Semester of Graduation

Fall 2025

Degree

Master of Science (MS)

Department

Civil & Environmental Engineering

Document Type

Thesis

Abstract

While efforts are being made to curb the high rate of coastal land loss in Louisiana, and even to restore ecosystem services and functions, it is generally accepted that restoration of these areas and functions is not a one-to-one value. It may take decadal time scales to reach efficient functional processing of nutrients and carbon storage rates, which may never reach true capacity comparable to similar naturally-organized systems. Although it is imperative to preserve these areas, restoration of ecosystem services and biogeochemical processes of coastal wetlands are preferable to future without action scenarios. Effectively directing the use of the limited time and resources available is paramount, especially considering these efforts are taking place on such a large, coast-wide scale covering hundreds of square kilometers. Most notably, the strategic consideration and placement of marsh creation (MC) projects in relation to the hydrodynamic influences of sediment diversion operations can increase sediment trapping efficiencies in the receiving basin and can not only actively build coastal land in a sediment-poor area previously cut off from the Mississippi River (MR), but may also create marshes that can be sustained much longer than without the introduction of these sediments allowing coastal marshlands to survive pressures of relative sea level rise (RSLR) (Meselhe et al., 2017). While highly sophisticated models focus on longer time scales and larger areas, their elongated spin up time makes judging the progress of restoration projects on shorter time scales (< 25 years) more difficult. Numerical modeling programs, such as NUMAR, are valuable tools that can be utilized to determine potential outcomes of specified future environmental changes in parameters and calculated effects of restoration efforts, including the sustainability of MC projects. Here we were able to determine that, when coupled with real-world organic and inorganic sediment data from coastal wetlands experiencing the natural deltaic fluctuations of the MR, NUMAR predicted that five MC projects near the proposed Mid-Barataria Sediment Diversion (MBSD) within Barataria Basin would be able to net nearly 11 cm of vertical accretion and therefore survive the effects of RSLR, subsisting well beyond their projected 20-year life expectancy.

Date

10-29-2025

Committee Chair

Willson, Clint

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