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The objective of this study is to compare the sustainability of current water systems when a dual water distribution system (WDS) is used for the non-potable water purposes of fire protection, irrigation, and toilet flushing. Sustainability of urban WDS is evaluated in terms of hydraulic efficiency and water quality. The first step is to assess sustainability of an example urban WDS by using sustainability index (SI). The SI is measured by reliability, resiliency, and vulnerability performance indices. Pressure and water age are selected as main parameters to determine sustainability. Once the SIs for pressure and water age are calculated by using the extended period simulation in the U.S. Environmental Protection Agency EPANET, these parameters are aggregated into an overall score (SIoverall). The critical areas are identified and improved by either adding network elements (i.e. pumps, valves) or adding a second WDS (i.e. reclaimed WDS) to serve for non-potable water demand. Fire flow is added to the modified WDSs and the SI is calculated again. The proposed methodology and application for SI calculation of WDS proved to be a credible approach in identifying poor performance areas and improving water services. A dual WDS for fire flow, irrigation and toilet flushing can assist in providing sustainable water utilities in urban areas meeting future needs. A linear programming procedure is used to determine the minimum cost of the branched dual WDS.


Session R50, Water Distribution Networks: Demand Forecasting



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