Empty reservoir awaits cover

June Casagrande

The Big Canyon Reservoir, which normally supplies most of the water

used in the city, is now empty, and workers have begun making

preparations for a plastic cover to be installed next year.

City officials have been trying for years to get a cover for the

city reservoir to protect local water supplies from everything from

terrorist attacks to midge fly larvae infestation. The $5-million

project will be paid for in part with $875,000 from the federal

government. City leaders will find out in a few weeks whether

Washington will bankroll up to $1.5 million more of the cost.

“We’re moving ahead either way,” Assistant City Manager Dave Kiff

said.

Two smaller city reservoirs off 16th Street are being used to

store some city water supplies while the larger reservoir is being

cleaned, repaired and upgraded and while environmental tests are

underway. The city will continue to get most of its water from the

Orange County Water District’s underground aquifer, supplemented by

imports from the Metropolitan Water District.

“We hope that work on the reservoir cover will start in late

January or early February and that the reservoir will be completed

nine months after that,” City Manager Homer Bludau said.

The $5 million to cover the reservoir includes $1 million for a

circulation system that will prevent the enclosed water from

stagnating. The cost also covers landscaping and adding trees around

the reservoir to soften neighbors’ view of the black plastic cover.

Water in covered reservoirs undergoes a different treatment

process from water in open reservoirs. Instead of using chlorine gas,

a combination of liquid chlorine and ammonia will treat water there

in the future, which brings a perk, Kiff said.

“Chlorine gas, which is highly volatile, is no longer being stored

there,” Kiff said. “Having chlorine gas there was a fairly big risk

in case of a gas leak and was one of our highest areas of concern for

a terrorist attack or other mishap.”