Artificial basins are used to recharge groundwater by many municipalities to improve the sustainability of storm water management. Despite its increasing operational implementation, artificial recharge still raises numerous questions related to its impact on groundwater quality. In this paper, a 3D numerical model of MAR basin/aquifer system was implemented in order to simulate the fate of water and pollutants. It was used to illustrate the complex distribution in time and space of a tracer contaminant injected in the basin. The model was based on a well instrumented storm water infiltration basin located in Chassieu (Lyon area, France). The well-known Richards model was used to simulate the water flow in the saturated and unsaturated zone of the study site. The transfer of solutes in the basin/aquifer system was modelled by the advection-dispersion-equation (ADE). The model was calibrated during a rain event using hydraulic head and electric conductivity data from a set of piezometers located around the basin. The flow model was validated on a one month period of basin operation presenting several rain events. The model was then used to simulate the fate of a solute pollutant considered as a tracer during a high intensity rain event. This simplified test case illustrated the mechanism of capillary trapping in the vadose zone and the effect of sampling point location on concentration measurements. Three main results were obtained: (1) capillary trapping promoted a retention of up to 20% of the injected tracer in the vadose zone, (2) 0 to 24% of the injected solute concentration could be recovered depending on the piezometer location, (3) the averaged concentration decreased by 50% if the measuring device is lowered by 5 m under the water table. These results were strongly site and event dependant but observed trends should be considered while discussing punctual water quality measurements used to monitor MAR systems. It also allowed to suggest some guidelines for sampling point positioning.

许多市政当局都使用人工盆地来补给地下水，以提高雨水管理的可持续性。尽管人工补给越来越多，但人工补给仍然引起许多与其对地下水质量的影响有关的问题。为了模拟水和污染物的命运，本文建立了MAR盆地/含水层系统的3D数值模型。它用来说明在盆地中注入的示踪污染物在时间和空间上的复杂分布。该模型基于位于Chassieu（法国里昂地区）的仪器完善的雨水渗透盆地。众所周知的Richards模型被用来模拟研究场地饱和和非饱和区域的水流。盆地/含水层系统中溶质的转移通过对流扩散方程（ADE）进行建模。在雨天期间，使用水头和来自盆地周围的一组压力计的电导率数据对模型进行了校准。该流模型在流域运行一个月期间进行了验证，并呈现出几次降雨事件。然后将该模型用于模拟在高强度降雨事件中被视为示踪剂的溶质污染物的去向。这个简化的测试用例说明了在渗流区内毛细管捕集的机理以及采样点位置对浓度测量的影响。获得了三个主要结果：（1）毛细管捕集促进了在渗流区内保留高达20％的注入示踪剂，（2）根据压力计的位置，可以恢复注入的溶质浓度的0％到24％。（3）如果将测量设备降低到地下水位以下5 m，则平均浓度降低50％。这些结果在很大程度上取决于地点和事件，但在讨论用于监测MAR系统的准时水质测量时应考虑观察到的趋势。它还允许为采样点定位提供一些指导。