Plentiful rainfall in Portland, Oregon is more than a nuisance for residents and a deterrent for visitors. It's also a public-works nightmare. The city's under-sized storm sewer system is frequently overwhelmed, causing combined rainwater and sewage to be dumped into the Willamette River, creating a serious biohazard, even after only moderate rainfall.
A playful and effective local-scale solution to managing excess runoff has appeared at the recently completed New Seasons Market, which seeks to reverse the traditional practice by keeping rainwater on site in two ways.
Downspouts from the main roof deliver rainwater to a rooftop garden over the entry vestibule. Here, water artfully cascades along a steel sculpture of migrating salmon to the waiting plants. A second strategy collects parking-lot runoff in several holding areas. As these holding areas reach capacity, water is pumped into planted swales distributed around the site. Carefully selected vegetation in all these areas helps by absorbing and filtering runoff.
Since 1997, Portland has been awaiting completion of a city-scale stormwater diversion project. But it has suffered staggering cost overruns, and its long-term effectiveness seems increasingly dubious. The "Combined Sewer Overflow Project" (commonly called the Big Pipe), seeks to correct flaws in the 1950s-era sewer system by 2011. The plan is to divert runoff through a new network of huge storm sewer pipes running roughly parallel to the river. But recent analysis has questioned the long-term efficacy of this solution in light of continued conventional development in Portland.
The New Seasons Market exemplifies a handful of simple strategies that can be effectively applied in both new and existing buildings. These small-scale techniques, when multiplied across all new construction, as now called for, could take pressure off the city's stressed infrastructure and ultimately contribute to healthier rivers and streams.
Yours from Portland,