Maricopa County officials are watching the streets after monsoon rains opened a fissure south of Queen Creek that cracked a road and threatens to damage others.
The Maricopa County Department of Transportation is monitoring a ground fissure that cracked San Tan Boulevard east of Sossaman Road after rains last weekend.
Roger Ball, spokesman for the Transportation Department, said the crack is small for now, and county workers placed steel plates over it to allow road travel to continue in the area.
Several fissures — subsidence cracks caused by groundwater harvesting and exposed during heavy rains — appeared over the past week in the Queen Creek area, prompting attention to how they are affecting roads, Ball said.
Fissures damaging roads is uncharted territory for Maricopa County, but engineers did minor work in the area Tuesday and plan to do more comprehensive study next week, he said.
Out of the 2,600 miles of roadway the county maintains, this is the first issue of fissures interfering with the roads, Ball said.
“The big concern for all of us is that we don’t exactly know where each and every fissure is,” he said. “This is one of those things where as you dig, you may find more. The magnitude of the fissures in this area makes it unusual for us.”
Ball urges area residents to report fissures.
Maricopa County officials said legislation enacted last year that requires the Arizona Geological Survey to map fissures around the state is helping in its quest to research and respond to fissure issues.
Mapping recently completed by the Arizona Geological Survey is the first step in preparing more highly detailed fissure maps of specific areas. Those maps will be completed over the next five years.
Geological Survey officials said the first detailed fissure map due out in the next year will focus on the area where the fissure damaged San Tan Boulevard: the Chandler Heights area, an unincorporated area of Maricopa County south of Queen Creek.
That area was selected for the first map because of its growth and the need to show developers and residents where fissures could pose a hazard, Geological Survey officials said.