After several inches of rain last week, Arizona Department of Transportation crews are closely monitoring the landslide area on Highway 87 near Slate Creek. Crews recently noticed movement on the slope.
This has engineers concerned because according to a study by the Arizona Geological Survey (AZGS), the March 21 landslide that closed Highway 87 for nearly a week and may cost $18 million to repair could have been triggered, in part, by heavy rainfall.
On Dec. 17, ADOT engineers noticed that a mound of soil had developed on the side of the hill, west of the highway. ADOT crews were positioned at observation posts throughout the hill to monitor the slope around the clock while consulting engineers and construction crews assessed any changes to the slope.
So far, the new mound is not affecting traffic or the roadway.
The March landslide caused nearly 45 feet of the highway’s southbound lanes to buckle and shift. The roadway was closed for six days and southbound lanes were reopened in late May.
Crews have already installed a 4-foot-wide drainage pipe, concrete pilings and monitoring devices to measure any future movement in phase one of the project.
During phase two, which is expected to begin in early spring, a 20-foot-high retaining wall will be created using the pilings on the west side of Highway 87 and additional erosion-control measures are planned for both sides of the highway.
Call 511 or visit www.az511.gov for highway conditions.