TY - JOUR N2 - In the period from March to October 1998 hydrochemical researches on a dam-reservoir Przeczyce were carried out. This resevoir is an effect of the partition of Czarna Przemsza valley, by ground barrier. Surface area of the reservoir is 570 ha, and its total cubic content is 20.75 mln m3 of water. Researches proved that in effect of systematic conveyance of pollutans by the Czarna Przemsza River, water quality in the reservoir is in eutrophy state. Raised concentration of orto-phosphates in output originating from washing out of drainage basin soils (the Schindler coefficient is 64), and from domestic sewage causes, notwithstanding relatively low concentration of nitrates, a threat for the reservoir. Disadvantageous nitrogen-phosphorus proportion, which amounts 56 od a tributary stream, 20 in the reservoir, and 14 in a autflow, is conducive to eutrophication of the reservoir. This proportion indicates that in Przeczyce dam-reservoir phosphorus is the agent limiting use of nitrogen in the process of primary production. Balance of nitrogen and phosphorus, and especially that a load of phosphates leaded to the reservoir counterbalances itself with a load of water diversion. This evidences the loss of the reservoir ability to lay surplus nutrients, especially phosphorus, in bottom sediments, and consequentlyattests to the near moment of starting the process of anrichment from the inside of ecosystem. In the next, last part of this paper, results hydrobiologically (macrobentos) investigations will describe. L1 - http://journals.pan.pl/Content/124211/PDF/9_AE_VOL_26_3_2000_Derylo_Badania.pdf L2 - http://journals.pan.pl/Content/124211 PY - 2000 IS - No 3 EP - 87 KW - hydrochemistry KW - selfpurification KW - water protection KW - dam-reservoirs A1 - DeryƂo, Antoni A1 - Kostecki, Maciej A1 - Szilman, Piotr PB - Polish Academy of Sciences VL - vol. 26 DA - 04.09.2022 T1 - The Hydrobiological Researches of Przeczyce Dam-Reservoir (Czarna Przemsza River). Part I. Hydrochemical Factors of Water Quality SP - 67 UR - http://journals.pan.pl/dlibra/publication/edition/124211 T2 - Archives of Environmental Protection ER -