Endangered Mussels Delay Yorkville Bridge Project

YORKVILLE, IL -- The plan to replace the Eldamain Road bridge over Rob Roy Creek may be delayed due to an endangered species of mussels in the area, according to Kendall County officials. Kendall County Now (KCN) reported that the bridge, north of the Fox River and south of U.S. Route 34, was originally supposed to be replaced starting Aug. 4.

Because of the slippershell mussel's status as endangered, the bridge planners will need to include a conservation plan to "mitigate the disturbance of the mussel," KCN reported county engineer Fran Klaas as saying. The project is expected to be pushed back to Sept. 22.

The Checklist of Illinois Endangered and Threatened Animals and Plants report shows that in 2015, the mussels were only threatened, meaning they were susceptible to becoming endangered. The Prairie Research Institute at the University of Illinois at Urbana-Champaign said in its Illinois Natural History Survey, however, that they are now endangered.

Endangered species are "in danger of extinction in the wild in Illinois due to one or more causes including but not limited to, the destruction, diminution or disturbance of the habitat, overexploitation, predation, pollution, disease, or other natural or man-made factors affecting its prospects of survival," according to the Illinois Endangered Species Protection Board.

The mussels' endangered status could be due to several factors. Patch interviewed Dr. Phil Willink, the Senior Research Biologist at the Shedd Aquarium in Chicago, who said that typically, mussels "need clean [river] bottoms. If there's a lot of erosion, sediment could collect and suffocate them."

Willink said the most common remedy for such situations is to simply move the mussels. In building a bridge, "you damage the banks nearby, causing a lot of sediment that could travel downstream and impact sensitive habitats," he said, noting the care planners need to take when working situations like this.

The plan was to remove the metal culverts and replace them with a single-span bridge. "But the process of taking the culverts out and putting in the bridge has the potential to disturb or kill a mussel or two," Klaas said, according to KCN. The new plan is "going to take us some time and probably cost us a lot of money," he said, noting he wouldn't be surprised if it costs taxpayers tens of thousands.

But, "it's standard procedure," said Willink. Whenever a threatened or endangered species may be affected by government projects, "certain wheels go into motion," he said.

Article image via Illinois Natural History Survey, University of Illinois at Urbana-Champaign