越来越多的供水商正在开发涉及重地下水的联合使用项目 在干旱年份进行开采，以提高供水可靠性。其中许多项目都涉及人工干预 在潮湿年份，补给以最大限度地增加蓄水层中储存的水量。最近的暴雨趋势 管理还包括最大限度地渗透。同时，河流和含水层之间的相互作用 正成为强烈的政治、法律和科学兴趣的焦点，加利福尼亚州就是明证 水资源控制委员会（Water Resources Control Board）约瑟夫·萨克斯（Joseph Sax）最近关于地下水法律分类的报告，以及 几个法庭案件。这些与水资源和水权相关的问题随着气候变化而不断升级 不断增长的人口和由此产生的日益增长的供水需求。 具有讽刺意味的是，有一种可能性是，天然地下水的补给和排放可能来自于相当长的一段水域 通过修建与河堤相关的深层灌浆防渗墙，主要河流正在减少。一 例如，穿过萨克拉门托县的美国下游河流。在加利福尼亚州附近 萨克拉门托大学（CSU）校园内，一堵泥浆墙被固定在60英尺深的粘土层上。渗透 通常会穿过河岸和河床，迁移到更深的供水含水层 通过非均质河流沉积物。泥浆壁减少了可供使用的沉积物体积 地下水/地表水相互作用，因此影响当地水文。这段较低的 美国河与许多其他河流相似，这些河流为地下水提供补给或接收地下水的排放 美国西部的盆地。 在CSU校园的美国河下游开始了对河流-含水层相互作用的评估， 包括堤防防渗墙对含水层补给的影响。几口地下水监测井 垂直于河流安装。该研究包括长期水位调查， 地球化学评估和堤坝附近的含水层测试。这项研究的结果将提供一个初步的结论 表明此类堤防项目是否会无意中影响地下水的水量平衡 盆

Increasing numbers of water purveyors are developing conjunctive use projects that involve heavy groundwater extraction during dry years to increase water supply reliability. Many of these projects involve artificial recharge to maximize the amount of water stored in the aquifer during wet years. A recent trend in stormwater management also includes maximizing infiltration. Concurrently, the interaction between streams and aquifers is becoming the focus of intense political, legal, and scientific interest, as evidenced by the California State Water Resources Control Board's recent report by Joseph Sax on the legal classification of groundwater, as well as several court cases. These water resources and water rights-related issues are continuing to escalate with the ever-increasing population and resultant growing demand on water supply. Ironically, there is the possibility that natural groundwater recharge and discharge from significant stretches of major rivers is being reduced by the construction of deep grout cut-off walls associated with river levees. One example is the Lower American River through Sacramento County. In the vicinity of the California State University Sacramento (CSUS) campus, a slurry wall is keyed to a clay layer at a depth of 60 feet. Infiltration would normally occur through the riverbanks and streambed and migrate to deeper water supply aquifers through the heterogeneous fluvial deposits. The slurry wall reduces the volume of sediment available for groundwater/surface water interaction and therefore affects the local hydrology. This stretch of the Lower American River is similar to many other rivers that provide recharge to, or receive discharge from, groundwater basins in the Western U.S. An evaluation of the stream-aquifer interaction was begun on the Lower American River at the CSUS campus, including the effect of the levee cut-off wall on recharge of the aquifer. Several groundwater monitoring wells have been installed perpendicular to the river. The study includes long-term water level surveys, geochemical evaluations, and aquifer testing adjacent to the levee. The study's results will provide an initial indication of whether such levee projects may be inadvertently affecting the water budget of the groundwater basin.