The Des Plaines River in Lake County was interrupted by three old low-head dams that had been built back in the 1930s or earlier by farmers to create pools for fishing or watering crops or for farm vehicles to cross the river to reach fields on the other side. Below you see the dam that is visible from the bike trail bridge in Dan Wright Woods. Four times I paddled the Des Plaines River Canoe Marathon and had to negotiate the dam with canoes and kayaks. If you look closely, you can see a "V" notch cut in the concrete which I used uneventfully each time, but craft that missed the notch had problems.The dam is 140 feet long, two to three feet high, and 25 feet wide.
Since the dams are no longer necessary and in fact disrupt river travel by fish and invertebrates, they are being removed. The Ryerson Dam was removed in 2013 and ecological improvements are already being seen, such as small bass sightings upriver. Also, silt will no longer accumulate behind the dams.
Below is a photo I took on 9/24/14 from the same bike trail bridge, after work had begun on the removal process. But pilings were discovered under the water and the projected had to be re-engineered and bids re-let. Then with Illinois' financial difficulties, the funding was cancelled and work halted.
Kudos to Lake County! Realizing the state may never again fund the removal of the remaining two dams, Lake County has decided to foot the bill ($690,000) even though they may not be repaid eventually by the state.
So here's the work resuming. I took this photo from the same bridge yesterday. The concrete that had been on the right side of the photo (eastern half of the river) is gone and work is proceeding on the west side now.
The Illinois EPA and Illinois DNR will work with the forest preserve district to sample the river for three to five years after the removal. It will be interesting to see how Mother Nature reclaims her own along the waterway!