WinSLAMM History

The Source Loading and Management Model (SLAMM) was initially developed to more efficiently evaluate stormwater control practices. It soon became evident that in order to accurately evaluate the effectiveness of stormwater controls at an outfall, the sources of the pollutants or problem water flows must be known. As a Windows based program, WinSLAMM has evolved to include a variety of source area and end-of-pipe controls and the ability to predict the concentrations and loadings of many different pollutants from a large number of potential source areas. WinSLAMM calculates mass balances for both particulate and dissolved pollutants and runoff flow volumes for different development characteristics and rainfalls. It was designed to give relatively simple answers (pollutant mass discharges and control measure effects for a very large variety of potential conditions).

WinSLAMM was developed primarily as a planning level tool. Its primary capabilities include predicting flow and pollutant discharges that reflect a broad variety of development conditions and the use of many combinations of common urban runoff control practices. Control practices evaluated by WinSLAMM include detention ponds, infiltration devices, porous pavements, grass swales, catchbasin cleaning, and street cleaning. These controls can be evaluated in many combinations and at many source areas as well as the outfall location. WinSLAMM also predicts the relative contributions of different source areas (roofs, streets, parking areas, landscaped areas, undeveloped areas, etc.) for each land use investigated. As an aid in designing urban drainage systems, WinSLAMM also calculates correct NRCS curve numbers that reflect specific development and control characteristics. These curve numbers can then be used in conjunction with available urban drainage procedures to reflect the water quantity reduction benefits of stormwater quality controls.

WinSLAMM is normally used to predict source area contributions and outfall discharges. However, the model has been used in conjunction with SWMM to examine the ultimate receiving water effects of urban runoff. A more refined version of a SLAMM-to-SWMM interface processor is currently under development.

The development of SLAMM began in the mid 1970s, primarily as a data reduction tool for use in early street cleaning and pollutant source identification projects sponsored by the EPA's Storm and Combined Sewer Pollution Control Program (Pitt 1979; Pitt and Bozeman 1982; Pitt 1984). Additional information contained in WinSLAMM was obtained during the EPA's Nationwide Urban Runoff Program (NURP) (EPA 1983), especially the Alameda County, California (Pitt and Shawley 1982), the Bellevue, Washington (Pitt and Bissonnette 1984), and the Milwaukee (Bannerman, et al. 1983) projects. The completion of the model was made possible by the remainder of the NURP projects and additional field studies and programming support sponsored by the Ontario Ministry of the Environment (Pitt and McLean 1986), the Wisconsin Department of Natural Resources (Pitt 1986; Bannerman, et al. 1996; Legg, et al. 1996), and Region V of the U.S. Environmental Protection Agency. Early users of WinSLAMM included the Ontario Ministry of the Environment's Toronto Area Watershed Management Strategy (TAWMS) study (Pitt and McLean 1986) and the Wisconsin Department of Natural Resources' Priority Watershed Program (Pitt 1986). Many WinSLAMM user's have incorporated the use of the model with a GIS (Thum, et al. 1990; Kim, et al. 1993; Kim and Ventura 1993; Ventura and Kim 1993; Bachhuber 1996; Haubner and Joeres 1996). Environment Canada funded basic stormwater research data that was incorporated in the model; the Tennessee Valley Authority funded use of the model to evaluate land development scenarios and addition of many rain files; the Stormwater Management Authority of Jefferson County, Alabama funded economic analysis and in-stream model integration; the City of Madison, Wisconsin and the USGS funded the addition of the high efficiency street cleaning processes; the Wisconsin Department of Natural Resources funded the addition of the proprietary small gravity separators framework; and ADS, Contech Engineered Solutions,and Hydro International are supporting the addition of filtering devices.

WinSLAMM can now be effectively used as a tool to enable watershed planners to obtain a better understanding of the effectiveness of different control practice programs.

A logical approach to stormwater management requires knowledge of the problems that are to be solved, the sources of the problem pollutants, and the effectiveness of stormwater management practices that can control the problem pollutants at their sources and at outfalls. WinSLAMM is designed to provide information on these last two aspects of this approach.

WinSLAMM Development and Release Notes