The bricks in parking spaces at Downtown Boise's Whole Foods-Walgreens complex aren't there just for looks.
Between and under the bricks, known as pavers, lie layers of rock from about 3/8 inch to 2 inches in diameter. The gravel filters out solid particles, nutrients and other pollutants from rainwater that washes over it. After leaching through the rocks, the cleaned water enters the native soil below and may ultimately descend into the groundwater.
So far, the Whole Foods complex is the Treasure Valley's only major commercial project to incorporate permeable paving.
The reason is money.
Permeable paving costs more than a completely asphalt parking lot that pipes storm water to a retention pond. Rick Duggan, a partner in Schlosser Development, the Texas company that completed the Whole Foods-Walgreens complex last fall, places the extra cost of permeable paving in "the low six figures."
That premium made sense for the nearly $5 million project, Duggan says. Environmental concerns nixed Schlosser's original plan to pipe storm water under Myrtle Street and into Julia Davis Park.
In that situation and others like it, Duggan says, permeable paving is a good option. But if cheaper alternatives are possible, developers need motivation besides money to turn to permeable paving.
"You have to be, I would suggest, altruistic, headed for a LEED platinum certification or some other community benevolent approach to the world," he says. "There's no question it's a premium."
LEED stands for Leadership in Energy and Environmental Design. It is a voluntary program coordinated by the U.S. Green Building Council that ranks the environmental friendliness of a building on a range of levels.
In the long run, permeable paving can save money, says Mark Dooley, architectural sales representative for Basalite Concrete Products in Meridian, which supplied the paving for the Whole Foods-Walgreens parking spaces. The bricks and most of the gravel under them last longer and require less maintenance than asphalt paving, Dooley says.
Asphalt needs a new seal coat every few years and should be replaced at least every couple of decades. Dooley says permeable paving is built to last 50 years and needs a cleaning no more than once a year.
Another saving is space. Instead of devoting acreage to retention ponds, projects with permeable paving can use that space for more building or more parking.
But those savings aren't realized right away - a problem for any developer, especially ones who sell their projects as soon as possible, Dooley says.
Homes and government projects, such as Boise's WaterShed and Hyatt Hidden Lakes Reserve, have been the core permeable paving clientele, Dooley says.
The Boise WaterShed is an educational center near the West Boise Wastewater Treatment Plant on Joplin Road. The Hyatt Hidden Lakes Reserve is the site of a stormwater treatment project near Maple Grove and McMillan roads. It features 28 acres of wetlands and wildlife habitat surrounded by undeveloped land.
Basalite Concrete sees permeable paving as a big growth market in the industry.
"Business owners, they're still about the dollar," Dooley says.
Sven Berg: 377-6275