Groundwater extracted from the Barthelasse Island aquifer, surrounded by the river Rhône (southeastern France), contributes to the drinking water supplies of 180,000 inhabitants. Owing to its location close to the river and the presence of two backwaters (oxbow lakes), the pumped groundwater is highly vulnerable to river pollution. A pumping test was conducted over 24 h to analyse and quantify the water exchange processes between the river, backwaters and groundwater. During the pumping test, isotopic (δ¹⁸O, δ²H and ²²²Rn), hydrochemical and hydrophysical monitoring of the groundwater was undertaken. Hydraulic heads were measured in pumping wells and at a piezometer located between the wells. Discrete water samples were collected at several observation points in the field, including the backwater and river. The results show mixing between three end-members, as defined by the deuterium excess and silica concentration, led by river Rhône water which had been affected by water–rock interactions over time and mixing with surface evaporated waters. The pumped water resulted from mixing between three end-members, all of which depended on the river Rhône but differed in terms of residence time in the system. Although the groundwater pumping wells are close to each other (<70 m) and have similar depths, the changes in the contributions from end-member waters at each well were different during the pumping test. Comparing isotopic tracers and geochemistry made it possible to quantify the different hydrological compartments that contribute to the groundwater pumped from the boreholes, which is critical in constructing a conceptual flow model.

从Barthelasse岛含水层提取的地下水被罗纳河（法国东南部）所包围，为18万居民的饮用水供应做出了贡献。由于其靠近河流的位置以及两个死水（牛弓湖）的存在，被抽走的地下水极易受到河流污染。在24小时内进行了抽水试验，以分析和量化河流，死水和地下水之间的水交换过程。在泵送试验，同位素（δ ¹⁸ O，δ ² H和²²²Rn），对地下水进行了水化学和水物理监测。在抽水井和位于井之间的压力计中测量液压压头。在现场的几个观测点（包括死水和河流）收集了离散的水样。结果表明，由氘和二氧化硅浓度定义的三个末端成员之间的混合是由受水-岩石相互作用影响的罗纳河水导致的，并与地表蒸发水混合。抽水是由三个末端之间的混合产生的，这些末端均取决于罗纳河，但在系统中的停留时间有所不同。尽管地下水抽水井彼此靠近（<70 m）并且深度相似，在抽水测试期间，每个井的最终成员水贡献的变化是不同的。同位素示踪剂和地球化学的比较使得量化不同的水文区室成为可能，这些水文区室对从井眼中抽出的地下水有贡献，这对于构建概念性水流模型至关重要。