FAQ

The Master Plan for Salt Creek will be funded by the DuPage River Salt Creek Workgroup (DRSCW).  The DRSCW is a not- for-profit 501(c)(4) formed in 2004 working to improve the water resources of the Salt Creek, East Branch DuPage River, and West Branch DuPage River watershed in Cook and DuPage Counties.

Membership includes 26 Waste Water Treatment Plants (WWTPs); 38 municipal entities (DuPage County, cities, forest preserves, park districts) as well as environmental advocacy groups and environmental consulting firms.  Since 2005, the members of the DRSCW have implemented targeted projects and programs that cost effectively worked towards the goals of the Clean Water Act.

The Forest Preserve District of DuPage County (FPDDC) owns the Graue Mill dam, the historic Graue Mill, and all land and amenities in the Fullersburg Woods Forest Preserve. The DRSCW will need to obtain permission from the FPDDC to construct the proposed project.

Removing the Graue Mill dam will save taxpayers approximately $200 million dollars.  If the proposed project is not implemented, local waste water treatment plants (WWTP) will be required to upgrade their plants at a cost of $213 million.

Removing the Graue Mill dam and enhancing the stream corridor will cost approximately $5 million – this budget is already held by DRSCW so the Master Plan will create no additional costs to taxpayers. Removal will eliminate expenses associated with maintenance and safety repairs on the dam and expenses associated with aquatic life protection.

The DRSCW is not proposing the project simply to escape WWTP upgrades. Scientific studies prepared by the DRSCW and the Illinois Environmental Protection Agency have found that these proposed upgrades WILL NOT solve the water quality, habitat and fish passage problems caused by the Graue Mill dam. It is safe to assume that if the WWTP go ahead with these expensive upgrades, it will only delay the need to remove the dam.  The $213 million cost of this delay will be paid by taxpayers in the form of utility bill increases.

The mill will remain as it is now. The removal of the dam does not necessitate any alteration to the millhouse itself. In an effort to preserve the spirit and historical importance of the site, options have been discussed to use some of the project budget to improve landscaping in the area of the millhouse and surrounding area. Placing an independent source of water in the millrace is under investigation and will be explored with the Mill’s operators. The plan is also looking for input on informational signs around the area, restoring the impoundment to native wetland, and building recreational structures like a boat launch, trails and fishing areas for visitors to enjoy.

Removing dams provides benefits to wildlife, river health, and human activity. Fish are unable to cross dams and subsequently are trapped in sections of the river. This leads to stretches where fish are removed from food resources and spawning habitat and can lead to loss of species and large sections of river devoid of multiple species. If dams are removed, fish will reestablish themselves in suitable areas. In Salt Creek, affected fish include several important game species such a northern pike and rock bass.

Aquatic invertebrates are also affected, suffering from altered habitat and degraded water quality, which contribute to an unbalanced ecosystem in the river.

Removing the dam will restore the native habitat in the river by restoring flowing water and reducing sediment buildup. Erosion increases downstream of dams, so removing it will help stabilize the streambed downstream and save money on infrastructure and damage.

Dam removals have been proven to improve water quality, reduce algae blooms and make the river cleaner for those who use it. Dams cause drops in dissolved oxygen, which aquatic organisms need to breathe and survive. An extreme example of lack of dissolved oxygen is the gulf hypoxia issues (also called dead zones) in the Gulf of Mexico.   In the case of the Graue Mill Dam, dam removal will offset expensive upgrades at upstream Waste Water Treatment Plants.

Removing the dam also removes a dangerous obstruction for paddlers and allows continuous navigation of the river. Restoring the water quality, river habitat and subsequent diversity of fish, invertebrates and other animals will increase fishing and wildlife viewing opportunities as well.

Dam removal will restore the river to a more natural, free flowing state, which changes local conditions. For example, the impoundment will be eliminated and replaced with a flowing river. These changes are beneficial for the environment and wildlife though some people may prefer the site in its current state.

The removal process can also stir up sediments, damaging spawning grounds and habitat. Precautions will be taken prior to and during removal of the Graue Mill dam to mitigate any potential impacts for sediment within and downstream of the project site.

The Master plan includes planting native vegetation on bank areas that will be exposed once the river resumes its natural flow. With the removal of the dam, the impounded area, roughly 16 acres, will shrink, leaving behind a flowing river exposing an area that was previously covered with stagnant water. These areas will be immediately planted to create a natural riparian zone, an area of vibrant native plants and flowers that provide valuable habitat for birds, butterflies and other wildlife. In addition to increasing habitat, this riparian zone will enhance bank stability and reduce erosion.

No. Removing the dam will not increase flooding either upstream or downstream. As it stands now, the dam plays no part in flood mitigation or management. Our project design is required to show no increase in post-project flood elevation to meet DuPage County’s strict permitting standards.

The easiest way to illustrate how Salt Creek will look is to look at the river downstream of the dam or near Rainbow Bridge within the Fullersburg Woods Forest Preserve.  Our analysis indicates that post-project Salt Creek will vary between 70 and 100 feet wide throughout the project corridor. And just like the portions of Salt Creek upstream and downstream of the Graue Mill impoundment don’t dry up in the hot, dry summer months, neither will Salt Creek within the Fullersburg Woods Forest Preserve.  Salt Creek will continue to flow year-round in its newly established channel.

No.  Data from dam removals show conclusively that the diversity of fish and insects increase following dam removals.  Dams alter the natural physical, biological and chemical functions of rivers and streams and often result in unsustainable and degraded conditions for a variety of aquatic and land species. Removing the dam will restore Salt Creek to its natural riverine condition and provide better quality habitat for fish, amphibians, dragonflies, damselflies, and birds.  Additionally, the riparian and wetland vegetation that will be enhanced as part of the project are also the preferred habitat of many desirable species such as turtles, frogs, songbirds, and shorebirds.

Rivers are very dynamic and resilient systems. Experience has shown that natural river systems can be restored relatively rapidly after dam removal. For example, after the removal of the Churchill Dam on the East Branch DuPage River in 2012, nine (9) species of fish including the johnny darter and channel catfish, who were only previously observed downstream of the dam, were observed upstream of the former dam location only months after the dam was removed.   At the Preserve at Oak Meadows, it took only four (4) years after the removal of the dam and completion of the 1.5-mile-long stream restoration for habitat and macroinvertebrate to improve from fair to good and excellent condition and in compliance with state water quality standards.

The active construction period is expected to last no more than 3 months. The dam removal and stream restoration project will be constructed during low-flow conditions in either the spring or fall of 2022/2023.  At the end of the active construction the site will be fully stabilized with no mudflats or disturbed areas remaining.  Following active construction, there will be 3-5 years of vegetation management including plantings, weed control, and mowing.

No. The dam present on Salt creek near Graue Mill is not the original dam. The dam at the site was constructed in 1935 by the Civilian Conservation Corp. The dam was built after the mill had been abandoned on the approximate location of the original dam which had washed away.

The current dam/raceway (the diversion works to bring a controlled flow of water to the water wheel and back to the river) configuration is not adequate to supply a reliable flow of water to the wheel.  While the wheel is in good working condition, flow in the race way is weak and intermittent. The crib and plank dam that was used when the mill was a commercial enterprise would have been considerably taller allowing a predictable flow in the raceway.  An additional issue is the deposition of debris in the raceway, which further weakens the flow.

In summary, under certain conditions (high river flows and a clean race way), the flow can turn the water wheel.  However, the water wheel is not connected to the mill’s internal gearing and given the current configuration of the dam would be unlikely to generate enough power to turn the gearing even momentarily.  However, the mill does not rely on the water wheel for internal power as the internal gears and millstones are turned by an electric motor.

The mill will remain as it is now. The removal of the dam does not necessitate any alteration to the millhouse itself. In an effort to preserve the spirit and historical importance of the site, options have been discussed to use some of the project budget to improve landscaping in the area of the millhouse and surrounding area. Placing an independent source of water in the millrace is under investigation and will be explored with the Mill’s operators. The plan is also looking for input on informational signs around the area, restoring the impoundment to native wetland, and building recreational structures like a boat launch, trails and fishing areas for visitors to enjoy.

Nationwide, 1,722 dams have been removed from 1912 through 2019 including 90 dams in 2019. Four have been carried out in DuPage county (McDowell Grove Dam, Warrenville Dam, Churchill Woods Dam, and Oak Meadows Dam) with another 18 in the bordering counties (Kane, Kendall, Cook, Will).⁽¹⁾ DRSCW has documented water quality and wildlife improvements at these sites following dam removals.

Click here to learn more about and see photos of dam removal projects in Northeastern Illinois.

⁽¹⁾American Rivers. 2020. Raw Dataset— ARDamRemovalList_figshare_Feb2020. Figshare. Available: https://doi.org/10.6084/m9.figshare.5234068
Retrieved: 2:18pm, 6/10/2020

According to a study by the University of Wisconsin-Madison on the impact of small dam removal on property values, “residential property located in the vicinity of a free-flowing stream is more valuable than identical property in the vicinity of a small impoundment” and “shoreline frontage along small impoundments confers no increase in residential property value compared to frontage along free-flowing streams.”