Thursday October 1, 2026
CDWR —
The California Department of Water Resources (DWR) announced today the completion of a $235 million project to rehabilitate Oroville Dam’s river valve outlet system (RVOS), ensuring the continued operation of a critical feature of the dam for decades to come. This upgrade improves operational reliability, protects fish populations, and strengthens the State Water Project’s resilience to climate-driven extreme heat and drought.
Oroville Dam, the tallest dam in the United States at 770 feet, is a cornerstone of the State Water Project, providing flood protection to downstream communities, water supply, clean energy generation, and recreation while supporting Feather River habitat for endangered and threatened fish species. Constructed between 1961 and 1967, the earthen dam towers over the northern Sacramento Valley.
The RVOS is located deep within one of the dam’s early diversion tunnels and allows DWR to release cold water from the deeper portions of Lake Oroville into the Feather River. That capability is especially important during periods of extreme heat and drought, when colder releases can help reduce downstream water temperatures and support fish populations.