WinSLAMM

WinSLAMM calculates runoff and BMP effluent concentration using algorithms and unit processes specific to each type of structural BMP For catch basin cleaning, the model requires the user to identify specific parameters such as total number of basins or basin density and clean out dates or frequency. Pollutant removal assumptions associated with this BMP is not detailed in model documents, likely due to proprietary reasons. For street cleaning, the model requires the user to identify specific parameters such as street cleaning dates or frequency, type of cleaner (e.g., mechanical or vacuum), and parking densities (e.g., light, medium, extensive, none) for land area type (commercial, residential, etc.). Pollutant removal assumptions associated with this BMP is not detailed in model documents, likely due to proprietary reasons. WinSLAMM does allow user to simulate other BMPs by entering the percent pollutant concentration reduction and fraction of the area treated. The percent reduction will be applied uniformly to the pollutant load and runoff volume generated.

Assuming default parameter files are used and not modified, the following are required values to be entered directly into the program: source area (in acres) of each land use (i.e. the area of roofs, sidewalks, parking lots, etc.), and BMP properties (i.e. catch basin size, cleaning frequency, fraction of catchment served, etc.).

WinSLAMM can predict runoff volumes and pollutant loadings for one or many years of default rainfall data. Output is in the form of a report that can be saved as a text or Microsoft Excel file, which includes: runoff volume and pollutant concentrations, land use output totals, continuous hydrograph with event mean pollutant concentration, and BMP capital and maintenance costs.

• Tool may be used during the planning phase of stormwater program
• WinSLAMM is based on small storm hydrology concept. Under this concept, the majority of the runoff volume and pollutant loadings in urban areas is a result of the small and medium rainfall events
• This tool is not suitable for modeling agricultural areas, natural areas, etc.
• The model is prepopulated with parameter files for the following regions of the US: northwest, southwest, central, Great Lakes, southeast, East Coast
• The user can add more water quality constituents by modifying the parameter files
• Uncertainty is accounted for statistical Monte Carlo functionality if enabled WinSLAMM is limited to stormwater modeling and does not factor dry weather flows or receiving water processes
• WinSLAMM may be used in conjunction with in-stream models to capture removal and/or transformation of pollutants in-stream
• Tool may be used in conjunction with drainage design models to incorporate the mutual benefits of water quality controls and drainage design
• WinSLAMM can consider many storm water controls together (affecting source areas, drainage systems and outfalls) for a long series of rains
• Tool does not currently model mass erosion from pervious areas or construction sites.
• WinSLAMM has a database format allowing each model file to be opened in a database program such as Microsoft Access
• Free for municipal staff through a verification, otherwise, $375 per license ($200 for a renewal)
• Requires Microsoft Access if the user wants customized parameter files
• A series of videos are available that explain how to set up the model on www.winslamm.com