BUREAU PROPOSES QUAKE BOLSTERING AT CASITAS DAM.

Byline: Associated Press 

Casitas Dam needs $20 million in reinforcements to prevent it from failing in a large earthquake and drowning as many as 400 people, federal officials said Wednesday.

A draft report by the Bureau of Reclamation concludes that bolstering the earthen dam with 1.2 million cubic yards of dirt is the cheapest, quickest and most reliable way to do the job.

The report, completed Friday and mailed this week to environmental groups and other interested parties, will be up for public review and comment for 30 days, said bureau spokesman Chris Eacock.

The dam, built in 1959, is about 60 miles northwest of Los Angeles.

``The actual core of the dam is sound'' but the weaker sections could crumble in a quake, Eacock said from Fresno.

The proposed upgrade would strengthen the foundation and the crest of the dam.

``The potential of an earthquake in the area is somewhat high-risk. We feel like we need to move ahead quickly to get a modification in place,'' said Gary Egan, the bureau's regional dam safety officer in Sacramento.

A similar $15 million upgrade is under way at the Bradbury Dam in the Santa Barbara area, he said.

A 1996 study concluded that Casitas Dam was safe for normal operations, Egan said, but an earthquake of magnitude 6.0 or higher could cause liquefaction of portions of the 335-foot-high dam.

``If shaken in an earthquake, it essentially would turn to Jell-O,'' Eacock said.

An earthquake fault lies beneath the dam but it is several miles deep, Egan said.

There is only a 1 percent chance of a major earthquake happening in the area in any given year but that still is a higher risk than authorities like, Egan said.

About 14,000 people living in Casitas Springs, Oak View and west Ventura are in the dam's downstream path.

The federal report said the number of victims would depend on the time and extent of a dam failure. A worst-case scenario could kill more than 400 people.

Most likely, residents would have one or two hours warning, Egan said.

``(Earthquake damage) would cause the dam to start to slump and it would take a while for the water to actually work through cracks in the dam enough to start eroding material out,'' Egan said.

The report noted, however, that any dam failure ``would have a devastating impact to homes, property, utilities and the environment.''

Money for the dam upgrade already is available under a bureau safety program. Unless Congress opposes the plan, work could begin next April. During the 12 to 18 months of construction, the dam's water level might have to be lowered 10 feet, Egan said.

However, it would continue to supply water to more than 50,000 people.