Issyk (river)

The Issyk River is a river in Kazakhstan that crosses the Issyk Lake (not to be confused with the much greater Issyk Kul Lake in Kyrgyzstan) and the town of Esik.

One of the largest rivers on the northern slope of the Trans-Ili Alatau, its headwaters come from 32 active glaciers that cover an area of 43 km². The largest glaciers are the Zharsai (its exposed length is 3.8 km and area 6.37 km²), the Grigoriev (3.6 km long, area 5.86 km²), and the Pal'gov (3.8 km long, 6.95 km²}, come down from the crest of the main divide whose average absolute height is over 4,000 m. Within the mountains the river is 22 km long, the gradient at its longitudinal profile is 102 m in 1 km, and the basin area is 210 km².

In its upper reaches the river flows down a very steep slope (10-15°) over the deposits of a moraine overgrown with some vegetation and forms a deep (as much as 70 m) canyon; then, in front of the terminal vegetation-free moraine of the Pal'gov glacier, its longitudinal profile flattens out abruptly_ Here the river forms numerous branches over an outwash plain. Below Lake Akkul' (its absolute elevation is 3,140 m), the longitudinal profile undergoes another sharp drop because a large mountainous obstruction damming the lake and, perhaps, because of moraines buried under the obstruction.

In 1963, the overspill of Issyk Lake caused a large flood.