Call it the “Son of Sinkhole.”
Another gap opened on Bob Galbreath Road near Clinton during the weekend, right next to the last one.
“We were as surprised as anyone when the call came in,” Randy Brackett, Island County assistant engineer, said Tuesday, adding that crews from the county’s South End road shop had already begun to tackle the problem.
The new hole, estimated to be about 10 feet wide and 10 feet deep, was reported early Sunday evening beneath a two-foot-wide hole in the southbound-lane pavement.
Brackett said “non-destructive” testing of the area after the first hole opened in October had failed to detect the new void near Zimmerman Road.
“Good ol’ science didn’t help us out,” Brackett said.
He said the county had done an interim repair on the first hole, and was in the process of studying how to do a permanent fix this summer, when the new hole appeared.
Brackett said the county will now move forward with a permanent repair, which he estimated would take two to three weeks.
He said the road will remain closed for a few days while the pavement is pealed back and the extent of the problem is revealed.
Brackett expects that one lane of Bob Galbreath Road will reopen soon. Meanwhile, he urged drivers to use Surface Road and other alternate routes.
Brackett said both the sinkholes were caused by the same malfunctioning 2-foot-wide, T-shaped culvert placed about 20 feet below the surface when the road was built about 30 years ago.
He said water was leaching away the sandy fill under the roadway, which had been constructed in a swampy area.
“All that sand isn’t helping us, and the existing conditions when the road was built aren’t helping us, either,” Brackett said.
In October, the first crater was filled with quarry spalls, smaller stone and a cement-style slurry for the last two feet on top. The hole was big enough at the surface that it took about nine yards of the cement mixture to fill.
Brackett said the county had planned to wait until summer, when it’s usually drier, to make permanent repairs, but decided to move ahead on an emergency basis after the new hole appeared.
He said it’s too soon to estimate how much the job will cost.
“It would just be a wild guess at this point,” he said.
“Right now, we’re out to restore the road to a safe condition so it can reopen as soon as possible,” Brackett said.
