Marysville, Washington United States
City of Marysville
$1,000,001 - $2,500,000
The city of Marysville, WA needed to make street improvements and build a park-and-ride facility in an area that sat adjacent to a a freeway corridor and had a lack of storm water conveyance facilities. They partnered with the Washington State Department of Transportation and Community Transit to build a new $1.5 million, 202-stall park-and-ride. Using permeable pavers instead of traditional asphalt allowed stormwater to pass through and soak into the ground. The project also allowed for more parking spaces to be built because a stormwater pond was no longer needed.
Triple Bottom Line
Economic: By creating a stormwater solution on site, the city saved an estimated $1.2 million that it would have cost to build a conveyance system to carry the excess water away from the site for discharge to the Snohomish River.
Environmental: The site had inherently sandy soils that provided a good opportunity for infiltration of the project's storm water runoff. An infiltration pond for the site was not practical because of the limited area available, the high water table, and the difficulty in conveying storm water around the flat site. The design team suggested the use of a system that would emulate natural patterns by allowing infiltration to occur throughout the site also made traditional solutions problematic. This concept was implemented by using the paver block system. The innovative process consisted of adding natural organic material to well-draining native sand (prevalent at the site) to achieve biological treatment of the storm water runoff in order to capture pollutants. Soil samples were taken and tested for structural strength appropriate for supporting road surfaces, appropriate infiltration rates, and a minimum cation exchange capacity (necessary for capturing pollutants found in storm water). Through this process, they were able to determine that organically mixed sandy soil can have enough organic material to achieve the necessary treatment characteristics, while still keeping the sandy soil fairly "clean" for it to serve as a good structural foundation for the parking lot brick pavers.
Social: The project has become a community asset, turning an under-used stretch of property near I-5 into a visually appealing and functional treasure for the citizens of Marysville. The drainage feature was severly tested almost as soon as the park-and-ride lot was dedicated. A major storm on October 20, 2003 dropped 1.6 inches of rain in a 24-hour period. The lot drained beyond expectations and no significant standing water was present.
Crystal Donner, President/CEO
Pereet Engineering, Inc.