is pressing ahead with a massive overhaul of his department, despite growing opposition to his proposal to move hundreds of public employees out of Washington and create a new organizational map that largely ignores state boundaries.
Zinke wants to divide most of the department's 70,000 employees and their responsibilities into 13 regions based on rivers and ecosystems, instead of the current map based mostly on state lines.
The proposal would relocate many of the Interior Department's top decision-makers from Washington to still-undisclosed cities in the West. The headquarters of some of its major bureaus also would move to the West.
The concept — supported in principle by many Western politicians from both parties — is to get top officials closer to the natural resources and cultural sites they manage. The Interior Department oversees a vast expanse of public lands, mainly in the West, that are rich in wildlife, parks, archaeological and historic sites, oil and gas, coal and grazing ranges.
It also oversees huge dams and reservoirs that are vital to some of the West's largest cities and most productive agricultural land.
Rep. Raul Grijalva of Arizona, the ranking Democrat on the House Committee on Natural Resources, suspects the plan is an attempt to undercut the department by pressuring senior employees to quit rather than relocating, leaving positions unfilled and creating confusion about who regulates what.
"I think it's a very thinly disguised attempt to gut the Department of Interior and its bureaus," he said.
Grijalva also questioned the value of moving more department employees West, saying more than 90 percent are already in field offices outside Washington.
Grijalva and Democratic Rep. Donald McEachin of Virginia, also a member of the Natural Resources Committee, on Wednesday accused Zinke of withholding key information from lawmakers and trying to implement the plan piecemeal while avoiding full scrutiny from Congress.
Congress has the final say over the proposal.
And a bipartisan group of Western governors complained to Zinke two weeks ago that he shut them out of the planning for the reorganization. The Republican-dominated Western Governors Association expressed concern that organizing the department around natural features instead of state lines would weaken their states' influence on department decisions.
Zinke's spokeswoman, Heather Swift, said Wednesday that moving more Interior Department employees to the West has received overwhelming backing from Congress and state governments, and that managing by ecosystems, instead of state borders, has "a lot of support."
Six Republican members of the House Natural Resources Committee told Zinke last month they support the reorganization. They said it would improve agency efficiency and responsiveness.
The Interior Department has been unusually tight-lipped about the plan and has not said how many of its Washington-based employees would be moved, where in the West they would land, when they would go, or how much the overhaul would cost.
Swift said the department has briefed both Republican and Democratic congressional staffers and state officials on the proposal. She also said the department does not have a final plan.
But the agency has already compiled a tentative map of the new regions, provided to The Associated Press by the Western Governors Association. And budget documents released Monday show the department is already taking steps to implement it.
The department requested $17.5 million in 2019 to get the plan started and to move an undisclosed number of employees from their Washington headquarters to the West.
The budget documents included only a broad outline of the proposal and did not address in detail how it would affect the department's basic responsibility — managing natural resources.
In an email to the AP on Wednesday, Swift said boundaries based on rivers and ecosystems would allow resource managers to do a better job and coordinate more closely because nature doesn't follow political boundaries. She used a deer herd as an example.
"In just one season alone, the herd might pass through a national park, state land, a wildlife refuge and private land — and along its migration, it could wander through two or three different states," she said.
Zinke has compared his proposed regional boundaries to the ideas of John Wesley Powell, a famed one-armed Civil War veteran and Grand Canyon explorer. Powell argued — unsuccessfully — that Western state boundaries should be drawn along river systems, not arbitrary survey lines, because of the importance of water in the largely arid region.
Donald Worster, an environmental historian and author of "A River Running West: The Life of John Wesley Powell," said Zinke's plan bears only a faint resemblance to Powell's.
"Powell had a very clear definition of the 'problem' his map was supposed to fix," Worster said in an email to the AP. "Zinke is far less clear."
Zinke's tentative map lumps together some very different areas and divides others that have features in common, Worster said. Zinke also treats river systems and ecosystems as the same things, but they are not, he said.
"His patched-together and conceptually muddled maps do not encourage one to hope that real science will be given more visibility and authority in the (Interior Department)," Worster said.
Lynne Scarlett, who was deputy secretary of interior under President George W. Bush, said the reorganization could cut both ways.
Focusing on large, regional ecosystems could help the department pay more attention to the connections among land, water, wildlife and people, said Scarlett, now a policy executive for The Nature Conservancy. But the department's bureaus have different and very specialized responsibilities, and it's important to preserve their individual missions, she said.
"There's no perfect management solution. Every solution that one thinks about involves trade-offs," she said.