Project overview
On Tuesday, Feb. 23, 2021, due to roadway settlement caused by heavy rainfall, both directions of State Route 401 (also known as the Lewis and Clark Trail Highway) between the Astoria-Megler Bridge and Naselle were closed.
In spring 2021, emergency contractor crews were able to reopen a single-lane of the highway near milepost 5.0, allowing travelers access through the area by alternating intermittently through a single-lane with an automated traffic signal.
In late summer 2023, contractor crews will begin work to stabilize the slope, improve drainage and repair the roadway. Additionally, as part of this project, contractor crews will make improvements to the Knappton Boat Launch located off of SR 401 along the Columbia River near milepost 4.0. Contractor crews will regrade the gravel boat launch site and parking area and replace vandalized signs.
What to expect
**UPDATE 10-1-2024**
Crews will take advantage of the planting window by adding landscaping and planting trees along the slope running alongside SR 401. Trees and landscaping play an important key role in slope stabilization by anchoring the soil with root systems, helping to prevent erosion and reducing the risk of debris and mud slides. Contractor crews will utilize alternating single lane closures with flaggers.
As part of this project, contractor crews will make improvements to the Knappton Boat Launch located off of SR 401 along the Columbia River. Contractor crews will regrade the gravel boat launch and parking area and replace vandalized signs.
In late summer 2023, contractor crews will begin work to stabilize the slope, improve drainage and repair the roadway. Additionally, as part of this project, contractor crews will make improvements to the Knappton Boat Launch located off of SR 401 along the Columbia River near milepost 4.0. Contractor crews will regrade the gravel boat launch and parking area and replace vandalized signs.
Needs & benefits
Washington State is known for its green trees, wet climate and stunning mountainous landscapes. With our proactive approach to slope stabilization efforts, the Washington State Department of Transportation (WSDOT) is constantly evaluating slopes and hillsides across the state. Among these slopes we're focusing on the section of highway above SR 401 between milepost 4.5-4.65 - this area has been identified as an unstable slope adjacent to our state highways.
Recently this particular slope was re-evaluated and it ranked as a high-priority repair project. Had the slope not suddenly failed, a planned repair project for this section was scheduled for the next few years.
Following the failure of the slope in Feb. 2021, to keep travelers moving safely through this area, the two lanes of travel were reduced down to a single-lane. This traffic configuration will remain in place until construction is complete and the roadway is fully reopen.
In summer 2023, the project went through a competitive bidding process and was awarded to Rognlin's, Inc. on July 21, 2023. Starting in late summer 2023, our contractor will begin essential work to stabilize the slope, improve drainage and carry out much-needed repairs to restore and rebuild the roadway.
Additionally, as part of this comprehensive project, our contractor crews will also be making improvements to the Knappton Boat Launch, a popular site located off SR 401 along the picturesque Columbia River. Among the planned enhancements, we will regrade the gravel boat launch area and parking area, and replace any vandalized signs, enhancing the overall accessibility and attractiveness of this beloved spot.
We understand the importance of this route to the nearby community and to those visiting our state, and we will make every effort to complete the improvements promptly and efficiently. Stay tuned for further updates as the project progresses, and thank you for your patience and understanding during this critical phase of improvements to SR 401.