In Redmond, Wash., the new Overlake Village park-and-ride is getting a 10-ft-wide-by-36-ft-long-by-18-ft-deep StormCapture PV system with 65, 30-in.-tall PerkFilter cartridges for storm water treatment. It also will receive a 12-ft-diameter Downstream Defender for trash and debris capture. As designed, the PerkFilter system has a design flow rate of 1,428 gpm (or 3.2 cfs), while the Downstream Defender has a treatment flow rate of 18 cfs.
Located adjacent to the Overlake Village park-and-ride on 152nd Avenue NE will be a new light rail station with a targeted open date of 2023. The station’s entrance will be along 152nd Avenue NE, just south of SR520. Once completed, the new light rail line will link Overlake Village to Pioneer Square, with the ride taking about 30 minutes. Contemporary in design, the station was devised in ac
cordance with the city of Redmond's 152nd Avenue Corridor Study and Overlake Village Neighborhood Plan.
Working together, general contractors Kiewit Hoffman and Marshbank Construction along with McMillen Jacobs Associates designed the deep underground storm water vault to meet the regulatory requirements of the Washington State Department of Ecology (WADOE). After review, they concluded a segmented precast concrete panel vault system would be easier to install with its reduced overall pick weight and save months of installation time. The precast solution with the PerkFilter cartridges also would allow sediment and other pollutants to be removed in accordance with WADOE requirements.
WADOE issues guidelines for how storm water runoff is treated before being discharged off job sites. As a developed site with impervious surfaces, the park-and-ride facility ensured its storm water runoff would be as clean as from an undeveloped site with its new storm water management system.
Oldcastle Infrastructure of Auburn, Wash., designed, engineered, manufactured and delivered the precast concrete components of the underground detention system. In total, the Auburn plant supplied the StormCapture PV flat-base slabs, wall panels, top slabs and ladders, cast-iron covers, and risers for the underground detention vault. The plant in Stockton, Calif., supplied the PerkFilter cartridges and associated installation hardware.
The precast concrete storm water vault will hold approximately 48,000 gal of rainwater before slowly releasing it into the downstream storm drain system. A parking lot and pedestrian walkway eventually will cover the detention vault, so storm water will be piped into the underground structure.
According to Oldcastle Infrastructure Area Technical Manager Deon Lourens, “these are complicated systems, and it’s great to see what our capabilities are as a company. The benefits of precast include speed, quality and versatility, which saves time and money for onsite contractors.”