Semester of Graduation

Spring 2021

Degree

Master of Science (MS)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

The Amite River Basin is a largely rural watershed spanning parts of four counties in southern Mississippi and seven parishes in southeast Louisiana, with basinwide imperviousness increasing from 0.82% in 1938 to 3.85% in 2016. The Basin has been the subject of significant research interest since catastrophic flooding in 2016 caused 13 deaths and widespread damages. Rapid development in recent decades has led to an expansion of impervious surfaces in Baton Rouge and surrounding areas, encroaching on floodplains and wetlands. At the basin scale, differences in flooding due to impervious cover changes were found to be somewhat limited, particularly along the main rivers and streams and for the larger, less frequent events. The Amite Basin is topographically flat with wide floodplains, high precipitation, and clayey soils. To model the effects of these historical changes, simulations were run in a HEC-HMS and coupled 1D/2D HEC-RAS model of the Amite River Basin for a variety of storms and land cover scenarios. The impacts of increasing surface imperviousness were more prominent at smaller spatial scales, where there has been significant development, and differences were more pronounced for smaller storms. Given the low impact of increasing impervious cover on flooding caused by the August 2016 storm and other large storms, flood mitigation efforts in the Amite River Basin and similarly flood-prone areas are likely best suited to large-scale projects like the Comite Diversion Canal and Darlington Dam, as well as smaller-scale interventions to manage the impacts caused by higher frequency, lower intensity storms that are often controlled by backwater conditions.

Committee Chair

Willson, Clinton S.

DOI

10.31390/gradschool_theses.5325

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