ORINDA -- The cost of repairing a large sinkhole that formed last year during an intense rainstorm has taken Orinda leaders by surprise, but the city is moving ahead with the fix.
Originally assessed by an engineering consultant as a $467,455 job, the Tarabrook storm drain repair will now cost the city more than $1.2 million after the project failed to attract more bids. On Aug. 5, a City Council majority approved a construction contract with Novato-based Bay Pacific Pipelines, Inc. whose bid was about $421,400 less than one proposed by Pfister Excavating, Inc. of Vallejo.
The fix includes replacing a section of metal drainage pipe that sits more than 25 feet below the street. That pipe failed sometime during a Dec. 1-2 storm. Since then, city crews have been diverting water around the blocked pipe with rented pumps. A damaged sewer line has also been repaired.
According to a city report, the repair plans call for crews to place a new 36-inch reinforced concrete pipe using a more affordable "jacking and boring" method to reduce surface disturbance. Pavement repair, grading and some landscaping is planned.
The city has obtained construction and other easements from neighbors living near the site. It is also in the process of getting permits from state and regional agencies for the project designed by Pleasant Hill-based Harrison Engineering Inc. That firm was hired by the city in January following an approval of a $99,000 contract.
In a letter to the city, the firm explained that the disparity between the consulting engineer's estimate of the construction cost and the actual bids was possibly due to timing bid requests during the peak work season and a revitalized construction market.
"This project was bid at the worst possible time due to current contractor demand and the tight project schedule," project engineer Randell T. Harrison wrote. "The review of the contractors' bids seems to indicate that the bidders recognized these factors and submitted elevated bids for work."
City leaders had transferred $636,564 from the general fund to the capital improvement project budget for the repair. They are now using $500,000 set aside in the 2014 operating budget for slope stabilization and road repairs resulting from landslides to cover the more than $915,200 difference.
Mayor Amy Worth, Councilwoman Victoria Smith and Councilman Dean Orr expressed frustration over the repair costs. But citing possible future bad weather and an increasingly busy construction market, among other issues, they agreed the proposed fix should go forward.
"There's nothing that makes us happy about spending a lot more money than we expected," said Smith. "The economy is getting better and everybody's going out to do work and it's probably going to get worse and not better."
Councilman Steve Glazer voted against the fix, saying he did not support using money from the slope stabilization fund.
"I would rather take the time to get a better bid climate to make sure we do a good job in the winter of mitigating the rains," Glazer said.
The expense will nearly exhaust the stabilization fund's balance, which took a hit last year due to emergency repair work at the Tarabrook site. City leaders -- who augmented the fund recently as part of the two-year budget process -- will likely replenish the fund with general fund money during the one-year budget adjustment, said Public Works Director Charles Swanson.
The city also expects to receive $250,000 in insurance funds to help pay for the work, which is scheduled to begin in September and wrap up in about 60 days.