Date of Award
12-2025
Degree Type
Thesis
Degree Name
M.S.
Degree Program
Earth & Environmental Science
Department
Earth and Environmental Sciences
Major Professor
Madeline Foster-Martinez
Second Advisor
Robert Mahon
Third Advisor
Chris Esposito
Abstract
Deltaic wetlands rely on vegetation to retain sediment and build land, yet the effects of seasonal vegetation changes on the land-building process remain poorly understood. This study measured sediment capture rates for Colocasia esculenta (wild taro), an invasive species in Louisiana’s deltaic marshes, using a 22-meter recirculating flume. We measured suspended sediment concentration (SSC) over time using optical turbidity sensors and compared rates of SSC reduction under four controlled flow conditions and three patch conditions: bare ground, live vegetation, and senescent vegetation. Each experiment ran for one hour. Finely ground walnut shells were used for the suspended sediment. C. esculenta was collected from Bayou St. John, Louisiana, and maintained in a greenhouse. To induce senescence, the vegetation was kept in a dark climate-controlled room for two weeks. Images and measurements of vegetation characteristics were taken prior to each experimental run. Despite a 20 percent decline in stem density and 30 percent loss in stem height, senescent plants retained sediment as effectively as live ones. Calculated retention efficiency was slightly higher in senescent vegetation, possibly due to biofilm or increased surface adhesion. Faster flows enhanced sediment capture across all treatments. These findings show that senescent vegetation contributes meaningfully to sediment retention, enabling restoration strategies that account for seasonal vegetation cycles.
Recommended Citation
Davidson, Donald, "Plants, Sediment, & Water: How Seasonal Changes Affect Deltaic Land-building" (2025). University of New Orleans Theses and Dissertations. 3307.
https://scholarworks.uno.edu/td/3307
Rights
The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.