The $16 million makeover of the historic Coon Rapids Dam is almost complete.
Crews are now finishing up replacement of the final gates that will shore up the century-old dam's structural integrity and ideally keep invasive carp from the upper reaches of the Mississippi River and the popular Lake Mille Lacs fishery.
The rehabilitated dam should be fully operational by early winter.
Crews have worked for two years replacing nine of 10 gates and are repairing one existing one. Old, inflatable rubber gates have been replaced with new, hinged metal ones. The new gates will stay in an "up" position year-round to keep invasive carp — known to leap 8 to 10 feet in the air when startled — from traveling past the dam.
The Legislature paid for the rehabilitation in large part to stave off the invasive fish species, which has been found as far north on the Mississippi as the Cottage Grove area.
Three Rivers Park District owns the dam, which maintains water levels to allow for boating and recreation in the upstream pool, but it's the Minnesota Department of Natural Resources that has overseen the massive rehabilitation.
Erosion of the riverbed near the dam also demanded attention, a DNR engineer said.
"It wasn't an emergency, but it was something that needed to be addressed fairly quickly," said Jason Boyle, a dam safety engineer overseeing the project for the DNR. "Three Rivers came to us and said we need to fix the dam."
