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This paper identifies the benefits that two Oregon cities obtained from computerized water distributionmodels, used to prepare for the Stage 2 Disinfectants/Disinfection Byproducts (D/DBP)Rule and to identify operation improvements. These benefits include lessons learned from twosuccessful dynamic simulation (or so-called "extended-period") modeling projects, as applied towater distribution systems. CH2M HILL and two Oregon utilities, Eugene Water and ElectricBoard (EWEB) and the City of Albany, took advantage of GIS applications, field work,SCADA, and hydraulic modeling to plan system improvements.EWEB, with a service area population of approximately 160,000, and the City of Albany, with aservice area population of 43,000, both recognized the importance of using an extended periodsimulation (EPS) model to conduct the Initial Distribution System Evaluation (IDSE), requiredby the Stage 2 D/DBP Rule. Both utilities saw the first step as building and using an EPS tolocate areas of high water age in their distribution systems.This paper provides key points to help water utility managers understand how two utilitieschose to upgrade their existing steady-state models to dynamic models, with an eye towardsmeeting the new IDSE regulations. Challenges, benefits, and costs of the field work and theprocedures for calibrating the models are described. For the field work procedures, pump flowsand tank water surface changes measured by SCADA provided hourly changes in systemdemand over a period of 24 to 72 hours. Examples provided in this paper include how themodels represented the actual water distribution system fluctuations during low demand periods,when water becomes stagnant in tanks and pipelines. The models help identify ways to reducethe water age and improve water quality. Includes tables, figures.

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Edition: Vol. - No. Published: 06/17/2005 Number of Pages: 16File Size: 1 file , 720 KB