Six years ago, Richard McKown decided to build an affordable housing community of half conventional homes and half homes with green infrastructure to see which performed better.
It would have been a radical idea in any place, but it was practically unheard of where McKown worked: Norman, OK, a place with clay soils, extreme weather and so little in the way of green infrastructure that the city officials weren’t even using that term. Everything that was not a traditional curb-and-gutter simply fell into the category of “best management practices.”
Today, Trailwoods, the community he built, stands as a monument to innovation and cooperation. It includes 17 lots that were developed with conventional stormwater management practices, sitting across a stormwater basin from 17 homes designed with porous concrete, rain gardens, rain barrels and downspouts that divert and capture rainwater.
The neighborhood doesn’t just look different, with one side a typical bare suburbia and the other lush with native plants so high they cover some of the mailboxes. It is also an experiment. It is one of the few developments that clearly demonstrates the value of green infrastructure to control stormwater from small lots.
A $500,000 EPA monitoring grant to the University of Oklahoma, located in Norman, has documented impressive water quality results from the green side: a 30 percent reduction in nitrogen, a 32 percent reduction in suspended sediment and a 152 percent reduction in phosphorus compared with the conventional side. All of those eliminated pollutants would otherwise be flowing into Lake Thunderbird, which provides drinking water for Norman and surrounding areas.
“There is a very big difference in runoff,” said Shanon Phillips, water quality division director of the Oklahoma Conservation Commission, which oversees conservation practices in the state. “If we can make it work in entry-level homes in Oklahoma, then I think we can make it work in other places.”
McKown said he got the idea for green development while in Prince George’s County, MD, for a conference on stormwater. But the Chesapeake Bay region has few, if any, side-by-side projects like this one, according to Cecilia Lane, stormwater coordinator of the Chesapeake Stormwater Action Network. More rare, still, she said, is to find a project that scientists are monitoring under a multiyear plan as Oklahoma University is doing at Trailwoods.
“It’s so expensive to do the monitoring, and then to collect the data, and then to show a difference,” Lane said. “We have seen studies that show one specific thing. It’s so challenging because there are so many variables.”
Brandon Holzbauer-Schweitzer, the graduate student who is monitoring and testing the water samples, said he only knows of one other place that is testing stormwater practices side by side: a suburb of Milwaukee, WI. He said that he hopes the Trailwoods results will inspire other communities to attempt a similar plan and get the same reductions.
“We hoped that it would show something like that, but I wouldn’t have expected to have that much phosphorus retained in the system,” he said. “It makes sense, because the plants took up more phosphorus, but it still was kind of impressive that it removed that much.”
Other benefits to the green side of the development, McKown said, include lower energy bills, less need for landscaping and, he hopes, a sense of the greater good. To that end, all of the streets in the green part of Trailwoods are named after characters and terms from Dr. Seuss’ “The Lorax.”
Houses in Trailwoods started at $110,000, and the green ones did not cost more, though they did cost more to build, because, McKown said, he had to learn how to construct rain gardens and rain barrels.
“We have gotten good enough at building rain gardens that don’t blow out,” said McKown, who owns Ideal Homes with his brother. “But we would like to get the cost down.”
The rain gardens McKown built cost $8,000; he would like to build them for $1,000 apiece.
The monitoring was also a challenge. The university worked with the developer and the Oklahoma Conservation Commission to set up the monitoring stations, which consist of a stream gauge checking the nutrient concentration from two holes in a flume. But the project’s beginning coincided with Oklahoma’s drought, and there wasn’t much to measure until last spring. The monitoring project concludes in December.
Still, McKown and the conservation commission members are excited about the results, and hopeful they will be able to secure funding for more monitoring at Trailwoods, as well as replicating the project elsewhere.
Already, the commission has worked to install several wetlands and restore a grass area to a wild meadow with the support of the broader Norman community. They are, noted commission communications officer Robert Hathorne, the same kind of practices that farmers have been using and calling best management practices for decades. They can still be that for stormwater, whether managers call them that, or green infrastructure or something else entirely.
“These practices that we achieve success with on the landscape level we are now applying to a landscaping level,” Hathorne said. “These stormwater areas, they are just streams in an urban area.”