St. Louis Runoff Concerns Biologists

The storm water that runs off all the driveways, streets and parking lots in new suburbs in the St. Louis area is killing off neighborhood streams and the things that live in them, several biologists say.

For example, Kevin Meneau, a biologist with the Missouri Department of Conservation, said two of the 17 streams he’s studied in St. Louis and Jefferson counties had more than 40 species in them. The other streams, all near suburban developments, had between four and 14 fish species.

"The No. 1" environmental "impact I’ve seen is not taking care of our storm water," Meneau said.

Runoff from subdivisions and shopping centers scours banks, cuts channels and changes the flow of streams, according to studies presented in San Francisco last week at the American Geophysical Union conference.

Some suburbs, such as O’Fallon, which has tripled its population since 1990, are using detention ponds and filtered storm sewers to try to slow the storm water.

Undeveloped land acts like a sponge and slowly drinks the water that falls on it, U.S. Geological Survey biologist Tom Cuffney said.

But pavement "is like putting Saran wrap over the sponge," he said. "Everything runs off."

After water runs off the pavement into storm drains, it heads into neighborhood streams, along with trash, dirt, chemicals and pesticides.

The fast-rushing water also changes a stream’s shape, meaning that the streams become more prone to flash floods and that all the water that should seep into the streams from the soil doesn’t. That means, on average, creeks are drier, which leads to less watery habitat.

The excess force of the runoff also means a stream scours its banks and cuts a deeper channel. The narrower channel leaves less room for fish, insects and algae.

The flashy floodwaters carry sediment that fills in stream hollows and buries rocks in the channel bed, another loss of great habitat, Cuffney said. Only the biggest floods will clear out the sand and sediment.

"You’ve got a problem that’s going to last a long time," Cuffney said. "It’s kind of like living in a house and someone coming up with a dump truck. Dirt starts to come in the window, and you’re going to have a hard time living in there."

The Missouri Department of Natural Resources has asked developers to change their construction practices if storm water from a development could affect a stream on a list of polluted streams the department keeps.

But home builders say the state is acting before identifying specific sources, amounts and types of pollution. In January, the Home Builders Association of Greater St. Louis sued DNR, saying sediment occurs naturally and is not a pollutant or a nuisance.

Steve Jeffery, an attorney for the home builders association, said the group wants the state to do its research before regulating runoff.

The association doesn’t discount the environmental impact of development. But its executive vice president, Pat Sullivan, said people should have the choice to live where and how they want. He said housing developments mean "healthy economic growth, job creation and quality neighborhoods in a suburban environment."

Still, storm sewer systems have to keep up with the development. Jeff Theerman, director of the Metropolitan St. Louis Sewer District, said he has a billion dollars in storm water needs. Next year, the sewer district, which covers the city and most of St. Louis County, plans to submit a proposal to its rate commission to charge customers based on the size of the property. Currently, all customers pay the same monthly charge of 24 cents for storm water.

Source: EPA