The Central Asian republics are currently operating the water resource system of the Syr Darya basin under allocation schemes developed prior to the collapse of the Soviet Union. The allocations were designed under the assumptions that: (1) the region was a part of one country; (2) the region's hydro-technical facilities were developed to serve agricultural irrigation; (3) water deficits could be alleviated by an inter-basin transfer from Siberian rivers; (4) upstream countries would be provided with needed wintertime heating fuels; and (5) upstream hydropower developments could be facilitated through the development of the Kambarata dams.

Construction of Toktogul Dam and Reservoir was completed in 1975. Storage and hydropower capacity is listed in Table 1. Four other constant volume hydropower facilities, along with Toktogul, compose the Naryn-Syr Darya Cascade. The other dams were constructed between 1962 (Uch-Kurgan) and mid 1980’s (Kurpsai, Tashkumyr, and Shamaldysai).

After the collapse of the Soviet Union, the five republics agreed to continue the water allocations adopted in 1982. However, the primary storage reservoir (Toktogul) is located in, and owned by, the upstream country of the Kyrgyz Republic, and the bulk of the agricultural production is located in the downstream countries of Uzbekistan and Kazakhstan. The Toktogul Reservoir operating regime was modified in 1991 to provide for wintertime power production to replace suspended fuel deliveries. In an attempt to secure an appropriate release regime to satisfy the downstream irrigation needs, agreements have been reached in the past three years to provide for the exchange of wintertime fuel supplies for summertime irrigation releases from Toktogul Reservoir. This report detals the use of an optimization model to help analyze the operations of Toktogul reservoir and the Syr Darya system.

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