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(in the USSR, Tedzhen), a river in Afghanistan, Iran, and the USSR. The Harirud is 1,150 km long and drains an area of 70,600 sq km. It originates in Afghanistan at an elevation of about 3,000 m. Until the Herat Oasis in Afghanistan it is a mountain stream, flowing in a narrow valley. In the oasis it flows in a broad valley, where its waters are used for irrigation; below the city of Herat the bed is sometimes dry. Upon leaving the oasis, the Harirud again acquires the characteristics of a mountain stream and in this area serves as the boundary between Iran and Afghanistan. Further downstream the valley broadens once again, and the river serves as the boundary between the USSR and Iran. In the Turkmen SSR the river flows in a broad valley, breaking up into several channels. Here, all of the river’s water is used for irrigation of the Tedzhen Oasis.
The Harirud is fed mainly by snow. High water occurs between March and May. The mean flow rate near Polekhatum, 325 km from the river’s end, is about 30 cu m per sec; the maximum is 990 cu m per sec. From August to November the river is usually dry. Turbidity is high—about 100,000 g per cu m. The Harirud does not freeze.
On the Soviet portion of the Harirud there are reservoirs for seasonal regulation of flow: the Tedzhen Reservoir (useful capacity 142 million cu m) and the Second Tedzhen Reservoir (180 mil lion cu m). There is also a small inlet reservoir. The lower course of the river is also fed by the Karakum Canal. The city of Tedzhen is located on the Harirud.