The stations will employ the world's tallest concrete dam - 305 metres - on completion in 2014, to generate a combined capacity of 8,400 megawatts. They are located on the border between Mianning, Muli and Yanyuan counties in the ethnically diverse area of Liangshan .

The concrete arch dam at Jinping No1 station will generate electricity and store energy before directing the flow through four 16.7km diversion tunnels inside the mountain to the Jinping No2, which will be the largest power plant on the river, with a capacity of 4,800MW.

The unique geographic position at the Yalong River bend, a sparsely populated area, has seen the 55 billion yuan project touted as a gift from heaven by hydraulic engineers.

But people living close to the river bend have less to thank the gods for. Nearly 8,000 have been forced from their homes for the Jinping plants. One of the displaced, Mianning villager Xu Weisheng , 42, has been lucky enough to find a job as a truck driver at the dam site, which is usually off-limits to locals.

He said his family was one of 13 households evicted from the mountainside village of Zhuangzi in Lianhe township four years ago to make room for the dam workers.

'I know I am extremely lucky to work here, which brings me 3,000 to 4,000 yuan a month. Locals are generally not allowed to enter the dam site without permission, let alone get a job,' he said.

Most hydropower developments across the country discourage the employment of local people.

Mr Xu feared that if his identity as a local resident were unveiled he would be kicked off the construction site.

Apart from his job, his family and his elderly parents depend on a one mu (666 square metre) rice paddy and the annual government subsidy of 600 yuan per person.

'Few people want to come here because we don't have enough land like before, when we could raise pigs and chickens on the mountains. And the compensation we have got is far from enough to cover the cost of building our new homes,' he said.

His fellow mountain dwellers, numbering in the hundreds, have been hit hard by the construction of the twin power stations.

'The diversion dam project, while far from completion, has already taken away almost all fresh water on the mountain, leaving people there high and dry,' he said.

Mr Xu said people converted their dry land into paddy fields two decades ago when he was a village head after the Mofanggou power plant was built in the early 1970s. Mofanggou was the first hydropower project on the Yalong.

'Now that water has gone, those who still live on the mountains have to return to the old days when we lived on dry land,' he said with a sigh.

But their grievances have not been heard by local authorities or the main developer of the plants, Ertan Hydropower Development.

Dozens of disgruntled villagers tried to block the only road leading to the dam site last summer. But their protests were soon put down by armed soldiers, with several villagers detained for allegedly leading the demonstrations.

While many people in Lianhe township doubt pledges by the authorities that the development will improve their lives, villager Yu Xinzhi, 69, said she wanted to be relocated for safety reasons.

Her home, two brick houses on a hill overlooking Moufanggou village, has been surrounded by high-tension cable towers for electricity transmission for two years.

One of the towers stands by the wall of her bedroom.

'It must be bad for our health to live under the high-voltage cables,' she said. 'No one has ever asked our opinions on them and no one has bothered to tell us if they are indeed bad for our health. We don't know what exactly the impact it will have on us and we just have to live in the shadow of fear.'

Her son, Zhang Jiufu , 37, said 12 villagers living on the hill had been demanding the right to move.

'But officials told us we fell short of the relocation standards and rejected our application for resettlement,' he said.

Villagers cannot afford to move themselves. 'Even if we could, where shall we go?' Mr Zhang asked.

They have not received any compensation for the health risks posed by the high-voltage cables, with the only restitution they have received being 10,000 yuan for the use of their farmland to build the towers.

Mr Zhang said he was particularly worried about the impact on his two children, one in primary school and the other in high school.

Their fears are well founded, according to a British study, which concluded in 2005 that children living within 200 metres of high-voltage power lines have a 70 per cent greater chance of developing leukaemia.

Their grievances, and those from Zhuangzi villagers, have been muzzled by the authorities, who often brush off the downside of hydropower development in the name of poverty alleviation.

'It is true that we local people are not happy with the project, but we won't cause big troubles for authorities. Why can't we be hired just like those workers from other places? We are poor and want to get some benefits from the project built at our doorsteps. Is there anything wrong with that?' he asked. Who cares about us?'