Gilroy City Council
July 29, 2024

agencies to carry out their responsibilities under the plan.

NOW, THEREFORE, BE IT RESOLVED that the City Council of the City of Gilroy adopts the Santa Clara County Multi-Jurisdictional Hazard Mitigation Plan Volume 1 and 2 as an official plan; and
BE IT FURTHER RESOLVED that the City of Gilroy adopts the Santa Clara County Multi-Jurisdictional Hazard Mitigation Plan Volume 1 and 2 by reference into the safety, or potential hazards element of the general plan in accordance with the requirements of AB 2140; and
BE IT FURTHER RESOLVED that the City of Gilroy will submit this adoption resolution to the California Office of Emergency Services and FEMA officials to enable the plan’s final approval in accordance with the requirement of AB 2140.

PASSED AND ADOPTED this 29th day of July, 2024 by the following roll call vote:

AYES: COUNCIL MEMBERS:

NOES: COUNCIL MEMBERS:

ABSENT: COUNCIL MEMBERS:

APPROVED:

______________________________
Marie Blankley, Mayor
ATTEST:

Beth Minor, Interim City Clerk

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Resolution No. 2024-XX
Adoption of the Multi-Jurisdictional Hazard Mitigation Plan City Council Regular Meeting | July 29, 2024

CERTIFICATE OF THE CLERK
I, BETH MINOR, Interim City Clerk of the City of Gilroy, do hereby certify that the attached Resolution No. 2024-XX is an original resolution, or true and correct copy of a City Resolution, duly adopted by the Council of the City of Gilroy at a Regular Meeting of said held on Council held Monday, July 29, 2024, with a quorum present.

IN WITNESS WHEREOF, I have hereunto set my hand and affixed the Official Seal of the City of Gilroy this Date.
____________________________________
Beth Minor
Interim City Clerk of the City of Gilroy
(Seal)

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SANTA CLARA COUNTY

MULTIJURISDICTIONAL

HAZARD MITIGATION
PLAN
Volume 1: Base Plan
2023
Office of Emergency Management
County of Santa Clara
55 W. Younger Ave., San Jose, CA

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Santa Clara County Multijurisdictional Hazard Mit igation Plan—DRAFT This work was sponsored by the Santa Clara County Office of Emergency Management.

The research was conducted by IEM, incorporating data provided by Santa Clara County Office of Emergency Management.

IEM is a global consulting house for safety, security, strategic performance, and sustainability. We combine objective, scientific analysis with a broad spectrum of experience to provide practical, effective solutions for public and private sectors. IEM’s publications do not necessarily reflect the opinions of its research clients and sponsors.
is a registered trademark.
© Copyright 2023 IEM
IEM documents are protected under copyright law.
http://www.iem.com
(800) 977-8191

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acknowledgements i
Acknowledgements
County of Santa Clara Core Planning Team
 Dr. Parastou Najaf, Santa Clara County Office of Emergency Management, Senior Emergency Manager – Mitigation/Recovery
 Magdalena Sta Maria, Santa Clara County Office of Sustainability, Sustainability Analyst  Samuel Gutierrez, Santa Clara County Department of Planning and Development, Principal Planner
Planning Partners
 Michael Alvarez, County of Santa Clara, Principal Development Services Engineer/ Floodplain Administrator
 Dan Livingston, City of Campbell, Captain of Support Services Division, Police Department  Ron Taormina, City of Campbell, Acting Superintendent  Bob Lennen, City of Campbell, Building Official
 Meredith Albert, City of Cupertino, Emergency Management Analyst  Thomas Chin, City of Cupertino, Emergency Manager
 Andre Duurvoort, City of Cupertino, Sustainability Manager  Susan Michael, City of Cupertino, Capital Improvement Program Manager  Jimmy Tan, City of Cupertino, Assistant Director of Public Works  Chad Mosley, City of Cupertino, Acting Director of Public Works  Jennifer Chu, City of Cupertino, Senior Civil Engineer/City of Public Works  Esther Kwon, City of Cupertino, Public Information Officer  Andrew Young, City of Gilroy, Emergency Services and Volunteer Coordinator  Sharon Goei, City of Gilroy, Community Development Director  Daryl Jordan, City of Gilroy, Public Works Director/Floodplain Administrator  Kathryn Krauss, City of Los Altos, Captain of Operations, Police Department  Vency Woo, City of Los Altos, Management Analyst
 Irene Silipin, City of Los Altos, HR Manager
 Marisa Lee, City of Los Altos, Transportation Services Manager  Veronica Tinoco, City of Los Altos, Building Official  Stephanie Williams, City of Los Altos, Planning Services Manager/ Floodplain Manager  Franklin Wong, City of Los Altos, Public Works. CIP Manager

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acknowledgements ii
 Vivian Chu, City of Los Altos, Finance Manager
 Manny Hernandez, City of Los Altos, Parks and Rec Director  Jon Maginot, City of Los Altos, Assistant City Manager  Angela Averiett, City of Los Altos, Police Chief
 June DU, City of Los Altos, Finance Director
 Sonia Lee, City of Los Altos, Public Information Officer  Nick Zorner, City of Los Altos, Development Services Director  Brian Glass, City of Los Altos, Assistant Fire Chief
 Ann Hepenstal, Town of Los Altos Hills, Emergency Management Consultant  Woojae Kim, Town of Los Altos Hills, Public Works Director/ Floodplain Administrator  John Chau, Town of Los Altos Hills, Associate Engineer  Elaine Ling, Town of Los Altos Hills, Senior Planner
 Jeremy Loh, Town of Los Altos Hills, Associate Planner  Jonathan Fox, Town of Los Altos Hills, Assistant Planner  Gerry Igtanloc, Town of Los Altos Hills, Building Technician  Cody Einfalt, Town of Los Altos Hills, Management Analyst II/ Interim Assistant to the City Manager
 Nicolle Burnham, Town of Los Gatos, Director of Parks and Public Works  Holly Young, Town of Los Gatos, Senior Analyst
 Toni-Lynn Charlop, City of Milpitas, Office of Emergency Management Coordinator  Elaine Marshal, City of Milpitas, Deputy Director, Public Works  Jay Lee, City of Milpitas, Principal Planner
 Bill Tott, City of Milpitas, Building Official
 Arthur Belton, City of Milpitas, Fire Marshal
 Michael Silveira, City of Milpitas, CIP Manger
 Samantha Vergara, City of Milpitas, Special Projects/Drought & Climate Change  Brian Petrovic, City of Milpitas, Floodplain Administrator  Jennifer Ponce, City of Morgan Hill, Emergency Services Coordinator  Hilary Holeman, City of Morgan Hill, Administrative Analyst  Scott Creer, City of Morgan Hill, Floodplain Administrator  Robert Maitland, City of Mountain View, Fire Department Public Information Officer, Office of Emergency Services Coordinator
 Eric Anderson, City of Mountain View, Advanced Planning Manager  Nena Bizjak, City of Mountain View, Chief Building Official  Renee Gunn, City of Mountain View, Associate Civil Engineer/ Floodplain Administrator

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acknowledgements iii
 Nathaniel Rainey, Emergency Services Coordinator, Office of Emergency Services  Ray Riordan, City of San Jose, Director of Emergency Management  Jay McAmis, City of San José, Deputy Director of Emergency Management  Mariana Chavez-Vazquez, City of San Jose, Assistant Director of Environmental Services Department
 Rajani Nair, City of San Jose, Deputy Director of Environmental Services Department  Jennifer Brown, City of San Jose, Division Manager of Environment Services Department  Jennie Loft, City of San Jose, Public Information Manager of Environmental Services Department  Kat Estrada, City of San Jose, Program Manager of Environmental Services Department  Sean Monlux, City of San Jose, Analyst II
 Kendra Yarn, City of San Jose, Program Manager/ Parks Recreation & Neighborhood Services  Torie O’Reilly, City of San Jose, Division Manager/Parks  Olympia Williams, City of San Jose, Division Manager/ Beautify  Sara Sellers, City of San Jose, Acting Deputy Director  Paul Lim, City of San Jose, Emergency Response program Manager  Steve Choy, City of San Jose, Acting Division Manager/ Division Manager Capital Improvement Project Program Manager
 Samuel Young, City of San Jose, Division Manager Development Services  Norman Mascarinas, City of San Jose, principal Engineer Transportation and Hydraulics Services  Sanhita Ghosal, City of San Jose, Planner IV/Supervising Planner/ Floodplain Administrator  Jennifer Guzman, City of Santa Clara, Emergency Management Analyst  Gary Welling, City of Santa Clara, Director of Water and Sewer Services  Shilpa Mehta, City of Santa Clara, Assistant Director of Water and Sewer Utilities  Craig Mobeck, City of Santa Clara, Director of Public Works  Michael Liw, City of Santa Clara, Assistant Director of Public Works  Falguni Armin, City of Santa Clara, Principal Engineer  Manuel Pineda, City of Santa Clara, Chief Electric Utility Officer  Kevin Kolnowski, City of Santa Clara, Electric Utility Chief Operating Officer  Andrew Crabtree, City of Santa Clara, Director of Community Development/ Floodplain Manager  John Davidson, City of Santa Clara, Principal Planner  Armand Lobao, City of Santa Clara, Building Official
 Ruben Torres, City of Santa Clara, Fire Chief
 John Madden, City of Santa Clara, Deputy Fire Chief
 Jeremy Ray, City of Santa Clara, Deputy Fire Chief
 Dennis Yee, City of Santa Clara, Fire Captain

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acknowledgements iv
 Wahid Kazem, City of Santa Clara, Assistant Police Chief  Cuong Phan, City of Santa Clara, Police Lieutenant
 Michelle Templeton, City of Santa Clara, Sustainability Manager  David Knight, City of Santa Clara, Communication Management Analyst  Aaron Yuma, City of Saratoga, Building Official
 Neil Valenzuela, City of Saratoga, West Valley Patrol Commander  David Dorcich, City of Saratoga, Associate Civil Engineer. Floodplain Administrator  Jason Falarski, City of Saratoga, Deputy Chief
 Thomas Scott, City of Saratoga, Facilities Manager
 Crystal Bothelio, City of Saratoga, Assistant City Manager  Trudi Ryan, City of Sunnyvale, Director, Community Development  Ramana Chinnakotla, City of Sunnyvale, Director, Environmental Services  Sean Smith, City of Sunnyvale, Street Operations Manager  Mary Jeyaprakask, City of Sunnyvale, Senior Planner
 Suzanne Park, City of Sunnyvale, Chief Building Official  Daniel Moskowitz, City of Sunnyvale, Lieutenant, Office of Emergency Services, Department of Public Safety
 Louay Toma, Santa Clara County Fire Department, Senior Program Specialist  Dennis Lollie, Santa Clara County Fire Department, Deputy Chief  Juan Ledesma, Santa Clara Valley Water District, Program Administrator Supervisor, Office of Emergency Services
 Andres Acevedo, Santa Clara Valley Water District, Senior Management Analyst  Jack XU, Santa Clara Valley Water District, Senior Engineer/ Hydra, Hydro & Geo  Liang XU, Santa Clara Valley Water District, Hydro, Hydra & Geomorph Manager  Jay Lee, Santa Clara Valley Water District, Watershed Field Ops Manager  Devin Mody, Santa Clara Valley Water District, Ops & Maintenance Engineer Support Manager  Greg Meamber, Santa Clara Valley Water District, Senior Engineer/ Operations & Maintenance  Nina Merrill, Santa Clara Valley Water District, Senior Water Resources Specialist  Steven Wu, Santa Clara Valley Water District, Senior Engineer/ Geotechnical  Brandon Stewart, Midpeninsula Regional Open Space District, Lands and Facilities Department Manager
 Korrine Skinner, Midpeninsula Regional Open Space District, Public Affairs Manager  Matt Anderson, MidPeninsula Regional Open Space District, Chief Ranger and Visitor Services Manager
 Hillary Stevenson, Midpeninsula Regional Open Space District, General Counsel  Jane Mark, Midpeninsula Regional Open Space District, Planning Manager

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acknowledgements v
 Jason Lin, Midpeninsula Regional Open Space District, Engineering and Construction Manager  Deborah Hirst, Midpeninsula Regional Open Space District, Grants Program Manager  Brad Bartholomew, IEM, Project Manager
 Jessica Mason, IEM, Leader Planner
 Kate Smith, IEM, GIS/Hazus Specialist
 Carron Day, IEM, Planner
 Casey Garnett, IEM, Planner
 Krystian Murray, IEM, Planner
 Alayna Payne, IEM, Planner
 Sabrina Lunsford, IEM, Planner

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Acronyms vi
Acronyms
AB Assembly Bill
ABAG Association of Bay Area Governments
ADA Americans with Disabilities Act
AELR Annualized Earthquake Loss Ratio
AFN Access and Functional Needs
APA Approvable-Pending-Adoption
APG California Climate Adaptation Planning Guide
ARES Amateur Radio Emergency Service
BAWSCA Bay Area Water Supply Conservation Agency
BRIC Building Resilient Infrastructure and Communities
CAL FIRE California Department of Forestry and Fire Protection Cal OES California Office of Emergency Services
CALGreen California Green Building Standards Code
Caltrans California Department of Transportation
CARAS Community Agency for Resources, Advocacy, and Services CCR California Code of Regulations
CDBG-DR Urban Development Community Development Block Grant Disaster Recovery CDBG-MIT Community Development Block Grant Mitigation
CDC U.S. Centers for Disease Control and Prevention
CEQ Council on Environmental Quality
CEQA California Environmental Quality Act
CERCLA California Emergency Planning and Community Right-to-Know Act CERT Community Emergency Response Team
CFR Code of Federal Regulations
CGS California Geological Survey
C-MIST Communication, Maintaining Health, Independence, Safety, Support Services, and SelfDetermination, and Transportation COOP Continuity of Operations Plan
COVID-19 Coronavirus Disease of 2019
CPAD California Protected Area Database
CPUC California Public Utilities Commission
CRS Community Rating System
CSZ Cascadia Subduction Zone
CWA Clean Water Act
CWPP Community Wildfire Protection Plan
CWSRF Clean Water State Revolving Fund
CZM Coastal Zone Management
DFIRM Digital Flood Insurance Rate Map
DHS U.S. Department of Homeland Security
DMA Disaster Mitigation Act of 2000
DR Disaster Declaration
DSOD Division of Dam Safety

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DSOD Division of Safety of Dams
DWR Department of Water Resources
DWR Department of Water Resources
EAP Emergency Action Plan
EBB Earthquake Brace + Bolt Program
EIR Environmental Impact Report
EM Emergency Declaration
EMAP Emergency Management Accreditation Program
EOC Emergency Operations Center
EPA Environmental Protection Agency
ESA Endangered Species Act
FBI Federal Bureau of Investigation
FEMA Federal Emergency Management Agency
FERC Federal Energy Regulatory Commission
FHSZ Fire Hazard Severity Zones
FIRM Flood Insurance Rate Map
FIS Flood Insurance Study
FMA Flood Mitigation Assistance
FMAG Fire Mitigation Assistance Grants
FRMP Flood Risk Management Program
GIS Geographic Information Systems
HHPD High Hazard Potential Dam
HMGP Hazard Mitigation Grant Program
HMGP-PF Hazard Mitigation Grant Program Post Fire
HMP Hazard Mitigation Plan
HUD U.S. Department of Housing and Urban Development
Hwy Highway
IBC International Building Code
ICARP Integrated Climate Adaptation and Resiliency Program IED Improvised Explosive Device
IEM Innovative Emergency Management
IID Improved Incendiary Device
IPCC Intergovernmental Panel on Climate Change
IT Information Technology
JTTF Joint Terrorism Task Force
LEWS Landslide Early Warning Systems
LOMA Letter of Map Amendment
LOMR Letters of Map Revision
MJHMP Multijurisdictional Hazard Mitigation Plan
MMI Modified Mercalli Intensity Scale
NASA National Aeronautics and Space Administration
NBS Nature Based Solutions
NCRIC Northern California Regional Intelligence Center
NEHRP National Earthquake Hazard Reduction Program
NEPA National Environmental Policy Act
NFIP National Flood Insurance Program
NGO Non-Governmental Organization
NHD Natural Hazard Disclosure
NID National Inventory of Dams

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NIMS National Incident Management System
NOAA National Oceanic and Atmospheric Administration
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conversation Services
NSI National Structure Inventory
NTHMP National Tsunami Hazard Mitigation Program
NWS National Weather Service
OA Operational Area
OEM Office of Emergency Management
PAL Provisionally Accredited Levee
PCA Project Cooperation Agreement
PDM Pre-Disaster Hazard Mitigation
PG&E Pacific Gas and Electric
PGA Peak Ground Acceleration
PHMSA Pipeline and Hazardous Materials Safety Administration PTSD Post Traumatic Stress Disorder
Risk MAP Risk Mapping, Assessment and Planning
SAFRR Science Application for Risk Reduction
SAR Suspicious Activity Report
SCCFD Santa Clara County Fire Department
SCCOEM Santa Clara County Office of Emergency Management SCVWD Santa Clara Valley Water District
SEMS Standardized Emergency Management System
SFHA Special Flood Hazard Area
SHMO State Hazard Mitigation Officer
SHMP State Hazard Mitigation Plan
SR State Route
SRA State Responsibility Area
STORM Safeguarding Tomorrow through Ongoing Risk Mitigation SVACA Silicon Valley Animal Control Authority
TRI Toxic Release Inventory
USACE U.S. Army Corps of Engineers
USDA U.S. Department of Agriculture
USDM U.S. Drought Monitor
USFWS U.S. Fish and Wildlife Service
USGS U.S. Geological Survey
VHF Viral Hemorrhagic Fever
VTA Santa Clara Valley Transportation Authority
WHO World Health Organization
WNV West Nile Virus
WUI Wildland Urban Interface
WVFPO Watershed and Flood Prevention Operations Program

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Executive Summary ix
Executive Summary
Hazard Mitigation Planning Background
Hazard mitigation involves the use of long-term and short-term policies, programs, projects, and other activities to alleviate the death, injury, and property damage that can result from a disaster. Santa Clara County and a partnership of local governments and special districts within the county have developed a multijurisdictional hazard mitigation plan to reduce risks from natural disasters in the Santa Clara County Operational Area (OA)—defined as the unincorporated county and incorporated jurisdictions within the geographical boundaries of the county. The plan reaffirms the planning partners commitment to implementing cost-effective, environmentally sound, technically feasible mitigation actions. It also complies with federal and state hazard mitigation planning requirements to establish eligibility for funding under Federal Emergency Management Agency (FEMA) grant programs.

The whole community of the Santa Clara County OA—including individual and families, businesses, community and nonprofit organizations, schools and academia, and all levels of government—is the ultimate beneficiary of this MJHMP. Implementing the plan will reduce risk for those who live in, work in, and visit the OA. The plan provides a viable planning framework for natural hazards of concern for the area. Participation in development of the plan by key stakeholders helped ensure outcomes will be mutually beneficial. The resources and background information in the plan are applicable across the OA, and the plan’s goals and recommendations can lay the groundwork for the development and implementation of local mitigation activities and partnerships for years to come.

History of Regional Planning Efforts for Hazard Mitigation The Association of Bay Area Governments (ABAG) provides communities in the San Francisco Bay area with planning and research resources related to land use, housing, environmental and water resource protection, disaster resilience, energy efficiency, hazardous waste mitigation, risk management and financial services. In 2004, ABAG led a regional effort to address hazard mitigation planning for Bay Area jurisdictions. ABAG’s regional template was used by numerous counties and cities to meet federal hazard mitigation planning requirements. The ABAG process enabled individual planning processes to meet local government needs, while pooling resources and eliminating redundant planning efforts.

In 2010, ABAG conducted its second regional planning effort. Municipalities that used the 2010 updated ABAG tools to meet federal hazard mitigation planning requirements included the County of Santa Clara and the cities of Campbell, Cupertino, Gilroy, Los Altos, Los Altos Hills, Los Gatos, Milpitas, Monte Sereno, Morgan Hill, Mountain View, Palo Alto, San José, Santa Clara, Saratoga, and Sunnyvale. ABAG discontinued its full support of the regional planning concept in 2015, so jurisdictions that were covered under the regional plan must initiate individual or reformed multijurisdictional planning efforts to continue to comply with federal mitigation planning requirements.

In 2016, Santa Clara County, the Santa Clara County Fire Department, and all incorporated cities in Santa Clara County teamed together to prepare an updated Multijurisdictional Hazard Mitigation Plan tailored to the local needs and capabilities of the Santa Clara County Operational Area. The planning partnership developed a new plan from scratch, using lessons learned from the earlier ABAG planning efforts. Compared to previous planning efforts, the plan focused on more localized concerns, newly available data and tools to enhance the risk assessment, considering FEMA’s Community Rating System (CRS) for flood insurance, and identifying cost-effective actions.

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The 2023 Santa Clara County Operational Area Planning Effort In 2022, Santa Clara County reconvened the planning team and a consultant was hired to support the planning process. This allowed participants to focus on ongoing hazard events including multiple atmospheric rivers and a winter storm while ensuring that mitigation planning effort continued moving forward. Additional ways the 2023 plan differs from previous plans includes:
 The risk assessment includes further considerations of emerging hazards, like the impact of wildfire smoke, which have recently threatened the OA.
 A concentrated effort to ensure plan integration between the County Community Wildfire Protection Plan and County Safety Element of the County General Plan updates as well as other approved plans.
 The incorporation of the additional special district planning partners of Midpeninsula Regional Open Space District, Santa Clara County Fire Department, and Santa Clara Valley Water District, which are involved in hazard mitigation in the OA.
 The plan was developed in accordance with EMAP standards.  The risk assessment has been formatted to provide information on risk and vulnerability that will allow a measurement of cost-effectiveness.
 Mitigation goals and objectives and criteria for mitigation action item prioritization have been updated to include climate change, resiliency, and benefits to populations that are underserved and/or socially vulnerable.
 The update gave the planning partners an opportunity to engage residents, particularly those who are underserved and/or socially vulnerable and gauge their perception of risk and support for risk reduction through mitigation.
 The update also gave planning partners an opportunity to engage community stakeholders, particularly those that assist underserved and/or socially vulnerable and gauge their perception of risk and support for risk reduction through mitigation.  Climate change has been added as a hazard for the planning area.  Each planning partner has a minimum of one mitigation action per a hazard that can impact them.  Expanded information about planning partner participation and compliance in the National Flood Insurance Program.

Plan Development Approach
Phase 1: Schedule of Work
A Core Planning Team consisting of staff from the Santa Clara County Office of Emergency Management, Office of Sustainability, and Department of Planning and Development, and a contract consultant, Innovative Emergency Management (IEM), was assembled to facilitate the update of this plan.

This team then formed a planning partnership with local governments, special districts, and other County departments within the OA. Planning partners were also requested to identify additional stakeholders, both internal and external to their community or organization, were invited to participate in the planning process. Some of types of stakeholders identified by partners included representatives from academia, nonprofits, businesses, and other agencies involved in Hazard Mitigation like the California Office of Emergency Services (Cal OES). The Core Planning Team oversaw the plan update, compliance with FEMA hazard mitigation planning guidelines, and the plan update schedule. Stakeholders were frequently engaged through meetings, one-on-one calls, and emails including meeting notes to ensure they understood their role in the plan update.

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The plan schedule was updated to reflect the needs of the stakeholders and committing priorities as multiple disaster events occurred during the update process. This phase also included a review of the existing MJHMP, the current and draft California statewide hazard mitigation plan, and other existing programs and resources that support hazard mitigation actions in the OA.

Phase 2: Determine the Planning Area and Resources
The scale of the plan can determine the level of detail that may be included. In this case, the County lead a county-wide planning effort. Planning partners were provided the space to input even more localized data in their sections of the plan as well. New and updated resources and data sources were identified throughout the planning process. FEMA’s Hazus tool for natural hazard analysis was utilized where possible to assess risk and estimated building damage impacts.

Phase 3: Build the Planning Team
The Core Planning Team invited stakeholders to participate in a series of planning meetings on each of the components of the planning process. After each meeting, planning partners had the opportunity to add their input through forms such as Capability Assessment, Risk Assessment and Mitigation Project Worksheet. The planning team update was additionally supported by input from the public. This input was garnered through several collaborative public meetings, a digital survey, and the utilization of social media and a project website.

Phase 4: Create an Outreach Strategy
The opportunity for public participation is an important step of the hazard mitigation planning process. For this plan update, the Core Planning Team developed and implemented a whole community, multi-lingual, in-person, and virtual approach to public outreach. Since the County was already working on updating the County’s Safety Element, which includes different but similar hazard risk and disaster response and recovery considerations, the two planning teams collaborated to share information on this Multijurisdictional Hazard Mitigation Plan (MJHMP). Two in-person listening sessions were held and one virtual town hall meeting was held to inform the public about the Safety Element and MJHMP update and to garner feedback about hazards of concern and levels of preparedness in the community.

The Santa Clara County Community Wildfire Protection Plan (CWPP) was also being updated simultaneously with the MJHMP, and the two project teams collaborated to share information. Four inperson meetings were held to share information about the CWPP and MJHMP and solicit feedback from the public about the plans.

The County and planning partners also requested public participation through a digital survey posted on the Santa Clara County Office of Emergency Management’s website available in English, Spanish, Chinese, Vietnamese, and Tagalog. This survey received almost 600 responses. Finally, the public was provided the opportunity to review and provide input on the draft MJHMP.

Phase 5: Review Community Capabilities
A thorough understanding of community capabilities can help decision makers identify feasible hazard mitigation actions. The planning team evaluated each jurisdiction’s existing authorities, policies, programs, and resources including staff and funding resources. Applicable opportunities to expand upon on and improve these policies and programs were identified in the Mitigation Strategy. The main point of contact for each planning partner successfully engaged and utilized their planning teams as subject matter experts and planning support throughout the MJHMP process.

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Phase 6: Risk Assessment
Risk assessment is the process of measuring the potential loss of life resulting from natural hazards, as well as personal injury, economic injury, and property damage, in order to determine the vulnerability of people, buildings, and infrastructure to natural hazards. The risk assessment provides the scientific basis for mitigation actions. It begins with hazard identification and profiling. Each hazard that may impact the planning area was profiled utilizing the best available data from local, state, and federal resources including other plans, studies, and databases. Each hazard profile includes risk information such as the location, extent, previous occurrences, future probability of each hazard, and estimated cost of potential damage. Furthermore, a vulnerability assessment was incorporated into each profile to show the expected impacts on people, buildings, critical infrastructure, and future development. The role of climate change and potential cascading impacts is also described.

As part of a comprehensive risk assessment, planning partners used a hazard risk index to evaluate the probability of occurrence, potential life impact, property impact, percentage of planning area impacted, and extent for each applicable hazard. The overall hazard risk index results based on an average of partner indices is shown in Table 1. These results show which hazards pose the highest overall risk to the Operational Area.

Table 1: Average Overall Hazard Risk Index Results
Hazard Risk Order Hazard Average Overall Hazard Risk
Index Result
1 Earthquake 2.13
2 Wildfire, wildfire smoke, and air quality 1.71
3 Heavy precipitation, heavy winds,
extreme temperatures

1.45 4 Drought 1.25
5 Climate change, including sea-level rise 1.19
6 Dam and levee failure .83
7 Flood .79
8 Landslide and mass movement .41
9 Tsunami .03
Based on the average overall hazard risk index results from planning partner risk indices:
 The earthquake hazard has the highest risk results, followed by wildfire/smoke/air quality.  The inclement weather, drought, climate change hazards were a moderate risk to the Operational Area.
 The dam failure, flood, and landslide/mass movement hazards were a lower risk to the Operational Area.
 The tsunami hazard poses the lowest risk to the Operational Area, as not all planning partners can be impacted by this hazard due to geographic location.

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Phase 7: Develop a Mitigation Strategy
The Mitigation Strategy is often referred to as the heart of the plan, or the blueprint for breaking the cycle of disaster response and recovery. A risk-based, capabilities-informed mitigation strategy outlines the framework for short-term and long-term community resilience. A guiding principle as well as overarching goals and objectives were established for the Mitigation Strategy. In order to facilitate this important part of the plan update, a Mitigation Projects Working Group was convened. This group was responsible for coming up with suggestions for mitigation actions and reviewing and updating the 2017 Goals and Objectives to align with the changed hazard landscape and the new guidelines. Other plans previously approved by the planning partners were also evaluated for potential mitigation actions. Planning partners then assessed their mitigation actions from the past plan and updated them where needed as well as developed new mitigation actions. These actions were then compiled in their annexes in an action plan which included information on the time, cost, funding source, and lead agency.

Phase 8: Draft Multijurisdictional Hazard Mitigation Plan with Public Input and Maintenance Procedures
The Core Planning Team and Working Group assembled a document to meet federal hazard mitigation planning requirements for all partners. The updated plan contains two volumes. Volume 1 contains components that apply to all partners and the broader Operational Area and the unincorporated areas of the County. Volume 2 contains all components that are planning partner specific. Each planning partner has a dedicated annex in Volume 2. A plan maintenance strategy which included annual progress reporting, a strategy for continued public involvement, a commitment to plan integration with other relevant plans and programs, and a recommitment from the planning partnership to actively maintain the plan over the five-year performance period. The Planning Team and the public were each provided opportunities to review the draft plan and inputs were incorporated into the final draft.

Phase 9: Develop and Adopt Final Multijurisdictional Hazard Mitigation Plan The final draft will be submitted to Cal OES and FEMA for approval. Once pre-adoption approval has been granted by the California Office of Emergency Services and FEMA Region 9, the final adoption phase will begin. Each planning partner will individually adopt the updated plan. Plan implementation will occur over the next five years as the planning partners begins to implement the countywide and jurisdiction-specific actions identified in this plan.

Each planning partner main point of contact is responsible for the maintenance of their annex and partner-specific information in this MJHMP. This includes documenting successes and lessons learned, researching new or updated data, laws, policies, regulations, or initiatives that can contribute to future iterations of the MJHMP, reviewing potential funding availability, and monitoring and tracking the progress of action items identified in their annex and submitting a status summary to the County’s project manager annually.

Mitigation Goals and Objectives
Hazard mitigation plans must identify goals for reducing long-term vulnerabilities to identified hazards (44 CFR Section 201.6(c)(3)(i)). A guiding principle, a set of goals and measurable objectives for this plan were reviewed and approved by the larger Planning Team based on data from the preliminary risk assessment and updates to mitigation priorities since the previous MJHMP. The guiding principle, goals, objectives, and actions in this plan all support each other. Goals were selected to support the guiding principle. Objectives were selected that met multiple goals. Actions were prioritized based on the action meeting multiple objectives.

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Guiding Principle
A guiding principle focuses the range of objectives and actions to be considered. This is not a goal because it does not describe a hazard mitigation outcome, and it is broader than a hazard-specific objective. The guiding principle for this MJHMP is as follows:

To equitably reduce risk and increase resilience by establishing and promoting a comprehensive mitigation program and efforts to protect the Whole Community and environment from identified natural and humaninduced hazards.

Goals
The following are the mitigation goals for this plan:

1. Actively develop community awareness, understanding, and interest in hazard mitigation and empower the Operational Area to engage in the shaping of associated mitigation policies and programs.

2. Minimize potential for loss of life, injury, social impacts, and dislocation due to hazards.

3. Minimize potential for damage to property, economic impacts, and unusual public expense due to hazards.

4. Minimize likelihood and impact of hazards causing environmental damage or damaging open space/nature preserves in the County and preserving ecological connectivity in the region and by working with residents to help build community capacity to respond and adapt to hazards and emergencies.

5. Effectively deliver essential information to the whole community that promotes personal preparedness and includes advice to reduce personal vulnerability to hazards.

6. Encourage programs and projects that promote community resiliency by maintaining the functionality of critical Operational Area resources, facilities, and infrastructure.

7. Pursue feasible, cost-effective, grant eligible, and environmentally sound hazard mitigation measures.

8. Increase adaptive capacity to reduce risk from hazard impacts that stem from a changing climate.

9. Remove barriers for local governments to access mitigation funding (broad vs. specific) and reduce the administrative pain points to recipient agencies during the project deployment and auditing phases.

The effectiveness of a mitigation strategy is assessed by determining how well these goals are achieved.

Objectives
Each selected objective meets multiple goals, serving as a stand-alone measurement of the effectiveness of a mitigation action, rather than as a subset of a goal. The objectives also are used to help establish priorities and have been reviewed and approved by the Mitigation Strategy Working Group, and the larger Planning Team. The objectives are as follows:

1. Establish and maintain partnerships in the identification and implementation of mitigation measures in the Operational Area.

2. Implement hazard mitigation programs and projects that protect life, property, and the environment.

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3. Develop and provide updated information about threats, hazards, vulnerabilities, and mitigation strategies to state, regional, and local agencies, as well as private sector groups, communitybased organizations, and non-profits.

4. Improve understanding of the locations, potential impacts, and linkages among threats, hazards, vulnerability, and measures needed to protect life, property, and the environment.

5. Encourage the incorporation of mitigation best management measures into plans, codes, and other regulatory standards for public, private, and non-governmental entities within the Operational Area.

6. Inform the public on the risk exposure to natural hazards and ways to increase the public’s capability to prevent, prepare, respond, recover, and mitigate impacts of these events.

7. Advance community and natural environment sustainability and resilience to future impacts through preparation and implementation of state, regional, and local projects.

8. Reduce repetitive property losses from all hazards.

9. Where feasible and cost-effective, encourage property protection measures for vulnerable structures located in hazard areas.

10. Improve the process on how public agencies select systems that provide warning and emergency communications for a broad array of agencies. This includes improving the selection process and ensuring warning and emergency communications processes are effective and accessible.

11. Partner with educational institutions that provide research, case studies and the like to help bolster agency communication that demonstrates the value of hazard mitigation.

Implementation
Full implementation of the recommendations of this plan will require time and resources. The measure of the plan’s success will be its ability to adapt to changing conditions. The County of Santa Clara and its planning partners will assume responsibility for adopting the recommendations of this plan and committing resources toward implementation. The framework established by this plan commits all planning partners to pursue actions when the benefits of a project exceed its costs. The planning partnership developed this plan with extensive public input, and public support of the actions identified in this plan will help ensure the plan’s success.

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Table of Contents
1 Introduction to Hazard Mitigation Planning....................................................................................... 1

1.1 Why Prepare This Plan? ............................................................................................................. 1

1.1.1 The Big Picture.......................................................................................................................... 1

1.1.2 Purposes for Planning............................................................................................................... 2

1.2 Who Will Benefit from This Plan?.............................................................................................. 3

1.3 Contents of This Plan ................................................................................................................. 3

1.3.1 Emergency Management Accreditation Program (EMAP)........................................................ 3 2 Plan Update: What Has Changed........................................................................................................ 4

2.1 The Previous Plan ....................................................................................................................... 4

2.2 Why Update? ............................................................................................................................... 4

2.2.1 Federal Eligibility ....................................................................................................................... 4

2.2.2 Plan Integration ......................................................................................................................... 5

2.2.3 Changes in Development.......................................................................................................... 5

2.3 Why Update? — What is Different?........................................................................................... 6 3 Planning for Climate Change and Equitable Outcomes................................................................. 10 4 Plan Update Approach ....................................................................................................................... 12

4.1 Grant Funding............................................................................................................................ 12

4.2 Formation of the Core Planning Team.................................................................................... 12

4.3 Defining Stakeholders .............................................................................................................. 13

4.4 Establishment of the Planning Partnership ........................................................................... 17

4.5 Defining the Planning Area ...................................................................................................... 21

4.6 Review of Existing Programs................................................................................................... 21

4.7 Public Involvement ................................................................................................................... 22

4.7.1 Strategy ................................................................................................................................... 22

4.7.2 Public Involvement Results ..................................................................................................... 27

4.8 Plan Development Chronology and Milestones..................................................................... 31 5 Santa Clara County Operational Area Profile .................................................................................. 33

5.1 Geographic Overview ............................................................................................................... 33

5.2 Historical Overview................................................................................................................... 33

5.3 Major Past Hazard Events ........................................................................................................ 35

5.4 Physical Setting ........................................................................................................................ 36

5.4.1 Geology and Topography........................................................................................................ 36

5.4.2 Soils......................................................................................................................................... 36

5.4.3 Climate .................................................................................................................................... 37

5.5 Development Profile ................................................................................................................. 38

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5.5.1 Land Use ................................................................................................................................. 38

5.5.2 Critical Facilities, Infrastructure, and Assets ........................................................................... 38

5.5.3 Future Trends in Development................................................................................................ 41

5.6 Demographics ........................................................................................................................... 42

5.6.1 Population ............................................................................................................................... 42

5.6.2 Age Distribution....................................................................................................................... 43

5.6.3 Race, Ethnicity, and Language ............................................................................................... 45

5.6.4 Education ................................................................................................................................ 45

5.6.5 Individuals with Disabilities or with Access or Functional Needs ............................................ 46

5.6.6. Social Vulnerability ..................................................................................................................... 46

5.7 Economy .................................................................................................................................... 49

5.7.1 Income..................................................................................................................................... 49

5.8 Industry, Businesses, and Institutions ................................................................................... 50

5.8.1 Employment Trends and Occupations .................................................................................... 50

5.9 Laws and Ordinances ............................................................................................................... 52

5.9.1 Federal .................................................................................................................................... 52

5.9.2 State ........................................................................................................................................ 60

5.9.3 Local........................................................................................................................................ 67 6 Identified Hazards of Concern and Risk Assessment .................................................................... 70

6.1 Identified Hazards of Concern ................................................................................................. 70

6.2 Hazard Risk Index ..................................................................................................................... 71

6.2.1 Average Overall Hazard Risk Index Results........................................................................... 74

6.3 Risk Assessment Tools............................................................................................................ 74

6.3.1 Mapping................................................................................................................................... 74

6.3.2 Hazus ...................................................................................................................................... 75

6.4 Risk Assessment Approach..................................................................................................... 75

6.4.1 Earthquake and Flood............................................................................................................. 76

6.4.2 Drought.................................................................................................................................... 77

6.4.3 All Other Assessed Hazards ................................................................................................... 77

6.5 EMAP Consequence Analysis ................................................................................................. 77

6.6 Sources of Data Used in Hazus Modeling .............................................................................. 78

6.6.1 Building and Cost Data ........................................................................................................... 78

6.6.2 Hazus Data Inputs................................................................................................................... 78

6.6.3 Other Local Hazard Data ........................................................................................................ 78

6.6.4 Data Source Summary............................................................................................................ 79

6.7 Limitations ................................................................................................................................. 80 7 Earthquake .......................................................................................................................................... 82

7.1 General Background................................................................................................................. 82

7.1.1 Damage from Earthquakes ..................................................................................................... 83

7.1.2 Earthquake Classifications...................................................................................................... 83

7.1.3 Ground Motion......................................................................................................................... 85

7.1.4 Effect of Soil Types ................................................................................................................. 87

7.2 Hazard Profile ............................................................................................................................ 88

7.2.1 Past Events ............................................................................................................................. 88

7.2.2 Location................................................................................................................................... 90

7.2.3 ShakeMaps ............................................................................................................................. 94

7.2.4 Frequency ............................................................................................................................. 100

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7.2.5 Severity ................................................................................................................................. 101

7.2.6 Warning Time........................................................................................................................ 102

7.3 Cascading Impacts ................................................................................................................. 103

7.4 Exposure.................................................................................................................................. 103

7.4.1 Population ............................................................................................................................. 103

7.4.2 Property................................................................................................................................. 104

7.4.3 Loss Potential........................................................................................................................ 104

7.4.4 Critical Facilities and Infrastructure....................................................................................... 108

7.4.5 Environment .......................................................................................................................... 109

7.5 Vulnerability............................................................................................................................. 109

7.5.1 Population ............................................................................................................................. 110

7.5.2 Property................................................................................................................................. 111

7.5.3 Critical Facilities and Infrastructure....................................................................................... 112

7.5.4 Environment .......................................................................................................................... 116

7.5.5 Economic Impact................................................................................................................... 116

7.6 Future Trends in Development .............................................................................................. 117

7.7 Scenario ................................................................................................................................... 118

7.8 Issues ....................................................................................................................................... 119 8 Wildfire............................................................................................................................................... 122

8.1 General Background............................................................................................................... 122

8.2 Hazard Profile .......................................................................................................................... 123

8.2.1 Past Events ........................................................................................................................... 123

8.2.2 Location................................................................................................................................. 126

8.2.3 Frequency ............................................................................................................................. 131

8.2.4 Severity and Impacts............................................................................................................. 133

8.2.5 Warning Time........................................................................................................................ 134

8.3 Cascading Impacts ................................................................................................................. 134

8.3.1 Smoke and Air Quality .......................................................................................................... 136

8.4 Exposure.................................................................................................................................. 137

8.4.1 Population ............................................................................................................................. 137

8.4.2 Property................................................................................................................................. 139

8.4.3 Critical Facilities and Infrastructure....................................................................................... 140

8.4.4 Environment .......................................................................................................................... 142

8.5 Vulnerability............................................................................................................................. 143

8.5.1 Population ............................................................................................................................. 143

8.5.2 Property................................................................................................................................. 144

8.5.3 Critical Facilities and Infrastructure....................................................................................... 146

8.5.4 Wildlife and Livestock............................................................................................................ 146

8.6 Future Trends in Development .............................................................................................. 146

8.7 Scenario ................................................................................................................................... 147

8.8 Issues ....................................................................................................................................... 148 9 Inclement Weather............................................................................................................................ 150

9.1 General Background............................................................................................................... 150

9.1.1 Heavy Precipitation/Atmospheric River................................................................................. 150

9.1.2 Extreme Temperatures ......................................................................................................... 154

9.1.3 High Winds ............................................................................................................................ 156

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9.1.4 Space Weather...................................................................................................................... 159

9.2 Hazard Profile .......................................................................................................................... 163

9.2.1 Past Events ........................................................................................................................... 163

9.2.2 Location................................................................................................................................. 169

9.2.3 Frequency ............................................................................................................................. 169

9.2.4 Severity ................................................................................................................................. 169

9.2.5 Warning Time........................................................................................................................ 170

9.3 Cascading Impacts ................................................................................................................. 170

9.4 Exposure.................................................................................................................................. 170

9.4.1 Population ............................................................................................................................. 170

9.4.2 Property................................................................................................................................. 171

9.4.3 Critical Facilities and Infrastructure....................................................................................... 171

9.5 Vulnerability............................................................................................................................. 171

9.5.1 Population ............................................................................................................................. 172

9.5.2 Property, Critical Facilities, Infrastructure ............................................................................. 172

9.5.3 Environment .......................................................................................................................... 173

9.5.4 Economy ............................................................................................................................... 173

9.6 Future Trends in Development, Scenario, Issues................................................................ 174

9.7 Issues ....................................................................................................................................... 174

9.8 Consequence Analysis........................................................................................................... 174 10 Drought ........................................................................................................................................ 176

10.1 General Background........................................................................................................... 176

10.1.1 Monitoring and Categorizing Drought................................................................................ 176

10.1.2 Normal Precipitation in California...................................................................................... 178

10.1.3 Water Supply Strategy ...................................................................................................... 179

10.1.4 Water Supply Infrastructure .............................................................................................. 181

10.2 Hazard Profile ...................................................................................................................... 183

10.2.1 Past Events ....................................................................................................................... 183

10.2.2 Location............................................................................................................................. 187

10.2.3 Frequency ......................................................................................................................... 187

10.2.4 Warning Time.................................................................................................................... 188

10.2.5 Extent ................................................................................................................................ 188

10.2.6 Severity and Impacts......................................................................................................... 189

10.2.7 Responses to Recent Drought.......................................................................................... 191

10.3 Cascading Hazards ............................................................................................................. 192

10.3.1 Drought and Wildfire ......................................................................................................... 192

10.3.2 Drought and Extreme Heat ............................................................................................... 192

10.3.3 Drought and Flooding........................................................................................................ 192

10.3.4 Drought and Landslides .................................................................................................... 193

10.4 Vulnerability......................................................................................................................... 193

10.4.1 Population ......................................................................................................................... 194

10.4.2 Property............................................................................................................................. 195

10.4.3 Critical Facilities ................................................................................................................ 195

10.4.4 Environmental Impact ....................................................................................................... 195

10.4.5 Economic Impact ............................................................................................................... 198

10.5 Future Trends in Development .......................................................................................... 198

10.6 Scenario ............................................................................................................................... 199

10.7 Issues ................................................................................................................................... 199

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11 Climate Change ........................................................................................................................... 201

11.1 General Background........................................................................................................... 201

11.1.1 Climate Change Indicators................................................................................................ 203

11.1.2 Projected Future Impacts .................................................................................................. 204

11.1.3 How Climate Change Impacts Hazard Mitigation ............................................................. 207

11.2 Responses to Climate Change .......................................................................................... 210

11.3 Vulnerability Assessment – Hazards of Concern ............................................................ 211

11.3.1 Earthquake ........................................................................................................................ 211

11.3.2 Wildfire .............................................................................................................................. 212

11.3.3 Inclement Weather ............................................................................................................ 213

11.3.4 Drought.............................................................................................................................. 214

11.3.5 Dam and Levee Failure..................................................................................................... 216

11.3.6 Flood ................................................................................................................................. 217

11.3.7 Landslide ........................................................................................................................... 219

11.3.8 Tsunami............................................................................................................................. 219

11.3.9 Extreme Temperatures ..................................................................................................... 220

11.3.10 Sea Level Rise .................................................................................................................. 222

11.4 Issues ................................................................................................................................... 227 12 Dam and Levee Failure ............................................................................................................... 229

12.1 General Background........................................................................................................... 229

12.2 Causes of Dam and Levee Failure..................................................................................... 229

12.2.1 Causes of Dam Failure ..................................................................................................... 229

12.2.2 Causes of Levee Failure ................................................................................................... 230

12.3 Hazard Profiles .................................................................................................................... 230

12.3.1 Past Dam Failure Events .................................................................................................. 230

12.3.2 Dam Location and Extent.................................................................................................. 234

12.3.3 Levee Location.................................................................................................................. 236

12.3.4 Frequency of Dam and Levee Failure............................................................................... 245

12.3.5 Severity ............................................................................................................................. 245

12.3.6 Warning Time for Dam Failure .......................................................................................... 245

12.3.7 Warning Time for Levee Failure........................................................................................ 246

12.4 Exposure .............................................................................................................................. 247

12.4.1 Population ......................................................................................................................... 247

12.4.2 Property............................................................................................................................. 247

12.4.3 Environment ...................................................................................................................... 247

12.5 Vulnerability......................................................................................................................... 247

12.5.1 Population ......................................................................................................................... 248

12.5.2 Property............................................................................................................................. 249

12.5.3 Critical Facilities ................................................................................................................ 249

12.5.4 Environment ...................................................................................................................... 249

12.6 Cascading Hazards ............................................................................................................. 251

12.7 Regulatory Oversight for Dams ......................................................................................... 251

12.7.1 National Dam Safety Act ................................................................................................... 251

12.7.2 U.S. Army Corps of Engineers Dam Safety Program ....................................................... 251

12.7.3 Federal Energy Regulatory Commission Dam Safety Program ....................................... 251

12.7.4 State of California.............................................................................................................. 252

12.7.5 Santa Clara Valley Water District...................................................................................... 253

12.7.6 Regulatory Oversight for Levees ...................................................................................... 254

12.8 Future Trends in Development .......................................................................................... 254

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12.9 Scenario ............................................................................................................................... 254

12.10 Issues ................................................................................................................................... 254

12.11 Consequence Analysis....................................................................................................... 255 13 Flood............................................................................................................................................. 257

13.1 General Background........................................................................................................... 257

13.1.1 Measuring Floods and Floodplains ................................................................................... 258

13.1.2 Floodplain Ecosystems ..................................................................................................... 258

13.1.3 Effects of Human Activities ............................................................................................... 259

13.1.4 Federal Flood Programs ................................................................................................... 259

13.2 Hazard Profile ...................................................................................................................... 265

13.2.1 Types of Flood-Related Hazards ...................................................................................... 266

13.2.2 Principal Flooding Sources ............................................................................................... 268

13.2.3 Past Events ....................................................................................................................... 269

13.2.4 Location............................................................................................................................. 273

13.2.5 Frequency ......................................................................................................................... 274

13.2.6 Severity ............................................................................................................................. 275

13.2.7 Warning Time.................................................................................................................... 288

13.3 Cascading Impacts ............................................................................................................. 288

13.4 Exposure .............................................................................................................................. 289

13.4.1 Population ......................................................................................................................... 289

13.4.2 Property............................................................................................................................. 290

13.4.3 Critical Facilities and Infrastructure................................................................................... 292

13.4.4 Environment ...................................................................................................................... 296

13.5 Vulnerability......................................................................................................................... 297

13.5.1 Population ......................................................................................................................... 298

13.5.2 Property............................................................................................................................. 300

13.5.3 Critical Facilities and Infrastructure................................................................................... 307

13.5.4 Environment ...................................................................................................................... 309

13.5.5 Economic Impact............................................................................................................... 309

13.6 Future Trends in Development .......................................................................................... 310

13.7 Scenario ............................................................................................................................... 310

13.8 Issues ................................................................................................................................... 311 14 Landslide/Mass Movement......................................................................................................... 313

14.1 General Background........................................................................................................... 313

14.1.1 Landslide Types ................................................................................................................ 313

14.1.2 Landslide Modeling ........................................................................................................... 315

14.1.3 Landslide Causes.............................................................................................................. 316

14.1.4 Landslide Management..................................................................................................... 317

14.1.5 Land Subsidence Effects .................................................................................................. 317

14.2 Hazard Profile ...................................................................................................................... 318

14.2.1 Past Events ....................................................................................................................... 318

14.2.2 Location............................................................................................................................. 327

14.2.3 Frequency ......................................................................................................................... 330

14.2.4 Severity ............................................................................................................................. 330

14.2.5 Warning Time.................................................................................................................... 330

14.3 Cascading Impacts ............................................................................................................. 331

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14.4 Exposure .............................................................................................................................. 331

14.4.1 Population ......................................................................................................................... 331

14.4.2 Property............................................................................................................................. 332

14.4.3 Critical Facilities and Infrastructure................................................................................... 333

14.4.4 Environment ...................................................................................................................... 336

14.5 Vulnerability......................................................................................................................... 336

14.5.1 Population ......................................................................................................................... 336

14.5.2 Property............................................................................................................................. 337

14.5.3 Critical Facilities and Infrastructure................................................................................... 337

14.5.4 Environment ...................................................................................................................... 338

14.6 Future Trends in Development .......................................................................................... 338

14.7 Scenario ............................................................................................................................... 338

14.8 Issues ................................................................................................................................... 338 15 Tsunami........................................................................................................................................ 341

15.1 General Background........................................................................................................... 341

15.1.1 Tsunami............................................................................................................................. 341

15.1.2 Seiche ............................................................................................................................... 343

15.2 Hazard Profile ...................................................................................................................... 343

15.2.1 Past Events ....................................................................................................................... 343

15.2.2 Location............................................................................................................................. 343

15.2.3 Frequency ......................................................................................................................... 344

15.2.4 Severity ............................................................................................................................. 345

15.2.5 Warning Time.................................................................................................................... 345

15.2.6 Extent ................................................................................................................................ 346

15.3 Cascading Impact................................................................................................................ 348

15.4 Exposure and Vulnerability................................................................................................ 348

15.4.1 Population ......................................................................................................................... 348

15.4.2 Property............................................................................................................................. 349

15.4.3 Critical Facilities and Infrastructure.................................................................................... 349

15.4.4 Environment ...................................................................................................................... 349

15.5 Future Trends in Development .......................................................................................... 349

15.6 Scenario ............................................................................................................................... 350

15.7 Issues ................................................................................................................................... 350 16 Other Hazards of Interest ........................................................................................................... 353

16.1 General Background........................................................................................................... 353

16.1.1 EMAP Consequence Analysis .......................................................................................... 354

16.2 Intentional Hazards ............................................................................................................. 355

16.2.1 Terrorism and Weapons of Mass Destruction................................................................... 355

16.2.2 Active Threat ..................................................................................................................... 361

16.2.3 Hazard Profile.................................................................................................................... 363

16.2.4 Cyber Threats.................................................................................................................... 366

16.2.5 Hazard Profile.................................................................................................................... 369

16.3 Technological Incidents ..................................................................................................... 370

16.3.2 Hazard Profile.................................................................................................................... 378

16.3.3 Utility Failure, Power Outages, and Public Safety Power Shutoff..................................... 379

16.3.4 Hazard Profile.................................................................................................................... 382

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16.4 Epidemic and Pandemic..................................................................................................... 384

16.4.2 Hazard Profile.................................................................................................................... 391

16.5 Fog........................................................................................................................................ 392

16.5.1 Hazard Profile.................................................................................................................... 393

16.6 Identified Needs................................................................................................................... 394

16.7 Related Plans....................................................................................................................... 396 17 Mitigation Strategy...................................................................................................................... 397

17.1 Goals and Objectives.......................................................................................................... 397

17.1.1 Guiding Principle ............................................................................................................... 397

17.1.2 Goals ................................................................................................................................. 397

17.1.3 Objectives.......................................................................................................................... 398

17.2 Mitigation Alternatives........................................................................................................ 398

17.3 Santa Clara County 2023 Mitigation Action Plan ............................................................. 411

17.4 Financial Capabilities ......................................................................................................... 430

17.4.1 Federal .............................................................................................................................. 430

17.4.2 State .................................................................................................................................. 437

17.4.3 Local.................................................................................................................................. 440

17.5 Action Plan Prioritization ................................................................................................... 440

17.5.1 Benefit-Cost Review.......................................................................................................... 441

17.6 Plan Adoption...................................................................................................................... 442

17.7 Plan Maintenance Strategy ................................................................................................ 442

17.8 Plan Implementation ........................................................................................................... 443

17.9 Plan Maintenance Element................................................................................................. 443

17.9.1 Plan Update....................................................................................................................... 444

17.9.2 Grant Monitoring and Coordination................................................................................... 445

17.9.3 Continuing Public Involvement.......................................................................................... 445

17.9.4 Incorporation into Other Planning Mechanisms ................................................................ 446 List of Tables
Table 1: Average Overall Hazard Risk Index Results..................................................................................xii Table 2: Summary of Changes in the 2023 MJHMP ....................................................................................7 Table 3: External Stakeholders Invited to Be Involved in Planning Process ..............................................13 Table 4: Planning Partner Main Points of Contact......................................................................................17 Table 5: One-on-One Meetings with Planning Partners .............................................................................18 Table 6: Summary of Public Outreach ........................................................................................................29 Table 7: Plan Development Chronology and Milestones............................................................................31 Table 8: Presidential Disaster Declarations8F ..............................................................................................35 Table 9: Normal Precipitation and Temperatures in the Operational Area, 1981–202210F...........................37 Table 10: Unincorporated County Land Use...............................................................................................38 Table 11: Critical Facilities and Infrastructure in the Operational Area ......................................................39 Table 12: Recent Population Data13F ............................................................................................................42 Table 13: Hourly Living Wage Calculation for Santa Clara County, California (2022)23F .............................49

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Table 14: Probability of Hazards.................................................................................................................72 Table 15: Hazard Risk Ranking by Jurisdiction ..........................................................................................73 Table 16: Average Overall Hazard Risk Index Results...............................................................................74 Table 17: Hazus Model Data Documentation .............................................................................................79 Table 18: Mercalli Scale and Peak Ground Acceleration Comparison45F .....................................................87 Table 19: National Earthquake Hazard Reduction Program Soil Classification System46F ..........................87 Table 20: Recent Earthquakes Magnitude 5.0 or Larger Within a 100-Mile Radius of the Operational Area ....................................................................................................................................................................89 Table 21: Earthquake Probabilities for the San Francisco Bay Area Region, 2014–204368F .....................101 Table 22: Earthquake Exposure by Jurisdiction........................................................................................104 Table 23: Loss Estimates for 100-Year Probabilistic Earthquake.............................................................105 Table 24: Loss Estimates for 500-Year Probabilistic Earthquake.............................................................105 Table 25: Loss Estimates for San Andreas Fault Scenario Earthquake...................................................106 Table 26: Loss Estimates for Hayward Fault Scenario Earthquake .........................................................106 Table 27: Loss Estimates for Calaveras Fault Scenario Earthquake .......................................................107 Table 28: Estimated Earthquake-Caused Debris .....................................................................................108 Table 29: Number of Critical Facilities Exposed to Earthquakes..............................................................109 Table 30: Estimated Earthquake Impact on Persons ...............................................................................110 Table 31: Age of Structures in Operational Area ......................................................................................111 Table 32: Estimated Damage to Critical Facilities from 100-Year Earthquake.........................................112 Table 33: Essential Facility Functionality in 100-Year Probabilistic Earthquake ......................................113 Table 34: Estimated Damage to Critical Facilities from 500-Year Earthquake.........................................113 Table 35: Estimated Damage to Critical Facilities from Hayward Fault....................................................113 Table 36: Estimated Damage to Critical Facilities from San Andreas Fault .............................................114 Table 37: Estimated Damage to Critical Facilities from Calaveras...........................................................114 Table 38: Damage to Potable Water Systems by Hazus Scenario ..........................................................116 Table 39: Damage to Waste Water Systems by Hazus Scenario ............................................................116 Table 40: EMAP Consequence Analysis: Earthquake..............................................................................120 Table 41: Past Wildfire Events..................................................................................................................123 Table 42: Record of Fire Affecting Operational Area................................................................................132 Table 43: Population Within Wildfire Hazard Areas ..................................................................................138 Table 44: Exposure and Value of Structures in Moderate to High Wildfire Hazard Areas .......................139 Table 45: Land Within the Wildfire Hazard Classification Areas...............................................................140 Table 46: Critical Facilities within Moderate to High Wildfire Hazard Areas .............................................141 Table 47: Critical Facilities Within 100 Meters of Moderate to High Wildfire Hazard Areas .....................141 Table 48: Loss Estimates for Wildfire within Moderate to High Wildfire Hazard Class.............................145 Table 49: EMAP Consequence Analysis: Wildfire ....................................................................................148 Table 50: NOAA Geomagnetic Storms Space Weather Scale and Potential Effects123F.............................160 Table 51: NOAA Solar Radiation Storms Space Weather Scale and Potential Effects124F..........................161 Table 52: NOAA Radio Blackouts Space Weather Scale and Potential Effects125F.....................................162 Table 53: 2001–2022 Heavy Rain and Hail Events ..................................................................................163 Table 54: 2001–2022 Extreme Temperature Events................................................................................166 Table 55:2002-2022 High Wind Events ....................................................................................................167 Table 56: 1951–2022 Tornado Events......................................................................................................168 Table 57: Population by Jurisdiction .........................................................................................................171 Table 58: EMAP Consequence Analysis Inclement Weather...................................................................174 Table 59: U.S. Department of Agriculture Disaster Declarations Including Santa Clara County, 2017– 2022 ..........................................................................................................................................................187 Table 60: Recent Federal and State Drought Responses ........................................................................191 Table 61: EMAP Consequence Analysis: Drought ...................................................................................199 Table 62: Average Maximum Temperature – Santa Clara County187F.........................................................205 Table 63: Number of Extreme Heat Days Per Year (Heat Is above 92.7 oF) Santa Clara County18F........206 Table 64: Average Annual Precipitation – Santa Clara County189F ..............................................................206 Table 65: Potential Direct and Related Climate Change Impacts in the Operational Area ......................208 Table 66: Climate Change Impacts on Natural and Other Hazards .........................................................209 Table 67: Wildfire – Projected Santa Clara County Acres Burned ...........................................................212

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Table 68: Population and Buildings at Risk – Santa Clara County...........................................................213 Table 69: Silicon Valley 2.0 Santa Clara County Sea Level Rise Projections and Inundation Layers .....222 Table 70: Estimated Population Residing in Sea Level Rise Inundation Areas .......................................223 Table 71: Structure Type in Sea Level Rise Inundation Areas .................................................................224 Table 72: Structure and Contents Value in Sea Level Rise Inundation Areas .........................................225 Table 73: Structure and Contents Value in Sea Level Rise Inundation Areas, Unincorporated Santa Clara County .......................................................................................................................................................225 Table 74: Critical Facilities in Sea Level Rise Inundation Areas...............................................................226 Table 75: EMAP Consequence Analysis: Climate Change ......................................................................227 Table 76: Dams Classified as a High Hazard or an Extremely High Hazard Risk 217F ,
218F ..............................231
Table 77: Levees in Santa Clara County 24F ...............................................................................................238 Table 78: Potential Downstream Hazard from Dams25F..............................................................................245 Table 79: Estimated Exposure and Value of Structures in the Dam Failure Inundation Area..................247 Table 80: Population in Dam Inundation Area ..........................................................................................248 Table 81: Value of Exposed Structures in the Dam Inundation Area by Jurisdiction ...............................250 Table 82: EMAP Consequence Analysis: Dam Failure ............................................................................255 Table 83: NFIP Status in the Operational Area ........................................................................................261 Table 84: CRS Community Status in the Operational Area246F....................................................................264 Table 85: History of Flood Events257F
,
258F........................................................................................................270 Table 86: Crop Insurance Claims Paid from Excessive Moisture and Flood, 2003-2022259F ......................272 Table 87: Summary of Peak Discharges Within the Operational Area260F ...................................................275 Table 88: Population Within the 10-Percent, 1-Percent, and 0.2-Percent Annual Chance Flood Hazard Areas .........................................................................................................................................................289 Table 89: Value of Structures in the 10-Percent Annual Chance Flood Hazard Area..............................290 Table 90: Value of Structures in the 1-Percent Annual Chance Flood Hazard Area................................291 Table 91: Value of Structures in the 0.2-Percent Annual Chance Flood Hazard Area.............................292 Table 92: Critical Facilities in the 10-Percent Annual Chance Flood Hazard Area ..................................293 Table 93: Critical Facilities in the 1-Percent Annual Chance Flood Hazard Area ....................................293 Table 94: Critical Facilities in the 0.2-Percent Annual Chance Flood Hazard Area .................................294 Table 95: Habitats Expected to Be Impacted by Riverine Flooding265F........................................................296 Table 96: Estimated Flood Impact on Persons .........................................................................................298 Table 97: Loss Estimates for 10-Percent-Annual-Chance Flood..............................................................300 Table 98: Loss Estimates for 1-Percent-Annual-Chance Flood................................................................301 Table 99: Loss Estimates for 0.2-Percent-Annual-Chance Flood.............................................................302 Table 100: Estimated Flood-Caused Debris .............................................................................................303 Table 101: Flood Insurance Statistics268F.....................................................................................................304 Table 102: Date of Floodplain Management Regulation Adoption ...........................................................305 Table 103: Repetitive Loss Properties ......................................................................................................306 Table 104: Substantial Damage/Substantial Improvement Implementation.............................................307 Table 105: Estimated Damage to Critical Facilities and Infrastructure from the 10% Annual Chance Flood ..................................................................................................................................................................307 Table 106: Estimated Damage to Critical Facilities and Infrastructure from the 1% Annual Chance Flood ..................................................................................................................................................................308 Table 107: Estimated Damage to Critical Facilities and Infrastructure from the 0.2% Annual Chance Flood ..................................................................................................................................................................308 Table 108: EMAP Consequence Analysis: Flood .....................................................................................312 Table 109: Landslide Events in Santa Clara County27F
,
278F
,
279F
,
280F
,
281F..................................................................319 Table 110: Population Exposed to Landslide Hazard...............................................................................331 Table 111: Exposure and Value of Structures in Moderate to High Landslide Risk Areas ......................332 Table 112: Acreage in Moderate to High Landslide Hazard Areas ..........................................................333 Table 113: Critical Facilities and Infrastructure in Moderate to Very High Landslide Risk Areas.............335 Table 114: Loss Potential Based on All Building Stock in Aggregated Landslide Areas..........................337 Table 115: EMAP Consequence Analysis: Landslide/Mass Movement ...................................................339 Table 116: Tsunami Intensity Scale297F ........................................................................................................346 Table 117: EMAP Consequence Analysis: Tsunami ................................................................................351 Table 118: EMAP Consequence Analysis: Other Hazards of Interest .....................................................354

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Table 119: Event Profiles for Terrorism301F ..................................................................................................357 Table 120: Santa Clara County Hazardous Materials Spills 2019–202232F................................................372 Table 121: Corrosion Type........................................................................................................................375 Table 122: Leak Classifications ................................................................................................................377 Table 123: Electric Providers in Santa Clara County30F..............................................................................381 Table 124: Power Shutoffs Statewide31F .....................................................................................................382 Table 125: COVID-19 Cases Countywide and by City of Residence36F .....................................................386 Table 126: Disease Outbreaks Identified in Santa Clara County, 2018–202234F .......................................387 Table 127: Alternatives to Mitigate the Dam and Levee Failure Hazard ..................................................399 Table 128: Alternatives to Mitigate the Drought Hazard ...........................................................................400 Table 129: Alternatives to Mitigate the Earthquake Hazard .....................................................................401 Table 130: Alternatives to Mitigate the Flooding Hazard ..........................................................................403 Table 131: Alternatives to Mitigate the Landslide/Mass Movement Hazard.............................................406 Table 132: Alternatives to Mitigate the Inclement Weather Hazard..........................................................407 Table 133: Alternatives to Mitigate the Tsunami Hazard ..........................................................................408 Table 134: Alternatives to Mitigate the Wildfire Hazard............................................................................410 Table 135: County of Santa Clara 2023 Action Items...................................Error! Bookmark not defined.

Table 136: FEMA Mitigation Funding Sources .........................................................................................431 Table 137: Additional Federal Funding Sources.......................................................................................434 Table 138: State Mitigation Funding Sources ...........................................................................................437 Table 139: Plan Maintenance Matrix ........................................................................................................443 Table 140: Survey Results Level of Hazard Concern............................................................................... A-2 Table 141: Level of Concern for Climate Change Impacts ....................................................................... A-2 Table 142: Types of Stakeholders Represented....................................................................................... A-3 Table 143: Public Comments .................................................................................................................... A-3 Table 144: General Feedback Received ................................................................................................ A-16 List of Figures
Figure 1: Planning Partners Meeting ..........................................................................................................20 Figure 2: Planning Partners Mitigation Strategy Meeting ...........................................................................21 Figure 3: Picture of Public Survey Announcement .....................................................................................23 Figure 4: Public Survey Media Announcement...........................................................................................24 Figure 5: City of Campbell Social Media Outreach.....................................................................................25 Figure 6: Hazard Exposure and Social Vulnerability Map for Santa Clara Valley ......................................27 Figure 7: Public and Stakeholder Meeting with 99 Participants..................................................................28 Figure 8: Public and Stakeholder Meeting with 104 Participants................................................................29 Figure 9: Samples of Public Comment Period Advertisements ..................................................................30 Figure 10: Santa Clara County Operational Area (Planning Area).............................................................34 Figure 11: Critical Facilities in the Operational Area...................................................................................40 Figure 12: Critical Infrastructure in the Operational Area ...........................................................................41 Figure 13: Overall Age Distribution in the Operational Area17F.....................................................................44 Figure 14: Race Distribution in the Operational Area19F ...............................................................................45 Figure 15: Santa Clara County Social Vulnerability Index ..........................................................................47 Figure 16: Social Vulnerability Index Themes.............................................................................................48 Figure 17: Industry in Santa Clara County..................................................................................................50 Figure 18: Occupations in Santa Clara County...........................................................................................51 Figure 19: California and Santa Clara County Unemployment Rate27F ........................................................52 Figure 20: Modified Mercalli Intensity Scale42F..............................................................................................85 Figure 21: Peak Acceleration (%g) with 10% Probability of Exceedance in 50 Years4F .............................86 Figure 22: Historic Earthquakes in the Operational Area ...........................................................................90

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Figure 23: Significant Known Faults in the Bay Area56F................................................................................92 Figure 24: 500-Year Probabilistic Earthquake Scenario Peak Ground Acceleration..................................94 Figure 25: Hayward Magnitude 7.0 Fault Scenario Peak Ground Acceleration .........................................96 Figure 26: Calaveras Magnitude 7.0 Fault Scenario Peak Ground Acceleration .......................................97 Figure 27: San Andreas Magnitude 7.8 Fault Scenario Peak Ground Acceleration...................................98 Figure 28: Liquefaction Susceptibility .........................................................................................................99 Figure 29: Peak Ground Acceleration with 10-percent Probability of Exceedance in 50 Years...............102 Figure 30: Highway Bridge Percentage Damage Exceeds Moderate: Calaveras Scenario.....................115 Figure 31: Hayward Fault Earthquake Scenario80F .....................................................................................119 Figure 32: Air Tanker Dropping Fire Retardant on Lick Fire in Santa Clara County86F ..............................126 Figure 33: Fire Hazard Severity Zones (FSHZ) ........................................................................................128 Figure 34: Classified Wildfire Hazard........................................................................................................130 Figure 35: Wildfire Risk to Structures .......................................................................................................131 Figure 36: Burned Hillslopes above Pulse Canyon near San Antonio Valley, SCU Lightning Complex, Santa Clara County94F.................................................................................................................................133 Figure 37: Post Fire Soil Erosion Potential ...............................................................................................135 Figure 38: NOAA Atlas Intensity - Santa Clara, California........................................................................151 Figure 39: Thunderstorm Life Cycle13F........................................................................................................153 Figure 40: National Weather Service Wind Chill Chart.............................................................................154 Figure 41: Winter Storm Severity Index ....................................................................................................155 Figure 42: National Weather Service Heat Index Chart17F..........................................................................156 Figure 43: National Weather Service Heat Index Classifications and Corresponding Effects on the Body18F ..................................................................................................................................................................156 Figure 44: The Beaufort Wind Scale12F .......................................................................................................158 Figure 45: Palmer Drought Index from January 1, 2005, to May 20, 2023129F.............................................177 Figure 46: Palmer Hydrological Drought Index from January 1, 2005, to May 20, 2023130F........................177 Figure 47: Santa Clara Valley Water District System Water Supply14F.......................................................182 Figure 48: Hetch Hetchy Water System146F..................................................................................................183 Figure 49: U.S. Drought Monitor Time Series California 2000-2023 ........................................................188 Figure 50: U.S. Drought Monitory Map of California.................................................................................189 Figure 51: Reported Number of Drought Impacts by Category156F ..............................................................190 Figure 52: CMRA Drought Hazard: Days without Precipitation Indicator for Santa Clara County ...........194 Figure 53: Tier 1 Tree Mortality High Hazard Zones162F...............................................................................197 Figure 54: Tier 2 Tree Mortality High Hazard Zones163F...............................................................................197 Figure 55: Global Temperature 1880-202217F.............................................................................................202 Figure 56: Global Carbon Dioxide Concentrations Over Time174F................................................................203 Figure 57: Impacts of Climate Change on Human Health190F ......................................................................207 Figure 58: Location of Dams Impacting Santa Clara County21F..................................................................235 Figure 59: Dam Inundation Depth Grids ...................................................................................................236 Figure 60: Levees in Santa Clara County23F ...............................................................................................237 Figure 61: Risk Rating 2.0: Project Premium Changes for Santa Clara County24F.....................................263 Figure 62: CRS Communities by Class Nationwide as of October 2022245F................................................264 Figure 63: Watersheds in the Operational Area256F......................................................................................269 Figure 64: Mapped Flood Hazard Areas in the Operational Area.............................................................274 Figure 65: 100-Year Floodplain Area Land Cover26F ..................................................................................297 Figure 66: Common Types of Landslides .................................................................................................314 Figure 67: Typical Debris Avalanche Scar and Track27F.............................................................................315 Figure 68: A Santa Clara County Debris Flow Triggered by Winter Storms Following the Loma Fire, 201728F ..................................................................................................................................................................326 Figure 69: SCVWD Historic Groundwater Conditions284F.............................................................................327 Figure 70: Deep-Seated Landslide Susceptibility in Santa Clara County.................................................329 Figure 71: Potential Tsunami Travel Times in the Pacific Ocean, In Hours291F ...........................................342 Figure 72: Tsunami Hazard Area..............................................................................................................344 Figure 73: Weapon Types Used in Terrorist Events in California310F...........................................................364 Figure 74: Targets of Terrorist Attacks in California31F ...............................................................................365 Figure 75: Highly Populated Areas with Hazardous Material Incidents Within Santa Clara County32F .....371

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Figure 76: Gas and Hazardous Liquids Pipelines in Santa Clara County325F ..............................................374 Figure 77: Santa Clara COVID Cases 2020–202335F .................................................................................385 Figure 78: Weekly Percentage of Emergency Department Visits for Influenza-Like Illness in Santa Clara County, 2019, to February 22, 202334F .......................................................................................................388 Figure 79: Sample of Public Survey Advertisement ................................................................................. A-1 Figure 80: Sample Public Feedback on Hazard Impacts - Gilroy Meeting ............................................. A-14 Figure 81: Sample Public Feedback on Hazard Impacts - Campbell Meeting ....................................... A-15 Figure 82: Sample In-Person Feedback Option - Gilroy Meeting........................................................... A-16

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 1: Introduction to Hazard Mitigation Planning 1 1 Introduction to Hazard Mitigation Planning

1.1 Why Prepare This Plan?

1.1.1 The Big Picture
Hazard mitigation is a key component of community resilience. There is no one definition of resilience; however, the Urban Sustainability Directors Network defines resilience as the ability of people and their communities to anticipate, accommodate and positively adapt to or thrive amidst changing climate conditions and hazard events.0F
1 The Federal Emergency Management Agency (FEMA) defines hazard mitigation as any sustainable action that reduces or eliminates long-term risk to people and property from future disasters.1F
2 It involves long- and short-term actions implemented before, during, and after disasters.

Hazard mitigation activities include planning and regulations, structure and infrastructure projects, natural system protection, and education and awareness programs as well as other steps to reduce the impact of hazards.

For many years, federal disaster funding focused on relief and recovery after disasters occurred, with limited funding for hazard mitigation planning in advance. The Disaster Mitigation Act (DMA; Public Law 106-390), passed in 2000, shifted the federal emphasis toward planning for disasters before they occur.2F 3 The DMA requires state and local governments to develop hazard mitigation plans as a condition for federal disaster grant assistance. Regulations developed to fulfill the DMA’s requirements are included in Title 44 of the Code of Federal Regulations (44 CFR).

FEMA advocates for a “whole community” approach to hazard mitigation. This approach calls for everyone, from private property owners to commercial interests to nonprofits and local, state, and federal governments to be involved in preparing the nation for the next disaster event. By going through the local planning process outlined in the DMA, communities are able to articulate their needs for mitigation more easily. based on their understanding of their capabilities and risk. This can enhance their ability to develop projects and take mitigation actions, resulting in faster allocation of funding and more costeffective risk-reduction projects.

The DMA also promotes sustainability in hazard mitigation. To be sustainable, hazard mitigation needs to incorporate sound management of natural resources and consider the wider social and economic implications.
1 Urban Sustainability Directors Network. (n.d.). Resilience Hubs.

USDN%20Resilience%20Hubs%20Guidance%20Document
2 Federal Emergency Management Agency. (n.d.). Hazard Mitigation Assistance Grants. https://www.fema.gov/grants/mitigation#:~:text=FEMA%27s%20hazard%20mitigation%20assistance%20provides%2 0funding%20for%20eligible,cycle%20of%20disaster%20damage%2C%20reconstruction%20and%20repeated%20da mage.
3 Federal Emergency Management Agency. (2020, October 19). The Disaster Mitigation Act of 2000. https://www.fema.gov/blog/disaster-mitigation-act-2000-20-years-mitigation-planning

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 1: Introduction to Hazard Mitigation Planning 2 To further enhance the planning process and the guidelines set by DMA, the Santa Clara County Office of Emergency Management follows a specific emergency management planning process. This locally developed process incorporates various nationally recognized best practices and concepts, like the whole community planning approach, with standard program management principles that can be easily integrated into the County’s existing governmental structure. This process brings together stakeholders, builds lasting community relationships, and results in a stronger and more comprehensive mitigation plan.

This process is key to building community resilience and was followed in the 2023 MJHMP update.

1.1.2 Purposes for Planning
Hazard mitigation planning is the foundation for mitigation investments. Hazard mitigation plans are required to be updated, approved, and adopted every five years in order to maintain eligibility for multiple federal mitigation grant programs. Through the update process, mitigation actions are developed as a part of a community-based, risk-informed decision-making process.3F 4 Fourteen jurisdictions and three special districts within the Santa Clara County Operational Area (OA)— defined as the unincorporated county, incorporated jurisdictions, and special districts within the geographical boundaries of Santa Clara County—participated in the Multijurisdictional Hazard Mitigation Plan (MJHMP) prepared in 2023 by the Santa Clara County Office of Emergency Management with support from the consulting firm IEM. Participating jurisdictions and districts are referred to in this plan as planning partners. Elements and strategies in the MJHMP were selected because they meet a program requirement and because they meet the needs of the planning partners and their residents. One of the benefits of multijurisdictional planning is the ability to pool resources and support partnerships to reduce redundant activities within the OA that have similar risk exposure and vulnerabilities. FEMA encourages multijurisdictional planning under its guidance for the DMA. This MJHMP will help guide and coordinate mitigation activities throughout the OA. Additionally, it was developed to meet the following objectives:
 Meet or exceed requirements of the DMA.
 Comply with the requirements outlined in FEMA’s Local Mitigation Policy Planning Guide (April 2022), the requirements of which apply to all plans seeking agency approval on or after April 19, 2023.
 Enable all planning partners to continue using federal grant funding to reduce risk through mitigation.
 Meet the planning requirements of FEMA’s Community Rating System (CRS), allowing planning partners that participate in the CRS program to maintain or enhance their CRS classifications.  Utilize EMAP standards for strategic planning.
 Coordinate existing plans and programs so high priority projects to mitigate possible disaster impacts have an increased opportunity to be funded and implemented.

The planning partners discussed using this plan to meet Community Rating System (CRS) requirements as well. Ultimately, it was decided that Santa Clara Valley Water will lead the development of a separate Floodplain Management Plan specifically dedicated towards this goal, allowing planning partners that participate in the CRS program to maintain or enhance their CRS classifications. Relevant information from this MJHMP will be incorporated into the Floodplain Management Plan. 4 Federal Emergency Management Agency. (2022, April 19). Local Mitigation Planning Policy Guide. https://www.fema.gov/sites/default/files/documents/fema_local-mitigation-planning-policy-guide_042022.pdf

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1.2 Who Will Benefit from This Plan?
The whole community of the Santa Clara County OA—including individual and families, businesses, community and nonprofit organizations, schools and academia, and all levels of government—is the ultimate beneficiary of this MJHMP. Implementing the plan will reduce risk for those who live in, work in, and visit the OA. The plan provides a viable planning framework for natural hazards of concern for the area. Participation in development of the plan by key stakeholders helped ensure outcomes will be mutually beneficial. The resources and background information in the plan are applicable across the OA, and the plan’s goals and recommendations can lay the groundwork for the development and implementation of local mitigation activities and partnerships for years to come. Mitigation projects, particularly large projects with cascading impacts, will also benefit neighboring jurisdictions.

1.3 Contents of This Plan
This plan has been set up in two volumes so that elements that are planning partner-specific can easily be distinguished from those that apply to the overall Santa Clara County OA:
 Volume 1: Volume 1 includes all federally required elements of a disaster mitigation plan that apply to the OA and the unincorporated areas of the County. This includes the description of the planning process, public involvement strategy, goals and objectives, hazard risk assessment, mitigation actions, and a plan maintenance strategy.
 Volume 2: Volume 2 includes all federally required participant-specific elements, in annexes for each participating entity. It includes a description of the participation requirements established for participants in this plan.

Both volumes include elements required under federal guidelines. DMA compliance requirements are cited at the beginning of subsections as appropriate to illustrate compliance.

The following appendices provided at the end of Volume 1 include information or explanations to support the main content of the plan:
 Appendix A: Public outreach information used in preparation of this update.  Appendix B: Plan adoption resolutions from planning partners.

All planning partners will adopt the MJHMP once it has been reviewed by FEMA and reaches Approvable-Pending-Adoption (APA) status.

1.3.1 Emergency Management Accreditation Program (EMAP) This plan incorporates elements of the Emergency Management Standard set by the Emergency Management Accreditation Program (EMAP). A consequence analysis of the potential for detrimental impacts of hazards is included in this 2023 plan update for the EMAP. Each hazard identified in this plan is followed by the Consequence Analysis result. The methodology of this analysis and the results can be found in the Risk Assessment portion in Volume 1 of this plan.

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2 Plan Update: What Has Changed

2.1 The Previous Plan
Santa Clara County, 15 jurisdictions, and the Santa Clara County Fire Department were covered under the 2017 Santa Clara County Operational Area (OA)Hazard Mitigation Plan. The planning process used to develop the 2017 plan was as follows:
 Definition of the planning area and establishment of a working group of participating stakeholders which oversaw all phases of the plan update.
 Promotion of focused outreach to individuals identified for the working group as well as other individuals, agencies, and jurisdictions that had a vested interest in the recommendations in the hazard mitigation plan.
 Development of a strategy for public involvement in the plan update which included inviting members of the public to serve on the working group, conducting a public survey, utilizing multiple media avenues, and actively identifying and involving OA stakeholders.  Assessment of existing programs including plans, studies, reports and technical information and all planning and regulatory, administrative, and technical, public outreach and education, and financial capabilities of planning partners to implement hazard mitigation actions.  Reevaluation of the 2010 plan update to ensure planning partners had the opportunity to provide comment.

Santa Clara Valley Water District had a 2017 Local Hazard Mitigation Plan independent of the 2017 Santa Clara County Operational Area Hazard Mitigation Plan. The district joined the OA Mitigation Plan as part of the 2023 Multijurisdictional Hazard Mitigation Plan (MJHMP) update. The Midpeninsula Regional Open Space and Santa Clara County Fire Department also joined the 2023 plan update.

2.2 Why Update?

2.2.1 Federal Eligibility
Hazard mitigation plans are updated on a five-year cycle. A jurisdiction or special district covered by a plan that has expired is not able to pursue elements of federal funding under the Robert T. Stafford Act for which a current hazard mitigation plan is a prerequisite. Title 44 of the Code of Federal Regulations (44 CFR) stipulates that hazard mitigation plans must present a schedule for monitoring, evaluating, and updating the plan. This provides an opportunity to reevaluate recommendations, monitor the impacts of actions that have been completed, and determine if there is a need to change the focus of mitigation strategies. This update meets the requirements for hazard mitigation plans in order to maintain the eligibility for federal grant funding for Planning Participants.

Additionally, on April 19, 2022, FEMA updated the Local Mitigation Planning Policy Guide. This means that all plans updated and approved after April 19, 2023, must adhere to the new mitigation planning policy requirements. The 2023 update of the Santa Clara MJHMP has incorporated all changes and is in compliance with all elements of the updated Local Mitigation Planning Policy Guide. The Santa Clara County Multijurisdictional Hazard Mitigation Plan is proud to be one of the only MJHMPs in the state to incorporate the updated guidance. Some of these elements include:

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 Incorporating a broad range of representatives in the planning process, including organizations that support underserved communities.
 Incorporating the effects of climate change and future conditions in the risk assessment.  Emphasizing the importance of building codes, land use ordinances, and developmental regulations in local capabilities.
 Emphasizing the alignment of FEMA related mitigation programs, such as the NFIP.

2.2.2 Plan Integration
Since the last plan update, the Santa Clara County Office of Emergency Management has worked diligently to incorporate the 2023 MJHMP into other county wide planning initiatives.

Santa Clara County Safety Element (the Safety Element): The County is undergoing the 2023 Safety Plan update, which is part of the Santa Clara County General Plan. The purpose of the Santa Clara County Safety Element is to identify and include safety considerations during the decision-making and planning process by establishing goals and policies as they relate to future developments within the County. These goals and policies aim to reduce personal injury and loss of life, prevent property destruction, and reduce environmental damage throughout the community. The Safety Element focuses on addressing potential hazards such as earthquakes, flooding, wildfire, and more. The Safety Element, which will be completed in the Fall of 2023, incorporates risk and hazard data developed during the 2017 MJHMP update. It also strategically aligns with the mitigation goals and actions from the MJHMP.

Integration between the Safety Element and the MJHMP+
ensures the County is maximizing their future funding opportunities to reduce risk in the County and comply with Assembly Bill 2140 (2006), which affords the county additional benefits under the California Disaster Assistance Act.

Santa Clara County Community Wildfire Protection Plan (CWPP): In addition, the Santa Clara County Office of Emergency Management collaborated with the Santa Clara Fire Safe Council to integrate the MJHMP and the Santa Clara County Community Wildfire Protection Plan (CWPP). The CWPP identifies potential priority areas where mitigation measures are needed to protect from wildfire the irreplaceable life, property, and critical infrastructure within the County. The CWPP directly aligns with the MJHMP mitigation strategy and provides an even more in depth look at the County’s wildfire risk.

2.2.3 Changes in Development
Hazard mitigation plan updates must reflect changes in development within the OA since the previous plan (44 CFR Section 201.6(d)(3)). The plan must describe development changes in hazard-prone areas that increased or decreased vulnerability for each planning partner since the last plan was approved. If no changes in development impacted the partner’s overall vulnerability, plan updates may validate the information in the previously approved plan. The intent of this requirement is to ensure the plan’s mitigation strategy continues to accurately address the risk and vulnerability of existing and potential development and takes into consideration possible future conditions that could impact vulnerability.

According to data from the California Department of Finance, the OA decreased in population by .5 percent between 2015 and 2022.4F
5 The COVIID-19 pandemic, relocation of remote workers, and rising cost of housing likely contributed to some of this change. Other large urban centers around the nation experienced similar trends during the pandemic.
5 California Department of Finance. (n.d.). Demographic Reports. https://dof.ca.gov/reports/demographic-reports/

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Participating planning partners have adopted General Plans that govern land-use decisions and policymaking, as well as building codes and specialty ordinances based on state and federal mandates.5F 6 Information on planning partner-specific changes in development is included in the participant annexes in Volume 2.

2.3 Why Update? — What is Different?
This update seeks to capitalize on some of the successes of the prior plan update, including the good participation rates and format changes. The Santa Clara County OA’s 2010 Hazard Mitigation Plan Update was prepared under the ABAG process however, the County OEM determined that the new format established in the 2017 multijurisdictional hazard mitigation plan update would be best to use moving forward as it better suits the needs and capabilities of the planning partners.

The plan update process included a greater focus on public involvement that concentrated on targeted public engagement instead of simply opening technical workshops to the public. A renewed effort was made to establish a plan maintenance and implementation protocol that clearly defines ongoing commitment to the plan’s success. Some of the major differences between the current and previous plans are as follows:
• The plan has been totally restructured as an Operational Area plan, focusing only on the geographic area of Santa Clara County. The risk assessment is not a subset of a larger regional effort. Instead, it is isolated to the Santa Clara County OA and focuses on the hazards of concern for the OA.
• The risk assessment has been prepared to best support future grant applications by providing information on risk and vulnerability that will directly support the measurement of “costeffectiveness” required under FEMA mitigation grant programs. • Newly available data and tools provide for a more detailed and accurate risk assessment using means such as FEMA’s Hazards U.S. (Hazus) Multi-Hazard computer model or new data such as FEMA’s countywide Digital Flood Insurance Rate Maps. • The planning process creates the opportunity for all municipal planning partners to prepare to meet the requirements of California Senate Bill 379 during the next plan update. That bill will require integration of quantitative climate change risk assessment in the development of climate change related initiatives as part of the safety element of general plans. • The plan is more user-friendly because it is confined to one package. • The update created an opportunity for the County of Santa Clara, local cities and towns, and other planning partners to engage citizens directly in a coordinated approach to gauge their perception of risk and support of the concept of risk reduction through mitigation. 6 San José Spotlight. (2022, April 2). Silicon Valley Residents Left in Droves During Pandemic. https://sanjosespotlight.com/silicon-valley-san-jose-santa-clara-sunnyvale-residents-left-in-droves-exodus-duringcovid-19-pandemic/

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• While priorities have remained the same, the plan’s goals objectives and actions are more clearly defined. The plan identifies actions rather than strategies as was the case with the prior plans. Strategies provide direction, but actions are fundable under grant programs. This plan replaces strategies with a guiding principle, goals, and objectives. The actions identified meet multiple objectives that are measurable, so that each planning partner can measure the effectiveness of its mitigation actions, which was difficult prior to this plan update.

Below is a table comparing the 2017 MHJMP and 2023 MHJMP. Changes to the plan’s format and contents involved a multistep process that included best practices research and an assessment of jurisdiction and special district planning needs.

Table 2: Summary of Changes in the 2023 MJHMP
Changes Throughout the Plan
• Comprehensive review and update of hazard history, risk and vulnerability data and information • New hazards of climate change, sea-level rise, wildfire smoke, and air quality added • Expanded outreach to vulnerable and historically underserved populations • Lens of planning for climate change and equitable outcomes used to create a comprehensive and inclusive plan
• Integrated MJHMP planning process with the planning processes of the Community Wildfire Protection Plan and Safety Element of the General Plan update • It was determined that all CRS requirements will be met in a forthcoming floodplain management plan created by Santa Clara Valley Water District
• City of Monte Sereno was not an active participant in this plan update, but is referenced in the plan as applicable
• Santa Clara Valley Water District and Midpeninsula Regional Open Space District joined as Planning Partners
• Plan was updated to meet 2023 FEMA hazard mitigation plan guidance and requirements Volume I: Base Plan
Section Changes
Section 1: Introduction to Hazard
Mitigation Planning
• Updated explanation of importance and purpose of hazard mitigation planning
Section 2: Plan Update: What Has
Changed
• Summary list of plan changes and updates included
Section 3: Planning for Climate
Change and Equitable Outcomes
• Section added to highlight Santa Clara County’s goal of continuing to integrate equity into all aspects of emergency management Section 4: Plan Update Approach • Information added to highlight the concentrated effort to ensure plan integration between the County Community Wildfire
Protection Plan and County Safety Element of the County General Plan updates as well as other approved plans
• Explanation of the ways planning partners engaged residents, particularly those who are underserved and/or socially vulnerable,

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Volume I: Base Plan
Section Changes
and gauged their perception of risk and support for risk reduction through mitigation
• Explanation of the ways planning partners engaged community stakeholders, particularly those that assist underserved and/or socially vulnerable, and gauged their perception of risk and support for risk reduction through mitigation
• Updated plan development chronology and milestones
Section 5: Santa Clara County
Operational Area Profile
• All information updated using the most recent data available Sections 6-16: Identified Hazards
of Concern and Risk Assessment
• The risk assessment includes further considerations of emerging hazards, like the impact of climate change, wildfire smoke, and air quality, which have recently impacted the OA with increasing frequency since the 2017 plan
• Hazard risk ranking updated and is now hazard risk index criteria • Wildfire, drought, and climate change are now considered to have higher average overall hazard risk by Planning Partners when compared to their hazard risk ranking scores in the 2017 plan • Updated and expanded information on hazard history, location, extent, frequency, and severity; exposure, vulnerability, cascading hazards, and how climate change may impact the frequency, extent, and severity of each hazard
• The risk assessment has been formatted to provide information on risk and vulnerability that will allow a measurement of costeffectiveness • Severe weather terminology updated to inclement weather • Updated maps and graphics
• Hazus data and findings updated
• The plan was developed in accordance with the most recent EMAP standards
• Latest disaster declaration data added
• High Hazard Potential Dam Grant Program (HHPD) requirements were considered and referenced
Section 17: Mitigation Strategy • Mitigation goals and objectives and criteria for mitigation action item prioritization have been updated to include climate change, resiliency, and benefits to populations that are underserved and/or socially vulnerable.
• Expanded detail on plan monitoring, evaluating, and updating to include roles and responsibilities and description of specific methods and schedules

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Volume 2: Planning Partner Annexes
• Each Planning Partner has a minimum of one mitigation action per a hazard that can impact them • Actions and project identified in the Santa Clara County Community Wildfire Protection Plan included in annexes, as applicable
• Expanded information about Planning Partner participation and compliance in the National Flood Insurance Program
• All data and information updated, including Local Planning Team members, jurisdiction or special district profile, capability assessment, opportunities to integrate the mitigation plan into other local planning initiatives, hazard event history, jurisdiction- or special district-specific vulnerabilities, future development trends, hazard risk index, future needs to better understand risk and vulnerability, status of previous action items, and maps.
• Mitigation successes highlighted, as applicable
• Risk and vulnerability assessment expanded to include climate change, wildfire smoke, and air quality • Local floodplain managers identified by name in each annex, as applicable • Development trends since the 2017 plan identified
• Sea-level rise map added to the City of Palo Alto’s annex Appendices
• Appendix B updated from progress report template to adoption resolutions from all participating jurisdictions.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 3: Planning for Climate Change and Equitable Outcomes 10 3 Planning for Climate Change and Equitable
Outcomes
Local jurisdictions have a responsibility to ensure that the plan’s mitigation strategy complies with all applicable legal requirements related to civil rights, to ensure nondiscrimination. Such compliance can help achieve equitable outcomes through the mitigation planning process for all communities, including underserved communities and socially vulnerable populations.

To ensure that the planning process and outcomes of the local mitigation plan benefit the whole community, equity must be central in its development. Climate change increases the frequency, duration, and intensity of natural hazards, such as wildfires, extreme heat, drought, storms, heavy precipitation, and sea level rise. Communities are feeling the impacts of a changing climate now.

Respecting and leveraging the diversity of cultures in Santa Clara County ensures that mitigation planning is fair and equitable by applying a race and social justice framework to analyzing situations, evaluating options, and implementing solutions.

The Santa Clara County Office of Emergency Management (SCCOEM) has adopted the FEMA’s equity definition of “the consistent and systematic fair, just and impartial treatment of all individuals.” In addition, SCCOEM acknowledges that historically underserved communities and individuals are often overburdened by systemic injustices/disparities, and these are amplified during the disaster cycle including mitigation.

Therefore, the County of Santa Clara’s goal is to continue integrating equity into all aspects of emergency management by:
 Leveraging the Access and Functional Needs (AFN) and Cultural Competency Working Group that regularly meets with members of the entire Operational Area, including the community.  Involving members from a variety of groups represent the diverse community living in the County, as well as representatives from historically marginalized groups in the planning process.  Conducting outreach events that focus on the county’s diverse population and most vulnerable community members like people with access and functional needs.  Providing multilingual outreach and communication to residents of the County.  Adopting Communication, Maintaining Health, Independence, Safety, Support Services, and SelfDetermination, and Transportation (C-MIST) Framework. C-MIST is a function-based perspective composed of the five (5) functions that delineate areas where preparedness intervention can reduce disaster vulnerability and risk to the whole community.  Building, engaging, and sustaining partnerships with groups that have experienced inequities. For example, individuals experiencing communication, health, independence, safety, support services, self-determination, and transportation barriers during disasters.  Developing assessments and plans that prioritize assistance to those with the greatest needs and include vulnerable populations in the planning process.  Identifying needs and assets, as well as pre-existing vulnerability and resilience.  All community members can exercise their agency through free and informed choice(s).

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 3: Planning for Climate Change and Equitable Outcomes 11 Through these strategies, SCCOEM will continue to lay the foundation for closing gaps identified through lessons learned from previous EOC activations such as COVID-19, Wildfires, and Inclement Weather Episodes, and Active Shooter events that have impacted Santa Clara County.

Mitigation decisions and actions strive to provide benefit for all residents equally. SCCOEM Mitigation Program is designed to identify and remove social and institutional barriers that hinder or preclude people with disabilities and all those in the community historically subjected to unequal treatment from full and equal enjoyment of the programs, goods, services, activities, facilities, privileges, advantages, and accommodations provided. Additionally, during mitigation planning and applying for mitigation funding, the County will identify opportunities to increase equity and create new opportunities for the post-disaster state of the County.

An equitable community mitigation rests on the foundation of a “complete community” that applies equitable and fair practices in all the County’s planning and implementation. The concept demonstrates local government’s commitment to inclusion and fairness while managing a recovery process that links regional, state, and federal practices.

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4 Plan Update Approach
This plan update process had the following primary objectives:
 Secure grant funding.
 Form a planning group.
 Identify stakeholders.
 Establish a planning partnership.
 Define the Santa Clara County OA.
 Identify and coordinate with other agencies involved in hazard mitigation activities.  Review and integrate existing plans, policies, and programs.  Engage the public.

These objectives are discussed in the following sections.

4.1 Grant Funding
This planning effort was supplemented by a FEMA Hazard Mitigation Grant Program (HMGP) grant under DR-4569 California Wildfires. The County of Santa Clara Office of Emergency Management (OEM) was the sub-applicant for the grant. OEM applied in 2021 and was awarded the grant in 2022. It covered 75 percent of the cost for the development of this plan.

4.2 Formation of the Core Planning Team
Santa Clara County OEM hired IEM to assist with the development and implementation of the plan. The lead IEM planner reported directly to the Santa Clara County Operational Area Mitigation Program Manager and the project manager for the plan update. Meetings were held on a weekly and biweekly basis to discuss the plan update status, outreach and engagement strategies, and planning milestones. A Core Planning Team was formed to lead the planning effort, made up of the following members:
 Santa Clara County Office of Emergency Management
 Santa Clara County Office of Sustainability
 Santa Clara County Department of Planning and Development  IEM
This planning team—designated the Santa Clara County Operational Area Multijurisdictional Hazard Mitigation Plan (MJHMP) Core Planning Team (or the Core Planning Team)—coordinated regularly over the course of this project to track plan development milestones, brainstorm outreach and engagement strategies, and identify meeting content to help with development of the update. The Core Planning Team also consisted of members of the County Safety Element update, ensuring visibility between plans.

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4.3 Defining Stakeholders
For this planning process, “stakeholder” was defined as: any person or public or private entity that owns or operates facilities that would benefit from the mitigation actions of this plan, and/or has an authority or capability to support mitigation actions identified by this plan. This includes, but is not limited to, local and regional agencies involved in hazard mitigation activities, agencies that have the authority to regulate development, neighboring communities, representatives of businesses, academic, and other private organizations such as those that sustain community lifelines, and representatives of nonprofit organizations including community-based organizations that work directly with and/or provide support to underserved communities and socially vulnerable populations.

For the sake of clarity, when developing outreach materials, stakeholders were separated into two categories:
 Internal Stakeholders: Stakeholders identified and engaged by participants to enhance the planning process and the update of the MJHMP. These stakeholders are subject matter experts within the participating jurisdictions or special districts who impact or may be impacted by a mitigation action or policy. This included people in positions who had the authority to regulate development of the plan. These stakeholders informed the planning teams about specific topics and offered different points of view while providing data, reviewing the MJMP draft, attending planning workshops, and advocating for mitigation measures. Internal stakeholders for each planning partner are identified in the participant annexes in Volume 2.  External Stakeholders: Planning partners identified stakeholders outside their jurisdiction or special district who impact or can be impacted by a mitigation action or policy. These stakeholders were not necessarily involved in all stages of the planning process, but as subject matter experts, they informed the planning teams on specific topics and offered different points of view while providing data, reviewing the MJHMP draft, and advocating for mitigation measures.

At the beginning of the planning process, planning partners identified a list of stakeholders to engage during the development of the Santa Clara County Operational Area Hazard Mitigation Plan. The following stakeholders were invited to play a role in the planning process via email:

Table 3: External Stakeholders Invited to Be Involved in Planning Process Agency or Organization Point of Contact
American Red Cross Ann Herosy, Disaster Services
American Red Cross – Silicon Valley Chapter Ginny Ortiz, Disaster Program Manager Amateur Radio Emergency Service (ARES) Barton Smith, Coordinator Avenidas John Sink, Vice President
CADRE - Collaborating Agencies’ Disaster Relief
Effort
Marsha Hovey, Executive Director
California Office of Emergency Services (Cal
OES)
Victoria LaMar-Haas, Chief, Mitigation Planning
Division
Cal OES Brian Buckhout, Emergency Services Coordinator
California Department of Forestry and Fire
Protection
Edgar Orre, Division Chief
California Department of Transportation Shawn Casteel, Acting Senior Environmental Supervisor
Campbell Community Emergency Response
Team
Mark Dunkle, President

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Agency or Organization Point of Contact
Campbell Union School District Rosana Palomo, Director, Student Services Cattlemen’s Association Brent Kirk, President
City of East Palo Alto Melvin Gaines, City Manager
City of Menlo Park Justin Murphy, City Manager
Cooper-Garrod Estate Vineyards Bill Cooper, Vintner
Cupertino Sanitation District Benjamin Porter, District Manager Department of Homeland Security Staff, Transportation Security Administration Coordination Center
Department of Toxic Substances Claude Jemison, Regulator for Los Lagos Golf Course and SAP Center (former landfill and
cleanup site)
Department of Toxic Substances Sagar Bhatt, Regulator for Watson Park (former landfill)
Department of Toxic Substances Jovanne Villamater, Regulator for Vista Montana Parks
Department of Toxic Substances Julie Pettijohn, Manager for all regulatory sites except Watson Park
Downtown Streets Team Jim Rettew, Interim Executive Director Emergency Medical Services Michael Cubano, Duty Chief
Emergency Services Volunteer Representative Annette Glanckopft, Volunteer Emergency Services Volunteer Representative Esther Nigenda, Volunteer Federal Aviation Administration David Zakaski, Airport Tower Manager Fellowship Plaza Shreya Shah, Senior Project Manager
Foothill - De Anza Community College District Simon Pennington, Associate Vice President, College and Community Relations, Marketing, and
Communications
Foothill - De Anza Community College District Joel Cadiz, Executive Director, Facilities Foothill - De Anza Community College District
Police Department
Daniel Acosta, Police Chief
Gavilan College Jaime Mata, Interim Vice President,
Administrative Services
Gilroy Unified School District Aurelio Rodriguez Coordinator, Safety and Emergency Preparedness
Gilroy/Hollister California Highway Patrol Phil Cooper, Captain Google Katherine Williams, Corporate Communications
Hidden Villa farm Lukas Wiborg, Assistant Property Manager Intel Corporation Stacy Sher, Crisis Manager
Kaiser Permanente—Santa Clara Brendan Gadd, Safety Specialist Kaiser Permanente—Santa Clara Charles L. Smith, Support Services Administrator Life Moves Philip Dah, Opportunity Center Manager
Loma Prieta Volunteer Fire Department Alex Leman, Chief Los Altos Hills County Fire District J. Logan, General Manager

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Agency or Organization Point of Contact
Los Altos Hills County Fire District Captain (Ret.) Denise Gluhan Los Altos Hills County Fire District Eugenia Woods, Programs, Planning and Grants Manager
Los Altos School District Erik Walukiewicz, Assistant Superintendent, Business Services
Loma Prieta Resource Conservation District Dina Iden, Executive Director Morgan Hill Unified School District Carmen Garcia, Superintendent Moffett Field Ames Research Center, National
Aeronautics and Space Administration (NASA)
Anastasiya Maynich, Emergency Management
Specialist
National Weather Service, National Oceanic and
Atmospheric Administration (NOAA)
Brian Garcia, Meteorologist
Pacheco Pass Water District Neelima Palacherla, Executive Officer Palo Alto Chamber of Commerce Charlie Weidanz, Executive Director Palo Alto Medical Foundation Richard Stilleke, Director, Environmental Health and Safety
Palo Alto Planning and Transportation
Commission
Doria Summa, Vice Chair
Palo Alto Unified School District Mike Jacobs, Emergency Manager Pacific Gas and Electric (PG&E) Kevin Conant, Senior Public Safety Specialist Purissima Water District Phil Witt, General Manager
Purissima Water District Anthony Stoloski, Operations Manager Ravenswood Family Health Center Daisy Garcia, Associate, Disaster Preparedness and Project Management
Regional Water Quality Control Board Ava Castanha, Regulator, Environmental Innovation Center
Regional Water Quality Control Board Celina Hernandez, Regulator, Fire Training Regional Water Quality Control Board Alyx Karpowicz, Regulator, Roberts and Story Road Landfills
Regional Water Quality Control Board Vic Pal, Regulator, Singleton Landfill Rotating Safe Car Park Norman Puck, Program Director
San Francisquito Creek Joint Powers Authority Margaret Bruce, Executive Director San José Water John Tang, Vice President, Regulatory Affairs and Government Relations
Santa Clara County CERT President
Santa Clara County FireSafe Council Seth Schalet, Chief Executive Officer Santa Clara County FireSafe Council Amanda Brenner, Program Director, Hazardous Fuel Reduction
Santa Clara County FireSafe Council Dede Smullen, 2nd Vice President Santa Clara County Local Oversight Program Gerald O’Regan, Regulator for Fire Training Santa Clara County Local Oversight Program Joe Muzzio, Regulator for Fire Station at 1138 Olinder Road
Santa Clara County Local Oversight Program Shalom Marquardt, Regulator for Fire Station 8

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Agency or Organization Point of Contact
Santa Clara County Parks Don Rocha, Director
Santa Clara County Planning & Development Samuel Gutierrez, Principal Planner Santa Clara County Planning & Development Michael Alvarez, Deputy Director Santa Clara County Sheriff’s Office Neil Valenzuela, Commander, West Valley Patrol Division
Santa Clara University Tyler Masamori, Emergency Planning Manager Santa Clara Valley Open Space Authority Derek Newman, Manager, Field Operations Santa Clara Valley Open Space Authority Megan Robinson, Supervising Open Space Technician
Santa Cruz County David Reid, Director, Office of Emergency Management
Saratoga Amateur Radio Association Jack Griswold, President Saratoga Area Senior Coordinating Council Tylor Taylor, Executive Director Saratoga CERT Charles Rader, Volunteer Lead
Saratoga Fire Protection District Commissioner Joseph Long Jr.

Saratoga Fire Protection District Commissioner Ernest Kraule Saratoga Fire Protection District Commissioner Eugene Zambetti Saratoga Fire Protection District Trina Whitley, Business Manager Saratoga Retirement Community Sarah Stel, Executive Director Silicon Valley Animal Control Authority (SVACA) Heidi Springer, Executive Assistant Silicon Valley Clean Energy Girish Balachandran, Executive Director San José Fire Department, San José Mineta
International Airport
Brendan Buller, Battalion Chief
San José Police Department, San José Mineta
International Airport
Jason Pierce, Lieutenant
Spring Valley Volunteer Fire Department Mike Hacke, Chief St. Louise Hospital (Santa Clara County Hospital
System)
Geoff Tull, Emergency Management Coordinator
Stanford Healthcare Kathy Harris, Emergency Manager
Stanford Healthcare Laura Jackson, Senior Manager, Office of Emergency Management
Stanford Healthcare Monica Plumb, Project Coordinator, Office of Emergency Management
Stanford Healthcare Taylor Wyatt, Project Coordinator, Office of Emergency Management
Stanford University Cody Hill, Associate Director, Stanford Resiliency and Emergency Response
Stanford University Board of Trustees Staff, Board of Trustees Office Stanford University Office of Emergency
Management
Keith Perry, Assistant Director and Emergency
Manager
Stanford University, IT Facilities, Infrastructure,
and Resilience
Matthew Ricks, Senior Director

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Agency or Organization Point of Contact
Stanford University, Water Resources and Civil
Infrastructure
Tom Zigterman, Senior Director
Stanford University/Real Estate Mark Smith, Manager
Stanford University/Real Estate Ramsey Shuayto, Director, Asset Management The Villas Scott Clawson, Manager
Valley Water Flood Information Team Greg Meamber, Senior Engineer Vista Center for the Blind and Visually Impaired Karae Lisle, Chief Executive Officer West Valley Clean Water Program Authority Sheila Tucker, Executive Director West Valley College Stephanie Kashima, President
West Valley Sanitation District Jon Newby, District Manager Westwind Barn Tori Dye, Barn Manager

4.4 Establishment of the Planning Partnership
Santa Clara County OEM opened this planning effort to all eligible local governments and special districts within the OA. Each jurisdiction or special district wishing to join the planning partnership was asked to provide a “letter of intent to participate” that designated a point of contact and confirmed the organization’s commitment to the process and understanding of expectations. All planning partners provided this letter of intent. The planning partners covered under this plan are listed below.

Table 4: Planning Partner Main Points of Contact
Planning Partner Main Point of Contact
County of Santa Clara Dr. Parastou Najaf, Senior Emergency Manager – Mitigation/Recovery, Santa Clara County Office of Emergency Management
City of Campbell Dan Livingston, Captain of Support Services Division, Police Department
City of Cupertino Meredith Gerhardt, Emergency Management Analyst, Office of Emergency Management
City of Gilroy Andrew Young, Emergency Services and Volunteer Coordinator, Office of Emergency Services
City of Los Altos Kathryn Krauss, Captain of Operations, Police Department Town of Los Altos Hills Ann Hepenstal, Emergency Preparedness Consultant, Town of Los Altos Hills
Town of Los Gatos Nicolle Burnham, Director, Parks and Public Works Department
City of Milpitas Toni-Lynn Charlop, Manager, Office of Emergency Services City of Morgan Hill Jennifer Ponce, Coordinator, Office of Emergency Services City of Mountain View Robert Maitland, Emergency Services Coordinator, Office of Emergency Services
City of Palo Alto Nathaniel Rainey, Emergency Services Coordinator, Office of Emergency Services

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Planning Partner Main Point of Contact
City of San José Jay McAmis, Deputy Director, Office of Emergency Management
City of Santa Clara Jennifer Guzman, Emergency Management Analyst, Office of Emergency Services
City of Saratoga Crystal Bothelio, Assistant City Manager, City Manager’s Department
City of Sunnyvale Daniel Moskowitz, Lieutenant, Office of Emergency Services, Department of Public Safety
Midpeninsula Regional Open Space
District
Brandon Stewart, Land and Facilities Department Manager, Midpeninsula Regional Open Space District
Santa Clara County Fire Department Louay Toma, Senior Emergency Manager, Santa Clara County Fire Department
Santa Clara Valley Water District Juan Ledesma, Program Administrator Supervisor, Office of Emergency Services
One-on-one planning meetings were held with planning partners throughout the planning process. A total of 43 individual meetings were held with plan participants to gather information and to provide guidance for the jurisdictions and special districts throughout the planning stages. Each meeting is described in Table 5.

Table 5: One-on-One Meetings with Planning Partners
Planning Partner Date Discussion Topic(s)
City of Campbell February 13, 2023  Planning process contacts  Capabilities assessment
May 15, 2023  Planning documentation review
City of Cupertino February 6, 2023  Planning process contacts  Capabilities assessment
April 20, 2023  Mitigation strategy
City of Gilroy February 14, 2023  Planning process contacts  Capabilities assessment
City of Los Altos February 14, 2023  Planning process contacts  Capabilities assessment
April 27, 2023  Capabilities assessment
 Mitigation strategy
May 9, 2023  Planning documentation review
City of Milpitas March 17, 2023  Planning process contacts  Capabilities assessment
 Risk assessment
May 1, 2023  Risk assessment
 Mitigation strategy
City of Morgan Hill February 14, 2023  Planning process contacts  Capabilities assessment

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Planning Partner Date Discussion Topic(s)
City of Mountain View January 31, 2023  Planning process contacts  Capabilities assessment
March 15, 2023  Risk assessment
April 13, 2023  Mitigation action items
May 1, 2023  Mitigation strategy
City of Palo Alto February 7, 2023  Planning process contacts  Capabilities assessment
 Planning process timeline
City of Santa Clara February 8, 2023  Planning process contacts  Capabilities assessment
 Planning process timeline
March 16, 2023  Risk assessment with local planning team March 17, 2023  Risk assessment with water and sewer team March 26, 2023  Mitigation strategy
May 10, 2023  Planning documentation review
City of San José February 13, 2023  Planning process contacts  Capabilities assessment
April 27, 2023  Capabilities assessment
 Mitigation strategy
May 16, 2023  Planning documentation review
City of Saratoga February 9, 2023  Planning process contacts  Capabilities assessment
March 14, 2023  Risk assessment
City of Sunnyvale January 26, 2023  Planning process contacts  Capabilities assessment
March 3, 2023  Risk assessment
April 7, 2023  Risk assessment
 Mitigation strategy
Midpeninsula
Regional Open
Space District
March 6, 2023  Planning process contacts
 Capabilities assessment
 Risk assessment
 Planning process timeline
Santa Clara County
and Santa Clara
County Fire
Department*
February 10, 2023  Planning process contacts
 Capabilities assessment
March 2, 2023  Planning process contacts
 Capabilities assessment
March 8, 2023  Capabilities assessment
 Risk assessment
March 28, 2023  Capabilities assessment
 Risk assessment
 Mitigation strategy

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Planning Partner Date Discussion Topic(s)
Santa Clara Valley
Water District
January 23, 2023  Annex layout and contents
 Community Rating System
February 21, 2023  Community Rating System
March 13, 2023  Community Rating System
April 21, 2023  Mitigation strategy
 GIS and mapping
Town of Los Altos
Hills
March 17, 2023  Risk assessment
April 25, 2023  Risk assessment
 Mitigation strategy
June 20, 2023  Annex draft review
Town of Los Gatos February 13, 2023  Planning process contacts  Capabilities assessment
April 27, 2023  Capabilities assessment
 Mitigation strategy
*Santa Clara County and Santa Clara County Fire Department held meeting together due to shared staff and resources.

Figure 1: Planning Partners Meeting

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Figure 2: Planning Partners Mitigation Strategy Meeting

4.5 Defining the Planning Area
The defined planning area for this update has been defined as the Santa Clara County Operational Area (OA). The OA is defined as the unincorporated county and incorporated cities within the geographical boundary of Santa Clara County. Relevant OA characteristics are described in Section 5. The City of Monte Sereno did not actively participate in this MJHMP and does not have a planning partner annex; however, information and data related to the city are included throughout the plan as appropriate and relevant.

4.6 Review of Existing Programs
Hazard mitigation planning must include review and incorporation, if appropriate, of existing plans, studies, reports, and technical information (44 CFR, Section 201.6(b)(3)). Section 5.9 of this plan provides a review of laws and ordinances in effect within the OA that can affect hazard mitigation actions. In addition, the following programs can affect mitigation within the OA:
 California Fire Code.
 2016 California Building Code.
 California State Hazard Mitigation Forum.
 Local Capital Improvement Programs.
 Local Emergency Operations Plan.
 Local General Plans.
 Housing Element.
 Safety Element (prior and 2023 draft components).
 Community Wildfire Protection Plan (2016 version and components of the 2023 draft).  Local Zoning Ordinances.

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 Local Coastal Program Policies.

An assessment of all planning partners’ regulatory, technical, and financial capabilities to implement hazard mitigation actions is presented in the individual planning partner-specific annexes in Volume 2.

Many of these relevant plans, studies and regulations are cited in the capability assessment.

4.7 Public Involvement
Broad public participation in the planning process helps ensure that diverse points of view about the OA’s needs are considered and addressed. Additionally, the plan must document how the public had an opportunity to be involved in the planning process, including underserved communities and vulnerable populations within the planning area were provided an opportunity to be involved. The public must have opportunities to comment on disaster mitigation plans during the drafting stages and prior to plan approval (44 CFR, Section 201.6(b)(1)).

4.7.1 Strategy
The planning team developed a robust public outreach process within the very short project timeline, attempting to reach as many Santa Clara County community members and stakeholders as possible through the following activities:
 Development of a public outreach plan approved by the Core Planning Team.  Partner with planners updating the Safety Element and Community Wildfire Protection Plan planning processes to expand public outreach efforts.
 Attendance at advertised public outreach events and virtual meetings with live interaction.  Development and advertisement of a public survey posted on the SCCOEM’s webpage to collect pertinent information from residents and the business community.  Publication of the survey in Santa Clara County’s most spoken languages: English, Spanish, Chinese, Tagalog, and Vietnamese.
 Use of social media, such as Nextdoor, Facebook, and Twitter to publicize the survey.

Stakeholder Outreach
Stakeholders are the individuals, departments, agencies, and jurisdictions that have a vested interest in the recommendations of the hazard mitigation plan. The effort to include stakeholders in this process included stakeholder participation on the Steering Committee. The following federal, state, regional, and local stakeholders also played a role in the planning process:
 FEMA Region IX provided planning guidance throughout the planning process.  The California Office of Emergency Services (Cal OES) provided planning guidance throughout the planning process. Cal OES also reviewed the draft and final version of the MJHMP as part of the hazard mitigation planning process required by DMA.  Many local external stakeholders, including state agencies, local agencies, universities, and nonprofit organizations, were given the opportunity to review the draft plan and provide input. A list of these stakeholders is included in Table 3.

The strategy to involve the public and external stakeholders in this plan include the following:
 Utilize a survey to determine if the public’s perception of risk and support of hazard mitigation has changed since the initial planning process.

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 Utilize social media and local media to share information about the MJHMP process and inform OA citizens about opportunities to participate.
 Identify and involve a comprehensive range of OA stakeholders.  Partner with planners updating both the Safety Element and the Community Wildfire Protection Plan to expand public outreach efforts.

Public Survey
The planning team relied on the community survey (available in English, Spanish, Tagalog, Chinese, and Vietnamese) as the primary method for gathering information and feedback from the public. The secondary method was multiple in-person combined planning meetings which participants were introduced to hazard mitigation and invited to take the survey. The survey was approved by the Core Planning Team and was available to complete via the Santa Clara County Office of Emergency Management’s website. Flyers were also posted around the County and on participating jurisdiction’s official websites and social media pages.

Figure 3: Picture of Public Survey Announcement

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Figure 4: Public Survey Media Announcement
The survey included 35 questions to:
 Gauge the public’s perception of risk and identify what citizens are concerned about;  Identify the best ways to communicate with the public;  Determine the level of public support for the different mitigation strategies; and  Understand the public’s willingness to invest in hazard mitigation.

Social Media
At the beginning of the plan development process, a website hosted on the Santa Clara County OEM main website was utilized to keep the public posted on plan development milestones and to solicit relevant input. The website was publicized in all press releases and public meetings. Information on the plan development process, the survey, and phased drafts of the plan was made available to the public on the site throughout the process. Santa Clara County OEM intends to keep a website active after the plan’s completion to keep the public informed about successful mitigation projects and future plan updates.

The website can be accessed at this link: https://emergencymanagement.sccgov.org/multijurisdictional-hazard-mitigation-plan-mjhmp.

Many of the participating local jurisdictions also promoted the website on social media and used social media platforms to share public meeting information, notice of the public survey, and notice of the public comment period. Valley Water, for example, posted to Twitter five times and Facebook 4 times as part of a multi-prong strategy. An example of the social media outreach is provided below.

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Figure 5: City of Campbell Social Media Outreach
Local Media and Press Releases
The Planning Team conducted a wide range of outreach activities in local media. The County developed three key messages to highlight the significance of the Public Survey Period:

1. Announcement of the Public Survey Period: Informing the community about the survey’s availability.

2. Planning for the Future: Emphasizing the importance of proactive hazard mitigation planning.

3. Your Participation Matters: Encouraging community members to participate and contribute to the planning process by taking the survey.

During the Public Survey Period for the MJHMP, Santa Clara County disseminated one press release to the various media outlets and utilized a specific media monitoring service to report media coverage for the MJHMP. Unfortunately, despite the County’s best efforts, no major media outlets covered the event.

However, Sing Tao Dailey, a prominent Chinese media outlet, published the information on their website on April 17, 2023. This media outlet boasts a wide-reaching presence across the United States, maintaining offices in major markets which includes New York, Los Angeles, and San Francisco. The press release was also published to the Office of Emergency Management’s website as part of the Newsroom page.

Valley Water also reached out to communities via local media, including Chinese News, El Observador, Murcury News, Metro, Nextdoor, and Vietnam Daily.

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Information was posted to the County’s social media sites including Facebook, Instagram, Twitter, as well as the Department of Planning and Development’s website and the County’s main website during the public survey period. To amplify public messaging, the County encouraged key stakeholders, including the Operational Area Joint Information System, the Access and Functional Needs & Cultural Competency Work Group, and the Operational Area Emergency Managers to amplify messaging with their served community members.

To simplify access to the survey and increase participation, the County established a user-friendly vanity URL. This URL received significant traction, directing 74% of community members to the Hazard Mitigation Webpage, resulting in 880-page views and 767 visits. Additionally, 81% of users who accessed the Hazard Mitigation Page were successfully redirected to the actual survey page. The Hazard Mitigation page was the second most popular site for the period.

The strategic use of local communication channels successfully enhanced community engagement, ensuring a more robust Multi-Jurisdictional Hazard Mitigation Plan.

Joint MJHMP Outreach
Plan integration was considered throughout the development of a public outreach approach for this plan update. As the Safety Element was being updated at the same time as the Santa Clara County Operational Area HMP, the Core Planning Team members coordinated to include hazard mitigation planning components during outreach for the Safety Element. At this meeting, members of the public were presented with interactive boards and polling questions to gauge their hazard concerns, personal preparedness measures, public outreach and education needs, and support for common infrastructure enhancements. The Hazard Mitigation Plan update was discussed, and the public was provided with information on hazard mitigation and hazard mitigation planning including a link to the public survey. This meeting was conducted at the Campbell Community Center, targeting vulnerable populations in the City of San Jose and central Santa Clara valley. The county geographically designed this approach to ensure that those residence who could not travel to the South County community outreach event in Gilroy (mentioned below) still had an opportunity to have their voices heard. Valley Water had staff representation in the audience to respond to and capture inquiries pertaining to Valley Water’s jurisdictions. More than 40 residents from across the county, including vulnerable pockets in the City of San Jose and the Santa Cruz mountain range, interacted and worked with the MJHMP to voice their concerns.

In determining which vulnerable communities to target for outreach, planning partners referenced the California Hazard Exposure and Social Vulnerability map, Figure 6 below. Two underserved or socially vulnerable communities were identified according to their estimated hazard exposure and social vulnerability. The largest area in San Jose is east of Highway 87 and a much smaller area is in South Santa Clara County, specifically the City of Gilroy. In addition, by using the CalEMA GIS dashboard, these two areas are also recognized for having a median household income of less than 80% of the statewide average and for having significant earthquake ground shaking potential.

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Figure 6: Hazard Exposure and Social Vulnerability Map for Santa Clara Valley The County also actively facilitated meetings and coordinated outreach between the team working on the HMP and the Community Wildfire Protection Plan (CWPP). Like the HMP, the CWPP includes recommendations for mitigation measures across the OA. It also includes annexes for the many of the same planning partners which highlight their unique wildfire history and considerations. These similarities presented a valuable opportunity for the two teams to solicit input from the public together. Four joint inperson Public Outreach meetings were conducted in remote, access and functional needs (AFN) areas of the incorporated County as well as an in-person meeting in the Gilroy/South County area where there are pre-identified vulnerable populations. All were welcome to attend. For those that could not make it in person, an additional online outreach meeting was held.

Draft Plan Final Public Comment Period
A public comment period was conducted to allow the public to provide feedback on the proposed draft of the plan prior to submittal to Cal OES for pre-adoption review and approval. This public comment period ran for 14 days from July 14 to July 28, 2023. The draft plan was shared by participating jurisdictions via their social media sites and emails to external stakeholders. The posted plan was accompanied by a narrative explaining to the public the purpose and content of the plan and was available to view on the County’s website.

The Planning Team received 17 comments from the public during the comment period. These comments were reviewed by the Planning Team and incorporated in the plan as appropriate.

4.7.2 Public Involvement Results
Survey Results
The survey received 588 responses. There were 576 responses to the English survey, 10 responses to the Chinese survey, and 2 responses to the Spanish survey. The use of multi-lingual outreach material proved to be valuable in providing the opportunity for more participation and in receiving a

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broader range of feedback. The results of the survey were presented to the planning partners and will be used in all future decisions making regarding mitigation, risks, and hazards. The survey results regarding respondent’s concern for hazards are summarized in Appendix A of this volume.

Public Outreach Events
As mentioned, many joint planning efforts occurred between the Santa Clara County MJHMP, Safety Element, and Community Wildfire Protection Plan. This is the first time in Santa Clara County history that this kind of planning effort and coordination has occurred. There were several public meetings for each planning initiative, and each meeting included presentations about the Multijurisdictional Hazard Mitigation Plan.

By engaging the public both virtually and in person, the concept of mitigation was widely shared, and the public was provided the opportunity to review the draft plan. Participants at each meeting were encouraged to participate via the public survey. Table 6 summarizes each public outreach meeting that occurred across the OA.

Recordings of each meeting can be found at https://sccfiresafe.org/cwpp/ Figure 7: Public and Stakeholder Meeting with 99 Participants

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Figure 8: Public and Stakeholder Meeting with 104 Participants Table 6: Summary of Public Outreach
Date Summary of Outreach
November 10,
2022
MJHMP presentation and invitation for public comment and feedback at the joint Safety Element Virtual Town Hall (virtual)
December 6,
2022
MJHMP presentation and invitation for public comment and feedback at the joint CWPP Community Outreach Meeting Campbell (in-person)
 59 fliers distributed, 24 individual risk assessments conducted, 75+ contacts made regarding the plan
December 7,
2022
MJHMP presentation and invitation for public comment and feedback at the joint CWPP Community Outreach Meeting San Jose (in-person)
December 13,
2022
MJHMP presentation and invitation for public comment and feedback at the joint CWPP Community Outreach Meeting Milpitas (in-person)
December 15,
2022
MJHMP presentation and invitation for public comment and feedback at the joint CWPP Community Outreach Meeting Morgan Hill (in-person) December 15,
2022
MJHMP presentation and invitation for public comment and feedback at the joint Safety Element CARAS South County Community Listening Meeting (in-person) March 15,
2023
MJHMP presentation and invitation for public comment and feedback at the joint Safety Element Listening Session
June 14-28, 2023 Draft MJHMP published online and a public comment period was in place for two weeks. Comments were considered and implemented where applicable.

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Draft MJHMP Public Comment Period
During the development of the MJHMP, the public had the opportunity to review the Draft and make final comments. Every participating jurisdiction advertised this public comment period by using multiple online resources, including official social media accounts, websites, and online newsletters. These comments were taken into consideration and implemented where applicable.

Figure 9: Samples of Public Comment Period Advertisements Public Representation
In addition to directly providing the public the opportunity to comment on the plan, the Santa Clara County Access and Functional Needs and Cultural Competency Working Group which represents tens of community and faith-based organizations within the SCC operational area were consulted on the plan and were able to provide feedback based on the populations they serve. Approximately 100 non-profits and VOAD members participate in the AFN and Cultural Competency Working Group. SCC also has representation from community centers and two consulate generals. In addition, there are also advocates who do not have an affiliation but are Santa Clara County residents and provide input on LGBTQ+ and Disability topics. Some of the organizations include but are not limited to San Andreas Regional Center, Immigrant Info Services, Vista Center for the Blind, American Red Cross, Parents Helping Parents, Lighthouse. In general, the direct interaction and represented voices shared similar sentiments in concern for specifically the extreme heat and wildfire hazard, community preparedness, and education and outreach activities. Therefore, prioritization of the wildfire hazard, and the corresponding mitigation actions, along with high attention to public outreach and education efforts informed the many such related mitigation actions in the plan.

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4.8 Plan Development Chronology and Milestones
Table 7 summarizes important milestones in the plan update process.

Table 7: Plan Development Chronology and Milestones
Date Event Description
December
8, 2022
Initial meeting with Core Planning
Team
 Planning groups
 IEM project staff
 Project phases
 Proposed workshop schedule
 Administration and logistics
December
14, 2022
Kick off meeting with planning
partners
 Introductions
 IEM project staff
 Planning groups
 Mitigation overview
 Mitigation planning benefits
 Intent of plan update
 Plan participants
 Hazards covered
 Updated FEMA requirements
 Planning expectations
 Project phases
 County planning efforts underway
 Plan integration opportunities
 Stakeholder identification
 Use of SharePoint
January 18,
2023
Community Capabilities Review
Workshop with planning partners
 Planning groups
 Planning process contacts
▪ Local planning teams
▪ Internal stakeholders
▪ External stakeholders
 Capabilities assessment
 National Flood Insurance Program (NFIP)
 Use of SharePoint
February
15, 2023
Risk Assessment Workshop with
planning partners
 Project phases
 Public outreach and documentation
 Hazus
 GIS
 Community Rating System (CRS)
 Risk assessment
 Planning documents
 Risk ranking
March 15,
2023
Stakeholder Engagement
Workshop #1
 Workshop goals
 Hazard mitigation planning
▪ Overview

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Date Event Description
▪ Planning process
 Project phases
 Mitigation action items
 Feedback on data sources
April 3,
2023
Stakeholder Engagement
Workshop #2
 Workshop goals
 Multijurisdictional hazard mitigation plan recap
 Mitigation strategy
 Mitigation action items
 Funding sources
 Mitigation integration
April 3,
2023
Mitigation Strategy Workshop with
planning partners
 Mitigation strategy
 Mitigation projects working group
 2017 mitigation strategy
 Review of 2017 actions
 New action items
 Mitigation incorporation
April 4,
2023
Public survey published on County
of Santa Clara Office of
Emergency Management website
Thirty-five question survey published at
https://emergencymanagement.sccgov.org/pa
rtners/hazard-mitigation-program
April 18,
2023
Mitigation Strategy Working Group
Meeting
 Working group expectations
 Review of 2017 MHMP goals and objectives
 Review of 2017 MHMP projects
 Discussion of the current gaps in identifying
projects and accessing funding
May 19,
2023
Public survey closed Total of 588 responses received: 576 in English, 10 in Chinese, and 2 in Spanish.

June 2,
2023
Planning process wrap up meeting
with planning partners
 Public survey results summary
 Implementation
 Monitoring and evaluation
 Maintenance
 Adoption
 Draft review
 Draft plan publicity for public and stakeholders
July 13,
2023
Draft plan published on County of
Santa Clara Office of Emergency
Management website for public
and stakeholder review
Public comment period was open for two weeks
to give the public a chance to review the Draft
and make comments.

September
25, 2023
Plan submittal to Cal OES Final draft plan submitted to Cal OES for review and approval.

January 16,
2024
Plan submittal to FEMA Final draft plan submitted to FEMA for review and approval.

Plan Approvable Pending
Adoption (APA) by FEMA.

FEMA to provide APA Letter once they approve
the final draft plan.

February 8,
2024
First planning partner adopts
approved plan.

All participants must formally adopt the plan. The
five-year lifecycle begins with the first adoption.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 33 5 Santa Clara County Operational Area Profile

5.1 Geographic Overview
The Santa Clara County Operational Area is in north-central California in the southern portion of the San Francisco Bay area (see Figure 9). With its numerous natural amenities and one of the highest standards of living in the country, the OA has long been considered one of the best areas in the United States in which to live and work. The county is also referred to as “Silicon Valley.” The Santa Clara County OA has a total area of 1,312 square miles. With a diverse population of more than 1.9 million residents,6F
7 it is one of the largest counties in the state and encompasses 15 incorporated cities.

San José is the largest city, with just over 1 million people,7F 8 followed by Sunnyvale and Santa Clara; the
west valley bedroom communities of Los Altos, Los Altos Hills, Los Gatos, Monte Sereno, and Saratoga; the high-tech communities of Campbell, Cupertino, Mountain View, and Palo Alto; industrial Milpitas, and the south county suburban expansion/rural interface areas of Gilroy, Morgan Hill, and their surrounding unincorporated areas. A significant portion of the county’s land area is unincorporated ranch and farmland.

The OA has a rich culture of ethnic diversity, artistic endeavors, sports venues, and academic institutions.

Numerous public and private golf courses are located throughout the OA and Santa Clara County operates 28 parks covering more than 50,000 acres, including lakes, streams, and miles of hiking and biking trails. The OA is home to three major universities—Stanford University, Santa Clara University, and San José State University—as well as several community colleges.

5.2 Historical Overview
The early inhabitants of the area now known as Santa Clara County were the indigenous Ohlone people, thought to occupy the area at least 1,000 years before Spain began to colonize California in the 18th century.

Spanish settlers established the Santa Clara Valley’s first mission and pueblo in Santa Clara and San José, respectively, and governed “El Llano de Los Robles” (Plain of the Oaks), until the Mexican Revolution led to Mexican control from the 1820s through 1840s. In 1850, California was admitted into the United States, and Santa Clara County was incorporated as one of the state’s original 27 counties.

Deriving its name from Mission Santa Clara, the county originally included much of what was Washington Township (part of Union City and Fremont) in what is now Alameda County. The current county boundaries were set in 1853 when Alameda County was established.

From 1850 to 1870, ranchers made a transition from raising cattle and sheep to cultivating hay and grain.

French immigrants planted the first vineyards. Mercury mining flourished. California’s first colleges were founded in Santa Clara County and the coming of the railroad produced a small boom in real estate. 7 United States Census Bureau. (2020). Quick Facts: Santa Clara County. https://www.census.gov/quickfacts/santaclaracountycalifornia 8 United States Census Bureau. (2020). Quick Facts: San José City. https://www.census.gov/quickfacts/fact/table/sanjosecitycalifornia,santaclaracountycalifornia/PST045222

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 34 Figure 10: Santa Clara County Operational Area (Planning Area) After 1870, orchards began displacing grain fields and vineyards. The Santa Clara Valley became the world’s leading producer of canned fruit and processed dried fruit. By the end of the 19th century, wealthy San Franciscans, such as Leland Stanford and James Lick, established farms and summer homes in the county.

Santa Clara County remained pastoral until World War II, when many people gravitated to California to work in war-related industries. To accommodate the growing population, mass-produced housing spread across the Santa Clara Valley, and agricultural land was subdivided and developed for housing. Like much of the rest of the United States in the decades immediately following the war, development in the county shifted from largely agricultural to largely suburban.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 35 At the same time, technology companies began to flourish in Santa Clara County, with significant support and encouragement from Stanford University. The Stanford Industrial Park, established in 1951, later became the Stanford Research Park and provided space for companies such as Hewlett-Packard, Eastman Kodak, General Electric, and Lockheed. Related companies began to form around the region, and by the 1970s Santa Clara County and surrounding areas became known as a center of hightechnology development. The term Silicon Valley was coined in 1971, referring to the high concentration of companies in the area that are involved in making silicon semiconductors and the computers that rely on them. Technology industries remain central to the area’s economy to this day.

5.3 Major Past Hazard Events
Presidential disaster declarations are typically issued for hazard events that cause more damage than state and local governments can handle without assistance from the federal government. A presidential disaster declaration puts federal recovery programs into motion to help disaster victims, businesses, and public entities. Some of the programs are matched by state programs. Santa Clara County has experienced 20 events (14 major disaster declarations, three emergency declarations, two fire management assistance declarations, and one fire suppression declaration) since 1950 for which presidential disaster declarations were issued. These events are listed in Table 8.

Table 8: Presidential Disaster Declarations8F
9 Type of Event FEMA Disaster
Number* Date
Severe Winter Storm DR-3592 03/10/2023
Severe Winter Storms, Flooding, Landslides, and Mudslides DR-4683 January 14, 2023 Severe Winter Storms, Flooding, and Mudslides EM-3591 January 9, 2023 Wildfires DR-4558 August 22, 2020
SCU Lightning Complex Fire DR-5338 August 21, 2020
COVID-19 Pandemic DR-4482 March 22, 2020
COVID-19 EM-3428 March 13, 2020
Severe Winter Storms, Flooding, and Mudslides DR-4308 April 1, 2017 Severe Winter Storms, Flooding, and Mudslides DR-4301 February 14, 2017 Summit Fire DR-2766 May 22, 2008
Wildfires DR-3287 06/28/2008
Croy Fire FS-2465 September 25, 2002
Severe Winter Storms and Flooding DR-1203 February 9, 1998 Severe Storms, Flooding, Mudslides, and Landslides DR-1155 January 4, 1997 Severe Winter Storms, Flooding Landslides, and Mud Flow DR-1046 March 12, 1995 Severe Winter Storms, Flooding, Landslides, and Mud Flows DR-1044 January 10, 1995 Severe Freeze DR-894 February 11, 1991
Loma Prieta Earthquake DR-845 October 18, 1989
Severe Storms and Flooding DR-758 February 21, 1986
Grass, Wildlands, and Forest Fires DR-739 July 18, 1985 9 Federal Emergency Management Agency. (2023). Declared Disasters. https://www.fema.gov/disaster/declarations

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 36 Type of Event FEMA Disaster
Number* Date
Coastal Storms, Floods, Slides, and Tornadoes DR-677 February 9, 1983 Severe Storms, Flood, Mudslides, and High Tide DR-651 January 7, 1982 Drought EM-3023 January 20, 1977
* DR = Disaster Declaration; EM = Emergency Declaration; FM = Fire Management; FS = Fire Suppression Review of these events helps to identify targets for risk reduction and ways to increase a community’s capability to avoid large-scale events in the future. Still, many natural hazard events do not trigger federal disaster protocol but have significant impacts on their communities. These events are also important to consider in establishing recurrence intervals for hazards of concern. Additional information about previous hazard events is included in Section 6 of this plan.

5.4 Physical Setting

5.4.1 Geology and Topography
The OA’s topography is characterized by its location in the southern San Francisco Bay area. The Santa Clara Valley runs the entire length of the county from north to south, ringed by the rolling hills of the Diablo Range on the east, and the Santa Cruz Mountains on the west. Salt marshes and wetlands lie in the northwestern part of the county, adjacent to the waters of San Francisco Bay.

5.4.2 Soils
Prior to 1950 and as far back as the late 1800s, Santa Clara Valley was the scene of a vibrant and productive agriculture industry. Many of the soils of the Santa Clara Valley are alluvial, deposited on fans or floodplains within the valley. The young, deep soils (Elder, Elpaloalto, Still, Stevens Creek, Landelspark, Botella, and Campbell) are naturally very fertile. Field crops were cultivated on the lower parts of the valley, and orchards spanned from the hills east of Milpitas and San José across the valley to Los Altos and Palo Alto. With the introduction of the electric water pump in the early 20th century, irrigation water from the plentiful ground-water supply became readily available on farms, increasing productivity.

The Santa Clara Valley became widely known for the production of high-quality orchard fruits, which were shipped across the United States.

Dams were constructed on major streams to store irrigation water and control flooding. As groundwater was rapidly pumped from a depth of several hundred feet, subsurface materials compacted which led to land subsidence. Subsidence damaged pipes and other in-ground structures, and levees were required to block tidewater from entering subsided land. The benefit of this control of streams and pumping of groundwater was a valley relatively free from flooding and high groundwater, an ideal condition for the rapid urban expansion that followed.

After World War II, urban growth in the San Francisco Bay area began to expand down to the south end of the bay and into the Santa Clara Valley. After 1950, the pace of development quickened, and subdivisions began to spring up. The first wave of development occurred on the soils along the El Camino Real corridor, where the alluvial fans were relatively level, with slopes of 2 percent or less. Development exploded in the 1960s and topsoil was moved to house lots from the street areas. This type of subdivision construction continued until about 1980, when more shaping of house lots to control drainage began. By 1980, home construction had started to slow because many of the level areas fit for construction were now already developed.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 37 After 1980, subdivision development moved up areas of alluvial fans and greater slopes, and lot-shaping became more common. After 1990, development moved into steep areas at the edge of the valley and the foothills. Soil disturbance can be severe in these areas, with more than 5 feet of cuts or fills.

Fills may consist of materials from several feet below the soil surface, have a high content of clay or fragments, and be low in organic matter and fertility. Cut areas may have subsoil materials at the surface, which also may have a high content of clay or fragments and be low in organic matter and fertility. Many residents have modified the soil surface texture in garden areas with sandy materials and mulches. In areas of the basin soils (Hangerone, Clear Lake, and Embarcadero), clay surface and subsurface textures and slow internal drainage due to a high clay content are problems for gardens, ornamental plants, and lawns.9F
10 5.4.3 Climate
Table 9 summarizes normal climate date from 1981 through 2022 at the National Climatic Data Center weather station at San José. The Mediterranean climate of the OA remains temperate year-round due to the area’s geography and its proximity to the Pacific Ocean. The area is warm and dry much of the year.

Rarely is the humidity uncomfortable, and the thermometer seldom drops below freezing. Rain is generally limited to winter and snow to the tops of local mountains.

Table 9: Normal Precipitation and Temperatures in the Operational Area, 1981–202210F 11 Months Mean Precipitation
(inches)
Minimum
Temperature (°F)
Maximum
Temperature (°F)
January 2.65 32 68
February 2.56 35 74
March 2.28 38 79
April 0.91 41 87
May 0.41 46 91
June 0.10 50 97
July 0.01 53 95
August 0.02 54 96
September 0.16 51 95
October 0.66 45 90
November 1.55 37 77
December 2.35 32 68
Annual 13.39 30 100
10 United States Department of Agriculture. (2015). Supplement to the Soil Survey of Santa Clara. https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soil/soil-science 11 National Oceanic and Atmospheric Administration. (n.d.). Climate Data Online. https://www.ncei.noaa.gov/cdo-web/

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5.5 Development Profile

5.5.1 Land Use
Table 10 shows current land use for unincorporated Santa Clara County; complete land use data was not available for municipalities in the OA. Land use information is analyzed in this plan for each identified hazard that has a defined spatial extent and location.

For hazards that lack this spatial reference, the information in the table serves as a baseline estimate of land use and exposure. The distribution of land uses for the unincorporated county will change over time.

Table 10: Unincorporated County Land Use
Type of Land Use Area (acres) Percentage of Total Area
Agricultural 33,355.5 5.53
General / Institutional 5,381.3 0.89
Open Space 548,603.4 90.88
Low Density Residential 15,988.7 2.65
High Density Residential 68.6 0.01
Commercial 161.8 0.03
Industrial 85.0 0.01
Total 603,644.5 100.00

5.5.2 Critical Facilities, Infrastructure, and Assets
Critical facilities and infrastructure are those that are essential to the health and welfare of the population.

These features become especially important after a hazard event. Critical facilities typically include public safety stations, schools, department operation centers, and emergency operations centers. Critical infrastructure can include the roads and bridges that provide ingress and egress and allow emergency vehicles access to those in need, and the utilities that provide water, electricity, and communication services to the community. Critical facilities identified in this plan were selected, mapped, and included in geographic information system (GIS) databases based on information provided through the Working Group meetings, stakeholder information requests, and the 2018 State of California Multi-Hazard Mitigation Plan.

Although many facilities and assets of the Santa Clara County OA are important to the quality of life, this plan focuses on those whose loss would result in the greatest impacts on life and safety in the event of a natural hazard. As defined for this hazard mitigation plan update, critical facilities are:

Structures or other improvements, public or private, that, because of function, size, service area, or uniqueness, have the potential to cause serious bodily harm, extensive property damage, or disruption of vital socioeconomic activities if it is destroyed or damaged or if its functionality is impaired. Critical facilities may include but are not limited to health and

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 39 safety facilities, utilities, government facilities, hazardous materials facilities, or vital community economic facilities.1F
12 All critical facilities and infrastructure were analyzed in Hazus to help rank risk and identify mitigation actions. The risk assessment for each hazard qualitatively discusses critical facilities with regard to that hazard. Table 11 summarizes the general types of critical facilities and infrastructure by local jurisdiction.

Figure 10 and Figure 11 show the locations of critical facilities and infrastructure in the OA. Due to the sensitivity of this information, a detailed list of facilities is not provided. The list is on file with Santa Clara County OEM.

Table 11: Critical Facilities and Infrastructure in the Operational Area Jurisdiction Essential
Facilities Transportation Utilities Hazardous Materials Community
Assets Jurisdiction
Campbell 21 23 0 6 7 93
Cupertino 26 26 2 5 16 95
Gilroy 25 34 2 7 13 118
Los Altos 22 8 0 0 11 73
Los Altos Hills 6 21 0 0 2 55
Los Gatos 20 35 0 1 6 79
Milpitas 32 66 1 60 19 178
Monte Sereno 1 1 0 0 1 5
Morgan Hill 22 14 1 8 10 69
Mountain View 37 52 1 20 29 174
Palo Alto 49 42 4 26 46 207
San José 370 498 18 135 191 1,479
Santa Clara
(city)
53 63 9 103 36 295
Saratoga 18 32 0 0 11 70
Sunnyvale 40 49 3 51 27 232
Unincorporated
County
38 187 17 4 48 327
Total 777 1151 58 426 473 3,549
12 Organization of American States. (n.d.). Critical Facilities Mapping. https://www.oas.org/dsd/publications/Unit/oea66e/ch07.htm

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 40 Figure 11: Critical Facilities in the Operational Area

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 41 Figure 12: Critical Infrastructure in the Operational Area

5.5.3 Future Trends in Development
An understanding of population and development trends can assist in planning for future development and ensuring that appropriate mitigation, planning, and preparedness measures are in place to protect human health and community infrastructure. The DMA requires that communities consider land use trends, which can alter the need for, and priority of, mitigation options over time. Land use and development trends significantly affect exposure and vulnerability to various hazards. For example, significant development in a hazard area increases the building stock and population exposed to that hazard. New development that has occurred in the last five years within the OA and potential future development in the next five years, as identified by each jurisdiction, is addressed in the planning partner annexes located in Volume 2 of this plan.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 42 The municipal planning partners have adopted general plans that govern land use decision and policy making for their jurisdictions. Decisions on land use will be governed by these programs. This plan will work together with these programs to support wise land use in the future by providing vital information on the risk associated with natural hazards in the OA. Incorporating information from the hazard mitigation into the general plan as the plans are updated will ensure that future development will be established with the benefits of the information on risk and vulnerability to natural hazards identified in this plan.

5.6 Demographics
Some populations are at greater risk from hazard events because of decreased resources or physical abilities. Those who are older, for example, may be more likely to require additional assistance. Research has shown that people living near or below the poverty line, those who are older, women, children, those who are racial and/or ethnic minorities, renters, individuals with disabilities, and others with access and functional needs, may all experience more severe impacts from disasters than the general population.

These more vulnerable populations may vary from the general population in risk perception, living conditions, access to information before, during, and after a hazard event, capabilities during an event, and access to resources for post-disaster recovery. Indicators of vulnerability—such as disability, age, poverty, and minority race and ethnicity—often overlap spatially and often in the geographically most vulnerable locations. Detailed spatial analysis to locate areas where there are higher concentrations of more vulnerable community members helps to extend focused public outreach and education and resources to these most vulnerable residents.

5.6.1 Population
Resident Population
Information about population is a critical part of planning because it directly relates to land needs such as housing, industry, stores, public facilities and services, and transportation. The 2020 U.S. Census estimated the OA’s population at 1,936,259.12 F
13 Population changes are useful socio-economic indicators. A growing population generally indicates a growing economy, while a decreasing population signifies economic decline. In this case, population estimates are assumed to be influenced by the COVID-19 pandemic, rising cost of living including housing, and decline in foreign immigration due to change in federal policy. Since 2011, California has experienced an increased number of people moving out of the State in a year than into it. The OA is no exception. Table 12 shows the population in the OA from 2000 to 2022 according to the California Finance Department.

Table 12: Recent Population Data13F
14 Jurisdiction
Population
2000 2005 2010 2015 2022
City of Campbell 38,138 37,406 39,349 41,986 42,833
13 United States Census Bureau. (2020). Quick Facts: Santa Clara County. https://www.census.gov/quickfacts/santaclaracountycalifornia 14 State of California Department of Finance. (2021, December). E-2 California County Population Estimates and Components of Change by Year. https://dof.ca.gov/Forecasting/Demographics/e-2-california-county-populationestimates-and-components-of-change-byyear/#:~:text=California%E2%80%99s%20population%20declined%20by%20173%2C000%20persons%20between %20July,estimates%20released%20today%20by%20the%20Department%20of%20Finance.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 43 Jurisdiction
Population
2000 2005 2010 2015 2022
City of Cupertino 50,546 53,632 58,302 58,038 59,610
City of Gilroy 41,464 45,782 48,821 54,324 59,269
City of Los Altos 27,693 27,381 28,976 30,513 31,526
Town of Los Altos Hills 7,902 7,852 7,922 8,595 8,400
Town of Los Gatos 28,592 28,070 29,413 31,157 33,062
City of Milpitas 62,698 62,177 66,790 74,140 80,839
City of Monte Sereno 3,483 3,324 3,341 3,445 3,488
City of Morgan Hill 33,556 35,011 37,822 42,382 46,451
City of Mountain View 70,708 70,629 74,066 76,712 83,864 City of Palo Alto 58,598 60,723 64,403 67,331 67,473
City of San José 894,943 901,159 945,942 1,030,053 976,482 City of Santa Clara 102,361 107,058 116,468 121,580 130,127 City of Saratoga 29,843 29,630 29,926 30,060 30,667
City of Sunnyvale 131,760 131,853 140,081 146,629 156,234 Unincorporated County 100,300 96,547 90,020 87,029 84,458 Total 1,682,585 1,698,234 1,781,642 1,903,974 1,894,783 Daily Commuting Population
According to the California Employment Development Department, Santa Clara County is the single largest commuter destination in Submarket C of the San Francisco Bay Area Economic Market, holding and/or importing 1,009,391 commuters daily.14F
15 This large commuter contingent has impacts on planning for the OA’s infrastructure and service needs, as well as on planning for hazard mitigation and emergency management. Commuters may be familiar with the area immediately surrounding their place of business or regular route to work but may be less familiar with the services and resources provided to the population during a disaster event.

The U.S. Census estimates that over 66.8 percent of workers in the OA commute alone (by car, truck, or van) to work, and mean travel time to work is 24 minutes. The state average is 28 minutes.15F 16 5.6.2 Age Distribution
As a group, the adults who are older are more apt to lack the physical and economic resources necessary for response and resiliency for hazard events and are more likely to suffer health-related consequences making recovery slower. They are more likely to be vision, hearing, and/or mobility impaired, and more likely to experience mental impairment or dementia. Additionally, adults who are older are more likely to live in assisted- living facilities where emergency preparedness occurs at the discretion of facility operators. These facilities are typically identified as “critical facilities” by emergency managers because 15 California Employment Development Department. (2020, August 28). WIOA Regional Planning Units. https://edd.ca.gov/siteassets/files/Jobs_and_Training/pubs/wsd20-01.pdf 16 United States Census Bureau. (2020). Quick Facts: Santa Clara County; California. https://www.census.gov/quickfacts/fact/table/santaclaracountycalifornia,CA/LFE305221

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 44 they require extra notice to implement evacuation. Residents who are older and living in their own homes may have more difficulty evacuating and could be stranded in dangerous situations. This population group is more likely to need special medical attention, which may not be readily available during natural disasters due to isolation caused by the event. Specific planning attention for the those who are older is an important consideration given the current trend of aging of the American population.

Children under 18 are particularly vulnerable to disaster events as well because of their young age and dependence on others for basic necessities. Children often experience increased physical and health challenges as well as issues learning after a disaster event. Additionally, very young children may be vulnerable to injury or sickness; this added vulnerability can be worsened during a natural disaster because they may not understand the measures that need to be taken to protect themselves from hazards. The unique needs of children are important to factor into disaster response and recovery efforts as well as when calculating the benefit and costs of mitigation alternatives. 16F 17 The overall age distribution for the OA is illustrated in Figure 13. Based on U.S. Census 2021 American Community Survey 1-Year Estimate, the mean age in the OA is 48.2 compared to California’s mean age of 37.6 years. Additionally, 14.5 percent of the OA’s population is 65 or older, compared to the state estimate of 15.2 percent. An estimated 21.2 percent of the OA population is 18 or younger, compared to the state estimate of 22.4 percent.

Figure 13: Overall Age Distribution in the Operational Area17F 18 17 Society for Research in Child Development. (2020, August 13). Understanding the Impacts of Natural Disasters on Children. https://www.srcd.org/research/understanding-impacts-natural-disasterschildren#:~:text=Every%20year%2C%20175%20million%20children%20globally%20are%20expected,communities% 20better%20prepare%20for%20and%20respond%20to%20disasters. 18 United States Census Bureau. (2021). American Community Survey, Age and Sex Santa Clara County, California. https://data.census.gov/table?q=Age+in+Santa+Clara+County+2021&tid=ACSST1Y2021.S0101

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5.6.3 Race, Ethnicity, and Language
Research shows that racial and ethnic minorities are less likely to be involved in pre-disaster planning and experience higher mortality rates during a disaster event. Post-disaster recovery can be ineffective and is often characterized by cultural insensitivity. Since higher proportions of ethnic minorities live below the poverty line than the majority white population, poverty can compound vulnerability. According to the 2020 U.S. Census, the racial composition of the OA is predominantly Asian, at about 39 percent. The next most common race is White, at 32 percent. The racial distribution in the OA is shown below.

The OA has a 40.3 percent foreign-born population. Other than English, the most commonly spoken languages in the OA are Chinese, Vietnamese, and Tagalog, followed by Spanish.18F 19 Figure 14: Race Distribution in the Operational Area19F 20 5.6.4 Education
Understanding educational attainment of the population is important when developing appropriate outreach and educational materials. The U.S. Census estimates that 28 percent of the population OA 25 years and older has attained a bachelor’s degree, and 27 percent a graduate or professional degree.

Seventy-six percent of the population has attended college for some period, and 10 percent have not achieved a high school or equivalent degree.20 F
21 19 United States Census Bureau. (2020). Santa Clara County, California. https://data.census.gov/profile?g=050XX00US06085
20 United States Census Bureau. (2020). Santa Clara County, California. https://data.census.gov/profile?g=050XX00US06085
21 United States Census Bureau. (2020). Santa Clara County, California. https://data.census.gov/profile?g=050XX00US06085

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5.6.5 Individuals with Disabilities or with Access or Functional Needs The U.S. Census estimates that over 42 million non-institutionalized people with disabilities live in the U.S. Individuals with disabilities are more likely to have difficulty with resilience and responding to a hazard event than the general population.21F
22 Local government may be the first level of response to assist these individuals, and coordination of efforts to meet their access and functional needs is paramount to life safety efforts. It is important for emergency and incident managers to distinguish between functional and medical needs in order to plan for incidents that require evacuation and sheltering. Knowing the percentage of population with a disability will allow emergency management personnel and first responders to have personnel available who can provide services needed by those with access and functional needs.

According to the U.S. Census 2021 American Community Survey 1-Year Estimates, 169,467, or 9 percent, of individuals have some form of disability in the OA.2 F 23 5.6.6. Social Vulnerability
The Social Vulnerability Index provides a visual representation of the potential negative effects on communities that natural hazards or other external stresses on human health. The index is based on 16 variables from the U.S. Census to indicate areas that may need additional support before, during or after disasters. These indices include measures of socioeconomic status, household characteristics, racial and ethnic minority status, and housing type and transportation. The overall social vulnerability for Santa Clara County is shown in Figure 14. A summary of the four categories of indices that contribute to the overall index is shown in Figure 15. The darker toned colors indicate areas with potentially higher vulnerability.
22 United States Census Bureau. (2020). United States. https://data.census.gov/profile/United_States?g=010XX00US 23 United States Census Bureau. (2020). Santa Clara County, California. https://data.census.gov/profile?g=050XX00US06085

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 47 Figure 15: Santa Clara County Social Vulnerability Index

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 48 Figure 16: Social Vulnerability Index Themes

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5.7 Economy

5.7.1 Income
In the United States, individual households are expected to use private resources to prepare for, respond to and recover from disasters to some extent. This means economically disadvantaged households are automatically disadvantaged when confronting hazards. Additionally, those who are economically disadvantaged typically occupy more poorly built and inadequately maintained housing. Mobile or modular homes, for example, are more susceptible to damage in earthquakes and floods than other types of housing. In urban areas, those who are economically disadvantaged often live in older houses and apartment complexes, which are more likely to be made of un-reinforced masonry, a building type that is particularly susceptible to damage during earthquakes. Furthermore, those who are economically disadvantaged are less likely to have insurance to compensate for losses incurred from natural disasters.

This means they may have a great deal to lose during an event and may be the least prepared to deal with potential losses. The events following Hurricane Katrina in 2005 illustrated that personal household economics significantly impact people’s decisions on evacuation. Individuals who cannot afford gas for their cars will likely decide not to evacuate.

A living wage calculator developed at the Massachusetts Institute of Technology estimates the hourly living wage needed to support different types of families. The calculator takes into consideration basic needs such as health, housing, transportation, and other necessities and interprets the living wage as a geographically specific hourly rate required to acquire basic minimum necessities cost. Table 13 presents summary information from the living wage calculator for 2022. Each hourly rate is adjusted per each working adult.

Table 13: Hourly Living Wage Calculation for Santa Clara County, California (2022)23F 24 Wage Level One Adult One Adult + Two
Children Two Adults Two Adults + One Child
Living Wage $26.86 $68.69 $38.42 $46.79
Poverty Wage $6.53 $11.07 $8.80 $11.07
Minimum Wage $15.50 $15.50 $15.50 $15.50
Based on 2022 U.S. Census Bureau estimates, the median household income in Santa Clara County was $141,562. It is estimated that about 16 percent of households receive an income between $100,000 and $149,999 per year and over 47 percent of household incomes are above $150,000 annually. About 9 percent of the households in the OA make less than $25,000 per year. The poverty threshold for a family of four in 2022 was $30,186; for a family of three, $22,892; for a family of two under 65 years, $19,597 and for unrelated individuals under 65 years, $15,225.24 F 25 The 2015 living wage calculations cited in the 2017 Hazard Mitigation Plan were notably different than the current estimates. For example, the living wage for one adult was $14.52 and $11.30 for two adults.

When incomes do not match the cost-of-living increase, households may be forced to reduce household on nonessential items. Hazard mitigation measures, such as flood insurance and voluntary structural retrofitting, are not usually considered essential despite their demonstrated long-term cost effectiveness. 24 Massachusetts Institute of Technology. (2023). Living Wage Calculator, Santa Clara County. https://livingwage.mit.edu/counties/06085
25 United States Census Bureau. (2020). Santa Clara County, California. https://data.census.gov/profile?g=050XX00US06085

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5.8 Industry, Businesses, and Institutions
The county’s economy is strongly based in the professional, scientific, and management, and administrative and waste management services industry, followed by educational services and health care and social assistance, manufacturing, and retail trade. Figure 16 shows the breakdown of industry types in the OA. Santa Clara County is part of one of the state’s busiest urbans areas.

The OA benefits from a variety of business activity. Major businesses include Apple, Inc, Alphabet Inc. (Google), Netflix, Roku, Inc. Shockley Semiconductor Laboratory, eBay Inc., Cisco Systems Inc., Applied Materials Inc., Flextronics International, Intel Corp, Kaiser Permanente Medical Center, Liberty Tax Service, Lockheed Martin Space Systems, NASA, Phillips Lumileds Lighting Company, Santa Clara Valley Medical Center, and many others.

Major educational and research institutions in the OA include Stanford University, San José State University, Santa Clara University, Mission College, De Anza College, Foothill College, West Valley College, Mission College, Evergreen Valley College, San José City College, and Gavilan College.

Figure 17: Industry in Santa Clara County

5.8.1 Employment Trends and Occupations
According to the Census Bureau, 66.6 percent of the Santa Clara County population 16 years and over is in the labor force. Management, business, science, and arts occupations make up 59 percent of jobs in the County. Other major occupations include sales and office (15 percent) and service (13 percent).

Multiple major employers in California are located in Santa Clara County, including Apple, Cisco Systems, Advanced Micro Devices Inc, Amazon, Apple, Applied Materials Inc, California’s Great America, Cisco

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 51 Systems, Intel Corp, Intuit, Hewlett Packard Enterprise, Alphabet Inc. (Google), and Nvidia Corp., and Yahoo. The largest of these are Applied Materials Inc, Apple, Cisco Systems, Intel Inc, Hewlett Packard Enterprise, Google, and Yahoo each with 10,000 or more employees. The others employ between 1,000- 4,999 employees.25F
26 Figure 18: Occupations in Santa Clara County
The figure below compares the California and the Santa Clara County unemployment trends from 2017 to 2021. According to the State of California’s Employment Development Department, the Santa Clara County unemployment rate was trending downward prior to 2020 when it spiked upward, likely in part due to the COVID-19 pandemic. By 2021, the unemployment rates started to fall again. They continued to fall below pre-pandemic estimates in 2022. Overall, Santa Clara County experienced less unemployment than the rest of the State throughout this time period.26 F 27 26 United States Census Bureau. (2021). American Community Survey, Selected Economic Characteristics Santa Clara County, California.
https://data.census.gov/table?q=employment+in+Santa+Clara+County,+California&tid=ACSDP1Y2021.DP03 27 State of California Employment Development Department. (2023). Economic Development Data Library. https://data.edd.ca.gov/

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 52 Figure 19: California and Santa Clara County Unemployment Rate27F 28 5.9 Laws and Ordinances
Existing laws, ordinances, and plans at the federal, state, and local level can support or impact hazard mitigation actions identified in this plan. Hazard mitigation plans are required to include a review and incorporation, if appropriate, of existing plans, studies, reports, and technical information as part of the planning process (44 CFR, Section 201.6(b)(3)). The following federal and state programs have been identified as programs that may interface with the actions identified in this plan. Each program enhances capabilities to implement mitigation actions or has a nexus with a mitigation action in this plan.

Information presented in this section can be used in addition to local capabilities to implement the actions found in the jurisdictional and special district annexes of Volume 2 of this plan. Each planning partner has individually reviewed existing local plans, studies, reports, and technical information in its jurisdictional or special district annexes, presented in Volume 2 of this plan.

5.9.1 Federal
Stafford Act
The Stafford Disaster Relief and Emergency Assistance Act (“Stafford Act”) is the statutory authority for most Federal disaster response activities for FEMA and FEMA programs. The Stafford Act initially provided limited resources mitigation and pre-disaster community resilience. It did include the PresDisaster Hazard Mitigation (PDM) program however, funding was often ad hoc and historically much less than traditional disaster spending. Subsequent legislation has since amended the Stafford Act, opening the doors to additional mitigation opportunity.
28 State of California Employment Development Department. (2023). Economic Development Data Library. https://data.edd.ca.gov/

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 53 Disaster Mitigation Act
The DMA is the current federal legislation addressing hazard mitigation planning. It emphasizes planning for disasters before they occur. It specifically addresses planning at the local level, requiring plans to be in place before certain hazard mitigation funds are available to communities. This plan is designed to meet the requirements of DMA, improving eligibility for future hazard mitigation funds.

Disaster Recovery Reform Act
The Disaster Recovery Reform Act of 2018 amended the Stafford Act and provided 56 provisions for FEMA policy or regulation changes. Crucially, the Act set aside 6 percent of the total aid amount awarded in the previous year for pre-disaster mitigation. FEMA estimates this mean $300-500 million dollars will be available for mitigation annually.28F
29 This creates a much more consistent, reliable stream of pre-disaster mitigation dollars than ever seen before. Additionally, the Act expanded language for the Hazard Mitigation Grant Program (HMGP) to include an increased focused on resilience and reducing future damage in the post-disaster environment which may encourage proactive mitigation measures. It also provided states, tribes, and local jurisdictions with additional authority to use FEMA funding to rebuild to the latest building codes to reduce future risk to the Nation.

National Environmental Policy Act
The National Environmental Policy Act (NEPA) requires federal agencies to consider the environmental impacts of proposal actions and reasonable alternatives to those actions, alongside technical and economic considerations. NEPA established the Council on Environmental Quality (CEQ), whose regulations (40 CFR Parts 1500-1508) set standards for NEPA compliance. Consideration and decisionmaking regarding environmental impacts must be documented in an environmental impact statement or environmental assessment. Environmental impact assessment requires the evaluation of reasonable alternatives to a proposed action, solicitation of input from organizations and individuals that could be affected, and an unbiased presentation of direct, indirect, and cumulative environmental impacts. FEMA hazard mitigation project grant applications require full compliance with applicable federal acts. Any action identified in this plan that falls within the scope of this act will need to meet its requirements.

Endangered Species Act
The federal Endangered Species Act (ESA) was enacted in 1973 to conserve species facing depletion or extinction and the ecosystems that support them. The act sets forth a process for determining which species are threatened and endangered and requires the conservation of the critical habitat in which those species live. The ESA provides broad protection for species of fish, wildlife and plants that are listed as threatened or endangered. Provisions are made for listing species, as well as for recovery plans and the designation of critical habitat for listed species. The ESA outlines procedures for federal agencies to follow when taking actions that may jeopardize listed species and contains exceptions and exemptions.

It is the enabling legislation for the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Criminal and civil penalties are provided for violations of the ESA and the Convention. 29 Federal Emergency Management Agency (FEMA). (2020). Hazard Mitigation Assistance. https://sgp.fas.org/crs/homesec/IN11187.pdf

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 54 Federal agencies must seek to conserve endangered and threatened species and use their authorities in furtherance of the ESA’s purposes. The ESA defines three fundamental terms:29F 30  Endangered means that a species of fish, animal or plant is “in danger of extinction throughout all or a significant portion of its range.” (For salmon and other vertebrate species, this may include subspecies and distinct population segments.)
 Threatened means that a species “is likely to become endangered within the foreseeable future.” Regulations may be less restrictive for threatened species than for endangered species.  Critical habitat means “specific geographical areas that are…essential for the conservation and management of a listed species, whether occupied by the species or not.” Five sections of the ESA are of critical importance to understanding it:
 Section 4: Listing of a Species—The National Oceanic and Atmospheric Administration (NOAA) Fisheries Service is responsible for listing marine species; the U.S. Fish and Wildlife Service is responsible for listing terrestrial and freshwater aquatic species. The agencies may initiate reviews for listings, or citizens may petition for them. A listing must be made “solely on the basis of the best scientific and commercial data available.” After a listing has been proposed, agencies receive comment and conduct further scientific reviews for 12 to 18 months, after which they must decide if the listing is warranted. Economic impacts cannot be considered in this decision, but it may include an evaluation of the adequacy of local and state protections. Critical habitat for the species may be designated at the time of listing.
 Section 7: Consultation—Federal agencies must ensure that any action they authorize, fund, or carry out is not likely to jeopardize the continued existence of a listed or proposed species or adversely modify its critical habitat. This includes private and public actions that require a federal permit. Once a final listing is made, non-federal actions are subject to the same review, termed a “consultation.” If the listing agency finds that an action will “take” a species, it must propose mitigations or “reasonable and prudent” alternatives to the action; if the proponent rejects these, the action cannot proceed.
 Section 9: Prohibition of Take—It is unlawful to “take” an endangered species, including killing or injuring it or modifying its habitat in a way that interferes with essential behavioral patterns, including breeding, feeding, or sheltering.
 Section 10: Permitted Take—Through voluntary agreements with the federal government that provide protections to an endangered species, a non-federal applicant may commit a take that would otherwise be prohibited as long as it is incidental to an otherwise lawful activity (such as developing land or building a road). These agreements often take the form of a “Habitat Conservation Plan.”
 Section 11: Citizen Lawsuits—Civil actions initiated by any citizen can require the listing agency to enforce the ESA’s prohibition of taking or to meet the requirements of the consultation process.

FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Any action identified in this plan that falls within the scope of this act will need to meet its requirements. 30 National Oceanic and Atmospheric Administration. (n.d.). Glossary: Endangered Species Act. https://www.fisheries.noaa.gov/laws-and-policies/glossary-endangered-speciesact#:~:text=A%20threatened%20species%20is%20defined%20under%20the%20ESA,threatened%20or%20endange red%20are%20called%20%E2%80%9C%20listed%20species.%E2%80%9D

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 55 The Clean Water Act
The federal Clean Water Act (CWA) employs regulatory and non-regulatory tools to reduce direct pollutant discharges into waterways, finance municipal wastewater treatment facilities, and manage polluted runoff. These tools are employed to achieve the broader goal of restoring and maintaining the chemical, physical, and biological integrity of the nation’s surface waters so that they can support “the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water.” Evolution of CWA programs over the last decade has included a shift from a program-by-program, source-by-source, and pollutant-by-pollutant approach to more holistic watershed-based strategies.

Under the watershed approach, equal emphasis is placed on protecting healthy waters and restoring impaired ones. A full array of issues is addressed, not just those subject to CWA regulatory authority.

Involvement of stakeholder groups in the development and implementation of strategies for achieving and maintaining water quality and other environmental goals is a hallmark of this approach.

FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Any action identified in this plan that falls within the scope of this act will need to meet its requirements.

National Flood Insurance Program
The National Flood Insurance Program (NFIP) provides federally backed flood insurance in exchange for communities enacting floodplain regulations. Participation and good standing under NFIP are prerequisites to grant funding eligibility under the Robert T. Stafford Act. Santa Clara County and all of the partner cities for this plan participate in the NFIP and have adopted regulations that meet the NFIP requirements. At the time of the preparation of this plan, all participating jurisdictions in the partnership were in good standing and in full compliance with the minimum requirements of the NFIP.

Community Rating System
The Community Rating System (CRS) is a voluntary incentive program for communities that participate in the NFIP and adopt and enforce floodplain management practices that exceed minimum requirements.

Flood insurance premium discounts reflect the ways in which the community meets the following goals of the program:
 Reduce and avoid flood damage to insurable property.
 Strengthen and support the insurance aspects of the National Flood Insurance Program.  Foster comprehensive floodplain management.

Participating in the CRS program not only encourages communities to reduce the risk to life and property from flooding through a proactive floodplain management program, but provides a clear, monetary incentive for residents for supporting mitigation activities. Many planning partners participate in the CRS.

Many planning partners participate in the CRS. The planning partners discussed using this plan to meet CRS requirements as well. Ultimately, it was decided that Santa Clara Valley Water will lead the development of a separate Floodplain Management Plan specifically dedicated towards this goal, allowing planning partners that participate in the CRS program to maintain or enhance their CRS classifications. Relevant information from this Hazard Mitigation Plan will be incorporated into the Floodplain Management Plan.

Coastal Zone Management Act
The national Coastal Zone Management Act requires federal agencies to conduct their planning, management, development, and regulatory activities in a manner consistent to the maximum extent practicable with the policies of state Coastal Zone Management (CZM) programs. State CZM lead agencies have the authority to review federal actions for consistency with their federally approved CZM programs.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 56 In California, the California Coastal Commission, the Bay Conservation and Development Commission, and the California Coastal Conservancy are the three CZM agencies empowered to conduct federal consistency reviews. The informational and procedural requirements for CZM federal consistency reviews are prescribed by federal regulations (15 CFR 930). Any action identified in this plan that falls within the scope of this act will need to meet its requirements.

National Incident Management System
The National Incident Management System is a systematic approach for government, nongovernmental organizations, and the private sector to work together to manage incidents involving hazards. The system provides a flexible but standardized set of incident management practices. Incidents typically begin and end locally, and they are managed at the lowest possible geographical, organizational, and jurisdictional level. In other instances, success depends on the involvement of multiple jurisdictions, levels of government, functional agencies, and emergency-responder disciplines. These instances necessitate coordination across this spectrum of organizations. Communities using the National Incident Management System follow a comprehensive national approach that improves the effectiveness of emergency management and response personnel across the full spectrum of potential hazards (including natural hazards, terrorist activities, and other human-caused disasters) regardless of size or complexity.

Although participation is voluntary, federal departments and agencies are required to make adoption of NIMS by local and state jurisdictions a condition to receive federal preparedness grants and awards. The content of this plan is considered to be a viable support tool for any phase of emergency management.

The NIMS program is considered as a response function, and information in this hazard mitigation plan can support the implementation and update of all NIMS-compliant plans within the planning area.

Americans with Disabilities Act and Amendments
The Americans with Disabilities Act (ADA) seeks to prevent discrimination against people with disabilities in employment, transportation, public accommodation, communications, and government activities. The most recent amendments became effective in January 2009 (P.L. 110-325). Title II of the ADA deals with compliance with the act in emergency management and disaster-related programs, services, and activities. It applies to state and local governments as well as third parties, including religious entities and private nonprofit organizations.

The ADA has implications for sheltering requirements and public notifications. During an emergency alert, officials must use a combination of warning methods to ensure that all residents have any necessary information. Those with hearing impairments may not hear radio, television, sirens, or other audible alerts, while those with visual impairments may not see flashing lights or visual alerts. Two stand-alone technical documents have been issued for shelter operators to meet the needs of people with disabilities. These documents address physical accessibility as well as medical needs and service animals.

The ADA also intersects with disaster preparedness programs in regard to transportation, social services, temporary housing, and rebuilding. Persons with disabilities may require additional assistance in evacuation and transit (such as vehicles with wheelchair lifts or paratransit buses). Evacuation and other response plans should address the unique needs of residents. Local governments may be interested in implementing a special-needs registry to identify the home addresses, contact information, and needs for residents who may require more assistance.

FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Any action identified in this plan that falls within the scope of this act will need to meet its requirements.

Civil Rights Act of 1964
The Civil Rights Act of 1964 prohibits discrimination based on race, color, religion, sex, or national origin and requires equal access to public places and employment. The act is relevant to emergency management and hazard mitigation in that it prohibits local governments from favoring the needs of one population group over another.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 57 Local government and emergency response must ensure the continued safety and well-being of all residents equally, to the extent possible. FEMA hazard mitigation project grant applications require full compliance with applicable federal acts. Any action identified in this plan that falls within the scope of this act will need to meet its requirements.

Rural Development Program
The mission of the U.S. Department of Agriculture (USDA) Rural Development Program is to help improve the economy and quality of life in rural America. The program provides project financing and technical assistance to help rural communities provide the infrastructure needed by rural businesses, community facilities, and households. The program addresses rural America’s need for basic services, such as clean running water, sewage and waste disposal, electricity, and modern telecommunications and broadband. Loans and competitive grants are offered for various community and economic development projects and programs, such as the development of essential community facilities including fire stations. Some of the actions identified in this plan may be eligible for funding available under this program.

Community Development Block Grant Disaster Resilience Program In response to disasters, Congress may appropriate additional funding for the U.S. Department of Housing and Urban Development Community Development Block Grant programs to be distributed as Disaster Recovery grants (CDBG-DR). These grants can be used to rebuild affected areas and provide seed money to start the recovery process. CDBG-DR assistance may fund a broad range of recovery activities, helping communities and neighborhoods that otherwise might not recover due to limited resources. CDBG-DR grants often supplement disaster programs of FEMA, the Small Business Administration, and the U.S. Army Corps of Engineers. Housing and Urban Development generally awards noncompetitive, nonrecurring CDBG-DR grants by a formula that considers disaster recovery needs unmet by other federal disaster assistance programs. To be eligible for CDBG-DR funds, projects must meet the following criteria:
 Address a disaster-related impact (direct or indirect) in a presidentially declared county for the covered disaster.
 Be a CDBG-eligible activity (according to regulations and waivers).  Meet a national objective.

Incorporating preparedness and mitigation into these actions is encouraged, as the goal is to rebuild in ways that are safer and stronger. CDGB-DR funding is a potential alternative source of funding for actions identified in this plan.

Community Development Block Grant Mitigation
The Community Development Block Grant Mitigation (CDBG-MIT) program was developed to support communities impacted by recent disasters in carrying out strategic and high-impact mitigation actions to reduce losses from future events. Congress may appropriate additional CDBG-MIT funding for the U.S.

Department of Housing and Urban Development following a disaster event. The goals of CDBG-MIT funding are:
 Support data-informed investments, focusing on repetitive loss of property and critical infrastructure;
 Build capacity to comprehensively analyze disaster risks and update hazard mitigation plans;  Support the adoption of policies that reflect local and regional priorities that will have long-lasting effects on community risk reduction, including risk reduction to community lifelines and decreasing future disaster costs; and

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 58  Maximize the impact of funds of encouraging leverage, private/public partnerships, and coordination with other federal dollars.

This would be a potential post-disaster financial capability of jurisdictions covered in this plan which could be put towards implementing the identified mitigation actions.

Emergency Watershed Program
The USDA Natural Resources Conservation Service administers the Emergency Watershed Protection Program, which responds to emergencies created by natural disasters. Eligibility for assistance is not dependent on a national emergency declaration. The program is designed to help people and conserve natural resources by relieving imminent hazards to life and property caused by floods, fires, windstorms, and other natural occurrences. The Emergency Watershed Protection is an emergency recovery program.

Financial and technical assistance are available for the following activities:30 F 31  Remove debris from stream channels, road culverts, and bridges.  Reshape and protect eroded banks.
 Correct damaged drainage facilities.
 Establish cover on critically eroding lands.
 Repair levees and structures.
 Repair conservation practices.

This federal program could be a possible funding source for actions identified in this plan.

Presidential Executive Orders 11988 and 13690
Executive Order 11988 requires federal agencies to avoid to the extent possible the long and short-term adverse impacts associated with the occupancy and modification of floodplains and to avoid direct and indirect support of floodplain development wherever there is a practicable alternative. It requires federal agencies to provide leadership and take action to reduce the risk of flood loss, minimize the impact of floods on human safety, health, and welfare, and restore and preserve the natural and beneficial values of floodplains. The requirements apply to the following activities31F 32:
 Acquiring, managing, and disposing of federal lands and facilities.  Providing federally undertaken, financed, or assisted construction and improvements.  Conducting federal activities and programs affecting land use, including but not limited to water and related land resources planning, regulation, and licensing.

Executive Order 13690 expands Executive Order 11988 and acknowledges that the impacts of flooding are anticipated to increase over time due to the effects of climate change and other threats. It mandates a federal flood risk management standard to increase resilience against flooding and help preserve the natural values of floodplains. This standard expands management of flood issues from the current base flood level to a higher vertical elevation and corresponding horizontal floodplain when federal dollars are involved in a project.
31 National Resources Conservation Service. (n.d.). Emergency Watershed Protection. https://www.nrcs.usda.gov/programs-initiatives/ewp-emergency-watershed-protection/kentucky/emergencywatershed-protection 32 Federal Emergency Management Agency. (2015, October 8). Guidelines for Implementing Executive Order 11988. https://www.fema.gov/sites/default/files/documents/fema_implementing-guidelines-EO11988-13690_10082015.pdf

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 59 The goal is to address current and future flood risk and ensure that projects funded with taxpayer dollars last as long as intended.32F
33 All actions identified in this plan will seek full compliance with all applicable presidential executive orders.

Presidential Executive Order 11990
Executive Order 11990 requires federal agencies to provide leadership and take action to minimize the destruction, loss, or degradation of wetlands, and to preserve and enhance the natural and beneficial values of wetlands. The requirements apply to the following activities:3 F 34  Acquiring, managing, and disposing of federal lands and facilities.  Providing federally undertaken, financed, or assisted construction and improvements.  Conducting federal activities and programs affecting land use, including but not limited to water and related land resources planning, regulation, and licensing.

All actions identified in this plan will seek full compliance with all applicable presidential executive orders.

Emergency Relief for Federally Owned Roads Program
The U.S. Forest Service’s Emergency Relief for Federally Owned Roads Program was established to assist federal agencies with repair or reconstruction of tribal transportation facilities, federal lands transportation facilities, and other federally owned roads that are open to public travel and have suffered serious damage by a natural disaster over a wide area or by a catastrophic failure. The program funds both emergency and permanent repairs.34F
35 Eligible activities under this program meet some of the goals and objectives for this plan and the program is a possible funding source for actions identified in this plan.

U.S. Army Corps of Engineers Programs
The U.S. Army Corps of Engineers has several civil works authorities and programs related to flood risk and flood hazard management:
 Floodplain Management Services are 100-percent federally funded technical services such as development and interpretation of site-specific data related to the extent, duration, and frequency of flooding. Special studies may be conducted to help a community understand and respond to flood risk. These may include flood hazard evaluation, flood warning and preparedness, or flood modeling.
 For more extensive studies, the Corps of Engineers offers a cost-shared program called Planning Assistance to States and Tribes. Studies under this program generally range from $25,000 to $100,000, with the local jurisdiction providing 50 percent of the cost.  The Corps of Engineers has several cost-shared programs (typically 65 percent federal and 35 percent non-federal) aimed at developing, evaluating, and implementing structural and nonstructural capital projects to address flood risks at specific locations or within a specific watershed:
33 Obama White House. (2015, January 30). Executive Order – Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input. https://obamawhitehouse.archives.gov/the-press-office/2015/01/30/executive-order-establishing-federal-flood-riskmanagement-standard-and34 National Archives. (n.d.). § 9.4 Definitions. https://www.ecfr.gov/current/title-44/chapter-I/subchapter-A/part9/section-9.4 35 Federal Highway Administration. (n.d.). Fact Sheets, Emergency Relief Program. https://www.fhwa.dot.gov/bipartisan-infrastructurelaw/er_fact_sheet.cfm#:~:text=The%20BIL%20continues%20the%20Emergency%20Relief%20program%2C%20whi ch,disasters%20or%20catastrophic%20failure%20from%20an%20external%20cause.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 60 ▪ The Continuing Authorities Program for smaller-scale projects includes Section 205 for Flood Control, with a $7 million federal limit and Section 14 for Emergency Streambank Protection with a $1.5 million federal limit. These can be implemented without specific authorization from Congress.
▪ Larger scale studies, referred to as General Investigations, and projects for flood risk management, for ecosystem restoration or to address other water resource issues, can be pursued through a specific authorization from Congress and are cost-shared, typically at 65 percent federal and 35 percent non-federal.
▪ Watershed Management planning studies can be specifically authorized and are cost-shared at 50 percent federal and 50 percent non-federal.
 The Corps of Engineers provides emergency response assistance during and following natural disasters. Public Law 84-99 enables the Corps to assist state and local authorities in flood fight activities and cost share in the repair of flood protective structures. Assistance afforded under PL 84-99 is broken down into the following categories:
▪ Preparedness: The Flood Control and Coastal Emergency Act establishes an emergency fund for preparedness for emergency response to natural disasters; for flood fighting and rescue operations; for rehabilitation of flood control and hurricane protection structures.

Funding for Corps of Engineers emergency response under this authority is provided by Congress through the annual Energy and Water Development Appropriation Act. Disaster preparedness activities include coordination, planning, training and conduct of response exercises with local, state, and federal agencies.
▪ Response Activities: PL 84-99 allows the Corps of Engineers to supplement state and local entities in flood-fighting for urban and other non-agricultural areas under certain conditions (Engineering Regulation 500-1-1 provides specific details). All flood-fight efforts require a Project Cooperation Agreement (PCA) signed by the public sponsor and a requirement for the sponsor to remove all flood-fight material after the flood has receded. PL 84-99 also authorizes emergency water support and drought assistance in certain situations and allows for “advance measures” assistance to prevent or reduce flood damage conditions of imminent threat of unusual flooding.
▪ Rehabilitation: Under PL 84-99, an eligible flood protection system can be rehabilitated if damaged by a flood event. The flood system would be restored to its pre-disaster status at no cost to the federal system owner, and at 20-percent cost to the eligible non-federal system owner. All systems eligible for PL 84-99 rehabilitation assistance have to be in the Rehabilitation and Inspection Program prior to the flood event. Acceptable operation and maintenance by the public levee sponsor are verified by levee inspections conducted by the Corps on a regular basis. The Corps has the responsibility to coordinate levee repair issues with interested federal, state, and local agencies following natural disaster events where flood control works are damaged.

All of these authorities and programs are available to the planning partners to support any intersecting mitigation actions.

5.9.2 State
Alquist-Priolo Earthquake Fault Zoning Act
The Alquist-Priolo Earthquake Fault Zoning Act was enacted in 1972 to mitigate the hazard of surface faulting to structures for human occupancy. The Alquist-Priolo Earthquake Fault Zoning Act’s main purpose is to prevent construction of buildings used for human occupancy on the surface trace of active faults. Before a new project is permitted, cities and counties require a geologic investigation to demonstrate that proposed buildings will not be constructed on active faults.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 61 The act addresses only the hazard of surface fault rupture and is not directed toward other earthquake hazards, such as liquefaction or seismically induced landslides. The law requires geologists from the State of California to establish regulatory zones around the surface traces of active faults and to issue appropriate maps. The maps are distributed to all affected cities, counties, and state agencies for their use in planning and controlling new or renewed construction. Local agencies must regulate most development projects within the zones. Projects include all land divisions and most structures for human occupancy. All seismic hazard mitigation actions identified in this plan will seek full compliance with the Alquist-Priolo Earthquake Fault Zoning Act.

California General Planning Law
California state law requires that every county and city prepare and adopt a comprehensive long-range plan to serve as a guide for community development. The general plan expresses the community’s goals, visions, and policies relative to future land uses, both public and private. The general plan is mandated and prescribed by state law (Cal. Gov. Code §65300 et seq.) and forms the basis for most local government land use decision-making.

The plan must consist of an integrated and internally consistent set of goals, policies, and implementation measures. In addition, the plan must focus on issues of the greatest concern to the community and be written in a clear and concise manner. City and county actions, such as those relating to land use allocations, annexations, zoning, subdivision and design review, redevelopment, and capital improvements, must be consistent with the plan.

All municipal planning partners to this plan have general plans that are currently compliant with this law and have committed to integrating this mitigation plan with their general plans through provisions referenced below (AB-2140 and SB-379).

California Environmental Quality Act
The California Environmental Quality Act (CEQA) was passed in 1970, shortly after the federal government enacted the National Environmental Policy Act, to institute a statewide policy of environmental protection. CEQA requires state and local agencies in California to follow a protocol of analysis and public disclosure of the potential environmental impacts of development projects. CEQA makes environmental protection a mandatory part of every California state and local agency’s decisionmaking process.

CEQA establishes a statewide environmental policy and mandates actions all state and local agencies must take to advance the policy. Jurisdictions conduct analysis of the project to determine if there are potentially significant environmental impacts, identify mitigation measures, and possible project alternatives by preparing environmental reports for projects that requires CEQA review. This environmental review is required before an agency takes action on any policy, program, or project.

Santa Clara County has sought exemption from CEQA for the Hazard Mitigation Plan based on four different sections of the CEQA Guidelines:
 Section 15183(d): “The project is consistent with…a general plan of a local agency, and an EIR was certified by the lead agency for the...general plan.”  Section 15262: “A project involving only feasibility or planning studies for possible future actions which the agency, board or commission has not approved, adopted, or funded does not require the preparation of an EIR or negative declaration but does require consideration of environmental factors. This section does not apply to the adoption of a plan that will have a legally binding effect on later activities.”
 Section 15306: “(Categorical Exemption) Class 6 consists of basic data collection, research, experimental management, and resource evaluation activities which do not result in a serious or major disturbance to an environmental resource. These may be strictly for information gathering

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 62 purposes, or as part of a study leading to an action which a public agency has not yet approved, adopted, or funded.”
 Section 15601(b)(3): “...CEQA applies only to projects which have the potential for causing a significant effect on the environment. Where it can be seen with certainty that there is no possibility that the activity in question may have a significant effect on the environment, the activity is not subject to CEQA.”
Planning partners may seek exemption at their discretion.

California Coastal Management Program
The California Coastal Management Program under the California Coastal Act requires each city or county lying wholly or partly within the coastal zone to prepare a local coastal plan. The specific contents of such plans are not specified by state law, but they must be certified by the Coastal Commission as consistent with policies of the Coastal Act (Public Resources Code, Division 20). The Coastal Act has provisions relating to geologic hazards but does not mention tsunamis specifically. Section 30253(1) of the Coastal Act states that new development shall minimize risks to life and property in areas of high geologic, flood, and fire hazard. Development should be prevented or limited in high hazard areas whenever possible. However, where development cannot be prevented or limited, land use density, building value, and occupancy should be kept at a minimum.

There are identified coastal zones in the Santa Clara County Operational Area and affected planning partners have developed local coastal plans to address them. Any mitigation project identified in this plan that intersects the mapped coastal zone will be consistent with the recommendations of the local coastal plan.

California State Assembly Bills
Assembly Bill 162: Flood Planning, Chapter 369, Statutes of 2007 This California State Assembly Bill (AB) passed in 2007 requires cities and counties to address floodrelated matters in the land use, conservation, and safety and housing elements of their general plans.

The land use element must identify and annually review the areas covered by the general plan that are subject to flooding as identified in floodplain mapping by either FEMA or the Department of Water Resources (DWR). During the next revision of the housing element on or after January 1, 2009, the conservation element of the general plan must identify rivers, creeks, streams, flood corridors, riparian habitat, and land that may accommodate floodwater for groundwater recharge and stormwater management. The safety element must identify information regarding flood hazards, including:
 Flood hazard zones;
 Maps published by FEMA, DWR, the U.S. Army Corps of Engineers, the Central Valley Flood.

Protection Board, and CalOES;
 Historical data on flooding; and
 Existing and planned development in flood hazard zones.

The general plan must establish goals, policies, and objectives to protect from unreasonable flooding risks, including:
 Avoiding or minimizing the risks of flooding new development;  Evaluating whether new development should be located in flood hazard zones; and  Identifying construction methods to minimize damage.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 63 Assembly Bill 2140: General Plans—Safety Element, Chapter 739, Statutes of 2006 This bill allows jurisdictions to be eligible for state funding to cover the local match of public assistance costs for recovery activities after hazard events if the local jurisdiction incorporates their Local Hazard Mitigation Plan into the safety element of their general plan. In addition, this bill requires Cal OES to give preference for federal mitigation funding to cities and counties that have adopted local hazard mitigation plans. The intent of the bill is to encourage cities and counties to create and adopt hazard mitigation plans.

The County OEM has worked with the safety element team throughout 2022 and 2023 in updating the Safety Element, to ensure the County is maximizing their future funding opportunities to reduce risk in the County and comply with Assembly Bill 2140 (2006), which affords the county additional benefits under the California Disaster Assistance Act. The Multi-Jurisdictional Hazard Mitigation Plan will be incorporated into the Safety Element as the Safety Element update comes to a completion and is presented to the Board of Supervisors for Adoption.

Assembly Bill 70: Flood Liability, Chapter Number 367, Statutes of 2007 This bill provides that a city or county may be required to contribute a fair and reasonable share to compensate for property damage caused by a flood to the extent that it has increased the state’s exposure to liability for property damage by unreasonably approving new development in a previously undeveloped area that is protected by a state flood control project, unless the city or county meets specified requirements.

Assembly Bill 32: The California Global Warming Solutions Act This bill addresses greenhouse gas emissions. It identifies the following potential adverse impacts of global warming:
the exacerbation of air quality problems, a reduction in the quality and supply of water to the state from the Sierra snowpack, a rise in sea levels resulting in the displacement of thousands of coastal businesses and residences, damage to marine ecosystems and the natural environment, and an increase in the incidences of infectious diseases, asthma, and other human health-related problems.

AB 32 establishes a state goal of reducing greenhouse gas emissions to 1990 levels by 2020 (a reduction of approximately 25 percent from forecast emission levels), with further reductions to follow. The law requires the state Air Resources Board to do the following:35F 36  Establish a program to track and report greenhouse gas emissions.  Approve a scoping plan for achieving the maximum technologically feasible and cost-effective reductions from sources of greenhouse gas emissions.
 Adopt early reduction measures to begin moving forward.  Adopt, implement, and enforce regulations—including market mechanisms such as “cap andtrade” programs—to ensure that the required reductions occur.

The Air Resources Board recently adopted a statewide greenhouse gas emissions limit and an emissions inventory, along with requirements to measure, track, and report greenhouse gas emissions by the industries it determined to be significant sources of greenhouse gas emissions. 36 California Air Resources Board. (2018, September 28). AB 32 Global Warming Solutions Act of 2006. https://ww2.arb.ca.gov/resources/fact-sheets/ab-32-global-warming-solutions-act-2006

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 64 Assembly Bill 2800: Climate Change: Infrastructure Planning This California State Assembly bill, in effect through July 1, 2020, requires state agencies to consider the current and future impacts of climate change when planning, designing, building, operating, maintaining, and investing in state infrastructure. The bill requires the agency to establish a climate-safe infrastructure working group by July 1, 2017, to examine how to integrate scientific data concerning projected climate change impacts into state infrastructure engineering.

Assembly Bill 38: Fire Safety: Low-Cost Retrofits: Regional Capacity Review: Wildfire Mitigation
The Governor approved assembly bill 38 in October 2019 expanding pre-existing obligations to review regional capacity to improve forest health, fire resilience, and safety as well as provide a prescribed disclosure notice to buyers of property informing them of their fire home hardening options. In addition, it authorized Cal OES and CALFIRE to jointly develop a wildfire mitigation program now known as the “Home Hardening Program.” This effort is intended to encourage cost-effective wildfire resilience measures by providing financial assistance for retrofits, hardening, and the creation of defensible space. 1998 Natural Hazard Disclosure Act
The Natural Hazard Disclosure Act, which became effective in June 1998, requires sellers to provide home buyers with a natural hazard disclosure report (NHD) in order to sell a home in a natural hazard zone. Failure to comply with this act may result in the buyer or agent being liable for any damage experienced by the buyer. There are six main hazards required to be disclosed in an NHD:36F 37  A special flood hazard area
 An area of potential flooding on a dam failure inundation map  A very high fire severity zone
 A wildland area that may contain substantial forest fire risks and hazards  An earthquake fault zone
 A seismic hazard zone
California State Senate Bills
Senate Bill 97
Senate Bill 97, enacted in 2007, amends CEQA to clearly establish that greenhouse gas emissions and the effects of greenhouse gas emissions are appropriate subjects for CEQA analysis. It directs the Governor’s Office of Planning and Research to develop draft CEQA guidelines for the mitigation of greenhouse gas emissions or their effects by July 1, 2009, and directs the California Natural Resources Agency to certify and adopt the CEQA Guidelines by January 1, 2010.

Senate Bill 1000 General Plan Amendments: Safety and Environmental Justice Elements Senate Bill 1000 amends California’s Planning and Zoning Law in two ways:
 The original law established requirements for initial revisions of general plan safety elements to address flooding, fire, and climate adaptation and resilience. It also required subsequent review and revision as necessary based on new information. Senate Bill 1000 specifies that the 37 California Association of Realtors. (n.d.). Natural Hazard Disclosure Statement. https://www.car.org/- /media/CAR/Documents/Transaction-Center/PDF/QUICK-GUIDES/Quick-Guide--Natural-Hazard-Disclsoure-NHDStatement-REVISED-52022.pdf

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 65 subsequent reviews and revision based on new information are required to address only flooding and fires (not climate adaptation and resilience).
 Senate Bill 1000 adds a requirement that, upon adoption or revision of any two other general plan elements on or after January 1, 2018, an environmental justice element be adopted for the general plan or environmental justice goals, policies and objectives be incorporated into other elements of the plan.

Senate Bill 1241: General Plans: Safety Element—Fire Hazard Impacts In 2012, Senate Bill 1241 was enacted, requiring that all future General Plans address fire risk in state responsibility areas and very high fire hazard severity zones in their safety element. In addition, the bill requires cities and counties to make certain findings regarding available fire protection and suppression services before approving a tentative map or parcel map.

Senate Bill 379: General Plans: Safety Element—Climate Adaptation Senate Bill 379 builds on the flood planning inclusions into the safety and housing elements and the hazard mitigation planning safety element inclusions in General Plans outlined in AB 162 and AB 2140.

Senate Bill 379 specifically focuses on a new requirement that cities and counties include climate adaptation and resiliency strategies in the safety element of their General Plans beginning January 1, 2017. In addition, this bill requires general plans to include a set of goals, policies, and objectives, and specified implementation measures based on the conclusions drawn from climate adaptation research and recommendations.

This update process for this hazard mitigation plan was conducted with the intention of full compliance with this bill. However, at the time of the update, there was no clear guidance from the state on what constitutes full compliance or what protocol is to be used to determine compliance. When such guidance has been established, the planning partners will submit this plan or its subsequent updates to the state for review and approval.

Senate Bill 190: Fire Safety: Building Standards: Defensible Space Program In October 2019, Senate Bill 190 amended the Government Code and Health and Safety Code to build a common understanding of site and structure fire risk reduction measures. Among other things, the bill authorized the Office of the State Fire Marshall to develop a model defensible space program which would be available for city and county code enforcement officials to utilize. Additionally, it directed the Office of the State Fire Marshall to develop and make publicly available a Wildland-Urban Interface Fire Safety Building Standards compliance training intended for local building officials, builders, and fire service personnel.37 F
38 California State Building Code
California Code of Regulations Title 24 (CCR Title 24), also known as the California Building Standards Code, is a compilation of building standards from three sources:
 Building standards that have been adopted by state agencies without change from building standards contained in national model codes.
 Building standards that have been adopted and adapted from the national model code standards to meet California conditions.
 Building standards authorized by the California legislature that constitute extensive additions not covered by the model codes adopted to address particular California concerns. 38 California Legislative Information. (2019, October 2). SB-190 Fire Safety: Building Standards: Defensible Space Program. Bill Text - SB-190 Fire safety: building standards: defensible space program. (ca.gov)

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 66 The state Building Standards Commission is authorized by California Building Standards Law (Health and Safety Code Sections 18901 through 18949.6) to administer the processes related to the adoption, approval, publication, and implementation of California’s building codes. These building codes serve as the basis for the design and construction of buildings in California. The national model code standards adopted into Title 24 apply to all occupancies in California, except for modifications adopted by state agencies and local governing bodies. Since 1989, the Building Standards Commission has published new editions of Title 24 every 3 years. All municipal planning partners to this plan have adopted building codes that are in full compliance with the California State Building Code.

California has also passed the first green building code in the Nation, known as the California Green Building Standards Code (CALGreen). CALGreen establishes new green building standards in order to promote sustainable development. The goals of the program include:
 Reduce greenhouse gas emissions from buildings.
 Promote environmentally responsible, cost-effective, healthier places to live and work.  Reduce energy and water consumption.
 Respond to the environmental directives of the administration.

Standardized Emergency Management System
CCR Title 19 establishes the Standardized Emergency Management System to standardize the response to emergencies involving multiple jurisdictions. The system is intended to be flexible and adaptable to the needs of all emergency responders in California. It requires emergency response agencies to use basic principles and components of emergency management. Local governments must use the Standardized Emergency Management System by December 1, 1996, to be eligible for state funding of responserelated personnel costs under CCR Title 19 (Sections 2920, 2925 and 2930). The roles and responsibilities of individual agencies contained in existing laws or the state emergency plan are not superseded by these regulations. This hazard mitigation plan is considered to be a support document for all phases of emergency management, including those associated with SEMS.

California State Hazard Mitigation Plan
Under the DMA, California must adopt a federally approved state multi-hazard mitigation plan to be eligible for certain disaster assistance and mitigation funding. California has elected to develop an enhanced plan, which makes it eligible for additional mitigation funding. The State Hazard Mitigation Plan (SHMP) is the State’s primary hazard mitigation guidance. It incorporates:
 An updated analysis of the state’s historical and current hazards.  Hazard mitigation goals and objectives.
 Hazard Mitigation strategies and actions.

The California Governor’s Office of Emergency Services (Cal OES) is responsible for leading the plan update in coordination with key planning stakeholders and sources of information. The 2018 SHMP is being updated at the time of this plan’s update to reflect changing conditions and add new information as well as incorporate the new FEMA planning policy guidance.

Under 44 CFR Section 201.6, local hazard mitigation plans must be consistent with their state’s hazard mitigation plan. In updating this plan, the Steering Committee reviewed the California State Hazard Mitigation Plan to identify key relevant state plan elements.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 67 Governor’s Executive Order S-13-08
Governor’s Executive Order S-13-08 enhances the state’s management of climate impacts from sea level rise, increased temperatures, shifting precipitation and extreme weather events. There are four key actions in the executive order:
 Initiate California’s first statewide climate change adaptation strategy to assess expected climate change impacts, identify where California is most vulnerable, and recommend adaptation policies by early 2009. This effort will improve coordination within state government so that better planning can more effectively address climate impacts on human health, the environment, the state’s water supply and the economy.
 Request that the National Academy of Science establish an expert panel to report on sea level rise impacts in California, to inform state planning and development efforts.  Issue interim guidance to state agencies for how to plan for sea level rise in designated coastal and floodplain areas for new projects.
 Initiate a report on critical infrastructure projects vulnerable to sea level rise.

5.9.3 Local
Plans, Reports, and Codes
Plans, reports, and other technical information were identified and provided directly by participating jurisdictions and stakeholders or were identified through independent research by the planning consultant. These documents were reviewed to identify the following:
 Existing jurisdictional and special district capabilities.  Needs and opportunities to develop or enhance capabilities, which may be identified within the local mitigation strategies.
 Mitigation-related goals or objectives considered during the development of the overall goals and objectives.
 Proposed, in-progress, or potential mitigation projects, actions, and initiatives to be incorporated into the updated mitigation strategies.
 The following local regulations, codes, ordinances, and plans were reviewed in order to develop complementary and mutually supportive goals, objectives, and mitigation strategies that are consistent across local and regional planning and regulatory mechanisms:
▪ General Plans (Housing Elements, Safety Elements).
▪ Building Codes.
▪ Zoning and Subdivision Ordinances.
▪ NFIP Flood Damage Prevention Ordinances.
▪ Stormwater Management Plans.
▪ Emergency Management and Response Plans.
▪ Land Use and Open Space Plans.
▪ Climate Action Plans.
▪ Capability Assessment.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 68 All participating jurisdictions and special districts compiled an inventory and analysis of existing authorities and capabilities called a “capability assessment.” A capability assessment creates an inventory of a jurisdiction’s mission, programs, and policies, and evaluates its capacity to carry them out.

This assessment identifies potential gaps in the jurisdiction’s capabilities and opportunities to expand and improve upon existing capabilities.

The planning partners views all core jurisdictional and special district capabilities as fully adaptable to meet an organization’s needs. Every code can be amended, and every plan can be updated. Such adaptability is itself considered to be an overarching capability. If the capability assessment identified an opportunity to add a missing core capability or expand an existing one, then doing so has been selected as an action in the jurisdiction’s action plan, which is included in the individual annexes presented in Volume 2 of this plan.

Capability assessments for each planning partner are presented in the jurisdictional and special district annexes in Volume 2 of this plan. The sections below describe the specific capabilities evaluated under the assessment.

Legal and Regulatory Capabilities
Jurisdictions have the ability to develop policies and programs and to implement rules and regulations to protect and serve residents. Local policies are typically identified in a variety of community plans, implemented via a local ordinance, and enforced through a governmental body.

Jurisdictions regulate land use through the adoption and enforcement of zoning, subdivision, and land development ordinances, building codes, building permit ordinances, floodplain, and stormwater management ordinances. When effectively prepared and administered, these regulations can lead to hazard mitigation.

Fiscal Capabilities
Assessing a jurisdiction’s or special district’s fiscal capability provides an understanding of the ability to fulfill the financial needs associated with hazard mitigation projects. This assessment identifies both outside resources, such as grant-funding eligibility, and local authority to generate internal financial capability, such as through impact fees.

Administrative and Technical Capabilities
Legal, regulatory, and fiscal capabilities provide the backbone for successfully developing a mitigation strategy; however, without appropriate personnel, the strategy may not be implemented. Administrative and technical capabilities focus on the availability of personnel resources responsible for implementing all the facets of hazard mitigation. These resources include technical experts, such as engineers and scientists, as well as personnel with capabilities that may be found in multiple departments, such as grant writers.

NFIP Compliance
Flooding is the costliest natural hazard in the United States and, with the promulgation of recent federal regulation, homeowners throughout the country are experiencing increasingly high flood insurance premiums. Community participation in the NFIP opens up opportunity for additional grant funding associated specifically with flooding issues. Assessment of the jurisdiction’s current NFIP status and compliance provides planners with a greater understanding of the local flood management program, opportunities for improvement, and available grant funding opportunities.

Public Outreach Capability
Regular engagement with the public on issues regarding hazard mitigation provides an opportunity to directly interface with community members. Assessing this outreach and education capability illustrates

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 5: Santa Clara County Operational Area Profile 69 the connection between the government and community members, which opens a two-way dialogue that can result in a more resilient community based on education and public engagement.

Participation in Other Programs
Other programs, such as the Community Rating System, StormReady, and Firewise, enhance a jurisdiction’s ability to mitigate, prepare for, and respond to natural hazards. These programs indicate a jurisdiction’s desire to go beyond minimum requirements set forth by local, state, and federal regulations in order to create a more resilient community. These programs complement each other by focusing on communication, mitigation, and community preparedness to save lives and minimize the impact of natural hazards on a community.

Development and Permitting Capability
Identifying previous and future development trends is achieved through a comprehensive review of permitting since completion of the previous plan and in anticipation of future development. Tracking previous and future growth in potential hazard areas provides an overview of increased exposure to a hazard within a community.

Adaptive Capacity
An adaptive capacity assessment evaluates a jurisdiction’s ability to anticipate impacts from future conditions. By looking at public support, technical adaptive capacity, and other factors, jurisdictions identify their core capability for resilience against issues such as sea level rise. The adaptive capacity assessment provides jurisdictions with an opportunity to identify areas for improvement by ranking their capacity high, medium, or low.

Expanding and Improving Mitigation Capabilities
Both pre- and post-disaster mitigation capabilities change over time. The intent of this mitigation plan is to evaluate current mitigation capabilities and identify if there are any gaps which could be further addressed. In Volume 2 of this plan, in addition to an individual capability assessment, there is a discussion of the capabilities which could be expanded upon for each participant. County items, such as increasing funding for community education and outreach including translated materials as well as funding regional planning and coordination, serve as examples of what this looks like. If there are any challenges or limitations for each participant, they have stated so in the in their respective annex.

Integration Opportunity
The assessment looked for opportunities to integrate this mitigation plan with the legal/regulatory capabilities identified. Capabilities were identified as integration opportunities if they can support or enhance the actions identified in this plan or be supported or enhanced by components of this plan.

Planning partners considered actions to implement this integration as described in the jurisdictional and special district annexes in Volume 2 of this plan.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 70 6 Identified Hazards of Concern and Risk
Assessment
Risk assessment is the process of measuring the potential loss of life, personal injury, economic injury, and property damage resulting from identified hazards. It allows emergency management personnel to establish early response priorities by identifying potential hazards and vulnerable assets. The process focuses on the following elements:
 Hazard identification: Use all available information to determine what types of hazards may affect a jurisdiction, how often they can occur, and their potential severity.  Exposure identification: Estimate the total number of people and properties in the jurisdiction that are likely to experience a hazard event if it occurs.
 Vulnerability identification and loss estimation: Assess the impact of hazard events on the people, property, environment, economy, and lands of the region, including estimates of the cost of potential damage or cost that can be avoided by mitigation. 
The risk assessment for this hazard mitigation plan update evaluates the risk of natural hazards prevalent in the OA and meets requirements of the Disaster Mitigation Act (44 CFR, Section 201.6(c)(2)).

To protect individual privacy and the security of critical facilities, information on properties assessed is presented in aggregate, without details about specific individual personal or public properties.

6.1 Identified Hazards of Concern
The Core Planning Group considered the full range of natural hazards that could affect the OA and then listed hazards that present the greatest concern. The process incorporated a review of state and local hazard planning documents as well as information on the frequency of, magnitude of, and costs associated with hazards that have struck the OA or could do so. Anecdotal information regarding natural hazards and the perceived vulnerability of the OA’s assets to them was also used. Based on the review, this plan addresses the following hazards of concern (presented in order of the hazard risk index results; the order of listing does not indicate the hazards’ relative severity):
 Earthquake
 Wildfire
 Inclement Weather
 Drought
 Climate Change
 Dam and Levee Failure
 Flood
 Landslide
 Tsunami

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 71 In addition to the hazards of concern for which full risk assessments were performed, other hazards of interest were identified for inclusion in this plan: intentional hazards, technological hazards, and epidemic and pandemic. These hazards are of interest because they present risk to the OA. However, no methodologies are currently available to perform risk assessments on them that are equivalent to those used for the natural hazards of concern addressed in detail in this plan.

6.2 Hazard Risk Index
FEMA requires all hazard mitigation planning partners to have jurisdiction-specific mitigation actions based on local risk, vulnerability, and community priorities (FEMA, 2011). This plan included a risk index procedure for each planning partner, in which the degree of risk posed by each hazard was calculated based on a set of factors.

Risk index factors were assigned a numerical degree of risk level based on information presented in the hazard profiles and planning partner annexes. This number was then weighted, and a formula was used to aggregate the values into an overall hazard risk index number. The weight given to each factor was based on a review of best practices and agreed upon by the Core Planning Team.

All planning partners calculated risk for their own jurisdiction or special district following the same methodology. The higher the overall risk index number, the greater the hazard risk. This methodology does not compare hazards to each other or rank hazards against one another. Instead, this process provides a sense of hazard priorities or relative risk and allows comparison of the same hazard across participants. It provides planning participants with a sense of hazard priorities, or relative risk. By doing this analysis, mitigation planning and initiatives can focus on the greatest risk. While hazards occur together or as a consequence of others (e.g., dam failure may cause flooding and earthquakes may cause landslides), participants considered hazards as a singular event for the purposes of rating. This approach is part of a holistic hazard risk analysis that includes complementary qualitative and quantitative elements and provides a consistent metric across different hazards.

This hazard analysis methodology can:
 Help establish priorities for planning, capability development, and hazard mitigation;  Serve as a tool in the identification of hazard mitigation measures;  Be one tool in conducting a hazard-based needs analysis;  Serve to educate the public and public officials about hazards and vulnerabilities; and  Help communities make objective judgments about acceptable risk.

The factors and their corresponding numeric indices and weight factors are detailed in Table 14.

Individual and OA-level hazard risk indices were used to inform the action plan development process and mitigation priorities for each planning partner. Each annex presents the risk indices for each planning partner.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 72 Table 14: Probability of Hazards
Risk Index
Factor
Degree of Risk
Level Criteria
Factor
Weight for
Degree of
Risk Level
Probability of
Future Events
0 Unlikely
Less than 1 percent probability of occurrence
in the next year or a recurrence interval of
greater than every 100 years.
30%
1 Occasional
1 to 10 percent probability of occurrence in
the next year or a recurrence interval of 11 to
100 years.
2 Likely
11 to 90 percent probability of occurrence in
the next year or a recurrence interval of 1 to
10 years.
3 Highly Likely
91 to 100 percent probability of occurrence in
the next year or a recurrence interval of less
than 1 year.

Life Impact
0 Minor Very few injuries, if any at all.
35%
1 Limited Minor injuries.
2 Critical Multiple deaths and/or injuries.
3 Catastrophic High number of deaths and/or injuries.

Property Impact
0 Minor
Only minor property damage and minimal
disruption of life. Temporary shutdown of
critical facilities.
25%
1 Limited
More than 10 percent of property in affected
area damaged/destroyed. Complete
shutdown of critical facilities for more than
one day.
2 Critical
More than 25 percent of property in affected
area damaged/destroyed. Complete
shutdown of critical facilities for more than
one week.
3 Catastrophic
More than 50 percent of property in affected
area damaged/destroyed. Complete
shutdown of critical facilities for 30 days or
more.

Percentage of
Area Impacted
0 Negligible Less than 10 percent of planning area or
isolated single-point occurrences.
10%
1 Minimal 10 to 25 percent of the planning area or
limited single-point occurrences.
2 Significant 26 to 74 percent of planning area or frequent single-point occurrences.
3 Extensive 75 to 100 percent of planning area or
consistent single-point occurrences.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 73 Table 15: Hazard Risk Ranking by Jurisdiction
Earthquake Wildfire Inclement
Weather Drought Climate Change
Dam and
Levee Failure Flood Landslide Tsunami
Campbell 2 0.9 1.7 0.7 0 1.75 0.55 0 0
Cupertino 2.7 1.9 1.1 1.45 1.55 0.45 0.5 0.4 0
Gilroy 2.9 1.05 1.25 0.9 0.3 2 0.4 0 0
Los Altos 2 1.95 2.05 1.8 1.6 0.95 0.65 0 0
Los Altos Hills 2 2.1 1.4 1.95 1.3 0 0.65 1.3 0
Los Gatos 1.45 2.55 1.15 0.6 1.2 0.35 0.35 0.65 0
Milpitas 2.3 2.05 0.9 1.2 2.3 1.85 1.8 0.6 0
Monte Sereno - - - - - - - - -
Morgan Hill 2.9 1.05 1.25 0.9 0.3 2 1.25 0 0
Mountain
View
2 0.65 1.4 2 1.3 0 2 0 0
Palo Alto 2 1.95 2.05 2.05 1.85 0.95 0.65 0 0
San Jose 1.25 1.6 1.8 1.45 0 1.9 1.9 0 0
Santa Clara
City
3 1.3 1.7 1.45 1.4 1.8 2 0 0.35
Saratoga 2.7 2 0.95 0.8 0.4 0 0 0.85 0
Sunnyvale 2.9 1.05 1.25 0.9 0.3 2 0.3 0 0
Santa Clara
County

2.1 1.7 1.55 0.8 1.6 1.75 0.65 0.4 0
SCC 2.1 1.7 1.55 0.8 1.6 1.75 0.65 0.4 0
MidPen 1.35 3 1.3 1.2 1.8 0.25 1.2 1.55 0
SCCFD 2.7 1.7 1.55 0.8 1.6 1.75 0.65 0.4 0

SCVWD - - - - - - - - -
Average 2.24 1.68 1.44 1.21 1.13 1.19 0.90 0.36 0.02

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 74

6.2.1 Average Overall Hazard Risk Index Results
The overall hazard risk index results based on an average of partner indices is shown in Table 16. These results show which hazards pose the highest overall risk to the Operational Area.

Table 16: Average Overall Hazard Risk Index Results
Hazard Risk Order Hazard Average Overall Hazard Risk
Index Result
1 Earthquake 2.24
2 Wildfire, smoke, and air quality 1.68
3 Inclement weather* 1.44
4 Drought 1.21
5 Climate change, including sea-level
rise

1.13 6 Dam and levee failure 1.19
7 Flood .90
8 Landslide and mass movement .36
9 Tsunami .02
*Listed as separate hazards in the hazard profile and annexes: heavy precipitation, high wind, extreme heat, extreme cold, and space weather.

Based on the average overall hazard risk index results from planning partner risk indices:
• The earthquake hazard has the highest risk results, followed by wildfire/smoke/air quality.  The inclement weather, drought, climate change hazards were a moderate risk to the Operational Area.
 The dam failure, flood, and landslide/mass movement hazards were a lower risk to the Operational Area.
 The tsunami hazard poses the lowest risk to the Operational Area, as not all planning partners can be impacted by this hazard due to geographic location.

6.3 Risk Assessment Tools

6.3.1 Mapping
National, state, and county databases were reviewed to locate available spatially based data relevant to this planning effort. Maps were produced using geographic information system (GIS) software to show the spatial extent and location of hazards when such datasets were available. These maps are included in the hazard profile sections and planning partner annexes of this MJHMP.

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6.3.2 Hazus
Overview
In 1997, FEMA developed the standardized Hazards U.S. (Hazus) model to estimate losses caused by earthquakes and identify areas that face the highest risk and potential for loss. Hazus was later expanded into a multi-hazard methodology with new models for estimating potential losses from hurricanes and floods.

Hazus is a GIS-based software program used to support risk assessments, mitigation planning, and emergency planning and response. It provides a wide range of inventory data, such as demographics, building stock, critical facility, transportation and utility lifeline, and multiple models to estimate potential losses from natural disasters. The program maps and displays hazard data and the results of damage and economic loss estimates for buildings and infrastructure. Its advantages include the following:
 Provides a consistent methodology for assessing risk across geographic and political entities.  Provides a way to save datasets so that they can readily be updated as population, inventory, and other factors change and as mitigation planning efforts evolve.  Facilitates review of mitigation plans because it helps to ensure that FEMA methodologies are incorporated.
 Supports grant applications by calculating benefits using FEMA definitions and terminology.  Produces hazard data and loss estimates that can be used in communication with local stakeholders.
 Is administered by the local government and can be used to manage and update a hazard mitigation plan throughout its implementation.

Levels of Detail for Evaluation
Hazus provides default data for inventory, vulnerability, and hazards; the default data can be supplemented with local data to provide a more refined analysis. The model can carry out three levels of analysis, depending on the format and level of detail of information about the OA:
 Level 1: All of the information needed to produce an estimate of losses is included in the software’s default data. These data are derived from national databases and describe in general terms the characteristic parameters of the OA.
 Level 2: More accurate estimates of losses require more detailed information about the OA. To produce Level 2 estimates of losses, detailed information is required about local geology, hydrology, hydraulics, and building inventory, as well as data about utilities and critical facilities.

This information is needed in a GIS format.
 Level 3: This level of analysis generates the most accurate estimate of losses. It requires detailed engineering and geotechnical information to customize it for the OA.

6.4 Risk Assessment Approach
The risk assessments in this plan describe the risks associated with each identified hazard of concern.

The following steps were used to define the risk of each hazard:
 Identify and profile each hazard: The following information is given for each hazard:
▪ Geographic areas most affected by the hazard.
▪ Event frequency estimates.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 76 ▪ Severity estimates.
▪ Warning time likely to be available for response.
 Define probability: probability of future events was identified utilizing the following terms:
▪ Unlikely – less than 1 percent probability of occurrence in the next year or a recurrence interval of greater than every 100 years.
▪ Occasional – 1 to 10 percent probability of occurrence in the next year or a recurrence interval of 11 to 100 years.
▪ Likely – 11 to 90 percent probability of occurrence in the next year or a recurrence interval of 1 to 10 years.
▪ Highly Likely – 91 to 100 percent probability of occurrence in the next year or a recurrence interval of less than 1 year.
 Determine exposure to each hazard: Exposure was assessed by overlaying hazard maps with an inventory of structures, facilities, and systems to decide which of them would be exposed to each hazard.
 Assess the vulnerability of exposed facilities: Vulnerability of exposed structures and infrastructure was evaluated by interpreting the probability of occurrence of each event and assessing structures, facilities, and systems that are exposed to each hazard. Tools such as GIS and Hazus were used for this assessment for the flood and earthquake hazards. Outputs similar to those from Hazus were generated for other hazards, using data generated through GIS.

6.4.1 Earthquake and Flood
The following hazards were evaluated using Hazus:
 Flood: A Level 1 user-defined analysis was performed for general building stock in flood zones and for critical facilities and infrastructure. Digital Elevation Models (DEM) for the OA was used to delineate flood hazard areas and estimate potential losses from the 10-percent-annual-chance, 1- percent-annual-chance, and 0.2-percent-annual-chance flood events. To estimate damage that would result from a flood, Hazus uses pre-defined relationships between flood depth at a structure and resulting damage, with damage given as a percent of total replacement value.

Curves defining these relationships have been developed for damage to structures and for damage to typical contents within a structure. By inputting flood depth data and known property replacement cost values, dollar-value estimates of damage were generated.  Earthquake: A Level 2 analysis was performed to assess earthquake exposure and vulnerability for three scenario events and two probabilistic events:
▪ A Magnitude-7.0 event on the Hayward Fault with an epicenter approximately 25 miles north of the City of Palo Alto.
▪ A Magnitude-7.0 event on the Calaveras Fault with an epicenter approximately 25 miles north of the City of Milpitas.
▪ A Magnitude-7.8 event on the San Andreas Fault with an epicenter approximately 148 miles northwest of the City of Palo Alto.
▪ The standard Hazus 100- and 500-year probabilistic events.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 77

6.4.2 Drought
The risk assessment methodologies used for this plan focus on damage to structures. The risk assessment for drought was more limited and qualitative than the assessment for the other hazards of concern because drought does not affect structures.

6.4.3 All Other Assessed Hazards
Historical datasets were not adequate to model future losses for most of the hazards of concern.

However, areas and inventory susceptible to some of the hazards of concern were mapped by other means and exposure was evaluated. A qualitative analysis was conducted for other hazards using the best available data and professional judgment.

6.5 EMAP Consequence Analysis
A consequence analysis of the potential for detrimental impacts of hazards is included in this 2023 plan update for the Emergency Management Accreditation Program (EMAP). Each hazard identified in this plan is followed by the Consequence Analysis result.

In this analysis all nine natural hazards profiled for Santa Clara County have been addressed, with the impacts that each will have on the following:
 Impact on the Public: What is the scope of impact on the health and safety of people in the area of the incident?
 Impact on Responders: What is the scope of impact on health and safety of responders (i.e., firefighters, law enforcement, emergency management personnel, etc.) in the area responding to the incident?
 Continuity of Operations: Will the organization need to relocate in order to fulfill duties? Will any other continuity measures be implemented?
 Impact on Property, Facilities, and Infrastructure: What are potential damages to structures (private and public), utilities, treatment plants, electric grid, roads, and bridges?  Delivery of Services: What impacts occur to the delivery of services such as food, medical, or any other life sustaining entities?
 Impact on the Environment: How has the incident affected the surrounding environment, i.e., contamination (water, soil, or air), erosion, crop damage, etc.?  Impact on the Economy: Are there any affects to the economy due to loss of revenue, cleanup efforts, and reconstruction?
 Impact of the Public Confidence in the Jurisdiction’s Governance: How has the hazard affected public confidence?
The Consequence Analysis includes ranking determinations for each of the above elements. The ranking elements are categorized as Minimal, Moderate, or Severe. The Risk Assessment portion of the MJHMP was used to ascertain prior damages in an effort to estimate ratings on future impacts. The ratings are meant to be a guide, and not all inclusive, due to the variances that could apply such as population, location, time, hazard type, and the number of jurisdictions within the hazard area.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 78

6.6 Sources of Data Used in Hazus Modeling

6.6.1 Building and Cost Data
Replacement cost values and detailed structure information and census data are included within Hazus

6.0. This recently updated version of Hazus uses 2020 census data and dasymetric census blocks for improved floodplain model accuracy. The stock building inventory data is from the National Structure Inventory (NSI), a point-based dataset developed by the U.S. Army Corps of Engineers (USACE). When available, updated data provided by Santa Clara County was used in place of the Hazus defaults for critical facilities and infrastructure.

Replacement cost is the cost to replace the entire structure with one of equal quality and utility.

Replacement cost is based on industry-standard cost-estimation models published in RSMeans Square Foot Costs.38F
39 It is calculated using the RSMeans square foot cost for a structure, which is based on the Hazus occupancy class (i.e., multi-family residential or commercial retail trade), multiplied by the square footage of the structure from the tax assessor data. The construction class and number of stories for single-family residential structures also factor into determining the square foot costs.

6.6.2 Hazus Data Inputs
The following hazard datasets were used for the Hazus Level 2 analysis conducted for the risk assessment:
 Flood: A USGS 10-meter Digital Elevation Model for the OA was used to delineate flood hazard areas and generate flood depth grids that are integrated into the Hazus model. These depth grids are used to estimate potential losses from the 10-percent-annual-chance, 1-percent-annualchance, and 0.2-percent-annual-chance flood events.  Earthquake: Earthquake ShakeMaps and probabilistic data prepared by the USGS were used for the analysis of this hazard. A National Earthquake Hazard Reduction Program soils map from the California Department of Conservation, USGS liquefaction susceptibility data and susceptibility to deep-seated landslide from the California Geological Survey were also integrated into the Hazus model. Hazus uses classifications within these datasets to derive probabilities that ground deformation can occur in areas of higher liquefaction or landslide susceptibility. It should be noted that deep-seated landslides are generally large landslides that are slow moving during rainfall induced movement, but some can be fast moving and may occur during earthquakes. However, this dataset does not specifically measure earthquake induced landslides. Inclusion of liquefaction and landslide data in Hazus represent ground deformation that may occur during an earthquake that can contribute to structural damage. As such, inclusion of these datasets tends to increase the amount and cost of damage modeled by Hazus.

6.6.3 Other Local Hazard Data
Locally relevant information on hazards was gathered from a variety of sources. Frequency and severity indicators include past events and the expert opinions of geologists, emergency management specialists, and others. Data sources for specific hazards were as follows:
 Landslide: Susceptibility to deep-seated landslide data were provided by the California Geological Survey.
39 RSMeans data from Gordian. (2023). Estimating Square Foot Cost. https://www.rsmeans.com/estimating-squarefoot-cost

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 79  Sea Level Rise: Sea level rise data were provided by the San Francisco Bay Conservation and Development Commission. A sea level rise of 6 feet above current mean higher high water was used for the exposure analysis.
 Dam Inundation: Dam inundation exposure areas were acquired from the California Department of Water Resources Division of Safety of Dams. Many of these are owned by the Santa Clara Valley Water District.
 Levee Inundation: Levee inundation exposure areas were defined with boundaries provided by Santa Clara County.
 Severe Storm: No GIS format severe storm area datasets were identified for the OA.  Tsunami: Tsunami inundation map was prepared by California Department of Conservation in cooperation with the University of Southern California, California Geological Survey, and California Emergency Management Agency.
 Wildfire: Wildfire Hazard Classification and Structures at Risk data were provided by Tukman Geospatial. Additional fire severity data was acquired from California Department of Forestry and Fire Protection (CAL FIRE).

6.6.4 Data Source Summary
Table 17 summarizes the data sources used for the risk assessment for this plan.

Table 17: Hazus Model Data Documentation
Data Source Date Format
Building information such as area,
occupancy, date of construction,
and stories
FEMA Hazus version 6.0,
National Structure Inventory
(NSI), Santa Clara County
2023 Digital (tabular)
format
Building replacement cost FEMA Hazus version 6.0 2023 Digital (GIS and tabular) format
Population data FEMA Hazus version 6.0, US
Census Bureau
2020 Digital (GIS and
tabular) format
Flood hazard data FEMA 2016 Digital (GIS)
format
Tsunami CGS (State of California) 2021 Digital (GIS)
format
Earthquake ShakeMaps USGS, provided via Hazus
version 6.0
Downloaded
2023
Digital (GIS)
format
Liquefaction susceptibility USGS (via ABAG) 2006 Digital (GIS) format
National Earthquake Hazard
Reduction Program
California Department of
Conservation, California
Geological Survey
Downloaded
2023
Digital (GIS)
format
Dam Inundation Areas California Department of
Water Resources, Division of
Safety of Dams
Varies
2019-2021
Digital (GIS)
format
Landslide California Geological Survey 2011 Digital (GIS) format

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 80 Data Source Date Format
Sea Level Rise Adapting to Rising Tides -
San Francisco Conservation
and Development
Commission
2018 Digital (GIS)
format
Wildfire Tukman Geospatial, CAL
FIRE
2022, 2007 Digital (GIS)
format
Digital Elevation Model USGS Downloaded
2023
Digital (GIS)
format
Critical Facilities and Assets Hazus version 6.0, Santa Clara County
2023 Digital (GIS)
format
Emergency operation centers,
airport facilities, bus facilities, light
rail facilities, rail facilities,
communication facilities, electric
power facilities, potable water
facilities, wastewater facilities
FEMA Hazus version 6.0
Default Critical Facilities Data
2023 Digital (GIS)
format
Points of interest (city halls,
community centers, other county
facilities, child day care facilities)
Santa Clara County 2023 Digital (GIS)
format
Santa Clara County critical facilities
(fire stations, hospitals, skilled
nursing facilities and clinics, police
stations, public / private schools,
universities, and colleges)
FEMA Hazus version 6.0,
Santa Clara County
2023 Digital
(spreadsheet)
format
Superfund sites (hazardous material
sites)
EPA 2022 Digital (GIS)
format
Toxic release inventory facilities
(hazardous material facilities,
designated communications
centers, electric power, and
petroleum facilities)
Environmental Protection
Agency (EPA)
Downloaded
2023
Digital (GIS)
format
State and local bridges (highway
bridges, light rail bridges, rail
bridges, includes pedestrian
bridges)
Hazus 6.0 Inventory, Santa
Clara County
2023 Digital (GIS)
format

6.7 Limitations
Loss estimates, exposure assessments, and hazard-specific vulnerability evaluations rely on the best available data and methodologies. Uncertainties are inherent in any loss estimation methodology and arise in part from incomplete scientific knowledge concerning natural hazards and their effects on the built environment. Uncertainties also result from the following:
 Approximations and simplifications necessary to conduct a study.  Incomplete or outdated inventory, demographic or economic parameter data.  The unique nature, geographic extent, and severity of each hazard.  Mitigation measures already employed.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 6: Identified Hazards of Concern and Risk Assessment 81  The amount of advance notice residents have to prepare for a specific hazard event.  Lack of a standardized model for assessing sea level rise impacts. Multiple models provide multiple results. Not all models were run in the development of the sea level rise analysis.

These factors can affect loss estimates by a factor of two or more. Therefore, potential exposure and loss estimates are approximate and should be used only to understand relative risk. Over the long term, Santa Clara County will collect additional data to assist in estimating potential losses associated with other hazards.

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Santa Clara County Multijurisdictional Hazard Mitigation Plan—DRAFT Section 7: Earthquakes 82
7 Earthquake
Definitions
 Earthquake: The shaking of the ground caused by an abrupt shift of rock along a fracture in the earth or a contact zone between tectonic plates.
 Epicenter: The point on the earth’s surface directly above the hypocenter of an earthquake. The location of an earthquake is commonly described by the geographic position of its epicenter and by its focal depth.
 Fault: A fracture in the earth’s crust along which two blocks of the crust have slipped with respect to each other.
 Hypocenter: The region underground where an earthquake’s energy originates.  Liquefaction: Loosely packed, water-logged sediments losing their strength in response to strong shaking, causing major damage during earthquakes.

7.1 General Background
An earthquake is the vibration of the earth’s surface following a release of energy in the earth’s crust. This energy can be generated by a sudden dislocation of the crust or by a volcanic eruption. Most destructive quakes are caused by dislocations of the crust. The crust may first bend and then, when the stress exceeds the strength of the rocks, break and snap to a new position. In the process of breaking, vibrations called “seismic waves” are generated. These waves travel outward from the source of the earthquake at varying speeds.

Geologists have found that earthquakes tend to reoccur along faults, which are zones of weakness in the earth’s crust. Even if a fault zone has recently experienced an earthquake, there is no guarantee that all the stress has been relieved. Another earthquake could still occur. In fact, relieving stress can increase stress in other parts of the affected fault and other faults. Additional earthquakes, called aftershocks, are common after a large earthquake.

California is seismically active because of movement of the North American Plate, east of the San Andreas Fault, and the Pacific Plate to the west, which includes the state’s coastal communities.

Movement of the tectonic plates against one another creates stress, which is released as energy that moves through the earth as seismic waves.

Faults are classified in terms of their activity level; “active,” “potentially active,” or “inactive.” Most seismic activity occurs along faults that are known to have geologic evidence of activity. However, inactive faults, where no such displacements have been recorded, also have the potential to reactivate or experience displacement along a branch sometime in the future. An example of a fault zone that has been reactivated is the Foothills Fault Zone. The zone was considered inactive until evidence of an earthquake (approximately 1.6 million years ago) was found near Spenceville, California. Then, in 1975, an earthquake occurred on another branch of the zone near Oroville, California (now known as the Cleveland Hills Fault). The State Division of Mines and Geology indicates that increased earthquake activity throughout California may cause tectonic movement along currently inactive fault systems.

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7.1.1 Damage from Earthquakes
A direct relationship exists between a fault’s length and location and its ability to generate damaging ground motion at a given site. Small, local faults produce lower magnitude quakes, but ground shaking can still be strong, and damage can be significant in areas close to the fault. In contrast, large regional faults can generate earthquakes of great magnitudes but, because of their distance and depth, they may result in only moderate shaking in an area.

Earthquakes can last from a few seconds to over five minutes; they may also occur as a series of tremors over a period of several days. Aftershocks may be felt for months or years after the mainshock. The actual movement of the ground in an earthquake is seldom the direct cause of injury or death. People that fall over during the quake may experience more mild injuries like broken bones. Casualties generally result from falling objects and debris, because earthquakes shake, damage, or demolish furnishings and buildings and other structures. Disruption of communications and internet, electrical power, gas, sewer, and water services should be expected in the affected area. Earthquakes may trigger dam failures and landslides. Their damage may cause fires and releases of hazardous material, compounding the disastrous effects.

7.1.2 Earthquake Classifications
Earthquakes are typically classified in one of two ways: by the amount of energy released, measured as magnitude; or by the impact on people and structures, measured as intensity.

Magnitude
An earthquake’s magnitude is a measure of the energy released at the source of the earthquake. It is commonly expressed by ratings on either of two scales (Michigan Tech University)39F 40:
 The Richter scale measures magnitude of earthquakes based on the amplitude of the largest energy wave released by the earthquake. Richter scale readings are suitable for smaller earthquakes; however, because it is a logarithmic scale, the scale does not distinguish clearly the magnitude of large earthquakes above a certain level. Richter scale magnitudes and corresponding earthquake effects are as follows:
▪ 2.5 or less: Usually not felt, but can be recorded by seismograph. ▪ 2.5 to 5.4: Often felt, but causes only minor damage. ▪ 5.5 to 6.0: Slight damage to buildings and other structures. ▪ 6.1 to 6.9: May cause a lot of damage in very populated areas. ▪ 7.0 to 7.9: Major earthquake; serious damage.
▪ 8.0 or greater: Great earthquake; can totally destroy communities near the epicenter. 40 Michigan Tech University. (n.d.) How do we measure Earthquake Magnitude? https://www.mtu.edu/geo/community/seismology/learn/earthquake-measure/

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 While the Richter scale may be well known, the most commonly used scale today is the moment magnitude (Mw) scale. The moment magnitude scale is based on the total moment release of the earthquake (the product of the distance a fault moved, and the force required to move it).

Moment magnitude roughly matches the Richter scale but provides more accuracy for larger magnitude earthquakes. The scale is as follows:
▪ Great: Mw > 8.
▪ Major: Mw = 7.0 - 7.9.
▪ Strong: Mw = 6.0 - 6.9.
▪ Moderate: Mw = 5.0 - 5.9.
▪ Light: Mw = 4.0 - 4.9.
▪ Minor: Mw = 3.0 - 3.9.
▪ Micro: Mw < 3.

Intensity
For an earthquake, intensity varies across the area. Intensity will be larger near the fault rupture, in the direction of the rupture, and in sedimentary basins. Sedimentary basins are depressions in the earth’s surface that consist of alluvial deposit and sedimentary rocks, which are geologically younger and have slower seismic wave velocities.40F
41 Sedimentary basins like the Evergreen basin, which lies beneath the northeastern margin of the Santa Clara Valley near the south end of the San Francisco Bay, amplify the ground shaking during an earthquake, increasing the intensity of the quake. Currently the most commonly used intensity scale is the Modified Mercalli Intensity (MMI) Scale, with ratings defined in Figure 19.41F 42 41 U.S. Geological Survey. (2020). Earthquake Science Center Seminars, Sedimentary basin effects in ground motions from empirical models and simulation platforms. https://earthquake.usgs.gov/contactus/menlo/seminars/1297#:~:text=Sedimentary%20basins%20are%20depressions %20in,in%20thickness%20towards%20their%20margins.
42 U.S. Geological Survey. (n.d.). The Modified Mercalli Intensity (MMI) Scale assigns intensities as…. https://www.usgs.gov/media/images/modified-mercalli-intensity-mmi-scale-assigns-intensities

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Figure 20: Modified Mercalli Intensity Scale42F
43 7.1.3 Ground Motion
Earthquake hazard assessment is also based on expected ground motions. During an earthquake when the ground is shaking, it experiences acceleration. The peak ground acceleration (PGA) is the largest increase in velocity recorded by a particular station during an earthquake. PGA indicates the severity of an earthquake and is a measure of how hard the earth shakes, or accelerates, in a given geographic area. It is measured in g (the acceleration due to gravity), expressed as a percentage of that acceleration (%g). Horizontal and vertical PGA varies with soil or rock type. Instruments called accelerographs record levels of ground motion due to earthquakes at stations throughout a region. These readings are recorded by state and federal agencies that monitor and predict seismic activity. Earthquake hazard assessment involves estimating the annual probability that certain ground motion accelerations will be exceeded, and then summing the annual probabilities over the time period of interest.

National maps of earthquake shaking hazards, which have been produced since 1948, provide information for creating and updating seismic design requirements for building codes, insurance rate structures, earthquake loss studies, retrofit priorities and land use planning. After thorough review of the studies, professional organizations of engineers update the seismic-risk maps and seismic design requirements contained in building codes, the USGS updated the National Seismic Hazard Maps in 2018. 43 U.S. Geological Survey. (n.d.). The Modified Mercalli Intensity (MMI) Scale Assigns Intensities as... https://www.usgs.gov/media/images/modified-mercalli-intensity-mmi-scale-assigns-intensities

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New seismic, geologic, and geodetic information on earthquake motion, soil amplification factors, and local seismic velocity models was incorporated into the revised maps, allowing the USGS, for the first time, to calculate probabilistic seismic hazard curves for an expanded time period and site classes as well as account for long-period ground motions in deep sedimentary basins like the San Francisco Bay region.43F
44 The USGS is currently working on updating this model with a targeted release later in 2023.

These maps influence earthquake insurance rates and support government official, emergency managers, community planners, and the public in understanding the potential risks to their community.

Building codes that include seismic provisions specify the horizontal force due to lateral acceleration that a building should be able to withstand during an earthquake. Buildings, bridges, highways, and utilities built to meet modern seismic design requirements are typically able to withstand earthquakes better, with less damage and disruption. PGA values are directly related to these lateral forces that could damage “short period structures” (e.g., single-family dwellings). Longer-period response components determine the lateral forces that damage taller structures with longer natural periods (apartment buildings, factories, high-rises, bridges). Figure 20 lists damage potential and perceived shaking by PGA factors, compared to the Mercalli scale.

Figure 21: Peak Acceleration (%g) with 10% Probability of Exceedance in 50 Years4F 45 44 U.S. Geological Survey. (2021, September 23). Data Release for Additional Period and Site Class Data for the 2018 National Seismic Hazard Model for the Conterminous United States. https://www.usgs.gov/data/data-releaseadditional-period-and-site-class-data-2018-national-seismic-hazard-model 45 U.S. Geological Survey. (2018). 2018 Long-term National Seismic Hazard Map. https://www.usgs.gov/media/images/2018-long-term-national-seismic-hazard-map

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Table 18: Mercalli Scale and Peak Ground Acceleration Comparison45F 46 Modified
Mercalli
Scale
Perceived
Shaking
Potential Structure Damage
Estimated PGAa
Resistant (%g)
Buildings
Vulnerable
Buildings
I Not Felt None None <0.17%
II-III Weak None None 0.17% - 1.4%
IV Light None None 1.4% - 3.9%
V Moderate Very Light Light 3.9% - 9.2%
VI Strong Light Moderate 9.2% - 18%
VII Very Strong Moderate Moderate/Heavy 18% - 34%
VIII Severe Moderate/Heavy Heavy 34% - 65%
IX Violent Heavy Very Heavy 65% - 124%
X - XII Extreme Very Heavy Very Heavy >124%
a PGA measured in percent of g, where g is the acceleration of gravity.

7.1.4 Effect of Soil Types
The impact of an earthquake on structures and infrastructure is largely a function of ground shaking, distance from the source of the quake, and liquefaction, a secondary effect of an earthquake in which soils lose their shear strength and flow or behave as liquid, thereby damaging structures that derive their support from the soil. Liquefaction generally occurs in soft, unconsolidated sedimentary soils and shallow water table.

A program called the National Earthquake Hazard Reduction Program (NEHRP) creates maps based on soil characteristics to help identify locations subject to liquefaction. Table 19 summarizes NEHRP soil classifications. NEHRP Soils B and C typically can sustain ground shaking without much effect, dependent on the earthquake magnitude. The areas that are commonly most affected by ground shaking have NEHRP Soils D, E, and F. In general, these areas are also most susceptible to liquefaction.

Table 19: National Earthquake Hazard Reduction Program Soil Classification System46F 47 NEHRP Soil Type Description
Mean Shear
Velocity to 30 m
(m/s)
A Hard Rock 1,500
B Firm to Hard Rock 760–1,500
C Dense Soil/Soft Rock 360–760
D Stiff Soil 180–360
E Soft Clays < 180
46 SanAndreasFault.org. (2010). Did you feel it? http://www.sanandreasfault.org/feelit.html 47 National Earthquake Hazard Reduction Program. (n.d.). Seismic Site Classification. https://www.masw.com/files/NEHRP.pdf

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NEHRP Soil Type Description
Mean Shear
Velocity to 30 m
(m/s)
F Special Study Soils (liquefiable soils, sensitive clays, organic soils, soft clays >36 m thick)
The USGS has created a soil type map for the San Francisco Bay area that provides rough estimates of site effects based on surface geology. NEHRP soil types were assigned to a geologic unit based on the average velocity of that unit, and the USGS notes that this approach can lead to some inaccuracy. For instance, a widespread unit consisting of Quaternary sand, gravel, silt, and mud has been assigned as Class C soil types; however, some of the slower soil types in this unit fall under Class D. USGS does not have any way of differentiating units for slower-velocity soils in its digital geologic dataset.47F 48 7.2 Hazard Profile
The Bay region is located within the active boundary between the Pacific and the North American tectonic plates. The western edge of the Santa Clara County OA is on the Pacific Plate, which is constantly moving northwest past the North American Plate at a rate of about 2 inches per year.48F 49 Earthquakes in
the San Francisco Bay region result from strain energy constantly accumulating across the region because of the motion of the Pacific Plate relative to the North American Plate. The San Andreas Fault, on which earthquakes of magnitude 7.8 and 7.9 have occurred in historical time, including the 1906 San Francisco earthquake, is the fastest slipping fault along the plate boundary.

7.2.1 Past Events
The last major earthquake with an epicenter in the Santa Clara County OA was the 1984 Morgan Hill Earthquake (Magnitude 6.2). The epicenter of the 1989 Loma Prieta Earthquake (Magnitude 7.1) was just a few miles outside the OA. Since then, there have been no significant seismic events in Santa Clara County.49F
50 Other significant earthquakes in California include the 1906 earthquake in San Francisco, the 1971 San Fernando Earthquake, the 1994 Northridge earthquake, the 2014 Napa earthquake, and the 2019 Ridgecrest earthquake.

The Morgan Hill Earthquake of April 24, 1984, was a moderate size earthquake on the Calaveras Fault. It caused moderate damage that extended southward from the epicenter. In the Santa Clara County OA, where most of the damage occurred, more than 550 structures experienced minor damage. Major structural damage was mostly confined to a small area on two streets in the Jackson Oaks subdivision east of Morgan Hill. There were numerous reports of fires resulting from the earthquake. Minor damage was also reported in San Martin and Coyote. Twenty-seven people were injured.50 F 51 This event led to a
FEMA major disaster declaration (DR-845).
48 U.S. Geological Survey. (2006). Geologic Map of the San Francisco Bay Region. https://pubs.usgs.gov/sim/2006/2918/sim2918_geolposter-stdres.pdf 49 U.S. Geological Survey. (n.d.). Earthquake Facts & Earthquake Fantasy. https://www.usgs.gov/programs/earthquake-hazards/earthquake-facts-earthquakefantasy#:~:text=The%20Pacific%20Plate%20moves%20northwestward%20past%20the%20North,tiny%20shocks%2 0and%20a%20few%20moderate%20earth%20tremors.
50 Association of Bay Area Governments. (n.d.). Resilience. https://abag.ca.gov/our-work/resilience 51 Association of Bay Area Governments. (2011). Bay Area Local Hazard Mitigation Plan Taming Natural Hazards. https://abag.ca.gov/2011-bay-area-hazard-mitigation-plan

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The Loma Prieta Earthquake on October 17, 1989, occurred near Loma Prieta in the Santa Cruz Mountains along the San Andreas Fault. Thousands of landslides across the area blocked roads and highways, impacting rescue efforts and damaging structures. In Santa Clara County, collapsed and damaged buildings were reported in Gilroy, Los Gatos, and San José.51F 52 California has been included in 13 FEMA major disaster (DR) or emergency (EM) declarations for earthquakes. Santa Clara County was included in only one declaration: DR-845 for the Loma Prieta Earthquake, which occurred in 1989. The declaration for this event covered Alameda, Contra Costa, Marin, Monterey, Sacramento. Table 20 and Figure 21 summarize recent earthquakes of magnitude of

5.0 or greater within a 100-mile radius of the OA.

Table 20: Recent Earthquakes Magnitude 5.0 or Larger Within a 100-Mile Radius of the Operational Area
Date Magnitude Epicenter Location
10/25/2022 5.1 9 miles east-southeast of Alum Rock, California 4/5/2018 5.3 19 miles southwest of Santa Cruz, California 8/24/2014 6.0 South Napa, California
10/21/2012 5.3 15 miles east-northeast of King City, California 10/31/2007 5.5 San José, California
5/14/2002 5.0 Northern California
9/3/2000 5.0 Northern California
8/12/1998 5.2 Central California
4/18/1990 5.4 Northern California
10/17/1989 6.9 Loma Prieta, California Earthquake
10/18/1989 5.1 4 miles southwest of Monte Sereno, California 8/8/1989 5.4 Northern California
6/27/1989 5.3 Northern California
6/13/1988 5.3 San Francisco Bay Area, California
2/20/1988 5.1 Central California
3/31/1986 5.7 Northern California
1/26/1986 5.4 Central California
52 Association of Bay Area Governments. (2011). Bay Area Local Hazard Mitigation Plan Taming Natural Hazards. https://abag.ca.gov/2011-bay-area-hazard-mitigation-plan

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Figure 22: Historic Earthquakes in the Operational Area

7.2.2 Location
Santa Clara County is exposed to three major regional faults: Hayward, Calaveras, and San Andreas.

The Hayward and Calaveras faults are in the central portion of Santa Clara County and present the greatest earthquake threat to the OA. The San Andreas Fault is on the northwestern boundary of the OA and runs through hills separating Santa Clara County from Santa Cruz County. The primary seismic hazard for the OA is potential ground shaking from these three large faults.52F 53 The Greenville fault in the
northeastern portion of the county presents less risk than these three major faults. Figure 22 provides 53 Association of Bay Area Governments. (n.d.). Earthquake. https://abag.ca.gov/our-work/resilience/dataresearch/earthquake

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location and probability of area fault lines. The three major faults are described further in the following sections.

Hayward Fault
The Hayward Fault runs parallel to and east of the San Andreas Fault. It extends from San José about 74 miles northward along the base of the East Bay Hills to San Pablo Bay. The fault is a right-lateral slip fault. The Hayward Fault extends through some of the Bay Area’s most populated areas. Communities on or near the fault include San José, Oakland, Fremont, Richmond, Berkeley, Hayward, San Leandro, San Lorenzo, El Cerrito, Emeryville, Kensington, and Milpitas. Among other sites, the fault runs directly under the now-abandoned old city hall in downtown Hayward, the University of California-Berkeley football stadium, the Mira Vista Golf Course near Berkeley, Lake Temescal, Contra Costa College, and Port Pinole Shoreline Regional Park. It is the single most urbanized earthquake fault in the United States.53F 54 The Hayward Fault is becoming a hazard priority throughout the Bay Area because of its increased chance for activity and its intersection with multiple highly populated areas and critical infrastructure.

According to the Uniform California Earthquake Rupture Forecast, Volume 3, released in March 2015, the probability of experiencing a Magnitude 6.7 or greater earthquake along the Hayward Fault in the next 30 years (starting from 2014) is 14.3 percent.54 F
55 An earthquake of this magnitude has regional implications for the entire Bay Area, as the Hayward Fault crosses transportation and resource infrastructure, including multiple highways, regional gas and water pipelines, electrical transmission lines, and the Hetch-Hetchy Aqueduct. Disruption of the Hetch-Hetchy system has the potential to severely impair water service to the Santa Clara County OA.

An important difference between the Hayward and San Andreas faults is “aseismic creep.” The San Andreas Fault is locked in many places; much of its energy is released in the form of earthquakes.

However, creep occurs in spots along the Hayward Fault. The ground moves a few millimeters each year, pulling apart sidewalks, pipelines and other structures that sit astride the fault. At Memorial Stadium at the University of California Berkeley, which was built in 1923, creep has caused the two sides of the stadium to be offset more than a foot, requiring retrofitting with expansion joints. Creep accounts for a small part of the total motion that takes place on a fault over geologic time; earthquakes account for the rest.5F 56 54 California Office of Emergency Services. (2016, July 6). Bay Area Earthquake Plan. https://www.caloes.ca.gov/wpcontent/uploads/Preparedness/Documents/BayAreaEQConopsPub_Version_2016.pdf. 55 U.S. Geological Survey. (2015, March). UCEFR3: A New Earthquake Forecast for California’s Complex Fault System. https://pubs.usgs.gov/fs/2015/3009/pdf/fs2015-3009.pdf 56 California Department of Conservation. (2008, October 7). Hayward Fault Fact Sheet. https://www.conservation.ca.gov/index/Pages/HaywardFaultFactSheet.aspx

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Figure 23: Significant Known Faults in the Bay Area56F
57 57 U.S. Geological Survey. (2016, August). Earthquake Outlook for the San Francisco Bay Region 2014-2043. https://pubs.usgs.gov/fs/2016/3020/fs20163020.pdf

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Calaveras Fault
The Calaveras Fault is a major branch of the San Andreas Fault, located to the east of the Hayward Fault. It extends 76 miles from the San Andreas Fault near Hollister to Danville at its northern end. The Calaveras Fault is one of the most geologically active and complex faults in the Bay Area. Recent research from the University of Berkeley suggests that the Hayward fault is essentially an offshoot of the Calaveras Fault.57F
58 This means that they could go off together, potentially creating a larger event as an earthquake’s magnitude is relative to its length. In a worst case scenario, a rupture along the Hayward fault could extend to the Calaveras Fault and south to where the Calaveras Fault meets the San Andreas Fault. The probability of experiencing a Magnitude 6.7 or greater earthquake along the Calaveras Fault in the next 30 years is 7.4% percent.

San Andreas Fault
The San Andreas Fault extends 810 miles from the East Pacific rise in the Gulf of California through the Mendocino fracture zone off the shore of northern California. The fault is estimated to be 28 million years old. The San Andreas Fault is an example of a transform boundary exposed on a continent. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip.

The San Andreas Fault is typically referenced in three segments. The southern segment extends from its origin at the East Pacific Rise to Parkfield, California, in Monterey County. The central segment extends from Parkfield to Hollister, California. The northern segment extends northwest from Hollister, through Santa Clara County, to its ultimate junction with the Mendocino fracture zone and the Cascadia subduction zone in the Pacific Ocean. The probability of experiencing a Magnitude 6.7 or greater earthquake along the San Andreas Fault within the next 30 years is 6.4 percent.

Maps of Earthquake Impact on the OA
The impact of an earthquake is largely a function of the following components:
 Surface fault rupture
 Ground shaking (ground motion accelerations)
 Liquefaction (soil instability)
Impacts vary with distance from the source (both horizontally and vertically). Mapping that shows the impacts of these components was used to assess the risk of earthquakes within the OA, as described in the sections below.

Probabilistic Seismic Hazard Map
A probabilistic seismic hazard map shows the hazard from earthquakes that geologists and seismologists agree could occur. The maps are expressed in terms of probability of exceeding a certain ground motion, such as the 10-percent probability of exceedance in 50 years. This level of ground shaking has been used for designing buildings in high seismic areas.58F
59 58 University of California Berkley. (2015, April 2). https://news.berkeley.edu/2015/04/02/calaveras-hayward-fault-linkmeans-potentially-larger-quakes/ 59 Probabilistic Seismic Hazard Assessment, Association of Bay Area Government Resilience Program (2018, February 22) https://www.arcgis.com/home/item.html?id=c3a21989363b484ca6f9c0730e14d9f6.

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Figure 24: 500-Year Probabilistic Earthquake Scenario Peak Ground Acceleration

7.2.3 ShakeMaps
A ShakeMap is a representation of ground shaking produced by an earthquake. The information it presents is different from the earthquake magnitude and epicenter that are released after an earthquake because ShakeMaps focus on the ground shaking resulting from the earthquake, rather than the parameters describing the earthquake source. An earthquake has only one magnitude and one epicenter, but it produces a range of ground shaking at sites throughout the region, depending on the distance from the earthquake, the rock and soil conditions at sites, and variations in the propagation of seismic waves from the earthquake due to complexities in the structure of the earth’s crust. A ShakeMap shows the extent and variation of ground shaking in a region immediately following significant earthquakes.

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Ground motion and intensity maps are derived from peak ground motion amplitudes recorded on seismic sensors (accelerometers), with interpolation based on estimated amplitudes where data are lacking, and site amplification corrections. Color-coded instrumental intensity maps are derived from empirical relations between peak ground motions and Modified Mercalli intensity.

There are two types of scenario ground motion maps: a ShakeMap of median shaking for a fault rupture; and a map of simulated ground motions for a specified earthquake hypocenter and fault rupture. The latter is more like an earthquake event and presents more variability in ground motions than a scenario ShakeMap.

Earthquake scenario maps describe the expected ground motions and effects of hypothetical large earthquakes for a region. The following scenarios were chosen for this plan:
• A Magnitude 7.0 on the Hayward Fault with an epicenter approximately 25 miles north of the City of Palo Alto. 59F
60 • A Magnitude 7.0 on the Calaveras Fault with an epicenter approximately 25 miles north of the City of Milpitas. 60F
61 • A Magnitude 7.8 on the San Andreas Fault with an epicenter approximately 148 miles northwest of the City of Palo Alto. 61F
62 60 U.S. Geological Survey Shakemap Scenario. (n.d.) M 7.0 Scenario Earthquake – Hayward – Rodgers Creek. https://earthquake.usgs.gov/scenarios/eventpage/nclegacyhaywardrodgerscreekhnhsm7p0_se/executive. 61 U.S. Geological Survey Shakemap Scenario (n.d.) M 7.0 Scenario Earthquake – Calaveras North + Central+ South. https://earthquake.usgs.gov/scenarios/eventpage/nclegacycalaverascncccsm7p0_se/executive. 62 USGS Shakemap Scenario (n.d.) M 7.8 Scenario Earthquake – N. San Andreas; North Coast + Peninsula + Santa Cruz Mountain.
https://earthquake.usgs.gov/scenarios/eventpage/nclegacynpsanandreassansapsasm7p8_se/executive.

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
Figure 25: Hayward Magnitude 7.0 Fault Scenario Peak Ground Acceleration

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Figure 26: Calaveras Magnitude 7.0 Fault Scenario Peak Ground Acceleration

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Figure 27: San Andreas Magnitude 7.8 Fault Scenario Peak Ground Acceleration Liquefaction Maps
Soil liquefaction maps are useful tools to assess potential damage from earthquakes. When the ground liquefies, sandy or silty materials saturated with water behave like a liquid, causing pipes to leak, roads and airport runways to buckle, and building foundations to be damaged. In general, areas with NEHRP Soils D, E, and F are also susceptible to liquefaction. If there is a dry soil crust, excess water will sometimes come to the surface through cracks in the confining layer, bringing liquefied sand with it, creating sand boils. Figure 27 shows the liquefaction susceptibility in the Santa Clara County OA.

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Figure 28: Liquefaction Susceptibility
Alquist-Priolo Zone Maps
The sliding movement of earth on either side of a fault is called fault rupture. Fault rupture begins below the ground surface at the earthquake hypocenter, typically between 3 and 12 miles below the ground surface in California. If an earthquake is large enough, the fault rupture will travel to the ground surface, potentially destroying structures built across its path.

California’s Alquist-Priolo Zone maps define regulatory zones for potential surface fault rupture where fault lines intersect with future development and populated areas. The purpose of these maps is to assist in the geologic investigation before construction begins to ensure that structures will not be located on an active fault.

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Cities and counties affected by the zones must regulate certain development projects while sellers of real estate must disclose at the time of sale that the property lies within such a zone. The Santa Clara County OA is located in a designated Alquist-Priolo Zone for the Hayward Fault.62 F 63 Alquist-Priolo maps were referenced, but not specifically used, in the assessment of risk for this plan. This plan assumes that the studies conducted and information provided by the State of California are the best available data for surface rupture risk and could not be improved through a separate assessment for this plan. Alquist-Priolo maps are available to the public on the California Department of Conservation website.63F
64 7.2.4 Frequency
California experiences hundreds of earthquakes each year, most with minimal damage and magnitudes below 3.0 on the Richter Scale. Earthquakes that cause moderate damage to structures occur several times a year. According to the USGS, a strong earthquake measuring greater than 5.0 on the Richter Scale occurs every 2 to 3 years and major earthquakes of more than 7.0 on the Richter Scale occur once a decade.

The USGS estimated in 2016 that there is a 72-percent probability of at least one earthquake before 2043 with a magnitude of 6.7 or greater that could cause widespread damage in the San Francisco Bay area.64F 65 According to the Third Uniform California Earthquake Rupture Forecast, the probability of moderate-sized earthquakes (magnitude 6.5 to 7.5) is lower than previously forecasted, whereas that of larger events is higher.65F
66 This is because the new study took into account the possibility of ruptures along multiple faults simultaneously. Probabilities for earthquakes on major fault lines in the San Francisco Bay Area have been estimated by the USGS in its 2016 report, as summarized in Table 21.

A major earthquake could happen at any time. Both the San Andreas and the Hayward Faults have the potential for experiencing major to great events. Large earthquakes along the Hayward Fault have occurred on average every 150 years – the last being in 1868.6F 67 USGS describe the fault as a “tectonic
time bomb.”.67F
68 Any seismic activity of 6.0 or greater on faults within the OA would have significant impacts throughout the OA. Bay Area communities can use the likelihood of a 6.8-7.0 earthquake near San Francisco as a predictive model of what to prepare for.

Further information on the impact of climate change on the probability of earthquakes is included in Section 11.

Probability in OA: Likely
63 California Department of Conservation. (2008). Hayward Fault Fact Sheet. https://www.conservation.ca.gov/index/Pages/HaywardFaultFactSheet.aspx 64 California Department of Conservation. (2023). The California Seismic Hazards Program. https://www.conservation.ca.gov/cgs/sh
65 U.S. Geological Survey. (2016, August). Earthquake Outlook for the San Francisco Bay Region 2014-2043. https://pubs.usgs.gov/fs/2016/3020/fs20163020.pdf
66 Southern California Earthquake Center. (2017). Third Uniform California Earthquake Rupture Forecast. https://www.scec.org/ucerf#:~:text=UCERF3%20shows%20the%20likelihood%20of%20moderatesized%20earthquakes%20%28magnitude,may%20occasional%20rupture%20together%20to%20cause%20larger%2 0earthquakes.
67 California Earthquake Authority. (2020, July 8). What to Expect from an Earthquake along the Hayward Fault. https://www.earthquakeauthority.com/Blog/2019/hayward-fault-earthquake-prediction 68 U.S. Geological Survey. (2008). The Hayward Fault – Is it Due for a Repeat of the Powerful 1868 Earthquake? https://pubs.usgs.gov/fs/2008/3019/

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Table 21: Earthquake Probabilities for the San Francisco Bay Area Region, 2014–204368F 69 Fault Probability of One or More M ≥ 6.7 Quake
2014–2043
Hunting Creek 16%
Green Valley 16%
Concord 16%
Greenville 16%
Berryessa 16%
Calaveras 26%
Maacama 8%
Rodgers Creek Fault 33%
Hayward 33%
San Andreas 22%
San Gregorio 6%

7.2.5 Severity
The severity of an earthquake can be expressed in terms of intensity or magnitude:
 Intensity represents the observed effects of ground shaking at any specified location. The intensity of earthquake shaking lessens with distance from the earthquake epicenter. Tabulated peak ground accelerations for listed “maximum credible earthquakes” are a measure of how a site will be affected by seismic events on distant faults.  Magnitude represents the amount of seismic energy released at the hypocenter of the earthquake. It is based on the amplitude of the earthquake waves recorded on instruments.

Magnitude is thus represented by a single, instrumentally determined value. 69 U.S. Geological Survey. (2017). Map of Known Active Faults and Earthquake Probabilities. https://www.usgs.gov/media/images/map-known-active-faults-and-earthquake-probabilities

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Figure 29: Peak Ground Acceleration with 10-percent Probability of Exceedance in 50 Years ABAG estimates a potential loss of 159,000 housing units in Bay Area communities after a large earthquake. This loss would have disastrous effects on local and regional economies. Recovery, repair, and rebuilding time for each household would be lengthy because of the number of homes that would need repair or replacement.

Annual losses also represent a sizable economic burden on the OA. According to FEMA 2023 report Hazus Estimated Annualized Earthquake Losses for the United States, the annualized earthquake loss ratio (AELR)—or the estimated building loss value as a fraction of the building inventory replacement value—for the San José metro area is the second highest in California69F

70. The metro areas include San
José, Sunnyvale, and Santa Clara. This finding emphasizes the fact that the severity of more frequent, non-catastrophic earthquakes is still significant enough to warrant further seismic risk reduction actions.

7.2.6 Warning Time
There is no current reliable way to predict when an earthquake will occur at any given location. Research and beta testing are being done with warning systems that use telecommunications that can travel faster than an earthquake’s high energy waves, called S waves. 70 FEMA. (April 2023). Hazus Estimated Annualized Earthquake Losses for the United States. Hazus Estimated Annualized earthquake losses for the United States, FEMA P-366

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The warning is generated by a rupture at an earthquake’s hypocenter and telecommunicated to provide a warning for shaking before the S waves arrive. These potential earthquake early warning systems could give up to approximately 40 seconds’ notice of peak earthquake shaking. In 2019, California became the nation’s first state to have a statewide earthquake early warning system. Early Warning California is able to provide alerts to the public seconds before an earthquake is felt. The warning time is very short, but it could allow for someone to get under a desk, step away from a hazardous material, or shut down a computer system.

7.3 Cascading Impacts
Earthquakes can cause a variety of cascading hazards including landslides, tsunamis, fires, dam failures, and hazardous material releases. Earthquakes cause large and sometimes disastrous landslides and mudslides. River valleys are vulnerable to slope failure, often as a result of loss of cohesion in clay-rich soils. Soil liquefaction occurs when water-saturated sands, silts, or gravelly soils are shaken so violently that the individual grains lose contact with one another and “float” freely in the water, turning the ground into a pudding-like liquid. Building and road foundations lose load-bearing strength and may sink quicksand-like into what was previously solid ground. Unless properly secured, hazardous materials can be released, causing considerable damage to the environment and people.

Depending on the location, earthquakes can also trigger tsunamis. Most tsunamis are caused by underwater earthquakes. The tsunami hazard is furthered described in Section 13. Earthen dams and levees are highly susceptible to seismic events, and the impacts of their eventual failures can be considered secondary risk exposure to earthquakes. Dams do not have to be destroyed in an earthquake for there to be devastating consequences. Dams can be cracked due to embankment deformation induced by ground shaking, experience foundation damage, or be impacted by an earthquake-cased landslide. Dam failures can result in significant downstream flooding. This hazard is further described in Section 12.

Additionally, fires can result from gas lines or power lines that are broken or downed during the earthquake. It may be difficult to control a fire, particularly if the water lines feeding fire hydrants are also broken. After the 1906 earthquake in San Francisco, for example, a fire burned for three days, destroying much of the city and leaving 200,000 people houseless.70F 71 Fires in urban areas present unique firefighting
and public health challenges. They would be a considerable concern after a major earthquake event.

7.4 Exposure

7.4.1 Population
The entire population of the OA is potentially exposed to direct and indirect impacts from earthquakes.

The degree of exposure is dependent on many factors, including the age and construction type of the structures people live in, the soil their homes are constructed on, their proximity to fault location, etc.

Whether directly impacted or indirectly impact, the entire population will have to deal with the consequences of earthquakes to some degree. Business interruption could keep people from working, road closures could isolate populations, and loss of functions of utilities could impact populations that suffered no direct damage from an event itself.
71 The U.S. National Archives and Records Administration. (n.d.). San Francisco Earthquake, 1906. https://www.archives.gov/legislative/features/sf#:~:text=On%20the%20morning%20of%20April%2018%2C%201906 %2C%20a,three%20days%20and%20destroyed%20nearly%20500%20city%20blocks..

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7.4.2 Property
According to Santa Clara County Tax Assessor records, there are 535,391 buildings in the OA, with a total replacement value of $381 billion. Since all structures in the OA are susceptible to earthquake impacts to varying degrees, this total represents the property exposure to seismic events. Table 22 shows the exposure value breakdown by jurisdiction with the OA.

Table 22: Earthquake Exposure by Jurisdiction
Jurisdiction Number of Buildings Total Building Value:

Structure and Contents
Campbell 14,494 $9,337,059,000
Cupertino 17,460 $14,466,910,000
Gilroy 11,597 $7,140,035,000
Los Altos 13,433 $9,697,438,000
Los Altos Hills 3,342 $4,077,127,000
Los Gatos 10,467 $7,634,327,000
Milpitas 20,912 $13,830,811,000
Monte Sereno 1,078 $986,431,000
Morgan Hill 21,044 $5,547,035,000
Mountain View 6,545 $14,501,750,000
Palo Alto 19,914 $16,233,190,000
San José 25,5703 $168,553,959,000
Santa Clara (city) 32,978 $26,584,014,000
Saratoga 10,214 $8,348,159,000
Sunnyvale 41,941 $28,567,428,000
Unincorporated County 54,269 $46,077,151,000
Total 535,391 $381,582,824,000

7.4.3 Loss Potential
Property losses were estimated through the Level 2 Hazus analysis for the 100-year and 500-year earthquakes and the three scenario events. Table 23 through Table 27 show the results for two types of property loss:
 Structural loss, representing damage to building structures.  Contents loss, representing the value of lost contents and inventory.  Total loss, representing a combination of direct (structural and content) and indirect costs such as relocation, income loss, rental loss, and wage loss.

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Table 23: Loss Estimates for 100-Year Probabilistic Earthquake Jurisdiction
Estimated Loss Associated with Earthquake
% of Total
Replacement
Value
Structure Contents Total
Campbell $83,411,720 $147,383,480 $714,842,110 6.42
Cupertino $110,113,070 $202,728,570 $944,296,790 5.58
Gilroy $111,762,750 $186,420,740 $919,308,810 10.87
Los Altos $60,407,350 $105,705,000 $516,809,420 4.75
Los Altos Hills $15,337,870 $32,413,630 $143,905,510 3.27 Los Gatos $52,214,200 $97,964,100 $469,109,470 5.21
Milpitas $229,633,340 $366,547,460 $1,792,104,770 10.79 Monte Sereno $5,582,230 $9,912,830 $48,082,010 4.59
Morgan Hill $85,693,050 $144,753,610 $647,026,030 9.86
Mountain View $138,215,630 $228,950,290 $1,135,921,470 6.55 Palo Alto $123,276,450 $234,519,070 $1,143,458,680 5.89 San José $2,271,729,230 $3,804,754,590 $18,548,766,290 9.19 Santa Clara (city) $371,540,110 $623,137,970 $2,922,510,780 9.07 Saratoga $46,922,910 $87,663,150 $411,758,710 4.52
Sunnyvale $277,402,330 $471,198,590 $2,271,326,290 6.81 Unincorporated
County
$491,709,760 $847,476,000 $4,002,857,370 7.40
Total $4,474,952,000 $7,597,529,080 $36,632,084,510 8.07 Table 24: Loss Estimates for 500-Year Probabilistic Earthquake Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Campbell $332,939,800 $514,222,930 $2,637,075,050 23.67 Cupertino $483,321,680 $773,618,650 $3,846,779,640 22.62 Gilroy $325,070,990 $496,300,090 $2,565,057,320 30.59
Los Altos $253,325,050 $368,045,620 $1,957,493,570 17.73 Los Altos Hills $79,356,360 $139,360,770 $675,309,730 14.98 Los Gatos $237,262,800 $375,686,540 $1,937,596,360 21.33 Milpitas $868,837,200 $1,284,918,220 $6,491,226,210 39.92 Monte Sereno $24,465,000 $32,498,890 $181,964,270 17.12 Morgan Hill $278,620,680 $446,000,140 $2,045,968,380 31.44 Mountain View $554,403,710 $860,895,660 $4,359,290,900 25.19

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Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Palo Alto $508,699,590 $904,493,750 $4,518,057,520 23.11 San José $7,547,645,640 $12,175,341,680 $60,078,192,300 30.15 Santa Clara (city) $1,281,702,680 $2,143,040,010 $10,023,437,510 31.60 Saratoga $215,118,140 $317,501,240 $1,672,277,590 18.05 Sunnyvale $1,022,240,280 $1,620,535,330 $8,017,810,470 24.07 Unincorporated County $1,834,740,210 $2,763,641,700 $13,914,201,350 25.85 Total $15,847,749,810 $25,216,101,220 $142,921,738,170 27.77 Table 25: Loss Estimates for San Andreas Fault Scenario Earthquake Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Campbell $49,214,560 $92,236,240 $432,374,280 3.91
Cupertino $81,301,810 $153,677,230 $710,419,020 4.24
Gilroy $33,481,560 $61,301,010 $280,483,670 3.24
Los Altos $55,804,220 $90,175,700 $462,202,090 4.27
Los Altos Hills $10,926,300 $20,917,530 $97,960,120 2.25 Los Gatos $27,424,860 $45,440,870 $234,302,660 2.58
Milpitas $296,969,340 $464,378,390 $2,282,091,580 13.76 Monte Sereno $2,727,410 $4,081,180 $21,982,080 2.10
Morgan Hill $24,995,170 $42,475,860 $184,472,540 2.78
Mountain View $132,855,600 $217,121,870 $1,083,896,690 6.22 Palo Alto $97,695,850 $200,178,300 $936,127,860 4.90
San José $1,868,771,120 $3,118,303,370 $14,933,844,800 7.34 Santa Clara (city) $325,662,720 $591,625,640 $2,655,220,690 8.28 Saratoga $27,814,510 $48,360,240 $237,674,840 2.62
Sunnyvale $260,122,500 $429,175,020 $2,076,576,830 6.17 Unincorporated County $288,238,330 $481,595,870 $2,294,416,020 4.20 Total $3,584,005,860 $6,061,044,320 $28,924,045,770 6.34 Table 26: Loss Estimates for Hayward Fault Scenario Earthquake Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Campbell $40,301,090 $98,620,250 $409,079,960 3.76

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Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Cupertino $76,928,120 $182,120,770 $752,020,960 4.56
Gilroy $30,147,280 $73,497,000 $305,747,590 3.72
Los Altos $45,091,440 $101,276,690 $433,600,270 4.03
Los Altos Hills $25,102,370 $58,726,440 $246,663,700 5.56 Los Gatos $49,681,050 $105,154,360 $470,871,870 5.23
Milpitas $22,068,720 $68,614,250 $254,995,140 1.61
Monte Sereno $4,912,510 $10,456,710 $45,981,960 4.41
Morgan Hill $17,740,240 $47,816,600 $177,511,110 2.78
Mountain View $65,744,520 $161,424,770 $669,374,410 3.94 Palo Alto $74,475,780 $202,860,830 $827,014,160 4.32
San José $412,039,580 $1,243,445,510 $4,732,726,140 2.46 Santa Clara (city) $78,077,550 $242,884,660 $886,193,970 2.89 Saratoga $48,918,390 $105,223,740 $456,057,380 5.04
Sunnyvale $97,943,980 $261,626,210 $1,041,138,290 3.22
Unincorporated
County
$206,686,640 $460,193,440 $1,944,849,460 3.66
Total $1,295,859,260 $3,423,942,230 $13,653,826,370 3.13 Table 27: Loss Estimates for Calaveras Fault Scenario Earthquake Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Campbell $40,939,680 $86,487,180 $386,261,760 3.56
Cupertino $71,012,520 $146,392,880 $651,211,640 3.95
Gilroy $19,238,740 $45,359,670 $188,770,670 2.26
Los Altos $50,620,630 $86,562,830 $431,369,830 4.03
Los Altos Hills $10,762,060 $20,780,700 $96,841,280 2.23 Los Gatos $23,993,340 $43,003,930 $213,109,080 2.40
Milpitas $209,898,010 $374,708,150 $1,728,857,450 10.54 Monte Sereno $2,665,370 $4,043,610 $21,636,660 2.08
Morgan Hill $15,897,370 $34,459,240 $137,948,090 2.14
Mountain View $105,347,590 $194,639,980 $921,924,650 5.39 Palo Alto $84,410,530 $188,043,650 $842,872,700 4.49
San José $1,354,935,210 $2,533,808,530 $11,560,267,970 5.78 Santa Clara (city) $250,185,320 $521,829,550 $2,208,182,000 6.99 Saratoga $26,733,350 $47,643,880 $231,358,470 2.57

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Jurisdiction
Estimated Loss Associated with Earthquake % of Total
Replacement
Structure Contents Total Value
Sunnyvale $198,860,640 $368,380,050 $1,711,126,870 5.17 Unincorporated
County
$211,495,100 $406,336,080 $1,828,500,120 3.42
Total $2,676,995,460 $5,102,479,910 $23,160,239,240 5.16 A summary of the property-related loss results is as follows:
 For a 100-year probabilistic earthquake shaking, the estimated damage potential is $36.6 billion, or 8 percent of the total replacement value for the OA.  For a 500-year probabilistic earthquake shaking, the estimated damage potential is $142.9 billion, or 27.8 percent of the total replacement value for the OA.  For a 7.8-magnitude event on the San Andreas Fault, the estimated damage potential is $28.9 billion, or 6.3 percent of the total replacement value for the OA.  For a 7.0-magnitude event on the Hayward Fault, the estimated damage potential is $13.7 billion or 5 percent of the total replacement value for the OA.  For a 7.0-magnitude event on the Calaveras Fault, the estimated damage potential is $23.2 billion, or 5.6 percent of the total replacement value for the OA.

The Hazus analysis also estimated the amount of earthquake-caused debris in the OA for the 100-year and 500-year earthquakes and the three scenario events, as summarized in Table 28: .

Table 28: Estimated Earthquake-Caused Debris
Scenario Debris to Be Removed (Thousands of Tons)
100-Year Earthquake 4,589
500-Year Earthquake 17,862
San Andreas Fault Scenario 3,902
Hayward Fault Scenario 1,106
Calaveras Fault Scenario 2,638

7.4.4 Critical Facilities and Infrastructure
All critical facilities in the OA are exposed to the earthquake hazard. Table 29: Number of Critical Facilities Exposed to Earthquakes lists the number of each type of facility by jurisdiction. Additionally, communities in the Bay Area are serviced by infrastructure that is susceptible to damage from earthquakes, as nearly all the infrastructure connection that the area depends on for water, electric power, fuel, and transportation services cross a fault.71F 72 Hazardous materials releases can occur during an
earthquake from fixed facilities or transportation-related incidents. Transportation corridors can be disrupted during an earthquake, leading to the release of materials to the surrounding environment. 72 California Office of Emergency Services. (2016, July 6). Bay Area Earthquake Plan. https://www.caloes.ca.gov/wpcontent/uploads/Preparedness/Documents/BayAreaEQConopsPub_Version_2016.pdf

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Facilities holding hazardous materials are of particular concern because of possible isolation of neighborhoods surrounding them. During an earthquake, structures storing these materials could rupture and leak into the surrounding area or an adjacent waterway, having a disastrous effect on the environment, or emit chemicals in a toxic plume.

Table 29: Number of Critical Facilities Exposed to Earthquakes Jurisdiction
Number of Facilities by Jurisdiction
Critical
Facilities Transportation Utilities Community Assets
Hazardous
Materials Total
Campbell 21 23 0 7 6 57
Cupertino 26 26 2 16 5 75
Gilroy 25 34 2 13 7 81
Los Altos 22 8 0 11 0 41
Los Altos Hills 6 21 0 2 0 29
Los Gatos 20 35 0 6 1 62
Milpitas 32 66 1 19 60 178
Monte Sereno 1 1 0 1 0 3
Morgan Hill 22 14 1 10 8 55
Mountain View 37 52 1 29 20 139
Palo Alto 49 42 4 46 26 167
San José 370 498 18 191 135 1,212
Santa Clara (city) 53 63 9 36 103 264
Saratoga 18 32 0 11 0 61
Sunnyvale 40 49 3 27 51 170
Unincorporated
County
35 187 17 48 4 291
Total 777 1151 58 473 426 2885

7.4.5 Environment
The entire OA is a seismically active area and could be exposed to ground shaking from several different faults. According to the Alquist-Priolo Earthquake Fault Zones map for the San Francisco Bay Region, all of the OA is likely to experience very strong, severe, or violent shaking. Environmental problems as a result of an earthquake could occur anywhere in the OA. Cascading hazards will likely have some of the most damaging effects on the environment.

7.5 Vulnerability
Earthquake vulnerability data was generated using a Level 2 Hazus analysis. Once the location and size of a hypothetical earthquake are identified, Hazus estimates the intensity of the ground shaking, the number of buildings damaged, the number of casualties, the damage to transportation systems and utilities, the number of people displaced from their homes, and the estimated cost of repair and cleanup.

Changes in conditions: No change in vulnerability

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• Overall, the OA is in a seismically active area with multiple fault sources. • The OA has a significant population and number of assets exposed to damage from earthquake which constitutes a high risk.
• Population and building development has grown but at a very slow rate and new buildings are built in accordance with seismic codes.

7.5.1 Population
Impacts on persons and households in the OA were estimated for the 100-year and 500-year shaking from earthquakes and the three scenario events through the Level 2 Hazus analysis. One of the primary impacts on population is being displaced from their homes and seeking alternative shelter. Table 30:

Estimated Earthquake Impact on Persons summarizes the results. People can also experience physical injury or death, be impacted by disruptions to transportation and utility systems, loss or wages or other loss of services from business interruptions.

There are estimated to be 29,329 people in 10,010 households living on soils with high to very high liquefaction potential in the OA, or about 1.52 percent of the total population. Higher liquefaction potential contributes to structural damage and subsequent displacement of people from their residences.

A summary analysis of demographics using the Hazus data identified populations with additional factors that add to their vulnerability to earthquake hazard. The Hazus model does not provide results for how specific demographic categories will be impacted by the different earthquake scenarios. This only provides a general indication of the number of people who may have a more difficult time recovering from the impacts of an earthquake.
 Economically Disadvantaged Populations: It is estimated that 2.45 percent of the people within the OA are economically disadvantaged, defined as having household incomes of $20,000 or less.
 Population over 64 Years Old: It is estimated that 260,705 persons or 13.5 percent of the population in the OA are over 64 years old.
 Population under 16 Years Old: It is estimated that 422,719 persons or 21.8 percent of the population within the OA under 18 years of age.
 Racial and ethnic minorities comprise a significant proportion of the population: 39% are Asian and 25% are Hispanic.

Table 30: Estimated Earthquake Impact on Persons
Scenario Number of Displaced
Households
Number of Persons Requiring
Short-Term Shelter
100-Year Shaking from Earthquakes 16,071 8,076
500-Year Shaking from Earthquakes 77,037 38,242
San Andreas ShakeMap Scenario 4,364 2,047
Calaveras ShakeMap Scenario 8,199 4,047
Hayward ShakeMap Scenario 2,708 1,282
The 100-year shaking results are less than the 500-year shaking results because stronger shaking occurs less often and is more likely to occur in a 500-year period than a 100-year period.

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7.5.2 Property
Building Age
Table 31 identifies significant milestones in building and seismic code requirements that directly affect the structural integrity of development. Using these time periods, the Core Planning Group used the National Structure Inventory to identify the number of structures in the OA by date of construction. The NSI provided limited data on the number of structures built between 2005 and 2016.

Table 31: Age of Structures in Operational Area
Time Period
Number of Current
OA Structures
Built in Period
Significance of Time Frame
1939-1940 7,853 In 1940, the first strong motion recording was made. 1941-1960 96,753 In 1960, the Structural Engineers Association of California published guidelines on recommended earthquake provisions. 1961-1975 224,356 In 1975, significant improvements were made to lateral force requirements.
1976–1993 141,510 In 1994, the Uniform Building Code was amended to include provisions for seismic safety.
1994–present 65,144 Seismic code is currently enforced. Please note that data on more recent structures are limited.

Total 535,616
The number of structures does not reflect the number of total housing units, as many multi-family units and attached housing units are reported as one structure.

Approximately 38.5 percent of the OA’s structures were constructed after the Uniform Building Code was amended in 1994 to include seismic safety provisions.

Soft-Story Buildings
A soft-story building is a multi-story building with one or more floors that are “soft” because of structural design. If a building has a floor that is 70-percent less stiff than the floor above it, it is considered a softstory building. This soft story creates a major weak point in an earthquake. Since soft stories are typically associated with retail spaces and parking garages, they are often on the lower stories of a building. When they collapse, they can take the whole building down with them, causing serious structural damage that may render the structure totally unusable.

These floors can be especially dangerous in earthquakes because they cannot cope with the lateral forces caused by the swaying of the building during a quake. As a result, the soft story may fail, causing what is known as a soft-story collapse. Soft-story collapse is one of the leading causes of earthquake damage to private residences.

Loss estimation and vulnerability analyses based on models with specified fragility curves for soft-story construction in the OA are not currently available to support quantitative analyses of risk. There are qualitative reports on risk available within the OA. These reports were not used for this analysis due to their lack of quantitative data. ABAG and other agencies in the Bay Area have programs generating this type of data, but it is not known when such data will be available for the Santa Clara County OA. This type of data will need to be generated to support future risk assessments of the earthquake hazard.

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Unreinforced Masonry Buildings
Unreinforced masonry buildings are constructed from materials such as adobe, brick, hollow clay tiles, or other masonry materials and do not contain an internal reinforcing structure, such as rebar in concrete or steel bracing for brick. Unreinforced masonry poses a significant danger during an earthquake because the mortar holding masonry together is typically not strong enough to withstand significant earthquakes.

Additionally, the brittle composition of these houses can break apart and fall away or buckle, potentially causing a complete collapse of the building.

In the Santa Clara County OA, unreinforced masonry buildings are generally brick buildings that were constructed before modern earthquake building codes and designs were enacted. The State of California enacted a law in 1986 that required all local governments in Seismic Zone 4 (nearest to active earthquake faults) to inventory unreinforced masonry buildings. The law encourages local governments to adopt local mandatory strengthening programs, delineate seismic retrofit standards, and put into place measures to reduce the number of people in unreinforced masonry buildings.

According to ABAG, housing units in unreinforced masonry buildings account for only 1-percent of the total Bay Area housing stock.72F
73 7.5.3 Critical Facilities and Infrastructure
Level of Damage
Hazus classifies the vulnerability of critical facilities to earthquake damage in five categories: no damage, slight damage, moderate damage, extensive damage, or complete damage. Hazus also classifies facilities in terms of loss-of-function and possible restoration times. The model was used to assign a vulnerability category to each critical facility category in the OA.

The analysis was performed for the 100-year and 500-year events and for all three fault scenarios.

Selected results are summarized in Table 32 through Table 37.

Table 32: Estimated Damage to Critical Facilities from 100-Year Earthquake Type of Critical Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Essential Facilities 777 151 0 257 N/A
Transportation 1154 12 0 1146 1154
Utilities 58 49 0 30 57
Community Assets 515 N/A N/A N/A N/A
Hazardous Materials 426 N/A N/A N/A N/A
Overall 2927 212 0 1433 1211
Notes: Damage level represents the highest-probability damage state for each facility. Values shown are accurate for comparison of results in this plan. See Section 6.7 for discussion of data limitations.

This scenario modeled significant impacts to essential facilities. Loss of functionality of these services will result in difficult response in the immediate aftermath of an earthquake. Furthermore, of the 656,063 73 Association of Bay Area Governments. (2016, March). Resilience Policy Guidance Document Soft Story Retrofit Program Development. https://abag.ca.gov/sites/default/files/soft_story_report_web_version_v2.pdf

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households, 203,485 are expected to be without potable water, and 358,285 without electric power on day one. Transportation systems will mostly remain functional.

Table 33: Essential Facility Functionality in 100-Year Probabilistic Earthquake Facility Total With >50% Functionality on
Day 1
Hospital 20 7
Schools 617 195
EOCs 7 4
Police Stations 35 12
Fire Stations 98 39
Table 34: Estimated Damage to Critical Facilities from 500-Year Earthquake Type of Critical
Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Essential Facilities 777 654 62 0 N/A
Transportation 1154 599 23 607 942
Utilities 58 58 14 0 31
Community Assets 515 N/A N/A N/A N/A
Hazardous Materials 426 N/A N/A N/A N/A
Overall 2957 1311 99 607 973
Notes: Damage level represents the highest-probability damage state for each facility. Values shown are accurate for comparison of results in this plan. See Section 6.7 for discussion of data limitations.

Table 35: Estimated Damage to Critical Facilities from Hayward Fault Type of Critical
Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Essential Facilities 777 25 0 704 N/A
Transportation 1154 0 0 1153 1154
Utilities 58 32 0 33 58
Community Assets 515 N/A N/A N/A N/A

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Type of Critical
Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Hazardous Materials 426 N/A N/A N/A N/A
Overall 2927 57 0 1890 1212
Notes: Damage level represents the highest-probability damage state for each facility. Values shown are accurate for comparison of results in this plan. See Section 6.7 for discussion of data limitations.

Table 36: Estimated Damage to Critical Facilities from San Andreas Fault Type of Critical
Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Essential Facilities 777 124 0 531 N/A
Transportation 1154 10 0 1151 1154
Utilities 58 29 0 33 58
Community Assets 515 N/A N/A N/A N/A
Hazardous Materials 426 N/A N/A N/A N/A
Overall 2927 163 0 1715 1212
Notes: Damage level represents the highest-probability damage state for each facility. Values shown are accurate for comparison of results in this plan. See Section 6.7 for discussion of data limitations.

Table 37: Estimated Damage to Critical Facilities from Calaveras Type of Critical
Facility Total
With
Moderate
Damage
With
Complete
Damage
With
Functionality
>50% on Day 1
With
Functionality
>50% on Day 7
Essential Facilities 777 45 0 579 N/A
Transportation 1154 10 0 1150 1154
Utilities 58 29 0 33 53
Community Assets 515 N/A N/A N/A N/A
Hazardous Materials 426 N/A N/A N/A N/A
Overall 2927 84 0 1762 1207
Notes: Damage level represents the highest-probability damage state for each facility. Values shown are accurate for comparison of results in this plan. See Section 6.7 for discussion of data limitations.

Hazardous Materials
An earthquake can cause hazardous material releases from fixed facilities and transportation-related releases. The Bay Area includes numerous oil refineries, chemical plants, tank farms, pipelines, high tech and biotechnology laboratories and production facilities and other industrial facilities.73F 74 74 California Office of Emergency Services. (2016, July 6). Bay Area Earthquake Plan. https://www.caloes.ca.gov/wpcontent/uploads/Preparedness/Documents/BayAreaEQConopsPub_Version_2016.pdf

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Additionally, there are there are multiple highways and railroads which transport HAZMAT, oil, and natural gas products in the OA. Although the Hazus scenarios did not include specific damage estimates for hazardous materials facilities, any facility could experience damage from severe ground shaking that could result in a HAZMAT incident.

Transportation
Liquefaction, landslides, and fault surface rupture during an earthquake can significantly damage roads.

Access to major roads is crucial to life and safety after a disaster event as well as to response and recovery operations. Disruptions in transportation systems are of particular concern in areas with limited access via transportation corridors, as a major event has the potential to isolate these communities from critical assistance and aid. Several communities in the OA extend into the foothills, where narrow and dead-end spur roads are common. Landslide susceptibility is also higher in these areas. Although the Hazus models did not indicate significant functional disruption to transportation network, past events indicate transportation damage should be expected that will disrupt response and recovery, and also require costly repairs.

Bridges
Earthquake shaking, liquefaction and landslides can significantly damage bridges, which often provide the only access to some neighborhoods. Since soft soil regions generally follow floodplain boundaries, those bridges that cross water courses are considered vulnerable. Key factors in the degree of vulnerability are the facility’s age and type of construction and soil classification at the bridge support structure, which indicate the standards to which the bridge was built. An example of the location of bridges in the OA with potential damage in the Calaveras Hazus Scenario is shown in Figure 29.

Figure 30: Highway Bridge Percentage Damage Exceeds Moderate: Calaveras Scenario Water and Sewer Infrastructure
Water and sewer infrastructure would likely suffer considerable damage in the event of an earthquake. If water and wastewater treatment plants were damaged, there could be a lack of potable water and spilling of raw sewage into bays or rivers.74F
75 Distribution systems with older brittle pipes are vulnerable to shaking 75 California Seismic Safety Commission. (1999). Earthquake Risk Management: A Toolkit for Decision-Makers. https://ssc.ca.gov/wp-content/uploads/sites/9/2020/08/ssc_1999-04_risk_toolkit.pdf

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and liquefaction in particular. Water and sewer restoration generally takes longer than other critical infrastructure. There would be significant regional needs for water after a Bay Area earthquake. Table 38 and Table 39 give more details on potential damage to these systems based on Hazus models. These indicate a significant number of residents across the OA without essential services for an extended time.

Table 38: Damage to Potable Water Systems by Hazus Scenario Potable Water Total Pipelines
Length
Number of
leaks
Number of
Breaks
Households
without service
at Day 7
100 Year 7,119 2,050 777 147,285
500 Year 7,119 13,762 4,974 625,830
San Andreas 7119 4,717 1,457 362,907
Calaveras 7119 4,696 1,375 342,397
Hayward 7,119 2,947 839 170,876
Table 39: Damage to Waste Water Systems by Hazus Scenario Waste Water Total Pipelines
Length
Number of
leaks
Number of
Breaks
100 Year 4,272 1,030 390
500 Year 4,272 6,913 2,498
San Andreas 4,272 2,369 733
Calaveras 4,272 2,359 691
Hayward 4,272 1,480 421

7.5.4 Environment
Environmental problems as a result of an earthquake can be numerous. Earthquakes can cause ground shaking, soil liquefaction, landslides, fissures, fires, dam failures, and tsunamis. Cascading hazards will likely have some of the most damaging effects on the environment. Earthquake-induced landslides in landslide-prone areas can significantly damage surrounding habitat. It is also possible for streams to be rerouted after an earthquake. Rerouting can change the water quality, possibly damaging habitat and feeding areas. There is a possibility that streams fed by groundwater wells will dry up because of changes in underlying geology. Hazardous material releases, including through transportation incidents, damage to sewers, and natural gas lines, as well as other infrastructure could seriously impact the environment.

7.5.5 Economic Impact
Earthquake events can severely disrupt the economy of the affected area. Economic impact will be largely associated with the disruption of power, gas, telecommunication, water, and wastewater services caused by an earthquake event. In general, major events may cause damage to land, buildings, transportation infrastructure, and businesses. With an event of such significance, economic recovery could take years, depending on available recovery funds.

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The total economic impact of a major earthquake is likely to spread well beyond the impacted area, especially in a population center like the Santa Clara County OA. This is often referred to the “ripple effect.”75F
76 The United States has a highly developed, specialized, interdependent, money economy. While those features make the economy productive and resilient, they also mean that a large magnitude earthquake will not be just a regional event. It has the potential to impact the national economy. An earthquake can result in impacts to the national economy including through disruptions to supply chains, shocks to financial markets, and drain on the insurance system.

Various sectors of the OA economy would be impacted differently. For example, tourism would likely be impacted over a long term while the impacted area recovers. The retail sector would likely recover quickly to support recovery, and the construction sector would eventually experience growth. Businesses would experience different levels of damage to property, loss of revenues, loss of market share and/or reputation. Business interruptions in recent California earthquakes have caused the failure of a number of small and medium-sized businesses.76F
77 Failed businesses impact the sales, property, and other tax revenue for local governments. Recovery of the economy is a key sign of a community’s resilience.

7.6 Future Trends in Development
Since all of the Santa Clara County Operational Area is located within an earthquake hazard zone, all future development will, to some extent, be exposed to the earthquake hazard. In the 30 years since the Loma Prieta earthquake, the bay region has invested about $80 billion (in 2016 U.S. dollars) in seismic strengthening of transportation, water, and other critical infrastructure; hospitals, schools, and governments facilities; and unreinforced masonry, soft story, and other types of buildings.7F 78 More work
needs to be done to prepare the region for the next major event. A key part of that is adopting and enforcing land use practices and building codes that consider seismic hazards.

Land use planning is directed by general plans adopted under California’s General Planning Law.

Municipal planning partners are encouraged to establish General Plans with policies directing land use and dealing with issues of geologic and seismic safety. These plans provide the capability at the local municipal level to protect future development from the impacts of earthquakes. All planning partners reviewed their general plans under the capability assessments performed for this effort. Deficiencies identified by these reviews can be identified as mitigation actions to increase the capability to deal with future trends in development.

Unincorporated Santa Clara County and the development departments in participating jurisdictions will strictly enforce all seismic building codes and design standards to prevent loss of life and property caused by earthquake. Public education, cooperation with the development community, and individual preparedness are essential as the OA welcomes thousands of new residents and hundreds of new businesses to each year. It will take a whole community approach to prepare for the next seismic event.

Kaiser Permanente, a health care organization, was highlighted by FEMA as a mitigation best practice for its work to seismically retrofit or replace its existing hospitals and buildings, including the Santa Clara Medical Center, in accordance with California Senate Bill 1953. ABAG’s Resilience Program assists Bay Area local governments and residents in planning and preparing for earthquakes through data, planning, policy, and implementation tools. Plan Bay Area 2050 proposes long-term strategies for minimizing damage from a major earthquake.
76 National Academies of Since, Engineering and Medicine. (1992). The Economic Consequences of a Catastrophic Earthquake. https://nap.nationalacademies.org/catalog/2027/the-economic-consequences-of-a-catastrophicearthquake-proceedings-of-a 77 California Seismic Safety Commission. (1999). Earthquake Risk Management: A Toolkit for Decision-Makers. https://ssc.ca.gov/wp-content/uploads/sites/9/2020/08/ssc_1999-04_risk_toolkit.pdf 78 U.S. Geological Survey. (2021, October). They HayWired Earthquake Scenario. https://pubs.usgs.gov/fs/2021/3054/fs20213054.pdf

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It aims to provide means-based financial support for the retrofit of existing residential buildings. These investments would ensure higher seismic standards to protect residents, especially those with lowincome, from earthquakes.

7.7 Scenario
With the abundance of fault exposure in the Bay Area, the potential scenarios for earthquake activity are many. An earthquake does not have to occur within the OA to have a significant impact on the people, property, and economy of the OA. In 2018, the USGS in partnership with the Southern California Earthquake Center shared hypothetical earthquake scenario known as the HayWired Earthquake Scenario which imagined a M7.0 earthquake centered in Oakland, California rupturing the Hayward fault along its length for about 52 miles. In this scenario, the entire OA would experience ground shaking and severe impacts. A screenshot from the computer simulation of the earthquake shows the region that would be impacted in Figure 30.

If this type of event were to occur, there would be significant impacts through the OA, region, and nation.

More than a million Bay Area homes would be impacted.78F 79 Potential warning systems would be able to
provide mere seconds or tens of seconds of warning time. This would not provide adequate time for preparation. There would be immediate need for first responder assistance. Many thousands of people could be stranded in elevators or under debris. Models predict hundreds of deaths and thousands of injuries. There would be massive structural failure of property on NEHRP C, D, E, and F soils. Levees and revetments built on these poor soils would likely fail, representing a loss of critical infrastructure. Fires could be started and, in worse case scenarios, turn into to firestorms, devastating urban areas. Electricity may not return for days. Water restoration may take up to a month. Many homes, particularly those built to older building code standards, would be considered unsafe to return to. Tens of thousands of households could be displaced. Aftershocks would continue to rock the area, causing more damage than the main shock in communities like Palo Alto.79F
80 Aftershocks would be felt for months to years after the earthquake event. Cascading impacts, like landslides and mudslides, could further damage structures.

River valley hydraulic-fill sediment areas are also vulnerable to slope failure, often as a result of loss of cohesion in clay-rich soils. Soil liquefaction would occur in water-saturated sands, silts, or gravelly soils.

The long-term impacts of an earthquake like this would be enormous. The estimated financial loss to residential, commercial, and infrastructure would be over $100 billion around the Bay Area. 79 California Earthquake Authority. (2020, July 8). What to Expect from an Earthquake along the Hayward Fault. https://www.earthquakeauthority.com/Blog/2019/hayward-fault-earthquake-prediction 80 U.S. Geological Survey. (2018). The HayWired Scenario: An Urban Earthquake in a Connected World. https://geonarrative.usgs.gov/haywired_vol1/#:~:text=The%20U.S.%20Geological%20Survey%20%28USGS%29%2 0HayWired%20scenario%20considers,fact%2C%20the%20HayWired%20earthquake%20will%20probably%20never %20occur.

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Figure 31: Hayward Fault Earthquake Scenario80F
81 7.8 Issues
Important issues associated with an earthquake include the following:
 More quantitative information is needed on the exposure and performance of soft-story construction within the OA.
 Approximately 29 percent of the OA’s building stock was built prior to 1975, when seismic provisions became uniformly applied through building code applications.  Based on the modeling of critical facility performance performed for this plan, a portion of facilities in the OA is expected to have complete or extensive damage from scenario events. These facilities are prime targets for structural retrofits.
 Critical facility owners should be encouraged to create or enhance continuity of operations plans using the information on risk and vulnerability contained in this plan.  Geotechnical standards should be established that consider the probable impacts from earthquakes in the design and construction of new or enhanced facilities.  There are a large number of high risk dams within the OA. Dam failure warning and evacuation plans and procedures should be reviewed and updated to reflect the dams’ risk potential associated with earthquake activity in the region.
81 U.S. Geological Survey. (2018, January 18). HayWired Scenario. https://www.usgs.gov/programs/scienceapplication-for-risk-reduction/science/haywiredscenario#:~:text=The%20HayWired%20earthquake%20scenario%20is%20a%20magnitude%207.0,Ma%20By%20Ea rthquake%20Hazards%20Program%20June%2016%2C%202020

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 Earthquakes could trigger other natural hazard events such as liquefaction, dam failures and landslides, and fire which could severely impact the OA.  A worst-case scenario would be the occurrence of a large seismic event during a flood or highwater event. Levee failures would happen at multiple locations, increasing the impacts of the individual events.
 Citizens are expected to be self-sufficient up to 3 days after a major earthquake without government response agencies, utilities, private-sector services, and infrastructure components.

Education programs are currently in place to facilitate development of individual, family, neighborhood, and business earthquake preparedness. Government alone can never make this region fully prepared. It takes individuals, families, and communities working in concert with one another to truly be prepared for disaster.
 After a major seismic event, the Santa Clara County Operational Area is likely to experience disruptions in the flow of goods and services resulting from the destruction of major transportation infrastructure across the broader region.
 The Santa Clara County OA is home to multiple tech centers that provide goods and services to the nation and world. A major earthquake in the region would disrupt these service providers and severely impact the economic and functional stability of the region and potentially the country.

Table 40: EMAP Consequence Analysis: Earthquake
Subject  Ranking  Impacts/Earthquake
Public  Minimal to
severe
Depending on the size and location of the earthquake, the public may be at significant risk from an earthquake event.

They could sustain injuries from falls, collapsing building, fall items, and damaged utilities, as well as any number of cascading impacts. Loss of life is possible. There could be significant disruption to normal life following an event.

People with disabilities and access/functional needs, as well as other diverse characteristics that may impact their ability to respond and recover from an event, will need additional assistance.

Responders  Minimal to
severe
First responders would be relied upon during the
aftermath of an earthquake and potentially exposed to
increased risk of injury and loss of life, particularly from aftershocks.

Continuity of
Operations (including
continue delivery of
services)
Minimal to
severe
Earthquakes can damage buildings, roads, utilities, and other critical infrastructure necessary for normal
operations. Government facilities may be impacted.

Records and systems may be damaged or destroyed.

Damages may take a long time to repair. Delivery of
services may be disrupted.

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Subject  Ranking  Impacts/Earthquake
Property, Facilities, and
Infrastructure
Minimal to
severe
Depending on the location and magnitude of the
earthquake, buildings be damaged or destroyed; bridges, highways, dams, and other public infrastructure may fail; utilities would be interrupted; and community lifelines would be impacted. There would be debris to clean-up.

There may be additional cascading impacts, like
landslides, tsunamis, fires, or dam failures which
compound the event. Medical facilities, mass-care
shelters, and essential food and water supply chains
would be critical to quickly restore post-event.

Environment  Minimal to
severe
Earthquake-caused cascading impacts could negatively
impact the environment. Landslides, tsunamis, fires, and dam failures can occur after an earthquake. Disruption to waterways, such as through rerouting streams and debris, could possibly damage habitat and feeding areas.

Hazardous materials release would be a serious concern.

Economic Conditions  Minimal to
severe
Impacts to the economy will largely depend on the amount of damage and destruction to facilities, infrastructure, and transportation lifelines. Major damage or significant delays in recovery could severely impact the local, state, national, and even global economy.

Public Confidence in
the Government
Minimal to
severe
The public’s confidence in the government will depend on how it handles response and recovery efforts to the event.

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8 Wildfire
Definitions
 Interface Area: An area susceptible to wildfires and where wildland vegetation and urban or suburban development occur together. An example would be smaller urban areas and dispersed rural housing in forested areas.
 Wildfire: Fires that result in uncontrolled destruction of forests, brush, field crops, grasslands, and real and personal property in non-urban areas. Because of their distance from firefighting resources, they can be difficult to contain and can cause a great deal of destruction.

8.1 General Background
A wildfire is any uncontrolled fire occurring on undeveloped land that requires fire suppression. Wildfires can be ignited by lightning or by human activity such as smoking, campfires, equipment use, sparks from power lines, and arson.

Fire hazards present a considerable risk to vegetation and wildlife habitats. Short-term loss caused by a wildfire can include the destruction of timber, wildlife habitat, scenic vistas, and watersheds. Long-term effects include smaller timber harvests, reduced access to affected recreational areas, and destruction of cultural and economic resources and community infrastructure. The potential for significant damage to life and property exists in areas designated as “wildland urban interface areas,” where development is adjacent to densely vegetated areas.

There are a few different types of wildfires:
 Ground Fires: Fires that burn when surface fuels, such as organic soils, duff, decomposing litter, buried logs, roots, and the below-surface portion of stumps ignite and burn under the ground.

Ground fires may eventually burn through the ground surface and become surface fires.  Surface Fires: Fires that burn on the surface of the ground and are primarily fueled by low-lying vegetation such as leaf and needle litter, dead branch material, downed logs, bark, trees bones, and low statute living plants.
 Ladder Fuels: Dead or live vegetation such as low-lying tree branches, shrubs, and trees under the tree canopy that allows an active fire to spread from the forest floor into the tree canopy to become crown fires.
 Crown Fires: Fires that spread from treetop to treetop, typically at a rapid pace. They are often pushed by wind and can become extremely intense and difficult to put out.  Spotting Fires: Fires that involve burning embers which are thrown ahead of the main fire. This type of fire can be produced by crown fires depending on wind and topography. Once they begin, spotting fires are difficult to control.

The Santa Clara County Community Wildfire Protection Plan was used to inform parts of this risk assessment and can be accessed for an in-depth look at the County’s wildfire risk and other supporting data. The plan can be found online with the following link:
https://www.sccfd.org/santa-clara-county-community-wildfire-protection-plan/

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8.2 Hazard Profile

8.2.1 Past Events
Wildfire poses a significant risk to public health and safety, economies, infrastructure, and irreplaceable cultural and natural resources within the OA.81F
82 Wildfire is an annual risk in Santa Clara County.82F83 The following are wildfires of over 10 acres that have been recorded in or near the OA before February 2023.83F
84 Table 41: Past Wildfire Events
Event Name
Event Period
Additional Information
From To
Lexington Fire 6/26/1985 7/19/1985 FEMA-739-DR-CA. This federal wildfire disaster included six counties. In Santa Clara County, the worst of the fires affected the Santa Cruz Mountains south of the City of San José, threatening at least 2,000 homes
and forcing the evacuation of more than 4,500
people.84 F
85 Felter Fire 10/25/2006 10/26/2006 Burned 200 acres.

Stevens Fire 8/30/2007 9/2/2007 Burned 151 acres near Stevens Canyon Reservoir.

Lick Fire 9/3/2011 9/11/2007 Burned 47,760 acres at Henry Coe State Park, with four residences and 20 outbuildings destroyed.

Summit Fire 5/22/2008 5/30/2008 FEMA-2766-FM-CA. Burned 4,270 acres along with 35 residences, 64 outbuildings at Summit Road and
Maymen Flats, south of the Town of Loma Prieta.

Whitehurst/
Hummingbird
Fires
6/21/2008 6/26/2008 Burned 794 acres at Hummingbird and 200 acres at Whitehurst.

Pacheco Fire 8/29/2009 8/30/2009 Burned 1,650 acres.

Croy Fire 9/23/2002 10/5/2002 FM-2465. Burned 13,128 acres.

McDonald Fire 7/21/2011 7/21/2011 Burned 27 acres east of the City of Morgan Hill below Anderson Lake.

Uvas Fire 7/12/2013 7/12/2013 Burned 50 acres along Uvas Road and Casa Loma Road, near Calero County Park and west of the City of
Morgan Hill.

Grant Fire 12/31/2013 12/31/2013 Burned 40 acres off Mount Hamilton Road near Grant Ranch County Park.
82 Santa Clara County Fire Department. (2016, August). Santa Clara Community Wildfire Protection Plan. https://www.sccfd.org/santa-clara-county-community-wildfire-protection-plan/ 83 County of Santa Clara. (2012). Silicon Valley 2.0. https://sustainability.sccgov.org/silicon-valley-20 84 State of California. (2023). California Department of Forestry and Fire Protection. https://www.fire.ca.gov/ 85 Los Angeles Times. (1985, July 10). Fire Imperils 2,000 Homes Near San José. https://www.latimes.com/archives/la-xpm-1985-07-10-mn-7612-story.html

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Event Name
Event Period
Additional Information
From To
Curie Fire 6/30/2014 7/1/2014 Burned 125 acres off Curie Drive south of the City of San José.

Casa Fire 8/28/2014 8/31/2014 Burned 80 acres along Highway 152 at Casa De Fruta.

Highway Fire 6/30/2015 7/3/2015 Burned 42 acres off Highway 101 near Monterey Frontage Road, south of the City of Gilroy.

Pacheco Fire 9/9/2015 9/10/2015 Burned 215 acres off Highway 152 at Dinosaur Point, three miles west of San Luis Reservoir.

Sierra Fire 7/30/2016 7/31/2016 Burned 114 acres off Sierra Road and Calaveras Road.

Bailey Fire 8/17/2016 8/18/2016 Burned 100 acres off Highway 101 and Bailey Road.

Oak Fire 9/1/2016 9/2/2016 Burned 25 acres off Oak Glen Avenue, two miles west of the City of Morgan Hill.

Loma Fire 9/26/2016 10/12/2016 Burned 4,474 acres and destroyed 12 residences and 16 outbuildings off Loma Prieta Road and Loma
Chiquita Road, 10 miles northwest of the City of
Morgan Hill.

Quimby Fire 6/21/2017 6/21/2017 Burned 54 acres off Quimby Road, west of Great Ranch Park, East San José.

Ranch Fire 6/29/2017 6/29/2017 Burned 85 acres off Grant Road, Mt. Hamilton, east of the City of San José.

Felipe Fire 7/10/2017 7/10/2017 Burned 70 acres by San Felipe Road and Metcalf Road, 8 miles northeast of City of Morgan Hill.

Lariat Fire 7/11/2017 7/11/2017 Burned 101 acres along Lariat Lane and Claitor Way, six miles northeast of the City of San José.

Castro Fire 7/23/2017 7/23/2017 Burned 78 acres off Castro Valley Road & Highway 101, southwest of the City of Gilroy.

Weller Fire 7/26/2017 7/26/2017 Burned 51 acres along Weller Road and Calaveras Road, three miles east of the City of Milpitas.

Tilton Fire 8/11/2017 8/11/2017 Burned 100 acres by Hale Avenue and Tilton Avenue in the City of Morgan Hill.

Bally Fire 9/3/2017 9/3/2017 Burned 100 acres by Ballybunion Court in the City of Gilroy.

Keeler Fire 5/27/2018 5/27/2018 Burned 16 acres by Keeler Court and Santa Teresa Boulevard, south of the City of San José.

Tesla Fire 6/29/2018 6/29/2018 Burned 70 acres across Tesla Road and Reuss Road, east of the City of Livermore.

Bridle Fire 7/6/2018 7/6/2018 Burned 116 acres off Bridal Path Drive and Butch Drive, east of the City of Gilroy.

Curie Fire 7/10/2018 7/10/2018 Burned 70 acres by Curie Drive and San Ignacio Avenue, southwest of San José.

Hale Fire 7/10/2019 7/10/2019 Burned 51 acres at Hale Avenue and Monterey Street in the City of Morgan Hill.

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Event Name
Event Period
Additional Information
From To
Country Fire 7/22/2018 7/22/2018 Burned 320 acres along Country Club Road and North Park Victoria Road in the City of Milpitas.

Quimby Fire 9/23/2018 9/23/2018 Burned 30 acres by Quimby Road and Borden Drive, East San José.

Park Fire 10/7/2018 10/7/2018 Burned 62 acres along Monterey Road and Coyote Creek Golf Drive, north of the City of Morgan Hill.

Canyon Fire 5/30/2019 6/11/2019 Burned 144 acres off Del Puerto Canyon Road and Diablo Grande Parkway, west of the City of Patterson.

Malech Fire 6/9/2019 6/11/2019 Burned 210 acres by Malech Road & Bailey Road, South San José.

Calaveras Fire 6/10/2019 6/17/2019 Burned 35 acres by Calaveras Road and Weller Road east of the City of Milpitas.

Mines Fire 6/26/2019 6/27/2019 Burned 17 acres by Mines Road and Turner Gulch in the San Antonio Valley.

Coyote Fire 7/2/2019 7/2/2019 Burned 74 acres by Northbound US 101 at Coyote Creek Golf Drive in the City of San José.

Aborn Fire 7/15/2019 7/15/2019 Burned 47 acres off Aborn Road and Murillo Avenue, East San José.

Sweigert Fire 7/24/2019 7/24/2019 Burned 80 acres off Kahler Court and Felter Road, East of the City of Milpitas.

Bayliss Fire 8/15/2019 8/15/2019 Burned 60 acres by Santa Teresa Boulevard and Bayless Drive, South San José.

Jamieson Fire 8/25/2019 8/25/2019 Burned 35 acres at Jamieson Road and Cañada Road near the City of Gilroy.

Reservoir Fire 9/21/2019 9/24/2019 Burned 128 acres near Calaveras Road and Felter Road, 5 miles northeast of the City of Milpitas.

Point Fire 10/7/2019 10/7/2019 Burned 29 acres between Highway 152 and Dinosaur Point Road.

Santa Clara Unit
(SCU) Lightning
Complex Fire
8/16/2020 10/1/2020 Burned 396,624 acres between Santa Clara County, Alameda County, Contra Costa County, San Joaquin
County, Merced County, and Stanislaus County.

Silver Fire 6/4/2020 6/4/2020 Burned 19 acres by Dutch Flat Trail, East of the City of San José.

Colleen Fire 6/4/2020 6/7/2020 Burned 126 acres around Colleen Drive, South San José.

Park Fire 7/4/2020 7/6/2020 Burned 353 acres by East Dunne Avenue and Finley Ridge Road, east of the City of Morgan Hill.

Crews Fire 7/5/2020 7/13/2020 Burned 5,513 acres by Crews Road and Oak Spring Circle, north of the City of Gilroy.

Alum Fire 7/11/2020 7/11/2020 Burned 31 acres by Mt. Hamilton and Crothers Road, northeast of the City of San José.

Coyote Fire 8/21/2020 8/26/2020 Burned 143 acres by Monterey Road and Coyote Creek Golf Drive.

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Event Name
Event Period
Additional Information
From To
Silicon Valley
Fire
6/14/2021 6/14/2021 Burned 35 acres by off Silicon Valley Road and Basking Ridge, East San José.

Paseo Fire 6/25/2021 6/25/2021 Burned 37 acres by Paseo Robles Avenue and Paseo Vista Avenue, east of the City of Morgan Hill.

The 2020 fire season was the largest wildfire season recorded in California’s modern history. It was also the most devastating in recent Santa Clara County history. One fire significantly outpaced the rest. The SCU Lightning Complex fire started as a series of almost twenty fires on August 16, 2020, and burned until October 1, 2020, engulfing 396,624 acres five counties. At least 26 structures were damaged and 225 destroyed. There were 6 confirmed injuries to fire personnel and civilians and no deaths. As of this writing, it was the fourth largest fire in California’s recorded history.

8.2.2 Location
Wildfires occur in two distinct spaces: wildlands, and the Wildland Urban Interface (WUI). Wildland fires that burn in natural, undeveloped settings actually benefit the landscape through cleaning the forest floor from heavy brush, killing disease, providing food and habitat to forest animals and birds in the new vegetation that grows, and supporting new generations of plants that require intense heat for seed germination.

According to the U.S. Fire Administration,85F
86 the WUI is the zone of transition between occupied land and human development. It is the line, area, or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels. The WUI possess unique wildfire risks as fire can easily move between structural and vegetative fuels. The WUI has seen exponential growth in recent years. It is vital that WUI communities continue to work to address the WUI wildfire issue.

Figure 32: Air Tanker Dropping Fire Retardant on Lick Fire in Santa Clara County86F 87 Fire-prone areas in California are divided into three categories: federal responsibility areas, state responsibility areas, and local responsibility areas. The California Department of Forestry and Fire Protection (CAL FIRE) has responsibly for fire prevention and firefighting services within the state 86 U.S. Fire Administration. (2022). What is the WUI? https://www.usfa.fema.gov/wui/what-is-the-wui.html 87 Schulz, W. (n.d.). Air tanker dropping fire retardant on Lick Fire in Santa Clara County [Photograph]. California Department of Forestry and Fire Protection, California.

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responsibility areas, while local agencies have local responsibility areas, and the U.S. Forest Service has fire-related responsibilities in the federal responsibility areas.

CAL FIRE’s Fire and Resource Assessment Program has modeled and mapped fire hazard risk using a science-based and field-tested model that assigns a hazard score based on factors that influence fire likelihood and fire behavior such as fire history, existing and potential fuel (natural vegetation), predicted flame length, blowing embers, terrain, and typical fire weather for an area. These factors include the following:
 Fuel: Fuel may include living and dead vegetation on the ground, along the surface as brush and small trees, and above the ground in tree canopies. Lighter fuels such as grasses, leaves and needles quickly expel moisture and burn rapidly, while heavier fuels such as tree branches, logs and trunks take longer to warm and ignite. Trees killed or defoliated by forest insects and diseases are more susceptible to wildfire.
 Weather: Relevant weather conditions include temperature, relative humidity, wind speed and direction, cloud cover, precipitation amount and duration, and the stability of the atmosphere. Of particular importance for wildfire activity are wind and thunderstorms:
▪ Strong, dry winds produce extreme fire conditions. Such winds generally reach peak velocities during the night and early morning hours. It accounts for flying ember production, which is the principal driver of the wildfire hazard in densely developed areas. ▪ The thunderstorm season typically begins in June with wet storms and turns dry with little or no precipitation reaching the ground as the season progresses into July and August. Traditionally, this “fire season” between July and November would be when the State sees the most wildfires. However, according to the 2018 Strategic Fire Plan, climate change has rendered that term obsolete, as fires now burn year-round.  Terrain: Topography includes slope and elevation. The topography of a region influences the amount and moisture of fuel; the impact of weather conditions such as temperature and wind; potential barriers to fire spread, such as highways and lakes; and elevation and slope of landforms (fire spreads more easily uphill than downhill).  Probability of Future Occurrence: The likelihood of an area burning over a 30- to 50-year time period, based on history and other factors.

Fire Hazard Severity Zones (FHSZ) are ranked into the following risk classifications: moderate, high, or very high. The model covers the State Responsibility Area (SRA), which is the land where the State of California is financially responsible for the prevention and suppression of wildfires. It does not include lands within incorporated city boundaries or in federal ownership.

Significant land-use changes need to be accounted for through periodic model updates. The Wildfire Hazard Severity Zone Map87 F
88 was updated in 2007, and since updated in 2023 to reflect all that has happened in terms of scientific data, a changing climate, and other factors. The new model incorporates local climate data and changes in burn probability based on recent trends in fire occurrence. Overall, the map shows increase fire hazard, reflecting the State’s increase in wildfire occurrence and severity. It is important CAL FIRE continues to maintain these maps in order to build more resilient, fire-adapted communities. GIS data of the 2023 update was not yet released to include in the maps for this plan. The FHSZs shown throughout use the 2007 data.

Figure 32 shows the FHSZ mapping for the Santa Clara County OA. 88 State of California. (2023). Fire Hazard Severity Zones Map. https://osfm.fire.ca.gov/divisions/community-wildfirepreparedness-and-mitigation/wildfire-preparedness/fire-hazard-severity-zones/fire-hazard-severity-zones-map/

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Figure 33: Fire Hazard Severity Zones (FSHZ)
Typically, wildfires will occur anywhere in the County outside of the urbanized Highway 101 corridor and Santa Clara Valley. In general, the areas with the highest fire risk hazard are found in the parts of the OA farthest from urbanized areas, including along the border with Stanislaus and Santa Cruz Counties.

However, there are also Very High FHSZs near urban areas, including south of Los Gatos, west of Saratoga, west of Morgan Hill, and west of Gilroy.

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Wildfires are not also limited to Very High risk areas and can occur in Moderate or High FHSZs. The Santa Clara County General Plan8F
89 suggests much of Santa Clara County is at high risk to wildfires due to:
 Climatic factors, such as rainfall, humidity, and wind patterns;  Volume of naturally occurring fuel, such as brush, dead trees, and grasses that ignite easily and burn hotly;
 Steepness of slopes; and
 Inaccessibility and lack of available water supplies for fire suppression.

Additional information on wildfire hazard and risk to structures are available in the 2020 Santa Clara, Santa Cruz, San Mateo County Wildfire Risk to Structures and Classified Wildfire Hazard Maps.89F 90 The
classified wildfire hazard was calculated by 9 weighted input data sets that contribute to the potential for wildfire. These include fire environment factors such as fuel, weather, topography and ignition sources, the probability of a fire occurring at a specific point during a specific time period, and the expected distribution of intensity. This wildfire hazard model resulted in a 20-meter raster with 6 classes of relative wildfire hazards. Because this classified hazard data was of finer resolution and completed more recently, it was the primary source used to evaluate potential exposure and risk in the OA. 89 County of Santa Clara. (1994, December 20). General Plan. https://plandev.sccgov.org/ordinances-codes/generalplan 90 Santa Cruz Mountains Stewardship Network. (2020) Santa Clara, Santa Cruz, San Mateo County Wildfire Risk to Structures and Classified Wildfire Hazard Maps for Fire Prevention Planning.

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Figure 34: Classified Wildfire Hazard
 This hazard classification does not account for resources or assets exposed to the hazard.

Wildfire risk is the potential for adverse consequences to valued resources or assets. The Wildfire Risk to Structures map models risk by one value: structures. This map displays 10-acre hexagons ranked for wildfire hazard and structure density. Hexagons with high structure density and high wildfire hazard indicate areas of greatest concern.

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Figure 35: Wildfire Risk to Structures

8.2.3 Frequency
Wildfire frequency can be assessed through review of the portion of an area burned in previous wildfire events. Table 42 includes a summary of CAL FIRE records of fires from 1950 to 2021. About 39 percent of the mapped wildfire risk zones in the Santa Clara County OA have burned in that period.

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Table 42: Record of Fire Affecting Operational Area
Fire Hazard
Severity Zone
(FHSZ)
Total Area in
Wildfire Severity Zone
(acres)
Area Burned, 1950-2021
Acres Percent of Total
Moderate FHSZ 33,549 2,377 7.1
High FHSZ 372,517 119,693 32.1
Very High FHSZ 148,389 93,224 62.8
Total 554,455 215,295 38.8
The National Fire Plan directs funding to be provided for projects intended to reduce fire risks to a community. To meet this object, high risk communities within the wildland-urban interface were identified and publicized in the Federal Register in 2001. Since then, states have been responsible for updating this list. According to CAL FIRE’s list of Communities at Risk,90F 91 14 out of 15 local jurisdictions within Santa
Clara County are at high risk of damage from wildfire. The City of Mountain View is not included on this list. It is surrounded by urban development and the San Francisco Bay.

It is important to consider changing conditions when assessing the future probability of wildfires in the OA.

According to CAL FIRE,91F
92 over the last 5 years, 13 out the 20 most destructive wildfires in California’s history have occurred. Thousands of homes, business, and pieces of infrastructure were damaged or destroyed. This isn’t a new trend. Since the 1970s, the number of statewide fires has steadily been increasing. NASA’s Earth Observatory92F
93 summarized the causes of this surge of large, destructive of fires as; heat waves and droughts influenced by climate changed, a century of fire suppression, and fastgrowing populations expanding the WUI.

Despite recent storm and flooding events, the U.S. Drought Monitor indicates that most of California is still experiencing moderate to severe drought conditions. Santa Clara County is in a moderate drought and experienced the 35th driest year to date over the past 128 years in 2022. Drought leads to more severe, costly fires as it contributes to high burn intensity, the rate at which fire spreads, availability of dry fuels, and fires in typically wet parts of the state. When fuel is dry, sparks from both natural sources such as lightning and human sources like power lines, are more likely to ignite. Droughts can hamper first responder’s firefighting capabilities by reducing water reserves necessary to combat the blazes, resulting in longer lasting, wider spreading events.

According to California’s Fourth Climate Change Assessment,93F 94 the frequency of extreme wildfires may
increase, and the average area burned statewide may increase by 77% if greenhouse gas emissions continue to rise. Water resources, both in terms of rainfall and the availability of fuel for fires and water for fire suppression, also may be impacted by shifting water patterns due to climate change. 91 State of California. (n.d.). Communities at Risk. California Department of Forestry and Fire Protection. https://osfm.fire.ca.gov/divisions/community-wildfire-preparedness-and-mitigation/fire-plan/communities-at-risk/#c 92 State of California. (2023). California Department of Forestry and Fire Protection. https://www.fire.ca.gov/ 93 National Aeronautics and Space Administration Earth Observatory. (2021). What’s Behind California’s Surge of Large Fires? https://earthobservatory.nasa.gov/images/148908/whats-behind-californias-surge-of-large-fires 94 State of California. (2018). California’s Fourth Climate Change Assessment. https://climateassessment.ca.gov/

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Figure 36: Burned Hillslopes above Pulse Canyon near San Antonio Valley, SCU Lightning Complex, Santa Clara County94F
95 Changing fire management practices also impact fire risk. Early in the 20th century, fire fighters adopted practices of fire suppression, with few prescribed burns. That meant that vegetation which would have been thinned due to naturally occurring fires was allowed to become overgrown and dense. Now, decades later, the impacts of those practices are being felt. A new consensus is developing that proactive fuel treatment is critical to wildfire management.

Human behavior will also play a large role in predicting the future probability of wildfire. Human-caused fires, both accidental and arson, are the leading cause of wildfires in California. Education and outreach campaigns are important tools for reducing the risk of human-caused fires.

Further information on the impact of climate change on the probability of wildfire is included in Section 15, Tsunami.

Probability in OA: Highly Likely

8.2.4 Severity and Impacts
Potential losses from wildfire include human life, structures and other improvements, and natural resources. There are no recorded incidents of loss of life from wildfires in the OA. There have been multiple destructive wildfires in the OA destroying residences, burning thousands of acres, and forcing people to evacuate. Given the immediate response times to reported fires, the likelihood of injuries and casualties is minimal. Economic losses may also occur given the size and location of the fire event. The 95 Spangler, E. (2020). Burned hillslopes above Pulse Canyon [Photograph]. California Department of Conservation. https://www.conservation.ca.gov/cgs/landslides/recent

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extent of a wildfire can be moderate to severe and depends on the size, rate of spread, fuel type, cause, and impact on communities. The greater the extent, the more severe the wildfire will be.

The Santa Clara County CWPP states that high fire danger conditions that can support very active fire behavior may be uncommon, but when it does occur, it can have very severe and destructive potential.

Instances such as the 1985 Lexington fire burned 37 homes, 4,200 acres, and caused $7 million in damage. The 2009 Loma Pieta fire burned 669 acres, cost $2.7 million to suppress, involved 1,742 fire fighters, destroyed 1 residence, and caused 4 injuries. It is important to know while these cases are rare, the severity can be detrimental.

8.2.5 Warning Time
Wildfires are often caused by humans, intentionally or accidentally. Approximately 94% of wildfires in California are human caused.95F
96 There is no way to predict when one of these human-caused wildfires might break out. Dry seasons and droughts are factors that greatly increase fire likelihood. Dry lightning may trigger wildfires. Inclement weather can be predicted, so special attention can be paid during weather events that may include lightning. Reliable National Weather Service lightning warnings are available on average 24 to 48 hours prior to a significant electrical storm.

The National Weather Service alerts fire departments through Red Flag Warnings & Fire Weather Watches when there is critical weather and dry conditions that could lead to the development or rapid increase of wildfire activity. A Fire Weather Watch is issued when weather conditions could exist in the next 12–72 hours. A Red Flag Warning is the highest alert. It is important that all residents and visitors take step to prevent wildfires, particularly when either of these alerts are issued.

If a fire does break out and spread rapidly, residents may need to evacuate within hours or days. Once a fire has started, fire alerting is reasonably rapid in most cases. The rapid spread of cellular phone and two-way radio communications in recent years has further contributed to a significant improvement in warning time. Recent wildfires have put these warning systems to the test. Rapidly spreading severe California wildfires has left residents with only minutes to evacuate in some cases.

8.3 Cascading Impacts
Wildfires can have a range of cascading impacts, which in some cases may cause more widespread and prolonged damage than the fire itself. They strip slopes of vegetation, exposing them to greater amounts of runoff. This in turn can weaken soils and cause failures on slopes. Major landslides can occur several years after a wildfire. The following figure depicts the areas of the OA most at risk for landslides post wildfire:
96 State of California. (2023). California Department of Forestry and Fire Protection. https://www.fire.ca.gov/.

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Figure 37: Post Fire Soil Erosion Potential
Wildfires cause the contamination of reservoirs, destroy transmission lines, and contribute to flooding.

Most wildfires burn hot and for long durations which can bake soils, especially those high in clay content, thus increasing the imperviousness of the ground. This increases the runoff generated by storm events, thereby increasing the chance of flooding. Flash floods are particularly common after a wildfire. Even areas that are not traditional at high-risk to flooding can flood due to changes in the landscape post-fire.96F 97 Flooding and flood damage after fire is often more severe, as debris and ash left from the fire can form mudflows. As rainwater moves across charred and barren ground, it can also pick up soil and sediment and carry it in a stream of floodwaters. Impacts to the watershed can be felt for years after a wildfire. 97 Federal Emergency Management Agency. (2020, November). FEMA Fact Sheet Flood after Fire: Flood Risks Increase after Fires. https://www.fema.gov/sites/default/files/documents/fema_flood-after-fire_factsheet_nov20.pdf

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Fires can cause direct economic losses in the reduction of harvestable timber and indirect economic losses in reduced tourism. Cultural and historic resources, scenic vista, and recreational areas may burn.

Fire and smoke can reduce employee’s ability to go to work, decrease productivity, and delay outdoor projects. Adapting to these conditions will cost businesses, consumers, and governments.97F 98 Wildfires can
also affect personal and household economics through loss of income, increased medical costs, and property damage that may not be covered by insurance.

Wildlife can also be impacted by wildfires. After the historic wildfire seasons California has seen recently, there were increased sighting of animals such as mountain lions, raccoons, and coyotes in urban neighborhoods. Wildfires may be one reason why they are encroaching on urban areas, both putting urban populations at risk from these animals and exposing these animals to the risk humans present to them.

8.3.1 Smoke and Air Quality
Smoke exposure is one of the most concerning secondary impacts of wildfires. Smoke generated by wildfire consists of visible and invisible emissions that contain particulate matter (soot, tar, water vapor, and minerals), gases (carbon monoxide, carbon dioxide, nitrogen oxides), and toxics (formaldehyde, benzene). Emissions from wildfires depend on the type of fuel, the moisture content of the fuel, the efficiency (or temperature) of combustion, and the weather. The biggest threat from smoke is fine particles. Fine particles in smoke can get into eyes and respiratory systems, cause burning eyes, runny noses, and illness like bronchitis, as well as aggravate chronic heart and lung disease potentially resulting in premature death for people with these conditions.98F 99 The inhalation of wildfire smoke can harm many
and become fatal. Wildfire smoke is known to be even more dangerous than wildfire flames and burns.

Wildfire smoke is rolling back decades of investments in improving air quality in the U.S. Over the last decade, the estimated amount of each individual’s exposure to light, medium, and heavy wildfire smoke has gone up.9F
100 The rapid acceleration of poor air quality days and number of people exposed is particularly concerning. One study found a 27% increase in people annually exposed to a particle pollution known as PM2.5 – an increase from less than half a million people only a decade ago to over eight million exposed on at least one day a year ago now10F 101. Smoke does not recognize jurisdictional
boundaries. The impact of this hazard can be felt far from its source. Wildfires started outside of the OA, from northern California to Oregon, have brought smoke to the Bay Area in recent years.

Severe smoke events are expected to only get worse as climate change increases the frequency and severity of wildfires. This poses a chance to exasperate already challenging air quality issues. According to the American Lung Association’s 2023 State of the Air report, Santa Clara County received a grade of “F”. An estimated almost 1.9 million people within the OA are considered to be at risk from poor air quality. While wildfires are certainly not the only source of air pollution, the increase in wildfire smoke in recent years has still demonstrated the serious impact of poor air quality across sectors. 98 Lappe, B. & Vargo, J. (2022, November). Disruptions from Wildfire Smoke: Vulnerabilities in Local Economies and Disadvantaged Communities in the U.S. Federal Reserve Bank of San Francisco. https://www.frbsf.org/communitydevelopment/publications/community-development-research-briefs/2022/november/disruptions-from-wildfire-smoke/ 99 Environmental Protection Agency. (2021, June 16). Wildfires and Indoor Air Quality (IAQ). https://www.epa.gov/indoor-air-quality-iaq/wildfires-and-indoor-air-quality-iaq 100 Lappe, B. & Vargo, J. (2022, November). Disruptions from Wildfire Smoke: Vulnerabilities in Local Economies and Disadvantaged Communities in the U.S. Federal Reserve Bank of San Francisco. https://www.frbsf.org/communitydevelopment/publications/community-development-research-briefs/2022/november/disruptions-from-wildfire-smoke/ 101 Garthwaite, J. (2022, September). Stanford researchers find wildfire smoke is unraveling decades of air quality gains, exposing millions of Americans to extreme pollution levels. Wildfire smoke is unraveling decades of air quality gains | Stanford News

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Smoke and poor air quality disproportionately impacts vulnerable populations and frontline workers (those in outdoor occupations typically without air filtration). The most vulnerable to smoke’s impacts include the elderly, children, people with pre-existing conditions including respiratory and cardiovascular diseases, communities of color, and low-income populations. One of the most common pieces of advice to people during a severe smoke event is to stay indoors. However, particularly in inadequate housing situations or when people do not have the means to evacuate, simply staying indoors is not sufficient considering how smoke can infiltrates buildings through windows and doors, vents, air conditioning, and small cracks or other openings. Additional measures such as clean air centers, masks, and air purifiers may be required.

Smoke is as disruptive as it is deadly. Exposure to air pollution by children can reduce lung growth, inhibit brain development, and increase the risk of health conditions like asthma.10F 102 Children’s education can
also be disrupted, resulting in decreased test scores and educational attainment. Although these impacts may be hard to quantify now, it is likely those exposed will be experiencing them for years to come. The economy is also impacted through decrease labor income, employment, and labor force participation.

Wildfire smoke reduced earnings across the country by an estimated $125 billion a year between 2007 and 2019.102F
103

8.4 Exposure

8.4.1 Population
Population could not be examined by wildfire hazard classification because the boundaries of census block groups do not coincide with the zone boundaries. However, population was estimated using the residential building count in the areas of moderate to high hazard and multiplying by the 2017-2021 US Census Bureau average population per household for Santa Clara County. Table 43 presents the results.

Hazus 6.0 demographic data indicates that 260,705 persons or 13.5 percent of the population in the OA are over 64 years old, and 422,719 persons or 21.8 percent of the population within the OA under 18 years of age. These ages groups may experience worse affects from poor air quality resulting from a wildfire. They may also have a greater dependency on assistance from others in the event of an evacuation.
102 United Nations Environment Programme. (October 2018). Young and old, air pollution affects the most vulnerable.

Young and old, air pollution affects the most vulnerable (unep.org) 103 Stanford Institute for Economic Policy Research. (December 2022). Wildfires reveal the large toll of air pollution on labor market outcomes. Wildfires reveal the large toll of air pollution on labor market outcomes | Stanford Institute for Economic Policy Research (SIEPR)

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Table 43: Population Within Wildfire Hazard Areas
Jurisdiction
Number of Buildings in Wildfire Hazard Area Population in Wildfire Hazard Area Residential Public Industrial Commercial
Total
Number of
Buildings
Population % of Total
Population
Campbell 83 1 1 0 85 247 0.57
Cupertino 2,116 4 5 42 2,167 6,306 10.40
Gilroy 4,426 7 40 109 4,582 13,189 22.18
Los Altos 1,019 7 10 31 1,067 3,037 9.55
Los Altos Hills 2,305 5 20 65 2,395 6,869 81.27
Los Gatos 2,789 9 23 87 2,908 8,311 24.79
Milpitas 1,401 2 17 36 1,456 4,175 5.20
Monte Sereno 535 0 2 13 550 1,594 46.21
Morgan Hill 5,237 17 56 167 5,477 15,606 34.65
Mountain View 318 1 1 30 350 948 1.15
Palo Alto 574 3 4 23 604 1,711 2.50
San José 15,507 44 118 453 16,122 46,211 4.56
Santa Clara (city) 109 0 0 4 113 325 0.25
Saratoga 2,823 7 33 96 2,959 8,413 27.10
Sunnyvale 348 2 6 10 366 1,037 0.67
Unincorporated
County 10,913 66 242 664 11,885 32,521 36.03
Total 50,503 175 578 1830 53,086 150,499 7.78

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8.4.2 Property
Property damage from wildfires can significantly alter entire communities. The number of structures in each FHSZ within the OA and their values are summarized in Table 44. Table 45 shows the general land use of parcels exposed to the wildfire hazard in unincorporated areas of the OA. According to the Santa Clara County CWPP, there are 107 properties and districts listed on the National Register of Historic Places in Santa Clara County. Many of these sites are urban, but some are within the WUI. The Lick Observatory is one such place of historic and cultural significant which was almost burned due to a recent wildfire.

Table 44: Exposure and Value of Structures in Moderate to High Wildfire Hazard Areas Jurisdiction Buildings
Exposed
Value Exposed % of Total
Replacement
Structure Contents Vehicle Value
Campbell 85 $26,018,757.17 $13,518,215 $2,718,000 0.37
Cupertino 2,167 $851,005,863 $433,722,243 $66,474,000 8.17 Gilroy 4,582 $1,915,907,959 $1,063,212,359 $137,916,000 22.02 Los Altos 1,067 $443,693,069 $241,831,582 $30,906,000 8.56 Los Altos Hills 2,395 $1,234,211,033 $654,595,360 $67,059,000 71.11 Los Gatos 2,908 $1,310,513,983 $712,187,966 $93,780,000 19.75 Milpitas 1,456 $513,489,424 $279,091,477 $44,361,000 4.02 Monte Sereno 550 $269,260,704 $137,202,957 $15,273,000 43.58 Morgan Hill 5,477 $2,273,625,913 $1,266,973,143 $179,847,000 29.65 Mountain View 350 $114,334,578 $63,331,824 $14,103,000 0.88 Palo Alto 604 $319,419,553 $166,253,134 $25,092,000 2.26 San José 16,122 $6,080,110,863 $3,333,308,139 $487,431,000 4.77 Santa Clara
(city) 113 $34,986,342 $17,821,587 $3,978,000 0.16
Saratoga 2,959 $1,347,146,278 $736,302,667 $86,508,000 26.01 Sunnyvale 366 $116,046,797 $65,337,581 $15,030,000 0.53 Unincorporated
County 11,885 $5,720,386,230 $3,403,867,991 $444,906,000 44.35 Total 53,086 $22,570,157,353 $12,588,558,231 $1,715,382,000 8.14

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Table 45: Land Within the Wildfire Hazard Classification Areas Type of Land Use
Moderate
Hazard Zone
High
Hazard Zone
Very High
Hazard Zone
Area
(acres) % of total Area (acres) % of total Area (acres) % of total Campbell 7.8 0.2% 5.33 0.1% 0.69 0.0%
Cupertino 415.13 5.8% 262.34 3.6% 62.11 0.9%
Gilroy 1249.51 11.8% 1080.12 10.2% 117.51 1.1%
Los Altos 115.63 2.8% 44.83 1.1% 2.2 0.1%
Los Altos Hills 1491.83 25.7% 697.59 12.0% 38.52 0.7%
Los Gatos 929.39 12.5% 667.03 8.9% 139.32 1.9%
Milpitas 322.51 3.7% 303.12 3.5% 127.1 1.5%
Monte Sereno 142.96 13.8% 66.92 6.4% 3.56 0.3%
Morgan Hill 1131.79 13.7% 876.38 10.6% 249.36 3.0%
Mountain View 65.66 0.8% 49.97 0.6% 13.29 0.2%
Palo Alto 1246.27 7.5% 1180.12 7.1% 735.18 4.4%
San Jose 6722.21 5.8% 5036.3 4.4% 1951.14 1.7%
Santa Clara 40.39 0.3% 5.15 0.0% 0 0.0%
Saratoga 1269.79 15.5% 723.72 8.8% 71.02 0.9%
Sunnyvale 44.85 0.3% 30.79 0.2% 2.48 0.0%
Unincorporated 111,878.48 18.5% 144,629.2 24.0% 129,146.5 21.4% Total 127,074.2 15.2% 155,658.9 18.6% 132,660 15.9%

8.4.3 Critical Facilities and Infrastructure
Table 46 and Table 47 identify critical facilities exposed to the wildfire hazard in the OA. In the event of wildfire, there would likely be little damage to the majority of infrastructure. Most road and railroads would be without damage except in the worst scenarios. Power lines are the most at risk to wildfire because most are made of wood and susceptible to burning. In the event of a wildfire, pipelines could provide a source of fuel and lead to a catastrophic explosion.

The Santa Clara County Community Wildfire Protection Plan notes that there are many arterial roads and highways that are critical to transportation in the WUI. The transportation networks exposed to the WUI include Skyline/Highway 35, Summit Road, Junipero Serra Blvd/Foothill Expressway, Blossom Hill Road, Almaden Road, Old Monterey Highway, Page Mill Road, Stevens Canyon Road, Highway 9, Highway 17, Old Santa Cruz Highway, Watsonville Road, Hecker Pass/Highway 152 West, Pacheco Pass/Highway 152 East, and Mt. Hamilton Road/Highway 130.

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Table 46: Critical Facilities within Moderate to High Wildfire Hazard Areas Jurisdiction Essential
Facilities Transportation Utilities Hazardous Materials Community
Assets
Campbell 0 0 0 0 0
Cupertino 0 7 0 0 1
Gilroy 1 7 0 0 4
Los Altos 0 0 0 0 0
Los Altos Hills 0 8 0 0 1
Los Gatos 0 1 0 0 3
Milpitas 0 2 0 0 0
Monte Sereno 0 0 0 0 1
Morgan Hill 0 5 0 3 6
Mountain View 0 3 0 0 1
Palo Alto 0 1 0 0 6
San Jose 2 26 2 2 19
Santa Clara 0 1 0 0 2
Saratoga 1 9 0 0 2
Sunnyvale 0 0 0 0 0
Unincorporated 3 100 14 1 29
Total 7 170 16 6 75
Table 47: Critical Facilities Within 100 Meters of Moderate to High Wildfire Hazard Areas Jurisdiction Essential
Facilities Transportation Utilities Hazardous Materials Community
Assets
Campbell 1 7 0 0 2
Cupertino 2 11 0 0 8
Gilroy 12 29 2 2 7
Los Altos 7 6 0 0 6
Los Altos Hills 6 21 0 0 2
Los Gatos 11 25 0 0 7
Milpitas 4 24 0 0 13
Monte Sereno 0 1 0 0 1
Morgan Hill 16 14 1 5 10
Mountain View 2 26 0 2 7
Palo Alto 4 4 1 3 16
San Jose 62 207 8 19 91
Santa Clara 7 13 1 2 5
Saratoga 9 31 0 0 10
Sunnyvale 3 17 2 2 8

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Jurisdiction Essential
Facilities Transportation Utilities Hazardous Materials Community
Assets
Unincorporated 28 177 16 2 37
Total 174 610 31 37 230
There are registered hazardous material containment sites in wildfire risk zones in the OA. During a wildfire, containers for these materials could rupture due to excessive heat and act as fuel for the fire, causing rapid spreading and escalating the fire to unmanageable levels. In addition, they could leak into surrounding areas, saturating soils and seeping into surface waters, and have a disastrous effect on the environment.

Although the risk assessment did not include any modeling to determine specific damage estimates for these facilities, it does indicate a large number of assets are exposed to wildfire hazard. There are a large number of essential facilities, transportation features, and other community assets within close proximity to high wildfire hazard classification areas. Structures may be exposed to damage directly from fire.

Additionally, utility services may be disrupted, particularly areas with above ground utility systems, some of which have been identified in the 2023 CWPP. Further evaluation may be needed to consider building construction materials, landscape conditions, road access, and defensible space to further determine their susceptibility to wildfire and where specific priority mitigation actions are needed.

8.4.4 Environment
Fire is a natural and critical ecosystem process in most terrestrial ecosystems, dictating in part the types, structure, and spatial extent of native vegetation. However, wildfires can cause severe environmental impacts:
 Soil Erosion: The protective covering provided by foliage and dead organic matter is removed, leaving the soil fully exposed to wind and water erosion. Accelerated soil erosion occurs, causing landslides and threatening aquatic habitats.
 Spread of Invasive Plant Species: Non-native woody plant species frequently invade burned areas. When weeds become established, they can dominate the plant cover over broad landscapes, and become difficult and costly to control.  Disease and Insect Infestations: Unless diseased or insect-infested trees are swiftly removed, infestations and disease can spread to healthy forests and private lands. Timely active management actions are needed to remove diseased or infested trees.  Destroyed Endangered Species Habitat: Catastrophic fires can have devastating consequences for endangered species.
 Soil Sterilization: Topsoil exposed to extreme heat can become water repellant, and soil nutrients may be lost. It can take decades or even centuries for ecosystems to recover from a fire.

Some fires burn so hot that they can sterilize the soil.  Damaged Fisheries: Critical fisheries can suffer from increased water temperatures, sedimentation, and changes in water quality.

Many ecosystems are adapted to historical patterns of fire occurrence. These patterns, called “fire regimes,” include temporal attributes (e.g., frequency and seasonality), spatial attributes (e.g., size and spatial complexity), and magnitude attributes (e.g., intensity and severity), each of which have ranges of natural variability. Ecosystem stability is threatened when any of the attributes for a given fire regime diverge from its range of natural variability.

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8.5 Vulnerability
There are significant assets, including structures, systems, populations, and community lifelines, vulnerable to wildfire in the OA. In particular, the communities of Gilroy, Los Altos Hills, Los Gatos, Monte Sereno, Morgan Hill, Saratoga, and the unincorporated county have substantial percentages of their area, population, and structural value within high risk areas.

Changes in conditions: Increase in Vulnerability
• Recent drought has impacted vegetation, tree mortality and other • CMRA data indicates an increase in the annual number of days without precipitation, an increase in the number of consecutive days without precipitation, and the number of days with high temperatures. These conditions can all contribute to greater wildfire risk. • Large wildfires occur throughout California, and poor air quality from smoke from wildfire in other portions of the state contribute to poor air quality in the OA. • These climate trends are ongoing and projected to continue. • Management of fire risk requires repetitive action to manage fuels and maintain defensible space.

Vulnerability will increase without ongoing management. • Many areas throughout the OA reside in foothill areas where roads may be narrow, be located on dead end spurs, or have long drive-times to fire response facilities, which may increase the difficulty of fire suppression near these structures. Residents bear some of the burden in maintaining vegetation near their homes to try and reduce the risk of fire. • Wildfire leads to an increased risk of debris flow in burned areas, with increases vulnerability to homes and roadways in foothills following a wildfire.

8.5.1 Population
There are no recorded incidents of loss of life from wildfires within the OA. Given the immediate response times to reported fires, the likelihood of injuries and casualties is minimal; therefore, injuries and casualties were not estimated for the wildfire hazard.

That is not to say that wildfires would not impact the OA population. If any OA residents were to be injured or killed by a wildfire, besides fire responders, it would most likely be a member of a vulnerable population. This includes people with limited mobility that required assistive devices like wheelchairs or medical oxygen, people with respiratory or other illnesses, people over 60, people with a communication barrier, migrant populations, people from low-income communities, and people without regular access to a vehicle they could use to evacuate. Wildfire may threaten the health and safety of those fighting the fires too. First responders are exposed to the dangers from the initial incident and after-effects from smoke inhalation and heat stroke.

Gilroy, Los Altos hills, Los Gatos, Monte Sereno, Morgan Hill, Saratoga all have a significant percentage of their population within or close to high wildfire risk areas. People residing in these areas are at higher risk to possible injury and also from being displaced from their homes if an evacuation is required.

The public is also exposed to the negative impacts of smoke. Public health impacts associated with wildfire include difficulty in breathing, odor, and reduction in visibility. Smoke and air pollution from wildfires can be a severe health hazard, especially for vulnerable populations, including children, the elderly, outdoor workers, and those with respiratory and cardiovascular diseases. The 2018 wildfires alone were estimated to have health costs in Santa Clara County over $1.5 billion.103F 104
104 Bay Area Council Economic institute. (November 2021). The True Cost of Wildfires Analyzing the Impact of Wildfires on the California Economy. BACEI_WildfireImpacts_Nov2021.pdf (bayareaeconomy.org)

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Commuters may also be impacted. Wildfires around the Bay Area may cause route/commuter delays or disruption due to closed roadways. Some drivers may have to stay home during poor air quality days, particularly if they are part of vulnerable population including people with lung diseases such as asthma and chronic obstructive pulmonary disease, adults over 65, people with cardiovascular disaster, people who smoke, and people in poverty who lack access to healthcare.

Additionally, the California Department of Public Health104F 105 recognizes the potential negative impact of
wildfires on mental health. The stress of coping with the loss of a home, personal items, pets, livestock, and other traumatic events can trigger mood swings, sleep disruption, and cause extreme nervous tension and/or depression. Children may find it particularly challenging to cope with losses caused by wildfire and present symptoms adults may not initially recognize as a sign of this stress. A comprehensive review of mental health and fire literature found that there was increased cases of PTSD, depression, anxiety, and substance use post-fire both in short-term and long-term studies. The impacts to the populations’ mental health should be considered when evaluating the benefits and costs of alternative mitigation actions.

8.5.2 Property
Loss estimations for the wildfire hazard are not based on damage functions, because no such damage functions are currently available. Instead, loss estimates were developed representing 10 percent, 30 percent, and 50 percent of the replacement value of exposed structures. This allows emergency managers to select a range of economic impact based on an estimate of the percent of damage to the general building stock. Damage in excess of 50 percent is considered to be substantial by most building codes and typically requires total reconstruction of the structure. Table 48 lists the loss estimates for the general building stock for jurisdictions that have an exposure to a fire hazard severity zone (the aggregate of the 3 zones assessed).
105 California Department of Public Health. (2022, December 29). Wildfires & Mental Health. https://www.cdph.ca.gov/Programs/EPO/Pages/Wildfire%20Pages/Wildfires--Mental-Health.aspx

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Table 48: Loss Estimates for Wildfire within Moderate to High Wildfire Hazard Class Jurisdiction Exposed Value
Estimated Loss Potential from Wildfire
10% Damage 30% Damage 50% Damage
Campbell $42,254,972.95 $4,225,497.30 $12,676,491.89 $21,127,486.48 Cupertino $1,351,202,106.61 $135,120,210.66 $405,360,631.98 $ 675,601,053.31 Gilroy $3,117,036,318.53 $311,703,631.85 $935,110,895.56 $1,558,518,159.27 Los Altos $716,430,652.27 $71,643,065.23 $214,929,195.68 $358,215,326.14 Los Altos Hills $1,955,865,393.65 $195,586,539.37 $586,759,618.10 $977,932,696.83 Los Gatos $2,116,481,950.18 $211,648,195.02 $634,944,585.05 $1,058,240,975.09 Milpitas $836,941,901.80 $83,694,190.18 $251,082,570.54 $418,470,950.90 Monte Sereno $421,736,661.94 $42,173,666.19 $126,520,998.58 $210,868,330.97 Morgan Hill $3,720,446,057.04 $372,044,605.70 $1,116,133,817.11 $1,860,223,028.52 Mountain View $191,769,402.82 $19,176,940.28 $57,530,820.85 $95,884,701.41 Palo Alto $510,764,687.23 $51,076,468.72 $153,229,406.17 $255,382,343.62 San José $9,900,850,002.92 $990,085,000.29 $2,970,255,000.88 $4,950,425,001.46 Santa Clara (city) $56,785,930.11 $5,678,593.01 $17,035,779.03 $28,392,965.06 Saratoga $2,169,956,945.61 $216,995,694.56 $650,987,083.68 $1,084,978,472.81 Sunnyvale $196,414,379.07 $19,641,437.91 $58,924,313.72 $98,207,189.54 Unincorporated
County $9,569,160,222.23 $956,916,022.22 $2,870,748,066.67 $4,784,580,111.12 Total $36,874,097,584.96 $3,687,409,758.50 $11,062,229,275.49 $18,437,048,792.48 It should be noted that of the 53,086 structures in the OA determined to be at risk to wildfire, 50,503 are residences. This places a high burden of loss directly on individual homeowners. It may also coincide with a large number of people displaced, both for short-term evacuations, or possibly long-term if homes are lost to wildfire.

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8.5.3 Critical Facilities and Infrastructure
As shown in Table 47, many essential facilities and infrastructure are in close proximity to areas at high risk to wildfire. Individual facility and structure types within the hazard areas were not counted. Essential facilities at risk could include schools, fire or police stations, or hospitals that are near the high wildfire risk classification zones. It is expected that most of the transportation facilities potentially include railway, light rail, or highway bridges. Air and rail facilities are predominantly in more developed urban areas with less direct risk to wildfire. Several electric power facilities are located near high hazard areas.

Critical facilities of wood frame construction are especially vulnerable during wildfire events. Roads and railroads could be damaged by fallen trees, slides, debris flows, cracking, heavy fire fighting vehicles, and loss of signs and road delineators. Narrow one-lands roads are common in communities throughout the county. Fires can create conditions that block or prevent access and can isolate residents and emergency service providers. Wildfire typically does not have a major direct impact on bridges, but it can create conditions in which bridges are obstructed. Many bridges in areas of high to moderate fire risk are important because they provide the only ingress and egress to large areas and in some cases to isolated neighborhoods.

Communications and power and gas distribution infrastructure may also be threatened. Power lines are the most at risk from wildfire because most poles are made of wood and susceptible to burning. In 2018, Pacific Gas & Electric, the primary gas and electricity supplier to the northern half of California, declared bankruptcy following the 2017 and 2018 northern California wildfire. This bankruptcy has been called the first climate change bankruptcy (Center on Global Energy Policy).105F 106 It serves as an important case study
for how to understand risk to critical infrastructure and the many stakeholders impacted.

The function of critical facilities and infrastructure may also be impacted by fire mitigation measures, such as public safety power shutoffs. Electrical transmission and distribution lines may ignite fires if they are downed by winds and/or trees. To reduce this risk, electrical grids or blocks of an area may be deenergized during heightened risk conditions. This is important for critical facilities to be aware of and prepare for in order to reduce disruptions.

8.5.4 Wildlife and Livestock
The Santa Clara County CWPP Plan notes that horses, livestock, and animals may be especially vulnerable if a wildfire occurs. Many rural homes in the OA have horses, other large animals, and livestock. Farm animals and pets are common in homes of the OA. It can be difficult to evacuate large animals during a wildfire, and they can be harmed by smoke and other wildfire impacts. The loading of horses during a fire, and transportation of stock vehicles down narrow roads under stressful situations can be difficult. Other wildlife, like birds, are highly vulnerable during wildfires due to habitat destruction, smoke inhalation, loss of food sources, and even adverse effects on rare and specialized species.

8.6 Future Trends in Development
The population of Santa Clara County increase 8.7% between 2010 and 2020. However, the population has begun to decline in recent years any future growth is expected at a slow rate. The highly urbanized portions of the OA have little or no wildfire risk exposure. Development in the wildland urban interface can be managed with strong fire-resilient land use and building codes. Santa Clara County has been a leader 106 Center on Global Energy Policy. (2020, January 28). Out of Control: The Impact of Wildfires on our Power Sector and the Environment. https://www.energypolicy.columbia.edu/publications/out-control-impact-wildfires-our-powersector-and-environment

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in urban planning for decades. Planning partners have taken steps to reduce geographic spread into wildland areas and promote “smart growth,” which includes focusing on moderate to higher density development near existing infrastructure.106F
107 These efforts have been fairly effective in accommodating residential growth without significant urban encroachment. However, despite these efforts, as population grows, it is likely the development of wildland will continue, and the WUI will grow. In some cases, parcels may be developed without a planning permit. New development is also occurring in areas that have limited water supply, putting residents at risk. The technology industry is a major employer in the county.

Many employees of tech-based industries are choosing to build property in the Santa Clara foothills, creating additional concerns around the value of property in the WUI, proper fire-resident landscaping, and gated communities.

Overall though, this plan has assessed capabilities with regards to the tools necessary to encourage fireresilient future development and found the OA was equipped with sufficient resources. In fact, the OA was actively involved in expanding planning capabilities at the time of this plan update. The Santa Clara County General Plan and individual city General Plans also address wildfire and can reduce risk through developing land use policies for hazard prone areas (e.g., proper community design, open space land use, and reducing population in areas prone to wildfire). The Safety Element of the Santa Clara County General Plan is currently being updated. Updating the Safety Element will ensure safety considerations are identified and included during the decision-making and planning processes as they relate to future developments within the county. The Safety Element addresses Wildland/Urban Fire risk.

The Santa Clara County Community Wildfire Protection Plan (CWPP)107F 108 is also currently being updated
and will outline a mitigation and preparedness plan to reduce wildfire risk. The CWPP advocates for wildfire risk reduction measures including updating applicable policies, codes, and ordinances, prioritizing fuel reduction, improving available water supply networks, and engaging in outreach and education. It emphasizes property’s owners’ responsibility to reduce structure ignitability and mitigate risk.

8.7 Scenario
A major wildfire in the OA might begin with a water shortage causing tinder-like wildlands and “Red Flag” conditions occurring, indicating a combination of higher-than-normal temperatures, low humidity and winds blowing from the east across California to the ocean. Lightning strikes or human carelessness with combustible materials could trigger a multitude of small, isolated fires.

The embers from these smaller fires could be carried miles by hot, dry winds. Fires that start in flat areas move slower, but wind still pushes them. It is not unusual for a wildfire pushed by wind to burn the ground fuel and later climb into the crown and reverse its track. This is one of many ways that fires can escape containment, typically during periods when response capabilities are overwhelmed. These small new fires would most likely merge. Suppression resources would be redirected from protecting the natural resources to saving more remote subdivisions.

The worst-case scenario would include an active fire season throughout the American west, spreading resources thin. Firefighting teams would be exhausted or unavailable. Many federal assets would be responding to other fires that started earlier in the season. Multiple fires burn in the State or OA at one time would limit State and local capabilities to respond.

If fire management capabilities are stretched too thin, and weather conditions remained favorable for wildfires, the fire could encroach upon the WUI. Losses in the WUI could be devastating. Residents would need to evacuate, residential and commercial properties would be damaged or destroyed, lives could be 107 Santa Clara County Fire Department. (2016, August). Santa Clara Community Wildfire Protection Plan. https://www.sccfd.org/santa-clara-county-community-wildfire-protection-plan/ 108 Santa Clara County FireSafe Council (2019). https://sccfiresafe.org/cwpp/

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lost, and infrastructure and utilities including communication towers, power grids, water utilities, transportation corridors and community watersheds could be impacted.

To further complicate the problem after the fire has been contained, heavy rains could follow, causing flooding and landslides and releasing tons of sediment into rivers, and damaging sensitive habitat and riparian areas. Such a fire followed by rain could release millions of cubic yards of sediment into streams, creating new floodplains and changing existing ones. With the vegetation removed from the watershed, stream flows could easily double. Floods that could be expected every 50 years may occur every couple of years. With the streambeds unable to carry the increased discharge because of increased sediment, the floodplains and floodplain elevations would increase. Floodplain management capabilities would find it challenging to adapt to changed conditions and new flood map studies would be warranted.

8.8 Issues
Important issues associated with wildfires in the OA include the following:
 Public education and outreach to people living in or near the fire hazard zones should include information about and assistance with mitigation activities such as defensible space, and advance identification of evacuation routes and safe zones.
 Wildfires could cause landslides as a secondary natural hazard.  Climate change could affect the wildfire hazard.
 Future growth into interface areas should continue to be managed.  Area fire districts need to continue to train on wildland-urban interface events.  Vegetation management activities. This would include enhancement through expansion of the target areas as well as additional resources.
 Regional consistency of higher building code standards such as residential sprinkler requirements and prohibitive combustible roof standards.
 Fire department water supply in high-risk wildfire areas.  Expand certifications and qualifications for fire department personnel. Ensure that all firefighters are trained in basic wildfire behavior, basic fire weather, and that all company officers and chief level officers are trained in the wildland command and strike team leader level.

Table 49: EMAP Consequence Analysis: Wildfire
Subject Ranking Impacts/Wildfire
Public Minimal to
Severe
Residents in the high wildfire risk zones are most likely to be impacted. Impacts include injuries related to burns, smoke inhalation, and loss of property and homes. Residents outside of the immediate wildfire area may still be impacted by a wildfire event due to smoke, disruption of services, or inaccessible roads.

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Subject Ranking Impacts/Wildfire
Responders Minimal Responders will be called upon to manage the overall incident including potentially supporting evacuations, closing roads, assisting injured members of the public, and more. Climate conditions also need to be considered. Fire management
agencies face more uncertainty in planning, change in
suppression and fire management techniques, and the need for more agency coordination considering compounding hazards like drought. With proper training, data, equipment, and time for responders with pre-existing conditions to take precautionary steps to protect themselves prior to exposure, it is anticipated the impact to responders will be minimal.

Continuity of
Operations (including
continued delivery of
services)
Minimal to
Moderate
The impacts on continuity of operations depends largely on the location of the fire and whether any facility or critical infrastructure component would be impacted. Each fire will present unique risks.

Communication systems could be damaged or destroyed. Power connectivity could be disrupted. Other community lifelines could be disrupted or destroyed. Delivery of services may be slowed or stopped in impacted areas.

Property, Facilities,
and Infrastructure
Minimal to
severe
The localized impact to properties, facilities, and infrastructure could be severe. The impact to critical infrastructure depends in part on the preparation taken prior to a fire during high-risk warning levels (e.g., raising water levels and fueling generators).

Fire conditions and the ability of responder’s to quickly suppress the fire will also play a large role in determining the impact.

Environment Minimal to
severe
Fire plays an important role in California’s ecosystem. A wildfire does not necessarily have a negative impact on the environment.

However, fires can also have severe negative impact in terms of habitat destruction, soil erosion, soil sterilization, spread of invasive species, and disease and insect infestation.

Economic
Conditions
Minimal to
severe
Impacts on the economy will depend greatly on the size and location of the wildfire event. A major wildfire event could impact the local economy through the destruction of property,
businesses, and infrastructure; delays or halts in supply chains; and impacts to health and air quality, which may decrease worker productivity or prevent workers from going to work.

Public Confidence in
the Government
Minimal to
severe
The public’s confidence will vary, depending on the perception of how well the event was managed, the warning time, and the time it takes for response and recovery. Timely and accurate public information and notification during these events will impact public trust.

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9 Inclement Weather
Definitions
• Atmospheric River: A long, narrow region in the atmosphere that transports most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying large amounts of water vapor and strong winds. When atmospheric rivers make landfall, they release this vapor in the form of rain or snow, causing flooding and mudslide events.
• Damaging Winds: Winds exceeding 50–60 mph. NOAA identifies eight types of damaging winds. • Extreme Heat: A period of high heat and humidity with temperatures above 90 degrees for at least two to three days.
• Extreme Temperatures: Unexpected, unusual, or unseasonal temperatures—cold or hot—that can create dangerous situations.
• Heat Index: The temperature the body feels when heat and humidity are combined. • Heavy Precipitation: Also known as heavy rain, refers to instances where the amount of rain or snow experienced in one area exceeds what is normal.
• Space Weather: Variations in the space environment between the sun and earth. It can influence the performance of technology used on Earth.
• Thunderstorm: A rain event that includes thunder, lightning and occasionally strong gusty winds and hail.

9.1 General Background
Inclement weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life. Inclement weather can be categorized into two groups: systems that form over wide geographic areas are classified as general severe weather; those with a more limited geographic area are classified as localized severe weather. In this plan, we refer to this hazard by the broad “inclement weather” term. Inclement weather, technically, is not the same as extreme weather, which refers to unusual weather events at the extremes of the historical distribution for a given area.

The most common inclement weather events that impact the Santa Clara County OA are heavy rains/atmospheric rivers/, extreme weather (hot and cold), high wind, and space weather. These types of inclement weather are described in the following sections. Flooding issues associated with inclement weather are discussed in Section 13.

Inclement weather episodes account for the majority of OEM EOC activations since 2017. Each year since the last plan update, Santa Clara County has experienced an average of 10 inclement weather episodes (cold and hot). The Office of Emergency Management has a robust system for coordinating response across multiple jurisdictions during inclement weather episodes. The process is described in the Inclement Weather Annex to the Emergency Operations Plan. This annex was developed in cooperation with over 40 area stakeholders representing more than 20 different agencies.

9.1.1 Heavy Precipitation/Atmospheric River
Most severe storms in the Santa Clara County OA consist of atmospheric rivers, heavy rains, hail, and thunderstorms.

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Heavy precipitation, or heavy rain, refers to instances where the amount of rain or snow experienced in one area exceeds what is normal.108F
109 The amount of precipitation needed to qualify as heavy rain varies with each location and season. Heavy rain is distinct from climate change analyses on increasing precipitation. It does not mean that the total amount of precipitation at a location has increased, just that the rain is occurring in a more intense event. More frequent heavy rain events, however, can serve as indicators of changing precipitation levels. Heavy precipitation is measured by tracking the event frequency, analyzing the mean return period, and by measuring the amount of precipitation within a specific timeframe, such as the inches of rain within a 24-hour period.

Rainfall intensity is based on the amount of rainfall per unit of time. Light rain is typically less than 0.1 inch per hour, moderate rain is .1 to .3 inches of rain per hour, heavy rain is .3 to 2 inches per hour, and violent rain can be used to characterize rates greater than 2 inches per hour.109 F 110
Figure 38: NOAA Atlas Intensity - Santa Clara, California According to the NOAA, about 30 to 50 percent of annual precipitation in the west coast states, such as California, are due to atmospheric river events. Atmospheric Rivers are long, concentrated regions in the atmosphere that transport moist air away from the tropics and into higher latitudes. When combined with high wind, they produce large amounts of heavy rain and snow which can lead to flash floods, mudslides and significant damage to life and property.10F 111
109 United States Environmental Protection Agency. (2021 April). Climate Change Indicators: Heavy Participation. https://www.epa.gov/climate-indicators/climate-change-indicators-heavyprecipitation#:~:text=%22Heavy%20precipitation%22%20refers%20to%20instances%20during%20which%20the,can %20affect%20the%20intensity%20and%20frequency%20of%20precipitation. 110 Rain rate intensity classification. Manual of Surface Weather Observations. https://www.baranidesign.com/faqarticles/2020/1/19/rain-rate-intensity-classification 111 National Oceanic and Atmospheric Administration Research News. (2023, January 11). Atmospheric Rivers: What are they and how does NOAA study them? https://research.noaa.gov/article/ArtMID/587/ArticleID/2926/AtmosphericRivers-What-are-they-and-how-does-NOAA-studythem#:~:text=Infographic%3A%20The%20science%20behind%20atmospheric%20rivers%20%28NOAA%29%20Atm ospheric,and%20snow%20upon%20landfall%2C%20especially%20over%20mountainous%20terrain.

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A thunderstorm is a rain event that includes thunder, lightning and occasionally strong gusty winds and hail.1F
112 A thunderstorm is classified as “severe” when it contains one or more of the following: hail one inch or greater, winds gusting in excess of 50 knots (57.5 mph), or tornado. Thunderstorms are usually short in duration (seldom more than two hours). Heavy rains associated with thunderstorms can lead to flash flooding during the wet or dry season. According to the American Meteorological Society Glossary of Meteorology, thunderstorms are reported as light, medium, or heavy according to the following characteristics:12F
113
 Nature of the lightning and thunder
 Type and intensity of the precipitation, if any
 Speed and gustiness of the wind
 Appearance of the clouds
 Effect on surface temperature
Three factors cause thunderstorms to form: moisture, rising unstable air (air that keeps rising when disturbed), and a lifting mechanism to provide the disturbance. The sun heats the surface of the earth, which warms the air above it. If this warm surface air is forced to rise (hills or mountains can cause rising motion, as can the interaction of warm air and cold air or wet air and dry air) it will continue to rise as long as it weighs less and stays warmer than the air around it. As the air rises, it transfers heat from the surface of the earth to the upper levels of the atmosphere (the process of convection). The water vapor it contains begins to cool and it condenses into a cloud.

The cloud eventually grows upward into areas where the temperature is below freezing. Some of the water vapor turns to ice and some of it turns into water droplets. Both have electrical charges. Ice particles usually have positive charges, and rain droplets usually have negative charges. When the charges build up enough, they are discharged in a bolt of lightning, which causes the sound waves we hear as thunder.

Thunderstorms have three stages (see Figure 38):
 Developing Stage: The developing stage of a thunderstorm is marked by a cumulus cloud that is being pushed upward by a rising column of air (updraft). The cumulus cloud soon looks like a tower (called towering cumulus) as the updraft continues to develop. There is little to no rain during this stage but occasional lightning. The developing stage lasts about 10 minutes.  Mature Stage: The thunderstorm enters the mature stage when the updraft continues to feed the storm, but precipitation begins to fall out of the storm, and a downdraft begins (a column of air pushing downward). When the downdraft and rain-cooled air spread out along the ground, they form a gust front, or a line of gusty winds. The mature stage is the most likely time for hail, heavy rain, frequent lightning, strong winds, and tornadoes. The storm occasionally has a black or dark green appearance.
 Dissipating Stage: Eventually, a large amount of precipitation is produced, and the updraft is overcome by the downdraft beginning the dissipating stage. At the ground, the gust front moves out a long distance from the storm and cuts off the warm moist air that was feeding the thunderstorm. Rainfall decreases in intensity, but lightning remains a danger. 112 National Oceanic and Atmospheric Administration National Severe Storms Laboratory. (n.d.). Severe Weather 101-Thunderstorm Basics. https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/ 113 American Meteorological Society Glossary of Meteorology. (2022). Thunderstorm. https://glossary.ametsoc.org/wiki/Thunderstorm#:~:text=(Sometimes%20called%20electrical%20storm.),rain%2C%20 and%20sometimes%20with%20hail.

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Figure 39: Thunderstorm Life Cycle13F
114
There are different types of thunderstorms identified by the NOAA and some are listed below14F 115:
 Single-Cell Thunderstorms: Single-cell thunderstorms are small and brief. They usually grow and die within an hour and may produce brief heavy rain and lightning.  Multi-Cell Storm: A multi-cell storm is the most common type of thunderstorm in which new updrafts form along the leading edge of cool air. Single cells usually last 30 to 60 minutes while multi-cell storm systems may last for many hours. They may produce hail, strong winds, brief tornadoes, and flooding.
 Squall Line: A squall line is a group of storms arranged into a line, often accompanied by squalls or gusty winds and heavy rains. They tend to pass quickly and are less likely to produce tornadoes. They are usually 10 or 20 miles wide but can be up to hundreds of miles long.  Supercell: A supercell is a long-lived (usually greater than 1 hour) and highly organized storm that feeds off an updraft (a rise of current air) that is tilted and rotating. This rotating updraft can be as large as 10 miles in diameter and up to 50,000 feet tall and can be present as much as 20 to 60 minutes before a tornado forms. This rotation is called a mesocyclone when it is detected by a Doppler radar. The tornado is a small extension of this larger rotation. Most large and violent tornadoes come from supercells.

A thunderstorm is a storm with lightning and thunder produced by cumulonimbus clouds, usually producing gusty winds, heavy rain, and sometimes hail. Thunderstorms are usually short in duration (seldom more than two hours). Heavy rains associated with thunderstorms can lead to flash flooding during the wet or dry season. According to the American Meteorological Society Glossary of Meteorology, thunderstorms are reported as light, medium, or heavy according to the following characteristics:
• Nature of the lightning and thunder
• Type and intensity of the precipitation, if any
• Speed and gustiness of the wind
114 National Oceanic and Atmospheric Administration National Severe Storms Laboratory. (n.d.). Severe Weather 101-Thunderstorms. https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/ 115 National Oceanic and Atmospheric Administration National Severe Storms Laboratory. (n.d.). Severe Weather 101-Thunderstorm Types. https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/types/

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• Appearance of the clouds
• Effect on surface temperature

9.1.2 Extreme Temperatures
Extreme temperatures are unexpected, unusual, or unseasonal temperatures—cold or hot—that can create dangerous situations.

Extreme cold temperatures are below normal temperatures that may lead to serious health problems.

Exposure to the extreme cold can lead to hypothermia and frostbite in people exposed to the weather without adequate clothing protection. It may result in death if it exacerbates preexisting chronic conditions. The NWS provides a Wind Chill Chart to calculate the dangers from winter winds and freezing temperatures. Wind chill is represented by the actual air temperature factored in by wind speed. Figure 39 displays the extent and intensity by the time it takes to develop frostbite.

Figure 40: National Weather Service Wind Chill Chart
The NOAA Weather Prediction Center also has a Winter Storm Severity Index (WSSI) tool. This tool communicates the general level of severe winter weather and can be viewed in the figure below. The levels range from “minor” to “extreme.”

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Figure 41: Winter Storm Severity Index
According to FEMA, extreme heat is defined as a period of high heat and humidity with temperatures above 90 degrees for at least two to three days.15F
116 Heat is the primary cause of weather-related death in the United States and can be very taxing on the human body. Vulnerable populations such as young children, infants, people with chronic medical conditions, and pregnant women are at higher risk of heat related illness. The heat index is the temperature the body feels when heat and humidity are combined.16F
117 The direct relationship between humidity and heat can affect the severity of extreme heat events. The graphic from the NWS below classifies the level of severity in relation to the heat index. 116 U.S. Department of Homeland Security. (2022, August 1). Extreme Heat. https://www.ready.gov/heat 117 National Oceanic and Atmospheric Administration National Weather Service. (n.d.). Heat Forecast Tools. https://www.weather.gov/safety/heat-index

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Figure 42: National Weather Service Heat Index Chart17F 118
Figure 43: National Weather Service Heat Index Classifications and Corresponding Effects on the Body18F
119

9.1.3 High Winds
High Winds can occur during severe thunderstorms, with strong weather systems, or can flow down a mountain. High winds are defined as winds of 40 mph or greater lasting for an hour or more, and gusts to 58 mph or greater (NOAA). Windstorms are especially dangerous in areas with significant tree stands and areas with exposed property, poorly constructed buildings, mobile homes (manufactured housing units), major infrastructure, and above-ground utility lines. A windstorm can topple trees and power lines, cause damage to residential, commercial, and critical facilities, and leave tons of debris in its wake. 118 National Oceanic and Atmospheric Administration National Weather Service. (n.d.). What is the heat index? https://www.weather.gov/ama/heatindex
119 National Oceanic and Atmospheric Administration National Weather Service. (n.d.). What is the heat index? https://www.weather.gov/ama/heatindex

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Damaging winds are classified as those exceeding 50–60 mph.19 F 120 Damage from such winds accounts
for half of all severe weather reports in the lower 48 states and is more common than damage from tornadoes. Wind speeds can reach up to 100 mph and can produce a damage path extending for hundreds of miles.

NOAA identifies eight types of damaging winds120F
121:
 Straight-line Wind: Any thunderstorm wind that is not associated with rotation; this term is used mainly to differentiate from tornado winds.
 Downdraft: A small-scale column of air that rapidly sinks toward the ground.  Downburst: Downburst is the general term for all localized strong wind events that are caused by a strong downdraft within a thunderstorm.
 Macroburst: An outward burst of strong winds near the surface with horizontal dimensions larger than 4 km (2.5 mi) and occurs when a strong downdraft reaches the surface. Macroburst winds may begin over a smaller area and then spread out over a wider area, sometimes producing damage similar to a tornado. Although usually associated with thunderstorms, macrobursts can occur with weak showers.
 Microburst: A small, concentrated downburst that produces an outward burst of damaging winds at the surface. Microbursts are small, usually less than 4 km across, and short-lived, lasting only 5 to 10 minutes, with maximum wind speeds sometimes exceeding 100 mph. There are two kinds of microbursts: wet and dry. A wet microburst is accompanied by heavy precipitation at the surface. Dry microbursts, common in places like the high plains and the intermountain west, occur with little or no precipitation reaching the ground.  Gust Front: A gust front is the leading edge of rain-cooled air that clashes with warmer thunderstorm inflow. Gust fronts are characterized by a wind shift, temperature drop, and gusty winds out ahead of a thunderstorm. Sometimes the winds push up air above them, forming a shelf cloud or detached roll cloud.
 Derecho: A widespread, long-lived windstorm that is associated with a band of rapidly moving showers or thunderstorms. It consists of numerous microbursts, downbursts, and downburst clusters. By definition, if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length, then the event may be classified as a derecho.
 Haboob: A wall of dust that is pushed out along the ground from a thunderstorm downdraft at high speeds.

The Beaufort Scale is a classification system that relates wind speed to observed conditions. As shown in Figure 9-6, this scale indicates likely conditions that can be observed at increasing wind speed levels. 120 National Oceanic and Atmospheric Administration National Severe Storms Laboratory. (n.d.). Severe Weather 101-Damaging Winds Basics. https://www.nssl.noaa.gov/education/svrwx101/wind/ 121 National Oceanic and Atmospheric Administration National Severe Storms Laboratory. (n.d.). Severe Weather 101-Types of Damaging Winds. https://www.nssl.noaa.gov/education/svrwx101/wind/types/

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Figure 44: The Beaufort Wind Scale12F
122
122 National Weather Service. Beaufort Scale. Estimating Wind Speed and Sea State. https://www.weather.gov/pqr/beaufort

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9.1.4 Space Weather
Space weather refers to conditions resulting from solar activity that can potentially affect Earth, our atmosphere, and the near-Earth environment.12F
123 Our planet’s atmosphere helps protect us from solar radiation, but occasional eruptions of radiation and matter can disrupt our power grids and communications systems, as well as impact satellite operations and GPS navigation capabilities.

In severe cases, it produces solar energetic particles, which can damage satellites used for commercial communications, global positioning, intelligence gathering, and weather forecasting.

NOAA’s Space Weather Prediction Center has developed space weather scales. The scales describe the environmental disturbances for three event types: geomagnetic storms, solar radiation storms, and radio blackouts. The scales have numbered levels to convey severity, similar to hurricanes, tornadoes, and earthquakes. They list possible effects at each level, show the frequency of such events, and help measure of the possible intensity of the physical causes.

The NOAA space weather scales are included in Table 50, Table 51, and Table 52. NOAA studies have determined that different types of space weather may occur separately. 123 National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service. (n.d.). Space Weather. https://www.nesdis.noaa.gov/next-generation/space-weather

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Table 50: NOAA Geomagnetic Storms Space Weather Scale and Potential Effects123F 124
124 National Oceanic and Atmospheric Administration. (2011, April 7). Space Weather Scales. https://swpc-drupal.woc.noaa.gov/noaa-scalesexplanation#:~:text=The%20NOAA%20Space%20Weather%20Scales%20were%20introduced%20as,and%20their%20possible%20effects%20on%20people%20 and%20systems.

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Table 51: NOAA Solar Radiation Storms Space Weather Scale and Potential Effects124F 125
125 National Oceanic and Atmospheric Administration. (2011, April 7). Space Weather Scales. https://swpc-drupal.woc.noaa.gov/noaa-scalesexplanation#:~:text=The%20NOAA%20Space%20Weather%20Scales%20were%20introduced%20as,and%20their%20possible%20effects%20on%20people%20 and%20systems.

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Table 52: NOAA Radio Blackouts Space Weather Scale and Potential Effects125F 126
126 National Oceanic and Atmospheric Administration. (2011, April 7). Space Weather Scales. https://swpc-drupal.woc.noaa.gov/noaa-scalesexplanation#:~:text=The%20NOAA%20Space%20Weather%20Scales%20were%20introduced%20as,and%20their%20possible%20effects%20on%20people%20 and%20systems.

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9.2 Hazard Profile

9.2.1 Past Events
The National Centers for Environmental Information (NCEI) receives storm data from the National Weather Service (NWS) that is then compiled into a Storm Events Database. NWS receives their information from a variety of sources, which include but are not limited to, county, City, and federal emergency management officials; local law enforcement officials; SkyWarn spotters; NWS damage surveys; newspaper clipping services; the insurance industry; and the general public, among others.

Please note that the NWS does not guarantee the accuracy, validity, or completeness of the event data in the Storm Events Database.

The Storm Events Database has a record of inclement weather events that occurred in the OA during the last twenty-one years (see Table 53). These events include heavy rain/precipitation, excessive heat or cold, and high winds. In total, inclement weather has caused an estimated $24,152,120 in property damage in the OA. $10,025,020 was from Heavy Precipitation Events Heavy Precipitation
11/30/2012 A series of storms brough strong winds, heavy rainfall and flooding to the region and reported of 13,800 power outages in the Bay Area.
12/3/2014 Rain, wind, some flooding issues and downed trees and power lines were reported. 12/11/2014 An atmospheric river brought heavy rain and gusty winds. Rainfall rates of 1.5 – 2 inches/hour were reported. Many locations around the Bay Area had urban flooding of streets and highways and flooding of creeks.
2/9/2015 Heavy rain, gusty winds, and damage to trees and power lines along with some minor flooding of urban areas occurred.
1/8/2017 Potent atmospheric river brought heavy rain, strong southerly winds, and storm surge issues.

Dec 27, 2022 – Jan. 31, 2023. A series of heavy rainstorms affected multiple counties, prompting emergency declarations. Road closures occurred in Gilroy, including closer of southbound Hwy 101.

Other road closures occurred in San Jose and other parts of the valley due to flooding. Heavy rain contributed to a landslide that temporarily blocked Hwy 17 at Glenwood Drive in Los Gatos. On January 13, 2023, Santa Clara County issued evacuation warnings for watershed areas of the Uvas Reservoir, Pacheo Pass River bases, and Highway 101 and Bolsa Road due to continued weather and flooding concerns.

Additional examples of heavy rain contributing to landslides can be found in Section 14.2.1.

Table 53: 2001–2022 Heavy Rain and Hail Events
Dates of Event Event Type Location
12/15/2002 Heavy Rain Santa Clara County/Los Gatos
12/15/2002 Heavy Rain Santa Clara County/Saratoga

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Dates of Event Event Type Location
11/30/2012 Heavy Rain Santa Clara County
11/30/2012 Heavy Rain Santa Clara County
10/10/2012 Hail Santa Clara County/Gilroy
10/10/2012 Hail Santa Clara County/Gilroy
2/9/2014 Heavy Rain Santa Clara County
12/3/2014 Heavy Rain Santa Clara County/Saratoga
12/11/2014 Heavy Rain Santa Clara County
2/9/2015 Heavy Rain Santa Clara County
2/9/2015 Heavy Rain Santa Clara County
1/8/2017 Heavy Rain Santa Clara County/Morgan
Hill
1/19/2017 Hail Santa Clara County/Los Gatos
1/19/2017 Hail Santa Clara County
1/20/2017 Hail Santa Clara County/Los Gatos
2/17/2017 Heavy Rain Santa Clara County
3/5/2017 Hail Santa Clara County/Los Gatos
1/19/2018 Hail Santa Clara County
1/25/2018 Hail Santa Clara County/San Jose
1/25/2018 Hail Santa Clara County/Gilroy
1/25/2018 Hail Santa Clara County/Gilroy
1/25/2018 Hail Santa Clara County/Morgan
Hill
2/26/2018 Hail Santa Clara County/Gilroy
3/2/2018 Hail Santa Clara County/San Jose
3/17/2018 Hail Santa Clara County/Sunnyvale
4/16/2018 Hail Santa Clara County/San Jose
4/16/2018 Hail Santa Clara County
2/15/2019 Hail Santa Clara County
3/10/2019 Hail Santa Clara County/San Jose

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Dates of Event Event Type Location
3/10/2019 Hail Santa Clara County/San Jose
3/10/2019 Hail Santa Clara County
1/16/2020 Hail Santa Clara County
1/16/2020 Hail Santa Clara County
3/17/2020 Hail Santa Clara County
3/25/2020 Hail Santa Clara County/Los Gatos
3/25/2020 Hail Santa Clara County/Palo Alto
3/25/2020 Hail Santa Clara County/Mountain
View
3/25/2020 Hail Santa Clara County/Mountain
View
3/25/2020 Hail Santa Clara County/Gilroy
3/25/2020 Hail Santa Clara County/Sunnyvale
3/25/2020 Hail Santa Clara County/Gilroy
3/25/2020 Hail Santa Clara County/Santa
Clara
4/6/2020 Hail Santa Clara County
3/10/2021 Hail Santa Clara County/San Jose
Extreme Heat or Cold
The NCEI reports 14 deaths in Santa Clara County since 2002 as a direct result of cold and wind chill.

Seven deaths and 61 injuries have been directly attributed to heat. • NCEI reports that excessive heat led to rolling blackouts in the Bay Area on 8/14/2020 • On 8/16/2020, extreme heat contributed to 464 EMS calls across Santa Clara County. • NCEI documents the use of cooling centers to counter the effects of extreme heat in Santa Clara on 5/17/2009 and 9/4/2022.
• On 1/6/2007, the NCEI records that freezing temperatures in Santa Clara Valley fell into the lower 20s, causing $50,000 in crop damage.
• On 12/8/2009, Light rail trains were delayed and Highway 101 to Interstate 280 in San Jose were closed due to severe ice on the roadway. Flights from San Jose International Airport were delayed because some airlines do not have de-icing equipment. Ice also contributed to a vehicle accident.

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Table 54: 2001–2022 Extreme Temperature Events
Dates of Event Event Type Location
7/20/2006 Heat Santa Clara Valley Including
San Jose
7/21/2006 Heat East Bay Hills and the Diablo
Range (Zone)
7/22/2006 Heat San Francisco Bay Shoreline
(Zone)
7/22/2006 Heat Santa Cruz Mountains (Zone)
5/17/2009 Heat Santa Clara Valley Including
San Jose
5/17/2009 Heat San Francisco Bay Shoreline
(Zone)
5/17/2009 Heat East Bay Hills and the Diablo
Range (Zone)
5/17/2009 Heat Santa Cruz Mountains (Zone)
6/19/2017 Heat Santa Clara Valley Including
San Jose
12/25/2018 Cold/Wind Chill Santa Clara Valley including San Jose
1/1/2019 Cold/Wind Chill Santa Clara Valley including
San Jose
11/27/2019 Cold/Wind Chill Santa Clara Valley including San Jose
11/28/2019 Cold/Wind Chill Santa Clara Valley including San Jose
11/29/2019 Cold/Wind Chill Santa Clara Valley including San Jose
6/10/2019 Heat Santa Clara Valley Including
San Jose
6/10/2019 Excessive Heat San Francisco Bay Shoreline
(Zone)
8/14/2020 Excessive Heat San Francisco Bay Shoreline
(Zone)
8/16/2020 Excessive Heat Santa Clara Valley Including
San Jose
9/6/2020 Excessive Heat Santa Clara Valley Including
San Jose
9/7/2020 Excessive Heat San Francisco Bay Shoreline
(Zone)
6/17/2021 Heat Santa Clara Valley Including
San Jose
6/17/2021 Heat Santa Clara Valley Including
San Jose

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Dates of Event Event Type Location
7/11/2021 Excessive Heat East Bay Hills and the Diablo
Range (Zone)
6/10/2022 Heat Santa Clara Valley Including
San Jose
6/21/2022 Heat San Francisco Bay Shoreline
(Zone)
6/21/2022 Heat San Francisco Bay Shoreline
(Zone)
6/21/2022 Heat Santa Clara Valley Including
San Jose
9/4/2022 Heat Santa Clara Valley Including
San Jose
9/4/2022 Heat San Francisco Bay Shoreline
(Zone)
9/4/2022 Heat Santa Clara Valley Including
San Jose
9/4/2022 Heat Santa Clara Valley Including
San Jose
9/5/2022 Heat San Francisco Bay Shoreline
(Zone)
9/5/2022 Heat Santa Clara Valley Including
San Jose
9/6/2022 Heat San Francisco Bay Shoreline
(Zone)
9/6/2022 Heat Santa Clara Valley Including
San Jose
9/8/2022 Heat Santa Clara Valley Including
San Jose
High Wind
• In addition, the NOAA/NCEI database reports 494 high wind events that have occurred in the OA since 2005. This is the most common inclement weather hazard type to affect the OA, and these events have caused an estimated $7,406,100 in property damage since the first recorded incident in 2005.
• On 1/19/2010-1/22/2000, the NCEI records strong winds that affected the Bay Area. Winds knocked two trees down along East Santa Clara Street in San Jose and around 10,000 customers lost power in the San Jose area. Additional incidents of trees and limbs falling and causing damage were reported. These reports include damage to utilities such as telephone poles and power transformers, damage caused to vehicles, partially blocked roadways, or injured people. Specific impacts were recorded in San Jose, Los Gatos, and Milpitas.

Table 55:2002-2022 High Wind Events

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Years Number of Wind Events
2005 6
2006 11
2008 16
2009 18
2010 21
2011 15
2012 14
2013 23
2014 32
2015 15
2016 3
2017 51
2018 26
2019 92
2020 52
2021 61
2022 9
Although rare, Santa Clara County has also experienced tornados, which have caused a total of $6,721,000 in damage.

Table 56: 1951–2022 Tornado Events
Date Event Type Location
1/11/1951 F2 Tornado Santa Clara County
12/8/1997 F0 Tornado San Jose
2/6/1998 F0 Tornado Sunnyvale
5/5/1998 F1 Tornado Los Altos
5/5/1998 F2 Tornado Sunnyvale
4/14/2007 EF0 Tornado Gilroy

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Space Weather
Space weather monitoring is relatively new, and there is limited data available regarding historical occurrences. However, we know that space weather has impacted the OA and is likely to impact the OA in the future.

9.2.2 Location
Heavy precipitation/Rain, extreme heat or extreme cold, high winds, and even space weather can occur anywhere within the OA. The extent is highly variable. Given their widespread nature, these events have the potential to impact large areas simultaneously. Historical records show that these events can happen in one isolated part of the OA, or in the entirety of the planning area. Therefore, inclement weather events are not confined to any geographical barrier and may impact all parts of the OA.

9.2.3 Frequency
Several types of inclement weather have shown an increasing number of events in recent years. This represents a trend that due to factors such as climate change it is likely that inclement weather events will become more frequent over time. Based on the frequency of historic events, inclement weather events can be expected to occur multiple times annually.

Heavy Precipitation: According to the historical events reported by the NCEI database, 44 heavy precipitation events have occurred in the last twenty-one years. Of these 44 events, 33 incidents have occurred in the last five years alone.

Probability in OA: Highly Likely
Extreme Temperature: 33 extreme temperature events were recorded in the NCEI database since 2002. 24 of those have occurred since 2017.

Probability in OA: Highly Likely
High Wind: 470 high wind events have occurred in the OA since 2005. Wind speeds in these events have ranged from 9 to 96 knots.

Probability in OA: Highly Likely
Space Weather: Data was not available to estimate the frequency of space weather events.

Probability in OA: Likely

9.2.4 Severity
Severity will depend on the extent of each event and can range from mild to severe. Inclement weather can cause disruption to critical facilities and extensive damage to property and infrastructure. The NCEI database reports a total of $24,152,120 in property damage from these events in some of the most severe cases, not including space weather.

The levels of severity related to space weather are best described in Table 50, Table 51, and Table 52.

The level of severity can range from minor to extreme and will mostly impact the OA’s technological, communication, and power grid systems.

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9.2.5 Warning Time
The National Weather Service provides forecasting and prediction services for a variety of inclement weather events and maintains an established process for issuing advisories, watches and warnings for each. The amount of warning time varies on the type of weather event. 126 F 127
Heavy Precipitation: warning times for significant weather events may vary widely. Initial storm advisories can have a lead time of 36-48 hours. More extreme events like thunderstorms, hail, or other severe weather may have warning of an hour or less.

Extreme Temperature: Advisories regarding extremes in heat or cold can be issued with 0-36 hours of lead time.

High Wind: Wind advisories can have a lead time of 12 to 36 hours.

Space Weather: Space weather prediction services are provided by NOAA’s Space Weather Prediction Center. The SWPC draws on various data sources to provide forecasts, watches, warning and alerts with a possible lead time of hours to days of possible space weather activity.127F 128 Lead time varies from hours to
days.

9.3 Cascading Impacts
While inclement weather is the most common hazard to occur in the OA, it is important to note the potential cascading impacts of these events.

Heavy precipitation can lead to significant flooding, also contributing to landslides and mudslides, posing serious threats to human lives, property, infrastructure and ecosystems. Flooding and other cascading impacts of heavy rain can interrupt transportation, utility services, or other emergency services.

Extreme temperatures, whether excessively hot or cold, will have impacts on human health, potentially leading to heatstroke, dehydration, and cold-related illnesses. Additionally, extreme temperatures can strain energy resources and infrastructure, increasing the risk of blackouts and disruption of critical services and infrastructure.

High winds have historically caused damage across the OA. They can damage or disrupt essential functions and interrupt service from energy and communication systems.

Space weather events, such as solar flares and geomagnetic storms can be significant and pose substantial risks to modern technological systems and critical infrastructure. Space weather can disrupt satellite communications, GPS, and aviation systems, affecting various sectors, including telecommunications, transportation, and emergency services.

9.4 Exposure

9.4.1 Population
Because of the unconfined and variable nature of inclement weather, the entire population is considered to be exposed. Heavy rain, hail, lightning, high winds, and extreme temperatures all have the potential to harm the health of or injure people within the OA.
127 https://www.weather.gov/safety/
128 Space Weather Watc https://www.weather.gov/safety/space-wwhes, Warnings and Alerts

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Table 57: Population by Jurisdiction
Jurisdiction 2022
City of Campbell 42,833
City of Cupertino 59,610
City of Gilroy 59,269
City of Los Altos 31,526
Town of Los Altos Hills 8,400
Town of Los Gatos 33,062
City of Milpitas 80,839
City of Monte Sereno 3,488
City of Morgan Hill 46,451
City of Mountain View 83,864
City of Palo Alto 67,473
City of San José 976,482
City of Santa Clara 130,127
City of Saratoga 30,667
City of Sunnyvale 156,234
Unincorporated County 84,458
Total 1,894,783

9.4.2 Property
There are 535,391 buildings in the OA, with a total replacement value of $381 billion. All of these buildings exist in an area susceptible to inclement weather; however, dollar loss estimates for specific building occupancy types or geographic areas are not available. Although inclement weather events are the most frequent hazard in the OA, historic dollar losses have been comparatively moderate.

9.4.3 Critical Facilities and Infrastructure
All critical facilities in the OA are potential exposed to inclement weather. Facilities may be damaged directly by high winds, hail, or by flooding that results from heavy rain. Water, electric, fuel, transportation, and communication services could be disrupted by damage caused by heavy precipitation, high winds, or space weather. Extreme temperature may also disrupt services or strain energy systems.

9.5 Vulnerability
Changes in conditions: Increase in vulnerability
 A review of past events indicates that an increasing number of inclement weather events per year for heavy rain, extreme heat, and high winds.

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 CMRA indicates a trend in increasing number of extreme heat days each year and the number of consecutive hot days. Climate change will continue to increase the amount of very hot days and impacts to residents will increase as a result.
 Climate change affects the frequency and intensity of storms, which contributes to the potential of damaging inclement weather events such as heavy rain, hail, and high wind across the OA.  Overall population and building growth are slow in the OA, and are not expected to be a significant factor in increased vulnerability. Currently the increase in vulnerability appears to be driven more by an increased number of events than changes in development. However, continued monitoring of demographic shifts, new insights regarding the effects of climate change, economic changes that may impact building and other development, and aging of building stock and infrastructure should continue to receive consideration on potential weather impacts.

Individual jurisdictional annexes may note localized growth at a smaller scale.

9.5.1 Population
Because of the unpredictable nature of when and where significant weather events can occur, and variable intensity of these events, all of the OAs population of 1,894,783 residents are potentially vulnerable to impacts of inclement weather. The OA has a population of nearly 10,000 people that are homeless, according to the 2023 Santa Clara Point-In-Time report. This population is especially vulnerable to the impacts of inclement weather, especially with extreme heat and cold events, which can be detrimental to human health. Only 25% of individuals experiencing homelessness are sheltered, and the other 75% may be exposed to the elements and inclement weather events. NCEI has documented cases of illness or death in Santa Clara County related to extreme heat or cold.

All other vulnerable populations such as those in poverty, the elderly, and children can be negatively impacted by inclement weather events. Hazus 6.0 demographic data indicates that 260,705 persons or

13.5 percent of the population in the OA are over 64 years old. Older persons are particularly at risk to health problems caused by extreme heat. 422,719 persons or 21.8 percent of the population within the OA under 18 years of age. It is estimated that 2.45 percent of the people within the OA are economically disadvantaged, defined as having household incomes of $20,000 or less.

People with disabilities, communities of color, persons with limited English proficiency, housing condition, health care access and education are additional factors that affect vulnerability to severe weather hazards identified in the Silicon Valley 2.0 hazard fact sheet for extreme heat. Outdoor workers and unhoused residents are among the population most at risk. According to the Silicon Valley 2.0 report, 62% of the total County population is currently exposed to extreme heat conditions and 42% of those exposed have moderate to high social vulnerability. Approximately 60,000 people within moderate socially vulnerable communities in South County jurisdictions, such as Morgan Hill and Gilroy, could be exposed to frequent extreme heat events.

All business, schools, and government systems reliant on technology are vulnerable to the impacts of space weather. As space weather has the potential to disrupt the OA’s power and communication systems, any entity reliant on technology may experience more severe impacts.

9.5.2 Property, Critical Facilities, Infrastructure
Hazus modeling is not available to quantify potential damage to property, critical facilities, or infrastructure in the OA. Physical damage and service disruption are variable depending on the size and severity of the weather event.

Although the exact location and intensity of weather events makes it difficult to project exactly what physical assets may be at risk, possible impacts might include:

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Heavy Rain
• Localized pooling of water on roadways has occurred during or following past heavy rain events.

Flooding in early 2023 lead to closures of major transportation routes, including Hwy 101 in Gilroy. Vehicles may lose traction or may be unable to safely traverse some roadways. Impacts to roadways may cause delays to emergency responders.
• Heavy rain has contributed to landslides and other slope failures that have blocked or damaged roadways.
• Pedestrian travel is particularly difficult during a severe weather event. Those who rely on public transportation may have difficulty reaching transit points or difficulty finding shelter if service is interrupted
• Heavy rain has caused localized flooding and subsequent water damage to nearby structures.

Flooding from heavy rain can damage residences, commercial, industrial, or other building types.

High Wind
• Above ground utilities such as communication towers, telephone lines and power lines are vulnerable to damage from high winds. High winds have caused trees to fall which have damaged power lines and transformers, disrupting power service to large areas. • Critical facilities may also lose power if high winds damage power distribution systems and may need to rely on back-up power systems.
• High winds can damage roofs or windows to homes and businesses or other critical facilities.

Winds can also lead to fallen trees which may damage nearby buildings or sidewalks. • Outdoor events such as sporting activities, farmers markets, and community festivals can be disrupted, and participants may have difficulty seeking shelter from a fast-moving storm.

Extreme Heat
• Extreme heat may lead to increased demand on energy systems which may strain their ability provide adequate cooling to facilities and increases potential for power outages. Rolling brownouts have occurred in the Bay Area during past extreme heat events. • High temperatures can cause pavement to soften and expand which can cause rutting, potholes, or other damage to streets.
• Extreme heat has had serious health consequences for people who are unhoused or for outdoor workers.

Extreme Cold
• Extreme cold is less common in the OA, but results in difficult travel if combined with precipitation that may lead to icy roadways, airport runways, and other transportation systems. • NCEI records have documented impacts to highways, airports, and mass transit systems due to icy conditions during period of extreme cold.
• Dangerous travel conditions can lead to damage from collisions, personal injury, or economic disruption.

9.5.3 Environment
Cascading effects of heavy rain could be damaging to the environment, such as erosion caused by increased runoff or flooding, or to systems damage from landslides. Hail can cause extensive damage to plants. High winds can break tree branches or cause other damage to plant life or animal habitat.

9.5.4 Economy
Inclement weather events can disrupt the economy of the OA. Economic impact will largely be associated with the disruption of transportation, power, gas, and telecommunication services caused by high winds, or associated with flooding caused by heavy precipitation. Events severe enough to cause structural damage can also cause business interruptions. The economic sectors affected may vary significantly depending on the extent and severity of the event.

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9.6 Future Trends in Development, Scenario, Issues
Impacts from inclement weather pose a real threat to physical, social and economic well-being in the OA.

Multiple events can be expected to affect the OA every year, with variable severity. OA residents can use weather advisories to prepare themselves for inclement weather events, but sometimes severe events have limited warning time. Inclement weather has the potential to cause cascading impacts and can damage multiple systems in both limited and widespread areas. Although there have been small decreases in population in recent years, Santa Clara County has experienced significant growth in the past. New development may affect drainage patterns and change impacts from heavy rain. An increase in population coincides with an increased number of people at risk to weather events. As discussed further in Section 11: Climate Change, impacts of severe weather are projected to intensify due to climate change.

9.7 Issues
 Inclement weather is inherently uncertain. Conditions can change rapidly, and the severity and exact locations of an event are highly variable.
 The variable nature of inclement weather makes it difficult to identify specific locations, structures, or systems that might be more likely to be damaged in an event. This makes it difficult to identify priorities or areas for risk reduction projects.
 People may not heed weather warnings.
 Heavy rain events may result in ponding or localized flooding in low-lying areas.  Heavy rain may result in inland stormwater flooding after stormwater management systems are overwhelmed.
 Inclement weather can cause secondary hazards such as flooding, landslides, mudslides, and disruption of systems or infrastructure.
 Inclement weather events are directly related to climate change; however, climate change impacts still are poorly understood. Average temperatures are expected to increase and changes in precipitation patterns are anticipated, but it is not yet known how that will impact local weather patterns. Impacts of inclement weather events are anticipated to become more severe.

9.8 Consequence Analysis
Inclement weather events occur frequently, and these events are likely to increase in frequency over time.

They may cause a wide range of impacts, which vary greatly depending on the level of severity and extent for each event. The information in Table 58 provides the consequence analysis of the potential for detrimental impacts of inclement weather done for accreditation with the Emergency Management Accreditation Program (EMAP).

Table 58: EMAP Consequence Analysis Inclement Weather
Subject Ranking Impacts/Inclement Weather
Health and Safety of
Public in the Area of the
Incident
Severe Impact of the immediate area could be severe for affected areas and moderate to light for other less
affected areas.

Responders Moderate Impact to responders could be severe for unprotected personnel and moderate to light for prepared personnel.

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Subject Ranking Impacts/Inclement Weather
Continuity of Operations
(including continued
delivery of services)
Moderate There is a moderate expectation to execute the COOP, though a severe level of impact can be expected for the full extent of an inclement weather event.

Property, Facilities, and
Infrastructure
Minimal to
Severe
There is potential for localized impact to facilities and infrastructure in the incident area, which can range from minimal to severe depending on the extent of the
incident.

Delivery of Services Minimal to
Severe
Delivery of services could be affected if there is any
disruption to the roads and/or utilities due to damages sustained.

Environment Moderate to
Severe
Greatest impact will be to trees, bushes, foliage, crops, and wildlife, which could be severe.

Economic Conditions Minimal to
Severe
Impacts to the economy will greatly depend on the
severity of the inclement weather event, longevity of the storm, and any damages sustained such as utilities and
roads. Public Confidence in the
Government
Minimal to
Severe
Response and recovery will be in question if not timely and effective.

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10 Drought
Definitions
 Meteorological Drought: Occurs when rainfall has been deficient for an extended period.  Hydrological Drought: Occurs when rainfall deficits impact the water supply available from streams, reservoirs, lakes, and groundwater.
 Agricultural Drought: Occurs when factors such as rainfall deficits, soil water deficits, reduced groundwater, or low reservoir levels for irrigation result in impacts on agriculture.  Socioeconomic Drought: Occurs when diminished water supply reduces the supply of economic goods such as fruits, vegetables, grains, or meat.
 Ecological Drought: Occurs when a prolonged and widespread deficit in naturally available water supplies—including changes in natural and managed hydrology—creates multiple stresses across ecosystems.

10.1 General Background
Drought is a significant decrease in water supply relative to what is “normal” in a given location. A normal phase in the climate cycle of most geographical regions, drought originates from a deficiency of precipitation over an extended period, usually a season or more. This leads to a water shortage for some activity, group, or environmental sector.

Determination of when drought begins is based on impacts on water users and assessments of the available water supply, including water stored in surface reservoirs or groundwater basins. Different water agencies have different criteria for defining drought. Some issue drought watch or drought warning announcements. The California Water Code does not include a statutory definition of drought; however, analysis of the code indicates that legal matters most frequently focus on drought conditions during times of water shortages.

10.1.1 Monitoring and Categorizing Drought
Drought monitoring at the national, regional, and local levels is an integral part of drought early warning, planning, and mitigation.128 F
129 Nationally, agencies involved in this effort include the National Oceanic and Atmospheric Administration, National Integrated Drought Information System which produces the U.S.

Drought Monitor, and the National Drought Mitigation Center at the University of Nebraska-Lincoln.

In California, drought is addressed by the California Department of Water Resources (DWR).

The National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration (NOAA) has developed several indices to measure drought impacts and severity and to map their extent and locations:
 The Palmer Crop Moisture Index measures short-term drought weekly to quantify drought’s impacts on agriculture during the growing season.
129 National Oceanic and Atmospheric Administration. (n.d.). Monitoring Drought. https://www.drought.gov/what-isdrought/monitoring-drought

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 The Palmer Drought Severity Index is based on long-term weather patterns. Long-term drought is cumulative, so the intensity of drought during a given month depends on current weather plus the cumulative weather of previous months. The Palmer Drought Index responds rapidly as weather patterns change quickly.
 The Palmer Z Index measures short-term drought on a monthly scale.  The hydrological impacts of drought (e.g., reservoir levels, groundwater levels, etc.) take longer to develop and it takes longer to recover from them. The Palmer Hydrological Drought Index is a long-term index to quantify hydrology effects. The Palmer Hydrological Drought Index responds more slowly to changing conditions than the Palmer Drought Index.  The Standardized Precipitation Index considers only precipitation. In the Standardized Precipitation Index, an index of zero indicates the median precipitation amount; the index is negative for drought and positive for wet conditions. The Standardized Precipitation Index is computed for time scales ranging from one month to 24 months.

The following graphics show the Palmer Drought Index and Palmer Hydrological Drought Index for California Climate Division 4, of which Santa Clara County is a part, from January 1, 2005, to May 20, 2023. Near normal conditions are indicated by -1.9 to +1.9. Drought conditions are indicated by -2.0 to -

4.0 or less and wet conditions are indicated by +2.0 to +4.0 or above.

Figure 45: Palmer Drought Index from January 1, 2005, to May 20, 2023129F 130
Figure 46: Palmer Hydrological Drought Index from January 1, 2005, to May 20, 2023130F 131
130 National Centers for Environmental Information. (2023, May). Weekly Palmer Drought Indices Divisional Time Series. https://www.ncei.noaa.gov/access/monitoring/weekly-palmers/time-series/0404 131 National Centers for Environmental Information. (2023, February). North American Drought Monitor. https://www.ncei.noaa.gov/access/monitoring/nadm/indices/spi/div

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U.S. Drought Monitor
The U.S. Drought Monitor (USDM) is a map that is updated weekly to show the location and intensity of drought across the country. The USDM uses a five-category system.13F 132
 D0: Abnormally Dry
▪ Short-term dryness slowing planting and growth of crops ▪ Some lingering water deficits
▪ Pastures or crops not fully recovered
 D1: Moderate Drought
▪ Some damage to crops and pastures
▪ Some water shortages are developing
▪ Voluntary water-use restrictions requested
 D2: Severe Drought
▪ Crop or pasture loss likely
▪ Water shortages are common
▪ Water restrictions imposed
 D3: Extreme Drought
▪ Major crop/pasture losses
▪ Widespread water shortages or restrictions
 D4: Exceptional Drought
▪ Exceptional and widespread crop/pasture losses
▪ Shortages of water creating water emergencies

10.1.2 Normal Precipitation in California
Most of California’s precipitation comes from storms moving across the Pacific Ocean. Extremely dry and extremely wet years have become more common in California.132F 133 On average, 75 percent of California’s
annual precipitation occurs between November and March, with 50 percent occurring between December and February. A persistent Pacific high-pressure zone over California in mid-winter signals a tendency for a dry water year. A typical water year produces about 100 inches of rainfall over the North Coast, 50 inches of precipitation (combination of rain and snow) over the Northern Sierra, and 15 inches in Santa Clara County. In extremely dry years, these annual totals can fall to as little as one half, or even one third of these amounts.
132 National Integrated Drought Information System. (n.d.). U.S. Drought Monitor (USDM). https://www.drought.gov/data-maps-tools/us-droughtmonitor#:~:text=Thepercent20U.S.percent20Droughtpercent20Monitorpercent20percent28USDMpercent29percent20 ispercent20apercent20map,Severepercent20percent28D2percent29percent2Cpercent20Extremepercent20percent28 D3percent29percent20andpercent20Exceptionalpercent20percent28D4percent29percent20Drought. 133 Office of Environmental Health Hazard Assessment. (2018). Precipitation. https://oehha.ca.gov/media/epic/downloads/09precipitation_19dec2018.pdf#:~:text=Extremelypercent20drypercent20 andpercent20extremelypercent20wetpercent20yearspercent20havepercent20become,thatpercent20providepercent2 0mostpercent20ofpercent20thepercent20statepercentE2percent80percent99spercent20waterpercent20supplies.

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As the winter months have become warmer in recent years, more precipitation has been falling as rain instead of snow over the watersheds that provide most of the state’s water supplies. With climate change, more intense dry periods under warmer conditions are anticipated, leading to extended, more frequent drought in California. A higher proportion of precipitation falling as rain instead of snow and an increase in the duration, frequency, and intensity of warm, wet storms are also projected. This can result in greater flooding, and force reservoirs to release more water early in the spring, which means less water will be available for agriculture and municipal uses in the summer and fall.13F 134
The Sierra Nevada snowpack serves as the primary agent for replenishing water in the San Francisco Bay area, including Santa Clara County, and for much of the State of California. A reduction in spring snowpack runoff, whether due to drier winters or to increasing temperatures leading to more rain than snow, can increase the risk of summer or fall water shortages throughout the region.

Increases in temperature are already causing decreases in snowpack. The mountain snowpack provides as much as a third of California’s water supply by accumulating snow during our wet winters and releasing it slowly during our dry springs and summers. Warmer temperatures will melt the snow faster and earlier, making it more difficult to store and use throughout the dry season. The DWR Climate Change Team expects that by the end of this century, California’s Sierra Nevada snowpack is projected to experience a 48–65 percent loss from the historical April 1 average of 66.5 inches.134F 135

10.1.3 Water Supply Strategy
The Bay Area Water Supply Conservation Agency (BAWSCA) is the main water provider for much of the Bay Area, allowing Santa Clara Valley Water District (SCVWD) to manage the continual water supply necessary to maintain health, safety, and economic wellbeing of residents, businesses, and community organizations. BAWSCA developed a two-phase, long-term water supply strategy for customers throughout the Bay Area, as outlined in the 2015 Long-Term Reliable Water Supply Strategy Phase II Final Report.135 F
136 Purposes of its strategy are as follows:
 Quantifying water supply reliability needs of BAWSCA member agencies through 2040.  Identifying water supply management programs or programs that can be developed to meet those regional water reliability needs.
 Developing an implementation plan for the water supply strategy.

This strategy recognized that drought-year shortfalls could be significant but determined that normalyear water supply would be adequate through at least 2040. Dry years could result in system-wide cutbacks of up to 20 percent, but 10 to 15 percent is the more consistent standard. BAWSCA noted that the impacts of water shortages would be regional and could lead to secondary detrimental economic effects. To address this concern, the strategy focused on identifying options for filling all or part of the drought-year supply shortfall and investigating and potentially implementing actions that seem most beneficial.136F
137
134 Office of Environmental Health Hazard Assessment. (2018). Precipitation. https://oehha.ca.gov/media/epic/downloads/09precipitation_19dec2018.pdf#:~:text=Extremelypercent20drypercent20 andpercent20extremelypercent20wetpercent20yearspercent20havepercent20become,thatpercent20providepercent2 0mostpercent20ofpercent20thepercent20statepercentE2percent80percent99spercent20waterpercent20supplies. 135 California Department of Water Resources. (n.d.). Climate Change and Water. https://water.ca.gov/Programs/AllPrograms/Climate-Change-Program/Climate-Change-and-Water 136 Bay Area Water Supply Conservation Agency. (2015 February). Long-Term Reliable Water Supply Strategy. https://bawsca.org/water/reliability/strategy
137 Bay Area Water Supply & Conservation Agency. (n.d.). Water Supply & System. https://bawsca.org/water/supply

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BAWSCA also developed a Water Conservation Implementation Plan,137F 138 focusing on the following
objectives:
 Help BAWSCA member agencies evaluate potential water savings and cost-effectiveness associated with implementing additional water conservation measures beyond their commitments of 2004.
 Determine potential water savings in 2018 and 2030 based on a selected range of new conservation measures and the 2004 water conservation commitments.  Determine BAWSCA’s role in helping member agencies achieve individual water conservation goals.
 Develop a coordinated regional plan for water conservation implementation measures to serve as a guideline for member agencies.

In the Santa Clara County OA, the following districts and cities are members of BAWSCA: SCVWD, Milpitas, Mountain View, Palo Alto, San José, City of Santa Clara, Sunnyvale, Purissma Hills Water District, and Stanford University.138F
139
The SCVWD is the wholesale water and groundwater management agency throughout Santa Clara County, relying on local retailers (municipalities and private companies) to deliver water throughout the County.139F
140 The following are the retailer water providers for each municipal planning partner:
 Campbell: San José Water Company
 Cupertino: San José Water Company and California Water Service Company  Gilroy: Gilroy Public Works Department
 Los Altos: California Water Service Company
 Los Altos Hills: Purissima Hills Water District and California Water Service Company  Los Gatos: San José Water Company
 Milpitas: City of Milpitas Community Services
 Monte Sereno: San José Water Company
 Morgan Hill: City of Morgan Hill
 Mountain View: City of Mountain View Public Works
 Palo Alto: City of Palo Alto Utilities Department
 San José: San José Water Company, Great Oaks Water Company, and San José Municipal Water System
 Santa Clara City: City of Santa Clara Water Department  Saratoga: San José Water Company
138 Bay Area Water Supply & Conservation Agency. (n.d.). Conservation Implementation Plan. https://bawsca.org/conserve/reports/plan#:~:text=Thepercent20specificpercent20objectivespercent20ofpercent20thep ercent20WCIPpercent20arepercent20as,beyondpercent20whatpercent20theypercent20hadpercent20committedperc ent20topercent20inpercent202004.
139 Bay Area Water Supply & Conservation Agency. (2020). Member Agency Map. https://bawsca.org/members/map 140 Santa Clara Valley Water District. (2021). Groundwater Management Plan. https://s3.us-west2.amazonaws.com/assets.valleywater.org/2021_GWMP_web_version.pdf

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 Sunnyvale: City of Sunnyvale Public Works Department and California Water Service Company
The SCVWD has its own water supply strategy outlined in the SCVWD Water Supply Master Plan 2040.140F 141
The Water Master Plan 2040 outlines a water supply strategy with three key elements:
 Secure existing supplies and facilities.
 Optimize the use of existing supplies and facilities.  Expand water use efficiency efforts.

Some County residents have domestic wells on their property. The North Central Regional Office of California DWR monitors wells for Santa Clara County to help protect groundwater quality.14F 142 Under
Ordinance 90-1, as of July 1, 2013, a person must obtain a permit from SCVWD to perform any well activities. In response to extreme and expanding drought conditions, as those existing on March 28, 2022, the state can prohibit Valley Water and other well permitting agencies from issuing a construction permit for a new groundwater well.142F
143

10.1.4 Water Supply Infrastructure
Figure 46 shows the SCVWD water supply system. Santa Clara County receives 50 percent of its water supply from the San Francisco Bay-Delta watershed. Of this water, 40 percent comes directly through the Delta watershed or water conveyance systems and 10 percent is from the Hetch-Hetchy System. Another 30 percent of the County’s supply is local, from natural groundwater, reservoirs to groundwater, and reservoirs to drinking water treatment plans. Five percent is recycled water, primarily used for irrigation, industry, and agriculture. A 15 percent water-use reduction by the community is required to reach the needed water supply total.143F
144
141 Santa Clara Valley Water District. (2019, November). Water Supply Master Plan 2040. https://www.valleywater.org/sites/default/files/Waterpercent20Supplypercent20Masterpercent20Planpercent202040_

11.01.2019_v2.pdf
142 California Department of Water Resources. (n.d.). Technical Assistance. https://water.ca.gov/Programs/Integrated-Regional-Water-Management/Technical-Assistance 143 Santa Clara Valley Water District. (n.d.). Well Permits and Inspections. https://www.valleywater.org/contractors/doing-businesses-with-the-district/wells-well-owners/well-permits-andinspections 144 Santa Clara Valley Water District. (n.d.). Where Your Water Comes From. https://www.valleywater.org/yourwater/where-your-water-comes

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Figure 47: Santa Clara Valley Water District System Water Supply14F 145
The Hetch-Hetchy Water System was approved in 1913 under the Raker Act, which allowed use of federal lands to build that water system. The water system was constructed by San Francisco over the next 20 years, with first delivery of water in 1934. Although the system is owned by San Francisco, it was designed from the beginning to serve as a regional water supply system.145 F 146 Figure 47 shows the HetchHetchy Water System.
145 Santa Clara Valley Water District. (n.d.). Where Your Water Comes From. https://www.valleywater.org/yourwater/where-your-water-comes 146 Bay Area Water Supply and Conservation Agency. (n.d.). Hetch Hetchy System. https://bawsca.org/water/supply/hetchhetchy

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Figure 48: Hetch Hetchy Water System146F
147

10.2 Hazard Profile
Droughts originate from a deficiency of precipitation resulting from an unusual weather pattern. Such patterns can be short-term, lasting for a few weeks or months, or long-term, lasting for many months or for years. It is possible for a region to experience a long-term circulation pattern that produces drought, and to have short-term changes in this long-term pattern that result in short-term wet spells. Likewise, it is possible for a long-term wet circulation pattern to be interrupted by short-term weather spells that result in short-term drought. Droughts typically occur after 2 or 3 years of below-average rainfall during the period from November to March, when about 75 percent of California’s average annual precipitation falls.

10.2.1 Past Events
California is no stranger to drought; it is a recurring feature of our climate.147F 148 The DWR has state
hydrologic data from as far back as the early 1900s which indicate occurrences of multi-year droughts from 1912 to 1913, 1918 to 1920, and 1922 to 1924. Between 1954 and 2016, California experienced one FEMA-declared emergency (EM) classified as a drought: FEMA Declaration EM-3023 in 1977, which applied to 58 California counties, including Santa Clara County.148F 149 Santa Clara’s drought history includes
years of drought followed by years with little drought.  1976 to 1977: California had one of its most severe droughts during the winters of 1976 and 1977. 1977 was the driest period on record in California, with the previous winter recorded as the fourth driest in California’s hydrological history. The cumulative impact led to widespread water shortages and severe water conservation measures across the state. Only 37 percent of normal Sacramento Valley runoff was received.
147 Bay Area Water Supply and Conservation Agency. (n.d.). Hetch Hetchy System. https://bawsca.org/water/supply/hetchhetchy
148 California Department of Water Resources. (n.d.). Drought. https://water.ca.gov/drought/ 149 Federal Emergency Management Agency. (n.d.). California Drought EM-3023-CA. https://www.fema.gov/disaster/3023

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 Over $2.6 billion in crop damage was recorded in 31 counties. Santa Clara County was included in FEMA-3023-EM-CA declaration on January 20, 1977.
 1987 to 1992: California’s received precipitation was well below average levels for four consecutive years. While the Central Coast was most affected, the Sierra Nevada mountains in Northern California and the San Joaquin Valley (Central Valley) were also affected. Water suppliers did not experience shortages until the third or fourth year of the drought. Reservoir storage provided a buffer against drought impacts during the initial years of the drought. In 1991, the State Water Project sharply decreased deliveries to water suppliers, including the San Francisco Bay Area. The SCVWD implemented drought contingency measures such as rationing and mandatory conservation to reach its 25 percent reduction goal. By February 1991, all 58 counties in California were suffering under drought conditions that affected urban, rural, and agricultural areas. Some counties had declared a local drought emergency, but Santa Clara County was not included.
 1993 to 2006: Rainfall in this period reached previous highs, but severe drought conditions returned in 2007.
 2007 to 2009: A governor’s executive order proclaimed a statewide drought emergency on June 4, 2008, after spring 2008 was the driest spring on record, with low snowmelt runoff. On February 27, 2009, after the largest court-ordered water restriction in state history up to that time, a state of emergency was proclaimed for the entire state as the severe drought conditions continued. Santa Clara County received about half of its water through the Sacramento-San Joaquin River Delta, which was already significantly limited that year because of pumping restrictions mandated under the Endangered Species Act.149F 150 Water deliveries through the Delta
were cut by about 20 to 30 percent. The SCVWD had mandatory water conservation and rationing measures in effect to reduce usage by 15 percent.
 2012 to 2017: California’s drought has set several records. From 2012 to 2014, it ranked as the driest three consecutive years for statewide precipitation. New climate records were set in 2014 for statewide average temperatures and for record-low water allocations from State Water Project and Central Valley Project contractors. A statewide drought emergency was declared in January 2014. Minimum annual precipitation records were set for many communities in 2013. Executive orders and regulations called for water conservation and management. A new law requires retail urban water suppliers with more than 3,000 customers to establish rules defining “excessive water use” and impose those rules during drought emergencies. On its website, DWR refers to “the five-year drought that ended in 2016.150 F
151 On April 2, 2017, Governor Brown lifted the drought emergency imposed in 2014 but declared that California must continue water conservation efforts USGS).15F
152
 2017 to Present: The National Drought Mitigation Center developed the Drought Impact Reporter152 F
153 as a national drought impact database for the United States. Information comes from a variety of sources: on-line, drought- related news stories and scientific publications, members of the public who visit the website and submit a drought-related impact for their region, members of the media, and members of relevant government agencies. The database is being populated beginning with the most recent impacts and working backward in time. 150 U.S. Fish and Wildlife Service. (n.d.). Endangered Species Act. https://www.fws.gov/media/endangered-speciesact 151 California Department of Water Resources. (n.d.). Countywide Drought and Water Shortage Contingency Plans. https://water.ca.gov/Programs/Water-Use-And-Efficiency/2018-Water-Conservation-Legislation/County-DroughtPlanning 152 USGS. (n.d.). 2012-2016 California Drought: Historical Perspective. (https://ca.water.usgs.gov/californiadrought/california-drought-comparisons.html 153 National Drought Mitigation Center. (n.d.). Drought Impact Reporter. https://www.drought.gov/data-mapstools/drought-impact-reporter-dir

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Between January 2017 and January 2023, the Drought Impact Reporter153F 154 described more than
fifty incidents of drought-related events in the Santa Clara OA. Highlights of that list are presented below.
▪ Feb. 8, 2017: The State Water Resources Control Board opted to keep the water restrictions until spring to see how the rest of winter plays out, in terms of precipitation, before making any changes to the restrictions.
▪ March 22, 2017: Farmers south of the Sacramento-San Joaquin Delta learned that they would receive 65 percent of full allocations from the U.S. Bureau of Reclamation, despite the heavy rainfall the state has received, leading to flooding, full reservoirs, and deep snowpack. ▪ April 11, 2017: The U.S. Bureau of Reclamation announced that South of Delta water contractors would receive a 100 percent allocation from the Central Valley Project. ▪ Jan. 30, 2018: The California Department of Water Resources announced that customers of the State Water Project would receive 20 percent of their requests. ▪ Feb. 22, 2018: Eastside water service contractors will receive 100 percent of their contracts. ▪ 2019: No relevant reports on drought.
▪ Feb. 25, 2020: North-of-Delta agriculture contractors will receive 50 percent of their contracted supply, while South-of-Delta agriculture contractors will receive 15 percent. ▪ Feb. 27, 2020: Northern California ranchers with unirrigated pastures were already giving their cattle supplemental feed as grasses have dried out months earlier than usual. ▪ May 26, 2020: After a dry winter, the State Water Project increased its allocation to 20 percent following above normal precipitation in May.
▪ Feb. 23, 2021: The upcoming March snowpack survey and a planned airborne snow survey will provide more information on the amount of water available for growers. The Tuolumne snowpack measured just 55.6 percent of the historical average for the date. ▪ March 17, 2021: Customers of the Santa Clara Valley Water District were urged to increase their conservation efforts, but no water restrictions were mandated just yet. ▪ March 23, 2021: The California Department of Water Resources updated its initial water allocation for the 2021 water year to 5 percent of requested supplies, down from 10 percent as announced in December 2020.
▪ March 23, 2021: The State Water Board sent notices to California’s 40,000 water users, including small farms and big cities, to alert them to prepare for cuts in water deliveries. ▪ April 28, 2021: The board also voted unanimously to double the price it pays homeowners to use drought-tolerant landscaping from $1 per square foot to $2. The district serves nearly two million people in Santa Clara County.
▪ May 5, 2021: Farmers north of the Sacramento-San Joaquin Delta learned that they will not receive even 5 percent of contracted water from the Central Valley Project. Water deliveries were suspended, due to limited supply, according to the Bureau of Reclamation. ▪ May 26, 2021: The U.S. Bureau of Reclamation announced that municipal water agencies that get water from the Central Valley Project would receive just 25 percent of their allocation. 154 National Integrated Drought Information System. (n.d.). Drought Impact Reporter Dashboard. https://unldroughtcenter.maps.arcgis.com/apps/dashboards/46afe627bb60422f85944d70069c09cf

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▪ May 27, 2021: The federal government announced water cuts to urban areas of more than half, which will lead the Santa Clara Valley Water District. ▪ June 10, 2021: Mandatory water restrictions were issued for Santa Clara County, due to the low water supply.
▪ June 25, 2021: A local emergency was declared in Santa Clara County, due to extreme drought.
▪ July 4, 2021: Farmers were not getting any water from the state or federal projects. ▪ July 8, 2021: California Gov. Gavin Newsom requested that people and businesses curb their water use by 15 percent as intense drought persisted.
▪ Aug 2, 2021: Santa Clara Valley Water District does not have enough water to release to support the fish.
▪ Nov 23, 2021: The San Francisco Public Utilities Commission urged almost 3 million water customers in the Bay Area to curb water use by 10 percent and declared a water shortage emergency.
▪ Dec 2, 2021: The State Water Resources Control Board proposed new emergency drought regulations to discourage water waste as water supplies were low after continued drought. ▪ March 15, 2022: Despite the record dry January and February, Californians are falling short on voluntary water conservation.
▪ May 23, 2022: Urban water use increased 18.9 percent in March. ▪ May 25, 2022: Water users in Santa Clara County could be fined $500, or even up to $10,000, as the Santa Clara Valley Water District enacted new drought rules. ▪ June 7, 2022: Public systems, like the City of San Francisco, will have to have to turn to groundwater or other sources.
▪ Oct 19, 2022: Many trees in California’s forests were turning rust colored as another year of drought and bark beetles or other insects.
▪ Nov 28, 2022: Water storage was near historic lows, with Shasta Reservoir, the largest reservoir in the Central Valley Project, at 31 percent of capacity. ▪ Nov 30, 2022: A survey of California urban water agencies representing about 90 percent of the state’s population showed that about 18 percent, or 73 of the 414 water suppliers, indicated that they will soon face potential shortages. ▪ Dec 1, 2022: The Department of Water Resources announced an initial State Water Project allocation of 5 percent of requested supplies for 2023. ▪ Jan 26, 2023: The series of storms that brought heavy rain and snow to California have partially filled reservoirs, allowing the State Water Project to offer 30 percent of requested water supplies to 29 public water agencies that serve 27 million Californians. The initial allocation in December was just 5 percent.

U.S. Department of Agriculture Disaster Declarations
The U.S. Department of Agriculture (USDA) Farm Service Agency provides assistance for natural disaster losses resulting from drought, flood, fire, freeze, tornadoes, pest infestation, and other natural disasters.

The USDA Secretary of Agriculture is authorized to designate counties as disaster areas to make emergency loans to producers suffering losses in those counties and in contiguous counties.

For drought-related data between 2017 and 2022, the period for which data was available, California has been included in 55 State and County Level Records of Disaster Designation Information made by the US

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Secretary of Agriculture. Santa Clara County was included in seven of these declarations in relation to drought. 154F
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Table 59: U.S. Department of Agriculture Disaster Declarations Including Santa Clara County, 2017–2022
Year Declaration Number(s)
2017 S4144 and S4163
2018 None
2019 None
2020 S4697
2021 S4916, S4969, and S4958
2022 S5146

10.2.2 Location
Drought is a regional phenomenon. A drought that affects the Santa Clara County OA would affect all aspects of the environment and the community simultaneously and has the potential to impact every person directly or indirectly in the county as well as adversely affect the local economy. “The norm for California’s climate is to move back and forth frequently between wet and dry conditions, and water conservation must be a way of life for all who enjoy living in or visiting our state.”
Karla Nemeth, Director of California Department of Water Resources March 12, 2018

10.2.3 Frequency
Historical drought data regarding Santa Clara County indicate four significant droughts over the last 40 years, with drought occurring in 12 of those 40 years.15F 156 Based on risk factors and this history, droughts
likely will continue to occur cyclically in the Santa Clara County OA.

Further information on the impact of climate change on the probability of drought is included in Section

11. Probability in OA: Likely
155 U.S. Department of Agriculture. (n.d.). Disaster Designation Information. https://www.fsa.usda.gov/programs-andservices/disaster-assistance-program/disaster-designation-information/index 156 National Integrated Drought Information System. (n.d.). Drought Conditions for Santa Clara County. https://www.drought.gov/states/california/county/santapercent20clara

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10.2.4 Warning Time
Empirical studies conducted over the past century have shown that meteorological drought is never the result of a single cause. It is the result of many causes, often synergistic in nature; these include global weather patterns that produce persistent, upper-level high-pressure systems along the West Coast with warm, dry air resulting in less precipitation.

Scientists at this time do not know how to predict drought more than a month in advance for most locations. Predicting drought depends on the ability to forecast precipitation and temperature. Anomalies of precipitation and temperature may last from several months to several decades; California is currently finishing a several-year-long drought, while other areas in the United States may undergo droughts as short as 1 or 2 months. How long droughts last depends on interactions between the atmosphere and the oceans, soil moisture and land surface processes, topography, internal dynamics, and the accumulated influence of weather systems on the global scale.

10.2.5 Extent
Figure 48 displays data from the U.S. Drought Monitor for the State of California from 2000 through 2023.

Several periods of moderate to extreme drought have occurred during this time. D0 Abnormally Dry represents the least severe drought conditions and D4 Exceptional Drought represents the most severe.

As noted in 10.2.1 Past Events, significant droughts have occurred from 2007-2009, 2012-2017 and 2000-2023. During these events, significant portions of the entire state were impacted. The OA has experienced conditions from D0 to D4 at different times within this time frame. Figure 49 displays a snapshot of conditions during the most recent drought. During the fall of 2022, the entire OA was experiencing Severe Drought conditions, with the easternmost part of the county experiencing Extreme Drought. As noted in 10.1.4, a significant portion of the OA water supply originates outside of the area which may experience different drought severity.

Figure 49: U.S. Drought Monitor Time Series California 2000-2023

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Figure 50: U.S. Drought Monitory Map of California

10.2.6 Severity and Impacts
The severity of a drought depends on the degree of moisture deficiency, the duration, and the size and location of the affected area. The longer the duration of the drought and the larger the area impacted, the more severe the potential impacts. Drought can have a widespread impact on the environment and the economy, although it typically does not result in loss of life or damage to property, as do other natural disasters. Drought affects agriculture, business and industry, energy, fire, plants, tourism and recreation, and water supply and quality.

The Drought Impact Reporter contains information on 154 impacts from droughts that affected Santa Clara County from January 2017 through January 18, 2023. The following are the categories and reported number of impacts. Note that some impacts have been assigned to more than one category.

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Figure 51: Reported Number of Drought Impacts by Category156F 157
The National Drought Mitigation Center uses three categories to describe drought impacts:
 Economic Impacts: These impacts of drought cost people or businesses money. They include farmers’ loss of crops, costs for irrigation or drilling new wells to address low water supply, lost business for companies that sell boats or fishing equipment, and water companies’ costs for additional water supplies.
 Environmental Impacts: Plants and animals depend on water. When a drought occurs, their food supply can shrink, and their habitat can be damaged.
 Social Impacts: Social impacts include public safety, health, conflicts between people when there is not enough water to go around, and changes in lifestyle.

Drought generally does not affect groundwater sources as quickly as surface water supplies, but groundwater supplies generally take longer to recover. Reduced precipitation during a drought means that groundwater supplies are not replenished at a normal rate. This can lead to a reduction in groundwater levels and problems such as reduced pumping capacity or wells going dry. Shallow wells are more susceptible than deep wells. Reduced replenishment of groundwater affects streams. Much of the flow in streams comes from groundwater, especially during the summer when there is less precipitation and after snowmelt ends. Reduced groundwater levels mean that even less water will enter streams when steam flows are lowest.
157 National Drought Mitigation Center. (n.d.). Drought Impact Reporter. https://www.drought.gov/data-mapstools/drought-impact-reporter-dir

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10.2.7 Responses to Recent Drought
Table 60: Recent Federal and State Drought Responses
Date Federal and State Drought Response
April 2021 Drought emergency proclamation for parts of the state.

May 2021 Drought emergency proclamation issued in April 2021 expanded to include Santa Clara County and $5.1 billion package to:
 Address immediate emergency needs.
 Build regional capacity to endure drought.
 Safeguard water supplies for communities, the economy, and the environment.

July 2021 Voluntary 15 percent water use reduction.

October 2021 State Water Board empowered to prohibit wasteful uses of potable water such as washing sidewalks or driveways.

January 2022 State Water Board prohibited using drinking water for activities such as filling decorative fountains/ponds, washing sidewalks and driveways, watering lawns during and right after rain, and using hoses without automatic shutoff nozzles.

March 2022 Local water suppliers called to move to Level 2 of their Water Shortage Contingency Plans. U.S Department of Agriculture Livestock Forage Disaster Program activated.

August 2022 California’s Water Supply Strategy, which includes creating additional water storage space, recycling and reusing water, increasing efficient water use and conservation, and diversifying water supplies, was released.

September 2022 California Legislature provides additional funds to state residents to replace their lawns with drought-resistant plants and landscaping.

November 2022 The California Department of Water Resources Control Board adopted new performance standards that require urban retail water suppliers to monitor and reduce leakage in their distribution systems. The California Legislature authorized over a billion dollars in funding to the California Department of Water Resources for drought relief in 2021 and 2022.

December 2022 The California Department of Water Resources Control Board extends its emergency regulation to January 2024.

Urban Water Suppliers’ Responses to Defined Drought Stages The California Water Code, Sec. 10632 was amended in 2016 to provide guidance on stages of action to be undertaken by urban water suppliers. It requires them to develop a plan that incorporates an urban water shortage contingency analysis that includes each of the following elements that are within the authority of the urban water supplies. Stages of action to be undertaken by the urban water supplier in response to water supply shortages, including up to a 50 percent reduction in water supply.

The extreme drought and water shortage emergency condition in summer 2022 called for water use restrictions. In responding to the drought condition, the SCVWD declared a water shortage emergency condition in June 2021 that called for 15 percent water use reduction to minimize water shortage risk. The call for water conservation has been instrumental in reducing county-wide water use and helps alleviate the negative consequence of the ongoing drought.

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Since the call, county-wide water use has been reduced by 6 percent cumulatively against a 2019 baseline.157F
158 In winter 2023 when this plan is being written, conditions continue to improve; but the county is still in a “D-1 Moderate Drought”. Participating municipality retail water providers’ drought contingency measures are described in the annexes in Volume 2 of this hazard mitigation plan, as applicable.

10.3 Cascading Hazards
When natural hazard events overlap or occur in quick succession, the events can compound and cause detrimental effects. Drought is particularly likely to be part of a cascading hazard because it can cover a large area and go on for a long time.158F
159

10.3.1 Drought and Wildfire
The hazard most associated with drought is wildfire (see Section 8). A prolonged lack of precipitation dries out vegetation, which becomes increasingly susceptible to ignition as the duration of the drought extends. Reduced ponds, streams, and reservoir levels can also limit withdrawal sources for fighting wildfires. The extreme conditions can also increase the likelihood of shrub and tree mortality by wildfire in previously fire-adapted ecosystems, Millions of board feet of timber have been lost, and in many cases, erosion occurred, which caused considerable damage to aquatic life, irrigation, and power production by heavy silting of streams, reservoirs, and rivers in addition to habitat and infrastructure losses and threats to animal and human life.

10.3.2 Drought and Extreme Heat
Drought is often accompanied by extreme heat, exposing people to the risk of sunstroke, heat cramps and heat exhaustion. Periods of extreme heat increase evaporation, leading to reduced water availability in soils and surface water supplies. Periods of drought can cause extreme heat due to lack of water in the atmosphere, soils, and rivers, where decreased water availability in the system reduces the amount of evaporation happening at the surface, quickly increasing temperatures. Extreme heat can also increase water demands, in which human activities can reduce water supplies, leading to human-caused drought.

These hazards occurring together can compound health impacts, reduce energy production, cause loss of aquatic life due to reduced stream and reservoir levels and increased water temperatures, kill vegetation, and create dangerous air quality issues.

10.3.3 Drought and Flooding
Drought, along with wildfires that can stem from drought, increases flood risk. Extended drought and wildfire can stress and reduce the amount of vegetation. When it does rain, the reduction of vegetation can increase flooding due to faster runoff rates, compared to normal conditions when abundant vegetation slows runoff and increases water absorption into the ground. Drought or wildfire conditions prior to flooding can also cause water quality deterioration from the increased soil and ash particles in the runoff. On farmlands, drought conditions prior to flooding may also cause a surge of farm chemicals applied to crops to enter streams through runoff. These factors can affect the water quality for aquatic life, animals, and humans, who are all dependent on the water source. Increased instances of flash flooding may also occur.
158 Santa Clara Valley Water District. (2022, November 22). Board of Directors Meeting Agenda. https://scvwd.legistar.com/Calendar.aspx
159 American Planning Association. (2019). Falling Dominoes: A Planner’s Guide to Drought and Cascading Impacts. https://abag.ca.gov/sites/default/files/falling-dominoes-planners-guide-to-drought-and-cascading-impacts.pdf

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10.3.4 Drought and Landslides
Droughts can indirectly cause landslides through a cascade of natural hazards. For example, drought can cause dry conditions and increased fuel loads for wildfires that, in turn, can increase the likelihood of flooding. The ash-infused topsoil, which is water repellent, and loss of vegetation can increase runoff and take large amounts of earthen material with them, causing devastating impacts to populations in the path of the landslide event. Such events could cause the loss of infrastructure and life. From an environmental standpoint, they may also affect the water quality of downstream rivers and streams and the habitat for animals, flora, and fauna. Landslides can also alter the topography of the landscape, which can modify surface and groundwater flow patterns.

10.4 Vulnerability
Changes in conditions: increase in vulnerability
 The CMRA tool in Figure 51 shows an increasing number of days without precipitation and an increase in the consecutive number of days without precipitation.  Extended periods of drought have the potential to impact the water supply in the OA.  Drought results in dryer vegetation and increased tree mortality, which compounds conditions that contribute to wildfire risk.
 Loss of vegetation due to drought may increase vulnerability to landslides.  Ongoing drought may contribute to land subsidence if groundwater is not recharged.  SCVWD is implementing recycled and purified water programs to provide access to droughtresistant water supply.  The National Risk Index reports and Expected Annual Loss of $1,771,981 for drought based on crop impacts.
 Santa Clara has adopted the Water Efficient Landscape Ordinance to promote water use efficiency and sustainable landscape design practices.

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Figure 52: CMRA Drought Hazard: Days without Precipitation Indicator for Santa Clara County

10.4.1 Population
The entire population of the Santa Clara County OA is vulnerable to drought events. Drought can affect people’s health and safety, including health problems related to low water flows, insect infestation, poor water quality, or dust. Droughts can also lead to loss of human life.159F 160 The Centers for Disease Control
and Prevention (CDC) has identified the indirect role of drought in people’s deaths through disruptions of agriculture and water systems, poor air quality, and increased heat-related and respiratory illnesses. In a recent study, they have also addressed the increased occupational psychosocial stress among U.S. farmers.160F
161 Other possible impacts include recreational risks; effects on air quality; diminished living conditions related to energy, air quality, and hygiene; compromised food and nutrition.

These negative health effects are more likely to impact populations that already have higher health risks, such as the old or young. Hazus 6.0 demographic data indicates that 260,705 persons or 13.5 percent of the population in the OA are over 64 years old and 422,719 persons or 21.8 percent of the population within the OA under 18 years of age. These people may experience worse effects from poor air quality or reduced nutrition resulting from agricultural production loss. It is also estimated that 2.45 percent of the people within the OA are economically disadvantaged, defined as having household incomes of $20,000 or less. Those with fewer financial resources are often less resilient to hazard impacts.

The SCVWD, BAWSCA, regional water purveyors, and other regional stakeholders have devoted considerable time and effort to protect life, safety, and health during times of consecutive dry years, such as the current drought. Provisions and measures have been taken to analyze and account for anticipated 160 National Oceanic and Atmospheric Administration. (2016, June 15). Drought in America: Slow Moving, Far Reaching. https://www.noaa.gov/explainers/drought-in-america-slow-moving-far-reaching 161 National Integrated Drought Information Systems. (2021, July 24). The Association Between Drought Conditions and Increased Occupational Psychosocial Stress Among U.S. Farmers. https://www.drought.gov/documents/association-between-drought-conditions-and-increased-occupationalpsychosocial-stress

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water shortages. With coordination from its cities, the SCVWD has the ability to minimize and reduce impacts on residents and water consumers in the Santa Clara County OA.

10.4.2 Property
Significant depletion of groundwater supplies—from drought, excessive groundwater pumping or both— can lead to subsidence, which is the downward collapse of the land surface when groundwater aquifers lack the water to support the weight of the ground. Compaction of aquifer systems is the greatest cause of subsidence in California. Although this is typically due to groundwater pumping rather than drought, drought creates a need for greater groundwater pumping as freshwater sources disappear. Droughtinduced subsidence is not as common as wildfire or extreme heat, but it can significantly impact the local environment, floodplain/wetlands, and water supply, and it typically is irreversible. It may cause wetlands to change size and shape, migrate to lower elevations, or disappear entirely. Rivers may change course, and patterns of erosion and deposition may change.16F
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No structures will be directly affected by drought conditions, though droughts often lead to reduced local fire suppression capabilities which could threaten structures. Some structures may become vulnerable to wildfires, which are more likely following years of drought.

Drought conditions may also be the cause of serious foundation problems and have significant impacts on landscapes, which could cause a financial burden to property owners. However, these impacts are not considered critical in planning for impacts from the drought hazard.

Drought is detrimental to agricultural assets and other natural resources. Although the agricultural sector is relatively small in the OA, a significant area in the southeast area of the county near Gilroy is involved in agricultural production. Extended drought may diminish the productivity of agricultural lands and impact their value. The National Risk Index reports and Expected Annual Loss of $1,771,981 to crops due to drought in Santa Clara County. This area would likely feel more significant impact of drought due to crop losses caused by drought or impacts to water supplies.