WASHINGTON: US President Donald Trump's administration has revoked an Obama-era waterway regulation in a move condemned by conservationists but celebrated by farmers and developers.

It is the latest move from the president to boost the economy, frequently at the expense of the environment, while fulfilling promises made to his base in the 2016 campaign.

The waterways will be governed under a previous agreement until the end of the year, when the Environmental Protection Agency (EPA) is expected to adopt rules that define far more narrowly which waterways should be protected.

Environmental groups called the decision -- announced on Thursday -- to repeal the 2015 Waters of the United States rules (WOTUS) "shameful and dangerous."

Former president Barack Obama's WOTUS made the majority of American waterways subject to federal regulation, requiring landowners to get permits before they could develop or pollute lakes or rivers and -- environmentalists argued -- protecting delicate water systems from human damage.

But EPA chief Andrew Wheeler labelled Obama's regulations "an egregious power grab" and said at a press conference in Washington his department's changes were a return to "a longstanding and familiar regulatory framework."

Environmental groups warned the repeal would threaten drinking water, increase the pollution of streams and wetlands, and limit measures that reduce flooding.

Former EPA director of science and technology Betsy Southerland told the Associated Press: "This repeal is a victory for land developers, oil and gas drillers and miners."

But Republican Senator John Barrasso -- chairman of the Senate Committee on Environment and Public Works -- welcomed the change and said Obama's regulations "put backyard ponds, puddles and prairie potholes under Washington's control." —AFP