President Donald Trump will shrink the Grand Staircase-Escalante National Monument by about half, to a size between 700,000 and 1.2 million acres, following the recommendation of his Interior secretary, according to a staffer for Sen. Orrin Hatch.

Ron Dean, Hatch’s central and eastern Utah director, revealed the potential magnitude of monument reductions Tuesday while fielding questions from the Utah Legislature’s Commission for the Stewardship of Public Lands.

He also confirmed Bears Ears National Monument will be redrawn in the range of 100,000 to 300,000 acres when the president visits Utah early next month. It’s currently 1.35 million acres.

But Dean cautioned, absent changes to the Antiquities Act that rein in alleged abuses, any monument reduction could be fleeting since afuture president could reverse whatever action Trump takes.

“We are going to get a pingpong effect should the president lose and the wrong kind of occupant of the White House, who has a different view of what public lands in the West are all about, they could restore Grand Staircase and Bears Ears,” Dean said. “There is a substantial fear that, especially in Bears Ears’ case, it would be even be larger than originally called for by President Obama.

Trump’s action to reduce Utah’s two monuments will be based on recommendations by Interior Secretary Ryan Zinke, whom the president instructed to review 27 large monuments designated mostly by Presidents Bill Clinton and Barack Obama under the Antiquities Act.

In a leaked memo, Zinke did not recommend revoking any monuments, but he did urge the president to reduce Grand Staircase, Bears Ears and two other Western national monuments. His specific recommendations, however, remain under wraps despite widespread calls for their release to the public.

“The fact that we’re learning as much about the president’s review fromSen. Hatch as we are from the White House shows that the realdecisions about these monuments are being made in secret,” said Chris Saeger, executive director of the Western Values Project.

At Tuesday’s meeting, Sen. Jani Iwamoto, D-Salt Lake City, said she makes a point of speaking with local residents and businesses whenever she visits Garfield and Kane counties. People often tell her they would prefer Grand Staircase remain in tact because the monument protects so many natural wonders that draw visitors.

“It has helped them greatly economically and their way of life,” Iwamoto said.

But Kane and Garfield county commissions see the monument as a drag on their economy and heritage and have implored the federal government to break it into a few small monuments, focused on places that truly warrant preservation instead of vast landscape sprawling from Skutumpah Terrace to Glen Canyon.

Dean said he has not seen Zinke’s proposed monument changes, but was confident the acreage ranges he provided are accurate.

“If [Trump’s] announcement is outside those parameters, my rumors are bad rumors,” said Dean, arguing that presidents have authority to adjust monument boundaries proclaimed by predecessors.

“There have been multiple instances of monuments being enlarged or shrunk, sometimes in substantial ways,” he said.

Dean’s report to state lawmakers is based on what Trump has told Hatch, one of the Senate’s most powerful members, whose support would help the president advance his legislative agenda regarding tax reform and financing a wall along the Mexican border.

Earlier this week, Zinke told The Salt Lake Tribune he counseled the president to severely reduce Bears Ears, but keep it bigger than Bryce Canyon and Arches national parks combined. That means at least 180,000 acres.

Zinke’s recommendations are expected to align with what state and local leaders requested for the two Utah monuments. For a reduced Bears Ears, Utah officials drew a 120,000-acre oval stretching from Bears Ears Buttes to the Butler Wash ruin and submitted the map to the Interior Department.

Proposals for a redrawn Grand Staircase were left to Kane County leaders. They presented their map while meeting with Zinke on May 10, during the secretary’s multi-day swing through Utah, according to County Attorney Robert Van Dyke. Yet the county has rejected The Tribune’s public records request for that and many other maps it prepared in its push to reduce the 1.9-million-acre monument Clinton proclaimed as he was running for re-election in 1996.

That map indicated two areas local officials believe would be appropriately protected as national monuments, according to Van Dyke’s presentation at the State Records Committee Nov. 9, where he tried to fend off The Tribune’s appeal. One would be the Escalante Canyons in Garfield County, and the other would be a slice of Kane County between Paria and Cottonwood washes.

Dubbed “Heart of the Monument” because the outline is shaped like a heart, this area is just south of Kodachrome Basin State Park and includes Hackberry Canyon, but leaves out numerous world-class hiking destinations as well as much of Kaiparowits Plateau, which holds abundant coal deposits.

The Record Committee found that the county had properly classified the maps as protected drafts, but ordered the one shown to Zinke and several other maps be released, concluding that disclosure served the public interest. The county has until Dec. 9 days to contemplate an appeal to district court.

Correction: Nov. 15, 8:15 a.m.: An earlier version of this story misstated the size of the reduction that a staffer of Sen. Orrin Hatch expects for Grand Staircase-Escalante National Monument. He said he expects the monument to be trimmed to a size between 700,000 and 1.2 million acres.