Geomorphic changes upstream of beaver dams in Bridge Creek, an incised stream channel in the interior Columbia River basin, eastern Oregon
Geomorphic changes upstream of beaver dams in Bridge Creek, an incised stream channel in the interior Columbia River basin, eastern Oregon
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布里奇溪海狸坝上游的地貌变化，布里奇溪是俄勒冈州东部哥伦比亚河流域内切河道
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Chris E. Jordan
中科院分区：
文献类型：
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作者：
M. Pollock;T. Beechie;Chris E. Jordan
河道下切是世界上干旱内陆哥伦比亚河流域和其他半干旱地区的一种普遍现象，它通过从根本上改变自然生态、地貌和水文过程而使河流栖息地退化。我们研究了在哥伦比亚河流域内部的下切流海狸大坝后面的局部淤积的程度，以评估使用海狸，加拿大蓖麻，大坝恢复这些渠道的潜力，以及对河岸栖息地的淤积的影响。我们估计的淤积率背后的13海狸水坝1和6岁之间的桥溪，支流约翰戴河在东部俄勒冈州。垂直加积速率最初很快，高达0.47 m yr−1，因为挖沟充填，然后在第6年稳定到0.075 m yr−1，因为沉积物开始在相邻阶地上堆积。我们发现，0.5米以上的河道高程等高线大致符合新的河岸植被建立的程度。因此，我们将河狸坝上游0.5 m高程范围内的河段周边区域与没有水坝的邻近河段进行了比较。我们发现河狸坝上游河道0.5 m高程范围内的面积是河狸坝上游河道的5倍，这可能是因为沉积物堆积使河道淤积。我们的研究结果表明，恢复策略，鼓励河狸的河流切割可以迅速扩大河岸栖息地沿着切割流。版权所有© 2007约翰威利父子有限公司。
Channel incision is a widespread phenomenon throughout the dry interior Columbia River basin and other semi‐arid regions of the world, which degrades stream habitat by fundamentally altering natural ecological, geomorphological and hydrological processes. We examined the extent of localized aggradation behind beaver dams on an incised stream in the interior Columbia River basin to assess the potential for using beaver, Castor canadensis, dams to restore such channels, and the effect of the aggradation on riparian habitat. We estimated aggradation rates behind 13 beaver dams between 1 and 6 years old on Bridge Creek, a tributary to the John Day River in eastern Oregon. Vertical aggradation rates are initially rapid, as high as 0·47 m yr−1, as the entrenched channel fills, then level off to 0·075 m yr−1 by year six, as the sediment begins accumulating on adjacent terraces. We found that a 0·5 m elevation contour above the stream channel approximately coincided with the extent of new riparian vegetation establishment. Therefore, we compared the area surrounding reaches upstream of beaver dams that were within 0·5 m elevation of the stream channel with adjacent reaches where no dams existed. We found that there was five times more area within 0·5 m elevation of the channel upstream of beaver dams, presumably because sediment accumulation had aggraded the channel. Our results suggest that restoration strategies that encourage the recolonization of streams by beaver can rapidly expand riparian habitat along incised streams. Copyright © 2007 John Wiley & Sons, Ltd.