The Growth Management Act requires that jurisdictions planning under its authority develop and adopt a process for identifying and siting essential public facilities, including those facilities typically difficult to site.
The State Office of Financial Management maintains a list of those essential State facilities that are required or likely to be built within the next six years. The list includes: airports; state education facilities; state or regional transportation facilities; state and local correctional facilities; solid waste handling facilities; in-patient facilities including substance abuse facilities, mental health facilities and group homes; waste water treatment facilities; utility and energy facilities; and parks and recreation facilities.
King County Policies also identify the parameters for the siting of new public capital facilities of a county- or state-wide nature. The facilities shall be sited so as to support countywide land use patterns, support economic activities, mitigate environmental impacts, provide amenities or incentives, and minimize public costs. Public facilities development projects are also to be prioritized, coordinated, planned and sited through an inter jurisdictional process.
Interstate 90 represents the community’s largest essential public facility of a regional or statewide nature. Given the lack of available land, the residential nature of Mercer Island and the comparatively high land and development costs, future siting of major regional or state facilities on Mercer Island is most likely unrealistic and incompatible with existing land uses.