By JOHN FLESHER AP Environmental Writer

TRAVERSE CITY, Mich. (AP) — The Trump administration is revoking an Obama-era regulation that shielded many U.S. wetlands and streams from pollution but was opposed by developers and farmers who said it hurt economic development and infringed on property rights.

Even before the official announcement, scheduled for later Thursday, environmental groups blasted the administration's action, the latest in a series of moves to roll back environmental protections put into place under former President Barack Obama.

The Waters of the United States rule being revoked defines which waterways are subject to federal regulation.

"This action officially ends an egregious power grab and sets the stage for a new rule that will provide much-needed regulatory certainty for farmers, home builders and property owners nationwide," Environmental Protection Agency chief Andrew Wheeler and R.D. James, assistant secretary of the Army for civil works, wrote in a column published Thursday by the Des Moines Register.

Since enactment of the Clean Water Act in 1972, the federal government has gone beyond protection of navigable waterways and their major tributaries to assert jurisdiction over "isolated ponds and channels that flow only after it rains," the officials wrote.

"As the definition expanded, so too has Washington's power over private property and the states' traditional authority to regulate their land and water resources," they said.

President Donald Trump had ordered the agencies to develop a replacement policy that has a more restrictive definition of protected wetlands and streams, leaving fewer subject to federal protection.

Environmentalists say the move would leave millions of Americans with less safe drinking water and allow damage of wetlands that prevent flooding, filter pollutants and provide habitat for a multitude of fish, waterfowl and other wildlife.

The Natural Resources Defense Council said the Trump administration's action would be challenged in court.

"The Clean Water Rule represented solid science and smart public policy," it said in a statement. "Where it has been enforced, it has protected important waterways and wetlands, providing certainty to all stakeholders."

But Don Parrish, congressional relations director for the American Farm Bureau Federation, says the 2015 regulation that extended federal protection to many U.S. wetlands and waterways created uncertainty about where farmers could cultivate land.

"It would be great if farmers didn't have to hire an army of consultants and lawyers just to be able to farm," he said.

Republican Sen. Kevin Cramer of North Dakota says the Obama rule was "an unconstitutional power grab that did nothing to advance good water management."

The question of which waters are covered under the Clean Water Act has inspired decades of lawsuits and congressional debate.

A sharply divided Supreme Court in 2006 produced three differing opinions, leading the Obama administration to craft its rule. It provided federal oversight to upstream tributaries and headwaters, including wetlands, ponds, lakes and streams that can affect the quality of navigable waters.

The regulation drew quick legal challenges. Courts prevented it from taking effect in parts of the U.S.

Betsy Southerland, who was director of science and technology in EPA's Office of Water during the Obama administration, said repealing its regulation would create further regulatory confusion.

"This repeal is a victory for land developers, oil and gas drillers and miners who will exploit that ambiguity to dredge and fill small streams and wetlands that were protected from destruction by the 2015 rule because of their critical impact on national water quality," Southerland said.

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