THE FLOOD: TAKE TWO FEATURING THE SAYANO-SHUSHENSKAYA POWER STATION

A water mill is the oldest way of producing electricity. The method reached a climax at the industrial age which employed thousands of hydroelectric power stations. Russia may be proud of Eurasias most powerful and highest power station, the Sayano-Shushenskaya power station built on the Yenisei. The power station is 240 m high and more than a kilometer wide. The power stations first unit was put into operation in 1978; the facility became fully operational three years ago. The annual output is 25 billion kW/h i.e. about 3% of all power produced by Russia. The design defects were first found in 1981. Those defects could have lead to destruction of the power station and a large-scale accident in the history of water power. They had to be fixed while running the complex facility. This year has seen the final approval of a plan to build a spillway on the river bank. A detail design of the project is to be finalized in mid 2004, the construction is to commence on January 1st, 2005.

All the peoples have their own legends of the Flood that ruined humanity in prehistoric times. The climatology experts believe the legends are based on real floods that occurred in the history of the world. A great number of floods killing thousands of people entered the historical records of the civilization. The damage done by floods becomes increasingly greater as man-made activities intensify. The damage due to accidents on hydroelectric power stations dams has the most devastating impact. The water flow of the Yenisei nearly equals that of all the rivers in the European part of Russia; its 2.5 times greater than the water flow of the Volga. Some can say that an accident on the Sayano-Shushenskaya power station will trigger a new flood of the Biblical proportions.

Enough with those frightful pictures. Heres some basic data for your consideration:
the flow capacity of the Sayano-Shushenskaya power station is 13.5 thousand m3/s; the water level in the Yenisei increased at 2-4 thousand m3/s at the time of a flood in the last few years. The water level increased at 10 thousand m3/s during the record floods of 1916, 1936, 1966. Since the facility went into operation in 1979, the highest water level increase was recorded in 1979 – 7 thousand m3/ s. In other words, therere certain guarantees in case of most terrifying natural disasters.

Vladimir Lenin once coined the formula of communism. According to him, its the Soviet power plus the electrification of the whole country. It seems ironic that the young Lenin had been sent into exile to the village of Shushenskoe, though the issue of electrification hardly concerned him at the time. He spent most of his time shooting hares and waiting for his wife to arrive. Its obvious to me that the place is charged with some peculiar kind of electricity. Shushenskoe brought inspiration into Lenin, he stirred up the electrification plan that centered on a hydroelectric power station in Shushenskoe. However, the facility is named after Peytr Neporozhni who was the Energy Minister for 25 years regarded as the most successful period in history of the Soviet power sector.
The total area of the facility is 621 km3, its holding capacity is 31.3 km3. The speed of water falling down the spillway to the dam base is 54 m/s. The design proved to be rather faulty for a number of reasons. The concrete toe basin cant hold the water head therefore the divides and aprons are subjected to deterioration. The defects of the dams foundation bed tend to spread all over the dam structure. Thousands of people live in areas lying down the river. The capital of Khakassia is located in the vicinity.

The toe basin has a sad history. 75% of its concrete blocks were destroyed by the 1985 spring flood. Another large-scale flood that swept across the area in 1988 damaged the toe basin that had been just repaired. A decision was taken to switch the operations into a light-duty mode with 540 m of the water level limit in lieu of 545 m water level as by design.

The research council was set up for conducting a systematic monitoring of the power plant in 1996. It was headed by Semen Laschenov, a renowned construction engineer who supervised the construction of a complex hydropower station in Nurek, Tadjikistan. Specialists from all the hydraulic research institutes of Russia took part in the job. As a result, experts recommended to build another tunnel spillway to reduce the dynamic impact of the flow on the dam foundation. A new spillway could take from 4 to 5 thousand m3/s of the water. But the construction was never started due to lack of funds. The money was only allocated to fill the cracks in the concrete structure with cement and new composite materials. The cracks were finally filled in after a long period of repairs.

Speaking to Izvestia, Semen Laschenov said that the new discharge tunnel would cut down the spillway by a third thus providing a super-guarantee to the dam safety. Safety isnt an empiric notion, its based on complex calculations of a hydraulic power system and must be in compliance with the international standards for hydropower facilities. The standards are getting tougher due to recent catastrophic floods in various parts of the world. For example, the EU has recently ordered a revision of the water flow characteristics of a cascade of the Daugava hydroelectric power station in Latvia.

Ledgidroproekt, a research institute based in St. Petersburg, produced a design of the shore spillway comprising 2 tunnels of 1,100m each. The project will involve large-scale operations with 3,500 m3 of soil to be removed and some 100 m3 of concrete to be used underground. The tests involving a complete simulation of real conditions were conducted at the laboratories of the Construction Research Institute of Power Facilities.
Absorbing the energy of the falling water is the hardest task. The tunnels unique design resembles a staircase, it includes four intricate dampers to slow down the water flow.

The detail design of the shore spillway is to be approved in summer of 2004. If the project goes under way according to plan, the construction is going to kick off on
January 1, 2006. Its estimated to be completed in 6 years. The power station will be capable of letting through the most devastating flood after the completion of the project. The terrible flood in question is thought to occur once per 10,000 years.

A hundred years ago, the young Lenin used an oar for killing the hares who were flocking on the dry islets looking for shelter during the flood. Lets hope those poor creatures remain the last victims of the local flooding waters. Lets hope that the project on the Sayano-Shushenskaya hydropower station will be a success.

Reference Data

From 11 to 15 large-scale accidents on the dams occur worldwide each year. The largest one happened in 1933 on the Huang He river in China, 18 thousand people were killed. The Chinese used the killing power of the Huang He against the advancing Japanese armies on the same year. They tried to divert its waters into a different channel. The Japanese armies were stopped but another half a million people died in the process.

In 1963, 2 thousand people got killed within 15 minutes when the dam broke loose in Vaionte, Italy. The damage of the levee by a flood resulted in 2 thousand deaths in India in 1972. 13 people died when a flood washed away the dam near a Swiss town of Gondau in 2000. The Vysla broke through 5 dams in Poland in 2001, 12 thousand people had to be evacuated. A few dozen were killed by the 2002 flood in Mexico. On the same year 7 dams burst on the Elba in Germany flooding a number of nearby villages and towns. Last year another killer flood happened in China, in Xansi province, 72 people were killed and 50 thousand houses destroyed.

Russias worst accident took place in 1994, in Bashkiria. The dam on the Tirlyanskoe reservoir burst and flooded 4 villages. 29 people were killed and 200 houses were destroyed.

.. - NEKTO 2009.


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