-day period. Field testing was completed between November 26th and December 7th,

2018.

AECOM developed a risk-based model to prioritized Thames Centre’s water mains. Based on

the scores of AECOM’s risk-based prioritization model, pipes with high-risk score were prioritized

for assessment. Out of selected critical pipes from the prioritization model, approximately 1 km o

piping was selected to participate in the pilot trials. Echologics conducted an initial site visit to

assess the feasibility of utilizing ePulse inspection tool, in addition to transient pressure monitoring

and C-Factor tests. Figure 1 on the following page illustrates the selected critical pipes pilot trials.



Figure 1: System Overview

Table 1 below illustrates the pipe size, material and installation dates of the sites tested.

Table 1: Sites Surveyed

Site Pipe Material Install Year

1 6” CI 1956 2 6” AC 1969 3 6” AC 1974 3 6” DI 1974



Echologics used the pipe properties shown in Table 2, which were obtained from as-built drawings

where available or assumed based on project experience.

The cast iron pipe was assumed to be Pressure Class 150 as this is the most commonly used

class in surrounding regions. Further, these cast iron pipes were assumed to be spun cast due to

their age. The ductile iron pipe was identified to be Thickness Class 52 based on record drawings

of nearby water mains. The ductile iron mains were assumed to have a 1.6 millimetre cement

mortar lining according to AWWA C104. The asbestos cement pipe was assumed to be Pressure

Class 150 based on Echologics project experience.

These assumptions have been reviewed and confirmed by AECOM and Thames Centre. It is

important to note that ePulse measured wall thickness results are independent of the nominal

wall thickness. However, incorrect nominal wall thickness assumptions will affect the percentage

loss in wall thickness results. Further details on the pipe properties are available in Appendix A:

Detailed Results. The equivalent thickness includes the nominal thickness of the pipe plus an

equivalent thickness of the lining as it contributes to the structural thickness of the pipe.

Table 2: Pipe Properties

Pipe Material Pressure Class Install Year Internal

Diameter Nominal

Thickness Lining

Thickness Equivalent

Nominal Thickness*

(in) (in) (in) (in) 6” CI PC150 1956 5.08 0.38 N/A 0.38 6” AC PC150 1969 4.68 0.66 N/A 0.66 6” AC PC150 1974 4.68 0.66 N/A 0.66 6” DI Class 52 1974 5.16 0.31 0.0625 0.34**

*Equivalent Nominal Thickness for ePulse measurements and thickness calculations **Includes the original design (metal) thickness plus an equivalent metal thickness of the cement mortar lining. In this case the 0.0625in cement lining adds approximately 0.03in of equivalent Ductile Iron thickness.



2. Results

2.1 Watermain Leak Detection

Echologics’ leak detection survey revealed one noise source point of interest (POI) captured from

among the watermains surveyed. Echologics defines a leak as a point along a pipe that is likely

losing water to the surrounding soil and environment. For a leak to be classified as discovered, a

field technician must acquire at least three pieces of unique evidence that suggest existence and

location. A POI designation indicates that some, but not all, of the criteria for a positive leak

detection result are met. A POI does not indicate a conclusive leak or no leak situation, rather it

is meant to recommend secondary investigation to either confirm the presence and location of

the leak or confirm that the acoustic anomaly was not being created from a leak. For additional

detail on these terms, please refer to Appendix B1. Echologics field personnel classified one noise

source as a POI and is relatively confident that it is in fact a suspected leak. Table 3: Leaks and

Points of Interest below contains a summary of information of this discovery. Table 3: Leaks and Points of Interest

Item ID

Leak Type

Type of leak

Estimated Size

Site Name

Segment #

Distance from Ref.

Point Reference Point

(LPM) (m)

1 POI (likely a leak)

Suspected Joint Leak or Service Leak

Unknown Minnie Street

1 (out of bracket) 0

T-joint at Minnie Street and North Street – but likely leak position is along Minnie St.

Site Reference Name: Minnie St. 6 inch diameter cast iron pipe

Segment No.: 1

Estimated Leak Size: Unknown

Location on network: 15 feet from in-line valve (DC_WCV_1543) on North street

Location notes: On North shoulder of Minnie St about 1m from the side of the road

Echologics detected a noise source at or close to the T-joint near the intersection of Minnie Street

and North Street. Using a ground microphone listening device, Echologics was not able to pinpoint

the exact location of the noise source. To confidently pinpoint the noise source to the T-joint or

further along Minnie St., Echologics must obtain three positive correlations while attaching



sensors to appurtenances on all three sides of the joint. In an attempt to pinpoint the leak location,

an Echologics field team returned to site and attached sensors to a service valve on Minnie Street

east of North Street. This proved unsuccessful due to poor sound propagation as a result of mixed

pipe materials. Due to the lack of sound propagation on Minnie Street east of North Street,

Echologics was only able to test on two sides of the joint. As such, it was not possible to determine

if the noise was originating at the T-joint or if it was coming from further East along Minnie Street.

The original segment was re-tested and the same noise was observed. As such, there is the

possibility of a leak at the T-joint or just east of the T-joint along Minnie Street. Based on the

acoustic data observed, there is strong evidence of a leak in the vicinity. It is believed that the

likely leak will be either at a joint on the watermain or on a service connection along Minnie St.

Figure 2 show where the noise appeared to be located, based on our tests.

Figure 2: Suspected leak location at the intersection of Minnie Street and North Street

Echologics recommends investigating the suspected leak further to confirm the exact location.

Possible next steps may include:

• Acoustic survey of all service connection curb stops along Minnie St. East of North St.

• Ground microphone survey during overnight period.

• Additional test points through potholing on Minnie St. East of North St.

POI



2.2 ePulse® Watermain Structural Condition Assessment

ePulse® measures the mean minimum hoop thickness of the main over the segment tested. The

technology combines acoustic data measured in the field with information about a pipe’s

manufacturing to calculate its current hoop thickness. In the testing of asbestos cement mains,

the mean remaining structural (effective) hoop thickness is the final deliverable. The pipe’s

material, internal diameter, and modulus of elasticity are all critical variables in this calculation.

The percentage of hoop thickness loss is calculated by comparing the measured thickness to the

design thickness. The results are also presented as a qualitative category indicating the expected

condition of the main. Table 4: Qualitative Categories and Color Coding shows these qualitative

condition categories. Results marked “NR” indicate that no result was attainable on a pipe

segment.

Table 4: Qualitative Categories and Color Coding

Change in Hoop Thickness

Description Colour Code Description

Metallic Pipes

Less than 10% Good Green

Minor levels of uniform corrosion or some

localized areas with pitting corrosion.

Defer / Low Priority.

10% to 30% Moderate Yellow

Considerable levels of uniform surface or

internal corrosion and/or localized areas of

pitting corrosion.

Monitor / Medium Priority.

Greater than 30% Poor Red

Significant uniform corrosion and/or

numerous areas of localized pitting

corrosion.

Address / High Priority.



The ePulse® condition assessment results are presented in Table 5 below.

Table 5: ePulse® Pipe Condition Assessment Results

Segment Street Distance Pipe Material

Internal Diameter

Equivalent Nominal

Thickness Remaining Thickness

% Change from

Nominal

(m) (mm) (mm) (mm) 1 Minnie Street 131.0 CI 150 9.7 7.3 -25 2 Thames Crescent 114.5 AC 150 16.8 12.2 -27 3 Thames Crescent 218.0 AC 150 16.8 14.6 -13 4 Canterbury Drive 78.0 AC 150 16.8 11.5 -32 5 Sherwood Crescent 219.0 DI 150 8.6 7.8 -9 6 Huntington Drive 218.5 DI 150 8.6 5.7 -34

Note: ePulse results are accurate up to 1 mm.



Echologics assessed six segments (979 meters) of water main consisting of spun cast iron, ductile

iron and asbestos cement across the Dorchester water distribution network.

2.2.1 Minnie Street - 6 inch main - CI, Segment 1

This cast iron segment on Minnie Street was the only cast iron pipe assessed in the network.

Although, this segment was identified to be in moderate condition, it is important to note that the

remaining structural wall thickness is approaching the boundary of Echologics poor condition

category. Echologics discovered a suspected leak while testing this segment. Refer to Section 2

for more information.

2.2.2 Thames Crescent - 6 inch main - AC, Segment 2 and 3

Echologics assessed two asbestos cement segments on Thames Crescent. Both segments

appear to be in moderate condition with 14% to 27% change from the nominal thickness.

Although, Segment 2 was identified to be in moderate condition, it is important to note that the

remaining structural wall thickness is approaching the boundary of Echologics poor condition

category.

2.2.3 Canterbury Drive - 6 inch main - AC, Segment 4

This asbestos cement segment on Canterbury Drive was identified to be in poor condition. It is

interesting to note that the asbestos cement water main appears to be in worse condition than

the main on Thames Crescent which was installed five years earlier.

2.2.4 Sherwood Crescent - 6 inch main - DI, Segment 5

The ductile iron segment on Sherwood Crescent was the only segment identified in good condition

with less than 10% change in structural wall thickness.

2.2.5 Huntington Drive - 6 inch main - DI, Segment 6

Although installed in the same year as the ductile iron segment assessed on Sherwood Crescent,

this ductile iron segment was identified to be in poor condition. Due to bends in the pipe layout,

Echologics estimated the segment length using a combination of measuring wheel in the field and

GIS. A 3m error in pipe length would cause a 7% error in remaining wall thickness. In order to

improve the accuracy of the reported results, detailed as-built plan and profile drawings of this

watermain would be required.



2.3 Watermain Hydraulic Condition Assessment

In order to assess the internal hydraulic condition of the watermains, Echologics completed three

Hazen-Williams C-Factor tests. The pipe C-Factor is a measure of the internal roughness of the

watermain and provides an indication of the level of tuberculation that has accumulated and

potentially affecting the hydraulic capacity of the subject watermain.

The three locations selected for the C-Factor testing were as follows:








The following table provides the key parameters and results from the C-Factor Testing. For

detailed overview of results, please refer to Appendix A.2 and for a testing methodology, please

refer to Appendix C.3

Table 6: Hazen-Williams C-Factor Test Results

Location Street Name Distance (P1 to P2)

Pipe Material

Internal Diameter

H-W C-Factor

(m) mm 1 Thames Crescent – East Flow 265 AC 150 142 2 Thames Crescent – West Flow 220 AC 150 140 3 Minnie St. – West of Clara St. 128 DI 250 128

The results above clearly indicate that the internal pipe conditions for all three sites are in “like

new” condition with no signs of tuberculation or hydraulic flow restrictions. Recommended values

for Hazen-Williams C-Factor for new Asbestos Cement pipe is 140 and for new Ductile Iron pipe

is 130.

2.4 Watermain Transient Pressure Monitoring

Echologics installed two transient pressure recorders within the Dorchester water system – one

located at the WTP directly downstream of the pumps and the second located at the base of the

water tower storage facility.

Average water pressures were recorded every 1-minute interval with a set trigger to activate

transient pressure logging at a rate of 100 times per second if a transient was detected.

The WTP location was selected due to the pump cycling required to fill the water tower under

normal demand. The water tower location, although not ideal for transient pressure monitoring,

was the only readily available second location within the distribution system. Figure 6 illustrates

the recorded average pressure at both locations between November 27th and December 6th, 2018.

The graph shows the variation in the water tower level and the corresponding pump cycles at the

WTP triggered by the level in the water tower. The Table 7 on the following page provides an

overview of the pressures recorded during this period.



Table 7: Pressure Monitoring Results

Site Location Average Minimum Maximum (m) (m) (m) 1 WTP 22.2 21.5 22.9 2 Water Tower 45.4 39.3 56.3

Figure 6: Average Recorded Pressures

Although there are several pump cycles, an average of 2 to 3 per day, none of the pump cycles

triggered the logger’s transient channel – indicating that the rate of change in the pressure was

not sufficient to be identified as a transient. The system does see a pressure surge from 40 to 55

m on average when the pump is triggered on, however the start and stop operation of these

pumps do not create any transients within the distribution system.




3.1 Conclusions

Echologics has successfully completed an assessment for AECOM on pipe wall condition, leak

detection, C-Factor testing and pressure transient monitoring on approximately one kilometer of

watermain for the Municipality of Thames Centre in Dorchester, Ontario. The main conclusions

that can be drawn from this project are as follows:

A. ePulse testing can be easily implemented within Thames Centre without the need for

excavations, external traffic control or substantial support from Thames Centre water

operators. The field-testing was completed without any interruption to service or

disruptions to Thames Centre customers.

B. The ePulse acoustic field-testing obtained results for 100% of the segments tested. No

segments tested returned a “No Result (NR)” status.

C. In addition to obtaining valuable structural condition assessment data, Echologics also

demonstrated that it could simultaneously survey the water mains for existing leaks with

the discovery of one suspected leak.

D. The ePulse testing was able to isolate 297 meters of degraded pipe with over 30% wall

thickness loss. These findings will assist Thames Centre’s replacement planning efforts,

and has demonstrated the usefulness of ePulse® condition assessment data.

E. Hydraulic condition assessment was successfully completed by implementing three

Hazen-Williams C-Factor tests. All three tests returned a C-Factor for “like new” piping

indicating that there is very little loss of hydraulic capacity within the pipeline. Furthermore,

there is no indication of tuberculation build-up in any tested lengths of pipe.

F. Transient pressure monitoring at two locations was successfully completed. The pressure

recorder at the WTP downstream of the pumps did not register any transients during the

monitoring period. This indicates that the operation of the pumps at the WTP, although

providing a measurable surge in pressure, are not creating any transients within the

distribution network.



3.2 Recommendations and Next Steps

Based on the results of the condition assessment and leak detection measurements for this

project, Echologics offers the following overall program recommendations and next steps:

A. Discuss with Echologics’ representative’s methods of incorporating ePulse® results within

Thames Centre’s future asset management program. Echologics’ experience suggests

that incorporating measurements of structural pipe wall condition into decision-making

models can improve the efficiency and effectiveness of upcoming capital improvement

programs.

B. As Echologics has assessed less than 6% of Thames’ 18 kilometers of the remaining non-

plastic network, Thames Centre may wish to consider testing the entire network to extend

the service life of pipes in good condition and allow better prioritization of their pipe

replacement program and budgets. Thames Centre may also consider pipe rehabilitation

as an option to reduce costs associated with water main replacement. Utilizing evidence

based condition assessment data is a proactive approach to asset management.

C. Echologics informed AECOM of one suspected leak located near the intersection of North

Street and Minnie Street and most likely outside of the tested segement. Echologics

recommends Thames Centre operations conduct further investigations to pinpoint the leak

location utilizing acoustic survey of all available service connection curb stops. Echologics

can also assist with the follow-up investigation related to the suspected leak and can

conduct follow up leak detection if additional sensor access points are available through

potholing.

It is important to note that structural pipe condition is one of many factors in evaluating a pipes

suitability for service, but should not be the only consideration used in replacement and deferral

decisions. Other important factors that should be considered may include pipe-loading conditions,

hydraulic capacity of the pipe, road repair/renewal schedules, consequence of pipe failure,

customer complaints, rate of decay etc. With this is mind, Echologics further recommends the

following actions for the three condition categories.



Good Condition Pipe – DEFER / LOW PRIORITY

The condition assessment results suggest the mains in this category are in good structural

condition and do not need attention in the near future unless they are under higher than normal

loading conditions. The results suggest that pipes in this category have a remaining wall thickness

within 10% of the nominal wall thickness. Echologics suggests Thames Centre continue with their

standard maintenance programs for these mains. Common industry practice is follow up condition

assessment testing in approximately 10 years depending on consequence of failure to allow

measurement of the rate of change of condition with time. If these mains require rehabilitation for

other reasons such as low pressure or poor water quality complaints, then cleaning and lining

may be an option to consider. The use and benefits of cathodic protection to slow or even stop

the “aging” process of external corrosion may also be of interest.

When interpreting ePulse® results, asset owners should understand the following:

1. Leaks can still occur on water mains with good pipe wall condition for reasons other than

pipe wall degradation, such as pressure transients, leaks at joints, leaks on service

connections, winter weather (freeze/thaw), poor installation, etc.

2. If a leak is detected on these segments, a repair should be sufficient for remediation,

because the majority of the remaining pipe wall is in good structural condition.

3. The need for future assessment of these pipes should take into account consequence of

failure. Depending on the consequence of failure, it may be beneficial to equip these

pipelines with a continuously monitoring leak detection system. For example, a non-

redundant main servicing a hospital may benefit from immediate detection of leaks as

soon as they develop.

Moderate Condition Pipe – MONITOR / MEDIUM PRIORITY

The results suggest that the pipes in this category are in moderate condition (medium priority)

and should be monitored depending on pipe loading conditions. It is important to note pipes in

this category may show a reduced capacity to withstand loading conditions, especially on pipes

that are approaching 30% loss in wall thickness.

Depending on the criticality of the main, Echologics recommends monitoring these pipes. The

following are some of possible monitoring methods:

1. For mains without an internal lining, cleaning and lining can often extend the life of

moderate condition mains as well as adding cathodic protection.



2. Regularly scheduled, traditional leak detection surveys. These are a relatively inexpensive

option capable of finding many leaks within a system. However, this method can be fairly

labor intensive and may not prevent catastrophic failures on high consequence pipelines.

3. A permanent leak monitoring system that is capable of finding most leaks on a pipeline

including small leaks before they turn into catastrophic failures.

4. A follow-up condition assessment survey to measure the rate of decay and update the

condition of the mains. A common practice is to reassess these mains in 5 years

depending on consequence of failure. An analysis of the results can be used to determine

the decay rates for these mains. The current decay rate may have an impact on the

remaining service life of the mains. Measuring this can allow for improved asset

management.

Poor Condition Pipe – ADDRESS / HIGH PRIORITY

The results indicate that pipes in this category are in poor condition and likely in need of immediate

attention. Depending on pipe loading condition, these pipes are at higher risk of experiencing

leaks and catastrophic failures and should be addressed as soon as possible. As noted above

other important factors should also be considered when preparing a remediation or replacement

plan.

In most cases, pipe segments that fall within this category have reached or are close to the end

of their useful life. Actions such as structural lining, slip-lining, and/or full replacement should be

investigated as a likely immediate requirement.

Such actions as continuous leak monitoring, cathodic protection and/or cleaning and lining will

most likely not offer tremendous value or extend the life of the water main in a cost effective

manner.

Each water network will have its own dominant degradation mechanism, as well as unique local

considerations. Echologics recommends that AECOM use the results presented in this report in

combination with other data and information available from additional services. This additional

asset information may include:

• Soil Corrosivity. This comparison will help determine if external corrosion due to

aggressive soil is a significant degradation mechanism for these mains. For example, if

corrosive soils are discovered and the main is in poor condition, the degradation is likely

related to soil conditions.



• Water Aggressiveness. This comparison will reveal whether or not the water is a

mechanism for uniform degradation. For example, aggressive water would suggest that

some of the degradation is caused from the inside; this can be assumed to cause similar

degradation rates for similar types of main.

• Break History. Collating condition assessment results and break history help identify

sections of main that are at increased risk of failure. These factors are not necessarily

related, as it is possible for pipes to have high break rates for reasons other than pipe wall

degradation.

• Consequence of Failure. Combining condition assessment results with consequence

of failure analysis is used to generate a risk assessment.

Comparing Echologics’ results with some of the aforementioned datasets, as well as investigation

will allow for AECOM and the Municipality of Thames Centre to direct their rehabilitation efforts in

a cost effective manner by creating a global rehabilitation picture which takes all sources of

degradation into consideration.



4 Disclaimer This report is intended to be used as a guide only. All forms of non-destructive testing involve an

inherent level of uncertainty. Such testing is dependent on input parameters, and outputs can be

significantly affected by variation from assumed parameters including, but not limited to, original

nominal pipe wall thickness and pipe pressure class. This report includes certain suggestions and

recommendations made by Echologics which are based on, among others, (i) the findings

included in the report, (ii) its experience and (iii) an understanding of the client’s particular

requirements. Echologics acknowledges that the client may use this report to consider potential

opportunities for pipeline replacement/rehabilitation; however, Echologics disclaims any liability

that may arise in connection with decisions based on these suggestions or recommendations or

their implementation.



Appendix A Overview Maps This section provides a detailed presentation of the project scope, as well as the data collected

and results obtained during the project.

A.1 ePulse® Condition Assessment and Leak Detection

Segment 1: Minnie Street

Figure A.1-1: Location Illustration

Table A.1-1: ePulse® Condition Assessment Results


Internal Diameter

Equivalent Nominal


% Change from

Nominal

(m) (DN) (mm) (mm) 1 Minnie Street 131.0 CI 150 9.7 7.3 -25

1



Segment 2 and 3: Thames Crescent




Internal Diameter

Equivalent Nominal


% Change from

Nominal

(m) (DN) (mm) (mm) 2 Thames Crescent 114.5 AC 150 16.8 12.2 -27 3 Thames Crescent 218.0 AC 150 16.8 14.6 -13

2

3



Segments 4, 5 and 6: Canterbury Drive, Sherwood Crescent, Huntington Drive




Internal Diameter

Equivalent Nominal


% Change from

Nominal

(m) (DN) (mm) (mm) 4 Canterbury Drive 78.0 AC 150 16.8 11.5 -32 5 Sherwood Crescent 219.0 DI 150 8.6 7.8 -9 6 Huntington Drive 218.5 DI 150 8.6 5.7 -34

4

5

6



A.2 Hazen-Williams C-Factor Testing

Location #1 – Thames Crescent – East Flow

Date Time

Location

Test performed by

Test No.

Elev. of Up-Stream Hydrant 0 m Elev. of Dn-Stream Hydrant 1.7 m

Length of Test Pipe 265 m Pipe Diameter 150 mm

Test Flow Rate No. 1 0.043851 m3/sResidual Pressure Hydrant #1 36.59 m Pipe C-Factor is 141.5Residual Pressure Hydrant #2 25.61 m

Test Flow Rate No. 2 m3/sResidual Pressure Hydrant #1 m Pipe C-Factor isResidual Pressure Hydrant #2 m



Pipe C-Factor Value (average of tests) is 141.5

Q=0.278CD2.63S0.54 Q= m3/sC=roughnessD=diameter in metresS=hydraulic gradient, metres per metrenote: spreadsheet uses mm conversion for diameter

Thames Crescent - East Flow

Alain Lalonde / Devlen Malone / Nicholas Robson

1

Hazen-Williams C-Factor Testing Worksheet

Test Pipe

Note: All cross-connection valves must be closed.

26-Nov-18 11:30 AM

Hydrant #1Up-Stream

Hydrant #2Down-Stream

Hydrant #3Flow

Flow Direction

Hydrant #1Up-Stream


Hydrant #3Flow

Flow Direction



Location #2 – Thames Crescent – West Flow

Date Time

Location

Test performed by

Test No.

Elev. of Up-Stream Hydrant 0 m Elev. of Dn-Stream Hydrant -3 m








Thames Crescent - West Flow


2


Test Pipe


26-Nov-18 12:00 PM

Hydrant #1Up-Stream


Hydrant #3Flow

Flow Direction

Hydrant #1Up-Stream


Hydrant #3Flow

Flow Direction



Location #3 – Minnie St. – West of Clara St.

Date Time

Location

Test performed by

Test No.

Elev. of Up-Stream Hydrant 0 m Elev. of Dn-Stream Hydrant 0.8 m








Minnie St. - West of Clara St.


Test Pipe


26-Nov-18 1:35 PM


3

Hydrant #1Up-Stream


Hydrant #3Flow

Flow Direction

Hydrant - P1Up-Stream

Hydrant- P2Down-Stream

Hydrant - FFlow

Flow Direction



Appendix B Interpretation of Results

B.1 EchoWave® Leak Detection

When Echologics discovers a noise on a main, it can be classified as a leak or a point of interest

(POI). If further investigation reveals negative results, it is classified as no leak discovered. Within

all Echologics reports, if no mention is made of leaks on a given section, it may be assumed that

the result of the test is no leak discovered.

No Leak Discovered When a negative correlation is matched with poor coherence, it is concluded that no leak was

detected. In effect, there is no indication of a noise source of any sort, and therefore that there is

no other evidence of leakage. Where possible, leak simulations are performed to confirm the

absence of leaks and to ensure equipment functionality.

Point of Interest (POI) A Point of Interest (POI) designation indicates that some, but not all, of the criteria for a positive

leak detection result are met. This could mean that a strong correlation is observed but coherence

is poor, or that there is no confirmation of leak noise through other test methods such as ground

sounding or secondary correlation tests. This does not indicate a conclusive leak; however, it is

recommended that AECOM/Thames perform a secondary investigation. This will confirm the

presence and location of the leak, as there is evidence of some form of noise inside the pipe.

Leak Three pieces of conclusive evidence must be acquired for a Point of Interest to be upgraded to a

Leak. This includes but is not limited to the following methods of detection:

• leak correlation

• ground sounding

• acoustic sounding of fittings

• visual observation of moving water

• confirmation of chlorine residuals in stagnant water

Several criteria must be met for audio recordings in order to provide a positive leak detection

result. This includes but is not limited to:

• a clean distinctive correlation peak & an observable coherence level

• similar frequency spectra in each channel



• a minimum amount of clipping in the time signal

In some instances, more than one correlation test can be used as evidence to conclusively identify

a leak. For instance, a field specialist can perform multiple correlation tests with sensors mounted

to different pipe fittings.

B.2 ePulse® Condition Assessment

ePulse® condition assessment measures the mean minimum hoop thickness (for asbestos

cement or metallic mains) or mean hoop stiffness (for reinforced concrete). Where the original

nominal thickness (or stiffness) is available, results are also presented as a percentage loss, and

as a category indicating a qualitative description of the expected condition of the main.

Qualitative Condition Description Categories The color-coding and descriptions in Table B.2-1: Color Coding and Hoop Thickness Loss

Qualitative Descriptions are used for the results presented in all ePulse® condition assessment

reports.

Table B.2-1: Color Coding and Hoop Thickness Loss Qualitative Descriptions

Change in Hoop

Thickness Description

Color Code

Description

Asbestos Cement Mains Metallic Mains

Less than

10% Good Green

Minor levels of degradation and/or

isolated areas with minor loss of

structural thickness

Minor levels of uniform

corrosion or some

localized areas with pitting

corrosion.

10% to

30% Moderate Yellow

Considerable levels degradation

and loss of structural thickness.

Moderate levels of cement leeched

away from asbestos matrix.

Considerable levels of

uniform surface or internal

corrosion and/or localized

areas of pitting corrosion.

Greater

than 30% Poor Red

Significant degradation and loss of

structural thickness. Substantial

levels of cement leeched away

from asbestos matrix.

Significant uniform

corrosion and/or numerous

areas of localized pitting

corrosion.



These descriptions are based on Echologics’ experience and with validation of results through

the exhumation of pipe samples tested. Following the table, more detail is provided as to the

expected condition of different types of main in each condition category, along with examples of

validation of the ePulse® method on each type of main.

Distribution of Degradation within Segments Each ePulse® result represents an average condition within a segment between two sensor

attachment points. Pipe conditions may vary within a segment. The condition at any one point

within the segment may not reflect the average conditions within that segment.

The ePulse® method tests the mean minimum hoop thickness of the pipe, which is not the same

as the average thickness of the pipe. ePulse® measures a pipe’s hoop stiffness: its resistance to

axi-symmetric expansion under the tiny pressure variations caused by sound waves. Material

properties are then used to calculate the hoop thickness which would provide exactly this

stiffness. This is referred to as the mean minimum hoop thickness.

To obtain this same value mechanically, you would need to: divide a pipe into hoops; measure

the thinnest section of structural material around the circumference of each hoop (i.e. graphite,

tuberculation product, or asbestos cement with the calcium leached out would not be counted);

and then average these.

For example, any of the following descriptions will hold true for a pipe with a loss of 25%:

1. Circumferentially uniform loss of 25% along the entire segment.

2. Circumferentially uniform loss of 50% along half of the segment, but 0% loss along the

other half of the segment.

3. Loss of 25% at the crown of the pipe along the entire segment, but 0% loss along any

other point in the circumference along the entire segment.

These descriptions hold true for asbestos cement, metallic and reinforced concrete mains.

Condition Interpretation in Asbestos Cement Mains As asbestos cement pipes age and degrade, they will not lose physical thickness, but will lose

structural (or effective) thickness as the calcium leaches out of the asbestos cement matrix. This

portion of the asbestos cement will become soft, and will no longer bear a structural load, and

therefore does not contribute to the structural thickness. The ePulse® method measures the

remaining structural hoop thickness (also known as the effective hoop thickness), as illustrated in



Figure B.2-1, rather than the actual physical hoop thickness (which will generally remain at the

nominal hoop thickness).

Figure B.2-1: Structural Hoop Thickness in Asbestos Cement Pipe

Condition Interpretation in Metallic Mains Corrosion can occur in metallic pipes either in a localized area or in a generalized manner along

the main. Examples of various levels of corrosion are presented in Figure B.2-5 below.

Most of the degradation is often caused by a combination of internal corrosion, soil

aggressiveness and coating defects on the surface of the main. If no coating was present upon

installation, then the degradation would be due to soil aggressiveness alone.

For cement mortar lined pipes, areas with higher losses may indicate the lining has been

degraded to the point that the water column is now in contact with the metal, locally accelerating

the degradation rate. This may also suggest that the soil loading conditions were such that the

pipe experienced an over-deflection during its lifetime, causing damage to the interior lining.

When considering the water aggressiveness as a mechanism for corrosion, it can be assumed

that the degradation is relatively uniform across the length of the main. If pipes are unlined (bare),

internal degradation may be attributed to a combination of localized pitting, and the formation of

tuberculation that can also be accompanied by the formation graphitic corrosion (leaching of iron

from the metal matrix).



Localized corrosion is most likely due to isolated mechanisms such as direct current corrosion, or

localized aggressive soil conditions. For cement lined pipes, areas with higher losses may indicate

the lining has been degraded to the point that the water column is now in contact with the metal,

locally accelerating the degradation rate.

Figure B.2-2: Examples of Different Levels of Corrosion in Metallic Pipe

6” CI pipe with 4.2% measured loss

6” CI pipe with 10% measured loss

6” CI pipe with 47% measured loss

18” CI pipe with 18.5% measured loss



Validation

As of the February 2016, a total of 104 ePulse® validation results have been provided to

Echologics by our clients or third parties. Some clients have requested confidentiality; however,

we are able to present the result in aggregate.

Figure B.2-3: ePulse® Validations On All Materials

Figure B.2-4: ePulse® Validations On All Iron Pipes (left) and Asbestos Cement Pipes (right)



Two factors are worth attention in the charts. The R2 value is known as the coefficient of

determination. This provides a measure of how well validation results are predicted by ePulse®

results. It is the proportion of total variation of outcomes in validation results explained by the

ePulse® results. An R2 of 1 indicates that the data match perfectly, while an R2 of 0 indicates that

the ePulse® results cannot be used to predict the validated results at all. For non-destructive

testing methods, an R2 value above 0.5 represents strong predictive power.

The correlation coefficient R is the square root of the R2 value. For example, an R2 value of 0.5

means the same thing as a correlation of 0.71.

The equation (y = α + βx) indicates how well calibrated the ePulse® measurements are, on

average. Values of α close to zero, and of β close to 1, indicate good calibration. For non-

destructive testing methods, a β greater than 0.5 and an α less than 25% of the average value

represent good calibration.

Note that the variation between the ePulse® results and validation measurements is not the same

thing as the error in the ePulse® results. It is actually the combination of the error in the ePulse®

results and the random variation in point samples versus the true average.

Comparing ePulse® results to the results of validations will over-estimate the actual error in the

ePulse® results. The reason for this is that the ePulse® results are averages over segments of

about 100 m (300 ft.) in length, whereas the validation results indicate the thickness at a one point

or a small sub-segment. Each validation measurement will have a random error versus the true

average over that segment. The difference between an ePulse measurement and a validation

measurement can be understood as:

ePulse® - Validated = (ePulse® – True_Average) + (True_Average – Validated)

Even if the ePulse® results perfectly match the true average (ePulse® – True_Average = 0), we

would still expect to see a difference between validation results and ePulse®:

ePulse® - Validated = (True_Average – Validated)

Actual pipe conditions will vary randomly along the sample, so the difference between the true

average and validation results should be a normal distribution centered around zero. If ePulse® is

effectively measuring the true average, we should see the same pattern in the difference between

the ePulse® and Validated results. The actual distribution is shown in Figure 3, and appears to

match the expected pattern.



Figure B.2-5: Variance between ePulse® results and validation results

There are a small number of outliers, which likely represent errors in those ePulse®

measurements. The remainder of the data match the expected normal distribution.

B.3 Limitations

The accuracy of the final results presented in this report can be impacted by a certain factor. The

following are some of the factors that affect the accuracy of results.

Modulus of Elasticity The modulus of elasticity of the pipe material is one of the factors in the calculation of the mean

minimum hoop thickness. While Echologics has significant experience estimating the modulus of

elasticity based on the material, age, and region of manufacture, we can improve the accuracy of

the results by testing the actual modulus of elasticity of an exhumed sample of the pipe.

Pipe Specifications Detailed pipe specifications were not available for all pipes surveyed. Although Echologics has

made reasonable assumptions for internal diameter, material and original nominal thickness, the

results can be improved if accurate pipe specifications can be provided. If original specifications

cannot be located, AECOM/Thames may wish to exhume a pipe coupon to verify diameter,

material and thickness assumptions.



Statistical Variation The values generated by ePulse® testing are averaged for a segment of pipe which ranges in

length from 150 feet to 500 feet. This averaging allows for the possibility of having small lengths

within the segment which are severely degraded. This degradation will not be shown in the final

result. Therefore, it is important to note that the value presented describes the general condition

of the pipe and may not show future potential point failures.

B.4 Sensitivity Analyses and Considerations

Several variables may affect accurate analysis:

• Inaccurate distance measurements

• Variance in manufacturing tolerances

• Variance in the modulus of elasticity of the material

• Unknown pipe repairs

• Inadequate correlation signals.

Echologics is constantly committed to reducing error during every step of the testing process.

Distance Measurement An accurate distance measurement is crucial for an accurate assessment. In general, a 1% error

in distance measurement can result to more than a 2% error in final percentage of thickness lost.

For this reason, our preference is to use potholes or in-line valves, as these provide the most

accurate distance measure, since it is a point-to-point measurement. As the number of bends

and/or elevation changes between the sensor connection points increases, so does the potential

error in the distance measurement.

Pipe Manufacturing Tolerances Small differences in nominal specifications will occur between pipes due to differences in

manufacturers and tolerances. These differences commonly range from between 5% and 10%

depending on the manufacturer and the material. Furthermore, a contractor may have installed a

pipe that exceeds the minimum specifications. Under these circumstances the measurements

may show a pipe with a hoop thickness that is greater than expected. This is particularly true of

older pipes as their tolerances were not adhered to as strictly.

The material properties used for calculations are selected using conservative estimates. This

provides for a worst-case scenario analysis.



Repair Clamps on Previous Leaks Acoustic waves are primarily water borne. As such, a small number of repair clamps will have an

insignificant effect on the test results, since the acoustic wave will bypass the clamps.

Modulus of Elasticity A change in elastic modulus of 10% will cause a change in the calculated thickness by

approximately 10%. The elastic modulus is known for common materials used in the

manufacturing of pressure pipe, but this value can vary among manufacturers. It is dependent on

the manufacturing process and the quality of the material. The material properties used for

calculations are selected using conservative estimates. This provides for a worst-case scenario

analysis.

Unaccounted for Replacement of Pipe Sections during Repairs Acoustic waves propagate differently depending upon the pipe material. This effect remains true

for unaccounted for short pipe replacements with different materials, and can result in significant

error. For example, a new 6-meter-long (~20 feet) ductile iron repair in a 100-meter-long (~328

feet) cast iron pipe section of average condition, will produce a small error of +3.5% in measured

hoop thickness. However, the same repair made with PVC pipe would produce an error of -41%

in measured hoop thickness.

Preferably, pipe sections selected for testing should be free of repaired sections. However, if this

condition does not exist, the impact of the repaired pipe section can be accounted for, provided

accurate information is available for the age, location, length, material type, and class of the repair

pipe section.

Inadequate Correlation Signals Inadequate correlation signals can sometimes occur in the field. The following are some of the

conditions that may cause an inadequate correlation:

1. The presence of plastic repairs in metallic pipes which can cause poor propagation of

sound.

2. Loose or worn components in fittings used for the measurements, such as valve or hydrant

stems.

3. Large air pockets in the pipe which heavily attenuate acoustic signals.

4. Heavily tuberculated pipe, particularly old cast iron or unlined ductile iron pipes, which can

attenuate the acoustic signals to such an extent that a correlation is of very low quality.



Appendix C Detailed Methodology

C.1 Leak Detection

The methodology employed is known as the cross-correlation method. A correlator listens

passively for noise created by a leak. If one is detected, it uses the time delay between sensors

to determine the position of the leak. The following procedure was used to conduct the leak

detection survey:

1. For each location surveyed, the distance between the sensors was measured.

2. Sensors were mounted either directly on the pipe or were connected to the water column

with hydrophones.

3. A correlation measurement was performed without introducing noise (known as a

background recording), and the signal was saved to the computer so that further analysis

could be performed off-site. A preliminary analysis is performed on-site to determine if any

leaks are present.

C.2 ePulse® Mean Minimum Hoop Thickness Testing

A section of pipe is the length bracketed by two contact points on the main. An out-of-bracket

noise source is located outside of that segment. A known noise source may be used to determine

the acoustic wave velocity in a segment of pipe. Knowing the distance between the sensors, the

acoustic wave velocity (v) will be given by v = d/t, where d is the length of pipe between the

sensors, and t is the time taken for the acoustic signal to propagate between the two sensors.

The following procedure is followed to conduct an ePulse® data collection survey:

1. A leak detection survey is performed on the length of pipe to check for the presence of

existing leaks. (Described in previous section)

2. A noise source is created “out-of-bracket”. A variety of different noise sources can be used

including an existing leak noise, blow-off noise, pump noise, impulse noise, running a fire

hydrant, tapping on a fire hydrant, or directly on the pipe.

3. A new correlation measurement is performed and stored as a wave file for further analysis

and confirmation off-site. Data is analysed further to obtain an optimum correlation,

ensuring an accurate velocity measurement.



Wave Velocity Equation

The general form of the acoustic pipe integrity testing equation is shown below. Equation C.2-1: Wave Velocity - Thickness Model

v : measured velocity

v0 : propagation velocity in an infinite body of water

Di : pipe internal diameter

Kl : bulk modulus of the liquid

E : elastic modulus of the pipe material

tr : residual thickness of the pipe

Bulk Modulus of Water Calibration

Different water sources often produce a different bulk modulus of water. The bulk modulus

essentially represents the water’s inherent resistance to compression, and is impacted by factors

like water temperature, dissolved salts and entrained air. Echologics’ field specialists calibrate the

bulk modulus at each water company’s water source. This requires performing a single test on a

stretch of pipe with a known pipe condition. In practice, this generally means performing an

additional test on a new section of pipe that has been installed within the past few years.

C.3 Hazen-Williams C-Factor Testing

Echologics utilizes the industry standard flow and pressure monitoring equipment to ensure a

highly accurate and repeatable flow test. The following is a short description of the equipment

and procedure used in order to complete C-Factor Testing.

Flow & Pressure Monitoring Equipment

Pressure – high-resolution pressure recorders (0.1m (0.14 psi) resolution with 0.25% accuracy)

are used for recording the static & dynamic pressures from the pressure hydrants, and pitot

pressures from the flow hydrant. All logging is done at a 10-second logging interval. The pressure

loggers permit the pressures to be averaged over the test period to ensure the most accurate C-

Factor calculation is obtained.

𝑣𝑣 = 𝑣𝑣𝑜𝑜 ×�1

�1 + �𝐷𝐷𝑖𝑖𝑡𝑡𝑟𝑟� × �𝐾𝐾𝑙𝑙𝐸𝐸 ��



Flow – The Pollard hydrant flow diffuser & pitot assembly is used to complete the flow monitoring.

The pitot gauge is a stationary gauge ensuring consistent repeatable pitot measurements. The

pitot pressure is recorded using a pressure logger and a visual reading can also be obtained from

the pressure gauge. The pitot pressure is converted to a corresponding flowrate using a standard

formula.

Level – The pressure hydrant elevation difference is calculated directly from the static pressure

readings from the pressure loggers. Actual elevation of the measuring points is not needed for

an accurate C-Factor calculation, rather accurate elevation differential is needed and the pressure

recorders offers this with a resolution of 0.1 m at 0.25% accuracy which is more then sufficient for

an accurate C-Factor calculation.

Distance Measurement – A standard calibrated measuring wheel will be used to measure the

distance between the pressure hydrants. This provides sufficient accuracy for an accurate C-

Factor calculation.

The following schematic highlights the typical setup for a C-Factor Test.



Detailed Testing Procedure for C-Factor Testing

In order to complete a successful test, the following field procedure will be utilized for each test:

1. Confirm Flow Test monitoring locations with Municipal Staff.

2. Confirm Flow Test schedule with Municipal Staff.

3. Measure distance between pressure monitoring points with measuring wheel.

4. Close required valves to isolate test section, if required. (Municipal Staff will complete all

valving).

5. Install Pressure Recorders at required pressure monitoring points prior to testing to obtain

static pressure readings. (Static pressure readings will provide elevation difference between

monitoring points.)

6. Install Pollard flow testing assemblies on appropriate flow hydrant.

7. Install Pressure Recorders on Pollard pitot assemblies to record pitot pressures.

8. Close both control gate valves of the flowmeters connected to the 2 ½” ports and open hydrant

fully. Slowly open one control gate valve. Let valve flow full open for 5 minutes and then open

second control gate valve and let it flow full open for 5 minutes. Close one control valve and

then the other – slowly.

9. Remove all equipment, download data and reopen closed valves.

10. Complete C-Factor calculation using the Echologics spreadsheet program.

Data Analysis & Reporting

All data recorded in the field will be converted to a spreadsheet format for graphing and averaging

purposes. A master spreadsheet with all C-Factor data will be compiled. All C-Factor calculations

are completed using the latest version of the Echologics C-Factor calculation spreadsheet.



Appendix D Abbreviations

AC Asbestos Cement: Pipe wall construction consisting of asbestos cement.

CI Cast Iron: Pipe wall construction consisting of cast iron. This includes pipes classified as pit cast iron or spun cast iron as well.

CL Concrete lined: Indicates whether or not a specific pipe type has some form of concrete lining. This abbreviation will typically follow a pipe type abbreviation Ex: DICL for ductile iron concrete lined.

DI Ductile Iron: Pipe wall construction consisting of ductile iron.

GIS Geographic Information System: A system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.

GPS Global Positioning System: a global system of satellites used to provide precise positional data and global time synchronization.

OOB Out-of-Bracket. Please refer to the technical glossary.

PCI Pit Cast Iron: Pipe wall construction consisting of pit cast iron.

POI Point of Interest. Please refer to the technical glossary.

PVC Poly Vinyl Chloride: Pipe wall construction consisting of poly vinyl chloride.

SCI Spun Cast Iron: Pipe wall construction consisting of spun cast iron.



Appendix E Glossary of Technical Terms Acoustic Wave Speed

Also known as: wave speed, wave velocity, velocity. The speed at which a coupled-mode pressure wave travels along a pipe.

Blue/White Station

A piece of equipment where a sensor is connected to transmit the data to a central location. Typically stations are colour coded blue or white.

Coherence Measure of similar vibration frequency between two channels (Blue and White stations or a node pair).

Correlation The process of comparing two acoustic signals for similarity in the time domain. Echologics technologies use correlation to judge the time delay between two signals. This allows for determination of the location of leaks along a pipeline.

In-Bracket A noise source that is within the span of pipe between two Stations or Nodes.

Leak Discovered

A point along a pipe that is likely losing water to the surrounding soil and environment. For a leak to be classified as discovered, a field technician must acquire at least three pieces of unique evidence that suggest existence and location.

No Leak Discovered

No evidence of leakage was discovered or a POI was under investigate and it was determined that it was not a leak.

Node A piece of equipment where a sensor is connected to transmit the data to a central location. Typically nodes are paired with other nodes as part of a large array installed on a pipeline or in an area.

Out-of-Bracket

A noise source that is outside the span of pipe between two Stations or Nodes.

Point of Interest

Evidence of some form of noise or energy on the pipe. There is not enough evidence to classify a point of interest as a leak.

Segment A section of pipe surveyed in one measurement. The length of the segment is the distance between two sensors.

Sensor A device used to measure physical or chemical properties of a system. In the context of this report this term will be typically used as a reference to a vibration sensor.

Site A neighbourhood or area within which a segment of pipe exists.


Appendix C

Likelihood of Failure Map

(Dorchester) -Echologics Results





aecom.com



Technical Memorandum #5: Levels of Service Water Condition Assessment and Inventory Cast Iron Replacement Needs

Prepared by: Prepared for:



Date: January 2020

Project #: 60586191


Distribution List



Revision History

Rev # Date Revised By: Revision Description 1 February 27, 2019 Khalid Kaddoura Initial Draft 2 July 05, 2019 Michele Samuels Draft Submission 3 January 20, 2020 Michele Samuels Final Submission


AECOM The Municipality of Thames Centre Technical Memorandum #5: Levels of Service

Water Condition Assessment and Inventory Cast Iron Replacement Needs

TM5_2020-01-30_Level Of Service_60586191_V3.Docx



















Authors

Report Prepared By:

Khalid Kaddoura, PhD, PMP, EIT

Asset Management Consultant

Report Reviewed and Approved By:

Michele Samuels, M.Eng., MBA, P.Eng.

Sr. Asset Management Consultant/Project Manager






1. Introduction ....................................................................................... 1



2. Defining Levels of Service ................................................................ 3

2.1 What Are Levels of Service? ................................................................................... 3

2.2 The Context of Water Network Management .......................................................... 3

2.3 Methodology and Approach .................................................................................... 4

2.3.1 The National Water and Wastewater Benchmarking Initiative................................. 4

2.3.2 Workshops ............................................................................................................. 5

3. Developing ‘Minimum Levels of Service’ ......................................... 6

3.1 Regulations and Best Practices .............................................................................. 6

3.1.1 Drinking Water Systems (Ontario Regulation 170/03)............................................. 6

3.1.2 Ontario Drinking Water Quality Standards (Ontario Regulation 169/03) ................. 6

3.1.3 Drinking Water Testing Services (Ontario Regulation 248/03) ................................ 6

3.1.4 Asset Management Planning for Municipal Infrastructure (Ontario Regulation 588/17) ................................................................................................................... 7

3.2 Best Practices ......................................................................................................... 7

3.2.1 Distribution Systems: Design Guidelines for Drinking-Water Systems .................... 7

3.2.2 Procedure for Disinfection of Drinking Water in Ontario .......................................... 8

4. Levels of Service Framework ............................................................ 9

4.1 Workshop Results ................................................................................................... 9

4.1.1 Goal #1 - Provide Reliable Service and Infrastructure ............................................ 9 4.1.1.1 Sub-goal #1 – Reliable Distribution System ...................................................... 9 4.1.1.2 Sub-goal #2 – Proactive Maintenance Management ......................................... 9 4.1.1.3 Sub-goal #3 – Emergencies Responded to With Defined Procedures ............. 12

4.1.2 Goal # 2 – Meet Service Requirements with Economic Efficiency ........................ 13

4.1.2.1 Sub-goal # 1 – Municipality Meets Service Requirements ............................... 13 4.1.2.2 Sub-goal # 2 – Optimized Performance of Infrastructure ................................. 14

4.1.3 Goal # 3 – Protect the Environment ...................................................................... 16 4.1.3.1 Sub-goal # 1 – Water Distribution Incorporates Conservation

Considerations ............................................................................................... 16 4.1.3.2 Sub-goal # 2 – Leaks Estimate in Water System ............................................ 16

4.1.4 Goal # 4 – Provide a Safe and Productive Workplace .......................................... 17 4.1.4.1 Sub-goal # 1 – Safe Workplace ...................................................................... 17 4.1.4.2 Sub-goal # 2 – Productive Workplace ............................................................. 18

4.1.5 Goal # 5 – Satisfied and Informed Customers ...................................................... 18

4.1.5.1 Sub-goal # 1 – Informed Customers ............................................................... 19 4.1.5.2 Sub-goal # 2 – Satisfied Customers ............................................................... 19





4.1.6 Goal # 6 – Protect Public Health and Safety ......................................................... 21 4.1.6.1 System Flushing at a Velocity Appropriate to Address Water Quality .............. 21 4.1.6.2 Samplings to Comply with Regulatory Policies ............................................... 21

5. Level of Service Summary .............................................................. 23

6. Conclusions and Recommendation ............................................... 25

7. References ....................................................................................... 26

List of Figures Figure 1: The Link Between Activities, KPIs, and "Customer Related LoS" – An Example .................................... 3 Figure 2: National Wastewater Benchmarking Initiative Goal Model ..................................................................... 4 Figure 3: Number of Main Breaks/100 km Length – NWWBI .............................................................................. 11 Figure 4: % of Valves Cycles – NWWBI ............................................................................................................ 11 Figure 5: % of Hydrants Inspected or Winterized – NWWBI ............................................................................... 12 Figure 6: Number of Service Connection Repairs and Replacements/Number of Service Connections –

NWWBI .............................................................................................................................................. 13 Figure 7: Cost of Main Break Repairs as % of Total O&M Cost – NWWBI ......................................................... 15 Figure 8: Volume of Non-Revenue Water in L/Connection/Day – NWWBI .......................................................... 15 Figure 9: Infrastructure Leakage Index – NWWBI .............................................................................................. 17 Figure 10: Number of O&M Accidents with Lost Time/1,000 O&M Labour Hours – NWWBI ................................. 18 Figure 11: Number of Water Pressure Complaints by Customers/1,000 People Served – NWWBI ....................... 20 Figure 12: Target Response Time for Emergencies – NWWBI............................................................................. 20 Figure 13: Target Response Times for Non-Emergencies - NWWBI .................................................................... 21

List of Tables Table 1: Goals, Sub-goals and Performance Measures ...................................................................................... 5 Table 2: Ontario Regulation 588/17 Deadlines ................................................................................................... 7 Table 3: Design/Maintenance Requirements and Operational Indications ........................................................... 8 Table 4: Secondary Disinfection Benefits, Minimum and Maximum Requirements .............................................. 8 Table 5: Thames Centre Breaks per 100 km .................................................................................................... 10 Table 6: Provide Reliable Service and Infrastructure ........................................................................................ 23 Table 7: Meet Service Requirements with Economic Efficiency ........................................................................ 23 Table 8: Protect the Environment ..................................................................................................................... 23 Table 9: Provide a Safe and Productive Workplace .......................................................................................... 24 Table 10: Satisfied and Informed Customers ...................................................................................................... 24 Table 11: Protect Public Health and Safety ........................................................................................................ 24

Appendices Appendix A. Workshop #2 Minutes of Meeting




TM5_2020-01-30_Level Of Service_60586191_V3.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 60 km of watermain infrastructure (about 2 km of watermains are privately owned) to supply water and provide management services to approximately 7,500 residents connected to the Dorchester and Thorndale municipal drinking water system. The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2 (Statistics Canada, 2017). Unlike wastewater and/or stormwater collection systems, pressurized watermains are often cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing watermains in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF). Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess pressurized watermains. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition of watermain infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing inspections to minimize risk exposure while optimizing budgetary allowances. On this basis, pressurized watermains can be managed through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based state of good repair program to:

1. Prioritize and assess watermains; 2. Analyze pipe lifecycle; and 3. Provide an annual funding forecast.

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with the procedures and tools to prioritize watermains for inspections including the means to assess existing pipe material inventory and prioritize these inspected watermains for renewal in the short-, mid-, and long-term. The primary objective of this study is to develop a maintenance renewal schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-tasks including, but not limited to, the following:

1. Reviewing inventory data; 2. Identifying failure modes and distress indicators; 3. Developing a Consequence of Failure (CoF) model, including prioritizing pipes for assessment;





4. Matching suitable inspection technologies, and planning a pipeline condition assessment trial for a critical watermain previously identified by the risk model;

5. Interpreting inspection findings to estimate the likelihood of failure (LoF); 6. Defining the level of service; and 7. Building a comprehensive risk-based decision matrix for pipe renewal.

1.2 Objectives for Technical Memorandum #5 Technical Memorandum No. 5 (TM #5) is designed to develop the Levels of Services (LoS) Framework for the Municipality of Thames Centre’s water distribution system. The goals of this report are as follows:

1. Establish an understanding of Levels of Service; 2. Review current regulatory requirements and best practices for management of water linear assets; 3. Define the current LoS provided by the Municipality (at a utility level not at a customer level); 4. Define the desired LoS by incorporating industry best practices and regulatory requirements; 5. Set the stage for defining desired maintenance activity levels; and 6. Establish performance measures that can be used to monitor progress and achievement.

This memo summarizes the results of this task; namely to outline the Municipality’s current and desired levels of service.





2. Defining Levels of Service

2.1 What Are Levels of Service? Typically, the term Level of Service (LoS) is used to describe the quantification of benefits that a municipal customer receives from municipal services from the perspective of the municipal customer. The term “services” is specifically used here, because most customers will have little or no interest in individual assets. They instead focus on the service outcomes they receive from the infrastructure. By defining the LoS, a customer can expect, the Municipality can then define specific activities they can engage in to provide or meet the desired service. By making a commitment to a given LoS, the Municipality is also implicitly committing to employ a given amount of Municipality’s resources to actualizing this LoS. The level of funding and resources used in managing water linear assets should be directly tied to the defined LoS. Defining LoS and subsequent activity targets are excellent communication tools for establishing funding levels, as customers and asset owners gain an understanding of how customer service can be related to use of government resources. Trade-offs can then be made as performance or spending becomes unpalatable. When resources are limited, LoS can be established as a compromise between the minimum and desired LoS, with the understanding that additional resources would be required to improve the agreed upon LoS. In theory, the Municipality could identify various LoS (minimum, existing, higher etc.) and determine the cost of providing each of these LoS. The Municipality could then have an informed discussion with residents and business owners to determine their desired LoS and their willingness to pay for the desired LoS. This discussion is particularly important when considering water network funding needs. In defining the Municipality’s LoS, the underlying goal is to identify gaps between the current and desired LoS, and quantify the changes needed to actualize the Municipality’s goals; including the required changes in lifecycle activities or performance and the associated cost.

2.2 The Context of Water Network Management Levels of Service are related to activity targets but are not the same (Figure 1). For instance, a resident may be dissatisfied with any unplanned water service interruption. There are many activities that the Municipality could undertake to reduce unplanned service interruptions:

◼ Perform planned condition assessment to understand the existing state of the infrastructure ◼ Conduct the required maintenance and rehabilitation requirements to avoid sudden failures

Figure 1: The Link Between Activities, KPIs, and "Customer Related LoS" – An Example





2.3 Methodology and Approach

2.3.1 The National Water and Wastewater Benchmarking Initiative

Through the National Water and Wastewater Benchmarking Initiative (NWWBI), AECOM and participating municipalities have identified a generic goal model for municipal services. The goal model sets the framework for identifying LoS for a Water Utility (Figure 2).

Figure 2: National Wastewater Benchmarking Initiative Goal Model Using the approach of defining an overall goal, understanding the underlying sub-goals and how one would measure the achievement of a sub-goal, the development of a utility level LoS framework can be taken from broad overall goals down to the specific measures of performance that will drive achievement. Table 1 provides a listing of the sub-goals and measures to be employed in developing the water utility’s LoS framework for each water network service area. The advantage of using the NWWBI framework is that examples of current performance by Canadian Municipalities participating in Benchmarking may be provided. Note that these metrics are graphed throughout the discussion of LoS Findings, and that all labels identifying the municipality have been removed (display of identifiers are limited to Benchmarking participants).





Table 1: Goals, Sub-goals and Performance Measures

Goal Sub-Goal Performance Measure Provide Reliable

Service and Infrastructure

Reliable Distribution System Do design criteria match applicable current standards (e.g., AWWA)? Are design criteria reviewed on a cycle?

Proactive Maintenance Management

Is a condition assessment plan in place to monitor and gather data on the system? Number of Main Breaks Per 100 km Percent of Valves Cycled Percent of Hydrants Inspected and Winterized Are service outages planned proactively? Are failures documented and analyzed using Root Cause Analysis? Preventative and Corrective Maintenance Hours / System Length

Emergencies Responded to With Defined Procedures

Are Contingency plans defined and rehearsed for typical failures as well as critical assets? Does the Municipality maintain agreements with contractors for the standard operating procedures in response to unplanned outages? Number of Emergency Service Connection Repairs / Number of Service Connections Do operators maintain an inventory of spare parts matched to the specifications of the assets?

Meet Service Requirements with Economic

Efficiency

Municipality Meets Service Requirements

Regulatory requirements achieved for operating pressures and fire flow?

Optimized Performance of Infrastructure

Condition assessment plan is based on risk profiles and deployment costs. Cost of Main Break Repairs as % of Total O&M Cost Volume of non-revenue water per connection per day

Protect the Environment

Water Distribution Incorporates Conservation Considerations

Non-Revenue Water in L/Connection/Day

Leaks Estimate in Water System

System Length Tested for Leakage Infrastructure Leakage Index / Operating Index

Provide a Safe and Productive

Workplace

Safe Workplace Are health and safety plans in place as part of standard operating procedures? Are regulatory requirements for O&M achieved (MTO Book 7 for Traffic Control, Occupational Health and Safety Act, etc.) Number of hours dedicated to safety training per year.

Productive Workplace Are activities defined and controlled using SOPs? # of O&M Accidents with Lost Time / 1,000 O&M Labour Hours Overtime hours paid as a result of emergency repairs

Satisfied and Informed

Customers

Informed Customers Are customer-facing staff knowledgeable of the assets, common issues, and customer questions? Does the municipality educate the public through outreach efforts? Does Council endorse the Levels of Service proposed for O.Reg 588/17 compliance?

Satisfied Customers # of Water Pressure Complaints by Customers / 1,000 People Served Target Response Times for Emergencies and Attainment Target Response Times for Non-Emergencies and Attainment

Protect Public Health and

Safety

System Flushing at a Velocity Appropriate to Address Water Quality

Cumulative Length Cleaned as % of System Length Cumulative Length Cleaned

Samplings to Comply with Regulatory Policies

Is a sampling program in place? What are the requirements followed for sampling? Sampling locations?

2.3.2 Workshops

Using the model framework developed through the NWWBI, AECOM drafted potential goals, sub-goals, and performance measures customized for the Municipality’s water distribution system. Through discussion with the Municipality’s staff, the tables were refined and existing LoS were identified where possible. Appendix A contains the meeting minutes for the relevant workshops.





3. Developing ‘Minimum Levels of Service’

Minimum Levels of Service (LoS) describe the minimum achievement the Municipality must deliver through its water distribution management as directed by regulations, and directives from corporate leadership or Council members. There are several constraints and requirements that steer how the Municipality conducts water distribution management. Compliance with Provincial and Federal regulations is required to avoid fines, legal action, or loss of funding opportunities; meaning that compliance must always be ensured as the minimum. These realities inform the development of the minimum LoS that the Municipality recognizes it must accomplish. Only with this understanding can the use of resources be evaluated as focus shifts to seeking savings opportunities or delivering on a desired LoS beyond the minimum requirement. Minimum LoS provides the baseline for these discussions.

3.1 Regulations and Best Practices

3.1.1 Drinking Water Systems (Ontario Regulation 170/03)

This document provides insights into minimum requirements that each water distribution owner is required to follow to ensure safe drinking water is supplied and delivered to customers (Ontario, 2018a). The document is divided into several schedules that are related to treatment equipment, sampling, operational checks, and testing. In general, the schedules outline:

◼ Expected sampling frequencies; ◼ Sampling locations; ◼ Microbiological sampling and chlorine residual requirements; ◼ Form of samples; ◼ Continuous monitoring and other testing requirements.

Minimum requirements in the schedules, in many cases, depend on the treatment methodologies adopted by each municipality. Therefore, comprehensive minimum thresholds based on the Regulation can be derived after studying the drinking water system as a whole (distribution system as well as treatment plants).

3.1.2 Ontario Drinking Water Quality Standards (Ontario Regulation 169/03)

This document lists quality standards required to be attained to produce acceptable drinking water quality (Ontario, 2018b). The act contains several schedules that define Microbiological Standards, Chemical Standards and Radiological Standards.

3.1.3 Drinking Water Testing Services (Ontario Regulation 248/03)

Under this regulation, the Municipality is required to perform tests in specific laboratories. Any laboratory that performs drinking water testing should have a license and accredited for the tests they conduct (Ontario, 2018c). The Municipality should ensure laboratories used have the minimum requirements mentioned in the regulation.





3.1.4 Asset Management Planning for Municipal Infrastructure (Ontario Regulation 588/17)

In December 2017, the Province of Ontario passed a regulation titled, Asset Management Planning for Municipal Infrastructure, under the Infrastructure for Jobs and Prosperity Act (2015), to regulate asset management planning for municipalities. There are several key deadlines with requirements for asset management planning, including requirements for formalized LoS by July 1, 2024, accompanied by a financing strategy for funding the activities that achieve the LoS. Table 2 provides deadlines along with the regulatory requirements related to Ontario Regulation 588/17.

Table 2: Ontario Regulation 588/17 Deadlines

Deadline Date Regulatory Requirement Additional Information

July 1st 2019 All Municipalities are required to prepare their first Strategic Asset Management Policy.

The Strategic Asset Management Policy must be reviewed and, if necessary, updated at least every five (5) years.

July 1st 2021 All municipalities are required to have an Asset Management Plan for its entire core municipal infrastructure.

Assets under Core Municipal Infrastructure include: water, wastewater, stormwater, roads, bridges and culverts.

July 1st 2023 All municipalities are required to have an asset management plan for infrastructure assets not included under their core assets.

Other assets not identified in the Core Assets above.

July 1st 2024 All Asset Management Plans must include information about the levels of service that the municipality proposes to provide, the activities required to meet those levels of service, and a strategy to fund activities

3.2 Best Practices

3.2.1 Distribution Systems: Design Guidelines for Drinking-Water Systems

The chapter on Distribution Systems in the Design Guidelines for Drinking-Water Systems provides requirements to follow in designing a water distribution system that balances water quality and water network performance (Ontario, 2016). The minimum and maximum requirements defined in the document shall be followed when designing new assets. During operation, any variations in specific parameters could indicate deficiencies in the water distribution system. Table 3 provides some of the design/maintenance requirements for a distribution system along with some of the operational insights related to each item.





Table 3: Design/Maintenance Requirements and Operational Indications

Item Design Operation Maintaining Water

Quality Maximize turnover and minimize retention times and water age

Owners should perform the minimum sampling requirements to ensure water quality is not deteriorated. Reported aesthetic parameters could be an indication of some material deterioration (i.e., red water may indicate internal corrosion in metallic pipelines)

Operating Pressure Operating pressure to be designed for minimum of 20 psi and maximum 100 psi

The normal operating pressure in the distribution system shall be between 50 and 70 psi. Water pressure complaints could be an alert of some water distribution operating pressure problems

Transient Pressure Watermains shall be designed to withstand operating pressure and induced transient pressure

Pipelines that do not have a minimum capacity to withstand transient pressures could lead to failure in pipelines

C-Factor The design should consider the minimum AWWA requirements

C-Factor could be an indication of deterioration. In Asbestos Cement pipelines, values that exceed the original C-Factors are indications of internal deterioration. In metallic pipelines, however, values that are less than the original values could be an indication of tuberculation in pipelines

Material Selection Some of the requirements when selecting pipe material are related to trench foundation, location, soil conditions, etc.

Unaccounted loads and improper bedding requirements could impose stresses that lead to failure. Soil condition is another crucial parameter. Corrosive soil could lead to excessive external deterioration and lead to pipeline failure

Flushing Flushing devices shall provide a minimum velocity of 0.8 m/s to flush watermains

As the main aim of flushing is to maintain water quality and increase capacity of the distribution system, flushing at lower velocity rates would not attain the main objectives

Corrosion Where aggressive soil conditions are suspected, some analysis are required to be performed. Metallic material used shall be protected

Corrosive soil will lead to deterioration of the external surface of unprotected metallic pipelines. Upon metallic pipeline failure and extraction of a sample coupon, external deterioration could indicate corrosive soil.

3.2.2 Procedure for Disinfection of Drinking Water in Ontario

This procedure is intended to provide systematic methodologies related to water disinfection and pre-disinfection that may be required for an effective disinfection process (Ontario, 2018d). The procedure contains requirements that are related to water treatment plants but also provides requirements for distribution systems. The specific provision in the regulation for the distribution system is as follows:

“all drinking water entering a distribution system that has been treated and is otherwise ready for consumption must contain a disinfectant residual that persists throughout the distribution system unless a point of entry treatment approach is used as permitted by the Regulation”.

Table 4 shows the benefits of providing secondary disinfection in water distribution systems along with the minimum and maximum parameter requirements. It should also be noted that disinfection of drinking water systems is required after constructions or repairs. The disinfection process for watermains shall be in accordance with the AWWA Standard for Disinfecting Water Mains (C651).

Table 4: Secondary Disinfection Benefits, Minimum and Maximum Requirements

Item Benefits Minimum Maximum Disinfectant

Residual Maintenance (secondary

disinfection)

Protect water from microbiological re-contamination reduce bacterial re-growth control biofilm formation Indicator of distribution system integrity

Free chlorine residual of 0.05 mg/L at pH 8.5 or lower or dioxide residual of 0.05 mg/L or where monochloramine is used, a combined chlorine residual of 0.25 mg/L

chlorine residual <=4.0 mg/L, when measured as free chlorine <=3.0 mg/L when measured as combined chlorine





4. Levels of Service Framework

This section provides the Levels of Service (LoS) framework for the Municipality’s water distribution system. This section is structured to provide a detailed description of the current, minimum, and desired LoS for each goal using the methodology outlined in Section 2.3.1, consideration of regulatory requirements, and discussions during Workshop #2.

4.1 Workshop Results On February 14th, AECOM and the Municipality held a workshop to establish current practices taken by the Municipality and the goals and directives driving the future. AECOM received feedback on the potential goals, sub-goals, and performance measures for the Municipality’s system. Through discussion with the Municipality, the framework was refined, and key issues were identified. Workshop notes and minutes are provided in Appendix A.

4.1.1 Goal #1 - Provide Reliable Service and Infrastructure

This goal describes the sub-goals required to be achieved and maintained to ensure that the Municipality’s water distribution system is reliable and is attaining the objective in distributing safe drinking water to customers. This is measured using three sub-goals:

1. Reliable Distribution System 2. Proactive maintenance management 3. Emergencies responded to with defined procedures

4.1.1.1 Sub-goal #1 – Reliable Distribution System

Providing reliable infrastructure is a result of construction, rehabilitation, and repair of water infrastructure according to accepted standards and protocols. This sub-goal ensures that built infrastructure is based on accepted standards and requirements of the American Water Works Association (AWWA). These standards set certain procedures and design requirements in more than 180 AWWA codes that are related to storage, treatment and distribution of all areas of water treatment and supply. As these standards are updated and developed regularly based on technology advancement, it is significant to ensure that the Municipality is aware of the updated standards. The Municipality has an engineering design standard that was established in 1989. The standard includes certain design criteria for multiple assets including sewers, water, roads, etc. Currently, the Municipality utilizes the City of London’s engineering standards for activities that require certain regulated requirements and procedures such as the installation of new watermains. To enhance the Levels of Service of this sub-goal, the Municipality is planning to allocate funding to establish a new design standard for the Municipality that is compliant with Ontario and current practices regulations.

4.1.1.2 Sub-goal #2 – Proactive Maintenance Management

Due to asset ageing and other influencing factors, watermains are subject to deterioration. Therefore, proper maintenance programs and plans are essential to provide proactive maintenance to help minimize sudden collapses and breaks that can disrupt communities. As the pipe condition is an essential input for a reliable maintenance plan, assessment of existing pipelines shall be performed to ensure critical pipelines are identified and





actioned before failing. Thus, the Municipality shall inspect the condition of pipes for perforations, tuberculation, and other conditions related to structural integrity and hydraulic capacity and use the records to plan for maintenance. The Municipality can achieve this goal by:

1. Developing a condition assessment plan to monitor and gather data on the system; 2. Recording the number of breaks 3. Recording the number of valves cycled and hydrants inspected and winterized 4. Ensuring that outages are proactively planned 5. Documenting failures and conducting Root Cause Analysis 6. Recording hours used for preventative and corrective maintenance

In the past, the Municipality mostly followed reactive maintenance procedures to maintain water infrastructure – “fix it when it breaks”. More recently, the Municipality has moved towards proactive watermain maintenance that is dependent on age. The most commonly performed approach is to replace pipelines considered old when compared to certain thresholds that the Municipality uses for different material types. Another recent proactive approach that the Municipality follows is considering the age of the pipelines along with the number of breaks and/or recorded complaints for intervention decisions. Although some unplanned corrective actions have been recorded, the Municipality stated that the number of such interventions where minimal when compared to proactive maintenance activities. Currently, the Municipality does not conduct any root cause analysis to understand main factors leading to failure. However, some subjective and visual observations are recorded. The Municipality will maintain existing procedures related to this sub-goal. However, the Municipality should perform root cause analysis to record actual failure causes. The Municipality can also record information related to coupon samples as demonstrated in TM#2: Initial Criticality Findings.

Maintenance Performance Monitoring

Figure 3 through Figure 5 provide insights regarding performance measures of participating municipalities in the National Water and Wastewater Benchmarking Initiative (NWWBI). These metrics are valuable for assisting the Municipality with monitoring certain maintenance activities in comparison to its peers. Figure 3 illustrates the number of main breaks per 100 km of watermain for NWWBI participants over a single reporting year. Table 5 shows the number of breaks per 100 km of length to compare the Municipality’s results with other Canadian municipalities. The ratio was calculated based on the reported number of breaks using 2007-2016 data. Notably, all breaks occurred in Dorchester, averaging approximately 6 breaks per 100 km over the studied interval. At a network level, the average ratio was approximately 5 breaks per 100 km, which is aligned with the average ratios of many participating NWWBI municipalities.

Table 5: Thames Centre Breaks per 100 km

Year Dorchester Length (km)

Thorndale Length (km)

Network Length (km)

Number of Breaks

Breaks per 100 km

(Dorchester)

Breaks per 100 km

(Thorndale)

Breaks per 100 km

(Network) 2007 39 7 47 1 3 0 2 2008 39 7 47 1 3 0 2 2009 41 7 48 3 7 0 6 2010 42 11 53 4 10 0 8 2014 43 13 56 3 7 0 5 2015 43 13 56 1 2 0 2 2016 43 14 57 4 9 0 7





Figure 3: Number of Main Breaks/100 km Length – NWWBI

Figure 4: % of Valves Cycles – NWWBI





Figure 5: % of Hydrants Inspected or Winterized – NWWBI For other maintenance related examples, we can look at valve cycling and hydrant maintenance. The Municipality cycles valves in the distribution system annually. This exceeds the performance of most NWWBI participants (Figure 4) and could represent an opportunity to reduce efforts in this area providing that asset reliability and availability is not affected. With regard to water features maintenance programs, the Municipality inspects hydrants annually which is compliant with Ontario Regulation 388/97 and aligns with the performance of many NWWBI participants (Figure 5).

4.1.1.3 Sub-goal #3 – Emergencies Responded to With Defined Procedures

Infrastructure is exposed to a variety of threats that may result in system disruption and failure which would require reactive maintenance. Therefore, the Municipality shall have contingency and response plans established to resolve and complete reactive interventions with minimized disruptions. To achieve this sub-goal, the Municipality should have:

1. Contingency plans for typical and critical failures; 2. Defined procedures for repairs; 3. Agreements with contractors to resolve unplanned maintenance; 4. Spare parts inventory that matches existing infrastructure and specifications; 5. Records of the number of emergency service connection repairs.

Currently, the Municipality follows established Standard Operating Procedure(s) (SOPs) to perform activities related to reactive maintenance such as watermain breaks. The in-house procedures provide sequential steps for commonly observed failures (repetitive) as well as those related to critical assets (high criticality in the opinion of the Municipality). The Municipality maintains certain critical spare parts in their inventory that can be used in reactive maintenance. These spare parts have similar specifications with existing water infrastructure. In the event of watermain failure, the O&M team isolate the affected main to minimize disruptions and/or water quality deterioration. Concurrently, the team communicates with contractors with whom they have informal agreements to fix breaks. In their records, the Municipality maintains service connection repairs that were conducted along with major associated costs.





The Municipality will continue procedures followed in responding to reactive interventions as it is believed that these procedures are not causing disruptions to residents. To guarantee long-term availability of local contractors in reactive interventions (fixing breaks), it is recommended to establish formal agreements with them. Using Figure 6, the Municipality can compare their calculated indicators with participating NWWBI municipalities. The indicator is a percentage of the number of service connection repairs and replacements to the total number of service connections.

Figure 6: Number of Service Connection Repairs and Replacements/Number of Service Connections – NWWBI

4.1.2 Goal # 2 – Meet Service Requirements with Economic Efficiency

This goal measures the economic efficiency of the Municipality’s water distribution system operations. It is measured by two sub-goals as follows:

1. Municipality meets service requirements 2. Optimized performance of infrastructure

4.1.2.1 Sub-goal # 1 – Municipality Meets Service Requirements

Water distribution systems are designed to deliver safe drinking water to customers and provide water for fire protection. Therefore, the Municipality shall ensure that the system designed and constructed can deliver the maximum-day demand and fire flow for individual and public demands. The Municipality shall evaluate flows with tools such as hydraulic modelling and develop corrective action plans to be implemented when deficiencies are identified. The Municipality can achieve this sub-goal by following regulatory requirements for operating pressures and fire flow stated in the design guidelines.





Currently, the operating pressure in the water distribution system of the Municipality is well above the minimum required by regulation (20 psi). In fact, the normal operating pressure stated in the design guidelines (50 psi to 70 psi) is maintained by the Municipality. The Municipality did not receive system operating pressure-related complaints. The Municipality developed a new hydraulic model simulating the existing infrastructure on March 2019. The Municipality will continue maintaining existing operating pressures.

4.1.2.2 Sub-goal # 2 – Optimized Performance of Infrastructure

During the service life of the water infrastructure, several activities are performed such as data collection, condition assessment, intervention plans, etc. These activities play an important role in establishing robust infrastructure asset management. In general, municipalities are required to carry out many of these activities to ensure a well-performing system. However, municipalities may confront difficulties in allocating budgets for needed activities. Therefore, it is recommended that the Municipality use optimized models that better allocate funds to enhance existing water distribution system activities. The optimized models may help to minimize costs and failures and maximize performance and benefits. The Municipality can achieve this by:

1. Developing and applying a condition assessment plan based on risk profiles and deployment costs; 2. Monitoring the cost of main break repairs and comparing it with the total O&M Cost 3. Recording the volume of non-revenue water

As mentioned in Section 4.1.1.2, the Municipality follows reactive maintenance practices with regard to watermain breaks. To avoid such interventions and increase proactive activities, the Municipality contracted with AECOM to provide a robust condition assessment plan that was based on a staged-approach classification matrix. The methodology adopted incorporated risk parameters that included the likelihood of failure (LoF) and the consequence of failure (CoF). For more information about the risk model and the condition assessment staged-approach, please refer to TM#3: Condition Assessment Plan and Recommended Assessment Methods. In most cases, the Municipality records major invoices of certain repairs. However, there is no specific threshold for whether an invoice is recorded or not. As part of the non-revenue water calculation, the Municipality compares the water pumped with the used (revenue) water upon distribution. As a point of reference, Figure 7 and Figure 8 show the two performance measures of participating municipalities in the NWWBI program, which are related to this sub-goal. The first figure compares the cumulative costs of main breaks repairs with total O&M costs. The second figure is an indicator of the volume of non-revenue water per connection per day. In the figure, apparent losses relate to water that is being consumed but not being paid for due to water theft and/or billing errors and real losses relate to water that is lost due to leakage.





Figure 7: Cost of Main Break Repairs as % of Total O&M Cost – NWWBI

Figure 8: Volume of Non-Revenue Water in L/Connection/Day – NWWBI





4.1.3 Goal # 3 – Protect the Environment

This goal describes the goals and measures the Municipality can take through water distribution management to protect the environment. The Municipality can achieve the following goal by:

1. Incorporating considerations for conservation within the water distribution system; 2. Estimating leaks in the water system.

4.1.3.1 Sub-goal # 1 – Water Distribution Incorporates Conservation Considerations

Water treatment plants require significant energy to produce clean, safe drinking water that is compliant with relevant regulations. Due to leaks in water pipelines, some treated water is lost, and energy used to treat and convey such water is thereby wasted. The Municipality should have a maximum annual target for water loss and should have documentation defining the calculation procedure for such an amount. The Municipality should always aim to minimize water loss to maintain an efficient system. The Municipality can achieve this sub-goal by:

◼ Estimating the volume of non-revenue water per connection per day, shown previously (Figure 8) The Municipality has a threshold of 10% between the pumped treated water and the non-revenue water. On average, the Municipality has maintained the same rate over recent years. The Municipality will continue to monitor non-revenue water and ensure that it is within the Municipality’s threshold. Another initiative for water conservation, the Municipality has established a water rate consumption program. The current water service charge including the first 14 m3 is $34.11. The rate is set to $1.86 per m3 for the next 15 to 50 m3 of consumption. Beyond 50 m3 of consumption, the rate increases to $2.53 per m3. These rates apply to commercial and residential units.

4.1.3.2 Sub-goal # 2 – Leaks Estimate in Water System

The Municipality should have a system for estimating (quantifying) leakage on an annual basis. The Municipality can achieve this sub-goal by performing a leak detection program and recording the length tested for leakage. In 2013, the Municipality of Thames Centre hired a contractor to conduct a leak detection program for the existing water distribution system. According to interviewed personnel, the vendor did not capture any leakage during the inspection. However, in the recent condition assessment pilot that was conducted by Echologics using ePulse, the vendor suspected a leak (see TM#4 – Inspection Plan and Findings). Further investigations were recommended as confirmation of the leak required some civil/mechanical work. The Municipality only estimates water loss or non-revenue water by comparing pumped water with used/revenue water. Other than the leak detection program performed in 2013, the Municipality did not conduct any further leak detection investigations. With the 10% water loss rate that the Municipality is maintaining, the Municipality will continue monitoring the system and conduct further investigations if any increase in this rate is observed. Currently, the Municipality does not have information regarding the infrastructure leakage index. It is also recommended to use the infrastructure leakage index as an indicator to compare its performance with NWWBI participating municipalities (refer to Figure 9).





Figure 9: Infrastructure Leakage Index – NWWBI

4.1.4 Goal # 4 – Provide a Safe and Productive Workplace

The Municipality shall ensure that operation and maintenance activities of the water distribution system are performed using safe and productive practices and procedures. This goal is measured by two sub-goals:

1. Safe Workplace 2. Productive Workplace

4.1.4.1 Sub-goal # 1 – Safe Workplace

Personnel performing work affecting distribution system operation shall be competent based on appropriate education, training, skills, test requirements, and experience as required by the governing regulatory agency. The Municipality should endeavour to evaluate procedures and processes used by workers with the intent of optimizing their operation. The O&M team in the Municipality of Thames Centre are aware of relevant health and safety procedures. The Municipality has an annual emergency management procedure in which several emergency scenarios are physically simulated. Additionally, the Municipality provides health and safety induction sessions for new members as well as training related to confined spaces. Prior to any field work, O&M team members perform tailgate meetings and ensure personal protection equipment (PPE) is used. Further, traffic arrangements are sub-contracted during watermain breaks to provide safe workspaces during repair. However, the Municipality has inventory for traffic safety arrangements (flags and cones) that are usually used before contractors reach watermain break sites.





The Municipality is allocating funds to buy equipment that can be used in confined spaces when needed. The Municipality plans to continue offering existing safety training programs.

4.1.4.2 Sub-goal # 2 – Productive Workplace

The Municipality shall establish written maintenance procedures that document all functioning and maintenance activities required for the distribution system. The Municipality is achieving this sub-goal by:

◼ Having well-established SOPs for operational activities;

◼ Monitoring the number of O&M accidents with lost time that will impact the productivity of the O&M team. A comparison can be made with the participating municipalities in the NWWBI program (refer to Figure 10).

◼ Recording emergency repairs that are completed as part of overtime working hours. The Municipality stated that they will continue with existing efforts to make certain a productive workplace is in-place.

Figure 10: Number of O&M Accidents with Lost Time/1,000 O&M Labour Hours – NWWBI

4.1.5 Goal # 5 – Satisfied and Informed Customers

Under this goal, the Municipality wishes to ensure customers are satisfied with the service that the water distribution system provides. This is measured by the following:

1. Informed Customers 2. Satisfied Customers





4.1.5.1 Sub-goal # 1 – Informed Customers

The Municipality of Thames Centre has designated personnel who respond to customer questions and complaints. Most commonly, customers complain by directly calling the Municipality or by sending emails. The Municipality responds to all questions and complaints related to water systems the same day they arise. However, most of the complaints are driven by plumbing issues rather than the water distribution system itself. The Municipality records all associated complaints in their database. Currently, the Municipality does not have an outreach program to educate the public on the water distribution system. As an effort to enhance engaging the public, the Municipality is working on updating its website to include information regarding watermain breaks and other issues related to the water system. The Municipality will continue addressing complaints as they arise and develop techniques to engage residents.

4.1.5.2 Sub-goal # 2 – Satisfied Customers

The Municipality shall ensure that customers are satisfied with supplied water in terms of pressure, taste, quality, colour, and odour. The Municipality can achieve this requirement by:

◼ Recording the number of water quality and pressure complaints as they arise. The Municipality is currently experiencing water quality issues from the Thorndale area. It is believed that the problem is a result of the source well. The Municipality also had a past experience of several instances of water quality issues from a particular resident. However, O&M staff checked the tap water and suspected no quality issues based on visual observation. Furthermore, all pressure complaints have been related to internal plumbing and not the Municipality’s system operating pressure. As complaints are recorded in the database, the Municipality can compare its records with other participating municipalities in the NWWBI program using Figure 11.

◼ Targeting response times for emergency and non-emergency incidents. The Municipality ensures that service outages are completed within a short period of time on a case by case scenario. During outages, door-to-door discussions are held to discuss any concerns with customers. In addition, the Municipality sends fliers to customers along with the water bill to give notices to residents with regard to any proactive maintenance to be performed. The Municipality can compare its target response time performance with some other participating municipalities in the NWWBI program using Figure 12 and Figure 13.

The Municipality will continue providing existing services as, based on current knowledge, it is believed that customers are satisfied with the Municipality’s efforts.





Figure 11: Number of Water Pressure Complaints by Customers/1,000 People Served – NWWBI

Figure 12: Target Response Time for Emergencies – NWWBI





Figure 13: Target Response Times for Non-Emergencies - NWWBI

4.1.6 Goal # 6 – Protect Public Health and Safety

4.1.6.1 System Flushing at a Velocity Appropriate to Address Water Quality

The Municipality implements a systematic flushing program that meets the needs of the utility, taking into consideration the condition of the system, hydraulic capacity, water quality, and other site-specific criteria. The Municipality cleans the entire distribution system twice a year for the Dorchester and Thorndale areas. The Municipality will continue the existing flushing and cleaning program that is agreed with the Ministry office to maintain distribution water quality from the treatment plant to service connections/plumbing systems.

4.1.6.2 Samplings to Comply with Regulatory Policies

The Municipality collects samples from treatment and plumbing systems but not from hydrants or any other water features. The Municipality stated that the samples are tested for residual chlorine and microbiology per Ontario Regulation 170/03). In general, sampling requirements depend on water treatment methodologies as well as the source of water and other factors described in Ontario Regulation 170/03. Since this project was solely related to the distribution system (excluding treatment plants), determining minimum requirements based on the Regulation’s schedules would be difficult. However, in some schedules under Ontario Regulation 170/03, lead testing would specifically be related to distribution systems (higher contents of lead in the plumbing systems would negatively impact customers). For example, and based on Schedule 15.1, a municipality that provides drinking water for a population of 3,300 to 9,999 would have a minimum number of sampling points as follows (lead testing-related):

◼ Number of sampling points in plumbing that serves private residences = 40 ◼ Number of sampling points in plumbing that does not serve private residences = 4 ◼ Number of sampling points in distribution system = 8





According to Ontario Regulation 170/03 and since the Municipality of Thames Centre’s water distribution system serves 7,500 people (as per the Municipality), the applicable schedules would be Schedules 1, 6, 7, 10, 13, 15.1,16, 17, 22, 23, and 24. Specific minimum requirements shall be outlined in the provincial Drinking Water Works Permit and License.





5. Level of Service Summary

Table 6: Provide Reliable Service and Infrastructure

Goal # 1 – Provide Reliable Service and Infrastructure Sub goal Performance Measure Existing Desired LoS Category Recommendation

Reliable Distribution System

• Meet provincial requirements

• The Municipality has an established design standard since 1989. The standard includes design criteria for multiple assets including sewers, water, roads, etc.

• The Municipality will prepare its own standard for future infrastructure construction projects

• Provincial requirements • Follow best practices and requirements set by AWWA; comply with Ontario government requirements

Proactive Maintenance Management

• Failure records • In general, the Municipality follows reactive-based interventions. In some cases, they use a screening approach based on age, number of breaks, and number of complaints to perform interventions.

• The Municipality cycles the valves annually. Also, the hydrants are inspected annually

• The Municipality will maintain existing procedures and O&M practices.

• O&M • Perform root cause analysis on coupon samples from failed pipe and record attributes of collected data. Update breakage GIS database with collected information.

• Maximize proactive maintenance to avoid catastrophic failures which lead to high reactive costs.

Emergencies Responded to With Defined Procedures

• Number of emergency service connection repairs

• Currently, the Municipality follows established Standard Operating Procedure(s) (SOPs) to perform activities related to reactive maintenance such as watermain breaks.

• The Municipality maintains certain critical spare parts in their inventory that can be used in reactive maintenance

• The Municipality will continue procedures followed in responding to reactive interventions as it is believed that these procedures are not causing disruptions to residents.

• O&M • Ensure spare parts inventory data is updated so that parts are available when needed.

• Revise SOPs that would optimize performance based on lessons learned

Table 7: Meet Service Requirements with Economic Efficiency

Goal # 2 – Meet Service Requirements with Economic Efficiency Sub goal Performance Measure Existing Desired LoS Category Recommendation

Municipality Meets Service Requirements

• Pressure requirements • The Municipality maintains minimum operating pressure requirements

• The Municipality will continue maintaining existing operating pressure

• Provincial requirements • Maintain system operating pressure between 50 - 70 psi

Optimized Performance of Infrastructure

• Compare cumulative costs of main breaks repairs with total O&M costs

• The Municipality follows reactive maintenance practices with regard to watermain breaks.

• The Municipality records major invoices of certain repairs

• The Municipality recently contracted with AECOM to provide a risk-based framework to better allocate annual budgets. The Municipality will continue updating repair costs

• Planning • Apply and update risk-based model and utilize it to maintain optimized maintenance of linear infrastructure. It is recommended to keep track of all costs and expenses for minor and major repairs.

Table 8: Protect the Environment

Goal # 3 - Protect the Environment Sub goal Performance Measure Existing Desired LoS Category Recommendation

Water Distribution Incorporates Conservation

Considerations

• Estimate volume of non-revenue water per connection per day

• The Municipality has a threshold of 10% between pumped treated water and non-revenue water. On average, the Municipality has maintained the same rate over recent years.

• The Municipality will continue to monitor non-revenue water and ensure that it is within the Municipality’s threshold.

• Planning & O&M • The Municipality is encouraged to minimize nonrevenue water threshold

Leaks Estimate in Water System

• Infrastructure Leakage Index

• Recently, the Municipality did not perform a leak detection program. The Municipality infer leaks through non-revenue water

• The Municipality will continue to monitor non-revenue water and ensure that it is within the Municipality’s threshold.

• O&M • Ensure that a leak detection program is part of the O&M plan. Based on leak detection results, the Municipality could intervene, accordingly. Estimate infrastructure leakage index





Table 9: Provide a Safe and Productive Workplace

Goal # 4 - Provide a Safe and Productive Workplace Sub goal Performance Measure Existing Desired LoS Category Recommendation

Safe Workplace • Incidents with lost time • The O&M team is aware of relevant health and safety procedures.

• The Municipality allocates funds to enhance safety in the workplace and reduce accidents. The Municipality will continue offering safety training programs

• Planning & Policy • Update procedure whenever accidents happen, if applicable. Such updates would improve safety considerations. Record number of lost hours due to field accidents.

Productive Workplace • Total available field and lost hours

• The Municipality has SOPs that are believed to maintain a productive workplace. The Municipality keeps some records of field working hours including overtime.

• The Municipality stated that they will continue with existing efforts to facilitate a productive workplace.

• Planning & Policy • Maintain a productive workplace by following established SOPs. Perform required training that aims at enhancing performance.

Table 10: Satisfied and Informed Customers

Goal # 5 - Satisfied and Informed Customers Sub goal Performance Measure Existing Desired LoS Category Recommendation

Informed Customers • % of customers informed about water services

• The Municipality has designated personnel who respond to customer questions and complaints. Currently, the Municipality does not have an outreach program to educate the public on the water distribution system.

• As an effort to enhance engaging the public, the Municipality is working on updating its website to include information regarding watermain breaks and other issues related to the water system. The Municipality will continue addressing complaints as they arise and develop techniques to engage residents.

• Planning • Increase customer water network knowledge. Continue addressing customer questions as they arise

Satisfied Customers • Number of complaints (pressure and water quality)

• Target response time for emergencies

• Target response time for non-emergencies

• Respond to complaints as they arise. The Municipality is currently experiencing water quality issues/complaints from the Thorndale area

• The Municipality will continue providing existing services as it is believed that customers are satisfied with current efforts.

• Planning & O&M • Collect water samples when investigating quality issues/complaints; Conduct laboratory testing rather than relying on visual observations

Table 11: Protect Public Health and Safety

Goal # 6 - Protect Public Health and Safety Sub goal Performance Measure Existing Desired LoS Category Recommendation

System Flushing at a Velocity Appropriate to Address Water Quality

• Annual cleaned total length

• The Municipality implements a systematic flushing program that meets the needs of the utility, taking into consideration the condition of the system, hydraulic capacity, water quality, and other site-specific criteria

• The Municipality will continue existing flushing and cleaning program that maintains distribution water quality from the treatment plant to service connections/plumbing systems.

• O&M • Maximize flushing and cleaning lengths to minimize water quality issues.

Sampling to Comply with Regulatory

Policies

• Meet Provincial requirements

• The Municipality collects samples from treatment and plumbing systems but not from hydrants or any other water features.

• The Municipality will continue existing sampling program and frequency

• O&M • Continue complying with Ontario Regulation 170/03.





6. Conclusions and Recommendation

In the context of asset management, understanding and optimizing operations and maintenance (O&M) serves as a critical component of managing the asset portfolio. Good maintenance planning and maintenance management is a vital component of asset management. Ultimately, an infrastructure system such as the Municipality’s water distribution system requires O&M activities that achieve the minimum or desired Level of Service. Beyond these primary objectives, operations and maintenance should be executed in a cost-effective manner. Formalizing an optimal O&M program is the practice of analyzing, defining, and monetizing O&M practices that will actualize LoS objectives. Completed successfully, annualized savings will accrue from all or some of the following:

1. Reduced cost of individual work orders through better planning and execution.

2. Reduced levels of overtime and premium pricing of equipment and materials.

3. Maximize economic return from assets through their entire expected life cycle.

4. Better overall utility management, as past year results feed directly into the forecasting of workloads and budgets for the future.

The findings of the Levels of Service framework demonstrated that in many areas the Municipality is already achieving its desired Level of Service or is on track to do so. In areas where there are opportunities for improvement within these goals, there is already some progress underway or issues that are well recognized by the Municipality. Additional considerations can also be followed for future Levels of Service improvements:

1. Develop and implement a leak detection program to understand existing vulnerabilities in watermains. The condition assessment pilot conducted under this assignment suspected a leak along a watermain on Minnie Street, east of North Street;

2. Perform root cause analysis on failed watermain sections to aid in protecting other assets from similar causes of failure;

3. Develop performance monitoring metrics and occasionally benchmark against peer municipalities.

4. Record qualitative and quantitative information pertaining to collected coupon samples as demonstrated in TM #2: Initial Criticality Findings – Table 4.2. It is recommended to maximize the collected data depending on the watermain material type. Some of the relevant information are related to the pipeline attributes while others are related to the surrounding environment (soil);

5. Record invoices for all repairs to keep track of the spent budget and unit costs for budgeting purposes;

6. Develop and implement a condition assessment plan and a rehabilitation/replacement optimized model to minimize budgets and maximize performance.





7. References

Ontario, 2016: Design Guidelines for Drinking-Water Systems. Retrieved from https://www.ontario.ca/document/design-guidelines-drinking-water-systems-0

Ontario, 2018a: DRINKING WATER SYSTEMS. Retrieved from https://www.ontario.ca/laws/regulation/030170

Ontario, 2018b: ONTARIO DRINKING WATER QUALITY STANDARDS. Retrieved from https://www.ontario.ca/laws/regulation/030169

Ontario, 2018c: Drinking Water Testing Services. Retrieved from https://www.ontario.ca/laws/regulation/030248

Ontario, 2018d: Procedure for Disinfection of Drinking Water in Ontario. Retrieved from https://www.ontario.ca/page/procedure-disinfection-drinking-water-ontario

Statistics Canada, G. o., 2017, November 29: Census Profile, 2016 Census: Thames Centre, Municipality [Census subdivision], Ontario and Ontario [Province]. Retrieved October 2018, from https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/details/page.cfm?Lang=E&Geo1=CSD&Code1=3539027&Geo2=PR&Code2=35&Data=Count&SearchText=Thames%20Centre&SearchType=Begins&SearchPR=01&B1=All&GeoLevel=PR&GeoCode=3539027&TABID=1


Appendix AWorkshop #2 Minutes of Meeting


Minutes The Municipality of Thames Centre – Water System Asset Inventory Workshop #2 – LoS

Ref Action Initial 01 Opening Remarks/Safety Minutes

- DO started the meeting and shared a safety minute before EW started the presentation

- Please refer to attached presentation Appendix A for presentation materials.

02 Level of Service

- Define Level of Service

- Introduce National Water and Wastewater Benchmarking Initiative (NWWBI)

03 Level of Service Activity - Define goals and sub-goals

SOPs to be sent to AECOM Repair Costs Invoices Samples to be sent to AECOM

CR

CR

04 Others Provide cost estimate of PVC pipe design

DO

Minutes

Meeting name Workshop #2 – LoS

Subject LoS

Attendees Municipality of Thames Centre: Carlos Reyes (CR), Kevin Willson (KW), Jeff Carsey (JC), Jarrod Craven (JRC), Ron Lewis (RL) AECOM: David O’Gorman (DO), Erik Wright (EW), Khalid Kaddoura (KK)

Meeting Date Febreuary 14, 2019

Time 14:30 (EST)



Prepared by KK



7/24/2019

1

David O’Gorman

Project Manager

[email protected]

Michele Samuels, M. Eng., MBA, P. Eng .

Senior Asset Management Consultant/Project Manager

[email protected]

Khalid Kaddoura

Infrastructure Asset Specialist

[email protected]

Erik Wright

GIS Specialist

[email protected], 2019

The Municipality of Thames CentreWorkshop #2 – Levels of Service

Agenda

1. Safety Minute and Project Overview

2. Understanding Levels of Service

3. Workshop Activity: Levels of Service Discussion

4. Next Steps

Page 2


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Safety Minute and ProjectOverview

With sudden changes in temperature, we are changing from Air Conditioning to Heat often thistime of the year. Heating equipment is a leading cause of home fire deaths. Half of home heatingequipment fires are reported during the months of December, January, and February. Somesimple steps can prevent most heating-related fires from happening.

• Keep anything that can burn at least threefeet away from heating equipment, like thefurnace, fireplace, wood stove, or portablespace heater.

• Have a three-foot “kid-free zone” aroundopen fires and space heaters.

• Never use your oven to heat your home.• Have a qualified professional install

stationary space heating equipment, waterheaters or central heating.

• Have heating equipment and chimneyscleaned and inspected every year by aqualified professional.

Safety Minute – Fire in House


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Project Tasks

Page 5

Kick-Off Meeting1

Asset Inventory2

Risk Analysis3

Condition Assessment4

Inspection5

Level of Service (LOS)6

Analysis of Life Cycle andReplacement Costs7

AC – CI Inspection8

Objectives


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Objectives

1. Define the Level of Service

2. Introduce NWWBI

3. Understand the Municipality existing Level of Service

4. Understand the Municipality desired Level of Service

Page 7

Understanding Levels ofService


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Ontario Regulation 588/17: AssetManagement Planning for MunicipalInfrastructure1. July 1, 2019 – All Municipalities are required to

prepare their first Strategic Asset ManagementPolicy.

2. July 1, 2021 – All Municipalities are required to havean Asset Management Plan for its entire coremunicipal infrastructure (non-core is due July 1,2023)

3. July 1, 2024 – All Asset Management Plans mustinclude Levels of Service the Municipality proposesto provide and a strategy to fund the requiredactivities. Page 9

Level of Service versus Activity Targets

“Mains are inspectedand maintained

properly”

“Provide reliabledistribution system”

“Performmaintenance

activities based ondefined periods”

“Attainment ofdistribution system

inspection andmaintenance targets”

“Our distributionsystem operates

reliably”

Page 10


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What are Levels of Service?

– Quantification of benefits that a municipal customerreceives from the Municipality’s water distribution services

– Service outcomes received from infrastructure – related toactivity targets but not the same

– Levels of Service subsequently define organizational goalsand activities, and therefore the required funding

– Levels of Service allow for trade-offs between serviceoutcomes based on willingness of the Municipality andresidents to pay

Page 11

Approach: The National Water and WastewaterBenchmarking Initiative

– Through the NWWBI,AECOM and participatingmunicipalities haveidentified a goal model forwater distribution services

– Goal model sets theframework for identifyingLoS for water networkmanagement

ProtectPublic

Health + Safety

Page 12


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Approach: The National Water and WastewaterBenchmarking Initiative (cont)– Performance measuring

can be used to defineand monitorperformance for eachgoal.

– Desired performance ismatched to industry bestpractice

Page 13

Workshop Activity: Levels ofService


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Workshop Methodology

1. Understand Municipality’s overarching water distributiongoals

2. How well are we achieving those goals?i.e. current level of service that Municipality is providing

3. What should the Municipality’s level of service be?i.e. desired or target level of service

Page 15

Goal #1 – Protect theEnvironment


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Goal #1 – Protect the Environment

Sub-goal Performance Measure

The Municipality shall have an annual goal forthe amount of water loss. The Municipality shallhave documentation defining what is included inthis calculation. The water loss goal of theMunicipality should at a minimum be consistentwith the industry standard.

Infrastructure Leakage Index / Operating Index*Non-Revenue Water in L/Connection/Day*

Existing Level of Service Desired Level of Service

Water rate has been implemented. Rate isstructured to limit consumption to 50 cubicmeters. Standards are the same for residentialand commercial users. Lekage is also monitored(percentage of what isn’t accounted for).

Remain below industry targets for water loss.

Page 17

Page 18


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Page 19

Goal #1 – Protect the Environment


The Municipality shall have a system forestimating (quantifying) leakage on an annual

basis. The system shall express leakage interms of gal/d/mi (m3/d/km) of distribution pipe.

System Length Tested for Leakage


No physical leak detection. Continue to monitor leakage.

Page 20


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Goal #2 – Provide ReliableService and Infrastructure

Goal #2 – Provide Reliable Service and Infrastructure


The Municipality shall ensure that design criteriacomplies with design standards

Do design criteria match the applicable currentstandards (ex. AWWA)?Are design criteria reviewed on a cycle?


Current design standard is from 1989. Currentlyfollowing City of London.

Adopt design standards at the municipal level.

Page 22


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Goal #2 – Provide Reliable Service and InfrastructureSub-goal Performance Measure

The Municipality shall have a prevention andresponse plan established to detect and respondto internal corrosion and deposition problems in

the distribution system.Inspection of the condition of piping for

perforations, tuberculation, and other conditionsrelated to structural integrity and hydraulic

capacity. Information to be recorded for use inpipeline condition assessment.

• Is a condition assessment plan in place tomonitor and gather data on the system?

• Are service outages planned proactively?• Are failures documented and analyzed using

Root Cause Analysis?• Number of Main Breaks Per 100 km*• Percent of Valves Cycled• Percent of Hydrants Inspected and

Winterized• Preventative and Corrective Maintenance

Hours / System Length*


Current approach is on failure. Proactivelyreplacing the oldest mains. Age-based,complaints, and on breakage. 1 year for valvecyling. Color coding maps requirements ro eachvalve. Every year for hydrants as well. Corrective

Page 23

Page 24


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Page 25

Goal #2 – Provide Reliable Service and InfrastructureSub-goal Performance Measure

The Municipality shall have contingency andresponse plan established to resolve and

complete reactive interventions with minimizeddisruptions

• Are Contingency plans defined andrehearsed for typical failures as well ascritical assets?

• Does the Municipality maintain agreementswith contractors for the standard operatingprocedures in response to unplannedoutages?

• Number of Emergency Service ConnectionRepairs / Number of Service Connections

• Do operators maintain an inventory of spareparts matched to the specifications of theassets?


SOP for main breaks, QMS for the plant.Procedures define for both common failures aswell as critical assets. Critical spare partsmaintained by the municipality. No contractswith contractors. On site supervision by

Page 26


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Goal #3 – Meet ServiceRequirements with EconomicEfficiency

Goal #3 – Meet Service Requirements w/ EconomicEfficiency


System to be designed and constructed to becapable of delivering the maximum-day demand

and fire flow for individual and public firerequirements.

Municipality to evaluate flows with tools such ashydraulic modeling, on a basis to be determinedby the utility, and corrective action plans to beimplemented when deficiencies are identified.

Do regulatory requirements achieved foroperating pressures and fire flow?


Hydraulic model almost complete. Continue tomeet current oeprating pressures.No complaintsrelated to systme pressure.

Page 28


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Goal #3 – Meet Service Requirements w/ EconomicEfficiency


The Municipality shall have a program forevaluating and upgrading existing portions of the

distribution system as required.

• Is condition assessment plan based on riskprofiles and deployment costs?

• Cost of Main Break Repairs as % of TotalO&M Cost*

• Volume of non-revenue water per connectionper day


Page 29

Page 30


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Goal #4 – Provide a Safe andProductive Workplace

Goal #4 – Provide a Safe and Productive Workplace


Personnel performing work affecting distributionsystem operation shall be competent on the

basis of appropriate education, training, skills,test requirements, and experience as required

by the governing regulatory agency. TheMunicipality should endeavor to evaluate

procedures and processes used by workers withthe intent of optimizing their operation.

• Are health and safety plans in place as partof standard operating procedures?

• Are regulatory requirements for O&Machieved (MTO Book 7 for Traffic Control,Occupational Health and Safety Act, etc.)

• Number of hours dedicated to safety trainingper year.


Tailgate meetings, confined space plans, jobtraining, annual emergency managementtraining. Rehearsals of main breaks, sampling,pump failures. Traffic control delegated tocontractors.

Continue to follow current practices. Purchasenew equipment (ex. PPE) as neeeded).

Page 32


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Goal #4 – Provide a Safe and Productive Workplace


The Municipality shall establish writtenmaintenance procedures that document all

functioning and maintenance activities requiredfor the distribution system

• Are activities defined and controlled usingSOPs?

• # of O&M Accidents with Lost Time / 1,000O&M Labour Hours*

• Overtime hours paid as a result ofemergency repairs


SOPs defined for most activities. JHSA recordsO&M accidents. Overtime mainly for breaks.

Page 33

Page 34


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Goal #5 – Satisfied andInformed Customers

Goal #5 – Satisfied and Informed Customers


The Municipality train required staff to efficientlycommunicate with customers on assets relatedissues and have some established programs toeducate customers about the assets (Informed

Customers)

• Are customer-facing staff knowledgeable ofthe assets, common issues, and customerquestions?

• Does the municipality educate the publicthrough outreach efforts?

• Does Council endorse the Levels of Serviceproposed for O.Reg 588/17 compliance?


Residents call the main office. Questionsdirected straight to Environmental Service.Complaints are tracked with forms forresolutions. Most complaints driven by internalplumbing. More discolored water calls inThorndale (source water driven). Flushing istwice per year in thorndale to prevent film

Continue to address complaints as they arise.Address groundwater issues using flushing.Developing new website with information forwater distribution. Meet expectations for highlevel of service (match current).Page 36


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Goal #5 – Satisfied and Informed Customers


Targeted Response Times, Pressure, Taste,Odour, Colour, and Staining, (Satisfied

Customers)

• # of Water Pressure Complaints byCustomers / 1,000 People Served*

• Target Response Times for Emergencies andAttainment

• Target Response Times for Non-Emergencies and Attainment


Page 37

Page 38


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Goal #6 – Protect PublicHealth and Safety

Goal #6 – Protect Public Health and Safety


The Municipality shall develop and implement asystematic flushing program that meets the

needs of the utility, taking into consideration thecondition of the system, hydraulic capacity, water

quality, and other site-specific criteria.

• Cumulative Length Cleaned as % of SystemLength *

• Cumulative Length Cleaned


Twice for both Dorchester and Thorndale (100%of the system). Dorchester is flushed for lesstime (per hydrant).

Page 40


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Page 41

Goal #6 – Protect Public Health and Safety


The Municipality shall establish a routinedistribution system sampling plan that isrepresentative of the entire distribution systemas required by the regulatory agencies.

Is a sampling program in place? What are therequirements followed for sampling? Samplinglocations?


Both plumbing and treatment. Residual chlorineand microbiological.

Meet regulatory requirements. No additionalrequirekments from the health unit.

Page 42


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Next Steps

Next Steps

– Technical Memorandum 5 – Level of Service

– Task 7 – Life Cycle Analysis and 5-Year Plan

– Provisional Item

Page 44





aecom.com



Technical Memorandum #6: Life Cycle Analysis and 5-Year Capital Plan Water Condition Assessment and Inventory Cast Iron Replacement Needs

Prepared by:


Date: November 2019

Project #: 60586191


Distribution List



Revision History

Rev # Date Revised By: Revision Description 0 March 11, 2019 KK Initial Draft 1 August 23, 2019 KK, MS Final Review and Client Submission 2 September 23, 2019 KK, MS Draft Re-submission 3 October 15, 2019 KK, MS Final Report


AECOM The Municipality of Thames Centre Technical Memorandum #6: Life Cycle Analysis and 5-Year Capital Plan


TM6-2019-10-02-Life Cycle Analysis And 5-Year Plan_V3.Docx i


















TM6-2019-10-02-Life Cycle Analysis And 5-Year Plan_V3.Docx ii

Authors

Report Prepared By:

Khalid Kaddoura, PhD, PMP, EIT, A. CSCE

Report Reviewed By:

Chris Macey, P.Eng

Report Approved By:

Michele Samuels, M.Eng., P.Eng., MBA




TM6-2019-10-02-Life Cycle Analysis And 5-Year Plan_V3.Docx iii


1. Introduction ....................................................................................... 1



2. Study Methodology ........................................................................... 3

2.1 Defining Sustainable Funding ................................................................................. 3

2.2 Methodology ............................................................................................................ 4 2.2.1 Asset Lifecycle Analysis ......................................................................................... 4 2.2.2 Cost Estimation ...................................................................................................... 4

3. Watermain Replacement Value ......................................................... 6

4. Likelihood of Failure Screening Approach ....................................... 7

4.1 Fitted Weibull Analysis Model ................................................................................. 7

5. Capital Improvement Methodology ................................................... 9

5.1 Echologics Inspection.............................................................................................. 9

5.2 Intervention Options ................................................................................................ 9 5.2.1 Corrosion Protection ............................................................................................... 9 5.2.2 Structural Lining ................................................................................................... 11 5.2.3 Intervention Options Costs ................................................................................... 11

5.3 Maintenance .......................................................................................................... 11

6. Capital Improvement Plan Results ................................................. 12

6.1 Replacement Costs ............................................................................................... 12

6.2 Maintenance Costs................................................................................................ 12

6.3 Proposed Five-Year Investment Plan .................................................................... 12


7.1 Conclusions ........................................................................................................... 14


List of Figures Figure 1: The Expenditure “Echo” to Replace Aging Infrastructure Assets ........................................................... 3 Figure 2: Financial Model Methodology ............................................................................................................... 4 Figure 3: Watermains Replacement Costs by Material and Diameter ................................................................... 6 Figure 4: City of Toronto Watermain Break Reduction Program ......................................................................... 10 Figure 5: City of Calgary Watermain Break Reduction Program ......................................................................... 10 Figure 6: Proposed 5-Year Capital Plan ............................................................................................................ 13




TM6-2019-10-02-Life Cycle Analysis And 5-Year Plan_V3.Docx iv

List of Tables Table 1: AACE International Recommended Practice No. 18R-97 for Cost Estimate Classification ..................... 5 Table 2: Watermains Replacement Costs........................................................................................................... 6 Table 3: Calculated Estimated Service Life for PVC 150 mm and 250 mm.......................................................... 8 Table 4: Echologics Inspection Results .............................................................................................................. 9 Table 5: Decision Variable Approximate Intervention Costs .............................................................................. 11 Table 6: Maintenance Strategy Unit Costs........................................................................................................ 11 Table 7: Replacement Cost Per Pipeline .......................................................................................................... 12 Table 8: Maintenance Costs During Five-year Period ....................................................................................... 12 Table 9: Proposed 5-Year Capital Plan ............................................................................................................ 13

Appendices Appendix A. PVC Pipelines Calculated ESL Appendix B. Pipelines Identified for Potential Replacement Appendix C. Pipelines Identified for Leak Detection Program




TM6-2019-10-02-Life Cycle Analysis And 5-Year Plan_V3.Docx 1

1. Introduction

1.1 Project Background The Municipality of Thames Centre (the Municipality) is charged with maintaining and renewing a diverse portfolio of mixed vintage infrastructure within the bounds of available funding levels. At the same time, the Municipality continues to be subject to public demands for high levels of municipal service, increased development and growth, and as infrastructure networks continue to age, the Municipality faces increased exposure to liability and risk. The Municipality relies on a water network system of approximately 60 km of watermain infrastructure (about 2 km of watermains are privately owned) to supply water and provide management services to a population of 7,500 residents. The geographic area of the Municipality, which is located east of London, Ontario, spans approximately 434 km2. Unlike wastewater and/or stormwater collection systems, pressurized watermains are often cost prohibitive to inspect, resulting in many municipalities possessing limited condition information, and in many cases managing watermains in a reactive fashion. Pressurized watermains are generally more critical assets with high Consequences of Failure (CoF). Traditional closed-circuit-television (CCTV) inspection approaches employed in sewers and/or storm systems are neither practical nor technically feasible to assess pressurized watermains. Limited redundancy affects the practicality of CCTV inspections and the complexity of pressurized pipe failure modes limit the efficacy of CCTV as a viable inspection technique for watermain condition assessment. Instead, a vast array of inspection tools and techniques, with varying levels of cost, resolution, and complexity, need to be employed to determine the condition of watermain infrastructure. The challenge in effective pressurized watermains management is in understanding the risks, identifying the appropriate inspection methodology and when to use it, and then prioritizing inspections to minimize risk exposure while optimizing budgetary allowances. On this basis, pressurized watermains can be managed through proactive risk management strategies such as inspection and operational adjustments, to reduce the risks of failure, and extend the service lives of assets. For this purpose, the Municipality has engaged AECOM to develop a risk-based state of good repair program to:

◼ Prioritize and assess watermains; ◼ Analyze pipe lifecycle; and ◼ Provide an annual funding forecast.

The risk-based framework and the associated deliverables, generated from this study, are intended to be adopted by the Municipality’s staff for ongoing use, analysis, and improvements beyond the completion of the study. Ultimately, the risk-based model should provide the Municipality with the procedures and tools to prioritize watermains for inspections including the means to assess existing pipe material inventory and prioritize these inspected watermains for renewal in the short-, mid-, and long-term. The primary objective of this study is to develop a maintenance renewal schedule through the implementation of a risk-based model for the Municipality of Thames Centre. The final output is attained after considering and completing several sub-tasks including, but not limited to, the following:

1. Reviewing inventory data; 2. Identifying failure modes and distress indicators; 3. Developing a Consequence of Failure (CoF) model, including prioritizing pipes for assessment;





4. Matching suitable inspection technologies, and planning a pipeline condition assessment trial for a critical watermain previously identified by the risk model;

5. Interpreting inspection findings to estimate the likelihood of failure (LoF); 6. Defining the level of service; and 7. Building a comprehensive risk-based decision matrix for pipe renewal.

1.2 Objectives for Technical Memorandum #6 Technical Memorandum No. 6 (TM#6) is designed to deliver a conceptual financial model based on a five-year plan for watermains management at the Municipality of Thames Centre (Municipality). The objective of this TM is to present the preliminary results of the funding requirements that will be required for future interventions.





2. Study Methodology

2.1 Defining Sustainable Funding In the developed world in general and North America in particular, the period following World War II saw considerable investment in infrastructure to support growing populations and the accompanying economic development. Here in Canada, the 1960s, 1970s, early 1990s and 2000s were periods of economic growth and rapid development, as evidenced by a large amount of infrastructure added to municipal inventories over those periods. However, no infrastructure lasts forever, and these cities are starting to see the increasing need to reinvest in their infrastructure to avoid loss of service and even catastrophic failure. In fact, it is precisely the large inventories of infrastructure built since the 1950s that are now starting to require replacement, as shown in Figure 1.

Figure 1: The Expenditure “Echo” to Replace Aging Infrastructure Assets Figure 1 might be an over-simplification of a very complex matter, but it serves to reveal a few key points:

i. All infrastructure assets have a finite life;

ii. Different types of infrastructure have different life expectancies/expected service lives (ESLs). For example, watermains, in general, are expected to last for 85 years (more or less) depending on the environmental exposures and pipeline material;

iii. Depending on the installation date, infrastructure assets will require replacement sometime in the future predicated by its expected service life. From there, the “expenditure echo” shown in Figure 1;

iv. The particular “mix” of infrastructure assets in need of replacement in any given year will depend on the installation date and ESL of the respective assets;

v. A sustainable funding level could, in theory, be determined through a detailed review of infrastructure inventory, replacement value, condition, expected service life and investment profiling.

Sustainable infrastructure funding is the funding required

to sustain assets in such a manner that meets present infrastructure needs without compromising the ability of

future generations to meet their infrastructure needs





As such, sustainable infrastructure funding is defined as the level of funding required to sustain assets in such a manner that meet present infrastructure needs without compromising the ability of future generations to meet their infrastructure needs. The following section summarises the methodology applied to determine the sustainable funding level of the Municipality’s watermain assets.

2.2 Methodology

2.2.1 Asset Lifecycle Analysis

AECOM performed this asset lifecycle analysis using a methodology originally developed by the National Research Council of Canada (NRC) and popularized by the National Guide to Sustainable Municipal Infrastructure (“InfraGuide”) best practice on Managing Infrastructure Assets. The methodology follows a series of logical steps for answering questions related to asset inventory, replacement value, condition and expected service life to develop a long-term capital replacement profile, as summarised in Figure 2.

Figure 2: Financial Model Methodology Detailed information about the Municipality’s watermain inventory can be found in TM#1 – Inventory Review and System Characteristics.

2.2.2 Cost Estimation

The costs considered in this assignment are prepared in the form of “Estimate Class” as per the Association for the Advancement of Cost Engineering (AACE) International Recommended Practice No 18R-97 for Cost Estimate Classification (Table 1). Based on this standard, the cost estimates developed for this task of the project shall be classified between 4 and 5, having an expected accuracy of +/- 50%, and suitable for conceptual cost screening.

Asset Inventory

Asset Replacement

Value

Asset Service Life

Asset Condition

Asset Investment

ProfileSUSTAINABILITY

FUNDING

• What do we have?• What is a logical breakdown of components?• Where & how do we store the data?

• What is it worth?• How much do the respective components cost?• Is the value in 2011 dollars?

• How long is the asset expected to be of service?• Can the components be grouped into homogeneous groups based on expected service life?• What are other municipalities using for service lives?

• What is the asset condition?• What condition data is available?• When was the asset installed?

• When does it need to be replaced?• How much will it cost?• How much need to be invested on average and what is the current shortfall?

• What is it worth? • How much do the respective components cost? • Is the value in 2019 dollars?





Table 1: AACE International Recommended Practice No. 18R-97 for Cost Estimate Classification





3. Watermain Replacement Value

Table 2 and Figure 3 show replacement costs for all linear assets owned and operated by the Municipality. In general, the most recommended material type to replace existing distribution watermains up to 375 mm is PVC. These pipelines should be designed according to AWWA C900 standard. Based on the information gathered from the Municipality, replacing pipelines ranging from 150 mm to 300 mm would cost between $771 to $777 per metre, excluding design and miscellaneous/administrative costs. Applying factors of 10% for design and 15% for miscellaneous/administrative costs, the average unit replacement cost would be approximately $980/m. Therefore, total replacement value for all municipally-owned watermain is estimated at approximately $57 M. Approximately, 69% of replacement costs ($39 M) is dominated by Polyvinyl Chloride (PVC) material type and 25% of the total replacement cost ($47 M) is governed by 150 mm diameter size.

Table 2: Watermains Replacement Costs

Material 50 mm 100 mm 150 mm 200 mm 250 mm 300 mm Total Polyvinyl Chloride (PVC) $163,000 $123,000 $14,000,000 $12,000,000 $9,000,000 $3,000,000 $39,000,000 Ductile Iron (DI) $0 $46,000 $9,000,000 $3,000,000 $3,000,000 $70,00 $15,000,000 Copper (CU) $15,000 $0 $0 $0 $0 $0 $15,000 Cast Iron (CI) $0 $0 $732,000 $0 $0 $0 $732,000 Asbestos Cement (AC) $0 $0 $1,600,000 $0 $0 $0 $1,600,000 High Density Polyethylene (HDPE) $0 $0 $0 $0 $0 $148,000 $148,000

Polyethylene (POLY) $0 $0 $5,000 $0 $0 $0 $5,000 Total $178,000 $169,000 $25,000,000 $15,000,000 $12,000,000 $3,000,000 $57,000,000

Figure 3: Watermains Replacement Costs by Material and Diameter





4. Likelihood of Failure Screening Approach

AECOM developed a risk-based framework (refer to TM#2: Initial Criticality Findings) that considered available break history to estimate a two-parameter Weibull distribution analysis. Based on the presented methodology, the shape and scale factors were calculated for PVC 150 and 250 mm and DI 150 mm. It is noted, that based on recent GIS data supplied by the Municipality, the DI break record observed previously is actually CI. Therefore, the fitted Weibull for the DI 150 mm is no longer applicable. In TM#2: Initial Criticality Findings, three cumulative density function (CDF) curves were established using the Weibull distribution analysis (equation [1]).

𝑹(𝒕) = 𝟏 − 𝑷(𝑻 ≤ 𝒕) = 𝟏 − 𝑭(𝒕|𝜸, 𝜷) = 𝒆−(

𝒕

𝜷)

𝜸

[1] Where: R (t) = Is the reliability at any time (t) P = Is the probability of failure at any time (t) F = Is the distribution function at any time (t) given a defined shape and scale factors 𝛾 = Is the shape factor; it is a non-negative value 𝛽 = Is the scale factor; it is a non-negative value These curves incorporated some of the available failure records data supplied by the Municipality. This methodology was developed based on the direction of the Municipality to incorporate the failure data. The factors of the two-parameter Weibull distribution analysis were estimated using the rank regression for PVC (150 mm and 250 mm) and 150 mm Ductile Iron (DI) pipelines. Based on the estimated parameters, the reliability functions for these pipelines would be expressed according to the following equations:

𝑫𝒖𝒄𝒕𝒊𝒍𝒆 𝑰𝒓𝒐𝒏𝟏𝟓𝟎 𝒎𝒎 𝑹(𝒕) = 𝒆−(

𝒕

𝟓𝟑.𝟕𝟖)

𝟗.𝟑𝟓

[2]

𝑷𝑽𝑪𝟏𝟓𝟎 𝒎𝒎 𝑹(𝒕) = 𝒆−(𝒕

41.12)

12.40

[3]

𝑷𝑽𝑪𝟐𝟓𝟎 𝒎𝒎 𝑹(𝒕) = 𝒆−(𝒕

23.69)

𝟐.𝟒𝟗

[4] Where failure data was insufficient to establish a fitted deterioration curve, a scale factor that is equivalent to the ESL of each pipeline material was considered along with an assumed shape factor of six (refer to TM#2: Initial Criticality Findings). Therefore, the generic reliability equation for such a case is as follows:

𝑶𝒕𝒉𝒆𝒓 𝑷𝒊𝒑𝒆𝒍𝒊𝒏𝒆 𝑹(𝒕) = 𝒆−(

𝒕

𝑬𝑺𝑳)

𝟔

[5]

4.1 Fitted Weibull Analysis Model The early age breaks resulted in steep deterioration slopes when using the rank regression model. The resulting distribution produced a meantime to failure (MTTF) that was significantly low for PVC. To avoid generalizing the same deterioration rates of PVC 150 and 250 mm in the Dorchester area, the deterioration rate was locally applied were failures were observed. The screening approach provided an estimated service life of 41 years for PVC 150 mm and 24 years for PVC 250 mm. The estimated service life calculations were specifically applied to the following watermains (refer to Table 3) and are presented in Appendix A.





Table 3: Calculated Estimated Service Life for PVC 150 mm and 250 mm

Material Type Watermain ID Estimated Service Life PVC 150 mm DC_WM_535 41

DC_WM_495 41 DC_WM_514 41 DC_WM_509 41 DC_WM_508 41 DC_WM_519 41

PVC 250 mm DC_WM_900 24 DC_WM_1016 24 DC_WM_3298 24

Since there were a limited number of breaks for each of the material types, the estimated deterioration rate was significantly high and produced conservative service lives (the breaks occurred at early ages). According to the Municipality and based on visual observation upon each break, the most probable causes of the breaks were related to construction methods. Most of the observed failures in PVC pipelines were installed prior to 1975. A study by Moser and Kellogg1 (1994) found that ASTM Series pipe had twice the failure rate as pipe manufactured to the AWWA C900 Standard which was first released in 1975, largely attributed to an increased safety factor (i.e., 2.5 versus 2.0) and more robust quality assurance standards for production. Most PVC failures reported in the study were driven by defects produced by installation and were not deterioration related. PVC pipelines are flexible material and are designed to transmit the load on the pipe to the soil at the sides of the pipe. Due to their flexibility and applied loads, over time the vertical diameter gets smaller and the increase of the horizontal diameter is resisted by the soil at the sides of the pipe. Therefore, the side support (soil) may be strong enough to avoid any excessive deflection of the pipe and therefore avoiding any failure. This can be accomplished by proper installation and construction of the pipe. The soil to pipe contact is supposed to be firm. Such construction defaults along with the vulnerability of some of the PVC cohorts installed prior to 1975 will have a higher probability to fail than properly installed PVC pipelines.

1 Moser, A. P. & Kellogg, K., “Evaluation of Polyvinyl Chloride (PVC) Pipe Performance,” AWWA Research Foundation, Project #708,

Order #90644, February 1994.





5. Capital Improvement Methodology

5.1 Echologics Inspection The screening approach in estimating the likelihood of failure (LoF) can be used as a proxy to calculate condition and understand the overall state of the infrastructure. However, field inspection tools are expected to be more accurate than age-based desktop models that incorporate very few failure data. In this program a pilot inspection was conducted on multiple pipelines in the Dorchester area. The inspection relied on the ePulse acoustic tool that measures the stiffness of the pipeline inspected between two water features (e.g. hydrants). Despite the average calculated wall thickness methodology that is used by Echologics in suggesting the condition of the pipe, such an approach is still expected to be more accurate than an age-based approach. However, it is noteworthy to mention that Echologics’ average wall thickness calculations for ferrous pipelines which are attributed to localized corrosion are less accurate than pipelines characterized by the generalized corrosion. Localized corrosion occurs in ferrous pipeline installed between 1953 and 1975 and generalized corrosion occurs in ferrous pipelines installed prior to 1953. Generally, performing intervention plans are applied to medium and high CoF pipelines with medium to high likelihood of failure to ensure sustainable funding opportunities. However, the pilot inspection performed by ePulse was applied on low CoF but most of the CoF indices were closer to the medium CoF group (closer to the medium CoF breakpoint). Therefore, performing interventions on these assets are still recommended to attain certain levels of service. Echologics suggested the following results of the inspected pipelines (Table 4).

Table 4: Echologics Inspection Results

Pipe ID Pipe Material Echologics Results DC_WM_1343 CI Moderate DC_WM_1088 AC Moderate DC_WM_1085 AC Moderate DC_WM_1219 AC Moderate DC_WM_1203 DI Poor DC_WM_1171 DI Good DC_WM_1193 DI Good DC_WM_1163 AC Poor DC_WM_1167 AC Poor

5.2 Intervention Options In lifecycle assessment, intervention options can be in the form of “do nothing”, minor rehabilitation, major rehabilitation, or replacement. In ferrous pipelines, the most commonly applied rehabilitations are structural lining and corrosion protection. For all pipe replacements and as mentioned in Section 3, AWWA C900 PVC pipeline is used.

5.2.1 Corrosion Protection

Corrosion protection is one of the ferrous pipeline rehabilitation methods used to reduce the corrosion impact during service life. Such a strategy’s design life would extend to 20 years. Although the Municipality verbally stated that the soil type is noncorrosive, performing soil investigations would be significant as, in general, ferrous pipelines’ degradation is





due to corrosion mechanism that would lead to failure. By verifying the behaviour of soil, the Municipality would deduce cost-effective intervention actions compared to replacements. Programs associated with ferrous pipelines that are driven by corrosion would involve the use of a balance of corrosion mitigation and replacement. The two best documented programs of this nature are the watermain break reduction programs in Calgary, Alberta and Toronto, Ontario. Both programs have made extensive use of cathodic protection retrofits. The net result with anode retrofit programs is that their applicability is limited to locations where some residual failures are acceptable (low consequence mains), but the cost of implementation is a fraction of the cost of relining and replacement. For example, in the City of Toronto (Figure 4), cathodic protection retrofits account for approximately 80% of Toronto’s observed failure reduction and in Calgary (Figure 5) cathodic protection retrofits now accounts for over 80% of the Calgary’s preferred intervention method (by length of all breakage reduction measures applied in Calgary). The long-term potential for cost savings is such that the Municipality should trial its application early to transition its program from a replacement-based program to one that targets opportunistic locations for anode retrofit applications.

Figure 4: City of Toronto Watermain Break Reduction Program

Figure 5: City of Calgary Watermain Break Reduction Program





5.2.2 Structural Lining

Structural lining programs, as a strategy for breakage reduction in the City of Toronto, provides the Municipality with useful insight into how structural lining can accompany full segment replacements and cathodic protection retrofits to reduce breakages under the right circumstances. The cost of a structural lining provides savings when compared to an entire segment replacement but is only considered economically viable when used as a long-term rehabilitation strategy (e.g., pipes with structural liners should not also be scheduled for replacement in the short-medium term). It is assumed that the design life of the structural lining would be 50 years.

5.2.3 Intervention Options Costs

Table 5 provides estimated unit costs of watermain strategies in the Greater Toronto Area (GTA) except for the replacement option. In deciding which intervention action to consider, a benefit to cost ratio between each is commonly applied on a site by site basis. In rural areas, for example, performing replacement may be cheaper than performing trenchless technology interventions. Based on the direction of the Municipality, all interventions are based on replacements rather than utilizing minor or major rehabilitations.

Table 5: Decision Variable Approximate Intervention Costs

Decision Variable Intervention Cost Do Nothing 0 Cathodic Protection $25/m Structural Lining (AWWA M28 Class IV) $940/m Replacement – AWWA C900 PVC $980/m

5.3 Maintenance The maintenance considered in this study is related to cleaning as well as leak detection program. This study incorporates the same cleaning frequency and length followed by the Municipality. The Municipality performs cleaning in Thorndale and Dorchester areas twice a year covering the entire length. The leak detection program would give insights in case leaks are present in the network. The severity of leaks may evolve if they are not treated. Depending on the leak flow, size, and surrounding environment, leaks may lead to erosion voids, which would cause sinkholes. In this study, the leak detection program would consider the medium and high consequence of failure pipelines. Pipelines that are scheduled for interventions and are also classified as medium and high consequence will not be included in the leak detection program. The costs associated with these maintenance strategies are detailed in Table 6:

Table 6: Maintenance Strategy Unit Costs

Maintenance Strategy Unit Rate Cleaning $ 6,500/year* Leak Detection $11/m

Note: * Reported by the Municipality





6. Capital Improvement Plan Results

AECOM used inspection results from Echologics to establish a five-year capital improvement plan. Pipelines determined to be in moderate and poor condition were taken into consideration. The intervention option considered in this plan is based on replacement costs as it is the preferred option of the Municipality. The plan considers the CoF indices of the pipelines in prioritizing the inspection but also the constrained budget per year. Additionally, leak detection and cleaning costs are considered in building the five-year capital budget.

6.1 Replacement Costs Pipelines rated as moderate and poor condition, by Echologics, were taken into consideration to suggest interventions in the form of replacement. The replacement unit cost was considered as $980/m. The total replacements of pipelines would cost around $733,000. Pipelines rated as poor would cost approximately $288,000 and pipelines rated as moderate would cost roughly $445,000. Two segments of pipelines rated as poor are made of AC, while the dominant replacement cost in the poor category is made of DI. Detailed costs per pipeline are shown in Table 7.

Table 7: Replacement Cost Per Pipeline

Pipe ID Material Condition Length (m) Total Cost DC_WM_1343 CI Moderate 121 $118,000 DC_WM_1088 AC Moderate 218 $214,000 DC_WM_1085 AC Moderate 17 $16,700 DC_WM_1219 AC Moderate 98 $96,300 DC_WM_1203 DI Poor 219 $215,000 DC_WM_1163 AC Poor 55 $54,300 DC_WM_1167 AC Poor 19 $19,100

6.2 Maintenance Costs Maintenance costs considered leak detection as well as incurred cleaning costs by the Municipality. The leak detection program is designed for all medium and high CoF pipelines, whereas cleaning costs are applied to all pipelines. Table 8 shows leak detection and cleaning costs during the five-year period.

Table 8: Maintenance Costs During Five-year Period

Maintenance Total Cost (Five-year Period) Leak Detection $182,200

Cleaning $32,500

6.3 Proposed Five-Year Investment Plan The proposed five-year plan combines maintenance costs and replacement costs based on a constrained budget and consequence of failure (CoF) indices. The calculated CoF index for each pipeline was taken into consideration to prioritize the inspection and annual expenditure. In cases where a pipeline’s CoF prioritized it for replacement but was difficult to accommodate, it was postponed to the following year. Based on Figure 6, replacements would





occur in the first four years. The first and second year included pipelines rated as poor and moderate. Total replacement costs in the first two years is estimated to be approximately $150,600. In the third year, the total cost ($214,000) represented moderate condition pipelines while the fourth year’s replacement cost ($215,000) represented poor condition pipelines. Maintenance costs are divided during the five-year period by also taking into consideration the CoF results and area where the pipeline is located. Leak detection program costs in the first two years vary; in the first year, estimated costs are approximately $32,600 and roughly $29,200 in the second year. However, in the remaining three years, estimated costs were larger than $37,000. Based on these costs, the average annual reinvestment for the five-year period (AAR5) would be approximately $202,000 per year (Table 9).

Figure 6: Proposed 5-Year Capital Plan

Table 9: Proposed 5-Year Capital Plan

Item 2020 2021 2022 2023 2024 Maintenance Leak Detection $32,600 $29,100 $42,000 $41,700 $37,600

Cleaning $6,500 $6,500 $6,500 $6,500 $6,500 Intervention

(Replacement) Poor Rated $54,300 $19,100 0 $215,000 0

Moderate Rated $96,300 $134,900 $214,000 0 0 Total $222,300 $218,800 $262,500 $263,200 $44,100 AAR5 $202,000

Appendix B shows the proposed replacement year of the identified pipes. Appendix C shows the leak detection program during the next five years. It can be observed that in many instances, some pipelines that are identified in the leak detection program and are in close proximity to each other have different leak detection year. This occurred because of the CoF prioritization and due to the segregation of pipelines based on location areas (Dorchester or Thorndale), only. Therefore, Appendix C can be used to visualize the location of the pipelines identified for the leak detection program, only. The leak detection vendor is recommended to optimize the identified leak detection segments based on the actual site conditions after site visits.






7.1 Conclusions Improving infrastructure is essential to maintaining well-performing municipal assets. Whether short- or long-term planning, optimized decisions would improve overall asset condition and performance. The study considered the results of a field inspection to establish a capital improvement plan along with maintenance costs. By performing the methodology and considering the assumptions, the following is concluded:

Watermain Replacement Value:

1. The total replacement value of all watermains is approximately $57 M

2. PVC pipelines had the highest total replacement value at approximately $39 M

Five-Year Capital Plan:

1. The total replacement costs of the identified pipelines based on field inspection results were approximately $733,000

2. Most of the interventions are performed on AC pipelines with a total replacement cost of roughly $400,000

3. The estimated total replacement cost of pipelines rated as poor condition is $288,000

4. The estimated total replacement cost of pipelines rated as moderate condition is $445,000

5. The leak detection costs in the next five years are estimated to be approximately $182,000 and the cleaning costs are approximately $33,000

6. The average annual reinvestment in the five-year period is estimated to be approximately $202,000

7.2 Recommendations Based on the results of this study, AECOM recommends the following:

1. For future replacements of watermains that are 375 mm and smaller, use AWWA C900 PVC as a replacement material.

2. Conduct root-cause analysis on failed ferrous pipelines and perform soil investigations to determine the corrosivity of soil. In case soil is corrosive, corrosion protection would be a cost-effective rehabilitation option that could extend the life of the pipelines, given its applicability.

3. Perform trenchless technologies feasibility studies if the Municipality opts to use structural lining instead of replacement. Structural lining is generally limited to areas of watermains that are hydraulically adequate or will be adequate post-lining. Structural lining would be a cost-effective solution in areas where watermains scheduled for replacement do not require extensive service replacement.

4. Perform an optimized life-cycle cost analysis that would maximize the condition of the network and minimize the total lifecycle costing. The optimized-based analysis would include the Municipality’s constraints, such as annual budgets as well as timeframes, schedules, and resources. Due to the





number of pipelines involved in this assignment, such a task would require developing a programming tool using C++ or Python to solve multi-objective functions, which was outside of the scope of this assignment.

5. Review inventory and design standards used for PVC pipelines installed after 1975. The Municipality would need to confirm and update the GIS data if pipelines installed after 1975 were designed according to AWWA C900 Standard. Pipelines installed according to ASTM series would have a lower factor of safety and less quality assurance when compared to AWWA Standard that was released in 1975. It is recommended to collect pipeline information and conduct some testing to justify the need for replacing existing PVCs (failure due to constructability issues).

6. Apart from the inspection results which were used to build a five-year capital plan, one pipeline made of PVC installed in 1973 was observed in the medium CoF (DC_WM_543). Replacing this vulnerable pipeline is estimated to have an additional cost of around $359,000.

7. Conduct opportunistic sampling and physical testing on some PVC watermains. The assessment observations would give insights on whether slow crack growth due to applied stress and poor pipe extrusion quality is occurring or not. The testing would aid the Municipality to understand the limits, in which if they are exceeded, will result in future failures.

8. Perform detailed estimates to accurately determine actual replacement costs that would include watermain material supply, design, construction, and other indirect related costs.

9. The leak detection vendor should conduct site visits to appropriately plan the leak detection segment sequence.

10. Incorporate the leak detection/condition assessment results in prioritizing interventions. The five-year capital plan was based on the pilot inspection conducted on a small number of pipelines, which was not representative of the entire network. Perform interventions on the identified pipelines which are classified in high and medium consequence (refer to TM#2: Initial Criticality Findings). The identified pipelines, per the lifecycle analysis, which are in the high consequence category would be prioritized for immediate interventions followed by pipelines classified in the medium consequence of failure given enough budget in a given year.

11. Although most of the pipelines fall in the low consequence category, the Municipality should consider performing some interventions on these pipelines to avoid sudden failures. Such decisions would be related to maintaining certain levels of service, including the reduction of the number of breaks per km per year and the number of complaints. As some of these low consequence pipelines are in residential areas (i.e., Ruth St., David St., Patricia Ave, and Ross Ave.), the Municipality could still consider conducting interventions to maintain certain levels of service. According to breakage data, many of the failures occurred in this area. Sudden repetitive failures could increase the number of complaints that would impact the levels of service limits.

12. Although the low consequence pipelines were not included in the leak detection program estimates, the Municipality could perform opportunistic sampling of certain low consequence pipeline lengths as they could be contributing to non-revenue water quantity. As leakage is a driving factor for PVC pipeline failure, including some of the identified PVC that fall in the low consequence category would give insights about the causes of the failure (i.e., leaky joints and connections could lead to PVC pipe failure).


Appendix A

PVC Pipelines Calculated ESL


LegendCalculated Estimated Service Life (Years)

24

41

Others

Dorchester Area


Appendix BPipelines Identified for Potential Replacement


LegendPotential Replacement Year

2020

2021

2022

2023

Others


Watermain_ID Length (m) Diameter (mm) Material Age ESL Area Condition Replacement Cost Replacement YearDC_WM_1219 98.3 150 AC 51 86 Dorchester Moderate $96,285 2020DC_WM_1163 55.4 150 AC 46 86 Dorchester Poor $54,292 2020DC_WM_1167 19.5 150 AC 46 86 Dorchester Poor $19,106 2021DC_WM_1085 17.0 150 AC 51 86 Dorchester Moderate $16,706 2021DC_WM_1343 120.6 150 CI 64 84 Dorchester Moderate $118,201 2021DC_WM_1088 218.4 150 AC 51 86 Dorchester Moderate $213,991 2022DC_WM_1203 219.4 150 DI 46 87 Dorchester Poor $215,033 2023

2020 $150,5782021 $154,0132022 $213,9912023 $215,033

Replacement Program

Total Replacement Costs Per Year


Appendix CPipelines Identified for Leak Detection Program


LegendLeak Detection Year

2020

2021

2022

2023

2024

Others

Dorchester AreaFebruary 10, 2020 Page 311 of 320

LegendLeak Detection Year

2020

2021

2022

2023

2024

Others

Thorndale AreaFebruary 10, 2020 Page 312 of 320

Year Total Cost2020 $32,7172021 $28,2222022 $41,9842023 $41,7312024 $37,621

WATERMAINI Length Diameter Material Installation Date Age Assumed ESL Replacement Cost CoF CoF Rank Area Leak Cost YearDC_WM_1019 92.0 250 DI 1976 43 87 $89,242 73.4 HIGH Dorchester $1,012 2020DC_WM_1316 11.2 300 PVC 1997 22 87 $10,907 73.5 HIGH Dorchester $124 2020DC_WM_3206 5.6 300 PVC 1997 22 87 $5,469 73.5 HIGH Dorchester $62 2020DC_WM_1323 123.8 300 PVC 1997 22 87 $120,098 73.5 HIGH Dorchester $1,362 2020DC_WM_2613 7.4 300 PVC 1997 22 87 $7,179 73.5 HIGH Dorchester $81 2020DC_WM_987 16.4 250 PVC 1989 30 87 $15,922 73.8 HIGH Dorchester $181 2020DC_WM_986 273.5 250 PVC 1989 30 87 $265,311 73.8 HIGH Dorchester $3,009 2020DC_WM_840 182.9 250 DI 1981 38 87 $177,432 74.3 HIGH Dorchester $2,012 2020DC_WM_994 153.6 250 PVC 1989 30 87 $148,956 74.7 HIGH Dorchester $1,689 2020DC_WM_1014 443.5 250 DI 1976 43 87 $430,236 76.4 HIGH Dorchester $4,879 2020DC_WM_3901 79.6 200 PVC 2013 6 87 $77,214 77.2 HIGH Dorchester $876 2020DC_WM_988 2.4 250 PVC 1989 30 87 $2,375 77.6 HIGH Dorchester $27 2020DC_WM_989 17.3 250 PVC 1989 30 87 $16,773 77.6 HIGH Dorchester $190 2020DC_WM_915 3.1 300 PVC 2003 16 87 $3,028 78.9 HIGH Dorchester $34 2020DC_WM_931 4.2 300 PVC 2003 16 87 $4,094 78.9 HIGH Dorchester $46 2020DC_WM_917 0.7 300 PVC 2003 16 87 $631 78.9 HIGH Dorchester $7 2020DC_WM_930 0.7 300 PVC 2003 16 87 $689 78.9 HIGH Dorchester $8 2020DC_WM_821 92.1 250 PVC 1981 38 87 $89,318 80.3 HIGH Dorchester $1,013 2020DC_WM_3910 105.5 250 PVC 2013 6 87 $102,375 80.3 HIGH Dorchester $1,161 2020DC_WM_918 224.9 300 PVC 2003 16 87 $218,146 81.9 HIGH Dorchester $2,474 2020DC_WM_910 2.1 300 PVC 2003 16 87 $2,000 81.9 HIGH Dorchester $23 2020DC_WM_940 1.1 300 PVC 2003 16 87 $1,049 81.9 HIGH Dorchester $12 2020DC_WM_939 4.2 300 PVC 2003 16 87 $4,085 81.9 HIGH Dorchester $46 2020DC_WM_921 0.8 300 PVC 2003 16 87 $768 81.9 HIGH Dorchester $9 2020DC_WM_933 18.0 300 PVC 2003 16 87 $17,464 81.9 HIGH Dorchester $198 2020DC_WM_3909 118.1 250 PVC 2013 6 87 $114,546 83.3 HIGH Dorchester $1,299 2020DC_WM_832 3.5 300 HDPE 1992 27 75 $3,430 84.6 HIGH Dorchester $39 2020DC_WM_830 135.2 300 HDPE 1992 27 75 $131,110 84.6 HIGH Dorchester $1,487 2020DC_WM_929 36.3 300 PVC 2003 16 87 $35,198 84.8 HIGH Dorchester $399 2020DC_WM_944 130.6 300 PVC 2003 16 87 $126,659 86.6 HIGH Dorchester $1,436 2020DC_WM_995 242.2 250 PVC 1989 30 87 $234,929 88.9 HIGH Dorchester $2,664 2020DC_WM_999 45.5 250 PVC 1989 30 87 $44,161 91.9 HIGH Dorchester $501 2020DC_WM_998 11.1 250 PVC 1989 30 87 $10,743 91.9 HIGH Dorchester $122 2020DC_WM_997 12.6 250 PVC 1989 30 87 $12,255 91.9 HIGH Dorchester $139 2020DC_WM_996 11.9 250 PVC 1989 30 87 $11,591 91.9 HIGH Dorchester $131 2020DC_WM_992 9.6 250 PVC 1989 30 87 $9,300 91.9 HIGH Dorchester $105 2020

Leak Detection Program Summary

Leak Detection Program


WATERMAINI Length Diameter Material Installation Date Age Assumed ESL Replacement Cost CoF CoF Rank Area Leak Cost Year


DC_WM_993 12.2 250 PVC 1989 30 87 $11,870 91.9 HIGH Dorchester $135 2020DC_WM_991 9.7 250 PVC 1989 30 87 $9,434 91.9 HIGH Dorchester $107 2020DC_WM_990 8.0 250 PVC 1989 30 87 $7,714 91.9 HIGH Dorchester $87 2020DC_WM_945 18.0 300 PVC 2003 16 87 $17,484 97.0 HIGH Dorchester $198 2020DC_WM_911 25.3 300 PVC 2003 16 87 $24,579 100.0 HIGH Dorchester $279 2020DC_WM_938 24.8 300 PVC 2003 16 87 $24,009 100.0 HIGH Dorchester $272 2020DC_WM_935 24.0 300 PVC 2003 16 87 $23,254 100.0 HIGH Dorchester $264 2020DC_WM_943 22.9 300 PVC 2003 16 87 $22,247 100.0 HIGH Dorchester $252 2020DC_WM_942 14.6 300 PVC 2003 16 87 $14,120 100.0 HIGH Dorchester $160 2020DC_WM_922 12.0 300 PVC 2003 16 87 $11,639 100.0 HIGH Dorchester $132 2020DC_WM_3898 43.9 200 PVC 2013 6 87 $42,628 59.1 MEDIUM Dorchester $483 2020DC_WM_1260 117.6 250 DI 1987 32 87 $114,086 59.1 MEDIUM Dorchester $1,294 2020DC_WM_826 17.8 250 DI 1981 38 87 $17,288 59.1 MEDIUM Dorchester $196 2020DC_WM_813 139.3 250 DI 1983 36 87 $135,152 59.1 MEDIUM Dorchester $1,533 2021DC_WM_816 21.0 250 DI 1983 36 87 $20,383 59.1 MEDIUM Dorchester $231 2021DC_WM_809 121.0 250 DI 1983 36 87 $117,414 59.1 MEDIUM Dorchester $1,332 2021DC_WM_815 13.4 250 DI 1983 36 87 $12,967 59.1 MEDIUM Dorchester $147 2021DC_WM_885 105.5 250 DI 1983 36 87 $102,290 59.1 MEDIUM Dorchester $1,160 2021DC_WM_819 60.5 250 DI 1983 36 87 $58,686 59.1 MEDIUM Dorchester $666 2021DC_WM_803 24.0 250 DI 1983 36 87 $23,310 59.1 MEDIUM Dorchester $264 2021DC_WM_1285 18.9 250 DI 1987 32 87 $18,302 59.1 MEDIUM Dorchester $208 2021DC_WM_1267 116.5 250 DI 1987 32 87 $113,006 59.1 MEDIUM Dorchester $1,282 2021DC_WM_1250 11.0 250 DI 1987 32 87 $10,661 59.1 MEDIUM Dorchester $121 2021DC_WM_1273 161.2 250 DI 1987 32 87 $156,342 59.1 MEDIUM Dorchester $1,773 2021DC_WM_819 60.5 250 DI 1983 36 87 $58,686 59.1 MEDIUM Dorchester $666 2021DC_WM_814 15.3 250 DI 1983 36 87 $14,885 59.1 MEDIUM Dorchester $169 2021DC_WM_1285 18.9 250 DI 1987 32 87 $18,302 59.1 MEDIUM Dorchester $208 2021DC_WM_13 143.2 250 PVC 2001 18 87 $138,913 59.5 MEDIUM Dorchester $1,575 2021DC_WM_14 2.3 250 PVC 2001 18 87 $2,245 59.5 MEDIUM Dorchester $25 2021DC_WM_16 40.4 250 PVC 1985 34 87 $39,159 59.5 MEDIUM Dorchester $444 2021DC_WM_20 0.6 250 PVC 1985 34 87 $539 59.5 MEDIUM Dorchester $6 2021DC_WM_33 1.1 250 PVC 2001 18 87 $1,089 59.5 MEDIUM Dorchester $12 2021DC_WM_106 85.9 250 PVC 1985 34 87 $83,356 59.5 MEDIUM Dorchester $945 2021DC_WM_3301 0.4 250 PVC 2001 18 87 $396 59.5 MEDIUM Dorchester $4 2021DC_WM_108 0.4 250 PVC 1985 34 87 $348 59.5 MEDIUM Dorchester $4 2021DC_WM_1410 3.3 150 PVC 2009 10 87 $3,241 60.4 MEDIUM Dorchester $37 2021DC_WM_1428 1.7 150 PVC 2009 10 87 $1,666 60.4 MEDIUM Dorchester $19 2021DC_WM_3862 5.8 200 PVC 2010 9 87 $5,626 60.9 MEDIUM Dorchester $64 2021DC_WM_3863 114.5 200 PVC 2010 9 87 $111,023 60.9 MEDIUM Dorchester $1,259 2021DC_WM_3881 6.6 200 PVC 2010 9 87 $6,366 60.9 MEDIUM Dorchester $72 2021DC_WM_1414 60.9 150 PVC 2004 15 87 $59,120 61.3 MEDIUM Dorchester $670 2021DC_WM_1424 4.9 150 PVC 2004 15 87 $4,727 61.3 MEDIUM Dorchester $54 2021DC_WM_913 1.1 150 PVC 2003 16 87 $1,050 61.6 MEDIUM Dorchester $12 2021DC_WM_919 3.3 150 PVC 2003 16 87 $3,183 61.6 MEDIUM Dorchester $36 2021DC_WM_235 6.3 200 PVC 2004 15 87 $6,126 61.8 MEDIUM Dorchester $69 2021DC_WM_236 2.8 200 PVC 2004 15 87 $2,715 61.8 MEDIUM Dorchester $31 2021DC_WM_239 4.8 200 PVC 2004 15 87 $4,638 61.8 MEDIUM Dorchester $53 2021DC_WM_240 3.4 200 PVC 2004 15 87 $3,337 61.8 MEDIUM Dorchester $38 2021DC_WM_242 93.0 200 PVC 2004 15 87 $90,221 61.8 MEDIUM Dorchester $1,023 2021




DC_WM_241 1.5 200 PVC 2004 15 87 $1,446 61.8 MEDIUM Dorchester $16 2021DC_WM_247 1.2 200 PVC 2004 15 87 $1,212 61.8 MEDIUM Dorchester $14 2021DC_WM_1269 2.1 250 DI 1987 32 87 $2,061 62.1 MEDIUM Dorchester $23 2021DC_WM_1266 8.7 250 DI 1987 32 87 $8,486 62.1 MEDIUM Dorchester $96 2021DC_WM_1015 3.7 250 DI 1976 43 87 $3,612 62.1 MEDIUM Dorchester $41 2021DC_WM_1261 2.0 250 DI 1987 32 87 $1,900 62.1 MEDIUM Dorchester $22 2021DC_WM_1258 14.2 250 DI 1987 32 87 $13,766 62.1 MEDIUM Dorchester $156 2021DC_WM_1277 176.6 250 DI 1987 32 87 $171,323 62.1 MEDIUM Dorchester $1,943 2021DC_WM_1255 12.3 250 DI 1987 32 87 $11,912 62.1 MEDIUM Dorchester $135 2021DC_WM_1283 91.0 250 DI 1987 32 87 $88,298 62.1 MEDIUM Dorchester $1,001 2021DC_WM_1276 4.1 250 DI 1987 32 87 $3,948 62.1 MEDIUM Dorchester $45 2021DC_WM_1274 44.8 250 DI 1987 32 87 $43,479 62.1 MEDIUM Dorchester $493 2021DC_WM_707 0.4 150 DI 1986 33 87 $388 62.2 MEDIUM Dorchester $4 2021DC_WM_775 0.4 150 DI 1986 33 87 $388 62.2 MEDIUM Dorchester $4 2021DC_WM_10 15.6 250 PVC 2001 18 87 $15,089 62.5 MEDIUM Dorchester $171 2021DC_WM_342 178.5 250 PVC 2001 18 87 $173,144 62.5 MEDIUM Dorchester $1,963 2021DC_WM_306 35.9 250 PVC 2001 18 87 $34,830 62.5 MEDIUM Dorchester $395 2021DC_WM_311 16.4 250 PVC 2001 18 87 $15,931 62.5 MEDIUM Dorchester $181 2021DC_WM_342 178.5 250 PVC 2001 18 87 $173,144 62.5 MEDIUM Dorchester $1,963 2021DC_WM_1326 293.7 300 PVC 1997 22 87 $284,904 62.8 MEDIUM Dorchester $3,231 2021DC_WM_1327 10.3 300 PVC 1997 22 87 $9,943 62.8 MEDIUM Dorchester $113 2021DC_WM_1322 356.7 300 PVC 1997 22 87 $346,047 62.8 MEDIUM Dorchester $3,924 2022DC_WM_1411 9.0 150 PVC 2001 18 87 $8,766 63.3 MEDIUM Dorchester $99 2022DC_WM_1412 3.8 150 PVC 2013 6 87 $3,710 63.3 MEDIUM Dorchester $42 2022DC_WM_1427 3.8 150 PVC 2013 6 87 $3,710 63.3 MEDIUM Dorchester $42 2022

DC_WM_1431 DC_WM_1431 2.0 150 PVC 2001 18 87 $1,982 63.3 MEDIUM Dorchester $22 2022DC_WM_789 1.5 250 DI 1983 36 87 $1,486 63.6 MEDIUM Dorchester $17 2022DC_WM_787 124.2 250 DI 1983 36 87 $120,464 63.6 MEDIUM Dorchester $1,366 2022DC_WM_788 15.9 250 DI 1983 36 87 $15,450 63.6 MEDIUM Dorchester $175 2022DC_WM_1282 76.9 250 DI 1987 32 87 $74,597 63.9 MEDIUM Dorchester $846 2022DC_WM_1415 2.1 150 PVC 2004 15 87 $2,035 63.9 MEDIUM Dorchester $23 2022DC_WM_1434 2.1 150 PVC 2004 15 87 $2,035 63.9 MEDIUM Dorchester $23 2022DC_WM_859 137.7 250 PVC 1996 23 87 $133,541 64.0 MEDIUM Dorchester $1,514 2022DC_WM_985 205.9 250 PVC 1989 30 87 $199,730 64.8 MEDIUM Dorchester $2,265 2022DC_WM_831 7.7 250 PVC 1992 27 87 $7,428 65.1 MEDIUM Dorchester $84 2022DC_WM_827 66.2 250 PVC 1992 27 87 $64,180 65.1 MEDIUM Dorchester $728 2022DC_WM_2515 100.3 250 PVC 1987 32 87 $97,255 65.1 MEDIUM Dorchester $1,103 2022DC_WM_822 46.0 250 PVC 1981 38 87 $44,639 65.1 MEDIUM Dorchester $506 2022DC_WM_828 9.9 250 PVC 1992 27 87 $9,629 65.1 MEDIUM Dorchester $109 2022DC_WM_3902 2.5 250 PVC 2013 6 87 $2,417 65.1 MEDIUM Dorchester $27 2022DC_WM_3912 1.5 250 PVC 2013 6 87 $1,452 65.1 MEDIUM Dorchester $16 2022DC_WM_1319 16.4 300 PVC 1997 22 87 $15,895 65.2 MEDIUM Dorchester $180 2022DC_WM_314 118.4 250 PVC 2001 18 87 $114,881 65.4 MEDIUM Dorchester $1,303 2022DC_WM_332 86.7 250 PVC 2001 18 87 $84,134 65.4 MEDIUM Dorchester $954 2022DC_WM_341 40.4 250 PVC 2001 18 87 $39,146 65.4 MEDIUM Dorchester $444 2022DC_WM_2500 8.6 250 PVC 2009 10 87 $8,337 65.4 MEDIUM Dorchester $95 2022DC_WM_694 12.9 250 PVC 1997 22 87 $12,508 65.4 MEDIUM Dorchester $142 2022DC_WM_1016 5.7 250 PVC 1997 22 87 $5,513 65.4 MEDIUM Dorchester $63 2022DC_WM_339 19.2 250 PVC 2001 18 87 $18,629 65.4 MEDIUM Dorchester $211 2022




DC_WM_2338 17.4 250 PVC 2009 10 87 $16,857 65.4 MEDIUM Dorchester $191 2022DC_WM_823 2.2 250 DI 1981 38 87 $2,088 66.6 MEDIUM Dorchester $24 2022DC_WM_824 1.6 250 DI 1981 38 87 $1,550 66.6 MEDIUM Dorchester $18 2022DC_WM_3906 19.5 200 PVC 2013 6 87 $18,904 66.8 MEDIUM Dorchester $214 2022DC_WM_837 20.7 250 PVC 1992 27 87 $20,085 66.9 MEDIUM Dorchester $228 2022DC_WM_1295 70.9 300 DI 1976 43 87 $68,779 67.2 MEDIUM Dorchester $780 2022DC_WM_1423 112.3 200 PVC 2004 15 87 $108,933 67.4 MEDIUM Dorchester $1,235 2022DC_WM_1020 1.5 250 DI 1976 43 87 $1,447 67.4 MEDIUM Dorchester $16 2022DC_WM_737 163.9 200 DI 1986 33 87 $159,004 68.2 MEDIUM Dorchester $1,803 2022DC_WM_979 18.7 200 DI 1986 33 87 $18,121 68.2 MEDIUM Dorchester $205 2022DC_WM_980 21.3 200 DI 1986 33 87 $20,652 68.2 MEDIUM Dorchester $234 2022DC_WM_1317 8.3 300 PVC 1997 22 87 $8,059 70.6 MEDIUM Dorchester $91 2022DC_WM_1000 3.1 250 PVC 1989 30 87 $2,973 70.8 MEDIUM Dorchester $34 2022DC_WM_543 366.5 200 PVC 1973 46 87 $355,541 71.6 MEDIUM Dorchester $4,032 2022DC_WM_907 223.4 250 PVC 1989 30 87 $216,659 71.7 MEDIUM Dorchester $2,457 2022DC_WM_833 12.2 300 HDPE 1992 27 75 $11,823 72.1 MEDIUM Dorchester $134 2022DC_WM_1249 85.5 250 PVC 1987 32 87 $82,953 72.9 MEDIUM Dorchester $941 2022DC_WM_3218 23.7 250 PVC 1987 32 87 $23,016 72.9 MEDIUM Dorchester $261 2022DC_WM_3298 19.1 250 PVC 1987 32 87 $18,561 72.9 MEDIUM Dorchester $210 2022DC_WM_3911 113.7 250 PVC 2013 6 87 $110,247 72.9 MEDIUM Dorchester $1,250 2022DC_WM_3908 1.2 250 PVC 2013 6 87 $1,172 72.9 MEDIUM Dorchester $13 2022DC_WM_912 13.0 300 PVC 2003 16 87 $12,607 72.9 MEDIUM Dorchester $143 2022DC_WM_916 9.3 300 PVC 2003 16 87 $8,979 72.9 MEDIUM Dorchester $102 2022DC_WM_928 5.8 300 PVC 2003 16 87 $5,628 72.9 MEDIUM Dorchester $64 2022DC_WM_909 38.6 300 PVC 2003 16 87 $37,429 72.9 MEDIUM Dorchester $424 2022DC_WM_925 198.7 300 PVC 2003 16 87 $192,738 72.9 MEDIUM Dorchester $2,186 2022DC_WM_914 265.6 300 PVC 2003 16 87 $257,655 72.9 MEDIUM Dorchester $2,922 2022TD_WM_3160 3.2 200 PVC 2004 15 87 $3,079 73.4 HIGH Thorndale $35 2022TD_WM_3170 1.5 200 PVC 2004 15 87 $1,486 73.4 HIGH Thorndale $17 2022TD_WM_3174 0.6 200 PVC 2004 15 87 $549 73.4 HIGH Thorndale $6 2022TD_WM_50 75.9 250 PVC 2006 13 87 $73,603 75.9 HIGH Thorndale $835 2022TD_WM_114 128.4 250 PVC 2006 13 87 $124,591 75.9 HIGH Thorndale $1,413 2022TC_WM_9990 62.9 250 PVC 2010 9 87 $60,965 75.9 HIGH Thorndale $691 2022TD_WM_50 75.9 250 PVC 2006 13 87 $73,603 75.9 HIGH Thorndale $835 2022TD_WM_99 146.7 250 PVC 2006 13 87 $142,313 76.7 HIGH Thorndale $1,614 2022TD_WM_55 1.2 250 PVC 2006 13 87 $1,172 76.7 HIGH Thorndale $13 2023TD_WM_201 30.2 150 PVC 2010 9 87 $29,332 77.6 HIGH Thorndale $333 2023TD_WM_201 30.2 150 PVC 2010 9 87 $29,332 77.6 HIGH Thorndale $333 2023TD_WM_30 117.5 250 PVC 2006 13 87 $113,964 77.6 HIGH Thorndale $1,292 2023TD_WM_30 117.5 250 PVC 2006 13 87 $113,964 77.6 HIGH Thorndale $1,292 2023

TC_WM_9915 7.9 300 PVC 2010 9 87 $7,644 86.3 HIGH Thorndale $87 2023TC_WM_9914 9.6 300 PVC 2010 9 87 $9,357 86.3 HIGH Thorndale $106 2023TC_WM_9913 11.1 300 PVC 2010 9 87 $10,769 86.3 HIGH Thorndale $122 2023TC_WM_9912 9.5 300 PVC 2010 9 87 $9,232 86.3 HIGH Thorndale $105 2023TC_WM_9911 1.7 300 PVC 2010 9 87 $1,655 86.3 HIGH Thorndale $19 2023TC_WM_9910 1.7 300 PVC 2010 9 87 $1,617 86.3 HIGH Thorndale $18 2023TC_WM_9909 1.3 300 PVC 2010 9 87 $1,263 86.3 HIGH Thorndale $14 2023TC_WM_9908 1.4 300 PVC 2010 9 87 $1,322 86.3 HIGH Thorndale $15 2023TC_WM_9907 19.4 300 PVC 2010 9 87 $18,809 86.3 HIGH Thorndale $213 2023




TC_WM_9997 75.1 300 PVC 2010 9 87 $72,851 87.5 HIGH Thorndale $826 2023TC_WM_9939 5.4 300 PVC 2010 9 87 $5,258 87.5 HIGH Thorndale $60 2023TC_WM_9938 3.2 300 PVC 2010 9 87 $3,106 87.5 HIGH Thorndale $35 2023TC_WM_9937 24.3 300 PVC 2010 9 87 $23,573 87.5 HIGH Thorndale $267 2023TC_WM_9936 22.4 300 PVC 2010 9 87 $21,729 87.5 HIGH Thorndale $246 2023TD_WM_200 100.4 300 PVC 2010 9 87 $97,431 87.5 HIGH Thorndale $1,105 2023TC_WM_9927 92.1 300 PVC 2010 9 87 $89,297 87.5 HIGH Thorndale $1,013 2023TC_WM_9926 28.6 300 PVC 2010 9 87 $27,766 87.5 HIGH Thorndale $315 2023TC_WM_9924 3.5 300 PVC 2010 9 87 $3,395 87.5 HIGH Thorndale $38 2023TC_WM_9922 1.2 300 PVC 2010 9 87 $1,207 87.5 HIGH Thorndale $14 2023TC_WM_9932 48.3 300 PVC 2010 9 87 $46,851 87.5 HIGH Thorndale $531 2023TC_WM_9999 91.4 300 PVC 2010 9 87 $88,682 95.2 HIGH Thorndale $1,006 2023TC_WM_9994 2.1 300 PVC 2010 9 87 $2,002 95.2 HIGH Thorndale $23 2023TC_WM_9991 59.8 300 PVC 2010 9 87 $58,027 95.2 HIGH Thorndale $658 2023TC_WM_9935 1.8 300 PVC 2010 9 87 $1,776 95.2 HIGH Thorndale $20 2023TC_WM_9934 1.9 300 PVC 2010 9 87 $1,803 95.2 HIGH Thorndale $20 2023TC_WM_9933 2.2 300 PVC 2010 9 87 $2,127 95.2 HIGH Thorndale $24 2023TC_WM_9904 12.2 300 PVC 2010 9 87 $11,826 95.2 HIGH Thorndale $134 2023TD_WM_128 125.5 200 PVC 2006 13 87 $121,748 59.1 MEDIUM Thorndale $1,381 2023TD_WM_4001 86.7 250 PVC 2012 7 87 $84,130 59.2 MEDIUM Thorndale $954 2023TD_WM_4004 102.0 250 PVC 2011 8 87 $98,923 59.2 MEDIUM Thorndale $1,122 2023TD_WM_4002 144.6 250 PVC 2012 7 87 $140,217 59.2 MEDIUM Thorndale $1,590 2023TD_WM_4076 5.2 250 PVC 2012 7 87 $5,001 59.2 MEDIUM Thorndale $57 2023TD_WM_4003 5.7 250 PVC 2012 7 87 $5,574 59.2 MEDIUM Thorndale $63 2023TD_WM_223 11.6 250 PVC 2012 7 87 $11,243 59.2 MEDIUM Thorndale $127 2023TD_WM_225 42.3 250 PVC 2012 7 87 $40,985 59.2 MEDIUM Thorndale $465 2023TD_WM_4075 7.9 250 PVC 2012 7 87 $7,649 59.2 MEDIUM Thorndale $87 2023TD_WM_245 153.7 250 PVC 2011 8 87 $149,060 59.2 MEDIUM Thorndale $1,690 2023TD_WM_183 119.5 200 PVC 2006 13 87 $115,896 59.4 MEDIUM Thorndale $1,314 2023TD_WM_3097 3.6 150 PVC 1987 32 87 $3,529 59.5 MEDIUM Thorndale $40 2023TD_WM_3071 0.8 150 PVC 1977 42 87 $773 59.5 MEDIUM Thorndale $9 2023TD_WM_3072 3.0 150 PVC 1977 42 87 $2,948 59.5 MEDIUM Thorndale $33 2023TD_WM_3095 3.6 150 PVC 1987 32 87 $3,529 59.5 MEDIUM Thorndale $40 2023TD_WM_3009 1.4 150 PVC 1995 24 87 $1,335 59.5 MEDIUM Thorndale $15 2023TD_WM_218 102.7 250 PVC 2006 13 87 $99,588 59.5 MEDIUM Thorndale $1,129 2023TC_WM_9993 2.8 150 PVC 2010 9 87 $2,670 60.4 MEDIUM Thorndale $30 2023TC_WM_9890 0.6 150 PVC 2010 9 87 $538 60.4 MEDIUM Thorndale $6 2023TD_WM_4018 2.1 150 PVC 2012 7 87 $2,058 60.4 MEDIUM Thorndale $23 2023TD_WM_4047 2.1 150 PVC 2012 7 87 $2,058 60.4 MEDIUM Thorndale $23 2023TC_WM_9949 1.2 200 PVC 2010 9 87 $1,134 60.9 MEDIUM Thorndale $13 2023TC_WM_9946 19.6 200 PVC 2010 9 87 $18,979 60.9 MEDIUM Thorndale $215 2023TC_WM_9894 2.1 200 PVC 2010 9 87 $2,064 60.9 MEDIUM Thorndale $23 2023TC_WM_9862 83.1 200 PVC 2015 4 87 $80,635 60.9 MEDIUM Thorndale $914 2023TD_WM_4028 101.4 200 PVC 2016 3 87 $98,402 60.9 MEDIUM Thorndale $1,116 2023TD_WM_269 62.3 200 PVC 2016 3 87 $60,476 60.9 MEDIUM Thorndale $686 2023TD_WM_4044 0.5 200 PVC 2016 3 87 $500 60.9 MEDIUM Thorndale $6 2023TD_WM_4045 94.2 200 PVC 2016 3 87 $91,414 60.9 MEDIUM Thorndale $1,037 2023TD_WM_21 14.6 250 PVC 2006 13 87 $14,114 62.5 MEDIUM Thorndale $160 2023TD_WM_32 0.9 250 PVC 2006 13 87 $899 62.5 MEDIUM Thorndale $10 2023




TD_WM_3100 1.3 200 PVC 2006 13 87 $1,213 62.9 MEDIUM Thorndale $14 2023TD_WM_75 1.3 200 PVC 2006 13 87 $1,213 62.9 MEDIUM Thorndale $14 2023

TD_WM_3101 2.2 200 PVC 1987 32 87 $2,147 62.9 MEDIUM Thorndale $24 2023TD_WM_3083 8.2 200 PVC 1987 32 87 $7,955 62.9 MEDIUM Thorndale $90 2023TD_WM_3090 17.3 200 PVC 1987 32 87 $16,767 62.9 MEDIUM Thorndale $190 2023TD_WM_3092 121.0 200 PVC 1987 32 87 $117,357 62.9 MEDIUM Thorndale $1,331 2023TD_WM_3094 126.4 200 PVC 1987 32 87 $122,654 62.9 MEDIUM Thorndale $1,391 2023TD_WM_3080 64.7 200 PVC 1987 32 87 $62,777 62.9 MEDIUM Thorndale $712 2023TD_WM_3085 2.1 200 PVC 1987 32 87 $2,020 62.9 MEDIUM Thorndale $23 2023TD_WM_3010 2.9 200 PVC 1995 24 87 $2,852 62.9 MEDIUM Thorndale $32 2023TD_WM_3046 1.3 200 PVC 1995 24 87 $1,213 62.9 MEDIUM Thorndale $14 2023TD_WM_3090 17.3 200 PVC 1987 32 87 $16,767 62.9 MEDIUM Thorndale $190 2023TD_WM_3080 64.7 200 PVC 1987 32 87 $62,777 62.9 MEDIUM Thorndale $712 2023TD_WM_3080 64.7 200 PVC 1987 32 87 $62,777 62.9 MEDIUM Thorndale $712 2023TD_WM_270 0.1 200 PVC 2006 13 87 $59 62.9 MEDIUM Thorndale $1 2023TD_WM_148 3.4 150 PVC 2006 13 87 $3,274 63.3 MEDIUM Thorndale $37 2023TD_WM_72 0.7 150 PVC 2006 13 87 $675 63.3 MEDIUM Thorndale $8 2023

TC_WM_9987 4.2 150 PVC 2010 9 87 $4,095 63.3 MEDIUM Thorndale $46 2023TC_WM_9954 3.0 150 PVC 2010 9 87 $2,956 63.3 MEDIUM Thorndale $34 2023TC_WM_9953 2.7 150 PVC 2010 9 87 $2,645 63.3 MEDIUM Thorndale $30 2023TC_WM_9892 1.8 150 PVC 2010 9 87 $1,712 63.3 MEDIUM Thorndale $19 2023TC_WM_9861 195.8 150 PVC 2010 9 87 $189,970 63.7 MEDIUM Thorndale $2,154 2023TC_WM_9861 195.8 150 PVC 2010 9 87 $189,970 63.7 MEDIUM Thorndale $2,154 2023TC_WM_9887 647.3 200 PVC 2010 9 87 $627,871 63.8 MEDIUM Thorndale $7,120 2023TC_WM_9869 50.0 200 PVC 2010 9 87 $48,526 63.8 MEDIUM Thorndale $550 2024TD_WM_224 4.4 250 PVC 2012 7 87 $4,315 64.0 MEDIUM Thorndale $49 2024TD_WM_133 2.6 150 PVC 2006 13 87 $2,570 64.2 MEDIUM Thorndale $29 2024TD_WM_49 0.7 150 PVC 2006 13 87 $669 64.2 MEDIUM Thorndale $8 2024

TD_WM_2997 91.1 150 PVC 1995 24 87 $88,369 64.6 MEDIUM Thorndale $1,002 2024TD_WM_3022 118.1 150 PVC 2003 16 87 $114,548 64.6 MEDIUM Thorndale $1,299 2024TD_WM_3004 11.3 150 PVC 1995 24 87 $11,006 64.6 MEDIUM Thorndale $125 2024TD_WM_4005 72.4 250 PVC 2011 8 87 $70,237 65.1 MEDIUM Thorndale $797 2024TD_WM_221 102.0 250 PVC 2012 7 87 $98,972 65.1 MEDIUM Thorndale $1,122 2024TD_WM_222 10.1 250 PVC 2012 7 87 $9,784 65.1 MEDIUM Thorndale $111 2024TD_WM_4077 4.4 250 PVC 2011 8 87 $4,270 65.1 MEDIUM Thorndale $48 2024TD_WM_4074 6.4 250 PVC 2012 7 87 $6,211 65.1 MEDIUM Thorndale $70 2024TD_WM_196 30.6 250 PVC 2006 13 87 $29,667 65.4 MEDIUM Thorndale $336 2024TD_WM_78 123.3 250 PVC 2006 13 87 $119,575 65.4 MEDIUM Thorndale $1,356 2024TD_WM_139 13.6 250 PVC 2006 13 87 $13,232 65.4 MEDIUM Thorndale $150 2024TD_WM_197 5.8 250 PVC 2006 13 87 $5,671 65.4 MEDIUM Thorndale $64 2024TD_WM_92 102.3 250 PVC 2006 13 87 $99,255 65.4 MEDIUM Thorndale $1,126 2024TD_WM_45 28.8 250 PVC 2006 13 87 $27,923 65.4 MEDIUM Thorndale $317 2024TD_WM_7 14.7 250 PVC 2006 13 87 $14,272 65.4 MEDIUM Thorndale $162 2024TD_WM_78 123.3 250 PVC 2006 13 87 $119,575 65.4 MEDIUM Thorndale $1,356 2024TD_WM_92 102.3 250 PVC 2006 13 87 $99,255 65.4 MEDIUM Thorndale $1,126 2024TD_WM_220 18.1 250 PVC 2006 13 87 $17,513 65.4 MEDIUM Thorndale $199 2024TD_WM_4017 3.0 200 PVC 2013 6 87 $2,938 66.2 MEDIUM Thorndale $33 2024TD_WM_249 101.1 200 PVC 2013 6 87 $98,037 66.2 MEDIUM Thorndale $1,112 2024TC_WM_9977 667.5 200 PVC 2010 9 87 $647,470 66.8 MEDIUM Thorndale $7,342 2024




TC_WM_9956 16.6 200 PVC 2010 9 87 $16,121 66.8 MEDIUM Thorndale $183 2024TC_WM_9952 234.3 200 PVC 2010 9 87 $227,223 66.8 MEDIUM Thorndale $2,577 2024TC_WM_9897 117.1 200 PVC 2010 9 87 $113,554 66.8 MEDIUM Thorndale $1,288 2024TC_WM_9977 667.5 200 PVC 2010 9 87 $647,470 66.8 MEDIUM Thorndale $7,342 2024TC_WM_9921 1.5 150 PVC 2010 9 87 $1,463 67.3 MEDIUM Thorndale $17 2024TC_WM_9920 1.2 150 PVC 2010 9 87 $1,208 67.3 MEDIUM Thorndale $14 2024TC_WM_9917 1.5 150 PVC 2010 9 87 $1,423 67.3 MEDIUM Thorndale $16 2024TC_WM_9916 1.4 150 PVC 2010 9 87 $1,344 67.3 MEDIUM Thorndale $15 2024TD_WM_215 115.5 300 PVC 2017 2 87 $112,008 67.3 MEDIUM Thorndale $1,270 2024TD_WM_209 136.9 300 PVC 2017 2 87 $132,774 67.3 MEDIUM Thorndale $1,506 2024TD_WM_214 13.7 300 PVC 2017 2 87 $13,317 67.3 MEDIUM Thorndale $151 2024TD_WM_207 4.4 300 PVC 2017 2 87 $4,223 67.3 MEDIUM Thorndale $48 2024TD_WM_208 16.9 300 PVC 2017 2 87 $16,410 67.3 MEDIUM Thorndale $186 2024TD_WM_213 54.3 300 PVC 2017 2 87 $52,654 67.3 MEDIUM Thorndale $597 2024TD_WM_210 7.2 300 PVC 2017 2 87 $7,016 67.3 MEDIUM Thorndale $80 2024TD_WM_107 29.3 200 PVC 2006 13 87 $28,458 67.7 MEDIUM Thorndale $323 2024TD_WM_146 2.2 200 PVC 2006 13 87 $2,147 67.7 MEDIUM Thorndale $24 2024TD_WM_146 2.2 200 PVC 2006 13 87 $2,147 67.7 MEDIUM Thorndale $24 2024TD_WM_146 2.2 200 PVC 2006 13 87 $2,147 67.7 MEDIUM Thorndale $24 2024TD_WM_273 9.4 150 PVC 2011 8 87 $9,124 68.5 MEDIUM Thorndale $103 2024TC_WM_9906 4.3 150 PVC 2010 9 87 $4,202 68.7 MEDIUM Thorndale $48 2024TC_WM_9905 1.7 150 PVC 2010 9 87 $1,667 68.7 MEDIUM Thorndale $19 2024TD_WM_61 16.6 200 PVC 2006 13 87 $16,088 69.8 MEDIUM Thorndale $182 2024

TC_WM_9889 29.0 200 PVC 2010 9 87 $28,130 69.8 MEDIUM Thorndale $319 2024TC_WM_9996 3.8 150 PVC 2010 9 87 $3,708 69.9 MEDIUM Thorndale $42 2024TC_WM_9995 3.7 150 PVC 2010 9 87 $3,541 69.9 MEDIUM Thorndale $40 2024TC_WM_9929 1.0 150 PVC 2010 9 87 $944 69.9 MEDIUM Thorndale $11 2024TC_WM_9918 0.8 150 PVC 2010 9 87 $821 69.9 MEDIUM Thorndale $9 2024TC_WM_9891 0.9 250 PVC 2010 9 87 $892 69.9 MEDIUM Thorndale $10 2024TD_WM_219 21.3 250 PVC 2006 13 87 $20,632 70.2 MEDIUM Thorndale $234 2024TD_WM_3005 13.2 200 PVC 1995 24 87 $12,781 70.7 MEDIUM Thorndale $145 2024TD_WM_14 0.6 200 PVC 2006 13 87 $623 70.7 MEDIUM Thorndale $7 2024

TD_WM_3003 5.8 200 PVC 1995 24 87 $5,607 70.7 MEDIUM Thorndale $64 2024TD_WM_3002 70.4 200 PVC 1995 24 87 $68,314 70.7 MEDIUM Thorndale $775 2024TD_WM_95 3.5 250 PVC 2006 13 87 $3,423 72.9 MEDIUM Thorndale $39 2024





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Documents

Technical Memorandum #1: Inventory Review and System