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HomeMy WebLinkAbout06.04.26 Board Correspondence - FW_ Project Operations Compliance Report submitted in FERC P-803-000 by Pacific Gas and Electric CompanyFrom:Clerk of the Board To:Clerk of the Board; Connelly, Bill; Cook, Holly; Cook, Robin; Durfee, Peter; Jessee, Meegan; Kimmelshue, Tod; Kitts, Melissa; Krater, Sharleen; Lee, Lewis; Little, Melissa; Pickett, Andy; Ritter, Tami; Stephens, Brad J.; Sweeney, Kathleen; Teeter, Doug; Zepeda, Elizabeth Cc:Loeser, Kamie; Cannon, Jamie Subject:Board Correspondence - FW: Project Operations Compliance Report submitted in FERC P-803-000 by Pacific Gas and Electric Company Date:Thursday, June 4, 2026 1:46:29 PM Please see Board Correspondence - Lewis Lee Administrative Technician - Confidential Butte County Administration 25 County Center Drive, Suite 200 • Oroville, CA 95965 T: 530.552.3326 www.buttecounty.ca.gov | lelee@buttecounty.ca.gov -----Original Message----- From: 'FERC eSubscription' <eSubscription@ferc.gov> Sent: Thursday, June 4, 2026 1:36 PM Subject: Project Operations Compliance Report submitted in FERC P-803-000 by Pacific Gas and Electric Company .ATTENTION: This message originated from outside Butte County. Please exercise judgment before opening attachments, clicking on links, or replying.. On 6/4/2026, the following Filing was submitted to the Federal Energy Regulatory Commission (FERC), Washington D.C.: Filer: Pacific Gas and Electric Company Docket(s): P-803-000 Lead Applicant: Pacific Gas and Electric Company Filing Type: Project Operations Compliance Report Description: Pacific Gas and Electric Company submits 2026 Operations and Maintenance Plan re the DeSabla-Centerville Hydroelectric Project under P-803. 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Box 28209 Oakland, CA 94604 June 4, 2026 Via Electronic Submittal (E-File) Debbie-Anne Reese, Secretary Federal Energy Regulatory Commission 888 First Street, NE Washington, D.C. 20426 RE: DeSabla-Centerville Hydroelectric Project, FERC No. 803-CA 2026 Operations and Maintenance Plan Dear Secretary Reese: Pursuant to the Federal Energy Regulatory Commission's (FERC) Order Amending Temperature Requirements1 (Order) issued on August 20, 1998, Pacific Gas and Electric Company (PG&E) is submitting its 2026 Operations and Maintenance Plan (2026 O&M Plan) for the DeSabla- Centerville Hydroelectric Project, FERC No. 803 (Project). Consistent with FERC's Order, PG&E held a meeting to discuss the 2026 O&M Plan on April 29, 2026, with the National Marine Fisheries Service, California Department of Fish and Wildlife, the U.S. Fish and Wildlife Service, and the United States Forest Service. The draft 2026 O&M Plan was provided to the Resource Agencies via email on April 28, 2026. The 2026 O&M Plan addresses the coordinated operation of the Project and continues to support a water temperature monitoring and forecasting approach to detect changing summer weather conditions in a timely manner. (Enclosure 1) contains the clean final version of the 2026 O&M Plan. Agency comments on the draft version of the 2026 O&M Plan and related correspondence are provided with this filing as (Enclosure 2). (Enclosure 3) contains the edited, redlined, version of the 2026 O&M Plan. Should you have any questions or comments, please do not hesitate to contact PG&E’s license coordinator, Duncan Drummond at 530-215-9678. Sincerely, Matthew Joseph Supervisor, Hydro License Compliance Enclosures: 1. Clean Version of 2026 DeSabla Centerville Operations and Maintenance Plan 2. Agency Comments and Correspondence 3. Draft Redlined Version of 2026 DeSabla Centerville Operations and Maintenance Plan cc: See Attached List 1 August 20, 1998, Oder Amending Temperature Requirements FERC Accession Number 19980824-0335 Debbie-Anne Reece, Secretary June 4, 2026 Page 2 cc: via email w/enclosures Tracy McReynolds (CDFW) – Tracy.McReynolds@wildlife.ca.gov Grant Henley (CDFW)- Grantton.Henley@wildlife.ca.gov Anna Allison (CDFW) – Anna.allison@wildlife.ca.gov Beth Lawson (CDFW) – Beth.Lawson@wildlife.ca.gov Ellen Roots (NOAA Fisheries) – ellen.roots@noaa.gov Cathy Marcinkevage (NOAA Fisheries) – cathy.marcinkevage@noaa.gov Yvette Redler-Medina (NOAA Fisheries) yvette.redler-medina@noaa.gov Victor Orozco (USFS) - victor.aguirreorozco@usda.gov Kurt Sable (USFS) – kurt.sable@usda.gov Stephanie Millsap (USFWS) - Stephanie_Millsap@fws.gov Brittany Reaves (USFWS) - brittany_reaves@fws.gov65 Eric Bradbury (SWRCB) – Eric.Bradbury@waterboards.ca.gov ENCLOSURE 1 PACIFIC GAS AND ELECTRIC COMPANY DeSabla-Centerville Hydroelectric Project FERC No. 803 2026 OPERATIONS AND MAINTENANCE PLAN Prepared By: May 2026 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan TABLE OF CONTENTS 1.0 Introduction ............................................................................................................................ 3 1.1 Project Features .............................................................................................................. 3 1.2 Project Benefits to Butte Creek Habitat .......................................................................... 4 1.3 Background ..................................................................................................................... 4 1.3.1 The Resource Group.................................................................................... 4 1.3.2 Project Reservoirs ....................................................................................... 5 2.0 WATER YEAR TYPE AND OPERATIONS ................................................................. 8 2.1 Water Year Type for 2026 .............................................................................................. 8 2.2 Reservoir Operations for 2026 ........................................................................................ 8 2.3 Lower Centerville Canal Operations for 2026 .............................................................. 11 2.4 2026 Minimum Instream Flow Temporary Amendment .............................................. 11 2.5 Contingency for Extreme Heat Event During the Holding Period ............................... 12 2.6 Spawning Flows in Butte Creek ................................................................................... 14 2.7 Scheduled and Emergency Maintenance and Operations ............................................. 14 3.0 WATER QUALITY MONITORING ........................................................................... 16 4.0 CONSULTATION .......................................................................................................... 17 5.0 REFERENCES ................................................................................................................ 19 TABLE OF EXHIBITS Exhibit A. Map of Project Area .................................................................................................... 19 Exhibit B. Comparison of Philbrook Reservoir Storage Usage .................................................... 20 Exhibit C. Historical Runoff Forecast and Water Year Type Since 1998 .................................... 21 Exhibit D. 2026 and 2027 Projected Scheduled Maintenance and Outages ................................. 22 Exhibit E. 2026 PG&E Seasonal Monitoring locations ................................................................ 23 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 3 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 1.0 INTRODUCTION The Operations and Maintenance Plan’s (O&M Plan) objective is to manage flows from the DeSabla-Centerville Hydroelectric Project (Project) reservoirs to support holding, spawning, and rearing Central Valley spring-run Chinook salmon (Oncorhynchus tshawytscha; CVSRCS) use in the reaches of Butte Creek below the DeSabla Powerhouse during 2026. It also documents Pacific Gas and Electric Company’s (PG&E) scheduled outages that allow for the Project maintenance activities. In addition, this O&M Plan outlines the procedures and practices PG&E will strive to follow in the operation of the Project to enhance and protect habitat for CVSRCS. Finally, this O&M Plan provides the basis for modification of the reservoir temperature release criteria established in the Federal Energy Regulatory Commission (FERC) “Order Approving Water Temperature Study Report” issued August 21, 1997, as amended by FERC’s “Order Amending Temperature Requirements” issued August 20, 1998. 1.1 Project Features The DeSabla – Centerville Hydroelectric Project includes the following features which are depicted on the project map which is included with this O&M Plan as Exhibit A: Reservoirs and Forebays:  Round Valley Reservoir (also known as Snag Lake)  Philbrook Reservoir  DeSabla Forebay Canals and related features:  Butte Canal (out of service since 2023)  Hendricks Canal  Toadtown Canal  Upper Centerville Canal  Lower Centerville Canal (LCC; out of service since 2014)  associated diversion dams, feeders, and spillway channels DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 4 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Powerhouses:  Toadtown Powerhouse  DeSabla Powerhouse  Centerville Powerhouses (CVPH) 1.2 Project Benefits to Butte Creek Habitat Water diverted from the West Branch Feather River (WBFR) at the Hendricks Head Dam (HDD); and releases from Philbrook and Round Valley Reservoirs can increase the total flow available in Butte Creek below DeSabla Powerhouse by up to approximately 40% in July and August (depending on water availability in Butte Creek). Water imported from the WBFR provides additional water to moderate water temperatures in reaches of Butte Creek used by CVSRCS for over-summering by providing releases from Philbrook Reservoir when storage is available. The increased flow from the Philbrook Reservoir releases help minimize heating by decreasing travel time in the Hendricks Canal and by reducing the residence time in the DeSabla Forebay. 1.3 Background 1.3.1 The Resource Group On August 21, 1997, the FERC issued an Order placing temperature restrictions (17º C at Round Valley and 18º C at Philbrook) on the water releases from these dams. On August 20, 1998, and 2020-2021, the FERC revised its Order to allow for modification of the criteria upon mutual agreement of the National Marine Fisheries Service (NMFS), the California Department of Fish and Wildlife (CDFW), and the United States Fish and Wildlife Service (USFWS); PG&E has also included the State Water Resource Control Board (SWRCB), and United States Forest Service (USFS) in this consultation process. These five agencies are referred to as the Resource Agencies in this Plan. Since 1999, this agreement has been accomplished by way of an annual O&M Plan. Reservoir operation has been based on expected water year conditions. Pursuant to FERC’s August 21, 1998, Order, this O&M Plan is annually updated and modified as appropriate in consultation with the Resources Agencies. This consultation group, composed of PG&E and the Resource DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 5 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Agencies, is called the Resource Group in the remainder of this Plan. Starting in 2016, a schedule of annual maintenance outages of the DeSabla-Centerville Canals was included in this O&M Plan. 1.3.2 Project Reservoirs The Project storage reservoirs (Round Valley and Philbrook Reservoirs) are in the WBFR watershed. Project diversions are made from this drainage at the HDD. Due to the larger maximum storage capacity and depth of Philbrook Reservoir (5,000 acre-feet) relative to Round Valley Reservoir (1,200 acre-feet), the water temperature tends to stay cooler for a longer period in Philbrook Reservoir. Round Valley Reservoir Since 1998 PG&E has released water from Round Valley Reservoir first, to effectively manage the temperature of water released into Butte Creek. During initial management of the Reservoirs there was concern that releases from Round Valley Reservoir had the potential to heat water in Butte Creek. However, years of water temperature monitoring data have shown that, due to the input of cool water from springs near Coon Hollow and WBFR basin snow melt, releases from Round Valley Reservoir occurring in the summer (June –August) do not increase water temperatures at HDD and thus, would not increase the temperatures in Butte Creek. As a result, flow releases from Round Valley Reservoir have been used to augment releases from Philbrook Reservoir to maximize storage availability during the hottest time of the holding period (mid-July to mid-August). In years prior to 2026, water was released from Round Valley Reservoir between early May and mid-July when there was available capacity in the Hendricks canal. Depending on water availability from snow melt, releases continue for a period of approximately one to two months. Additionally, water was not released from Philbrook Reservoir until the flow from Round Valley Reservoir diminished or significantly high air temperatures occurred. Historically, PG&E notified the Resource Agencies when water releases commence from Round Valley Reservoir. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 6 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Philbrook Reservoir Water stored in Philbrook Reservoir is the main source used to supplement flows in Butte Creek during the adult CVRSCS holding period. Monitoring data shows that cooler water released from the bottom of Philbrook Reservoir (i.e., the cold-water pool) increases in temperature while traveling through the system and reaches thermal equilibrium at HDD. The Resource Group has agreed that it is a combination of total flow (decreased travel time, increased mass of water subject to heating) and cold-water releases that help minimize effects of ambient air temperatures to water temperatures in Butte Creek. Generally, the cool-water pool in Philbrook is depleted in late July to early August and release temperatures increase through August (e.g., maximum daily average release temperature of 20.3 ºC occurred on August 17, 2018); however, monitoring data show that after the beginning of August the thermal regime in the basin is such that releases with higher temperatures actually cool as the water travels to HDD (sun declination is lower, canyon walls shade the stream, and cool evenings predominate). When management of Philbrook flows began in 1998, the outflow from the reservoir increased in response to forecasted heat events and then returned to pre- heat levels to save water. This resulted in a large amount of residual water storage at the end of the holding period, which was then released in September to make room in the reservoir for upcoming winter storms (Exhibit B). The Resource Group has moved away from this short-term response to heat events. The contemporary approach is to release elevated outflow from Philbrook incrementally and hold flow volume consistent until weather conditions or the Resource Group warrants a change in flows. This approach maximizes the use of storage during the holding period and minimizes the amount of residual storage at the end of the holding period. This water management approach creates a hydrograph that resembles stair steps and is referred to informally in this document as stepwise management. Although the Resource Group was transitioning to a stepwise management approach in previous years, 2014 was the first year in which this pattern of management was fully employed (Exhibit B). Since 2014, water management followed a basic framework. When diversion of the WBFR at the HDD does not maintain targeted flow in the Hendricks Canal, outflow from the reservoirs is DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 7 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company increased. Outflow from reservoirs was incrementally increased or decreased (based on predicted weather and hydrologic conditions. If no heat event is predicted and flows remain steady in the canal; releases are held steady until the next heat event is forecasted. Using this strategy, releases are increased so maximum flow is reached during the hottest period of the summer (mid-July to early August). Maximum release is held for a short period and duration, which is based on the amount of water available for the remainder of the holding period. Outflow from the reservoir is then decreased incrementally. The timing, duration, and quantity of flow depends on the balance between heat events, remaining storage availability, and seasonal timing. The Resource Group has concluded that this release pattern is beneficial since it utilizes most of the stored Philbrook water from late June through late July when air and Butte Creek water temperatures are at their highest during the holding period. The stepwise release pattern from Philbrook Reservoir (as described above) was used during the 2014 – 2020 & 2022-2025 holding periods. Releases deviated from this stepwise release pattern in 2021 because of limited flows and water availability. PG&E uses a combination of the meteorological forecast and the volume of stored water in Round Valley and Philbrook Reservoirs to determine duration and flow rate released from the reservoirs. This additional information facilitates proactive management of the stored water supply. CDFW provides monitoring data and information about abundance, distribution, and health of fish, and temperatures at Quartz Bowl to help inform and /support Resource Group decisions. Collectively, the Resource Group agrees to a flow proposal based on the information provided. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 8 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 2.0 WATER YEAR TYPE AND OPERATIONS 2.1 Water Year Type for 2026 The 2026 Water Year Type is currently a Normal water year type per the definition of the license. The Department of Water Resources (DWR) Bulletin-120 May forecast states that the Feather River Basin April runoff into Oroville is 67% of historical average. Exhibit C lists historical runoff forecasts and water year types since 1998. 2.2 Reservoir Operations for 2026 In the late summer and early fall of 2023, PG&E completed a geotechnical investigation on the spillway at Round Valley Reservoir in support of a recommendation from the 2015 FERC Part 12D Dam Safety Inspection. To mitigate risks identified with the data collected during the 2023 Round Valley Reservoir Geotechnical Investigation, PG&E implemented an internal justification for continued operation (JCO) limit of 5 feet below spill crest on Round Valley Reservoir Elevation. This limit reduces the maximum useable water storage from 1187 acre- feet to 739 acre- feet. The Round Valley low-level outlet (LLO) was closed on April 1, 2026, and then reopened on April 21, 2026, to maintain compliance with PG&E’s internal JCO threshold as mentioned above. The Philbrook LLO is scheduled to continue releasing MIF (2 cfs) unless the temporary flow modification discussed in Section 2.4 is approved, in which case PG&E will follow the amended MIF. PG&E will keep the Resources Agencies informed regarding LLO operations at both reservoirs In 2025, PG&E completed a seismic stability analysis for Philbrook Dam and filed the results of the seismic stability and associated JCO with FERC on February 25, 2025. The seismic stability study indicated unsatisfactory performance of the dam under the seismic loading scenarios DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 9 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company considered when the reservoir is at its normal maximum water surface elevation (NMWSE) of 5,552.5 feet (National Geodetic Vertical Datum of 1929 [NGVD29]), which equates to an operational gage height of 60 feet. Considering these results, the risk of post-seismic deformation has the potential downstream consequence of uncontrolled release of the reservoir. A JCO threshold has been established at Philbrook as an interim risk reduction measure (IRRM) until a long-term solution has been selected and implemented. PG&E will manage the Philbrook Reservoir at a target elevation of 5,542.7 feet NGVD29 (50.2’operational gage height), which is 9.8 feet below the NMWSE and corresponds to a decrease of approximately 1,560 acre-feet of its storage capacity. As a result of the JCO, the spillway radial gate will not be used, and no flashboards will be installed in 2026. Reservoir operation for the holding period is as follows: 1. Releases from Round Valley Reservoir will begin when there is adequate capacity in the Hendricks Canal. The receiving capacity of the Henrick Canal is generally dependent upon water year type and the timing of snowmelt. Due to the elevation restriction required by the JCO, PG&E will only be able to store and use approximately 739 acre-feet of water from Round Valley Reservoir. As of April 17, 2026, Round Valley Reservoir had reached the 739-acre foot threshold. Releases will begin sometime from mid-May to late June. PG&E will notify the Resource Agencies when water releases commence from Round Valley Reservoir. 2. As Round Valley Reservoir nears its minimum elevation, PG&E will consult with the Resource Agencies to determine when releases from Philbrook Reservoir should be increased to avoid a drop in canal flows when Round Valley Reservoir is depleted PG&E will closely monitor the drawdown of Round Valley Reservoir as the minimum elevation is approached. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 10 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 3. The Resource Group will determine the initial flow rate released from Philbrook Reservoir which will be different this year than in previous years because of the limitations of Philbrook Reservoir. Factors considered in establishing the flow rate released from Philbrook (release) used include the date upon which releases commence the objective of reserving water for a possible extreme heat event, the level of natural flows, and the objective of maintaining the highest possible flows through the DeSabla Forebay. 4. The stepwise management strategy will be used to release water from Philbrook Reservoir again in 2026. The stepwise management strategy is the preferred strategy; however, the outflow from the reservoir may increase in response to forecasted heat events and then return to pre-heat event levels to save water based on real-time meteorology and water availability. The Resource Group collectively may recommend conserving available water based on real time information and discussion. To take advantage of available water storage and to maximize cooling during the hottest part of the holding period (early-July to late- August), releases from Philbrook Reservoir should be initiated prior to September. This approach will help promote optimal water temperatures and efficient use of stored water. 5. The Resource Group will hold weekly virtual meetings from June to mid-September (as needed) to discuss outflow from the reservoirs. The Resource Group will determine the stepwise increases in outflow (approximately 5 to 10 cfs each) based on predicted heat events. Weekly virtual meetings will also include discussion of weather forecast, reservoir levels, pre-spawning mortality updates (if conducted), water temperatures (as measured at the holding pool “Quartz Bowl”) by CDFW, and proposed outflow from Philbrook Reservoir. In discussing flow changes to the reservoirs, the Resource Group must consider that the release valves from both reservoirs must be operated manually, and the travel time of the water released from these reservoirs to the Lower Centerville Diversion Dam (LCDD) is approximately 21 to 29 hours. Travel time of operator to the valve locations is approximately 1½ hours during weekdays and may be up to 4 hours on weekends. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 11 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 6. A flow of 60 cfs is targeted to reduce residence time and minimize heating of water as it moves through the Forebay. The 60 cfs target flow through the DeSabla Forebay will be reviewed during the summer on the weekly calls described above to determine if this rate should be adjusted based on the available releases from Philbrook Reservoir. 7. Water temperature monitoring by PG&E will continue in 2026 at eight stations (Exhibit E), five of which have been used prior to relicensing (since 1998). Installation of temperature loggers will occur in June or as soon thereafter when safe access to the stream channels as possible. Data will be reported to the Resource Agencies during the 2027 Annual Operations Meeting. 8. DWR stream gage BBW (PG&E Gage BW-12) will be used as an indicator of water temperatures in the Project waters that are diverted from the WBFR. BBW data is available on CDEC and provides hourly temperature and flow data. 2.3 Lower Centerville Canal Operations for 2026 LCC has been out of service since 2013 and will remain out of service. 2.4 2026 Minimum Instream Flow Temporary Amendment PG&E submitted a minimum instream flow (MIF) temporary flow modification request with FERC on February 6, 2026. The 2026 request is similar to the previous requests filed with FERC on June 12, 2024, and May 6, 2025. The 2026 flow modification would change MIF requirements to the WBFR below HDD, which is PG&E gage BW-40, from 15 cfs to 7 cfs measured as an average MIF over a 48-hour period. The 2026 flow modification would change the instantaneous MIF at PG&E gage BW-3 from 2 cfs to a target MIF between 1 cfs and 2 cfs averaged over a 48- hour period. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 12 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company The temporary flow modification was approved on May 6, 2026, and will end on September 30, 2026. The 2026 temporary MIF flow modification will provide flexibility to transfer the maximum amount of water into the Hendricks Canal from the WBFR to increase flow through the DeSabla Forebay to Butte Creek during the hottest part of the summer holding period for CVSRCS in Butte Creek. The JCO at Philbrook Reservoir has lowered the maximum storage capacity of the reservoir, and the temporary MIF flow reductions in the WBFR will allow PG&E to operate like a dry water year. This operating mode will allow PG&E to conserve water resources and maximize water delivery from the WBFR to the Butte Creek during the hottest parts of the summer. This will help maintain the flow through the DeSabla Forebay above 60 cfs to help decrease water residence in the Forebay and minimize heating. During the 2026 CVSRCS holding period, this amendment will allow PG&E greater flexibility to operate around the MIFs while staying compliant during short- lived drops in instream flow readings. In addition, the flow modification at BW-40 will maximize the delivery of flow released from Philbrook to Butte Creek instead of being used to buffer flow to meet instantaneous MIF. 2.5 Contingency for Extreme Heat Event During the Holding Period In anticipation of a possible high ambient air temperature event, the following actions will be taken: 1. Ambient air temperature conditions are a significant factor in determining actual water temperatures in Butte Creek. Starting on June 1 or at such time as the Resource Group determines, PG&E will prepare a weather forecast for the Project area by noon each Monday and Thursday. The weather forecast will be based on information from USFS weather stations at Cohasset and Chester. PG&E will provide an email copy of the forecast to the Resource Agencies. If air temperatures of more than 105ºF for two or more days during the next seven- day period are forecasted at the Cohasset weather station, with the potential for compression heating at higher elevations as confirmed by data from the Chester location, PG&E will send an email to each Resource Agency representative identified in paragraph 4 below advising DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 13 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company them that an extreme heat event is forecasted. If the next forecast confirms that an extreme heat event has started or is imminent within the next two days and is expected to continue for over two days, PG&E will send a second email or phone to one of the individuals at each Resource Agency identified in paragraph 4 to discuss actions to be taken. If personal contact cannot be made and PG&E still believes action needs to be taken, it will initiate efforts to modify Project operation as discussed in paragraphs 2–4 below. If action is taken, PG&E will send a third email or phone the Resource Agencies and explain the actions taken. 2. PG&E will coordinate weekly conference calls with the Resource Agencies during the CVSRC holding period. Increased call frequencies will be conducted as requested and agreed upon by the Resource Group. These conference calls are usually conducted from early June through mid-September (as needed). During these conference calls the Resource Group will discuss the results of pre-spawning mortality surveys (if provided by CDFW or NMFS), meteorological forecasts, water temperatures recorded by CDFW at Quartz Bowl, and flows and storage in Philbrook Reservoir. 3. The actual amount of water released from Philbrook Reservoir during a confirmed extreme heat event will depend on PG&E’s assessment of existing conditions and recommendations received from the Resource Agencies in response to the emails. 4. The individuals to whom PG&E will send e-mails under this section are: a. Tracy McReynolds (CDFW) – Tracy.McReynolds@wildlife.ca.gov, (530) 333-7746 b. Grant Henley (CDFW)- Grantton.Henley@wildlife.ca.gov, (916) 272-4152 c. Anna Allison (CDFW) – Anna.allison@wildlife.ca.gov, (916) 272-4373 d. Beth Lawson (CDFW) – Beth.Lawson@wildlife.ca.gov, (916) 358-2875 e. Ellen Roots (NOAA Fisheries) – ellen.roots@noaa.gov, (916) 930-3722 f. Yvette Redler-Medina (NOAA Fisheries) - yvette.redler-medina@noaa.gov g. Cathy Marcinkevage (NOAA Fisheries) - cathy.marcinkevage@noaa.gov h. Kurt Sable (USFS)– kurt.sable@usda.gov, 530-616-1823 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 14 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company i. Eric Bradbury (SWRCB) – Eric.Bradbury@waterboards.ca.gov, (916) 327-9401 j. Stephanie Millsap (USFWS) - Stephanie_Millsap@fws.gov, (916) 930-2658 k. Brittany Reaves (USFWS) - brittany_reaves@fws.gov, (530) 365-7150 2.6 Spawning Flows in Butte Creek As in previous years, it is best to reduce flow from the WBFR watershed during the fall so that redds in Butte Creek are not at risk of being dewatered if an emergency outage occurs on the Hendricks. In the past, flows from the WBFR were decreased around mid-September when CVSRCS are expected to begin spawning, mean daily temperature decreases naturally, and canal use has less of a cooling effect on water temperature in Butte Creek. Decreasing flows mid- September ensures that fish spawn and rear in the natural flows of Butte Creek, reducing the potential for redd dewatering. Additionally, this decreases the risk of significant flow reduction in Butte Creek in the case of an emergency canal outage. 2.7 Scheduled and Emergency Maintenance and Operations 1. Maintenance Outage Scheduling – To minimize the disruption of flows in Butte Creek during times that are sensitive to CVSRCS holding in Butte Creek, PG&E usually plans to take scheduled canal outages as early as possible in the year. This submission includes all planned outages for PG&E owned tunnels, conduits, or penstocks under FERC licenses (Exhibit D). a. On August 10, 2023, an incident occurred at Butte Canal which removed the canal from service through 2024. Butte Canal will remain out of service for 2026. 2. Unplanned Outages (2024-2026) - Winter storms, disruption in canal flows caused by slides or fallen trees, unexpected electric transmission system outages, Public Safety Power Shutoffs (PSPS), and other hazardous conditions can disrupt normal Project operation. PG&E shall use its best efforts to minimize impacts that may result from these conditions, including the actions outlined below: DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 15 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 3. Public Safety Power Shutoff (PSPS) - As part of our Community Wildfire Safety Program, PG&E is implementing additional precautionary measures to help reduce the risk of wildfires. For public safety, it may be necessary for us to turn off electricity as a last resort when extreme fire danger conditions are forecasted. This is called a "Public Safety Power Shutoff." See section below for more information on impacts and responses. 4. Unit Separation from Electric Grid - If the electric transmission grid, generating unit, or a critical support system experiences a problem, or in the event of a PSPS, the generating units automatically separate from the grid and the flow of water to the units is directed away from the turbine. At the Toadtown and DeSabla powerhouses, this is done by means of a bypass device that directs the flow through an energy dissipator bypass and allows the water to continue moving at approximately the same flow. PG&E will adjust the automatic bypass opening during the summer to reasonably correspond to the operational flow of the powerhouse. The shift from the generating unit to the bypass facility may result in a minor release of turbidity caused by sediment that may have built- up in the bypass system since its last use. During a unit separation or PSPS event, standby portable generators are deployed to supply power to station batteries that power bypass system controls. During a separation from electric grid, PG&E increases patrol of canals as some remote operation of equipment and some remote monitoring will not be available. In preparation for PSPS events, PG&E staffs additional personnel to remediate any issues that arise during the duration of the event. 5. Winter Operation and Canal Emergencies – Much of the Project’s canal system traverses steep forested lands. During times of high rainfall and/or high winds, slides, rock falls, and fallen trees can damage canals or block flows. To minimize the potential for damage in the event of blockage or failure of a canal or flume, PG&E may reduce canal flows or dewater canals in advance of such weather events. In addition, emergency spill gates are located at several locations that are equipped with devices that can be operated remotely to spill water DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 16 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company at various locations along the canals. PG&E has sensors that report canal water level to the operator at the Rock Creek Switching Center. This location is staffed 24 hours a day, 7 days a week, 365 days a year. If a sensor detects an unexpected change in the canal water level, an alarm is sent to alert the operator on duty. The operator will then dispatch personnel to the location to determine if immediate action can or should be taken to remove water from the canal by activating an emergency spill gate. The emergency spill gates are placed at locations where the channel through which the water will travel is generally protected by rocks and boulders. However, turbidity is possible from vegetative or other debris that may have accumulated in the channel since its last use. Spill channels are routinely inspected at the beginning of the winter season and are typically operated once during a winter high flow event to maintain the prescriptive right for the spill channel and keep the release gate clear of material. This operation results in an incremental increase in the turbidity of Butte Creek for a short period of time, which is typically already elevated during high flow events. Operation of the spill channels that may not be well protected and could likely result in turbidity increases, other than the annual winter operation discussed above, will be operated for emergency purposes only. To avoid releasing water into a damaged canal after a storm event, the canal is patrolled on foot prior to restoring flow. 3.0 WATER QUALITY MONITORING PG&E will monitor water temperature at eight seasonal stations during 2026. These are in addition to the real-time, permanent CDEC station BBW (PG&E gage BW-12). Temperature monitoring will generally be conducted between June and September. Results from 2026 will be presented at the Annual Operations and Management Meeting in 2027. Monitoring locations are identified in Exhibit E. Prior to the start-up of a canal or powerhouse after an outage, which may result in the possible release of turbidity to Butte Creek, PG&E will monitor water quality using two existing continuous DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 4.0 Consultation 17 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company monitoring turbidity sensors located in Butte Creek; one sensor is located at the LCDD, the other sensor is on a wing wall of the CVPH tailrace. In the event of a canal failure, spill gate operation or other release that results in a potential increase of turbidity in Butte Creek, PG&E will secure water quality samples to the extent practicable and taking into consideration personnel safety. The monitoring will be conducted using either grab samples collected by PG&E and tested for turbidity or data from the two continuous monitoring turbidity meters (noted above), set to sample every 15 minutes. Sampling locations will generally be immediately upstream of the dam or point of diversion and approximately 300 feet downstream of the point of release or return to surface waters. If the point of release to surface waters is not reasonably accessible by vehicle, PG&E will sample at the nearest downstream location that can be safely and readily accessed. Turbidity data collected during a canal start-up following a long-term outage of greater than 90 days, will be made available to one representative at each of the Resource Agencies identified in Section 2.5, in a timely fashion. Water temperature data will be provided to Resource Agency representatives upon request. 4.0 CONSULTATION On August 21, 1997, the FERC issued an order placing temperature restrictions on releases from PG&E’s storage reservoirs in the upper WBFR watershed. On August 20, 1998, the FERC revised its order to allow for modification of the criteria upon mutual agreement of the NMFS, CDFW and USFWS. Since 1999, this agreement has been accomplished by way of an annual operations plan for these reservoirs. The reservoir operation varies based on water year conditions. Pursuant to FERC’s August 21, 1998 order, this Operations Plan is annually updated and modified as appropriate in consultation with the Resource Agencies. The FERC Order requires the licensee to notify FERC within 30 days after reaching agreement on the O&M Plan. PG&E will meet at least annually with the interested Resource Agencies to discuss and review this O&M Plan. In addition, PG&E will continue to provide updates (generally by email) on Project DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 4.0 Consultation 18 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company operations and events to at least one representative from each of the individual Resource Agencies identified in Section 2.5. A summary report will be prepared on annual operations and monitoring data, which will include water and air temperatures, reservoir and conveyance operations and actions taken to minimize effects on the CVSRCS. Nothing in this O&M Plan will be construed as modifying any of the terms and conditions of the DeSabla-Centerville license, FERC No. 803, or in any manner limiting the jurisdiction of the FERC. In the event of any conflict between any of the provisions of this O&M Plan and the license, the provisions of the license will control. PG&E will work with the Resource Agencies, and others, as appropriate, to seek ways to promote prudent land management practices by others where such practices may directly or indirectly impact safe, reliable canal operations. Nothing in this O&M Plan will be construed as either PG&E or the Resource Agencies accepting responsibility for conditions or damage that may be the result of the actions, or inactions, of others. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit A 19 Final– May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 5.0 REFERENCES PG&E. 2007. DeSabla-Centerville Hydroelectric Project. FERC Project No. 803. License Application. Appendix E6.2.2.3-G Calibration and Scenarios Report. 14 pp. PG&E. 2015. Final Project Operations Plan – 2015. Pacific Gas and Electric Company DeSabla- Centerville Project (FERC No. 803). June 18, 2015 PG&E. 2025. DeSabla-Centerville project (FERC No. 803). Final 2025 Operations and Maintenance Plan. Exhibit A. Map of Project Area DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit B 20 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit B. Comparison of Philbrook Reservoir Storage Usage The graph shows how the management of release has changed through time. From 1998 to 2013, the release of outflow was based on preserving the cold-water pool by increasing flows before and after meteorological forecasted heat storms. This resulted in peak average releases occurring towards the end of the holding period (Average Release (1998-2013). From 2014 to 2025, flow release was based on providing water in a stepwise pattern throughout the first part of the holding period and is decreased in a stepwise pattern towards the latter half of the holding period as storage decreases. This management strategy maximizes outflow during the peak summer period when the flow is most effective at temperature mitigation in downstream reaches (Average Release (2014-2025). A variation of this management strategy occurred in 2021 when the Resource Group managed flows with limited storage during an extremely dry year. 0 10 20 30 40 50 60 6/1 6/9 6/17 6/25 7/3 7/11 7/19 7/27 8/4 8/12 8/20 8/28 9/5 9/13 9/21 9/29 Re l e a s e F l o w ( c f s ) Release Range (1998 - 2013)Release Range (2014-2025) Average Release (1998 - 2013)Average Release (2014-2025) Modified release regime: Weighted toward peak period of summer temperatures when available DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit C 21 Final- May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit C. Historical Runoff Forecast and Water Year Type Since 1998 Water Year Forecast Year Type 1998 10% April 2026) % Runoff Forecasts are the published May 1 Bulletin 120 forecast of April – July unimpaired runoff into Oroville Reservoir computed by the State of California at that time. Water Year Type is “Dry” if the runoff forecast is 50% or less. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit D 22 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit D. 2026 and 2027 Projected Scheduled Maintenance and Outages DESABLA-CENTERVILLE 2026 & 2027 MAINTENANCE AND OUTAGE SCHEDULE LOCATION DURING OUTAGE STRUCTURE Start Date End Date TOADTOWN Canal Canal Annual Canal 3/30/2026 5/04/2026 HENDRICKS CANAL Canal Annual Canal 3/30/2025 5/04/2026 TOADTOWN Canal Canal Annual Canal 3/29/2027 4/25/2027 HENDRICKS CANAL Canal Annual Canal 3/29/2027 4/25/2027 DeSabla-Centerville Project (FERC Project No. 803) 2025 Operations and Maintenance Plan Exhibit E 23 Final – May 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit E. 2026 PG&E Seasonal Monitoring locations 1. Philbrook Creek (PG&E Gage BW-3) at release * (Temperature and Flow) 2. WBFR at Hendricks Head Dam (PG&E Gage BW-40) * (Temperature and Flow) 3. BW-12 Gage Station reported to CDEC (BBW)* (Temperature and Flow) 4. Total canal inflow to DeSabla Forebay * (Temperature and Flow) 5. Butte Creek above DeSabla Powerhouse 6. DeSabla Powerhouse tailrace * (Temperature and Flow) 7. Butte Creek at LCDD * (Temperature, Turbidity, and Flow) 8. Butte Creek at Centerville Powerhouse (Temperature and Turbidity) ENCLOSURE 2 5/27/26, 2:37 PM lnbox -Drummond, Duncan -Outlook <B1Mb@pge.com>; Ramirez-Doble, Sky <S9RV@pge.com>; Reyes, Catalina <CERh@pge.com>; Lent, Michelle <M4LQ@pge.com>; TIMOTHY SAGRAVES <tsagr@aol.com>; Williamshen, Brian <BOW2@pge.com> Subject: [EXTERNAL] Re: DeSabla-Centerville 2026 Annual Operations and Maintenance Meeting This email has been received from outside of DOI - Use caution before clicking on links, opening attachments, or responding. Anna, Thank you for your review and comments. I have incorporated CDFW's comments into the DeSabla-Centerville 2026 Annual Operations and Maintenance Plan (Plan). I have attached a redlined version of the document so you can review the revisions. I plan on submitting the Plan to FERC early next week. In regard to your comments: "Page 11; Number 6. Discusses the flow target of 60 cfs to reduce residence time and minimize water heating as it moves through the Forebay. During the Resource Agencies O&M meeting, 4/29/26 Teams call, PG&E announced several times that the target flow would be 40 cfs. CDFW requests that 60 cfs will be the target flow to reduce residence time and minimize heating of water as it moves through the Forebay, as written in the document. In previous years, including 2025, the target has been 60 cfs, even with reduced Philbrook and Round Valley capacity. Since 2024, PG&E has further limitations due to the Butte Canal outage*." 60 cfs will continue to be the target flow through the DeSabla Forebay,_which is consistent with the Plan language. During the meeting, we did discuss the maximum release of approximately 40 cfs from Philbrook Reservoir, but I have no notes regarding lowering the target flows to 40 cfs. It appears that PG&E did not clearly convey that the target flow would remain at 60 cfs during 2026. Please contact me if you have any additional questions or concerns. Duncan Drummond Hydroelectric License Coordinator DeSabla-Centerville Project (FERC 0803) Pacific Gas & Electric 530.215.9678 From: Allison, Anna@Wildlife <Anna.Allison@wildlife.ca.gov> Sent: Friday, May 22, 2026 3:06 PM To: Drummond, Duncan <DGDH@pge.com>; Lawson, Beth@Wildlife <Beth.Lawson@wildlife.ca.gov>; https://outlook.office.com/mail/inbox/id/MkALgAAAAMHYQDEapmEc2byACqAC%2FEWg0ArOGv%2FVov3UOJktS6GcZCWgAlzMxp6QM?native... 2/10 5/27/26, 2:37 PM lnbox -Drummond, Duncan -Outlook ellen.roots@noaa.gov; Henley, Grantton@Wildlife <Grantton.Henley@Wildlife.ca.gov>; McReynolds, Tracy@Wildlife <Tracy.McReynolds@wildlife.ca.gov>; Millsap, Stephanie D <stephanie_millsap@fws.gov>; Yvette Redler-Medina <yvette.redler-medina@noaa.gov>; Aguirre orozco, Victor -FS, CA <victor.aguirreorozco@usda.gov>; Kurt Sable <kurt.sable@usda.gov>; Bradbury, Eric@Waterboards <Eric.Bradbury@Waterboards.ca.gov> Cc: Forrest, Kathleen <KAFM@pge.com>; Herman, Andie <AEHb@pge.com>; Ivie, Pancho <PLl2@pge.com>; Jones, Noel <NMJ6@pge.com>; Lerossignol, Gabriel <Gxle@pge.com>; Meyers, Ben <B1Mb@pge.com>; Ramirez­ Doble, Sky <S9RV@pge.com>; Reyes, Catalina <CERh@pge.com>; Lent, Michelle <M4LQ@pge.com>; TIMOTHY SAGRAVES <tsagr@aol.com>; Williamshen, Brian <BOW2@pge.com> Subject: Re: DeSabla-Centerville 2026 Annual Operations and Maintenance Meeting WARNING: This message is from an external source. Verify the sender and exercise caution when clicking links or opening attachments. Good morning, Thank you for participating in the 2026 DeSabla-Centerville Annual Operations and Maintenance Plan meeting. I have attached the presentation slide deck for your reference. Please submit any edits or comments on the Plan to me no later than May 27,2026. Contact me directly if you have any questions. Duncan Drummond Hydroelectric License Coordinator DeSabla-Centerville Project (0803) Pacific Gas & Electric 530.215.9678 From: Drummond, Duncan <DGDH@Qge.com> Sent: Monday, March 2, 2026 6:42 AM To: Drummond, Duncan <dgdh@Qge.com>; Allison, Anna@Wildlife <Anna.Allison@wildlife.ca.gov>; https://outlook.office.com/mail/inbox/id/MkALgAAAAMHYQDEapmEc2byACqAC%2FEWg0ArOGv%2FVov3UOJktS6GcZCWgAlzMxp6QM?native... 5/10 5/27/26, 2:37 PM lnbox -Drummond, Duncan -Outlook cathv..marcinkevag�noaa.gov <cathv..marcinkevag�noaa.gov>; ellen.roots@noaa.gov <ellen.roots@noaa.gov>; Grant Henley (Grantton.Henley.@Wildlife.ca.gov) <Grantton.Henley.@Wildlife.ca.gov>; Leong, Tristan <tristan.leong.@usda.gov>; McReynolds, Tracy@Wildlife <Tracv..McRev.nolds@wildlife.ca.gov>; Millsap, Stephanie D <steP-hanie millsaP-..@fws.gov>; Yvette Redler-Medina <.v.vette.redler-medina@noaa.gov> Cc: Brunswick, Betsy <BMB7@P-ge.com>; Cheslak, Edward <EFC3@P-ge.com>; Forrest, Kathleen <KAFM@P.ge.com>; Herman, Andie <AEHb@.P-ge.com>; Ivie, Pancho <PLl2@P-ge.com>; Jones, Noel <NMJ6@P-ge.com>; Lerossignol, Gabriel <GxLe@P-ge.com>; Meyers, Ben <B1Mb@P-ge.com>; Ramirez-Doble, Sky <S9RV@P-ge.com>; Reyes, Catalina <CERh@P.ge.com>; Lent, Michelle <M4L0@P-ge.com>; TIMOTHY SAGRAVES <tsagr.@aol.com>; Williamshen, Brian <B0W2@P-ge.com>; Lincicum, Brent <NBL2@P-ge.com> Subject: Re: DeSabla-Centerville 2026 Annual Operations and Maintenance Meeting Good morning, Thank you to everyone that has provided their availability for the annual DeSabla-Centerville Operations and Maintenance Plan meeting for 2026. f you need to update your availability since you responded to the pool, please e-mail me directly. If you haven't responded to the poll and would like to attend, please confirm your availability by noon today using this Doodle Pool Link: httP-s://doodle.com/grouP--P-OII/P-articiP-ate/eV2OEM9e I hope you have a great day. Duncan Drummond Hydroelectric License Coordinator Pacific Gas & Electric 530.215.9678 https://outlook.office.com/mail/inbox/id/MkALgAAAAMHYQDEapmEc2byACqAC%2FEWg0ArOGv%2FVov3UOJktS6GcZCWgAlzMxp6QM?native... 7/10 ENCLOSURE 3 PACIFIC GAS AND ELECTRIC COMPANY DeSabla-Centerville Hydroelectric Project FERC No. 803 2026 OPERATIONS AND MAINTENANCE PLAN Draft Prepared By: MayApril 2026 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan TABLE OF CONTENTS 1.0 Introduction ............................................................................................................................ 3 1.1 Project Features .............................................................................................................. 3 1.2 Project Benefits to Butte Creek Habitat .......................................................................... 4 1.3 Background ..................................................................................................................... 4 1.3.1 The Resource Group.................................................................................... 4 1.3.2 Project Reservoirs ....................................................................................... 5 2.0 WATER YEAR TYPE AND OPERATIONS ................................................................. 8 2.1 Water Year Type for 2026 .............................................................................................. 8 2.2 Reservoir Operations for 2026 ........................................................................................ 8 2.3 Lower Centerville Canal Operations for 2026 .............................................................. 11 2.4 2026 Minimum Instream Flow Temporary Amendment .............................................. 11 2.5 Contingency for Extreme Heat Event During the Holding Period ............................... 12 2.6 Spawning Flows in Butte Creek ................................................................................... 14 2.7 Scheduled and Emergency Maintenance and Operations ............................................. 14 3.0 WATER QUALITY MONITORING ........................................................................... 16 4.0 CONSULTATION .......................................................................................................... 17 5.0 REFERENCES ................................................................................................................ 19 TABLE OF EXHIBITS Exhibit A. Map of Project Area .................................................................................................... 19 Exhibit B. Comparison of Philbrook Reservoir Storage Usage .................................................... 20 Exhibit C. Historical Runoff Forecast and Water Year Type Since 1998 .................................... 21 Exhibit D. 2026 and 2027 Projected Scheduled Maintenance and Outages ................................. 22 Exhibit E. 2026 PG&E Seasonal Monitoring locations ................................................................ 23 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 3 FinalDraft – MayApril 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 1.0 INTRODUCTION The Operations and Maintenance Plan’s (O&M Plan) objective is to manage flows from the DeSabla-Centerville Hydroelectric Project (Project) reservoirs to support holding, spawning, and rearing Central Valley spring-run Chinook salmon (Oncorhynchus tshawytscha; CVSRCS) use in the reaches of Butte Creek below the DeSabla Powerhouse during 2026. It also documents Pacific Gas and Electric Company’s (PG&E) scheduled outages that allow for the Project maintenance activities. In addition, this O&M Plan outlines the procedures and practices PG&E will strive to follow in the operation of the Project to enhance and protect habitat for CVSRCS. Finally, this O&M Plan provides the basis for modification of the reservoir temperature release criteria established in the Federal Energy Regulatory Commission (FERC) “Order Approving Water Temperature Study Report” issued August 21, 1997, as amended by FERC’s “Order Amending Temperature Requirements” issued August 20, 1998. 1.1 Project Features The DeSabla – Centerville Hydroelectric Project includes the following features which are depicted on the project map which is included with this O&M Plan as Exhibit A: Reservoirs and Forebays:  Round Valley Reservoir (also known as Snag Lake)  Philbrook Reservoir  DeSabla Forebay Canals and related features:  Butte Canal (out of service since 2023)  Hendricks Canal  Toadtown Canal  Upper Centerville Canal  Lower Centerville Canal (LCC; out of service since 2014)  associated diversion dams, feeders, and spillway channels DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 4 FinalDraft – MayApril 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Powerhouses:  Toadtown Powerhouse  DeSabla Powerhouse  Centerville Powerhouses (CVPH) 1.2 Project Benefits to Butte Creek Habitat Water diverted from the West Branch Feather River (WBFR) at the Hendricks Head Dam (HDD); and releases from Philbrook and Round Valley Reservoirs can increase the total flow available in Butte Creek below DeSabla Powerhouse by up to approximately 40% in July and August (depending on water availability in Butte Creek). Water imported from the WBFR provides additional water to moderate water temperatures in reaches of Butte Creek used by CVSRCS for over-summering by providing releases from Philbrook Reservoir when storage is available. The increased flow from the Philbrook Reservoir releases help minimize heating by decreasing travel time in the Hendricks Canal and by reducing the residence time in the DeSabla Forebay. 1.3 Background 1.3.1 The Resource Group On August 21, 1997, the FERC issued an Order placing temperature restrictions (17º C at Round Valley and 18º C at Philbrook) on the water releases from these dams. On August 20, 1998, and 2020-2021, the FERC revised its Order to allow for modification of the criteria upon mutual agreement of the National Marine Fisheries Service (NMFS), the California Department of Fish and Wildlife (CDFW), and the United States Fish and Wildlife Service (USFWS); PG&E has also included the State Water Resource Control Board (SWRCB), and United States Forest Service (USFS) in this consultation process. These five agencies are referred to as the Resource Agencies in this Plan. Since 1999, this agreement has been accomplished by way of an annual O&M Plan. Reservoir operation has been based on expected water year conditions. Pursuant to FERC’s August 21, 1998, Order, this O&M Plan is annually updated and modified as appropriate in consultation with the Resources Agencies. This consultation group, composed of PG&E and the Resource DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 5 FinalDraft – MayApril 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Agencies, is called the Resource Group in the remainder of this Plan. Starting in 2016, a schedule of annual maintenance outages of the DeSabla-Centerville Canals was included in this O&M Plan. 1.3.2 Project Reservoirs The Project storage reservoirs (Round Valley and Philbrook Reservoirs) are in the WBFR watershed. Project diversions are made from this drainage at the HDD. Due to the larger maximum storage capacity and depth of Philbrook Reservoir (5,000 acre-feet) relative to Round Valley Reservoir (1,200 acre-feet), the water temperature tends to stay cooler for a longer period in Philbrook Reservoir. Round Valley Reservoir Since 1998 PG&E has released water from Round Valley Reservoir first, to effectively manage the temperature of water released into Butte Creek. During initial management of the Reservoirs there was concern that releases from Round Valley Reservoir had the potential to heat water in Butte Creek. However, years of water temperature monitoring data have shown that, due to the input of cool water from springs near Coon Hollow and WBFR basin snow melt, releases from Round Valley Reservoir occurring in the summer (June –August) do not increase water temperatures at HDD and thus, would not increase the temperatures in Butte Creek. As a result, flow releases from Round Valley Reservoir have been used to augment releases from Philbrook Reservoir to maximize storage availability during the hottest time of the holding period (mid-July to mid-August). In years prior to 2026, water was released from Round Valley Reservoir between early May and mid-July when there was available capacity in the Hendricks canal. Depending on water availability from snow melt, releases continue for a period of approximately one to two months. Additionally, water was not released from Philbrook Reservoir until the flow from Round Valley Reservoir diminished or significantly high air temperatures occurred. Historically, PG&E notified the Resource Agencies when water releases commence from Round Valley Reservoir. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 6 FinalDraft – MayApril 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Philbrook Reservoir Water stored in Philbrook Reservoir is the main source used to supplement flows in Butte Creek during the adult CVRSCS holding period. Monitoring data shows that cooler water released from the bottom of Philbrook Reservoir (i.e., the cold-water pool) increases in temperature while traveling through the system and reaches thermal equilibrium at HDD. The Resource Group has agreed that it is a combination of total flow (decreased travel time, increased mass of water subject to heating) and cold-water releases that help minimize effects of ambient air temperatures to water temperatures in Butte Creek. Generally, the cool-water pool in Philbrook is depleted in late July to early August and release temperatures increase through August (e.g., maximum daily average release temperature of 20.3 ºC occurred on August 17, 2018); however, monitoring data show that after the beginning of August the thermal regime in the basin is such that releases with higher temperatures actually cool as the water travels to HDD (sun declination is lower, canyon walls shade the stream, and cool evenings predominate). When management of Philbrook flows began in 1998, the outflow from the reservoir increased in response to forecasted heat events and then returned to pre- heat levels to save water. This resulted in a large amount of residual water storage at the end of the holding period, which was then released in September to make room in the reservoir for upcoming winter storms (Exhibit B). The Resource Group has moved away from this short-term response to heat events. The contemporary approach is to release elevated outflow from Philbrook incrementally and hold flow volume consistent until weather conditions or the Resource Group warrants a change in flows. This approach maximizes the use of storage during the holding period and minimizes the amount of residual storage at the end of the holding period. This water management approach creates a hydrograph that resembles stair steps and is referred to informally in this document as stepwise management. Although the Resource Group was transitioning to a stepwise management approach in previous years, 2014 was the first year in which this pattern of management was fully employed (Exhibit B). Since 2014, water management followed a basic framework. When diversion of the WBFR at the HDD does not maintain targeted flow in the Hendricks Canal, outflow from the reservoirs is DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 1.0 Introduction 7 FinalDraft – MayApril 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company increased. Outflow from reservoirs was incrementally increased or decreased (based on predicted weather and hydrologic conditions. If no heat event is predicted and flows remain steady in the canal; releases are held steady until the next heat event is forecasted. Using this strategy, releases are increased so maximum flow is reached during the hottest period of the summer (mid-July to early August). Maximum release is held for a short period and duration, which is based on the amount of water available for the remainder of the holding period. Outflow from the reservoir is then decreased incrementally. The timing, duration, and quantity of flow depends on the balance between heat events, remaining storage availability, and seasonal timing. The Resource Group has concluded that this release pattern is beneficial since it utilizes most of the stored Philbrook water from late June through late July when air and Butte Creek water temperatures are at their highest during the holding period. The stepwise release pattern from Philbrook Reservoir (as described above) was used during the 2014 – 2020 & 2022-2025 holding periods. Releases deviated from this stepwise release pattern in 2021 because of limited flows and water availability. PG&E uses a combination of the meteorological forecast and the volume of stored water in Round Valley and Philbrook Reservoirs to determine duration and flow rate released from the reservoirs. This additional information facilitates proactive management of the stored water supply. CDFW provides monitoring data and information about abundance, distribution, and health of fish, and temperatures at Quartz Bowl to help inform and /support Resource Group decisions. Collectively, the Resource Group agrees to a flow proposal based on the information provided. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 8 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 2.0 WATER YEAR TYPE AND OPERATIONS 2.1 Water Year Type for 2026 The 2026 Water Year Type is currently a NormalDry water year type per the definition of the license. The Department of Water Resources (DWR) Bulletin-120 MayApril forecast states that the Feather River Basin April runoff into Oroville is 47% of historical average. Exhibit C lists historical runoff forecasts and water year types since 1998. 2.2 Reservoir Operations for 2026 In the late summer and early fall of 2023, PG&E completed a geotechnical investigation on the spillway at Round Valley Reservoir in support of a recommendation from the 2015 FERC Part 12D Dam Safety Inspection. To mitigate risks identified with the data collected during the 2023 Round Valley Reservoir Geotechnical Investigation, PG&E implemented an internal justification for continued operation (JCO) limit of 5 feet below spill crest on Round Valley Reservoir Elevation. This limit reduces the maximum useable water storage from 1187 acre- feet to 739 acre- feet. The Round Valley low-level outlet (LLO) was closed on April 1, 2026, and then reopened on April 21, 2026, to maintain compliance with PG&E’s internal JCO threshold as mentioned above. The Philbrook LLO is scheduled to continue releasing MIF (2 cfs) unless the temporary flow modification discussed in Section 2.4 is approved, in which case PG&E will follow the amended MIF. PG&E will keep the Resources Agencies informed regarding LLO operations at both reservoirs In 2025, PG&E completed a seismic stability analysis for Philbrook Dam and filed the results of the seismic stability and associated JCO with FERC on February 25, 2025. The seismic stability study indicated unsatisfactory performance of the dam under the seismic loading scenarios DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 9 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company considered when the reservoir is at its normal maximum water surface elevation (NMWSE) of 5,552.5 feet (National Geodetic Vertical Datum of 1929 [NGVD29]), which equates to an operational gage height of 60 feet. Considering these results, the risk of post-seismic deformation has the potential downstream consequence of uncontrolled release of the reservoir. A JCO threshold has been established at Philbrook as an interim risk reduction measure (IRRM) until a long-term solution has been selected and implemented. PG&E will manage the Philbrook Reservoir at a target elevation of 5,542.7 feet NGVD29 (50.2’operational gage height), which is 9.8 feet below the NMWSE and corresponds to a decrease of approximately 1,560 acre-feet of its storage capacity. As a result of the JCO, the spillway radial gate will not be used, and no flashboards will be installed in 2026. Reservoir operation for the holding period is as follows: 1. Releases from Round Valley Reservoir will begin when there is adequate capacity in the Hendricks Canal. The receiving capacity of the Henrick Canal is generally dependent upon water year type and the timing of snowmelt. Due to the elevation restriction required by the JCO, PG&E will only be able to store and use approximately 739 acre-feet of water from Round Valley Reservoir. As of April 17, 2026, Round Valley Reservoir had reached the 739-acre foot threshold. Releases will begin sometime from mid-May to late June. PG&E will notify the Resource Agencies when water releases commence from Round Valley Reservoir. 2. As Round Valley Reservoir nears its minimum elevation, PG&E will consult with the Resource Agencies to determine when releases from Philbrook Reservoir should be increased to avoid a drop in canal flows when Round Valley Reservoir is depleted PG&E will closely monitor the drawdown of Round Valley Reservoir as the minimum elevation is approached. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 10 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 3. The Resource Group will determine the initial flow rate released from Philbrook Reservoir which will be different this year than in previous years because of the limitations of Philbrook Reservoir. Factors considered in establishing the flow rate released from Philbrook (release) used include the date upon which releases commence the objective of reserving water for a possible extreme heat event, the level of natural flows, and the objective of maintaining the highest possible flows through the DeSabla Forebay. 4. The stepwise management strategy will be used to release water from Philbrook Reservoir again in 2026. The stepwise management strategy is the preferred strategy; however, the outflow from the reservoir may increase in response to forecasted heat events and then return to pre-heat event levels to save water based on real-time meteorology and water availability. The Resource Group collectively may recommend conserving available water based on real time information and discussion. To take advantage of available water storage and to maximize cooling during the hottest part of the holding period (early-July to late- August), releases from Philbrook Reservoir should be initiated prior to September. The maximum release rate and duration will depend on available water storage. This approach will help promote optimal water temperatures and efficient use of stored water. The Resource Group will need to work cooperatively to balance release flow volume and duration along with water availability. 4. 5. The Resource Group will hold weekly virtual meetings from June to mid-September (as needed) to discuss outflow from the reservoirs. The Resource Group will determine the stepwise increases in outflow (approximately 5 to 10 cfs each) based on predicted heat events. Weekly virtual meetings will also include discussion of weather forecast, reservoir levels, pre-spawning mortality updates (if conducted), water temperatures (as measured at the holding pool “Quartz Bowl”) by CDFW, and proposed outflow from Philbrook Reservoir. In discussing flow changes to the reservoirs, the Resource Group must consider that the release valves from both reservoirs must be operated manually, and the travel time of the water released from these reservoirs to the Lower Centerville Diversion Dam Formatted: Numbered + Level: 1 + Numbering Style: 1, 2, 3, … + Start at: 1 + Alignment: Left + Aligned at: 0.75" + Indent at: 1" DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 11 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company (LCDD) is approximately 21 to 29 hours. Travel time of operator to the valve locations is approximately 1½ hours during weekdays and may be up to 4 hours on weekends. 6. A flow of 60 cfs is targeted to reduce residence time and minimize heating of water as it moves through the Forebay. The 60 cfs target flow through the DeSabla Forebay will be reviewed during the summer on the weekly calls described above to determine if this rate should be adjusted based on the available releases from Philbrook Reservoir. 7. Water temperature monitoring by PG&E will continue in 2026 at eight stations (Exhibit E), five of which have been used prior to relicensing (since 1998). Installation of temperature loggers will occur in June or as soon thereafter when safe access to the stream channels as possible. Data will be reported to the Resource Agencies during the 2027 Annual Operations Meeting. 8. DWR stream gage BBW (PG&E Gage BW-12) will be used as an indicator of water temperatures in the Project waters that are diverted from the WBFR. BBW data is available on CDEC and provides hourly temperature and flow data. 2.3 Lower Centerville Canal Operations for 2026 LCC has been out of service since 2013 and will remain out of service. 2.4 2026 Minimum Instream Flow Temporary Amendment PG&E submitted a minimum instream flow (MIF) temporary flow modification request with FERC on February 6, 2026. The 2026 request is similar to the previous requests filed with FERC on June 12, 2024, and May 6, 2025. The 2026 flow modification would change MIF requirements to the WBFR below HDD, which is PG&E gage BW-40, from 15 cfs to 7 cfs measured as an average MIF over a 48-hour period. The 2026 flow modification would change the instantaneous DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 12 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company MIF at PG&E gage BW-3 from 2 cfs to a target MIF between 1 cfs and 2 cfs averaged over a 48- hour period. Once approved, the 2026 The temporary flow modification was approved on May 6, 2026 can begin on May 4, 2026, and will end on September 30, 2026. However, the flow changes at BW-3 could begin as early as April 1, 2026, if Philbrook Reservoir has not exceeded 2,116 acre-feet of water storage by that date. The 2026 temporary MIF flow modification will provide flexibility to transfer the maximum amount of water into the Hendricks Canal from the WBFR to increase flow through the DeSabla Forebay to Butte Creek during the hottest part of the summer holding period for CVSRCS in Butte Creek. The JCO at Philbrook Reservoir has lowered the maximum storage capacity of the reservoir, and the temporary MIF flow reductions in the WBFR will allow PG&E to operate like a dry water year. This operating mode will allow PG&E to conserve water resources and maximize water delivery from the WBFR to the Butte Creek during the hottest parts of the summer. This will help maintain the flow through the DeSabla Forebay above 60 cfs to help decrease water residence in the Forebay and minimize heating. During the 2026 CVSRCS holding period, this amendment will allow PG&E greater flexibility to operate around the MIFs while staying compliant during short- lived drops in instream flow readings. In addition, the flow modification at BW-40 will maximize the delivery of flow released from Philbrook to Butte Creek instead of being used to buffer flow to meet instantaneous MIF. 2.5 Contingency for Extreme Heat Event During the Holding Period In anticipation of a possible high ambient air temperature event, the following actions will be taken: 1. Ambient air temperature conditions are a significant factor in determining actual water temperatures in Butte Creek. Starting on June 1 or at such time as the Resource Group determines, PG&E will prepare a weather forecast for the Project area by noon each Monday and Thursday. The weather forecast will be based on information from USFS weather stations at Cohasset and Chester. PG&E will provide an email copy of the forecast to the Resource DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 13 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Agencies. If air temperatures of more than 105ºF for two or more days during the next seven- day period are forecasted at the Cohasset weather station, with the potential for compression heating at higher elevations as confirmed by data from the Chester location, PG&E will send an email to each Resource Agency representative identified in paragraph 4 below advising them that an extreme heat event is forecasted. If the next forecast confirms that an extreme heat event has started or is imminent within the next two days and is expected to continue for over two days, PG&E will send a second email or phone to one of the individuals at each Resource Agency identified in paragraph 4 to discuss actions to be taken. If personal contact cannot be made and PG&E still believes action needs to be taken, it will initiate efforts to modify Project operation as discussed in paragraphs 2–4 below. If action is taken, PG&E will send a third email or phone the Resource Agencies and explain the actions taken. 2. PG&E will coordinate weekly conference calls with the Resource Agencies during the CVSRC holding period. Increased call frequencies will be conducted as requested and agreed upon by the Resource Group. These conference calls are usually conducted from early June through mid-September (as needed). During these conference calls the Resource Group will discuss the results of pre-spawning mortality surveys (if provided by CDFW or NMFS), meteorological forecasts, water temperatures recorded by CDFW at Quartz Bowl, and flows and storage in Philbrook Reservoir. 3. The actual amount of water released from Philbrook Reservoir during a confirmed extreme heat event will depend on PG&E’s assessment of existing conditions and recommendations received from the Resource Agencies in response to the emails. 4. The individuals to whom PG&E will send e-mails under this section are: a. Tracy McReynolds (CDFW) – Tracy.McReynolds@wildlife.ca.gov, (530) 333-7746 b. Grant Henley (CDFW)- Grantton.Henley@wildlife.ca.gov, (916) 272-4152 c. Anna Allison (CDFW) – Anna.allison@wildlife.ca.gov, (916) 272-4373 d. Beth Lawson (CDFW) – Beth.Lawson@wildlife.ca.gov, (916) 358-2875 DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 14 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company e. Ellen Roots (NOAA Fisheries) – ellen.roots@noaa.gov, (916) 930-3722 f. Yvette Redler-Medina (NOAA Fisheries) - yvette.redler-medina@noaa.gov g. Cathy Marcinkevage (NOAA Fisheries) - cathy.marcinkevage@noaa.gov h. Kurt Sable (USFS)– kurt.sable@usda.gov, 530-616-1823 i. Eric Bradbury (SWRCB) – Eric.Bradbury@waterboards.ca.gov, (916) 327-9401 j. Stephanie Millsap (USFWS) - Stephanie_Millsap@fws.gov, (916) 930-2658 k. Brittany Reaves (USFWS) - brittany_reaves@fws.gov, (530) 365-7150 2.6 Spawning Flows in Butte Creek As in previous years, it is best to reduce flow from the WBFR watershed during the fall so that redds in Butte Creek are not at risk of being dewatered if an emergency outage occurs on the Hendricks. In the past, flows from the WBFR were decreased around mid-September when CVSRCS are expected to begin spawning, mean daily temperature decreases naturally, and canal use has less of a cooling effect on water temperature in Butte Creek. Decreasing flows mid- September ensures that fish spawn and rear in the natural flows of Butte Creek, reducing the potential for redd dewatering. Additionally, this decreases the risk of significant flow reduction in Butte Creek in the case of an emergency canal outage. 2.7 Scheduled and Emergency Maintenance and Operations 1. Maintenance Outage Scheduling – To minimize the disruption of flows in Butte Creek during times that are sensitive to CVSRCS holding in Butte Creek, PG&E usually plans to take scheduled canal outages as early as possible in the year. This submission includes all planned outages for PG&E owned tunnels, conduits, or penstocks under FERC licenses (Exhibit D). a. On August 10, 2023, an incident occurred at Butte Canal which removed the canal from service through 2024. Butte Canal will remain out of service for 2026. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 15 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 2. Unplanned Outages (2024-2026) - Winter storms, disruption in canal flows caused by slides or fallen trees, unexpected electric transmission system outages, Public Safety Power Shutoffs (PSPS), and other hazardous conditions can disrupt normal Project operation. PG&E shall use its best efforts to minimize impacts that may result from these conditions, including the actions outlined below: 3. Public Safety Power Shutoff (PSPS) - As part of our Community Wildfire Safety Program, PG&E is implementing additional precautionary measures to help reduce the risk of wildfires. For public safety, it may be necessary for us to turn off electricity as a last resort when extreme fire danger conditions are forecasted. This is called a "Public Safety Power Shutoff." See section below for more information on impacts and responses. 4. Unit Separation from Electric Grid - If the electric transmission grid, generating unit, or a critical support system experiences a problem, or in the event of a PSPS, the generating units automatically separate from the grid and the flow of water to the units is directed away from the turbine. At the Toadtown and DeSabla powerhouses, this is done by means of a bypass device that directs the flow through an energy dissipator bypass and allows the water to continue moving at approximately the same flow. PG&E will adjust the automatic bypass opening during the summer to reasonably correspond to the operational flow of the powerhouse. The shift from the generating unit to the bypass facility may result in a minor release of turbidity caused by sediment that may have built- up in the bypass system since its last use. During a unit separation or PSPS event, standby portable generators are deployed to supply power to station batteries that power bypass system controls. During a separation from electric grid, PG&E increases patrol of canals as some remote operation of equipment and some remote monitoring will not be available. In preparation for PSPS events, PG&E staffs additional personnel to remediate any issues that arise during the duration of the event. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 2.0 WY Type and Operations 16 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 5. Winter Operation and Canal Emergencies – Much of the Project’s canal system traverses steep forested lands. During times of high rainfall and/or high winds, slides, rock falls, and fallen trees can damage canals or block flows. To minimize the potential for damage in the event of blockage or failure of a canal or flume, PG&E may reduce canal flows or dewater canals in advance of such weather events. In addition, emergency spill gates are located at several locations that are equipped with devices that can be operated remotely to spill water at various locations along the canals. PG&E has sensors that report canal water level to the operator at the Rock Creek Switching Center. This location is staffed 24 hours a day, 7 days a week, 365 days a year. If a sensor detects an unexpected change in the canal water level, an alarm is sent to alert the operator on duty. The operator will then dispatch personnel to the location to determine if immediate action can or should be taken to remove water from the canal by activating an emergency spill gate. The emergency spill gates are placed at locations where the channel through which the water will travel is generally protected by rocks and boulders. However, turbidity is possible from vegetative or other debris that may have accumulated in the channel since its last use. Spill channels are routinely inspected at the beginning of the winter season and are typically operated once during a winter high flow event to maintain the prescriptive right for the spill channel and keep the release gate clear of material. This operation results in an incremental increase in the turbidity of Butte Creek for a short period of time, which is typically already elevated during high flow events. Operation of the spill channels that may not be well protected and could likely result in turbidity increases, other than the annual winter operation discussed above, will be operated for emergency purposes only. To avoid releasing water into a damaged canal after a storm event, the canal is patrolled on foot prior to restoring flow. 3.0 WATER QUALITY MONITORING PG&E will monitor water temperature at eight seasonal stations during 2026. These are in addition to the real-time, permanent CDEC station BBW (PG&E gage BW-12). Temperature monitoring will generally be conducted between June and September. Results from 2026 will be presented at DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 4.0 Consultation 17 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company the Annual Operations and Management Meeting in 2027. Monitoring locations are identified in Exhibit E. Prior to the start-up of a canal or powerhouse after an outage, which may result in the possible release of turbidity to Butte Creek, PG&E will monitor water quality using two existing continuous monitoring turbidity sensors located in Butte Creek; one sensor is located at the LCDD, the other sensor is on a wing wall of the CVPH tailrace. In the event of a canal failure, spill gate operation or other release that results in a potential increase of turbidity in Butte Creek, PG&E will secure water quality samples to the extent practicable and taking into consideration personnel safety. The monitoring will be conducted using either grab samples collected by PG&E and tested for turbidity or data from the two continuous monitoring turbidity meters (noted above), set to sample every 15 minutes. Sampling locations will generally be immediately upstream of the dam or point of diversion and approximately 300 feet downstream of the point of release or return to surface waters. If the point of release to surface waters is not reasonably accessible by vehicle, PG&E will sample at the nearest downstream location that can be safely and readily accessed. Turbidity data collected during a canal start-up following a long-term outage of greater than 90 days, will be made available to one representative at each of the Resource Agencies identified in Section 2.5, in a timely fashion. Water temperature data will be provided to Resource Agency representatives upon request. 4.0 CONSULTATION On August 21, 1997, the FERC issued an order placing temperature restrictions on releases from PG&E’s storage reservoirs in the upper WBFR watershed. On August 20, 1998, the FERC revised its order to allow for modification of the criteria upon mutual agreement of the NMFS, CDFW and USFWS. Since 1999, this agreement has been accomplished by way of an annual operations plan for these reservoirs. The reservoir operation varies based on water year conditions. Pursuant to FERC’s August 21, 1998 order, this Operations Plan is annually updated and modified as DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan 4.0 Consultation 18 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company appropriate in consultation with the Resource Agencies. The FERC Order requires the licensee to notify FERC within 30 days after reaching agreement on the O&M Plan. PG&E will meet at least annually with the interested Resource Agencies to discuss and review this O&M Plan. In addition, PG&E will continue to provide updates (generally by email) on Project operations and events to at least one representative from each of the individual Resource Agencies identified in Section 2.5. A summary report will be prepared on annual operations and monitoring data, which will include water and air temperatures, reservoir and conveyance operations and actions taken to minimize effects on the CVSRCS. Nothing in this O&M Plan will be construed as modifying any of the terms and conditions of the DeSabla-Centerville license, FERC No. 803, or in any manner limiting the jurisdiction of the FERC. In the event of any conflict between any of the provisions of this O&M Plan and the license, the provisions of the license will control. PG&E will work with the Resource Agencies, and others, as appropriate, to seek ways to promote prudent land management practices by others where such practices may directly or indirectly impact safe, reliable canal operations. Nothing in this O&M Plan will be construed as either PG&E or the Resource Agencies accepting responsibility for conditions or damage that may be the result of the actions, or inactions, of others. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit A 19 Draft– April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company 5.0 REFERENCES PG&E. 2007. DeSabla-Centerville Hydroelectric Project. FERC Project No. 803. License Application. Appendix E6.2.2.3-G Calibration and Scenarios Report. 14 pp. PG&E. 2015. Final Project Operations Plan – 2015. Pacific Gas and Electric Company DeSabla- Centerville Project (FERC No. 803). June 18, 2015 PG&E. 2025. DeSabla-Centerville project (FERC No. 803). Final 2025 Operations and Maintenance Plan. Exhibit A. Map of Project Area DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit B 20 Draft - April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit B. Comparison of Philbrook Reservoir Storage Usage The graph shows how the management of release has changed through time. From 1998 to 2013, the release of outflow was based on preserving the cold-water pool by increasing flows before and after meteorological forecasted heat storms. This resulted in peak average releases occurring towards the end of the holding period (Average Release (1998-2013). From 2014 to 2025, flow release was based on providing water in a stepwise pattern throughout the first part of the holding period and is decreased in a stepwise pattern towards the latter half of the holding period as storage decreases. This management strategy maximizes outflow during the peak summer period when the flow is most effective at temperature mitigation in downstream reaches (Average Release (2014-2025). A variation of this management strategy occurred in 2021 when the Resource Group managed flows with limited storage during an extremely dry year. 0 10 20 30 40 50 60 6/1 6/9 6/17 6/25 7/3 7/11 7/19 7/27 8/4 8/12 8/20 8/28 9/5 9/13 9/21 9/29 Re l e a s e F l o w ( c f s ) Release Range (1998 - 2013)Release Range (2014-2025) Average Release (1998 - 2013)Average Release (2014-2025) Modified release regime: Weighted toward peak period of summer temperatures when available DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit C 21 Draft- April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit C. Historical Runoff Forecast and Water Year Type Since 1998 Water Year Forecast Year Type 1998 10% April 2026) % Runoff Forecasts are the published May 1 Bulletin 120 forecast of April – July unimpaired runoff into Oroville Reservoir computed by the State of California at that time. Water Year Type is “Dry” if the runoff forecast is 50% or less. DeSabla-Centerville Project (FERC Project No. 803) 2026 Operations and Maintenance Plan Exhibit D 22 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit D. 2026 and 2027 Projected Scheduled Maintenance and Outages DESABLA-CENTERVILLE 2026 & 2027 MAINTENANCE AND OUTAGE SCHEDULE LOCATION DURING OUTAGE STRUCTURE Start Date End Date TOADTOWN Canal Canal Annual Canal 3/30/2026 5/04/2026 HENDRICKS CANAL Canal Annual Canal 3/30/2025 5/04/2026 TOADTOWN Canal Canal Annual Canal 3/29/2027 4/25/2027 HENDRICKS CANAL Canal Annual Canal 3/29/2027 4/25/2027 DeSabla-Centerville Project (FERC Project No. 803) 2025 Operations and Maintenance Plan Exhibit E 23 Draft – April 2026 Hydroelectric Project License Compliance ©2026, Pacific Gas and Electric Company Exhibit E. 2026 PG&E Seasonal Monitoring locations 1. Philbrook Creek (PG&E Gage BW-3) at release * (Temperature and Flow) 2. WBFR at Hendricks Head Dam (PG&E Gage BW-40) * (Temperature and Flow) 3. BW-12 Gage Station reported to CDEC (BBW)* (Temperature and Flow) 4. Total canal inflow to DeSabla Forebay * (Temperature and Flow) 5. Butte Creek above DeSabla Powerhouse 6. DeSabla Powerhouse tailrace * (Temperature and Flow) 7. Butte Creek at LCDD * (Temperature, Turbidity, and Flow) 8. Butte Creek at Centerville Powerhouse (Temperature and Turbidity)