“So that means it can include streams and creeks that aren’t the Mighty Mississippi River, but that are important to the local communities that rely on them,” Griffith said. She estimates the new law will affect at least 640 miles of waterways across the state.

Griffith said there are errors in the state’s public waters inventory, which was created in the 1980s when the technology used to identify drainage areas was less advanced. The new law includes $8 million over the next eight years for the DNR to update the inventory. 

Some farm groups are concerned the new law could expand legal protections to more waterways and create uncertainty for farmers. Public waters have more regulations, including restrictions on draining and filling, and requirements to maintain vegetative buffers.

Pierce Bennett, public policy director for the Minnesota Farm Bureau Federation, called it “a pretty dramatic expansion” of what could be labeled public waters, leaving farmers “in a little bit of limbo.”

“Our view is that this would allow for a lot of waters that aren’t currently under that inventory to just simply be put in,” Bennett said. “And that is concerning.”

He said farmers shared their concerns about the bill with legislators throughout the session, and plan to work with state regulators to understand its impacts.

“We need to have a greater understanding of what this might mean for the future,” Bennett said.