ASA Southern Branch 2008 Annual Meeting
February 3-5, 2008
Dallas, TX
Monday, February 4, 2008 - 10:50 AM
Stormwater Runoff Analysis for the University of Arkansas Campus Area.
Keshia Koehn, Univ. of Arkansas CSES Club, 1766 N Gregg, Apt. 16, Fayetteville, AR 72701
Stormwater runoff accumulates and transports nutrients, sediments, chemicals, and pathogens to surface water bodies. This study sought to develop a methodology to improve existing University of Arkansas campus stormwater drainage infrastructure by combining two widely-used prediction models. The USDA Natural Resource Conservation Service Curve Number (CN) Method calculated quantitative runoff values using soils, land-use, and precipitation data. The flow direction model, as defined here, integrated topography, hydrography, and stormwater drainage infrastructure in a Geographic Information System (GIS) to produce a map of runoff flow direction. This study merged the CN and flow direction models in a single geodatabase to develop a runoff model that provided information about the quantity of water. The area of study was defined as the watershed which contained the majority of the University of Arkansas campus. Runoff from this watershed drains into the West Fork River, a tributary of the White River and Beaver Lake. Currently, the West Fork River is exceeding TMDLs for turbidity, harming its freshwater habitats. Varied by the Antecedent Moisture Content (AMC), three models were developed for 5, 10, 25, 50, and 100 year flood precipitation conditions. These models contained the runoff flow direction within the existing stormwater drainage network, the total volume of runoff associated with each flood, and a hypothetically confined flood analysis model. It was found that between 11,000 m3 (1” rain) and 650,000 m3 (100 year flood) of water for a single storm event would runoff into the West Fork River, quality unknown. Given the rate of expansion and development at the UofA, results would help planners to better visualize runoff quantities, adapt existing drainage networks to accommodate stormwater runoff, prevent localized flooding, and decrease soil erosion. Hopefully, with the advent of cost-effective monitoring programs, the quality of runoff entering the West Fork can be increased.