Streambank erosion processes influence the amount of soil material contributed to rivers and sedimentation rates in receiving reservoirs. However, the amount of data on bank erosion rates is limited both in range and extent affecting planning for mitigation and watershed management. Dendrogeomorphology is used to determine the date of wood anatomy changes in annual growth increments of roots exposed by erosion of stream banks that when coupled with measurement of the distance of roots to the channel side can be used to calculate the bank retreat rate. Erosion rates derived from dendrogeomorphology are important because these provide erosion data over longer time scales (decades). Here, we use this method to quantify erosion for three different sized watersheds (4 to 3781 km2) located in the water‐scarce southern U.S. prairies that are heavily reliant on surface water and reservoir storage. From 49 roots from the two smaller drainages, erosion ranged from 1.5 to 25.4. For 19 roots collected from the larger subbasin erosion rates were larger ranging from 7.4 to 325.0 cm/years with the larger values and variance associated with two high‐flow events that occurred a year before sampling. We also found differences in straight and meandering portions of the streams where the distance to bank was strongly and positively correlated with the years since root exposure in straight sections. In contrast, meandering bends also showed a positive but low correlation for root exposure date and distance collected. We attribute this difference to erosional processes (i.e., scour and mass wasting) occurring at these channel locations. When compared with other erosion studies across the southern U.S. prairie, our values were similar in magnitude but with low correlation to drainage area indicating site specificity of erosion mechanisms, and watershed landcover influence for different drainages, despite being in the same ecological region.

中文翻译：

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美国南部草原溪流树状地貌的河岸侵蚀和侵蚀过程

河岸侵蚀过程影响河流的土壤物质数量和接收水库的沉积率。然而，河岸侵蚀率的数据量在影响缓解和流域管理规划的范围和程度上都有限。树状地貌学用于确定因河岸侵蚀而暴露的根系的年生长增量的木材解剖变化的日期，结合测量根系到河道一侧的距离，可用于计算河岸退缩率。由树状地貌得出的侵蚀率很重要，因为它们提供了较长时间尺度（数十年）的侵蚀数据。在这里，我们使用这种方法来量化三个不同大小流域（4 至 3781 公里）的侵蚀2）位于缺水的美国南部大草原，严重依赖地表水和水库蓄水。两个较小排水系统的 49 个树根的侵蚀程度从 1.5 到 25.4 不等。对于从较大子流域收集的 19 个根，侵蚀率较大，范围为 7.4 至 325.0 厘米/年，较大的值和方差与采样前一年发生的两次高流量事件相关。我们还发现河流的笔直部分和蜿蜒部分存在差异，其中到河岸的距离与笔直部分根部暴露后的年份呈强烈正相关。相比之下，蜿蜒的弯曲也显示出与根部暴露日期和收集的距离呈正相关但较低的相关性。我们将这种差异归因于这些河道位置发生的侵蚀过程（即冲刷和质量浪费）。与美国南部草原的其他侵蚀研究相比，我们的值在幅度上相似，但与流域面积的相关性较低，表明侵蚀机制的地点特异性以及不同流域的流域土地覆盖影响，尽管位于同一生态区域。