Now we know what caused that big sinkhole along Interstate 8 last week: an old storm drain installed when Dwight Eisenhower was president.
Caltrans on Wednesday announced plans to fix the 20- by 30-foot sinkhole.
The sinkhole, which caused backups with several lanes closed, was caused by a 42-inch storm drain pipe installed in 1958 that separated from an elbow joint about 40 feet below the freeway.
Caltrans is developing plans that will install a new drain pipe adjacent to the existing one. The work will take place beneath the highway and will require minimal highway lane closures.
“Caltrans crews have stabilized the area where the sinkhole occurred, and we will continually monitor the area until the new system is in place,” said Caltrans Chief Deputy Cory Binns. “We will keep the public informed of the progress as we develop the construction plans.”
Caltrans District 11 maintains more than 10,000 drainage systems, with 18,000 inlets from adjoining properties along the 1,000 center-line miles of highway in San Diego and Imperial counties.