Yorkville Dam

Kendall County was established on February 19, 1841 and the government township 37 north, range 7 east plat was signed on August 25, 1842. Labeled on this plat are Howe's Mill Dam and a saw mill on the south side of the river. Surveys taken in 1837 and 1838 show there was a dam across the Fox River at Yorkville as part of a mill near the present dam location. Records indicate that the Yorkville mill buildings were destroyed by fire. In 1915 an old wood crib dam existed across the Fox River with a head race on the south side of the river.

The Glen D. Palmer Dam is located on the Fox River approximately 35.9 miles upstream of the confluence with the Illinois River. The dam is in the City of Yorkville 940 ft upstream of the Illinois Route 47 bridge and was a low overflow structure that had a modified ogee crest, with a spillway length of 530-feet, a height of 5 feet (as originally constructed), and a crest elevation of 575.0 M.S.L. The drainage area tributary to the dam is 1804 square miles.

The USGS has maintained a gage at Dayton Dam since 1914 and a gage at South Elgin Dam between 1989 and 1998. These gage records were used to synthesize a daily discharge record for Glen D. Palmer Dam for the 1914 to 2000 time period.

The Glen D. Palmer Dam at Yorkville, IL was first built in 1952 as a part of the Stratton Project Dam System, but over the years the flow of water eroded the riverbed creating a dangerous roller effect. The Division of Waterways under FR-121, constructed the present dam in 1960-61, named after a former Director of Conservation. Completion of the dam did not, however, include any riverbed protection below the dam.

In May of 1976, the Mayor of Yorkville wrote to the Office of Water Resources (OWR) requesting a site review because of drownings at the dam. In an attempt to remedy the situation in 1978, the OWR under FR-295 placed riprap in the scour hole downstream of the dam to reduce the scour hole and the effect of the under tow, and temporarily eliminated the roller as the next drowning was not until 1984.

In 1991, a survey of the spillway clearly showed that the riprap had since been scoured out by the plunging waters and a new scour hole had developed. In October of 1993 the Yorkville police department contacted the OWR to again request assistance. The police department reported that 26 people had lost their lives at the dam.

In 1996 a study was completed by the Hydrosystems Laboratory of the Department of Civil Engineering, University of Urbana-Champaign, entitled "Hydraulic Model Study for the Drown Proofing of Glen D. Palmer Dam, Illinois." The study looked at the causes of the scour hole and attempted to reproduce it by constructing sectional physical models. To add to the dam removal alternative, modified dam designs were developed to determine the best way to alleviate the safety problem at the dam. A total of five different structural alternatives were studied. It was found that a four-step spillway design was the most economical and appealing structural alternative.

An Executive Summary report was completed in 2004 to recommend the best method of improving hydraulic conditions at the downstream face of the dam, reconnect the river with respect to fish movement, and provide safe canoe passage through the dam site after recreational benefits were desired as well.

Alternative 2* was selected, including reconfiguration of the overflow spillway by the addition of reinforced concrete steps on the downstream face combined with the addition of a canoe and fish bypass adjacent to the south bank of the river and reservoir. Reconnection of the river allows for targeted fish movement in both upstream and downstream directions and passage of canoes in the downstream direction. The alternative provides a whitewater feature which serves as an attraction to whitewater enthusiasts. Also, this alternative preserves the water surface area upstream of the dam, used by water fowl and riparian land owners and a portion of relatively deep water used as winter cover by fish.

The conversion from an ogee dam to a stepped dam began in 2006 with completion date of 2010. A one of a kind 11,000 ft long dual bypass chute was designed as a canoe and kayak chute for both inexperienced and advanced kayakers and canoeists with two distinct routes, a moderate and a challenge route. Grouted boulders were used to shape the channels and create the flow necessary for simulating rapids found in natural rivers.

A pedestrian bridge was constructed in 2011 for public access to the divider island that separates the river from the canoe bypass and allows fishermen access to the dam and river area. A video of the bypass and river was taken to show the buoys in place.

A Denil fish ladder, the first of its kind in Illinois, was also constructed adjacent to the dam's north abutment.

One species of fish identified as threatened in the State of Illinois is known to occur in the Fox River. Considerations for this species, Moxostoma carinatum (river redhorse) have been noted within the alternatives selected for dam modification at the Yorkville site. None of the alternatives outlined is believed to negatively impact this species or contribute to its extirpation. Both dam removal and dam modification with bypass alternatives have the positive impact of mobility restoration. Dam removal was expected to have a slight additional positive impact of improving hot weather night-time dissolved oxygen concentrations in the area immediately upstream of the dam.

Another unique project feature is the application of planted riprap. A wet prairie seed mixture was applied to the channel slopes following construction and next growing season visitors should enjoy a diverse and colorful mixture of grasses, sedges, bulrushes, and forbs, including New England aster, joe pye weed, bonset, sunflower and blue flag iris.

ABC7 in Chicago aired a report on the new bypass channel in November 2012.