Model archive for analysis of the effects of impervious cover on receiving-water quality with the Stochastic Empirical Loading Dilution Model (SELDM): U.S. Geological Survey data release

Document Type



Published in: USGS: Science for Changing World, 2020.


Impervious runoff-discharge to receiving streams is widely recognized as one of the leading factors contributing to ecological degradation in such streams. Although there are many factors that contribute to ecological degradation with increasing development adverse effects caused by runoff quality is widely recognized as a contributing factor. The objective of this study was to simulate the flows concentrations and loads of impervious-area runoff and stormflows from an undeveloped area over a range of impervious percentages and drainage areas to examine potential relations between these variables and the quantity and quality of downstream flows. Stormwater runoff in a hypothetical stream basin that represents hydrologic and physiographic basin properties in southern New England was simulated using the Stochastic Empirical Loading and Dilution Model (SELDM) to do a numerical experiment designed to explore relations between impervious cover and receiving-water quality. These simulations included a range of impervious cover from 0.1 to 30 percent. These relations were examined to provide planning-level estimates of a population of concentrations and dilution factors as explanatory variables for the changes in stream biota commonly seen as the percentage of impervious areas increase. SELDM is a runoff-quality model developed by the U.S. Geological Survey in cooperation with the Federal Highway Administration to simulate the adverse effects of runoff on receiving waters and provide meaningful information about the potential effectiveness of management measured to reduce water quality risks. This is a model archive for these numerical experiments documenting the input statistics and the simulation results. Model development files include details of simulated hydrology, basin properties, upstream undeveloped area water quality, and developed (impervious area) area runoff quality. Model results include downstream water quality with and without structural best management practices.