AWWA DSS63741

This paper provides a comparison between the anticipated water quality (chlorine residual) in remote portions of water distribution systems and/or dead-end lines for conventional flushing versus Advanced Maintenance Flushing. It has been demonstrated, using a computer model that more frequent, smaller volume, periodic flushing events will provide for a consistent higher quality water in dead-end areas of distribution systems than is the case for less frequent, larger volume flushing events that take place between higher velocity flushing or water main cleaning events. Programmable devices, as manufactured by Hydro-Guard, allows implementation of the Advanced Maintenance Flushing scenarios identified in this paper, where otherwise it would be impractical from a manpower standpoint to implement this flushing strategy on a manual basis. A series of case studies identify that the benefits of Advanced Maintenance Flushing that were anticipated by water quality/hydraulic modeling are being accomplished throughout the United States. Currently hundreds of water systems are utilizing thousands of automatic flushing devices while implementing Advanced Maintenance Flushing. It is anticipated that as more water systems install automatic flushing devices and implement Advanced Maintenance Flushing that more will be learned about the benefits of this type of program along with information generated as to how to optimize both the design and operation of this type of program. Includes 10 references, tables, figures.