Modeling on the Beach: Stormwater Master Planning for Coastal Resiliency
The City of Virginia Beach is a low-lying, coastal area subject to tidal flooding, high groundwater, poor soils, and little topographic reliefs. Portions of the City flood from relatively minor storm events, and without intervention, flooding is expected to worsen as sea levels rise and storms become more intense.
The City is in the process of developing Stormwater Master Plans (SWMPs) for each basin to identify areas most prone to flooding and prioritize projects based on cost, efficacy, and a variety of social impact factors. WSP was tasked with developing a SWMP for the Eastern and Western Lynnhaven River drainage basins which contain nearly 200 simulated flooding areas (SFAs) spanning over 11 square miles.
In order to resolve flooding, PCSWMM and GIS simulations were utilized to analyze and evaluate alternatives which include BMPs, retrofits, pump stations, conveyance systems, and innovative project phasing. This presentation examines case studies from the SWMP, highlighting the approaches taken to identify the strongest alternatives based on the City of Virginia Beach’s Alternative Selection Criteria (ASC) and Project Performance Criteria (PPC). These scores, along with project descriptions, GIS simulated flood reduction maps, and cost estimates, were combined to form a SWMP that helps inform both policymakers and citizens of the costs, impacts, and benefits associated with each project.
Author Bio
Justin Twine is a water resource engineer with more than 13 years of experience working in H&H modeling, stormwater management, and site/road/bridge design projects. Through these projects, Justin has become a technical expert in H&H analysis, BMP and LID designs, stormwater permitting, and floodplain mitigation. Behirah Hartranft is an associate consultant with over 4 years of experience with a focus in stormwater modeling. She has her bachelor’s and master’s degrees in biological engineering from the University of Missouri. When she’s not mitigating flooding, you can catch her riding horses or hanging out with her pet parrot. Catherine Mellette is an assistant consultant with over 2 years of experience with a focus in stormwater management. She has a bachelor’s degree in environmental engineering from the Georgia Institute of Technology. She spends her free time at local coffee shops and is halfway to her goal of visiting every Virginia State Park.
