Dams are Never Good for Rivers

 By Dennis Streicher

In 2004, the Illinois Environmental Protection Agency (IEPA) finalized and published its report on whether the three rivers in DuPage County were meeting the goals of the Clean Water Act (CWA). One of those reports was titled “Total Maximum Daily Loads for Salt Creek, Illinois” (TMDL). To anyone paying attention to this report, it was not a surprise that it (and two other reports on the East and West Branches of the DuPage River) declared that Salt Creek was not meeting the goals of the CWA. As part of the mandate from the United States Environmental Protection Agency (USEPA), Illinois had to find a way to bring Salt Creek into compliance with the CWA. The result was that IEPA proposed more strict limitations on publicly owned treatment works (POTWs) on Salt Creek. However, upon reading the report, it was apparent that the largest remaining impairments to the river were systemic, the results of decades of neglect by the communities bordering the river watershed--not an unusual situation in any place that is lucky enough to have a river in the neighborhood.

None of the insults on the river could be solved or removed by the POTWs. We needed a watershed-wide approach instead. At the time, I managed a POTW that discharged to Salt Creek. I and the managers of two other POTWs (one on the East Branch and the other on the West Brach of the DuPage) formed the DuPage River Salt Creek Workgroup (DRSCW). We studied the TMDL and took to heart one of the suggestions, that the Graue Dam at Fullersburg was the major cause of the dissolved oxygen (DO) impairment on Salt Creek. Our task was clear: the dam had to be removed if Salt Creek would ever get close to meeting the goals of the CWA.

The next 16 plus years were spent more closely studying all the stressors on the rivers in DuPage County. IEPA measures how close a river is to achieving the goals of the CWA by evaluating the diversity and number of vertebrates (fish) and invertebrates (insects) living in the river. They are, after all, the best indicators of the overall water quality and habitat of the river. Powered by a motivated and highly skilled staff, the DRSCW did habitat assessments and detailed chemical evaluations. Sediment oxygen demand studies were completed, and we made detailed evaluations of the fish and insects. The DRSCW identified several physical projects that would help improve the rivers. Some were completed and resulted in measurable improvements in the watersheds where they were done. Subsequent assessments of the biotic life and of habitat in the rivers also improved.

But on Salt Creek one key project still needed to be done. We had to reconnect the river to the larger watershed downstream. We had to remove the Graue Dam! Our studies show that there are 16 more species of fish downstream that could migrate upstream when the dam is removed. Aside from the physical barrier of the dam, the dam creates an impoundment of water that is in essence a dead zone, having low to no DO. The dam impoundment caused the development of a deep mucky sediment that results in a habitat of such low quality that virtually nothing can survive there, creating an impenetrable barrier to fish migration upstream, even if they could get past the dam. Dams are never good for rivers, and the Graue Dam is no different! The DRSCW has removed dams in other watersheds and monitored the fish movement afterwards. After the dams are gone, the fish reoccupy the new upstream areas surprisingly quickly, sometimes in a matter of weeks. This same scenario has occurred in other parts of the country when dams are removed.

In the end, the project will improve (even create) about 1.3 miles of good- to high-quality river habitat. There will be a pleasant rushing river with its sounds and sights for all to enjoy. In addition, the project will provide a canoe/kayak launch, added hiking trails, a couple of fishing platforms, and even a photography clearing that will allow the historical Graue Mill building to be used as a backdrop for wedding photos (a popular draw for the site). We will do this while honoring the historical nature of the area for the First Peoples who used the site and the European settlers who used the river resource, as well.

As I write this, the DRSCW is nearing the end of an effort that began back in 2007, when the first detailed DO studies were completed, showing just how damaging the dam and its accompanying water impoundment are to the river. The studies are complete, and public meetings have been held with overwhelming support for dam removal. The designs and permits are in place. Bids have been let, and a contract has been awarded. The project begins in late November 2023. It’s time to restore Salt Creek and take a major step to bring the river back to life.

Photo credits: Jeff Gahris and DRSCW