Defusing Africa's Killer Lakes

In a remote region of Cameroon, an international team of scientists takes extraordinary steps to prevent the recurrence of a deadly natural disaster

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By January 2001, the researchers had assembled rafts and piping at the site. Attached to a raft in the middle of the lake, a 5.7-inch-diameter pipe reached 666 feet to the deepest water layer. The Cameroon military provided emergency oxygen tanks for all workers in case of a rogue carbon dioxide release. After everyone retreated to distant high ground, Halbwachs pushed a remote-control button to activate a pump that primed the pipe. Within seconds a 148-foot spray shot into the sunlight at 100 miles per hour, and the small crowd let out a cheer. The degassing of LakeNyos had begun.

But with 5,500 tons of carbon dioxide still pouring into the lake annually, one pipe barely keeps up; Kling and Evans estimate it may take more than 30 years before enough dissolved carbon dioxide can be vented to make the lake safe. Five pipes, the researchers say, might do the job within five or six years—but so far funding has not materialized. The venting of the lake cannot happen too quickly, as far as locals are concerned. Families have begun drifting back into nearby hills, siting their compounds in high passes but venturing down to the forbidden zone by day. "You can't keep people out forever," says Greg Tanyileke of Cameroon's Institute for Geological and Mining Research. "We need to go faster."

lakemonoun sits in steamy low country, surrounded by dozens of miniature, dormant volcanic cones. The area was not evacuated after the disaster in 1984; the nearby village of Njindoun alone has 3,000 residents. Yet, as at Nyos, carbon dioxide levels have been building up for years. The U.S. OFDA and the French government have pledged money to vent the lake, and preparations for installing the first pipe were begun earlier this year, as I looked on this January.

Plans call for the installation of three pipes in Monoun, which could render the lake safe in only three years. The lake is smaller and shallower than Nyos, but continuing buildup had made Monoun more volatile. Some 210 feet down, carbon dioxide had reached 97 percent saturation. At that depth, says Kusakabe, if the layer were stirred up by only three feet, the water could start bubbling and trigger an explosion. His colleague, Bill Evans, advised caution: "Let's not go splashing around too much out there," he tells me.

Sections of pipe and other components were stacked by the lake and under military guard when photographer Louise Gubb and I arrived. Ateam headed by Kusakabe was eager to start, but locals made it clear that first it was necessary to contact the lake spirits. "Man can build machines, but machines can betray man," said Njindoun elder Mamar Ngouhou. "We must move slowly."

The next morning, a crowd assembled at the shore. Under a tree, several shamans stirred a blackish green paste in a ceremonial bowl and then, carrying cornstalks and an ancient wooden gong, led a solemn procession to the water. The head priest, Amadou Fakueoh Kouobouom, beat the gong while crying out to ancestors. On the lake, men in fishing canoes tossed offerings of fruit, salt and palm oil into the water. Kouobouom dipped his forefingers into the paste, and people lined up to lick it off. (The foreigners balked until a young man whispered, "This will prevent harm from coming to you on the lake.") Then came Muslim prayers; most villagers are also followers of Islam. A feast of rice and smoked fish ensued. Finally, a live ram was carried to the water; an Imam cut its throat and held the knife in the slit until the blood stopped flowing. Only after this four-hour ceremony was it time to proceed.

The Japanese technicians leaped up, wrenches and screwdrivers at the ready, and began fastening together two small rafts to support monitors and a vent pipe. A 15-man team wrestled the rafts into the water. Kling and Evans motored out in a dinghy and gingerly suspended instruments for measuring carbon dioxide and temperature. Later that day, the two American scientists drove to the spot where the first victims of the Monoun explosion had fallen. The team had installed a solar-powered carbon dioxide detector, equipped with a loud siren and marked with a hand-painted skull and crossbones sign and instructions to flee if the alarm sounded. They were pleased that it was still working. Three weeks later, engineers headed by Halbwachs finished installing the first pipe for Monoun. It has worked well so far.

the countryside around LakeNyos was beautiful but eerie. At a nearby spring, one of several fed by deep lake waters, carbon dioxide bubbled up. A dead hawk lay in a mud puddle next to a dead mouse, both apparently asphyxiated. Out in the woods, white cattle appeared suddenly like ghosts, then melted into the bush silently, their owners nowhere to be seen. We slept on a lakeside promontory, millions of stars overhead, amid cricket songs and the barks of baboons. It was the dry season; farmers on the heights were torching the bush to prepare for planting. At night great rings of land-clearing fires burned above the lake.

One morning we visited what was left of Lower Nyos, now mostly impenetrable brush. Along the dirt road, the foundations of a few mud-brick houses were still visible. Lines of trees marked the edges of what had once been yards. In the center of the former marketplace lay a large pile of rotting shoes. After the disaster, soldiers had buried the bodies in mass graves, whose locations were quickly lost in the rapidly revegetated bush country. That was a nearly unbearable loss: here, people routinely bury family members in the front yard so they can serve them meals, ask their advice and take comfort from their presence.

Survivors have overcome great challenges. On the day of the Nyos disaster, Mercy Bih was on her way to Wum, carrying about $100—a considerable sum in Cameroon—to buy supplies for her 26-member extended family. All her relatives were killed. She was 12. She returned the groceries and was reimbursed the $100, which she saved. Now 29 and the mother of two, she's the proprietor of the Lake Nyos Survival Good Faith Club, a four-table restaurant in Wum serving cold beer and the best grilled mackerel for miles. "I was lucky," she says. "Some people got left with nothing."


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