Semester of Graduation

Fall 2017

Degree

Master of Science (MS)

Department

Department of Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

As coastal environments become more susceptible to land loss through accelerating sea level rise and subsidence, new restoration methods harnessing borrowed sediment are more valuable than ever. Mud-capped dredge pits (MCDPs) are a relatively new source of restoration-quality sediment that has only recently been utilized for beach and barrier island restorations in Louisiana. Because MCDPs have been in use for less than two decades in only a handful sites, little is understood about their evolution over decadal timescales. To improve our understanding of MCDPs after they are dredged, we have conducted a suite of geophysical surveys including bathymetry, sidescan sonar, CHIRP subbottom profilers, and magnetometry to monitor Peveto Channel dredge pit, the only infilled dredge pit to date offshore of Holly Beach, Louisiana.

Using newly collected and historical data, we are able to better evaluate key components of dredge pit evolution, such as infilling rate and pit margin erosion. Traditional models overestimate the rate at which sediment is deposited into the dredged pit. Additionally, due to the muddy overburden surrounding MCDPs, the pit walls are fairly stable over time, indicating that the walls experience little lateral movement over time. Using new results and knowledge gained from this study, we can better understand how to utilize MCDPs in the future, and better evaluate the current management of offshore sand resources and the regulations regarding setback buffer zones for pipelines and oil infrastructure.

Date

11-8-2017

Committee Chair

Xu, Kehui

DOI

10.31390/gradschool_theses.4335

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