Update, noon Monday, quotes from Lafayette city manager.
Engineers, city officials and utility crews on Monday were working at the chasm in Mountain View Drive, Lafayette, to design a series of temporary and permanent fixes.
With the ground saturated by days of rain and water backed up at the culvert that conveys Lafayette Creek under Mountain View, a sinkhole buckled the blacktop on Sunday.
Water and gas service was interrupted to some residences in the lower stretch of the drive a couple of blocks south of Mount Diablo Boulevard, between Crescent Drive and Brook Street.
City Manager Steve Falk, on the scene Monday morning, said engineers and workers are addressing three issues:
- Stabilizing one water line under Mountain View Drive that survived the collapse.
- Forming a plan to restore the culvert carrying the creek past the drive. It might be a temporary culvert to accommodate the next day of rainfall, followed by a permanent culvert, Falk said. Or it might be an expedited job creating a permanent culvert. "I'm giving my engineers that challenge," said Falk, "to design a storm drain that will better address a flood event."
- Begin a plan to replace the road over the creek. That might happen by the spring, Falk suggested.
The total bill for the replacement will be in the six figures, Falk estimated.
A period of heavy rain in 1997 blocked the culvert, forcing the water to flow over Mountain View Drive. But the drive did not collapse then, Falk said.
A trash rack of seven large aluminum tubes was built then to catch debris as it came down Lafayette Creek, which drains western Lafayette. City crews regularly clean debris from that rack, Falk said.
The debris — including limbs, logs and trash — stacked up Sunday before the Mountain View collapse. Still evident on the bank of the stream was a chest of drawers someone apparently dumped in the stream.
Motorists are being detoured around the break in Mountain View Drive. There are some residents who will need to drive a block and a half extra to avoid the severed street, Falk said.
"A handful" of residents remained without water Monday, Falk said. East Bay Municipal Utilities District workers were on the scene.
One customer was without gas Sunday, but it was restored by Monday. That customer happened to be a Lafayette elected (recently re-elected) official, Vice Mayor Mike Anderson, Falk said.
Temporary above-ground lines are conveying EBMUD water and Central Contra Costa Sanitary District sewage lines across the chasm.