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Amudarya River Basin

Reservoirs and flow regulation

More than 35 reservoirs were constructed in the Amudarya basin with a capacity of over 10 million m3 each. The aggregate capacity of these water reservoirs exceeds 29.8 km3. The Amudarya cascade of reservoirs operates according to specific scheme, allowing regulation by two main river channel reservoirs (Nurek and Tuyamuyun) and several on-system reservoirs on the Karakum, Karshi and Amu-Bukhara canals and small rivers. Total capacity of reservoirs on the main river is about 17 km3. The principle scheme of flow regulation regime along the Amudarya is as following. The Nurek water reservoir provides multi-year water storage for area up to Kerki gauging station. Water releases depend on run-off variations of the Pyandj, Kafirnigan, Surkhandarya and Kunduz rivers, and water demands of downstream area from Kerki. Tuyamuyun reservoir is operating with a seasonal regime. It catches over released water from the Nurek reservoir and some additional flow of the Amudarya. Releases from it start usually in February-March.

Nurek reservoir and HPS

Tuyamuyun hydroscheme

As level regime in the river is very important issue for providing of the required withdrawal to the main canals, their intakes schedule should be agreed with releases from the Nurek reservoir. Intake to the Karakum canal executes during low flow, and vs, to the Karshi and Amu-Bukhara during high flow along the river. BWO is responsible for monitoring these processes in linkage with water storage in the Nurek and Tuyamuyun reservoirs.

On-system reservoirs are playing role of seasonal water storage (unconsumed autumn-winter flow). Some of them were constructed within the cascades of pumping stations: Talimardjan reservoir on the Karshi canal with a capacity of 1.5 km3, Tudakul and Kuyumazar reservoirs on the Amu-Bukhara canal. The same and also as sediment regulator Hauskhan reservoir on the Karakum canal with capacity of 0.9 km3. A few water reservoirs were constructed on the small rivers. These are South Surkhan reservoir on the Surkhandarya river with total capacity of 800 million m3, reservoirs on the Tedjen and the Murgab rivers, and 14 small reservoirs in the Kashkadarya river basin with total capacity about 1.5 km3.

If constructed, the Rogun reservoir on the Vakhsh river can increase the degree of multi-year regulation of the Amudarya up to 0.86. Today it is about 0.76. At existing reservoir capacities, the guaranteed yield of water in low water years (90 percent probability) may reach up to 62 km3. However, in the past seven years, the irrigation-and-hydropower mode of operation for which the reservoirs were designed has sharply changed in favor of hydropower. In spite of the Nurek reservoir is currently operating in the hydropower mode the capacity of the Tuyamuyum reservoir is enough for compensation those changes in flow regime.