Work Begins on Project to Strengthen Casitas Dam

Surveying Coyote Canyon, county disaster planner Jay Bayman imagines the unthinkable: Hundreds of people and entire towns swallowed by mud and water after a big quake collapses the dam that has held back Lake Casitas for 40 years.

“The water would be up there on those hills just like a bathtub ring,” Bayman says, pointing to oak-covered slopes 100 feet above homes on Casitas Vista Road in the valley below. Residents of those homes would be the first casualties in just such a disaster.

To prevent a dam collapse, government officials announced Thursday they have begun work to fortify the dam so it can survive a seismic gut punch to its soft underbelly.

Although work now underway is largely preparatory, the loaders and trucks crawling around the base of the towering dam signal that the heavy lifting required to complete the $42-million project is imminent.

Amid an atmosphere of both dread and reassurance, government officials gathered atop the dam Thursday to hail the project and brief news media on the progress to date. Behind them, boats glided over serene blue waters and shadows chased across the distant Santa Ynez Mountains. Below unfolded the canyon that could shoot flood waters into Casitas Springs and downtown Ventura if a magnitude 6.5 quake, the worst-case scenario, strikes near the dam.

Dignitaries, including Rep. Elton Gallegly (R-Simi Valley) and Ventura Councilman Sandy Smith, turned ceremonial shovels of dirt, cracked jokes and smiled for a TV camera.

“We don’t want to send a message the sky is falling,” Gallegly said. “It would take a tremendous hit for this dam to fail.”

Nearby, Bayman with the county Office of Emergency Services pondered what might happen if a large quake should strike before the work is complete.

“Goodness gracious, look at where all that water would go. It’s my job to visualize disaster,” he said.

Engineer Barry Longwell oversees the fortification project for the U.S. Bureau of Reclamation, which owns Casitas Dam. He said the dam is sound now and will only get stronger as work progresses.

One of the first tasks was to install a flood siren at the construction site. Two more were erected Thursday, one at Foster Park and the other in Casitas Springs. Five more are to be installed along the Ventura River to the Pacific, probably by the end of the month, officials say.

The bureau, stung by criticism it has not adequately informed the community about the project, has established an information hotline--(805) 641-9494--launched a Casitas Dam newsletter and held public workshops.

When children return to classes at west Ventura schools next month, for instance, they will be welcomed by “Ready Freddy,” a docile black Labrador retriever, and his handler, who will show children how to flee low-lying buildings if the sirens sound.

“He’s a search dog. He looks for people who are buried alive,” said Debra Tosch of the Natural Disaster Search Dog Foundation.

Under the dam enhancement project, a dozen wells now being installed at the base of the dam will remove water that makes soil unstable. A million tons of dirt will be excavated, compacted and replaced to solidify the base of the dam. Tons of earth will be piled along the dam, more than doubling its breadth, to bulk up its downstream face.

“It’s like we are building another dam on top of this one,” Longwell said. The objective is to complete those tasks by mid-December, before seasonal rains come, he added.

Next year, work crews will spend about eight months building an earthen berm on about 10 acres at the base of the dam. It will function much like a chair propped against a doorknob, providing enough resistance to keep the downstream half of the dam upright should strong shaking from a quake collapse the portion facing the water, Longwell said.

“Our goal is to prevent a catastrophic failure” and not make the dam impervious to quake damage, he said.

The lake will not be lowered during construction. Work is scheduled to be completed by August 2000. The work is being done by Montana-based Barnard Construction Co.

A survey of western dams conducted by the bureau in 1994 and 1995 revealed Casitas Dam was more vulnerable to strong ground motion and liquefaction, a condition where soil behaves like pudding, than previously believed.

A dam collapse could kill 400 people, displace 14,000 residents, mostly in Ventura, and cause $350 million in property damage, according to estimates prepared by the bureau.

“It’s a worst-case scenario, but we have to be prepared for it,” Bayman said.