SBCUD Water Modeling & Flushing Program | Blount County, TN

Often the most sustainable and fiscally responsible form of asset management is to make things new, rather than make new things. Unidirectional Flushing Programs (UDF), like the one Cannon & Cannon, Inc. developed for South Blount County Utility District (SBCUD), improve overall water quality. Better water quality has positive health and social effects for the communities involved.

Flushing a pipe that has become constricted, or better yet, preventing that pipe from ever becoming restricted in the first place, impacts a budget and the environment significantly less than manufacturing, transporting and installing a new pipe.

sbcud_image2Stretching from the southern border of Blount County at the Little Tennessee River to the northern border at the Tennessee River, SBCUD maintains four hundred and forty miles of pipe covering 132 square miles. To better understand hydraulic and water quality characteristics of the vast system, SBCUD contracted Cannon & Cannon, Inc. (CCI) to build, calibrate and maintain a model of the distribution system and use the model to develop a UDF.

CCI developed an interactive, tablet-based UDF program that will use systematic valve closing to force high velocity water through existing pipes in a designed sequence. The program will remove sediment and buildup from pipes; restoring hydraulic capacity, increasing available fire flows and improving water quality.

UDF programs also improve water quality. Removal of sediment from pipes can result in lower disinfection byproduct levels, decreased chlorine demand and improved appearance, smell and taste of water.

SBCUD employees operate the program electronically on tablets in the field. The result provides instantaneous feedback and on the fly corrections based on actual results. On top of that, the program assists SBCUD record keeping, water loss reporting, GIS mapping and model calibration.

Original or Innovative Applications of New or Existing Techniques


sbcud_imageThe tablet-based interactive UDF program adjusts in real time to what the operator is experiencing in the field, rather than the static form of output that other water modeling software packages provide. When the operator inputs the flow from a hydrant, the program notifies the operator whether the flushing velocity is achieved and how long to flush the line for required turnover of water.

For example, in a traditional flushing program, the model may calculate 1,000 gpm available flow at a hydrant, resulting in the need to flush for 20 minutes. An unaccounted for closed valve or changing demand patterns throughout the day could result in an actual flow of 900 gpm. CCI’s UDF program will immediately notify the operator whether 900 gpm provides adequate scouring velocity and that flushing time needs to be increased to 23 minutes.

In addition to assisting operators in the field, the data is immediately stored in a database which calculates unmetered water for water loss reporting. Other information related to chlorine residual and residual pressure are linked to GIS and the water model.

SBCUD’s UDF program continuously adapts, making calculations for the client and engineer instantaneously. The project is also an example of a paperless deliverable, utilizing growing mobile computer technology which can be re-used annually if updated to reflect infrastructure improvements. Furthermore, office work or data entry after flushing is eliminated as data is already in a usable electronic format.

SBCUD contracted CCI for a unidirectional flushing program, but received much more. They received:

  • A sophisticated, state of the art UDF program that can be used again and again each year
  • An accurate record of total volume of water flushed for water loss reporting purposes
  • Database of hydraulic and water quality data throughout the system that can be used to create maps, identify potential problem areas and further refine the water model

SBCUD can be absolutely certain they are flushing as efficiently as possible with zero wasted water and zero wasted time. SBCUD will notice water quality and hydraulic improvements without replacing or adding a single pipe.

SBCUD Water Modeling & Flushing Program