After the Tacoma Rainiers hung up their cleats to signal the end of the season this month, the city brought in earth-moving equipment to prepare to repave a third of Cheney Stadium’s parking lot.
But this pavement is no ordinary surface. Each square foot of the paved surface has dozens of tiny holes that allow water to drain through instead of flowing to the nearest storm drain.
Pedestrians might notice that it looks rougher than traditional asphalt, like a Rice Krispies treat.
The paving work is the second and final phase of the Cheney Stadium Sustainable Stormwater Project, which seeks to prevent polluted storm water from draining to Leach and Flett creeks, and eventually into Chambers Bay.
The city is paving about three acres of the parking lot and will landscape more than two acres with native plants and trees.
This year’s work more than doubles the portion of the nine-acre parking lot covered with pervious pavement. The city installed permeable paving on one acre about five years ago. It did another acre, as well as part of Clay Huntington Way, last year, said project manager Jessica Knickerbocker.
The pavement improvements mean the parking lot is a “zero discharge site,” said Lorna Mauren, assistant division manager for the city’s water surface section. That should save the city from having to build detention ponds and other infrastructure to meet water quality standards.
The Cheney Stadium paving project is considered a demonstration site for low-impact developments, which can help to reduce stormwater flows and reduce pollution. Knickerbocker said the city wanted to show how green infrastructure and low-impact development can be used in a commercial site.
When water flows across traditional asphalt, it can pick up oil, brake dust and other contaminants that come from cars. That runoff can be toxic to plants, fish and other animals that come into contact with urban streams.
The total project cost will be about $1.7 million, with $1 million coming from the state Department of Ecology through a grant.
The city will study how the pavement holds up over time. Knickerbocker said the city is also monitoring whether the paved surfaces maintain their permeability.
Permeable pavement would not work in every area, Mauren said.
“This really relies on the soil’s ability to accept infiltration of stormwater,” she said, adding that areas with steep slopes, high water tables or impermeable soil would not work for such a project.
Workers with Stan Palmer Construction are preparing the Cheney Stadium site this month, Knickerbocker said. The contractor is scheduled to install porous concrete sidewalks and asphalt next month.
Kate Martin: 253-597-8542