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Control and Modeling of Seawater Intrusion for Conservation of Fresh Groundwater in Coastal Aquifers

海水入侵控制和模拟以保护沿海含水层地下水

基本信息

批准号：
19580283
负责人：
MOMII Kazuro
金额：
$ 3万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2007
资助国家：
日本
起止时间：
2007 至 2009
项目状态：
已结题

项目摘要

Seawater intrusion is often a major constraint to optimal use of fresh groundwater from coastal aquifers. Excessive groundwater extraction to meet growing demands from an increasing coastal population and the expected rise in mean sea level from global warming will cause seawater to encroach farther inland and threaten the available groundwater supply. In this study, laboratory experiments and numerical analysis were performed to determine the effectiveness of physical barriers and artificial recharge methods to control the seawater intrusion in coastal aquifers. The physical barriers examined were subsurface dams and partially penetrating flow barriers, while the artificial recharge methods included recharge ponds and recharge wells. In the study of subsurface dams, experimental and numerical results show that the residual saltwater trapped in storage areas by cutoff walls is completely flushed out by the freshwater flow from inland.In the study of subsurface flow barriers, we found that saltwater repulsion was linearly related to horizontal barrier location and a third-order polynomial function of penetration depth. For a particular freshwater discharge, this relationship can be used to determine the theoretical saltwater repulsion achieved by subsurface flow barriers of specific depth and location relative to the toe of the intruding saltwater wedge.In the artificial recharge studies, results show that more effective saltwater repulsion can be achieved when recharge is applied near the saltwater toe. Recharge becomes less effective when applied farther and higher from the toe. These findings imply that, for the same recharge rate, recharge wells are more effective than recharge ponds in repulsing saltwater intrusion.

海水入侵往往是优化利用沿海含水层淡水地下水的主要限制因素。为满足沿海人口不断增加的需求而过度抽取地下水，以及全球变暖导致平均海平面预计上升，将导致海水进一步侵入内陆，威胁现有地下水供应。通过室内实验和数值分析，研究了物理屏障和人工回灌方法控制海水入侵的有效性。检查的物理障碍物是地下水坝和部分穿透流动障碍物，而人工补给方法包括补给池和补给威尔斯。在地下坝的研究中，试验和数值计算结果表明，防渗墙截留在蓄水区的残余盐水会被来自内陆的淡水流完全冲掉;在地下水流屏障的研究中，我们发现盐水排斥力与水平屏障位置和渗透深度的三次多项式函数呈线性关系。对于一个特定的淡水排放量，这种关系可以用来确定理论上的盐水排斥所实现的地下水流障碍物的特定深度和位置相对于脚趾的侵入盐水wedge.In人工补给研究，结果表明，更有效的盐水排斥时，可以实现附近的盐水脚趾的补给。充电变得不太有效时，适用于更远，更高的脚趾。这些发现意味着，对于相同的回灌率，回灌威尔斯是更有效的比回灌池在击退盐水入侵。