Green River’s Hanson Dam performs well during heavy rain

The Howard Hanson Dam performed well during recent heavy rains to help control flooding along the Green River, according to the U.S. Army Corps of Engineers.

  • BY Wire Service
  • Wednesday, January 19, 2011 7:14pm
  • News
The reservoir behind the Green River's Howard Hanson Dam as seen in a 2009 file photo. The U.S. Army Corps of Engineers stores water behind the dam to help prevent flooding along the river.

The reservoir behind the Green River's Howard Hanson Dam as seen in a 2009 file photo. The U.S. Army Corps of Engineers stores water behind the dam to help prevent flooding along the river.

The Howard Hanson Dam performed well during recent heavy rains to help control flooding along the Green River, according to the U.S. Army Corps of Engineers.

The corps held water behind the dam that pushed the reservoir level to a peak of 1,155 feet above sea level. That is above an elevation (1,147 feet) that triggers increased on-site monitoring to ensure dam safety.

Despite the extra water storage, engineers said the dam performed well, according to a Jan. 19 corps media release.

The corps has held Hanson Dam outflows to around 7,000 cubic feet per second, while inflows peaked above 20,000 cfs. The corps is operating the dam to keep flows along the Green River at Auburn about 10,500 cubic feet per second, below the 12,000 cfs level of concern for levees from Auburn downstream to Kent, Tukwila and Renton.

Levee patrol teams remained out Jan. 19 in the Green River basin monitoring conditions and communicating what they see back to the Army Corps Seattle District’s reservoir control center and emergency operations center.

Flows above or near levels of 9,000 cfs along the Green River trigger the corps to monitor levees 24 hours a day.

There is a risk of flooding for property owners along the non-leveed middle Green basin, the rural portion of the river upstream from Auburn to Hanson Dam. Flows above 9,000 cubic feet per second as measured at the Auburn gage, triggered a flood warning from the National Weather Service due to flooding concerns in the Middle Green River.

These flows do not present flooding concerns for the more highly populated areas downstream, including Auburn, Kent, Tukwila or Renton.

The corps works to keep the reservoir empty at Hanson Dam along the Green River until storage is required for flood risk management. The dam had an empty reservoir on Jan. 14.

The corps has lowered the threat of Green River flooding this winter to 1 in 60 from 1 in 33 last year because of installation of a grout curtain that stood up to summer tests to allow for more storage capacity in the reservoir behind the dam.

Repairs were needed at the dam after a January 2009 storm damaged an abutment next to the dam.

The odds of flooding are 1 in 140 when the dam is fully operational. An additional $44 million in repairs, including more drains and the extension of the existing drainage tunnel to put the dam back at its top level, will not be completed until late 2012.


Talk to us

Please share your story tips by emailing editor@kentreporter.com.

To share your opinion for publication, submit a letter through our website https://www.kentreporter.com/submit-letter/. Include your name, address and daytime phone number. (We’ll only publish your name and hometown.) Please keep letters to 300 words or less.

More in News

Kent police investigate fatal two-vehicle collision

The collision killed a woman and left a 45-year-old Tacoma driver, suspected of intoxication at the time of the crash, hospitalized.

Competing for the 8th Congressional District: Carmen Goers, left, and Kim Schrier. COURTESY PHOTOS
Adam Smith and Kim Schrier will retain Congress seats | Election 2024

Smith represents the 9th Congressional District and Schrier represents the 8th Congressional District.

Courtesy of Democratic Caucus
Pictured left to right: Sen. Bob Hasegawa (D), Rep. David Hackney, and Rep. Steve Bergquist
Democratic incumbents in lead for 11th Legislative District

Bob Hasegawa, David Hackney and Steve Bergquist have strong leads, with Hasegawa and Hackney running unopposed.

Debra Entenman and Kyle Lyebyedyev. File photos
Entenman and Stearns lead in 47th District | Election 2024

The district includes Kent, Covington and Auburn.

File photo
Kent School District levy is failing at the polls | Election 2024

Early election results show voters rejecting the proposed Capital Projects and Technology Levy.

Larry Best, a customer coordinator for quality assurance who has worked at Boeing for 38 years, stands outside of Angel of the Winds Arena with a “vote no” sign on Monday in Everett. (Olivia Vanni / The Herald)
Boeing Machinists approve contract, ending 52-day strike

After voting no twice, 59% of union members approved the latest contract.

Photos from the United States Attorney's Office Western District of Washington press release.
Kent man arrested in connection to violent drug trafficking gang investigation

Law enforcement seized more than 20 kilograms of fentanyl, 60 firearms, and more than $130,000 in cash.

Courtesy Photo, King County
Son accused of fatally shooting mother’s boyfriend in Kent back in jail

Dondre Butler has 3 violations in 13 months of electronic home detention after charged with murder in 2022

t
Kent Police targeted street patrols result in arrest of two felons

One driver spotted in a vehicle with no plates; another driver reportedly in a stolen vehicle

t
Kent cold case murder suspect back in state after governor’s warrant | Update

Kenneth Kundert fought extradition from Arkansas after August arrest in 1980 killing of Dorothy Silzel

t
City of Kent eyes November opening for Reith Road roundabouts

Two more roundabouts will bring total in city to six; three more in future plans