Medeu Dam
Encyclopedia
Medeu Mudflow Control Dam is a dam across the Medeu Valley south-east of Almaty
, Kazakhstan, designed to protect the city from devastating debris flows (or mudflow
s).
is built on the alluvial fan
of the Malaya Almatinka River, at the point where the river leaves the steep and narrow Medeu Valley for the wider plain. The river valley, steeply descending to the city from the Trans-Ili Alatau
mountains, is highly susceptible to the formation of debris flows and/or mudflows. During the 20th century, five catastrophic debris/mudflows happened in the valleys of Malaya Almatinka, or its sister river (further west), Bolshaya Almatinka. The most severe of them was the catastrophic mudflow of 1921 in the Malaya Almatinka valley, triggered by heavy rainfall. It killed 500 people out of Almaty's 45,000 population at the time, and destroyed much of the city. The total volume of that flow is thought to have been 10 million cubic meters (including some 3 million cubic meters of hard material, i.e. rock), coming down to the city at the discharge rate of 900 cubic meters per second. It is estimated that if a repetition of the 1921 mudflow were to strike the city in the early 21st century, the damage would be on the order of US $100 million.
To prevent mudflows from reaching the city, a number of facilities have been built upstream of the city on both the Bolshaya (Greater) and Malaya (Lesser) Almatinka Rivers.
It was created on October 21, 1966 by a series of four preliminary explosions of 1,800 tons total and a final explosion of 3600 tons of ammonium nitrate based explosive. On April 14, 1967 the dam was reinforced by an explosion of 3900 tons of ammonium nitrate based explosive. More filling was done later on, until the dam reached its design profile in 1972.
Mikhail Lavrentyev
, the Siberian
mathematician known for his work on the theory of "directed explosion", was among the scientific consultants of this construction-by-explosion project.
It turned out that the dam was completed just in time for the potentially catastrophic mudflow of July 15, 1973. The dam worked, successfully stopping the flow. 3.8 million cubic meters of sediment was captured in the reservoir above the dam, bringing its bottom to the elevation of 1835 meters above the sea level.
43.1505656°N 77.0626116°W
Almaty
Almaty , also known by its former names Verny and Alma-Ata , is the former capital of Kazakhstan and the nation's largest city, with a population of 1,348,500...
, Kazakhstan, designed to protect the city from devastating debris flows (or mudflow
Mudflow
A mudslide is the most rapid and fluid type of downhill mass wasting. It is a rapid movement of a large mass of mud formed from loose soil and water. Similar terms are mudflow, mud stream, debris flow A mudslide is the most rapid (up to 80 km/h, or 50 mph) and fluid type of downhill mass...
s).
The mudflow threat
Much of downtown AlmatyAlmaty
Almaty , also known by its former names Verny and Alma-Ata , is the former capital of Kazakhstan and the nation's largest city, with a population of 1,348,500...
is built on the alluvial fan
Alluvial fan
An alluvial fan is a fan-shaped deposit formed where a fast flowing stream flattens, slows, and spreads typically at the exit of a canyon onto a flatter plain. A convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial...
of the Malaya Almatinka River, at the point where the river leaves the steep and narrow Medeu Valley for the wider plain. The river valley, steeply descending to the city from the Trans-Ili Alatau
Trans-Ili Alatau
Trans-Ili Alatau , , also spelt as Zailiyski Alatau, Zailiysk Alatau, etc., is a part of the Northern Tian Shan mountain system in Kazakhstan and Kyrgyzstan. It is the northernmost mountain range of Tian Shan stretching for about 350 km with maximal elevation of 4,973m . The term "Alatau" refers...
mountains, is highly susceptible to the formation of debris flows and/or mudflows. During the 20th century, five catastrophic debris/mudflows happened in the valleys of Malaya Almatinka, or its sister river (further west), Bolshaya Almatinka. The most severe of them was the catastrophic mudflow of 1921 in the Malaya Almatinka valley, triggered by heavy rainfall. It killed 500 people out of Almaty's 45,000 population at the time, and destroyed much of the city. The total volume of that flow is thought to have been 10 million cubic meters (including some 3 million cubic meters of hard material, i.e. rock), coming down to the city at the discharge rate of 900 cubic meters per second. It is estimated that if a repetition of the 1921 mudflow were to strike the city in the early 21st century, the damage would be on the order of US $100 million.
To prevent mudflows from reaching the city, a number of facilities have been built upstream of the city on both the Bolshaya (Greater) and Malaya (Lesser) Almatinka Rivers.
Dam history
Medeu Dam blocks the Medeu Valley (the valley of the Malaya Almatinka River) just south (upstream) of the Medeu Skating Rink.It was created on October 21, 1966 by a series of four preliminary explosions of 1,800 tons total and a final explosion of 3600 tons of ammonium nitrate based explosive. On April 14, 1967 the dam was reinforced by an explosion of 3900 tons of ammonium nitrate based explosive. More filling was done later on, until the dam reached its design profile in 1972.
Mikhail Lavrentyev
Mikhail Lavrentyev
Mikhail Alekseevich Lavrentyev or Lavrentiev was an outstanding Soviet mathematician and hydrodynamicist.-Biography:...
, the Siberian
Akademgorodok
Akademgorodok , is a part of the Russian city Novosibirsk, located 20 km south of the city center. It is the educational and scientific centre of Siberia...
mathematician known for his work on the theory of "directed explosion", was among the scientific consultants of this construction-by-explosion project.
It turned out that the dam was completed just in time for the potentially catastrophic mudflow of July 15, 1973. The dam worked, successfully stopping the flow. 3.8 million cubic meters of sediment was captured in the reservoir above the dam, bringing its bottom to the elevation of 1835 meters above the sea level.
Literature
- Ts.E. Mirtshoulava, "Mud floods in the Caucasus and Central Asia", in "Floods", ed. Dennis J Parker, pp. 217-218. ISBN 0415227437. Full text available on Google Books.
43.1505656°N 77.0626116°W