...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Water >Bedload and Suspended Load Transport in the 140-km Reach Downstream of the Mississippi River Avulsion to the Atchafalaya River
【24h】

Bedload and Suspended Load Transport in the 140-km Reach Downstream of the Mississippi River Avulsion to the Atchafalaya River

机译：密西西比河阿伏拉河向阿恰法拉亚河下游140公里的下游河床和悬浮物运输

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Mississippi River Delta has been continuously losing land since the 1930s due to several factors, chief of which is the reduced sediment supply. A few recent studies have estimated individual components of short-term sediment transport, i.e., bedload and suspended load, separately for some locations along the Lowermost Mississippi River (LmMR, commonly considered as the last 500-km reach of the Mississippi River before entering the Gulf of Mexico). However, the combined effects of both components on the long-term sediment supply along the river reach are still unclear. One of the major obstacles here hindering our understanding is that it is difficult and impractical to accurately measure bedloads in large alluvial rivers, such as the Mississippi. In this study, we estimated bedloads of three medium grain sizes (D50 = 0.125, 0.25 and 0.5 mm) for three locations along the uppermost 140-km reach of the LmMR: Tarbert Landing (TBL) at river kilometer (rk) 493, St Francisville (St F) at rk 419, and Baton Rouge (BTR) at rk 367.5 during 2004–2015. We also estimated suspended loads at St F during 1978–2015 and at BTR during 2004–2015 in order to discern the interactive relationship between bedloads and suspended loads. We found gradually increasing bedloads for all the three medium grain sizes from TBL (83, 41.5 and 20.75 million tons (MT), respectively) to BTR (96, 48 and 24 MT). We also found that suspended loads at TBL (reported previously) were significantly higher than those at St F and BTR during corresponding overlapping periods. Bedloads increased almost linearly with suspended loads, river discharge and river stage at the upstream locations (TBL and St F); however, such a relationship was not evident downstream at BTR. The total sediment load (bedload + suspended sediment load) was substantially higher at TBL (931 MT), while lower and nearly equal at other two downstream locations (550 MT at St F and 544 MT at BTR) during 2004–2010 (the matching period of availability of both loads). These findings indicate that the uppermost 20–25 km LmMR reach (covering TBL) has potentially entrapped substantial suspended load over the last three to four decades, while bedload transport prevails in the lower reach (covering St F and BTR). We suggest that future sediment management in the river should seek engineering solutions for moving trapped coarse sediments downstream towards the coast for the Mississippi River Delta restoration
机译：自1930年代以来，由于多种因素，密西西比河三角洲一直在不断失去土地，其主要原因是泥沙供应减少。最近的一些研究估计了短期泥沙运移的各个组成部分，即沿密西西比河最下游（LmMR）的某些位置分别为河床负荷和悬浮负荷，通常被认为是进入密西西比河之前的最后500公里段。墨西哥湾）。然而，这两种成分对沿河长期沉积物供应的综合影响仍不清楚。这里阻碍我们理解的主要障碍之一是，在密西西比河等大型冲积河流中，准确测量床荷是困难且不切实际的。在这项研究中，我们估算了沿LmMR最高140公里到达的三个位置的三种中等粒度（D50 = 0.125、0.25和0.5 mm）的床荷：塔伯特着陆（TBL），位于河岸493公里（rk）在2004年至2015年期间，弗朗西斯维尔（St F）在rk 419，巴吞鲁日（BTR）在367.5 rk。我们还估算了1978–2015年的St F以及2004–2015年的BTR的悬浮载荷，以便辨别床载荷与悬浮载荷之间的相互作用关系。我们发现，从TBL（分别为83、41.5和20.75百万吨（MT））到BTR（96、48和24 MT）的所有三种中等粒度，床载量逐渐增加。我们还发现，在相应的重叠期间，TBL（先前报告）的悬挂载荷显着高于St F和BTR的悬挂载荷。床位负荷与上游位置（TBL和St F）的悬浮负荷，河水排放和河段几乎呈线性关系;但是，这种关系在BTR下游并不明显。在2004-2010年期间，TBL的总泥沙量（基岩量+悬浮的泥沙量）高得多（931 MT），而其他两个下游位置（St F 550 MT和BTR 544 MT）则较低且几乎相等（相匹配两种负载的可用期限）。这些发现表明，在过去的三到四十年中，最高的20-25 km LmMR距离（覆盖了TBL）可能会捕获大量的悬空负载，而下游的区域（覆盖了St F和BTR）则普遍存在床负载运输。我们建议，未来河流中的沉积物管理应寻求工程解决方案，以将捕获的粗糙沉积物向下游输送到密西西比河三角洲沿岸的海岸

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