Miller Creek Stormwater Modeling

Abstract

The US EPA’s Stormwater Management Model (SWMM) was used to model stormwater runoff volumes and pollutant concentrations in Miller Creek, located in Duluth, Minnesota. The quantity model was calibrated and validated with two years of hourly gage data for three sites along the creek. The quality model had minimal calibration from pollutant loading data for four subcatchments, and was meant for use as a comparative tool to analyze relative changes in pollutants based on various scenarios. As expected, commercial and industrial areas with high amounts of impervious surfaces had a significant impact on the flow volumes, resulting in higher, flashier peaks than undeveloped portions of the watershed. Of the four pollutants modeled (total dissolved solids, total suspended solids, nitrate-Nitrogen, and total Phosphorus), developed areas contributed the majority of all pollutants.