Water service was restored in the area Sunday morning, but repairing the sinkhole is taking quite a bit longer. Workers spent Monday filling the hole with dirt then compacting that dirt after that concrete is poured. Once it dries, asphalt will be layered on top and westbound Brannan at 10th will be open to traffic, probably early Tuesday morning.
The 16-inch water main started gushing Saturday afternoon. The San Francisco PUC says the 100-year-old cast iron pipe probably developed tiny cracks over time. Then, colder-than usual water came streaming through the pressurized system on its way down from the Hetch Hetchy Reservoir. The cold water caused the pipe to contract but cast-iron is not flexible, so thoe tiny cracks turned into big ones.
"The top half just popped off, a couple foot section," explained Water Department Division Manager Kevin Barry.
Barry says it does not matter what the temperature is outside the pipe. He says what matters is the water temperature when it begins its journey down from the mountains.
"It's contained in the pipes all the way down, so the temperature drops," Barry told ABC7. "As you know, in the wintertime, you turn on the faucet, your hands get cold. We have the same thing here."
Clean-up continued at the businesses flooded with water and mud. The Thrillpeddlers Theater moved furniture and equipment into the parking lot.
"It's under mud. It's under quite a bit of mud," said Jim Toczyl with the theater. "We're hoping, hopefully we'll be back in business within the next week or two."
At Mountain West, manager Arturo Beyeler filled out a claim form for his damaged merchandise and lost revenues. The repair work is blocking his parking lot and the building entrance at what should be the ski shop's busiest time of year.
"On Saturday, we had a pretty decent day revenue-wise. Then we had this incident happen Saturday night. So, Sunday was probably an 80 percent drop. So, that's the main concern," he said.
There are about 1,200 miles of water pipe in San Francisco. About half of that is cast iron. The city is replacing six miles of pipe per year at a cost of $18 million.
