SAN FRANCISCO — The cost of repairs and other improvements stemming from last year’s near disaster at the nation’s tallest dam is $1.1 billion, a total nearly $250 million over projections at the start of the year that could go higher, California officials said Wednesday.
Recent additions to crews racing to meet a Nov. 1 deadline to fix spillways at Oroville Dam before winter rains arrive is the primary cause of the increase, the state Department of Water Resources said.
Both spillways at the dam crumbled and fell away during heavy rains in early 2017, prompting fears of a catastrophic dam collapse that forced the evacuation of 200,000 people downstream.
Residents were allowed home a few days later after water behind the dam receded and the danger passed.
Nonetheless, state water officials were left with having to complete a large construction project to make the dam safe.
The department initially awarded a $275 million contract to a private contractor in April 2017 to make the repairs.
Five months later, the cost estimate soared to $500 million and then to $870 million in January.
Unexpected excavation projects have also added to the latest cost increase involving the dam about 160 miles northeast of San Francisco, department spokesman Erin Mellon said.
The water agency plans to ask the Federal Emergency Management Agency to pay for 75 percent of the repair costs after the project is finished. The rest would be borne by State Water Project customers.
FEMA could reject all or portions of reimbursement requests if it determines the crisis was caused by poor maintenance, agency spokeswoman Brandi Richard said.
FEMA has so far contributed $87 million to help with the cost of the $160 million response. Another $45 million is expected.