Kolsai Lakes: Alpine Water, Forests and the Northern Tien Shan

What holds a lake in place halfway up a mountain? At the Kolsai lakes in southeastern Kazakhstan, the answer is the mountain itself: each lake sits behind a barrier of rock and debris that once came down the valley sides and blocked the Kolsai River, so that the water now steps down the gorge in a chain of lakes between dark slopes of spruce. Read with that in mind, the valley becomes a lesson in how elevation, forest and water work together in the northern Tien Shan. On Day 26 of our small group tour through Uzbekistan, Turkmenistan, Kyrgyzstan and Kazakhstan, the group spends a half day walking along part of the lake system.

The Kolsai lakes: a staircase of water in the northern Tien Shan

The lakes lie in the Kolsai gorge on the northern side of the Tien Shan, in the Kungey Alatau, close to the mountain link between that range and the Ile Alatau, the range that rises above Almaty far to the west. A 2022 study by geologists at Satbayev University in Almaty describes three large dammed lakes lying directly in the bed of the Kolsai River. That river is a right-bank tributary of the Shelek, also known as the Chilik, which Kazakhstan’s national tourism agency describes as one of the largest tributaries of the Ili. Water that collects in the gorge therefore joins one of the great river systems of Central Asia on its way down to the plains.

The lakes climb the valley in steps. Our itinerary places the lowest lake at 1,818 metres and about a kilometre long, and the middle lake at 2,252 metres, about five kilometres further up, describing it as the largest of the three. The Satbayev study gives 1,800 and 2,250 metres for the same two lakes. For the highest lake the sources disagree: our itinerary puts it about four kilometres beyond the middle lake and 600 metres higher, while the Satbayev study gives its altitude as 2,660 metres. Either way, the chain spans roughly 850 to 1,050 metres of height from the lowest water to the highest.

For broader orientation to the country, our guide to exploring Kazakhstan and our answers to common questions about travelling in Kazakhstan cover the practicalities. This article stays with the gorge, and with what its water, rock and trees reveal about the mountains.

Lakes held back by fallen mountainsides

The Kolsai lakes are dammed lakes. According to the Satbayev study, all three are held back by dams that rest on a rocky base and are built up of landslide material, with volumes of 300,000 to 500,000 cubic metres at the lower and middle lakes and 150,000 to 200,000 cubic metres at the upper one. The dams are not all alike. The middle lake’s barrier is made of large blocks with little fine material, and the lake has a single outflow; the upper lake’s water drains by filtering through the body of its dam, which is made of finer debris, gravel and earth.

Where the rock came from is a matter of the region’s earthquakes. The same study records that the catastrophic earthquakes of 1887, 1889 and 1911 left huge landslides across the Shelek basin, creating dammed lakes by blocking mountain rivers. Across the wider region, a 2018 study by Medeu, Blagoveshchenskii and Zhdanov counted more than 60 large earthquake-triggered rockfalls and landslides in the Zhetysu, Ile, Kungey and Terskey Alatau, which between them had dammed 26 lakes, and found that earthquakes stronger than magnitude 6 had struck the Ile and Kungey Alatau four times in the previous 130 years.

When the Kolsai lakes themselves formed is less settled than many popular accounts suggest. Those accounts often tie the lakes to the earthquakes of the late nineteenth and early twentieth centuries, yet the Satbayev study describes the cascade on the Kolsai River as more than 1,000 years old. What the sources do agree on is the mechanism: a valley blocked by fallen rock, with the river backing up behind it.

Living with a natural dam

A dam of loose rock is not permanent. The Satbayev study records that before 1984 the lower lake was about 1,520 metres long with a maximum depth of 38.6 metres. On 2 June 1984, higher inflow undermined and collapsed the left part of its dam, and some 509,000 cubic metres of water drained from the lake, lowering the dam by 1.59 metres and sending a mudflow down the gorge. On 2 June 1987 the lake partly emptied again, losing about 217,000 cubic metres and dropping 0.7 metres. The same paper gives the middle lake as 1,150 metres long and up to 57 metres deep, and the upper lake as 580 metres long and up to 23.5 metres deep. These lengths differ from the figures in our itinerary, which gives the lower lake as about a kilometre long and the middle lake as the largest; the sources measure at different times and in different ways.

The water also shapes the gorge. The study describes the lower reaches of the basin, between about 1,600 and 2,800 metres (the study’s zones overlap), as a zone of sharp relief and steep slopes where erosion is active, while the smoother upper basin, between about 2,000 and 3,400 metres, erodes far less. Its authors also point to people: the left shore of the lower lake changes from year to year under what they call a strong anthropogenic load, and they report about 2,000 visitors on a typical weekend.

Kaindy: a drowned forest and a dating puzzle

Within the same national park lies a well-known landslide lake, Kaindy, where the grey trunks of dead spruce stand upright in the water. It shows how science can revise a familiar story. A 2022 tree-ring study by Akkemik, Mazarzhanova and Kopabayeva in the Turkish Journal of Earth Sciences identified the drowned trees as Schrenk’s spruce and dated the lake’s formation to 1911, linking it to the Kemin earthquake. A 2024 study in Natural Hazards by Miramont, Rizza, Guibal and colleagues, comparing tree rings from the submerged trunks with living trees on the slopes, instead placed the drowning shortly after the autumn of 1888 and linked it to the Chilik earthquake of 11 July 1889. The trees are the same in both studies; the date and the earthquake differ.

Does the tour visit Lake Kaindy?

No. Lake Kaindy does not appear on the tour’s itinerary, which spends its time in the region on the Kolsai lakes themselves. Our itinerary describes a half-day walking excursion along part of the Kolsai system on Day 26, followed by free time in the afternoon. Ask a Tour Specialist if you would like to know more about how the free time at Kolsai is usually spent.

Schrenk’s spruce: the tree of the northern slopes

The dark, narrow trees that line the Kolsai gorge are Schrenk’s spruce, Picea schrenkiana, sometimes called Tien Shan spruce. The Gymnosperm Database describes trees up to 60 metres tall with a narrowly pyramidal crown hung with drooping foliage. The species grows in the Tien Shan of Xinjiang, Kazakhstan and Kyrgyzstan, with isolated stands in the northern Pamir and southern Xinjiang, and is named after the German-Russian botanist Alexander Gustav von Schrenk (1816 to 1876), who collected the type specimen in what is now Kazakhstan. These are long-lived trees: tree-ring work has recorded specimens more than 400 years old at several sites, and the oldest known living tree was 502 years old.

Where these forests grow is a matter of water. Britannica notes that forests in the Tien Shan are found principally on the northern slopes, mostly between about 1,500 and 3,000 metres, alternating with steppe and meadow, while southern slopes are usually mountain steppe. The World Wildlife Fund’s description of the Tian Shan montane conifer forests explains why: below about 1,500 metres the land is too dry for coniferous forest, the higher northern slopes receive some 400 to 800 millimetres of precipitation a year, much of it brought by moist air from the northwest, and the thermal tree line lies at about 2,700 metres. In those forests the spruce grows with aspen at lower elevations, Tien Shan rowan higher up, and junipers towards the upper edge of the belt.

Forest and water

The forest also has a part in the water story. Researchers studying spruce stands on the northern slope of Mount Bogda in the Chinese Tien Shan describe these forests as an important part of the mountain ecosystem of an arid region, contributing to carbon storage and water retention, with the tree crown acting as the first interface through which rain passes into the forest, regulating the supply of water to the soil and the plants beneath. The Satbayev study notes that there is no glaciation in the Kolsai basin, so the lakes are not fed by glaciers; the middle lake, it records, has three inflowing tributaries and a single outflow. The study describes the climate of the wider Shelek basin as sharply continental, with large daily and annual swings in temperature.

A national park and a biosphere reserve

The gorge is protected. Kolsai Koldery State National Nature Park was established by Resolution No. 88 of the Government of Kazakhstan on 7 February 2007, covering 161,045 hectares, of which 64,715 hectares were forest land transferred from the Kegen state forest enterprise. Kazakhstan’s Ministry of Ecology describes the park as spanning 1,800 to 3,500 metres, with five altitudinal belts of vegetation between 1,400 and 4,265 metres, more than 1,000 plant species, 19 of them in the Red Book of Kazakhstan, and 51 mammal and 160 bird species. Among the mammals listed in the Red Book are the Tien Shan brown bear, the Turkestan lynx, the snow leopard, the Tien Shan argali and the Pallas’s cat, or manul. On 15 September 2021, at the 33rd session of the International Coordinating Council of its Man and the Biosphere Programme, UNESCO added the park to its World Network of Biosphere Reserves.

How much walking is there at the Kolsai lakes?

A half-day walking excursion along part of the lake system on Day 26, with free time in the afternoon. Our itinerary notes that the highest lake, four kilometres beyond the middle lake and 600 metres higher, is not accessible on our tour. The tour as a whole is rated Level 3, Moderate to Challenging: participants must be in excellent health, extremely mobile and live an active lifestyle, and activities may include up to six hours a day of continuous strenuous, moderate to fast-paced activity over varied terrain. Ask a Tour Specialist how the Kolsai walk is paced, and raise any health questions, including about altitude, with your doctor before you travel.

Where does the group stay at the Kolsai lakes?

At a local guesthouse for two nights. Our itinerary names Seisek’s Guesthouse or similar for the nights of Days 25 and 26, with breakfast, lunch and dinner included on both days and dinner on Day 26 eaten together at the guesthouse.

How do the Kolsai lakes fit into the tour’s days in Kazakhstan?

They come at the end of three days east of Almaty. On Day 24 the group explores Altyn-Emel National Park and its petroglyphs on the Ili. On Day 25 it visits Aulie-Agash, a 700-year-old tree in the settlement of Kieli-Agash, and Charyn Canyon, then drives about 150 kilometres to the Kolsai lakes for dinner. After the walk on Day 26, Day 27 brings some free time before the transfer back to Almaty, and the tour ends after breakfast on Day 28.

Reading the gorge

The Kolsai lakes reward the traveller who asks how they came to be. Earthquakes brought rock down across the river; the river backed up behind it; spruce colonised the shaded northern slopes where enough moisture falls; and the forest helps regulate how that water reaches the soil. It is the same mountain system, further south in Kyrgyzstan, that our article on Son-Kul and the high pastures of Kyrgyzstan explores at 3,000 metres, and our four-country journey through Central Asia sets both within the whole route.

Travelling in a small group with an Odyssey Program Leader, you reach the Kolsai lakes at the close of a long journey from the oasis cities of Uzbekistan. If you would like to end that journey among mountain water and spruce forest, our 28-day Stans tour gives the lakes two nights and a morning on foot.