Assessment of runoff nitrogen load reduction measures for agricultural catchments

Water quality in rural catchments is influenced by many societal and bio-physical factors (e.g. different pollution sources, land use and land cover changes). Good ecological status and surface water quality are currently challenged mainly due to different poorly identified pollution sources. The main objective of this study is to estimate the potential of different measures (land use changes and/or reduction in point sources) and their combinations in decreasing the nitrate-nitrogen load from Jankovsky stream catchment. The eco-hydrological model SWIM, which simulates dynamics of nutrients in a catchment was used in the study. The simulations for scenario measures showed that nitrate-nitrogen loads at the outlet can be decreased more by reduction of municipal nitrate-nitrogen sources rather than by agricultural land-use change. Overall, the modeling results demonstrated that the most effective scenario was the combination of total reduction of municipal nitrate-nitrogen sources and agricultural land-use change.