South Central Action Area
The South Central Action Area is home to 2.5 million residents living in three of Washington’s largest cities—Seattle, Bellevue, and Tacoma, and in suburban and rural residential development that reaches across unincorporated King and Pierce Counties. The northernmost portion of the action area is located in southwest Snohomish County.
South Central Puget Sound is the most urbanized portion of Puget Sound and includes commercial and residential buildings, large areas of pavement, a heavily modified shoreline, and an extensive road network. Although portions of the action area have been intensively developed, approximately 77 percent of the area is not considered urban, with vast tracts of agricultural lands in rural King and Pierce Counties, and undeveloped wilderness in Mount Rainier National Park and the Mount Baker-Snoqualmie National Forest.
Three major river systems originate in the Cascades near Snoqualmie Pass, Cascade Pass, and Mount Rainier, travel through forests and farms, and empty into Lake Washington and Puget Sound. Glacial melt from Mount Rainier feeds the Puyallup/White River system, while the Green/Duwamish and Cedar/Sammamish are supplied by snow melt and rainfall. Lowland areas receive average rainfall of 40 inches per year. In highly urbanized portions of the region, many streams or stream segments have been placed in drainage pipes and re-assert their presence during storms and flood events.
The two largest bays in the South Central area are Seattle’s Elliott Bay and Commencement Bay, which is near Tacoma. Vashon-Maury is the largest island south of the Admiralty Inlet. The major currents within the saltwater basin of central Puget Sound generally flow northward along the west side of Vashon Island, and southward through the East Passage. The marine waters of Puget Sound form warm layers at the surface during the summer months due to river input and solar heating. These layers are mixed during winter months by seasonal winds and cool weather. An underwater sill by the Tacoma Narrows also alters the pattern of marine water circulation.
South Central Puget Sound is the economic driver of the region, and largely of the State of Washington. The region generates over $200 billion in annual economic activity, comprising approximately 62 percent of the gross state product. Major commercial and industrial enterprises are concentrated here, including technology, aerospace, finance, insurance, health care, business and professional services, commercial fishing, recreation, and tourism. These industries are served by international port facilities in Seattle and Tacoma, along with SeaTac international airport, Boeing Field, and passenger and freight railroad services. The region has 14,900 acres of designated manufacturing industrial centers in six locations: Ballard Interbay, Duwamish, North Tukwila, Auburn/Kent, Overlake, and the Port of Tacoma. Water supply for most of the population of the area is provided by the City of Seattle and the City of Tacoma, through their operations on the Cedar and Green Rivers, respectively.
Following the adoption of the Growth Management Act in the 1990s, land use strategies have been somewhat effective in containing sprawl, as more than 93 percent of the growth in King County since 1996 has been concentrated within the designated urban growth boundary. Significant tracts of commercial forest and agriculture remain in the eastern and southeastern portions of the area. There are many challenges in trying to retain habitat features and natural amenities while trying to accommodate several hundred thousand new residents to this area in the next 20 to 25 years.
In general, the residents of the South Central Action Area are remarkably informed and engaged citizens. There is a high level of volunteerism and civic engagement with many agencies and local NGOs benefiting from the resources and knowledge base of the public for assistance with on-the-ground projects and public process for furthering recovery.
The varied ports and waterways of South Central Puget Sound have made it an international shipping center for regional and national industries, natural resource extraction (logging, fisheries, mining), and agricultural products. Urban estuaries support many small marine, ship building/repair, and industrial enterprises. Public transportation to Kitsap County and Vashon Island is provided by the Washington State Ferry System and other vessel traffic consists of passenger ferries, fishing boats, research vessels, small recreational craft, and cruise ships. Recreation spots include Lakes Washington, Sammamish, and Tapps; Puget Sound beaches such as Alki Beach in West Seattle, Seahurst in Burien, and Pt. Defiance in Tacoma; and along the Mountain to Sound Greenway along Interstate 90, the middle Green River, and the White River above Enumclaw. The headwaters of the major rivers in this area are protected through their status as parklands managed by the National Park Service, wilderness areas managed by the United States Department of Agriculture (USDA) Forest Service, and the headwater source areas of the water supplies of Seattle and Tacoma.
The federal listing of Puget Sound Chinook was the first time a threatened species listing for salmon had occurred in such an urban environment. Despite the extensive urbanization of South Central Puget Sound, Chinook salmon and other salmon species spawn in the major rivers and lakes. Unique salmon populations include the spring run of White River Chinook, Issaquah Creek and Cedar River summer and fall Chinook, Lake Sammamish Kokanee, and Lake Washington Sockeye. The Green River is one of the top ten Steelhead rivers in Washington and supports substantial natural and hatchery populations of salmon. Bull trout, Rainbow and Coastal Cutthroat trout, and Coho, Chum, and Pink salmon are also present in some of the river systems. Strong community efforts and watershed partnerships, some through formal inter-local agreements, are focused on strategic, science-based salmon recovery efforts throughout the area, and habitat restoration programs depend on a combination of local, regional, state, and federal funding. While other fish, wildlife, and bird communities are abundant in undeveloped portions of the action area, those species that coexist well with humans are generally present in the urban sectors.
Source: this Profile is listed in the The Action Agenda in South Central Puget Sound (PDF), pages 411-425 of the 2012/2013 Action Agenda for Puget Sound, August 2012