Bureau of Reclamation, California.
O'Neill Dam and Forebay are joint Federal-State facilities located on San Luis Creek 2.5 miles downstream from San Luis Dam. O'Neill Forebay Dam is a feature of the Central Valley Project - San Joaquin Division - San Luis Unit. The reservoir has a surface area of 2,250 acres and 14 miles of shoreline. The Park includes boating, camping, picnic facilities, fishing, hiking, and serves as a major family destination for many in the west central valley. Currently an expansion of the Maderos boat ramp facilities is underway, which will improve boat access and day use facilities.
Effective immediately, Reclamation will require all boats launching at Lake Berryessa to participate in a seal program to prevent the spread of invasive mussels. All vessels wishing to launch at Lake Berryessa will be inspected. A red quarantine seal will be applied for 30 days during, which the vessel will not be permitted to launch. Vessels that have finished the 30-day quarantine may return to the lake and have the seal removed by authorized staff and will be allowed to launch. For more information on this updated protocol, please view the press release here: https://www.usbr.gov/newsroom/news-release/5031.
The site is located about 10 miles west of Los Banos, California on CA Highway 152.