RUI: Predicting Transport Through Heterogeneous Facies Assemblages: Geostatistical Anatomy of Buried-Valley Aquifiers, II

RUI：通过非均质相组合预测输运：埋谷含水层的地统计解剖学，II

• 批准号: 9628299
• 负责人: Robert Ritzi
• 金额: $ 6.61万
• 依托单位: Wright State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9628299&HistoricalAwards=false
• 关键词: RUI; Predicting; Transport; Through; Heterogeneous

9628299 Ritzi Contaminant problems have created the need to understand how hydraulic conductivity (K) is distributed in aquifer systems. Extreme-value pathways exert a dominant physical control on contaminant transport, and thus the boundary between high-K and low-K materials (hydrofacies) must be quantified. Although the exact geometry of the hydrofacies can only be determined by a prohibitive amount of subsurface information, stochastic methods such as conditional indicator simulation provide a way to compute a number of realizations of hydrofacies distributions that honor available data at their locations, with specified functions for the principal directions of spatial correlation of the hydrofacies, the scale of correlation in these directions, and the proportions. Running transport simulations using a large number of these realizations and examining the central tendency and variance of simulated contaminant travel times, or the simulated contaminant pathways, can give insight into how contaminants will move through the real system. These simulations can also be incorporated into a formal decision-analysis framework. However, the field data at a specific site commonly are insufficient for the purpose of defining the spatial correlation and proportions of the hydrofacies directly. Therefore, analog sites that are data rich need to be studied in order to find models for spatial correlation and proportions of hydrofacies that, on the basis of similar geology, can be transferred to data-poor sites. Indeed, one of the research needs identified by the National Research Council in Alternatives for Ground Water Cleanup, is the development of statistical models representing common geologic environments, which can be used to assess the variability of aquifer properties and thereby improve the success of aquifer restoration (NRC, 1994, p. 73). The proposed research will develop statistical models for aquifer properties in buried-valley aquifers, which occur across the central a nd western glaciated plains of North America and are vital to the water resources of the region. In such glacially derived aquifers, it is common to have low-K facies (e.g., till or lacustrine clay) juxtaposed with high-K facies (e.g., sand and gravel outwash). This is a renewal proposal. In the prior phase, several locations were studied in a buried-valley aquifer system located in Ohio, with the successful development of models for the hydrofacies distribution, proportions, principal directions of spatial correlation, and correlation scale in these directions. These statistical models were linked to the deposition processes that created the aquifer system, and therefore are likely to be applicable to other locations in the aquifer, and to other aquifer systems where similar depositional processes have operated. However, hydrofacies models are most useful when based on the features of numerous well-studied examples. The generality and usefulness of quantitative geostatistical models will likewise increase with their numbers, if more data-rich analogs are examined. One goal of this renewal proposal is to develop new geostatistical models for a buried-valley aquifer system in Indiana. However, the main focus of this work will be to critically evaluate methods of linking spatial correction of hydrologic parameters and geologic structure. The transition probability has been shown to be an even more interpretable representation of spatial correlation than the variography used in the prior phase. Thus the transition probability may provide a new tool for linking spatial correlation and deposition processes. The innovative aspect of this work is that it will provide a way to test the hypothesis that generic hydrofacies models can be developed for a specific class of aquifers. This will be the first comparison of spatial correlation of hydrogeologic parameters among aquifers, and is part of the longer-term goal of developing a catalogue of quantitative hydrofacies. ??

9628299 Ritzi污染物问题已经有必要了解水力传导率（K）如何分布在含水层系统中。 极值通路对污染物的运输具有主要的物理控制，因此必须量化高K和低K材料（水面）之间的边界。 尽管水平体的精确几何形状只能由过度量的地下信息确定，但诸如条件指标模拟之类的随机方法提供了一种计算多种水平分布的实现的方法，这些分布在其位置尊重可用数据，并在其位置进行可用的数据，并在其位置进行了特定的功能，以实现高定量标准的主管和这些标准的量表，并在这些方面及其量表。 使用大量这些实现的运行传输模拟，并检查模拟污染物旅行时间的中心趋势和差异，或模拟污染物的途径，可以深入了解污染物如何通过真实系统移动。 这些模拟也可以将其纳入正式的决策分析框架中。 但是，特定位点上的现场数据通常不足以直接定义水合体的空间相关性和比例。 因此，需要研究丰富数据的模拟位点，以找到用于空间相关的模型和水合的比例，这些模型可以基于相似的地质，可以将其转移到数据罚款位点。 确实，国家研究委员会在地下水清理方面确定的研究需求之一是开发代表常见地质环境的统计模型，可用于评估含水层特性的可变性，从而改善含水层修复的成功（NRC，1994年，第73页）。 拟议的研究将开发埋藏式含水层的含水层性能的统计模型，该模型发生在北美中部和西部冰川平原上，对该地区的水资源至关重要。 在这种冰川衍生的含水层中，通常具有与高k相（例如，沙子和砾石折断）并置的低k相（例如，或谷物粘土）。 这是一个续签建议。 在以前的阶段，在位于俄亥俄州的埋藏式含水层系统中研究了几个位置，并成功地开发了用于水合分布，比例，空间相关的主要方向和相关量表的模型。 这些统计模型链接到创建含水层系统的沉积过程，因此很可能适用于含水层中的其他位置，以及其他类似的沉积过程运行的含水层系统。 但是，基于众多经过良好研究的示例的特征，水合模型最有用。 如果检查更多数据的类似物，则定量地理模型的一般性和实用性也随之增加。 该更新建议的目标之一是为印第安纳州的埋藏式瓦利含水层系统开发新的地统计模型。 但是，这项工作的主要重点是批判性地评估连接水文参数和地质结构的空间校正方法。 与上一阶段中使用的变体相比，过渡概率已被证明是空间相关性更容易解释的表示。 因此，过渡概率可能会提供一个新工具，用于连接空间相关和沉积过程。 这项工作的创新方面是，它将提供一种测试假设的方法，即可以为特定类别的含水层开发通用的水面模型。 这将是含水层之间水文参数空间相关性的首次比较，并且是开发定量水面目录的长期目标的一部分。 ？