QUEPUCA-RALCO, Chile -- Lucia Renado Huenchucan lives in the shadow of the Callaquen volcano, a 10,440-foot snow-capped mountain that emits a thin plume of smoke to show it is far from dormant. A member of an isolated Indian tribe, the Pehuenches, she says she has never feared an eruption.
What she does fear is a plan by the government to build as many as six dams along the Bio-Bio, one of Chile's largest rivers, whose crystalline waters run half a mile from here.
Though Mrs. Huenchucan, like most Pehuenches, lives in extreme poverty, she does not welcome the prospect of development, tourism and "outsiders" coming to this place 250 miles south of Santiago, the capital.
"The dams will be the end of Pehuenche life," said Mrs. Huenchucan, who is 43. "We don't trust these people. Yes, we are poor, but we want to live as we have always lived, with the old customs of our ancestors. We want our children to speak our language. The dam will ruin that."
It is not clear that a majority of tribe members share her opinions. The plan to harness the waters of the upper Bio-Bio for electrical power has split this quiet Indian tribe and has also become one of the thorniest ecological debates in Chile.
The question being asked: What cost, in terms of altering the environment and disturbing indigenous cultures, does sorely needed economic development justify? For Chile, where one-third of the people live in poverty, the question is particularly difficult.
"We need to grow to solve our social problems," said Rafael Asenjo, executive secretary of the National Commission for the Environment. "We cannot keep our national patrimony absolutely intact. The environmental groups say: 'Don't touch the forests. Don't touch the river. Stay away from these indigenous people.' That's unrealistic. The urgency of social and economic growth here is too great."
The Bio-Bio's natural beauty is breathtaking, with churning rapids, towering waterfalls and soaring river embankments. Four species of large wildcat hunt the river banks. Andean condors soar overhead, and virgin forest stands untouched, bordering much of the 120 miles of river.
International kayaking and rafting organizations consider the Bio-Bio one of the world's greatest challenges.
"This area is considered one of the least contaminated parts of the planet," wrote Katherine Bragg, an ecologist who has studied the area for almost a decade. "Actually, it's exceptional to find such large areas as this without a significant human presence."
But the project to build the first dam, called Pangue, 20 miles south of here, has weighty economic arguments. Chile's electricity demand is soaring. If generating capacity is limited, industrial development will slow.
The Pangue dam is designed to be one of the most efficient in the world, generating 450 megawatts of power while flooding only 1,250 acres. Brazil had to flood almost 12 times as much land to produce the same amount of power at its huge Itaipu dam. The Pangue project will also require the dislocation of far fewer people.
While the government has approved only Pangue, five other dams on the Bio-Bio have been proposed. In all, the project would flood 52,000 acres along the river and cost more than $3 billion. As with Pangue, where almost $200 million in financing is being sought from foreign investors and the World Bank for a project that is expected to cost $470 million, the entire project is expected to need large amounts of foreign capital.
The company pushing the project through government channels is Chile's recently privatized national electric company, Endesa.
Endesa officials argue that the dam will bring valuable tourism to the lake it creates, and that it will give hundreds of construction jobs to the Pehuenches.
The Pehuenches are one of five major Indian groups in Chile, with a total population of more than 600,000.
Though they were a nomadic people for hundreds of years, the Pehuenches half a century ago were allocated large tracts of land along 80 miles of the Bio-Bio. The rough terrain has so isolated the Pehuenches that until recently they were almost unknown outside the region.
Pehuenche homes are simple structures of rough-cut timbers, dirt floors and open windows. The tribe's members raise vegetables and let their cows, horses, sheep and goats roam the mountains. Winters are harsh.
From interviews along 30 miles of the Bio-Bio, Pehuenches who knew anything about the dam -- and did not oppose the project outright -- said they welcomed the prospect of work and more income, but did not know whether to trust Endesa's promises.
"The main thing we need is work, so how can you oppose this dam?" asked Jose Arsenio Purran, the chief, or lonko, of the Callaqui community of about 460 people 20 miles south of here.
But Leonel Purran Ormenio, 42, said: "We don't know if they will pay for the land they take, and we don't know if they will give us a fair price."
Giving hope to the opposition is the fact that Pangue is having financing problems. The start of construction has been delayed more than a year.
Joining opposition to the project are sporting groups in the United States, who say the river will be lost to rafters and kayakers by the lakes that would be created by the dams.
"If they build Pangue, you've lost half of the good stuff," said Greg Moore, a kayaking guide from Colorado Springs who was interviewed on the river. "And once the second dam goes in, that's all of the good stuff."
The non-Indian opposition to the dam project is considerable and includes most environmental groups, with a small environmentalist organization, Action Group for the Upper Bio-Bio, the focus. Jose Aylwin, a son of Chile's president, is a member of that group. From the government side, the National Commission of Indigenous Groups has opposed the project.