GIS-Based Streambank Video Mapping to Determine Erosion Susceptible Areas

According to the U.S. Environmental Protection Agency, excess sediment is a significant cause of water quality impairment for rivers (USEPA, 2009). Therefore, determining the areas of river where streambank erosion is the highest should provide valuable information. Considering the amount of funds being spent on river restoration and storm flow retention, there needs to be a more efficient method to document annual conditions, on a watershed scale. Traditional streambank survey methods are limited in total characterized area, time consuming, environmentally intrusive, and expensive. This project describes the development of a Bank Erosion Susceptibility Index (BESI) to map landscape scale, streambank erosion susceptibility. The Streambank Video Mapping System (SVMS) equipped kayak provides georeferenced video footage correlated with Global Positioning Systems (GPS), for Geographic Information Systems (GIS) mapping applications. BESI was then applied to the video with erosion susceptibility scores being displayed within ArcGIS. Parameters being assessed while watching georeferenced video include bank angle, bank height to bankfull ratio, surface protection, and riparian diversity. A 7.7 km reach of the New River (TN) was mapped and determined to be 78% low, 21% moderate, and only 1% high scores of erosion susceptibility. A 7.6 km reach of Beaver Creek was mapped with 81% low, 18% moderate, and 1% high scores of erosion susceptibility. Physical field measurements were compared to video assessment showing an average of -1.4 percent error at 38 sites. Additional analysis showed a 3.5 BESI score standard error value, relating to viewer subjectivity between five people applying the BESI. Through this method, field time, cost, and environmental impact will all be reduced, with the most erosion-susceptible areas being highlighted for further documentation or restoration efforts.