Grebes Nest Receive Help from DWR
Western and Clark’s grebes, with their distinctive red eyes, graceful necks, and long yellow bills, have returned to the Thermalito Afterbay for their nesting season. The shallow nature of the Afterbay is perfect for these two species of grebes who, along with only a few other aquatic bird species, build their nests on the water’s surface. Reservoirs like Thermalito Afterbay support more than 90 percent of the state’s breeding-grebe population, according to the Audubon Society.
DWR voluntarily restricts fluctuating the elevation of the Thermalito Afterbay for several weeks during the grebes nesting season because significant decreases in reservoir elevation could strand the nests out of the water or submerge them if elevations increase. Find more information about the grebes on the DWR Updates webpage. Photos can be found on DWR’s Pixel webpage – enter Grebes in the search bar after creating a free username and password to log in.
Fish Advisory for Antelope Lake
The California Office of Environmental Health Hazard Assessment (OEHHA) released an advisory for safe eating advice for black bass species, bullhead species, Golden Shiner, and sunfish species caught at Antelope Lake in Plumas County due to levels of mercury found in fish caught from the lake. The fish species tested at Antelope Lake had lower contaminant levels than is typical at many other California water bodies. All species tested at Antelope Lake can be eaten at least two times a week.
Mercury is released into the environment from mining and burning coal. It accumulates in fish in the form of methylmercury, which can damage the brain and nervous system, especially in developing children and fetuses. Because of this, OEHHA provides recommendations for safe eating that vary by age and gender. More information can be found in the OEHHA news release.
Oroville Recreation and Boat Ramp Update
The boat ramp at Lime Saddle recreation area will be closing Monday, August 29 as lake elevations fall below safe launching levels. The Lime Saddle Marina will remain open.
The Bidwell Canyon, Spillway, and Loafer Point boat ramps remain open, along with the Lime Saddle and Bidwell Canyon marinas. Reservations for campgrounds in the Lake Oroville State Recreation Area (LOSRA) can be made by visiting the California Department of Parks and Recreation (CA Parks) LOSRA website.
The Lake Oroville area has over 92 miles of trails, open to hiking, with some also allowing for horseback riding, some also allowing biking, and some designated for “multi-use” where all three activities may occur on the same trail. The trails provide users with spectacular views of Lake Oroville and the valley, home to the Sutter Buttes – named the smallest mountain range in the world.
Trails and their permitted uses, day use areas, boat ramps and other recreation facilities are featured on DWR’s interactive map on DWR’s Lake Oroville Recreation webpage. Step inside the Lake Oroville Visitor Center, open Tuesday through Thursday from 9 a.m. to 5 p.m., to learn about the State Water Project and history of the area.
The Thermalito Forebay and Afterbay also provide a wide range of recreation opportunities including fishing, hiking, biking and boating. Non-motorized boating is permitted in the North Forebay, and motorized boating is permitted in the South Forebay and Afterbay. The North Forebay Aquatic Center has kayaks, paddle boards, and other watercraft available for rent. Non-motorized boating is also permitted in the Thermalito Diversion Pool with car-top boat launching access just before the restroom on Cherokee Road. Lake Oroville and the Oroville Wildlife Area also have car-top boat launch areas.
Tracking Dove Populations
Staff from the California Department of Fish and Wildlife (CDFW), along with assistance from California Department of Water Resources (DWR) staff, have been in the Oroville Wildlife Area (OWA) since July 11 to collect information on the local mourning dove population. Working in the safflower and sunflower fields in the OWA, that were planted by CDFW staff to provide a readily available food source for doves and many other bird species, staff successfully captured and placed identifying bands on 33 doves.
Mourning doves are an important migratory game bird and California is one of 39 states participating in a national effort to monitor the mourning dove population to better estimate annual survival and guide harvest-management decisions. CDFW and DWR staff record the sex and approximate age of each banded bird and place a metal band with a unique identification number and a toll-free phone number to report the band around the dove’s leg.
The hunter is the critical link in the dove banding study. Their reporting of the dove’s leg band enables wildlife managers to understand the effects of annual hunting regulations on mourning dove populations and allows for greater understanding of their migratory patterns. The Oroville Wildlife Area is a popular hunting location and CDFW expects 80 to 100 opening day hunters when Dove season opens on Sept. 1.
For more information on CDFW activities in the OWA to increase forage for local and migratory birds, visit the DWR Updates webpage and search ‘sunflower’ to access the digital article and previous stories in the Lake Oroville Community Update newsletter.
Chinook Salmon Return to the Feather River
Chinook salmon are completing their life cycle and returning home to the Feather River to lay eggs for the next generation of salmon. The Feather River Fish Hatchery plans to open the fish ladder the week of Sept. 12 to begin hatchery spawning operations which enables millions of Chinook salmon to be released to the river every spring.
Visitors to the Hatchery’s Fish Barrier Dam Overlook Viewing Area can watch salmon jumping and after the fish ladder opens in mid-September, visitors can watch salmon swim up the ladder at the Underwater Viewing window. The Overlook is located off Table Mountain Boulevard north of the Hatchery. Visitors are also encouraged to visit the Hatchery (open daily 8 a.m. to 3 p.m.) and attend the 28th Annual Salmon Festival in Oroville on Sept. 24.
Blue Green Algae Monitoring
DWR environmental scientists regularly monitor Lake Oroville, the Thermalito North Forebay, and the Thermalito Afterbay for blue-green algae and their toxins, taking water samples from various locations regularly from Memorial Day through Labor Day. There are currently no harmful algal bloom (HAB) advisories for Lake Oroville, the Thermalito Forebay, or the Thermalito Afterbay.
If elevated levels of cyanobacteria toxins are found, DWR staff 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.
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.
Visit this comparison chart on the HABs website for additional information.
Current Lake Operations
The elevation of Oroville’s reservoir is about 709 feet elevation and storage is about 1.32 million acre-feet (MAF), which is 38 percent of its total capacity and 63 percent of historical average. Temperatures are forecasted to be in the low 90s through the weekend and increasing to the upper 90s and low 100s next week.
The Feather River releases are currently at 3,000 cubic feet per second (cfs) to meet downstream Delta water quality and outflow needs. Flows through the City of Oroville are 1,000 cfs with 2,000 cfs released from the Thermalito Afterbay Outlet (Outlet) for a total of 3,000 cfs downstream of the Outlet. Flows through the low flow channel may be reduced next week for fisheries purposes.
The public can track precipitation, snow, reservoir levels, and more at the California Data Exchange Center at www.cdec.water.ca.gov. The Lake Oroville gage station is identified as “ORO”.
All data as of midnight 8/25/2022