Stromwater Improvements help at Oregon zoo

Bureau of Environmental Services project uses a sustainable strategy to manage stromwater runoff

PORTLAND, Ore. -- The city-owned parking lot, which serves the Oregon Zoo, the World Forestry Center and the Portland Children's Museum, is returning to a more natural state. Spaces between rows are being widened, but no individual parking spots are being eliminated. Pavement and curbing between rows of parking are being removed and replaced with a drainage layer and native plants and trees. General contractor for the project is CDM, Portland.

The planted areas will also function as stormwater planters that store water and slowly release it back into the sewer system. Stormwater runoff that isn't properly managed flows over streets and other hard surfaces and washes dirt, chemicals and other pollutants into rivers and streams. The landscaped parking lot planters will collect and slow runoff as native plants and soil filter pollutants.

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The parking lot planter will also reduce the amount of stormwater that flows into the combined sewer system that serves the area. The project is the result of a stormwater retrofit and reuse analysis by Environmental Services and local landscape design firm GreenWorks. Based on this analysis, the city and the zoo developed and prioritized a list of desired innovative improvements that would educate the public about alternative stormwater use and treatment.

The city secured $200,000 in funding from the EPA, and is coordinating a Portland Parks & Recreation effort to provide native plantings. At least half of the EPA funding will be spent on improvements to the parking lot itself.

The remainder will be used for projects aimed at capturing additional stormwater runoff on zoo grounds, including a proposed wetland planter water feature to filter water and minimize runoff down pathways.