With outstanding green infrastructure and transit access, this Seattle development could be a model for towns everywhere
Leave it to a city famous for coffee and rain to produce possibly the best example of transit-oriented urbanism, natural public space, and green stormwater infrastructure I have ever seen. This Seattle redevelopment is green in so many ways that it is hard to know where to start.
Maybe we should start with the parking lot, because that's what the whole nine-acre site was before redevelopment began. Ugly. Horrible for the environment. A complete waste of urban space.
The site is in an area that is transitioning from automobile-oriented and suburban in feel to walkable and lively. It sits just south of the Northgate shopping mall, northeast of a community college, a couple of blocks east of the I-5 freeway, and just west of an area of single-family homes. It is transit-rich, however, just a block from a major bus transfer station (with planned light rail access). With better amenities and some investment, the potential for smart, green redevelopment is immense.
Enter the city of Seattle, with a sophisticated initiative to bring long-buried Thornton Creek back to life above the surface, where it belongs. Add lots of carefully planned nature (not really an oxymoron when we're dealing with a city), arranged to be highly walkable and educational as well as environmentally beneficial. The creek restoration was led under contract to the city by Seattle's SvR Design, which previously designed the landscape and green infrastructure features of the much-celebrated, mixed-income High Point development, also in Seattle.
Here's how the Landscape Architecture Foundation puts it:
Carved out of an abandoned parking lot, the Thornton Creek Water Quality Channel treats urban stormwater runoff from 680 acres within a necklace of channels, pools, and terraces designed to mimic the performance of a natural creek. Its lush plantings, overlooks, and paths have added 2.7 acres of public open space to the Northgate Urban Center and catalyzed surrounding redevelopment. The facility is a model for how multi-functional landscapes can be integrated into the dense urban fabric.
The redevelopment not only added 530 units of housing
(net density: 96 units per acre) and 50,000 square feet of retail space;
it simultaneously accomplished the following, according to the LAF:
- Increased open space within the Northgate Urban Center by about 50 percent.
- Provided pedestrian links from adjacent commercial and residential neighborhoods, shortening walking distances by 50 percent.
- Reduced impervious surfaces by 78 percent.
- Designed to remove an estimated 40 to 80 percent of total suspended solids from 91 percent of the average volume of annual stormwater runoff from the 680-acre drainage basin.
- Created new habitat within this heavily paved commercial area.
Within one month after opening, native birds were observed at the
project. A variety of desirable native volunteer plants have migrated
into the site and begun to establish.
85 percent of the project's plant palette are native species, including 172 native trees, 1,792 native shrubs, and 49,000 native perennials, herbs, grasses, rushes, and sedges. The planting mix and the channel's alignment will be allowed to evolve naturally over time. When was the last time you saw this much additional urban density, increased natural space, and reduced imperviousness on the same site? (For more of the technical details, see the city's extensive report on the project.)
The [Thornton Creek Water Channel] Facility is designed to remove pollutants from stormwater by slowing urban runoff before these flows enter the creek. The Facility, in conjunction with improvements to surrounding roadways, Northgate Mall, Northgate Library and the Northgate Community Center, is part of a larger strategy to revitalize the Northgate Urban Center. Community involvement was instrumental in making the Facility successful from a number of perspectives. A stakeholder group, made up of a broad balance of community, environmental and business interests, helped drive the Facility's design, which resulted in a Facility design that integrates environmental and commercial concern . . . The Facility was constructed by Seattle Public Utilities with funding support from Washington State Department of Ecology via a Washington State Water Pollution Control Revolving Fund Loan.