Vakhsh
The Vakhsh River, also known as the Surkhob (in north-central Tajikistan) and the Kyzyl-Suu (in Kyrgyzstan) is a Central Asian river, and one of the main rivers of the nation of Tajikistan. It is a tributary to the Amu Darya river. The river's source lies in Kyrgyzstan; it then flows through Tajikistan for a length of 524 kilometers before joining the Panj river to form the Amu Darya at the border of Tajikistan and Afghanistan. The average annual discharge of the Vakhsh is 19.6 cubic kilometers. The river, which is fed mostly by melting glaciers, achieves maximum flow during the summer months of July and August. The river flows through very mountainous territory, which frequently restricts the river's flow to narrow channels within deep gorges. Within Tajikistan, the river's catchment area is 31,200 square kilometers. The largest tributaries of the Vakhsh are the Muksu and the Obihingou.
The hydroelectric power potential Vakhsh River has been thoroughly exploited by the Soviet Union and its successor Tajikistan. There are currently five completed hydroelectric dams along the Vakhsh within Tajikistan, including the world's tallest completed dam, the Nurek. The five dams supply 90% of the country's electric power generation capacity. In addition, another four dams are planned or under construction, including the Rogun Dam, which will supersede the Nurek as tallest in the world once it is completed. The existing dams along the Vakhsh make Tajikistan the highest hydroelectric power producer per capita in the world.
The Vakhsh is subject to blockage by landslides caused by earthquakes in the seismically active region. Such landslides pose a significant threat to the river's dams and hydroelectric power generation. In response to an earthquake-caused landslide in 2002, Tajikistan was granted a low-interest loan from the Asian Development Bank to mitigate the potential impact of the landslide.