Tukwila Flood Watch Information

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Howard Hanson Dam Flood Watch Information

Following a record high level of water behind Howard Hanson Dam in January 2009, the U.S. Army Corps of Engineers became concerned after discovery of two depressions on the right abutment, increased water levels in groundwater monitoring wells, and the appearance of sediment-laden water entering the abutment drainage tunnel and restricted flood storage as a result. The reduced capacity has increased the risk of flooding in the Green River Valley.

The U.S. Army Corps of Engineers announced in early November that the interim repairs at Howard Hanson Dam have reduced the risk of flooding along the Green River from 1 in 3 to 1 in 25. The Corps is wrapping up the drainage tunnel and grout curtain projects at Howard Hanson Dam that Corps staff and contractors have been working on 6 days a week, 24 hours a day since summer.

Potential impact of the restrictions on the flood storage capacity is increased flood risk to the Green River valley below the dam. Should a major flood event occur with the temporary restrictions on the pool level for flood storage, it is possible that levees in the lower valley could be overtopped. The Corps will continuously reassess the pool restriction as conditions change and may raise or change the restriction on pool elevation after careful deliberation.

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Live in Tukwila but work in another valley city (or work in Tukwila but live in another valley city)? Use these links to sign up for that city’s notification and warning system:

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Train-the-Trainer Program

The City of Tukwila is conducting several meetings for business community members regarding the most current conditions at the Green River’s Howard Hanson Dam. These meetings will be in a “Train-the-trainer” format to familiarize someone from each agency with the materials provided and allow them to return to their business and train employees and colleagues in the 5 Flood Safety Steps.

Use this page for information on future meetings and to download materials for use when presenting the 5 Flood Safety Steps to your business or neighborhood.

View the Train-the-Trainer Page

Flood Mitigation Photos

News Updates

3/9/10

Engineers At Howard Hanson Dam Begin To Raise Reservoir For Additional Water Supply Mission

The Corps have begun to slowly allow water levels to rise within Howard Hanson Dam’s reservoir for the annual spring fill of the reservoir. This operation mimics normal spring operations. Read the Entire Press Release...

12/18/09

Free Sandbag Materials Now Available for Tukwila Citizens

Sandbag materials can now be picked up free of charge at two Tukwila locations:

The materials will be available for pickup at the following times:
Weekdays: 7:00am - 3:30pm

Special thanks to the King County Flood Control District with support by the U.S. Army Corps of Engineers for providing all of the necessary materials. For more information please visit the King County Sandbag Distribution Website.

11/6/09

Army Corps of Engineers sees interim work on Howard Hanson Dam reducing Green River Valley Flood Risk

The U.S. Army Corps of Engineers announced Thursday that the interim repairs at Howard Hanson Dam have reduced the risk of flooding along the Green River from 1 in 3 to 1 in 25. The Corps is wrapping up the drainage tunnel and grout curtain projects at Howard Hanson Dam that Corps staff and contractors have been working on 6 days a week, 24 hours a day since summer. Read the Entire Press Release...

11/5/09

Unfair Business Practices Reported Relating To Flood Preparations

Tukwila Mayor Jim Haggerton and Southwest King County Chamber Executive Director Nancy Hinthorne are urging residents to be aware that some unfair business practices have been reported relating to flood preparations.

City officials recommend using a contractor who is licensed and bonded as required by Washington State law. Also, when selecting a contractor, be sure to ask them about their familiarity with Tukwila City Codes and procedures, and their Tukwila business license number. Read the Entire Release...

10/2/09

First shipment of temporary measures to decrease flood risk in the Green River Valley arrives in Tukwila

The latest development in the coordinated effort between the U.S. Army Corps & South King County cities is the delivery Thursday to the city of Tukwila of the first loads of the $3.2 million in temporary measure pre-flood support to the Green River Valley by the Corps. A semi-trailer full of giant flood-water defense systems, also known as HESCO containers arrived Thursday afternoon. Read the entire article....