Sarez Lake

Sarez lies in the Pamir Mountains of eastern Tajikistan and is the most dramatic of the country's lakes, both in how it formed and in what it represents. It is among the largest and least disturbed freshwater lakes in the world, and it is reachable only on foot.

How it formed#

On 18 February 1911 an earthquake brought down an enormous landslide into the valley of the Murghab river, burying the village of Usoi and damming the river completely. Water backed up behind the debris and drowned the village of Sarez, which gave the new lake its name. The Usoi dam that holds it is the tallest natural dam in the world at roughly 567 metres.

The lake behind it is around 55 kilometres long and some 500 metres deep at its deepest point, sitting at about 3,250 metres above sea level.

The risk#

The dam has held for over a century, but it is monitored continuously. A failure, whether from seepage or from a further landslide into the lake, would send water down the Bartang, Panj and Amu Darya valleys and threaten communities across Tajikistan, Afghanistan, Uzbekistan and Turkmenistan. Monitoring and early-warning systems have been installed with international support, and the question of how dangerous the dam actually is has been studied for decades without a settled answer.