National scale potential recharge values for France
A national scale map that shows yearly LTA potential recharge values (mm/year) calculated over France. Values are calculated at daily time step and averaged over the period 1981 – 2010 The map presents the mean yearly potential groundwater recharge (refers to the part of the precipitation not stored in the soil, nor used by the vegetation) that infiltrates to potentially reach the aquifers calculated over the period 1981-2010 and at the spatial scale of 8 x 8 km grid cells and provided in mm/years
Effective precipitation is simulated at the daily time step for each 8x8 km gridcell, using the averaged result of three simple water balance models (Thornthwaite (1948), Edijatno & Michel (1989) and Dingman (2002)) and considering the maximum soil water content (French national soil map, DoneSol INRA (2014)). Water balance models are forced using the SAFRAN meteorological reanalysis data set available at the same resolution (Vidal et al., (2010)). To estimate an effective precipitation infiltration ratio (EPIR), average IDPR values (Mardhel et al., 2021) are compared to base flow computed using the Wallingford method (Gustard et al., 1992) on a set of representative and non-influenced French river basins. The EPIR values are then projected over the 8x8 km grid and multiplied by effective precipitation to obtain potential recharge.