Publication Date



geographic information systems, runoff, mitigation, treatment


SWAMP GIS is a spatially-based decision support system that empowers users in rural areas within Oregon (USA) with tools for predicting and mitigating stormwater runoff. SWAMP GIS is made freely available to all potential users that have an Internet connection. Users can choose from among six maximum 24 hour runoff events and can calculate runoff statistics for a specific area that they trace on top of a digital orthophotograph, or from a contributing area that can SWAMP GIS can create based on a user-specified point or polygon. Predicted stormwater runoff for the area of interest is based on Natural Resources Conservation Service methodology and involves spatial databases representing rainfall amount, landscape terrain, hydrologic soil groups, and land cover categories. SWAMP GIS users can then use a runoff reduction tool to investigate the affects of 17 different stormwater runoff mitigation strategies. The runoff reduction tool can assist in determining which runoff mitigation strategy might be most advantageous given the characteristics of the landscape surrounding an area of interest. SWAMP GIS brings spatial technology and approaches for stormwater runoff prediction and reduction to users that might otherwise lack the GIS resources and expertise necessary for stormwater analysis. We describe the SWAMP GIS decision support tool and the design of spatial geoprocessing tools for runoff estimation. We also provide examples of tool applications for predicting and mitigating storm water runoff within rural areas.