$12.4 Million Contract Awarded to Reinforce Littlerock Dam : Palmdale: Strengthening the structure to better withstand earthquakes is expected to be finished by early ’94. Separate recreational work is to follow.

Directors of the Palmdale Water District awarded a $12.4-million construction contract Monday to strengthen the 69-year-old Littlerock Dam, which does not meet state earthquake standards, and set the stage for a multimillion-dollar improvement of the surrounding recreational area.

The construction contract unanimously approved Monday calls for the dam to be reinforced to better withstand earthquakes and for its height to be raised 12 feet to double its capacity as a reservoir, officials said. That work is expected to take until early 1994 to complete, with the separate recreational work to follow.

“We’re glad to get through everything to where we can start construction of it. It’s been a long hard fight,” said John Sidwell, a water district board member.

Citing earthquake safety, state officials in 1988 ordered Littlerock Dam either reinforced or breached so that it could no longer hold water.

The dam reinforcement, related improvements and various other costs are expected to total about $20.7 million, an amount to be partially offset by a $3-million state grant. The water district this week plans to complete the sale of $16.1 million in certificates of participation to finance most of the work.

District General Manager Hal Fones said the approximately $1.5-million annual debt service on the long-term financing will be paid by developer fees, and from money the water district expects to save by using more dam water and less ground water and aqueduct water, both of which are more costly.

Upon its completion in 1924, the Littlerock Dam was the tallest multiple arch dam in the United States, at about 170 feet in height. Because of its distinctive design, the 700-foot-long structure was placed on the National Register of Historic Places in the 1970s.

Reinforcing the dam against quakes emanating from the San Andreas Fault, about two miles away, will require the arches to be filled in with roller-compacted concrete on the downstream side. As a result, the dam will lose its listing on the historic places register.

The dam collects runoff water from the nearby San Gabriel Mountains and over the years has stored at least one-third of the water used by the Palmdale Water District, which serves central and east Palmdale and surrounding unincorporated areas of the county.

Fones said the upgraded dam will hold about 3,500 acre feet of water, near its original capacity and about double its current reduced capacity of 1,700 acre feet. The capacity has been reduced as silt has accumulated over the years. An acre-foot of water is enough to serve an average family for an entire year.

The dam is actually situated on U.S. Forest Service property so the water district had to obtain federal permits for the work. Consequently, the district was required by the federal government to spend about $1.5 million improving the nearby campgrounds and another $1 million for replanting projects.

The district has already spent about $1.5 million in design and environmental work to prepare for the project, and district officials now expect to spend up to $1 million more for construction management services to oversee the actual strengthening work.

The $12.4-million construction contract was awarded to ASI/RCC Inc. of Buena Vista, Colo., even though a San Diego-based company, Commercial Contractors Inc., had a lower $12.2-million bid. Water district officials said the San Diego firm lacked appropriate experience and submitted a flawed bid.