• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Geomorphology >The impacts of the Three Gorges Dam upon dynamic adjustment mode alterations in the Jingjiang reach of the Yangtze River, China
【24h】

The impacts of the Three Gorges Dam upon dynamic adjustment mode alterations in the Jingjiang reach of the Yangtze River, China

机译：三峡大坝对长江靖江段动态调整方式变化的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Dam operation profoundly modifies downstream flow-sediment regimes, resulting in a variety of geomorphologic responses, without uniform laws. The Jingjiang reach of the middle Yangtze River has undergone significant adjustment mode alterations, with intensive channel erosion and major adjustment area changing from the bankfull channel to the medium flow channel at the time boundary of the Three Gorges Dam (TGD) impoundment. While these changes have received some attention, little work has been undertaken to reveal the reason. In this study, based on 172 cross sections measured in the post-flood period from 2003 to 2015, different river patterns, longitude and reach-averaged channel dimensions were assessed to reflect the channel adjustment characteristics of the Jingjiang reach. An index has been proposed to measure the cumulative water transport capacity of each discharge interval and to assess the relationship with reach-scale medium flow channel dimensions. The results indicate that the channel adjustment changes are directly driven by the alterations of flow duration and sediment transport capacity. With the deficiency of floods, medium flow channels respond quite well to small and medium discharges of under approximately 16,500 m3/s. A discharge of 16,500 m3/s which can be regarded as a critical threshold, corresponds to the average top levels of braided and meandering channel bars, which are of morphological significance in constraining the passing flow in the medium flow channel. Small and medium discharges under the critical threshold associate with relatively larger reductions in sediment loads and hold increased geomorphic impacts (QmJP), eventually resulting in adjustment mode alterations. The results present herein for the Jingjiang reach of the Yangtze River can provide a better understanding of dam operation and the corresponding impacts on downstream channel morphology.
机译：大坝的运行深刻地改变了下游的水流沉降状态，导致了各种地貌响应，而没有统一的规律。长江中游的靖江河段经历了重大的调整方式变化，在三峡大坝（TGD）蓄水时限处，河道密集侵蚀，主要调整区域由河岸河道变为中流河道。尽管这些更改引起了一定的关注，但几乎没有任何工作可以揭示原因。在这项研究中，基于2003年至2015年洪灾后测量的172个断面，评估了不同的河流类型，经度和平均河道尺寸，以反映靖江河段的河道调整特征。已经提出了一种指标，用于测量每个排放间隔的累积水输送能力，并评估与到达规模的介质流道尺寸的关系。结果表明，水流持续时间和泥沙输送能力的变化直接驱动着河道的调整变化。由于洪水不足，中等流量通道对大约16,500 m3 / s以下的中小型排放反应良好。 16,500 m3 / s的放电量（可以视为临界阈值）对应于编织和曲折通道条的平均最高水平，这对限制介质通道中的通过流量具有形态学意义。在临界阈值以下的中小流量排放量会相对较大地减少泥沙量，并增加地貌影响（QmJP），最终导致调整模式发生变化。本文针对长江靖江段的结果可以更好地理解大坝的运行及其对下游河道形态的影响。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号