Littlerock Dam Is Stronger, but Plainer : Littlerock: Edifice loses its architectural character to a project to increase its safety.

Littlerock Dam, a 69-year-old Antelope Valley landmark, is midway through a massive make-over that will help it hold more water and better withstand an earthquake, but the changes will obscure the structure’s architectural significance.

Construction crews are building concrete steps that will soon cover and reinforce the distinctive arches on the dam’s downstream side. Then the workers will raise the height of the dam by 12 feet to boost its storage capacity.

The changes have bumped the structure off the National Register of Historic Places.

Nevertheless, directors of the Palmdale Water District, the dam’s co-owner, are pleased that the $22-million project will mark the end of a 63-year-old dispute with state officials, who have questioned the safety of the structure.

“I’ve been excited since the day they broke ground,” said John Sidwell, a district board member. “It was a long, hard-fought battle to go through.”

Although the dam area has been closed to the public since July, an open house was held last week to let residents view the renovation work and get a last glimpse of the dam’s downstream arches before they are obscured by new concrete.

The 170-foot-tall dam was opened in 1924 to control flooding and provide a source of water for farmers by capturing runoff from the nearby San Gabriel Mountains. But state dam inspectors began to question its durability as far back as 1930.

“They became concerned about the cracks that were found in the dam,” said Charles Keene, an environmental specialist with the state Department of Water Resources. “They were also concerned about the proximity of the dam to the San Andreas Fault.”

If a major earthquake occurred along the fault line, just two miles from the dam, state officials feared the structure would not hold up.

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During the next 50 years, the dam’s owners made minor changes and hired consultants to propose more ambitious reinforcement plans. Meanwhile, state regulators limited the amount of water that could be stored behind the dam.

The dam’s owners, the Palmdale Water District and the Littlerock Creek Irrigation District, lacked the funds for a major upgrade and kept the state at bay by conducting countless studies and filing a lawsuit, Keene said.

Old-timers in the Antelope Valley fought to preserve the dam, saying it has held up fine for decades, despite several earthquakes.

But ultimately, state officials gave the owners two choices--either strengthen the dam or breach it so it could no longer hold water.

“In 1988, the districts decided to say we’re sick of fighting,” Sidwell said.

That year, the renovation of the dam was estimated to cost $8 million, to be paid by district funds and a $3-million state grant.

But the costs have ballooned since then, partly because of rigorous state and federal reviews and the need to mitigate environmental damage to the surrounding national forest.

“For every acre we’ve destroyed here, we’re planting three acres upstream,” said David Myers, business manager for the water district.

Also boosting the cost were requirements to provide better recreational facilities, such as parking lots, restrooms, picnic areas and a boat launch.

The water district, which serves central and east Palmdale, plus some unincorporated areas, is shouldering most of the costs through the sale of certificates of participation and developer fees. In addition, the district expects to save money by using more dam water, which costs less than well water or aqueduct supplies.

To make the dam strong enough to hold more water--and stand up during an earthquake--construction workers are using roller-compacted concrete for the new wall on the downstream side.

“We’re building a new dam that grabs ahold of (the old dam’s) buttresses, so they won’t be able to move any more in an earthquake,” said Chris Weddle, an engineer who is overseeing the project.

The reinforcement and raising of the dam’s height are expected to be completed in April. But the dam area, which attracts about 300,000 visitors annually, will not be reopened to the public until the recreation improvements are finished, perhaps in another year.

Keene of the state Department of Water Resources said his agency still believes Littlerock Dam, so close to an earthquake fault, is poorly located. Nevertheless, he said state officials are pleased to see it reinforced at long last.

“We’re happy it was a win-win situation,” he said. “The dam will not be torn down or breached, and the residents will benefit from it. Down the road, it’s going to look like a pretty good investment for securing water for the Antelope Valley.”