Net groundwater regeneration

The basis for the values shown in this map is the grid cell-based water balance model mGROWA (Research Center Jülich), which uses climate, land use, topography, soil map and geological maps as input data. In mGROWA, the total outflow is initially accounted for in daily resolution on the basis of the respective precipitation quantity and the calculated actual evaporation. The water storage and leaching movement in up to 5 soil layers as well as possible capillary ascent from the groundwater is taken into account. The calculated daily values are subsequently aggregated to months, years or longer periods (here 1981-2010, 1991-2020, 2011-2020). In the following, the total drainage is divided into the wastewater components direct runoff and groundwater new formation. Groundwater regeneration refers to the part of the total runoff that enters the groundwater as infiltrating leachate water. Net groundwater regeneration takes into account possible evaporative losses resulting from capillary ascent from groundwater. In the multiannual average, net groundwater regeneration can be equated with the multiannual groundwater flow (basic runoff). A detailed description of the mGROWA model and the input data used includes: LANUV Technical Report 110, Part IIa, link: https://www.lanuv.nrw.de/fileadmin/lanuvpubl/3_fachberichte/30110b.pdf Contained records (maps): Long-term averages (1981-2010, 1991-2020, 2011-2020) calculated by FZ Jülich (as of 2021)