Client: Costco Wholesale, Issaquah, WA
Costco's development of a new store in south Snohomish County, just north of Woodinville, required innovative strategies and analysis to protect adjacent Little Bear Creek.
The Costco underground stormwater storage facilities reduce peak flows in Little Bear Creek.
The Costco store site is located on 14.38 acres between SR 522 and Highway 9. An additional 2.35 acres of Highway 9 improvements were planned along the store's frontage.
Drainage from the site crosses SR 522 in WSDOT culverts and enters Little Bear Creek.
The WSDOT permit required the Costco stormwater system to meet Department of Ecology flow control standards.