TIME-AVERAGING WATER-QUALITY ASSESSMENT

While reauthorization of the Safe Drinking Water Act is pending, many water utilities are preparing to monitor and regulate levels of distri bution system constituents that affect water quality. Most frequently, utilities are concerned about average concentrations rather than abou t tracing a particular constituent's path. Mathematical and computer m odels, which provide a quick estimate of average concentrations, could play an important role in this effort. Most water quality models deal primarily with isolated events, such as tracing a particular constitu ent through a distribution system. This article proposes a simple, tim e-averaging model that obtains average, maximum, and minimum constitue nt concentrations and ages throughout the network. It also computes pe rcentage flow contribution and percentage constituent concentration. T he model is illustrated using two water distribution systems, and resu lts are compared with those obtained using a dynamic water quality mod el. Both models predict average water quality parameters with no signi ficant deviations; the time-averaging approach is a simple and efficie nt alternative to the dynamic model.