Semester of Graduation

Spring 2021

Degree

Master of Science (MS)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

The Lower Mississippi River Physical Model (LMRPM) is a distorted, movable bed model that simulates the hydraulics and sediment transport in the lower 195 miles of the Mississippi River. Carved into the model are both existing hydraulic structures, such as the Bonnet Carré Spillway, and proposed structures, such as the Mid-Barataria Sediment Diversion (MBSD). The MBSD will be the first sediment diversion built as part of Louisiana’s Coastal Master Plan, so incorporating the diversion in the LMRPM will be a useful tool to understanding how the diversion can impact the river hydraulics and bedload transport. The objective of this thesis was to perform preliminary tests on the model MBSD, which is incorporated as a sluice gate and conveyance channel, to understand the relationships controlling diverted discharge at different river discharges and future sea level conditions. The results of these preliminary tests were used to create operating procedures to model the expected performance of the prototype diversion. These operating procedures were tested using historical hydrographs. The results of these test showed that the operating procedures were able to achieve the target diverted discharges well, though improvements can be made to reduce the amount of error. The diverted discharge sediment fraction (δ) had values greater than or equal to 1, as well as greater variance in values, for higher river discharges. Detailed bed level measurements at the diversion did not show the expected short-term impact of erosion upstream and deposition downstream. Finally, dye studies showed that the presence of the operating diversion appears to cause significant increases in turbulence in the model river, especially for higher discharges.

Committee Chair

Willson, Clinton

DOI

10.31390/gradschool_theses.5290

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