Update on Oroville Facilities
Lake Oroville and Oroville Dam in Butte County are part of the State Water Project and an important source of water for Southern California. The Metropolitan Water District is the largest of the state water contractors and imports about 30% of the Southland's water supplies from Northern California.
Oroville's main spillway suffered severe damage in February 2017 when flood control releases from the lake eroded sections of the concrete channel. The subsequent use of an emergency spillway created erosion concerns that prompted an evacuation of communities downstream. Recovery efforts included work on both the main flood control spillway and the emergency spillway to accommodate flows from winter storms.
As of June 27, 2018, DWR crews are continuing foundation cleaning and leveling concrete to prepare for placement of structural concrete walls and slabs. Slab anchor drilling on the middle chute, hydro-blasting of the energy dissipaters at the bottom of the main spillway is complete. Mechanical demolition will continue to prepare for more concrete slab placement. Nov. 1, 2018 is a DWR public safety construction milestone to complete major work and placement of all concrete on the main spillway. Additional work, including dry finishing and curing of concrete, joint sealing, connecting drainage systems, backfilling side walls, and site clean-up on the main spillway will continue after Nov. 1
DWR collaborates with regulatory agencies and a Board of Consultants on the Oroville Spillways design and construction project. Metropolitan has no direct role in the review or implementation of these projects. However, Metropolitan continues to work with DWR on operational issues and future activities at the Oroville facilities in general.
Overview of Oroville Facilities, Regulations and Licensing Process
Media reports have stated that Metropolitan and other state water contractors objected to improvements to Oroville's emergency spillway during a Federal Energy Regulatory Commission (FERC) dam relicensing process due to the potential costs. These reports are erroneous. MWD raised no issues regarding the costs of armoring the emergency spillway.
The State Water Contractors, an association of public water agencies including Metropolitan Water District, has prepared a fact sheet on the Oroville facilities that includes a timeline of recent events, how the facilities are regulated, and background on the licensing process and safety issues.
State Water Contractors fact sheet
No Immediate Impact on Southern California Water Supplies
Water is continuing to be released from Lake Oroville into the river systems that supply the State Water Project. Wet conditions throughout the state are enabling Metropolitan and other water agencies to meet not just current needs, but to replenish reservoirs and groundwater basins.
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