Development of River-Stage Tomography for Characterizing Groundwater Basins

Jim Tian-Chyi Yeh，亚利桑那大学研究开发用于表征地下水盆地的河流-状态层析成像技术研究开发一种可靠的流域尺度含水层表征方法，将大大提高模拟地下水流域通量和运移的可靠性。在不实际的情况下，通过抽水试验在绵延数百平方公里的盆地中诱发应力，河流水文曲线的下游通道产生可以利用的含水层应力。影响范围大、发生频率高、激励在空间上的缓减，使河流阶段的变化成为流域尺度水力层压测量中用于绘制含水层非均质性的理想能量来源，从而监测含水层的响应。之前的工作已经证明了用于地下水盆地表征的二维深度平均耦合河流和地下水模型的可行性，这个新项目现在正在扩展过去的工作，以开发用于含水层表征的三维模型。该方法正通过对台湾中西部高强度仪器测量的草水河冲积扇进行测试和验证。该方法从大量数据出发，依次确定不同位置的河流阶段变化引起的应力，并在许多井中记录含水层响应。然后采用基于地质统计学的随机参数估计方法来估计代表非均质含水层的参数。该方法通过认识到降水驱动的水文过程在时间和空间上的周期性变化，为估算含水层水文地质参数提供了非完全重叠的信息，从而引入了层析成像范式。这项工作的目标是通过更好地了解河流和地下水流域之间的相互作用，从而产生广泛的影响，从而支持水资源管理，并通过联合用水加强环境保护。从业者还将从一种非侵入性技术中受益匪浅，该技术可用于表征流域水文非均质性和与表征相关的不确定性。他们还将获得一个宝贵的工具，用于评估气候变化对地下水资源的影响。将努力通过通讯宣传和解释这种方法，以促进这些贡献的应用。

Jim Tian-Chyi Yeh, Univ. of ArizonaDevelopment of River-State Tomography for Characterizing Groundwater BasinsThe achievable reliability in modeling fluxes and transport in groundwater basins would be greatly enhanced by a practical method for reliable basin-scale aquifer characterization. Where it is not practical to conduct pumping tests to induce stresses throughout a basin stretched over hundreds of square kilometers, the downstream passage of river hydrographs create aquifer stresses that can be used. The large area of influence, frequency of occurrence, and spatial mitigation of the excitation make river stage variation an ideal energy source for use in basin-scale hydraulic tomographic surveys to map aquifer heterogeneity where aquifer responses are monitored. Previous work has demonstrated the viability of a 2D depth-average coupled river and groundwater model for groundwater basin characterization and this new project is now engaged in expanding on this past work to develop a 3D model for aquifer characterization. The approach is being tested and validated through application to the intensely instrumented Cho-Shui River alluvial fan in central western Taiwan. The method starts from an immense amount of data to determine the stress induced by river-stage variation at various locations sequentially and aquifer responses recorded in numerous wells. It then employs a stochastic parameter estimating procedure using geo-statistically-based methodology to estimate parameters for representing a heterogeneous aquifer. The approach imports the tomography paradigm by recognizing that the recurrent nature of temporally and spatially variable precipitation-driven hydrologic processes provides non-fully overlapping information for estimating aquifer hydrogeologic parameters. The work is targeted to have broad impacts through greater understanding of the interactions between rivers and groundwater basins that would support water resources management and greater environmental protection through conjunctive water use. Practitioners will also greatly benefit by having a non-invasive technology for characterizing basin hydrologic heterogeneity and the uncertainty associated with the characterization. They will also gain a valuable tool for use in evaluating the effects of climate change on groundwater resources. An effort will be made to publicize and explain the methodology through communications that would facilitate applying these contributions.