Martin Litton, a bold whitewater navigator and even bolder advocate for preserving the wildlands of the American West, has died at age 97.

Litton had been in hospice care and died at his home in Portola Valley on Sunday, said Alison Sheehey, programs director at Sequoia ForestKeeper, where Litton was president.

Litton was "active in protecting the environment until just a few days ago," Sheehey said in an email to The Associated Press.

Litton fought his way to the center of some of the biggest environmental battles of the last century, fiercely opposing the damming of the Colorado River in the Grand Canyon — a fight he would win — and the building of the Diablo Canyon nuclear plant on the California coast — a fight his side would bitterly lose.

He was an unapologetic extremist for environmental causes, saying in one 2012 interview that if he could issue royal decrees he'd take down the Golden Gate Bridge.

"I never felt it did any good to be reasonable about anything in conservation," he was quoted as saying in a statement on his death from Sequoia ForestKeeper, "because what you give away will never come back — ever."

He also opposed the building of a ski resort in Mineral King Valley in California's Sierra Nevada and spearheaded the creation of Redwood National Park.

A California native who spent childhood summers camping in Yosemite National Park, Litton made his name and his legend as a guide on the Colorado River, pioneering and popularizing oar-powered recreation through the Grand Canyon and eventually earning a spot in the International Whitewater Hall of Fame.

He first made the trip down the river in 1955, always preferring wooden boats to inflatable rafts, and kept making it into his 90s.

He would go on to found several environmental organizations but also served on the board of the more mainstream Sierra Club from 1964 to 1972, when he was a loud voice for taking hard stances, making sure the club didn't acquiesce to a pair of federal proposals to erect dams in the Grand Canyon.

"If I hadn't done what I did, I think it's very likely at least one of those dams would have been put in the canyon," Litton said in a 2011 interview with the Los Angeles Times, which first reported his death Monday. "I was the only one screaming about them."