Cause of water pipeline break in Walnut Creek found

WALNUT CREEK, Calif. (KGO) -- A major aqueduct ruptured and flooded a Walnut Creek neighborhood. Now, three days later, the flow of water has finally turned into a trickle.

The pipeline runs along the Briones-Mt Diablo Regional Trail and it is how the East Bay gets its water. The large pipeline that ruptured delivers 80 million gallons of water a day, so a small leak can cause a lot of damage.

It's the largest pipeline bringing water into the East Bay from East Bay MUD's Sierra Reservoir.

The ruptured aqueduct flooded at least two yards and turned a neighbor's swimming pool into a mud hole. East Bay MUD says it got the emergency call in Walnut Creek Monday morning, but they weren't able to zero in on the leak and stop the flow for two days.

Abby Figueroa from East Bay MUD told ABC7 News, "A pipe like this takes hours to turn off. The valves are very large and it takes a lot of time to stop the water from flowing. If you were to stop it faster, you could cause more breaks up and down the line."

The ruptured pipe is one of three that delivers drinking water from the Sierra reservoirs to the East Bay.

"I felt a jolt on Sunday night around 10:30, plus or minus," Walnut Creek resident Shirley said.

"I felt a sharp jolt. I think it was an earthquake, but I didn't confirm that," Walnut Creek resident Scott Thenell said.

The U.S. Geological Survey says there's no record of seismic activity at the time, which could mean the jolt was caused by the rupture. So far 3.5 million gallons of water has been lost.

"Given the lack of rain and everything else, it's kind of alarming," Walnut Creek resident Griffin Piper said.

Still, it is not a huge impact on the East Bay which uses 160 million gallons each day. On Thursday crews will dig around the pipe, find the leak and begin fixing it. The repair could take a week.