ИСТИНА

Mozhaysk reservoir is a medium-size (30.7 sq km) valley reservoir located in central European part of Russia. It was filled in 1960–1962 and has average depth of 7.7 m, maximum depth of 22.6 m and retention time of about 180 days. Mozhaysk reservoir has features of a typical temperate dimictic lake with stable thermal stratification forming during summer and winter. It can be classified as eutrophic with algal blooms occuring once every 3-5 years. Krasnovidovo limnological station of Lomonosov Moscow State University is serving as a site of long-term monitoring of Moscow region reservoirs, primarily the Mozhaysk reservoir. The station began operation in 1965 and now has collected more than 50 years of observation data, composed mostly of physical parameters in the beginning with focus shifting to biological and chemical characteristics in 1980s. The list of regular monitoring parameters now includes Secchi depth, water temperature, conductivity, dissolved oxygen content, pH, major ions, total and mineral phosphorus and silicon content, organic matter content indices (true water color, COD, Permanganate index), chlorophyll concentrations. Meteorological data is available for Mozhaysk city located 15 km from station. Full set of parameters is measured annually in the beginning and end of summer at 19 stations during hydrological surveys, and in some years additional surveys are conducted once per month. More frequent data on Secchi depth and vertical distribution of water temperature, conductivity and dissolved oxygen are available for a buoy station, with automatic temperature sensors data covering all ice-free periods since 2015.