Quantifying the Extent of Eroding Streambanks in Iowa

Streambank erosion is a major source of sediment to rivers and it is important to find locations where severely eroding streambanks are occurring in watersheds. In this study, a new approach to mapping eroding streambanks at a regional scale was conducted using high‐resolution Light Detection and Ranging (LiDAR) elevation data. By calibrating field mapping studies to LiDAR derivative data, the extent of severely eroding streambanks in third‐ to sixth‐order streams and rivers found in Iowa was estimated. Study results suggest that over 35,200 km of streambanks may be severely eroding, or approximately 41% of all third‐ to sixth‐order streambanks. The extent of streambank erosion was not uniform across the state with more erosion occurring in hillier western and southern Iowa compared to flatter and more recently glaciated northern Iowa. Streambank erosion was related to greater bank heights and was more prevalent (as a percent of the total stream length) in larger fifth‐ and sixth‐order rivers. Overall, despite limitations in the study related to the collection and extrapolation of the LiDAR dataset, study results provide new evidence for the magnitude of the streambank erosion problem in Iowa and likely apply to similarly glaciated regions of the United States Midwest. Research Impact Statement: The purpose of the Research Impact Statement (RIS) is to highlight one major insight or finding of broad interest to researchers, policy makers, practitioners, and the general public and should emphasize your paper’s practical or policy significance. This information may be used to promote the paper on social media sites (e.g., Twitter, LinkedIn) and therefore, to the extent possible, should be jargon free. The RIS is limited to 200 characters including spaces and punctuation.