The 2010 dam breach and consequent anomalous flood event on the Cedar River in Nebraska, USA provided an opportunity to study the following objectives: (1) evaluate the impact of an extreme flood event on streambank retreat along a 45 km stretch relative to the average annual retreat; (2) quantify the changes in streambank retreat for each km segment downstream of the breach; and (3) examine the influence of riparian vegetation and radius of curvature on meander bank erosion rate. During the hydrologic event, discharge peaked at nearly three times greater than the next highest recorded rate and equated to a return period of 2,000 years. Aerial images and ArcGIS were utilized to calculate the average annual streambank retreat for each year during the preflood (2006–2010), flood (2010), and postflood (2010–2016) periods. The 2010 flood period had a significantly higher average annual streambank retreat of 2,820 m²/km/yr than the preflood and postflood periods, which, respectively, measured 576 and 384 m²/km/yr. From 2006 to 2016, 29% of all streambank erosion was from this one extreme flood event, thus demonstrating the impact that one extreme flood event can have on streambank retreat and the geomorphology of a stream system.

中文翻译：

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极端洪水事件对河岸撤退的影响：美国内布拉斯加州锡达河

2010年美国内布拉斯加雪松河大坝溃决及随之而来的异常洪水事件为研究以下目标提供了机会：（1）评估极端洪水事件对相对于年均45 km延伸段河岸撤退的影响撤退; （2）量化突破口下游每公里河段退溪的变化；（3）研究河岸植被和曲率半径对河岸侵蚀速率的影响。在水文事件期间，排放量的峰值比下一个最高记录速率高近三倍，相当于2000年的恢复期。利用航拍图像和ArcGIS计算洪水前（2006-2010年），洪水（2010年）和洪水后（2010-2016年）期间每年的年平均河岸撤退量。² /千米/年的比preflood和postflood周期，它们分别测量576和384米² / km的/年。从2006年到2016年，所有河岸侵蚀中有29％来自这一极端洪水事件，从而证明了一次极端洪水事件可能对河岸撤退和河流系统的地貌产生的影响。