Flooding outside the floodplains: Evaluating pluvial flooding in the Ellerbe Creek Watershed

Abstract

Flood-related policies and programs have historically focused on riverine and coastal flooding, overlooking the potential impact of pluvial flooding. Pluvial flooding occurs when the rainfall rate exceeds the capacity of the ground to absorb water and/or drainage systems’ ability to carry away water. This process is exacerbated in our increasingly urban landscapes where impervious surfaces preclude infiltration of rainfall into the ground. This project aims to encourage stakeholders to invest in studying and managing pluvial flooding through two objectives: 1) Identifying areas prone to pluvial flooding in the Ellerbe Creek Watershed using EPA’s Stormwater Management Model (SWMM) and 2) integrating the pluvial flood map into the ongoing watershed protection projects of our client, the Ellerbe Creek Watershed Association (ECWA), by building a GIS-based Strategic Planning Tool using R software. This work reflects ECWA’s mission statement to move Durham to be an example for proactive urban stormwater management.