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.

Theories about the evolution of information in time have begun to be used systematically and repeatedly by communities of scholars to fruitfully generate new knowledge about the past only in 1780, first in German faculties of Protestant theology, among classical linguists and then around the turn of the 19th century in comparative linguistics. Ranke used such theories in the second quarter of the 19th century to generate knowledge of history, and then similar methods spread to biology, geology and archaeology.