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September 11, 2003
Image courtesy of WSDOT
WSDOT may create a wetlands restoration site to capture surface water upstream from new lanes planned for Interstate 405. Watershed-based planning is thought to be more cost-effective than traditional site mitigations, such as detention ponds.
Thanks to the nickel gas tax increase approved earlier this year by the state Legislature, environmental and engineering work has begun on three key Interstate 405 congestion relief and bus rapid transit projects.
As part of a group of “nickel projects” around the state, the $485 million on I-405 will address traffic congestion hot spots in Renton, Bellevue and Kirkland.
WSDOT, the Federal Highway Administration, and the Federal Transit Administration are holding a public scoping meeting to listen to concerns and issues to be addressed in the North Renton environmental assessment.
Kennydale Elementary cafeteria
1700 N.E. 28th St., Renton
The state Department of Transportation’s I-405 team has created a business plan to deliver the nickel projects and a 10-year implementation plan consistent with the corridor vision defined by the community during a two-year environmental impact statement process. That vision was approved last year by the Federal Highway Administration and Federal Transit Administration, and has been nationally recognized as a model for regional consensus building.
Three nickel projects are planned for the I-405 corridor:
South Bellevue area: Adds one new northbound lane from Interstate 90 to Southeast Eighth Street, and one new southbound lane from Northeast Fourth to I-90, rebuilding the Wilburton Tunnel.
Kirkland area: Adds one new northbound lane between Northeast 70th Street and Northeast 124th Street, and one new southbound lane between state Route 522 and state Route 520.
The three nickel projects have been designed to:
The I-405 projects are being managed by WSDOT staff and a general engineering consultant.
New lanes on Interstate 405 will create surface water runoff that must be captured and cleaned. While stormwater detention ponds can capture and store water runoff before it reaches a stream system, they are expensive to build and focus only on minimizing negative impacts and providing the minimum required benefits.
The I-405 project team is instead working with resource agencies to explore an idea to create a wetlands restoration site that captures surface water upstream from the highway and detains it in a more natural environment. This method enhances the watershed and can achieve additional environmental benefits at the same or lower cost.
Benefits of watershed-based planning:
The general engineering consultant is led by HNTB, with major partners HDR and Parsons Transportation Group. Others include Anchor Environmental, Certified Land Services, David Downs, Lund Consulting, McGowan Environmental, Mirai Associates, PRR, Wilbur Smith Associates and Wilkinson Ferrari & Co.
In addition to the general engineering consultant, the I-405 team is targeting $6 million for on-call agreements through WSDOT’s urban corridors office. A list of on-call contracts are currently being filled, largely for specialty environmental and engineering-related contracts such as geotechnical, surveying, right-of-way and architecture.
WSDOT is accountable to ensure I-405’s role as a functional urban highway that moves people and freight efficiently. Engineers are seeking the most cost-effective, safe and environmentally sensitive approach to building the nickel projects to ensure they provide the greatest public benefit.
The final programmatic environmental impact statement (EIS) and a federal record of decision, adopted in 2002, was based on a landmark regional agreement involving all of the local government jurisdictions along the corridor and significant public involvement.
Building from the programmatic EIS, the I-405 environmental team is moving forward with project-specific environmental assessments for individual sections of the corridor as engineering design is developed. These include environmental discipline reports, Endangered Species Act biological assessments, early action environmental investments, and a corridorwide environmental program.
At the same time the environmental team is preparing environmental assessments for the nickel projects, the team is also assessing nearby affected areas that may be included in future funding packages, such as the regional transportation improvement district, so that future planned highway improvement projects can get started earlier.
This is just one way the I-405 project is organized to deliver the most efficient and long-term benefits to the public. As the environmental assessments are completed — beginning in 2005 — design-build contracts will go to bid for final design and construction.
Craig Stone is the Interstate 405 project director for the state Department of Transportation.