Spatial and temporal analyses of catchment and in stream nitrate dynamics : insights derived from fully distributed process based modeling and high frequency monitoring Water quality in river systems is of growing concern due to rising anthropogenic pressures and climate change. Mitigation efforts have been placed under the guidelines of different governance conventions during last decades (e.g. the Water Framework Directive in Europe). Despite significant improvement through relatively straightforward measures the environmental status has likely reached a plateau. A higher spatiotemporal accuracy of catchment nitrate modeling is therefore needed to identify critical source areas of diffuse nutrient pollution (especially for nitrate) and to further guide implementation of spatially differentiated cost effective mitigation measures. On the other hand the emerging high frequency sensor monitoring upgrades the monitoring resolution to the time scales of biogeochemical processes and enables more flexible monitoring deployments under varying conditions. The newly available information offers new prospects in understanding nitrate spatiotemporal dynamics. Formulating such advanced process ...