Observations from ground‐penetrating radar, sediment cores, elevation surveys and aerial imagery are used to understand the development of the Elwha River delta in north‐western Washington, USA, which prograded as a result of two dam removals in late 2011. Swash‐bar, foreshore and swale depositional elements are recognized within ground‐penetrating radar profiles and sediment cores. A model for the growth and development of small mountainous river wave‐dominated deltas is proposed based on observation of both the fluvial and deltaic settings. If enough sediment is available in the fluvial system, mouth‐bars form after higher than average river discharge events, creating a large platform seaward of the subaqueous delta plain. Swash‐bars form concurrently or within a month of mouth‐bar deposition as a result of wave action. Fair‐weather waves drive swash‐bar migration landward and in the direction of littoral drift. The signature of swash‐bar welding to the shoreline is landward‐dipping reflections, as a result of overwash processes and slipface migration. However, most swash‐bars are eroded by the river mouth, as only 10 of the 37 swash‐bars that formed between August 2011 and July 2016 survived within the Elwha River delta. The swash‐bars that do survive either amalgamate onto the shoreline or an earlier deposited swash‐bar, forming a single larger barrier at the delta front. In asymmetrical deltas, the signature of swash‐bar welding is more likely to be preserved on the downdrift side of the delta, where formation is more likely and accommodation behind newer swash‐bars preserves older deposits. On small mountainous river deltas, welded swash‐bars may be more indicative of a large sediment pulse to the system, rather than large hydrological events.

中文翻译：

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山区河流为食的波浪主导型三角洲增长与发展的模型：华盛顿Elwha河三角洲的见解

通过探地雷达，沉积物岩心，高程测量和航空影像获得的观测资料，了解了美国西北华盛顿的Elwha河三角洲的发展，该地区的发展是由于2011年末两次拆除大坝而导致的。 ，可以在穿透地面的雷达剖面和沉积物核心中识别出前滨和sw沉积元素。基于对河流和三角洲环境的观测，提出了一个以山区河流波为主的三角洲的增长和发展模型。如果河流系统中有足够的沉积物，则在高于平均水平的河流排泄事件之后形成口状条带，从而在水下三角洲平原上形成了一个大的平台向海。由于波浪作用，斜杠同时形成或在口条沉积一个月之内形成。晴朗的天气波推动斜杆向内移动并向沿海漂移的方向移动。由于过度冲洗过程和滑移面迁移，斜杠焊接到海岸线的特征是向地倾斜的反射。但是，大多数斜盘都被河口侵蚀了，因为2011年8月至2016年7月期间形成的37个斜盘中只有10个幸存于Elwha河三角洲内。斜盘确实可以生存下来，要么合并到海岸线上，要么幸存下来，但在三角洲前缘形成了一个较大的屏障。在非对称三角洲中，斜盘焊的签名更有可能保留在三角洲的下漂侧，在那里形成的可能性更大，并且在较新的斜盘后面的位置可保留较旧的沉积物。在山区多山的三角洲上，