Creeks in Revolt
quickly runs off these surfaces and into small streams, either directly or via a stormwater system. They flood, and the stream channel is eroded by torrents of water; the creek deepens and widens to hold all the excess water. That's why a once-tiny creek may now be 50 feet wide with steep, eroding banks that threaten homes, backyards and roads. The problem worsens as continued development directs more and more runoff into the ailing stream.
Homeowners may have to deal with a stream gobbling up their yard, or even worse, the foundation of their home. Municipalities aren't safe either. They have to pay for expensive roads and bridges threatened by these streams.
The ecology of these streams also is damaged. A lack of trees along these creeks means less woody cover (branches, even entire trees) that provides important habitat for aquatic insects and the fish that eat them. Tree roots are important, too, because they hold soil in place, making the streambank more resistant to erosion, and they provide additional fish habitat when hanging in the water.
Water temperatures, to which many species of fish are sensitive, may increase as a result of a lack of shade normally provided by the dense canopy of a wooded corridor. The fact that water often drains into urban streams from nearby parking lots and streets warmed by the summer sun doesn't help, either.
Water quality, essential to aquatic life, may also be harmed. Oil and other chemicals spilled on parking lots, streets and driveways find their way into streams via stormwater systems. Soil from eroding streambanks and construction sites pollutes the stream, as well. Sediment, the number one pollutant by volume in Missouri streams, may result in a loss of fish habitat as it fills once deep pools.
In an effort to control stormwater in developed areas, urban streams are sometimes lined with concrete. Unfortunately, these so-called "improved" channels provide little in the way of habitat for the fish and aquatic insects that once thrived. Stream channels that are straightened or moved to accommodate a bridge or other type of development have a similar lack of habitat diversity; the channel has a uniform depth and velocity not found in an undisturbed stream.
Urban development can ruin the diversity of stream life. Urban streams are dominated by "tolerant" species of fish and insects, such as green sunfish and midge fly larvae. These organisms can survive in an environment with reduced water quality, warmer water temperatures and lack of habitat diversity. Sensitive species, like darters and mayfly larvae, cannot thrive under these conditions.
Urban development requires common sense and good planning. Leaving wooded greenways or buffer zones along streams will help protect them from erosion. At the same time, these greenways can help filter out many chemicals, such as fertilizers, that can harm the stream.
Greenways also provide travel lanes, food, escape cover and nesting sites for wildlife, and trees shade the water, keeping it cool in the summer. As a bonus, greenways are excellent places for nature trails-they are aesthetically pleasing and often increase the property value of adjacent lands.
Ponds and lakes that are included in developments, residential or commercial, can serve to detain water, slowing its journey into nearby streams. Routing runoff from pavement and rooftops into retention or detention ponds (instead of directly into a creek) is an excellent means to hold back water so it can be released at a more natural rate.
At the same time, common wetland plants found in ponds can act as a natural filter to remove many chemicals contained in water draining from surrounding streets, lawns and parking lots. Ponds also can make a development more attractive.
You can help by contacting your local planning and zoning board to request that stream-friendly methods be included in your community. In addition, you may want to get involved with a Stream Team to help clean up and monitor the health of your favorite local stream.
The next time you drive through your neighborhood on a rainy day, take some time to think about all the rainwater and where it is going when it empties into the storm sewer. Watch as the water level in the creek nearest to your home rises dramatically. It will soon become apparent just how much urbanization is affecting your favorite stream.
To find out more about stream teams in your area, write Stream Team Coordinator, Conservation Federation of Missouri, 728 W. Main, Jefferson City 65101-1534.