Date:  Monday, December 24, 2007

Contact: Greg Phipps, WSDOT Communications, 206.440-4702 (Shoreline)
Colleen Gants, WSDOT Communications, 206.465.2311 (Cell)

RENTON – Not wanting to take any chances, WSDOT contractor, Tri-State Construction, worked non-stop over the weekend to complete all three runs of pipe in the new emergency pumping system to protect I-405 from a heavy rainstorm.

WSDOT now has two pumping systems comprised of three pipes to the south and one pipe to the north to help drain Thunder Hills Creek and prevent the water from going under or over I-405 near Benson Road.

“We won’t be totally out of the woods until we get that new culvert under I-405,” said Lisa Hodgson, WSDOT Project Engineer. “We will begin that work in January. But for now, we have a system in place that will help prevent a crisis.”

On Dec. 3, record-breaking rain moved through Puget Sound and caused a sinkhole to develop adjacent to the southbound shoulder of I-405. Upon closer examination, engineers discovered the culvert under the freeway collapsed and more rain could put the roadway in jeopardy. To prevent Thunder Hills Creek run-off from doing any more damage, crews moved in quickly on Dec. 10 and began an elaborate operation to divert water to a nearby wetland.

On Wednesday, Dec. 19, heavy rain nearly overwhelmed the first phase of emergency pumping equipment. WSDOT incident response crews and Washington State Patrol troopers were called to the scene around 8:30 p.m. and were prepared to close the freeway if necessary.

“We did not want to be in that position again,” said Hodgson. “That’s why the contractor worked non-stop until all three runs of 2,000-foot long pipe were in place.”

In addition to the three runs of 24-inch pipe, WSDOT has a pumping and drainage system set up to send water north of the work. Fifteen giant pumps and generators are on site and WSDOT and contractor crews will check the area once an hour to make sure the system continues to work.

In the long-term, WSDOT is developing a design to replace the entire 400-foot long culvert that runs 60 feet under I-405. “This is not an easy or quiet job,” said Hodgson. “We have already started talking to local businesses and local governments about the work.” We hope to begin work in January.

For more information on the project, go to
www.wsdot.wa.gov/Projects/i405/RentonCulvertReplacement

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