Date of Completion

2024

Thesis Type

College of Arts and Science Honors

Department

Geography and Geosciences

First Advisor

Rebecca Diehl

Second Advisor

Shelly Rayback

Keywords

bank erosion, sediment, Vermont, geomorphology

Abstract

Bank erosion is a dynamic process with large variability in rates across the landscape. Although prior studies have investigated streambank and channel erosion rates on cross-section to sub-watershed scales, there is limited understanding of regional streambank erosion in the Lake Champlain Basin (LCB). Consequently, the role of erosion in watershed sediment budgets and the contribution of bank derived sediment and associated nutrients to degraded water quality in Lake Champlain is not fully understood. The goal of our work is to obtain refined rates of erosion in the LCB and to understand the source of bank erosion variability. To achieve this goal, this project compiles studies on bank erosion rates in Vermont to develop a regional dataset of erosion rates and associated stream attributes in the LCB. We quantified bank erosion rates for five field sites from LiDAR and field-surveyed cross-sections. Data from six previous bank erosion studies, that contained one or more observations were identified, creating a dataset of mass erosion rates for 190 individual stream reaches, with drainage areas that span from 0.1 km2 to 2730.9 km2 in the LCB. The reaches were associated with Vermont ANR Stream Geomorphic Assessment data, populated with stream attributes, and analyzed to identify relationships between physical characteristics of the landscape and erosion rates. From our dataset, we found that erosion rates are highly variable, but that this variability can be described in part by drainage area, slope, incision ratio, and riparian vegetation cover. A better understanding of streambank erosion rates and important driving variables provides additional context for restoration practices and sediment deposition patterns on adjacent floodplains.

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