Flood Mitigation in Roanoke’s Central Business District

Don Rissmeyer, PE, CFM, Associate, A. Morton Thomas & Associates, Inc. (AMT)

The City of Roanoke’s Central Business District (CBD) is an economic hub, and its long-term sustainability and resiliency is vital to the Commonwealth, however, the CBD is subject to flash flooding during intense rainfall since it sits atop the confluence of two major streams – Trout Run and Lick Run.  These streams are conveyed under city streets in large drainage tunnels dating back to the 1880s, prior to modern engineering standards.

This engineering study provides a preliminary evaluation of historic flooding and compares traditional and emerging practices in flood mitigation to establish recommendations that will reduce or eliminate flood risks. Recommendations are based on the 25-Year Storm Event using both a 1-hour “Flash Flood” and a larger 24-hour duration storm event.  PC-SWMM modeling forms the basis for existing conditions evaluations and proposed strategies.

Additionally, this study promotes water quality improvement in the solutions presented, where it is feasible to foster a green approach, shared community vision, and public support for a resilient future.  The implementation of this flood mitigation plan is the “next great challenge” for the City of Roanoke’s Stormwater Utility Team and this study provides a road map ahead.

Author Bio

Don Rissmeyer is a licensed Professional Engineer in multiple states and a Certified Floodplain Manager with more than 30 years of experience in providing consulting engineering services to municipal stormwater clients at the local, state, and federal levels. He is a Past-President of the Virginia Section of ASCE and the Virginia Floodplain Management Association, and a member of the Virginia Municipal Stormwater Association, the Western Virginia Floodplain Network, and the Joint Legislative Committee for ACEC Virginia.