HRI Lecture Series - Dr. James Gibeaut - "Living with Sea Level Rise on the Texas Coast"

"Living with Sea Level Rise on the Texas Coast"

DR. JAMES GIBEAUT
ENDOWED CHAIR FOR GEOSPATIAL SCIENCES
HARTE RESEARCH INSTITUTE FOR GULF OF MEXICO STUDIES

The Texas Coast consist of barrier islands, lagoons, and estuaries on a broad coastal plain. Sea level rise (SLR) has a significant impact on the region because of low-lying and gently sloping topography, land subsidence, low sediment supply, estuary tide ranges less than 0.3 m, and exposure to hurricanes. Communities embedded in this dynamic system must consider environmental and socio-economic conditions as they exist today but also must plan for future change to be resilient. Landscape change models, which project where coastal environments such as marshes, flats, and upland areas will transition as sea level rises, provide valuable information for proactive planning. Combining this information with storm surge models showing areas vulnerable to flooding and damage reveals current and potential vulnerabilities.

The Sea Level Affecting Marshes Model (SLAMM) was used to predict landscape changes under two scenarios: 0.5-meter and 1.5-meter global mean SLR by 2100. The model predicts 527 to 1,129 square miles of coastal land loss by 2100 if no mitigating actions are implemented. Nineteen hypothetical hurricanes, varying in size, track, speed, and categories ranging from 1 to 3, were simulated using the coupled ADCIRC+SWAN models on 2100 landscapes produced by SLAMM. Results show inland storm-surge penetration increasing by up to 10 miles and the amount of area inundated 2 to 3 times larger with future changes caused by SLR. Economic modeling (HAZUS-MH) estimated the potential costs of storm damage to buildings and related costs under both present and future conditions. Because of SLR, cumulative damages from 5 category 2 hurricanes, each striking a portion of the Texas coast, increases by $15 billion to $40 billion over present conditions.

The Texas coast varies in how SLR and storms will impact natural and human environments in the future. Overall, the upper coast is most susceptible to environmental and economic impacts, but there are vulnerabilities in every estuarine system. The model output can guide where conservation, protection, restoration, or policy are most needed and may succeed.

Dr. James Gibeaut is the Endowed Chair for Coastal Geospatial Sciences at the Harte Research Institute for Gulf of Mexico Studies at Texas A&M–Corpus Christi. His research focuses on tracking and understanding coastal change and projecting future impacts of storms and sea level rise. Dr. Gibeaut places the results of his research in the context of improving coastal resiliency and often advises on coastal policy and management issues.