Project Title & Location
SR 520 W Lake Sammamish Parkway to SR 202 - Redmond

Project Description
This project will widen State Route 520 to eight lanes between the West Lake Sammamish Parkway Interchange and the State Route 202 Interchange. The widening includes auxiliary lanes, ramps and high occupancy vehicle (HOV) lanes.

Contractor/Consultant
CH2M-HILL was selected as the prime design consultant for this project (both Stages 3A and 3B).  Tri-State Construction has been selected as the prime construction contractor for the Flyover portion (Stage 3A).

Recent Progress
Construction for stage 3A (the flyover ramp) is in progress.

The Deviations and Channelization Plans for stage 3B have been approved and the Design Decision Package (DDP) is being finalized. Completion of the DDP has been delayed by approximately three months, and is now scheduled for completion in early 2008.

The Biological Assessment (BA) for stage 3B was completed in early October, and submitted for review and comment to the federal services on October 5th.

The JARPA and Shoreline Permit packages were submitted for review on October 29th, and we are continuing to work with the City of Redmond to resolve the issue of buffer impacts to Bear Creek.  WSDOT is proposing to mitigate for the permanent stream buffer impacts at an off-site location within the Bear Creek Basin and to enhance the functions of the remaining buffer within the project limits.

Recent updates to seismic design codes will impact both the project cost and schedule.  Preliminary estimates indicates that this could increase the bridge design time by 25% (2 to 3 months), bridge construction cost by 5%, and wall construction cost by 15%. We are working with our Bridge and Structures and Geotechnical groups to better determine these impacts.

Based on the latest cost estimate, the project is currently on schedule and within budget.  However, there are significant risks associated with the stream buffer and seismic design issues.  Project construction costs will be increasing due the the revised seismic codes, and additional design time will be needed. There is also a risk that the Advertisement date may be delayed by as much as a year if the Redmond City Council does not approve the proposed buffer mitigation and issue a Shoreline Permit.  This will result in additional inflation costs to the project.

Design Construction Impacts
Stage 3B will require lane, ramps, and roadway closures. The design team is looking into ways to minimize impact to the traveling public during the construction of stage 3B. 

Environmental Impacts / Compliance
WSDOT is working closely with City of Redmond, NMFS, USFW, and the MAP Team to provide water quality treatment and flow control for the project. The right of way constraints of Bear Creek and Marymoor Park and the low roadway elevations on SR 520 relative to the Sammamish River eliminate the use of many traditional BMPs.

Impacts to Traffic
The construction of the flyover ramp (stage 3A) is in progress. There will be intermittent lane closure on SR 202 as the bridge is completed.

There will also be lane and ramp closures during stage 3B.  Mitigation efforts will include a comprehensive public awareness campaign and implementing a detour route.

Planned vs. Actual Expenditures
(Total Project Cost)

Nickel funds included in above costs

2005 Transportation Partnership Account