REDEVELOPMENT OF THE US EPA STORMWATER MANAGEMENT MODEL

The US EPA's Water Supply and Water Resources Division has partnered with the consulting firm of CDM to redevelop and modernize the Storm Water Management Model (SWMM) software. SWMM's computational engine has been completely rewritten using an object-based approach. Most existing modeling features have been kept and several new ones added. Special efforts were made to enhance the numerical stability of SWMM's dynamic wave flow routing routine. A rigorous Quality Assurance program was pursued to insure that results from the new SWMM matched those of the old SWMM or that reasons for any differences were justified. In addition, a graphical user interface was added to SWMM. It allows users to graphically edit system elements on a visual map of the drainage area and to view simulation results in a variety of formats such as time series plots and tables, profile plots, scatter plots, histograms, and statistical frequency tables. The revamped SWMM remains as public domain software and can be obtained from http://www.epa.gov/ednnrmrl/swmm.