Arizona DOT estimates of landslide repair on I-89: two years, $40 million

By Land Line staff | Friday, July 12, 2013

The proposed solution to repair and preserve a stretch of Interstate 89 in northern Arizona could take more than two years to implement, according to a news release from the state Department of Transportation.

Photo courtesy of Arizona DOT

A Feb. 20 landslide on the mountain slope of Echo Cliffs gouged a 150-foot-long crack into the highway about 25 miles south of Page.

A $40 million plan to cut back the mountain slope and build a gravity-buttressed retaining wall is thought to be the best long-term solution, according to a geotechnical investigation commissioned by the state.

“The biggest thing is going to be (securing) the right-of-way and environmental clearance,” said Dustin Krugel, a spokesman with the transportation department. “Right now we’re projecting 12 to 18 months on that.”

Krugel said those clearances are necessary because the state plans to move the highway 60 feet east, away from the area of the landslide. Once the clearances are acquired, Krugel said the actual road construction will take an estimated six to 12 months.

A Feb. 20 landslide on the mountain slope of Echo Cliffs gouged a 150-foot-long crack into the highway about 25 miles south of Page. Reports of the scene that day said the road split in places and was divided by a deep fissure. U.S. 89 has been closed north of Bitter Springs and south of Page since.

A 463-page geotechnical report commissioned by the DOT stated the landslide was a reactivation of a small portion of an ancient landslide. The active landslide is approximately 135 feet below the roadway and measures approximately 1,200 long at the base of the slope.

The report listed several alternatives for the ultimate repair of U.S. 89, but the construction of a landslide buttress and upslope lane adjustment was considered the most feasible. The buttress, a wall-like support structure composed of rock, would be built at the base of the slope and the highway travel lanes would be moved farther to the east by creating a new cut into the existing slope in the Echo Cliffs.
 
ADOT is expected to formally request additional federal aid to fund the repair of U.S. 89 through the Federal Highway Administration’s Emergency Relief program, which reimburses state and local jurisdictions for the repair or reconstruction of highways, roads and bridges damaged in natural disasters and catastrophic failures.

The agency already received $35 million in federal aid to pave Navajo Route 20 and establish it as a shorter detour route for motorists until repairs are complete on U.S. 89. N20 runs parallel to US 89 and will significantly reduce travel time for motorists heading to and from Page and the Lake Powell. Detour construction started in late May on N20 and is scheduled to be completed in August.

The current detour established for drivers is using U.S. 160 (Tuba City exit) and State Route 98, which is approximately 115 miles long and 45 miles longer than the direct U.S. 89 route. Drivers also have the option to take U.S. 89A north to Marble Canyon toward Fredonia to reconnect to U.S. 89 in Kanab, Utah.
 
ADOT has launched a range of communication tools, including a website dedicated to keeping the public informed about the status of the closure and alternate travel routes.

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