HomeMy WebLinkAbout5.3.22 Board Correspondence - FW_ Dam Safety Compliance Report submitted in FERC P-619-000 by Pacific Gas and Electric Company,et al. (3)
From:Paulsen, Shaina
To:BOS
Subject:Board Correspondence - FW: Dam Safety Compliance Report submitted in FERC P-619-000 by Pacific Gas and
Electric Company,et al.
Date:Tuesday, May 3, 2022 12:56:43 PM
Please see Board Correspondence below.
Shaina Paulsen
Associate Clerk of The Board
Butte County Administration
25 County Center Drive, Suite 200, Oroville, CA 95965
T: 530.552.3304 | F: 530.538.7120
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Sent: Tuesday, May 3, 2022 12:45 PM
Subject: Dam Safety Compliance Report submitted in FERC P-619-000 by Pacific Gas and Electric Company,et al.
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On 5/3/2022, the following Filing was submitted to the Federal Energy Regulatory Commission (FERC),
Washington D.C.:
Filer: Pacific Gas and Electric Company
PGE (as Agent)
Docket(s): P-619-000
Lead Applicant: Pacific Gas and Electric Company
Filing Type: Dam Safety Compliance Report
Description: Pacific Gas and Electric Company submits Plans and Schedules to Address Recommendations re
Seismic Evaluations for Bucks Creek Hydroelectric Project under P-619.
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Mailing Address:
Mail Code N11D
P.O. Box 770000
San Francisco, CA 94177
May 3, 2022
Via Electronic Submittal (E-File)
Frank L. Blackett, P.E., Regional Engineer
Federal Energy Regulatory Commission
Division of Dam Safety and Inspections
San Francisco Regional Office
100 First Street, Suite 2300
San Francisco, CA 94105-3084
RE: Bucks Creek Hydroelectric Project, FERC No. 619-CA
Plans and Schedules Related to Seismic Evaluations
ENCLOSURE CONTAINS CUI//CEII DO NOT RELEASE
Dear Frank L. Blackett:
address recommendations and Federal Energy Regulatory Commission (FERC) review
comments pertaining to seismic-related studies of dams and appurtenant structures that are
part of Bucks Creek Hydroelectric Project, FERC No. 619. The studies are the subject
of follow-up actions from a variety of sources, including 5-year Part 12D safety inspections,
focused spillway assessments, 10-year radial gate inspections, and associated FERC
comments. For reference the following dams are covered under this submittal:
Bucks Storage Dam, NATDAM No. CA00332
Bucks Diversion Dam, NATDAM No. CA00331
Grizzly Forebay Dam, NATDAM No. CA00333
Over the past several years, PG&E has been engaged in an updated assessment of seismic
ground-motion hazards within its hydroelectric system, which encompasses 22 FERC-licensed
projects in northern and central California. While the assessment was in progress, PG&E
deferred some seismic-related studies at its dams, along with corresponding updates to the
finalized. The deferred studies depend on updated seismic input parameters to evaluate
seismic performance of the dams and their appurtenant structures or, in some cases,
determination of whether further investigation or analysis is necessary.
PG&E recently completed its updated seismic hazard assessment, the results of which are
presented in a report titled Deterministic Seismic Hazard Results Report (DSHR), PG&E
System-Wide Hydro Risk Project, prepared by PG&E and dated December 2021. PG&E
submitted the report to FERC in a letter dated December 20, 2021. In a subsequent filing,
Frank L. Blackett, P.E., Regional Engineer
May 3, 2022
Page 2
dated April 15, 2022, PG&E submitted a comparison of the 2021 seismic hazard estimates
with those of earlier studies.
After completing the 2021 DSHR, PG&E performed an initial screening to examine whether the
existing seismic analyses of record for its dams remain valid or new/revised analyses are
needed, based on the updated seismic hazard estimates. Results of the screening exercise
indicate that estimated deterministic ground motions presented in the 2021 DSHR are in many
cases higher than those assumed for prior seismic analyses. Therefore, new or revised
analyses are needed to evaluate performance of the dams and their appurtenant structures
under the increased seismic loading.
To manage the scope of the seismic reevaluation effort, PG&E established a program to
prioritize and complete the updated seismic analyses over a period of approximately 5 years.
Considerations for prioritizing and scheduling the analyses include the hazard classification of
the dam, relative increase in estimated ground motions over previously assumed values,
estimated return periods of the deterministic ground motions, timing of upcoming 5-year Part
-progress seismic analyses
were not considered as part of the prioritization effort and will remain on their current
schedules for completion using updated seismic hazard parameters.
PG&E also reviewed open follow-up actions associated with the deferred seismic studies and
developed plans and schedules to complete the studies using results of the 2021 seismic
reevaluation program, are presented in the enclosed summary tables (Enclosure 1). The
summary tables, one for each dam, identify the original sources of the follow-up actions, the
to resolve the follow-up actions. Follow-up actions are organized into three categories: (1)
near-term deliverables (2022 through 2024), (2) long-term deliverables (2025 through 2027),
and (3) STID updates.
safety engineer, Ben Fontana, at (530) 762-9459. For general questions, please contact
Matthew Joseph, at (530) 889-3276.
Sincerely,
Robert O. Ellis, P.E., G.E.
Deputy Chief Dam Safety Engineer
Enclosure: CUI//CEII DO NOT RELEASE
1. Plans and Schedules Related to Seismic Evaluations