...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Reconstruction of eroded and deposited sediment volumes of the embanked River Waal, the Netherlands, for the period AD 1631-present
【24h】

Reconstruction of eroded and deposited sediment volumes of the embanked River Waal, the Netherlands, for the period AD 1631-present

机译：重建公元1631年至今荷兰河床瓦尔河的侵蚀和沉积沉积物量

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

In the last few centuries humans have modified rivers, and rivers have responded with noticeable changes in sedimentary dynamics. The objective of this study is to assess these responses of the sedimentary dynamics. Therefore, we calculated a sediment budget for eroded and deposited sediment volumes in a ~12-km long floodplain section of the largest semi-natural embanked but still dynamic lower Rhine distributary, for ~50-years time slices between AD 1631 and present. This is the period during which embanked floodplains were formed by downstream migration of meander bends between confining dykes. Our sediment budget involves a detailed reconstruction of vertical and lateral accretion rates and erosion rates of floodplain sediment. To do so, we developed a series of historical geomorphological maps, and lithogenetic cross-sections. Based on the maps and cross-sections, we divided the floodplain into building blocks representing channel bed and overbank sediment bodies. Chronostratigraphy within the blocks was estimated by interpretation of heavy metal profiles and from optically stimulated luminescence (OSL) dating results. Sediment budgets were hence calculated as a change of volume of each building block between time steps. The amount of lateral accretion initially increased, as a result of island and sand bar formation following embankment. From the eighteenth century onwards, there was a decrease of lateral processes in time, which is a result of straightening of the river by human activities, and a reduction of water and sediment supply due to the construction of a new upstream bifurcation. With straightening of the river, the floodplain area grew. Artificial fixation of the channel banks after AD 1872 prevented lateral activity. From then on, overbank deposition became the main process, leading to a continuous increase of floodplain elevation, and inherent decrease of flooding frequency and sediment accumulation rate.
机译：在过去的几个世纪中，人类对河流进行了改造，河流的沉积动力学发生了显着变化。这项研究的目的是评估沉积动力学的这些响应。因此，我们计算了最大的半天然堤岸但仍充满活力的莱茵河下游分流区约12公里长的洪泛区剖面中侵蚀和沉积的沉积物量的沉积物预算，时间范围为公元1631年至今，历时约50年。在这段时期内，围堤之间蜿蜒曲折的下游迁移形成了堤岸泛滥平原。我们的沉积物预算包括详细重建洪泛区沉积物的垂直和横向吸积率和侵蚀率。为此，我们开发了一系列历史地貌图和岩成岩横截面。根据这些地图和横截面，我们将洪泛区分为代表河床和河床沉积物的构造块。通过解释重金属剖面和光学激发发光（OSL）测年结果估算了地块内的年代地层。因此，沉积物预算被计算为每个构建块在时间步长之间的变化。由于路堤后形成岛状和沙洲，横向吸积量开始增加。从18世纪开始，由于人类活动使河道变直而导致横向过程的时间减少，并且由于修建了新的上游分岔而减少了水和沉积物的供应。随着河道的拉直，洪泛区面积增加。公元1872年后人工固定河道堤防了横向活动。从那时起，滩涂沉积成为主要过程，导致洪泛区海拔高度不断增加，洪水频率和沉积物堆积速率固有地降低。

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