Stormwater runoff can transport nutrients, sediments, chemicals, and pathogens to surface water bodies. Managing runoff is crucial to preserving water quality in rapidly developing urban watersheds like Northwest Arkansas. A watershed containing much of the University of Arkansas campus was identified as the target area for this study because stormwater from this location drains into the West Fork of the White River, designated as an impaired water body due to siltation. The project objective was to develop a methodology to test existing stormwater drainage infrastructure, identify potential areas of improvement, and estimate potentially contaminated runoff by combining two widely used prediction models. The U.S. Department of Agriculture's Natural Resource Conservation Service's curve number (CN) method was used to estimate runoff depths and volumes, while a flow-direction model integrated topography, land use, and stormwater drainage infrastructure in a geographic information system. This study combined the CN and flow-direction models in a single geodatabase to develop flow direction/quantity models. Models were developed for 5-, 10-, 25-50-, and 100-year floods and varied by the antecedent moisture content. These models predicted flow directions within existing drainage infrastructure, runoff volumes for each flood, and a hypothetical flood analysis model. Results showed that between 24,000 m3 (5-year flood) and 60,000 m3 (100-year flood) of runoff would be transported to the West Fork of the White River. The methodology developed and results generated will help stormwater planners visualize localized runoff, and potentially adapt existing drainage networks to accommodate runoff, prevent flooding and erosion, and improve the quality of runoff entering nearby surface water bodies.
Koehn, K. M. (2008). Runoff Using a Combined Geographic Information System and Curve Number Approach. Inquiry: The University of Arkansas Undergraduate Research Journal, 9(1). Retrieved from https://scholarworks.uark.edu/inquiry/vol9/iss1/10