Studies of surface waters were carried out in a suburban catchment of the Sudół Dominikański stream where a small storage reservoir is to be built. Water for analyses was ampled from the gauging section situated on the main watercourse immediately below the dam of the projected reservoir, at 14 dates in the period of July 2005 to February 2007. Additionally, at one date the quality of water was examined at six other points located on the main watercourse and its tributary. Standard methods were used to determine 18 physicochemical properties, including 16 quality indices, of water at each measuring-and-control point. The results revealed that the degradation of water is far advanced in the dam section of the planned reservoir. The water contains high concentrations of phosphates and of ammonium and nitrite nitrogen forms. The inflow of treated sewage from the local treatment plant constitutes the main source of pollution. The current level of water pollution in the stream poses a threat of eutrophication to the future reservoir.

3-14