Collaborative Research on Reactive Transport: Modeling Spatial Cross-Correlation between Hydraulic and Reactive Aquifer Attributes as Determined by Sedimentary Architecture

Ritzi反应性运移合作研究：模拟水力和反应性含水层属性之间的空间相互关系，由沉积体系结构确定反应性物质运移的模型需要表示水力和反应性属性，如渗透率(K)和吸附分配系数(Kd)在空间中如何变化。还没有一个模型纳入这些属性的协变性的真实特征，这是在以前的详细实地研究中观察到的。这是反应输运模型的一个重要限制。我们假设沉积沉积物中水力属性和反应性属性之间的空间协变性取决于不同单元类型之间的转换，这很像以前对水力属性本身的空间变异性所显示的那样。这一假设是基于这样一个概念，即沉积物的侵蚀、输送和沉积包括自然分选沉积物颗粒的过程，并产生组成(矿物学)和粒度大小不同的单元类型。我们的假设是基于对博尔登含水层收集的岩相、k和Kd数据的观察和初步测试。拟议项目的具体目标是开发和探索一种新的模型，该模型将水力属性和反应性属性的空间协变性表示为沉积矿床的等级结构的函数，以及在不同相关尺度上的岩性单元内部和之间转换的可能性。该模型将代表在最近的实地研究中观察到的以下关系：(1)在一些单位类型中，点相关可能是正的，而在其他单位类型中，点相关可能是不相关的或负的。(2)如果存在相关性，则不必是完美的。(3)当跨单位类型转换时，跨单位边界翻译的滞后互相关可能是正的，而在其他单位类型的转换中可能是负的。(4)在沉积建筑内，可以有与不同尺度的单元类型相关联的多个相关的整体对比尺度。这些活动将包括从一个具有良好特点的实地地点编制适当的数据集，计算模型中代表层次内和层次间关系的术语，并了解这些术语中的哪些对综合尺度上的相互关联有重大贡献，综合尺度是观察羽流扩散的尺度。一旦我们了解了哪些术语是重要的，我们将对它们进行建模，作为开发复合模型功能的一部分。该项目将涉及两名在地球化学和地质统计学方面有专长的水文地质学家和一名沉积学家之间的合作。拟议活动的智力优点：解释性计算建模研究尚未能够同时再现在受控现场研究中观察到的非理想运输行为的所有方面。这有力地表明，对反应性运输的基本方面还没有完全了解。我们在这里假设，在解释的反应输送模型中，缺乏对水力和反应属性之间的协变性的适当表示，这是此类研究的一个重要限制。拟议的项目将加强对水力和反应属性的协变性的全面了解。它将帮助研究界超越目前用于表示协变性的简单化范式，并导致开发一个基于实地观察建立起来的有良好基础的替代模型。因此，我们建议的工作将通过改进我们对反应传输模型中的水力和反应属性的表示来对解释性反应传输建模产生重要影响。建议活动产生的广泛影响：项目的更广泛的影响属于两个一般领域：通过直接或间接参与项目来加强学生培训的影响和通过实现对沉积含水层内有机污染物命运的更好理解来造福社会的影响

0538037RitziCollaborative Research on Reactive Transport:Modeling Spatial Cross-Correlation between Hydraulic and ReactiveAquifer Attributes as Determined by Sedimentary ArchitectureModels for reactive mass transport require a representation of how hydraulic and reactive attributes, such as permeability (k) and the sorption distribution coefficient (Kd), vary in space. No model has yet incorporated the authentic features of the co-variability of these attributesobserved in previous, detailed field studies. This is an important limitation of reactive transport models. We hypothesize that spatial co-variability between hydraulic and reactive attributes in sedimentary deposits depends upon transitions across unit types, much as has been previously shown for spatial variability of hydraulic attributes themselves. The hypothesis is predicated on the concept that sediment erosion, transport and deposition include processes which naturally sort sediment grains and create unit types that differ in composition (mineralogy) as well as grain size.Our hypothesis is based on observations and preliminary testing using lithofacies, k, and Kd data collected for the Borden aquifer. The specific goal of the proposed project is to develop and explore a new model that represents the spatial co-variability of hydraulic and reactive attributes as a function of the hierarchical architecture of sedimentary deposits and the probabilities for transitioning within and between lithologic units across different, relevant scales. The model will represent the following relationships observed in recent field studies: (1)The point-correlation may be positive within some unit types and uncorrelated or negative within others. (2) If correlation exists, it need not be perfect. (3) The lag cross-correlation with translation across unit boundaries may be positive when transitioning across certain unit types and negative across others. (4) There can be multiple, relevant integral scales of correlation associated with the different scale of unit types within the sedimentary architecture. The activities will include developing an appropriate data set from a well-characterized field site, computing theterms of the model which represent relationships within and across hierarchical levels, and gaining an understanding of which of these terms contribute significantly to the cross-correlation at the composite scale, which is the scale at which plume spreading is observed. Once we understand which terms are significant, we will model them as a part of developing the composite model function. The project will involve collaboration among two hydrogeologists, with expertise in geochemistry and geostatistics, and a sedimentologist. Intellectual merit of the proposed activity: Interpretive computational modeling studies have not yet been able to simultaneously reproduce all aspects of nonideal transport behavior that have been observed in controlled field studies. This strongly suggests that fundamental aspects of reactive transport are not yet fully understood. We posit here that lack of proper representation of the co-variability between hydraulic and reactive attributes within theinterpretive reactive transport models is a significant limitation within such studies. The proposed project will enhance overall understanding of co-variabilty of hydraulic and reactive attributes. It will help the research community to move beyond the simplistic paradigm currently used for representing co-variability and lead to development of a well-grounded alternative model built upfrom field observations. Thus, the work we propose will have an important impact on interpretive reactive transport modeling by improving our representation of the hydraulic and reactive attributes within reactive transport models.Broader impacts resulting from the proposed activity: The broader impacts of theproject fall within two general realms: those that enhance student training through direct or indirect participation in the project and those that benefit society through realization of improved understanding of the fate of organic contaminants within sedimentary aquifers