In the province of Overijssel, Netherlands, groundwater is the only source of drinking water. The province is responsible its protection and management. Land use consists of agricultural land (mainly dairy farming with 80% grass and 20% maize), natural and some urban areas. The sources of contamination are from nitrate and pesticide leaching through the shallow sandy soil into the groundwater.
Since 2011, the province of Overijssel and the Vitens drinking water company, together with Wageningen University, Countus, Stimuland and Royal HaskoningDHV have given support to dairy farmers to improve their mineral management in the recharge areas of five vulnerable drinking water abstractions through the project Farmers for Drinking Water (»Boeren voor Drinkwater).
Objectives are to achieve:
- 50 mg NO3/l in the upper phreatic groundwater below agricultural area;
- 0.1 µg/l pesticides in the upper phreatic groundwater below agricultural area.
Targets for agricultural management are:
- N-soil surplus of at most 100 kg N/ha calculated by the Annual Nutrient Cycle Assessment (ANCA);
- a maximum 100 Environmental Impact Points (EIP) of individual pesticides and max 500 EIP for the total of all pesticides used.