Monsoon rains have always shaped life in this remote corner of Laos, where villagers traditionally work rice paddies and find food in mist-shrouded mountain jungles.
But this wet season, the tropical downpours herald radical change for the people living in this part of one of Asia's poorest countries -- the massive run-off will soon be harnessed to fill the country's largest dam.
The Nam Theun 2, a World Bank-backed, 1.45-billion-dollar hydropower project on the drawing board for more than a decade, has long been dogged by controversy over its impact on local residents and the environment.
For more than two years now bulldozers and trucks have criss-crossed the plateau near the Vietnamese border, and 8,000 workers have cleared forests, moved earth and blasted rock to build the country's largest infrastructure project.
Now the "NT2" is taking shape, and by late next year, engineers say, its reservoir will have flooded 450 square kilometres (175 square miles) of land that has been home to 6,200 people living in 17 villages.
To its proponents, the 1,075-megawatt dam will kickstart badly needed economic development in the landlocked Southeast Asian country of six million people, most of whom are farmers living on less than two dollars a day.
When it starts operating in December 2009, some 95 percent of the power will be sold to Thailand, earning Laos revenues estimated at almost two billion dollars over 25 years, which the communist country has pledged to spend on poverty reduction.
After that, the dam, a project co-managed by Electricite de France and several Thai companies, will be handed to Laos and will keep generating electricity.
To its critics, NT2 threatens to become yet another dam disaster, destroying forests and agricultural lands and affecting two tributaries of the Mekong along with the lives of tens of thousands of people who live in their catchment areas.
A panel of experts warned in February that, while construction was on schedule, the resettlement, agricultural and compensation programmes had fallen behind, with only one dry season left before the dam area is to be flooded.
"The main current constraint is the delayed ability of the intended livelihood system to provide sufficient food and income prior to 2009 and possibly beyond that date," they said.
The Nam Theun 2 Power Company (NTPC) is building larger houses, schools and clinics for displaced villagers, but it concedes that hundreds of families still lack new homes in the current rainy season, blaming timber shortages.
Its CEO Bernard Tribollet said a project of this scale was bound to result in some problems. "Yes, on the social side, we are facing difficulties," he said, "and when we face difficulties, we correct the difficulties."
NTPC stressed that it has created jobs, built and upgraded 140 kilometres (87 miles) of roads, cleared unexploded ordinance left from the Vietnam War, and is helping protect 4,000 square kilometres of watershed rain forest.
The critics, led by the California-based International Rivers Network (IRN), have warned that the resettled communities, set amid poorer soils with far less grazing land, will not be able to sustainably produce enough food.
When AFP visited the plateau last week at NTPC's invitation, several resettled villagers said handouts of meat and fish, meant to ensure sufficient protein intake until they again become self-sufficient, had stopped months ago.
In the new village of Sop On, one 36-year-old man said he was hoping for a better future promised by the project but was still waiting for his new house and recently had to sell his last buffalo to buy rice.
A company official, when asked about the claims, said district authorities had decided to end meat and fish handouts to families after nine months to avoid a cycle of dependency, but that rice was still being given.
Opponents of the dam also point to looming problems downstream.
NT2 will block the Nam Theun and divert its water through a vertical shaft to drive turbines before releasing it into another river, the Xe Bang Fai.
This will double the river's flow, increase erosion and impact water quality because of increased sediments. The IRN also says that, if vegetation is not cleared from the reservoir, water will be polluted by decomposing biomass.
Under the project developers' own worst-case scenario, the Xe Bang Fai will see a fish-kill of up to 85 percent.
The NTPC has pledged to compensate 70,000 people downstream for this impact and for land lost to construction with 16 million dollars-worth of cash and programmes such as fish ponds, forestry, weaving, pig raising and mushroom farms.
The developers have admitted that it will take years for these measures to become widely sustainable.
World Bank country manager Patchamuthu Illangovan conceded that "the social programmes, especially resettlement, got off to a slow beginning while construction picked up pace."
But he said concerns were being addressed and highlighted the economic contribution of the first dam project the bank has backed since the mid-1990s.
"If Nam Theun 2 is done well, it provides a model for how Laos can do responsible hydropower development and be a vibrant provider to the region as a whole," he said.
Six large dam projects now operate in Laos, most feeding power to energy-hungry Thailand. Four more are being built, and dozens are being considered, including several dams on the Mekong mainstream.
Environmentalists warn of the impact on fragile eco-systems and fisheries, the main source of protein for millions living along the Mekong.
But to developers here, dams are becoming more attractive as the cost of fossil fuels rise -- and cash-strapped Laos leaves little doubt about its enthusiasm for becoming the region's hydro-powerhouse.
"The Lao government has the ambition of transforming Laos into the battery of the region," said government spokesman Yong Chanthalangsy. "Nam Theun 2 is one of the tools for the government to achieve this goal."
