Response and Recovery of a Piedmont Watershed From Tropical Storm Agnes, June 1972
Response and Recovery of a Piedmont Watershed From Tropical Storm Agnes, June 1972
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1972 年 6 月热带风暴艾格尼丝对皮埃蒙特流域的响应和恢复
DOI：
10.1029/wr010i001p00106
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发表时间：
1974
影响因子：
5.4
通讯作者：
J. Costa
中科院分区：
文献类型：
--
作者：
J. Costa
热带风暴艾格尼丝在一个皮埃蒙特分水岭引发洪水，重现期远大于100年：从60 mi2到633 cfs/mi2。洪泛平原上的沉积物很少，可以绘制成沙子和砾石以及沙子。沉积发生在支流与主河道汇合的地方，穿过蜿蜒的弯道，以及在道路和桥梁等山谷限制之下。尽管降雨量和洪水量很大，但盆地内没有发生边坡失稳。对分水岭的唯一修改是在主要水道沿着的低地观察到的。河道拓宽是最引人注目的变化。洪水后1年内，河道横截面沿着恢复到Agnes前的尺寸。河道的弯曲河段比直线河段恢复得更快。艾格尼丝洪水几乎是有史以来最大的报告从一个皮埃蒙特流域的这种规模。皮埃蒙特的大洪水显然在塑造景观方面起着次要作用，而蓝岭/山谷和山脊和阿巴拉契亚高原省的大洪水以及随之而来的边坡破坏是非常活跃的景观美化因素。
Tropical storm Agnes generated flooding with a recurrence interval much greater than 100 years in a Piedmont watershed: 633 cfs/mi2 from 60 mi2. Deposits on floodplains were scarce and could be mapped as sand and gravel and as sand. Deposition occurred where tributaries joined the main channel, across meander bends, and below valley constrictions such as roads and bridges. Despite the magnitude of the rainfall and flooding there were no slope failures in the basin. The only modifications to the watershed were observed in the lowlands along the main channels. Channel widening was the most spectacular modification. Within 1 year of the flood, channel cross sections were well along recovery toward pre-Agnes dimensions. Meandering reaches of the channel recover faster than straight reaches. The Agnes flood is nearly the largest ever reported from a Piedmont watershed of this size. Large floods in the Piedmont apparently play a minor role in shaping the landscape, whereas large floods in the Blue Ridge/Valley and Ridge and Appalachian Plateau provinces, and consequent slope failure, are very active landscaping agents.