Chatyr-Köl ( ; ), also Chatyr-Kul (), is an endorheic alpine lake in the Tian Shan mountains in At-Bashy District of Naryn Province, Kyrgyzstan; it lies in the lower part of Chatyr-Köl Depression near the Torugart Pass border crossing into China.
The mean annual temperature in the lake basin is , with mean temperature of in January, and in July. The maximum temperature in summer is , and the minimum one in winter is . Some 88-90% of the lake basin's 208âÂÂ269 mm of annual precipitation falls in summer. From October to end of April the lake surface freezes, the ice becoming as much as 0.25-1.5 m thick.
The water of Chatyr Kul Lake is yellowish-green with water transparency of up to . The mineralization of the lake ranges from 0.5 to 1.0 milligrams per liter (chloride, hydrocarbonate, sodium and magnesium type of mineralization). The salinity of the lake is 2 ppt. Mineral sources in the south part of the lake have mineralization of from per liter and pH = 5,8-6,0. Flow rate is in winter and during summer. 41 small streams debouches into the lake, of those 21 originate in Torugart Range and 20 - in Atbashy Range.
Negative water balance of the lake over the last decades causes the decline in the lake level. The mineral water from the sources is cold and has a strong mineral taste and flow first into the small Chatyr Kul lake that is about 1,5 meters higher than the actual Chatyr Kul.
Since 1998, a section of the lake and its shore (3,200 ha land, 3,954 ha water) is protected as part of the Karatal-Japyryk Nature Reserve. The whole lake has been a game reserve (IUCN category IV) since 1972. The game reserve was established to protect water fowl, including the bar-headed goose. The lake is a Ramsar site of globally significant biodiversity (Ramsar Site RDB Code 2KG002).