LAS VEGAS — Word that U.S. Interior Secretary Ryan Zinke is proposing to downsize Gold Butte National Monument in Nevada drew condemnation from environmentalist advocates and Democratic elected officials, but a measured cheer from the head of a southern Nevada water district with springs in the area.

Kevin Brown, general manager of the Virgin Valley Water District, said Monday that the boundary change his agency sought from Zinke covers about 25 square miles (65 square kilometers) in the Virgin Mountains. That’s about 5 percent of the overall monument area.

A memo from Zinke to President Donald Trump recommends an unspecified reduction of Gold Butte monument about 80 miles (128 kilometers) northeast of Las Vegas, along with size reductions of Bears Ears and Grand Staircase Escalante monuments in Utah and Oregon’s Cascade-Siskiyou monument. Two marine monuments in the Pacific Ocean would also be reduced.

“Our recommendation (to Zinke) was to just make the northern boundary of the monument match the water district’s southern boundary,” Brown, in Mesquite, told The Associated Press in a telephone interview. “Until it all plays out, we’ll be cautiously optimistic that something will be done to protect the water district resources up on the mountain.”

But the head of the nonprofit Friends of Gold Butte vowed a legal challenge of any boundary change by presidential edict.

“Our feeling is, any reductions by executive order would be illegal,” said Jaina Moan, president of the advocacy, activism and lobbying group based in Las Vegas. “We are ready to challenge the matter in court.”

Zinke’s memo to Trump noted the Mesquite water district’s “historic water rights” and that five of its six springs are now in the 464-square-mile (1,202-square-kilometer) national monument created last December by President Barack Obama.

Zinke recommended revising the boundary “through the use of appropriate authority, including lawful exercise of the President’s discretion … to protect historic water rights.”

While Zinke noted in the memo that presidents have reduced the size of 16 national monuments over the years, Moan said the Federal Land Policy and Management Act of 1976 shifted to Congress the authority to change the monuments’ boundaries.

Nevada Democratic U.S. Rep. Dina Titus said Monday that Mesquite water sources are protected by the Gold Butte monument boundaries. Democratic Reps. Ruben Kihuen and Jacky Rosen said the monument should not be changed.

Democratic U.S. Sen. Catherine Cortez Masto said the Trump administration was threatening more than a century of environmental protections guaranteed by the Antiquities Act of 1906, and noted that millions of comments were provided in recent months calling for national monuments to be protected.

Republican U.S. Sen. Dean Heller called creation of the monument an example of “overreach and the failed Washington-knows-best mentality.” He said he hoped Trump would agree with Zinke.

Zinke on July 30 toured parts of the Gold Butte and Basin and Range national monuments by helicopter, which combined, cover some 1,500 square miles (3,885 square kilometers) in Nevada.

Basin and Range was not recommended for reduction in the memo.

Elected Democrats and an Indian tribal leader criticized Zinke the following day for canceling meetings with advocates, while the Interior Department fired back with a statement calling critics’ claims “patently false.”

The agency said Zinke did all he could in Nevada after learning he had to shorten his trip for a Cabinet meeting involving top Trump appointees in Washington, D.C.

Moapa Band of Paiutes Tribal Chairman Darren Daboda complained at the time that Indians with cultural ties to the areas were treated “like second-class citizens.”

Daboda didn’t immediately respond Monday to telephone and email messages about the recommendation that Trump should ask Congress to let tribes “comanage” Gold Butte cultural areas.

“The management plan should be revised to continue to protect objects but also prioritize public access; infrastructure upgrades, repair and maintenance; traditional use; tribal cultural use; and hunting and fishing rights,” the Zinke memo said.