Flood-Related News

News from local media about Green River flooding risks...

Local history

Josephine Emmons Vine - Auburn: a look down Main Street

Florence K. Lentz - Kent-Valley of Opportunity

Kent Historical Society - Reflections: Kent-Then and Now, 1900-1960

David M. Buerge - Renton, Where the Water took Wing

Flood History Sites

HistoryLink.org
A brief history of the Howard Hanson Dam, complete with photographs, timelines, related histories and personal accounts. HistoryLink is a free, authoritative and easily accesible online encyclopedia of Washington State history.
White River Valley Museum
An essay on the history of the Green (formerly White!) River Valley, with information on flood control, the Howard Hanson Dam, and those confusing river names. Located in Auburn’s Les Gove Park, the White River Valley Museum tells the story of South King County from the Native People, through the Settlers, and into the 20th Century through unique and fascinating exhibits, programs and publications. Open to the public Wed-Sun from noon to 4pm.

Preparing for a Flood

This guide provides resources and information in three areas:

Before a Flood

During a Flood

After a Flood

Green River Valley Flood Maps

Provided by the Army Corps of Engineers, the maps show five different scenarios. Please select from the following:

Flow rate of 13,900 cubic feet per second (cfs) map
Flow rate of 17,600 cubic feet per second (cfs) map
Flow rate of 19,500 cubic feet per second (cfs) map
Flow rate of 25,000 cubic feet per second (cfs) map
Flow rate of 25,000 cubic feet per second (cfs) map with a Levee Failure at 180th Street.

Note: All Army Corps of Engineers Maps are 11x17 in size. For more detailed maps or maps of the Middle Green River, please click here.

Specific City Flood Maps:

Auburn Flood Map
Kent Flood Map

Tukwila Flood Map

Renton Flood Maps of four different flow rates: (13900cfs), (17600cfs), (19500cfs) and (25000cfs).

Flood maps are also available at many King County Library locations in South King County.

A Bit of History About the Howard Hanson Dam

Prior to the 1962 dedication of the Howard Hanson Dam, floods inundated the Green River Valley nearly every year. Local flood control initiatives in the 1920s and 30s proved unsuccessful and South King County residents petitioned the U.S. War Department (Army Corps of Engineers) to provide assistance. Fishing interests, a World War and a lack of finances all delayed initial construction. Howard A. Hanson, a Seattle attorney, civil engineer and civic leader finally succeeded in the campaign to secure funding for the dam project and in 1959 construction began in the Eagle Gorge area.

The dam construction included two side abutments – hillside anchors – and planners anticipated routine, modest abutment seepage. However, in January 2009, a record high level of water behind the dam revealed two depressions causing unusually high abutment seepage rates. Although the dam itself is not at risk of failing, water retention is compromised and until an anticipated 3-5 year permanent fix is completed, the dam’s retention capability will be compromised. Estimates, after a temporary grout fix, state that there is a 1 in 25 chance of flooding in the Green River Valley this season.