About
This project will help stabilize the Arizona Inn Landslide area, located along the southern Oregon coast about 10 miles south of Port Orford, by completing a drainage system that will remove groundwater from the hillside.
In January 2023, a landslide closed U.S. 101 through this area for several days. In response, ODOT developed a plan to stabilize the hillside by installing a new drainage system consisting of an array of pipes that would connect to a giant shaft. The pipes would drain water from the hillside, and the shaft would act as a giant catch basin, collecting groundwater and discharging it to the ocean.
Over the following year, ODOT worked with contractors on Phase 1, which installed the drainage pipes on the hillside east of the highway.
Current project: Construction began on Phase 2 in April 2025 and will continue for about 18 months. Contractors will dig a shaft about 200 feet deep and 20 feet in diameter at the south end of the slide area. The shaft will be located on the west side of the highway and near a large rock formation that has, historically, seen little ground movement from nearby landslides. The network of drainage pipes will then be connected to the shaft.
A similar drainage system had been built following a large landslide in the 1990s. However, the shaft for that system was located within the landslide area and had been damaged by years of ground movement. The new shaft will be less vulnerable to similar damage since it will be built outside the main landslide footprint.
Background: The landslide area, which is a half mile north of the Arizona Beach Recreation Area, has been a problem since the highway opened in the 1920s. Large landslides closed the highway in 1938, 1954, 1978 and 1993. Smaller landslides have required frequent lane closures and emergency repairs.
No local detour: U.S. 101 is a lifeline route for those living along the southern Oregon coast. When the highway is closed at the Arizona Landslide, drivers traveling between Port Orford and Gold Beach must detour five hours and 280-miles along Oregon 42, Interstate 5 and U.S. 199.
Future project: Prior to the 2023 landslide, U.S. 101 through this area consisted of three lanes, one southbound lane and two northbound lanes. Emergency repairs after the landslide only reestablished one northbound lane through this area. An upcoming project will extend the northbound passing lane through the landslide area.
Location
U.S. 101
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U.S. 101 (Oregon Coast Highway), milepost 312.4, about 10 miles south of Port Orford or 15 miles north of Gold Beach.
Cost and Funding
Successful bid amount: $18,304,129.00 (for bid opening Nov. 21, 2024)
Contractor
Condon-Johnson & Associates, Inc. (Oakland, California)
Additional Information
Flickr album: U.S. 101 Arizona Inn Landslide and emergency road repairs, 2023
Flickr album: U.S. 101: Arizona Inn Landslide Mitigation Project (Phase 2), 2025-2026