A Stormwater Park in downtown Seattle, the Swale on Yale Project treats 190 million gallons of stormwater annually within the streetscape while also providing a gathering place and backdrop for life in a revitalized neighborhood in downtown Seattle. From 2015 to 2016 Herrera and Seattle Public Utilities (SPU) implemented an intensive water quality and quantity monitoring effort to assess the performance of one block of the four block swale project. The monitoring entailed continuous flow measurement of influent stormwater and treated effluent from the underdrain outlet and the surface flow outlet. Automated samplers were used to collect water samples from these same monitoring locations. The project was able to remove suspended solids for $20 – 28 per pound, compared with a more typical $60 – 64 per pound. The performance was better than the majority of the BMPs employed by SPU, including bioretention. Despite this, the nutrient removal performance was insufficient, and in the case of ortho-phosphate, the system exported.
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Swale on Yale: Innovative Regional Green Stormwater Infrastructure in an Urban Neighborhood
Reference: Herrera and SPU. 2017. Swale on Yale: Innovative Regional Green Stormwater Infrastructure in an Urban Neighborhood. Presented at StormCon, Bellevue, Washington, August 27 – 31, 2017.