The National Park Service is backing the plan, which would transfer 785 acres of land in Olympic National Park – including 222 acres of officially designated wilderness – to the Quileute Tribe.

The transfer would require a reversal by Congress, which declared 95 percent of the park a wilderness area in 1988.

The plan is unusual because the closest thing to an ironclad promise on Capitol Hill is a wilderness designation, at least in theory.

But supporters of the plan say there are extraordinary issues at play, the most important of which is the tribe’s safety.

After a killer tsunami hit Japan last month, members of the Quileute Tribe worried anew that their tiny 1.5-square-mile reservation in La Push, along the Pacific coast of the Olympic Peninsula, could go next.

“Our people live in danger daily knowing that we could be hit by a tsunami,” said Bonita Cleveland, the tribe’s chairwoman. “It could be wiped out in a heartbeat. It’s important to move our people to higher ground for the protection and safety of our people.”

The Quileute are proposing to use part of the land to relocate homes, a school and several other reservation facilities. The tribe has an enrolled membership of more than 1,000, with roughly 400 of them living at the site.

“We’d eventually like to move everyone to higher ground,” Cleveland said. “We’re at sea level.”

Olympic is the largest national park in Washington state, with nearly 1 million acres. It includes forest land, beaches and coastline, temperate rain forests, glacier-covered mountains and unique ecosystems.

The deal comes after many years of negotiation between the tribe and the Park Service.

Dave Reynolds, a spokesman for Olympic National Park, said the Park Service “is supportive of the need for the land transfer.” He could not provide an estimate of the value of the property.

Cleveland said the value would be impossible to quantify.

“To native people, I don’t know how you put a cost on land,” she said. “When once we were able to move and roam all over, up and down the coast, and now we’re restricted to one square mile. So yes, we can’t put a value on the land. Long ago, we would move freely. Today, we can’t move freely. Now our lives are in danger.”

Since passing the Wilderness Act in 1964, Congress has changed the borders of wilderness areas at least 19 times. Eight of the changes involved 67 acres or less, according to the Congressional Research Service.

At least 10 of the deletions involved parcels larger than 300 acres, including one in Washington state that allowed expansion of an existing ski area onto a parcel of land that had been designated as wilderness.

In another case, in Vermont in the mid-1970s, a 2,725-acre parcel was redesignated after a private farm was erroneously included in a wilderness area.

It’s far more common for Congress to create new wilderness areas. From 1968 through 2010, Congress passed 117 laws designating additional wilderness.

“Congress giveth, and Congress can taketh away,” said Bill Arthur, deputy national field director with the Sierra Club. Changes to wilderness tracts have been “quite infrequent and very modest in scale,” he said.

The Sierra Club is backing the proposed transfer, he said.

“The Quileutes are in an untenable position, and it needs to be fixed. … Nobody wants to see them limited into an area that makes them highly at risk for a tsunami,” Arthur said. “I think it’s real.”

Doug Scott, policy director for the Campaign for America’s Wilderness, said the threat of a tsunami was never taken into account when the wilderness boundaries for Olympic National Park were first drawn. And with the Quileutes facing “a real risky situation,” he said, it’s appropriate to reconsider the lines.

“No one I know in the wilderness movement thinks that it’s a one-way street and that questions can never be raised,” Scott said. “I think it’s the sign of a stronger and more mature wilderness movement. … It will take an act of Congress to adjust the boundaries.”

After making a lobbying trip to Washington, D.C., tribal leaders won the backing of Rep. Norm Dicks and Sen. Maria Cantwell, both Washington Democrats, who have introduced bills that would transfer the property to the Quileute Tribe.

“This is something we should do to protect the tribe and the children,” said Dicks, the top-ranked Democrat on the House Appropriations Committee. “You’ve got to do it. I mean, this is very legitimate, I think.”

Dicks said the tribe is living “right on the ocean” and needs to move.

The tragedy in Japan “is a reminder of the importance of preparing coastal communities for future tsunamis,” Cantwell said. She called the legislation a “sensible plan to increase economic opportunity and safeguard Quileute families and their property from devastating floods and tsunamis.”

Cantwell said the legislation also would settle a longstanding dispute over the reservation’s northern boundary and guarantee public access to beaches. In addition, she said, it would designate as wilderness more than 4,000 acres of land that’s currently within the park’s boundaries.

While the tribe is using the most recent tsunami as a way to try to sell the plan, Cleveland said that negotiations on a deal have actually been in the works for nearly three decades. She said she’s optimistic that Congress will approve the plan.

“You have to be optimistic,” she said. “It’s for the protection of our people’s lives. If we were hit by a tsunami, there could be no La Push. There could be no more Quileute people. I would hope that would be a priority in somebody’s mind. We need to live just as well as anybody else.”

Under the agreement, the National Park Service would transfer the property to the Bureau of Indian Affairs, which would hold the land in trust for the tribe, according to Donald Laverdure, principal deputy assistant secretary for Indian affairs with the U.S. Department of Interior. He told the Senate Indian Affairs Committee on Thursday that the department is backing the plan and that “all of the concerns have been met.”

The tribe is perhaps most well-known for its role in Stephenie Meyer’s “Twilight” novels. According to their creation story, the Quileutes were changed from wolves by a wandering transformer. The story inspired Meyer’s writings and draws many “Twilight” fans to visit the tribe’s reservation.

“This would protect all the tourists, also,” Cleveland said.