Transformation of the flow of matter in valley reservoirs as a factor of improving their ecological condition

Abstract

The results of perennial studies of the valley reservoirs of the Moskva River (Mozhaysk, Ruza and Ozerna reservoirs) have shown that the influx of river waters bringing nutrients leads to eutrophication of the upper parts of the reservoirs. However, as water moves, this matter is extracted by phytoplankton and zooplankton and undergoes sedimentation. The content of the suspended materials, iron, true colour of water near the dam are two times lower than in the upper reaches of the reservoirs; the concentration of mineral silicon and phosphorus decreases by nearly one-fourth, and that of organic matter, by 10-15%. As a result, in the near-dam zones of the water reservoirs biological productivity decreases: the biomass of phytoplankton and bacteria in water decreases by nearly 40%. Thus, transformation of the flow of matter along the length of the valley reservoirs results in essential improvement of the quality of water and reduction of the degree of eutrophication, which is especially important for the reservoirs which serve as sources of water supply for the city of Moscow.