Storm Water Management Model (SWMM): Performance Review and Gap Analysis

The Storm Water Management Model (SWMM) is a widely used tool for urban drainage design and planning. Hundreds of peer-reviewed articles and conference proceedings have been written describing applications of SWMM. This review focused on collecting information on model performance with respect to calibration and validation in the peer-reviewed literature. The major developmental history and applications of the model are also presented. The results provide utility to others looking for a quick reference to gauge the integrity of their own unique SWMM application. A gap analysis assessed the models’ ability to perform water quality simulations considering green infrastructure (GI)/Low Impact Development (LID) designs and effectiveness. We conclude that the level of detail underlying the conceptual model of SWMM versus its overall computational parsimony is well balanced – making it an adequate model for large and medium-scale hydrologic applications. However, embedding a new mechanistic algorithm or providing user guidance for coupling with other models will be necessary in order to realistically simulate diffuse pollutant sources, their fate and transport, and the effectiveness of GI/LID implementation scenarios.