BANGKOK (AlertNet) - A planned hydropower dam in northeast Cambodia could displace around 5,000 people, create health problems from poor water quality and sharply reduce fish stocks which would lead to a rise in poverty and hunger for tens of thousands of villagers, campaigners and academics said.

Vietnam has said it will invest $600 million to build two hydropower plants on the lower Sesan river in neighbouring Cambodia, which are expected to produce over 500 MW of electricity.

The Cambodian government, which sees hydropower development as a top priority, is currently studying feasibility plans for the dams. Once completed, the Lower Sesan 1 and 2 plants will feed several areas in Cambodia and Vietnam, one of the region's most fastest-growing economies.

The NGO Forum on Cambodia (NGOF) says the 75-m Lower Sesan 2 plant may have a negative effect on fisheries as far downstream as the Mekong Delta in Vietnam -- the rice bowl of the country -- and as far upstream as Laos and Thailand in a report it launched on Wednesday.

A Vietnamese-commissioned assessment of the environmental impact of the dam noted it would "very likely" stop fish migration, affecting the diets and livelihoods of some 30,000 people upstream most of whom get 95 percent of their daily protein intake from fish. NGOF puts the number at 78,000.

Construction of the dam which is expected to take four years will inundate almost 25 percent of the surrounding agricultural land, while damaging the quality of the water which in itself could create health problems, Chhith Sam Ath, NGOF's executive director, told AlertNet.

Other campaigners are worried that the dam will have a negative impact on biodiversity and ethnic minorities' culture and land rights.

OPPOSITION

Many villagers living along the Sesan and Srepok rivers are worried that dam means losing their land, crops and livelihood and being forcibly resettled on to less fertile land.

In a three-part community video, which was posted on YouTube and produced with help from NGOF, a villager appeals to the government not to go ahead. "We are simple people that depend on the river for everything," he says.

An elderly woman says she is worried the new dam will cause homes to be flooded and property to be lost. "I'm old now, so it will be impossible for me to plough new fields and start a new farm," she said.

Locals are also unhappy about compensation plans.

NGOF said people upstream were offered money to compensate for one year's worth of fish loss, when the loss would be felt for generations. However, it said no compensation was proposed for downstream villagers, who are expected to suffer from poor water quality and a reduced quantity of water.

Cambodia is not alone in focusing on hydropower. Vietnam, Thailand and Laos as well as China are all in the race to build dams on the Mekong. The river supports one of the world's most diverse fisheries, rivalled only by the Amazon, with an estimated commercial value of around $2 billion.

Countries in the lower Basin are heavily dependent on the freshwater from the Mekong -- meaning the 'mother of all rivers' in Lao -- and its tributaries and its unique cycle of flood and drought for crop cultivation and fishery.

A recent United Nations report warned that China's construction of mega dams such as the recently completed Xiaowan, which at 292 m is the world's tallest, is a great threat to the river. Already, Vietnam's Mekong Delta is facing a reduction in ground water due to over-pumping.

The dams are likely make the situation worse "by lowering dry season flows and increasing saline intrusion; by stopping fish from entering Ton Le Sap lake which is a breeding ground; and by cutting back on spring floods which wash and enrich the soil," Professor David Dapice, an economist at the John F. Kennedy School of Government at Harvard University, told AlertNet.

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