The site is situated in lowlands of Central Poland and arranged around the Sulejowki Reservoir. It has been build in 1969-1974 on the Pilica River mainly as a source of drinking water for the City of Lodz (the third biggest city in Poland) and other cities like Tomaszow, Piotrkow, Sulejow, and a power generator. With time it became also an important touristic and recreational place.
The research area includes the reservoir and its direct catchment, where smaller plots have been located for analysing surface flow, groundwaters, and the role of land/water ecotones in regulation of nutrient cycling. There is number of sampling sites/points located also on the reservoir, 3 of them are permanent since 1980's and serve as a source of data on water chemistry, the others are sampled periodically for certain purposes, e.g. fish (including 1+), phytoplankton, zooplankton, sediment depositon, groundwater level, groundwater chemistry.