CAREER: Wavelet Analysis of Scale Effects on Subsurface Flow and Transport

含水层性质的空间变异性影响污染物在地下的移动和扩散。由于不能获得非均质含水层性质的完整空间表示，因此预测溶质在多孔介质中的运移具有不确定性。了解含水层性质的空间变异性及其对流动和运移的影响，对于可靠地预测溶质运移、补救系统的最佳设计、风险评估、供水井的选址等至关重要。含水层的非均质性在多个尺度上发生；然而，对含水层性质的测量往往只在有限的尺度上进行。这些测量尺度可能与控制地下流动和输送的尺度不一致。在这项研究中，我们将分析影响地下水流动和溶质运移的含水层属性的主导尺度，并确定主导尺度与含水层属性的物理和化学非均质性之间的关系。连续小波变换(CWT)将用于从含水层属性和系统状态(水头和溶质浓度)的空间分布数据集中提取尺度信息。CWT是一个在多个尺度上提取局部信息的工具。这项技术将利用合成数据集和数值模拟进行开发和测试。随后将与实验室和现场尺度流动和运移实验的数据一起使用，以确定含水层性质的主要尺度；系统状态的主要尺度的演变；以及主要尺度、非均质程度和对溶质运移的影响之间的关系。了解流动和运移的主要尺度及其与含水层非均质性之间的关系，将有助于对含水层特征进行更有针对性的抽样，并改进对地下流动和运移的预测。教育目标是教会学生认识物理系统中的变异性和不确定性，并进行造成这种不确定性的工程设计和分析；通过强调工程学和科学知识的实际应用，改进科学和工程学教育；鼓励妇女和代表性不足的少数群体考虑技术领域。将通过接触用于分析和设计的现实、复杂的数据集；伴随讲课的实际动手活动；以及向代表性不足的少数群体和妇女推广科学和工程领域的外联活动来实现这些目标。

0237702NeupauerSpatial variability of aquifer properties affects the movement and spread of contaminants in the subsurface. Since a complete spatial representation of the heterogeneous aquifer properties cannot be obtained, predictions of solute movement through porous media contain uncertainty. An understanding of the spatial variability of aquifer properties and their effects on flow and transport is essential for making reliable predictions of solute transport, a necessary component of optimal design of remediation systems, risk assessment, siting of water supply wells, and others. Aquifer heterogeneity occurs at multiple scales; however, measurements of aquifer properties are often made at only a limited number of scales. These measurement scales may not correspond to the scales that control subsurface flow and transport. In this study, we will analyze dominant scales of aquifer properties that affect groundwater flow and solute transport and identify relationships between dominant scales and physical and chemical heterogeneity of aquifer properties. Continuous wavelet transforms (CWT) will be used to extract scale information from data sets of the spatial distribution of aquifer properties and system states (hydraulic head and solute concentration). The CWT is a tool that extracts local information at multiple scales. The technique will be developed and tested using synthetic data sets and numerical simulations. It will subsequently be used with data from laboratory- and field-scale flow and transport experiments to identify dominant scales of aquifer properties; the evolution of dominant scales of system states; and the relationships between dominant scales, the degree of heterogeneity, and the effects on solute transport. Knowledge of the dominant scales of flow and transport and the relationship between them and aquifer heterogeneity will facilitate more targeted sampling for aquifer characterization and improved predictions of subsurface flow and transport.The educational goals are to teach students to recognize variability and uncertainty in physical systems and to perform engineering design and analysis that accounts for this uncertainty; to improve science and engineering education by emphasizing the practical applications of engineering and science knowledge; and to encourage women and underrepresented minorities to consider technical fields. They will be achieved through exposure to realistic, complex data sets for analysis and design; practical hands-on activities to accompany lectures; and outreach activities to promote science and engineering fields to underrepresented minorities and women.