CHONG KHNEAS, Cambodia -- A decade ago, Chan Kimoeun could pilot his skiff across the turbid water of the Tonle Sap, stay out for two days and bring home as much as 400 pounds of fish. On this day, he returned from five nights of floating torpor with a mere 50 pounds -- hardly enough to cover the costs of fuel or the rice he cooked during the trip.
"All that time for nothing," said Chan, whose four children depend on his catch to pay for school and any prospect of escaping this floating town on the trash-strewn shores of Cambodia's largest lake. "There are fewer and fewer fish."
Throughout Southeast Asia, farmers and fishermen complain that China's thirst for hydroelectric power is choking the Mekong River, which sustains some 70 million people.
(Peter S. Goodman -- The Washington Post)
While Chan futilely drifted, construction crews 650 miles to the north in the Chinese province of Yunnan labored to secure energy for China's breakneck industrialization. Dumping truckloads of boulders and concrete, they fashioned a 300-foot-high hydroelectric dam on the Mekong River.
China's rapid development is changing the global economy as the country absorbs vast quantities of energy and raw materials and presses wages and manufacturing costs lower. But the changes along the Mekong highlight another aspect of China's ascendance: Its threat to the environment.
Japan blames China's smokestacks for increased volumes of acid rain. Chinese timber companies have pressed into neighboring Burma to harvest hardwoods. And throughout Southeast Asia, farmers and fishermen complain that China's thirst for hydroelectric power is choking the Mekong, a waterway that sustains some 70 million people.
Known to Americans largely for the struggle over its fertile southern delta during the Vietnam War, the Mekong winds 3,000 miles from the highlands of Tibet to the South China Sea, irrigating crops, nurturing fish and supporting shipping across a vast area.
China already has completed two dams across the river, with two more under construction and four others planned. Despite the geographic distance, scientists are beginning to document links with growing environmental troubles downstream. A team of researchers last year at the Finnish Environment Institute concluded that China's Manwan Dam cut by one-half the amount of sediment in the water at Chiang Saen, Thailand. The researchers also concluded that China's network of dams would likely lead to lower water levels in the river, less flooding of the Tonle Sap, less transfer of nutrient-rich sediment -- and a degraded fishery.
The stakes are considerable. The Mekong is a crucial artery of nutrients for the Tonle Sap, for example, whose fish provide most of the protein in the Cambodian diet. The fish catch following the end of the wet season in 2003 declined by roughly half compared with the previous year, according to a report by Milton Osborne, an Australian researcher. While overfishing and habitat destruction are also factors, researchers place some of the blame on China's dams.
"China, they will work for their own country," said Khy Tanglim, a Cambodian cabinet minister who heads a team devoted to Mekong policy. "We are downstream, so we suffer all the negative consequences. If there is no more water for us, no more fish, no more vegetation, this is a big disaster."
The catch in northern Thai waters declined by half from 2000 to 2004, according to the Southeast Asia Rivers Network, an environmental group. Concern is also mounting about Vietnam's Mekong River Delta, whose soils produce roughly half of the country's agricultural output. Less fresh water coming down river could allow more saltwater to spill in from the South China Sea, ruining farmland. More than 40 percent of the Mekong passes through Chinese territory, and about 16 percent of the runoff that feeds it originates in China -- a figure that jumps to perhaps 40 percent in the dry season, Osborne said.