Safety At Dams

The IDNR Office of Water Resources (OWR) manages the Dam Removal program in Illinois.  This includes providing technical assistance and/or funding to government entities interested in improving safety around the dams which may include restoring the natural function of the river.  The OWR has developed a guidance document for local governements having a run of the river dam within their jurisdiction.  This guidance document is linked below:

Dam Removal Guidance Document

If a local governement is interested in the program, they should send a email containing a request for assistance on official letterhead to wes.cattoor@illinois.gov.  The OWR will follow up by scheduling an inital coordination call.    Further direction about the general process of the project is explained in the guidance document.  Assistance will be prioritized as follows:

1. State Owned Dams of Public Water
2. Publicly Owned Dams on Public Water
3. Publicly Owned Dam on Non-Public Water
4. Privately Owned Dams will not be considered.

Public Safety

The run-of-river dams are also dangerous to the public. There are dangerous currents under the surface of the water on the downstream side of the dam that can trap and capture people who go over the dam and capture/trap users that approach the dam from the downstream side.

Water Quality

Run-of-river dams degrade the quality of water by creating a stagnate pool of water that has diurnal fluctuations in dissolved oxygen that is conducive to large algal blooms.

Aquatic Habitat & Fish Passage

The run-of-river dams are harmful to aquatic habitat by both creating a barrier to the free movement of fish and mussels in an upstream direction and the poor water quality in the pool upstream of the dam.

Reduced Costs

A dam comes with many expenses including inspections and reporting, maintenance, rehabilitation, rescue training, insurance and potential litigation.

Recreation

Dam removal allows a continuous water trail for paddling enthusists and removes the burden of portaging around the structure. 

Will dam removal cause the river dry up?

This depends on the stream and not on the dam.  Run of River Dams do not change how much flow is occurring in the river.  Larger rivers such as the Fox River have constant flow, or base flow, throughout the year.  Therefore they will not dry up.  Smaller tributaries may only flow following rainfall events.  In this case, the area behind the dam may be dry during dry times of the year.

Will the area turn into smelly mud flats?

Sediment in rivers found near banks or other areas often contain native seeding that when dried due to the removal of the dam, begin to become vegitated shortly after.  Sand and gravel are not suitable material for vegetative growth.  An odor is typically not present due to dewatering the pool.  

What will be the impact on fishing?

If you fish at the downstream face of the dam, you may find that fishing may not be as abundant after removal as the fish will no longer be trapped in this area. Our fish monitoring has shown substaintial increases quantity of fish and variety of species in the former pool and throughout the connecting waters.  

How much will the water level drop after removal?

This is dependant on a number of condition including how much flow is in the river, how close to dam are you and how tall was the dam.  This can only be evaluated with river survey and engineering computations, though some estimates can be provided.

The low head Armitage and Fairbanks Dams on the Des Plaines River have been removed for ecosystem improvements and safety considerations.

The Armitage Dam spillway was 110 feet long, constructed of reinforced concrete, with an adjacent 5.5 foot wide boat portage at the west abutment. The dam crest was approximately five feet above the dam apron. The dam apron and supporting abutments remain in place. Armitage Dam was located in the Cook County Forest Preserve within River Grove, IL. , Armitage Dam was removed in late 2011 and early 2012.

Small dam on Des Plaines River north of River Forest will be history by mid-October - OakPark.com

Fairbanks Dam was 158 feet long and constructed ox xxxxxxxx and was shaped like a peaked roof., Cross sectional dimensions were approximately two feet by two feet. At the north bank, the dam was joined to the bank by a stepped concrete wall where three of the five steps of this stepped wall were removed as part of the dam. Fairbanks Dam was located between the Village of Riverside, Illinois and the Town of Lyons, Illinois in Cook County., Demolition began on January 31st, 2012 and ended a week later.

Riverside bids adieu to Fairbank Dam - Riverside - Brookfield Landmark

The Blackberry Creek dam (owned by the Yorkville-Bristol Sanitary District) fragmented Blackberry Creek and the Fox River by creating a barrier that denied fish and other aquatic organisms, including threatened species, access to quality habitat upstream of the dam. The dam blocked Fox River fish and microinvertebrates access to 32 miles of spawning and rearing habitat in Blackberry Creek that would provide increased fitness, distribution, and diversity of fish and microinvertebrates in Blackberry Creek and the Fox River.

The west abutment of the dam developed a large diagonal crack that allowed movement of this abutment such that failure of the dam abutment was imminent, potentially resulting in a massive head cutting and uncontrolled release of large quantities of sediment into Blackberry Creek and the Fox River, and the potential loss of a public bridge immediately downstream of the dam.

The timeframe for the removal of this dam was accelerated due to the rapid deterioration of an abutment that the dam shared with a county road. Phase 1 of the removal project involved notching the dam by two feet to lower upstream pool stages, wetland mitigation and construction access roads. Phase 2 involved complete removal of the dam and upstream channel restoration, main channel sediment excavation, and stabilization. The project was completed in Summer 2013.

The Office of Water Resources and Forest Preserve District of Cook County removed Dam #1 and Dam #2 on the Des Plaines River in August 2014 and reconnected nine miles of river for fish and recreational users. These roughly five-foot tall dams were owned by FPCC and removed as part of a broader restoration effort that will eventually involve removal of five additional dams between Wisconsin and Joliet, Illinois. Restoration of the Des Plaines River began in 2010 with the removal of the Ryerson Woods Dam. Since then, a total of six dams have been removed.

The Yorkville Dam has completed stepped spillway modifications and The new Marge Cline Whitewater Course at Yorkville is now open to the public free of charge. A Phase 3 pedestrian bridge will begin construction across the whitewater course later this year.

Renovation of the Glen D. Palmer (Yorkville) Dam was implemented to reduce public safety hazards at the dam, provide the opportunity for fish passage, and provide safe canoe and kayak boat passage through the dam with opportunities for white water boating recreation.

Initial attempts to reduce the dangerous scour roller effect that had developed at the dam were attempted in the 1970's with some success. Further attempts and studies resulted in the modification of the Dam in 2011.

To improve the ecological integrity of the dam site and fishing on the Fox River, the Yorkville Dam modification bypass is intended to encourage migration of local fish species by providing fish passage near both abutments of the dam via a Denil fish ladder and the bypass channel. This Denil is the first of its kind in the mid-west.

Large boulders and planted riprap along the perimeter of chutes and pools were included in the bypass design along with space between pool bottom boulders to replicate a natural channel and provide cover and protection to juvenile fish during higher flow conditions.

The bypass channel includes two whitewater challenge routes adjacent to the principal boat passage route with 7 chute or riffle sections and 7 pools and a continuous paved portage trail designed for experienced and novice paddle boaters. The channel's standing waves, drop and eddy channel features are characteristic of a Class 3 whitewater channel, with a safe slope for novice paddle boaters.

Members of the Illinois Paddling Council (IPC) and the Chicago Whitewater Association assisted the Department during construction and testing to share observations, and to identify potential whitewater boating hazards and concerns.

IDNR and the United City of Yorkville are continuing to work with the USGS to install a permanent USGS gage at the site to monitor river stages above and below the dam, and in the bypass channel.

The DNR Office of Water Resources and Teng & Associates (now ESP, Inc.) received the Illinois ACEC Illinois Engineering Excellence Honor Award and the prestigious Grand Award in the American Council of Engineering Companies (ACEC) 2012 Engineering Excellence Awards (EEA) for the project "Yorkville Dam Safety Improvements & Bypass Channel". Teng & Associates was IDNR's principal consulting design engineer for the project.

The first dam at the Hofmann site was built in 1827 upon a natural waterfall formed by a limestone shelf, also known as the Riverside Ford. The dam powered the first sawmill of Northeastern Illinois but made of simple timber construction, was short lived.

In 1866, the Fox Brothers purchased the site and established a grist-mill with a stone and timber dam in the shape of a horseshoe that lasted 31 years.

In 1907, the dam and surrounding properties were purchased by George W. Hofmann Jr. in order to create Niagara Park along the banks beside the dam.

In 1908, an improved horseshoe dam with a concrete base and wooden struts atop matching the height of the Fox Dam was built, comprised of a section of a larger superstructure connecting it with the Hofmann Tower and platforms on either side of the Des Plaines.

The pool behind the dam which had been used for recreational purposes began to be used as a sewage outlet for the city leading to the Sanitary District of Chicago building a by-pass at the Hofmann dam in 1928 along the north bank of the river in order to divert the trapped sludge and sewage when the unhappy owner refused to open the dam flood gates.

Between 1930 and 1933 additional improvements implemented above the Hofmann dam resulted in dispersal of approximately 4 feet of sludge from behind the dam. In 1936 the Works Progress Administration (WPA) removed the failed wooden crest atop the concrete dam which effectively lowered the dam’s crest and headwaters. The WPA also constructed a retaining wall on the riverbank of Swan Pond at this time.

The now notched dam was constructed by the State of Illinois in 1950 following much public concern over the crest level. Eventually, a concrete dam was erected in a straight line spanning the entire width of the Des Plaines with a crest level at 25.56’ equal to the heights of the prior dams of wood or partial wood construction.

Certain concrete walls lining the river, original to Hofmann’s design, were removed or reconstructed in 1950. Additional aspects of Hofmann’s design including the retaining walls east of the Tower on the south bank were removed in 1984. The only original elements of Hofmann’s design remaining today are the wall and boat docks on the south bank of the river west of Hofmann Tower and the Tower itself.

Construction is completed at Hofmann Dam at Riverside, IL. A drainage culvert was installed in Swan Pond with a culvert 3 or 4 feet tall and 10 to 15 feet wide and an asphalt walking path. 32 new trees have been planted in the park. The channel is now 5-6 feet deep in the narrowest part with a chokepoint of 15-20 feet wide.

Hofmann Dam was notched to permit greater fish passage and safer recreation opportunities. Two older dams behind Hofmann Dam were discovered and removed, one remaining from 1908 and one rock crib style dam from before that time.

Fish testing by the IDNR Division of Fisheries shows that there are now 20 species of fish living above the now-notched dam, and in far greater numbers.

The low head Winnetka Dam on the Skokie River/North Branch was removed for ecosystem improvements and safety considerations.

The Winnetka Dam Spillway crest was 44 feet in length and ranged in height from 2 to 3 feet above the dam apron., The dam was constructed of steel sheet piles with a concrete cap 1.5 feet wide and 1.0 foot high., The dam spillway, apron, and abutments were all removed., This dam was owned by the Forest Preserve District of Cook County., Winnetka Dam was removed in 2015.

The Forest Preserves of Cook County (FPCC) owns seven low-head dams on the Des Plaines River and North Branch Chicago River. These dams were built between 1918 and 1968 for recreation, transportation, and sanitary waste purposes. In addition, these dams were identified to be causing a decline in habitat quality by altering normal river hydraulics and hydrology within the river channel and its adjacent floodplain, while deterring the natural recolonization of fish. Based on this, FPCC is partnering with the Chicago District of the U.S. Army Corps of Engineers (ACoE) and the Illinois Department of Natural Resources (IDNR) to remove or modify these seven dams. Dempster Avenue Dam was constructed around 1942, and scheduled for removal in Fall 2016.

The series of locks and dams on the lower Des Plaines and Illinois River are only partial barrier to fishes, and over the long term do not prevent the intermingling of subpopulations above and below; however, these structures do cause impairment to riverine natural dynamics, instream hydraulics, instream habitat and floodplain habitats. The implementation of the removal of the last five dams on the upper Des Plaines River would essentially connect the headwaters to the Mississippi River.

Daily Herald: Lake, Cook counties to remove 3 dams along Des Plaines River, August 7, 2016

Evaluation of Public Safety at Run-of-River Dams, July 2007.

Part 1

Part 2

Dam Safety Poster