Drivers traveling from Benson to St. David and Tombstone are having to take a 20-mile detour because of a road closure on Arizona 80 about 5 miles south of Interstate 10.
The closure, which began Monday afternoon, is to allow Arizona Department of Transportation work crews to repair soil erosion under the roadway, the Arizona Department of Transportation said.
The closed section is between Mileposts 298 and 299. Drivers heading south on 80 toward St. David must now detour by first taking Arizona 90 south of Benson and then Arizona 82 east from 90 to 80 north of Tombstone.
The Cochise County Sheriff’s Department said it had been advised of road fissures and sinkholes along Arizona 80 in the area of Apache Powder Road.
The transportation department pinned the blame for the erosion on a clogged drainage pipe that allowed extra water from storm runoff to enter the roadway, leading to soft spots under it.
ADOT maintenance crews have been working since Monday to replace the storm drain and complete pavement repairs. The work is expected to continue for several days.
Crews are monitoring locations where soil erosion appears to have occurred in the general area. While no other areas appear to be an immediate concern, crews will take preventive measures as needed to head off drainage-related road damage, said Garin Groff, an ADOT spokesman.
Earlier this month, a two-mile stretch of U.S. 191 south of Willcox was closed for a week by cracking that state scientists said could have been partially caused by land subsidence, the sinking of the ground caused by overpumping of groundwater. That’s an area containing lots of agriculture with a history of heavy groundwater use.
But in the Benson-St. David area, subsidence is “very minimal,” less than one-tenth of an inch per year, said Brian Conway, a hydrologist who manages the Arizona Department of Water Resources’ subsidence unit.
“Everything’s been so dry that once they get moisture in there, the cracks open up from natural drying and wetting of the soils,” Conway said.