A wetland and marsh area at Chain O' Lakes State Park. Illinois' Interagency Wetland Policy Act of 1989 set a goal of no net loss of wetlands due to projects funded by the state. (GoodFreePhotos.com)

A U.S. Supreme Court decision is shaking up the environmental community in Illinois and across the country.

The high court ” target=”_blank”>ruled 5-4 on Thursday that wetlands areas are not protected by the federal Clean Water Act, except in limited cases. Conservation groups have said the decision could put up to 80% of wetlands in the nation at risk for pollution and development.

Sierra Club Illinois director Jack Darin pointed out that wetlands absorb flood water, filter drinking water and provide shelter to a rich variety of wildlife. He said the primary protection for these areas in Illinois is the Clean Water Act.

“Today, the Supreme Court struck down that part of the Clean Water Act,” he said. “Now, our people and our wildlife are unprotected and it’s really critical that our state and our local governance step in to this gap to protect these areas that are so important to our health and our communities.”

The court’s ruling gutted what is known as the “Waters of the United States” rule, which has been under attack by industry and some private landowners for providing Clean Water Act protections they believe are too broad. The ruling came in a lawsuit by an Idaho couple against the EPA for not being able to build on their land because it contained wetlands.

Darin said Illinois has already lost more than 90% of its wetlands areas, which largely have been converted to farmland. He’s convinced the rest are now at risk.

“We have seen a sustained assault on the Clean Water Act from polluters and developers that want to be able to destroy the last of our wetlands,” he said, “and they have aligned with the conservative majority on the court.”

According to the U.S. Geological Survey, about 3.5% of Illinois is wetlands.