Assessment of the impacts of preventive strategies for ground water protection in the agricultural sector

The Office of Technology Assessment of the German Bundestag concluded at the beginning of 1994 its technology assessment to the topic "Ground Water Protection and Water Supply". This article aims to present the approach and results of the part". Quantitative Analysis of Preventive Strategies for Ground Water Protection in the Agricultural Sector". The impacts of a regionally differentiated ground water protection strategy and a blanket-coverage ground water protection strategy - the latter subdivided in two avariants ( reduction of the intensity of land utilisation everywhere and locally specified reduction of the land utilisation intensity) - were investigated. Using the "Regionalised Agricultural and Environmental Information System" (RAUMIS) ground water relevant indicators (nitrogen surplus, use of pesticides) and agricultural policy relevant indicators (factor utilisation, production, income) were determined on the country level of the old Bundeslaender for the ex- post-analysis and for the simulation year 2005. For the new Bundeslaender only a less differentiated analysis could be carried out. Using the regional nitrogen surplus and the regional use of pesticides with ground water restrictions BUeTOW und HOMANN (1992) estimated the potential medium nitrogen and pesticide concentration in the surface near ground water and the hereby caused cost of the water supply industry in the case of constant ground and spring water extraction. As reference point for the monetary assessment of the total ground water contamination, with the ground water utilised for drinking water being just a part of it, fictitious costs for the processing of the total surface near ground water were roughly estimated. The model calculations show, that the preventive strategies can contribute to the reduction of potential risks to