Kolyma Hydroelectric Power Plant Impact on Floodplain Ecosistems of the Seimchan Part of the Magadansky National Reserve
The long-term course of maximum levels of rivers within upper Kolyma drainage and change of the areas of different parts of floodplain in Seymchan part of the national reserve after end of HPP construction is studied. It is shown that the close contribution in reduction of these levels was brought by intercepting of spring flood by reservoir and by long-term course of water levels over upper Kolyma drainage. Their total impact is about 90 sm. The area of low floodplain in the Seimchan part of the reserve has reduced from 33 to 10% of a total area of islands between 1990 and 2010. The last number is similar to the one for the Kolyma floodplain above the reservoir backwater zone. Wide expansion of chozenia communities on this control polygon permits to believe that in the Seimchan part of the reserve any essential change of vegetation does not occur under a modern operative mode of the HPP In case of the HPP operating in the designed mode, the Kolyma level impact on the floodplain relief and the transformation of the floodplain vegetation would not be significant, unlike the consequences of the talik area reduction.