Long Time-Series Simulation of Water Quality in Distribution Systems

Dynamic (extended period simulation) models have largely replaced steady-state models for simulation of water quality in distribution networks. Dynamic modeling generally has been limited to periods of a day or a few days. This paper describes three modeling studies that used long time-series analyses to characterize contamination in the water distribution system of a major city. Continuous runs of the EPANET model, each covering a period of one year, were used to develop matrices that could be used to calculate average annual dosages at each node in the distribution system for a wide variety of contaminant concentrations at the source. The matrix approach provided a way to facilitate integration of ground-water modeling results with distribution modeling. The use of long-term runs overcomes the shortcomings of steady-state modeling or use of "representative days" in predicting long-term average concentrations.