The California Department of Water Resources announced Friday that the cost of last year's Oroville Dam spillway failure and ongoing reconstruction effort has grown to $870 million, a tab that the state continues to hope is paid largely by federal taxpayers.
That new cost estimate includes $210 million in previously untabulated project costs and represents a 30 percent jump from an estimate released last fall.
DWR also said Friday that several of the new concrete slabs placed as part of the spillway project may need "corrective action" because of "surface imperfections" that arose because of problems that occurred during the 2017 construction season.
In a construction update briefing, DWR spokeswoman Erin Mellon said that the revised $870 million figure includes:
- $500 million for rebuilding the shattered main concrete spillway and efforts to reinforce the adjacent hillside that serves as an emergency spillway. The original estimate for the work, being performed by Kiewit Infrastructure West, was $275 million.
- $210 million for related work, including removing debris and sediment from the Feather River, replacing power lines, building access roads, payments to consultants and staff time. Friday's report was the first explicit statement of these related recovery costs. Mellon said she could not offer a breakdown of the specific costs that added up to the $210 million figure.
- $160 million for the emergency response during and for two months after the main spillway failure and subsequent severe erosion of the emergency spillway that led to evacuation orders for 188,000 people downstream of Oroville Dam. DWR had announced this subtotal last year and noted it was substantially less than earlier estimates.
Mellon said DWR has reported the $870 million estimate to the Federal Emergency Management Agency, which reimburses up to 75 percent of the costs of federal emergencies. So far, FEMA has reimbursed DWR $86.9 million, or exactly 75 percent, of the first $115.9 million in detailed costs the department has submitted.
DWR says that costs not covered by FEMA will be paid by the State Water Contractors. That's the group of 27 urban and agricultural water agencies that get water from the State Water Project, of which Oroville Dam is the key facility.
Mellon said Friday the spillway-related costs may continue to "evolve," based on changing conditions or new requirements for the massive project. Work on the main spillway is about half complete, and Kiewit's crews are focusing during the winter months on a massive concrete-pile wall on the slope of the badly eroded emergency spillway. The contractor is also preparing to place a 22-acre "splash pad" on the slope immediately below the massive concrete weir at the very top of the emergency spillway hillside.
One of those unforeseen costs this year could be the potential "corrective action" that DWR says may be needed on three of the 234 concrete spillway slabs placed during the 2017 construction season.
Ted Craddock, a DWR deputy director who has been put in charge of the Oroville reconstruction project, said in a statement he read during the media call that the concrete in the three slabs "did not cure as anticipated." Craddock said the curing problem grew out of an unscheduled outage of a batching plant at the construction site that prevented crews from placing the concrete within the required time and "hot, high winds (that) dried the surface of the slabs before the contractor could finish final surfacing work."
Mellon said in a follow-up email that DWR is consulting with Kiewit and regulators to decide "if remediation is necessary and what that work would include."
Cracking in many of the 234 newly placed concrete slabs came to light last fall when the Federal Energy Regulatory Commission, which oversees the Oroville facilities, asked DWR to explain the cracks and what it planned to do about them.
The department maintained that the cracks "are something you expect to see" and were due largely to reinforcement steel, anchor bars and other design elements that strengthen the slabs but exert stress as the concrete cures.