The article contain data on analyzed the long-term dynamics of the spatial structure of vegetation lake Kenon, more than 50 years, used as a coolant reservoir Chita Thermal Power Station – 1. Shown that the main lakes are the dominant charophyta vegetation, an important stabilizing element of the reservoir ecosystem. The greatest influence on the vegetation of the lake was put in 70 years, due to invasion of vegetable-feeder fish. In the eighties of the year there was a change in the composition of the dominant communities’ amphibious plant, currently missing in the lake zone of plants with floating leaves. On the whole ecosystem of the lake Kenon can be described as an alternative stable state, with alarming exceedance for some heavy metals. Forecast period, increasing moisture Transbaikal region, adversely affect the membrane of chara algae communities and can cause negative rearrangements in the lake ecosystem Kenon.