DWR: Final 2017 construction plans for Oroville Dam Spillway approved

Photo courtesy of the Department of Water Resources

OROVILLE, Calif. - The Department of Water Resources (DWR) said Wednesday that they have received authorization to proceed with its final 2017 construction plan from the California Division of Safety of Dams (DSOD) and the Federal Energy Regulatory Commission (FERC).

The work to be completed this year now has all required approvals from federal, state, and independent oversight groups. The independent Board of Consultants (BOC) also approved DWR's construction plans last month pending final approval from FERC.

Officials said the first phase of construction will be completed by November 1, 2017, with the objective of ensuring that the main spillway can safely pass Feather River watershed flows this year. The first phase of construction includes:

Removal and reconstruction of 2,270 feet of the main spillway. Repairs to the uppermost 730-foot portion of the main spillway that connects to the radial gates. This portion will be demolished and reconstructed in 2018. Construction of an underground cutoff wall below the emergency spillway. The purpose of the cutoff wall is to prevent uphill erosion if the emergency spillway is used again.

The remaining construction will be completed in 2018, which will also need federal and state approval, includes:

Addition of structural concrete to the entire main spillway. Resurfacing and hydro-blasting of the energy dissipaters at the base of the spillway. Construction of a roller-compacted concrete buttress (sloped wall) and splashpad on the emergency spillway to dissipate the energy of any waterflows.

The Department of Water Resources' final design and construction plans, which will continue to be monitored by DSOD, FERC, and the independent BOC, include modern technologies and methods to meet and exceed today's safety and construction standards.

The Department of Water Resources said other project-related updates are as follows:

The independent BOC met in Oroville on Monday, July 24 and Tuesday, July 25. The BOC received an overview of DWR's construction schedule and milestones moving forward. The BOC was also be briefed on the design concepts for the 1,050-foot section of the main spillway that will be constructed with roller-compacted concrete in 2017, and an update on foundation preparation and clean-up. The current lake level at Lake Oroville is 800 feet and reservoir releases into the Feather River are now at 6,500 cfs. With guidance from FERC, DWR has established a projection schedule to draw down the reservoir's elevation to 700 feet by November 1. This is a more conservative reservoir level than normal for that date as a public safety precaution. This schedule is tentative and subject to change because of a multitude of contributing factors. DWR this week finished hosting its second round of community meetings to update residents about the Lake Oroville Spillways project. The first meeting was held on Monday, July 17, in Oroville, followed by Wednesday, July 19, in Marysville, and finally Monday, July 24, in Yuba City. These meetings are part of DWR's continued effort to provide updates from DWR leadership and experts on construction efforts, collect feedback from the community and answer questions. The next round of public meetings is planned for late summer or early fall of 2017.
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