Paleohydrologic Controls on Alluvial Deposition: A Process-Simulation Approach to Reconstruct Aquifer Heterogeneity

0207177 gorelick。物理过程模拟可以作为一种方法来帮助重建用于供水的含水层中沉积物的空间格局。沉积演化是用一种基于大规模数学的过程模拟模型来模拟的，该模型描述了几十万年来发生的水文、沉积和构造事件。我们感兴趣的具体过程是大洪水、沉积、侵蚀、压实、沉降、海平面变化和区域尺度的断层运动。该产品是研究含水层地层及其与古水文和构造条件演化联系的定量工具。该工具可用于水文地质调查，其中相对流道和流障的大规模格局是重要的。该油田的应用区域位于加州北部的圣克拉拉山谷，面积约为240平方米。地下水提供了圣克拉拉山谷约一半的公共供水，但由于粘土压实，抽水造成了严重的地面沉降问题。在大多数地区，人们对含水层非均质性和约束层几何形状对地下水流动和地面沉降的控制知之甚少。该山谷位于海沃德-卡拉维拉斯和圣安德烈亚斯断层系统的东部和西部的地块内的一个构造凹陷中。分别。多含水层系统由合并的冲积扇组成，这些冲积扇与过去60万年形成的河口沉积物相互交错。沉积过程模拟模型的结果将与覆盖河谷某些部分的地质和水文地质数据进行比较。目的是利用该模型来解释各种过去的水文和地质过程在冲积-海湾含水层结构发展中所起的作用。

0207177Gorelick.Physical process simulation can be used as a too] to help reconstruct the spatial pattern of sediments comprising aquifers used for water supply. Sedimentary evolution is simulated using a process-imitating model, based on large-scale mathematics, that describes hydrologic, sedimentary, and tectonic events which have occurred over hundreds of thousands of years. The specific processes of interest are major floods, sedimentation, erosion, compaction, subsidence, sea-level variation, and regional-scale fault motion. The product is a quantitative too] to study aquifer stratigraphy and its evolutionary link to paleohydrology and tectonic conditions. This tool can be used in hydrogeologic investigations where the large-scale pattern of relative flow paths and flow barriers is important.The field area for application is the Santa Clara Valley in northern California, which is Approximately 240 mi2 Groundwater provides approximately half of the public water supply in Santa Clara Valley, yet pumping has caused a serious problem of land subsidence due to clay compaction. In most areas, the controls on groundwater flow and land subsidence imposed by aquifer heterogeneity and confining bed geometry are poorly understood. The Valley occupies a structural depression within a block bounded on the cast and west by the Hayward-Calaveras and San Andreas Fault systems. Respectively. The multiaquifer system consists of coalescing alluvial fans interfingered with estuarine deposits that have been formed over the past 600,000 years. The sedimentary process simulation model results will be compared to geologic and hydrogeologic data covering certain portions of the Valley. The goal is to use the model to interpret the roles played by various past hydrologic and geologic processes on the development of alluvial-bay aquifer architecture.