- Northbound I-5 traffic is reduced to two lanes and detoured onto a bypass lane just north of Starbird Road. The speed limit is reduced to 60 mph.
- These changes are in place while contractor crews build a new northbound I-5 bridge deck over Fisher Creek.
- Construction began in May 2016. Work is scheduled to be completed fall 2017.
Why is WSDOT
building bridges for I-5 over Fisher Creek?
Fisher Creek, located about five miles south of Mount Vernon in Skagit County, passes under I-5 in an 8-foot diameter culvert. The culvert is rusting out and some of the soil west of the southbound paved shoulder is washing away. It also creates a barrier to fish passage because the water moves too fast for fish at high water times, and is too shallow during low water times. In 2013, the U.S. District Court for Western Washington ruled that the state must remove culverts that block fish passage under state roads. Fisher Creek is one of more than 1,000 in this state subject to this ruling. Removing the culvert, building twin 110-foot-long bridges and reconstructing the creek bed to a more natural state will allow for better fish passage.
Why not put in a new culvert? The normal width of the creek at peak flow is about 30 feet, which is too wide to fit into a standard culvert.
What are the challenges to building bridges for I-5 over Fisher Creek?
- Keeping traffic moving: I-5 will remain open in both directions during bridge construction. WSDOT contractor crews will start the project by building two bypass lanes in the I-5 median. When the bypass lanes are complete, southbound traffic will shift onto these lanes so the new southbound bridge can be built. When the bridge is finished, southbound traffic will return to the regular lanes and northbound traffic will shift to the bypass. When that bridge is complete, northbound traffic will return to the regular lanes and the bypass will be removed.
- Narrowing the interstate from three to two lanes: At Fisher Creek, I-5 has three lanes in each direction that are separated by a wide median. Traffic in one direction at a time will be narrowed from three lanes to two and the speed limit will be reduced from 70 to 60 mph approaching the bypass lanes in the I-5 median. Two lanes are sufficient for the 59,000 average daily trips that use this section of I-5.
- Working near wetlands: Contractor crews will need to be careful working near and above the creek to keep any construction material and sediment out of the creek and wetlands.
What should drivers expect?
- Lane reductions: Drivers should be prepared for lane reductions to start well before the construction zones. I-5 will narrow from three lanes to two, then expand back to three once motorists pass the work zone.
- Reduced speeds: During construction, the speed limit through the work zone will be reduced from 70 to 60 mph.
- Much heavier congestion than usual during the 2017 Skagit Valley Tulip Festival: Northbound I-5 will be reduced to two lanes near Fisher Creek in the first half of 2017. This includes during the Skagit Valley Tulip Festival in April. Tulip traffic often is heavy; drivers should be prepared for even heavier congestion on I-5. Drivers may want to use alternate routes during the 2017 festival.
How will the work be performed?
While southbound traffic is diverted on to the bypass lanes, crews will remove a section of all three southbound lanes and shoulders of I-5, remove some of the underlying fill, and build a new bridge. When the southbound bridge is complete and traffic has been returned to the regular lanes, crews will divert northbound traffic onto the two median bypass lanes and follow the same steps to build the northbound bridge. Once both bridges are complete, the crews will remove the bypass lanes, remove the remaining fill and existing culvert and build a more natural creek bed for Fisher Creek. They’ll also plant the new creek banks with native vegetation.
The End Result
Building two bridges to replace the Fisher Creek culvert will help restore the creek to a natural state, open up more than 17 miles of fish habitat for salmon and steelhead, and comply with the U.S. District Court ruling.
- This project will improve fish passage and open up additional salmon and steelhead habitat.
- The work will help WSDOT comply with the U.S. District Court ruling regarding fish passage.
What is the project timeline?
Winter 2016: Advertise project for competitive bidding.
Spring 2016: Begin construction of the bypass lanes in I-5 median.
Summer 2016: Temporarily divert southbound I-5 to bypass lanes.
Late fall 2016: Return traffic to southbound I-5 regular lanes.
Winter/spring 2017: Temporarily divert northbound I-5 to bypass lanes
Summer 2017: Return traffic to northbound I-5 regular lanes.
Fall 2017: Remove bypass lanes, restore Fisher Creek bed.
|Financial Data for PIN 100560D
||Amount ($ in thousands)
|2003 Gas Tax (Nickel Funding)
|2005 Gas Tax (TPA)
|Pre-Existing Funds (PEF)
Project signage will reflect the cost of construction engineering, project bid award and sales tax.
How can I get more information?
WSDOT Project Engineer
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