The Gateway Regional Stormwater Facility (GRSF) provides flow control and enhanced treatment which will support the development of approximately 31 acres in the commercial area of the City of Blaine’s Gateway Properties. This area is comprised of mainly the defunct municipal airport, with most of the lots having been sold to private developers. Stormwater treatment is provided via a stormwater constructed wetland. A dam safety permit was required. According to the Western Washington Hydrology Model, over 14 acre-ft of water would be detained to satisfy the 100-year flow control requirements. The GRSF is designed to handle the 500-year storm to satisfy the Department of Ecology’s dam safety office. The GRSF design includes a 15-ft wide access road for facility maintenance, as well as a 12-ft wide walking trail that circumnavigates the facility.