EXAMINING VARIABILITY IN STREAMBANK EROSION RATES IN THE LAKE CHAMPLAIN BASIN, VERMONT

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). This limits our understanding of 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. This project compiles studies on bank erosion rates in Vermont to develop a dataset of regional erosion rates and associated stream attributes in the LCB. The goal of our work is to obtain refined rates of erosion in the LCB and to understand the source of bank erosion variability. Data were extracted from six previous studies, including 175 individual stream reaches with drainage areas that span from 5km² to 2230km². Bank erosion data for an additional four field sites were added to the dataset, which were extracted from LiDAR-derived and RTK-GPS surveyed sections. In all we developed a dataset of mass erosion rates for 179 reaches throughout the LCB in Vermont. 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. Our dataset highlights that erosion rates are highly variable, but that this variability may be described by local land use, soil properties, and contributing drainage area. A better understanding of streambank erosion rates and important driving variables will provide additional context for sediment deposition patterns on adjacent floodplains.