The U.S. Army Corps of Engineers has given the Minnesota Department of Transportation its approval to build a new four-lane bridge over the St. Croix River.

Late last week, the agency issued a permit that will allow the department to build the superstructure that will connect Oak Park Heights with St. Joseph, Wis. south of Stillwater.

The permit includes two authorizations under the federal Rivers and Harbors Act and the Clean Water Act. Both authorizations were required because the construction involves work within the St. Croix River, a navigable water of the United States, and wetlands.

Known as the St. Croix Crossing, work on the bridge that will replace the 80-year-old Stillwater Lift Bridge will begin this spring and take about three years to complete.

The project, which will cost between $580 million and $676 million, also includes reconstructing and realigning Hwys. 95 and 36, realigning intersections at Oakgreen Avenue and Greely Street, adding a bike and pedestrian trail and constructing noise and retaining walls.