How Illinois Watersheds Shape Water Quality

We all live in a watershed.

“What we do within those watersheds affects nearby streams, rivers and lakes, and in the case of most of Illinois, eventually the Mississippi River and the Gulf of Mexico,” says Erin Bauer, research projects coordinator and Section Lead of the Water Impacts for Society and Environment Section at the Illinois State Water Survey.

A watershed, sometimes called a drainage basin, is an area of land that channels rainfall, snowmelt and runoff into a common body of water such as a creek, wetland, river or lake. “Anything picked up by flowing water, whether dissolved, like road salt, or solid, like fine silt particles, will be transported through the watershed to the next river and ultimately to the oceans,” Bauer says.

This includes natural debris such as leaves and sediments such as soil and sand, as well as man-made pollutants. “When water moves more slowly overland, the soil and vegetation can absorb and filter out some pollutants,” Bauer explains.

But when it flows over solid surfaces such as rooftops, parking lots, streets and sidewalks, the water moves much faster, causing water levels to rise more quickly, leading to flooding, increased erosion and other issues.

“Think about cleaning your driveway,” she explains. “You don’t turn the hose on to a slow trickle. You use a strong flow of water, often with a sprayer, because higher pressure moves more dirt. Water in nature, in streams and rivers, works the same way. The faster it flows, the more solid materials it can carry. When water moves slowly, it picks up far fewer sediments and pollutants, allowing more time for the water to absorb into the ground.

“It’s important to know which watershed you live in because the choices we make every day can affect the water quality for our neighbors downstream,” Bauer continues. “Streams, lakes and rivers aren’t just scenery. They’re living ecosystems that support wildlife and often provide the drinking water for our communities. When a water supply faces challenges, we can usually look upstream within the watershed to find the source of the problem.”

McHenry County Watershed Volunteers

As a board member of the Boone-Dutch Creeks Watershed Alliance in McHenry County, Sue Jensen of Woodstock has been learning and teaching others about watersheds for years, along with many other conservation endeavors. The alliance is one of many in Illinois where volunteers and local water quality experts work to protect watersheds.

“In McHenry County, all the water from our watersheds drains into aquifers and the ground, and that’s where we source our drinking water,” Jensen says. “That’s why everyone needs to take care of their land to maintain high water quality.”

“What seeps into the ground where I live will end up in Boone Creek, which will eventually flow into the Fox River and then the Mississippi,” she continues. “If the soils in my watershed are filled with chemicals and don’t have native plants along the way to filter them, it will cause problems in the creek and beyond.”

What goes into the Mississippi River flows into the Gulf of Mexico. Watershed contaminants such as excess nutrients have created a dead zone of more than 5,000 square miles in the Gulf of Mexico. Excess nutrients cause an overabundance of algae, which die, decompose and deplete oxygen from the water. In turn, fish die, impacting tourism and the fishing industry. Illinois and other states are working to address the water-quality issue in the Gulf of Mexico. They search for places in various watersheds that could be contributing to the dead zone and find ways to slow and filter the water.

The Boone-Dutch Creeks Watershed Alliance has been documenting the rise of chloride content in the creeks within the watershed. Alliance members think the chloride is coming from road salt and water softeners in nearby neighborhoods. “Once salt gets into these native natural ecosystems, they cannot function properly,” Jensen says.

In addition, fertilizer and pesticides used in lawns and gardens end up in the creeks, too. “It’s all connected,” says Jensen, who espouses reducing lawn space in yards and replacing with native plants and trees.

Watershed Education in Action

Education is part of the alliance’s goal. For example, Jensen says, “We teach residents about sensible salting. We’re not saying you can’t use salt, but it works more effectively when you use less.”

Other ways to improve water quality include purchasing and protecting native ecosystems, such as Boloria Meadows, which was purchased by the alliance and is now managed by the Land Conservancy of McHenry County.

“The area has high-quality native plants and ecosystems that are protecting our water system,” Jensen says. “These plants help clean the water before it gets recharged back into the water table. We need to slow the water flow down. When water goes too quickly through your environment, it doesn’t have time to do what it’s naturally supposed to do.”

The alliance also schedules restoration and cleanup days, inviting local residents to join in—for example, scattering native seed or removing invasive plants.

Spring Creek Cleanups

“In spring, we have cleanup in various parts of the watershed before all the plants start growing,” Jensen says. For several springs, volunteers have been clearing trash that blows off a grocery store parking lot into Boone Creek. Recently, an alliance member talked to a shopping center owner that was willing to help with cleanup and put up fencing to keep trash out of the creek. “Sometimes just talking to people can work wonders,” Jensen says.

The alliance also stopped a proposed solar farm from being built right next to Boone Creek. “We felt it would damage the sensitive ecosystem and they ended up not building there,” Jensen recalls. Now the group is opposing a potential gravel pit expansion, which Jensen says could damage the watershed.

Rain Gardens and Green Infrastructure

Bauer says state and local governments, along with watershed alliances, encourage installing rain gardens, green roofs, bioswales and rain barrels to slow water flow and filter potential pollutants.

Bauer says homeowners can direct their downspouts into rain barrels or build rain gardens filled with native, water-loving plants. “Both options help capture and store rainwater, reducing runoff after storms while also creating a beautiful outdoor space,” she says.

“In addition to reducing the amount of pollutants that enter our watershed, any action that slows down or reduces the water flowing into streams and rivers after a rainstorm helps decrease runoff and improves water quality for your community and for everyone living downstream,” she adds.

Other activities include creating bioswales between streets and parking lots, with permeable pavers that slow the water. Morton Arboretum, in Lisle, and various area forest preserve districts have established permeable parking areas and bioswales, which filter stormwater before it flows into the nearby rivers and streams.

“All these projects make a difference,” Bauer says. “Every little thing you can do helps.” She adds that the watershed movement in the region has been active for a few decades.

Jensen says she believes people are becoming more aware of watersheds and using native plants in their gardens. 

“At a recent seed and soil event at McHenry Community College, we were astounded and thrilled with the hundreds and hundreds of people who were collecting native plant seeds to bring home to their gardens,” Jensen says.

Sheryl DeVore has written six books on science, health and nature, as well as nature, health and environment stories for national and regional publications. She is co-author of an upcoming book, Birds of the Midwest, to be published by Timber Press. Learn more at
SherylDeVore.WordPress.com.

Watersheds Near and Far

Watersheds cover the entire world and come in all shapes and sizes. In the continental United States alone, there are 2,110 watersheds. Within these are smaller watersheds, all connected to rivers, lakes and other bodies of water. The Illinois Natural History Survey has divided Illinois into 33 major watershed basins, which are further divided into smaller hydrologic units for managing water quality. The state is primarily part of the larger Mississippi River basin, with smaller portions draining into the Great Lakes watershed.  

One of the largest Chicago region watersheds, the Des Plaines River, covers 1,455 square miles in northeastern Illinois and southeastern Wisconsin. It begins near Union Grove, Wisconsin and flows south through Lake, Cook and Will counties in Illinois. The river joins the Chicago Sanitary and Ship Canal, in Lockport, and flows west through Joliet, before converging with the Kankakee River to form the Illinois River. The Illinois River then flows into the Mississippi River, which flows south to the Gulf of Mexico. 

How Residents Can Help Protect Local Watersheds

Dispose of leaves and other landscape debris properly, keeping it off the street.

Minimize use of lawn fertilizers, pesticides and herbicides.

Minimize salt use on driveways and sidewalks.

Pick up after pets and dispose of properly.

Use native plants in landscaping and reduce lawn size.

Install a rain barrel at a downspout to collect water for later use.

Residents can learn which watershed they live in and whether an alliance exists to help protect it at StoryMaps.arcgis.com/stories/abd2e65c1a304c2b9c69e2ebf109c3e8.