LAKE ILMEN General description Watershed area -66,400sq.km Water surface area -1,120 sq.km (660 -2,230sq.km) Storage – 12 cub.km Mean depth at mean level. - презентация

1 LAKE ILMEN

2 General description Watershed area -66,400sq.km Water surface area -1,120 sq.km (660 -2,230sq.km) Storage – 12 cub.km Mean depth at mean level – 2.6 m Maximum depth at mean level m Lake height – 18msl Watershed height– msl Inflowing rivers -50 (Lovat, Msta and Shelon – 82,5% of the watershed area) Outflowing river –Volkhov

3 The Volkhov hydropower plant Constructed in (26.5 km from the River Volkhov mouth – total length of the R.Volkhov km) Constructed in (26.5 km from the River Volkhov mouth – total length of the R.Volkhov km) Daily and weekly regulatation Daily and weekly regulatation Storage - 0,037 cub.km Storage - 0,037 cub.km Power capacity- 66,000KWt Power capacity- 66,000KWt

4 Lakes llmen level regime

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7 Water balance The income and outcome parts of the Lakes Ilmen water balance is equal to 15 cub.km per year. Residence time -1 month The income and outcome parts of the Lakes Ilmen water balance is equal to 15 cub.km per year. Residence time -1 month

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9 Lakes Ilmen thermal regime

10 Duration, days warming from 4 to 10C (Spring) «biological summer» >10Ccooling from 10 to 4C (Autumn)

11 The Lakes water heating more than 25C is one of the most unfavourable factors for biota that provokes the lack of oxigen in water, Summer fish dealth and waterblooming. Last 3 decades in comparison with earlier period are rather favourable as the growth of water temperature higher than 25C has been observed only in 55% of years – earlier in 80%. The growth of mean annual air temperature is mainly due to the growth of winter temperature and is not clearly obvious in the thermal regime of Lake Ilmen

12 Lakes Ilmen ice regime

13 Trend in maximum ice thickness

14 THANK YOU