Plan for around-the-clock alternating traffic on SR 109 north of Moclips beginning July 28

Work intended to help prevent debris slides along the highway

TAHOLAH – Travelers will soon see reduced speeds and one-way traffic on State Route 109 near Moclips, as a project designed to help prevent long-term highway closures gets underway.

Beginning Monday, July 28, contractor crews working for the Washington State Department of Transportation will activate temporary traffic lights on SR 109. The traffic lights will alternate travelers one direction at a time around the clock near Moclips Highway. This allows crews to remove vegetation overgrowth, rocks and other debris from the hillside.

The speed limit through the area will be reduced from 50 to 25 mph for about a half-mile stretch between mileposts 33 and 34. Both the lower speed limit and one-way traffic are expected to remain in place through mid-October.

After clearing the hillside, crews will reinforce it with trenches filled with crushed rocks. These rocks will add support and stability. Crews will also install horizontal drainage pipes within the hill above the highway, then plant trees and shrubs around the work zone.

Why this is needed

This section of SR 109 has a history of large debris slides. They are typically triggered by powerful Pacific Northwest rainstorms. From December 2018 through January 2020, heavy rains caused a series of slides that closed the highway multiple times. These improvements are intended to reduce the likelihood of future slides by improving drainage and preventing soil saturation.