The study analyses long-term and seasonal changes in the water regime elements and water balance components of the Upper-Svir Reservoir, including inflow, runoff and fluctuations in water level of Lake Onego over the whole observation period. It is shown that currently there is an increase in the frequency and duration of high levels of Lake Onego. The impact of climate changes and HPP operation on lake level rise has been assessed. Science-based recommendations to optimize the operating mode of the Upper-Svir Reservoir, aimed to reduce the level of Lake Onego, have been developed.

No abstract