A study on the chemism of precipitation and the migration of biogens was carried out in the Masurian Lakeland in 14 agricultural and forest catchment basins. The purpose of this study was to determine the supply of chemical components together with precipitation into the soil and the degree of threat to water ecosystems as a result of transfer of biogens from catchment basins to open water systems and subsoil moisture. Moreover, a model of precipitation catcher, which enabled such studies was presented.