On Sunday, August 22, a sinkhole appeared on Thomas Road between Dobson and Longmore roads and caused curiosity for many Salt River Pima-Maricopa Indian Community members. The Salt River Police Department posted a notice about the sinkhole on Facebook to caution residents against driving in that area. 

According to SRPMIC Public Works Road Maintenance Supervisor Gregg Bacome, the recent heavy rains infiltrated cracks in the asphalt, creating voids that eventually led to a sinkhole. 

“What happens is the cracks in the asphalt allowed the water to infiltrate through the asphalt, and when that happens it erodes the sub-base of the roadway and creates an air pocket underneath the asphalt,” said Bacome. “When a heavy piece of machinery or vehicle gets too heavy for that air pocket, the asphalt falls through because there is nothing underneath supporting it.”

The sinkhole started out at 2 feet in diameter by 18 inches deep, and after the Public Works Roads Division opened it up for excavation, the hole ended up measuring 20 feet by 14 feet. 

“When we have a situation like this, we excavate the material until we get rid of all the voids. When we feel comfortable with the stability of the dirt there, we put in one-sack slurry (controlled low-strength material). That hardens the dirt up, creating a bridge underneath the asphalt to equally distribute the weight for cars going over it,” said Bacome. 

If SRPMIC members see anything out of the ordinary on the roadways, they can call Salt River Public Works Customer Service at (480) 362-5600 from Monday to Friday, 8 a.m. to 5 p.m. After hours or on weekends, call Salt River Dispatch at (480) 850-9230 so they can contact the on-call workers from the Public Works Department. 

“If you see something, say something,” said Bacome. “We have an on-call program where we respond to emergencies after hours. When this sinkhole occurred, Dispatch did contact us and we were able to get a crew out and secure the roadway until we could make an assessment the following day.”