Semester of Graduation
Summer 2025
Degree
Master of Science (MS)
Department
Oceanography and Coastal Science
Document Type
Thesis
Abstract
The Mississippi River Delta and southeastern Louisiana have entered a stage of retrogradation due to natural and anthropogenic processes. Damming within the Mississippi Basin, subsidence, and erosion are some major factors leading to land loss. The decreased sediment load has caused land loss in both subaerial and subaqueous environments. Waves are one of the major factors causing subaerial land loss as well as subaqueous sediment transport. The goal of this study is to identify how wind, wind-driven waves, tides and currents interact in the Mississippi River Delta to transport water and sediment. Tripod-mounted optical and acoustic sensors were deployed in the Bottom Boundary Layer at 5 m and 10 m water depths in East Bay of the Mississippi River Delta to collect wave, tide, current, and sediment concentration data, across two deployment periods (winter and spring 2024) to examine the hydrodynamics and sediment dynamics. East Bay is a shallow and triangle-shaped interdistributary bay bounded by Southwest Pass and South Pass and is divided by a 10-km long E-W trending barrier island into two parts.
During the winter of 2024, episodic mixing occurs with cold, fresh river water into the lower water column at 5 m and 10 m water depths during the passage of cold fronts or strong easterly winds, coinciding with high sediment concentration peaking around 1-10 g L-1. During both the winter and the spring of 2024, strong easterly winds faster than 10 m s-1 caused significant wave heights larger than 1 m, which leads to increased sediment concentration due to resuspension. The E-W oriented barrier island in East Bay served as a morphological confinement to trap water and sediment in the shallow part of East Bay. The Turbulent Kinetic Energy (TKE) method calculated shear stresses of 1-6 Pa, with the shear stress trend closely resembling the trend of the significant wave heights. This new study serves as a benchmark for calculating the water and sediment budget in shallow Louisiana bays and estuaries with implications on how to harness natural processes like waves and tides to improve sediment retention in coastal restoration projects.
Date
7-10-2025
Recommended Citation
Reinhardt, Jacob E., "Hydrodynamics and sediment dynamics in East Bay of Mississippi River Delta, Louisiana, USA" (2025). LSU Master's Theses. 6187.
https://repository.lsu.edu/gradschool_theses/6187
Committee Chair
Xu, Kehui