The Trump administration has thrown out Obama-era rules that expended federal protection of waterways from pollution, a move environmentalists say they will challenge in court.

Getting rid of the 2015 Waters of the United States Act "puts an end to an egregious power grab, eliminates an ongoing patchwork of clean water regulations, and restores a longstanding and familiar regulatory framework," Environmental Protection Agency Chief Andrew Wheeler said Thursday.

He added that it fulfills one of President Donald Trump's "key promises."

Wheeler made his announcement at the Washington headquarters of the National Association of Manufacturers, whose members have been lobbying against the clean water regulations.

The WOTUS rule protected wetlands and streams from pollution by pesticides, mine waste and fertilizers. It solidified what waterways fell under the landmark 1972 Clean Water Act.

Opponents of the Obama administration rules say the regulations created confusion, and likened them to a federal land grab of private property. Farmers and others complained the act also applied to small ponds that do not flow anywhere, leaving them wondering whether they could work their land without violating federal law.

Wheeler says the EPA will now redefine which waterways are subject to federal regulation.

Planned lawsuit

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Environmentalists say they will take the EPA to court. They said Thursday that throwing out the 2015 rule means unsafe drinking water, a higher risk of floods when wetlands are destroyed and less wildlife habitat.

"The Clean Water rule represented solid science and smart public policy," the Natural Resources Defense Council said Thursday.

Betsy Southerland, a top EPA official during the Obama years, calls the repeal a "victory for land developers, oil and gas drillers, and miners." (VOA)