CR Runoff Moves from Backwater to Front Burner

The Cedar Rapids Stormwater Commission was not on my radar, I admit.

But it is now. And that's because it's in the middle of a process that could result in new city rules governing urban runoff. Since, apparently, our governor and Legislature aren't terribly interested in watershed management at the state level, I'm hoping Cedar Rapids can send a local message that somebody actually cares about these issues.

It all starts with this five-member commission, which has an empty seat, if you're interested. It meets to discuss possible rules changes on the third Tuesday of every month at the Public Works Building.

“You're going to see changes, that's for sure,” said Stacie Johnson, commission member and Eastern Iowa program manager for the Iowa Stormwater Education Program. “What they'll look like, I don't know.”

Traditional stormwater policies focus on preventing localized flooding in a very heavy rain event. For instance, a couple of weeks ago, the City Council approved zoning for an asphalt plant with more than 340,000 square feet of hard surfaces, roofs, pavement, etc. (A football field is 57,600 square feet.) It meets the city's minimum stormwater requirements, with a detention basin that can hold water from a 100-year, heavy-rain event and release it at a rate equal to what the undeveloped site would yield during a five-year rain event.

Temporary detention and release serve a practical purpose. But they don't change the fact that, no matter how much you hold or reduce the speed at which you release it, a lot more water is going to run from developed property compared to predevelopment. When rain falls on undisturbed land, about 10 percent runs off, according to Iowa State University's Stormwater Management Manual. That rises to 30 percent or more if 30 percent to 50 percent of the land becomes paved or otherwise impermeable.

The quality of that water also isn't addressed. Runoff can pick up a lot of sediments and pollutants on its rapid ride through the system.

Johnson would like to see rules that address both quantity and quality. The city could nudge developers to adopt practices that stop runoff on site. Perhaps homebuilders could leave topsoil in place instead of scraping it off. The city could designate “environmentally sensitive areas,” including land more susceptible to erosion, cliffs, stream banks, etc., and near impaired waterways on the state's long list of damaged or polluted streams, rivers and lakes.

Reducing runoff can help blunt the severity of flooding. It would be fitting for Cedar Rapids to lead and set an example for the state. But there's sure to be pushback against big changes, so if you care about this, get involved.

Comments: (319) 398-8452;todd.dorman@sourcemedia.net