Influence of Sea Level Rise on a Coastal Barrier System and Its Reliability Against Future Storm Surges in the Houston-Galveston Area, Texas

Abstract

The Ike Dike is a concept of coastal barrier system designed to protect the Houston-Galveston area (HGA), which is highly susceptible to flood risks from storm surges. The barrier system has been proposed with different alignments and configurations: movable, permanent, and extended permanent barrier systems. We have evaluated and compared the feasibility of three barrier types as a function of sea level rise (SLR), taking into account the reliability of the movable barrier. We employ the Delft3D Flexible Mesh suite to simulate storm surges in a hydrodynamic model, incorporating pressure and wind velocity fields spatialized by the Holland’s model from synthetic storm tracks. Simulations are driven by a range of SLR projections and synthetic storm tracks, with different barrier types. Probabilistic flood depths are predicted for specific return periods by fitting the 30-year maxima flood depths from the simulations to a probability distribution function. Using the CoreLogic database of residential properties in the HGA and building damage functions, we calculate probabilistic flood damages for each predicted flood depth. This allowed us to quantify flood risk as the expected annual damage, integrated over a range of return periods. Our results indicate that the permanent and extended permanent barrier systems are more effective at mitigating storm surge risk than the movable barrier system. Moreover, the necessity of the extended permanent barrier system becomes more significant as SLR increases.