IRKUTSK, April 4. /TASS/. The water level in Lake Baikal, the world’s largest freshwater body, continued decreasing in early April to fall below the critical level of 456 meters defined under the Pacific Elevation System, according to data posted on the website of Russia’s Federal Agency for Water Resources on Monday.
Lake Baikal’s water level is now 26 cm below its minimum required mark, the data suggest.
"As of April 1, the water level in Lake Baikal is 455.74 meters above the Pacific Ocean," the Federal Agency for Water Resources said.
Forecasts suggested earlier that the water level in Lake Baikal might drop by 30 cm by late April. However, the pace of the water level decrease in the past few weeks suggests that the 455.74-meter critical level may fall even further.
According to the data of the Federal Agency for Water Resources, average daily water discharges through the Irkutsk Hydropower Plant, which makes up the Irkutsk reservoir together with Lake Baikal, remain at the level of 1,300 cubic meters per second. However, under the existing legislation, water discharges through the Irkutsk hydropower system are prohibited in such volumes when the water level in Lake Baikal falls below the critical level.
The Russian government has been issuing a temporary resolution for the second consecutive year for the critical period to keep normal water supply for the population and enterprises in the lower reach of the Angara River that drains Lake Baikal.
"Owing to a change in the ice situation and the decrease in the water level at water intake facilities in the downstream reach of the Irkutsk HPP and proceeding from the need to prevent water supply interruptions, a mode of operation has been established for the Irkutsk HPP since March 16, 2016 with daily water discharges of 1,300 cubic meters per second," the agency said.
As TASS reported earlier, the Russian government plans to expand the range of the minimal and maximal marks of the water level in Lake Baikal. A draft new document is now under public discussion.
Under the new draft, the minimal and maximum marks will be set at 456 and 457 meters during medium water content periods. At the same time, the lower mark will be established at 455.54 meters during the low water content period while the higher mark of 457.85 meters will be set during the high water period.
The explanatory note to the draft government resolution says that the minimum mark parameter will help ensure stable thermal power and water supply for households and industrial facilities in the downstream reach of the Irkutsk HPP during the low water content period. At the same time, the mark of 457.85 m will correspond to the statutory threshold level of safety at industrial and hydropower facilities during the high water period.
Last year, the lowest critical mark in Lake Baikal’s water level was registered at 455.86 meters, i.e. 14 cm below the norm. This level was registered on April 26 and it returned to the permissible levels by June 5.
According to Russia’s Weather Forecasting Center, the water fill rate of Lake Baikal may range between 40% and 95% this year.
Experts say that Lake Baikal has entered a new period of naturally low water levels, which was observed before and may last a quarter of a century.
Since 1962, the water level of Lake Baikal has been observed to drop below the 456-meter mark 11 times. In particular, the record low mark of 455.27 meters was registered in 1982.
Lake Baikal in south-east Siberia, the deepest lake in the world at 1,700 m, contains 20% of all fresh running water on the planet, making it the single largest reservoir. The lake contains an outstanding variety of endemic flora and fauna, of exceptional value to evolutionary science.
It is also surrounded by a system of protected areas that have high scenic and other natural values. The basin supports a variety of plant and animal species, a number being endemic; the most notable of which is the Baikal seal, a uniquely freshwater species. The great variety of plants in the basin is determined by its climatic asymmetry: the western part is occupied by light coniferous forests and mountain steppes; in the eastern part pine forests predominate; and the north is covered by deciduous forests.
The formation of the geological structures in the basin took place during the Palaeozoic, Mesozoic and Cenozoic eras and there are a number of significant geological features. Various tectonic forces are still ongoing, as evidenced in recent thermal vents in the depths of the lake.
The lake itself is the centerpiece of the site and its largely unseen underwater features are the core of its value to both science and conservation. Baikal is one of the most biodiverse lakes on Earth, with 1,340 species of animal (745 endemic) and 570 species of plant (150 endemic).
In the forests surrounding the lake there are an additional 10 threatened species along with the full complement of typical boreal species. The evolution of aquatic life that has taken place over this long period has resulted in an exceptionally unique and endemic fauna and flora. As the 'Galapagos of Russia', the lake is of exceptional value to evolutionary science.