An Obama-era clean water regulation maligned by Georgia farmers and land developers is being rolled back by the Trump administration, a move environmentalists say could harm nearly 40,000 miles of streams in the state.

Local supporters of Trump's replacement "Waters of the United States" rule say it will cut down on burdensome red tape from Washington. Under the rule's previous incarnation, which was blocked by a federal court, landowners said they were required to secure federal permits for routine operations such as building small structures or using pesticides near drainage ditches or other minor bodies of water on their properties.

The updated rulemaking, which was finalized last week and will go into effect this spring, now distinguishes between navigable waterways — which fall under the jurisdiction of the Clean Water Act and are illegal to pollute without a permit — and certain wetlands, intermittent and “ephemeral” streams created by rainfalls.

That means major bodies of water like the Chattahoochee River and Carters Lake near Ellijay will still be regulated, said Mary Walker, administrator for the U.S. Environmental Protection Agency’s Southeast region, and smaller or underground sources like groundwater, farm water ponds and wastewater treatment systems will not.

The Trump administration’s new rule is “clear, appropriate and legally defensible,” Walker said at an event Tuesday at the Georgia Department of Agriculture.

“States like Georgia already have a robust network of regulations that protect their state waters, and this rule outlines an approach that together with existing state and tribal regulations provides a network of coverage to protect our nation’s waters as called for by the Clean Water Act,” she said.

Environmentalists warned that President Donald Trump’s rulemaking would give heavy industry and developers more leeway to dump pollutants, harming drinking water, wetlands and the state’s most iconic bodies of water.

“If you’re concerned about the Chattahoochee River, you need to be concerned about what’s flowing into the Chattahoochee River,” said Blan Holman, who leads the Southern Environmental Law Center’s Clean Water Defense Initiative.

“It’s kind of like saying we care about keeping our heart healthy but we’re not going to concern ourselves with what’s in the bloodstream and the arteries and the veins.”

Holman said the Trump administration’s new regulation goes farther than repealing President Barack Obama’s rule — it chips away at protections for wetlands and ephemeral streams that have been in place for decades.

The group Environment Georgia previously estimated that nearly 40,000 miles of the state’s streams, or roughly 57%, could be adversely affected.

Trump has made repealing his predecessor's environmental legacy a top order of business at the EPA. He rolled back Obama's signature climate plan in 2018 and has also chipped away at rules regulating chemicals and endangered species.

Among the local groups that voiced their support for the scaled back water rules was the Georgia Farm Bureau, which described the Obama-era guidelines as "needlessly complex."

“We’ve got a lot more certainty than we had before,” Jeffrey Harvey, the group’s director of public policy, said Tuesday. “Before, we didn’t really know which (water) features were considered ‘waters of the U.S.’ and which ones weren’t.”

Cheering on the new rulemaking with Walker at Tuesday’s event were two of the state’s top elected officials, Attorney General Chris Carr and Agriculture Commissioner Gary Black.

Carr made fighting the Obama administration rule a top priority shortly after he was appointed in fall 2016, joining a group of mostly red states that successfully sued to block the regulation in court.

“What the past rule did was basically take away the state’s ability to protect our own natural resources,” Carr told The Atlanta Journal-Constitution. Georgia has “a great history of protecting our natural resources, and we will do it in the future.”