Soil map of Lower Saxony 1: 50 000 — Leakage rate (1991-2020) (WMS service)

The map shows the average annual leachate rate for the 30-year period 1991-2020. The leachate rate (mm/year) from the soil is the essential size for the new groundwater formation and the transfer of substances from the soil to groundwater. It depends on the use (farm, grassland or forest), the climate and soil characteristics. It describes the amount of water that seeps from the soil body into the deeper ground. Methodologically, the size is derived according to the TUB BGR method (DWA, 2016). The main soil characteristic for the leachate rate is the plant available amount of soil water (WPFL), important climate parameters are precipitation and potential evaporation according to FAO. The degree of sealing of the soils is not taken into account in the medium-scale evaluation. The method is only applicable to arable areas with < 3.5 % slope inclination and for grassland and forest areas with < 18 % slope inclination, since the parameter surface drain does not flow into the calculation.