Contaminant Plume Migration in an Aquifer: Finite Element Modeling for the Analysis of Remediation Strategies: A Case Study

Groundwater resources are becoming more and more endangered of being depleted by over-exploitation and of being polluted as a consequence of environmentally insensitive economic activities and population growth in many regions and countries of the world. Causes and consequences of quantitative and qualitative changes in groundwater states can be separated by decades and centuries. Once contaminated or depleted, groundwater resources may be permanently impaired. This fact becomes especially obvious in the case of groundwater pollution by hazardous wastes. Necessary remediation strategies may be extremely time and money consuming. Therefore, the optimal design of such remediation strategies is of great importance. The paper describes the results of a case study dealing with historical and predictive modeling of the migration of a real contaminant plume in an alluvial aquifer threatening the nearby operating extraction wells for municipal water supply. As a modeling case study it primarily aims at modeling and examining current and intended remediation strategies. The consequences and benefits of a hydraulic barrier in continuous or intermittent operation and their combination with pumpage from interception wells are investigated and discussed. For these purposes a horizontal plane transport model based on a finite element approach has been developed and applied. The model has been tested and calibrated through a history matching procedure comparing model computations with observed field data, where hydrodynamic dispersivities are identified as principal parameters. The obtained prognostic results allow several practical conclusions on the design of remediation strategies. The used finite element model simulator FEFLOW has proved to be a convenient and powerful tool in modeling the complex flow and transport processes of the contaminant plume. It demonstrates the abilities in prospective simulations for decision purposes

Содержание. Секция 07 - Оптика и спектроскопия

The remarkable complexity of soil and its importance to a wide range of ecosystem services presents major challenges to the modeling of soil processes. Although major progress in soil models has occurred in the last decades, models of soil processes remain disjointed between disciplines or ecosystem services, with considerable uncertainty remaining in the quality of predictions and several challenges that remain yet to be addressed. First, there is a need to improve exchange of knowledge and experience among the different disciplines in soil science and to reach out to other Earth science communities. Second, the community needs to develop a new generation of soil models based on a systemic approach comprising relevant physical, chemical, and biological processes to address critical knowledge gaps in our understanding of soil processes and their interactions. Overcoming these challenges will facilitate exchanges between soil modeling and climate, plant, and social science modeling communities. It will allow us to contribute to preserve and improve our assessment of ecosystem services and advance our understanding of climate-change feedback mechanisms, among others, thereby facilitating and strengthening communication among scientific disciplines and society. We review the role of modeling soil processes in quantifying key soil processes that shape ecosystem services, with a focus on provisioning and regulating services. We then identify key challenges in modeling soil processes, including the systematic incorporation of heterogeneity and uncertainty, the integration of data and models, and strategies for effective integration of knowledge on physical, chemical, and biological soil processes. We discuss how the soil modeling community could best interface with modern modeling activities in other disciplines, such as climate, ecology, and plant research, and how to weave novel observation and measurement techniques into soil models. We propose the establishment of an international soil modeling consortium to coherently advance soil modeling activities and foster communication with other Earth science disciplines. Such a consortium should promote soil modeling platforms and data repository for model development, calibration and intercomparison essential for addressing contemporary challenges