Doctor of Philosophy (PhD)
Civil and Environmental Engineering
The hurricane storm surge analysis presented in this dissertation examines surge response to changes in the Louisiana coastal landscape and Gulf of Mexico water level from 1850 to 2110. Land to water (L:W) isopleths, lines depicting areas of constant land to water ratio along the modern Louisiana coast, are utilized in the development of a simplified storm surge model that closely reproduces the surge output of a state-of-the-art detailed model. Eleven comparable storm surge models are constructed with each featuring a representation of the Louisiana coastal landscape circa 1850, 1890, 1930, 1970, 1990, 2010, 2030, 2050, 2070, 2090 and 2110. Each storm surge model is forced with the same suite of historical hurricane wind and pressure fields and contemporaneous global mean sea level scenario. Differences in storm surge characteristics are quantified and analyzed. Four distinct stages in the evolution of coastal Louisiana are identified: 1. 1850-1890: Minimal to no change in both landscape and storm surge heights; 2. 1890-1930: Increased surge heights in the Atchafalaya-Vermilion, Terrebonne and Barataria coastal basins due to disappearance of coastal forests and excavation of Wax Lake Outlet; 3. 1930-2010: Minimal change in surge heights in the Atchafalaya-Vermilion coastal basin relative to adjacent Terrebonne and Barataria coastal basins due to emergence and growth of the Wax Lake and Atchafalaya Deltas; 4. 2010-2110: Drowning of all three coastal basins due to future global mean sea level (GMSL) rise and subsidence. Lafitte, Louisiana, demonstrates the coastal community-scale impact of past and future relative sea level rise. Established in 1730, this area did not begin to regularly flood until 2010 following substantial wetland collapse between Lafitte and Barataria Bay. After nearly 300 years of existence, a comprehensive flood risk reduction system is no longer financially feasible for this coastal community. However, projecting the configuration of the Louisiana coastal landscape and surge response through 2110 enables more effective long-term planning for coastal communities such as Lafitte.
Siverd, Christopher George, "Coastal Louisiana Landscape and Hurricane Storm Surge Evolution 1850 - 2110" (2019). LSU Doctoral Dissertations. 4845.