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DWR’s Final 2017 Construction Plans for Lake Oroville Spillways Project Approved

On July 26, 2017 the California Department of Water Resources (DWR) provided an update on construction work on the Lake Oroville Spillways Emergency Recovery Project.

DWR 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) on July 13 and 15 respectively.

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.

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.

DWR’s 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.