True or false: the Chicago River doesn’t look clean, so it must be unusable.

False! Looks can be deceiving. Although the Chicago River is murky, it has come a long way from the days of foul pollution and dumping.

In fact, the water in the river is clean enough today that fish species and other organisms are increasing dramatically. Since the Clean Water Act of 1972, pollution being dumped from industrial sources and untreated sewage has been drastically reduced.

Yet in spite of cleaner and more abundant fish habitat, challenges remain. The water in the Chicago River still suffers from fertilizer and motor oil washing in from rainwater runoff. Excess algae grow in the river, blocking light while it lives, and using up oxygen in the water when it dies. Some untreated sewage still gets into the river too. Pollution accumulates as it flows downstream to neighboring states, eventually pouring into the Gulf of Mexico.

We all have to work together to become even better at keeping the Chicago River clean, safe, and enjoyable.

Challenges of Cleaning Up the Chicago River

The three EcoMyths postcards from May to July 2009 have talked about the impacts of people and nature on the Chicago River: its fishing habitat, clean water vs. clear water, and downstream impacts. Here we pull this all together to understand the challenges that remain in cleaning up the river.

Fishing Habitat

In the 1970s, before the Clean Water Act was passed, there were only about 10 species of fish in the Chicago River; today there are almost 70. There are more fish due to the improved water quality over this period.

Recreational fishing is now popular and the fish are safe to eat in limited quantities. The Illinois/Indiana Sea Grant recommends removing parts that are high in fat (organs, head, skin) before eating fish, as that is where contaminants are in highest concentrations.

Additionally, in the past couple of years, fish habitat has become even friendlier since the Friends of the Chicago River installed its Fish Hotel, which has helped to overcome the artificial changes in the river that had made it less hospitable for fish: its smooth walls, dams, and changing water levels.

The Fish Hotel is a multi-level structure with aquatic plants that provide habitat in which fish can rest, feed, and reproduce. Fish species now found in the river include: small-mouth and large-mouth bass, orange spotted sunfish, green sunfish, bluntnose minnows, and black buffalo fish. This June, Chicagoans released 400 baby bluegill into the river with the help of Friends.

Clean Water vs. Clear Water

Clean water and clear water are both important, in rivers as well as other bodies of water. But don’t assume clear water is always clean or that murky water is always unhealthy. Often the reverse is true.

A century ago, Northern Illinois streams were shallow, wide, and murky as water flowed naturally across the landscape. In order to create more dry land for development and farming, people dug deep channels over the years to divert the water into neat, narrow streams.

Water in channels flows faster and erodes more, collecting sediment. Channelized water looks murky, but can still be “healthy” because the murkiness is mostly dirt. So murky water can either be healthy, or very unhealthy.

Clear water may appear clean and pristine, but in the Chicago area, clear water may contain unseen contaminants: fertilizer (which causes algae to grow), dissolved pet waste or human waste (which contains dangerous E. coli bacteria), or dissolved pharmaceuticals that have been flushed down the toilet. While Northern Illinois waste treatment centers filter out solid waste in several steps, they do not disinfect the water nor eliminate dissolved drugs or chemicals.

Downstream Impacts

The Chicago River is one of many tributaries to the Illinois River. Most rivers and surface water in Northern Illinois flow into the Illinois River, rather than into Lake Michigan. Any pollution that leaches into this water system flows downstream to the Mississippi River and eventually to the Gulf of Mexico, contributing to the Gulf’s dead zone.

The dead zone is a large area of water that is very low in oxygen and cannot support aquatic life. Too many nutrients from fertilizer flow downstream into the Gulf, causing enormous amounts of algae growth. When the algae dies, it sinks to the bottom and decomposes, consuming the oxygen supply in the water and killing everything that lives there.

The average size of the dead zone over the past five years is 6,000 square miles, slightly larger than the state of Connecticut. The Gulf of Mexico/ Mississippi River Watershed Nutrient Task Force has set a goal to reduce the size of the zone to an average of 2,000 square miles or less by 2015.

According to the U.S. Geological Survey, Illinois is among the largest sources contributing the majority of the nutrients to the dead zone. We need to continue to work hard to reduce Illinois’ impact if the dead zone is to be reduced by two thirds in only five years.

What You Can Do

  • Join Friends of the Chicago River and become active in river preservation.
  • Attend the Annual River Clean Up (“Chicago River Day”) hosted by Friends of the Chicago River annually in May.
  • Avoid or reduce phosphorus fertilizers (banned in Wisconsin).
  • Be careful what you toss in the sink or toilet, ie no pharmaceuticals, as these can contaminate water bodies.
  • Keep sewer lines functioning properly.
  • Clean up after pets, including on streets and sidewalks, so that pet waste does not wash down the storm sewer.
  • Compost food waste wherever possible instead of using the garbage/food disposal.  Food waste can act just like fertilizer for your garden—but can also cause excessive algae growth in waterways.

Leave a Reply


You are commenting using your account. Log Out / Change )

Twitter picture


Facebook photo


Google+ photo


Connecting to %s