About 25 years ago, the building of another dam more than 200 miles east of here flooded her property, driving a plague of poisonous snakes, insects and jaguars onto her land, she said, before submerging it completely.
Now, after starting a new life in Altamira, the government is telling her she needs to leave again, this time to make way for the Belo Monte dam, which will flood a large swath of this city, displacing thousands of people.
“This dam is a threat to me because I no longer have the energy I once did,” said Mrs. da Silva, 53, whose family of 11 shares a three-bedroom home with banana trees in the back. “We can no longer invest and build another house like this one. For me, this is like throwing away a lot of hope.”
But she will have little choice. Initial construction on the Belo Monte dam, which will be the third largest in the world, is slated to begin by next year.
Persistent opposition by environmental and indigenous groups, even with help from high-profile figures like the Canadian-American movie director James Cameron, failed to stop the $11 billion project, which will produce electricity for big cities like São Paulo while flooding about 200 square miles of the Xingu River basin.
Indigenous communities say the dam will devastate their lands and force about 12,000 from their homes. They say it will reduce the river level, destroying their traditional fishing industry.
The city of Altamira, above the dam, faces the opposite problem, with about a third of it to end up under water. Thousands of residents will be relocated.

The Invasão dos Padres neighborhood in the Brazilian city of Altamira, in the Amazon, will be under water after the construction of a massive dam. Foto: André Vieira


Last week, regional indigenous leaders met here to plan a dramatic occupation of the dam’s construction site, but after four days of discussion failed to produce a consensus, the protest was called off. Members of nongovernmental groups trying to stop the dam are starting to sound resigned.
“The groups are still divided,” said Christian Poirier, the Brazil campaign leader for Amazon Watch, who attended the meeting. “There are a lot of political considerations right now for the indigenous leaders. Some have been neutralized by handouts or threats.”
The government has pushed hard to ensure that construction on the dam, decades in the planning, would begin before President Luiz Inácio Lula da Silva leaves office at the end of this year. When some of Brazil’s most important private construction and civil engineering companies grew jittery about the financial risks earlier this year, the government raised its investment stake and is now financing more than three quarters of the project.
Valter Cardeal, director of engineering for Eletrobrás, Brazil’s state electricity company, said the project would have no negative economic impact on any indigenous community. He acknowledged that there would be reduced water flow downstream, but not enough, he said, to affect fishing.
He said Belo Monte would bring “improvements and advances” to indigenous people, including sanitation, better health and education services, and “territorial security” for their lands.
As to Altamira, he said people forced to relocate would be compensated and most would benefit.
In the low-lying neighborhood of about 700 homes where Mrs. da Silva lives, for instance, some homes are built on stilts to avoid seasonal flooding.
Mr. Cardeal said the relocation would lift those residents out of such “precarious, subhuman conditions.”
He said that the government would provide assistance to small farmers and that the construction companies had agreed to put $280 million in a sustainable development plan for the region.
Such assurances are disputed by dam opponents and many residents.
At a meeting in March, indigenous leaders waved bows and arrows, and threatened to go to war to stop the construction. But two tribes, the Xikrin-Kayapó and the Parakanã, have since dropped their opposition, citing concerns about losing government handouts, Mr. Poirier said.
He and others involved in the discussions accuse the government utility Eletronorte of trying to divide the indigenous groups by buying off leaders with gifts or threatening to deny their communities health or other services.
Mr. Cardeal and a spokesman for Electronorte denied those accusations.
Altamira residents are divided. Some are hopeful that the dam will bring jobs and money to this lightly populated municipality, Brazil’s largest.
During construction, the dam is expected to provide an estimated 20,000 jobs, although initially, at least, many of the workers will have to come from elsewhere, said Elcirene de Souza, the head of the Altamira federal employment office. She said 90 percent of the work force in Altamira was not qualified for the skilled jobs the project needs.
She said she was concerned that the influx of workers would usher in gangs, drugs and crime, as has happened in the building of other dams. Government officials, though, have told residents that they hope to avoid such problems by not creating a separate village for workers, as they have in the past, but incorporating the workers into the city.
Already résumés from applicants are flooding in, about 8,200 in the first four months of the year, from at least five Brazilian states, Ms. de Souza said.
Residents like Mrs. da Silva, skeptical of government promises of subsidies and relocation packages, are mainly concerned about where they will live. She said the government badly underpaid her for her last house, paying only the cost of construction materials, not the market price. She fears the same will happen again.
“When they arrive, they come with a price table showing what they will offer for our house, and we either accept that price or they won’t offer anything else,” she said. “They will tell me how much my house is worth and will not relocate me anywhere else.”
She fears for her husband, a fisherman. “He only has two more years left to get his retirement plan, but we aren’t sure if he will be able to fish for another two years,” she said. “Do you think the fish will hang around here? The fish know where to escape to, but us, we need to go where they throw us.”