Modeling Stormwater Storage/Treatment Transients: Applications

The transient response of stormwater storage/treatment systems to variable forcing functions of flow and concentration is determined for completely mixed systems of constant and variable volumes and for one-dimensional advective systems with dispersion, from previously derived mathematical models, and results are compared. Frequency analyses are performed on input and output concentrations and mass rates for a single event and for all wet weather events during the year of record. The unifying concept of continuity is extended to determine the receiving water response to providing variable detention times in a well-mixed constant volume stormwater storage facility, while maintaining secondary treatment of dry weather flows. Applications to the Humboldt Avenue detention tank, Milwaukee, Wisconsin and Des Moines, Iowa are presented.