Two‐Stage Urban Runoff Forecast Model

Storm‐related pollution in general, and combined sewer overflows in particular, have been found to contribute significant amounts of pollutants to receiving water bodies. Control of pollution from these nonpoint sources of pollution is very costly. Accordingly, integrated real‐time control of combined sewer overflow is being considered as a possible alternative to the more traditional forms of pollution control. The basic features of suggested control combined sewer overflow control strategies are reviewed, including simple local control, reactive control, and anticipatory control. Because water quantity forecasts are essential to any integrated real‐time control strategy, the application of a simple microcomputer‐based two‐stage urban runoff forecast model is examined. Runoff forecasts from this deterministic‐stochastic model are provided for lead times ranging from 1–12 time steps (5–60 min). The two‐stage approach is found to be particularly useful for lead times of up to 30 min.