Estimating the economic vulnerability of 2020–2099 storm flooding with sea level rise on Coastal Virginia

Abstract

Estimating the economic impact of flooding is an essential element of flood risk management. Policy interventions to mitigate the impact of flooding must be balanced against the financial and economic costs of flooding. Using projections of sea level rise for 2040, 2060, and 2080 and estimates of flooding damage that are equaled or exceeded 10-, 50-, 100-, and 500-year period, we investigate the financial costs of flooding across eight planning districts in Coastal Virginia. We briefly discuss the methodology to estimate the average annualized loss (AAL) given discrete events and likelihoods and how these AALs flow into the estimation of the net present value of flooding in Coastal Virginia. The Hampton Roads metropolitan area accounts for approximately 80.7% of estimated nominal losses currently, rising to 88.1% by 2080 due to sea level rise. This vulnerability is linked to poorly planned development, population growth, ground subsidence, and economic inequities. The present value of unmitigated flooding ranges from $20.0 billion to $58.7 billion in 2021 dollars, depending on the discount rate. Discounted economic impacts for unmitigated sea level rise could reach $82.9 billion for Coastal Virginia this century. The concentration of costs in Hampton Roads, which produces 20% of Virginia's GDP, underscores the need for targeted economic and security policies.