Orto-Tokoy (Kasansay) Reservoir — a reservoir in the Ala-Buka District of the Jalal-Abad Region of Kyrgyzstan.
It is located on the Kasansay River, a right tributary of the Syr Darya.Construction of the reservoir began in 1941, but was halted due to the war. After its conclusion, the reservoir was completed — its volume is 165 million cubic meters, the surface area (km²) is 8.0; length (km) is 5.2; width (km) is 3.5; maximum depth is 63 meters.
According to the land allocation case for the Kasansay Reservoir, compiled by the Kyrgyz State Institute of Land Management, "administratively, the Kasansay Reservoir (previously known as Orta-Tokoy until 1958) was part of the Chust District of the Namangan Region of the Uzbek SSR and was subordinate to the Namangan Regional Irrigation Systems Administration." The territory of the reservoir was part of Uzbekistan as an enclave. Accordingly, all expenses for maintaining the water body in a normal state were borne by Uzbekistan.
Periodically, sharp territorial disputes arose between the republics. Only in 2016 did the reservoir fully come under the control of Kyrgyzstan. On October 6, during a state visit by former Kyrgyz President Almazbek Atambayev to Uzbekistan, an agreement was signed between the governments of the two countries on the interstate use of the Orto-Tokoy (Kasansay) Reservoir.
