Planning and implementation of nitrogen reduction measures in catchment areas based on a determination and ranking of target areas

In this paper the application of the integrated hydrological/hydrogeological conceptual model for geographical prioritization and determination of environmental target areas in the case study area Große Aue in the Federal State of Lower Saxony, Germany is described and discussed. It is demonstrated how area differentiated parameters like the denitrification condition in soils, the runoff ratio, nitrate concentrations in the leachate and groundwater monitoring data are determined and combined in order to determine target areas. With the given example of the case study area Grosse Aue, the importance of defining the receptor of nitrate outputs (groundwater or surface water) and the environmental target prior to the delineation of environmental target areas could be shown.