Chesnaux R, Santoni S, Garel E, Huneau F
Université de Corse Pascal Paoli, Faculté des Sciences et Techniques, Laboratoire d'Hydrogéologie, Campus Grimaldi, BP 52, F-20250, Corte, France.
CNRS, UMR 6134, SPE, F-20250, Corte, France.
Ground Water. 2018 Nov;56(6):986-992. doi: 10.1111/gwat.12794. Epub 2018 Jun 12.
An analytical solution to calculate the recharge of unconfined aquifers with Dupuit-Forchheimer type flow conditions is proposed. This solution is derived from an existing closed-form analytical solution initially developed to determine groundwater travel time when the recharge of the aquifer is known. This existing solution has been modified to determine recharge when groundwater travel time is known. An illustration is given with a field case example for the Bonifacio aquifer of the island of Corsica (France), in the Mediterranean. In this aquifer, previously established differences in groundwater residence time between two water samples were determined from anthropogenic atmospheric gas (chlorofluorocarbons and sulfur hexafluoride) measurements. The time difference is entered into the new analytical solution to determine recharge. The calculations yield a value of average recharge that agrees with the results obtained by several other methods that were presented in previous studies to assess the recharge of the Bonifacio aquifer. Also presented in this study is a sensitivity analysis of the new analytical solution, to quantify the influence of different parameters that control recharge: hydraulic conductivity, effective porosity and the groundwater travel time. This study illustrates how geochemical data can be combined with physical models to measure recharge. Such an approach could be adopted in other homogeneous aquifers worldwide that satisfy Dupuit-Forchheimer type flow conditions.
提出了一种用于计算具有Dupuit-Forchheimer型流动条件的无压含水层补给量的解析解。该解源自一个现有的封闭形式解析解，该解析解最初是为在已知含水层补给量的情况下确定地下水运移时间而开发的。现对该现有解进行了修改，以便在已知地下水运移时间时确定补给量。文中给出了一个实例，即法国科西嘉岛博尼法乔含水层的现场案例。在地中海的该含水层中，先前通过人为大气气体（氯氟烃和六氟化硫）测量确定了两个水样之间地下水停留时间的差异。将时间差代入新的解析解中以确定补给量。计算得出的平均补给量值与先前研究中用于评估博尼法乔含水层补给量的其他几种方法所得结果一致。本研究还对新的解析解进行了敏感性分析，以量化控制补给量的不同参数（水力传导率、有效孔隙率和地下水运移时间）的影响。本研究说明了如何将地球化学数据与物理模型相结合来测量补给量。这种方法可应用于全球其他满足Dupuit-Forchheimer型流动条件的均质含水层。
