Potential impact of climate change on nitrate load from the Jizera catchment (Czech Republic)

Water quality modeling was done in order to evaluate possible impact of climate change on water quality in the Jizera catchment regarding nitrate pollution. The research was performed by using the eco-hydrological model SWIM (Soil and Water Integrated Model), which simulates water and nutrient fluxes in soil and vegetation, as well as transport of water and nutrients to and within the river network. The modeling period was from 1981 to 2001. After the calibration of hydrological processes in the catchment, water quality (nitrate) modeling was carried out. The emissions from point sources and agricultural diffuse sources were taken into account. The influence of climate change on water quality in the Jizera catchment was assessed by using the outputs of two approaches to regional climate modeling: dynamical (REMO) and statistical (STAR). The two approaches projected different future discharge and nitrate nitrogen loads in the Jizera catchment. rojected increased discharges and nitrate loads in winter consequently with projected increased precipitation. The nitrate loads in summer are influenced mainly by changes in precipitation. The statistical approach STAR projected decreased nitrate loads because of decreased precipitation. More intensive rain causes increased load mainly in summer and increased temperature in winter contributes to increased discharge.