Green River Flood Control Zone District
King County, Washington
The Green River Flood Control Zone District was established to maintain and operate important flood protection facilities on the lower Green River. The District's boundaries encompassed the lower Green River drainage basin from Auburn to Tukwila covering approximately 68 square miles. It was unique from other flood districts in the county as it was a quasi-municipal corporation with taxing authority and a budget.
At the end of 2007, the Green River Flood Control Zone District was sunsetted and replaced by the King County Flood Control Zone District (KCFCZD). The new countywide district has similar goals and objectives to the Green River Flood Control Zone District, working to maintain and repair levees and revetments and acquire at-risk floodplain properties. Additionally, the new KCFCZD will work to improve countywide flood warning and prediction capacity. The KCFCZD adopted the 2006 King County Flood Hazard Management Plan as its initial mandate.
Goals and objectives
The goals and objectives of the Green River Flood Control District were to operate, maintain and repair important river flood protection facilities and pump stations within the lower Green River watershed in order to maximize public health and safety and to coordinate flood hazard reduction planning, programs and projects between King County and the Cities of Auburn, Kent, Renton and Tukwila. This included developing and implementing contemporary standards and procedures consistent with the Endangered Species Act and other natural resource protection regulations.
The District was in existence for over 40 years when, in 1960, the District was initially established with concurrence of the lower Green River Valley cities of Auburn, Kent, Renton and Tukwila. Early activities were limited to local sponsorship of federal flood control improvements affecting tributaries to the Green River, such as construction of the pump stations serving the Springbrook Creek and Southcenter drainage, and some limited property acquisitions affecting Mill Creek channels in Auburn.
In 1990, the King County Council passed a Resolution which activated the District's taxing authority and established the first budget and tax levy for the District. Subsequently in 1992, the interlocal agreement between King County and the cities of Auburn, Kent, Renton and Tukwila was renewed for a ten-year duration for the purpose of continuing the principles embodied in the Green River Basin Program interlocal agreement; administration of the District's budget and work program; and setting forth the standards and procedures for maintaining and repairing the levees, revetments and pump stations located within the District's boundaries.
Responsibilities and accomplishments
The District was responsible for maintaining 98 flood control facilities on the Green River lying between the Cities of Auburn and Tukwila. Since 1991, 36 major maintenance, repair and habitat enhancement projects were completed using a combination of federal, state, local and grant funds. The total cost of these 36 projects was $7,960,550.
In addition to maintaining the flood control facilities, the District operated two pump stations, the Black River and Tukwila Pump Stations, constructed by U.S. Soil Conservation Service in the 1970s. A third, the Segale Pump Station, was constructed by the District in 1997. The Black River Pump Station regulates flow of water from the Black River drainage basin into the Green River and serves to block high flows from the Green from flooding up into the Black River & Springbrook Creek, and the Earlington Industrial Park in Renton. The Tukwila Pump Station, located adjacent to the Green River, pumps stormwater from the Southcenter commercial area into the Green River. The Segale Pump Station controls groundwater saturation previously affecting the stability of the Segale Levee foundation soils.
Annual routine maintenance activities were also performed by the District. These included access gate repairs and replacements; project site and in-water monitoring; removal of invasive plant species from newly re-vegetated flood protection facilities; installation of native riparian trees and shrubs; sign installation; and routine facility flood damage assessments. District personnel also participated in the patrol and inspection of its flood control facilities during flooding events and coordinated flood warning and emergency response activities between King County, the lower Green River valley cities, and the U.S. Army Corps of Engineers.
What are the risks and potential damages that could occur in the Green River Basin as a result of flooding?
A preliminary risk-based analysis study was completed. The study examined the potential damages that could occur as a result of levee and revetment instability. The objective of the study was to develop a preliminary estimate of the expected annual damage to structures and structure contents within the district's floodplain.
Preliminary Risk-Based Flood Damage Analysis (Adobe Acrobat 1.0 mb)
Annual reports were published that provide a detailed account of the program activities.
For questions about the Green River Flood Control Zone District, please contact Steve Bleifuhs, River and Floodplain Management Section.