Development of a Mathematical Model for Urban Runoff Quantity and Quality

Abstract

An urban runoff model has been developed for the simulation of stormwater quantity and quality. The model consists of a quantity submodel and a quality submodel. The quantity submodel utilizes the Linearized Subhydrographs Method to simulate runoff hydrographs for recorded and synthetic storm events. The method is based on a simplified concept where hydrographs are generated for each sub-catchment in accordance with the duration of the rain and the time concentration. The quality submodel consists of determination of stormwater pollution levels. In the simulation of pollutant removal process, a relationship signifiying the effect of incremental runoff volume and the effect of the depth of flow upon pollutant removal efficiency is incorporated. Accuracy of the model is then tested by applying the model to urban watersheds with recorded rainfall, runoff and quality data. The model may be used as an alternative to the more comprehensive and complex models in the planning and analysis of stormwater systems.