The Pilica River watershed is located in central Poland (length:342 km, catchment area: 9258km2). Its mean and maximum discharge is 21.2 and 139m3 s−1, respectively. Agriculture is found in over 60% of the Pilica catchment, and results in an increased supply of nutrients, humic substances, and other pollutants from non-point sources to the river and the Sulejow Reservoir, which is a spare drinking-water reservoir for the Lodz agglomeration and a recreational area. The LTER site includes the experimental floodplain of the Pilica River valley (51°18'58.46''N and 19°54'10.54''E), located in the middle reach of the river, upstream of the reservoir.