ИСТИНА

As a result of experimental calculations for some polytypic reservoirs in the European territory of Russia their hydrological regime will probably change at implementation of the most adverse forecasts of drain reduction. The following changes are expected: increase of intra annual amplitude of water surface temperature, increase in duration of the period of open water, reduction of water inflow in reservoirs and reduction of their flowage, increase of summer stratification duration, deterioration of the oxygen regime in summer and improvement in winter. Change of the hydrological regime can entail ambiguous changes of biological processes. Reduction of level amplitude fluctuations is favorable for water plants growth reducing phosphoric load on the reservoir. However the general lowering of the level in the conditions of underfilling to normal gorizont can reduce this factor at the expense of increase in exchange of phosphorus with ground deposits at reduction of depth. At decrease in level of filling warming up of benthonic layers can cause earlier approach of a phase of blue-green algae cages emersion. At shift of terms of hydrological regime phases it is possible to expect more earlier approach of algae development phases. Results of modeling showed that the strong overheat of water bodies at climatic changes shouldn't be expected. The initial level and weather conditions during stratification forming are very important. Also upwellings and deep mixing during cold periods in summer are important for taking out of food supply to a surface from a benthonic layer, t.e. whether synoptic fluctuations of meteorological characteristics will increase.