GeoPEARL is a spatially-distributed model, calculating the leaching potential of a substance for the area of potential use. Currently, GeoPEARL is used in the second tier of the decision tree for evaluating the leaching potential of pesticides in the Netherlands. The spatial criterion in the decision tree states that the long-term average concentration of a pesticide or its relevant metabolites at 1 meter depth should not exceed the EU drinking water limit of 0.1 µg/L for at least 90% of the surface area where the pesticide is potentially used.
GeoPEARL runs for 6405 unique combinations of basic model inputs (soil type, climate district, land-use type, groundwater depth class etc.). Grid cells that share the same unique combination of parameters are referred to as ‘plots’. During the creation of the spatial schematisation, results from a regional-scale hydrological model were used. In this way, it is possible to quantify fluxes and residence times of chemicals in the saturated zone. Also, it is possible to quantify the fluxes into local surface waters.
