Everything about the new St. Croix River bridge project will be big, from the price tag to extensive highway realignments in two states to four lanes of traffic towering over the water.
After decades of controversy that reached all the way to Congress, construction of the mammoth $676 million project begins in April with initial work on approach roads in Oak Park Heights.
"By mid-May there will be quite a bit of work on that corridor," said Jon Chiglo, Minnesota Department of Transportation (MnDOT) manager overseeing the project.
Heavy equipment and a flood of workers will appear, beginning four years of activity that will end an era dating to 1931, when the nearby Stillwater Lift Bridge opened. The project will transform the St. Croix Valley, diverting commuter traffic from Stillwater and creating a major highway through Oak Park Heights and eastward through lightly populated St. Joseph Township in St. Croix County, Wis.
"It's going to be part of a grander traffic management plan to allow a safer crossing on the St. Croix River," said Gary Kriesel, a Washington County commissioner representing Stillwater and Oak Park Heights.
Initial work will include clearing trees in a neighborhood that was abandoned in the 1990s to make room for the bridge approach. Rehabilitation will begin on a scenic overlook this spring, business frontage roads along Hwy. 36 in Oak Park Heights will be rebuilt and construction will begin this summer on five piers to support the bridge in the river.
Design of the bridge superstructure should be completed this summer, Chiglo said.
MnDOT also will open a construction office in Stillwater, a block north of the Greeley Street intersection with Hwy. 36. That office will be open to contractors and anyone else who has questions and concerns, Chiglo said.
Cost of the bridge portion is estimated at $293 million. The bridge will cross about a mile downriver from the Lift Bridge, which will become part of a 4-mile loop trail when it's retired from vehicle traffic.
Chiglo told the Washington County Board on Tuesday that MnDOT had secured most of the dozens of permits needed for construction.
"There's nothing surprising or alarming at this point," he said.
Several environmental groups, including the Sierra Club, opposed the project as being too big and costly and also damaging to the St. Croix River, a federally protected waterway. Congress approved an exemption to the U.S. Wild and Scenic Rivers Act a year ago and President Obama signed it into law.
The new bridge will stand more than two times higher than the Lift Bridge and more than three times higher than the Interstate 94 bridge to the south. It will start 110 feet above the river at Oak Park Heights and rise to 140 feet at Wisconsin.
Kriesel said the old age of the Lift Bridge and continuing traffic congestion in Stillwater as drivers waited to cross it made a new bridge long overdue. But he also said a new bridge will make the area more attractive to people who want to enjoy trails, Stillwater's downtown and other features.
"There are going to be a lot of tourists who come to see what the St. Croix Valley has to offer," he said.
Kevin Giles 651-925-5037 Twitter: @stribgiles