Collaborative Research: Fusion of Tomography Tests for DNAPL Source Zone Characterization: Technology Development and Validation

密集非水相液体（DNAPL）在世界各地的大量地点普遍存在。不同的释放历史和地质非均质性使DNAPLs在源区的分布复杂。这些水源区可能造成数十年至数百年的长期地下水污染。因此，在源区存在的DNAPLs的空间分布，质量和组成需要非常详细的特点，以便有效的修复方案可以设计。在过去的几年中，许多示踪剂技术已被引入，以提高DNAPL源区的表征。虽然这些示踪剂技术允许原位估计DNAPL饱和度的体积平均值，但迫切需要开发一种具有成本效益的技术，以高分辨率表征DNAPL的空间分布。1）开发软件/硬件包，其使用随机方法融合不同类型的信息以提供成本有效的表征，监测和预测工具的DNAPL源区，2）进行实验室实验，以测试和验证这一拟议的技术，和3）分发研究结果，以协助科学家，工程师和管理人员解决DNAPL污染问题。 智力优势：建议的新的数据处理技术，随机信息融合，结合不同类型的测量在不同的位置，在不同的尺度在迭代的方式提供最佳估计的DNAPL残差分布及其不确定性。 具体而言，它分析来自水力层析成像的信息，以识别水力非均质性首先在三维空间。 然后，它提高了估计的非均质性，将新的信息从保守的示踪剂层析成像。 之后，改进的水力非均匀性的估计被用来模拟水力层析成像，使更详细的信息，地下的响应变得可用。这一新的信息再次反馈到该技术，以更新水力异质性的估计。 迭代过程继续进行，直到所有可用的信息和测量值都被充分利用，以确定控制DNAPL空间分布的过程和变量。 在完成后，新获得的知识的过程和变量，然后结合从分区示踪剂层析成像得到的数据，以有效地描绘DNAPL残留饱和度在源区的空间分布。 提出的层析成像技术和随机融合的信息算法进行了测试和验证在沙箱。所提出的研究的成功不仅在一般的估计理论的进步，但也是我们的技术表征和监测subground.Broader影响：所提出的随机融合技术可以集成不同的表征技术在不同的地质条件。它也适用于DNAPL源区表征的所有阶段，包括初步筛选，现场表征，补救和长期监测。 一个基于网络的虚拟液压/示踪剂层析成像实验室将被创建，并提供给世界各地的任何学生，教育工作者，从业者和研究人员。 我们相信这个虚拟实验室将激发创造力，不仅彻底改变经典的地下水文学，而且也改变水文科学的其他学科。 例如，使用我们的随机信息融合技术，人们可能能够同化气象信息，如照明和降水作为替代激发源的层析成像调查的地下环境在大scaleseing到地球。

0229713IllmanDense Nonaqueous Phase Liquids (DNAPLs) are prevalent at a large number of sites throughout the world. The variable release history and geologic heterogeneity make the distribution of DNAPLs in the source zone complex. These source zones can contribute to long-term groundwater contamination for decades to centuries. Therefore, the spatial distribution, mass, and composition of DNAPLs present in the source zone need to be characterized in great detail so that efficient remediation schemes can be designed. During the last few years, many tracer techniques have been introduced to enhance the characterization of DNAPL source zones. While these tracer techniques allow for the in situ estimation of volume-averaged values of DNAPL saturation, there is an urgent need for the development of a cost-effective technology to characterize the spatial distribution of DNAPLs at high resolutions.The objectives of this proposed study are: 1) to develop a software/hardware package that fuses different types of information using a stochastic approach to provide a cost-effective characterization, monitoring, and predictive tool for the DNAPL source zone, 2) to conduct laboratory experiments to test and verify this proposed technology, and 3) to distribute the results of the research to assist scientists, engineers, and managers to solve DNAPL contamination problems. Intellectual Merit: The proposed new data processing technique, stochastic information fusion, combines different types of measurements taken at different locations over different scales in an iterative manner to provide the best estimate of the DNAPL residual distribution and its uncertainty. Specifically, it analyzes the information derived from hydraulic tomography to identify hydraulic heterogeneity first in three-dimensions. It then improves the estimate of the heterogeneity by incorporating new information acquired from the conservative tracer tomography. Afterward, the improved estimate of hydraulic heterogeneity is used to simulate the hydraulic tomography such that more detailed information about the response of the subsurface becomes available. This new information again is fed back to the technique to update the estimate of hydraulic heterogeneity. The iterative process continues until all available information and measurements are fully utilized in identifying the processes and variables that control the spatial distribution of DNAPLs. Upon completion, the newly derived knowledge of the processes and variables are then combined with data derived from the partitioning tracer tomography to effectively delineate the spatial distribution of DNAPL residual saturation in the source zone. The proposed tomography technique and the stochastic fusion of information algorithm are to be tested and validated in a sandbox. Success of the proposed research advances not only estimation theory in general but also our technologies for characterizing and monitoring the subsurface.Broader Impacts: The proposed stochastic fusion technology can be integrated with different characterization techniques in diverse geological conditions. It is also amenable to all stages of DNAPL source zone characterization including initial screening, site characterization, remediation, and long-term monitoring. A web-based virtual hydraulic/tracer tomography laboratory will be created and be available to any student, educator, practitioner, and researcher around the world. We believe this virtual laboratory will stimulate creativity to revolutionize not only classical subsurface hydrology but also other disciplines of hydrologic sciences. For example, using our stochastic information fusion technology, one may be able to assimilate meteorological information such as lighting and precipitation as alternative excitation sources for tomographic surveys of the subsurface environment at large scalesseeing into the earth.