MCDONELL: The Three Gorges Dam is the biggest in the world. It’s also the largest hydroelectric project ever built. As well as generating massive amounts of electricity, it symbolises China’s growing power as a country that can tame the elements like no other.

It’s changed forever the Yangtze River, which divides China’s north from its south. A river, that at its most spectacular, cuts through three gorges in a row. Four hundred million people live in the Yangtze basin, a third of China’s population and as the dam nears completion, there’s growing unease.

DAI QING: The Three Gorges Project may destroy the Yangtze River. It is human activities which have turned the best gift from God and the smartest natural arrangement into a disastrous river.

MCDONELL: Chongqing is the largest city in Western China. It’s seen as the great hope for opening the country’s vast inland to economic development. Thirty million people live in the greater city area, many moved here after their villages were flooded as part of the Three Gorges development.

We’ve come to Chongqing to start our journey to the three gorges. Even here, over six hundred kilometres away, its impact is felt in so many ways so we’re hoping as we travel down the Yangtze to see first hand what effects the dam has been having recently.

First we go to see Professor Lei Hengshun. He was a member of China’s normally compliant parliament when sixteen years ago, a quarter of its delegates abstained or voted against the new dam.

PROFESSOR LEI HENGSHUN: In the 1992 People’s Congress, when discussing this issue I didn’t vote for it. I didn’t agree with constructing the Three Gorges Project at the time.

MCDONELL: The eighty-two year old geologist from Chongqing University has made the dam his life’s work.

PROFESSOR LEI HENGSHUN: I worried about two things. One was how to properly resettle the one million people. That was a big issue. The other worry was the environment. We worried most about water quality.

MCDONELL: Those who live and work on the river know about its health first hand.

LIU GUJUN: After the Three Gorges Dam was built the rubbish began to float on the river. Therefore, the Three Gorges Project actually created a new job – river garbage relief.

MCDONELL: Liu Gujun says his team is determined to ensure that there’s now less and less rubbish in the river.

Is the Yangtze River very important to your life and culture?

LIU GUJUN: It is very important.

MCDONELL: Why?

LIU GUJUN: Because we’ve lived by the Yangtze River since our childhood. We love the Yangtze.

MCDONELL: Where is the house you used to live in?

LIU GUJUN: It is already under the water.

MCDONELL: Really?

LIU GUJUN: Yes. My house… it used to be over there under the red boat.

MCDONELL: Over there?

LIU GUJUN: Yes… yes… yes.

MCDONELL: Liu Gujun’s house is under this floating restaurant, yet he says his real home is the Yangtze, which is why he’s doing this job to clean it up.

DAI QING: The speed of the running water has slowed down, so it doesn’t carry the garbage away. I believe the water quality has become worse.

MCDONELL: Writer and agitator Dai Qing has been the most vocal critic of the Three Gorges Project. Her family history has given her a degree of protection to speak out. In the 1950s, her father-in-law built an important dam outside Beijing. Former Chinese leader Mao Zedong even came to visit.

Five decades later, she says the environmental destruction caused by the greatest dam of them all is hardly mentioned.

DAI QING: I think Chinese people have very limited resources to learn about the Three Gorges Project. No Chinese media organisations are allowed to discuss its problems – especially TV, radio and newspapers.

MCDONELL: For hundreds of years the river has been used to carry cargo from the inland to the port of Shanghai and back. Also for moving a great many people. The local porters are renowned for their ability to carry huge amounts of luggage up and down these steep hills. They take on a TV crew’s gear without even blinking.

The Three Gorges is an iconic place for Chinese people. You only have to go as far as the 10 yuan note to see that. On the one side we’ve got Chairman Mao the former leader of the country and on the other, the Three Gorges and here we are.

The beauty of the Three Gorges comes from the dramatic size of their cliffs. As the water’s gone up, they’re not as striking as they were and the river still has ten metres to rise. Some say this is a small price to pay for a dam, which can control disastrous flooding and could soon power one third of the households in China. For Chinese scientists, this is a genuine dilemma.

PROFESSOR LEI HENGSHUN: China has such a large population and demand for energy. Government officials, scientists and other people all know that the Yangtze River, stretching over several thousand kilometres, is a living river. If you cut it… it’s just like a human being – you damage the body… you can’t do this. From head to foot, it’s all connected. But China has no choice.

MCDONELL: As we move through the gorges, the ruins of what were once vibrant communities are dotted along the steep riverbanks, yet for those who remain here on higher ground, this is not just a question of lost beauty.

DAI QING: The biggest problem the Three Gorges Project may face in the future is geological disasters. The water level rose from 135 metres to 156 metres, and will rise to 175 metres, saturating both banks. This will make the disasters more severe and more frequent.

MCDONELL: When you travel on the Yangtze, you can’t miss the landslides which have collapsed into the river and the huge walls being built to try to contain them. While the water level is slowly rising, it’s also fluctuating as the water is released and then held back down river to control seasonal flooding.

PROFESSOR LEI HENGSHUN: In the future there will for sure be geological disasters of a type we’ve never seen. Why? Because we’ve never made the water level go up by 30 metres, and then go down by 30 metres. Going up… going down… going up… going down. I’ll explain it simply. If we hold an iron wire, and bend it, it is very hard. But if we bend it back and forth and do this repeatedly, the iron wire will break.

MCDONELL: This is an area already prone to geological instability but the villagers we met said the rising river level has increased the number and ferocity of landslides.

SU SHIYU: Ever since the water level went up the houses in this area have all been affected. Cracks began to appear in the walls. Sometimes we can hear the land making big explosive noises like firecrackers.

MCDONELL: Su Shiyu showed us the major structural damage done to his house.

Ah, so this is it? When did it happen?

SU SHIYU: In May last year.

MCDONELL: He’s adamant that these cracks were caused by the rising waters of the Three Gorges Dam. In this unusually cold winter, the holes in the wall make it very hard to keep warm but they believe there could be worse to come.

SONG WENZHEN: What am I afraid of? I’m afraid that the house will collapse.

SU SHIYU: How afraid?

SONG WENZHEN: Very much afraid.

SU SHIYU: If the house collapses at night when we’re asleep there’s nothing we can do about it.

MCDONELL: Su took us to see his mother’s house to show us that theirs is not an isolated example.

[Looking at crack in wall of house] That is it, right?

SU SHIYU: Yes, right here. It’s pretty serious. Since the water storage last year the bricks have been falling down. When the land quakes, the bricks fall off.

MCDONELL: Is your mother worried?

SU SHIYU: Of course my mum’s worried! She’s an old woman! What if the house collapses while she’s asleep? We wouldn’t find her. She’s worried.

MCDONELL: These villagers say they can’t afford to fix their houses. They want the government to either pay for their repair work or move them. They’ll have to join the waiting list though because others are more desperate with their houses sliding down the hill and we came across some pretty stark evidence that the situation is indeed becoming serious.

These enormous pylons were sunk into the ground to try and stop landslides. As you can see, they haven’t worked as the water level has come up, the land around here has become increasingly unstable and now they look like they’re about to fall over themselves.

We’re almost at the Three Gorges Dam and the snow is getting heavier. We get a glimpse of our destination off in the distance. As the winter night draws in, on the hills around the dam, you can see what this project is all about – electricity going out in all directions and lots of it.

CAO GUANGJING: The electricity generated by the Three Gorges Project is equivalent to the power generated by 50 million tonnes of raw coal. So the project can avoid the emission of about 100 million tonnes of carbon dioxide.

MCDONELL: Before we’re allowed anywhere near the dam, we meet Project Vice President Cao Guangjing. He refuses to answer any questions on its direct environmental impact. He says he’s just an engineer.

CAO GUANGJING: That Chinese people have built such a project proves that the country’s technology management and state power has reached a significant level.

MCDONELL: When we finally arrive there, the dam is a sight to behold. Inside this concrete monolith, there are dozens of turbines capturing the power of the Yangtze and turning it into electricity. The cargo ship locks are already working. If you spend a little time watching them open and close, you can see how busy the shipping traffic has become. One of the reasons for the dam was to create a deeper river to carry larger ships. The finished structure will also have an enormous passenger ship elevator, big enough to lift whole vessels up the wall of the dam and after seventeen years, it’s finally nearly completed.

Well this is it, the mighty Three Gorges Dam! It’s either an enormous mistake or an engineering marvel that will power China into the 21st century. It’s definitely big and produces a lot of electricity but the question for China is, was building the dam really worthwhile?

When we’re invited inside the dam to speak to shift engineer Li Tianzhi, he certainly thinks so. He couldn’t believe his luck when he got a job here.

LI TIANZHI: It’s a very important project to the Chinese people. As a university graduate in this new era, I feel very proud to work here.

MCDONELL: Li told us that the power generated by these turbines actually fluctuates quite a bit according to the seasons. In the winter, less electricity is produced but with the summer rains and the flooding river, comes an electricity bonanza. This electricity comes without the pollution of coal-fired power. Even one of the dam’s staunchest critics has become something of a convert.

Do you think hydropower is a good choice for mankind?

PROFESSOR LEI HENGSHUN: We should look at this question in this way… China used to rely mainly on coal. Sulphur dioxide and carbon dioxide are the main cause of global warming. I think at present, it’s fair to say that the positive aspects have outweighed the negative aspects. However, in the future we should pay close attention to the many problems and keep doing our research to solve them.

MCDONELL: But for others, the problem runs deeper because in China the financial benefits of mega engineering projects still outweigh environmental and social concerns every time.

DAI QING: China has a saying now – “silver bridge, golden highway and diamond dam”. If you get a contract to build a bridge it means you have silver. If you get a contract to build a highway it means you have gold. If you get a contract to build a dam, you have diamonds – the temptation is just too big.

MCDONELL: China plans to dam many more of its rivers. It’s also building dams overseas for developing countries envious of China’s startling economic growth. But the Three Gorges Project has shown that if you want the benefits of hydropower, you’d better prepare for the costs.