Ecological state and new approaches to the restoration of lake Uvildy, Russia

Abstract

Lake Uvildy is situated in the North of Chelyabinsk region. Lake Uvildy is one of the largest and the most unique of South Ural's lakes. In 1975-1977 the drought occurred and water supplies dried up in South Ural. 234 million cubic meters were moved from the Uvildy lake in Argazi reservoir, which was a source of water supply of the Chelyabinsk city. The lake's water level fell by more than 4 meters. Only in 2008 the water level returned to the previous position, but riparian vegetation was flooded. In July 2014 we carried out an ecological survey of the lake in five sites. We discovered submerged tree and shrub vegetation at 50-70 meters from the bank. Chemical analysis of water revealed the accumulation of organic substances and the transition of nitrogen from nitrate to nitrite and ammonia, of sulfur from sulfate to sulfite and hydrogen sulphide, of carbon to methane. We found blue-green algae (Microcystis, Anabaena, Oscillatoria) in all the sites. It indicates the beginning of water eutrophication. We proposed a new method of ecological restoration of the lake. In August 2014 we cleaned the bottom of the lake in two research points with a special innovative bottom-cleaning machine working both as a pump and a crusher. The research in summer 2015 showed that the water quality had significantly improved and the process of eutrophication had stopped in the points where the bottom was cleaned. Works on the lake trophicity will be continued.