The changes, finalized Jan. 23, scale back the government’s interpretation of which waterways qualify for protection against pollution and development under the nearly half-century-old Clean Water Act, potentially impacting roughly half of the nation’s remaining wetlands. That revision comes on the heels of a state legislative measure approved in 2018 that diminishes environmental protections for Michigan’s shrinking wetlands.

While the Trump rollback is set to take effect within about 60 days, environmental groups vow court challenges, perhaps delaying its implementation.

The rollback fulfills a promise by Trump to overturn an environmental rule put in place in 2015 by President Obama that expanded the bodies of water subject to federal protection.

That rule — which Trump termed “destructive and horrible” — stirred up considerable opposition from farmers, developers and fossil fuel producers, who currently must apply for a permit to discharge pollutants into protected waterways or to fill in wetlands.

The stakes for Michigan in this environmental battle are considerable. Over the decades, the state lost more than 50 percent of its wetlands, which are critical wildlife habitats and fish nursery grounds. Scientists consider wetlands vital to water quality, because they help control flooding, absorb stormwater runoff and help filter out pollutants.

The 1972 Clean Water Act authorized the federal government to regulate the discharge of pollutants into “navigable waters,” according to the U.S. Environmental Protection Agency. Under Obama’s revised rule, that was expanded to include smaller, upstream waterways and wetlands.

Under the Trump revisions, temporary bodies of water — those that form only after rainfall or flow only part of the year and dry up at other times — are now exempt from federal protections. This exception also applies to waste treatment systems, groundwater, converted cropland and farm watering ponds.

Taylor Ridderbusch, Great Lakes organizer for Trout Unlimited, a national conservation advocacy group, estimated the rollback could ease protection for nearly 20,000 intermittent streams in Michigan. Ridderbusch said these streams — which flow just part of the year — are nonetheless a crucial source of food and important breeding ground for trout and other fish.

“The impact on these streams could be huge,” he said.

“You would be able to plant crops in those stream beds that are intermittent. And if the fertilizer on that is going to go anywhere, it is going to be washed down that system,” he said.

The new rule retains federal protections for large bodies of water, as well as larger rivers and streams that flow into them and wetlands that lie adjacent. But critics of the Trump changes say the new rule goes beyond curtailing the 2015 Obama action by also eliminating protections for smaller headwaters and wetlands that have been in place for decades.

Farmers appreciate the clarity

Paul Pridgeon farms 4,500 acres of corn, soybeans and wheat in Hillsdale County, just north of the Indiana border.

“I’m very much in favor of this revised rule,” he told Bridge Magazine. “Any time I can get a clear regulation, I’m very much in favor of that.”

Pridgeon said he, like many farmers, feared that he might unwittingly break federal law under the former regulations just through normal farming practice.