Using <scp>LiDAR</scp>‐Based <scp>DEM</scp> Elevation Difference Calculations to Estimate Net Streambank Erosion in an Iowa River, <scp>USA</scp>

ABSTRACT Streambank erosion is an important source of sediment to river systems but is difficult to quantify at watershed scales. In this study, high‐resolution Light Detection and Ranging (LiDAR) measurements collected from 2009 and 2020 were used to quantify the difference in land surface elevation that occurred along the fourth and fifth‐order streams in Old Mans Creek watershed in southeast Iowa. Study objectives were to quantify the volume of streambank sediment erosion and deposition occurring along the river systems and compare net channel erosion to watershed sediment export. Results indicated that streambank erosion and deposition along the fourth and fifth‐order channels totaled nearly 720,000 m 3 and 148,000 m 3 , respectively, over the 11‐year study period. Five times more streambank erosion occurred than deposition, and the difference between the two totals (net sediment erosion) comprised 77% of the sediment export from the watershed. The contribution of streambank sediment to basin export, along with estimates of mean annual streambank recession derived from the analyses, were consistent with results reported in other studies of streambank erosion. The LiDAR differencing methodology was able to identify areas of both sediment erosion and deposition occurring in the stream channels and quantify the net difference, which is related to watershed‐scale sediment export.