Two of the nation’s most scientifically significant landscapes — the Kaiparowits Plateau and Cedar Mesa — could be largely stripped of hard-won protections when President Donald Trump appears in Utah on Monday to announce major reductions to Grand Staircase-Escalante and Bears Ears national monuments, according to leaked documents obtained by The Washington Post.

The areas form the hearts of their respective national monuments, yet portions of them were targeted for removal under recommendations to Trump by Interior Secretary Ryan Zinke. After reviewing several large monuments across the U.S. earlier this year, Zinke concluded past presidents abused the Antiquities Act when they used the landmark conservation law to designate oversized monuments in southern Utah.

On his visit to Utah next week, Trump is expected to act on Zinke’s recommendations, which have never been disclosed outside a summary memo previously leaked to The Post. The newly leaked documents show how Utah’s two monuments could be broken into five, with tiny satellites to protect specific ruins, while stripping protection from 2 million acres of public lands.

Zinke also recommended shrinking two other Western monuments, Cascade-Siskiyou on the California-Oregon border and Nevada’s Gold Butte, and revising others to allow for some resource development.

News of additional details on Trump’s intentions for Bears Ears and Grand Staircase-Escalante drew hearty praise from many Utah officials, who have urged that they be scaled back or eliminated, along with harsh criticism from backers of the two monuments, including tribal leaders.

According to The Post’s story published Thursday, Bears Ears will be reduced 85 percent, from 1.35 million to 201,397 acres in the redrawn Indian Creek National Monument and Shash Jaa National Monument. The latter spans Mule and Arch canyons from Bears Ears Buttes to Comb Ridge and includes the distinctive sandstone fin south to the San Juan River. Shash Jaa is Navajo for Bears Ears.

However, Interior spokeswoman Heather Swift cautioned Thursday that The Post story was based on “very old and outdated information”

Yet the scenario described by the newspaper resembles Bears Ears boundaries for national monuments or conservation areas that had been suggested by Utah officials during Zinke’s review.

Messages left with leaders of the Utah-based anti-monument group Stewards of San Juan were not immediately returned Thursday. Locally elected leaders said they are planning a “thank you” rally at the Monticello courthouse Monday and planned to hold tickets for hundreds of residents so they can attend at the Utah Capitol when Trump is expected to make his noon announcement.

Pro-monument protests, meanwhile, are planned for Saturday at 1 p.m. inside the Capitol and outside or nearby Monday.

Cedar Mesa, home to tens of thousands of archaeological sites left by Ancestral Puebloans, would be largely excised from the monument, according to The Post’s report — although Trump’s draft proclamation calls for protecting two sites specifically named in President Barack Obama’s original Bears Ears proclamation: Moon House ruin on the mesa’s eastern flank and Doll House ruin far to the north in Dark Canyon. Both the popular locales would fall outside the contours of Shash Jaa monument, while House on Fire ruin would be within its boundaries.

“It is highly likely that at least three-fourths of the archaeological sites in the monument will be removed from protection. The most famous and most dense areas will not be in,” said Josh Ewing, executive director of Friends of Cedar Mesa. Archaeological sites — including free-standing masonry structures, granaries and ancient dump piles known as middens —are most concentrated on the mesa top, while the most famous sites, typically cliff dwellings, are tucked in the side canyons, such as Grand Gulch.

“Cedar Mesa is just the tip of the iceberg. There are less well-known areas on the flanks of the Abajos and in Beef Basin,” Ewing said. Also excluded would be Mancos Mesa, Valley of the Gods, White Canyon, Elk Ridge and Dark Canyon.

The 1.9 million-acre Grand Staircase-Escalante would be reduced by about half to 997,490 acres, and split into three separate monuments called, west to east, Grand Staircase, Kaiparowits and Escalante Canyons national monuments, according to the leaked plan. The Paria River would separate the Grand Staircase and Kaiparowits monuments and the Hole in the Rock road would separate the Kaiparowits and Escalante monuments

The revelation of Trump’s intentions with regard to Bears Ears brought swift rebukes Thursday from Native American and environmental groups already on edge in anticipation of the Republican president’s trip to Utah.

“It shows that this administration doesn’t understand the reasons or the places or the connections of native people to this landscape,” said Gavin Noyes of Utah Dine Bikeyah, the local Navajo nonprofit that had began developing the monument proposal years ago.

“You can’t diminish something to such a great extent and ignore all the reasons people asked the area and the things within it and connections within it to be protected,” Noyes said.

The Bears Ears monument proposal was also championed by governments from five tribes, which formally petitioned Obama to designate a 1.9 million-acre monument. Late last year, Obama complied by declaring a smaller monument and giving the tribes a special advisory role in monument management.

Tribal leaders said any reduction to Bears Ears would be immediately challenged in court.

“It’s appalling that one could think it’s not worthy of continued protection,” said former Ute Mountain Ute tribal council member Regina Lopez-Whiteskunk, now vice chair for Western Leaders Network. “Shrinking the boundaries does not truly represent a well-balanced effort to find a solution.”

Environmentalists argue Trump’s move to strip protection from the nation’s most culturally significant wildlands would be illegal, lead to the ruin of archaeological sites and wildlife habitat and harm local businesses.

“No one will look back on this decision in 15, 25 or 50 years and say Trump did the right thing by protecting less of these magnificent places,” said Steve Bloch, legal director for the Southern Utah Wilderness Alliance. “And by promoting this illegal act, Utah’s parochial congressional delegation and local politicians have firmly come down on the wrong side of history.”

But supporters of Trump’s approach, who argue that the Staircase monument has strangled economic development in Kane and Garfield counties for the past 21 years, say these lands already are layered with other bureaucratic protections that will ensure precious resources remain secure.

Trump’s move to reduce the monuments is welcome news for Utah’s political leaders, who praised Zinke’s review as a fair process that will lead to a balanced solution and a win for partisans on all sides.

“The details of the president’s announcement are his and his alone to make, but I appreciate his willingness to listen to my advice and, even more importantly, to give the people of Utah a voice in this process,” Utah Sen. Orrin Hatch said in a statement.

Added Rep. Rob Bishop: “Utah has become ground zero for politically motivated national monument designations that are excessive in size and contemptuous of peoples’ livelihoods. The president has stood against prior abuses of executive power and his administration has demonstrated a commitment to work in concert with local communities to protect unique public antiquities and objects the right way.”

According to Hatch, Trump had promised him he would open the Kaiparowits Plateau’s vast coal deposits to mining. But much of the plateau, which also holds the world’s most complete record of Late Cretaceous fossils, would remain as a national monument, according to the map obtained by The Post.

Reporter Thomas Burr contributed to this report.