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.

中文翻译：

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量化爱荷华州侵蚀河岸的程度

河岸侵蚀是河流沉积物的主要来源，重要的是要找到流域中发生严重侵蚀河岸的地点。在这项研究中，使用高分辨率光探测和测距 (LiDAR) 高程数据进行了一种绘制区域尺度侵蚀河岸图的新方法。通过校准 LiDAR 衍生数据的现场测绘研究，估计了爱荷华州发现的三至六级溪流和河流中严重侵蚀河岸的程度。研究结果表明，超过 35,200 公里的河岸可能受到严重侵蚀，约占所有三至六阶河岸的 41%。整个州的河岸侵蚀程度并不统一，爱荷华州西部和南部丘陵地带发生的侵蚀更多，而爱荷华州北部较平坦且最近被冰川覆盖。河岸侵蚀与更大的河岸高度有关，并且在较大的五级和六级河流中更为普遍（占河流总长度的百分比）。总体而言，尽管与 LiDAR 数据集的收集和外推相关的研究存在局限性，但研究结果为爱荷华州河岸侵蚀问题的严重程度提供了新证据，并可能适用于美国中西部类似的冰川地区。