The two remaining dams on the Des Plaines River in Lake County will be removed in an effort to restore the waterway into a more free-flowing channel.
Farmers long ago installed the dams as a convenience, but the action being pursued by the Lake County Forest Preserve District is expected to increase the number and type of fish and wildlife and make the river safer for recreational use, the district said.
Dams in two forest preserves, MacArthur Woods near Vernon Hills and Captain Daniel Wright Woods near Lincolnshire, were found to "fragment" the river by restricting the movement of fish and other organisms. They also pose potential safety hazards to canoeists and others, according to the district.
A sheet metal dam at the Ryerson Conservation Area near Deerfield was cut into pieces and replaced with boulders and rocks in early 2011. It was the first of three dams the district wanted out to improve fish habitat, enhance safety and reduce flooding upstream.
Known as low-head dams, the concrete structures at MacArthur and Wright Woods are 2 to 3 feet high and front a 25-foot-wide concrete apron that spans the river. They were thought to be installed more than 70 years ago.
"The farmers used to use them to cross the stream," said Jim Anderson, the district's natural resource manager. "They put them in way back when." Removing what are now considered obstacles is part of a larger effort.
Last fall, Gov. Pat Quinn announced the Illinois Dam Removal Initiative to remove 12 dams on the Des Plaines and Chicago rivers that have no benefit to plants or animals or the people who use the waterways. Dam removals on the Des Plaines also are recommended in a U.S. Army Corps of Engineers study, Anderson said.
"These definitely are goals the feds have, the state have and we have," he said.
The Illinois Department of Natural Resources will pay the district up to $750,000 to have the dams removed.
On Monday, the forest board's planning and restoration committee recommended the district enter into an agreement with IDNR to accept the funds and also to award a contract for $109,500 to Wills Burke Kelsey Associates Ltd. of St. Charles for engineering services associated with the projects.
The district's finance committee will consider the items on Thursday, and the full board will consider them Sept. 10.