Drainage Improvements Tributary 8A and Frost Overflow ... · Drainage Improvements - Tributary 8A and Frost Overflow Channel Municipal Class Environmental Assessment 1.0 INTRODUCTION

Drainage Improvements Tributary 8A and Frost Overflow Channel Municipal Class Environmental Assessment

Prepared for:City of Greater Sudbury P.O. Box 5000, Station “A” 200 Brady Street, Tom Davies Square Sudbury, Ontario P3A 5P3

Prepared by: Earth Tech (Canada) Inc.1040 Lorne Street South, Unit #1 Sudbury, Ontario P3C 4R9

March 19, 2008

Project No. 104012

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Prepared for: City of Greater Sudbury P.O. Box 5000, Station “A” 200 Brady Street, Tom Davies Square Sudbury, Ontario P3A 5P3

Prepared by: Earth Tech (Canada) Inc. 1040 Lorne Street South, Unit #1 Sudbury, Ontario P3C 4R9

Proj ct No. 104012 e

March 19, 2008

City of Greater Sudbury Tributary 8A Drainage Improvements

Municipal Class Environmental Assessment

TABLE OF CONTENTS

1.0 INTRODUCTION AND BACKGROUND ..................................................................................................1

1.1. INTRODUCTION .............................................................................................................................................1 1.2. BACKGROUND...............................................................................................................................................1 1.3. OBJECTIVE ....................................................................................................................................................3

2.0 THE CLASS ENVIRONMENTAL ASSESSMENT PROCESS................................................................4

3.0 PHASE 1: PROBLEM IDENTIFICATION .............................................................................................10

3.1. PROBLEM STATEMENT................................................................................................................................10 3.2. STUDY AREA ..............................................................................................................................................11

4.0 PHASE 2: ALTERNATIVE SOLUTIONS TO THE PROBLEM..........................................................13

4.1. IDENTIFICATION AND DESCRIPTION OF THE ALTERNATIVE SOLUTIONS ......................................................13 4.1.1. Do Nothing (Alternative A) ...............................................................................................................13 4.1.2. Limit Growth (Alternative B).............................................................................................................13 4.1.3. Maximize Tributary 8A but allow Flooding beyond Capacity (Alternative C)..................................13 4.1.4. Construct a Flood Diversion Structure and Overflow Channel (Alternative D) ...............................14

4.2. DESCRIPTION OF THE EVALUATION METHODOLOGY ..................................................................................14 4.2.1. Application of the Evaluation Methodology ......................................................................................16

4.3. SUMMARY OF EVALUATION OF ALTERNATIVES..........................................................................................18 4.4. EVALUATION OF OVERFLOW CHANNEL LOCATIONS AND DIVERSION STRUCTURE.....................................20

5.0 SUMMARY OF PREFERRED ALTERNATIVE.....................................................................................24

5.1. UPGRADE OF INLET SPUR TO TRIBUTARY 10 (HANMER DRAIN) .................................................................25

6.0 RECOMMENDED MITIGATIVE MEASURES......................................................................................27

6.1. CONSTRUCTION RELATED IMPACTS............................................................................................................27 6.2. SEDIMENT CONTROL - EROSION..................................................................................................................28 6.3. STANDARD MITIGATION MEASURES...........................................................................................................29

7.0 SUMMARY OF CONSULTATION PROGRAM .....................................................................................30

7.1. NOTIFICATION OF COMPLETION..................................................................................................................31

8.0 RECOMMENDATIONS .............................................................................................................................33

Project No. 104012 Page I

City of Greater Sudbury Tributary 8A Drainage Improvements


APPENDICES

Appendix A EA Process

Appendix B Public Consultation Information

Appendix C Flow Calculations

FIGURES

Figure 1: Drainage Work Completed Since 1987......................................................................................... 2

Figure 2: Overview of the Class Environmental Assessment Process.......................................................... 6

Figure 3: Study Area................................................................................................................................... 11

Figure 4: Alternative A/B - Do Nothing / Limit Growth ............................................................................ 19

Figure 5: Alternative C - Maximize Tributary 8A but Allow Flooding Beyond Capacity ......................... 19

Figure 6: Alternative D (a) - Flood Diversion and Overflow Channel, along Frost Avenue...................... 21

Figure 7: Alternative D (b) - Flood Diversion and Overflow Channel, Divert Flows Easterly.................. 21

Figure 8: Alternative D - Flood Diversion Structure .................................................................................. 22

Figure 9: Typical Drainage Cross Section .................................................................................................. 22

Figure 10: Alternative D - Flood Diversion Structure and Diversion Channel .......................................... 23

Figure 11: Upgrade of Tributary 10 Inlet Spur ........................................................................................... 25

Figure 12: Preferred Drainage Improvement to Tributary 8A.................................................................... 26

TABLES

Table 1: Evaluation of Alternative Drainage Improvement Solutions........................................................ 17

Table 2: Typical Mitigation Measures ........................................................................................................ 27

Project No. 104012 Page II

City of Greater Sudbury Drainage Improvements - Tributary 8A and Frost Overflow Channel


1.0 INTRODUCTION AND BACKGROUND

1.1. Introduction The City of Greater Sudbury has completed a Class Environmental Assessment (Class EA) study to

investigate options and determine the most viable long-term related alternative for the drainage

improvements of Tributary 8A.

Tributary 8A is located in Hanmer, in the City of Greater Sudbury. Hanmer is part of a larger area known

better as Valley East. The area surrounding the proposed improvement is predominantly residential in

nature with some agricultural and commercial type uses. The proposed improvement, located to the east

of Frost Street in Hanmer, is part of a natural drainage course that occasionally overflows onto

neighbouring properties.

The requirement to improve the drainage of the natural water course and Tributary 8A was initiated by

concerned residents placing calls to Municipal Staff about standing water along the roadside ditches and

the natural drainage path.

The improvements to the drainage network are required to ensure that the water is safely drained away

from the existing residential neighbourhood located adjacent to the tributary. The proposed works are to

include:

• The improvements to Tributary 8A along the existing drainage course for the portion of Elmview

Drive to the rear properties located on the east side of Frost Street near the intersection of Gerard

Court and Marlene Avenue; and

• The construction of an Overflow Channel on a strip of land purchased by the City of Greater

Sudbury, and abutting the rear of properties located on the east side of Frost Street from Dominion

Drive to Tributary 8A.

1.2. Background Most portions of the tributary and its spurs have been altered, improved and/or maintained over the years

by the former Town of Valley East, now part of the City of Greater Sudbury (City), as shown in Figure 1.

At that time, Tributary 8A was classified by the municipality as a natural drainage course.

This project, the improvements to Tributary 8A, was first initiated in late November 2003 by the City’s

Roads and Drainage Engineer. The evaluation of this project was started in response to complaint by

Project No. 104012 Page 1



local residents to the Ward Councilor in regard to the ponding of water in ditches that were either crossing

or abutting residential properties.

The scope of the project at that time was to perform an analysis of the tributary, and based on the results

of that assessment to perform improvements to the tributary from its upper end at Highway 69 North

(Municipal Road 80) to the Whitson River, a distance of approximately 6 kilometers.

The current proposal for the improvements involves only a portion of the entire tributary between the new

Municipal Road 80 drainage outlet and Elmview Drive. This section consists of approximately 1700 m of

the existing drainage course. Within this drainage section, there is approximately 110 m of uncovered

drainage that crosses private land, while approximately 70 m is located in a covered easement. The

remainder of the 1700 m tributary meanders either under public roadways or over lands owned by the

City.

Figure 1: Drainage Work Completed Since 1987




Tributary 8A crosses privately and City owned land. Prior to these properties being purchased by the

Conservation Authority, historically, these parcels served as either a conveyance of storm water or as

storage within the flood plain. Development of these lands took place without any consideration for the

natural drainage of the area. As a result, a bottle neck at the rear of properties, north of Jeanne d’Arc and

west of Park was created because of the 15 foot easement. It is believed that the ponding of water and the

occurrence of flooding on neighbouring properties is a result of developing so close to the tributary.

In an effort to limit the further encroachment of residential development along the tributary, the NDCA

purchased individual residential lots from developers, (lots fronting on the east side of Park, the west side

of Frost and on the north and south side of Jeanne d’Arc). The City then obtained the land by land

transfer from the Nickel District Conservation Authority (NDCA) or from the former Municipality of

Valley East, through amalgamation.

The land acquired by the City from the former Town of Valley East was termed as being for future town

site development. Over the following years, those lands were severed for recreational use, and later for an

institutional use, now known as the City of Greater Sudbury Citizens Service Center and Library and non-

profit day care. All development occurred at the southerly end of the nearly 1000 m long property.

Other than these developments and a Canada Post kiosk at the north end, the property is vacant.

The section of Tributary 8A, subject to this Municipal Class Environmental Assessment, is located within

the 100-year event flood plain as defined by the NDCA in its drainage study entitled Whitson River

Hydrologic Analysis prepared by S.A. Kirchhefer Limited, dated June 1988.

The reliability of Tributary 8A to adequately convey storm flows requires expensive repairs to existing

culverts and drainage system. However, the City recognized there might be alternatives to the existing

drainage system of Tributary 8A that could address the City’s and community’s concerns.

1.3. Objective The objective of the drainage improvement to Tributary 8A is to lower the regulatory flood elevation by

increasing the discharge capacity of the drainage system. The intended result is to effectively reduce the

risks of potential flooding on neighbouring properties.




2.0 THE CLASS ENVIRONMENTAL ASSESSMENT PROCESS All Municipalities in Ontario, including the City of Greater Sudbury, are subject to the provisions of the

Environmental Assessment Act (EAA) and its requirements to prepare an Environmental Assessment for

most public works projects. The Ontario Municipal Engineers Association (MEA) “Municipal Class

Environmental Assessment” document (October 2000, as amended in 2007), provides municipalities with

a five-phase planning procedure approved under the EAA to plan and undertake all municipal water,

sewage, stormwater management and transportation projects that recur frequently, are usually limited in

scale and have a predictable range of environmental impacts.

The Municipal Class EA document also serves as a public statement of the decision making process

followed by cities in the planning and implementation of needed infrastructure.

Figure 2 illustrates the process followed in the planning and design of projects covered by a Class EA,

including the City of Greater Sudbury's project. This figure incorporates steps considered essential for

compliance with the requirements of the EAA that are summarized below.

Phase 1 Identify the problem (deficiency) or opportunity.

Phase 2 Identify alternative solutions to address the problem or opportunity by taking into

consideration the existing environment and establish the preferred solution accounting for

public and agency review and input.

Phase 3 Examine alternative methods of implementing the preferred solution based upon the

existing environment, public and agency input, anticipated environmental effects and

methods of minimizing negative effects and maximizing positive effects.

Phase 4 Document, in an Environmental Study Report, a summary of the rationale and the

planning, design and consultation process followed in the project and make such

documentation available for scrutiny by review agencies and the public.

Phase 5 Complete contract drawings and documents; proceed to construction and operation and

monitor construction for adherence to environmental provisions and commitments.

Where special conditions dictate, also monitor the operation of the completed facilities.




Based on the MEA Municipal Class EA (2000) document, projects are classified as either Schedule “A”,

“B” or “C” projects. Each of these classifications requires a different level of review to complete the

requirements of the Class EA, and thus comply with the EAA, as noted below:




Figure 2: Overview of the Class Environmental Assessment Process

PHASE 1Identify & Describe the Problem

or Opportunity

PHASE 1Identify & Describe the Problem

or Opportunity

Schedule ‘B’

Project

Mandatory Review Agency/Public Consultation

Mandatory Review Agency/Public

Notification

PHASE 5Complete Drawings & Documents - Proceed to Construct, Operate &

Monitor Project

PHASE 5Complete Drawings & Documents - Proceed to Construct, Operate &

Monitor Project

Mandatory Review Agency/PublicConsultation

Mandatory Review Agency/Public

Notification

Discretionary Review Agency/PublicConsultation

Schedule ‘C’

Project

Public Information CentreAugust 2005

Schedule ‘A’, ‘B’ & ‘C’ Projects

PHASE 2Evaluate Alternative Solutions

& Establish the Preferred Solution

PHASE 2Evaluate Alternative Solutions

& Establish the Preferred Solution

PHASE 3Identify Alternative Design,

Environmental Effects & Preferred Design

PHASE 3Identify Alternative Design,

Environmental Effects & Preferred Design

PHASE 4Prepare Environmental Study Report (ESR) Documenting

Phases 1-3

PHASE 4Prepare Environmental Study Report (ESR) Documenting

Phases 1-3

File Env ironmentalStudy Report

Opportunity for Part llOrder Request

(formerly referred to as ‘Bump-up’)

Schedule ‘A’Project

Project File

Prepa red fo r:City of Grea te r Su dbu ryPO Bo x 5 00 0, STN´A´, 2 00 Brad y S t. Sud bu ry, O N Ca nad a P3 A 5P3

City of Greater SudburyTributary 8A

Drainage Improvement and Overflow Channel


Dece mbe r 2 00 7

Indicates Where Project Currently is at in Class EA Process

Discretionary Review Agency/Public Consultation

Notice of Project InitiationApril 2005




Schedule “A” Projects are limited in scale, have minimal adverse effects and include the majority of

municipal water operations, sewage, stormwater management, and maintenance

activities. These projects are approved and may be implemented without following the

Class EA planning process.

Schedule “A” projects typically include normal or emergency operation maintenance

activities where the environmental effects of these activities are usually minimal. As

such, these projects are pre-approved.

Schedule “B” Projects have the potential for some adverse environmental effects. The proponent (i.e.

the City) is required to undertake a screening process involving mandatory contact with

directly affected public and relevant review agencies to ensure that they are aware of the

project and that their concerns are addressed. Schedule “B” projects require that Phases 1

and 2 of the Municipal Class EA planning process be followed. A Project File Report or

Environmental Screening Document (ESD) must be maintained and available for review

by the public. If there are no outstanding concerns raised by the public and/or review

agencies, then the proponent may proceed to project implementation. If however, the

screening process raises a concern that cannot be resolved, then the Part II Order1

procedure (formerly referred to as a “bump-up”) may be invoked. Alternatively, the

proponent may voluntarily elect to plan the project as a Schedule “C” undertaking.

Schedule “B” projects generally include improvements and expansion to existing

facilities where there is potential for some adverse environmental impacts. Examples of

Schedule “B” projects include the establishment of new water supply pumping stations

and reservoir and watermain extensions where such facilities are located outside of an

existing municipal road allowance or utility corridor, or involves water crossings. As a

result, the proponent is required to proceed through a screening process (Phases 1 and 2)

including consultation with those who may be affected.

1 Part II Order refers to a request to the Minister of the Environment for a project to comply with Part II (addresses individual Environmental Assessments) of the Environmental Assessment Act. The requirement to prepare an individual Environmental Assessment (EA) involves the preparation of a Terms of Reference and EA document that is submitted to the Ministry of the Environment (MOE), other government agencies and the public for review. This can be considered a large study undertaking that has historically been applied to large-scale significant infrastructure projects such as major highway proposals.




Schedule “C” Projects that have the potential for significant environmental effects must proceed under

the full planning and documentation procedures (Phases 1 to 4) specified in the MEA

Municipal Class EA document. Schedule “C” projects require that an Environmental

Study Report (ESR) be prepared and submitted for review by the public. If concerns are

raise that cannot be resolved, then the Part II Order procedure may be invoked.

Schedule “C” projects typically include the siting-construction of new facilities and

major expansions to existing facilities, such as water or wastewater treatment plants.

City of Greater Sudbury’s Drainage Improvements Class EA Planning Schedule

As this project involves the modification, retrofit, or improvement to a retention/detention facility

including the outfall or infiltration of a system for the purpose of stormwater quality (Schedule “B”

Activity), Phases 1 and 2 of the Municipal Class EA planning process as described above apply to this

study.

Phase 1 Identify the problem (deficiency) or opportunity.

Phase 2 Identify alternative solutions to address the problem or opportunity by taking into

consideration the existing environment and establish the preferred solution accounting for

public and agency review and input.

At the conclusion of Phase 2 a project file will be prepared to summarize the rationale

and the planning, design and consultation process followed in the project. The

documentation of the project will be made available for scrutiny by review agencies and

the public. If no objections to the project are received, the project can be implemented as

documented in the project file.

Under Part C, Municipal Water and Wastewater Projects of the Municipal Class EA, section C.1.3 is

dedicated to Stormwater Management Projects. According to the description of the various stormwater

management projects, the City’s proposed project can be categorized as involving the upgrading to an

existing stormwater management system. These upgrades can consist of modifications to existing

facilities which are intended to modify flows, volumes and/or quality control. Also, these projects can be

undertaken for the management of watercourses, in this case Tributary 8A; where the management is

intended to minimize the impacts of flooding on surrounding land uses.




Where this project is concerned, the expansion or upgrading of a stormwater management project can

involve the construction of stormwater channel improvements and/or the addition of control measures

such as weirs, to control stormwater flows.

Also taken into consideration during the preparation of this Class EA were the receiving water courses,

which include overland flows through local tributaries, ditches, channels, intermittent or continuous

streams and creeks.

The proposed project was undertaken to resolve issues of flooding on the neighbouring properties in the

area of Tributary 8A, including those areas proposed for future development. The result of this project is,

therefore, intended to potentially satisfy the following objectives:

• Alleviate local flooding problems.

• Eliminate or reduce the risk of public health or safety problems/nuisances

• Expand the capacity of the stormwater system

• Improve the system

The following sections discuss the evaluation process followed to satisfy the identified problems and the

improvements to Tributary 8A.




3.0 PHASE 1: PROBLEM IDENTIFICATION Phase 1 of this two-phase Class EA planning process requires the proponent (i.e. the City of Greater

Sudbury) of an undertaking to document factors leading to the conclusion that the improvement is needed,

and ultimately, develop a clear statement of the identified problem to be investigated.

As such, the Problem Statement is the principle starting point in the undertaking of a Class EA and

becomes the central theme and integrating element of the project. It also assists in setting the scope of the

project.

3.1. Problem Statement The problem statement for the City of Greater Sudbury’s Tributary 8A Drainage Improvement project is

defined as follows:

The existing Tributary 8A drainage area presents an unacceptable health and flood risk to the

residents living within the study area. City staff have received many complaints from residents

regarding the ponding of water within the study area; this is due to the flat grades, between 0.1 and

0.2%, and uneven inverts. As well, there is an increased risk of flooding as a result of the conditions

of the existing drainage culverts.

The infilling of a tributary flowing entirely within a flood plain is unacceptable, while ditching to

depths approaching the water table is impractical.

As a result, in recent years, more residential construction has required that owners certify their

homes as being flood proof by building at an elevation specified by the Nickel District Conservation

Authority (NDCA).

Therefore, to reduce the requirement of the property owners/builders of having to make modifications

to their premises to be certified, the City decided to undertake drainage Class EA to improve the flow

through the area.

The objective of the study is to:

1. Improve the drainage of Tributary 8A along the existing drainage course;

2. Construct an overflow channel; and

3. Relocate and improve the drainage of an inlet spur of Tributary 10 (Hanmer Drain).




In order to address the above, the City of Greater Sudbury initiated this Class EA planning process which

identifies and evaluates alternative drainage improvement solutions and accordingly addresses the above

problem statement. This Class EA Project File has been prepared to determine how the City can improve

the existing drainage within the subject area.

3.2. Study Area The following section describes the project location, land uses and natural environment features. Figure 3

shows the general area subject to this Class EA study.

Figure 3: Study Area




Location

The project study area is generally located in the community known as Hanmer (Valley East), north of the

former City of Sudbury. The area subject to the improvement is located between Municipal Road 80 (MR

80) and Dominion Drive, and east of Frost Avenue. The project is located on vacant land purchased by

the City for the proposed improvements.

Land Use

Existing land uses within the study area are predominantly mixed in nature. Land uses include

residential, commercial, recreational, institutional, agricultural and rural.

Natural Environment

The natural environmental features within the project study area comprise of a drainage network

Tributary 8A, Tributary 10 (Hanmer Drain) and their inlet spurs. These areas are predominately grass

lined. The property purchased by the City of Greater Sudbury for the location of the overflow channel,

near Dominion Drive, is partially forested land.

The general flow direction of water within the study area is towards the Whitson River, located to the

south of Dominion Drive.

There are no Environmentally Sensitive Areas (ESAs), provincially significant wetlands (PSWs) or Areas

of Natural and Scientific Interest (ANSIs) with the project study area. There are also no documented

vulnerable, threatened and endangered (VTE) species within the study area. Finally, there are no known

archeological sites within the project study area.




4.0 PHASE 2: ALTERNATIVE SOLUTIONS TO THE PROBLEM

4.1. Identification and Description of the Alternative Solutions The Municipal Class EA process recognizes that there are many ways of solving a particular problem and

requires that various alternatives be considered. The City of Greater Sudbury identified and evaluated the

following alternative solutions for consideration in this Class EA:

A. Do Nothing

B. Limit Growth

C. Maximize Tributary 8A but allow Flooding Beyond Capacity

D. Construct a Flood Diversion Structure and Overflow Channel

4.1.1. Do Nothing (Alternative A)

Within the framework of a municipal Class EA, it is normal to list “Do Nothing” as an alternative. This

alternative allows comparison of risks to the environment against the other alternatives listed.

4.1.2. Limit Growth (Alternative B)

Usually to be consistent with the alternatives normally included with a municipal Class EA ‘Limit

Growth’ is evaluated. The alternative would assume that limiting growth would address the problem with

the existing stormwater management system, and therefore assumes that the problems are related to

meeting the future demand of the system.

4.1.3. Maximize Tributary 8A but allow Flooding beyond Capacity (Alternative C)

This alternative would attempt to channel all stormwater flows through the existing drainage course and

allow for excess flows to flood beyond Tributary 8A onto neighbouring properties.

This alternative would require the deepening of the existing channel bed by approximately 0.5 m at a

constant slope of 0.2% of the profile, from Frost Avenue to Elmview Drive. The width of the tributary

would also require modification ranging from 2.0 m wide upstream to about 5.0 m wide downstream.

The banks of the tributary would then be sloped at a rate of 1V:3H.

Additional improvements to the tributary would include upgrading deficient culverts under Frost Avenue

through Elmview Drive, and replacing undersized and corrugated culverts with new box culvert type

structures.




4.1.4. Construct a Flood Diversion Structure and Overflow Channel (Alternative D)

The intent of this alternative is to maintain storm flows within Tributary 8A to acceptable flood levels

while diverting excess flow to a new drainage outlet, upstream of Tributary 8A.

To increase the discharge capacity, the existing drainage course would have to be widened and deepened,

similar to Alternative C. As well, road crossings would have to be upgraded by replacing existing

corrugated steel culverts with concrete box culverts.

Flow diversion is proposed by reducing the flow rate to Tributary 8A by means of constructing a channel,

which will follow a drainage easement from Tributary 8A south to Tributary 10.

Finally, adequate elevation at the north end of the drainage channel is required in order to allow proper

drainage and clearance of the sanitary sewer under Dominion Drive, to the south. For discussion

purposes, two (2) locations were evaluated for this alternative: location (a) parallel to Frost Avenue, and

location (b) adjacent to a Hydro Electric Power Commission corridor to the east.

4.2. Description of the Evaluation Methodology Taking the various social and natural environmental aspects of the project into consideration, the four (4)

alternative solutions were comparatively evaluated according to a qualitative, rather than a numerical or

quantitative, assessment. Numerical rankings can pose significant evaluation difficulties. While a

numerical approach may appear to provide a more scientific or precise method of comparing alternative

solutions, developing a common comparative yardstick is usually subject to debate and may result in

controversy over the results.

Subjectivity inherent in many numerical ranking systems can lead to disagreement and focus attention on

rankings and assigning points, rather than concentrating on the primary objective - the comparative

evaluation of each alternative’s strengths and weaknesses to identify the best possible solution to the

identified problem/opportunity.

Therefore, a descriptive or qualitative evaluation was undertaken based on criteria developed within the

following categories of consideration representing the broad definition of the environment described in

the EA Act:

Natural Environment Criteria Considered in the Evaluation of Options

a. Potential effects on water resources including:




i. Fisheries-aquatic habitat (e.g. stream crossings)

b. Potential effects on natural heritage features including:

i. Terrestrial environment (e.g. woodlands)

ii. Environmentally Sensitive Areas (ESAs),

iii. Areas of Natural and Scientific Interest (ANSIs)

iv. Sensitive species habitat (e.g. vulnerable/threatened/endangered or locally/regionally rare

amphibians, birds and other wildlife)

c. Potential effects on environmental management planning considerations

Social/Cultural Environment Criteria Considered in the Evaluation of Options

a. Temporary disruption during construction (i.e. dust, noise, vibration, traffic management, detours,

access to property, maintain existing services).

b. Potential effects on cultural/heritage resources (e.g. archaeological, built heritage, tourist-

recreational, agricultural & aggregate resources)

c. Compatibility with current land uses

d. Compatibility with future land uses including potential for beneficial use (parklands, sports

complex etc)

Economical/Financial Environment Criteria Considered in the Evaluation of Options

a. Estimated capital costs

b. Operating and maintenance efficiencies

Technical Criteria Considered in the Evaluation of Options

a. Constructability (i.e. location, soil conditions)

b. Efficiency of drainage system

c. Ability of alternatives to provide flexibility for unforeseen changes to drainage requirements

d. Flexibility of system to handle future development pressures




e. Ability to use existing infrastructure including proximity to existing services (hydro, municipal

water/sewers, surface drainage etc.)

f. Conflicts or impacts on existing infrastructure

g. Site accessibility from major roadways

The evaluation criteria listed in Table 1 were developed for evaluating the alternatives based on a review

of the Municipal Class EA, project area, and the problems/opportunities statement.

4.2.1. Application of the Evaluation Methodology

The evaluation criteria listed above were applied to the four (4) alternative solutions to determine the

potential effects on the environment taking mitigation measures into consideration. The results are

summarized in Table 1 and expanded upon in more detail as follows.

Project No. 104

012 Page 16



Table 1: Evaluation of Alternative Drainage Improvement Solutions

Natural Environmental

Social/Cultural

Economic/Financial

Technical Alternative Solution

Potential effects to the natural environment. (Vegetation removal, etc.)

Potential effects from construction/ visual/compatibility/ daily operation Potential human health risk Potential capital

cost Operation and

Maintenance Cost Potential structure/site

requirements Potential to reducing impact

of flooding on local properties

Ability to adequately convey stormwater

flows

Evaluation Summary

Alternative A:

Do Nothing

No man-made impacts on the natural environment.

Potential impact from continued flooding on the natural environment.

No impact from construction.

Potential for continued impacts from flooding on properties along Tributary

8A

Minimal costs associated with

general maintenance.

Minimal maintenance but

potential for higher O&M costs in the

future due to failing structures

No structure requirements

Will not reduce risk of flooding

Does not address flooding issues.

Rej

ecte

d

Alternative B:

Limit Growth No man-made impacts on the natural

environment. Potential impact from continued flooding

on the natural environment.

No impact from construction.

Potential for continued impacts from flooding on properties along Tributary

8A





future due to failing structures

No structure requirements

Will not reduce risk of flooding

Does not address flooding issues.

Rej

ecte

d

Alternative C:

Maximize Tributary 8A but Allow Flooding Beyond Capacity

Potential impact to local vegetation as the banks of the tributary will be modified to

contain improve the drainage area. Flooding of existing area could potentially

continue to impact local homeowners.

Local residents could experience some visual and noise impacts from

the construction of the improvements along Tributary 8A

between Frost Avenue and Elmview Drive.

Similar to Alternative A.

Higher cost from

improvement (concrete box

culverts)



future due to failing structures.

Requires the implementation of

concrete box culverts within the Tributary

8A.

Potential for continued flooding to local homes.

Does not address issue of flooding impact to local

homes. Rej

ecte

d

Alternative D (a):

Construct Flood Diversion Structure and Overflow Channel, divert flows east of Frost Avenue

Some tree removal is expected on the easterly side of the new channel to make

room for the improvements. Other improvements could have minimal impact

on the natural environment, similar to Alternative C.

The construction of the earth berm and overflow channel could cause

increased noise and vibration levels to those residents directly adjacent

to the proposed improvements.

The construction of the new overflow channel

could have potential risks to the safety of local

residents.

Highest cost based on

construction of earth berm and

overflow channel

improvement

Low future O&M; limited to

maintaining vegetation in

overflow channel and along

Tributary 8A.

Adequate elevation to construct the drainage channel and provide clearance of sanitary sewer at Dominion

Drive.

Overflow channel to greatly reduce the potential for

flooding on neighbouring property by diverting heavy

volumes of runoff to Tributary 10

Overflow channel will be deepened and widened to accommodate

higher volumes of stormwater.

Satisfies problem statement.

Acc

epte

d

Alternative D (b):

Construct Flood Diversion Structure and Overflow Channel, divert Flows adjacent to Hydro Corridor

Potential to impact vegetation and wildlife as flows would be diverted from tributary 8A to new area. New drainage channel would have to be created for diverted

flows.

Minimal disturbance should be experienced from improvements to be implemented east of Frost Street.

Minimal risk to human health during construction; potential to minimize the

impacts to homes adjacent to Tributary 8A




potential for higher O&M

costs in the future due to failing

structures

Not enough grade to provide drainage

clearance of sanitary sewer line at

Dominion Drive

Lesser degree of flooding risk to local property

owners as excess flows to be diverted to new channel.

Does not address issue completely

Rej

ecte

d

012 Page 17

Project No. 104



4.3. Summary of Evaluation of Alternatives Alternative Solution A, Do Nothing: In this case, “Do Nothing” is viewed as not acceptable for solving

the problem. It is not considered an appropriate long term strategy to rely on the existing drainage system

to address an ongoing problem. The drainage analysis revealed that Tributary 8A is incapable of

sustaining flows greater than a 2-year storm event. The community would be exposed to continued

unacceptable risks of flooding associated with heavy rain falls and snowmelts.

This option could also limit the future growth potential of the area due to the requirements on property

owners to implement flood proofing measures.

It is probable that without addressing the problem, one or more of the following circumstances could

result: 1) Major structure failure requiring emergency maintenance repairs; and 2) Major structure failure

resulting in possible risk to human health and property. Therefore, the long term cost to the residents in

the immediate area would be higher than implementing one or more of the upgrading alternatives.

Alternative Solution B, Limit Growth: Similar to the discussion of Alternative A, this alternative does

not address the risks of potential flooding. By not implementing drainage improvements, allowing

additional development to drain into Tributary 8A could potentially result in increased flooding within the

study area. See Figure 4 for illustration of Alternatives A and B.

Alternative Solution C, Maximize Tributary 8A but Allow Flooding Beyond Capacity: The City

recognizes the benefits of improving the flow characteristics of Tributary 8A. By replacing the existing

corrugated culverts with new concrete box culverts, the City could minimize the volume of material that

could get caught in the culvert during the spring thaw, thereby maximizing flows.

This improvement could reduce the risks of flooding on local property owners however the potential for

uncontrolled flooding would remain. This alternative does not satisfy the problem statement. This

alternative is shown in Figure 5.

Alternative Solution D, Construct a Flood Diversion Structure and Overflow Channel: This option

provides the best means of reducing the impacts of flooding to properties adjacent to Tributary 8A. By

constructing a flood diversion structure and an overflow channel, the volume of stormwater that was once

conveyed along Tributary 8A will be better controlled and the potential for future flooding to local home

owners greatly reduced. This option satisfies the objectives of the Class EA. Alternative D is considered

as the preferred option for satisfying the identified flooding issue.




Figure 4: Alternative A/B -Do Nothing / Limit Growth

Figure 5: Alternative C -Maximize Tributary 8A but Allow Flooding Beyond Capacity




4.4. Evaluation of Overflow Channel Locations and Diversion Structure Based on the anticipated results of diverting and reducing maximum stormwater flows away from

Tributary 8A, the following two (2) options were evaluated for the placement of the diversion channel:

• Option (a) considers constructing the overflow channel parallel to Frost Avenue, behind the

residential properties; and

• Option (b) considers diverting the excess flows of Tributary 8A easterly to a future drainage

channel, adjacent to a hydro corridor.

Of concern with the construction of the overflow channel is the conflict with the trunk sanitary sewer

crossing Dominion Drive. Therefore, a major requirement for the construction of the channel is that there

be adequate grade elevation at the north end of the channel to allow enough separation at the south end.

Option (a) provides the most gradient possible for the construction of the overflow channel. The weir at

the intersection of Tributary 8A and the Overflow helped because it raised the invert at the upper end and

allows clearance over the sanitary.

Option (b) does not fully address the potential flooding impacts of Tributary 8A to the local area.

Although storm flows would be diverted, adjacent to the hydro corridor, the risk of flooding remains to

other flat properties in the area. As well, because of the natural flow of the land (south to west at 0.20%

grade), diversion easterly runs out of grade before Dominion Drive where the drainage outlet would cross

the sanitary sewer.

The two alternatives are illustrated in Figures 6 and 7.




Figure 6: Alternative D (a) - Flood Diversion and Overflow Channel, along Frost Avenue

Figure 7: Alternative D (b) - Flood Diversion and Overflow Channel, Divert Flows Easterly




Diversion Structure: The original diversion structure proposed the construction of a weir to limit the

volume of storm flow to be conveyed through Tributary 8A. As indicated in the January 2006 Drainage

Improvement Report prepared by S.A. Kirchhefer, the weir structure is replaced with a berm and culvert.

The flood diversion structure would consist of a 900mm diameter culvert within an earth berm. The size

of the culvert would limit the flow of water, and any water that could not pass would be diverted to the

overflow channel.

Figure 8: Alternative D - Flood Diversion Structure

Figure 9 shows a typical drainage cross section for the proposed project, while Figure 8 shows a

conceptual flood diversion structure.

Figure 9: Typical Drainage Cross Section




Figure 10: Alternative D - Flood Diversion Structure and Diversion Channel

Proposed Flood

Diversion Structure




5.0 SUMMARY OF PREFERRED ALTERNATIVE Improving Tributary 8A to convey 100-year flood events would impact private property owners along its

length and it would require additional property which might not be favourable to homeowners backing on

to the tributary. Therefore, based on the evaluation in Section 4, the preferred alternative is to construct a

flow diversion structure and overflow channel to reduce the risks of flooding to properties along Tributary

8A and to better handle flows from the existing MR 80 drainage outlet. The following discussion

summarizes the preferred alternative to address the objective of the Class EA.

Flood Diversion Structure

This improvement will be constructed directly east of the residential properties on Frost Avenue, at the

intersection of the new overflow channel. The structure will consist of an earth berm and a 900 mm

diameter culvert to convey limited stormwater flows along Tributary 8A. The earth berm will be

constructed to an elevation higher than the regulatory flood line.

When the overflow channel is not conveying excess storm flows, the overflow channel would essentially

be a dry ditch. The proposed improvement will create a reverse grade within the new overflow channel

directly adjacent to the flood diversion structure, where the invert off Tributary 8A is 0.7 m deep.

When storm flows are greater than the 0.7 m invert of Tributary 8A, overflow will be diverted into the

channel and away from private properties along the existing tributary. It is expected that the Tributary 8A

invert will be sufficient to maintain the conveyance of a 5-year storm event, while anything larger will be

convey along the overflow channel down to Tributary 10.

Overflow Channel

This improvement would see the construction of a new overflow channel approximately 1000 m in length.

The channel will be constructed of sufficient dimension to carry the remainder of the storm flow for a

100-year event that Tributary 8A will not be able to convey. The channel would begin at the intersection

of Tributary 8A and the southerly end of the existing MR 80 drainage outlet. The realigned channel will

be located entirely within land acquired by the City.

In support of the preferred solution, a study entitled ‘Proposed Drainage Improvement - Whitson River

Watershed Tributary VIII-A’ was prepared by S.A. Kirchhefer Limited in January 2006. The study

discusses the proposed drainage improvements based on the design drawings prepared by the City of




Greater Sudbury. The study identifies the effects of the improvements on the regulatory flood elevation

within the study area. A copy of the study is attached to this report for information purposes.

5.1. Upgrade of Inlet Spur to Tributary 10 (Hanmer Drain) Most spurs in the study area were originally excavated with plows and tractors by the current or former

land owners. These spurs were excavated to improve drainage of the properties by providing excess

water with a drainage path to one of the Tributaries.

Currently there are two drainage culverts that run from the north side of Dominion drive to the south and

eventually drain into Tributary 10. The inlet spur that the City proposes to connect to currently collects

storm flow from portions of the Parkwood Subdivision and from roadway ditches along approximately

1.5km of Dominion Drive (east and west of Frost Avenue).

It is expected that upgrading the inlet spur of Tributary 10 will improve the conveyance of excess

stormwater flows away from residential, recreational and institutional properties north of Dominion

Drive, Figure 11. By improving the drainage under Dominion Drive and the inlet spurt, the City

anticipates that the chances of flooding within the study area will be greatly reduced. This alternative,

Figure 12, compliments alternative D and satisfies the objects of the Class EA.

Figure 11: Upgrade of Tributary 10 Inlet Spur




It should be noted that because flow data for this area has only been modeled, the frequency and

probability of how much flow will be diverted is unknown. The occurrences of flooding are also difficult

to predict because flooding in this area is dependent on many factors, including: soil saturation, rate of

thaw, snow accumulation, to name a few. The spreadsheet in Appendix C illustrates the results of the

Rational Method calculations used to evaluate the proposed improvements.

Figure 12: Preferred Drainage Improvement to Tributary 8A




6.0 RECOMMENDED MITIGATIVE MEASURES Section 6 presents established mitigative measures. Following the identification of potential impacts

associated with the project, typical mitigation measures are applied and the resultant net effect is

identified. Significant findings of this evaluation are presented below. Based on the evaluation of

potential effects, the drainage improvements to Tributary 8A are not expected to result in any significant

environmental impacts. However, the following mitigative measures are recommended to ensure that any

short-term disturbances are managed by the best available methods.

6.1. Construction Related Impacts Impacts related to construction of the water supply project will be short-term and minor. By

incorporating proper best management practices/construction techniques and controls, these impacts can

be minimized. Anticipated construction related impacts are summarized below along with the associated

mitigating measures. It is recommended that these mitigating measures, identified in Table 2, be

employed to reduce the potential impacts during the construction of the proposed works.

Table 2: Typical Mitigation Measures

Potential Impacts Mitigation Measures Social Considerations

Increase in noise related to construction equipment operation

• Comply with Municipal Noise control by-law. • Maintain equipment in an operating condition that prevents

unnecessary noise, including but not limited to non-defective muffler systems, properly secured components, and the lubrication of moving parts.

• Restrict idling of equipment to the minimum necessary to perform the specified work (no excessive idling).

Increase in dust, fumes, and odours related to excavation, construction equipment operation, etc.

• Ensure that no visible dust from construction operations escape beyond the right-of-way limits and/or causes any reduction in visibility on the roadway.

• The Ministry of the Environment criteria for noxious gases and particulate matter are not expected to be exceeded.

Construction related traffic/access • Maintain access to all entrances/exists within the project throughout the construction period.

• Post signage during the construction period to inform motorists, pedestrians, and cyclists of the following of construction zone limits, anticipated duration of construction, and alternative routes.




Table 2: Typical Mitigation Measures - Cont’d

Potential Impacts Mitigation Measures Terrestrial Environment

Vegetation and Loss of Cover

Removal or disturbance of significant trees and/or ground flora-landscape features

• Restrict-minimize removal of vegetation.

• All trees to be saved shall be clearly marked.

• Prune roots within excavation area using proper root pruning equipment prior to excavation as to minimize root tear of adjacent trees.

• Replace removed vegetation (no net loss) with approved native species.

Contamination of Soils Through Spills and Leaks

• This can be avoided by ensuring that fuel storage, refueling and maintenance of construction equipment are handled properly and not allowed in or adjacent to watercourses/bodies.

• Contingency plans must be prepared before projects begin for the control and clean up of a spill if one should occur.

Archaeology • If any archaeological and/or historical resources are discovered during the performance of construction work, the performance of the work in the area of the discovery is to halt. The Ministry of Culture (Archaeological Unit) will be notified for an assessment of the discovery. Work in the area of the discovery would not resume until cleared to do so by the Ministry.

6.2. Sediment Control - Erosion Areas of highly erodible soils (associated with location where there is a high potential for sediment

discharge to sensitive areas, such as watercourses) will be identified and investigated. An understanding

of the local site conditions will then be integrated with the following protection principles to develop an

erosion and sediment control plan for the project:

• Apply timing restrictions for work.

• Minimize soil exposure duration.

• Retain existing vegetation, where feasible.

• Encourage revegetation.

• Divert runoff away from exposed soil.

• Keep runoff velocities low.

• Trap sediment as close to the source as possible.




.3. Standard Mitigation Measures

effects outlined in this section will need to be mon

and beyond, if necessary, to ensure they are performing as intended. The frequency of the monitoring

program will vary depending upon the specifics of the required mitigation measure at a specific location

and will be undertaken accordingly. The following are excerpts from the construction sequencing and

staging section of the Contract Specifications document; additional contractor specifications can be

reviewed in the original document.

• The Contractor must schedule th

Contractor’s responsibility to erect and man detours pursuant to required notification of emergency

services.

The Contr

This project involves the excavation of a new drainage channel and improvements to an existin

Because of the length and dimension of the proposed channels, excavating, grading, compacting and

restoring/stabilizing final surfaces should be completed as one continuous operation.

For all portions of channel construction, the Contractor will be required to excavate t

6 As a condition of the construction contract, the mitigation measures associated with the potential negative

itored throughout the construction phase of the project

e work so that one lane of traffic is maintained at all times. If for any

reason, the Contractor will be required to cut through access of any road then it shall be the

• actor will be allowed to work from 7:00 a.m. to 7:00 p.m. with no restrictions. Extra hours

beyond the normal working day and work on weekends, must be approved by the Roads Engineer.

• g

tributary. These channels can carry substantial flows and must remain open most of the time.

• hen restore with

topsoil/sod or seed/mulch in close succession.




7.0 SUMMARY OF CONSULTATION PROGRAM

Notification

The public, living within the study area, were informed of the project by way of project notices, and

requested to either attend the upcoming meetings or submit written comment to project staff.

Approximately 225 notices were hand delivered a week before each meeting.

Notification of the project was also advertised in the location newspapers, Sudbury Star, Northern Life

Early consultation with local home owners was met with opposition to the project. Those individuals

living closest to the existing drainage outlet, near MR 80, were most vocal about their disapproval of the

proposed channel; they insisted that the channel should be relocated further away from their properties,

and beyond the land purchased by the City (53R-11763).

Included in Appendix B are the written responses received from those agencies contacted at the

commencement, and throughout, the planning process. Although many of the agencies contacted did not

respond to our request for input, they remain on the project contact list. All contacts were kept informed

throughout the progress of the projects.

Agency Consultation

Notification of the project was mailed to government agencies, as required by the Municipal Class EA,

inviting their comment on the proposed undertaking. The following government agencies were contacted:

• Ministry of the Environment (MOE)

• Ministry of Natural Resources (MNR)

• Ministry of Northern Development and Mines (MNDM)

• Ministry of Citizenship and Leisure (MCL)

• Nickel District Conservation Authority (NDCA)

• Federal Department of Fisheries and Oceans (DFO)

The City met with the NDCA, MNR and DFO to discuss the proposed project and was able to answer

questions and provide clarification on the project.




The City mailed project notifications to the First Nations identified in the general area of the City of

Greater Sudbury to determine if there were any identified heritage sites. No responses were received.

The Ministry of Aboriginal Affairs, as well as, INAC were contacted later to confirm that there were no

areas of cultural heritage being impacted by this proposed improvement. Again, no comments were

received.

Minutes from the agency meetings are included in Appendix B to this report.

Public Information Centre

The City of Greater Sudbury met with local residents over the last two week in August 2005. Residents

were consulted individually, either on the proposed project site or at their place of residence. The purpose

of the meetings was to present the study and to gain feedback to help scope the study further.

A public meeting was held on September 7, 2005. At that meeting the City committed to investigate the

possibility of acquiring additional land for the possible relocation off the channel. The relocation would

move the channel further east, or would provide additional buffering from the proposed side slope.

A second public meeting was held on October 5, 2005. This meeting was scheduled to inform the

residents in the area that the City had looked at relocating the channel to the east, however it was not

feasible. Again the residents were informed of the Municipal Class EA process, the opportunity to review

the project file and their opportunity to provide comment on the project.

Between the first and second meeting with the public, the City investigated additional land options as

requested, but were unsuccessful.

Minutes from the agency meetings are included in Appendix B to this report.

7.1. Notification of Completion Since this project is being undertaken in accordance with the requirements of Schedule B of the

Municipal Class EA planning process, the first step of implementing the project involves issuing a

‘Notice of Completion’ and filing the project file for public review. The ESD was filed for a 30 calendar

day review period.




The notice informed individuals of the project’s completion, including the preferred solution and their

rights regarding the Part II Order provisions. Appendix B contains a copy of the notice of completion

letter.




8.0 RECOMMENDATIONS Based on the results of the study process, and the public and agency consultation process, the following

recommendations are proposed for the implementation of the drainage improvements to Tributary 8A:

1. It is recommended that the City construct a flow diversion structure and overflow channel, east of

Frost Avenue, to convey all flows that cannot be contained within the improved channel of

Tributary 8A.

2. It is recommended that a pre-construction meeting be scheduled to discuss the implementation of

the drainage improvements. This will provide the community with an opportunity to review the

design drawings and provide comment on the final look of the project.

3. It is recommended that consideration be given to providing a drainage improvement area with a

more natural design that will be acceptable to the community.

4. It is recommended that the City address any outstanding concerns related to this project, or

subsequent Part II Order Requests, under separate cover.
