Project overview
This project made repairs to the hillside next to State Route 109 north of Moclips on the Quinault Indian Nation.
What to expect
On Tuesday, Oct. 14, crews applied permanent pavement markings to the highway, completing major road work.
During construction, travelers saw temporary traffic lights alternating traffic on a single lane.
Crews worked to repair the hillside by removing vegetation, rock and debris. New drainage pipes were installed to filter water into the highway’s drainage system.
Location of the work zone on SR 109 north of Moclips.
SR 109 has a history of large debris slides triggered by powerful Pacific Northwest rainstorms. From December 2018 through January 2020, heavy rains caused a series of slides along the highway north of Moclips. Some of the slides blocked both lanes of the highway between milepost 33.76 and 33.87.
WSDOT geologists visited the site several times. The team collected samples, analyzed data and studied the geological history of the area. Planning began for a project to stabilize the hillside.
During the project, crews added support to the hillside by building quarry spalls. Quarry spalls are trenches filled with crushed rock. The quarry spalls will help improve drainage and prevent soil saturation. The geologists also recommended installing horizontal drainage pipes throughout the hillside. The pipes will collect water and empty into the highway’s drainage system. These improvements are intended to reduce the likelihood of future slides.