Evaluating the combined effects of source zone mass release rates and aquifer heterogeneity on solute discharge uncertainty
Evaluating the combined effects of source zone mass release rates and aquifer heterogeneity on solute discharge uncertainty
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DOI：
10.1016/j.advwatres.2018.05.010
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发表时间：
2018-07
影响因子：
4.7
通讯作者：
F. D. Barros
中科院分区：
文献类型：
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作者：
F. D. Barros
在环境敏感的位置，定量的溶质质量排放的不确定性是评估地下水污染风险的关键。溶质质量通量的强烈影响的水文地质特性的空间变异性，以及在源区的释放条件。本文提供了一个方法框架，调查普遍存在的异质性的水力传导系数和质量释放率在源区的质量流量的不确定性之间的相互作用。通过使用扰动理论，我们推导出解析和半解析表达式的溶质质量排放在控制平面在三维含水层的统计，同时占溶质质量释放率在源。导出的解决方案仅限于显示低至轻度异质性的含水层。结果表明，源区质量释放率在控制质量排放不确定性的意义。质量释放速率对平均溶质排放的相对重要性取决于源和控制平面之间的距离。另一方面，我们发现，在源区的溶质释放速率有很大的影响的方差的质量排放。在一个风险的背景下，我们还计算的峰值平均流量作为控制的水力传导率场和质量释放率在源区的空间异质性的参数的函数。所提出的基于物理的框架是面向应用的，计算效率高，能够传播不确定性从不同的参数到风险度量。此外，它还可用于初步筛选，以指导现场管理人员进行系统级敏感性分析并更好地分配资源。
Quantifying the uncertainty in solute mass discharge at an environmentally sensitive location is key to assess the risks due to groundwater contamination. Solute mass fluxes are strongly affected by the spatial variability of hydrogeological properties as well as release conditions at the source zone. This paper provides a methodological framework to investigate the interaction between the ubiquitous heterogeneity of the hydraulic conductivity and the mass release rate at the source zone on the uncertainty of mass discharge. Through the use of perturbation theory, we derive analytical and semi-analytical expressions for the statistics of the solute mass discharge at a control plane in a three-dimensional aquifer while accounting for the solute mass release rates at the source. The derived solutions are limited to aquifers displaying low-to-mild heterogeneity. Results illustrate the significance of the source zone mass release rate in controlling the mass discharge uncertainty. The relative importance of the mass release rate on the mean solute discharge depends on the distance between the source and the control plane. On the other hand, we find that the solute release rate at the source zone has a strong impact on the variance of the mass discharge. Within a risk context, we also compute the peak mean discharge as a function of the parameters governing the spatial heterogeneity of the hydraulic conductivity field and mass release rates at the source zone. The proposed physically-based framework is application-oriented, computationally efficient and capable of propagating uncertainty from different parameters onto risk metrics. Furthermore, it can be used for preliminary screening purposes to guide site managers to perform system-level sensitivity analysis and better allocate resources.