Facilitating Coastal Stormwater Management in North Carolina: Runoff Estimation and Institutional Education

In coastal North Carolina, increased surface runoff from urban, agricultural, and forestry development contaminates coastal waters and has led to extensive shellfishing area closures. Coastal communities looking to restore their waters become eligible for restoration funding when they complete watershed restoration plans with numeric pollutant reduction goals. In this work, I present a new geospatial analysis tool for calculating modern and historic stormwater runoff estimates, which can be used as proxies for restoration goals. This tool uses satellite-derived land cover, soils, and precipitation data to provide stormwater estimates using a watershed boundary as the minimum required input. Additionally, to improve the accuracy of estimates, the tool has optional inputs for the proportion of impervious surface that is disconnected in the watershed and for areas drained for forestry operations. I compare the results from this estimator with the more labor intensive methods used in previous stormwater management plans and with estimates from SWARM (Stormwater Runoff Modelling System), recently developed by NOAA. Finally, I provide recommendations for how to best integrate these tools into the current management framework.