System Flushing

 

Components of a Distribution System Unidirectional Flushign Program

 

 

Aging/Decaying Pipes

Causes:

 

Results:

 

 

Why You Might Need a Flushing Program

In General In Particular

To Remove Impurities

  • accumulated
  • associated with new and repaired mains
  • associated with complaints
  • hazardous to the public health



 

  • Reduce
    • high bacterial concentrations
    • chemical contamination
    • turbidity
  • Remove
    • tastes and odors
    • discolored water
    • accumulated sediment
  • Respond to customer complaints
  • Increase chlorine residuals
  • Increase/maintain the life of mains

 

 

Flushing Strategies

 

Spot Flushing Reactive. Most common type of flushing. Used when there are local quality complaints
 
Stagnant Area Flushing Short term preventive. Used in areas with longer detention times (i.e. Dead-ends, low demand areas)
 
System-wide Flushing Long term preventive. Most comprehensive form of flushing. Maintains WQ and useful life of the mains.

 

 

 

Flushing Methods

 

 

Conventional Flushing

  • Water from all directions
  • Low flow velocities
  • Less scouring
  • Don't control flushing direction

 

 

 

 

Unidirectional Flushing

  • Water channeled
  • Higher flow velocities
  • More scouring/better cleaning
  • Systematic valve operation

 

 

 

 

Continuous Blow-off

  • Water "bled" at stagnant areas
  • Low flow velocities (< 1 fps)
  • Less scouring/poor cleaning
  • Large quantities of water used

 

 

 

 

"Traditional" Flushing

When:

 

How:

 

 

Unidirectional: Deciding When and Where to Flush

When: Time

 

Where: Location

 

 

What Data Will You Need?

 

 

Data Directly Related to Flushing Program

 

 

Data Indirectly Related to Flushing Program

 

 

Background Information Requirements

Do:

 

Do Not:

 

 

 

How Flushing Works (In The Field)

 

 

How Flushing Works (Program Administration)

Refinement/Redirection of Basis for Decision to Flush

Design Considerations When Extending the Distribution System

Program Champion

 

 

 

Elements of Unidirectional Flushing Program

The following elements go in a continuous cycle:

 

 

Staffing

The Flush Program Coordinator is responsible for:

 

The Flushing Crew is responsible for:

 

The Routining Crew is responsible for:

 

 

Why Use a Hydraulic Model?

Models are extremely valuable tools for planning, engineering and ops

"One size doesn't fit all" - each hydraulic system has unique characteristics, and there are different platforms available


Today's software is extremely sophisticated, and user friendly, but.....

 

The "Modeling Bar is Raising"

 

Models Migrating to GIS Interface

Distribution System Models are important tools now, but are only going to become more important

 

 

What are Benefits of Hydraulic System Modeling?

 

 

Creating a Hydraulic Model

Infrastructure: All Physical Facilities in System

 

Demands

 

Calibration

 

 

 

Data Used in Hydraulic Modeling