Sea-Level Rise Effects on Storm Surge and Nearshore Waves on the Texas Coast: Influence of Landscape and Storm Characteristics

Abstract

Sea-level rise (SLR) estimates vary broadly, but most estimates predict significant increases in sea levels within the next century. Through the use of validated, coupled wave and hydrodynamic models, this study investigates SLR effects on storm surge and nearshore waves, including variation with coastal landscape type and storm characteristics. Both the wave and hydrodynamic models account for bottom friction based on land-use type, so the modeling procedure accounted for SLR-related changes to land cover, in addition to higher mean sea levels. Simulation of storms with similar meteorological characteristics and track but with landfall in the northeastern and southwestern coastal areas allowed examination of how the coastal features influenced the storm surge and wave response to increased sea levels. The simulation results analyzed here demonstrate that the relationship between storm surge and relative SLR (RSLR) varies between geographic region and storm scenario. The increase in an inundated area is linear in the north, and in the south, the inundated area approaches the northern values for similar storms asymptotically. Nearshore wave results indicate, as expected, that larger water depths created by positive RSLR and amplified surge allow larger waves to propagate into inland areas. For the Texas simulations, it was found that an increase in hurricane wind speeds of 25% is approximately equivalent to a RSLR of 0.5 m in terms of increased area of inundation impact. Because of the complexities of storm-surge dependency on storm strength, track, and local topography, there is no one-size-fits-all response to RSLR descriptive of all locations. Site-specific computer modeling should be used to evaluate the risk facing coastal communities.