EMPIRE, Mich. (AP) — Federal prosecutors filed misdemeanor charges against a man who is accused of diverting a river within Sleeping Bear Dunes National Lakeshore in northern Michigan.

Authorities last August described a “dramatic shift” at the mouth of the Platte River as it meets Lake Michigan in Benzie County. MLive.com said a channel was cut, likely with shovels, a condition that could make it easier for boats to get to the lake.

Andrew Howard, 62, of Frankfort was charged Tuesday with tampering and vandalism. A message seeking comment wasn’t immediately returned Wednesday.

“The Sleeping Bear Dunes National Lakeshore and the Great Lakes are national gems, and my office takes preserving our natural treasures very seriously,” U.S. Attorney Mark Totten said.

The state Department of Natural Resources had federal approval to dig out the river mouth but stopped about five years ago, MLive reported.