Widely known as a potential environmental hazard often referred to as a "time-bomb" or the "Sleeping Dragon of Pamir", ote Sarez Lake represents risk associated with the unexpected dam burst and flooding vast area of densely populated Panj and Amu Darya valleys.
A concern is growing over Lake Sarez, a lake in Tajiskistan that threatens to flood parts of four Central Asian countries, namely, Tajikistan, Afghanistan, Uzbekistan, and Turkmenistan. The lake is located at 3265 meters in the earthquake-prone Pamir mountain range (see the map attached) which can be characterized by one of the highest seismical region in the world. It forms an unstable natural dam on its shores. Because of the lake's high altitude, an earthquake or major dam break could rapidly unleash unprecedent ed , catastrophic floods across the four countries, with a speed and a force that would destroy everything in its path. In accordance with the data of the Institute of Seismicity and Seismoresistant construction of Tajik Academy of Sceinces such earthquake c ould create a wave of 30 meters high that will cover 52 million square kilometers in the four countries, where 5 million people presently live.
Lake Sarez was created on February 5, 1911, as a result of a powerful earthquake which registered 6.5 to 7.0 on the Richter Scale. A landslide blocked the top of a tributary of Amu-Daria River, forming a natural dam, creating Lake Sarez. The lake is 60 km long, with an average depth of 185 meters, and reaches as deep as 500 meters, the surface of the lake is 80 squ are kilometers. The total volume of the lake is over 16 cubic Kilometers.
The natural dam, named Usoi, forms an impressive shore: it is over 550 meters high and have 15 km long crest. The soil of this dam has become permeable, and the stability of the dam is worsening. In 1994, the lower part of the dam broke off, raising the water level considerably. The dam's stability is only part of the problem. Northern slopes of the lake have very unstable slopes. In the event of an earthquake, it is likely that the cliffs would fall into the lake. It is estimated that a rush of water, equating roughly 1.2 cubic kilometers, would strike the dam with enormous force and cascade over the top. This would weaken the dam, although it may not fully collapse. In this scenari o, there is little doubt that everything would be destroyed in the nearby populous valley. An even more threatening possibility is that earthquake tremors force the entire dam to collapse. If this were to occur, the event could easily become the deadliest n atural disaster in history.
Following are the links to the pdf documents which can be downloaded from this site. The document is a booklet named "Big reservoirs in the seismic dangerous regions in Tajikistan and safety of dams" and is comprised of the following four pdf files.
1- ris1.pdf
2- ris2.pdf
3- ris3.pdf
4- ris4.pdf
Recent international review and inspection undertaken by the World Bank 1999 mission [http://www.worldbank.org/pics/pid/tj65794.txt] provide update on the existing hazards and necessity for the implementation of mitigation procedures.