The Federal Highway Administration has pledged $2 million in immediate aid that can be used to continue investigating the cause of a landslide on a stretch of U.S. 89 last month near Page, Ariz.

Photo courtesy ADOT
The landslide on Feb. 20 caused 500 ft of damage to U.S. 89 near Page, Ariz.
Photo courtesy Coconino County
The slide caused the roadway to drop by up to 6 ft in places.

The Arizona Dept. of Transportation requested the quick release of emergency relief funds from the FHWA after submitting an initial estimate of $35 million to complete repairs to the damaged stretch of highway.

The highway sustained approximately 500 ft of damage, including 150 ft of pavement that settled by up to 6 ft, after the Feb. 20 landslide. The northern Arizona road remains closed between the U.S. 89A junction near Bitter Springs to the S.R. 98 junction near Page.

Before ADOT can move forward with a design to potentially repair the damage, the agency must determine that the mountain slope has stabilized. The quick release funds will be used to assess the damage and slope stability, and conduct emergency operations.

The FHWA’s emergency relief program reimburses state and local agencies for the repair or reconstruction of highways, roads and bridges that are damaged in natural disasters and catastrophic failures.

“Our budget for emergencies is very limited, and local governments have even greater financial constraints with limited cash available to fund emergencies,” says Jennifer Toth, ADOT deputy director for transportation. “This initial allocation serves as a down payment on the overall emergency relief needs for U.S. 89.”

Last week, ADOT received environmental clearance for geotechnical engineers to begin drilling shafts to deploy inclinometers—plastic pipes that measure slope movement—beneath the ground surface.

“This is not a typical landslide,” says Steve Boschen, ADOT deputy state engineer of design. “It’s a deep-seated bedrock-type slip.”

In addition to inclinometers, ADOT is using extensometers above the ground to measure changes in tension from the bottom of the slope to the top, using a pulley device that has a 30-lb weight registered to a scale.

ADOT is also using LiDAR - a type of 3D laser scanning - to map the landslide from the ground.