Urban areas are dominated by hard surfaces such as streets, roofs, and parking lots. These surfaces allow very little rain and snow to penetrate into the ground underneath, and are therefore called impervious surfaces. Whereas natural land cover absorbs about 90% of precipitation, suburban neighborhoods may only soak up about 70% and downtowns are even worse at 45%. What is not absorbed by the ground flows downhill and becomes stormwater runoff.
Unfortunately, stormwater runoff is not only a nuisance but it can also be unsafe. When there is too much unabsorbed water, our buildings and streets flood to the detriment of our safety and pocketbooks. As water moves downhill, it picks up pollution that is in our streets and yards. Common stormwater pollutants include soil, oil and grease, pesticides, animal feces, and trash.
Have you ever wondered what happens to stormwater that disappears down a street drain? In some communities, the drain goes to a sewage treatment plant where pollutants are removed. However, in many of Illinois’ communities, the street drain goes directly to nearby streams and lakes without any filtration of the water. Subsequently, our waterways become filled with pollution and lose their economic and ecological value.
The Illinois Environmental Protection Agency considers urban stormwater runoff to be the 4th leading cause of water impairment in the state.
Fortunately, there are a number of ways that residents, businesses, and municipalities can protect our rivers and lakes by reducing stormwater pollution. For starters, we need to keep trash, leaves, and other debris out of our streets and stormwater drains. Construction sites should be closely monitored to ensure that bare soil stays on site. We can also make a difference by incorporating water-loving green infrastructure such as rain gardens, rain barrels, porous pavement, wetlands, and parking lot infiltration islands.
Prairie Rivers Network is working with citizens, developers, and local governments to reduce urban stormwater pollution. Our projects include the publication of a Rain Garden Brochure, presentations on how to install rain gardens and monitor construction site runoff, and technical assistance for green development.
The US Environmental Protection Agency recommends the following ten things you can do to prevent stormwater runoff pollution:
- Use fertilizers sparingly and sweep up driveways, sidewalks, and roads
- Never dump anything down storm drains
- Vegetate bare spots in your yard
- Compost your yard waste
- Avoid using pesticides
- Direct downspouts away from paved surfaces
- Take your car to the car wash instead of washing it in the driveway
- Check your car for leaks, and recycle motor oil
- Pick up after your pet
- Have your septic tank pumped and system inspected regularly
