A federal judge ruled Friday that a snowmobile route near the Boundary Waters Canoe Area Wilderness does not violate the Wilderness Act.

Environmental advocacy groups have been in a legal battle with the U.S. Forest Service since 2006 over its plans to dedicate a snowmobile route in northeastern Minnesota.

The groups — Izaak Walton League of America, Wilderness Watch, Sierra Club Northstar and Northeastern Minnesotans for Wilderness — said the route would impact sound quality in the tranquil setting of the BWCA.

Judge John Tunheim said in an opinion filed in U.S. District Court in Minneapolis the proposed snowmobile route does not violate federal law.

"Ultimately, the most any wilderness visitor will hear due to (the proposed route) is sound equivalent to moderate rainfall," he wrote.

Additionally, impact will "only occur in a small portion of the affected wilderness."

The proposed South Fowl Snowmobile Trail would run through the Superior National Forest adjacent to the BWCA.