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Urban conservation a growing concept

By Staff | Oct 28, 2008

Traditionally, eastern city dwellers may think of urban areas as just vast areas of concrete, devoid of the vegetation so characteristic of many Midwestern cities.

If Wayne Petersen had his way, that would all change.

Petersen, of the Iowa Department of Agriculture & Land Stewardship, talked about urban conservation at the Ag for Reporters seminar last Thursday in Ames.

In his remarks, Petersen highlighted projects he has worked on in the Iowa Lakes region that have strived to reduce runoff into area lakes. Strategies have included permeable concrete and islands of vegetation in parking lots that have made use of runoff rather than let it merely enter storm sewers.

Regionwide, though, new and innovative methods of reducing runoff have a long way to go to restore ecosystems to their original state.

If you go back far enough, Petersen said historically 10 percent of stormwater is runoff while 50 percent goes to groundwater. Now, in urban areas, 55 percent is runoff while 15 percent goes to groundwater.

Solutions Petersen suggested include permeable pavement, soil quality restoration and native landscaping.

Rural areas have greater runoff than a century or so ago as well, said Petersen. A big reason is that when original prairie had 10 percent organic content it could handle a six-inch rainfall. Now that field soils average 2-4 percent organic content, they can handle far less runoff, he said.