Stormwater Runoff - Modeling Impacts of Urbanization and Climate Change

Abstract

We developed a stormwater runoff modeling system that quantifies stormwater runoff in watersheds of the southeast coastal plain and is based on curve number and unit hydrograph methods of the U.S. Department of Agriculture, Natural Resources Conservation Services. We established a protocol for estimating runoff, calibrated the output, and then tested our system with U.S. Geologic Survey measured discharge and rainfall. Multi-site validation test results support the appropriateness of our calibration and the corollary that our stormwater runoff simulations are reasonable for our target watersheds. The modeling system is robust and flexible, and parameters can be changed in order to explore diverse aspects of stormwater runoff including comparing runoff among watersheds at different stages of urbanization; projecting changes in a watershed’s runoff with increased development; and looking at runoff volume within the context of impervious cover, changing patterns of precipitation, and antecedent runoff conditions by using a broad range of climate change and land use scenarios. Our modeling system provides a powerful tool for scientific research and for coastal resource management and decision making in the southeast specifically, and it can be applied to other regions by recalibrating parameters that reflect regional characteristics. The system also can serve as a community science education tool for the general public with an interest in understanding changes in runoff in the context of urbanization and climate change.