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Moving Green Infrastructure Forward at the Port of Seattle

Pilot program will test natural ways to cleanse stormwater
April 21, 2014

The Port of Seattle kicks off a pilot project today to reduce the amount of polluted runoff reaching Puget Sound. The Port is hosting a two-year study site for two unique metal boxes which will bloom into rain gardens and help reduce pollutants. This effort is in partnership with King Conservation District, Sustainable Seattle, Gealogica LLC, and Splash Boxx LLC.

“The Port of Seattle is working with many partners to restore Puget Sound.” said Commissioner Bill Bryant. “There is no single solution to saving Puget Sound, no silver bullet, but there are hundreds of different things we can do and this is one of them.”

Moving Green Infrastructure (MGIF) is a research/demonstration project to test the water quality performance of two innovative stormwater treatment techniques, a large “rain garden in a box” and a special soil mix with local, volcanic sands. Water quality from a roof in an industrial port area will be tested before and after going through the boxes to see how these two techniques perform.

This research/demonstration project is part of growing efforts to reduce the amount of polluted runoff reaching Puget Sound, which is estimated to receive between 14 and 94 million pounds of toxic pollutants every year. Two large steel boxes, called Splash Boxxes, are being installed at Terminal 91. These boxes are a blend of rain garden and cistern, two practices referred to as low impact development, or LID.

“LID works,” said Amy Waterman of Gealogica, “resulting in 98-99% reduction in runoff volume and 83-99% reduction in key pollutants.”

The information from this study will help shed light on the potential for these bioretention planter boxes to improve water quality of polluted runoff in commercial/industrial areas and whether soil mixes used in rain gardens and bioswales could be improved. One box is going to have a unique soil mix with volcanic sands and the other will be a typical rain garden soil mix.

“We developed Splash Boxx for just this type of industrial application,” said David Hymel of Splash Boxx LLC. “We are very pleased to be able to provide the delivery system that tests an exciting new bio retention soil mix design.”

“King Conservation District in partnership with Seattle Public Utilities supported this project with a grant for $49,700 because we think it is important to explore innovative solutions for our stormwater issues,” said Sara Hemphill, Executive Director, King Conservation District.

The water going into each box from the roof runoff will be tested once a month during the rainy seasons for phosphorus, nitrogen, bacteria, zinc, and copper. Splash Boxxes are part of an innovative stormwater research and demonstration project funded by King Conservation District and managed by Sustainable Seattle through a contract with Gealogica LLC. The Port of Seattle is providing the site for two years.

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