Development of a Tool for Estimation of Pesticide Occurrence in Surface Water Under Danish Conditions

The Danish Environmental Protection Agency initiated in 1998 the development of a modelling tool for estimation of pesticides in surface water in connection with registration of pesticides. The organisations involved in the development are DHI - Water and Environment, National Environmental Research Institute, Danish Institute of Agricultural Science (Flakkebjerg), and the Counties of Funen and Northern Jutland. Two existing small 1st order catchments are chosen as basis for the scenarios. Models are calibrated and validated on existing flow and pesticide data for the two catchments. Finally, the models are modified to create scenarios for registration purposes. The approach differs from the more traditional approach where one field is placed along a stream and the main transport to the stream is expected to take place as drift into a more or less well defined amount of water. Considerable work has gone into the design of a suitable user interface including data input and extraction of data relevant for evaluation of effects.