1. Automated Unidirectional Flushing Software Programs Proven Technology or Vaporware?
Presented by:
David Stangel, P.E.
Murray, Smith & Associates, Inc.

2. 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?”

3. 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

4. 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

5. UDF Compared with Traditional Flushing
Flushed Hydrant
Flushed Hydrant
Closed Valves

6. 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

7. 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

8. 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

9. 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

10. 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?

11. 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. 

12. Available Tools MWH Soft & Bentley Systems MWH Soft Bentley
UDF - separate module
Requires InfoWater (ArcGIS) license
Bentley
Includes UDF with all platforms (stand alone, CAD, ArcGIS)

13. 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

14. Approaches to UDF MWH Soft Bentley UDF focus
Can automatically close all valves along pipe alignment
Bentley
Starts with conventional flushing
Progresses to UDF
Valves open as default
User closes

15. UDF Model Building Process
Add valves/hydrants
Was 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

16. UDF Model Building Process
Valves & Hydrants are key for building the UDF database

17. Hydrants Pertinent attributes associated with hydrant
Requires preprocessing
“Pipe” attributes not normally associated with hydrants
Length, roughness, diameter
Non-hydraulic information can be tracked

18. Generated by InfoWater UDF
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
Generated by InfoWater UDF

19. Valves Ensure correct valve/pipe association Auto-associated
InfoWater UDF
Bentley
Non-hydraulic information can be tracked

20. Valve Registration
What we want to see
Making our life interesting

21. Registration Issues Valve registration can be critical
If the user wants to use valve ids for closing in the field

22. 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

23. 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

24. 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 

25. 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

26. 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

27. 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

28. Example InfoWater UDF Flushing Sequence

29. Tabular InfoWater UDF Output

30. 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

31. What is Currently Available for Field Maps?

32. 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

33. 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

34. 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

35. 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

36. Future Enhancements MWH Soft Bentley
Committed to more than 20 enhancements
More incentive
UDF module sold separately
Bentley
Open to suggestions for enhancements
Less incentive
Included in modeling suite

37. 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

38. 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

39. So Flush Away! Special Thanks to: Questions? ds@msa-ep.com
Sammamish Plateau Water and Sewer District
City of Redmond, Oregon
Matt Caldwell, Bentley Systems
Erick Heath, MWH Soft
Questions?