CAREER: Mass Transport in Groundwater: an Integration of Research and Experiential Education

职业：地下水中的物质传输：研究与体验式教育的结合

• 批准号: 1261005
• 负责人: Kamini Singha
• 金额: $ 25.52万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1261005&HistoricalAwards=false
• 关键词: CAREER; Mass; Transport; Groundwater; Integration

Soluble contaminants or tracers migrate through natural systems defining concentration versus time curves that vary between sample locations. Often, these curves show long tails that are not described by the processes of advection and dispersion. Whether we need to predict evolution of natural systems or the quality of our water supply, we must be able to quantitatively predict such tailing behavior. The reliability of contaminant transport predictions depends on a good understanding of in-situ flow and transport processes; however, large contrasts, complex connectivity, and extreme spatial localization of hydraulic properties combine with sparse data to limit our understanding of fundamental processes and properties controlling field-scale hydrologic behavior. This research looks to help answer the following question: Under what scenarios canlong tailing of concentration histories be described by commonly used advective-dispersive models given hydraulic conductivity heterogeneity, versus the need for bicontinuum models with local diffusion between mobile and less mobile porosity domains?Bicontinuum mass transfer has been used to explain complex transport behavior in some environments, but experimental verification of this process is problematic because geochemical samples only represent the mobile component of the pore space, making determination of processes in the immobile domain impossible. Recently, the PI and colleagues have demonstrated that electrical geophysical techniques provide ameans of verifying the occurrence of bicontinuum transport and estimating the parameters which control these processes by sampling the total pore space, rather than just the mobile domain. While these results show promise for using remotely sensed data for directly estimating hydrologic parameters controlling mass transfer?immobileporosity and mass-transfer rate?in situ, determining when dual-domain systems control transport is unclear. In particular, it is not clear what scales of mass transfer rates (or diffusion lengths) and immobile porosity fractions can be practically investigated with this approach, or heterogeneity controls on transport. The objectives of this research are to determine 1) whether solutes locally diffuse between mobile and less mobile zones at three field sites of differing geology, and 2) how mass transfer processes within and between heterogeneous zones affect our macroscopic view of solute transport in the field.Tied to this research is the development of an integrated hydrogeophysics summer course, where undergraduate researchers will combine field experimentation, in-class instruction, and numerical modeling to develop and test hypotheses regarding the processes controlling transport under different regimes. This field camp will be run in collaboration with three HBCUs (Historically Black Colleges and Universities) partnered with Penn State and the Summer Research Opportunity Program (SROP), a summer-long internship that engages students from minority groups and institutions in cutting-edgeresearch at majority institutions of the Committee on Institutional Cooperation.

可溶性污染物或示踪剂通过自然系统迁移，从而定义在样品位置之间变化的浓度与时间曲线。 通常，这些曲线显示的长尾是平流和弥散过程所不能描述的。无论我们需要预测自然系统的演变还是我们的供水质量，我们都必须能够定量预测这种拖尾行为。污染物输运预测的可靠性取决于对原位流动和输运过程的良好理解;然而，水力特性的大对比、复杂连通性和极端空间定位联合收割机与稀疏数据相结合，限制了我们对控制现场尺度水文行为的基本过程和特性的理解。 这项研究旨在帮助回答以下问题：在什么情况下可以长期拖尾的浓度历史被描述的常用的对流扩散模型给定的水力传导率的异质性，与局部扩散之间的移动的和少移动的孔隙度域的双连续体模型的需要？双连续体质量传递已被用来解释复杂的运输行为在某些环境中，但这个过程的实验验证是有问题的，因为地球化学样品只代表移动的组成部分的孔隙空间，不可能确定的过程中的im移动的域。 最近，PI和同事们已经证明，电地球物理技术提供了验证双连续体传输的发生和估计控制这些过程的参数，通过采样的总孔隙空间，而不仅仅是移动的域的手段。虽然这些结果表明，使用遥感数据直接估计水文参数控制传质的承诺？不动孔隙率和传质速率？在原位，确定何时双域系统控制运输尚不清楚。 特别是，目前还不清楚什么规模的传质速率（或扩散长度）和不动孔隙率分数可以实际调查与这种方法，或异质性控制运输。 本研究的目标是确定1）在三个地质不同的野外地点，溶质是否在移动的区和移动的性较差的区域之间局部扩散，以及2）异质区域内和之间的质量传递过程如何影响我们对野外溶质迁移的宏观看法。与这项研究相关的是综合水文地球物理学夏季课程的开发，本科研究人员将联合收割机现场实验、课堂教学和数值建模，以开发和测试有关过程控制不同制度下的运输假设。 该实地考察营将与三所HBCU（历史上的黑人学院和大学）合作，与宾夕法尼亚州立大学和夏季研究机会计划（SROP）合作，这是一个为期一个夏天的实习，让来自少数群体和机构的学生参与机构合作委员会大多数机构的前沿研究。