Predicting and managing water resources at regional scale under different climate and socio-economic scenarios is crucial to support drinking water supply and other sectors. At the same time, protecting rivers and wetlands from pollutions and droughts is essential and must include groundwater given its contribution to surface water. Yet, assessing temporal and spatial variability of groundwater contributions to surface water is constrained due to limited observations. This study aims to quantify the spatio-temporal distribution of groundwater discharge (hereafter called “GW discharge”) zones, i.e. the groundwater flow to rivers and wetlands, estimated by calibrated regional groundwater flow models (French AquiFR platform). We compare simulation results with two types of surface observations: (i) the spatial distribution of surface water (BD TOPO, RAMSAR and Natura 2000 database) and (ii) an innovative datasets, the river intermittence observed in headwaters (ONDE network). Results show that simulated GW discharge zones are consistent with the observed location of rivers and wetlands. Time variations in GW discharge are well correlated with the intermittence observed at 396 of the 515 selected stations. Of these, groundwater model continues to feed surface water upstream of the station for ∼75 % of observed river drying up events, which may be consistent with a small alluvial flow. The groundwater withdrawals are shown to have a strong impact on the GW discharge and thus on the river intermittence.

中文翻译：

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区域地下水模型是否适合模拟湿地、河流和间歇性水资源？以法国AquiFR平台为例


在不同气候和社会经济情景下预测和管理区域范围内的水资源对于支持饮用水供应和其他部门至关重要。与此同时，保护河流和湿地免受污染和干旱至关重要，而且必须包括地下水，因为地下水对地表水有贡献。然而，由于观测有限，评估地下水对地表水贡献的时间和空间变化受到限制。本研究旨在量化地下水排放（以下简称“GW 排放”）区域的时空分布，即通过校准的区域地下水流模型（法国 AquiFR 平台）估计的流入河流和湿地的地下水流量。我们将模拟结果与两种类型的地表观测进行比较：(i) 地表水的空间分布（BD TOPO、RAMSAR 和 Natura 2000 数据库）和 (ii) 创新数据集，即在源头观测到的河流间歇性（ONDE 网络）。结果表明，模拟的GW排放区与观测的河流和湿地位置一致。 GW 放电的时间变化与 515 个选定站点中 396 个观测到的间歇性密切相关。其中，在观察到的河流干涸事件的约 75% 中，地下水模型继续向该站上游提供地表水，这可能与小冲积流一致。研究表明，地下水抽取量对 GW 流量有很大影响，从而对河流间歇有很大影响。