In reverse system of water supply accepted at Beryozovskaya SDPS- 1 the bulk of exhaust waters moves around the most part of this weight repeat-edly passes through cooling systems condensers. Continuous monitoring is not only thermal and still hydrochemical and sanitary and biological mode of the reservoir is necessary for ensuring effective work of thermal power plant in the period of con-struction and consecutive connection to generation of three blocks of thermal power plant. Water pollu-tion connected with thermal dumping causes the violation of normal work of the heat power equip-ment, i.e. there is reduction of sections through passage of condensers tubes. It leads to the in-creasing in temperature pressure and of the coeffi-cient of heat transfer of tubes conducting to big burnout of fuel, finally - to the decrease in econom-ic indicators of work of state district power station. The research objective was the detection of fea-tures of formation of thermal mode of reservoir cooler of BSDPS -1 for the assessment and fore-cast of water quality and also adjustment of rated capacity of state district power station - the number of power units put in the project. It is defined that the formation of circulating stream of made winter-proof water takes place under the influence of the following three factors: narrowing of the stream at the expense of created congestion of weighed and segmented particles at the exit from waste channel; interactions of the stream of made winter-proof wa-ter from waste channel and the stream of river wa-ter passing on the reservoir bottom around dump-ing; the impact of prevailing winds having opposite direction. The recommendations on overcoming these factors are offered. Morphometric features of the structure of the reservoir, hydroweather condi-tions and thermal dumping promoted creation of conditions for the existence of "biofund" of blos-soming, realization of conditions for a reservoir cooler eutrophication. The increase of average an-nual water temperature has already led to "thermal" eutrophication of a reservoir cooler of BSDPS-1 during the initial period of existence.