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Automated Unidirectional Flushing Software ProgramsProven Technology or Vaporware?
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Presented by:
David Stangel, [email protected]
Murray, Smith & Associates, Inc.
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Engineer as a Designer of the Human Body
Three engineering students were gathered together discussing the possible designers of the human body.
One said, ``It was a mechanical engineer. Just look at all the joints.''
Another said, ``No, it was an electrical engineer. The nervous systems has many thousands of electrical connections.''
The last said, ``Actually it was a civil engineer. Who else would run a toxic waste pipeline through a recreational area?”
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What is Unidirectional Flushing or UDF?
The sequential closing of system valves and
opening of hydrants to obtain adequate pipe
velocities to flush debris, dirty/discolored water
from the system
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How is it Different than Traditional Flushing Methods?
Additional planning is required Identification of flushing areas using hard copy maps Typically aided by a hydraulic model to identify valve/hydrant
sequence and simulate velocities and discharge rates
Targets velocities of 5 ft/s (min 3 ft/s) Traditional flushing doesn’t guarantee adequate
velocities Normally positive redundancy and looping works against
flushing
Traditional flushing may drop system pressure below 20 psi
Traditional flushing may involve all hydrants UDF only flushes strategically placed hydrants
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UDF Compared with Traditional Flushing
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Flushed Hydrant
Closed Valves
Flushed Hydrant
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Why Flush? (other than for obvious personal reasons)
Maintains distribution system water quality Restores disinfectant residual
Reduces disinfectant demand
Reduces bacterial growth
Dislodges biofilms
Removes sediments and deposits
Restores flows and pressures
Eliminates taste and odor problems
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Why Flush?
Other reasons for UDF Increases general system understanding for staff
– Integrates new staff
Identifies missing/broken valves/hydrants
Leverages hydraulic model/GIS investment
Uses less water than traditional techniques (up to 40%)
Corrosion control
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Keys to an Effective UDF Program
Plan, plan, plan
Quality maps with pertinent information for field crews
Operations staff input Incorporate parts of existing flushing programs where
possible
Public notification
Yearly or bi-yearly flushing schedule
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What Information is Required to Develop a UDF Plan?
Hydraulic model Requires a calibrated model
Steady state or extended period mode
Hydrant/valve GIS layers CAD information can be utilized if available Assumptions for locations can be made if layers don’t exist
Firm understanding of system operation
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UDF Software
Recent releases by software vendors suggest that developing a UDF plan using their tools is an easy next step.
Should we believe it?
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UDF Software cont.
It is relatively straightforward with completely clean data in exactly the required format.
We all know how often that is the case.
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Available Tools
MWH Soft & Bentley Systems
MWH Soft UDF - separate module
Requires InfoWater (ArcGIS) license
Bentley Includes UDF with all platforms
(stand alone, CAD, ArcGIS)
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Available Tools
Pricing dependent on number of pipes Example List Prices for 5000 pipe model
Bentley – WaterGEMS $12k + cost of AV MWH Soft - InfoWater $8k + UDF $7k + cost of AV
MWH Soft Valves and hydrant laterals do not increase pipe count
Pipes are not split
Bentley Requires a split where hydrants intersect pipes
Laterals must be entered
No split for valves
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Approaches to UDF
MWH Soft UDF focus
– Can automatically close all valves along pipe alignment
Bentley Starts with conventional flushing
Progresses to UDF
– Valves open as default
– User closes
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UDF Model Building Process
Add valves/hydrantsWas the model created from GIS?
Valves/hydrants to be operated should be provided
QA/QC
– Are hydrant and valve numbers populated and unique?
– Valves○ Does layer “register” with model?
– Hydrants○ Number of ports and size○ Elevations
– Hydrant laterals○ Length and diameter
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UDF Model Building Process
Valves & Hydrants are key for building the UDF database
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Hydrants
Pertinent attributes associated with hydrant
Requires preprocessing “Pipe” attributes not normally
associated with hydrants
– Length, roughness, diameter
Non-hydraulic information can be tracked
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Hydrants
Auto-associated to model pipes in InfoWater UDF Auto-calcs mainline
distance
Hydrants can be associated “mid-pipe”
Must be “built” into Bentley’s network Includes splits at hydrant
laterals
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Generated by InfoWater UDF
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Valves
Ensure correct valve/pipe association
Auto-associated InfoWater UDF
Bentley
Non-hydraulic information can be tracked
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Valve Registration
What we want to see
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Making our life interesting
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Registration Issues
Valve registration can be critical If the user wants to use valve ids for closing in the field
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Model Tools
Many InfoWater QA/QC and data building tools are unavailable in UDF Unique valve/hydrant identifiers
Hydrant elevation interpolation
Association of lateral attributes to hydrants
– Lateral length and diameter
Visual check for valve associations
General editing of valve/hydrant databases
Cannot fully leverage Domain Manager in UDF
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Model Tools cont.
In general the Bentley flushing tools are integrated into the modeling platform
Biggest limitation is the requirement for building hydrants and laterals into the model database
– Adds pipes to model increasing price
– Adds unneeded complexity for most modeling procedures
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UDF Model Building
Don’t underestimate the effort
Can be significant depending on input data quality Particularly if the model has not been created from GIS
When old data is put to a new use, previously unknown “issues” arise Plan for it
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UDF Analysis Criteria
Typical flushing velocity Min 3 ft/s
Target 5 ft/s
Shear stress criteria can be used in InfoWater
Min system pressure typically 20 psi
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Analysis Process
Using large format system map: Mark up flush zones
– Typically pressure zones or smaller
– Each zone associated with a “primary” source
– Each zone includes a number of flush sequences
– Work from source to system periphery
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Analysis Process
In the model: Identify initial flush pipeline(s)
Identify what hydrant(s) will be opened
Identify valves to be closed
– Take care not to isolate portions of the system from water
– Minimize valve closures○ Labor intensive for field crews
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Example InfoWater UDF Flushing Sequence
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Sequence 1Sequence 2
Sequence 3Sequence 4
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Tabular InfoWater UDF Output
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What Does the Field Crew Use?
They need to know: What system sources should be operating
What valves should be closed and when they should be reopened
– Identify valve number and/or street intersection
What hydrants should be opened
– Identify hydrant number
– Identify flow to target
– Identify how long to run hydrant
They need a series of maps clearly showing the sequences and associated information
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What is Currently Availablefor Field Maps?
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Field Maps
Bentley does not offer field map template
Utilities are turning to in house or consulted ArcGIS programming to develop field maps
Some utilities want maps in the same format as their standard field books
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So What Should You Do?
Software vendors focus on “first to release” rather than the product’s “polish” Positive
– Vendors willing to work with users to enhance products
Negative
– Enhancement turnaround time can be slow due to large number of software packages supported
What level of usability and beta testing should users expect?
– Price dependant
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Who Should Purchase these Tools?
Developing a flushing program Not like modeling tools that are used regularly
Takes an initial focused effort
No need to redo on a weekly/monthly basis
– unless growing rapidly
If utilities use Bentley then they already own it Otherwise:
– Utilities – No
– Consultants – Yes
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Additional Development
Primary areas for further development InfoWater UDF
– Model building and QA/QC
– Field map customization capability
Bentley
– Associate hydrants without permanent pipe splits
– A field map generator
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Future Enhancements
MWH Soft Committed to more than 20 enhancements
More incentive
– UDF module sold separately
Bentley Open to suggestions for enhancements
Less incentive
– Included in modeling suite
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Summary
UDF Ensures adequate flushing velocities are being achieved Can reduce the number of hydrants operated Can reduce the amount of flushed water used Can reduce the frequency of required flushing
– Does a more effective job of removing debris, biofilm and dirty water
Provides a target flow rate for flushing
– Should minimize unnecessary low pressures
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Summary cont.
AWWA and industry supports UDF plan development beyond traditional flushing
Software tools will be more valuable/usable once additional enhancements have been made
If a utility has: Invested in a hydraulic model
Accurate valve/hydrant information
they can develop a UDF plan with reasonable effort
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So Flush Away!
Special Thanks to: Sammamish Plateau Water and Sewer District
City of Redmond, Oregon
Matt Caldwell, Bentley Systems
Erick Heath, MWH Soft
Questions?
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