The High Point neighborhood in Seattle, Washington — a mixed-use, mixed-income community that is seven miles from the space needle — has been winning national awards since its redevelopment began in 2003. At the end of 2007, it achieved worldwide recognition, receiving the Urban Land Institute’s 2007 Global Award for Excellence.
Before its redevelopment, the 120-acre site was occupied by barracks-style housing that had been built to accommodate wartime workers at Boeing. Then the Seattle Housing Authority, a public corporation that provides affordable housing to over 25,500 people, initiated a renewal effort that resulted in the largest sustainable mixed-use urban neighborhood in the U.S.
One of High Point’s most prominent sustainability features is its stormwater management system, which represents the largest urban natural drainage system in the country and is part of the Seattle Public Utilities’ Natural Drainage System (NDS) program. The project is cutting-edge in its use of porous concrete, having the first porous-paved roadway in the state. The roadway, along with more than two miles of porous pavement sidewalks, allows rainwater and runoff to filter into the ground. (One of High Point’s numerous awards was a Sustainable Merit Award from the Washington Aggregates & Concrete Association). According to the Seattle Daily Journal of Commerce, 10 percent of the development’s 60 percent pervious area is composed of porous concrete.
Narrow, sloped streets route stormwater to vegetated swales along the curbs, and rainwater management techniques are employed in the neighborhood’s residences as well. Homes use rainwater to nurture rain gardens (landscaped areas which are contoured and planted in a way that enables them to absorb and treat water year-round). Rooftop runoff that cannot be routed to a rain garden is dispersed into the soil using perforated pipes.
The High Point site represents about 10 percent of the watershed for Longfellow Creek, an important ecosystem for salmon. The National Academy of Public Administration estimates that the new drainage system will reduce direct runoff into the creek by 65 percent. By the time water does reach the stream, it will have been naturally cooled and filtered, making the site effectively function as an open meadow.
According to its website, Seattle Public Utilities began monitoring the first phase of the drainage system in January 2007, and data on its performance will be available after 3 years. Phase II construction at High Point, which involves the construction of more roadways as well as the construction of rental housing, is currently underway. The entire redevelopment project is expected to be complete by 2010.
Image Credit: Seattle Housing Authority