The L.A. Department of Water and Power said that gusher of a “trunk line” break that caused massive flooding on the UCLA campus cost Angelenos 20 million gallons of perfectly good drinking water.

See also: UCLA Flooded by Tons of Water (PHOTOS)

What's perhaps more amazing than that figure is that the loss only represented about 4 percent of our daily water usage in the city, according to DWP spokesman Joe Ramallo.

One possible reason why Tuesday afternoon's Sunset Boulevard spout was so spectacular and why the flooding was so much worse than any storm has produced for the Westwood campus:

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The break really involved two trunk water lines, not one. According to Ramallo:

 … Two trunk lines that meet at a juncture were involved and both were operating at high pressure.

DWP spokeswoman MaryAnne Pierson told us that both 30-inch trunk lines leading into the Y-juncture cracked. “We also had some problems with valves after they broke,” she said.

The dual nature of the situation is why it has taken so long to get the water under Sunset Boulevard shut off. In fact, the DWP said it still had not been shut off completely. Ramallo explained:

Water flow into the work area has slowed as LADWP water crews carefully work valves in the area to fully close off water to the site of the rupture. Valves are located near the break and along the two trunklines that connect at the point of a “Y” juncture where the break occurred, and connect to Stone Canyon Reservoir. Closing aged valves that operate at high pressure is a complex operation to ensure additional breaks on the lines do not occur.

DWP workers might have to resort to Plan B, an inflatable balloon that can be inserted into a trunk line and filled with air to completely stop the flow of water, the spokesman said.

Credit: DWP

Credit: DWP

That would “allow for removal of the pipe juncture without having to shut down other major water trunk lines serving L.A.’s Westside,” he stated.

The trunk lines were installed in 1921 and is part of the city's aging subterranean infrastructure that will, no doubt, be the topic of debate in City Hall in weeks to come.

UCLA is already saying that damage to the campus — water flooded two parking lots, as well as athletic facilities, offices and Pauley Pavilion — should be covered by L.A. taxpayers. We'd be willing to bet this will end up costing us at least $1 per gallon lost — if we're lucky.

Sunset Boulevard, by the way, will be closed until at least Friday, the department said.

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