VERNON HILLS, Illinois — Dams that have hindered the flow of the 133-mile-long Des Plaines River for more than a century are being removed to restore its natural flow, improve aquatic habitat and make the waterway safer for people who use it.
Scientists say the dams, many first built in the 1920s and 30s, have outlived their usefulness and are causing environmental problems along the river, which meanders from Wisconsin through northeastern Illinois, the Chicago Tribune reported Sunday (http://trib.in/1FIX6W9 ).
Six dams have been removed since 2011, and more are coming down, including two near Vernon Hills that will be removed this summer.
The barriers hurt water quality and limit fish migration, and cause safety hazards for paddlers and anglers. Removing them helps restore habitat for fish, insects and plants, experts said.
"All communities benefit even if they don't ever see the river ... everyone needs clean water. Everyone needs the benefits that rivers provide," said Jessie Thomas-Blate, associate director of river restoration at American Rivers.
The Des Plaines River once flowed freely through northeastern Illinois' prairies and forests. Then farmers began using the dams for irrigation or to cross the river before bridges were built. The dams also were built to mask the smell of raw sewage that was being dumped in the river, and some were built to eliminate mud flats and marshland.
The Des Plaines River dam removals mirror a nationwide trend, with 72 dams removed across the country last year.
Most of the dams removed from rivers and streams throughout the United States —971 of 1,185 dams — have been demolished in the last 20 years, according to the American Rivers database.
In northeastern Illinois, dams also are being removed on the Chicago and Fox rivers.
Once a dam is removed, it doesn't take long for the river to reclaim its natural path and, within months, plants that loves mud return to formerly submerged land along the river banks, said Rick Gosch, acting director of water resources for Illinois Department of Natural Resources.
Information from: Chicago Tribune, http://www.chicagotribune.com