On Dec. 3, 2007, heavy rainfall overwhelmed the culvert that carried Thunder Hills Creek beneath I-405 in Renton. The resulting rush of water created a sinkhole beneath the road surface, resulting in a collapse of a section of the culvert and threatening the stability of this section of the freeway. Crews made temporary repairs to fix the sinkhole and diverted water away from the culvert while they designed a replacement plan for the culvert to prevent significant damage to I-405 in the next storm.
In late March 2008 crews began work to install a new culvert underneath I-405. We originally expected to complete culvert installation by the end of July, but ran into problems with the tunnel boring machine. Crews resumed tunneling and culvert installation in October and the creek was running through the new culvert by the end of October.
The repairs stabilized the road for drivers and will protect agains future flooding that could threaten the stability of I-405.
| Protects Environment
During repairs crews used a pump and pipe system to divert Thunder Hills Creek into a wetland.
Partnerships & Cooperation
Crews began repairs on Dec. 13, 2007. On Dec. 23 they completed the temporary pump and pipe system that diverts Thunder Hills Creek around I-405.
In March 2008 we awarded the contract to Tri-State Construction. Replacement work began in June. In July the project was delayed by problems with the tunnel boring machine and we halted work to develop a plan to recover the machine by tunnelling from the east side of I-405. Tunnelling resumed in October and the creek was running through the new culvert by the end of October. Crews spent the first weeks of November removing the diversion system and restoring roadway barrier.
At WSDOT we seek to address the concerns of the tribal nations using the process outlined in Section 106 of The National Historic Preservation Act and the WSDOT Tribal Consultation Policy adopted in 2003 by the Transportation Commission as part of the WSDOT Centennial Accord Plan.
This project was funded through the following sources:
- Federal emergency funds - $7.9 million
- 2005 Transportation Partnership Package - $600,000
- Total funding available from all sources - $8.5 million
WSDOT Project Engineer Dave Lindberg
12277 134th Court N.E., Suite 200
Redmond, WA 98052
Phone: (425) 814-7104
WSDOT Communications Meghan Soptich
15700 Dayton Ave N
Shoreline, WA 98133
Phone: (206) 440-4704
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