ISSN 1000-3665 CN 11-2202/P

    傍河含水层开采量和水文地质参数反演的地下水监测井布设最优试验研究

    Optimal experimental design for estimating the groundwater exploitation and hydrogeological parameters of riverbank aquifer

    • 摘要:
      目的 傍河含水层是重要供水水源地,地下水动态受到开采、地表水-地下水相互作用等多种要素影响,如何通过合理布设地下水监测井联合反演开采量与水文地质参数,是区域地下水资源评估及合理开发利用的核心问题之一。
      方法 针对傍河均质潜水含水层,结合Kriging替代模型,采用马尔可夫链蒙特卡洛方法构建效用函数开展序贯监测网优化设计,实现了傍河含水层地下水开采量及河床沉积物渗透系数(Kr)的联合反演。
      结果 通过案例分析表明,Kriging替代模型可以有效替代地下水数值模型,提高模型运算效率;基于序贯监测方法的优化监测方案能够充分捕捉到傍河含水层流场变化,识别最优监测布设位置,实现多个开采井地下水开采量及Kr的联合精确反演;生成的最优监测方案反演参变量精度优于随机监测方案;
      结论 通过对比不同布局的最优监测井布设方案发现,开采井及河流附近等地下水水力梯度显著变化处,是布设地下水监测井的关键区域。研究可为傍河含水层监测井布设、地下水资源评价与开发利用提供科学支撑。

       

      Abstract: Riverbank aquifers are of great importance for water supply sources, and their groundwater dynamics are strongly influenced by pumping and groundwater-surface water interactions. Designing effective groundwater monitoring networks to estimate the groundwater exploitation and invert hydrogeological parameters is one of the core issues in the assessment of the sustainable utilization of regional groundwater resources. In this study, a surrogate model based on the Kriging method for the numerical groundwater model was established for a homogeneous unconfined riverbank aquifer, and Markov chain Monte Carlo method was used to construct an optimal design of the sequential monitoring network with the expectation of the a priori to a posteriori relative entropy of the parameters as the utility function. It enables the joint inversion of the groundwater exploitation and the hydraulic conductivity of riverbed sediment (Kr) in the riverbank aquifer. The case study demonstrates that the surrogate model based on the Kriging method can effectively replace groundwater numerical models, enhancing computational efficiency. The optimized monitoring scheme method based on the proposed method can adequately capture changes in the flow field of the riverbank aquifer and accurately estimate the groundwater exploitation and the parameter Kr. Comparative analyses between the optimized monitoring strategy and random monitoring strategies indicate that the optimized approach achieves superior accuracy in parameter inversion. Comparisons of many sets of optimal monitoring well placement schemes with different layouts show that areas around pumping wells and near rivers with significant changes in the hydraulic gradient are key areas for the placement of monitoring to effectively estimate the groundwater exploitation and invert the Kr. This study provides scientific support for the design of monitoring well networks in riverbank aquifers and offers valuable insights for groundwater resource evaluation and sustainable management.

       

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