DNR divers move river mussels

Several species relocated upstream from bridge site

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About 4,000 native mussels like the ones shown here were recently relocated from the St. Croix Crossing river work zone by Minnesota DNR divers. Among the mussels moved included rare Higgins eye mussels. (Submitted photo)

More than 4,000 native mussel species — including some rare Higgins eye mussels — were recently relocated from the St. Croix Crossing work site by divers with the state Department of Natural Resources.

Divers spent two weeks relocating the mussels as part of preparations for bridge pier foundation work. The work could have threatened the mussels habitat on the river shorelines.

With the mussels relocated, crews from pier foundation contractor Edward Kraemer and Sons are working on the pier 12 foundation closest to the Wisconsin shore due to the rising St. Croix River level, according to Jennifer Wiens, a state Department of Transportation spokewoman.

“It’s something we take into consideration,” she said of the rising river. “Folks are watching it to see if there are any issues. The contractor was working on pier eight and stopped working on pier eight because of the high water.”

“The recent weather we’ve had has caused a nuisance,” said Project Manager Jon Chiglo Tuesday at the Oak Park Heights City Council meeting. “If we have big storms through the summer like we had this weekend, things could get problematic.”

MnDOT contracted with DNR divers for the mussel relocation after several rare mussels were found in the construction area last fall.

The work involved locating, identifying and tallying each distinctive mussel species. Divers crisscrossed a 75-foot by 400-foot area along the Wisconsin side of the St. Croix River to locate mussels. Crews documented and etched a number into the shell of each Higgins eye mussel found. DNR divers will check on the relocated mussels in about one year to assess how they survived the move.

“At this point, we have no reason to believe that any mussels died as a result of relocation,” Wiens said.

The Higgins eye mussel is on the federal Endangered Species list and recovery efforts for the species have been in place since 1972, when federal funds for the mussel’s protection and recovery were first appropriated.

Protection of mussels is one of several environmental and historical mitigation projects that are part of the overall crossing project. The St. Croix River is considered one of the most important and biologically diverse refuges for native mussels in the United States.

The mussel relocation was done as work continues in the river on pier foundations 9 and 12 closest to the Wisconsin shoreline.

“Moving into July, you should see more and more activity on the river,” Chiglo said.
Buoys designating the bridge work zone and narrow channel are in place along both shorelines, and a no-wake zone is in effect for project safety and equipment stability, according to MnDOT.

MnDOT officials said the city of Stillwater dock area north of Sunnyside Marina is an active construction zone and pedestrian access through this area is prohibited. The agency asks pedestrians not to use the area trail.

Other project work includes start of construction on the Minnesota 36 south frontage road extension east of Phil’s Tara Hideaway Restaurant; opening of the temporary Beach Road bypass to Stagecoach Trail; lane closures on MN 36 and Minnesota 95 for construction-related work, and continued land clearing east of MN 95. That work is expected to be finished early next week.

“You’re seeing more activity along Highway 95. There’s progress being made,” Chiglo told the Oak Park Heights council Tuesday. “The visual aspects of the project will be a little less inviting in July. Most of the work will be wrapped up in November.”

Project work hours are 7 a.m. to dusk Monday through Saturday. Some future projects might include overnight work, according to MnDOT.

Contact Erik Sandin at erik.sandin@ecm-inc.com

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