Lake Oroville Community Update - June 17, 2022


A close-up photo taken near the Basalt Boat Ramp showing part of an algae bloom in the San Luis Reservoir.

A close-up photo taken near the Basalt Boat Ramp showing part of an algae bloom in the San Luis Reservoir.

Water Quality Working Group

In November and December 2020, a multi-agency task force comprised of the State Water Resources Control Board and Central Valley Regional Water Quality Control Board; Butte County Department of Public Works; California Department of Water Resources; California Department of Fish and Wildlife; California Department of Parks and Recreation; and Governor’s Office of Emergency Services came together as the ‘Watershed Working Group’ to address water quality concerns in the North Complex Wildfire burn area and downstream. In 2021, the burn area of the Dixie Wildfire was added for monitoring, and additional partner agencies were added to the working group.

Widespread testing of surface waters throughout these burn scars in Butte and Plumas counties has been completed. Sampling results over the winter of 2021-22 revealed that while contaminant levels were slightly elevated in some instances, they did not exceed primary drinking water contaminant thresholds, and did not adversely impact drinking water treatment facilities or the quality of drinking water they deliver to their communities.

The working group’s agencies will now transition to routine water quality monitoring, which includes monitoring for issues such as Harmful Algal Blooms. Building on the success of the collaboration, this working group will continue to meet to discuss watershed health and be ready for the upcoming fire season. The public is reminded to always treat surface waters before drinking or cooking when recreating outdoors. Homeowners with wells in burn scar areas should review their well construction and consider contacting their county Environmental Health Division for information about testing well water.

Blue Green Algae Monitoring

The Department of Water Resources (DWR) environmental scientists regularly monitor for blue-green algae and their toxins during the  summer months. There are currently no harmful algal bloom (HAB) advisories for Lake Oroville, Upper Feather River lakes, the Thermalito Forebay, or the Thermalito Afterbay. Water samples are taken at various locations regularly from Memorial Day through Labor Day and sent to a lab for toxin analysis.

Blue-green algae (cyanobacteria) is a natural component of ecosystems. Under certain conditions, including warmer temperatures and increased nutrient loads, algae can grow rapidly causing “blooms.” Algal blooms sometimes produce toxins that can be harmful to people and animals. Algal blooms can make the water appear green, blue, or brown in color. Seeing colors, mats, foam, scum, or paint-like streaks in the water may indicate a bloom is present. Keep animals and children away from the water when a suspected HAB is present and report the possible HAB immediately.

If elevated levels of cyanobacteria toxins are found while testing, DWR staff will work with California’s Regional Water Quality Control Board and recreation area managers to notify the public and post advisory signs at affected waterbodies. To learn more about HABs, or to report a HAB visit the Water Board’s website.

Protecting Against Quagga and Zebra Mussels

As boating season kicks off, DWR, California State Parks’ Division of Boating and Waterways (DBW), and California Department of Fish and Wildlife (CDFW) urge boaters to always remember to clean, drain, and dry their boats before entering and leaving lakes, rivers, and other waterways to help prevent the spread of quagga or zebra mussels.

These two non-native freshwater mollusks – quagga and zebra mussels – pose a serious threat to California’s aquatic ecosystems. Quagga and zebra mussels are small, invasive species that colonize on hard surfaces, such as boat hulls and pontoons, docks and pilings, rocks, concrete, plastics, and even discarded bottles and cans. DWR’s Oroville Field Division biologists regularly sample Lake Oroville for indicators the mollusks are present and, to date, none have been found.

Quagga and zebra mussels can be spread to new waterbodies when attached to boats as adults, or as microscopic juveniles in water in motors, bilges, and livewells. They are smaller than a dime, and juvenile mussels may even be difficult to detect with the naked eye. Despite their small size, they can cause major damage to water delivery systems, hydroelectric facilities, and watercraft engines.

When boating, make it a habit to do the following:

  • Remove all plants and animal material from your boat, trailer, and equipment
  • Wash the hull of your boat or other watercraft thoroughly, preferably with high-pressure hot water
  • Clean your gear before entering and leaving the recreation area
  • Drain bilge, ballast, wells, and buckets before you leave the area
  • Inspect all exposed surfaces -- small mussels feel like sandpaper to the touch
  • Dry equipment before launching into another body of water
  • Allow at least a seven to eight day dry-out period before entering another body of water

Report any mussels you find to the local marina and the CDFW hotline at (866) 440-9530.

Oroville Recreation

The Lake Oroville State Recreation Area (LOSRA) is open for boating, camping, hiking, biking, horseback riding, and much more. The four main paved boat ramps at Lime Saddle, Bidwell Canyon, Spillway, and Loafer Point are open, along with the Lime Saddle and Bidwell Canyon marinas, and campground reservations can be made by visiting the California Department of Parks and Recreation (CA Parks) LOSRA website. Restrooms, potable water, and fish cleaning stations are not in service at the Spillway Boat Ramp area but portable toilets are provided – please plan visits accordingly.

The Thermalito Forebays and Afterbay also provide a wide range of water recreation opportunities along with hiking trails, the Clay Pit State Vehicular Recreation area for Off-Highway Vehicles (OHVs) (south of Oroville Airport), and the 11,000 acres of prime wildlife viewing in the Oroville Wildlife Area. The OWA is administered for DWR by CDFW and information about the 11,000-acre Oroville Wildlife Area is available on the CDFW webpage. The Forebay Aquatic Center in the North Forebay Recreation Area is open 10 a.m. to 8 p.m. Friday to Sunday with kayaks, paddle boards, and other watercraft available for rent. The Lake Oroville Visitor Center is open Tuesday through Thursday from 9 a.m. to 5 p.m.

An interactive map of recreation facilities in DWR’s Oroville-Thermalito Complex is available on DWR’s Lake Oroville Recreation webpage. Visitors are encouraged to be fire smart, bring plenty of sunscreen, stay hydrated, avoid leaving valuables in visible areas, be prepared for cold water temperatures, and be mindful of personal safety and the safety of those around you.

Current Lake Operations

The elevation of Oroville’s reservoir is about 766 feet elevation and storage is about 1.83 million acre-feet (MAF), which is 52 percent of its total capacity and 67 percent of historical average. The forecast calls for mid-70s temperatures during the weekend and increasing to the mid-90s to low-100s next week.

The Feather River releases were increased last week and are currently at 3,500 cubic feet per second (cfs) to meet downstream Delta water quality and outflow needs. Currently, flows down the low flow channel through the City of Oroville have been temporarily increased to 1,050 cfs to benefit the spring-run salmon, a threatened species listed under the Endangered Species Act. Flows from the Thermalito Afterbay Outlet have been reduced to 1,450 cfs to maintain total flows at 3,500 cfs downstream of the Outlet. Flows are assessed daily and may fluctuate through the low flow channel for fisheries purposes during the week.

The public can track precipitation, snow, reservoir levels, and more at the California Data Exchange Center at The Lake Oroville gage station is identified as “ORO”.

All data as of midnight 6/16/2022