In the hinterland of Borneo an old lady is perched on a couch improvising into a microphone. A chorus of about 50 people, cross-legged on the floor around a small amplifier, chimes in at the end of each line with a harmonic drone.

“God made this land for us to enjoy,” the old woman sings. “But the devil, through Taib Mahmud, has taken it away.” The group erupts into laughter at the characterisation of Sarawak’s Chief Minister as the agent of the Devil and the skilful rhyming it has been phrased with.

But the singer’s intricate melody is a melancholy one, and the words, sung in Kayan — one of over 30 indigenous languages in the Malaysian state — are a lament for the loss of the life she once had. Fifteen years ago, 10,000 people were moved from their land along the valley of Sarawak’s biggest river to make way for the Bakun dam — a hydroelectric project with a reservoir the size of Singapore, which was labelled a “monument to corruption” by Transparency International.

The communities had been promised opportunity and development in their new homes but instead found themselves surrounded by oil palm plantations, with allocations of land for farming too small to support them and no access to the forests and rivers they relied on. There is a school and a clinic, electricity and running water at the resettlement area of Asap, but there is also poverty, purposelessness and dysfunction, and many people have left to find low-paid jobs in the towns.

It’s a story that looks set to play out in other parts of Sarawak, as it is in countries across south-east Asia, particularly the Mekong region, where a hydroelectric dam-building boom is taking place that NGOs say will jeopardise the livelihood of millions of people who rely on fish and forest products from the Mekong River basin.

Critics of big dams like the organisation International Rivers argue that large, centralised power projects are no solution for rural communities in developing countries. In addition to the huge social costs, they say, industrial-scale dams significantly impact on biodiversity, crop production, water quality and fish populations, and their reservoirs can produce as much greenhouse gas as coal-fired power plants.

In Sarawak, where decades of logging have stripped the big timber from the forests and left the state’s primary industry in decline, the government is pushing ahead with plans for a massive transformation of the economy based on big dams. By offering cheap hydropower and generous tax breaks, opening up over half the state’s land area to industry and agribusiness and building transport infrastructure and industrial centres, the government aspires to increase GDP fivefold, quadruple per capita income and create 1.6 million jobs by 2030.

One new large-scale dam has just been completed in Sarawak and nine more are on the drawing board. As Crikey reported last month, Australian companies with links to government are among foreign businesses providing expertise to help build them.

Ten days ago, as water rose on a 245-square-kilometre area that will become the reservoir of the new Murum dam, a group of indigenous protesters who’d been manning a sticks-and-tarpaulin blockade for nearly three months finally dismantled the barricade and agreed to leave their river valley homes.

Most of the 1500 people displaced by the dam are Penan, a traditionally nomadic people who up to a generation ago lived from hunting and gathering in Sarawak’s forested interior. From the 1980s many Penan communities fought fiercely with petitions and blockades against the logging that threatened their survival. In 1990 a Penan delegation led by Swiss adventurer and environmentalist Bruno Manser visited Australia as part of a world tour aimed at publicising the plight of the forest people. But it was a fight they ultimately lost, and the Penan are now among Sarawak’s poorest and most dispossessed peoples.

State electricity company Sarawak Energy says it has spared no expense building facilities and setting up programs for the people displaced by the new dam. But while the company’s resettlement plan describes the groups as in transition to a “cash-based way of life” that could take a generation it envisages their economic self-sufficiency through cash cropping, which they have no experience in, within six years, after which support will cease. The groups will be “allowed to access” forest areas to collect food and jungle products for their own consumption but will not own these, will not be close enough to the areas for easy access, and are likely to have this right later revoked.

For indigenous rights groups in Sarawak the dams are just the latest chapter in a long story of dispossession. The difference, though, they say, is that the effects are irreversible. “Once the dam is built basically your land is gone,” said Mark Bujang, the head of Sarawak NGO Borneo Resources Institute. “At least with logging or oil palm, the land is still there.”

Meanwhile, a large group of people whose villages are threatened by the proposed 1200-megawatt Baram project are maintaining a blockade of the site they set up in October. As Crikey has reported, the Baram dam would flood the traditional lands of an estimated 20,000 Kayan, Kenyah and Penan people.

The blockades in Sarawak highlight a slow dismantling of cultures that is taking place as a land known for its jungle and tribal peoples is deliberately opened up to industry and commercial agriculture by a government accused of systematic self-enrichment.

“What the government is doing when they’re flooding all these areas is actually killing off the culture, the traditions of the community,” Bujang said. “It’s basically ethnocide.”

The small crowd in the longhouse clap and cheer as the old lady ends her song, and everyone helps themselves to traditional dishes and sits down to eat. But after the meal the group breaks up. It is Sunday, and the visitors have to head back to town. The hosts switch on a karaoke machine to entertain the kids.