In 2023, the U.S. Supreme Court upended federal protections for America's wetlands.

The 5-4 decision in Sackett v. EPA redefined a protected wetland under the Clean Water Act, stripping protections for many of the nation's marshes, lakes and streams. Environmental advocacy groups and regulators have spent nearly two years trying to understand the full scope of the decision.

Now, a new report from the Natural Resources Defense Council, a nonprofit advocacy group, offers a look at which South Carolina wetlands might have federal protections stripped away. The NRDC estimates that, under the "most damaging" interpretation of Sackett, more than 1.77 million acres of South Carolina's wetlands could soon lack federal Clean Water Act protections. That's about three-quarters of the government-regulated total.