Geography of Tajikistan - Topography and Drainage

Topography and Drainage

The lower elevations of Tajikistan are divided into northern and southern regions by a complex of three mountain chains that constitute the westernmost extension of the massive Tian Shan system. Running essentially parallel from east to west, the chains are the Turkestan, Zeravshan (Zarafshan), and Hisor (Gissar) mountains. The last of these lies just north of the capital, Dushanbe, which is situated in west-central Tajikistan.

More than half of Tajikistan lies above an elevation of 3,000 metres (9,800 ft). Even the lowlands, which are located in the Fergana Valley in the far north and in Khatlon Province in the southwest, are well above sea level. In the Turkestan range, highest of the western chains, the maximum elevation is 5,510 metres (18,080 ft). The highest elevations of this range are in the east, near the border with Kyrgyzstan. That region is dominated by the peaks of the Pamir-Alay mountain system, including two of the three highest elevations in the former Soviet Union: Mount Lenin — 7,134 metres (23,406 ft) and Mount Communism — 7,495 metres (24,590 ft). Several other peaks in the region also exceed 7,000 metres (23,000 ft). The mountains contain numerous glaciers, the largest of which, Fedchenko Glacier, covers more than 700 square kilometres (270 sq mi) and is the largest glacier in the world outside the polar regions. Because Tajikistan lies in an active seismic belt, severe earthquakes are common.

The Fergana Valley, the most densely populated region in Central Asia irrigated by the Syr Darya in its upper course, spreads across the north-eastern arm of Uzbekistan and Northern Tajikistan. This long valley, which lies between two mountain ranges — the Kuramin Range in the north and the Turkestan Range in the south, reaches its lowest elevation of 320 metres (1,050 ft) at Khujand on the Syr Darya. Rivers bring rich soil deposits into the Fergana Valley from the surrounding mountains, creating a series of fertile oases that have long been prized for agriculture.

In Tajikistan's dense river network, the largest rivers are the Syr Darya and the Amu Darya; the largest tributaries are the Vakhsh and the Kofarnihon, which form valleys from northeast to southwest across western Tajikistan. The Amu Darya carries more water than any other river in Central Asia. The upper course of the Amu Darya, called the Panj River, is 921 kilometres (572 mi) long. The river's name changes at the confluence of the Panj, the Vakhsh, and the Kofarnihon rivers in far southwestern Tajikistan. The Vakhsh, called the Kyzyl-Suu ("red water" in Turkic languages) upstream in Kyrgyzstan and the Surkhob in its middle course in north-central Tajikistan, is the second largest river in southern Tajikistan after the Amu-Panj system. In the Soviet era, the Vakhsh was dammed at several points for irrigation and electric power generation, most notably at Norak (Nurek), east of Dushanbe, where one of the world's highest dams forms the Nurek Reservoir. Numerous factories also were built along the Vakhsh to draw upon its waters and potential for electric power generation.

The two most important rivers in northern Tajikistan are the Syr Darya and the Zeravshan (Zarafshan). The former, the second longest river in Central Asia with a total length of 2,400 kilometres (1,500 mi), stretches 195 kilometres (121 mi) across the Fergana Valley in far-northern Tajikistan. The Zeravshan River, with a total length of 781 kilometres (485 mi), runs for 316 kilometres (196 mi) through the north-center of Tajikistan. Tajikistan's rivers reach high-water levels twice a year: in the spring, fed by the rainy season and melting mountain snow, and in the summer, fed by melting glaciers. The summer freshets are the more useful for irrigation, especially in the Fergana Valley and the valleys of southeastern Tajikistan. Most of Tajikistan's lakes are of glacial origin and are located in the Pamir region in the eastern half of the country. The largest, the Karakul (Qarokul) Lake, is a salt lake devoid of life, lying at an elevation of 4,200 metres (13,800 ft). Tajikistan's second largest water body is the Kayrakum Reservoir, a 44 km (27 mi) long artificial lake in the heart of the Fergana Valley, not far from the city of Khujand in Sughd Province. The lake is fed by the Syr Darya. Another well-known natural lake of glacial origin is Iskanderkul. It is smaller than the Kayrakum Reservoir and lies in the Fann Mountains in western Tajikistan.