HomeMy WebLinkAbout05.23.25 Board Correspondence - FW_ Lake Oroville Community Update - May 23, 2025.ATTENTION: This message originated from outside Butte County. Please exercise judgment before opening
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From:Clerk of the Board
To:Clerk of the Board; Connelly, Bill; Cook, Holly; Cook, Robin; Durfee, Peter; Jessee, Meegan; Kimmelshue, Tod;
Kitts, Melissa; Lee, Lewis; Little, Melissa; Pickett, Andy; Ritter, Tami; Stephens, Brad J.; Sweeney, Kathleen;
Teeter, Doug; Zepeda, Elizabeth; Loeser, Kamie
Cc:Nuzum, Danielle
Subject:Board Correspondence - FW: Lake Oroville Community Update - May 23, 2025
Date:Friday, May 23, 2025 5:02:08 PM
Please see Board Correspondence -
From: California Natural Resources Agency <CNRA@public.govdelivery.com>
Sent: Friday, May 23, 2025 1:26 PM
To: Clerk of the Board <clerkoftheboard@buttecounty.net>
Subject: Lake Oroville Community Update - May 23, 2025
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Lake Oroville Community Update
May 23, 2025
Golden Mussels Found During Boat Inspection at Thermalito
Forebay
The Department of Water Resources’ (DWR) newly implemented invasive mussel
inspection program for State Water Project (SWP) facilities in Oroville uncovered golden
mussels attached to a pontoon boat late Wednesday afternoon in Butte County. Staff
immediately contacted the California Department of Fish and Wildlife (CDFW) for further
inspection and decontamination. The vessel will not be allowed to launch at a DWR
reservoir until CDFW confirms that it is free of mussels.
The pontoon had been out of the Delta waters for an unknown period and was purchased
Wednesday morning in Stockton by Oroville-area residents who planned to launch the
boat at Lake Oroville for the Memorial Day weekend. The boat was brought to DWR’s
inspection site at the North Thermalito Forebay where golden mussels ranging in size
from approximately 1/8 inch to 3/4 inch were discovered during the inspection.
“We are thankful that DWR’s new inspection program in Oroville caught these highly
destructive mussels before they could be introduced to our largest water supply reservoir,”
said John Yarbrough, DWR’s Deputy Director of the State Water Project. “Oroville’s
reservoirs provide water to the Feather River Fish Hatchery and several municipal water
agencies for residential, business, and agricultural use, produce hydroelectric power, and
provide flood control. This discovery further highlights the importance of protecting these
critical functions through watercraft inspections given the ease with which golden mussels
are transported from the Delta.”
More information about the golden mussel discovery is available on DWR’s blog.
Prepare for Water Recreating This Memorial Day Weekend
DWR’s mussel inspection program in Oroville is underway to protect State Water Project
(SWP) infrastructure. Mandatory watercraft inspections are required prior to launching at
the Oroville Facilities (Lake Oroville, Thermalito Forebay, Thermalito Afterbay). DWR’s
free mussel inspections are only performed at the North Thermalito Forebay.
Watercraft that pass the inspection will receive a seal and can launch during designated
ramp hours.
In addition to getting watercraft inspected and sealed for the Memorial Day weekend,
owners should ensure their vessel is in proper working condition prior to launching –
check batteries, filters, and fluids, purchase life vests for all occupants, and remember to
clean, drain, and dry your vessel prior to launching at a new water body.
Watercraft Inspection Location/Decontamination Services
North Thermalito Forebay at Garden Drive and HWY 70 in Oroville
Hours of operation: Daily from 8:30 a.m. to 5:30 p.m.
Watercraft inspections and decontamination services at DWR’s Oroville facilities are free.
To pass an inspection, watercraft must be clean and 100 percent dry.
Vessels that fail inspection can undergo decontamination where water-containing areas
will be flushed with hot (120 F) water to kill mussels and their larvae. Watercraft will then
receive a blue Oroville seal and may launch immediately if desired.
If a boat owner chooses not to have their vessel decontaminated, the vessel can be
sealed with a red quarantine tag and will not be permitted to launch at the Oroville facilities
for a minimum of 30 days. After completing the 30-day quarantine period, the vessel is
eligible for launching.
Sealed Vessel Launching
All trailered and personal watercraft with an intact blue seal and watercraft with a red seal
that have not launched for 30 days will be permitted to launch at the following boat ramp
facilities during the hours listed. Boat ramps at the Oroville facilities will no longer be
open 24/7. Launching trailered boats or personal watercraft is not allowed at any other
location.
When a vessel is leaving the Oroville facilities, staff at designated launch ramps will offer
to re-seal all departing watercraft with a blue Oroville seal. During the next visit, sealed
Oroville vessels can proceed directly to the ramp to launch where a seal checker will
remove the seal. Reinspection is not required as long as the seal is not broken. Re-entry
seals will only be offered to departing vessels during ramp hours. Please plan ahead.
Lake Oroville
Ramp hours: Daily from 7:30 a.m. to 10 p.m.
Lime Saddle
Loafer Point
Spillway
Extended Ramp hours: Daily from 5 a.m. to 10 p.m.
Bidwell Canyon
Thermalito Afterbay
Ramp hours: Daily from 7:30 a.m. to one hour after sunset
Monument Hill
Thermalito Forebay
Ramp Hours: Daily from 7:30 a.m. to 7:30 p.m.
North Forebay (Non-motorized vessels only)
More details about DWR’s mussel inspection program are available at
water.ca.gov/mussels.
Lake Oroville Reaches Full Capacity
Thanks to warming temperatures and ongoing mountain snowmelt in the Feather River
watershed, Lake Oroville reached full capacity this week for the third year in a row,
offering ample water recreation and cooling opportunities for visitors. DWR continues to
monitor Lake Oroville levels to optimize water storage while meeting environmental
requirements and allowing for carryover storage into next year.
With the lake at full capacity, windy periods are likely to cause water to splash onto and
over the crest of the emergency spillway. This will result in minor surface wetting of the
downstream side of the emergency spillway crest and the very upper sections of the
splash pad. Visitors to Oroville Dam may also notice minor amounts of water flowing from
drains built into the emergency spillway. Both conditions are normal and expected given
the emergency spillway design. The dam and emergency spillway continue to operate as
intended.
Temporary Crane Construction Near Diversion Pool
DWR is temporarily constructing a crane along the west side of the Diversion Pool, just
north of the Diversion Dam. The crane and temporary infrastructure will enable the
transfer of two new spherical valves that will be loaded onto barges and transported to
Oroville Dam as part of infrastructure upgrades to the Dam’s River Valve Outlet System
(RVOS). During this operation, Diversion Pool water levels are expected to fluctuate a
couple feet. It is anticipated that the crane and associated work will be completed by the
middle of June.
The RVOS is a series of two parallel outlet conduits, each with two valves, that have the
capacity to draw water from deep in Lake Oroville for release. The RVOS is a critical
feature of the dam, providing the ability to discharge cold water to the Feather River to
maintain water temperatures necessary for fish health. It also ensures the ability to
maintain Feather River flows through RVOS releases during drought years, especially if
reservoir levels drop below Hyatt Powerplant’s water intake structures.
CAL FIRE Burning Grasses Around Thermalito
For the fifth straight year, CAL FIRE Butte County, DWR, and the California Department of
Parks and Recreation (State Parks) will conduct a series of prescribed burns around the
Thermalito Forebay and Afterbay. Prescribed burning began May 23 along north and
south Wilbur Road with additional burns planned for June 9 near the Thermalito Forebay.
DWR’s Thermalito Vegetation Management Project was first conducted in 2021 to
improve valley grassland and vernal pool habitat. Invasive annual grasses and other
invasive species like the yellow starthistle degrade native grasslands and fire is a valuable
tool to combat this degradation. Because invasive species have abundant seeds and dry
material called thatch that build up on the soil, it is important to burn the same area
multiple years in a row. When completed during the right stage in these species' growth
cycle, the prescribed burns eradicate the current crop, reduce the dry residual thatch, and
decrease the spread of seeds. The area has seen a significant decline in the volume of
invasive grasses and starthistles since the project began. The burns also allow DWR to
continue post-fire studies on vernal pool habitat.
Oroville Recreation
Between Jan. 30 and April 20, higher flows in the Feather River required the temporary
removal of sensitive fish monitoring equipment or may have impacted counting operations.
Upstream migrating fish totals through the Feather River Fish Monitoring Station between
Jan. 1 and May 11, 2025 are:
Spring-run Chinook salmon: 3,975
Steelhead: 115
To see previous year data, visit CalFish.org.
Current Lake Operations
Lake Oroville is at 899 feet elevation and storage is approximately 3.41 million acre-feet
(MAF), which is 100 percent of its total capacity and 122 percent of the historical
average.
This email was sent to clerkoftheboard@buttecounty.net from the California Natural Resources Agencyutilizing govDelivery. California Natural Resources Agency, 715 P Street, Sacramento, CA 95814
Feather River flows are at 650 cfs through the City of Oroville with 1,050 cfs being
released from the Thermalito Afterbay River Outlet (Outlet) for a total Feather River
release of 1,700 cfs downstream. Total Feather River releases will increase to 2,500 cfs
on Sunday, May 25. DWR continues to assess Feather River releases daily.
The public can track precipitation, snow, reservoir levels, and more at the California Data
Exchange Center. The Lake Oroville gage station is identified as “ORO.”
All data as of 11:59 p.m. on 5/22/2025.
California Department of Water Resources
715 P Street
Sacramento, CA 95814
Call our general information line at 916-820-8142
or email us at oroville@water.ca.gov
Contact Us
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