Raw water quality prognosis

Nitrate pollution of groundwater due to excessive application of fertilizers and manure in agriculture is an increasing problem in many countries and displays a major threat to drinking water supply. Ensuring future drinking water supply requires a sustainable management of water resources regarding both quantity and quality. As illustrated by the case study of the Rasseln Waterworks (Moenchengladbach, Germany) a reactive transport model has been developed. The model calculates the development of ground- and raw water quality for each of the three aquifers used for drinking water production under consideration of all relevant hydrogeochemical and geo-hydraulic processes as well as temporal changes in fertilizer and manure application on arable land. Monitored trends in raw water quality can be retraced retrospectively. For predefi ned scenarios of nitrate input long-term forecasts of raw water quality are calculated. Thus, this model is an appropriate tool to test the effi ciency of agricultural measures on raw water quality development.