Myth: Clear Water Is Clean Water

Some parts of northern Wisconsin and Michigan are rugged landscapes dominated by boulders, gravel, and sand. These popular vacation areas have rivers and streams that are swift-flowing and appear clear, cool, and inviting.

But here in northern Illinois, our land surface is dominated by flat topography and fertile soils. Over the years as agriculture and urban development in the Chicago region progressed, the naturally slow and meandering stream flows were consolidated into faster-moving channels. The swifter currents erode soil along the riverbank and off the river bottom, and so the water isn’t always crystal-clear.

Yet despite these suspended soil particles, the river can still be “safe” and clean for many forms of recreation, and these waterways continue to function as important plant and animal habitat.

The Situation

The Chicago region is richly blessed with its vast network of streams and rivers. These waterways provide wonderful opportunities for recreation, and they also function as important plant and animal habitat.

But set within a landscape so dominated by human development, we’re often left to wonder some very logical questions about river water quality. Is it safe to paddle my canoe down the river or eat the fish I catch? Is the river safe for the herons and mink that I see along the shoreline? If the river water appears clear, does that guarantee that it’s clean?

The Problem

Streams and rivers are the drainage component of Nature’s plumbing system. They collect and convey rainwater that runs off our rooftops, lawns, parking lots, and roadways. Along the way, the flowing water may erode dirt from construction sites and other areas where there is bare soil. Most of us have seen the impacts of this land erosion when our rivers appear “murky” after a heavy rainstorm.

But after the storm subsides and the river water becomes clearer, there still can be other contaminants left in the water that, although invisible to our unaided eye, can have important environmental and public health impacts.

Lawn fertilizer nutrients like phosphorus and nitrogen remain dissolved in the river water, so while these compounds are generally not toxic to animals and humans, they can contribute to profuse algae blooms that cause rivers to become choked with algae.

There might be bacterial contamination from failing septic systems, leaky sewer lines, or large congregations of wildlife—but since the bacteria are so tiny and microscopic, their numbers could be dangerously high even though the river water appears clear.

The Solution

The environmental and recreational goals for many our region’s streams and rivers are to have water that is both clear and clean.

To help keep the water clear, certain management approaches are used to reduce the volume of storm water runoff as well as the amount of soil eroding from the land surface. For example, you’ve probably seen black fabric fences alongside roadway construction projects—when properly installed this “silt fence” slows rainwater runoff from the site and helps prevent soil from being carried to downstream rivers.

Or, perhaps you’ve seen restoration projects in your community that added deep-rooted native plants along a riverbank to keep the slopes from washing away during high flows.

And as we learned earlier, there’s more to a healthy river than just clear water—we also want to help keep the river water clean and free of contaminants. Most of our region’s wastewater treatment plants discharge to rivers, so making sure they’re designed and consistently operated at peak efficiency is a must. Since a portion of lawn fertilizers, herbicides and pesticides usually end up in rainwater runoff (and ultimately our rivers), these products should be applied carefully and only when needed.

Taking personal responsibility for seemingly even minor sources of water pollution can help as well. A good example is cleaning up pet waste: it’s loaded with bacteria and nutrients that can wash down the storm sewer and into the river.

What You Can Do

If you like healthy rivers with clear, clean water, here are some things you can do:

  • Cover Bare Soil: Keep areas of bare soil in your yard to a minimum. Consider adding native groundcover plants, or apply mulch products over the exposed soil.
  • Minimize Fertilizer Use: Apply lawn and garden fertilizers only if soil tests indicate a specific need. Did you know that most of our region’s soils have a natural abundance of phosphorus, so adding more phosphorus will not only not make your plants grow better…but that also the phosphorus-laden runoff may “feed” algae blooms in downstream rivers? In fact, just a few months ago Wisconsin effectively banned the sale of lawn fertilizers containing phosphorus.
  • Dispose of Household Chemicals Safely: Help your municipal wastewater treatment plant discharge the cleanest water possible. Many household chemicals and pharmaceuticals are not able to be removed by the treatment plant, so rather than flushing them down the drain, keep them out of our rivers by disposing of them properly. Learn more at Lake County Household Chemical Waste Collections and Solid Waste Agency of Northern Cook County, Household Chemical Waste Collection.
  • Compost Produce Waste: In the kitchen, consider composing your fruit and vegetable waste instead of pushing it down the garbage disposal. Why? Some of the waste’s nutrients aren’t removed by the treatment plant and so it ends up “fertilizing” our river instead. If composting isn’t an option for you, then throw all kitchen waste that had been destined for the garbage disposal in with your regular trash.
  • Support Urban Water Quality Policies: Support local ordinances and public policies designed to minimize the effects of urban development on river water quality. To start, check out the Metropolitan Water Reclamation District’s Cook County Stormwater Management Plan or the Lake County Stormwater Management Commission.
  • Research Your Local River:To learn more about the water quality of your favorite stream or river, visit the Illinois Environmental Protection Agency’s website.
  • Join a Water Protection Group: Consider becoming involved in river and watershed protection organizations. Take a look at the Prairie Rivers Network, the Metropolitan Water Reclamation District’s Watershed Planning Councils, or one of the Illinois Department of Natural Resources’ ecosystem partnerships that have assembled to protect our region’s waterways.

Written by Bob Kirschner, Chicago Botanic Garden