Maine’s four members of Congress signaled opposition to a Trump administration proposal to increase entrance fees during the peak season for visitors at Acadia National Park.

U.S. Sens. Susan Collins and Angus King as well as U.S. Reps. Chellie Pingree and Bruce Poliquin have promised to review Secretary of the Interior Ryan Zinke’s proposal.

Zinke seeks to start charging new entrance rates, called peak season fees, next year at 17 of the most popular national parks to attack the National Park Service’s $11.33 billion maintenance backlog.

Maine’s congressional delegation said that the fees might be too steep. The steepest would increase Acadia’s weekly vehicle pass from $25 to $70 between June 1 and Oct. 31.

“We are not certain that this [fee increase] would either solve the problem or outweigh the risk to the local community of making the park more difficult to visit,” Collins and King wrote in a letter released Friday.

The backlog cannot be ignored, said Poliquin, a Republican representing northern Maine. Fixing it should be part of a broader plan, said Pingree, a Democrat who represents southern Maine.

“Solely raising user fees is not the way to do it,” Pingree said in a statement.

The plan would set peak season seven-day entrance fees at $70 per private, non-commercial vehicle, $50 per motorcycle and $30 per person on bike or foot.

Acadia would continue to charge its current weekly rates — $25 for per private, non-commercial vehicle, $20 per motorcycle and $12 per person on bike or foot — during off-peak times.

Acadia currently charges $50 for a 12-month pass. The new proposal would raise that to $75 annually. The current $80 fee for an annual pass allowing entry to all national parks would not change.

The new rates would generate $70 million nationally, a 34 percent increase over the $200 million in revenue generated in 2016, the park service’s 100th birthday, Zinke said. The park service began seeking public comment on the idea on Tuesday.

Acadia’s maintenance backlog was $71,029,341 as of Thursday. About 87 percent of the park’s traffic — a record-setting 3,303,393 visitors in 2016 ― comes at peak time, said John Kelly, Acadia spokesman.

Federal law requires 80 percent of all entrance fees be spent where they are collected.

A breakdown of Acadia’s entrance-fee revenues and new-fee revenue estimates were not available. Park staff would need a lot of time, and more money, to handle all the repair work at once, especially since most of it would occur during the peak period, Kelly said.