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This paper discusses how water distribution system computer models can be used to assess and improve theeffectiveness of conventional flushing programs. Using the model, flow rates for eachhydrant are simulated to predict pipeline flow velocities. Model output is then analyzedto identify pipeline segments that do not achieve the target flushing velocity. The targetflushing velocity can vary from system to system and may depend on the flushingprogram objectives. The length of pipeline segments that do not achieve the desiredflushing velocity compared to the total length of pipeline in the system provides anestimate of the efficiency of the conventional hydrant flushing program. The model canalso be used to develop specific procedures for improving the flushing effectiveness byincreasing the flow velocity in areas of the system that would not otherwise achieve thedesired flushing velocity. For example, the model can predict how opening additionalhydrants and/or strategically closing valves could increase flow velocities in certainpipes. Directional or other special flushing procedures can be implemented based on themodel results, to improve flushing effectiveness for specific areas of the system. Theprimary advantage of this system flushing approach is that the utility only performs morecostly flushing techniques in areas of the system where they are required to achieveflushing velocity goals. In addition to optimizing pipeline flow velocities to maximize the flushing programeffectiveness, the hydraulic model can be used to predict minimum system pressures thatwill occur during the flushing event, to help ensure that minimum system pressurerequirements are maintained, and to establish key pressure monitoring locations. Inaddition, the model can be used to help establish flushing routes based on normal flowdirections. Includes 3 references, table, figures.

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Edition: Vol. - No. Published: 09/29/2004 Number of Pages: 9 File Size: 1 file , 330 KB