As work begins on Cambodia’s biggest dam, those advocating against its construction have warned that the region’s rush for hydropower will have a disastrous effect on millions of people who rely on the Mekong River to survive.
Last month, workers began preparing an area in northeastern Cambodia for a huge hydropower project, the 400-megawatt Lower Se San 2 Dam.
The $800 million dam on the Se San River, a major tributary of the Mekong, will take the Cambodian, Chinese and Vietnamese companies behind it five years to build.
Opponents say the dam’s real cost will be paid by the millions of people who rely on fish for the bulk of their protein intake.
Cambodians eat more freshwater fish than any other nationality, says Eric Baran, the senior research scientist with WorldFish, an independent group that studies food security. “So people have become very reliant on this source of animal protein," he explained. "And, fish is also by far the first source of animal protein.”
Thailand and Vietnam have a flourishing livestock sector - with advanced production of chickens and pigs. But, in Cambodia, fish accounts for 80 percent of the population’s animal protein intake.
Scientists estimated the Lower Se San 2 Dam could reduce the total fish yield of the Mekong Basin by 9.3 percent.
“So it’s 9.3 percent of 2.1 million tons - which is a gigantic amount," said Baran. "In other words, this expected loss represents around 200,000 tons per year, which is much more than the whole marine sector of Australia. And, nine times more than the annual inland fish catch in Germany or the U.S.”
That estimated drop is presented in a study that Baran co-authored, published last year in The Proceedings of the National Academy of Sciences
Researchers found that of the dozens of tributary dams planned for Laos, Vietnam and Cambodia, the Lower Se San 2 Dam was by far the most destructive for fisheries.
That is because the Se San River is one-third of a network of rivers in northeastern Cambodia that constitute three out of four so-called “highways” that migratory fish use to access their breeding sites.
The Lower Se San 2 Dam will be built a few miles downstream of the confluence of two of those three rivers: the Se San River and the Sre Pok River. Scientists said the dam’s eight-kilometer wall will block migratory fish - which make up 40 percent of all fish in the system - from accessing their breeding grounds.
The study also found that the Lower Se San 2 Dam would reduce by six to eight percent the flow of nutrient-rich sediment, which is vital to fertilizing the small rice fields of hundreds of thousands of subsistence-level people.
And, it warns that a series of mainstream dams planned for Laos and Cambodia would have even worse effects.
“If the 11 mainstream dams are built, it’s expected that up to 75 percent of the sediments will be blocked by dams,” Baran said.
Countries that build dams on the mainstream of the Mekong River must first carry out detailed impact studies to measure how they could affect their neighbors.
But dams built on tributaries - such as the Lower Se San 2 Dam - require no such study.
Ame Trandem is the Southeast Asia Program Director for International Rivers
, an independent environmental group. She said the environmental impact assessment for the Lower Se San 2 Dam is “wholly inadequate.”
“Because it’s a tributary project it has never undergone that same level of consultation. And, so the information that’s been produced by experts hasn’t reached the government in the same kind of channels. I do think, if more information was reaching the government, it would reconsider,” Trandem stated.
VOA tried to speak with Cambodian authorities about the dam’s impact, but was told that the man responsible for hydropower dams - the Minister of Industry, Mines & Energy Suy Sem - was too busy to schedule an interview until after Cambodia’s general election in July. Other ministry staff would not speak and a list of questions sent to the minister was not answered.
Meanwhile, work on the Lower Se San 2 Dam has started and thousands of people who live in the areas that will be submerged by the dam’s vast 300-square-kilometer reservoir have been told they will have to move.
One of them is 37-year-old Pa Tou. He said none of the 400 ethnic minority families in Srekor village on the banks of the Se San River wants to leave.
Pa Tou said the dam will deprive them of everything - their rice fields, orchards and homes. Currently, they can grow enough rice in a year to feed themselves for the following year and they are able to raise some livestock for food and some for sale.
Pa Tou, who has three daughters, said that will not be possible at the relocation site, which is miles from the river. He said the land there is poor for farming - most of it is rocky or covered with trees - and there are no health clinics and no schools. He fears they will all be left much worse off.