BY TYLER BRIDGES
McClatchy News Service

The Xingu River, the largest tributary of the Amazon, runs wide and swift this time of year. Its turquoise waters are home to about 600 species of fish, including several not found anywhere else on the planet. A thick emerald canopy of trees hugs its banks, except in places where man has carved out pastures for cattle.

Now, the Brazilian state power company wants to harness a section of the Xingu by building the world's third-biggest dam. The Belo Monte dam would drown 200 square miles of tropical rainforest -- an area equivalent to the sprawling city of Tucson, Ariz. -- and flood the homes of 19,000 people. It would be one of more than a dozen dams the government is planning to construct on tributaries of the Amazon.

Belo Monte would be only the latest assault on the Amazon tropical rainforest, home to one in 10 of the world's known species.

Stephan Schwartzman, director of tropical forest policy at the Environmental Defense Fund, said 18 percent of the Amazon, an area nearly two times the size of California, had been cleared since the mid-1960s.

What happens to the Amazon rainforest has huge consequences, because a shrinking rainforest hampers the planet's ability to rid the atmosphere of carbon dioxide. Brazilian officials say Belo Monte and the other dams are necessary to switch on more living room lights, power expanding companies in the world's ninth-largest economy and create jobs as the nation begins to slide into recession.

ORGANIZING NATIVES

The effect of Belo Monte on the Indians it would displace is central to the dam's opposition. Under Brazil's Constitution, Indians must ''be heard'' when dams would affect their land, which potentially gives them veto power over new dams.

Environmentalists are organizing riverside dwellers to speak up against Belo Monte by describing how it would submerge their homes and land. They organized a meeting last month in the community that locals call Volta Grande, which in Portuguese refers to a curve in the Xingu known as the Big Bend.

Euclides De Oliveira, a wiry 32-year-old fisherman with a dark mustache, listened quietly as activists described an unhappy future.

''What you say makes me afraid,'' de Oliveira said when he finally spoke up. ``It will end our way of life.''

Environmentalists emphasize that Belo Monte would increase global greenhouse gases by devastating the rainforest and by releasing the methane gas stored in river vegetation. They add that the Xingu's low level during the dry season would force the government to build five more dams to regulate the water flow.

Some critics even say that dams such as Belo Monte could become white elephants if global warming dries up parts of the Amazon, as some computer models suggest.

Instead of building dams, a World Wildlife Fund-Brazil analysis found, the government could meet the country's energy needs by upgrading existing energy systems and pushing for the rapid development of wind, solar and biomass. In one example, the study reported that Brazil loses 16 percent of the power it generates through an old and faulty distribution system, compared with an international rate of about 6 percent.

Brazilian President Luiz Inácio Lula da Silva has won plaudits worldwide for his role in pushing for Brazilian cars to switch from gasoline to cleaner ethanol produced from sugarcane.

Lula has continued to champion big energy projects that create jobs, devastate the rainforest and produce campaign contributions to his Workers Party from big construction companies.

He also has said pointedly: ``The Amazon belongs to Brazilians.''

Lula provided crucial support for two controversial dams under construction on the Madeira River, in the western Amazon.

Belo Monte would be built in the heart of Pará, a state that's home to an explosive mix of poor settlers, cattle ranchers, loggers and scammers who fake land titles.

In 2005, an assassin in Pará hired by a wealthy rancher shot and killed Dorothy Stang, an American nun who had fought the powerful on behalf of the landless.

A sign of the tension over Belo Monte came at a public meeting in Altamira last May. There, Indians clubbed and slashed an electric company executive.

''It was a shocking and regrettable act,'' said Glenn Switkes, the Brazil-based representative of International Rivers, a California-based nonprofit group. ``But it defines what's at stake and shows that the determination and resistance by indigenous people is likely to be strong.''

Bishop Erwin Kraulter has 24-hour police protection because of death threats for opposing the dam and butting heads with the powerful ranchers association.

''The dam will have an irreversible impact,'' Kraulter said in his residence in Altamira.

He has some hope that the government won't advance the dam after he met with Lula on March 19 and got the president to agree to meet with opponents in late April.

BUSINESS INTERESTS

Business and political leaders in Altamira support Belo Monte because of the development it will bring.

''With the dam, we'd have more income to improve infrastructure,'' said Altamira's mayor, Odileida Sampaio. She hopes that the dam will produce money to pave 600 miles of the Transamazon highway and connect Altamira to the city of Maraba to the east.

Sampaio said the company that wins the project to build the dam must pay for new roads, schools, health clinics and houses.

The debate over whether to build dams in the Amazon isn't new. Opponents stopped one massive dam planned for the Amazon in 1989.

It was an earlier version of Belo Monte. A coalition of U.S.-based environmentalists, Brazil's Kayapo Indians and the star wattage of Sting, who shone an international spotlight, prompted the World Bank to withdraw needed loans.

Belo Monte now is a kinder and gentler dam, said Jose Muniz, president of Eletrobras, the giant state power company.

''It's the best site in the world for a dam,'' he said.

Muniz said he expected to win approval to solicit construction bids in October and begin work on Belo Monte next year. The dam would cost $10 billion and wouldn't open until 2014 at the earliest.

Muniz said the government had learned from its mistakes and was taking many steps to protect the environment and minimize its effect on indigenous peoples.

''Brazil needs dams if it wants to become a developed country,'' Muniz said. ``It is a clean form of energy.''

Opponents hope that the courts will reject it because of the damage it will do to indigenous people and the rainforest.

At the meeting March 21, about 70 people gathered at one of the riverside dwellings in Volta Grande. It was the home of Fernando Florencio de Sousa, who grows cacao, coffee, rice, corn and yucca on 600 acres that abut the Xingu River.

Officials from the electric company have visited the area four or five times.

''They promise us that we'll have a much better life,'' de Sousa said, "that we'll have electricity, running water and live in a nice house. I don't believe it.''