Crews will have to move thousands of mussels in the St. Croix River as part of the bridge project connecting Minnesota and Wisconsin.
The Milwaukee Journal Sentinel reports the more than 7,000 mussels will include three species that are protected or endangered and that play an important role in the river's health.
The Wisconsin Department of Natural Resources' mussel expert, Lisie Kitchel, says divers will take the mussels upstream next summer. She expects the effort to cost about $50,000.
The St. Croix Crossing project will replace the 80-year-old Stillwater Lift Bridge with a four-lane bridge that will connect expressways on both sides of the St. Croix River.
According to estimates by Wisconsin and Minnesota officials, the project is expected to cost $580 million to $676 million.