By Jana Donovan

For The Post

They wade through freezing water. They carry heavy loads on their backs at altitudes where horses are unable to walk. They risk their lives traversing the steep slopes of one of the world's highest mountain ranges.

Not quite supermen, the group of Czech scientists working in Tian Shan, Kyrgyzstan, are nonetheless on a very important mission: to prevent an ecological disaster that could kill hundreds of people, displace thousands more and contaminate a key water source of neighboring Uzbekistan, a country of 23 million people.

"It would be a world-class catastrophe," says Bohumír Janský, a Charles University geologist who is on the team of experts monitoring the lakes and land around the Tian Shan Mountains.

Global warming is melting glaciers at the top of these mountains at an alarmingly fast rate. Runoff is pooling at high altitudes, creating an increasing number of mountain lakes. Although majestically pristine, those lakes are virtual time bombs.

Sooner or later, they could burst and run over the stone-and-ice dikes that have naturally formed around them. The result? Catastrophic avalanches hitting towns and villages in the valley below.

"Hundreds of people would die, and hundreds of thousands would suffer," Janský says.

The most vulnerable area is Petrova Lake, near the Kumtor gold mine, a major source of income for Kyrgyzstan.

Recently, the team discovered that the lake is 70 meters (230 feet) deep, 50 meters deeper than previously thought. The amount of water in the lake has greatly increased during the past decade, raising the risk that it will eventually breach its banks, which could send a 20-meter-high wave into the sedimentory basin of the nearby mine.

The water would then mix with the toxic cyanide that is used in processing golden ore from the mountains. The runoff would spill into the Naryn River, which flows into the Syr Darya River, which in turn is one of the main water sources for Uzbekistan (it irrigates the Ferghana Valley, the country's breadbasket).

With the goal of preventing just such a catastrophe, the Czech Environment Ministry appointed the team of experts in 2004 to monitor the lakes. The project was chosen in order to fulfill a European Union obligation for each member state to make efforts to assist third-world countries. The Finance Ministry is paying for the research, which so far has cost about 9 million Kč ($409,463).

Risky work

"Working at an altitude of 4,000 meters above sea level is risky," says Michal Černý, a geologist with the Jihlava-based firm Geomin, which is spearheading the project. Černý recently returned from his latest stint in Tian Shan, where he and colleagues have spent the past three summers.

"We balance ourselves on free-standing boulders, walk on very steep slopes on the lake shores and sail on inflatable boats on ice-cold water," he says.

Cars can only be driven to the lower part of the valley. Horses are then used to carry material and equipment. "The last part of the road is not even accessible for horses, so we have to carry everything on our backs — tents, rubber dinghies, food," Černý says. "All told, the load weighs hundreds of kilograms."

For now, the six-man team has focused on geographic and hydrological surveys of the lakes. And they have presented their main recommendations — such as which lakes to dredge and where additional barriers are needed — to the Kyrgyz government and the Kumtor Gold Company, which runs the nearby mine as part of a joint venture with a Canadian firm.

Černý says the World Bank, after reviewing the Czech findings, offered to finance key work at Petrova Lake, such as dredging and barrier installation.

Those would be key steps toward preventing a disaster. But there are about 200 other such lakes in Kyrgyzstan, 60 of which are considered to be in an extremely dangerous state.

As Černý darkly notes, "It's impossible for us to do detailed research on all of them and prevent all catastrophes."

In 1998, a truck carrying cyanide to the gold mine overturned and the toxin contaminated the Barskoon River. Twenty people died, thousands fell ill, and farmers went broke, as nobody wanted to buy their poisoned apples.

That same year, Shakhimardan River burst its banks. Hundreds were killed in the resulting tide of water, stones and earth.

"Its water volume was only 40,000 cubic meters [1.4 million cubic feet]," Černý says. "The volume of Lake Petrova, in contrast, is a thousand times more."