CAREER: Integrated Stratigraphic and Hydrogeologic Aquifer Analysis: Toward Improved Multi-scale Characterization of Alluvial Aquifer Systems

准确地模拟和预测地下水系统中污染物的迁移和去向需要我们提供详细的含水层特征。最近，PI和他的同事开发了一种新的层序地层学方法来描述水相分布，用于河流为主的冲积扇系统上的地下水模型，从而整合了地质和水文评估。这项工作产生了几个问题，指导了这项拟议的研究项目，包括：1)在其他冲积扇系统中是否存在层序和体系域；2)在粘土丰富的成熟古土壤的边界下，是否存在层序，将地下水流动划分为水地层单元；以及3)层序地层学能否为其他冲积扇系统改进地下水模拟提供一个框架。通过在劳伦斯利弗莫尔国家实验室(LLNL)进行的沉积学、古地质学和水文地质分析，我们打算检验由这些问题形成的假设。LLNL现场的初步工作表明，成熟的古土壤可能束缚了水文地层单位，从而表明存在古土壤界限层序，层序几何结构可能强烈影响含水层水动力学。通过这项工作，我们将(1)描述以前收集的大约6000米的岩心，(2)评估古土壤的形态和化学，(3)对这个复杂的含水层系统内的地层、多尺度相分布、地下水流动和污染物运移进行建模，以及(4)评估数据价值，以评估在类似地质环境下未来工作的最低数据要求。这些模型将根据含水层测试和污染物浓度数据进行测试。这项工作的一个主要目标是让许多学生研究人员参与这个项目，因此几个学生将直接参与日常研究活动。此外，这项研究的各个方面将被纳入课堂活动，在课堂活动中，含水层和石油储集层评估课程的学生将分析岩心，在一个小地点构建三维地层框架，并对该地点的非均质性进行建模。这不仅会让学生接触到研究项目，还会为模拟结果的不确定性评估提供地层特征的多重“实现”。

0133666WeissmannAccurate modeling and prediction of contaminant transport and fate in groundwater systems requires that we produce detailed aquifer characterizations. Recently, the PI and colleagues developed a novel sequence stratigraphic approach to characterizing hydrofacies distributions for use in groundwater models on a stream-dominated alluvial fan system, thus integrating geological and hydrological assessment. Several questions resulted from this work that guides this proposed research project, including: 1) do sequences and systems tracts exist in other alluvial fan systems; 2) do sequences, bounded by clay-rich mature paleosols, compartmentalize groundwater flow into hydrostratigraphic units; and 3) can sequence stratigraphy provide a framework for improved groundwater modeling on other alluvial fan systems. Through sedimentologic, paleopedologic, and hydrogeologic analysis at the Lawrence Livermore National Laboratory (LLNL), a site with extensive core, geophysical well log, and 3D hydrologic test data, we intend to test hypotheses formed from these questions. Preliminary work at the LLNL site indicates that mature paleosols may bound hydrostratigraphic units, thus indicating that paleosol bounded sequences exist and that sequence geometry may strongly influence aquifer hydrodynamics. Through this work, we will (1) describe about 6000 meters of previously collected core, (2) assess paleosol morphology and chemistry, (3) model the stratigraphy, multi-scale facies distributions, groundwater flow, and contaminant transport within this complex aquifer system, and (4) assess data value to evaluate minimum data requirements for future work in similar geologic settings. These models will be tested against aquifer test and contaminant concentration data. A major objective of this work is to involve many student researchers in this project, thus several students will be directly involved in daily research activities. Additionally, aspects of this research will be incorporated into classroom activities, where students in an aquifer and petroleum reservoir assessment course will analyze core, construct the 3-D stratigraphic framework at a small site, and model the heterogeneity at the site. This will not only expose students to the research project, but will provide multiple 'realizations' of the stratigraphic character for uncertainty assessment of the modeling results.