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Project Title & Location
I-90 - Snoqualmie Pass East - Hyak to Keechelus Dam
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Project Description
This project will improve I-90 to provide a safer, more efficient six-lane freeway from Hyak to Keechelus Dam. This project is the first of several projects that will address concerns along I-90 from Hyak to Easton. Avalanche closures and hazards due to rockfall will be minimized. Aging pavement will be replaced to provide a smoother ride. Expanded bridges and culverts will minimize wildlife collisions by providing safer crossings.
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Contractor/Consultant
General Engineering Consultant: URS Corporation - Headquartered in San Francisco, CA
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Recent Progress
Geotechnical exploration is proceeding and the 2007 planned exploration work should be completed next quarter. Gravel samples from the pit site located in the Keechelus Lake near Rocky Run Creek are being analyzed and the results should be back in winter 2008. Design work continues on bridges for Gold Creek, Rocky Run Creek, and the snowshed.
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Design Construction Impacts
Geotechnical investigations have confirmed the presence of scarps (tension cracks) upslope of I-90 on Slide Curve. To address the issue of scarps the roadway geometry is being raised around Slide Curve. Final design is pending based on the outcome of field investigations.
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Environmental Impacts / Compliance
A Pre-Signatory Agency Committee (SAC) meeting was held in October; SAC concurrence is anticipated by Feb 2008. ESA Biological Assessment will be submitted in Nov 2007. Wetland mitigation is under review with Ecology and Corps of Engineers.
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Impacts to Traffic
Rolling slowdowns are planned to occur regularly on weekday mornings through November for helicopter support of drilling operations on the slopes above the highway. Lane closures have not been required.
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