River systems in the mountain western USA have been shaped by the presence of beavers for millennia. However, beavers have been extirpated from the landscape in many places, leading to excessive stream incision and streambank erosion. One common strategy to mitigate this issue is to deploy beaver dam analogue (BDAs) as a stream restoration technique. Although BDAs are intended to reduce erosion and stream incision, few studies directly document the impact of BDAs on stream channel geomorphology. This study, therefore, assesses how a complex of five BDAs along a 150 m long stream reach in Red Canyon Ranch near Lander, WY impacts stream bank erosion and deposition and channel evolution over a 1-year period post-installation. Relative to control locations not impacted by BDAs, the BDA reach showed greater spatial heterogeneity in erosion and deposition patterns than control locations, as well as less overall erosion. However, each BDA had unique effects on channel morphology. Large amounts of deposition were found at the most upstream BDA remaining after the first year at both inner and outer meander locations. High flow events created breaches that likely produced significant stream bank erosion observed immediately downstream of the BDA complex. From a design standpoint, the only BDAs that remained after a year were those built around fence posts inserted into the stream bed with a percussion fence post driver. Overall, our short-term data indicate that BDAs can be successfully used as a stream restoration practice to reduce stream bank erosion and increase channel geomorphological heterogeneity.

中文翻译：

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海狸坝类似物对美国西部半干旱景观河岸侵蚀和沉积的短期影响

几千年来，美国西部山区的河流系统一直被海狸的存在所塑造。然而，海狸已在许多地方从景观中灭绝，导致河流过度切割和河岸侵蚀。缓解此问题的一种常见策略是部署海狸坝模拟 (BDAs) 作为一种流恢复技术。尽管 BDAs 旨在减少侵蚀和河流切口，但很少有研究直接记录 BDAs 对河道地貌的影响。因此，本研究评估了沿 150 m 长的河流到达怀俄明州兰德附近红峡谷牧场的五个 BDA 的综合体如何在安装后的 1 年期间影响河岸侵蚀和沉积以及河道演变。相对于不受 BDAs 影响的控制位置，BDA 河段在侵蚀和沉积模式上显示出比对照位置更大的空间异质性，以及更少的整体侵蚀。然而，每个 BDA 对通道形态都有独特的影响。在第一年后剩余的最上游 BDA 处发现了大量沉积物，在内部和外部曲流位置。在 BDA 综合体的下游立即观察到，高流量事件造成了可能导致严重的河岸侵蚀的裂缝。从设计的角度来看，一年后唯一保留的 BDAs 是围绕栅栏柱建造的，这些栅栏柱通过冲击栅栏柱驱动器插入河床。总体而言，我们的短期数据表明，BDAs 可以成功地用作河流恢复实践，以减少河岸侵蚀并增加河道地貌异质性。