Background:

Floodplain Management and Regulation.

Title 86 of the Revised Code of Washington, entitled "Flood Control," contains a series of chapters pertaining to the management and regulation of floodplains. Statewide, the Department of Ecology (DOE) is authorized to oversee the management of floodplains in conjunction with counties and flood control zone and flood control districts. With respect to floodplain management, the duties of the DOE include:

the review of county, city, or town, floodplain management ordinances;
generally providing technical guidance and assistance to local governments; and
assisting local governments in identifying the location of the "one hundred year floodplain."

Flood control zone districts are authorized to create zones within a county for the purpose of developing or operating flood control projects or storm water control projects.

Flood control districts may be organized in a city, or in any part of a county, or among counties, for purposes that include the planning, development, acquisition, management, or maintenance of any facilities necessary to control floods, lessen their dangers, and reduce damages.

Growth Management Act.

The Growth Management Act (GMA or Act) is the comprehensive land use planning framework for county and city governments in Washington. Enacted in 1990 and 1991, the GMA establishes numerous requirements for local governments obligated by mandate or choice to fully plan under the Act (planning jurisdictions) and a reduced number of directives for all other counties and cities.The GMA requires all jurisdictions to satisfy specific designation and protection mandates. All local governments, for example, must designate and protect critical areas. Critical areas are defined by statute to include wetlands, aquifer recharge areas, fish and wildlife habitat conservation areas, frequently flooded areas, and geologically hazardous areas.The GMA includes planning requirements relating to the use or development of land in urban and rural areas. Among other obligations, counties that comply with the major requirements of the GMA (planning counties) must designate urban growth areas (UGAs) or areas within which urban growth must be encouraged and outside of which growth can occur only if it is not urban in nature. "Urban growth" is defined by the GMA, in part, as a reference to growth that makes intensive use of land for the location of buildings, structures, and impermeable surfaces to such a degree as to be incompatible with the primary use of land for specified agricultural, mineral resource, and rural purposes.The GMA includes many requirements pertaining to UGAs that planning jurisdictions must satisfy. Using population projections made by the Office of Financial Management, planning counties and each city within these counties must include within UGAs areas and densities sufficient to permit the urban growth that is projected to occur in the county or city for the succeeding 20-year period. The UGAs must permit urban densities and include greenbelts and open space areas. The UGA determinations may include a reasonable land market supply factor and must permit a range of urban densities and uses. Additionally, a UGA provision grants planning jurisdictions comprehensive plan discretion to make many choices about accommodating growth.

Summary of Bill:

Subject to specified exceptions, a county, city, or town is prohibited from expanding an UGA into the one hundred year floodplain of any river or river segment that:

is located west of the crest of the Cascade Mountains; and
has a mean annual flow of 1,000 or more cubic feet per second.

This prohibition does not apply to UGAs:

that are fully contained within a floodplain and lack adjacent buildable areas outside the floodplain; or
where expansions are precluded outside the floodplains because: (1) urban governmental services cannot be physically provided to serve areas outside the floodplain; (2) the urban growth area or expansion would be too irregular to effectively serve with urban governmental services; or (3) expansions outside the floodplain would require a river or estuary crossing to access the expansion.