Agenda packet — Oakdale City Council, June 15, 2026 (part 4 of 6)

Certain shortage response actions are expected to result in measurable reductions in water demand.

Other actions, including public outreach, education, and communication efforts, support the overall effectiveness of the City’s water shortage response but may not be independently quantifiable. These supporting actions are nonetheless essential to promoting public awareness, encouraging voluntary conservation, and reinforcing mandatory requirements.

The City will evaluate the effectiveness of shortage response actions using multiple indicators, including, but not limited to:
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20 • Progress toward achieving the demand reduction targets associated with the declared water shortage level;
• Trends in total system water use and water use by customer sector; • The number and nature of reported or observed water waste violations; • Customer compliance rates and enforcement outcomes; and • Input and feedback from City staff and the public.

If monitoring indicates that implemented shortage response actions are not sufficient to address the identified supply shortfall, the City may intensify existing actions, implement additional measures identified in this WSCP, or advance to a higher water shortage level, as appropriate. Conversely, if water supply conditions improve or demand reductions exceed targets, the City may modify or relax response actions while continuing to ensure water supply reliability.

The results of this evaluation will inform the City’s Annual Assessment, ongoing operational decisionmaking, and future refinements to the WSCP, consistent with the adaptive management approach described in Section 11, WSCP Refinement Procedures.
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21 6 Communication Protocols
Legal Requirements:

Water Code Section 10632 (a)(5)
Communication protocols and procedures to inform customers, the public, interested parties, and local, regional, and state governments, regarding, at a minimum, all of the following:
(A) Any current or predicted shortages as determined by the annual water supply and demand assessment described pursuant to Section 10632.1.
(B) Any shortage response actions triggered or anticipated to be triggered by the annual water supply and demand assessment described pursuant to Section 10632.1. (C) Any other relevant communications
In the event of a water shortage, the City will provide timely and effective communication to customers, the general public, interested parties, and relevant local, regional, and state agencies. Clear and consistent communication is essential to ensure appropriate response actions, public awareness, and regulatory coordination during both foreseeable and unforeseeable water shortage conditions.

This section describes City’s communication protocols for anticipated water shortages identified through planning and assessment activities, as well as for unanticipated emergency events.

6.1 Communication for Foreseeable Events
Water shortage conditions may be foreseeable when identified through the Annual Assessment, as described in Section 3. When the potential for a water shortage is identified, the City’s Council may determine and declare a water shortage emergency in accordance with the OMC.

The City will hold a duly noticed public meeting to present the current or projected water shortage conditions identified through the Annual Assessment. At the public meeting, the City Council will determine whether a water shortage emergency exists, the severity of the shortage, and the applicable water shortage level. The City Council will also consider the shortage response actions triggered or anticipated to be triggered by the declared shortage level, and may adopt a resolution declaring a water shortage emergency, establishing the applicable shortage level, and authorizing the implementation of response actions.

For foreseeable water shortage events, the City may implement one or more of the following communication actions at any water shortage level, as appropriate:

1. Coordinate internally and with regional water service providers and Stanislaus County regarding the potential proclamation of a local emergency.

2. Issue public notice of City Council meetings at which Annual Assessment findings and recommendations related to water shortage conditions and response actions will be presented.

3. Communicate water shortage conditions, response actions, and customer responsibilities through a combination of bill inserts, newsletters, the City website, social media, press releases, and blog posts.
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22 4. Communicate with relevant local, regional, and state agencies and officials, primarily through email correspondence.

6.2 Communication for Unforeseeable Events
Water shortages may also result from unforeseeable events such as earthquakes, fires, infrastructure failures, civil unrest, or other catastrophic incidents. In these circumstances, communication protocols and procedures outlined in City’s ERP will guide notification and public information activities. Depending on the nature and severity of the event, the City may implement communication actions at any water shortage level.
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23 7 Compliance and Enforcement
Legal Requirements:

Water Code Section 10632 (a)(6)
For an urban retail water supplier, customer compliance, enforcement, appeal, and exemption procedures for triggered shortage response actions as determined pursuant to Section 10632.2.

Customer compliance with the triggered shortage response actions will be enforced through cease-anddesist orders and penalties, as described in Article VI, Water Conservation Program, Chapter 35 Section 49 of the OMC. This section of the OMC also includes details for an appeal process. 775
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24 8 Legal Authorities
Legal Requirements:

Water Code Section 10632 (a)(7)
(A) A description of the legal authorities that empower the urban water supplier to implement and enforce its shortage response actions specified in paragraph (4) that may include, but are not limited to, statutory authorities, ordinances, resolutions, and contract provisions. (B) A statement that an urban water supplier shall declare a water shortage emergency in accordance with Chapter 3 (commencing with Section 350) of Division 1. [see below] (C) A statement that an urban water supplier shall coordinate with any city or county within which it provides water supply services for the possible proclamation of a local emergency, as defined in Section 8558 of the Government Code.

Water Code Section Division 1, Section 350
Declaration of water shortage emergency condition. The governing body of a distributor of a public water supply, whether publicly or privately owned and including a mutual water company, shall declare a water shortage emergency condition to prevail within the area served by such distributor whenever it finds and determines that the ordinary demands and requirements of water consumers cannot be satisfied without depleting the water supply of the distributor to the extent that there would be insufficient water for human consumption, sanitation, and fire protection.

Article VI, Water Conservation Program, Chapter 35 Section 49 of the OMC provides the City the authority to implement and enforce its shortage response actions. When the conditions deem it necessary, the City shall declare a water shortage emergency in accordance with CWC Chapter 3 (commencing with Section 350) of Division 1 general provision regarding water shortage emergencies. Because the City is also the water supplier, City staff can coordinate the possible proclamation of a local emergency under California Government Code, California Emergency Services Act (Article 2, Section 8558).

CWC Division 1, Section 350 provides that:
“…The governing body of a distributor of a public water supply…shall declare a water shortage emergency condition to prevail within the area served by such distributor whenever it finds and determines that the ordinary demands and requirements of water consumers cannot be satisfied without depleting the water supply of the distributor to the extent that there would be insufficient water for human consumption, sanitation, and fire protection.”
Declaration of a water shortage emergency under this authority triggers implementation of the communication protocols described in Section 6 and the compliance and enforcement procedures described in Section 7 of this WSCP.
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25 9 Financial Consequences of WSCP
Legal Requirements:

Water Code Section 10632(a)(8)
A description of the financial consequences of, and responses for, drought conditions, including, but not limited to, all of the following:
(A) A description of potential revenue reductions and expense increases associated with activated shortage response actions described in paragraph (4).
(B) A description of mitigation actions needed to address revenue reductions and expense increases associated with activated shortage response actions described in paragraph (4). (C) A description of the cost of compliance with Chapter 3.3 (commencing with Section 365) of Division

1. Revenues required to operate and maintain the City’s water system are generated through customer water rates. A Water and Wastewater Rate Study (Rate Study) was prepared for the City in January 2017 and the City is in the process of updating the water rates. The adopted water rate consists of fixed and variable charges to residential and non-residential customers and is intended to generate sufficient revenue to properly operate and maintain the water system. The City also conducted a public hearing on June 1, 2026, to consider proposed revisions to the current water rates.

During periods when water shortage response actions are implemented, overall water sales revenues are expected to decline as a result of reduced water consumption. However, the costs for operating the water system will not correspondingly decrease. There may also be additional costs associated with implementing the shortage response actions and enforcing compliance.

The City annually adopts a budget and mid-year budget for each fiscal year for the water fund. The budgets summarize the projected revenues and expenses for the City’s water production and distribution system for the upcoming fiscal year. The projections are updated in the mid-year budget. To mitigate reductions in revenue and increases in expenses associated with reduced consumption, the City may decide to use financial reserves, defer capital replacement projects or operations and maintenance activities, and/or reevaluate the water rates to implement a drought rate structure or surcharge. 777
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26 10 Monitoring and Reporting
Legal Requirements:

Water Code Section 10632(a)(9)
For an urban retail water supplier, monitoring and reporting requirements and procedures that ensure appropriate data is collected, tracked, and analyzed for purposes of monitoring customer compliance and to meet state reporting requirements.

The City’s water system is fully metered, from water supply sources through individual customer connections. Metering data are used as primary tools for monitoring water use, assessing compliance with water shortage response actions, and supporting reporting requirements associated with this WSCP. Most of the City’s current water treatment and distribution systems are equipped with a Supervisory Control and Data Acquisition (SCADA) system, which allows for monitoring and management of the water system.

Using several monitoring techniques, including pressure, tank level, equipment status, etc., the SCADA system continuously analyzes the system, reports data to a centralized location, and adjusts the operation of water system equipment according to logic-based protocols.

Water use data will be evaluated regularly to determine whether demand-reduction goals associated with declared water-shortage levels are being achieved. If reduction targets are not met during implementation of the WSCP at any water shortage stage, the City Council will be notified and recommended additional or more aggressive response actions, as appropriate.

Monitoring results may also be used to evaluate the effectiveness of WSCP measures and to identify opportunities for improvement. If revisions to the WSCP are determined to be necessary to achieve demand reduction objectives or address changing conditions, the City will update the WSCP in accordance with the procedures described in Section 11 and make the revised plan available as described in Section

13. 778
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27 11 WSCP Refinement Procedures
Legal Requirements:

Water Code Section 10632(a)(10)
Reevaluation and improvement procedures for systematically monitoring and evaluating the functionality of the water shortage contingency plan in order to ensure shortage risk tolerance is adequate and appropriate water shortage mitigation strategies are implemented as needed.

This WSCP is intended to function as an adaptive management document and may be refined as necessary to ensure that City’s shortage response actions and mitigation strategies remain effective and achieve the intended outcomes. Based on monitoring activities described in Section 10, and the compliance and enforcement results described in Section 7, the City may adjust response actions and revise this WSCP to address changing conditions, implementation challenges, or observed performance.

When revisions to the WSCP are proposed, the updated plan will undergo the adoption process described in Section 13, including consideration by the City Council and distribution to Stanislaus County, OID, City customers, and the general public, as applicable.

Feedback from the City staff and the public is an important component of the WSCP refinement process.

The City will seek input from staff who regularly interact with customers and implement water shortage response actions to assess the practicality and effectiveness of existing measures and to identify potential improvements or new actions.

Customer water use data may be evaluated by customer sector or by individual account to assess the effectiveness of demand reduction measures and compliance trends. The City will track water use violations and may evaluate their frequency and characteristics to identify restrictions that may be difficult for customers to comply with, as well as demand reduction actions that are particularly effective.

The City will also seek input from customers and the general public through its website and during regularly scheduled City Council meetings to inform future refinements to the WSCP. 779
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28 12 Special Water Feature Distinction
Legal Requirements:

Water Code Section 10632 (b)
For purposes of developing the water shortage contingency plan pursuant to subdivision (a), an urban water supplier shall analyze and define water features that are artificially supplied with water, including ponds, lakes, waterfalls, and fountains, separately from swimming pools and spas, as defined in subdivision (a) of Section 115921 of the Health and Safety Code.

In accordance with Water Code Section 10632 (b), swimming pools and spas are considered different from other water features that are artificially supplied with water, including ponds, lakes, waterfalls, and fountains. The City follows the definition of a swimming pool found in the Swimming Pool Safety Act. As such, non-pool or non-spa water features, also referred to as “decorative water features” may use or be able to use recycled water, whereas pools and spas must use potable water for health and safety considerations.
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29 13 Plan Adoption, Submittal and Availability
Legal Requirements:

Water Code Section 10632(c)
The urban water supplier shall make available the water shortage contingency plan prepared pursuant to this article to its customers and any city or county within which it provides water supplies no later than 30 days after adoption of the water shortage contingency plan.

Water Code Section 10642
…Prior to adopting either [UWMP and WSCP], the urban water supplier shall make both the plan [UWMP] and water shortage contingency plan available for public inspection and shall hold a public hearing or hearings thereon…After the hearing or hearings, the plan [UWMP] or water shortage contingency plan shall be adopted as prepared or as modified after the hearing or hearings.

Water Code Section 10640
(b) …The supplier shall likewise periodically review the water shortage contingency plan as required by paragraph (10) of subdivision (a) of Section 10632 and any amendments or changes required as a result of that review shall be adopted pursuant to this article [Article 3 Sections 10640 -10645] Water Code Section 10644(a)(2)(b)
If an urban water supplier revises its water shortage contingency plan the supplier shall submit to the department a copy of it water shortage contingency plan prepared pursuant to subdivision (a) of Section 10632 [required elements of a WSCP] no later than 30 days after adoption, in accordance with protocols for submission and using electronic reporting tools developed by the department.

This WSCP is adopted concurrently with the City’s 2025 UWMP, by separate resolution. Prior to adoption, two notices of public hearing were placed in the local newspaper. A hard copy and electronic copy of this WSCP will be submitted to DWR within 30 days of adoption. Refer to Appendix B for public notices and outreach efforts.

No later than 30 days after submittal to DWR, copies of this WSCP will be available at the City’s offices. A copy will also be provided to Stanislaus County and OID. An electronic copy of this WSCP will also be available for public review and download on the City’s website. A copy of the City resolution is included in Appendix C.
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A
Appendix A
Stanislaus County Multi-Jurisdictional Hazard Mitigation Plan 782
Stanislaus County
2022 Multi-Jurisdictional Hazard Mitigation Plan
Prepared for:

Stanislaus County
3705 Oakdale Road
Modesto, CA 95357
Prepared by:

Wood Environment & Infrastructure Solutions, Inc.
10940 White Rock Road, Suite 190
2022-2027 Rancho Cordova, CA 95670
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Stanislaus County Multi-Jurisdictional Hazard Mitigation Plan Executive Summary
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EXECUTIVE SUMMARY
The purpose of hazard mitigation is to reduce or eliminate long-term risk to people and property from hazards. The County of Stanislaus (County) developed this Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) update to make the County, its 10 participating jurisdictions, and its residents less vulnerable and more resilient to future hazard events. This plan was prepared pursuant to the requirements of the Disaster Mitigation Act of 2000 so that Stanislaus County would be eligible for the Federal Emergency Management Agency’s (FEMA) Pre-Disaster Mitigation and Hazard Mitigation Grant programs.

The County followed a planning process prescribed by FEMA, which began with the formation of a hazard mitigation planning committee (HMPC) comprised of key County representatives, 10 participating jurisdictions from the cities of Hughson, Modesto, Newman, Oakdale, Riverbank, Waterford, Patterson, Turlock, and Ceres, the Stanislaus County Office of Education (SCOE), and other regional stakeholders.

The HMPC conducted a risk assessment that identified and profiled hazards that pose a risk to the County of Stanislaus, assessed the County’s vulnerability to these hazards, and examined the capabilities in place to mitigate them. The County is vulnerable to several hazards that are identified, profiled, and analyzed in this plan. Earthquakes, dam incidents, drought, floods, severe weather (dense fog; heavy rain, thunderstorm, hail, and lightning; and high wind and tornado), and wildfires are among the hazards that can have a significant impact on the County.

Based on the risk assessment review and goal setting process, the HMPC identified and modified the following five goals from their previous HMP, which provide the direction for reducing future hazard-related losses within the County’s Planning Area:
• Goal 1: Minimize the loss of life and reduce property damage as a result of natural, human-health, and human-caused hazards to support the health and safety of the whole community. • Goal 2: Reduce economic impacts and promote a sustainable economy. • Goal 3: Improve community resilience to disasters through increased outreach and awareness and better resources.
• Goal 4: Protect climate and socially vulnerable communities in the County, including individuals with access and functional needs and those that may suffer from economic, health, and environmental burdens.
• Goal 5: Build resilient infrastructure and communities that withstand climate-related impacts.

The HMPC also developed and updated 71 objectives. To meet identified goals and objectives, the plan recommends 125 mitigation actions, which are summarized in the table that follows. Once formally approved by the California Office of Emergency Services (Cal OES) and FEMA Region IX and adopted by the County and their participating jurisdictions, this plan will be updated every five years. 784
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Table ES-1 Mitigation Actions Summarized by Jurisdictions and Hazards Mitigated Hazard
Jurisdiction
Stanislaus
County Ceres Hughson Modesto Newman Oakdale Patterson Riverbank Turlock Waterford Office of Education Multi-Hazard 5 - - 1 3 - - 3 - 1 8
Agriculture Pest and
Disease - - - - - - - - - - -
Aquatic Invasive
Species - - - - - - - - - - -
Cyber Attack 1 - - - - - - - - - -
Dam Incidents 5 2 3 - - 1 1 1 1 1 1
Drought 1 2 1 - 1 1 2 - 7 - -
Earthquake 6 - - - 2 - 2 - - - 3
Extreme
Temperature 1 - 1 - 1 - 1 - 1 - -
Flood 12 - 1 2 2 1 3 1 - - -
Landslide 6 - - - - - - 1 - - -
Public Health
Hazards:

Pandemic/Epidemic
1 - 1 - - - -
1 - - 4
Severe Weather 3 - - - - - - - - - 2
Wildfire 9 - - - - 1 3 - - - -
Total 50 4 7 3 9 4 12 7 9 2 18
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Stanislaus County Multi-Jurisdictional Hazard Mitigation Plan Table of Contents
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TABLE OF CONTENTS
Executive Summary ....................................................................................................................................... i Annexes ........................................................................................................................................................ v 1 Introduction ................................................................................................................................... 1-1

1.1 Purpose of Plan................................................................................................................ 1-1

1.2 Hazard Mitigation Planning .............................................................................................. 1-1

1.3 Federal Regulatory Framework ....................................................................................... 1-2

1.4 State and Local Regulatory Framework........................................................................... 1-2

1.5 Emergency Management Accreditation Process (EMAP) Standards.............................. 1-2

1.6 Background and Scope.................................................................................................... 1-3

1.7 Plan Update ..................................................................................................................... 1-3

1.8 Multi-Jurisdictional Planning ............................................................................................ 1-4

1.9 Plan Organization............................................................................................................. 1-5

1.10 Appendices ...................................................................................................................... 1-6

1.11 Annexes ........................................................................................................................... 1-6 2 Community Profile and Capability Assessment ............................................................................ 2-1

2.1 History .............................................................................................................................. 2-1

2.2 Geography and Climate ................................................................................................... 2-2

2.3 Rivers ............................................................................................................................... 2-2

2.4 Population ........................................................................................................................ 2-2

2.5 Economy .......................................................................................................................... 2-5

2.6 Unemployment Rate Comparison.................................................................................... 2-6

2.7 Commuters....................................................................................................................... 2-7

2.8 Housing ............................................................................................................................ 2-8

2.9 Housing and Development Trends .................................................................................. 2-9

2.10 Transportation ................................................................................................................ 2-10

2.11 Highways/Roads/Bridges............................................................................................... 2-10

2.12 Airports........................................................................................................................... 2-10

2.13 Railroads ........................................................................................................................ 2-11

2.14 Medical Facilities............................................................................................................ 2-11

2.15 Arts, Entertainment and Recreation............................................................................... 2-11

2.16 County’s Mitigation Capabilities ..................................................................................... 2-11

2.16.1 Regulatory Mitigation Capabilities..................................................................... 2-12

2.16.2 Related Plans and Regulations......................................................................... 2-14

2.16.3 Administrative and Technical Mitigation Capabilities........................................ 2-17

2.16.4 Fiscal Mitigation Capabilities............................................................................. 2-20

2.16.5 Other Mitigation Programs and Partnerships.................................................... 2-21

2.16.6 Opportunities for Enhancement ........................................................................ 2-22 3 Planning Process .......................................................................................................................... 3-1

3.1 Background on Mitigation Planning in Stanislaus County ............................................... 3-1

3.2 What’s New in the Plan Update ....................................................................................... 3-1

3.2.1 Plan Section Review and Analysis – 2021 Update............................................. 3-2

3.3 Multi-Jurisdictional Participation....................................................................................... 3-4

3.4 Planning Process ............................................................................................................. 3-5

3.4.1 Phase 1: Organize Resources ............................................................................ 3-6

3.4.2 Planning Step 3: Coordinate with Other Departments and Agencies............... 3-16

3.4.3 Phase 2: Assess Risks ..................................................................................... 3-21

3.4.4 Phase 3: Develop the Mitigation Plan............................................................... 3-22

3.4.5 Phase 4: Implement the Plan and Monitor Progress ........................................ 3-23

3.4.6 EMAP Standards Crosswalk............................................................................. 3-24 4 Hazard Identification and Risk Assessment.................................................................................. 4-1

4.1 Hazard Identification ........................................................................................................ 4-2

4.1.1 Overall Hazard Significance Summary ............................................................... 4-3

4.1.2 Non-Profiled Hazards.......................................................................................... 4-4 786
Stanislaus County Multi-Jurisdictional Hazard Mitigation Plan Table of Contents
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4.1.3 Disaster Declaration History ............................................................................... 4-4

4.1.4 Climate Change Considerations Summary......................................................... 4-6

4.1.5 Overview of Hazard Identification, Risk Assessment, and Consequence Analysis............................................................................................................... 4-7

4.2 Asset Summary................................................................................................................ 4-8

4.2.1 Assets Exposure ................................................................................................. 4-8

4.3 Hazard Analysis and Risk Summary.............................................................................. 4-21

4.3.1 Agricultural Pests and Disease......................................................................... 4-21

4.3.2 Aquatic Invasive Species (AIS)......................................................................... 4-26

4.3.3 Cyber Attack...................................................................................................... 4-33

4.3.4 Dam Incidents ................................................................................................... 4-37

4.3.5 Drought ............................................................................................................. 4-46

4.3.6 Earthquake........................................................................................................ 4-56

4.3.7 Extreme Temperatures: Freeze and Extreme Heat.......................................... 4-84

4.3.8 Flood ................................................................................................................. 4-93

4.3.9 Landslide......................................................................................................... 4-119

4.3.10 Public Health Hazards: Pandemics/Epidemics............................................... 4-128

4.3.11 Severe Weather: General ............................................................................... 4-137

4.3.12 Severe Weather: Dense Fog .......................................................................... 4-138

4.3.13 Severe Weather: Heavy Rain, Thunderstorms, Hail, and Lightning ............... 4-143

4.3.14 Severe Weather: High Wind/Tornado............................................................. 4-156

4.3.15 Wildfire ............................................................................................................ 4-167 5 Mitigation Strategy ........................................................................................................................ 5-1

5.1 Mitigation Goals and Objectives ...................................................................................... 5-1

5.1.1 Mitigation Goals: ................................................................................................. 5-2

5.1.2 Mitigation Objectives by Hazard ......................................................................... 5-2

5.2 Identification and Analysis of Mitigation Actions .............................................................. 5-5

5.2.1 Prioritization Process .......................................................................................... 5-7

5.2.2 Continued Compliance with the National Flood Insurance Program (NFIP) ...... 5-8

5.3 Mitigation Strategy Action Plan ........................................................................................ 5-9

5.3.1 Progress on Previous Mitigation Actions .......................................................... 5-10

5.3.2 Updated Action Plan ......................................................................................... 5-12 6 Plan Adoption, Implementation, and Maintenance ....................................................................... 6-1

6.1 Adoption ........................................................................................................................... 6-1

6.2 Implementation................................................................................................................. 6-1

6.2.1 Role of the Hazard Mitigation Planning Committee (HMPC) in Implementation and Maintenance..................................................................................................................... 6-2

6.3 Maintenance and Monitoring............................................................................................ 6-2

6.3.1 Maintenance Schedule ....................................................................................... 6-2

6.3.2 Maintenance and Evaluation Process ................................................................ 6-3

6.3.3 Incorporation into Existing Planning Mechanisms .............................................. 6-4

6.3.4 Continued Public Involvement ............................................................................ 6-5 7 Plan Adoption................................................................................................................................ 7-1

7.1 Element E.1 Formal Plan Adoption Documentation ........................................................ 7-1

7.2 General Plan Safety Element Integration......................................................................... 7-1 8 References.................................................................................................................................... 8-1

LIST OF APPENDICES
Appendix A: Hazard Mitigation Planning Committee
Appendix B: Planning Process Documentation
Appendix C: Approval and Adoption Documentation
Appendix D: Mitigation Categories and Alternatives
Appendix E: Annual Progress Meeting Agenda and Report Template Appendix F: Outreach Strategy
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ANNEXES
Annex A: City of Ceres
Annex B: City of Hughson
Annex C: City of Modesto
Annex D: City of Newman
Annex E: City of Oakdale
Annex F: City of Patterson
Annex G: City of Riverbank
Annex H: City of Turlock
Annex I: City of Waterford
Annex J: County Office of Education
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1 INTRODUCTION

1.1 Purpose of Plan
Stanislaus County including the participating jurisdictions have prepared this multi-jurisdictional hazard mitigation plan (MJHMP) to guide hazard mitigation planning to better protect the people and property of the County from the effects of hazard events. The purpose of this MJHMP is to identify policies, actions, and strategies that will help to reduce risk and prevent future losses. Hazard mitigation is best realized when community leaders, businesses, citizens, and other stakeholders join together to undertake a process of learning about hazards that can affect their area and use this knowledge to prioritize needs and develop a strategy for reducing damage. Hazard mitigation is most effective when it is based on a comprehensive long-term plan that is developed prior to a disaster occurring.

This plan demonstrates the community’s commitment to reducing risks from hazards and serves as a tool to help decision makers direct mitigation activities and resources. This plan was also developed to make Stanislaus County and the participating jurisdictions eligible for certain federal disaster assistance, specifically, the Federal Emergency Management Agency’s (FEMA) Hazard Mitigation Assistance (HMA) grants including the Hazard Mitigation Grant Program (HMGP), Flood Mitigation Assistance (FMA) and Building Resilient Infrastructure and Communities (BRIC) program, as well as to make the County and jurisdictions more disaster resistant. This plan demonstrates the County’s commitment to reducing risks from hazards and serves as a tool to help decision makers direct mitigation activities and resources.

1.2 Hazard Mitigation Planning
FEMA has determined that there is a critical link between hazard mitigation planning and sustainability.

This means if Stanislaus County has the foresight to plan ahead to reduce the impacts of hazards, the County will be better able to prevent injury, loss of life and damage to our homes, businesses, and neighborhoods. The County can use the threat of disaster as a catalyst to act and develop a plan so we can recover more quickly following a disaster.

Stanislaus County and their 10 participating jurisdictions have committed to reducing long-term risk to our citizens and damage to property from the effects of natural hazards. By planning, preparing, and adopting a MJHMP, the County and each jurisdiction is taking a proactive approach to reduce or eliminate the impacts of hazards before they occur.

FEMA defines “hazard mitigation” as any sustained action taken to reduce or eliminate the long-term risk to human life and property from hazards. The County's plan will serve as a tool for learning from disasters that have already occurred, so we can deal with them more effectively and efficiently with less expenditure than in the past.

Direct benefits include:
• Reduced loss of life;
• Reduced loss of property and essential services;
• Reduced economic hardship;
• Reduced reconstruction costs;
• Increased cooperation and communication within the community through the planning process; and • Expedited post-disaster funding.

Indirect benefits include:
• Disaster resilience;
• Environmental quality;
• Economic vitality; and
• Improved quality of life.
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1.3 Federal Regulatory Framework
Section 322, Mitigation Planning, of the Robert T. Stafford Disaster Relief and Emergency Assistance Act (“the Stafford Act”), enacted by Section 104 of the Disaster Mitigation Act of 2000 (“DMA 2000”), provides revitalized approaches to mitigation planning. Section 322 continues the requirement for a State mitigation plan as a condition of disaster assistance and establishes a new requirement for LHMPs. In order to apply for federal aid for technical assistance and post-disaster funding, local jurisdictions must comply with DMA 2000 and its implementing regulations (44 Code of Federal Regulations (CFR) Part 201.6).

Under the 2008 44 CFR update, requirements have changed governing mitigation planning provisions for LHMPs published under 44 CFR §201.6. LHMPs qualify communities for the federal mitigation grant programs including:
• HMA Grants
• HMGP
• BRIC
• FMA
• Severe Repetitive Loss (SRL)
• Repetitive Flood Claim (RFC)

1.4 State and Local Regulatory Framework
The MJHMP was prepared consistent with the Safety Element of the Stanislaus County General Plan, as the planning effort covers common overlapping natural hazard issues and mutually-reinforcing policies and implementation programs. The MJHMP and Safety Element are considered complimentary documents that address natural hazards, and both planning documents contain goals, policies, and project actions or implementation programs to enhance the County’s mitigation efforts related to public safety.

California Government Code Section 65302.10, also referred to as Assembly Bill (AB) 2140 encourages California counties and cities to adopt their current, FEMA-approved Local Hazard Mitigation Plans (LHMPs) into the Safety Element of their General Plan. This adoption by reference or incorporation of the MJHMP into the Safety Element of the General Plan follows plan approval and makes Stanislaus County and each participating jurisdiction eligible to be considered for part or all of its local-share costs on eligible public assistance funding to be provided by the State through the California Disaster Assistance Act (CDAA). The CDAA allows the State to pay up to 18.75 percent (%) of the non-federal share that would otherwise fall upon a county or city to pay for public assistance projects. The legislature passed AB 2140 to provide additional funding after a disaster occurs. The local share is 25% of the total project cost; therefore, the legislation allows city and counties that comply to be eligible for only the remaining local share (6.25%).

AB 2140 is an optional state incentive to help counties and cities become more resilient to natural hazards.

Compliance with AB 2140 also expires when the MJHMP expires, and the County must re-adopt the plan into the Safety Element during update cycles to ensure continued compliance and funding eligibility.

Additionally, each participating jurisdiction in Stanislaus County must adopt their annex into their own General Plan Safety Element, as the annex jurisdictions are not covered under the County’s General Plan Safety Element adoption.

1.5 Emergency Management Accreditation Process (EMAP) Standards The Emergency Management Accreditation Program (EMAP) is a voluntary standards, assessment, and accreditation process for disaster preparedness programs throughout the country. It provides emergency management programs the opportunity to be recognized for compliance with industry standards, to demonstrate accountability, and to focus attention on areas and issues where resources are needed. The EMAP program consists of 66 standards, last updated in 2019 that evaluate all aspects of a jurisdiction’s comprehensive emergency management program. The standards cover program management, hazard identification: risk assessment and consequence analysis, hazard mitigation, prevention, operation planning and procedures, incident management, resource management, communications, training and exercises, and emergency public education. Two of the EMAP Standards specifically address hazard 790
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assessment and mitigation planning: Standard: 4.1 Hazard Identification, Risk Assessment and Consequence Analysis and Standard: 4.2 Hazard Mitigation. The Stanislaus County MJHMP update was prepared pursuant to the EMAP standards and included an updated risk assessment and consequence analysis in Subsection 4.1 of this plan. The Emergency Management Program consequence analysis considered the impact on the public; responders; continuity of operations; property, facilities, and infrastructure; environment; economic conditions; and public confidence in the jurisdiction’s governance.

Additional information on the EMAP standards and how the MJHMP update complies with the program is provided in Section 3.4.6.

1.6 Background and Scope
In the State of California and around the world, natural disasters occur frequently. Each year in the United States, disasters take the lives of hundreds of people and injure thousands more. Nationwide, taxpayers pay billions of dollars annually to help communities, organizations, businesses, and individuals recover from disasters. The time and money needed to recover from these events can strain or deplete local resources.

These monies only partially reflect the true cost of disasters because additional expenses to insurance companies and non-governmental organizations are not reimbursed by tax dollars. Many disasters are predictable, and much of the damage caused by these events can be alleviated or even eliminated.

Hazard mitigation is defined by FEMA as “any sustained action taken to reduce or eliminate long-term risk to human life and property from a hazard event.” The results of a three-year, congressionally mandated independent study to assess future savings from mitigation activities provides evidence that mitigation activities are highly cost-effective. On average, each dollar spent on mitigation saves society an average of $6 in avoided future losses in addition to saving lives and preventing injuries (Natural Hazard Mitigation Saves: 2017 Interim Report).

Hazard mitigation planning is the process through which hazards that threaten communities are identified; likely impacts are determined, prioritized, and implemented. This MJHMP update continues the hazard mitigation planning process for Stanislaus County, the unincorporated county; the participating cities of Modesto, Turlock, Oakdale, Ceres, Patterson, Riverbank, Newman, Hughson, and Waterford; and the County Office of Education. The plan identifies natural and human-caused hazards and risks within Stanislaus County and identifies the hazard mitigation strategy to reduce vulnerability and make the communities of Stanislaus County more disaster resistant and sustainable. Information in this plan can be used to help guide and coordinate mitigation activities and local land use decisions. Proactive mitigation planning will help reduce the cost of disaster response and recovery to the community and its property owners by protecting critical community facilities, reducing liability exposure, and minimizing overall community impacts and disruption. The Stanislaus County planning area has been affected by hazards in the past and is thus committed to reducing future disaster impacts and maintaining eligibility for federal funding.

1.7 Plan Update
This plan underwent a comprehensive update in 2021-2022 in fulfillment of the five-year update requirement. Several factors underscore the need for this planning effort:
• Stanislaus County is exposed to hazards that have caused past damage. • Limited local resources make it difficult to be pre-emptive in reducing risk. Eligibility for federal financial assistance is paramount to promote successful hazard mitigation in the area. • Stanislaus County and its partners participating in this plan want to be proactive in preparing for the probable impacts of natural hazards.

This MJHMP was originally prepared in 2006, pursuant to the requirements of the Disaster Mitigation Act of 2000 (Public Law 106-390) and the implementing regulations set forth by the Interim Final Rule published in the Federal Register on February 26, 2002 (44 CFR §201.6). Hereafter, these requirements and regulations will be referred to collectively as the Disaster Mitigation Act, or DMA. While the act emphasized the need for mitigation plans and more coordinated mitigation planning and implementation efforts, the regulations established the requirements that LHMPs must meet in order for a local jurisdiction to be eligible for certain federal disaster assistance and hazard mitigation funding under the Robert T. Stafford Disaster 791
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Relief and Emergency Act (Public Law 93-288). Because the Stanislaus County planning and response area is subject to many kinds of hazards, access to these programs is vital. As a result, the County and their participating jurisdictions must complete a comprehensive plan update every five years. For the current plan update, Stanislaus County completed the update as part of a multi-jurisdictional planning process in 2021-2022 to bring the MJHMP into compliance with recent legislation related to climate change and to address new human-health and natural hazards and emerging concerns. The Stanislaus County 2017 LHMP was initially approved by FEMA on January 12, 2006, updated, and approved by FEMA on July 20, 2011, updated again on July 13, 2017.

Information in this plan will be used to help guide and coordinate mitigation activities and decisions for local land use policy in the future. Proactive mitigation planning will help reduce the cost of disaster response and recovery to the community and its property owners by protecting critical community facilities, reducing liability exposure, and minimizing overall community impacts and disruption. The Stanislaus County planning area has been affected by hazards in the past and is thus committed to reducing future disaster impacts and maintaining eligibility for federal funding.

This hazard mitigation plan identifies resources, information, and strategies for reducing risk from natural hazards. Elements and strategies in the plan were selected because they meet a program requirement and because they best meet the needs of the planning partners and their citizens. One of the benefits of multijurisdictional planning is the ability to pool resources and eliminate redundant activities within a planning area that has uniform risk exposure and vulnerabilities. FEMA encourages multi-jurisdictional planning under its guidance for the DMA. This plan will help guide and coordinate mitigation activities throughout the planning area. The plan was developed to meet the following objectives:
• Meet or exceed requirements of the DMA.
• Enable all planning partners to use federal grant funding to reduce risk through mitigation. • Meet the needs of each planning partner as well as state and federal requirements. • Create a risk assessment that focuses on Stanislaus County hazards of concern. • Integrate a consequence analysis to meet Emergency Management Accreditation Program (EMAP) standards (ANSI/EMAP EMS 5-2019).
• Update the risk assessment with a consequence analysis that assesses the risk and vulnerability of people, property, the environment, and its own operations form these hazards. • Conduct a consequence analysis for natural and non-natural hazards to consider the impacts on the public; responders; continuity of operations (including the delivery of services); property, facilities, and infrastructure; environment, economic conditions of the jurisdiction; and public confidence in the jurisdiction’s governance.
• Create a single planning document that integrates all planning partners into a framework that supports partnerships within the County and puts all partners on the same planning cycle for future updates. • Meet the planning requirements of FEMA’s Community Rating System (CRS), allowing planning partners that may choose to participate in the CRS program to enhance their CRS classifications. • Coordinate existing plans and programs so that high-priority initiatives and projects to mitigate possible disaster impacts are funded and implemented.

1.8 Multi-Jurisdictional Planning
All citizens and businesses of Stanislaus County are the ultimate beneficiaries of this MJHMP. The plan reduces risk for those who live in, work in, and visit the County. It also provides a viable planning framework for all foreseeable natural hazards that may impact the County. Participation in development of the plan by key stakeholders in the County helps ensure that outcomes will be mutually beneficial. The resources and background information in the plan are applicable countywide, and the plan’s goals and recommendations can lay groundwork for the development and implementation of local mitigation activities and partnerships.

The Stanislaus County MJHMP is a multi-jurisdictional plan that geographically covers everything within Stanislaus County’s jurisdictional boundaries (hereinafter referred to as the planning area). Unincorporated Stanislaus County and the following jurisdictions participated in the 2021 update planning process:
• Stanislaus County
• City of Ceres
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• City of Hughson
• City of Modesto
• City of Newman
• City of Oakdale
• City of Patterson
• City of Riverbank
• City of Turlock
• City of Waterford
• County Office of Education
The nine cities and County Office of Education are new participating jurisdictions as part of the 2021-2022 MJHMP update process. While this is the first HMP for some of the jurisdictions, all of the jurisdictions were invited to participate in the 2006, 2010, and 2017 planning processes; however not all jurisdictions formally participated and developed annexes to the County’s MJHMP at the time. For example, only some of the jurisdictions adopted an Annex to the 2010 MJHMP (i.e., City of Riverbank). Further, the 2017 LHMP only covered Stanislaus County. This 2021-2022 MJHMP update process covers each participating jurisdiction and includes 10 annexes.

1.9 Plan Organization
The sections that comprise the County’s MJHMP include:

Executive Summary and Prerequisite – This section includes the executive summary of the MJHMP and addresses the formal adoption of the plan by each governing body to demonstrate the commitment of the community and elected officials to the County's goal of becoming disaster resistant.

Section 1: Introduction – This section describes the purposes of the MJHMP update, benefits of hazard mitigation planning, the federal and state regulatory requirements, and the background of the County’s hazard mitigation planning process.

Section 2: Community Profile and Capability Assessment – This section provides the history and background of the County, including population trends and the demographic and economic conditions that have shaped the area. This section also includes the County’s capability assessment.

Section 3: Planning Process – This section identifies the planning process, the Planning Committee members, the meetings held as part of the planning process, documents the outreach efforts, and the review and incorporation of existing plans, reports, and other appropriate information.

Section 4: Hazard Identification, Risk Assessment (HIRA), and Consequence Analysis –This section describes the process through which the Planning Committee and our local partners identified, screened, and selected the hazards to be profiled. The hazard analysis includes the description, location, extent, and probability of future events for each hazard. This section also includes a Consequence Analysis to align with EMAP standards. The Consequence Analysis covers all hazards and considers the impact on the following assets: public; responders; continuity of operations including continued delivery of services; property, facilities, and infrastructure; environment; economic condition of the jurisdiction; and public confidence in the jurisdiction’s governance.

Section 5: Mitigation Strategy – The mitigation strategy section provides a plan for reducing the potential losses identified in the vulnerability analysis. Mitigation goals and potential actions to minimize the risks and losses associated with each hazard will be described along with a strategy for implementation.

Section 6: Implementation and Maintenance – This section describes the method and schedule for monitoring, evaluating, and updating the plan to ensure it remains an active and applicable document.

Section 7: Plan Adoption – This section includes the plan adoption documentation and process for integrating the plan by reference into the County’s General Plan Safety Element.

Section 8: References – This section lists the sources cited in the plan. 793
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1.10 Appendices
• Appendix A: Hazard Mitigation Planning Committee
• Appendix B: Planning Process Documentation
• Appendix C: Approval and Adoption Documentation
• Appendix D: Mitigation Categories and Alternatives
• Appendix E: Annual Progress Meeting Agenda and Report Template • Appendix F: Outreach Strategy

1.11 Annexes
• Annex A: City of Ceres
• Annex B: City of Hughson
• Annex C: City of Modesto
• Annex D: City of Newman
• Annex E: City of Oakdale
• Annex F: City of Patterson
• Annex G: City of Riverbank
• Annex H: City of Turlock
• Annex I: City of Waterford
• Annex J: County Office of Education
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2 COMMUNITY PROFILE AND CAPABILITY ASSESSMENT

2.1 History
Stanislaus County is located in the heart of California’s Central Valley, (see Figure 2-1) within 90 minutes of the San Francisco Bay Area, the Silicon Valley, Sacramento, the Sierra Nevada Mountains, including Yosemite National Park, and California’s Central Coast. It is also within a five-hour drive of Los Angeles.

Two of California’s major north-south routes (Interstate 5 and Highway 99) intersect the area making the County one of the dominant logistics center locations on the west coast.

The County is bordered on the north by San Joaquin County, the east by Mariposa, Tuolumne, and Calaveras counties, the south by Merced County, and the west by Alameda and Santa Clara counties.

Established in 1854, Stanislaus County’s total land area is 1,494 square miles. The County seat is the City of Modesto, located near the center of the County.

Figure 2-1 Stanislaus County Planning Area
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2.2 Geography and Climate
The mild Mediterranean climate makes Stanislaus County one of the best agricultural areas in the world, positioning it as a global center for agribusiness. The County averages approximately twelve inches of rainfall each year and experiences a full spectrum of the seasons. Temperatures range from an average low of 38 degrees Fahrenheit in the winter, to an average high of 85 degrees Fahrenheit during the spring and fall, and to average highs in the 90’s during the summer months. Table 2-1 lists the average high and low temperatures by month and associated average rainfall.

Table 2-1 Temperature and Rainfall Averages for Stanislaus County Average High/Low Temperature Average Rainfall
January 55°/40° F (13°/4.5° C) January 2.6 inches
August 94°/62° F (34.2°/16.8°C) August.05 inches
Annual 76°/52.2° F (24.4°/10.6° C) Annual 13.2 inches
Source: U.S. Climate Data 2021

2.3 Rivers
There are four major rivers in Stanislaus County. Three of these rivers, the Stanislaus, Calaveras, and Tuolumne Rivers, run east to west, with the Calaveras River crossing the tip of the northeast County border.

The fourth, the San Joaquin River, runs southeast to northwest. Dry Creek also runs east to west, and then merges with the Tuolumne River in Modesto. There are no flow control systems on Dry Creek. Rainfall and runoff in the eastern portion of the County directly affect this creek. The County also has three major reservoirs: Modesto, Woodward, and Turlock.

2.4 Population
Stanislaus County has nine municipalities: the cities of Ceres, Hughson, Modesto, Newman, Oakdale, Patterson, Riverbank, Turlock, and Waterford. Additionally, there are thirteen unincorporated communities within the County and large expanses of state- and federally-owned lands such as parks, wildlife areas and other public lands. As the County seat, the City of Modesto has the largest population. The United States Office of Management and Budget has designated Stanislaus County as the Modesto, CA Metropolitan Statistical Area (MSA). The U.S. Census Bureau ranked the Modesto, CA \MSA as the 104th most populous MSA of the United States as of 2020. Figure 2-2 breaks down the population of the County by cities and unincorporated areas.
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Figure 2-2 Stanislaus County Population by City
Source: Source: 2015-2019 American Community Survey (ACS), 5-year estimates, U.S. Census Bureau Table 2-2 lists the estimated population increases in Stanislaus County from 2020 through 2021 organized by city and the unincorporated area.

Table 2-2 Estimated Population Increase 2020 – 2021
County/City 2017 Census 2021 Estimate Population % Change Stanislaus 535,684 555,968 3.8
Ceres 47,650 48,901 2.6
Hughson 7,295 7,303 0.1
Modesto 210,166 219,294 4.3
Newman 10,951 11,962 9.2
Oakdale 22,256 23,237 4.4
Patterson 21,497 23,304 8.4
Riverbank 24,047 25,189 4.7
Turlock 71,906 74,820 4.1
Waterford 8,786 8,944 1.8
Unincorporated 111,130 113,014 1.7
Source: Population Estimates for Cities, Counties, and the State January 1, 2021, Demographic Research Unit, California Department of Finance; 2013 – 2017 American Community Survey (5-year estimates) According to the Total Population Projections, 2010 – 2060, prepared by the State of California Department of Finance’s (DOF) Demographic Research Unit, as of July 1, 2021, the estimated total population for Stanislaus County was 561,951. As shown in Figure 2-3, the DOF Demographic Research Unit projects the population for Stanislaus County in 2060 to be 680,311. This represents a 21% increase in population over the next 40 years.

Ceres
9%
Hughson
1%
Modesto
39%
Newman
2%
Oakdale
4%
Patterson
4%
Riverbank
5%
Turlock
13%
Waterford
2%
Unincorporated
21%
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Figure 2-3 Stanislaus County Projected Population Growth Source: Total Population Projections, 2010 – 2060, California and Counties – 2019, Demographic Research Unit, California Department of Finance
Table 2-3 highlights the County’s population characteristics in 2019.

Table 2-3 Stanislaus County Population Characteristics – 2019: ACS 5-Year Estimates Population Number Percent
Total Population 543,194 100%
Sex and Age
Male 268,881 49.5%
Female 274,313 50.5%
Median Age (years) 34.1 N/A
17 and Under 147,206 27.1%
65 Years and Older 69,529 12.8%
Disabled 71,158 13.1%
Total Households 173,898
Persons per household 3.09 N/A
Median household income $60,704 N/A
Persons in Poverty, Percent 82,022 15.1%
Language Other than English Spoken at Home 233,030 42.9% Education
High School Graduate or Higher, Percent
(25 years and over) 271,121 78.9%
Bachelor’s Degree or Higher 58,760 17.1%
Stanislaus County School Enrollment (K-12) 108,614 20%
Source: U.S. Census Bureau, 2015-2019 ACS
The median resident age for Stanislaus County residents is 34.1. Approximately 12.8% of the population is over the age of 65. The disability status of the civilian non-institutionalized population is 13.1%. Of the

13.4%, 8.2% are under 18 years, 51.4% are 18-64 years, and 40.5% are 65 years and older. For the total population five years and older, 57.1% speak English only in the home and 42.9% speak a language other than English.
560,000
580,000
600,000
620,000
640,000
660,000
680,000
2021 2025 2030 2035 2040 2045 2050 2055 2060
Estimated Population Projection
Year
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Table 2-4 summarizes the estimated population statistics by race based on the U.S. Census ACS data.

Table 2-4 2015 – 2019 American Community Survey County Population by Race Estimated Population 543,194 100%
Hispanic or Latino 251,259 46.3%
White 227,369 41.9%
Black 15,311 2.8%
American Indian and Alaska Native 2,481 0.5%
Asian 29,284 5.4%
Native Hawaiian and Other Pacific Islander 3,625 0.7%
Some Other Race 747 0.1%
Two or More Races 13,118 2.4%
Source: U.S. Census Bureau, 2015-2019 ACS
The 2015-2019 ACS (5-year estimates) provided by the California DOF shows that the total population of Stanislaus County is comprised of 46.3% Hispanic or Latino, 41.9% White, 2.8 % Black, 0.5% American Indian and Alaska Native, 5.4% Asian, 0.7% Native Hawaiian and Other Pacific Islander, 0.1% some other race, and 2.4% two or more races.

2.5 Economy
Stanislaus County’s productive soils, long growing seasons, and extensive transportation network combine to make a successful farm and business region. Agriculture is the County’s core industry with the value of agricultural commodities produced in 2020 valued at $3,476,093,000. This represents a 3% decrease from the 2019 gross production value and is primarily attributed to the COVID-19 pandemic and the 47-day SCU Lightening Complex fire that burned significant rangeland on the westside of the County. Figure 2-4 includes a bar graph that shows the value of the top agricultural commodities in Stanislaus County like fruit and nut crops followed by livestock and poultry products.

Figure 2-4 Stanislaus County Top Agricultural Commodities: 2019 – 2020 Dollar Value Source: Stanislaus County Agricultural Crop Report 2020.

According to the Stanislaus County Comprehensive Economic Development Strategy 2021 – 2026, Stanislaus County ranks high in Capital-Intensive Manufacturing. Food and Beverage Manufacturing has 0 200,000,000
400,000,000
600,000,000
800,000,000
1,000,000,000
1,200,000,000
1,400,000,000
1,600,000,000
Value in $
Category
2020 2019
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long been a well-performing industry for the County. The manufacturing industry also continues to be an important employer in Stanislaus County. The top ten major manufacturing employers in 2020 are listed in Table 2-5.

Table 2-5 Major Manufacturing Employers – 2020
Employer Description Employees*
E & J Gallo Winery 6,000
Foster Farms Food Processing 2,000
Del Monte Foods Food Processing 1,500
Stanislaus Food Products Canning 1,500
Con Agra Food Processing 1,000
Frito-Lay Food Manufacturing 650
Blue Diamond Growers Nut Processor 500
Pacific Southwest Containers Container Manufacturing 451 Bronco Wine Winery 450
Siligan Containers Container Manufacturing 388
Source: Stanislaus County Comprehensive Economic Development Strategy 2021 – 2026 The top ten non-manufacturing employers in Stanislaus County for 2020 are listed in Table 2-6.

Table 2-6 Major Non-Manufacturing Private Employers in Stanislaus County – 2020 Employer Description Employees
Save Mart Supermarkets Retail Grocery 10,500
Stanislaus County County Government 3,887
Modesto City Schools School District 3,200
Doctors Medical Center Health Care 2,600
Turlock Unified School District School District 2,000
Memorial Medical Center Health Care 2,000
Ceres Unified School District School District 1,500
Stanislaus County Office of Education Education District 1,130 City of Modesto City Government 1,200
CSU Stanislaus Public University 1,000
Source: Stanislaus County Comprehensive Economic Development Strategy 2021 – 2026

2.6 Unemployment Rate Comparison
The County’s unemployment rate rose to 16.8% in 2013, the highest figure recorded in 10 years, up from

12.5% in 2010, according to the ACS 5-year estimates. Since 2014, unemployment rates dropped to 9.1% in 2019, which was a decrease from a 10.5% unemployment rate in 2018. At this time, Stanislaus County’s unemployment rate is higher than the nationwide and California rates, which are at 5.3% and 6.1%, respectively. Figure 2-5 compares the unemployment rates among the County, State, and surrounding counties in the Central Valley.
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Figure 2-5 Unemployment Rates: Stanislaus County versus State and Surrounding Counties Source: American Community Survey 5-Year Estimates

2.7 Commuters
Unemployment rates can affect the number of commuters who must travel outside Stanislaus County for work. Based on a May 2017 report by the U.S. Census Bureau, the State of California Employment Development Department estimates that 28,612 workers commuted to work from other counties to Stanislaus County and 44,557 workers commuted from Stanislaus County to other counties, as shown in Figure 2-6. These estimates are based on the 152,239 total workers estimated to live and work in Stanislaus County.
4%
6%
8%
10%
12%
14%
16%
18%
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
Unemployement Rate
Year
Unemployment Rate Comparison
US California Merced San Joaquin Stanislaus
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Figure 2-6 Stanislaus County to Surrounding Counties Commuter Patterns in 2020 Source: Stanislaus County Commuter Study 2020
According to 2020 Stanislaus County Commuter Study, 24% of Stanislaus County residents work outside the County. Over half of these commuters travel to the Bay Area, specifically Alameda County (25%), Santa Clara County (13%), and Contra Costa County (5%). The other portion travels to San Joaquin County.

2.8 Housing
In 2020, median home values in Stanislaus County had reached $352,968, and by 2021, they had increased by 13.1% to $399,195. Although median home prices in Stanislaus County have increased, the County still lags behind four of the five comparison counties and the State. San Joaquin County had the largest increase with an 15.7% increase in median home values between 2020 and 2021. Figure 2-7 compares the median home prices in Stanislaus County to the State and several of the surrounding counties. 802
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Figure 2-7 Comparison of Median Home Prices in Stanislaus County and Surrounding Counties
Source: Counties’ data is from National Associate of Realtors; State data is from Norada Real Estate Investments.

2.9 Housing and Development Trends
Within the unincorporated area of Stanislaus County there has been no significant development since the previous plan was adopted in 2017. The exception to this is the planned community on the western side of the County called Diablo Grande near the City of Patterson. The community was largely developed in the 1990s, but the community was never built out due to financial issues and the housing crisis. In 2017, the County approved a revised plan for the community that reduced the overall number of single-family and multi-family housing units; the community design also clustered the housing and limited development along the hillsides. This development was also evacuated during the SCU Lightning Complex Fire in 2020. Other development within the County has mainly occurred within the nine cities.

Stanislaus County’s Planning and Community Department tracks issued single-family residential construction permits as a way of monitoring the home construction, building materials and construction employment sector. After reaching a low of 413 in 2015, issued permits steadily increased to 759 permits issued in 2018. In 2019, issued permits decreased to 699 permits. These building permit trends are shown in Figure 2-8. The County’s Planning and Community Development Department also issued 145 new singlefamily dwelling unit permits from 2016 through 2020; these permits include new dwelling units, not modifications or improvements to existing single-family residential uses (Stanislaus County 2021).

Alameda
County
Merced
County
Sacramento
County
San Joaquin
County
Santa Clara
County
Stanislaus
County California
2020 841,236 289,863 405,448 398,574 1,126,389 352,958 711,300 2021 854,696 329,284 459,373 461,150 1,187,214 399,195 798,440 -
200,000
400,000
600,000
800,000
1,000,000
1,200,000
Median Home Prices
2020 2021
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Figure 2-8 Stanislaus County Single-Family Building Permit Trends: 2013 – 2019 Source: United States Census Bureau
NOTE: The single-family building permit trends was derived from the US Census Bureau and does not include the County Community Development Department issued permit data.

2.10 Transportation
According to the California Department of Transportation (Caltrans), in 2019 Stanislaus County had 188 miles of State Highways, 1606 miles of county roads, 1,292 miles of city roads, and 383 bridges. There were 525,565 registered vehicles, including 327,336 registered automobiles, and 117,116 registered trucks.

The County had 355,857 licensed drivers. Among all the workers who are 16 years and over (230,975),

93.7% commuted by driving alone or carpooling in a car, truck, or van.

2.11 Highways/Roads/Bridges
State Highways 99, 108/120, 33, 132, and Intestate 5 (I-5) are major transportation routes through the County. Highways 99, 33 and I-5 run north – south and Highways 108/120 and 132 run east – west. These major highway/freeway routes would be highly utilized by both County residents and tourists as possible evacuation routes.

Public roadways and bridges within Stanislaus County are owned and maintained by Caltrans, Stanislaus County Public Works Department, and the nine city Public Works Departments. A high potential exists for road closures due to flooding or earthquakes. Parts of the County may become isolated for a period of time when these conditions exist. While most secondary roads are paved, there are still a number of unpaved public roads within the County.

2.12 Airports
One joint County/City of Modesto operated airport is in Stanislaus County. The Modesto City-County-Harry Sham Field Airport’s runways are 5904 feet and 3464 feet, respectively. The airport operates 24 hours daily, although the tower is closed at night. It is capable of multiple engine propeller aircraft or jet aircraft, as large as a 737-400. There are an additional four airports in Stanislaus County: Oakdale Municipal Airport (2400 foot east-west runway), Turlock Municipal Airport (2985 foot north-south runway), Patterson Airport (2500 foot north-south runway) and the Crows Landing Naval Air Station. Both the Patterson Airport and the Crows Landing Naval Air Station are not functional airports. In Patterson, the runway and tarmac are leased by a private company and a landing area is used for medical helicopters. 0 100
200
300
400
500
600
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800
2013 2014 2015 2016 2017 2018 2019
Number of Permits
Year
Stanislaus County Single-Family Building Permits
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2.13 Railroads
The Union Pacific (UP) and Burlington Northern Santa Fe (BNSF) Railroads are the freight lines serving Stanislaus County. Both have tracks running north – south in the County. Amtrak passenger service is provided on the BNSF track with a passenger station located in eastern Modesto. Sierra Railroad serves between Tuolumne County and the City of Oakdale in Stanislaus County. Also, the Modesto and Empire Traction Company (M&ET), a short line freight railroad, provides interconnection services between UP and BNSF Railroads, as well as serving the industrial hub of the County. M&ET operates 5 miles of yard main track and an additional 48.7 miles of track within the Beard Industrial District.

2.14 Medical Facilities
Stanislaus County is home to Doctors Medical Center, Emanuel Medical Center, Memorial Medical Center, Kaiser Permanente Modesto Medical Center, Oak Valley Hospital, and Stanislaus Surgical Hospital. All but the Stanislaus Surgical Hospital provide Basic Emergency Services. These medical facilities are listed in Table 2-7. Only Doctor’s Medical Center and Memorial Hospital provide Level II Trauma Services.

The County also has approximately 20 licensed Nursing and Rehabilitation Care Centers that can coordinate with hospitals to alleviate surge during an incident. In addition, Stanislaus County Health Services Agencies has medical offices in Ceres, Hughson, Modesto, and Turlock, and provides a variety of medical services throughout the County.

Table 2-7 Medical Facilities in Stanislaus County
Hospital Number of Staffed Beds ER Services Trauma
Services
Doctor’s Medical Center, Modesto 461 Basic Emergency Level II Emanuel Medical Center, Turlock 209 Basic Emergency None Kaiser Permanente Modesto Medical
Center, Modesto 140 Basic Emergency None
Memorial Hospital, Modesto 423 Basic Emergency Level II Oak Valley Hospital, Oakdale 150 Basic Emergency None
Stanislaus Surgical Hospital, Modesto 23 None None
Source: California Office of Statewide Health Planning and Development

2.15 Arts, Entertainment and Recreation
Stanislaus County offers a variety of arts, entertainment, and recreation opportunities. The County is home to a vibrant arts community with the world class Gallo Center for the Arts, a symphony orchestra, and abundant visual and performing arts. Notable places of interest include the McHenry Mansion, McHenry Museum, the State Theater in Modesto, the Carnegie Arts Center in Turlock, and the Assyrian Cultural Center in Ceres.

For sports enthusiasts, John Thurman Field, located in the City of Modesto, is home to the Modesto Nuts, a minor league baseball team, aligned in the Low-A West North Division as an affiliate of the Seattle Mariners.

Stanislaus County maintains five regional parks, 22 neighborhood parks, eight special interest parks, 9 miscellaneous parks and open space assets, community parks, two off-highway vehicle parks, five fishing access points along rivers and lakes, and two swimming pool. Day use and camping is available at Frank Raines Regional Park and La Grange Regional Park, and camping, boating and other recreational activities are available at the Modesto Reservoir Regional Park and Woodward Reservoir Regional Park.

2.16 County’s Mitigation Capabilities
The following section assesses the County’s and each participating jurisdictions’ existing capabilities to pursue hazard mitigation. The capability assessment analyzes Stanislaus County’s capabilities that can be leveraged to mitigate hazards. Combining the risk assessment and consequence analysis with the mitigation capability assessment results in the County’s “net vulnerability” to disasters, and more accurately focuses the goals, objectives, and proposed actions of this plan. 805
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The Hazard Mitigation Planning Committee (HMPC) used a two-step approach to conduct this assessment for the County and jurisdictions. First, an inventory of common mitigation activities was made using a matrix.

The purpose of this effort was to identify policies and programs that were either in place, needed improvement, or could be undertaken if deemed appropriate. Second, the HMPC conducted an inventory and review of existing policies, regulations, plans, and programs to determine if they contributed to reducing hazard-related losses or if they inadvertently contributed to increasing such losses.

This assessment is divided into four sections: regulatory mitigation capabilities; administrative and technical mitigation capabilities; fiscal mitigation capabilities; and mitigation outreach and partnerships. Additional information on jurisdiction capabilities can also be found in the participating jurisdiction’s annexes.

2.16.1 Regulatory Mitigation Capabilities
The regulatory and planning capabilities listed in Table 2-8 outline planning and land management tools typically used by local jurisdictions to implement hazard mitigation activities and indicate those that are in place in Stanislaus County.
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Table 2-8 Regulatory Mitigation Capabilities
Regulatory Tool
(ordinances,
codes, plans)
Stanislaus
County Ceres Hughson Modesto Newman Oakdale Patterson Riverbank Turlock Waterford Office of Education General plan Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/A Zoning ordinance Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/A Subdivision
ordinance Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/A
Growth
management
ordinance
No No No No No No No No No No N/A
Floodplain
ordinance Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/A
Other special
purpose
ordinance (storm
water, steep
slope, wildfire)
Yes Yes Yes Yes Yes, Yes Yes Yes Yes Yes N/A
Building code Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/A Fire department
ISO rating Yes
Yes,
Rating
3 Yes,
Rating
4/8B
Yes
Rating 2
Yes,
Rating 3
Yes,
Rating
3/6
Yes,
Rating
2/2Y
4/4Y Yes,
Rating 2 4/4Y See Note 1
Erosion or
sediment control Yes No No Yes Yes No Yes Yes Yes No N/A Storm water
management
program
Yes Yes No Yes Yes Yes Yes Yes Yes No N/A
Site plan review
requirements Yes Yes Yes Yes Yes Yes Yes No Yes N/A
Capital
improvements
plan
Yes No No Yes No No Yes Yes Yes No N/A
Economic
development plan Yes Yes No No No No No Yes Yes No N/A
Local EOP Yes No No No No No No Yes No Yes N/A
Other special
plans N/A N/A n/a No No N/A N/A N/A N/A N/A N/A
Flood insurance
study or other
engineering study
for streams
Yes Yes Yes Yes Yes Yes Yes No Yes Yes N/A
Elevation
certificates Yes Yes Yes No Yes N/A Yes Yes No No N/A
Source: Hazard Mitigation Planning Committee
NOTES: 1 – New K-12 school construction and modernization projects must submit site plans for review through the Division of State Architect’s (DSA) process. 807
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2.16.2 Related Plans and Regulations
Stanislaus County General Plan, 2015
The General Plan guides the physical development, preservation, and conservation of areas within the unincorporated areas of the County. The General Plan covers the entire Stanislaus County and discusses various subjects comprehensively. The General Plan plans for the long term – ranging from 15 to 30 years.

The General Plan identifies adopted goals, policies and implementation that govern the development in the County. In addition, the General Plan includes a Land Use Diagram for all areas within its jurisdiction.

The General Plan is further carried out by the following tools:
• Specific and Community Plans
• Zoning Ordinance
• Subdivision Ordinance
• Approval of Individual Development Applications
• The County's five-year Capital Improvement Program (CIP) • Environmental Assessment and Review Procedures under the California Environmental Quality Act (CEQA)
The County’s General Plan includes the seven mandatory elements: the Land Use Element, Circulation Element, Conservation/Open Space Element, Noise Element, Safety Element, 2015-2023 Housing Element, and the Agricultural Element. The Safety Element contains the goals and policies that address natural and human-caused hazards in the County.

Safety Element
The Safety Element policies focus on the protection of the community from any unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure; tsunami, seiche, and dam failure; slope instability leading to mudslides and landslides, subsidence; liquefaction; and other geologic hazards known to the legislative body; flooding; military installations; and wildland and urban fires. The County is susceptible to all the main safety hazards with the exception of tidal waves associated with a tsunami, military installations, and major hazardous waste disposal sites. There are also no special airspace and aircraft training routes in Stanislaus County. The County’s Safety Element, therefore, focuses its goals, policies, and implementation programs on seismic and geologic hazards, dam inundation, flood hazards, fire hazards, hazardous materials, airports, and other safety hazards related to unprotected canals, insufficient safety lighting, antennas, communication towers, and wind generation facilities near agricultural areas. Additionally, the Safety Element integrates a brief section on climate vulnerability and climate adaptation information. The Safety Element also fully incorporates the County’s 2010 MJHMP by reference to meet the requirements under California Government Code Section 65302(g)(4). During the 2022-2027 MJHMP update, the County OES and Planning and Community Development Department collaborated so that the forthcoming Safety Element update would complement and be consistent with the efforts already underway associated with the MJHMP, such as the climate-related hazards profiled and the other climate change considerations addressed in the risk and vulnerability assessment.

Stanislaus County Emergency Operations Plan, 2021
The Emergency Operations Plan (EOP) “Basic Plan” updated in 2021 addresses the planned response to extraordinary emergency situations associated with natural or human-caused disasters, technological incidents, and national security emergencies in or affecting Stanislaus County. This EOP focuses on operational concepts and would be implemented relative to large-scale disasters which can pose major threats to life, property and the environment requiring unusual emergency responses.

This EOP establishes the emergency management organization required to mitigate any significant emergency or disaster affecting Stanislaus County. It also identifies the roles and responsibilities required to protect the health and safety of Stanislaus County residents, public and private property, and the environmental effects of natural, man-made, and technological emergencies and disasters. The EOP further establishes the operational concepts associated with a field response to emergencies, the Stanislaus County Emergency Operations Center (EOC) activities, and the recovery process. 808
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In addition, the EOP is based on the National Incident Management System (NIMS) and its component parts, along with the California Standardized Emergency Management System (SEMS), including the five functional areas of the Incident Command System (ICS): Management/Command, Operations, Planning, Logistics, and Finance/Administration. The 2021 EOP is organized into the Basic Plan, Emergency Support Functions, and annexes that contain general and specific information related to County emergency management operations.

Disaster Council and Emergency Services Ordinance, (County Code Chapter 2.52) The purpose of this chapter is to provide for: 1) The preparation and effectuation of plans to protect persons and property in this County in emergencies; 2) the creation, direction, and operation of the County emergency organization; and 3) the coordination of the County’s emergency services and functions with those of other public and private entities, organizations, and persons. (Ord. CS 1288 §1, 2020).

Building Code (County Code Chapter 16.05)
The County adopted the California Building Code, as published by the International Code Council, 2019 Edition, Part 2, Volume 1, Chapter 1, Division II Scope and Administration and Part 2, Volume 2, Appendix “C” “Group U – Agricultural Buildings,” Appendix “H” “Signs,” and Appendix “J” “Grading.” The code updates are adopted by reference and incorporated to also include the California Building Code, 2019 Edition, Chapter 1, Division II requirements. Section C101.4 in the County Code is also added to cover earthquake loads for agricultural structures.

Floodplain Management Ordinance (County Code Chapter 16.50) The purpose and objective of these regulations and the flood load and flood resistant construction requirements of the building codes are to promote the public health, safety and general welfare and to minimize public and private losses due to flood conditions in specific flood hazard areas through the establishment of comprehensive regulations for management of flood hazard areas, designed to:
• Minimize unnecessary disruption of commerce, access, and public service during times of flooding. • Require the use of appropriate construction practices in order to prevent or minimize future flood damage.
• Manage the alteration of natural floodplains, stream channels and shorelines to minimize the impact of development on the natural and beneficial functions of the floodplain. • Manage filling, grading, dredging, mining, paving, excavation, drilling operations, storage of equipment or materials, and other development which may increase flood damage or erosion potential. • Prevent or regulate the construction of flood barriers which will divert floodwater or increase flood hazards.
• Contribute to improved construction techniques in the floodplain. • Minimize damage to public and private facilities and utilities. • Help maintain a stable tax base by providing for the sound use and development of flood hazard areas. • Minimize the need for rescue and relief efforts associated with flooding. • Ensure that property owners, occupants, and potential owners are aware of property located in flood hazard areas.
• Minimize the need for future expenditure of public funds for flood control projects and response to and recovery from flood events.
• Meet the requirements of the National Flood Insurance Program for community participation as set forth in Title 44 CFR, Section 59.22. (Ord. CS 1301 §2, 2021).

Stanislaus County Extreme Heat Contingency Plan (2018)
The 2018 Stanislaus County Extreme Heat Contingency Plan, which functions as a supporting document to the Stanislaus County EOP and the State of California Contingency Plan for Excessive Heat Emergencies. The Extreme Heat Contingency Plan outlines the actions that will be taken by the Operational Area and local government when an extreme heat event is anticipated, is in the process of occurring, or has occurred. This plan is designed to facilitate preparedness for, and response to, future excessive heat 809
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events. It also provides guidance for local government and non-governmental organizations in the preparation of their heat emergency response plans and other related activities.

The plan describes Operational Area coordination during heat-related emergencies and provides guidance for Stanislaus County government, other governmental agencies, local businesses, community-based organizations, and faith-based organizations, in the preparation for, and response to, emergency incidents of extreme heat. The plan recognizes the need for the County of Stanislaus to: 1) identify when the health of populations and/or subpopulations of local residents may be threatened by extreme heat conditions; 2) communicate with the public to convey information about resources available for protection against extreme heat emergencies in time to allow for preparations to be made; 3) communicate and coordinate with State and local agencies; 4) mobilize resources and initiate actions to augment local resources as needed; and 5) employ the SEMS/NIMS in organizing a response to an extreme heat emergency. The plan also recognizes three phases of activation: 1) pre-seasonal readiness, 2) excessive heat watch/advisory, and 3) excessive heat warning. Specific actions are associated with each activate phase.

Modesto Subbasin Groundwater Sustainability Plan (2022) The Sustainable Groundwater Management Act (SGMA) requires the formation of local Groundwater Sustainability Agencies (GSAs) to oversee the development and implementation of Groundwater Sustainability Plans (GSPs). The goal of the GSPs is to achieve sustainable management of the State’s groundwater basins.

In 2017, member agencies of the Stanislaus and Tuolumne Rivers Groundwater Basin Association (STRGBA) – City of Modesto, Modesto Irrigation District, City of Oakdale, Oakdale Irrigation District, City of Riverbank, City of Waterford, and Stanislaus County – formed as a GSA. STRGBA GSA has the authority and responsibility to manage the groundwater basin. Many groundwater basins in the San Joaquin Valley have experienced heavy groundwater pumping – especially during the recent drought. Several are now in a condition of critical overdraft. The Modesto basin is not considered to be critically over drafted, but since most of the cities within the basin rely solely on groundwater, the Modesto basin is considered a highpriority basin. Due to that designation, SGMA requires that STRGBA adopts and begins implementation of a GSP by January 31, 2022.

East Stanislaus Integrated Regional Water Management Plan (IRWM) (2018) The East Stanislaus Regional Water Management Partnership (ESRWMP) was formed in 2011 to create the East Stanislaus Integrated Regional Water Management (IRWM) planning region and began the planning process. The purpose of an IRWM Plan is to: develop regional understanding; identify water resources solutions; reflect the regional needs; maximize benefits through integration of water management strategies; leverage regional resources through partnerships; be eligible for State funding through the IRWM grant program.

The Region's first IRWM Plan, created in 2013, was updated in 2018 to comply with State guidelines for IRWM Plans. The Region was awarded a Proposition 1 (Prop 1) planning grant of $147,000 from the California Department of Water Resources (DWR) in order to help fund the update process. The main purpose of the IRWM update is for the Region to identify projects and measures to be implemented to meet the Region's goals. In addition, the updated IRWM Plan will achieve the following objectives: comply with Prop 1 IRWM Guidelines and Plan Standards; address new legislation requirements, including Senate Bill (SB) 985, Assembly Bill (AB) 1249, and AB 52; and reflect current conditions and water resources-related work completed in the region since completion of the original IRWMP in 2013.

Mid San Joaquin River Regional Flood Management Plan (MSJR RFMP) (2017) The Mid San Joaquin River Regional Flood Management Plan (MSJR RFMP) was first developed in 2013 and 2014, and was updated in 2017, through the participation of a range of stakeholders primarily from Stanislaus County. This regional planning effort was created to give stakeholders the opportunity to develop a plan to reduce flood risks in the area from the confluence of the Merced and the San Joaquin Rivers to the confluence of the Stanislaus and the San Joaquin Rivers. The result of these efforts is a vision for a safer and more flood-resilient region that identifies challenges and opportunities for flood management and a prioritized list of actions for DWR to consider in their Central Valley Flood Protection Plan (CVFPP). The 810
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MSJR RFMP also identifies priority flood protection projects to be carried out by local sponsors. Millions of dollars have been raised by local sponsors from a variety of state, federal and other sources to make these projects a reality. The major focuses of MSJR RFMP include identifying new projects consistent with regional flood management goals and state polices, ways to improve regional coordination of flood management, and ways to improve regional resilience to evolving flood hazards.

Stanislaus County has numerous other plans, programs, and procedures in place that support hazard mitigation, public health and safety, hazardous materials management, and emergency operations. Some of these plans will also be incorporated by reference in this plan. These plans are listed below. • Alert & Warning Plan (Under development based on 2021 EOP Basic Plan) • Agriculture Response Plans
• Animal Disease Response Plan
• Area Plan for Emergency Response to Hazardous Materials Incidents in Stanislaus County • Avian Influenza Plan
• Care and Shelter Operations Plan
• Continuity of Operations/Continuity of Government Plans (COOP/COG) • Ethanol Facility Emergency Response Plan
• Extreme Cold and Freeze Plan
• Exotic Newcastle Disease (END) Task Force Plan
• Mass Fatality Plan
• Public Health All Hazards Emergency Operations Plan (AHEOP) • Stanislaus County Flood Emergency Operations Plan (RDs 2063, 2091, and 1602) • Stanislaus County Water Contingency Plan
• Stanislaus County Health Services Agency Crisis & Risk Communication Plan Related partner agency plans, some of which were reviewed to inform the MJHMP update risk assessment and mitigation strategies based on public availability, as they relate to flooding, drought and water supply, and PSPS events are listed below.
• American Red Cross Emergency Plan
• Cal State University Stanislaus EOP
• Department of Water Resources Directory of Flood Officials • Del Puerto Canyon Water District HMP
• East Side Mosquito-Borne Disease Guidance
• Merced Irrigation District EAP
• Modesto Irrigation District ERP
• Modesto Irrigation District Capacity and Energy Emergency Load Reduction Plan • Modesto and Empire Traction Company EOP
• Pacific Gas and Electric (PG&E) ERP
• Reclamation EAP
• San Luis Field Division EOP
• Tri-Valley Dam Project EAP
• Turlock Irrigation District EOP
• Turlock Irrigation District LHMP
• Turlock Lake EAP
• United Way Emergency Volunteer Center Operations Plan • Yosemite Community College District EOP

2.16.3 Administrative and Technical Mitigation Capabilities Table 2-9 below identifies the County personnel responsible for activities related to mitigation and loss prevention in Stanislaus County and the unincorporated areas. Many positions are full time and/or filled by the same person. A summary of technical resources follows. 811
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Table 2-9 Stanislaus County Administrative and Technical Mitigation Capabilities Personnel Resources Yes/No Department/Position
Planner/engineer with knowledge of land
development/land management practices
Yes Public Works Department
Engineer/professional trained in construction
practices related to buildings and/or infrastructure
Yes Public Works Department
Planner/engineer/scientist with an understanding
of natural hazards
Yes Public Works Department
Personnel skilled in Geographic Information
System (GIS)
Yes IT Central Department
Full time building official Yes Planning and Community Development Floodplain manager/Floodplain Administrator Yes Planning and Community Development Emergency manager No Office of Emergency Services
Grant writer Yes
Other personnel N/A
GIS Data Resources
(Hazard areas, critical facilities, land use, building
footprints, etc.)
Yes Stanislaus County Open Data
Warning Systems/Services
(Reverse 9-11, cable override, outdoor warning
signals)
Yes Office of Emergency Services
Other N/A
Source: Hazard Mitigation Planning Committee
Office of Emergency Services
The Office of Emergency Services (OES) Division is responsible for the day-to-day administration of Stanislaus County's disaster preparedness, mitigation, response, and recovery programs. OES develops and maintains the Stanislaus County LHMP and EOP and its associated annexes. OES also coordinates training, planning and exercises for first responders throughout the Stanislaus Operational Area.

StanEmergency.org keeps the public informed regarding fire safety, the recent COVID-19 pandemic, drought, extreme heat, Pacific Gas & Electric (PG&E) Public Safety Power Shutoffs and other hazard events.

StanAware is the Stanislaus County OES communications system that allows the public to be contacted directly in case of a large-scale emergency and keep local citizens informed in the event of an emergency or disaster.

StanAware utilizes the Everbridge Mass Notification System in use by many other government agencies, universities, and corporations. In the event of an emergency or disaster, residences and businesses within Stanislaus County can be contacted by telephone, text, or email with emergency alert information. The Stanislaus County OES can send a message regarding a situation to residences and businesses within a certain geographical area(s) that will contain special notice and instructions to be followed by citizens in the area. Emergencies are defined as situations or impending situations caused by forces of nature, accident or an intentional act that constitutes a danger of major proportions to life and property.

In the County’s 2017 LHMP, the County’s OES and its CEO were assigned 10 mitigation actions, including one for earthquake, three for dam incidents, two for flooding, and four to address multiple hazards.

Stanislaus County Fire Prevention Bureau
The Fire Prevention Bureau’s mission is to reduce the risk of fire; thus, protecting the lives, welfare, and economic vitality of the community. This is accomplished by providing a variety of services such as plan checking of new construction and tenant improvement projects, issuing permits for various operations involving fire safety, public fire safety education and enforcement of California Fire Code regulations. The Fire Prevention Bureau is composed of highly trained professionals consisting of the Fire Marshal, Fire Prevention Inspectors, and administrative assistants.
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Stanislaus County Fire Warden
The Fire Warden supports and coordinates all public fire services agencies in the County, with an emphasis on special fire districts. Activities include fire prevention and plan review, training, and fire and rescue mutual aid management. The Fire Warden's provides various responsibilities to the community, including the following:
• Serves as Stanislaus County's Fire and Rescue Operational Area Coordinator; • Coordination and assistance to fire departments and fire districts within Stanislaus County; • Serves as a liaison between local fire agencies and County departments; • Provides coordination efforts for local fire representatives to establish and implement operational level standards;
• Manages and directs the multi-jurisdictional "OES On-Call Duty Officer" program; • Manages the Fire Prevention Bureau;
• Provides operational level support to the multi-jurisdictional Arson Task Force; and • Manages the Operational Area's California Incident Command Certification System (CICCS).

Moreover, in the County’s 2017 LHMP, the County’s Fire Prevention Bureau and Fire Warden were assigned five mitigation actions. All five actions were to address wildfire hazard.

Stanislaus Consolidated Fire Protection District
The Stanislaus Consolidated Fire Protection District (SCFPD) was formed on March 3, 1995 as a result of Project 94, an exploratory project with the goal of providing the most effective and efficient method of public fire service delivery by reorganizing or combining fire service agencies. SCFPD serves a territory of 195 square miles within the original boundaries of the Riverbank Fire Protection District, Empire Fire Protection District, Waterford-Hickman-LaGrange Fire Protection Districts, and the Stanislaus County Fire. SCFPD serves a population of 50,000+ residents within its geographical boundaries. Within these boundaries SCFPD provides service to two cities (Riverbank & Waterford), and unincorporated areas within the County (Empire, La Grange, Hickman, Eastern Stanislaus County, Airport District, Gallo Winery, and Beard Industrial Tract).

Stanislaus County Planning and Community Development Department The Planning and Community Development Department promotes community and economic development by providing a diverse land use base focused on promoting and protecting local agriculture, enhancing community infrastructure and public services, and providing high quality, streamlined permit processing services.

The Planning and Community Development Department has three primary divisions. These divisions include 1) managing building permits, which include construction permits; floodplain administration; and abandoned and dangerous building abatement; 2) governing Community Development, including administrating Stanislaus Urban County Community Development Block Grant (CDBG) and Emergency Solutions Grant (ESG) fund administration; and housing programs (first-time home buyer and rehabilitation programs); and 3) Planning, which includes General Plan, Zoning Ordinance, and Subdivision Ordinance administration and implementation; California Land Conservation Act (Williamson Act) administration; and State Mining and Reclamation Act administration.

StanEmergency – “Beat the Heat” Webpage
StanEmergency maintains a webpage to offer insights regarding extreme heat prevention and preparedness, which includes tips to beat the heat, heat safety tips for pets, cooling zone locations, heat hotline and other relevant information available in English and Spanish. “Tips to beat the heat” information is shown in Figure 2-9.
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Figure 2-9 Publicly Available Information Regarding Extreme Heat on StanEmergency.org Source: StanEmergency.org

2.16.4 Fiscal Mitigation Capabilities
Table 2-10 identifies financial tools or resources that the County could potentially use to help fund mitigation activities.

Table 2-10 Stanislaus County Financial Capabilities
Financial Resources Accessible/
Eligible to Use
Comments/Has this been used for
mitigation in the past?
Community Development Block Grants Yes No. The County can use U.S. Department of Housing and Urban Development (HUD) funds
to acquire real property, relocate and demolish
structures in hazard areas, rehabilitate
residential and non-residential structures, and
construct or improve public facilities. Such
funding is available through the CDBG
Entitlement Communities Grants.

The Planning and Community Development
Department also administers the Stanislaus
Urban County CDBG and Emergency Solutions
Grant (ESG) funds.

Capital improvements project funding Yes No.

Authority to levy taxes for specific
purposes
Yes Has not been used. Must be approved by
voters.

Fees for water, sewer, gas, or electric
services, new development
Yes Has not been used. Services provided through
cities or districts and levied through property
assessments.
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Financial Resources Accessible/
Eligible to Use
Comments/Has this been used for
mitigation in the past?
Incur debt through general obligation
bonds
Yes No.

Incur debt through special tax bonds Yes Has not been used. Must be approved by twothirds voters.

Incur debt through private activities Yes Has not been used. Do not have any in place.

Federal Grant Programs (HMGP) Yes Has not been used. Various departments in Stanislaus County are eligible and will remain
eligible for HMA BRIC funding that focuses on
risk reduction and funding of public
infrastructure projects that increase the
County’s resilience to disasters.

The County is eligible for HMA FMA funding
that funds projects that reduce or eliminate the
risk of repetitive flood damage to buildings
insured by the NFIP.

The County is also eligible for Homeland
Security Preparedness Technical Assistance
Program funding. This funding source builds
preparedness technical assistance activities in
support of the four homeland security mission
areas related to prevention, protection,
response, and recovery.

Source: HMPC 2021

2.16.5 Other Mitigation Programs and Partnerships
Table 2-11 below summarizes some of the mitigation partnerships and education or outreach capabilities available to Stanislaus County.

Table 2-11 Stanislaus County Education and Outreach Capabilities Education & Outreach Yes/No Comments
Local Citizen Groups That
Communicate Hazard Risks Yes See below.

Firewise USA No There are currently no Firewise USA communities in the County.

StormReady Yes Both the County and California State University are participants.

Other
Source: HMPC 2021
American Red Cross: The American Red Cross identified several capability enhancements through collaboration with the County, cities, and fire departments of Stanislaus County. Programs such as outreach campaigns for preparedness education, continuing shelter inspections, and updating existing points of contact for shelter sites. These efforts will improve the American Red Cross’ ability to conduct mitigation, preparedness, and response efforts in Stanislaus County.

Dam Owners and Operators Coordination: Stanislaus County coordinates with numerous dam owners and operators, including owners upstream of the County. Coordination involves partnerships with federal, state, and local officials, agency engineers, emergency managers, emergency preparedness coordinators, dam owners and operators, and property owners near areas that can be potentially affected by dam incidents. Key agencies within the County’s partnership include the FEMA’s National Dam Safety Program (NDSP), Army Corps of Engineers (USACE), Bureau of Reclamation, California Division of Safety of Dams (DSOD), Pacific Gas and Electric (PG&E), Modesto Irrigation District (MID), Turlock Irrigation District (TID), Merced Irrigation District, Del Puerto Canyon Water District, and others such as South San Joaquin Irrigation District (SSJID), Modesto Irrigation District, the City of Modesto, and Oakdale Irrigation District (OID). Given there are range of mitigation actions that can be taken to reduce the risk of dam incidents and the effects of dam failure, the County has an ongoing partnership with key dam owners and operators in order to ensure each agency is aware of each other’s actions and to coordinate them effectively, 815
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recognizing that working together maximizes risk reduction. As a result, many of these dam owners and operators were invited as stakeholders to inform and support the update of the County’s MJHMP.

Information on these dam owners and operators are shown in the table below.

Table 2-12 Stanislaus County Dams of Concern Owner/Operator & Emergency Information County Dam Name Dam Owner/Operator
Whether or not an
office, department,
or agency supports
dam mitigation
actions
Stanislaus
Modesto
Reservoir MID Yes
Woodward SSJID Yes
Turlock Lake TID Yes
Modesto Effluent Storage City of Modesto Yes
Conagra Aerated and
Settling Ponds
ConAgra Grocery Products
Company, LLC Yes
Tuolumne
Don Pedro TID Yes
Don Pedro Dike A TID Yes
Don Pedro Dike B TID Yes
Don Pedro Dike C TID Yes
Relief PG&E Yes
Calaveras
Goodwin
Tri-Dam Project (Oakdale
Irrigation District & South San
Joaquin Irrigation District)
Yes
New Melones Bureau of Reclamation Yes
Tulloch SSJID Yes
Mariposa
Exchequer Dike Merced Irrigation District Yes
Exchequer Main
(New Exchequer) Merced Irrigation District Yes
Mcswain Merced Irrigation District Yes
Merced San Luis Reservoir Bureau of Reclamation,
California DWR Yes
Fresno Pine Flat USACE – Sacramento District Yes

2.16.6 Opportunities for Enhancement
The 2021 MJHMP update provided the County and the participating jurisdictions an opportunity to review and update the capabilities currently in place to mitigate hazards. This also provided an opportunity to identify where capabilities could be improved or enhanced. Specific opportunities could include:

Safety Plan Update: Stanislaus County has identified several plans which could be updated, specifically the County’s General Plan Safety Element last updated in 2016. During the MJHMP update process, the County also indicated they are in the process of soon updating the Safety Element. The County’s Safety Element was last updated in 2016 to incorporate by reference the 2010 LHMP, the County’s Planning and Community Development Department began scoping the Safety Element update as the MJHMP went out for public review. The County should incorporate the 2021-2022 MJHMP to become eligible again for CDAA funding in the event of a disaster; this process also ensures further consistency of each plan and provides an opportunity to reference the MJHMP and enhance the capabilities for implementation of goals and objectives of each plan. The Safety Element does not currently cover extreme heat, smoke, drought, and how these hazards disproportionately impact vulnerable and environmental justice communities. A comprehensive update of the Safety Element to include hazards and mitigation strategies addressed in the 2010-2022 MJHMP update will align and integrate each plan. 816
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Training: Provide training opportunities to help inform County staff on how best to integrate hazard information and mitigation projects into their departments. Stanislaus County has identified a multi-year training and exercise plan which would cover all county departments. There are also several financial resources that the County could leverage in the future for funding mitigation efforts. In particular, the MJHMP provides eligibility for the FEMA HMA grants. County OES staff can attend workshops and training regarding the grant application process and how to develop successful grant applications under the HMGP.

Cal OES periodically hosts related training and webinars. Understanding the types of projects that can be funded, and the components of a successful application will enhance the chances of a successful grant award.

Hazard Mitigation Specialist: The County could appoint or assign someone in OES to oversee hazard mitigation grant opportunities. This could be a follow-up goal to the Cal OES grant training. This specialist can notify the County departments/agencies of upcoming grant cycles, and support tracking and completing the Notice of Intent (NOI) applications, grant applications, and final grant management reporting requirements. Related financial opportunities for enhancement should include applying for HMA grants, such as BRIC and HMGP funding as it becomes available. The Hazard Mitigation Specialist should also focus on funding mitigation actions that mitigate critical infrastructure, provide protection for those most vulnerable in the community, address climate change, public health hazards, extreme heat, flooding, other climate-related hazards and needed and related climate adaptation strategies.

HMGP Technical Assistance: HMGP funding opportunity provides support for communities to implement mitigation activities to reduce risk to life and property from natural hazards. In California, natural hazards include wildfire, earthquake, drought, extreme weather, flooding, and other impacts of climate change. Cal OES technical subject-matter experts are available to discuss project eligibility, benefit cost analysis, technical feasibility, and Environmental and Historic Preservation (EHP) requirements.

Firewise: Firewise USA® is a voluntary program that provides a framework to help neighbors get organized, find direction, and take action to increase the ignition resistance of their homes and community.

The program is co-sponsored by the USDA Forest Service, the U.S. Department of the Interior, and the National Association of State Foresters. As of June 2021, neither Stanislaus County nor any of the incorporated jurisdictions in the County were participants in the program. In order to become a Firewise USA site, a neighborhood, community, city, or county must form a board or committee comprised of residents and stakeholders, obtain a written wildfire risk assessment, develop and maintain an action plan, and contact the applicable state liaison to the program.

Storm Ready: Neither Stanislaus County nor any of the incorporated jurisdictions in the County are certified as Storm Ready communities. Cal State Stanislaus is certified Storm Ready. The National Weather Service’s Storm Ready program helps local governments handle extreme weather and improve the timeliness and effectiveness of hazardous weather-related warnings for the public. To be officially Storm Ready, a community must:
• Establish a 24-hour warning point and EOC
• Have more than one way to receive severe weather warnings and forecasts and to alert the public • Create a system that monitors weather conditions locally • Promote the importance of public readiness through community seminars, and • Develop a formal hazardous weather plan, which includes training severe weather spotters and holding emergency exercises
Community Rating System (CRS): An additional indicator of floodplain management capability is the active participation of local jurisdictions in the CRS. The CRS is an incentive-based program that encourages counties and municipalities to undertake defined flood mitigation activities that go beyond the minimum requirements of the NFIP, adding extra local measures to provide protection from flooding. All 18 creditable CRS mitigation activities are assigned a range of point values. As points are accumulated and reach identified thresholds, communities can apply for an improved CRS class. Class ratings, which run from 10 to 1, are tied to flood insurance premium reductions. As class ratings improve (decrease), the percent reduction in flood insurance premiums for NFIP policy holders in that community increases. These potential discounts in flood insurance premiums through CRS are summarized in Table 2-12 below. 817
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As of 2021, City of Newman and City of Patterson currently participate in the CRS. Both cities have a Class 9 and received 5% discount. Neither Stanislaus County nor any of the other incorporated jurisdictions in the County participate in the CRS. Should the other jurisdictions and Stanislaus County decide to join the CRS, it would be an opportunity for enhancement of existing mitigation capabilities and help make flood insurance more affordable in the future.

Table 2-13 CRS Premium Discounts
Class Discoun
t
Class Discount SFHA (Zones A, AE, A1-A30, V, V1-V30, AO, and AH): Discount varies depending on class. SHFA (Zones A99, AR/A, AR/AE.

AR/A1-A30, AR/AH, and AR/AO): 10% discount for Classes 1-6; 5% discount for Classes 7-9. Non-SFHA (Zones B, C, X, D): 10% discount for Classes 1-6; 5% discount for Classes 7-9. In determining CRS premium discount, all AR and A99 Zones are treated as non-SFHAs.
1 45% 6 20%
2 40% 7 15%
3 35% 8 10%
4 30% 9 5%
5 25% 10 --
Source: FEMA CRS Coordinators Manual
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3 PLANNING PROCESS
Requirement §201.6(b) and §201.6(c)(1):

An open public involvement process is essential to the development of an effective plan. In order to develop a more comprehensive approach to reducing the effects of natural disasters, the planning process shall include:
(1) An opportunity for the public to comment on the plan during the drafting stage and prior to plan approval;
(2) An opportunity for neighboring communities, local and regional agencies involved in hazard mitigation activities, and agencies that have the authority to regulate development, as well as businesses, academia, and other private and non-profit interests to be involved in the planning process; and
(3) Review and incorporation, if appropriate, of existing plans, studies, reports, and technical information.
[The plan shall document] the planning process used to develop the plan, including how it was prepared, who was involved in the process, and how the public was involved.

3.1 Background on Mitigation Planning in Stanislaus County The primary purpose of the Stanislaus County MJHMP update is to reduce or eliminate long-term risk to people and property from natural hazards and their effects on the Stanislaus County planning area.

Stanislaus County recognized the need and importance of a MJHMP and initiated its development in 2017 after receiving a grant from FEMA, which also served as the primary funding source for this plan.

The plan underwent a comprehensive update in 2021-2022. The planning process followed during the update was similar to what was used in the original plan development, except that the 2021-2022 planning process involved participation from the nine municipalities in the County and the Stanislaus County Office of Education. The 2021-2022 planning process also involved a multi-jurisdictional HMPC. Wood Environment & Infrastructure Solutions, Inc. (Wood) was procured to assist with the update in 2021. The process is described further in this section and documented in Appendix B.

3.2 What’s New in the Plan Update
DMA Requirement §201.6(d)(3):

A local jurisdiction must review and revise its plan to reflect changes in development, progress in local
mitigation efforts, and changes in priorities, and
resubmit it for approval within 5 years in order to
continue to be eligible for mitigation project grant
funding.

The updated MJHMP complies with FEMA guidance and California OES guidelines for LHMPs. The update followed the requirements noted in the DMA of 2000 and FEMA’s 2013 Local Hazard Mitigation Planning Handbook.

This MJHMP update involved a comprehensive review and update of each section of the 2017 LHMP, the integration of a detailed risk assessment and consequence analysis, and an assessment of the progress in evaluating, monitoring, and implementing the mitigation strategy outlined in the initial plan. The planning process provided an opportunity to review jurisdictional priorities related to hazard significance and mitigation actions, and revisions were made where applicable to the base plan. Another change in priority was the desire to engage the nine incorporated jurisdictions in the County, including annexes for the municipalities of Ceres, Hughson, Modesto, Newman, Oakdale, Patterson, Riverbank, Turlock, and Waterford and the Stanislaus County Office of Education. While each jurisdiction participated in pervious MJHMP updates, representatives from multiple departments representing a Local Planning Team (LPT) 819
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were engaged and involved in the development of the 2022 MJHMP through multiple planning workshops and numerous one-on-one work sessions (See Section 1.8 for more information). Only the information and data still valid from the 2017 plan was carried forward as applicable into this MJHMP update. The 2017 LHMP Prerequisite section was integrated into the Executive Summary of the 2021-2022 MJHMP update.

Also, given the nine municipalities and the Office of Education participation, significant new hazard information was integrated into the base plan and into each annex. The 2017 LHMP assessed five priority hazards, including dam failure, earthquake, flooding, landslide, and wildfire. The 2021-2022 MJHMP update assessed 11 natural, human-caused, and human-health hazards, including agricultural pests and disease, aquatic invasive species (AIS), cyber threats, dam incidents, earthquake, extreme heat, flooding, landslides, public health hazards: epidemic/pandemic, Severe Weather: Dense Fog, Severe Weather:

Heavy Rain, Thunderstorms, Hail, and Lightning, Severe Weather: High Wind/Tornado, and wildfire. As a result, there are 14 new countywide mitigation actions, plus 75 jurisdiction-specific mitigation actions that were developed for the 10 annexes.

3.2.1 Plan Section Review and Analysis – 2021 Update
During the 2021-2022 MJHMP update, the HMPC updated each of the sections of the previously approved plan to include new information. Wood developed a summary of each section in the plan and guided the HMPC through the elements that needed updating during the kick-off webinar n May 2021. This included analyzing each section using FEMA’s Local Mitigation Planning Handbook (2013) and the Local Mitigation Planning Policy Guide (2022; Effective April 19, 2023) to ensure that the plan met the latest requirements.

In addition, the FEMA Local Mitigation Plan Review Tool that was provided with the approval of the 2017 version of this plan was referenced, in particular the 2017 FEMA comments on opportunities for improvement were considered and addressed in the 2021-2022 update. The HMPC and Wood determined that nearly every section of the plan would need revision to align the plan with the latest FEMA planning guidance and requirements and recent California legislation. A detailed summary of the changes in this plan update is highlighted in the table below.

Table 3-1 Stanislaus County Hazard Mitigation Plan Update Highlights Plan Section Summary of Plan Review, Analysis, and Updates

1. Introduction • Revised to reflect updated plan and 2021-2022 planning process

2. County Profile and
Capability Assessment
• Updated with recent census data and current economy description • Updated land use and development trends

3. Planning Process
• Describes and documents the planning process for the 2021-2022 update, including coordination among agencies
• Describes how 2017 plan was integrated with/into other planning efforts • Removed 2017 planning process information
• Describes changes to jurisdictional participation
• Describes 2021-2022 public participation process
• Summarizes the results of the Public Survey
• Describes the HMPC
• Describes the 10-step process followed for the update

4. Hazard Identification
and Risk Assessment
and Consequence
Analysis
• Climate change information has been added to each hazard profile • Updated list of disaster declarations to include recent data • Updated tables to include recent National Center for Environmental Information data • Updated past occurrences for each hazard to include recent data • 2017 Plan Vulnerability Assessment is now included with the Risk Assessment and an integrated Consequence Analysis section organized by hazard • The Consequence Analysis considers the impacts on the following assets: public; (2) responders; (3) continuity of operations including continued delivery of services; (4) property, facilities, and infrastructure; (5) environment; (6) economic condition of the jurisdiction; and (7) public confidence in the jurisdiction’s governance • Updated critical facilities identified from the 2017 plan; the critical facilities database now includes over 1,000 assets organized by Community Lifeline 820
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Plan Section Summary of Plan Review, Analysis, and Updates • Updated growth and development trends to include recent Census and local data sources from the County Community and Planning Department permit database • Updated historic and cultural resources using local/state/national sources • Updated property values for vulnerability and exposure analysis, using updated building information based on assessor’s data
• Updated estimate flood losses using the latest Digital Flood Insurance Rate Map (DFIRM) and assessor’s data
• Updated National Flood Insurance Program (NFIP) data and Repetitive Loss structure data from the previous plan
• Incorporated new hazard loss estimates since 2017, as applicable • Used updated GIS inventory data to assess wildfire threat to the County • Updated HAZUS-MH Level I earthquake vulnerability analysis data with two scenarios performed (one probabilistic scenario and one ShakeMap scenario) • Six additional hazards that were not included in the 2017 plan are added and profiled, which include: Agricultural Pests and Disease, AIS, Cyber Attack, Drought, Extreme Heat, Public Health Hazards: Pandemics/Epidemics, Severe Weather: Dense Fog, Severe Weather: Heavy Rain, Thunderstorms, Hail, and Lightning, Severe Weather:

High Wind/Tornado
• Updated information regarding specific vulnerabilities to hazards, including maps and tables of specific assets at risk, specific critical facilities at risk, and specific populations at risk
• Revisited and updated hazard significance/priority levels • Updated maps in plan where appropriate

5. Mitigation Strategy
• Indicated what actions have been implemented that may reduce previously identified vulnerabilities
• Updated mitigation strategy based on the results of the updated risk assessment, consequence analysis, completed mitigation actions, and implementation obstacles and opportunities since the completion of the 2017 plan • Reviewed and updated goals and objectives based on HMPC input • Added new objectives that are linked to the six new hazards profiled in the risk assessment and consequence analysis
• Included updated information on how actions are prioritized, or how priorities changed • Reviewed mitigation actions from the 2017 plan and developed a status report for each
• Identified if actions have been completed, deleted, or deferred/carried forward • Updated priorities on actions
• Combined similar mitigation actions from the 2017 plan related to CEQA review, floodplain management coordination, and avoiding development in hazard zones • Identify examples of successful implementation to highlight positive movement on actions identified in 2017 plan
• Identified new mitigation actions proposed by the HMPC with more detail on implementation than the previous plan
• 14 new countywide mitigation actions were added to address existing hazards and new hazards
• 75 new jurisdiction-specific mitigation actions were included in the annexes • Developed a summary table of mitigation actions for all participating jurisdictions

6. Plan Review,
Evaluation, and
Implementation
• Reviewed and updated procedures for monitoring, evaluating, and updating the plan • Revised to reflect current methods
• Updated the system for monitoring progress of mitigation activities by identifying additional criteria for plan monitoring and maintenance • Added a process for incorporation of the MJHMP update into existing mechanisms 821
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Plan Section Summary of Plan Review, Analysis, and Updates • Clarified future public involvement activities and tied them to the Outreach Strategy in Appendix F

7. Plan Adoption • Updated to reflect 2022 adoption process Jurisdictional Annexes
• *Developed annexes for new participating jurisdictions in 2021-2022 • Updated previous participants’ annexes with recent Census data • Updated past event history and hazard loss estimates
• Added new maps and updated old maps as needed
• Updated mitigation actions from 2017 and added new mitigation actions • Integrated the following annexes:

A City of Ceres
B City of Hughson
C City of Modesto
D City of Newman
E City of Oakdale
F City of Patterson
G City of Riverbank
H City of Turlock
I City of Waterford
J Office of Education
Appendices
• Appendix A: Planning Committee
• Appendix B: Planning Process Documentation
• Appendix C: Approval and Adoption
• Appendix D: Mitigation Categories and Alternatives
• Appendix E: Annual Progress Meeting Agenda and Report Template • Appendix F: Outreach Strategy

3.3 Multi-Jurisdictional Participation
In the 2021-2022 MJHMP update, the following jurisdictions participated in the planning process and will be adopting the updated plan following FEMA approval. All incorporated cities in the County participated in this planning process. As noted previously, all the incorporate cities in Stanislaus County are new to the multi-jurisdictional planning process.

Lead Jurisdiction:
• Stanislaus County
Municipalities:
• City of Ceres
• City of Hughson
• City of Modesto
• City of Newman
• City of Oakdale
• City of Patterson
• City of Riverbank
• City of Turlock
• City of Waterford
Other Jurisdictions
• Stanislaus County Office of Education
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The DMA planning regulations and guidance stress that each local government seeking FEMA approval of their mitigation plan must participate in the planning effort in the following ways:
• Participate in the process as part of the HMPC
• Detail areas within the planning area where the risk differs from that facing the entire area • Identify potential mitigation actions
• Formally adopt the plan
For the Stanislaus County planning area’s HMPC, “participation” meant the following:
• Providing facilities for meetings
• Attending and participating in the HMPC meetings
• Completing and returning Wood Plan Update Guide worksheets • Collecting and providing other requested data (as available) • Identifying mitigation actions for the plan
• Reviewing and providing comments on plan drafts and jurisdictional annexes • Informing the public, local officials, and other interested parties about the planning process and providing opportunity for them to comment on the plan
• Coordinating, and participating in the public input process • Coordinating the formal adoption of the plan by the governing boards The County and all jurisdictions with annexes to this plan and seeking FEMA approval met all these participation requirements. In most cases one or more representatives for each jurisdiction attended the multi-jurisdictional webinars/meetings described in Table 3-4 and brought together a local Planning Committee to help collect data, identify mitigation actions and implementation strategies, and review and provide data on annex drafts. In some cases, the jurisdictions had limited capacity to attend or had conflicts with HMPC meetings; in these cases, alternative forms of communication were used to provide input into the process, and some instances a representative from a different jurisdiction’s department attended the HMPC meeting on behalf of the main representative. County OES and Wood staff also meet via virtual meetings with individual jurisdictions, such as the cities of Hughson and Modesto to gather input on the planning process, existing capabilities, and new mitigation actions. Appendix B provides additional information and documentation of the planning process.

3.4 Planning Process
Wood established the planning process for the Stanislaus County MJHMP using the DMA planning requirements and FEMA’s associated guidance. The original FEMA planning guidance is structured around a four-phase process:
• Organize Resources
• Assess Risks
• Develop the Mitigation Plan
• Implement the Plan and Monitor Progress
Into this process, Wood integrated a more detailed 10-step planning process used for FEMA’s CRS and FMA programs. Thus, the modified 10-step process used for this plan meets the requirements of major grant programs including: FEMA’s HMGP, BRIC program, FMA Program, and flood control projects authorized by the U.S. Army Corps of Engineers.

In 2013, FEMA released the Local Mitigation Planning Handbook that has become the official guide for local governments to develop, update and implement local mitigation plans. While the requirements under §201.6 have not changed, the Handbook provides guidance to local governments on developing or updating hazard mitigation plans to meet the requirements under the CFR Title 44 – Emergency Management and Assistance §201.6, Local Mitigation Plans for FEMA approval and eligibility to apply for FEMA HMA grant programs. It also offers practical approaches, tools, worksheets, and local mitigation planning examples for how communities can engage in effective planning to reduce long-term risk from natural hazards and disasters. The Handbook complements and liberally references the Local Mitigation Plan Review Guide 823
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(October 1, 2011), which is the official guidance for federal and state officials responsible for reviewing local mitigation plans in a fair and consistent manner.

Table 3-2 shows how the modified 10-step process fits into FEMA’s four-phase process, and how these elements correspond to the tasks in the FEMA Mitigation Planning Handbook.

Table 3-2 Stanislaus County Hazard Mitigation Planning Process FEMA’s 4-Phase DMA Process Modified 10-Step CRS Process FEMA Local Mitigation Planning Handbook Tasks
1) Organize Resources
201.6(c)(1) 1) Organize the Planning Effort 1: Determine the planning area and resources
201.6(b)(1) 2) Involve the Public 2: Build the planning team - 44 CFR 201.6 (C)(1)
201.6(b)(2) and (3) 3) Coordinate with Other
Departments and Agencies
3: Create an outreach strategy - 44
CFR 201.6(b)(1)
4: Review community capabilities - 44
CFR 201.6 (b)(2)&(3)
2) Assess Risks
201.6(c)(2)(i) 4) Identify the Hazards 5: Conduct a risk assessment - 44 CFR 201.6 (C)(2)(i) 44 CFR
201.6(C)(2)(ii)&(iii) 201.6(c)(2)(ii) 5) Assess the Risks 3) Develop the Mitigation Plan
201.6(c)(3)(i) 6) Set Goals 6: Develop a mitigation strategy - 44 CFR 201.6(c)(3)(i); 44 CFR
201(c)(3)(ii) and 44 CFR
201.6(c)(3)(iii)
201.6(c)(3)(ii) 7) Review Possible Activities
201.6(c)(3)(iii) 8) Draft an Action Plan
4) Implement the Plan and Monitor Progress
201.6(c)(5) 9) Adopt the Plan 7: Review and adopt the plan 201.6(c)(4) 10) Implement, Evaluate, and
Revise the Plan
8: Keep the plan current
9: Create a safe and resilient
community - 44 CFR 201.6(c)(4)

3.4.1 Phase 1: Organize Resources
Planning Step 1: Organize the Planning Effort
The 2021-2022 planning process and update of the 2017 LHMP had its roots in the development of a grant application. The County OES wrote the grant and in the process solicited commitments from local government jurisdictions that were interested in participating. With an understanding of the number of jurisdictions and their commitment to participate, the grant application was approved and awarded to the County in 2020.

Wood worked with the County to get organized for the plan update. Organizational efforts were initiated with the County and participating jurisdictions in May 2021 to inform and educate the plan participants of the purpose and need for updating the countywide hazard mitigation plan. An initial meeting between Wood and County OES was held to discuss the organizational aspects of this plan update process. Invitations to the kick-off meeting for this plan update were extended to key County departments, the nine incorporated communities, County Office of Education, and representatives from special districts for the County and municipalities, as well as to other federal, state, and local stakeholders that might have an interest in participating in the planning process. Representatives from participating jurisdictions and HMPC members to the 2017 plan were used as a starting point for the invite list, with additional invitations extended as appropriate throughout the planning process. The County OES expanded an initial invite list that included participants in a pre-planning exercise held in 2020 that was focused on the identification and prioritization of natural and non-natural hazards with and without mitigation capabilities in place. The list of initial invitees is included in Appendix A.
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Representatives from the following County and municipal departments participated on the HMPC and the development of the plan update; these representatives are listed in Table 3-3. A list of specific HMPC representatives is included in Appendix A. Other local, state, federal, and private stakeholders invited to participate in the HMPC are discussed under Planning Step 3.

Table 3-3 List of HMPC Participants for 2021-2022 MJHMP Update Role Name Department
Emergency Services Manager Ruben Wegner Stanislaus County Office of Emergency Services
Purchasing/Facility Manager Javier Rocha Community Services Agency Deputy Chief Darin Jesberg City of Modesto, Fire Department, Community Risk Reduction
Community Services Agency Facility
Manager Mark Zachreus Community Services Agency
Fire Chief/City Emergency Manager Jeff Gregory City of Patterson, Fire Department Fire Chief* Michael Botto City of Turlock, Fire Department Assistant Chief* Kevin Wise City of Turlock & City of Ceres Fire Department
Fire Chief, City Emergency Manager Keith Bowen City of Newman, Fire Department City Manager Marisela Garcia City of Riverbank
Supervising Appraiser Ursula Spani Stanislaus County, Assessor’s Office City Emergency Manager Lonnie Statzer City of Waterford Senior Management Analyst Norma Manriquez City of Riverbank Division Chief Jeffery Fyre Patterson Fire Department
Senior Developer/Analyst Neil Mazuelos Stanislaus County, Assessor’s Office Stanislaus County Assessor Don Gaekle Stanislaus County, Assessor’s Office Staff Services Coordinator Robert Riess Stanislaus County, Health Services Agency, Emergency Preparedness
Deputy Director* Amanda Sharp Stanislaus County, Health and Human Services
Stanislaus County Fire Warden, Assistant
Director of OES Richard Murdock Stanislaus County Office of Emergency Services City Manager Bryan Whitemyer City of Oakdale
Community Services Agency/Public
Information Officer Dan Rosas Stanislaus County Community Services Agency Principal Planner Kristin Doud Stanislaus County, Planning & Community Development
Water Resource Engineering Miguel Alvarez City of Modesto, Utilities Department Facilities Analyst Sara Venicombe Stanislaus County Office of Education
Public Information Officer Judy Boring Stanislaus County Office of Education
Assistant Agricultural Commissioner Dan Bernaciak Stanislaus County Department of Agriculture
Hazardous Materials Manager Alvin Lal Stanislaus County Department of Environmental Resources
City Manager Merry Mayhew City of Hughson
Public Works Superintendent Jaime Velazquez City of Hughson City Manager* Tom Westbrook City of Ceres
Emergency Services Manager* Shannon Williams Stanislaus County Emergency Management Consultant
Source: HMPC 2022
*Indicates HMPC participants that changed or left positions during the HMPC planning process.

Planning Meetings
The planning process officially began with a kick-off meeting on May 26, 2021, which involved County OES staff and the Wood’s team. On August 5, 2021, the HMPC convened for the first time. The first HMPC meeting covered the scope of work and an introduction to the DMA requirements. Participants were 825
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provided with a Multi-Jurisdictional Local Hazard Mitigation Plan Update Workbook, which included worksheets to facilitate the collection of information necessary to support update of the plan. Using FEMA guidance, Wood designed these worksheets to capture information on past hazard events, identify hazards of concern to each of the participating jurisdictions, quantify values at risk to identified hazards, inventory existing capabilities, and record possible mitigation actions. A copy of Wood’s Multi-Jurisdictional Local Hazard Mitigation Plan Update Guide for this project is included in Appendix B. The County and each jurisdiction seeking FEMA approval of their plan completed and returned the worksheets in either the MultiJurisdictional Local Hazard Mitigation Plan Update Guide Workbook or shared their most recent local hazard mitigation plan for incorporation into the plan document.

During the planning process, the HMPC communicated through virtual meetings, email, and telephone conversations. With the exception of one in-person meeting with the County OES staff early in the planning process, all three HMPC meetings were held virtually due to social distancing requirements associated with the ongoing COVID-19 pandemic. Draft documents were emailed so that the HMPC members could easily access and review them. The County’s OES staff and HMPC formally met four times during the planning period (May 26, 2021 – January 13, 2022). The purposes of these meetings are described in Table 3-4.

The planning consultant sent meeting handouts ahead of time to the participating jurisdictions to review and provide feedback before or at the meeting. In addition to these meetings some jurisdictions held meetings with subcommittees to discuss the needed input for the plan update. In a couple cases some municipalities were not able to attend the planning workshops due to scheduling conflicts or limited staff capacity. The Emergency Services Coordinator of the County’s OES and the planning consultant worked with the jurisdictions individually in those cases to obtain necessary information and input into the planning process. This was done through direct emails from the planning consultant and follow-up phone conversations with the consultant and County OES where necessary.

Table 3-4 Summary of Planning Meetings
Meeting
Number
Meeting Topic Date Location
1 Kick-off/Planning Committee Roles and
Expectations (Stanislaus County OES staff only) May 26, 2021 Virtual/Webinar
– Microsoft
Teams
2 Overview of DMA 2000 & Hazard Mitigation
Planning Process / Review 2017 LHMP August 5, 2021 Virtual/Webinar – BlueJeans 3 Hazard identification and Risk Assessment November 9, 2021 Virtual/Webinar
– Microsoft
Teams
4 Mitigation Strategy and Goals Update / New
Mitigation Actions Brainstorm January 13, 2022
Virtual/Webinar
– Microsoft
Teams
Meeting #1 – Kick-off Meeting
On May 26, 2021, Stanislaus County’s OES staff and the Wood’s team convened and discussed the project background and the overall MJHMP update process, as well as the scope of work and project goals. County OES staff and Wood’s team also discussed the hazards that need to be profiled in this MJHMP update based on pre-planning exercises held in 2020 among the initial HMPC participants. In addition, County OES staff and Wood’s team reviewed potential additional HMPC members, partners, and stakeholders.

Moreover, the outreach plan needed for the MJHMP update and GIS data needs were also discussed during the kick-off meeting.

Meeting #2 – HMPC Meeting #1
On August 5, 2021, the HMPC convened virtually to discuss the process for completing the update of this plan. This first HMPC meeting was well attended with twenty-six (26) individuals present. The audience was a mix of county departments, local governments, special districts, and stakeholders. A complete list of those in attendance at the first HMPC meeting can be found in the sign-in sheets in Appendix B. 826
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Following introductions, Wood reviewed the DMA requirements and the suggested planning process to follow to meet the requirements as well as the expected schedule of the process. The roles of the HMPC and stakeholder were discussed including the participation requirements for the different roles.

During the first HMPC meeting, the HMPC validated the identified hazards within the 2017 plan, together with additional hazards that are added and profiled in this 2021-2022 MJHMP update. The HMPC collaboratively prioritized the hazards for the purpose of identifying which are “of most concern” to the County. More details are included in Section 4: Hazard Identification and Risk Assessment.

The group also discussed other agencies that should be part of this planning process, as well as related planning efforts to be coordinated with and recent studies to be incorporated. Part of this discussion was also related to creating a public outreach strategy to involve the public throughout the planning process.

This outreach strategy is included in Appendix F. The first HMPC meeting ended with Wood sharing handouts to assist in the planning process. These handouts included the Multi-Jurisdictional Local Hazard Mitigation Plan Update Workbook which outlined data collection needs for each participating jurisdiction.

Meeting #3 – HMPC Meeting #2: Risk Assessment and Mitigation Goal Refinement On November 9, 2021, the HMPC convened virtually to discuss the results of the risk and vulnerability assessment. Twenty (20) members of the HMPC were present for the discussion. Wood began the meeting with a presentation on the results the risk assessment and preliminary consequence findings for natural hazards and public health hazards. The group went through each hazard together and discussed the results as well as shared any local insight to inform the HIRA update. Refer to the meeting summary in Appendix B for notes related to each hazard discussed.

Following the discussion on the results of the risk assessment and consequence analysis findings, Wood explained this update process provides an opportunity to review the previous plan’s goals to determine if they are still valid, comprehensive, and reflect current priorities, updated risk assessment, and new consequence analysis. Inputs on mitigation goals and objectives were also solicited via virtual polls. The group was also encouraged to share insights on the development of mitigation goals, objectives, and specific actions and projects.

Wood shared with HMPC that the online public survey had been opened. A link was shared with the HMPC to easily distribute by email and for posting on each of the participating jurisdiction’s websites and MJHMP webpages. This was encouraged to promote engagement and input from the public and participating jurisdiction communities. The meeting ended with a review of the next steps and planning process schedule.

Meeting #4 – HMPC Meeting #3: Mitigation Strategy
The HMPC convened virtually on January 13, 2022, with 29 people participating to update the plan’s mitigation strategy. The group finalized the plan’s goals and objectives (Step 6) and reviewed the progress made on the previous mitigation actions from the 2017 LHMP. The group then discussed the criteria for mitigation action selection and prioritization using a worksheet provided by Wood. The group reviewed each possible new mitigation action. Additional details were provided by the Planning Committee (Step 7). This was followed by a brainstorming session to elicit the development of new mitigation actions. Wood then briefly explained the plan implementation and maintenance process. The meeting ended with a review of the next steps and planning process schedule. Wood provided the HMPC with a link to an online form to submit new mitigation actions. During the HMPC review of the full plan, each member was provided a handout on prioritizing new mitigation actions and asked to focus on prioritizing each new mitigation action for their jurisdiction.

Planning Step 2: Involve the Public
Involving the public assures support from the community at large and is a required part of the planning process per the DMA 2000. Early discussions with Stanislaus County and input received in the first HMPC meeting established the initial plan for public involvement in the plan update. Public outreach began with the development of an online public survey that was shared with each participating jurisdiction to post on their websites and disseminate via email to local stakeholders. The public outreach activities described here were conducted with participation from and on behalf of all jurisdictions participating in this plan. 827
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Throughout the planning process, two public workshops were held to inform the public of the purpose of the DMA and the hazard mitigation planning process for the Stanislaus County planning area. At each workshop, the public in attendance was provided links to electronic comment forms to leave any comments related to the County’s MJHMP as well as provide their contact information if they would like to receive ongoing updates and information related to the planning process.

At the first HMPC meeting, the HMPC discussed additional options for public involvement and agreed to an approach using established public information mechanisms and resources within the community. These additional options are outlined in the Community Outreach Strategy. Additional public involvement activities included press releases, website postings, flyer development and distribution, two public workshops, and the collection of public comments on the draft plan. Details on the outreach methods and approach are also summarized in the Community Outreach Strategy included in Appendix F.

Plan Facts
Plan Facts was created to increase public awareness of the hazard mitigation plan process by providing a simple two-page handout that could be used to inform the public and community leaders and other stakeholders about the importance of hazard mitigation planning and the plan update. Plan Facts is included on the County’s MJHMP webpage. The Wood team also provided the County with a Webpage Backgrounder document that included MJHMP update information for the MJHMP Webpage. Figure 3-1 includes a screenshot of the County’s MJHMP Webpage.
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Figure 3-1 Stanislaus County’s MJHMP Webpage and Information Resource Portal Source: Stanislaus County 2022
Online Public Survey
During the plan update’s initial drafting stage, an online public survey was used to gather public input to the Planning Committee. The survey provided an opportunity for public input during the planning process before the finalization of the plan update. The survey gathered public feedback on concerns about hazards and input on mitigation strategies to reduce their impacts. The survey was released on October 13, 2021 and closed on November 12, 2021 (one-month input period). The HMPC provided links to the public survey by distributing it using social media, email, and posting the link on websites. A link to the survey was also posted on some of the participating jurisdictions’ websites as well as through social media posts; screenshots from both can be found in Appendix B. A total of 77 people filled out the survey online. Results 829
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showed that the public perceives the most significant hazards to be drought, extreme temperatures, pandemic/epidemic, and climate change. Figure 3-2 shows the results of a question from the survey, which asked the public’s opinion on what mitigation actions should have the highest priority in the updated MJHMP. Water conservation, generators for critical facilities, public education/awareness, stormwater drainage improvements and improve reliability of communication systems were cited as the most popular mitigation actions. This information was shared with the HMPC during the update of the mitigation strategy to consider when evaluating hazard rankings and as a source of potential mitigation ideas. A summary of all the survey data and documentation of the public feedback can be found in Appendix B.

Figure 3-2 Results from Question 4: The following types of mitigation actions may be considered in Stanislaus County. Please indicate the types of mitigation actions that you think should have the highest priority in the Stanislaus County MJHMP.

Source: Wood 2022
Online Public Workshops
Two online public workshops were held during the planning process to inform the public, receive input to integrate into the plan update, and keep the public updated on the progress being made in the planning process. Both workshops were held virtually as webinars followed by question and answer sessions (Q&A) due to social distancing requirements associated with the ongoing COVID-19 pandemic. 830
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The first workshop took place on November 4, 2021 through Microsoft Teams. The workshop introduced the public to the hazard mitigation planning process for the County’s Plan Update and answered any questions and gather public input to be integrated into the plan update. In addition, it was an opportunity to help staff identify risks, hazards, and vulnerabilities from the public’s perspective. Fifteen individuals not including County staff participated in the first workshop. Members of the public were able to submit comments and ask questions verbally or via the chat function. Meeting participants such as the Environmental Justice Program of Catholic Charities of Stockton expressed their willingness to be involved in the MJHMP’s development. Stakeholder participants from the Mid San Joaquin River Flood Management Plan inquired about how their working group can integrate flood management projects into the County MJHMP. The HMPC also received various questions and comments from the workshop on the public’s priority hazards in their community and possible mitigation ideas to reduce hazard risk. From this input the County updated information in the risk assessment on flood hazard risk with specific information from the Mid San Joaquin River Flood Management working group. The County also inquired about potential mitigation action ideas from the Environmental Justice Program of Catholic Charities of Stockton, integrated these mitigation ideas into the mitigation strategy, and included the organization as a key mitigation partner.

Figure 3-3 is a snapshot from the first workshop.

Figure 3-3 First Public Workshop for the Stanislaus County MJHMP The second public workshop took place on June 23, 2022 while the draft plan was out for public review.

The workshop was noticed with a press release and social media postings. The workshop was online using MS Teams and was simultaneously broadcasted as a Facebook Live event by the County. The second virtual public workshop was an opportunity to learn more about the updated draft MJHMP including the planning process, the hazards assessed, and the mitigation actions proposed in the MJHMP. The second virtual public workshop was also an opportunity to explain how the community can review and comment on the MJHMP update. Following the public workshop was an opportunity for the public to comment on the draft MJHMP during the meeting. Seven persons attended the Teams session. There were no comments received during the workshop. The recording of the meeting was subsequently posted on the County’s Facebook Webpage. The County encouraged participation and feedback by attending the public workshop, visiting the County’s Project Webpage, and/or commenting on the Public Review Draft MJHMP. Figure 3-4 is a snapshot from the second workshop.
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Figure 3-4 Second Public Workshop for the Stanislaus County MJHMP Geographic Information System (GIS) Data Collection
When the Risk Assessment for the LHMP was originally prepared in 2017, the County’s OES was responsible for all the GIS mapping. The Project Manager, who previously served as the County’s former Chief Information Officer in the previous LHMP in 2011, scheduled a GIS internal meeting on April 6, 2016, to discuss the update process and schedule, plan review, data gathering, and GIS hazard mapping for the Plan update. A similar process occurred for the 2021-2022 MJHMP update. The GIS Manager compiled and provided the Wood team with access to the County’s GIS data.

During the kick-off meeting, which the County’s OES staff and Wood participated in, the MJHMP update process and schedule, plan review, data gathering, and GIS hazard mapping for the Plan update were discussed. In attendance were representatives from the County’s Information Technology Central (ITC), Public Works, and the Assessor’s Office. The County’s GIS Manager reviewed a GIS Data Needs List provided by Wood. The GIS team proceeded to discuss the details of the GIS mapping requirements, such as including inventory and valuation information for public infrastructure for each of the five identified hazards: earthquake, landslide, dam failure, flood, and wildfire. The team also discussed GIS data sources for the potential new hazards. Other related comprehensive inventory information that was discussed included: roads, traffic signals, drainage facilities, lighting facilities, bridges, and airports.

Most of the inventory and risk data can be layered to provide aggregation of asset values within specifically identified risk areas. Additional hazard-specific data and layers were acquired, layered, and analyzed to quantify the geographic extent as well as the magnitude and severity of hazards for each of the five identified hazards in the 2017 LHMP: earthquake, landslide, dam failure, flood, and wildfire. Data sources include USACE, DWR, HIFLD, NID, FEMA, CALFIRE, FRAP, DOC and California Geological Survey.

Additional GIS spatial data was integrated to assess agricultural pests and disease (important farmland) and severe weather.

During the HIRA process, to assess hazards’ potential impacts on the County’s critical facilities, a critical facilities GIS database was needed and then established. While building the critical facilities GIS database, each participating jurisdiction’s assistance was requested to validate the critical facilities GIS data. There were two primary aspects of this: data completeness/correctness and alignment/classification with FEMA Lifelines framework. The County and ten participating jurisdictions each reviewed the critical facility database and were encouraged to edit descriptive attributes and add new point data for critical facilities.

Specifically, the following jurisdictions, agencies and County departments’ staff provided inputs on the database: Keith Bowen from the City of Newman provided input on critical facilities within the City of 832
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Newman. Alvin Lal from the County’s Department of Environmental Resources provided inputs regarding critical facilities that carry extremely hazardous substances within the County. Merry Mayhew from the City of Hughson provided input on critical facilities within the City of Hughson. Judy Boring from the Office of Education provided inputs on facilities that are related to the Office of Education, such as schools. This process further engaged participating jurisdictions that saw the value of the MJHMP and long-term use and maintenance of the critical facility data moving forward. The result was an updated comprehensive critical facilities database with over 1,000 facilities.

Risk Assessment and GIS Methodology
• Identify Structures—buildings, infrastructure, critical facilities, structures that house elderly or disabled and transportation systems—both for present assets and those planned—categorized by FEMA Lifelines.
• Address Repetitive Loss Properties for flood hazard.
• Estimate Potential Property Losses. The development of the MJHMP includes an inventory of assets from each publicly governed jurisdiction, coordinated by Stanislaus County, and an assessment of hazard risks: AIS, agricultural pest and disease, cyber threats, dam incidents, earthquakes, extreme heat, flooding, landslides, severe weather and wildfires. • The asset inventory provided by the County Assessor’s Office database includes individual parcels, various lands use codes, and various taxing agencies or districts. • County property (building asset) inventory and valuation—for both present assets and those planned (within jurisdictions’ Sphere of Influence [SOI]).
• Each property within this County property inventory has its Assessor’s Parcel Number (APN), assessor's use code, government jurisdiction, and valuation data. Property value includes both improved value and estimated content value.
• County property type includes commercial, residential, agricultural, industrial, and vacant. • From Census data, the number of people that would be affected by each natural hazard is calculated, which is the product of the number of properties that would be affected and average household size. • During an update to the risk assessment, local jurisdictions must consider current and expected future vulnerability to all hazards and integrate new hazard data such as flood studies. Local jurisdictions were asked to incorporate replacement costs for vulnerable buildings and impacts of population growth or loss in vulnerable areas. Wood staff integrated this information, if available from each jurisdiction after the critical facilities assessment was complete. This process helped the jurisdictions understand what facilities were vulnerable to hazards and gather replacement value for these facilities. • The Consequence Analysis is a qualitative summary that addresses the impacts on the public; responders; continuity of operations including continued delivery of services; property, facilities, and infrastructure; environment; economic condition of the jurisdiction; and public confidence in the jurisdiction’s governance.

Strategic Business Technology (SBT)—Geographical Information System (GIS) The County’s GIS system used for the MJHMP update and is based on ESRI’s ArcGIS Desktop software and is capable of performing sophisticated GIS layer creation, analysis, and mapping tasks. ESRI’s software is the County GIS standard, used by most, if not all other County departments actively involved in GIS—including SBT, the EOC, and 9-1-1.

Public Review Period
The County OES department circulated the Public Review Draft MJHMP for a 30-day period from June 20, 2022 through July 22, 2022. The Public Review Draft was released for comment and made available for download via the County OES website. The Public Review Draft MJHMP was advertised through social media, mass emailing, and an advertisement through the media mechanisms noted previously. An electronic comment form through Microsoft Forms was provided with the draft plan. One comment was received on the Public Review Draft MJHMP. The comment received was shared with the HMPC and incorporated into the plan. The comment and response are briefly summarized in Table 3-5. 833
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Table 3-5 Summary of Comments Received during Public Review Comment Response
Electronic Written Comment #1
• There was a written comment on Table 4-16, noting
that the storage noted for Don Pedro dam is incorrect,
while the correct number is 2,030,000 acre-feet.
• Comment noted. Table 4-16 is updated. The County
appreciates the time and effort to provide feedback on
the Draft MJHMP.

3.4.2 Planning Step 3: Coordinate with Other Departments and Agencies Early in the planning process, state and local agencies and organizations were invited to participate as stakeholders in the process through email. Stakeholders include local and regional agencies involved in hazard mitigation activities or those beyond the County and local government that have the authority to regulate development. The Stanislaus County Cooperator’s List provided the basis for a contact list, which was maintained by County OES and updated by both the County and the planning consultant. Some of the cooperators invited to review the Administrative Draft MJHMP included surrounding counties, such as Merced, San Joaquin, and Tuolumne counties. Stakeholders could participate in various ways, either by contributing input at HMPC meetings, being aware of planning activities through an email group, providing information to support the effort, or reviewing and commenting on the draft plan. Based on their involvement in other hazard mitigation planning efforts, and status in the County, representatives from the following agencies and organizations were invited to participate as stakeholders in the process by email; an asterisk indicates they participated in HMPC meetings. More specific on stakeholder agency representatives can be found in Appendix A and documentation in Appendix B.

Neighboring Counties
• County of Alameda
• County of Calaveras
• County of Merced
• County of Santa Clara
• County of San Joaquin
• County of Tuolumne
Federal, State, and Local Agencies
• USACE
• California OES
• California Department of Fire Protection and Forestry • California Natural Resource Agency
• California DSOD
• California DWR
• California Department of Parks and Recreation
• FEMA Region IX
• San Joaquin River National Wildlife Refuge
• National Oceanic Atmospheric Administration/National Weather Service • County Agricultural Commissioner*
• Stanislaus Council of Governments
• SCFPD*
Businesses, Academia, Utility Providers, Dam Owners and Operators and Non-Profits • American Red Cross
• California State University, Stanislaus
• PG&E
• Central Valley Specialty Hospital
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• Oakdale Irrigation District
• Turlock Irrigation District
• Merced Irrigation District
• Modesto Irrigation District
• South San Joaquin Irrigation District
• West Stanislaus Irrigation District
• Environmental Justice Program of Catholic Charities of Stockton • Mid San Joaquin River Regional Flood Management Planning Group (one of six DWR flood management regional planning groups in the Central Valley) Incorporation or Existing Plans and Other Information
The coordination and synchronization with other community planning mechanisms and efforts are vital to the success of this plan. To have a thorough evaluation of hazard mitigation practices already in place, appropriate planning procedures should also involve identifying and reviewing existing plans, policies, regulations, codes, tools, and other actions are designed to reduce a community’s risk and vulnerability from natural hazards. Stanislaus County uses a variety of mechanisms to guide growth and development.

Integrating existing planning efforts, mitigation policies, and action strategies into this plan establishes a credible, comprehensive document that weaves the common threads of a community’s values together.

The development and update of this plan involved a comprehensive review of existing plans, studies, reports, and initiatives from Stanislaus County and each participating municipality that relate to hazards or hazard mitigation. A high-level summary of the key plans, studies and reports is summarized in the table below. Information on how they informed the update is noted and incorporated where applicable.

Table 3-6 Summary of Review of Key Plans, Studies and Reports Plan, Study, Report Name How Plan Informed LHMP
Stanislaus County General Plan The Stanislaus County General Plan was adopted by the Board of Supervisors on August 23, 2016. The
County proactively addresses hazards through the
General Plan Safety Element and has many references
to the MJHMP, which is synonymous with the LHMP.

Representatives from the work group for the General
Plan are also members of the MJHMP HMPC, ensuring
that both plans are integrated and contain mutuallyreinforcing policies. The General Plan and the 2021 MJHMP Update work together to achieve the goal of
hazard risk reduction. Future updates of the General
Plan, including incorporation by reference of the 2021- 2022 MJHMP into the Safety Element will continue to
ensure consistency between both plans.

The General Plan also includes the Housing Element
chapter. The Housing Element is incorporated into the
MJHMP to identify development trends.

Stanislaus County Capital Improvement Plan The Stanislaus County Capital Improvement Plan, along with the Capital Project Program, supports the
goal of the County to protect critical facilities and
infrastructure. The Capital Projects Team is actively
working to incorporate MJHMP priorities in the CIP
development to protect facilities and infrastructure
important to the County Areas of repetitive loss are high priorities for mitigation funding as they can negatively affect County coffers.

Stanislaus County Emergency Operations Plan The Stanislaus County 2021 EOP establishes an emergency management organization and assigns
functions and tasks consistent with California’s SEMS
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Plan, Study, Report Name How Plan Informed LHMP
and the NIMS. It provides for the integration and
coordination of planning efforts of multiple jurisdictions.

This plan was developed utilizing the “whole
community” planning process as outlined in FEMA’s
Comprehensive Preparedness Guide 101 and was
reviewed and approved by representatives from each
Stanislaus County department as well as members of
the Operational Area Council and County/City Disaster
Council. The content is based on guidance approved
and provided by the State of California and FEMA. The
EOP provides direction on how to respond to an
emergency from the initial onset, through an extended
response, and into the recovery process.

A key element of the update process for this hazard
mitigation plan was the annual review of the EOP. The
HMPC remained informed of major review findings of
the EOP with the intent to integrate with key
components of the hazard mitigation plan. Future
updates to the EOP will coincide with the future updates of the MJHMP.

Stanislaus County Code, Title 16 Buildings and
Construction
The Stanislaus County Code, Title 16 provides
minimum standards to safeguard life, health, property,
and the public welfare by regulating and controlling the design, construction, quality of materials, use and
occupancy, location, and maintenance of all buildings
and structures within the unincorporated areas of the
County.

Stanislaus County Code, Chapter 16.50, Floodplain
Management
The purpose of this Chapter is to promote the public
health, safety, and general welfare, and to minimize
public and private losses due to flood conditions in
specific areas through specific provisions.

This ordinance was used as a reference to assess
County’s mitigation capabilities and design mitigation
actions and projects.

Stanislaus County Code, Chapter 16.55, Fire Code Addresses requirements, responsibilities, and provisions for the prevention of fires and the spreading of fires as it pertains to structures. This ordinance was used as a reference to assess County’s mitigation
capabilities and design mitigation actions and projects.

Stanislaus County 2017 LHMP The plan was reviewed to provide a basis for the current update.

Assessor for parcel data including Use Codes;
assessed categories; and values
Used for quantitative vulnerability assessment for
hazards. Parcel information was integrated into each
hazard “Property” section in the vulnerability
assessment.

Public Works for current infrastructure list (Bridges,
Drainage, Street Lights, and Traffic Lights) and their
geographic placement
Used to establish critical facilities GIS database.

GIS for numerous base map shape files such as cities,
county, parcels, rivers, and roads
Used to establish critical facilities GIS database.

Modesto Subbasin Groundwater Sustainability Plan
(January 2022)
Provided policy context for drought hazard; used as a
reference to design mitigation actions and projects.

East Stanislaus Integrated Regional Water
Management Plan (IRWM) (2018)
Provided policy context for drought hazard; used as a
reference to design mitigation actions and projects.
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Plan, Study, Report Name How Plan Informed LHMP
Mid San Joaquin River Regional Flood Management
Plan (MSJR RFMP) (2017)
Provided policy context for flood hazard; used as a
reference to design mitigation actions and projects.

Central Valley Flood Protection Plan (2022 Update) Provided policy context for flood hazard; used as a reference to design mitigation actions and projects.

FEMA Flood Insurance Rate Map 100- and 500-year floodplain data was acquired to profile flood hazard and carry out the related
vulnerability assessment.

USACE Comprehensive Study; DWR Awareness
Floodplain Mapping project
USACE 100-year flood event layer and DWR Best
available maps in 200-year flood event layer were
acquired to profile flood hazard and carry out the
related vulnerability assessment.

FEMA Technical Bulletin 11-01 Crawlspace
Construction for Buildings located in Special Flood
Hazard Areas NFIP Interim Guidance
Provides guidance on crawlspace construction; used as
a reference to design mitigation actions and projects.

NFIP This program aims to reduce the impact of flooding on private and public structures by providing affordable
insurance to property owners and by encouraging
communities to adopt and enforce floodplain
management regulations. These efforts help mitigate
the effects of flooding on new and improved structures.

NFIP data was incorporated into the vulnerability
assessment for flood hazard.

NIMS This system directs the creation of a comprehensive, national approach to incident management by federal,
state, territorial, Tribal, and local responders and across all functional disciplines.

Federal Energy Regulatory Commission (FERC) FERC is an independent agency that regulates interstate transmission of electricity, natural gas, and oil. FERC also reviews proposals to build liquefied
national gas (LNG) terminals and interstate natural gas pipelines as well as licensing hydropower projects and
providing regulations of dams.

California Geological Survey, USGS Data was acquired to profile and carry out vulnerability assessment for earthquake and landslide hazard.

California Code of Regulations, Title 24, Part 9
(California Building Standards Code) (Fire Code)
CCR Title 24 governs the design and construction of all building occupancies and associated facilities and
equipment throughout California and is also known as
building standards. It contains requirements for the
structural, mechanical, electrical, and plumbing
systems, and requires measures for energy
conservation, green design, construction and
maintenance, fire and life safety, and accessibility.

The code is used as a reference to design mitigation
actions and projects.

Alquist-Priolo Earthquake Fault Zoning Act The Alquist-Priolo Earthquake Fault Zoning Act’s main purpose is to prevent the construction of buildings used for human occupancy on the surface trace of active
faults.

Relevant data was acquired to profile earthquake
hazard.

CEQA CEQA is a California statute passed in 1970 (shortly after the United States Federal Government passed the
National Environmental Policy Act 9NEPA), to institute
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Plan, Study, Report Name How Plan Informed LHMP
statewide policy of environmental protection. The
County will complete supporting CEQA documentation
prior to board approval and adoption.

California Public Resources Code (PRC) Section 4291
– Structures in Fire Hazard Areas
This code provides direction for persons owning,
leasing, controlling, operating, or maintaining any
building or structure in, upon, or adjoining any
mountainous area of forest-covered lands, brushcovered lands, or grass-covered lands, or any lands which is covered with flammable material.

The code is used as a reference to design mitigation
actions and projects.

Municipal General Plans (including Safety Elements,
Land Use Elements, and Housing Elements)
Informed the municipal annexes and in some cases the
community service district annexes on past hazard
events, mitigation policies, combining designations and existing and projected development.

Stanislaus County Flood Insurance Study Reviewed for information on past floods and flood problems to inform risk assessment and consequence
analysis (Section 4).

Utilized Digital Flood Insurance Rate Maps effective
2018 State of California Multi-Hazard Mitigation Plan Reviewed information on climate change and hazard assessment data to ensure consistency with this plan
update.

Reviewed list of hazards to inform risk assessment and
consequence analysis (Section 4).

Reviewed goals for consistency
California Department of Forestry and Fire Protection
(CALFIRE) and the Fire and Resource Assessment
Program (FRAP)
Data was acquired to profile and carry out vulnerability assessment for wildfire hazard.

NOAA National Centers for Environmental InformationState Climate SummariesReviewed information on climate change to inform risk assessment and consequence analysis.

California DOF/U.S. Census Bureau, ACS, 2015-2019 Informed the background on the community including demographic trends and the calculation of population at risk.

USDA Risk Management Agency Crop Indemnity
Reports, 2007-2020
Informed the adverse weather section vulnerability
assessment on how crops have been impacted by
weather events in the past. Also informed the Drought,
Severe Weather and Agricultural Pests and Disease
sections of the HIRA.

California Climate Adaptation Strategy, 2018 and
California OES Contingency Plan for Excessive Heat
Emergencies (2014)
Informed the Extreme Heat profile and climate change
considerations in the risk assessment and
consequence analysis.

All relevant plans, codes, and ordinances currently in
place such as building codes, zoning ordinances,
subdivision ordinances, special purpose ordinances,
site plan review requirements, growth management
ordinances, economic development plans, and
emergency response plans were reviewed
Reviewed and used to profile and carry out vulnerability assessment for hazards.

Used as references to design mitigation actions and
projects.

In the process of preparing this hazard mitigation plan, many other existing plans, studies, reports, and technical information were evaluated or used as guidance. The HMPC for the development of the MJHMP Update included representatives who are charged with developing the Stanislaus County General Plan, the Stanislaus County CIP, and the Stanislaus County EOP. The Planning Committee members work to ensure 838
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that local plans are integrated with the MJHMP and provide expertise for the integration of other local, state, and federal plans, codes, and regulations.

Other technical data, reports and studies were reviewed and considered, as appropriate, during the collection of data to support Planning Steps 4 and 5, which include the hazard identification, vulnerability assessment, and capability assessment. Information from the following agencies and groups were reviewed in the development and update of this plan. Specific references relied on in the development of this plan are also sourced throughout the document as appropriate. • California Department of Forestry and Fire Protection • California Department of Parks and Recreation Office of Historic Preservation • California Department of Transportation
• California Department of Public Health
• California Natural Resources Agency
• California DSOD
• California DWR
• California Geological Survey
• Stanislaus County Agricultural Department
• Stanislaus OES
• California Water Foundation
• FEMA
• National Oceanic and Atmospheric Administration National Climatic Data Center • National Register of Historic Places
• Natural Resource Conservation Service
• National Weather Service
• U.S. Fish and Wildlife Service
• U.S. Geological Survey
• Western Regional Climate Center
• Center for Western Weather and Water Extremes
Integration of 2017 Plan into Other Plans and Planning Mechanisms While the 2017 LHMP was not specifically incorporated or referenced in county or municipal plans and planning mechanisms, a process to do so with the 2021-2026 plan is outlined in Subsection 6.3.3. For example, the County amended the General Plan Safety Element to incorporate the 2010 LHMP; however, the 2017 LHMP was not incorporated into the Safety Element. There is a process noted in both Subsection

6.3.3 and corresponding mitigation actions in Subsection 5.3 that outline how the County and municipalities can achieve Assembly Bill (AB) 2140 compliance, which recommends adoption by reference or incorporation of the MJHMP into the Safety Element of the General Plan. The County was actively coordinating an amendment of the General Plan Safety Element to accommodate this during the finalization of this MJHMP in 2022. The County Planning and Community Development Department also intends to use that process to address compliance with Assembly Bill (AB) 747 and Senate Bill 99 related to evacuation route capacity and the identification of residential neighborhoods that do not have at least two ingress/egress routes.

3.4.3 Phase 2: Assess Risks
Planning Step 4: Identify the Hazards
Wood led the HMPC in an effort to review the list of hazards identified in the 2017 plan and document all the hazards that have, or could, impact the planning area, including documenting recent drought, flood, wildfire and severe storm events that were not included in the 2017 LHMP. Data collection worksheets were used in this effort to aid in determining hazards and vulnerabilities and where risk varies across the planning area. The profile of each of these hazards was then updated in 2021 with information from the HMPC and additional sources. Web resources, existing reports and plans, and existing GIS layers were used to compile information about past hazard events and determine the location, previous occurrences, probability of future occurrences, and magnitude/severity of each hazard. GIS was used to display, analyze, and 839
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quantify hazards and vulnerabilities where data permitted. The potential for climate change to affect the frequency and intensity of the hazards was summarized based on latest available science, where applicable. A more detailed description of the HIRA process and the results are included in Section 4:

Hazard Identification and Risk Assessment.

Planning Step 5: Assess the Risks
After updating the profiles of the hazards that could affect the County, the HMPC collected information to describe the likely impacts of future hazard events on the participating jurisdictions. This step included two parts: a vulnerability assessment and a capability assessment.

Vulnerability Assessment – Participating jurisdictions updated their assets at risk to natural hazards— overall and in identified hazard areas. These assets included total number and value of structures; critical facilities and infrastructure; natural, historic, and cultural assets; and economic assets. The HMPC also analyzed development trends in hazard areas. Population at risk was also assessed and calculated for dam incidents, earthquake, flood, landslide, and wildfire hazards. The latest DFIRM was used to refine the estimate flood losses during the update, where available for the NFIP participating communities.

Consequence Analysis – New to the MJHMP is a Consequence Analysis to align the plan update with the Emergency Management Accreditation Program (EMAP) standards. The EMAP is a voluntary standards, assessment, and accreditation process for disaster preparedness programs throughout the country. It provides emergency management programs the opportunity to be recognized for compliance with industry standards, to demonstrate accountability, and to focus attention on areas and issues where resources are needed. The EMAP program consists of 66 standards, last updated in 2019 that evaluate all aspects of a jurisdiction’s comprehensive emergency management program.

Two EMAP standards specifically address hazard assessment and mitigation planning:
• Standard: 4.1 Hazard Identification, Risk Assessment and Consequence Analysis • Standard: 4.2 Hazard Mitigation
EMAP Standard 4.1 identifies the natural and human-caused hazards that potentially impact a jurisdiction using multiple sources and assesses the risk and vulnerability of people, property, the environment, and its own operations from these hazards. The Consequence Analysis also considers the hazard impacts on the public; responders; continuity of operations including continued delivery of services; property, facilities, and infrastructure; environment; economic condition of the jurisdiction; and public confidence in the jurisdiction’s governance. Refer to Subsection 3.4.6 for a crosswalk that describes how the 2021-2016 Stanislaus County Multi-Jurisdictional Hazard Mitigation Plan is prepared in compliance with the EMAP standards.

Capability Assessment – The HMPC conducted a capability assessment update to review and document the planning area’s current capabilities to mitigate risk and vulnerability from hazards. By collecting information about existing government programs, policies, regulations, ordinances, and emergency plans, the HMPC can assess those activities and measures already in place that contribute to mitigating some of the risks and vulnerabilities identified. This information for the County is included in Section 6 and in the respective jurisdictional annexes. This addressed FEMA planning task 4: Review community capabilities - 44 CFR 201.6 (b)(2) & (3).

Results of the risk assessment was presented, and comments discussed at the second HMPC meeting in November 2021. A more detailed description of the risk assessment and consequence analysis process and the results are included in Section 4: Hazard Identification and Risk Assessment.

3.4.4 Phase 3: Develop the Mitigation Plan
Planning Step 6: Set Goals
Wood facilitated a discussion session with the HMPC to review the 2017 LHMP’s goals and objectives. The HMPC discussed definitions and examples of goals, objectives, and actions and considered the goals of in the SHMP and other relevant local plans when reviewing and revising the goals and objectives. The resulting updated goals and objectives are presented in Section 5: Mitigation Strategy. For the 2021-2022 MJHMP, goals were modified and several objectives specific to each hazard were added. 840
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Planning Step 7: Review Possible Activities
Wood facilitated a discussion at an HMPC meeting to review the alternatives for mitigating hazards. This included a brainstorming session with the HMPC to identify a comprehensive range of mitigation actions for each identified hazard, and a method of selecting and defending recommended mitigation actions using a series of selection criteria. More specifics on the process and the results of this collaborative process are captured in Section 5: Mitigation Strategy.

As part of the review of mitigation options long-term climate change adaptation strategies were also discussed. HMPC members were encouraged to incorporate climate change adaptation measures into the mitigation strategy of their respective jurisdictions utilizing resources and guidance available on the CalAdapt website and the California Adaptation Planning Guide.

Planning Step 8: Draft an Action Plan
Based on input from the HMPC regarding the draft risk assessment and the goals and activities identified in Planning Steps 6 and 7, Wood produced a complete first draft of the plan. This complete Administrative Draft MJHMP was shared electronically with the HMPC for review and comment. Other agencies were invited to comment on this draft as well, specifically surrounding counties. HMPC and agency comments were integrated into the second draft, which was advertised and distributed to collect public input and comments. Neighboring county emergency managers and interested stakeholders identified under Step 3 were also solicited to provide comments on the draft plan during the public review period; no comments were received. Wood integrated comments and issues from the public, as appropriate, along with additional internal review comments and produced a final draft for the California OES and FEMA Region IX to review and approve, contingent upon final adoption by the governing boards of each participating jurisdiction.

3.4.5 Phase 4: Implement the Plan and Monitor Progress
Planning Step 9: Adopt the Plan
In order to secure buy-in and officially implement the plan, the plan was adopted by the governing boards of each participating jurisdiction on the dates included in the adoption resolutions in Appendix C. The final plan will be incorporated by reference in the Safety Element of the County General Plan and result in the County’s eligibility for Assembly Bill (AB) 2140. This adoption makes the jurisdiction eligible for consideration for part or all its local costs on eligible public assistance to be provided by State share funding through the CDDA.

Planning Step 10: Implement, Evaluate, and Revise the Plan The true worth of any mitigation plan is in the effectiveness of its implementation. Up to this point in the plan update process, all the HMPC’s efforts have been directed at researching data, coordinating input from participating entities, and updating and developing appropriate mitigation actions. Each recommended action includes key descriptors, such as hazard(s) addressed, lead manager and priority, to help initiate implementation. An overall implementation strategy is described in Section 6: Plan Adoption, Implementation, and Maintenance.

Finally, there are numerous organizations within the Stanislaus County planning area whose goals and interests’ interface with hazard mitigation. Coordination with these other planning efforts, as addressed in Planning Step 3, is paramount to the ongoing success of this plan and of mitigation in Stanislaus County and is addressed further in Section 6. A plan update and maintenance schedule and a strategy for continued public involvement are also included in Section 6.

Implementation and Maintenance Process: 2017 LHMP
The 2017 LHMP included a process for implementation and maintenance which was generally followed, with some variation. Implementation of the plan including the status of mitigation actions is captured in Section 5 and the jurisdictional annexes. In general, the County and participating jurisdictions have made progress in the implementation of the plan. Successes of note are detailed in the mitigation strategy in Section 5. An updated implementation and maintenance section can be referenced in Section 6. 841
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3.4.6 EMAP Standards Crosswalk
This crosswalk demonstrates compliance with the EMAP standards described in Subsection 3.4.3 – Phase 2: Assess Risks. The associated subsections and references where the information that demonstrates compliance with the EMAP standards that related to hazard mitigation planning are cross referenced in Table 3-6.

Table 3-6 EMAP Standards Crosswalk
Standard: 4.1 Hazard Identification, Risk Assessment and Consequence Analysis An Accredited Emergency Management Program has a Hazard Identification, Risk Assessment (HIRA), and Consequence Analysis.

Subsection 4.1.1 Location Notes
The Emergency Management Program
identifies the natural and human-caused
hazards that potentially impact the jurisdiction
using multiple sources. The Emergency
Management Program assesses the risk and
vulnerability of people, property, the
environment, and its own operations from these
hazards.

Section 4 (pgs. 4-1
to 4-194)
See Section 4.1 for identification of
natural hazards, summarized in Table
4-2. Sections 4.3.1 through 4.3.15 assess
the risk and vulnerability from each
identified hazard. These are organized in
alphabetical order.

Subsection 4.1.2 Location Notes

4.1.2 The Emergency Management Program
conducts a consequence analysis for the
hazards identified in Standard 4.1.1 to
consider the impact on the following:

Section 4.3.1
through 4.3.15 (pgs.

4.21 to 4.194)
See the Vulnerability Assessment section
of each hazard profile.
(1) public “People” subsection
(2) responders “Government Services” subsection
(3) continuity of operations including continued
delivery of services
“Government Services” subsection
(4) property, facilities, and infrastructure “General Property” and “Critical Facilities and Infrastructure” subsections
(5) environment “Historic, Cultural and Natural Resources” subsection
(6) economic condition of the jurisdiction “Economy” subsection (7) public confidence in the jurisdiction’s
governance
“Government Services” subsection
Subsection 4.1.3 Location Notes
The Emergency Management Program has a
maintenance process for its HIRA identified in
Standard 4.1.1 and the Consequence Analysis
identified in Standard 4.1.2, which includes a
method and schedule for evaluation and
revision.

Section 6.3 (pgs. 6-2
to 6-5)
See Subsection 6.3.2 Maintenance and
Evaluation Process for the maintenance
process and the method and schedule for
evaluation and revision.

Standard: 4.2 Hazard Mitigation
An Accredited Emergency Management Program has a mitigation program that regularly and systematically utilizes resources to mitigate the effects of emergencies/disasters associated with the risks identified in the HIRA. 842
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Subsection 4.2.1 Location Notes
The Emergency Management Program has a
plan to implement mitigation projects and sets
priorities based upon loss reduction.

Section 5 (pgs. 5-5
to 5-28) and Section
6 (pgs. 6-1 to 6-2)
See Section 5.3 for progress on
implementing the mitigation program to
date. See Section 5.2 on how actions
were prioritized. See Sections 6.2 for how
the plan will be implemented.
(1) The plan is based on the natural and
human-caused hazards identified in Standard

4.1.1 and the risk and consequences of those
hazards.

Section 5.2 and 5.3
(pgs. 5-5 to 5-28)
See Table 5-4 “Hazards” column for
hazards mitigated. See Section 5.2 for
how risk and consequences were
considered when developing and
prioritizing actions.
(2) The plan is developed through formal
planning processes involving Emergency
Management Program stakeholders.

Section 3 (pgs. 3-1
to 3-22)
Summarized in Table 3-2, Table 3-3 and
Table 3-4. See also Appendix A and
Appendix B for documentation.
(3) The plan establishes short and long-term
strategies, actions, goals, and objectives.

Section 5 (pgs. 5-1
to 5-28) and Section

6.3 (Insert pgs. 6-2
to 6-5)
See Table 5-4 “Priority” and “Timeline”
columns for short and long-term
strategies and actions.

Subsection 4.2.2 Location Notes
The Emergency Management Program
documents project ranking based upon the
greatest opportunity for loss reduction and
documents how specific mitigation actions
contribute to overall risk reduction.

Section 5.2.1 (pgs.
5-7 to 5-8), Section

5.2.2 (pgs. 5-12 to 5-
28) and Section 6.3
(pgs. 6-2 to 6-4)
See Prioritization subsection (pgs. 5-7 to
5-8) for how projects were ranked based
on loss reduction;
See Table 5-4 “Description/Background/
Benefits” column for how specific
mitigation actions contribute to overall
risk reduction;
See Maintenance and Monitoring
subsections (pgs. 6-2 to 6-4) for how the
contribution of specific actions will be
tracked and documented.

Subsection 4.2.3 Location Notes
The Emergency Management Program has a
process to monitor overall progress of the
mitigation activities and documents completed
initiatives and their resulting reduction or
limitation of hazard impact on the jurisdiction.

Section 6.3 (pgs. 6-2
to 6-4)
See Maintenance and Monitoring
subsections (pgs. 6-2 to 6-4) for how
progress will be tracked and
documented.

Subsection 4.2.4 Location Notes
The Emergency Management Program,
consistent with the scope of the mitigation
program, does the following: --- ---
(1) identifies ongoing mitigation opportunities
and tracks repetitive loss;
Section 4.3.8, Flood
Hazards – Insurance
Coverage, Claims
Paid, and Repetitive
Loss Properties
(under Flood Hazard
Profile) (pgs. 4-115
to 4-117); Section

6.3 (pgs. 6-2 to 6-4)
See Maintenance and Monitoring
subsection (pgs. 6-2 to 6-4)
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(2) provides technical assistance in
implementing mitigation codes and
ordinances;
Section 6.2 (pgs. 6-1
to 6-2) and Section

6.3 (pgs. 6-3 to 6-4)
See Role of the Planning Committee in
Plan Adoption, Implementation and
Maintenance subsection (pgs. 6-1 to 6-2),
and Incorporation into Existing Planning
Mechanisms (pgs. 6-3 to 6-4)
(3) participates in jurisdictional and
multijurisdictional mitigation efforts.

Section 3.3 to 3.4
(pgs. 3-4 to 3-7);
Section 5.3.2 (pgs.
5-12 to 5-28);
Section 6.2 to 6.3
(pgs. 6-1 to 6-4);
Section 7.1 (pg. 7-1)
See 3.4.2 Coordinate with Other
Departments and Agencies (pgs. 3-14 to
3-15), and Table 5-4 “Lead Agency and
Partners” column.

Subsection 4.2.5 Location Notes
The Emergency Management Program has a
maintenance process for the plan identified in
Standard 4.2.1, which includes a method and
schedule for evaluation and revision.

Section 6.3 (pgs. 6-2
to 6-5)
See Maintenance and Monitoring
subsections (pgs. 6-2 to 6-5) for method
and schedule.
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4 HAZARD IDENTIFICATION AND RISK ASSESSMENT
Requirement §201.6(c)(2)(i):

The risk assessment shall include a description of the type, location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.
§201.6(c)(2)(ii):

The risk assessment shall include a description of the jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section. This description shall include an overall summary of each hazard and its impact on the community. All plans approved after October 1, 2008 must also address NFIP insured structures that have been repetitively damaged by floods. The plan should describe vulnerability in terms of:
§201.6(c)(2)(ii)(A):

The types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas;
§201.6(c)(2)(ii)(B):

An estimate of the potential dollar losses to vulnerable structures identified in this section and a description of the methodology used to prepare the estimate. §201.6(c)(2)(ii)(C):

Providing a general description of land uses and development trends within the community so that mitigation options can be considered in future land use decisions.

Risk to natural hazards is a combination of hazard, vulnerability and capability. This section of the MJHMP will look at both hazards and vulnerability. The risk assessment process identifies and profiles relevant hazards and assesses the exposure to lives, property and infrastructure to these hazards. The goal of the risk assessment is to estimate the potential losses in Stanislaus County from a hazard event. This process also allows communities in Stanislaus County to better understand their potential risk to natural hazards and provides a framework for developing and prioritizing mitigation actions to reduce the risks from future hazard events in Stanislaus County.

The risk assessment process identifies and profiles relevant hazards and assesses the exposure of lives, property, and infrastructure to these hazards. The process allows for a better understanding of a jurisdiction’s potential risk to hazards and provides a framework for developing and prioritizing mitigation actions to reduce risk from future hazard events.

This risk assessment builds upon the methodology described in the 2013 FEMA Local Mitigation Planning Handbook, which recommends a four-step process for conducting a risk assessment:

1. Describe Hazards

2. Identify Community Assets

3. Analyze Risks

4. Summarize Vulnerability
In essence, the risk assessment evaluates potential loss from hazards by assessing the vulnerability of the County’s population, build environment, critical facilities, and other assets. The updated risk assessment also identifies natural and human-caused hazards and includes a consequence analysis for these hazards consistent with the Emergency Management Accreditation Program (EMAP) standards. Data collected through this process has been incorporated into the following sections of this section:
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Subsection 4.1: Hazard Identification—identifies the natural, human-caused, and human-health hazards that threaten the Planning Area and describes why some hazards have been omitted from further consideration.

Subsection 4.2: Asset Summary—describes the methodology for inventorying assets as the basis for determining vulnerability of the Planning Area to the identified hazards.

Subsection 4.3: Hazard Analysis, Risk Assessment, and Consequence Analysis—discusses the threat to the Planning Area and describes previous occurrences of hazard events and the likelihood of future occurrences (2013 FEMA Local Mitigation Planning Handbook Risk Assessment Step 1). It includes a vulnerability assessment considering assets at risk, critical facilities, and development trends (2013 FEMA Local Mitigation Planning Handbook Risk Assessment Steps 2, 3 and 4). The updated risk assessment also includes a consequence analysis that assesses the hazard impacts on the public; first responders; continuity of operations; property, facilities, and infrastructure; environment; economic conditions; and public confidence in government.

This risk assessment covers the entire geographical area of Stanislaus County. Since this plan is a multijurisdictional plan, the HMPC was required to evaluate how the hazards and risks vary from jurisdiction to jurisdiction. While these differences are noted in this section, they are expanded upon in the annexes of the participating jurisdictions. If no additional data is provided in an annex, it should be assumed that the risk and potential impacts to the affected jurisdiction are similar to those described here for the entire Stanislaus County Planning Area.

4.1 Hazard Identification
The San Joaquin Valley region and Stanislaus County are susceptible to a number of hazards. This MJHMP profiles the most significant of these hazards. In the early meetings with Stanislaus County and the HMPC, data was reviewed from the following sources on hazards affecting the County, those sources were: Federal and State Disaster Declaration History, the California State Hazard Mitigation Plan (SHMP) (2018), the Safety Element of the Stanislaus County 2015 General Plan, results from an initial risk assessment and hazard ranking exercise conducted by the Stanislaus County Office of Emergency Services (OES) in 2020 that addressed 48 natural and human-caused hazards, and interviews of staff that live and work in Stanislaus County.

Using existing natural hazards data and input gained through planning meetings during both the 2017 Local Hazard Mitigation Plan (LHMP) and 2021 update, the HMPC agreed upon a list of hazards that could affect Stanislaus County. The following table explains the changes in the hazards profiled in 2017 LHMP and the 2021 update.

Table 4-1 Updates to Hazards Profiled, 2017 LHMP and 2021 Update 2017 Hazards 2021 Hazards Comments
Earthquake Earthquake No Changes.

Landslide Landslide No Changes.

Dam Failure Dam Incidents No Changes.

Flood Flood No Changes.

Wildfire Wildfire No Changes.

Agriculture Pest and
Disease
New in 2021. Added due to significant
agricultural industry in the County and the
impacts to the local economy.

Aquatic Invasive Species
(AIS)
New in 2021. Added due to the worsening
AIS situation in the County, the nearby
region, and Northern California.

Cyber Attacks New in 2021. Added due to worldwide
uptick in number and extent of attacks.

Drought New in 2021. Profiled separately in 2021
Update due to the unique nature of the
hazard and the consequences on the
County.
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2017 Hazards 2021 Hazards Comments
Pandemic/Epidemic New in 2021. Included due to extent of impacts associated with the ongoing
COVID-19 pandemic.

Severe Weather: Hail,
Heavy Rain, Lightning
New in 2021. Included because severe
weather data and HMPC input show that
these events occur in the County regularly
and have caused damages.

Severe Weather: Wind,
Tornado
New in 2021. Included because weather
data and HMPC input show that these
severe weather events occur in the
County regularly and have caused
property damages.

Severe Weather: Dense
Fog
New in 2021. Included to assess the tule
fogs that cause issues for the County and
the San Joaquin Valley region.

The 2021 MJHMP update included a significant re-evaluation of the hazards with the latest, best available data. Hazards data from Stanislaus County, Cal OES, FEMA, the National Oceanic and Atmospheric Administration, and many other sources were examined to assess the significance of these hazards to the Planning Area. The update process included a comprehensive, parcel-level risk analysis with GIS where available data permitted. Many new maps and tables were added that capture the potential losses.

4.1.1 Overall Hazard Significance Summary
Overall hazard significance was based on a combination of Geographic Area, Probability of Future Occurrence and Potential Magnitude/Severity as defined below. The individual ratings are based on or interpolated from the analysis of the hazards in the sections that follow. During the 2021 Stanislaus County MJHMP update the individual ratings and significance of the hazards was revisited and updated. Public concern was also considered via input at public webinars, two public workshops, and an online survey.

Table 4-2 Stanislaus County Hazard Significance
Hazard Geographic
Area
Probability of
Future Occurrence
Magnitude/Severity
(Extent)
Overall
Significance
Agriculture Pest and Disease Extensive Likely Limited Low Aquatic Invasive Species Limited Likely Negligible Low
Cyber Attack Significant Likely NA Medium
Dam Incidents Significant Unlikely Catastrophic Medium
Drought Extensive Likely Critical High
Earthquake Extensive Occasional Critical Medium
Extreme Temperatures: Freeze
and Extreme Heat Extensive Highly Likely Critical High
Flood Significant Likely Critical Medium
Landslide Significant Occasional Negligible Low
Public Health Hazards:

Pandemic/Epidemic Extensive Occasional Critical High
Severe Weather: Dense Fog Extensive Likely Critical Medium Severe Weather: Heavy Rain,
Thunderstorm, Hail, and Lightning Extensive Highly Likely Critical High Severe Weather: High Wind and
Tornado Extensive Highly Likely Critical High
Wildfire Significant Occasional Negligible Medium
Geographic Area
Limited: Less than 10% of planning area
Significant: 10-50% of planning area
Extensive: 50-100% of planning area
Probability of Future Occurrences
Highly Likely: Near 100% chance of
occurrence in next year or happens every year.

Magnitude/Severity (Extent)
Catastrophic—More than 50 percent of property severely
damaged; shutdown of facilities for more than 30 days; and/or multiple deaths
Critical—25-50 percent of property severely damaged; shutdown of facilities for at least two weeks; and/or injuries and/or illnesses result in permanent disability
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Hazard Geographic
Area
Probability of
Future Occurrence
Magnitude/Severity
(Extent)
Overall
Significance
Likely: Between 10 and 100% chance of
occurrence in next year or has a recurrence
interval of 10 years or less.

Occasional: Between 1 and 10% chance of
occurrence in the next year or has a
recurrence interval of 11 to 100 years.

Unlikely: Less than 1% chance of occurrence
in next 100 years or has a recurrence interval
of greater than every 100 years.

Limited—10-25 percent of property severely damaged;
shutdown of facilities for more than a week; and/or
injuries/illnesses treatable do not result in permanent disability Negligible—Less than 10 percent of property severely damaged, shutdown of facilities and services for less than 24 hours; and/or injuries/illnesses treatable with first aid
Significance
Low: minimal potential impact
Medium: moderate potential impact
High: widespread potential impact

4.1.2 Non-Profiled Hazards
The HMPC reviewed data and discussed several other hazards, which were eliminated from further discussion because they occur rarely and/or their impacts are not significant. The list below details these hazards and provides a brief explanation for their omission from further profiling. • Avalanche – Snowfall is extremely rare to nonexistent across the Planning Area. • Coastal Erosion/Storm – This hazard does not occur due to distance from coasts and the ocean. • Hurricane – This hazard does not occur due to distance from ocean. • Tsunami – This hazard does not occur due to distance from ocean. • Volcano – The U.S. Geological Survey (USGS) does not include Stanislaus County in their map of areas identified as subject to hazards from potential eruptions in California.

The HMPC acknowledges there are other human-caused hazards that can affect the County. They are recognized in this MJHMP and risk assessment, with notes below how they are considered as consequences of other hazards or how they addressed in other State or County planning mechanisms:
• Civil Unrest and Terrorism – More commonly addressed in the local emergency operations plans (EOPs).
• Power outages/Utility Failure – This is addressed as a consequence of other hazards such as severe weather, earthquakes, and wildfires.
• Transportation Hazards – Transportation safety is typically addressed in other planning mechanisms.

Transportation hazards are also noted as a consequence of other hazards where applicable, e.g. severe weather sections, earthquakes, floods.

4.1.3 Disaster Declaration History
One method to identify hazards is to look at the events that have triggered federal and/or state disaster declarations that included Stanislaus County. Federal and state disaster declarations may be granted when the severity and magnitude of an event surpasses the ability of the local government to respond and recover. Disaster assistance is supplemental and sequential. When the local government’s capacity has been surpassed, a state disaster declaration may be issued, allowing for the provision of state assistance.

Should the disaster be so severe that both the local and state governments’ capacities are exceeded, a federal emergency or disaster declaration may be issued allowing for the provision of federal assistance.

In other words, a presidential disaster declaration puts federal recovery programs in place to help disaster victims, business, and public agencies.

The federal government may issue a disaster declaration through FEMA, the U.S. Department of Agriculture (USDA), or the Small Business Administration (SBA). FEMA also issues emergency declarations, which are more limited in scope and without the long-term federal recovery programs of major disaster declarations (Farm Service Agency 2018). The quantity and types of damage are the determining factors.

This section focuses on state and federal disaster and emergency declarations.

The communities throughout Stanislaus are among the many in California that are susceptible to disaster.

Details on federal and state disaster declarations were obtained by the HMPC, FEMA, and Cal OES and compiled in chronological order in Table 4-3. A review of state and federal declared disasters indicates that Stanislaus County received 16 proclamations between 1950 and March 2020. Of the 16 declarations, four were associated with severe storm(s); three were for flood; two were for freezing; another two were for fire; 848
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and another two were for the COVID-19 pandemic; one was for coastal storm, one was for hurricane and another one was for drought.

This disaster history (combined federal and state) suggests that Stanislaus County experiences a major event worthy of a disaster declaration about every few years. The County has a 23 percent chance of receiving a disaster declaration in any given year. With the exception of the declarations for drought and the COVID-19 pandemic, every declaration resulted directly or indirectly from severe weather. Further, a review of these events helps Stanislaus County, and its jurisdictions identify risk reduction targets and ways to improve capabilities to avoid large-scale hazard events in the future.

The following table lists the declarations where Stanislaus County was included in federal and/or state disaster declarations from 1950 to the present. Also included are Fire Management Assistance (FM) and Emergency Declarations (EM).

Table 4-3 Stanislaus County Disaster Declaration History 1950-present Hazard Type Disaster Name Disaster Number
Flood 1965 Heavy Rains & Flooding (Statewide) DR-183
Flood 1969 Severe Storms & Flooding (Multiple Counties) DR-253 Drought 1977 California Drought (Statewide) EM-3023
Coastal Storm 1983 Coastal Storms, Floods, Slides & Tornadoes (Multiple Counties)
DR-677
Freezing 1991 Severe Freeze (Multiple Counties) DR-894
Severe Storm(s) 1995 Severe Winter Storms, Flooding Landslides, Mud Flow (Multiple Counties)
DR-1046
Severe Storm(s) 1997 Severe Storms, Flooding, Mud and Landslides (Statewide) DR-1155 Severe Storm(s) 1998 Severe Winter Storms and Flooding (Statewide) DR-1203 Hurricane 2005 Hurricane Katrina Evacuation (Statewide) EM-3248 Severe Storm(s) 2006 Severe Storms, Flooding, Landslides, and Mudslides (Statewide)
DR-1646
Freezing 2007 Severe Freeze (Multiple Counties) DR-1689 Flood 2017 Severe Winter Storms, Flooding, and Mudslides (Statewide)
DR-4308
Biological 2020 Covid-19 EM-3428
Biological 2020 COVID-19 pandemic DR-4482
Fire 2020 Santa Clara Unit (SCU) Lightning Complex Fire FM-5338 Fire 2020 Wildfires (Multiple Counties) DR-4558
Source: Stanislaus OES, Cal OES and FEMA
Since 2012, there have been 21 disaster designations issued by the Secretary of Agriculture in Stanislaus County, 16 of which were for drought and three were for excessive rain, of which one was also for high winds, hail, excess rain, and cold temperatures. Of the drought designations, 11 are classified as “DroughtFast Track” Secretarial disaster designations. According to the Secretary of Agriculture, a Fast Track designation is for a severe drought and provides an automatic designation when during the growing season any portion of the County meets the severe drought intensity value for eight consecutive weeks. Refer to the Drought hazard profile for more information of disaster declarations from the Secretary of Agriculture related to drought events.

Table 4-4 USDA Agricultural Declarations in Stanislaus County, 2012-2020 Year Hazard Designation Number Approval Date
2012
Drought S3248 5/31/2012
Drought-Fast Track S3268 7/12/2012
Hailstorm, rain, cold temperatures S3320 8/3/2012
Drought S3379 9/5/2012
2013
Drought S3452 12/19/2012
Drought-Fast Track S3547 7/3/2013
Drought-Fast Track S3558 7/31/2013
Drought-Fast Track S3569 8/21/2013
2014 Drought-Fast Track S3626 1/15/2014
Drought S3743 9/17/2014
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Year Hazard Designation Number Approval Date
2015 Drought-Fast Track S3784 2/4/2015
Drought S3943 12/23/2015
2016 Drought-Fast Track S3952 2/17/2016
Severe weather including excessive rainfall and high winds S4164 3/31/2017 2017 Excessive rain, high winds, cold temperatures, and hail S4170 4/28/2017 2017 Drought-Fast Track S4144 2/23/2017
2020 Drought-Fast Track S4163 3/22/2017
Excessive rain S4237 10/13/2017
2019 Excessive rain S4656 3/11/2020
2020 Drought-Fast Track S4697 6/16/2020
2021* Drought-Fast Track S4916 3/5/2021
Source: USDA Secretary of Agriculture
*2021 data is as of August 20, 2021.

4.1.4 Climate Change Considerations Summary
Stanislaus County is part of the San Joaquin Valley part of California’s Central Valley. The region is known as one of the world’s most productive agricultural regions and is also vulnerable to the impacts of climate change. The following are highlights from California’s Fourth Climate Change Assessment, San Joaquin Valley Region Report (Preview), of projected impacts to the State of California and the Central Valley due to climate change:
• Acceleration of higher temperatures across California. • More intense and frequent heat waves.
• Increasing evapotranspiration.
• More intense and frequent droughts.
• More intense rainstorms.
• Higher frequency of catastrophic floods.
• More severe and frequent wildfires.
• Declining and change in timing of snowmelt.
• Increased susceptibility to rain-on-snow events from atmospheric rivers. • Increased stream temperatures resulting in decreased water quality.

In addition, the 2017 Stanislaus County Climate Change and Health Profile Report, supported by the Center for Disease Control (CDC) and California Department of Public Health (CDPH) summarized climate projections specifically to the Northern Central Valley region, which includes Stanislaus County. These projections align with those mentioned in the California’s Fourth Climate Change Assessment, San Joaquin Valley Region Report (Preview). The 2017 Stanislaus County Climate Change and Health Profile Report made the following findings related to temperature changes:
• Temperatures are expected to rise substantially throughout this century. • Average annual temperature is projected to increase from 60.6 °F to 64.6 °F (under the low-emissions scenario) or 67.2 °F (under the high-emission scenario).

Both the California’s Fourth Climate Change Assessment and the 2017 Stanislaus County Climate Change and Health Profile Report contain data derived from web-based Cal-Adapt tool, which was used to summarize the projected changes through the end of the century. Cal-Adapt is a scenario planning tool that was developed by the California Energy Commission (CEC) and the University of California, Berkeley Geospatial Innovation Facility. The Cal-Adapt tool uses global climate simulation model data downscaled to a local and regional resolution to identify localized impacts. The Cal-Adapt tool makes predictions under two Representative Concentration Pathways (RCP) scenarios. RCP scenarios are not specific policies but defined by the total solar radiative focusing anticipated by 2100 and address the uncertainty in future concentrations of greenhouse gas (GHG) emissions. Each RCP scenario is described below:
• RCP 4.5 – a low-emissions scenario, which assumes that emissions peak around 2040 and then decline, and
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• RCP 8.5 – a high-emissions scenario, which assumes that emissions continue to rise strongly through 2030 and plateau around 2100. Climate change projected under RCP 8.5 will typically be more severe than under RCP 4.5.

Both scenarios help municipalities in California assess emissions-dependent variability and evaluate a moderate scenario alongside a worst-case scenario. The important consideration for hazard mitigation is that climate change is exacerbating the hazards that are already identified and profiled. Additional specifics associated with the hazards are discussed in the Climate Change Considerations portion of each hazard profile. The County and California are also already experiencing the impacts of climate change including prolonged drought, increased flooding due to shifts in peak runoff, increased average temperatures, shifts in the water cycle, and changes to precipitation patterns and the intensity of extreme events resulting from hazards. Climate change not only results in progressive changes, such as shifting weather patterns but also affects the frequency and severity of hazard events (SHMP 2018). Furthermore, climate change also generates an increase in the variance of climate patterns, and this increased variance creates challenges for hazards planning, which previously used historic recurrence rates to predict future events, and now must incorporate changes to the frequency, severity, and location due to climate change.

Risk assessment for hazards is built upon the frequency of past events and the assumption that historic occurrence rates are a good predictor of future event probability. With climate change, however, history is not an adequate predictor of the probability of future occurrences (SHMP 2018). Planning for climate change (and understanding the probability of future occurrences [see Subsection 4.3 below]) is therefore now based on understanding and integrating evolving climate change science and modeled projections that account for shifts in historic conditions due to climate change (SHMP 2018) into hazard mitigation planning.

Additional specifics associated with the hazards are discussed in the Climate Change Considerations subsection of each hazard profile.

4.1.5 Overview of Hazard Identification, Risk Assessment, and Consequence Analysis Subsection 4.3 contains detailed hazard profiles for the identified hazards. Each hazard profile includes the following subsections:
• Hazard/Problem Definition – This section gives a description of the hazard and associated issues followed by details on the hazard specific to the Stanislaus County Planning Area. • Geographic Area – This section gives a spatial description of the potential location or areas of Stanislaus County where the hazard expected to impact.
• Extent (Magnitude/Severity) – This section gives a description of the potential strength or magnitude of the hazard as it pertains to Stanislaus County. It describes how much damage could occur as a result of a hazard event.
• Previous Occurrences – This section contains information on historical incidents, including impacts where known. Historical incident worksheets were used to capture information from participating jurisdictions on past occurrences.
• Probability of Future Occurrence – The frequency of past events is used in this section to gauge the likelihood of future occurrences. Where possible, frequency was calculated based on existing data. It is determined by dividing the number of events observed by the number of years on record and multiplying by 100. This gives the percent chance (probability) of an event happening in any given year (e.g., three droughts over a 30-year period equates to a 10 percent chance of a drought in any given year). The likelihood of future occurrences is categorized into one of the following classifications:
Highly Likely – Near 100 percent chance of occurrence in next year or happens every year. Likely – Between 10 and 100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less.
Occasional – Between 1 and 10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years.
Unlikely – Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.
• Climate Change Considerations – This describes the potential for climate change to affect the frequency and intensity of the hazard in the future.
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• Vulnerability – Following the hazard profiles is a vulnerability assessment for each identified hazard.

The assessment was conducted through the study of potential impacts to the following specific sectors, including those sectors assessed in a Consequence Analysis:
General Property
People (including the public)
Government Services (including the public’s confidence in governance) Critical Facilities and Infrastructure (including the continuity of operations) Economy
Historic, Cultural, and Natural Resources
Future Development
Risk Summary – Each vulnerability assessment includes a risk summary of the key issues/problems based on threat, vulnerability and consequence to the Planning Area and jurisdictions from the specific hazard.

Vulnerabilities are summarized for all natural hazards, and the consequences are summarized for both natural hazards, public health hazards, and human-caused hazards in a consequence analysis. The vulnerability assessment addresses who or what is vulnerable to natural hazards or climate stressors, where is someone or a critical facility susceptible to damage, and when and why these assets may be vulnerable. The assessment is used to inform strategic decision-making by identifying the assets or portions of the Planning Area most vulnerable to natural hazards.

The consequence analysis addresses impacts on the public; first responders; continuity of operations; property, facilities, and infrastructure; the environment; economic conditions; and public confidence in governance. The government services section assesses the impacts on the first responders and public confidence in governance. The other sections cover the public, continuity of operations, property, environment, and economy.

Data used to support this assessment included the following:
• County GIS data (hazards, base layers, and assessor’s data); • Statewide and nationwide GIS datasets to support mitigation planning; • California SHMP 2018;
• Stanislaus County LHMP 2017;
• Neighboring Jurisdictional HMPs;
• Cal FIRE datasets;
• California’s Fourth Climate Change Assessment;
• Written descriptions of inventory and risks provided by the jurisdictions; • Online data sources (cited where applicable);
• Data and information from existing plans and studies; and • Input from the HMPC members and staff from the County and local, state, and federal agencies.

4.2 Asset Summary

4.2.1 Assets Exposure
As a starting point for analyzing the Planning Area’s vulnerability to identified hazards, the HMPC used a variety of data to define a baseline against which all disaster impacts could be compared. If a catastrophic disaster was to occur in the Planning Area, this section describes significant assets exposed or at risk in the Planning Area. Data used in this baseline assessment included:
• Total assets at risk;
• Critical facility inventory;
• Cultural, historical, and natural resources; and
• Population growth and land use/development trends.
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Total Assets at Risk
Building value assessments in this plan are based on data from the Stanislaus County’s Assessor’s Office.

This data provided the baseline for an inventory of the total exposure of developed properties within the County and helps to ensure that the updated MJHMP reflects changes in development. It is important to note that depending on the nature and type of hazard event or disaster, it is generally the value of the infrastructure or improvements to the parcels that are of concern or at risk. Generally, the land itself is not a total loss, but may see a reduction in value. Thus, the parcel analysis excludes land value.

Parcel Exposure and Preparations for Analysis
Stanislaus County Assessor data was used to inventory the total number and types of parcels with improvements, defined as parcels with an improvement value greater than zero in the County. Building content values were estimated based on the following formulas based on FEMA/Hazus methods: a) Residential properties received content values worth 50% of the improved values; b) Agricultural, Commercial, Exempt, and Mixed Use related properties received content values worth 100% of the improved values; and c) Industrial properties received content values worth 150% of the improved values.

Adding up these content and original improved values yields the Total Value of Improved Parcels, which is an estimation of the total property exposure within the County. Table 4-6 summarizes the property inventory for the County and each participating jurisdiction with detail by property type. Table 4-5 shows the total property inventory from the Assessor’s Office.

Table 4-5 Total Exposure Summary by Jurisdiction
Jurisdiction Improved
Parcel Count Improved Value Estimated Content Value Total Value Ceres 11,462 $2,511,485,475 $1,760,538,649 $4,272,024,124 Hughson 2,086 $494,398,275 $313,490,178 $807,888,453
Modesto 60,673 $14,126,321,781 $9,767,800,876 $23,894,122,657 Newman 3,385 $590,163,657 $344,071,684 $934,235,341
Oakdale 7,298 $1,685,764,252 $1,150,181,302 $2,835,945,554 Patterson 6,318 $1,771,624,046 $1,230,025,611 $3,001,649,657 Riverbank 6,757 $1,405,026,457 $847,415,697 $2,252,442,154 Turlock 19,413 $5,311,625,963 $3,985,984,895 $9,297,610,858 Waterford 2,376 $389,884,917 $233,731,703 $623,616,620
Unincorporated 33,626 $8,094,078,660 $7,355,080,468 $15,449,159,128 Total 153,394 $36,380,373,483 $26,988,321,061 $63,368,694,544 Source: Stanislaus County Assessor’s Office, Wood Analysis Table 4-6 Total Exposure by Jurisdiction and Property Type Jurisdiction
Property Type Improved
Parcel
Count
Improved Value Estimated
Content Value Total Value
Ceres
Commercial 295 $274,772,405 $274,772,405 $549,544,810
Industrial 207 $249,762,103 $374,643,155 $624,405,258
Non-Assessable 5 $938,099 $938,099 $1,876,198
Residential 10,555 $1,721,767,451 $860,883,726 $2,582,651,177 Residential-Income 75 $29,383,391 $14,691,696 $44,075,087 Rural, Farm,
Agricultural
16 $1,426,848 $1,426,848 $2,853,696
Unclassified 272 $230,204,065 $230,204,065 $460,408,130 Vacant Commercial 34 $2,726,199 $2,726,199 $5,452,398
Vacant Residential 3 $504,914 $252,457 $757,371
Total 11,462 $2,511,485,475 $1,760,538,649 $4,272,024,124 Hughson Commercial 76 $88,461,818 $88,461,818 $176,923,636 Industrial 20 $19,160,207 $28,740,311 $47,900,518
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Jurisdiction
Property Type Improved
Parcel
Count
Improved Value Estimated
Content Value Total Value
Residential 1,929 $376,068,623 $188,034,312 $564,102,935 Residential-Income 22 $4,907,515 $2,453,758 $7,361,273
Rural, Farm,
Agricultural
6 $562,163 $562,163 $1,124,326
Unclassified 23 $4,935,480 $4,935,480 $9,870,960
Vacant Commercial 9 $302,206 $302,206 $604,412
Vacant Residential 1 $263 $132 $395
Total 2,086 $494,398,275 $313,490,178 $807,888,453
Modesto
Commercial 2,071 $3,304,473,791 $3,304,473,791 $6,608,947,582 Industrial 318 $396,367,700 $594,551,550 $990,919,250
Non-Assessable 6 $2,427,991 $2,427,991 $4,855,982
Residential 55,011 $9,002,867,528 $4,501,433,764 $13,504,301,292 Residential-Income 510 $109,144,569 $54,572,285 $163,716,854 Rural, Farm,
Agricultural
12 $1,448,594 $1,448,594 $2,897,188
Unclassified 2,606 $1,288,060,077 $1,288,060,077 $2,576,120,154 Vacant Commercial 120 $20,134,118 $20,134,118 $40,268,236 Vacant Residential 19 $1,397,413 $698,707 $2,096,120
Total 60,673 $14,126,321,781 $9,767,800,876 $23,894,122,657 Newman
Commercial 100 $35,962,668 $35,962,668 $71,925,336
Industrial 36 $18,733,108 $28,099,662 $46,832,770
Residential 3,172 $507,471,566 $253,735,783 $761,207,349 Residential-Income 26 $2,781,981 $1,390,991 $4,172,972
Rural, Farm,
Agricultural
4 $373,507 $373,507 $747,014
Unclassified 33 $24,092,050 $24,092,050 $48,184,100
Vacant Commercial 10 $85,269 $85,269 $170,538
Vacant Residential 4 $663,508 $331,754 $995,262
Total 3,385 $590,163,657 $344,071,684 $934,235,341
Oakdale
Commercial 327 $202,961,845 $202,961,845 $405,923,690
Industrial 208 $153,308,947 $229,963,421 $383,272,368
Non-Assessable 3 $60,695 $60,695 $121,390
Residential 6,355 $1,210,767,189 $605,383,595 $1,816,150,784 Residential-Income 64 $13,323,410 $6,661,705 $19,985,115 Rural, Farm,
Agricultural
17 $4,549,891 $4,549,891 $9,099,782
Unclassified 292 $99,950,578 $99,950,578 $199,901,156
Vacant Commercial 27 $457,449 $457,449 $914,898
Vacant Residential 5 $384,248 $192,124 $576,372
Total 7,298 $1,685,764,252 $1,150,181,302 $2,835,945,554 Patterson
Commercial 169 $115,891,266 $115,891,266 $231,782,532
Industrial 72 $99,219,330 $148,828,995 $248,048,325
Residential 5,889 $1,157,277,335 $578,638,668 $1,735,916,003 Residential-Income 73 $11,291,796 $5,645,898 $16,937,694 Rural, Farm,
Agricultural
31 $3,007,864 $3,007,864 $6,015,728
Unclassified 61 $370,566,992 $370,566,992 $741,133,984
Vacant Commercial 16 $522,393 $522,393 $1,044,786
Vacant Residential 7 $13,847,070 $6,923,535 $20,770,605 Total 6,318 $1,771,624,046 $1,230,025,611 $3,001,649,657 Riverbank Commercial 242 $134,243,147 $134,243,147 $268,486,294 854
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Jurisdiction
Property Type Improved
Parcel
Count
Improved Value Estimated
Content Value Total Value
Industrial 36 $36,455,827 $54,683,741 $91,139,568
Non-Assessable 1 $16,336 $16,336 $32,672
Residential 6,294 $1,144,317,711 $572,158,856 $1,716,476,567 Residential-Income 51 $7,178,599 $3,589,300 $10,767,899 Rural, Farm,
Agricultural
22 $2,897,415 $2,897,415 $5,794,830
Unclassified 93 $79,144,886 $79,144,886 $158,289,772
Vacant Commercial 14 $591,499 $591,499 $1,182,998
Vacant Residential 4 $181,037 $90,519 $271,556
Total 6,757 $1,405,026,457 $847,415,697 $2,252,442,154
Turlock
Commercial 832 $924,925,946 $924,925,946 $1,849,851,892 Industrial 357 $579,530,828 $869,296,242 $1,448,827,070 Non-Assessable 4 $244,121 $244,121 $488,242
Residential 17,103 $3,163,378,554 $1,581,689,277 $4,745,067,831 Residential-Income 227 $61,684,538 $30,842,269 $92,526,807 Rural, Farm,
Agricultural
72 $8,988,896 $8,988,896 $17,977,792
Unclassified 739 $556,407,740 $556,407,740 $1,112,815,480 Vacant Commercial 60 $10,715,467 $10,715,467 $21,430,934 Vacant Residential 19 $5,749,873 $2,874,937 $8,624,810
Total 19,413 $5,311,625,963 $3,985,984,895 $9,297,610,858 Waterford
Commercial 117 $38,179,265 $38,179,265 $76,358,530
Industrial 18 $4,182,790 $6,274,185 $10,456,975
Residential 2,114 $311,482,233 $155,741,117 $467,223,350 Residential-Income 29 $5,006,986 $2,503,493 $7,510,479
Rural, Farm,
Agricultural
20 $2,708,574 $2,708,574 $5,417,148
Unclassified 76 $28,263,326 $28,263,326 $56,526,652
Vacant Commercial 2 $61,743 $61,743 $123,486
Total 2,376 $389,884,917 $233,731,703 $623,616,620
Unincorporated
Commercial 798 $597,932,090 $597,932,090 $1,195,864,180 Industrial 952 $1,322,266,361 $1,983,399,542 $3,305,665,903 Non-Assessable 28 $49,799,273 $49,799,273 $99,598,546
Residential 16,992 $2,737,798,000 $1,368,899,000 $4,106,697,000 Residential-Income 477 $60,911,214 $30,455,607 $91,366,821 Rural, Farm,
Agricultural
13,863 $3,114,041,506 $3,114,041,506 $6,228,083,012
Unclassified 384 $206,801,166 $206,801,166 $413,602,332 Vacant Commercial 94 $2,975,519 $2,975,519 $5,951,038
Vacant Residential 38 $1,553,531 $776,766 $2,330,297
Total 33,626 $8,094,078,660 $7,355,080,468 $15,449,159,128 Grand Total 153,394 $36,380,373,483 $26,988,321,061 $63,368,694,544 Source: Stanislaus County Assessor’s Office, Wood Analysis Critical Facility/Lifeline Inventory
A significant aspect of the 2021 HIRA update was the update of critical facilities and an alignment/classification with the FEMA Lifelines framework. The critical facilities/lifelines GIS database was based on a combination of County-provided data, Homeland Infrastructure Foundation-Level Data (HIFLD), and local and jurisdiction-specific input. Jurisdictions were able to review critical facility data, edit descriptive 855
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attributes and address information, and add new critical facilities. The results are summarized here and provided the basis for GIS-based vulnerability analyses, where data permitted.

For the purposes of this plan, a critical facility is defined as one that is essential in providing utility or direction either during the response to an emergency or during the recovery operation. FEMA sorts critical facilities into seven lifeline categories as shown in Figure 4-1.

Figure 4-1 Lifeline Categories
Source: FEMA 2020.

These lifeline categories standardize the classification of critical facilities and infrastructure that provide indispensable service, operation, or function to a community. A lifeline is defined as providing indispensable service that enables the continuous operation of critical business and government functions, and is critical to human health and safety, or economic security. These categorizations are particularly useful as they:
• Enable effort consolidations between government and other organizations (e.g., infrastructure owners and operators).
• Enable integration of preparedness efforts among plans, easier identification of unmet critical facility needs.
• Refine sources and products to enhance awareness, capability gaps, and progress towards stabilization.
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• Enhance communication amongst critical entities, while enabling complex interdependencies between government assets.
• Highlight lifeline related priority areas regarding general operations as well as response efforts.

Table 4-7 shows a summary of the critical facilities inventory grouped by lifeline. Figure 4-2 illustrates the location of critical facilities in Stanislaus County.

Table 4-7 Summary of Critical Facilities by Jurisdiction and Lifeline Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Ceres 17 4 2 1 9 14 14 61
Hughson 1 - 17 1 2 10 3 34
Modesto 52 24 25 9 112 90 32 344
Newman - - - - - - - -
Oakdale - - - 1 1 1 - 3
Patterson - - 1 - - - - 1
Riverbank - 1 - 1 - - 1 3
Turlock 13 7 13 21 27 23 20 124
Waterford - - 6 - - 7 3 16
Unincorporated 107 40 18 27 14 59 153 418
Other Counties 1 - - - 1 - - 2
Total 191 76 82 61 166 204 226 1,006
Sources: HIFLD, National Inventory of Dams (NID), Department of Water Resources (DWR), Stanislaus County, City of Hughson, City of Newman
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Figure 4-2 Stanislaus County Critical Facilities
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Other critical facilities unique to the County are the California Aqueduct, Hetch Hetchy Aqueduct, the DeltaMendota Canal, and the NASA Crows Landing Airport. These facilities are better addressed in the EOPs for the County and federal emergency plans.

The California Aqueduct, part of the California State Water Project, runs through the western part of Stanislaus County. The State Water Project is a water storage and delivery system of reservoirs, aqueducts, power plants, and pumping plants. Its main purpose is to store water and distribute it to 29 urban and agricultural water suppliers in Northern California, the San Francisco Bay Area, the San Joaquin Valley, the Central Coast, and Southern California. Seventy percent of the contracted water supply goes to urban users and thirty percent goes to agricultural users. The State Water Project makes deliveries to two-thirds of California's population. Earthquakes, landslides, flooding, or other hazard events that disrupt the aqueduct’s ability to deliver water could have serious impacts to agriculture in the County and water users in many areas of California.

Cultural, Historical and Natural Resources
Assessing Stanislaus County’s vulnerability to disaster also involves inventorying the natural, historical, and cultural assets of the area. This step is important for the following reasons:
• The community may decide that these types of resources warrant a greater degree of protection due to their unique and irreplaceable nature and contribution to the overall economy. • In the event of a disaster, an accurate inventory of natural, historical, and cultural resources allows for more prudent care in the disaster’s immediate aftermath when the potential for additional impacts is higher.
• The rules for reconstruction, restoration, rehabilitation, and/or replacement are often different for these types of designated resources.
• Natural resources can have beneficial functions that reduce the impacts of natural hazards, for example, wetlands and riparian habitat which help absorb and attenuate floodwaters and thus support overall mitigation objectives.

Historic and Cultural Resources
Historical resources are buildings, structures, objects, places, and areas that are eligible for listing in the National Register of Historic Places (NRHP), the California Register of Historic Resources (CRHR), or the County’s List of Historic Resources, have an association with important persons, events in history, or cultural heritage, or have distinctive design or construction method.

For purpose of federal actions, a qualified historic resource is defined as a property listed in or formally determined eligible for listing in the NRHP before a disaster occurs. The NRHP is part of a national program to coordinate and support public and private efforts to identify, evaluate, and protect historic and archeological resources. Properties listed include districts, sites, buildings, structures, and objects that are significant in American history, architecture, archeology, engineering, and culture. The National Register is administered by the U.S. Department of the Interior National Park Service. Local and state agencies may consider a broader definition of qualified historic properties in the review, evaluation, and treatment of properties damaged during a disaster.

The State of California Office of Historic Preservation can provide technical rehabilitation and preservation services for historic properties affected by a natural disaster. Depending on the hazard, protection could range from emergency preparedness, developing a fire safe zone around sites susceptible to wildfires, or seismically strengthening or structurally reinforcing structures.

State and local registers of historic resources provide designated Historical Landmarks, Points of Historical Interest, and Historic Buildings. These resources include, but are not limited to:
• The California Register of Historical Resources
• The California Historical Landmarks
• The California Inventory of Historical Resources
• The California Points of Historical Interest
Historical Resources designated on a federal, state or local level are listed in Table 4-8. 859
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Table 4-8 Stanislaus County Historical Resources
Property Name Register Jurisdiction Date Listed
Hotel Covell National Modesto 12/29/1994
Kingen Hotel National La Grange 8/24/1979
Knights Ferry National & State Historical Landmark Knights Ferry 8/8/1939 La Grange State Historical Landmark La Grange 11/15/1948 La Grange Dam Point of Interest La Grange 7/31/1979
Louie's Place National La Grange 8/24/1979
Mchenry Mansion National Modesto 4/4/1978
Mchenry Mansion Point of Interest Modesto 7/31/1979
Odd Fellows Hall National La Grange 8/24/1979
Old Adobe Barn National La Grange 8/24/1979
Old La Grange Schoolhouse National La Grange 8/24/1979
Paradise Point of Interest Modesto 7/31/1979
Patterson Branch Library National Patterson 12/10/1990
Plaza Building National Patterson 1/6/2004
Riverbank Branch Library National Riverbank 10/10/1996
Shell Gas Station National La Grange 8/24/1979
St. Louis Catholic Church National La Grange 8/24/1979
Stage Stop National La Grange 8/24/1979
Temporary Detention Camps
for Japanese AmericansTurlock Assembly Center
State Historical Landmark Turlock 5/13/1980
Tuolumne City Point of Interest Westley 7/31/1979
Turlock Carnegie Library National Turlock 1/7/1993
Turlock High School
Auditorium and Gymnasium
National Turlock 1/11/1991
U.S. Post Office National Modesto 2/10/1983
Walton, Dr. Robert And Mary,
House
National Modesto 12/14/2006
Whitmore, Daniel, House National Ceres 4/5/1989
Willms Ranch State Historical Landmark Knights Ferry 11/15/1948 Wood, Walter B., House National Modesto 5/20/1988
Source: California Office of Historic Preservation
Other historic sites of local importance also exist. These include Gold Dredge, First National Bank of Oakdale Building and Bald Eagle Ranch House, which have local significance, based on the NRHP’s database, as well as the Knight’s Ferry Bridge, which has national significance.

Lists of designated historical resources change periodically, and they may not include those currently in the nomination process and not yet listed. Additionally, as defined by the National Environmental Policy Act (NEPA), any property over 50 years of age is considered a historic resource and is potentially eligible for the National Register. Thus, in the event that the property is to be altered, or has been altered, as the result of a major federal action, the property must be evaluated under the guidelines set forth by NEPA. Structural mitigation projects are considered alterations for the purpose of this regulation.

Cultural resources defined in California Environmental Quality Act (CEQA) Section 15064.5 as include prehistoric and historic archeological resources; historic-period resources (buildings, structures, area, place, or objects). Archeological resources reflect past human activity extending from Native American prehistoric cultures throughout the early 20th century. The artifacts left by previous occupants may be encountered in small to large residential sites, or special use areas.

Many cultural and historical resources in the County are vulnerable to several hazards due to location and the nature of their construction. Some of these risks include earthquakes, wildfires, or adverse weather.

Natural Resources
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sensitive natural resources. Inventory and awareness of natural resource assets is vital to meeting conservation objectives. For example, protecting wetland areas provides sensitive habitat protection as well as floodwater conveyance and storage, which further enhances public safety.

Established in 1987, the San Joaquin River National Wildlife Refuge is 7,000 acres in size and located in Stanislaus County. The Refuge is situated where three major rivers (Tuolumne, Stanislaus and San Joaquin) join in the San Joaquin Valley, creating a mix of habitats that provide ideal conditions for high wildlife and plant diversity. The Refuge was initially established primarily to protect and manage habitat for the Aleutian cackling goose – a federally listed endangered species at that time. Today, the Refuge is managed with a focus on migratory birds and endangered species, including Riparian Woodlands, Swainson’s hawks and Riparian Brush Rabbits.

To further understand natural resources that may be particularly vulnerable to a hazard event, as well as those that need consideration when implementing mitigation activities, it is important to identify at-risk species (endangered and threatened species) in the Planning Area. The U.S. Fish and Wildlife Service (USFW) maintains a list of federally listed threatened and endangered species for the country, which can be queried at the state or even county levels through the Information for Planning and Consultation (IPaC) database. The California Department of Fish and Wildlife (CDFW) also maintains species lists and accounts for threatened and endangered species. State and federal laws protect the habitat of these species through the environmental review process. Species of special concern may additionally include species that meets the State definition of threatened or endangered but has not been formally listed, experiences seriously population declines, or habitat decline, or has naturally small populations exhibiting high susceptibility to population decline (USFW 2019).

Table 4-9 summarizes Stanislaus County’s special status animal species as indicated in the IPaC database, within the Environmental Conservation Online System.

Table 4-9 Threatened and Endangered Species in Stanislaus County Group Common Name Scientific Name Status
Amphibians California tiger Salamander Ambystoma californiense Endangered California red-legged frog Rana draytonii Threatened
Birds
Yellow-billed Cuckoo Coccyzus americanus Threatened
California least tern Sterna antillarum browni Endangered Least Bell's vireo Vireo bellii pusillus Endangered
Crustaceans
Conservancy fairy shrimp Branchinecta conservatio Endangered Vernal pool fairy shrimp Branchinecta lynchi Threatened Vernal pool tadpole shrimp Lepidurus packardi Endangered Fishes Delta smelt Hypomesus transpacificus Threatened
longfin smelt Spirinchus thaleichthys Candidate
Flowering Plants
Chinese Camp brodiaea Brodiaea pallida Threatened
Colusa grass Neostapfia colusana Threatened
Fleshy owl's-clover Castilleja campestris ssp.
succulenta
Threatened
Greene's tuctoria Tuctoria greenei Endangered
Hairy Orcutt grass Orcuttia pilosa Endangered
Hartweg's golden sunburst Pseudobahia bahiifolia Endangered Hoover's spurge Chamaesyce hooveri Threatened
Large-flowered fiddleneck Amsinckia grandiflora Endangered Red Hills vervain Verbena californica Threatened
San Joaquin Orcutt grass Orcuttia inaequalis Threatened Santa Clara Valley dudleya Dudleya setchellii Endangered Insects
Monarch Butterfly Danaus plexippus Candidate
Valley elderberry longhorn
beetle
Desmocerus californicus
dimorphus Threatened
Mammals
Fresno kangaroo rat Dipodomys nitratoides exilis Endangered Riparian brush rabbit Sylvilagus bachmani riparius Endangered Riparian woodrat (=San
Joaquin Valley)
Neotoma fuscipes riparia Endangered
San Joaquin kit fox Vulpes macrotis mutica Endangered
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Group Common Name Scientific Name Status
Reptiles Blunt-nosed leopard lizard Gambelia silus Endangered Giant garter snake Thamnophis gigas Threatened
Source: Source: US Fish and Wildlife Service – Environmental Conservation Online System Growth and Development Trends
Population and Projected Growth
According to the Department of Finance (DOF) the 2020 population of Stanislaus County as a whole was 555,955. The DOF projects the total population will increase by 9% to 606,128 by 2030. While total households in the County are also projected to increase from 173,951 in 2020 to 193,658 in 2030, people per household is projected to slightly decrease from 3.19 in 2020 to 3.1 person per household in 2030. All of the incorporated communities, except Turlock (slight decrease -0.3), experienced an increase or no change in population between 2020 and 2021. The City of Modesto is also ranked No.38 among 482 California cities by the California DOF in 2020 – 2021 with a numeric increased change in population (+854).

Social Vulnerability
Social vulnerability considerations were included in the update of this plan in 2021 to identify areas across the County that might be more vulnerable to hazard impacts based on a number of factors. A social vulnerability index (SoVI) was developed by the CDC Agency for Toxic Substances and Disease Registry (ATSDR) and their Geospatial Research, Analysis & Services Program teams, as a way to portray communities’ capacities to prepare for and respond to natural and manmade disasters. The SoVI does so by providing insight into particularly vulnerable populations to in turn assist emergency response planners and even public health officials identify communities more likely to require additional support before, during, and after a hazardous event. The CDC’s SoVI create county- and state-level maps to show relative vulnerability and hence provide key socially and spatially relevant information on communities’ populations, and these maps compare the SoVI based on Census Tracts. The overall social vulnerability based on the SoVI data is shown for Stanislaus County by Census Tracts in Figure 4-3 below, based on statewide ranking. This overall index combines four main themes of vulnerability, namely: socioeconomic status; household composition and disability; minority status and language; and housing and transportation, which in turn are comprised of subcategories for a total of 15 variables accounting for various vulnerability factors.

For additional information on the CDC’s SoVI, refer to their documentation and materials online at https://svi.cdc.gov/. Based on this data, the areas with the highest level of social vulnerability in the County are in the central, southern and southwestern portions, including some of the incorporated jurisdictions such as the cities of Modesto, Ceres, and Turlock.

In California, socially vulnerable populations, also referred to as disadvantaged communities (DACs) are mapped through several State-developed mapping tools, including but not limited to the Delta Social Vulnerability Index, CalEnviroScreen, DWR Mapping Tools (DAC and Economically Distressed Areas [EDAs]), and FEMA’s National Risk Index for Natural Hazards. The California Office of Environmental Health Hazard Assessment (OEHHA) CalEnviroScreen tool applies a formula to generate a combined ranking score that considers 21 indicators for each census tract that cover pollution indicators, such as diesel emissions and concentrations of toxic clean-up sites and population indicators, such as poverty and unemployment rates. Census tracts with CalEnviroScreen rankings between 75 and 100 percent (i.e., a combined score in the top 25 percent of all census tracts in the State) are considered to be DACs. One of the population indicators for the CalEnviroScreen identifies housing burdened communities. Housingburdened low-income households are households that are both low income and highly burdened by housing costs. California has very high housing costs relative to the rest of the country, which can make it hard for households to afford housing (OEHHA 2022). Households with lower incomes may spend a larger proportion of their income on housing and may suffer from housing-inducted poverty (OEHHA 2022).

Housing affordability is an important determinant of health and well-being. Low-income households with high housing costs may suffer adverse health impacts. These households are also more likely to be adversely affected during a hazard event and less likely to recover as quickly as other communities.

There are numerous communities within Stanislaus County with a higher housing burden; these communities are concentrated in the cities of Modesto, Ceres, Turlock, and Patterson, which is similar to the socially vulnerable populations identified by SoVI. Several of the census tracts in these cities rank 862
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between 75 and 100 percent and are considered DACs; they also consist of low income and severely burdened by housing costs. Some of these communities housing burden is also higher than 90 percent of the rest of California. The County can use information about these communities to conduct targeted outreach and engage community members to consider what other hazards and mitigation strategies or programs should be considered to meet community needs. The County can also engage these communities to proactively prioritize hazard mitigation projects that benefit DACs.

Figure 4-3 Social Vulnerability in Stanislaus County based on the SoVI, by Census Tracts 863
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Development Trends
The areas located in the Sphere of Influence (SOI) for each incorporated jurisdiction are areas each City plans to grow into and potentially slated for future development. Understanding the potential hazard exposure in each area can help to mitigate the impacts of events before development occurs in those areas.

Development trends since the previous 2017 LHMP update are also addressed. These growth and development trends are assessed in the future development trends subsection of the vulnerability assessment, each annex, and broadly summarized below. In general, most residential development has occurred or is proposed within the city limits of each jurisdiction.

During this plan update process a parcel analysis was also conducted using the SOI areas for each incorporated jurisdiction and overlaid with available hazard risk layers to determine where future development may be at risk of natural hazard events. The results of the analysis have been integrated into the applicable hazard sections: dam, flood, wildfire and landslide. Table 4-10 is the summary of the SOI total exposure by jurisdiction.

Table 4-10 Total Exposure Summary by Jurisdiction Sphere of Influence Areas Jurisdiction Improved
Parcel Count Improved Value Estimated Content Value Total Value Ceres 1,974 $268,710,296 $200,638,561 $469,348,857
Hughson 76 $19,505,347 $18,760,196 $38,265,543
Modesto 6,691 $1,673,437,332 $1,885,783,247 $3,559,220,579 Newman 4 $705,813 $705,813 $1,411,626
Oakdale 51 $12,457,109 $6,404,678 $18,861,787
Riverbank 65 $11,209,681 $8,512,805 $19,722,486
Turlock 656 $122,502,912 $105,060,814 $227,563,726
Waterford 82 $15,139,178 $14,810,922 $29,950,100
Total 9,599 $2,123,667,668 $2,240,677,035 $4,364,344,703 • City of Ceres – According to the City’s 2014 – 2023 General Plan Housing Element, the Stanislaus Council of Governments (StanCOG) allocated 2,571 housing units to the City for the period 2014 to 2023. The time frame for this Regional Housing Needs Allocation (RHNA) process is January 1, 2014, through September 30, 2023, (a nine-year planning period), equivalent to a yearly need of approximately 264 housing units for the 9 -year time period. There are 168 single-family units and 44 multi-family units in projects that are anticipated to be built in during the 2014-2023 Housing Element timeframe. The City of Ceres has also been working on other master and specific plans, including Eastgate Revised Master Plan (revised in 2004), Mitchell Road Corridor Specific Plan (adopted in 1995, which establishes comprehensive guidance and regulations for the development of approximately 450 acres located along a 2.5 mile stretch of Mitchell Road between Highway 99 and the Tuolumne River within the City of Ceres), West Landing Specific Plan (which encompasses 960 acres of developed, underdeveloped and agricultural land that was annexed and is now part of the western area of the City limits, bounded by Whitmore Avenue to the north, Service Road to the south, Ustick Road to the west and the Union Pacific rail line to the east), and the Whitmore Ranch Specific Plan (that was annexed into the City of Ceres, and includes approximately 94 acres that is bounded by Whitmore Avenue on the north, Moore Road on the west, and the east side of La Rosa Elementary School on the east). • City of Hughson – On June 18, 2014, StanCOG adopted its RHNA plan for the January 1, 2014, through September 20, 2023, projection period. Hughson’s RHNA share includes 26 units for the extremely low-income category, 27 for very low, 34 for low income, 38 for moderate income, and 93 above moderate-income units for this RHNA period – a total of 218 housing units. The City also has an ongoing Parkwood Subdivision Project that includes 299 single-family residential lots with one singlefamily home per lot. This site is approximately 56.04 acres and is located at the southeastern corner of the Santa Fe Avenue and Hatch Road intersection in the City. • City of Modesto – According to the City’s 2015 – 2023 Housing Element, the City of Modesto’s RHNA is 6,361 units. Based on the Opportunity Sites webpage published by the City’s Planning Division, as of August 2, 2017, the City has 1,192 acre of sites with available infrastructure, 175 acres within close proximity to infrastructure, and 704 acres of sites that would require infrastructure extensions. The City’s Planning Division also has various ongoing specific plans designated for various development 864
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projects, such as Carver Bangs, Empire North and Fairview Village. In addition, to ensure that Modesto’s growth is handled in a fiscally responsible manner, the Modesto City Council adopted an Urban Growth Policy on March 25, 1974. One goal of the 1974 Urban Growth Policy was to maintain a three- to five-year supply of vacant residential land for future development. The most recent urban growth review report goes back to 2015.
• City of Newman – According to the City’s 2030 Housing Element, the City of Newman’s RHNA is 778 units. The City also has a Highway 33 Specific Plan that is ongoing. • City of Oakdale – to the City’s 2015 – 2023 Housing Element, the City of Oakdale’s RHNA is 1,247 units. The City’s Planning Division has various ongoing specific plans designated for various development projects, such as Burchell Hill, Bridle Ridge and East F Street. • City of Patterson – The City’s updated Housing Element is still in the process. According to the City’s Community Development webpage, the City has various businesses pending, as well as various housing projects, including apartment development projects. • City of Riverbank – According to the City’s 2015 – 2023 Housing Element, the City of Riverbank’s RHNA is 1,247 units. According to the City’s Planning Division’s Current Planning Projects documentation, the City’s Planning Division has various ongoing development projects, such as Bruin Heights Subdivision, Diamond Bar East Subdivision and Countryside 1 and 2 Subdivision. • City of Turlock – According to the City’s 2015 – 2023 Housing Element, the City of Turlock’s RHNA is 3,618 units. The City’s Planning Division also has various ongoing specific plans designated for various development projects, such as the Morgan Ranch Mater Plan and the North Turlock Master Plan. The City’s Planning & Land Use Permitting division also keeps track of active ongoing residential and commercial & industrial projects.
• City of Waterford – According to the City’s 2015 – 2023 Housing Element, the City of Waterford’s RHNA is 882 units.

4.3 Hazard Analysis and Risk Summary
Requirement §201.6(c)(2)(i):
[The risk assessment shall include a] description of the type, location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

4.3.1 Agricultural Pests and Disease
Hazard/Problem Description
Located in the Central San Joaquin Valley, Stanislaus County’s farming and agricultural industry is ranked as the top agriculture-producing County in California and the country. Agriculture is the dominant land use in Stanislaus County, accounting for 86% of all land, or approximately 832,453 acres out of the 970,168 acres inventoried in the County (Stanislas County 2016). According to the Stanislaus County Department of Agriculture, agriculture grossed more than $2.9 billion dollars in 2020. Top commodities in 2020 included almonds, milk, chickens, and cattle & calves (see table below).

Table 4-11 Top 10 Commodities in Stanislaus County in 2020 Rank Crop 2020 Value Top 10 Share
1 Almonds $1,123,961,000 32%
2 Milk $736,644,000 21%
3 Chickens $342,099,000 10%
4 Cattle & Calves $201,783,000 6%
5 Nursery, Fruit & Nut Trees & Vines $163,123,000 5%
6 Walnuts $103,040,000 3%
7 Silage $99,498,000 3%
8 Almond Pollination $88,800,000 3%
9 Turkeys $54,117,000 2%
10 Tomatoes $37,991,000 1%
Top 10 Total $2,951,056,000
Source: 2020 Report on Agriculture
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Agricultural pests and pathogens (insects, fungi, bacteria, viruses and invasive plants) cause injury or severe destruction to crops or livestock. From exotic fruit flies to noxious weeds, California’s agriculture can be impacted by a wide variety of invasive pests and pathogens. These pests pose significant threats to the state’s agricultural crops, farm workers, economy, food supply and native habitat. They can also result in increases in food prices for consumers. The number of invasive pests and pathogens newly detected in California and the rest of the United States has increased at alarming rates in recent years, and that trend is projected to continue into the future. Insect pests and diseases, such as bark beetles and Sudden Oak Death in trees can also destroy forests and oak woodland habitat located along the eastern and western perimeters of Stanislaus County, which can in turn increase the fuel load and lead to greater fire risk.

Agricultural disasters could also occur due to severe weather events, such as extreme heat, freeze cycles, and heavy rainfall and these hazards are covered under Subsections 4.3.10 through 4.3.14. Drought events are covered under Subsection 4.3.5.

Agricultural pest and disease management programs are managed at the state level in California. The California Food and Agricultural Code mandates pest prevention programs to prevent the introduction and spread of pests in the state, funds such programs, and directs administration of the programs to the local municipalities. These include the Pest Exclusion Program, Pest Detection Program, Pierce’s Disease Control Program, and Federal Phytosanitary Certificate Program. Target pests addressed by each program are listed in Table 4-12, but also include dairy, livestock, and poultry pests and diseases, such as Mycobacterium bovis and pathogenic avian influenzas. Animal agriculture, such as dairy farms also result in copious amounts of manure, which contain zoonotic pathogens, which are viruses, bacteria, and parasites of animal origin that cause disease in humans.

Table 4-12 Target Pests in Stanislaus County
Target Pest Crops Affected Traps Deployed
Melon Fruit Fly Apple, bean, cantaloupe, cucumber, grape, orange, peach, pear, tomato & watermelon 315
Asian Citrus Psyllid Citrus 591
Glassy-Winged
Sharpshooter Almond, Citrus, Grape & Peach 1,926
Apple Maggot Pome & Stone Fruit 15
Gypsy Moth Most Trees 204
Mexican Fruit Fly Apple, Apricot, Citrus, Nectarine, Pear, Plume, Peach & Pomegranate 224
Japanese Beetle Roses & Turf 204
European Corn Borer Corn, Green Bean, Oat, Potato & Rhubarb 8 Light Brown Apple Moth Alfalfa, Almond, Apple, Berries, Broccoli, Citrus, Corn, Grapes, Stone Fruit, & Tomato 433
Mediterranean Fruit Fly
Almond, Apple, Apricot, Citrus, Fig, Grape, Nectarine,
Olive, Peach, Pear, Plum, Pomegranate, Tomato, &
Walnut 433
Oriental Fruit Fly Apple, Citrus, Cucumber, Fig, Grape, Pear, Pomegranate, Stone Fruit, Tomato & Walnut 433
Red Imported Fire Ant Agricultural and residential settings 81 European Grapevine
Moth Grapes & Spurge Laurel 297
Vine Mealybug Grapes 22
Khapra Beetle All grain & grain-products 107
Source: 2020 Report on Agriculture
Geographic Area
Extensive – According to the 2017 Census for Agriculture, Stanislaus County contains 722,546 acres of land in farms. Cropland accounts for 56% of agricultural land, while pastureland accounts for 36%. There are approximately 3,621 farms (as of 2017) in the County. Most of these important farmlands are located within the County’s unincorporated area and are currently zoned for agricultural use. Figure 4-4 illustrates the geographic extent of the important farmlands across the County. 866
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Figure 4-4 Stanislaus County Important Farmland
Extent (Magnitude/Severity)
Limited – Different pests can impact different crops in different ways; while there is no scale to define the extent of an infestation, a pest could have a major economic impact on the value of infested crops.

Another large factor that may influence crop yield is the spread of invasive plants, which may compete with crops for resources and in some cases also introduce pests. According to California Invasive Plant Council (Cal-IPC), invasive plants cost California $82 million every year in control, monitoring and outreach; estimated actual impacts can reach into the billions. Based on the USDA’s Risk Management Agency (RMA) Crop Indemnity Reports, between 2007 and 2018 (no losses were reported in 2019 or 2020), there 867
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were 1,755 acres lost due to plant disease and insects and $792,604 indemnity payments made. This results in an annualized loss of $72,055 due to agricultural pests.

Past Occurrences
Based on information from the USDA, Stanislaus County received several USDA disaster declarations since 1950 (see Table 4-3 above). All the declarations were associated with flood, drought or severe weather events, and most recently, the COVID-19 pandemic. None were related to agricultural disease.

Probability of Future Occurrences
Likely – While probability of future occurrence is usually calculated based on past impacts, different pests have different recidivism rates across the County. Based on past occurrences, pests and invasive species will continue to present a constant threat to the County and its jurisdictions. These events are therefore expected to occur on an annual basis or have a 100% chance of occurring each year due to economic impacts and number of control measures (e.g., traps) deployed annually.

Climate Change Considerations
California’s Fourth Climate Change Assessment (2018) notes that “climate change impacts terrestrial ecosystems and wildlife in multiple ways, including invasion by exotic species, prevalence of wildlife disease, and loss of native habitats.” Changing climate conditions can impact viable living areas of species and cause migration; shift the spread of pests and disease northward by changing habitat temperatures and making previously undesirable habitats welcoming for new species and lengthen habitable seasons (CNRA 2018a). Longer growing seasons may also allow agricultural pests to persist longer, which can increase the severity of infestations on agricultural operations. Further, weather events have become more numerous and more severe. Changes in weather patterns can also have dramatic impacts on the ecosystem, including agriculture systems, and more severe impacts can be expected into the future.

Vulnerability Assessment
Agricultural losses occur on an annual basis and are usually associated with severe weather events, including heavy rains, floods, hail, freeze, and drought. The California SHMP attributes most of the agricultural disasters statewide to drought, freeze, and also insect infestations. Other agricultural hazards include fires, crop and livestock disease, noxious weeds, and contamination of animal food and water supplies.

General Property
Infestation of agriculture pests could result in negative consequences associated with decreased crop yields, potential destroying whole fields with farmland property. Between 2015 and 2018, the USDA’s RMA paid no indemnities due to damage from insects but paid $22,900 in indemnities due to damage from crop disease.

People
A widespread infestation of livestock and crops could result in severe consequences to the economic base of the County and its communities employed by the agriculture industry. According to the USDA 2017 Census of Agriculture, Stanislaus County has 2,337 farms, which is a -6% change from the previous census in 2012. While agricultural production in the County can enhance the economy and improve human health and ensure stable food prices in California and the U.S., certain habitats established for irrigation and agricultural output can also threaten human health by increasing the risk of vector-borne diseases (e.g. mosquitos, etc.). Agricultural pests and disease or significant crop loses can also impact communities if they result in limited food supplies and rises in food prices. Widespread crop losses due to contamination issues (foreign agents, biological disease) could also decrease the public’s confidence in food safety. Rural communities, residing closest to these agricultural operations may also be most vulnerable to these diseases, as livestock pathogens are capable of infecting host species, which may include wildlife and human.

Stanislaus County’s General Plan Agricultural Element contains Policy 1.10 designed to protect agricultural operations from conflicts with non-agricultural uses by requiring buffers between proposed non-agricultural uses and adjacent agricultural operations (Stanislaus County 2017). The Agricultural Element also contains 868
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Buffer and Setback Guidelines that provide further direction on how to protect the long-term health of local agriculture resulting from new or expanding uses in or adjacent to the General Agricultural zoning district.

Buffers consist of a physical separation, such as a topographic feature, stand of trees, waterway, landscaped berm, or a similar feature that serves as a barrier between agricultural uses and the people in non-agricultural areas. Buffers lessen the impacts of surrounding development by minimizing conflicts between agricultural and non-agricultural uses.

Jobs could be negatively impacted during an agriculture emergency; jobs tangentially tied to the agriculture industry could also be affected. According to “The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment”, rising temperatures and drought conditions due to climate change could also lead to increases in the occurrence and transport of pathogens in agricultural environments, which will increase the risk of food contamination and direct human exposure to pathogens and toxins (SGCRP 2016). In turn, this will increase health risks and require greater vigilance in food safety practices and regulation.

Disease can also exacerbate the impacts from other natural hazards. An example of this is adverse weather. Dead branches can be broken by high winds, and there are reports of these branches falling and causing harm to people.

Social Vulnerability
Based on the SoVI data presented and discussed in Subsection 4.2.1, the areas with the highest level of social vulnerability are in the central, southern and southwestern portions of the County, including some of the incorporated jurisdictions such as the Cities of Modesto, Ceres, and Turlock. These communities as well as those working in the agricultural sector would likely be impacted by the effects of agricultural hazards.

Government Services
Few consequences are anticipated related to agricultural pests and related crop loss on first responders, the continuity of operations, delivery of services. However, if significant crop losses are associated with perceived poor management of adhering to health and safety requirements, it could lead to a loss in confidence in state governance. When coupled with rises in food prices, this could lead to greater economic impacts on the County, and those most vulnerable to food price increases.

Critical Facilities
Critical facilities assessed in this plan would not be directly impacted by agricultural pests or diseases; however, the food and agriculture industry is considered critical infrastructure in Stanislaus County and California. Impacts to this infrastructure, such as farms, diary operations, and processing facilities would have debilitating effects of food security, the economy, and public health and safety. Stanislaus County farms and ranches, and the associated food processing facilities would be directly impacted economically by long-term disruptions in the food supply associated with crop losses due to agricultural pests and disease.

Economy
According to the University of California’s Center for Invasive Species Research, it has been estimated in California alone that invasive pests cost the State at least $3 billion per year. Nationally, it is estimated that invasive species cost the U.S. $138 billion per year. Economic impacts include both prevention, response and recovery costs. Given the contribution of agriculture to the local economy, pest impacts could be significant. The value of agricultural commodities noted at the beginning of this hazard profile is $2,526,335,000. Based on that a hypothetical loss of 5% to due to agricultural pest or disease would equate to approximately $126 million in total economic losses.

Historic, Cultural and Natural Resources
Invasive species typically harm native species through predation, habitat degradation and competition for shared resources; they can outcompete native species out of natural habitats and are a leading cause of population decline and extinction in animals. Tree mortality raises the wildfire threat in healthy forests, increasing the vulnerability, strength, speed and destruction of fires in the area. Significant crop failures can also result in impacts on the environment if they result in contamination or the need for groundwater or surface water monitoring.
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Future Development
Most likely, good development practices and the ongoing implementation of the buffer policies included in the County’s Agricultural Element would not have an impact on Stanislaus County’s vulnerability to agricultural pests, plant diseases, or tree mortality.

Risk Summary
• Stanislaus County’s farming and agricultural industry is ranked as the top agriculture-producing county in California and the country.
• Agriculture is the dominant land use in Stanislaus County, accounting for 86% of all land, or approximately 832,453 acres out of the 970,168 acres inventoried in the County. • Invasive plants cost California $82 million every year in control, monitoring and outreach and over a 11-year period there were 1,755 acres lost due to plant disease and insects and $792,604 indemnity payments made that resulted in an annualized loss of $72,055 due to agricultural pests. • Based on USDA disaster declarations since 1950, none were related to agricultural pests or disease. • Changes in weather patterns can have dramatic impacts on the ecosystem, including agriculture systems, and more severe impacts associated with agricultural pests and disease can be expected into the future.
• Policies in the Stanislaus County’s General Plan Agricultural Element require buffers between proposed non-agricultural uses and adjacent agricultural operations to minimize incompatible use conflicts and to protect the long-term health of local agriculture resulting from new or expanding uses in or adjacent to the General Agricultural zoning district.
• Changing climate conditions can shift the spread of pests and disease northward by changing habitat temperatures and making previously undesirable habitats welcoming for new species through longer growing seasons. This may increase the severity of pest infestations on agricultural operations. • Related hazards – Drought
Table 4-13 Hazard Risk Summary by Jurisdiction – Agricultural Pests and Disease Jurisdiction Geographic
Area
Probability
of Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Extensive Likely Limited Low No
City of Ceres Extensive Likely Negligible Low No
City of Hughson Extensive Likely Negligible Low No
City of Modesto Extensive Likely Negligible Low No
City of Newman Extensive Likely Negligible Low No
City of Oakdale Extensive Likely Negligible Low No
City of Patterson Extensive Likely Negligible Low No
City of Riverbank Extensive Likely Negligible Low No
City of Turlock Extensive Likely Negligible Low No
City of Waterford Extensive Likely Negligible Low No
County Office of Education Extensive Likely Negligible Low No

4.3.2 Aquatic Invasive Species (AIS)
Hazard/Problem Description
Aquatic Invasive Species (AIS) is a non-native aquatic species that invade ecosystems beyond their natural, historic range. They are spread either intentionally; someone dumping their aquarium contents into a lake or unintentional by way of ships, fishing, hunting and boating, to name a few. AIS might also be called exotics, nonindigenous or non-native. They are a growing problem due primarily to increased global trade (California State Parks 2021).
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Many AIS arrive in the United States by being accidentally transported here in the ballast water of oceangoing ships – and then they move from lake to lake by hitching rides with unsuspecting boaters and anglers. A whole population of invasive plants or mussels can start from a tiny fragment of a leaf or a microscopic larva, so it is easy for these invaders to reach new water bodies by clinging to our gear. (Izaak Walton League of America 2021)
AIS—plants, quagga, and zebra mussels—are invading California’s Sacramento-San Joaquin Delta and reservoirs and lakes. These pests can increase dramatically under the right conditions, displacing native species, clogging waterways, and creating hazardous conditions for navigation and recreation. Once introduced, they are nearly impossible to eradicate. Egeria densa, water hyacinth, and quagga and zebra mussels are some of the nuisance species that can be accidentally transported by recreational boaters when caught in propellers or intakes or attached to hulls. Controlling these AIS is a multi-million-dollar problem in California. (USFWS 2021)
According to University of California Agricultural and Natural Resources (UCANR)’ research, symbolic AIS that have been impacting the Central Valley and the San Francisco Bay and Delta region include Giant reed (Arudno donax), American bullfrog (Lithobates catesbeianus), Nutria (Myocastor coypus) and Quagga & zebra mussels (Driessena bugensis and Driessena polymorpha). Key AIS in Stanislaus County are described below.

Giant Reed (Arudno donax)
Giant Reed (Arundo donax) is an extremely fast-growing perennial grass that can reach heights of over 20 feet. It is often found in riparian and wetland ecosystems, sand dunes, and disturbed areas. Arundo is native to the Greater Mediterranean Area and was introduced to California for erosion control. It outcompetes important stream-side species (such as willows) for water and habitat, leading to altered ecosystem function and less shade along riparian ecosystems. Its stems and leaves are not used as habitat or food by native animals and contain harmful chemicals that make it unappealing to insects and grazing animals.

American Bullfrog (Lithobates catesbeianus)
American Bullfrogs (Lithobates catesbeianus) are a large species of frog native to Central and Eastern United States. They prefer shallow, slow-moving, or stagnant freshwater pools and ponds but have been found in the shorelines of lakes and rivers. They have been known to not only outcompete native species for food and habitat but have been documented as predators of native California birds, fish, reptiles, amphibians, and invertebrates. Additionally, they are linked to the introduction of the deadly chytrid fungus, a disease known to have caused population declines and the extinction of amphibian populations around the world.

Nutria (Myocastor coypus)
Nutria (Myocastor coypus) is a large, aquatic rodent reaching 1.64 feet in length and weighing up to 22 lbs.

They were first found in California in 2017 and have since been confirmed in several counties including San Joaquin, Stanislaus, Merced, Fresno, Mariposa, and Tuolumne. Nutria are exceptional herbivores that consume large amounts of wetland vegetation, up to 25% of their body weight daily. In regions where they have been introduced, they have devastated marsh and wetland habitats through their consumption and burrowing and in some cases, converting vegetated marsh lands to unvegetated open water habitats.

Quagga and Zebra mussels (Driessena bugensis and Driessena polymorpha) The quagga mussel (Driessena bugensis) and zebra mussel (Driessena polymorpha), known together as Eurasian mussels, are originally from Ukraine and were first detected in California in 2007 and 2008 and have since spread to canals, rivers, and lakes around the state. Although they measure under 2 inches long, they can cause major ecological harm by modifying aquatic habitats and pose a threat to the environment and to California's water supply. They reproduce rapidly and in high densities, competing for space with native species. They filter phytoplankton out of huge volumes of water which can change the physical and biological properties of an ecosystem. Eurasian mussels also cause significant economic harm by damaging boat engines, clogging pipes, covering infrastructure such as docks, dam gates, and irrigation channels, and reducing the recreational and economic value of lakes. 871
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Geographic Area
Limited – The UCANR California Aquatic Invasive Species Site maintains a web-based GIS map that shows the distribution of AIS in California. According to their GIS data and online maps, various AIS grow in Stanislaus County and the Central Valley in general. Within the County, AIS tend to grow and develop the major waterways, for example, the Stanislaus River, Dry Creek, Tuolumne River, and San Joaquin River. However, as AIS only tend to grow along and impact major waterways instead of the County’s land area, the overall geographic area that AIS impact is then limited.

Figure 4-5 below shows the AIS distribution in Stanislaus County. The dots with different colors on the map represent different types of AIS, including snails, mussels, and clams; plant and algae; mammals; herps; flatworms and flukes; fishes; crustaceans; and colonial invertebrates that occur in the County.

Figure 4-5 AIS Distribution in Stanislaus County
Source: UCANR 2021
Extent (Magnitude/Severity)
Negligible – Invasive species infest, disrupt, and degrade the ecology of native habitats, and cause negative economic impacts. AIS weaken fisheries, reduce biodiversity, heighten levels of toxins throughout the water and food chain, and outcompete native species, resulting in dramatic overgrowth in many cases.

They also cause harm to human health and negatively impact the economies of communities that rely on tourism and outdoor recreation. Personal property values and tax revenues for local governments can decrease when AIS invade recreational waterbodies, but they rarely directly impact infrastructure. The cumulative impacts of several invasive species in an area can degrade natural resources and diminish human enjoyment.

Invasive species are easily spread through connected waterways in Stanislaus County, and most are unintentionally transported by trailered recreational boats and on fishing gear and equipment. Once introduced, AIS take root in new environments very quickly. They typically do not have natural predators, and it is difficult for human management to eradicate an infestation. Clean-ups are beneficial, but there are rarely 100% effective eradication efforts once an invasive species is established in a waterbody. (Adirondack Council 2021). The severity of AIS in Stanislaus County mainly impacts environmental resources, which is evident in the impacts from the semi-aquatic rodent Nutria, but the severity of impacts on property is negligible given the state and county capabilities already in place. 872
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Past Occurrences
There have been no federal or state disaster declarations from AIS. The HMPC have noted past occurrences due to various AIS, and Nutria in the County. As mentioned above, AIS has been invading the environment and causing problems in Stanislaus County, the nearby counties, and the entire State of California. The San Francisco Bay Delta, which covers the very northern portion of Stanislaus County near the San Joaquin River has more identified nonindigenous species present than any other estuary in North America (California SHMP 2018).

Probability of Future Occurrences
Likely – AIS is expected to continue being a hazard to Stanislaus County and California, given its already established presence and the fact that AIS can be easily introduced to California waters from throughout the world as regional and international trading and transporting grows and develops, as well as unintentional behavior such as dumping unwanted aquarium contents into a lake.

The State has several programs in place to prevent the introduction of AIS. The Ballast Water Management for Control of Nonindigenous Species Act of 1999, as amended and reauthorized by the Marine Invasive Species Act of 2003, targets at preventing the introduction of nonindigenous species via vessel vectors (ballast water and biofouling). The Marine Invasive Species Act applies to all U.S. and foreign vessels that are 300 gross registered tons or more that arrive at California ports. Under the Marine Invasive Species Act, vessels are required to submit a Ballast Water Management Report for each arrival at a California port or place and an Annual Vessel Reporting Form that requests information on vessel biofouling management practices and the use of ballast water treatment technologies. (California SHMP 2018). These programs are the State’s capabilities that aim to inhibit the introduction of AIS, which decrease AIS’ future occurrences.

The CDFW also administers the State’s Invasive Species Program. The goal of the Invasive Species Program is to prevent, detect, and respond to species introductions when they occur and prevent the spread of species that have become established. CDFW is responsible for the State’s Dreissenid Mussel Prevention Program. In 2016, CDFW adopted new regulations to prevent the spread of quagga and zebra mussels in California freshwater environments. The new regulations include provisions requiring vulnerability assessments, prevention programs, monitoring, and management of state reservoirs. (California SHMP 2018). These existing plans also minimize the probability of future occurrences of AIS in Stanislaus County. Although various capabilities are place at both the state and county level, AIS events are expected to continue to occur once or more per year and have up to a 100% chance of probability in any given year.

Climate Change Considerations
Climate change is expected to result in warmer water temperatures, a shorter duration of ice cover, altered streamflow patterns, increased salinization, and increased demand for water storage and conveyance structures. These changes will alter the pathways by which non-native species enter aquatic systems by expanding fish-culture facilities and water gardens to new areas and by facilitating the spread of species during floods. Climate change will influence the likelihood of new species becoming established by eliminating cold temperatures or winter hypoxia that currently prevent survival and by increasing the construction of reservoirs that serve as hotspots for invasive species. Climate change will also modify the ecological impacts of invasive species by enhancing their competitive and predatory effects on native species and by increasing the virulence of some diseases. As a result, new prevention and control strategies such as barrier construction or removal efforts may be needed to control AIS that currently have only moderate effects or that are limited by seasonally unfavorable conditions. Although most researchers focus on how climate change will increase the number and severity of invasions, some cold-water AIS may be unable to persist under the new climate conditions. Figure 4-6 shows the impacts of climate change on aquatic systems and the interactions with invasive species. 873
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Figure 4-6 Impacts of climate change on aquatic systems & the interactions with invasive species
Source: Rahel et al. 2008, 521-33
Furthermore, according to Canada’s Invasive Species Centre’s findings, changes to climate can create favorable conditions for the increased spread of invasives, causing “sleeper species” to awaken. Sleeper species are non-native species already present in an ecosystem that have the potential to be invasive but are limited by factors such as climate or other species. Figure 4-7 shows that is species that were limited by unfavorable climate can awaken once climate becomes favorable, which could lead to the species growth and invasion of this species as well as the need for additional controls. (Invasive Species Centre 2021)
Figure 4-7 Sleeper species abundance vs. time vs. cost of control Source: Invasive Species Centre 2021
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Vulnerability Assessment
General Property
AIS often does not pose any direct threat on the general property. Meanwhile, aquatic invasive vegetation damages marina structures and boat launches. Dense mats of aquatic weeds create hazards for boaters, anglers, and swimmers. (California State Parks 2021)
People
The most significant impact related to people from AIS is its effects on human recreation. As mentioned in the General Property subsection above, boaters, anglers, and swimmers face potential hazards imposed by dense mats of aquatic weeds. Sharp mussel shells can leave beach areas unsuitable for recreation.

Non-native aquatic invasive vegetation obstructs waterways, entangles boat propellers, overheats motors, and can completely disable vessels. These quick-growing plants can hide dangerous obstructions and cause hull damage and accidents. Species like Tiny Dreissenid mussels can ruin boat hulls and engines (California State Parks 2021). Moreover, AIS can result in negative consequences on fishing and make water sports like kayaking more difficult. With AIS competing and preying on native species, important native fish species’ population can also reduce. This in turn can make an infested lake harder to fish, which can impact the business of resorts, restaurants, and guiding services (Hubbard SWCD 2021).

Moreover, Invasive species can cause impacts ranging from psychological effects, phobias, discomfort, and nuisance to allergies, poisoning, disease, and even death. According to the U.S. Federal Aquatic Nuisance Species Task Force’s, the effect of AIS on public health extends beyond the immediate effects of disease and parasites as chemicals used to control invasive species can pollute soil and water. Other AIS, such as invasive mussels, may also increase human and wildlife exposure to organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) as these toxins accumulate in their tissues and are passed up the food chain.

Government Services
Public confidence may be hindered if warnings and alerts related to AIS removal and prevention are not communicated effectively. The government’s ability to respond and recover may be questioned if planning, response, and recovery is not timely and effective, particularly in areas where AIS significantly impacts the economy, including recreation, tourism, shipping, transportation, and other related industries.

Damage to public water and sewer systems, water transportation networks, and flood control facilities can hinder the ability of the government to deliver services. Drinking water and wastewater treatment facilities may be temporarily out of operation due to AIS-related issues. Responders employed by AIS-control-related agencies such as CDFW will be expected to respond and mitigate AIS outbreaks. Otherwise, the AIS’ impacts on responders would resemble its impacts on the general population.

Critical Facilities
AIS can significantly damage critical facilities and infrastructure. Thick mats of non-native aquatic invasive vegetation can quickly grow around and block water intakes for municipal water supply and agricultural irrigation. Dreissenid mussels can invade and grow on or inside of water supply and irrigation equipment, causing the pumps to work harder and/or eventually break down (California State Parks 2021).

The invasive species Advisory Committee under the U.S. Department of the Interior summarized several AIS impacts on infrastructure. Nutria negatively impact infrastructure in two ways: herbivory that leads to habitat destruction and burrowing behavior. Nutria burrows can weaken flood control levees that protect low-lying areas as well as roadbeds, stream banks, dams, and dikes under heavy weight. Giant reed chokes riversides and stream channels, crowds out native plants, interferes with flood control, and increases fire potential. The long, fibrous, interconnecting root mats of giant reed form a framework for debris dams behind bridges, culverts, and other structures that lead to damage. Dreissenid mussels also attach to locks, the faces, and interiors of dams and canal systems, greatly impacting operation and maintenance costs.

Economy
AIS impacts can cause economic loss in the tourism and recreation industry and the shipping and transportation industries. AIS also require control and inspection programs that require funding to prevent and remove AIS in waterways. AIS can reduce important native fish species’ population and make fishing 875
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harder, impacting resorts, restaurants, and guiding services. AIS can also impact human recreation, including waters sport like kayaking or boating, as well as swimming. Beaches can be closed due to AIS.

In California’s freshwater lakes, rivers, and reservoirs, zebra and quagga mussel infestations pose a significant threat to the State’s complex water conveyance system. As of 2016, more than $24 million has been spent on the control and management of these species. Water hyacinth, an invasive aquatic plant, has clogged the waterways of the Delta. In 2014, shipping traffic to the Port of Stockton was restricted to daylight hours due to high densities of hyacinth in waterways. The Port spent $200,000 to mechanically remove the plant. Meanwhile, the shipping industry lost an estimated $300,000 due to delays in cargo operations. (California SHMP 2018)
Historic, Cultural and Natural Resources
AIS’ impacts on historical and cultural resources would be similar to its impact on general property. Although the direct impact would be minimal, property values can decrease when AIS invade recreational waterbodies.

As far as AIS’ impacts on natural resources, U.S. Federal Aquatic Nuisance Species Task Force states that introduced species are a greater threat to native biodiversity than pollution, harvest, and disease combined.

AIS cause severe and permanent damage to the habitats they invade by reducing the abundance of native species and altering ecosystem processes. AIS prey on other species, compete with native species for food and space, live on or in another organism (parasitism), or degrade or even destruct ecosystems and fish habitat via eroding or destroying vegetation for example. AIS can also introduce harmful pathogens and parasites. Moreover, AIS may alter ecosystem function by altering fire regimes, hydrology, nutrient cycling, and productivity (Government of Canada 2019; U.S. Federal Aquatic Nuisance Species Task Force 2021).

Giant reed, for example, can outcompete and completely suppress native vegetation once established.

Meanwhile, giant reed reduced habitat for wildlife, including the least Bell’s vireo, listed as a federal and state endangered bird species.

Future Development
Federal, state, and local efforts and programs are in place to remove AIS and mitigate its existing impacts, as well as prevent the introduction of new AIS. These programs include the Marine Invasive Species Act as well as CDFW’s Invasive Species Program and Dreissenid Mussel Prevention Program. Stanislaus County also implements the Invasive Species Program online under the County’s Department of Parks and Recreation, which includes a prevention program and guidebooks regarding zebra and quagga mussel and other invasive mussels. Given that AIS can be introduced to the County and the surrounding areas’ waters via various pathways, agencies are encouraged to promote the education and outreach efforts to raise the boaters, water transportation workers, and the general public’s awareness of AIS. Such efforts are critical in many aspects, such as minimizing the unintentional introduction of AIS, teaching people how to prevent the spread of AIS, and the timely reporting of potential AIS when observed.

Risk Summary
• AIS can be introduced and then spread via various pathways. For example, unintentional behavior such as dumping aquarium contents into a lake can trigger the introduction of AIS. • Several symbolic AIS already established in Stanislaus County and within the Central Valley include Giant reed, American bullfrog, Nutria and Quagga and zebra mussels. • Although various capabilities are place at both the state and county level in Stanislaus, AIS events are expected to continue to occur once or more per year and have up to a 100% probability of future occurrence.
• It is expected that AIS will continue causing damages to the County; climate change can introduce and even accelerate the spread of AIS.
• AIS can have various impacts on the environment and economy, by destructing the environment and natural resources as well as threatening economic development and damaging recreation and tourism industries.
• Related Hazards – Agricultural Pests and Disease, Drought, Flooding. 876
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Table 4-14 Hazard Risk Summary by Jurisdiction – Aquatic Invasive Species Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Limited Likely Negligible Low No
City of Ceres Limited Likely Negligible Low No
City of Hughson Extensive Likely Negligible Low No
City of Modesto Limited Likely Negligible Low No
City of Newman Limited Likely Negligible Low No
City of Oakdale Limited Likely Negligible Low No
City of Patterson Limited Likely Negligible Low No
City of Riverbank Limited Likely Negligible Low No
City of Turlock Limited Likely Negligible Low No
City of Waterford Limited Likely Negligible Low No
County Office of Education Limited Likely Negligible Low No

4.3.3 Cyber Attack
Hazard Problem/Definition
The 2018 California SHMP defines cyber attacks as “attempts by cyber criminals to attack a government, organization, or private party by damaging or disrupting a computer or computer network, or by or stealing data from a computer or computer network for malicious use.” Cyber attacks use malicious code to alter computer operations or data. The vulnerability of computer systems to attacks is a growing concern as people and institutions become more dependent upon networked technologies. The Federal Bureau of Investigation (FBI) reports that, “cyber intrusions are becoming more commonplace, more dangerous, and more sophisticated,” with implications for private- and public-sector networks. Cyber threats can take many forms, including:
• Phishing attacks – Phishing attacks are fraudulent communications that appear to come from legitimate sources. Phishing attacks typically come through email but may come through text messages as well. Phishing may also be considered a type of social engineering meant to exploit employees into paying fake invoices, providing passwords, or sending sensitive information. • Malware attacks – Malware is malicious code that may infect a computer system. Malware typically gains a foothold when a user visits an unsafe site, downloads untrusted software, or may be downloaded in conjunction with a phishing attack. Malware can remain undetected for years and spread across an entire network.
• Ransomware – Ransomware blocks access to a jurisdiction’s/agency’s/ business’ data by encrypting it. Perpetrators will ask for a ransom to provide the security key and decrypt the data, although many ransomware victims never get their data back even after paying the ransom. • Distributed Denial of Service (DDoS) attack – The most common type of cyber attack, a DDoS attack seeks to overwhelm a network and causes it to either be inaccessible or shut down. A DDoS typically uses other infected systems and internet connected devices to “request” information from a specific network or server that is not configured or powerful enough to handle the traffic. • Data breach – Hackers gaining access to large amounts of personal, sensitive, or confidential information has become increasingly common in recent years. In addition to networked systems, data breaches can occur due to the mishandling of external drives. • Critical Infrastructure/SCADA System attack – There have been recent critical infrastructure Supervisory Control and Data Acquisition (SCADA) system attacks aimed at taking down lifelines such as power plants and wastewater facilities. These attacks combine a form of phishing, malware, or other social engineering mechanisms to gain access to the system.

The 2018 California SHMP states: “Nationally, cybersecurity incidents such as financial fraud and government database breaches have increased from 5,503 in 2006 to 67,168 in 2014.” This is more than a 1200% increase in occurrence over just an 8-year period. As this trend continues and society and government functions become more technologically dependent, this hazard is of increasing concern. 877
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In one recent attempt to combat this threat, the State of California adopted Senate Bill (SB) 327 in September of 2018. This bill seeks to improve information privacy, specifically pertaining to connected devices. Existing laws in California require businesses to take all reasonable steps to dispose of customer records within their custody containing personal information and require businesses that own, license, or maintain personal information about a California resident to implement and maintain reasonable security procedures. SB 327, which went into effect January 1, 2020 further requires the manufacturer of connected devices to equip the device with a reasonable security feature to protect user information.

Geographic Area
Significant – Cyber attacks can and have occurred in every location regardless of geography, demographics, and security posture. Incidents may involve a single location or multiple geographic areas.

A disruption can have far-reaching effects beyond the location of the targeted system; disruptions that occur far outside the state can still impact people, businesses, and institutions within the County. All of Stanislaus County is potentially susceptible to cyber attacks, making the geographic extent significant.

Extent (Magnitude/Severity)
Not Applicable – There is no universally accepted scale to explain the severity of cyber attacks. The strength of a DDoS attack is often explained in terms of a data transmission rate. One of the largest DDoS disruptions ever, the October 21, 2016 Dyn attack, peaked at 1.2 terabytes per second and impacted some of the internet’s most popular sites that included Amazon, Netflix, PayPal, Twitter, and several news organizations.

Data breaches are often described in terms of the number of records or identities exposed. The Privacy Rights Clearinghouse, a nonprofit organization based in San Diego, maintains a database of data breaches in the United States. The largest data breach ever reported occurred in August 2013, when hackers gained access to all three billion Yahoo accounts. This incident is associated with California in the Privacy Rights Clearinghouse database as the company is headquartered in Sunnyvale, California. As the location of the headquarters of many large tech businesses and server farms, California as a state is potentially a greater target for cyber attacks. There have been many other instances in California where millions of records have been breached.

Ransomware attacks are typically described in terms of the amount of ransom requested, or by the amount of time and money spent to recover from the attack. One report from cybersecurity firm Emsisoft estimates the average successful ransomware attack costs $81 million and can take organizations 287 days to recover. Overall, the potential magnitude of a cyber attack can be seen as limited due to the lack of deaths and injuries, but the economic costs can be significant.

Past Occurrences
The cybersecurity firm Symantec reports there were a total of 1,209 data breaches worldwide in 2016.

While the number of breaches has remained relatively steady, the average number of identities stolen has increased to almost one million per incident. The report also found that one in every 131 emails contained malware, and the company’s software blocked an average of 229,000 web attacks every day.

California is by far the state with the highest number of data breaches. The Privacy Rights Clearinghouse database lists 1,338 data breaches against systems located in California, totaling over 5.7 billion impacted records; however, it is difficult to know how many of those affected Stanislaus County residents. Attacks happening outside of the State can also impact local businesses, personal identifiable information, and credit card information.

A 2017 study found ransomware payments over a two-year period totaled more than $16 million. Even if a victim is perfectly prepared with full offline data backups, recovery from a sophisticated ransomware attack typically costs far more than the demanded ransom. However, according to a 2016 study by Kaspersky Lab, roughly one in five ransomware victims who pay their attackers never recover their data.

Recent years have seen an increase in ransomware attacks, particularly against local government systems.

The City of Atlanta was hit by a major ransomware attack in 2018, recovery from which wound up costing a reported $2.6 million, significantly more than the $52,000 ransom demand. A similar attack against the 878
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City of Baltimore in 2019 affected the city government’s email, voicemail, property tax portal, water bill, and parking ticket payment systems, and delayed more than 1,000 pending home sales. In March 2019, Orange County, North Carolina was attacked with a ransomware virus, causing slowdowns and service problems at key public offices such as the Register of Deeds, the Sheriff’s Office, and County libraries. The attack impacted a variety of county services, including disrupting the County’s capability to process real estate closings, issue marriage licenses, process fees or permits, process housing vouchers, and verify tax bills.

Each of these past events are examples of the range of risks posed to county and municipal governments by various cyber attacks.

Reports of successful attacks against SCADA systems are less common. In February 2021, a hacker gained system access to a water treatment plant in Oldsmar, Florida and increased the levels of sodium hydroxide to dangerous levels; however, this change was immediately detected by plant staff and corrected.

A large, sophisticated malware attack, known as Olympic Destroyer, was launched against the 2018 Winter Olympics in PyeongChang, South Korea. The attack initially took down servers, email, Wi-Fi, and ticketing systems, which could have severely disrupted the games. Fortunately, the organizing committee had a robust cybersecurity group that was able to quickly restore most functions.

Probability of Future Occurrences
Likely – Small-scale cyber attacks such as DDoS attacks occur daily, but most have negligible impacts at the local or regional level. Data breaches are also extremely common, but again most have only minor impacts on government services.

Perhaps of greatest concern to Stanislaus County are ransomware attacks, which are becoming increasingly common. It is difficult to predict the odds of Stanislaus County being hit with a successful ransomware attack in any given year, but it is safe to say it is likely to be attacked in the coming years. The possibility of a larger disruption affecting systems within the County is a constant threat, but it is difficult to quantify the exact probability due to such highly variable factors as the type of attack and intent of the attacker, as such a specific probability of future occurrence was not quantified. Nonetheless, major attacks specifically targeting systems or infrastructure in the County cannot be ruled out.

Climate Change Considerations
There are no known effects of climate induced impacts on cyber attacks.

Vulnerability Assessment
The impact of a cyber attack can vary depending on the type of attack and the intent of the malicious actor.

Though a cyber disruption can have limited impacts within a system’s own operations, it may cause cascading impacts.

General Property
The vast majority of cyber attacks affect only data and computer systems and have minimal impact on general property.

People
Injuries or fatalities from cyber attacks would generally only be possible from a major cyber terrorist attack against critical infrastructure, such as potable water treatment and delivery systems. If such an event would occur it could indirectly impact the customers served by water utility. More likely impacts to the public are financial losses and an inability to access systems such as public websites and permitting sites. Indirect impacts could include interruptions to traffic-control systems or other infrastructure Data breaches and subsequent identify thefts can have huge impacts on the public. The Internet Crime Complaint Center (IC3) estimates that identity theft alone resulted in $2.7 billion in losses to businesses and $149 million in losses to individuals.

According to the Cyber & Infrastructure Security Agency (CISA), cyber risks to 9-1-1 systems can have “severe impacts, including loss of life or property; job disruption for affected network users; and financial costs for the misuse of data and subsequent resolution.” CISA compiled a recent list of attacks on 9-1-1 879
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systems including a DDoS in Arizona, unauthorized access with stolen credentials in Canada, a network outage in New York, and a ransomware attack in Baltimore.

Government Services
Cyber attacks have the potential to interfere with emergency response communication and activities. For example, many response agencies rely on IT technology to log incidents, notify response, and route responders to emergency events. 911 dispatch centers also rely on technology, which makes them vulnerable to cyber attacks. The County may be susceptible to cyber attacks if they rely on electronic backup of sensitive files that may impact their ability to continue to provide services during cyber attacks.

If personal and confidential data is not protected, this would impact the public’s confidence in the County.

The public may then be concerned on the security of electronic systems used for government services.

Critical Facilities and Infrastructure
While the vast majority of cyber attacks affect only data and computer systems, sophisticated attacks against utilities and infrastructure sites have occurred. Such attacks typically target the SCADA systems of critical infrastructure, which can potentially result in system failures on a scale equal with natural disasters.

Facilities and infrastructure, such as the electrical grid, could become unusable as a result of a cyber attack.

A cyber attack took down the power grid in Ukraine in 2015, leaving over 230,000 people without power.

Agencies that rely on electronic backup of critical files are also vulnerable.

The delivery of services can be impacted since governments rely to a great extent upon electronic delivery of services. Most agencies rely on server backups, electronic backups, and remote options for the continuity of operations or the continuity of government. Many departments in the participating jurisdictions have the option to move to a paper method including permitting, DMV services, payments to and from the County, and payroll. However, access to documents on the network, OneDrive access, and other operations that require collaboration across the County will be significantly impacted.

Loss of government servers due to a cyber attack could affect the ability of responders to do their jobs.

Cyber attacks can interfere with emergency response communications, access to mobile data terminals, and access to critical preplans and response documents. The delivery of services can be impacted since governments rely, to a great extent, upon electronic delivery of services. An attack could also raise questions regarding the security of using electronic systems for government services.

Economy
Economic impacts from a cyber attack can be debilitating. The cyber attack in 2018 that took down the City of Atlanta cost at least $2.5 million in contractor costs and an estimated $9.5 million additional funds to bring everything back online. The attack in Atlanta took “more than a third of the 424 software programs offline” and recovery lasted more than 6 months. A 2018 cyber attack on the Colorado Department of Transportation (CDOT) cost an estimated $1.5 million. None of these statistics take into account the economic losses to businesses and ongoing IT configuration to mitigate from a future cyber attack. Similar events may result in economic impacts in Stanislaus County.

Historic, Cultural, and Natural Resources
The vast majority of cyber incidents have little to no impact on historic, cultural or natural resources. A major cyber terrorism attack could potentially impact the environment by triggering a release of a hazardous materials, or by causing an accident involving hazardous materials by disrupting traffic-control devices.

Future Development
Changes in development have no impact to the threat, vulnerability, and consequences of a cyber attack.

Cyber attacks can and have targeted small and large jurisdictions, multi-billion-dollar companies, small mom-and-pop shops, and individual citizens. The decentralized nature of the internet and data centers means that the cyber threat is shared by all, regardless of new construction and changes in development.

Risk Summary
• The overall significance of cyber attacks in Stanislaus County is Medium. These incidents occur frequently, with California being the State with by far the most reported incidents. The possibility of an attack of any scale impacting the County is almost certain. 880
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• There have been 1,338 data breaches statewide over a 14-year period, averaging approximately 96 incidents per year, or up to eight incidents each month. • Nationwide the increase in cyber attacks has been dramatic year over year. As this trend continues it is safe to assume there is a threat to Stanislaus County. • Injuries and fatalities to people are unlikely, unless in a widescale attack that affected infrastructure and resulted in indirect impacts on communities. People may also be impacted financially. • The vast majority of attacks do not affect property.
• Economic impacts from a cyber attack can be debilitating, sometimes costing local governments millions of dollars.
• The vast majority of attacks target only computer systems, however sophisticated attacks against utilities and infrastructure, such as electrical grids, have occurred.

Table 4-15 Hazard Summary – Cyber Attack
Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Significant Likely NA Medium No
City of Ceres Significant Likely NA Medium No
City of Hughson Significant Likely NA Medium No
City of Modesto Significant Likely NA Medium No
City of Newman Significant Likely NA Medium No
City of Oakdale Significant Likely NA Medium No
City of Patterson Significant Likely NA Medium No
City of Riverbank Significant Likely NA Medium No
City of Turlock Significant Likely NA Medium No
City of Waterford Significant Likely NA Medium No
County Office of Education Significant Likely NA Medium No

4.3.4 Dam Incidents
Hazard/Problem Description
Dam failure is the breakdown, collapse or other failure of a dam structure characterized by the uncontrolled release of impounded water that results in downstream flooding. In the event of a dam failure, the energy of the water stored behind even a small dam is capable of causing loss of life and severe property damage if development exists downstream. An uncontrolled breach is the unintentional discharge from the impounded water body and is considered a failure. Dam failure can result from natural events or humaninduced events. Dams have received more attention recently in the emergency management community as a potential target for terrorist acts.

Dams are built for a variety of uses, including flood protection, power generation, agriculture, water supply, and recreation. When dams are constructed for flood protection, they usually are engineered to withstand a flood with a computed risk of occurrence. For example, a dam may be designed to contain a flood at a location on a stream that has a certain probability of occurring in any one year. If prolonged periods of rainfall and flooding occur that exceed the design requirements, that structure may be overtopped and fail.

Overtopping is the primary cause of earthen dam failure in the United States. Dam failures can also result from any one or a combination of the following causes:
• Earthquake
• Inadequate spillway capacity resulting in excess overtopping flows • Internal erosion caused by embankment or foundation leakage or piping or rodent activity • Improper design
• Improper maintenance
• Negligent operation
• Failure of upstream dams on the same waterway
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Water released by a failed dam generates tremendous energy and can cause a flood that is catastrophic to life and property. A catastrophic dam failure could challenge local response capabilities and require evacuations to save lives. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Major loss of life could result as well as potentially catastrophic effects to roads, bridges, and homes. Associated water quality and health concerns could also be issues. Factors that influence the potential severity of a full or partial dam failure are the amount of water impounded; the density, type, and value of development and infrastructure located downstream; and the speed of failure.

The best way to mitigate dam failure is through the proper construction, inspection, maintenance, and operation of the dam.

Controlled release or spillway flooding – Spillways are designed to relieve pressure on dams and prevent dam failures. Flooding downstream often results when spillways flow, though the potential for flooding as a result of discharge from dam outlet structures can also result from excessive rain events.

However, controlled releases of water from dams is a measure that can prevent or minimize spillway flooding or structure failure, by regulating capacity in a managed way. Even controlled releases can lead to unwanted or unpredicted flooding, depending on environmental and weather conditions, or even human error.

In general, there are three types of dams: concrete arch or hydraulic fill, earth-rockfill, and concrete gravity.

Each type of dam has different failure characteristics. A concrete arch or hydraulic fill dam can fail almost instantaneously: the flood wave builds up rapidly to a peak then gradually declines. An earth-rockfill dam fails gradually due to erosion of the breach: the downstream flood wave will build gradually to a peak and then decline until the reservoir is empty. And a concrete gravity dam can fail instantaneously or gradually with a corresponding buildup and decline of the flood wave.

Geographic Area
Significant – According to the California Department of Water Resources’ (DWR) Jurisdictional Dams and the National Inventory of Dams (NID) databases there are 18 dams of concern to Stanislaus County; five of which are in the County and 13 upstream of the County. Table 4-16 lists the high and significant hazard dams within and upstream of Stanislaus County. Figure 4-8 shows where the high and significant hazard dams are located, and the potential inundation areas based on the best available data. It is important to note that the inundation areas shown do not represent all dams that pose a risk; some of this information is not available in GIS or allowed for release in a public document. Virtually no urban area except the cities of Patterson and Newman in the County is free from flooding in the event of dam failure. Potential impacts are greatest for all the other major cities in Stanislaus County as well as urban communities such as Knights Ferry, Hickman, Denair, and Keyes.
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Figure 4-8 Stanislaus County Dam Inundation Map
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Table 4-16 Dams of Concern Within and Upstream of Stanislaus County County Dam Name Dam Owner/Operator River Downstream City Normal Storage
Capacity (AcreFeet)
Emergency
Action Plan
(EAP)?
NID
Hazard
Rating

CA DSOD
Hazard
Rating*
Stanislaus
Modesto
Reservoir MID TR Tuolumne RV River Waterford, Hughson, Ceres, Modesto 40,000 No High Extremely High Woodward SSJID Simmons Creek 49,340 Yes High Extremely
High
Turlock Lake TID TR Tuolumne RV
River Waterford, Hughson, Ceres, Modesto 63,406 Yes High High Modesto Effluent
Storage City of Modesto Off-streamRiver Modesto 7,830 No Significant Significant Conagra Aerated
and Settling Ponds
ConAgra Grocery
Products Company,
LLC
Off-Stream
River Oakdale 140 No High High
Tuolumne
Don Pedro
(In Old Plan) TID Tuolumne River Waterford, Hughson, Turlock, Ceres, Modesto, Patterson. Newman, Riverbank 2,030,000 Yes High Extremely High Don Pedro Dike A TID Tuolumne River Waterford, Hughson, Turlock, Ceres, Modesto, Patterson. Newman, Riverbank 2,030,000 Yes Significant Don Pedro Dike B TID Tuolumne River Waterford, Hughson, Turlock, Ceres, Modesto, Patterson. Newman, Riverbank 2,030,000 Yes High Don Pedro Dike C TID Tuolumne River Waterford, Hughson, Turlock, Ceres, Modesto, Patterson. Newman, Riverbank 2,030,000 Yes Significant Relief PG&E Summit Creek Oakdale, Riverbank, Modesto 15,600 Yes High Extremely High
Calaveras
Goodwin Tri-Dam Project Stanislaus River Oakdale 500 Yes High High New Melones
(in Old Plan) Bureau of Reclamation Stanislaus River Oakdale, Riverbank and Modesto 2,870,000 Yes High Tulloch (in GP) SSJID Stanislaus River Oakdale, Riverbank 68,400 Yes High Extremely High
Mariposa
Exchequer Dike Merced Irrigation
District Merced River Snelling 1,100,000 Yes High
Exchequer Main
(New Exchequer)
(In Old Plan)
Merced Irrigation
District Turlock, Modesto,
Ceres Snelling 1,100,000 Yes High Extremely High
Mcswain Merced Irrigation
District
Modesto,
Patterson Snelling 9,730 Yes High High
Merced San Luis Reservoir
(in GP)
Bureau of Reclamation,
California DWR
The California
Delta 2,031,000
Fresno Pine Flat (in GP) USACE – Sacramento
District Kings River 1,000,000 Yes High
Sources: California DSOD and the NID
* DSOD added a fourth category (“Extremely High”) to the FEMA categories for downstream hazard potential. Extremely High is defined as Expected to cause considerable loss of human life or would result in an inundation area with a population of 1,000 or more. 884
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There were some data limitation associated with the risk assessment for dam incidents. Analysis using inundation data and mapping associated with New Melones, Pine Flat and San Luis dams was not possible for the plan due to information being considered sensitive and restricted, per communication with OES and the dam owners. As a result, the dam risk assessment does not quantify the entire risk to the County and the nine participating jurisdictions in the event of a dam incident. However, these deficiencies have been noted and a qualitative summary of risk is provided instead.

Extent (Magnitude/Severity)
Catastrophic – Standard practice among federal and state dam safety offices is to classify a dam according to the potential impact a dam failure (breach) or mis-operation (unscheduled release) would have on downstream areas. The hazard potential classification system categorizes dams based on the probable loss of human life and the impacts on economic, environmental and lifeline facilities. The U.S. Army Corp of Engineers uses three categories to classify a dam’s potential hazard to life and property:
• High hazard indicates that a failure would most probably result in the loss of life. • Significant hazard indicates that a failure could result in appreciable property damage. • Low hazard indicates that failure would result in only minimal property damage and loss of life is unlikely.
• Undetermined hazard dams have not been rated or their hazard rating is not known.

In addition to these, high, significant, and low hazard classifications the California DSOD adds the fourth category of “Extremely High”. The DSOD defines this fourth category as “expected to cause considerable loss of human life or would result in an inundation area with a population of 1,000 or more (DSOD 2020).

As shown in Table 4-16, five dams – Modesto Reservoir, Woodward, Don Pedro, Tulloch and New Exchequer dams are classified as “Extremely High”.

Since the County has several high and significant hazard dams, there is potential for loss of life and property damage. The inundation areas for each of the dams are generally downstream and include large rural and urban areas on the valley floor below the dams. Adjacent jurisdictions could also be affected by a dam failure. The extent of impacts depends on the nature of failure and location of the dam. The largest populations potentially at risk would be in Modesto, Ceres, Hughson, and Turlock. As mentioned previously, except Patterson and Newman, all the major cities would be impacted were a dam to fail and flood downstream. The hazard risk also applies to the County’s most urban communities.

A severe storm, earthquake or erosion of the embankment and foundation leakage may cause the collapse and structural failure of dams in Stanislaus County or other nearby counties. Seismic activity may also cause inundation by the action of a seismically induced wave that overtops the dam without causing failure of the dam, but significant flooding downstream. Landslides flowing into lakes and reservoirs may also cause dams to fail or overtop.

Past Occurrences
There is no history of dam failure affecting the County, but according to the HMPC there have been recurring issues with flooding due to high flows released below dams in the area.

Probability of Future Occurrences
Unlikely – The County remains at risk to dam failures from numerous dams under a variety of ownership and control and of varying ages and conditions. However, based on historical experience dam failure is unlikely in the area based on the frequency of past dam incidents. Dams are regulated and inspected by either the State of California’s DSOD or the Federal Energy Regulatory Commission (FERC) or both with follow up written inspection reports. There have been no findings that would raise concern for a potential dam failure. Nevertheless, given the number of dams of concern in the County, the potential exists for future dam failures in Stanislaus County, but the likelihood of this is low. Uncontrolled or controlled release flooding as well as spillway flooding below dams due to excessive rain or runoff are more likely to occur than failures.
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Climate Change Considerations
UC Davis researchers discussed the effects of climate change on reservoir operations in a journal published in 2014. This journal and other relevant studies imply that climate change will impact the traditional operation measures and flow regimes used for dams because river conditions and water levels will be fluctuating due to climate change. For example, climate change may worsen drought conditions, which lessen the water available while climate change can also produce intense sudden storms that causes water levels to suddenly increase. Therefore, reservoir operators may need to change operations to mitigate for climate change’s impact on rivers and overall water levels (Rheinheimer and Viers 2014).

However, the potential for climate change to affect the likelihood of dam failure is not fully understood now.

With a potential for more extreme precipitation events as a result of climate change, this could lead to large inflows to reservoirs. However, this could be offset by generally lowering reservoir levels if storage water resources become more limited or stretched in the future due to climate change, drought and/or population growth.

Vulnerability Assessment
A dam incident can range from a small, uncontrolled release to a catastrophic failure. Vulnerability to dam failures is confined to the areas and populations subject to inundation downstream of the facility. Secondary losses would include loss of the multi-use functions of the dam itself and associated revenues that accompany those functions.

General Property
In the unlikely event of a complete dam failure, the majority of the populated areas within Stanislaus County are impacted, specifically, those areas along the Stanislaus, Tuolumne and San Joaquin Rivers. Areas around Dry Creek will also flood. Inundation due to dam failure within the San Joaquin Valley is a low probability but high-risk hazard. The potential risk for inundation of property is present in nearly all of the developed areas of Stanislaus County; however, catastrophic failure or flood release of water from multiple dams at a single point in time is considered to be extremely unlikely.

In general, communities located below a high or significant hazard dam and along a waterway are potentially exposed to the impacts of a dam failure. Inundation maps that identify anticipated flooded areas (which may not coincide with known floodplains) are typically produced for all high hazard dams and included in the Emergency Action Plan (EAP) required for each dam. The FERC also requires annual training and exercises for each individual EAP. Stanislaus County maintains copies of the dam EAPs at its Emergency Operations Center (EOC) and participates in exercises with the dam operators.

A GIS layer that contained inundation maps for 10 of the 18 high and significant hazard dams that affect the County was analyzed to quantify risk across the Planning Area. Table 4-17 summarizes the results of the GIS analysis and includes a population estimate based on the number of residential parcels exposed, multiplied by an average household size estimate from the U.S. Census. Exposure estimates from failure of other high hazard dams were not possible due to data restrictions and/or limitations.

Table 4-17 Summary of Dam Inundation by Jurisdiction
Jurisdiction Improved
Parcel
Count
Improved Value Estimated Content
Value
Total Value Population
Ceres 11,462 $2,511,485,475 $1,760,538,649 $4,272,024,124 38,906 Hughson 2,086 $494,398,275 $313,490,178 $807,888,453 5,853 Modesto 60,673 $14,126,321,781 $9,767,800,876 $23,894,122,657 161,011 Oakdale 408 $92,838,755 $51,332,522 $144,171,277 1,106
Riverbank 1,601 $438,053,010 $257,818,591 $695,871,601 5,415 Turlock 19,413 $5,311,625,963 $3,985,984,895 $9,297,610,858 49,737 Waterford 2,376 $389,884,917 $233,731,703 $623,616,620 7,651 Unincorporated 25,617 $5,856,860,233 $5,498,466,160 $11,355,326,393 46,718 Total 123,636 $29,221,468,409 $21,869,163,571 $51,090,631,980 316,395 Source: California DSOD, NID, Stanislaus County Assessor’s Office 886
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People
Persons located underneath or downstream of a dam are at risk of a dam failure, though the level of risk can be tempered by topography (specifically where populations are located within the inundation path of a dam), amount of water in the reservoir and time of day of the breach. Injuries and fatalities can occur from debris, bodily injury, and drowning. Once a dam has breached, standing water presents all the same hazards to people as floodwater from other sources. People in the inundation area may need to be evacuated, cared for, and possibly permanently relocated. Impacts could include thousands of evacuations and likely hundreds of casualties, depending on the dam involved.

The populations most vulnerable are those that have the least time to evacuate and need assistance.

Populations that may need assistance to evacuate include the elderly, disabled and young. The vulnerable population also includes those who may not have adequate warning to evacuation from emergency notification systems. The loss of life is impacted by the amount of early warning time first responders and the public has prior to the incident.

Specific population impacts are noted in Table 4-17, and total people at risk were calculated by multiplying the average number of persons per household in Stanislaus County (3.09) and each applicable incorporated jurisdiction (Ceres 3.66, Hughson 3, Modesto 2.9, Newman 3.41, Oakdale 2.91, Patterson

3.7, Riverbank 3.44, Turlock 2.87, and Waterford 3.57) times the number of residential parcels where dam inundation occurs. Based on the best available data accessible to the HMPC at this time of this analysis, the City of Modesto has the most people (161,011) potentially exposed to a dam inundation event, followed by City of Turlock and the unincorporated areas of the County with potentially 49,737 and 46,718 people exposed to a dam inundation event, respectively.

Social Vulnerability
As shown in Figure 4-3 Overall Social Vulnerability in Stanislaus County based on the SoVI, by Census Tracts, the areas with the highest level of social vulnerability in the County are in the central, southern, and southwestern portions of the County, including some of the incorporated jurisdictions such as the Cities of Modesto, Ceres, and Turlock. These socially vulnerable areas are also within the inundation areas of New Exchequer and Don Pedro dams. Therefore, socially vulnerable populations who live in these areas are exposed to a higher risk of dam inundation incidents.

Government Services
Short‐term accessibility issues may limit staffs’ abilities to perform routine duties or report to work locations, and delivery of services may be affected. Damage to facilities/personnel in incident area may require temporary relocation of some operations. Regulatory waivers may be needed locally. Fulfillment of some contracts may be difficult.

Responders in flooded areas at the time of incident or assisting in evacuations could be at risk. Impacts to transportation corridors and communications lines could affect first responders’ ability to effectively respond. Public confidence in government may be challenged by the public if planning, response, and recovery are not timely and effective, regardless of the dam owner.

Critical Facilities and Infrastructure
A total dam failure can cause catastrophic impacts to areas downstream of the water body, including critical infrastructure. Any critical asset located under the dam in an inundation area would be susceptible to the impacts of a dam failure. Of particular risk would be roads and bridges that could be vulnerable to washouts, further complicating response and recovery by cutting off impacted areas. Impacts to cities would affect key infrastructure including hospitals, fire stations, clinics, and businesses.

Based on the critical facility inventory considered in this plan update and intersected with the dam inundation extents available, 1,006 critical facilities were found to be potentially at risk. The unincorporated County has the greatest number of facilities at-risk followed by City of Modesto and City of Turlock. These at-risk facilities are listed in the tables below by jurisdiction and critical facility classification as based on the FEMA Lifeline categories.
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Table 4-18 Critical Facilities in Dam Inundation Areas – Estimates by Jurisdiction and FEMA Lifeline
Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Ceres 17 4 2 1 9 14 14 61
Hughson 1 - 17 1 2 10 3 34
Modesto 52 24 25 9 112 90 32 344
Newman - - - - - - - -
Oakdale - - - 1 1 1 - 3
Patterson - - 1 - - - - 1
Riverbank - 1 - 1 - - 1 3
Turlock 13 7 13 21 27 23 20 124
Waterford - - 6 - - 7 3 16
Unincorporated 107 40 18 27 14 59 153 418
Other Counties 1 - - - 1 - - 2
Total 191 76 82 61 166 204 226 1,006
Source: Homeland Infrastructure Foundation – Level Data, Stanislaus County, Cities of Newman, and Hughson Economy
Extensive and long-lasting economic impacts could result from a major dam failure including the long-term loss of water in a reservoir after a failure event. Based on the analysis there are approximately 8,612 buildings that are designated as farm and agricultural properties potentially exposed to dam inundation event. A major dam incident and loss of water from the associated reservoir could include direct business and specifically impacts to the agricultural industry, resulting in damages and indirect disruption of the local economy. Economic impacts related to agriculture in the unincorporated areas of the County would be the most severe. According to the 2020 Stanislaus County Agriculture Report, the value of agricultural commodities produced in Stanislaus County was $3.5 billion.

Historic, Cultural and Natural Resources
Dam failure effects on the environment would be similar to those caused by flooding from other causes.

Water could erode stream channels and topsoil and cover the environment with debris. For the most part the environment is resilient and would be able to rebound from whatever damages occurred, though this process could take years. However, historic and cultural resources could be affected just as housing or critical infrastructures would, were a dam to fail and cause downstream inundation that could further erode surfaces or cause scouring of structural foundations.

Future Development
GIS was used to analyze parcels exposed to dam inundation areas that are located within each city’s SOI boundary. These parcels are also included in Table 4-18, and they fall under “Unincorporated” in terms of their jurisdiction. Parcels shown below in Table 4-19 are those that fall within each jurisdiction’s SOI and are exposed to dam inundation areas. The results shown in Table 4-19 show that there is a total of 9,599 improved parcels worth more than $4.36 billion currently exposed to dam inundation within the SOI areas. 23,465 people would also be exposed to dam inundation within the SOI areas. 888
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Table 4-19 Total Dam Inundation Summary by Dam within Sphere of Influence Areas Jurisdiction Improved
Parcel Count
Improved
Value
Estimated
Content Value
Total Value Population
Ceres 1,974 $268,710,296 $200,638,561 $469,348,857 5,995 Hughson 76 $19,505,347 $18,760,196 $38,265,543 9
Modesto 6,691 $1,673,437,332 $1,885,783,247 $3,559,220,579 15,907 Newman 4 $705,813 $705,813 $1,411,626 -
Oakdale 51 $12,457,109 $6,404,678 $18,861,787 134
Riverbank 65 $11,209,681 $8,512,805 $19,722,486 107
Turlock 656 $122,502,912 $105,060,814 $227,563,726 1,300 Waterford 82 $15,139,178 $14,810,922 $29,950,100 14
Total 9,599 $2,123,667,668 $2,240,677,035 $4,364,344,703 23,465 Sources: California DSOS, NID, Stanislaus County Assessor’s Office The areas located in the SOI for each incorporated jurisdiction are areas each city plans to grow into and potentially slated for future development. In addition to the SOI areas, there are also 91 vacant parcels countywide that are within dam inundation areas. These areas should take into consideration potential impacts from dam failure risk upstream and should attempt to overlay the existing dam inundation maps with proposed future development.

In the case of a dam failure, inundation would likely follow some existing FEMA-mapped floodplains, which contain development restrictions for areas in the 1% annual chance floodplain, but it could exceed those floodplains and affect areas that are not regulated for flood hazards. Also, of note is that development below a low or undetermined hazard dam could increase its hazard rating, while there are quite a few low hazard dams in the County. Finally, added development could compromise dams and reservoir resources if populations depend on them for critical needs such as potable water during or after a dam failure event.

The Stanislaus County Board of Supervisors has maintained support for the preservation of agricultural resources through the adoption of the Agricultural Element of the County’s General Plan. Related policies, such as encouraging higher density development and in-filling of already existing urban areas as well as directing away development from the County’s most productive agricultural areas are in place to reduce development pressures on agricultural lands.

There has been no significant change in development in the unincorporated areas impacted by dam failure within Stanislaus County since the last LHMP update. The proposed industrial development at the Crows Landing Airfield on the western side of the County along Interstate 5 would be impacted by inundation caused by the failure of the San Luis Dam and Exchequer Dam. Because the Crows Landing Industrial Business Park is currently in the CEQA process no firm date for development has been identified.

Risk Summary
• There are 18 dams of concern for Stanislaus County. Five are within the County (four High Hazard Potential and one Significant) and 13 dams are upstream of the County (10 High Hazard and two Significant).
• Of the four high hazard potential rated dams in the County, two (Modesto Reservoir and Woodward) are rated as “Extremely High” by the State of California DSOD. • Countywide there are a minimum of 123,636 parcels at risk based on limited available inundation mapping, with greatest number of buildings exposed in the City of Modesto (60,673) followed by the unincorporated area (26,617), City of Turlock (19,413) and City of Ceres (11,462). • Residential property types make up the most parcels (104,648) at risk of flooding from dam failures, followed by commercial (4,113).
• An estimated 316,395 people countywide might be displaced from their homes based the location of their residences along the inundation areas; actual amounts would vary. • A total of 1,006 critical facilities are within dam inundation areas. The greatest number are unincorporated Stanislaus County (418) and Transportation lifeline is most at risk countywide. • Related Hazards – drought, flooding, earthquake/liquefaction, landslide, and severe weather. 889
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Table 4-20 Hazard Risk Summary by Jurisdiction – Dam Incidents Jurisdiction Geographic
Area
Probability
of Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Significant Unlikely Catastrophic Medium Yes City of Ceres Extensive Unlikely Catastrophic High Yes
City of Hughson Extensive Unlikely Catastrophic Medium Yes City of Modesto Extensive Unlikely Catastrophic High Yes City of Newman Limited Unlikely Negligible Low No
City of Oakdale Extensive Unlikely Catastrophic Medium Yes City of Patterson Limited Unlikely Negligible Low No
City of Riverbank Significant Unlikely Limited Medium Yes City of Turlock Extensive Unlikely Catastrophic High Yes City of Waterford Extensive Unlikely Catastrophic High Yes County Office of Education Extensive Unlikely Catastrophic High Yes

4.3.5 Drought
Hazard/Problem Description
Drought is a gradual phenomenon. Normally, one dry year does not constitute a drought in California, but rather serves as a reminder of the need to plan for droughts. California's extensive system of water supply infrastructure (reservoirs, groundwater basins, and interregional conveyance facilities) generally mitigates the effects of short‐term dry periods for most water users.

Drought can have secondary impacts. For example, drought is a major determinant of wildfire hazard, in that it creates greater propensity for fire starts and larger, more prolonged conflagrations fueled by excessively dry vegetation, along with reduced water supply for firefighting purposes. Drought is also an economic hazard. Significant economic impacts on California’s agriculture industry can occur as a result of short‐ and long‐term drought conditions; these include hardships to farmers, farm workers, packers, and shippers of agricultural products. In some cases, droughts can also cause significant increases in food prices to the consumer due to shortages.

Drought is a complex issue involving many factors—it occurs when a normal amount of moisture is not available to satisfy an area’s usual water-consuming activities. Drought can often be defined regionally based on its effects:
• Meteorological drought is defined by a period of substantially diminished precipitation duration and/or intensity. The commonly used definition of meteorological drought is an interval of time, generally on the order of months or years, during which the actual moisture supply at a given place consistently falls below the climatically appropriate moisture supply.
• Agricultural drought occurs when there is inadequate soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought usually occurs after or during meteorological drought, but before hydrological drought and can affect livestock and other dry-land agricultural operations. • Hydrological drought refers to deficiencies in surface and subsurface water supplies. It is measured as stream flow, snowpack, and as lake, reservoir, and groundwater levels. There is usually a delay between lack of rain or snow and less measurable water in streams, lakes, and reservoirs. Therefore, hydrological measurements tend to lag other drought indicators. • Socioeconomic drought occurs when physical water shortages start to affect the health, well-being, and quality of life of the people, or when the drought starts to affect the supply and demand of an economic product.
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The California DWR says the following about drought:
“One dry year does not normally constitute a drought in California. California’s extensive system of water supply infrastructure—its reservoirs, groundwater basins, and interregional conveyance facilities—mitigates the effect of short-term dry periods for most water users. Defining when a drought begins is a function of drought impacts to water users. Hydrologic conditions constituting a drought for water users in one location may not constitute a drought for water users elsewhere, or for water users having a different water supply. Individual water suppliers may use criteria such as rainfall/runoff, amount of water in storage, or expected supply from a water wholesaler to define their water supply conditions.”
The drought issue in California is further compounded by water rights. Water is a commodity possessed under a variety of legal doctrines. The prioritization of water rights between farming and federally protected fish habitats in California is part of this issue.

Drought impacts are wide-reaching and may be economic, environmental, and/or societal. The most significant impacts associated with drought in the Planning Area are those related to water intensive activities such as agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. Also, during a drought, allocations go down, which results in reduced water availability.

Voluntary water conservation measures are typically implemented during extended droughts. A reduction of electric power generation and water quality deterioration are also potential problems that can occur as a result of drought conditions. The reduced demand for electrical power generation is commonly linked to higher electricity costs due to the loss of hydropower supplies. Water quality deterioration is due to lower levels of precipitation and limited water storage supply. Drought conditions can also cause soil to compact and not absorb water well, potentially making an area more susceptible to flooding.

Geographic Area
Extensive – Drought is a regional hazard, and at its worst can affect the entire State of California with varying levels of dryness and drought activity. It is safe to assume that unless the drought event is at its very beginning or very end, if any area of Stanislaus County is affected by any level of drought, the other areas of the County are experiencing varying effects as well.

Sustainable Groundwater Management Act (SGMA) of 2014
In January 2014, Governor Brown declared an emergency proclamation due to multiple years of drought.

The proclamation called on citizens to reduce water use by 20 percent; with a subsequent Executive Order in April 2015 that directed urban water agencies to reduce water use by 25 percent (Ken Topping 2016). In September 2014, the Governor signed a three-bill package (California SBs 1168 and 1319, and Assembly Bill 1739), known as the Sustainable Groundwater Management Act of 2014 (SGMA). The SGMA provides for the establishment of local Groundwater Sustainability Agencies (GSAs) to manage groundwater sustainably within the groundwater subbasins defined by the California DWR. Within Stanislaus County there are portions of four groundwater subbasins, Eastern San Joaquin, Modesto, Turlock (east and west), Delta-Mendota, that are required under SGMA to conduct sustainable groundwater management. Each of the four subbasins are required to develop and implement a Groundwater Sustainable Plan (GSP) by 2020 or 2022. As of August 2021, GSAs formed for the four subbasins as shown in Table 4-21.

Table 4-21 Groundwater Sustainability Agencies (GSAs) in Stanislaus County Subbasin Groundwater Sustainability Agency (GSA)
Eastern San Joaquin
Eastside San Joaquin GSA
Central Delta Water Agency
Central San Joaquin Water Conservation District
City of Lodi GSA
City of Manteca GSA
City of Stockton GSA
Linden County Water District
Lockeford Community Services District
North San Joaquin Water Conservation District
Oakdale Irrigation District
San Joaquin County GSA
South Delta Water Agency
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Subbasin Groundwater Sustainability Agency (GSA)
South San Joaquin GSA
Stanislaus Subbasin GSA
Stockton East Water District
Woodbridge Irrigation District GSA
Modesto*
City of Modesto
City of Oakdale
City of Riverbank
City of Waterford
Modesto Irrigation District
Oakdale Irrigation District
Stanislaus County
Turlock West Turlock GSA
East Turlock GSA
Delta-Mendota
City of Dos Palos GSA
City of Gustine GSA
City of Los Banos GSA
Central Delta-Mendota GSA
Turner Island Delta-Mendota GSA
Northwestern Delta-Mendota GSA
Grassland Water District GSA
San Joaquin River Exchange Contractors GSA
County of Stanislaus Chowchilla GSA
* In 2017, member agencies of the Stanislaus and Tuolumne Rivers Groundwater Basin Association (STRGBA) - City of Modesto, Modesto Irrigation District, City of Oakdale, Oakdale Irrigation District, City of Riverbank, City of Waterford, and Stanislaus County – formed as a GSA.

Source: Stanislaus County Water Resources https://www.co.Stanislaus.ca.us/3140/Sustainable-Groundwater---SGMA Extent (Magnitude/Severity)
Critical – The magnitude of a drought’s impact is directly related to the severity and length. The severity of a drought depends on water availability and moisture deficiency, the time period, and the size and location of the affected area. The longer the drought persists and the larger the area impacted, the more severe the potential impacts. Droughts can be a short-term event over several months or a long-term event that lasts for years or even decades. In Stanislaus County, the onset of drought is often signaled by a lack of significant winter precipitation and snowfall (moisture deficiency) in the Sierra Nevada Mountains. Droughts typically do not result in direct impacts on people or property, but they can have significant impacts on agriculture, which can indirectly impact people and property. Hot and dry conditions that persist into spring, summer, and fall can aggravate drought conditions, making the effects of drought more pronounced as water demands increase during the growing season and summer months. Impacts increase with the length of a drought, as carry-over supplies in reservoirs are depleted and water levels in groundwater basins decline (California DWR 2012).

The U.S. Drought Monitor is an accepted and widely used site for obtaining and summarizing drought information, as it integrates data from several other sources including the Palmer Drought Index, Soil Moisture Models, U.S. Geological Survey Weekly Stream Flows, Standardized Precipitation Index, and the Satellite Vegetation Health Index. It includes drought intensity categories for measuring dry conditions across counties, states, and regions of the U.S., so that drought can be quantified. These categories range from “abnormally dry” to “exceptional drought.” The following figures provide “snapshots in time” of the drought conditions in California as of August 2016 (during the period of the last multi-year drought in Stanislaus County and the state, from 2012- 2017) and August 24, 2021. The snapshots selected are instrumental in depicting both the historic and potential change in drought’s geographic range and severity in the County (circled in blue).

Note: The Drought Monitor maps integrate data from several sources including the Palmer Drought Index, Soil Moisture Models, U.S. Geological Survey Weekly Stream flows, Standardized Precipitation Index, and Satellite Vegetation Health Index. The drought status in California is noted on the following graphic from the National Drought Mitigation Center.
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Figure 4-9 U.S. Drought Monitor for California: August 23, 2016 893
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Figure 4-10 U.S. Drought Monitor for California: August 24, 2021 Past Occurrences
Historically, California has experienced severe drought conditions. The state’s available record for determining hydrologic risks is short, only going back about 100 years. Recent droughts affecting Stanislaus County are summarized below using data from Cal OES and from the County Agricultural Commissioner’s Office.
• 1928-1937 – This drought affected the entire state and is the longest, most severe drought on record with a recurrence interval of greater than 100 years.
• 1947-1950 – Drought affected the entire state but was most extreme in Southern California. The drought in winter of 1950 affected the area from the Kern River basin north to the American River basin.

The drought caused two deaths and $33 million in damages. • 1976-1977 – The drought of 1976-1977 was most severe in the northern three-quarters of California, but the impact was experienced statewide because of the dependence of Southern California on water transfers from the north. FEMA declared emergency declaration for Stanislaus County and the Public Assistance program was declared. Year 1977 was the driest year of record at almost all gauging stations in the affected area in California, and the water year 1976 was among the five driest in the central and northern Sierra Nevada. The two-year deficiency in runoff accumulated during the drought is unequalled at gauging stations in the affected area; and this deficiency has a recurrence interval that exceeds 80 years. Crop damages statewide were $2.67 billion. • 1987-1992 – California experienced a serious drought due to low precipitation and runoff levels. During this multi-year, multi-county drought, the runoff from the San Joaquin Valley was 47 percent of average.

In 1991, the U.S. Department of Agriculture Economic Research Report Agricultural Outlook reported 894
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that the Stanislaus River flow would be inadequate to provide sufficient water for agricultural uses for the fifth consecutive year. A USDA drought disaster declaration was declared. • 2004-2005 – On January 15, 2005, the USDA designated 53 of California’s 58 counties as natural disaster areas due to damages and losses caused by extreme drought. • 2012 – 2017 – In September 2012, the USDA designated Stanislaus County a contiguous disaster area due to drought that occurred since January 1, 2012. In January 2014, the Governor proclaimed a state of emergency and directed state officials to take all necessary actions to prepare for these drought conditions: to assist farmers and communities that are economically impacted by dry conditions and to ensure the State can respond if Californians face drinking water shortages. The Governor also directed state agencies to use less water and hire more firefighters and initiated an expansive water conservation public awareness campaign. Drought produced severe impacts to water wells throughout the Planning Area, with a high number of wells running dry. Land subsidence due to increased groundwater pumping also occurred in areas of the San Joaquin Valley. Crop damage was also widespread. Water allotments were drastically reduced in many towns and water agencies, with extremely high costs for procuring water. In addition, job loss occurred with many families requiring food supply assistance, and water supply assistance provided to homeowners with dry wells. According to a report released by UC Davis Center for Watershed Sciences, the 2014 California drought cost the state's agriculture industry about $1 billion in lost revenue, with a total statewide economic cost of the drought calculated to be $2.2 billion. The 2014 drought, the report says, is responsible for the greatest water loss ever seen in California agriculture - about one-third less than normal. The report calls the groundwater situation in California "a slow-moving train wreck." (NCICS 2019). According to the 2018 California SHMP, by the time the drought was declared officially in 2017, the State had been declared a federal disaster area and had expended $6.6 billion in drought response and mitigation programs.

As shown in Table 4-4, of the 21 total Secretary of Agricultural Disaster Designations for Stanislaus County in the past 10 years, 16 were specific to drought. In addition to the USDA designations there have also been one federal disaster declarations due to drought in the County (refer to Table 4-3).

The National Drought Mitigation Center developed the Drought Impact Reporter in response to the need for a national drought impact database for the United States. Information comes from a variety of sources:
online, 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. The Drought Impact Reporter contains information on 281 impact reports from droughts that affected Stanislaus County between 2000 and 2021. Most of the impacts (228) were classified as “relief, response and restrictions”, “water supply and quality” (181) and “agriculture” (178). Other impacts included “society and public health” (94), “business and industry” (46), “general awareness” (24) “plants and wildlife” (15), “fire” (8), and “energy” (4). These categories are described as follows:
• Relief, Response, and Restrictions (228) – This category refers to drought effects associated with disaster declarations, aid programs, requests for disaster declaration or aid, water restrictions, or fire restrictions. Examples include disaster declarations, aid programs, USDA Secretarial Disaster Declarations, Small Business Association Disaster Declarations, government relief and response programs, state-level water shortage or water emergency declarations, county-level declarations, a declared “state of emergency,” requests for declarations or aid, nonprofit organization-based relief, water restrictions, fire restrictions, National Weather Service (NWS) Red Flag Warnings, and declaration of drought watches or warnings.
• Water Supply and Quality (181) – Drought effects associated with water supply and water quality include dry wells, voluntary and mandatory water restrictions, changes in water rates, increasing of water restrictions, increases in requests for new well permits, changes in water use due to water restrictions, greater water demand, decreases in water allocation or allotments, installation or alteration of water pumps or water intakes, changes to allowable water contaminants, water line damage or repairs due to drought stress, drinking water turbidity, change in water color or odor, declaration of drought watches or warnings, and mitigation activities. • Agriculture (178) – Drought effects associated with agriculture, farming, aquaculture, horticulture, forestry, or ranching. Examples of drought-induced agricultural impacts include damage to crop quality; income loss for farmers due to reduced crop yields; reduced productivity of cropland; insect infestation; plant disease; increased irrigation costs; cost of new or supplemental water resource development (wells, dams, pipelines) for agriculture; reduced productivity of rangeland; forced reduction of 895
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foundation stock; closure/limitation of public lands to grazing; high cost or unavailability of water for livestock, Christmas tree farms, forestry, raising domesticated horses, bees, fish, shellfish, or horticulture.
• Society and Public Health (94) – Drought effects associated with human, public and social health include: health-related problems related to reduced water quantity or quality, such as increased concentration of contaminants; loss of human life (e.g., from heat stress, suicide); increased respiratory ailments; increased disease caused by wildlife concentrations; increased human disease caused by changes in insect carrier populations; population migration (rural to urban areas, migrants into the United States); loss of aesthetic values; change in daily activities (non-recreational, like putting a bucket in the shower to catch water); elevated stress levels; meetings to discuss drought; communities creating drought plans; lawmakers altering penalties for violation of water restrictions; demand for higher water rates; cultural/historical discoveries from low water levels; cancellation of fundraising events; cancellation/alteration of festivals or holiday traditions; stockpiling water; public service announcements and drought information websites; protests; and conflicts within the community due to competition for water.
• Business and Industry (46) – This category tracks drought’s effects on non-agriculture and nontourism businesses, such as lawn care, recreational vehicles, or gear dealers, and plant nurseries.

Typical impacts include reduction or loss of demand for goods or services, reduction in employment, variation in number of calls for service, late opening or early closure for the season, bankruptcy, permanent store closure, and other economic impacts.
• General Awareness (24) – General Awareness applies only to media reports and usually indicates that people are concerned about drought, but no specific impact has occurred yet or the information is too general to use for an impact.
• Plants and Wildlife (15) – Drought effects associated with unmanaged plants and wildlife, both aquatic and terrestrial, include: loss of biodiversity of plants or wildlife; loss of trees from rural or urban landscapes, shelterbelts, or wooded conservation areas; reduction and degradation of fish and wildlife habitat; lack of feed and drinking water; greater mortality due to increased contact with agricultural producers (as predators seek food from farms and producers are less tolerant of the intrusion); disease; increased vulnerability to predation (from species concentrated near water); migration and concentration (loss of wildlife in some areas and too much wildlife in others); increased stress on endangered species; salinity levels affecting wildlife; wildlife encroaching into urban areas; and loss of wetlands.
• Fire (8) – Drought often contributes to forest, range, rural, or urban fires, fire danger, and burning restrictions. Specific impacts include enacting or increasing burning restrictions, fireworks bans, increased fire risk, occurrence of fire (number of acres burned, number of wildfires compared to average, people displaced, etc.), state of emergency during periods of high fire danger, closure of roads or land due to fire occurrence or risk, and expenses to state and county governments of paying firefighters overtime and paying equipment (helicopter) costs. • Energy (4) – This category concerns drought's effects on power production, rates, and revenue.

Examples include production changes for both hydropower and non-hydropower providers, changes in electricity rates, revenue shortfalls and/or windfall profits, and purchase of electricity when hydropower generation is down.

Probability of Future Occurrences
Likely – Historical drought data for the County Planning Area and the San Joaquin Valley region indicate there have been five significant multi-year droughts in the last 91 years. This equates to a multi-year drought every 18 years on average, or a 5 percent chance of a drought in any given year (probability). Based on this data, droughts will likely affect the Planning Area. Given the historical occurrence of severe drought impacts throughout Stanislaus County and across the State, the HMPC understands that drought will continue to pose a high degree of risk to the entire Planning Area, potentially impacting crops, livestock, water resources, the natural environment at large, buildings and infrastructure (from cascading or compound hazards), and local economies.

In addition, although drought affects the entire planning equally, the potential impacts may be variable and specific to each jurisdiction, depending on contextual factors such as the degree of assets and activities historically impacted by drought within each jurisdiction, such as the agricultural and parks and tourism industries.
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Climate Change Considerations
Water resources in California area already experiencing stresses related to population growth, increased water demand, poor water quality, groundwater overdraft, and aging infrastructure. Scientific studies prepared for various California climate assessments and adaptations strategies also already show that drought conditions in California are likely to become more frequent and persistent over the next century due to climate change. Temperatures are warming, heat waves are more frequent, and precipitation has become increasingly variable (CNRA 2018a). According to California’s Climate Adaptation Strategy, also referred to as “Safeguarding California Plan: 2018 Update”, climate change is likely to significantly diminish California’s future water supply. As a result, the State must change its water management, as climate change will create greater competition for limited water supplies (California Natural Resources Agency 2018b). The recent drought conditions over the past decade underscore the need to examine water supply and distribution management, conservation, and use policies. California and the San Joaquin Valley region have experienced a succession of dry spells and with warmer temperatures and periodic droughts that frequently contribute to water shortages in the region.

Climate change projections of extreme prolonged droughts will exacerbate the San Joaquin Valley’s existing water supply challenges. In an average year, approximately 40 percent of the State’s total water supply comes from groundwater, and during a dry year this increases to more than half of the State’s water supply, with groundwater acting as a critical buffer against the impacts of drought and climate change (CNRA 2018).

Table 4-22 Summary of Climate Change Impacts on Water Resources Resource Type of
Impact Description
Soil Moisture Direct Prolonged dry seasons can lead to decreases in soil moisture; drier vegetation
Vegetation Indirect Longer and more intense fire season with increased extent of area burned Stream Conditions Direct Increases in water temperature; potential effects on fish Snowpack Indirect Increases in temperature will lead to decreases in snowpack Runoff Direct Warmer temperatures are likely to lead to a shift in peak runoff from spring to winter and a likely decrease in summer baseflow
Hydropower Indirect Decreased summer flows resulting from earlier snowmelt and a shift in peak runoff could affect hydropower generation during summer months Precipitation Direct Warmer winter temperatures will result in a greater percentage of precipitation falling as rain rather than as snow
Groundwater Indirect Reduction in snowpack and extended periods of drought are likely to increase dependency on groundwater
Source: http://frap.fire.ca.gov/data/assessment2010/pdfs/3.1water.pdf p. 140 Vulnerability Assessment
All of Stanislaus County is vulnerable to drought. Drought is one of the few hazards with the potential to impact all the citizens of the County through water restrictions, economic losses, and increased energy costs. The urbanized areas of the County and the agriculture industry are most likely to experience hardships associated with reduced water supply. Impacts include water restrictions associated with domestic supplies, agricultural and livestock losses and economic impacts, hydroelectric power reductions, and increased costs for water. Secondary effects include susceptibility to wildfires and increased groundwater pumping that can contribute to land subsidence problems and degraded water quality.

General Property
Based on the USDA’s RMA Crop Indemnity Reports, which were collected for the years 2007 through 2020, crop losses due to drought were only reported 2007 – 2009 and 2012 – 2014 across the County. Table 4-23 summarizes the agricultural losses. A total of $90,695 was indemnified for 1,177 acres of insured crops.
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Table 4-23 Crops Loss Due to Drought, Risk Management Agency Crop Indemnity Reports, 2007-2020
Year Crop Net Determined Acres Indemnity Amount
2007 Wheat 151.3 $9,655
2008 Wheat 43 $4,109
2009
Wheat 149 $14,142
Oats 189.9 $10,927
Barley 150 $4,500
Total 488.9 $29,569
2012
Wheat 70.5 $9,356
Oats 19.8 $902
Barley 293.5 $13,611
Total 383.8 $23,869
2013 Wheat 55.7 $9,671
2014 Wheat 55 $13,822
Grand Total 1,177.7 $90,695
Source: USDA RMA Crop Indemnity Reports, 2007-2020
People
According to this California DOF, by January 1, 2021, the County population was 555,968 people. The County’s population is currently growing at 0.2% annually. According to DOF’s projection, the County’s population is projected to reach 680,311 by the year 2060. In addition, according to the Stanislaus County Forecast Summary published by the Eberhardt School of Business at the University of The Pacific predict the County’s population growth rate to be steady fluctuating between 0.85% and 1.15% annually until 2060.

This projected population growth would add additional strain to the surface water supplies and already depleted groundwater supplies. The County Groundwater Ordinance, which prohibits the unsustainable groundwater extraction or conveyance, may help with reducing the impacts on drought on the regional groundwater supply.

The historical and potential impacts of drought on populations include agricultural sector job loss, secondary economic losses to local businesses and public recreational resources, increased cost to local and state government for large-scale water acquisition and delivery, and water rationing and water wells running dry for individuals and families. As drought is often accompanied by prolonged periods of extreme heat, negative health impacts such as dehydration can also occur, where children and elderly are most susceptible. Air quality often declines in times of drought which can affect those with respiratory ailments.

Government Services
Drought may require disaster declarations, aid programs, water restrictions, or fire restrictions. These needs could impact funding or administrative resources for other regular operations or may necessitate changes to existing operating procedures.

Water utilities are likely to face the greatest challenges to continuity of operations and delivery of services, especially during long-term widespread droughts, where opportunities for resource-sharing are limited.

Water suppliers may need to change water rates, set usage restrictions, adjust to changes in demand, address water line damage or repairs due to drought stress, account for changes in water quality, and seek alternative water supplies. Should a public water system be severely affected, the cost of shipping in outside water could total into the millions of dollars.

The impact to first responders from drought events is likely to be similar to impacts on the general public.

Public confidence may be affected because of the drought response process. Water usage restrictions and potential penalties for violations of these restrictions can cause frustration with government. Meetings to discuss drought, efforts to create community drought plans, and public service announcements and education efforts may affect public confidence. Elevated stress levels may result from these processes as well as from demand for higher water rates, cancellation of fundraising events, cancellation of festivals or holiday traditions, stockpiling water, or protests.

Critical Facilities and Infrastructure
Drought conditions rarely affect existing buildings, infrastructure, and critical infrastructure. However, severe to exceptional droughts can have significant consequences for water supply (drinking water and agriculture uses), water quality, firefighting, navigation, recreation, and other critical facilities. In some 898
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cases, when groundwater levels substantially decline, groundwater wells may need to be deepened in response. Additionally, a higher demand on the water system infrastructure can lead to disruption of service due to line breakage. Possible losses to infrastructure also include the loss of potable water.

The effect on local government infrastructure is the same as for the general public, and a drought may interrupt the normal operation of government in some places. For example, facilities dependent on wells may lose water supply.

Economy
Drought impacts to the local or regional economy can be difficult to quantify but can be extensive and longlasting depending on the circumstances during, and after a severe drought event. If water resources are limited, effects would be more severe for industries that rely on large amounts of water and any prolonged drought would intensify these impacts. Sectors critical to the economy such as commerce, distribution, agriculture, tourism, related environmental resources, municipal and industrial water supply, key city assets, energy generation, and even socioeconomic aspects can be affected due to lack of, or even reduced quality of water resources.

Agriculture in the San Joaquin Valley relies on artificial irrigation using mostly imported water or groundwater. Local droughts are expected and accommodated for; however, a prolonged statewide drought could exceed local capabilities to handle reductions of imported surface water supplies. This could lead to reductions in distribution from local water storage districts.

The costs of drought are difficult to quantify because the impacts affect so many different sectors including wildlife and natural resources, business and industry, tourism and recreation, agriculture, and individual households. Agriculture often suffers the most financial losses from drought and is Stanislaus County’s number one industry (2016 Stanislaus County Agricultural Report). For example, according to the California Integrated Climate Adaptation and Resiliency Program’s 2020 Report and 2020 Recommendations, the 2014-2017 multi-year drought was estimated to cost over $6.6 billion once it was over and the loss of 5,000 jobs in 2016 (OPR 2020).

Historic, Cultural and Natural Resources
Established in 1987, the San Joaquin River National Wildlife Refuge is 7,000 acres in size and is situated where three major rivers (Tuolumne, Stanislaus and San Joaquin) join in the San Joaquin Valley, creating a mix of habitats that provide ideal conditions for high wildlife and plant diversity. The Refuge is managed with a focus on migratory birds and endangered species (Aleutian Cackling Geese, Riparian Woodlands, Riparian Brush Rabbits, etc.). The impacts of drought on vegetation and wildlife can include death from dehydration and spread of invasive species or disease because of stressed conditions, loss of biodiversity, loss of trees in rural and urban landscapes, loss of wetlands, and degradation of habitat.

In general, environmental impacts from drought are more likely at the interface of the human and natural world. The loss of crops or livestock due to drought can have far-reaching economic effects on communities, wind and water erosion can alter the visual landscape, and dust can damage property. Water-based recreational resources are also heavily affected by drought conditions. Indirect impacts from drought arise from increased wildfire risk and greater occurrence of fire.

Future Development
With the County’s population projected to continue to steadily grow while climate change projections are showing an increased duration an intensity of drought events for the San Joaquin Valley, it will be important for each new development application to be reviewed with existing and future water supplies in mind.

Because future development encompasses all forms of property, buildings, infrastructure, critical facilities and all related populations and their functions, drought impacts to future development align with the historical and potential impacts to populations, property, natural environment, and critical facilities discussed (above).

Risk Summary
• Due to the widespread impacts in San Joaquin Valley drought is considered a High significance hazard. • There have been five multi-year droughts in the past 91 years, which equates to a multi-year drought every 18 years on average, or a 5 percent chance of a drought in any given year. The most recent drought lasted from 2012 to 2017 and resulted in a declared state of emergency. • 16 USDA Disaster Designations due to drought have been made in the last 9 years. 899
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• 281 reports of impacts related to drought were made within Stanislaus County between, 2000 and 2020.
• Between 2007-2014 a total of $90,695 crop indemnity claims was paid due to crop losses for a total of 1177.7 acres due to drought impacts; this also equals to an annualized crop loss of $11,337 due to drought impacts.
• Climate change projections show that extreme prolonged drought is likely to continue and will exacerbate existing water supply challenges.
• Related Hazards – Extreme Heat, Wildfire, Agricultural Pest Infestation and Disease Table 4-24 Hazard Risk Summary – Drought
Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Extensive Likely Critical High Yes
City of Ceres Extensive Likely Critical High Yes
City of Hughson Extensive Likely Critical Medium Yes
City of Modesto Extensive Likely Negligible Low No
City of Newman Extensive Likely Critical High No
City of Oakdale Extensive Likely Critical High Yes
City of Patterson Extensive Likely Critical High Yes
City of Riverbank Extensive Likely Critical High Yes
City of Turlock Extensive Likely Critical High Yes
City of Waterford Extensive Likely Critical High Yes
County Office of Education Extensive Likely Critical Low No

4.3.6 Earthquake
Hazard/Problem Definition
An earthquake is caused by a sudden slip on a fault. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up and the rocks slip suddenly, releasing energy in waves that travel through the earth’s crust and cause the shaking that is felt during an earthquake. The amount of energy released during an earthquake is usually expressed as a magnitude and is measured directly from the earthquake as recorded on seismographs. The magnitude of earthquakes is usually measured using the Richter Scale; a logarithmic scale calculated from the amplitude of the largest seismic wave recorded for the earthquake.

Another measure of earthquake severity is intensity. Intensity is an expression of the amount of shaking at any given location on the ground surface. Seismic shaking is typically the greatest cause of damage to structures during earthquakes. Seismologists have developed the Mercalli scale to quantify the shaking intensity of an earthquake’s effects, which is measured by how an earthquake is felt by humans and the damage to buildings.

Earthquakes can cause structural damage, injury, and loss of life, as well as damage to infrastructure networks such as water, power, gas, communication, and transportation lines. Other damage-causing effects of earthquakes are surface rupture, fissuring, settlement, and permanent horizontal and vertical shifting of the ground. Secondary impacts can include landslides, seiches, liquefaction, and dam failure.

Liquefaction occurs when ground shaking causes the mechanical properties of some fine-grained, saturated soils to liquefy and act as a fluid (liquefaction). It is the result of a sudden loss of soil strength due to a rapid increase in soil pore water pressures caused by ground shaking, in areas of shallow groundwater (within 10’ of surface or less). Liquefaction that produces surface effects generally occurs in the upper 40 to 50 feet of the soil column, although the phenomenon can occur deeper than 100 feet. The duration of ground shaking is also an important factor in causing liquefaction to occur. The larger the earthquake magnitude, and the longer the duration of strong ground shaking, the greater the potential there is for liquefaction to occur.
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In populated areas, the greatest potential for loss of life and property damage can come as a result of ground shaking from a nearby earthquake. The degree of damage depends on many interrelated factors.

Among these are the moment magnitude, focal depth, distance from the causative fault, duration of shaking, type of surface deposits or bedrock, presence of high ground water, topography, and finally, the design, type, and quality of building construction.

Geographic Area
Extensive – There are several faults known to exist within Stanislaus County. In the extreme eastern parts of the County, the Bear Mountain and Melones faults are found, though both are believed to have been inactive for the past 150 million years. Other faults are located in the western part of the County and consist of the Ortigalita Fault Zone, the Great Valley Thrust Fault System, and the San Joaquin Thrust Fault System. The Ortigalita Fault extends into Stanislaus County approximately 7 miles and is designated as an Alquist-Priolo Earthquake Fault Zone. This fault has not been active in historic times; however, there is no guarantee that it will never become active again. The nearest faults of major significance are the San Andreas to the west of Stanislaus County, a distance of approximately 25 miles from the County line; the Hayward and Calaveras faults to the northwest; the White Wolf, Garlock, and Sierra Nevada faults to the south; and the Bear Mountain Fault Zone about 5 miles east of and parallel to the eastern border of Merced County. These faults have been and will continue to be the principal source of seismic activity affecting the County of Stanislaus.

There have been no records of major seismic activity originating in the County, with most epicenters in the County being below a magnitude 4.0. However, the County has been impacted by earthquakes originating elsewhere. There is documented evidence of seven earthquakes that shook the area, those of 1872, 1906, 1952, 1966, 1984, and 1989, and more recently in 2021 when residents felt the 6.0 magnitude earthquake centered in the Little Antelope Valley along the California/Nevada border (Gerike 2021). Minor damage has been recorded throughout the County from earthquakes with epicenters in surrounding areas, though major damage occurred from the 1906 Los Banos earthquake.

The San Andreas Fault occurs where the North American and Pacific plates come together and grind in a side-by-side motion relative to each other. Another large known fault, the White Wolf fault, is located to the south near Arvin and Bakersfield in Kern County and produced a severe M 7.7 earthquake in 1952. Figure 4-11 below shows the known faults and potential for ground shaking resulting from earthquakes in and near Stanislaus County, based on USGS probabilistic ground shaking with a 2% in 50-year occurrence (AKA 2500-year probabilistic ground shaking).
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Figure 4-11 Stanislaus County Earthquake Ground Shaking Potential and Nearby Faults Earthquakes can occur at any time of the day or night and any time of the year. Earthquakes are particularly dangerous due to their rapid onset, generally without warning. Aftershocks can occur for days, weeks, and even months following a major earthquake. This additional damage to structures already weakened by the main earthquake increases the danger to rescue and recovery personnel.

Extent (Magnitude/Severity)
Catastrophic – For extent, the severity of an earthquake, or the amount of energy released during an earthquake is usually expressed in terms of intensity or magnitude as described further below.

Intensity – Intensity represents the observed effects of ground shaking at any specified location and earthquake shaking decreases with distance from the earthquake epicenter. Intensity is an expression of the amount of shaking at any given location on the ground surface based on felt or observed effects.

Seismic shaking is typically the greatest cause of losses to structures during earthquakes. Intensity is measured with the Modified Mercalli Intensity (MMI) scale. The intensity of ground shaking at a particular site or structure is a function of many factors including: 1) earthquake magnitude, 2) distance from the epicenter, 3) duration of strong ground motion, 4) local geologic conditions (soil type and topography), and 5) the fundamental period of the structure. A brief description of those factors is presented below. The MMI scale is summarized in Table 4-25, along with the effects associated with the MMI scale. Damage typically occurs in MMI of scale VII or above.
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Table 4-25 Earthquake Magnitude and Intensity Measurements and Intensity Characteristics Magnitude Mercalli
Intensity Effects Frequency
Less than

2.0 I Microearthquakes, not felt or rarely felt; recorded by seismographs. Continual

2.0-2.9 I to II Felt slightly by some people; damages to buildings. Over 1M per year

3.0-3.9 II to IV Often felt by people; rarely causes damage; shaking of indoor objects noticeable.

Over
100,000 per
year

4.0-4.9 IV to VI Noticeable shaking of indoor objects and rattling noises; felt by most people in the affected area; slightly felt outside; generally, no to minimal damage.
10K to 15K
per year

5.0-5.9 VI to VIII Can cause damage of varying severity to poorly constructed buildings; at most, none to slight damage to all other buildings. Felt by everyone. 1K to 1,500
per year

6.0-6.9 VII to X Damage to a moderate number of well-built structures in populated areas; earthquake-resistant structures survive with slight to moderate damage; poorly designed structures receive moderate to severe damage; felt in wider areas; up to hundreds of miles/kilometers from the epicenter; strong to violent shaking in epicentral area. 100 to 150
per year

7.0-7.9 VIII< Causes damage to most buildings, some to partially or completely collapse or receive severe damage; well-designed structures are likely to receive damage; felt across great distances with major damage mostly limited to 250 km from epicenter.
10 to 20 per
year

8.0-8.9 VIII< Major damage to buildings, structures likely to be destroyed; will cause moderate to heavy damage to sturdy or earthquake-resistant buildings; damaging in large areas; felt in extremely large regions.

One per year

9.0 and
Greater
VIII< At or near total destruction – severe damage or collapse to all buildings; heavy damage and shaking extends to distant locations; permanent changes in ground topography.

One per 10-
50 years
Source: USGS
Magnitude – Magnitude represents the amount of seismic energy released at the hypocenter of an earthquake. It is based on the amplitude of the earthquake waves recorded. Seismologists have developed several magnitude scales; one of the first was the Richter Scale, developed in 1932 by the late Dr. Charles F. Richter of the California Institute of Technology. The Richter Scale is numeric and has a logarithmic relationship between scale factors, so that a difference of one scale number represents a tenfold increase in measured amplitude, which in turn corresponds to an approximate 31x energy release difference when compared to the next whole number value. The Moment Magnitude scale (Mw, or M), which is a measurement of energy released by the movement of a fault and is the modern method used by seismologists to measure earthquakes. Overall, as the amount of energy released by an earthquake increases, the potential for ground shaking impacts also increases.

Distance from Epicenter – Earthquake energy generally dissipates (or attenuates) with distance from a fault. Over long distances, this loss of energy can be significant, resulting in a significant decrease in ground shaking with increased distance from the epicenter.

Duration of Strong Shaking – The duration of the strong ground shaking constitutes a major role in determining the amount of structural damage and the potential for ground failure that can result from an earthquake. Larger magnitude earthquakes have longer durations than smaller earthquakes.

Local Geologic Conditions – The geologic and soil conditions at a particular site have the potential to substantially increase the effects of ground shaking. The thickness, density, and consistency of the soil, as well as shallow ground water levels, have the potential to amplify the effects of ground shaking depending on the characteristics of the earthquake. In general, the presence of unconsolidated soils above the bedrock surface can amplify the ground shaking caused by an earthquake. 903
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Fundamental Periods – Every structure has its own fundamental period or natural vibration. If the vibration of ground shaking coincides with the natural vibration period of a structure, damage to the structure can be greatly increased. The extent of damage suffered during an earthquake can also depend on non-geologic factors. The type of building and its structural integrity will influence the severity of the damage suffered.

Generally, small, well-constructed, one- and two-story wood and steel frame buildings have performed well in earthquakes because of their light weight and flexibility. Reinforced concrete structures will also usually perform well. Buildings constructed from non-flexible materials, such as unreinforced brick and concrete, hollow concrete block, clay tile, or adobe, are more vulnerable to earthquake damage.

Effects of Ground Shaking – The primary effect of ground shaking is the damage or destruction of buildings, infrastructure, and possible injury or loss of life. Building damage can range from minor cracking of plaster to total collapse. Disruption of infrastructure facilities can include damage to utilities, pipelines, roads, and bridges. Ruptured gas and water lines can result in fire and produce scour/inundation damage, respectively, to structures, as can fire from other causes, such as electrical damages. Secondary effects can include geologic impacts such as co-seismic fault movement along nearby faults, seismically induced slope instability, liquefaction, lateral spreading, and other forms of ground failure and seismic response.

These secondary effects were demonstrated in Oceano by the San Simeon 2003 earthquake.

Figure 4-12 depicts the epicenters of the historic earthquakes that have occurred in Stanislaus County from 1855 through 2021. As shown in the figure, most of the epicenters have occurred along the San Andreas and Hayward faults to the west of the Planning Area.
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Figure 4-12 Stanislaus County Historic Earthquake Epicenters: 1855 – 2021 905
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Past Occurrences
Based on the County’s 2017 LHMP, since 1930, one earthquake epicenter of a magnitude greater than 4.0 on the Richter Scale was recorded within Stanislaus County. On June 27, 1986, an earthquake with a magnitude of 3.7 on the Richter Scale occurred with an epicenter several miles west of Crows Landing.

Other than those, there have not been any damaging earthquakes greater than M 6.0 recorded in Stanislaus County in over 200 years and the County has not been included in any federal disaster declarations involving earthquakes, though several have been very close.

The most recent large earthquake near Stanislaus County was 16 miles east north-east of King City at a magnitude of 5.3 on October 20, 2012. Several aftershocks followed the main earthquake, including a 3.1 aftershock. This quake was preceded by an earthquake on October 31, 2007 (M 5.5) in the East Foothills of Santa Clara County, a 5.1 magnitude earthquake in 1990 near Ridgemark, California and two earthquakes along the Watsonville east quadrangle, between the Santa Cruz and Santa Clara County boundaries, located approximately 25 miles west of Stanislaus County. There was a low level of ground shaking reported.

Major earthquakes have occurred near Stanislaus County and resulted in ground shaking felt in the County.

The Fort Tejon earthquake in 1857 of M 7.9 was one of the greatest earthquakes ever recorded in the United States and the largest in California. It left an extensive surface rupture scar over 215 miles in length along the San Andreas Fault. The epicenter is now thought to have been located near Cholame, approximately 134 miles southwest of Stanislaus. During the Fort Tejon earthquake, strong shaking lasted from one to three minutes. As a result of the shaking, the flow of the Kern River was turned upstream, and water ran four feet deep over its banks. The waters of Tulare Lake were thrown upon its shores, stranding fish miles from the original lakebed. Property loss was heavy at Fort Tejon, one of the only settlements at the time, an Army post in south-central Kern County about four miles from the San Andreas Fault. In 1857, two buildings were declared unsafe, three others were damaged extensively but were habitable, and still others sustained moderate damage. One person was killed in the collapse of an adobe house at Gorman.

Figure 4-13 below displays the common areas damaged by earthquakes based on historic evidence dating back to the year 1800. The occurrences are color-coded by damaging shaking intensity across California, and Stanislaus County is enclosed within a red circle. The figure shows that, per the MMI scale noting occurrences equal to or greater than an Intensity of VII, the County has experienced 1 to 3 earthquake events of this kind, mostly affecting the far western and southwestern portions of the County. 906
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Figure 4-13 Areas Damaged by Earthquakes from 1800 to 2017 Source: California SHMP, 2018; California Geologic Survey Probability of Future Occurrences
Occasional – It is estimated that major earthquakes (ranging from a magnitude of 7 to 7.9) occur in California one out of every 10 years. However, strong earthquakes (from magnitudes 6 to 6.9) strike the State about once every two to three years. A strong earthquake can cause major damage depending on the epicenter’s location with regards to populated areas, and can lead to billions of dollars in disasters, deaths, injuries, and disruptions in services and communities’ way of life. Moderate earthquakes (around 907
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magnitudes of 5.5) can occur three to four times a year in the State. For Stanislaus County, as previously mentioned there is documented evidence of seven earthquakes that shook the area, (1872, 1906, 1952, 1966, 1984, and 1989, and more recently in 2021) over a 150-year period equating to a 4.6% probability of future occurrence.

Along the San Andreas Fault, segments exist where no large earthquakes have occurred for long intervals of time. These areas accumulate potential energy and provide clues as to where the next earthquake may occur and when. Scientists term these segments “seismic gaps” and, in general, have been successful in forecasting the time when some of the seismic gaps will produce large earthquakes. Geologic studies show that over the past 1,400 to 1,500 years, large earthquakes have occurred at about 150-year intervals on the southern San Andreas Fault. As the last large earthquake on the southern San Andreas was the Fort Tejon earthquake in 1857, that section of the fault is considered a likely location for an earthquake within the next few decades (USGS 1997).

Climate Change Considerations
Climate change is not expected to directly affect earthquake frequency or intensity.

Vulnerability Assessment
Earthquake loss estimation for the 2021 MJHMP update utilized FEMA’s Hazus-MH 5.0 natural hazard loss estimation software. Hazus is a GIS-based, standardized, nationally applicable multi-hazard loss estimation methodology and software. Local, state, and federal government officials use Hazus for preparedness, emergency response, and mitigation planning. A Level 1 Hazus analysis was performed, which estimates damage based on an inventory database compiled at a national level aggregated to Census Tracts. As with any model there are uncertainties and the results should be considered approximate for planning purposes.

To evaluate potential losses associated with earthquake activity in the Planning Area, two Hazus scenarios were run for the Stanislaus County, including a Hazus 2,500-year probabilistic scenario and a Magnitude

6.9 – Great Valley ShakeMap Scenario.

The 2,500-year scenario considers multiple faults in the region. The methodology utilizes probabilistic seismic hazard contour maps developed by the USGS for the 2018 update of the National Seismic Hazard Maps that are included with Hazus-MH. The USGS maps provide estimates of potential ground acceleration and spectral acceleration at periods of 0.3 second and 1.0 second, respectively. The 2,500-year return period analyzes ground shaking estimates from the various seismic sources in the area with a 2 percent probability of being exceeded in 50 years. The International Building Code (IBC) uses this level of ground shaking for building design in seismic areas.

The Magnitude 6.9 Great Valley ShakeMap Scenario is a deterministic earthquake analysis that was modeled using Hazus for Stanislaus County. A deterministic scenario predicts the outcome of a specific earthquake event. This deterministic scenario used USGS provided ShakeMap datasets to model what a Magnitude 6.9 earthquake of the Great Valley Fault Thrust System would generate in terms of damages and losses for the chosen area of interest (i.e. Stanislaus County). The datasets used to import into Hazus

5.0 for the scenario included four USGS provided data layers in geospatial format: peak ground velocity, peak ground acceleration, peak spectral acceleration for 0.3 seconds (0.3 % g, or gravitational velocity), and peak ground acceleration for 1.0 seconds (1.0 % g).

Hazus estimates the number of people displaced, the number of buildings and facilities/infrastructure damaged, the number of casualties, and the damage to transportation systems and utilities. Results produced by Hazus are reported at the census tract level. These results and the estimated impacts are summarized below in the vulnerability assessment.

General Property
Unreinforced Masonry Building (URM)s – Unreinforced masonry building type structures consist of buildings made of unreinforced concrete and brick, hollow concrete blocks, clay tiles, and adobe. Buildings constructed of these materials are heavy and brittle, and typically provide little earthquake resistance. In small earthquakes, unreinforced buildings can crack, and in strong earthquakes, they have a tendency to collapse. These types of structures pose the greatest structural risk to life and safety of all general building types. Due to the public safety risks that are posed by unreinforced masonry (URM) buildings, the California legislature passed Senate Bill 547 (Government Code Section 8875 et seq.). This legislation went into effect 908
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January 1, 1987, and required all cities and counties located in Seismic Zone 4 to conduct an inventory of potentially hazardous structures, including unreinforced masonry buildings.

Hazus estimates the number of buildings that will be damaged during a modeled earthquake, and these estimates are provided in the figures and tables below. According to Hazus results, under the 2,500-year probabilistic scenario, the total building-related losses were $6,162.70 (millions of dollars). By far, the largest loss was sustained by the residential occupancies which made up over 58% of the total loss. Under the Great Valley ShakeMap Scenario, total building-related losses were $1,395.79 (millions of dollars). By far, the largest loss was sustained by the residential occupancies, which made up over 64% of the total loss. Figure 4-14 and Figure 4-15 below provide summaries of the losses associated with the building damage under the two scenarios. The 2,500-Year Probabilistic Scenario is expected to result in more economic losses than the Great Valley ShakeMap Scenario.

Figure 4-14 Earthquake Losses by Loss Type and Occupancy Type – 2,500 Probabilistic Scenario (in Millions of Dollars)
Figure 4-15 Earthquake Losses by Loss Type and Occupancy Type – Great Valley ShakeMap Scenario (in Millions of Dollars)
Table 4-26 and Table 4-27 show the expected building damage categorized by both building type and the degree of the expected damage. For each scenario, the majority of structures will either not be damaged or suffer slight to moderate damage. The 2,500-Year Probabilistic Scenario is expected to produce more severe building damage than the Great Valley ShakeMap Scenario. 909
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Table 4-26 Expected Building Damage by Occupancy – 2,500-Year Probabilistic Scenario None Slight Moderate Extensive Complete
Count (%) County (%) Count (%) Count (%) Count (%)
Agriculture 295.23 0.44 250.84 0.40 213.49 0.77 97.34 1.50 48.10 1.69 Commercial 1,920.73 2.85 1,685.76 2.70 1,954.33 7.01 1,027.82 15.80 441.36 15.54 Education 100.22 0.15 77.36 0.12 61.47 0.22 26.03 0.40 9.92 0.35 Government 43.58 0.06 35.78 0.06 38.35 0.14 22.58 0.35 10.70 0.38 Industrial 464.15 0.69 428.20 0.69 539.56 1.94 304.41 4.68 143.67 5.06 Other
Residential
2,592.67 3.85 2,904.41 4.65 3,528.24 12.65 3,326.69 51.14 1,742.98 61.38 Religion 184.35 0.27 153.22 0.25 142.22 0.51 74.63 1.15 32.58 1.15 Single
Family
61,677.08 91.67 56,903.75 91.1
3 21,402.81 76.77 1,625.08 24.98 410.27 14.45
Total 67,278 62,439 27,880 6,505 2,840
Source: Hazus-MH 5.0
Table 4-27 Expected Building Damage by Occupancy – Great Valley ShakeMap Scenario None Slight Moderate Extensive Complete
Count (%) County (%) Count (%) Count (%) Count (%)
Agriculture 615.58 0.51 165.73 0.47 94.05 1.01 24.63 2.06 5.00 2.54 Commercial 4,762.70 3.93 1,272.54 3.64 784.44 8.45 182.14 15.21 28.17 14.32 Education 199.10 0.16 47.93 0.14 22.62 0.24 4.66 0.39 0.68 0.34 Government 102.69 0.08 26.82 0.08 16.53 0.18 4.25 0.35 0.71 0.36 Industrial 1,238.71 1.02 344.33 0.98 231.73 2.50 56.51 4.72 8.72 4.43 Other
Residential
8,163.63 6.73 3,073.08 8.79 2,158.38 23.26 624.56 52.16 75.35 38.30 Religion 413.11 0.34 103.90 0.30 54.79 0.59 12.99 1.08 2.20 1.12 Single
Family
105,808.23 87.23 29,928.66 85.60 5,918.50 63.77 287.68 24.02 75.92 38.59 Total 121,304 34,963 9,281 1,197 197
Source: Hazus-MH 5.0
Figure 4-16 and Figure 4-17 below display the census tracts within the County that were analyzed in the two scenarios, color-coded by the amount of total building loss each tract experienced. 910
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Figure 4-16 Stanislaus County Hazus 2,500-Year Probabilistic Scenario Total Building Loss (in Thousands of Dollars)
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Figure 4-17 Stanislaus County Great Valley ShakeMap Scenario Total Building Loss (in Thousands of Dollars)
People
Loss of utility service would have major impacts on the people of the County. The following tables indicate the number of projected households that would experience power and water loss, and the number of days the loss would last. The 2,500-Year Probabilistic Scenario is expected to cause a longer delay in the recovery of potable water and electric power systems as well as cause more people to be without potable water or electric power compared to the Great Valley ShakeMap Scenario. 912
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Table 4-28 Expected Potable Water and Electric Power System Performance – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
Table 4-29 Expected Potable Water and Electric Power System Performance – Great Valley ShakeMap Scenario
Total Number
of Households
Number of Households without Service
At Day 1 At Day 3 At Day 7 At Day 30 At Day 90
Potable
Water 165,180
1,676 246 0 0 0
Electric
Power 0 0 0 0 0
Source: Hazus-MH 5.0
Sheltering is another concern during an earthquake – people may be displaced from their homes due to the earthquake, and those displaced people may need accommodations in temporary public shelters. Table 4-30 shows projected total displacement and projected shelter needs for each scenario. The 2,500-Year Probabilistic Scenario is expected to result in more displaced households and also people seeking shelter than the Great Valley ShakeMap Scenario.

Table 4-30 Shelter Requirements
2,500-Year Probabilistic Scenario Great Valley ShakeMap Scenario Total Population 514,453 Total Population 514,453
Total Displaced Households 2,533 Total Displaced Households 351 Total Seeking Shelter 2,020 Total Seeking Shelter 293
Source: Hazus-MH 5.0
The Hazus models potential casualty numbers based on magnitude and time of occurrence for the earthquake. Casualties are broken out by occupancy class, and severity is separated into one of four categories.
• Level 1 – Injuries will require medical attention but hospitalization not needed • Level 2 – Injuries will require hospitalization but are not considered life-threatening • Level 3 – Injuries will require hospitalization and can become life-threatening if not promptly treated • Level 4 – Victims are killed by the earthquake
Hazus estimates are provided for three times of day – 2 AM, 2 PM, and 5 PM. These times represent the periods of the day that different sectors of the community are at their peak occupancy loads. The 2 AM estimate considers that the residential occupancy load is maximum, the 2 PM estimate considers that the educational, commercial, and industrial sector loads are maximum, and 5 PM represents peak commute time. The following tables show casualty estimates for the different times of day for each scenario. The 2,500-Year Probabilistic Scenario is expected to result in more casualties and also more severe casualties than the Great Valley ShakeMap Scenario.

Total Number
of Households
Number of Households without Service
At Day 1 At Day 3 At Day 7 At Day 30 At Day 90
Potable
Water 165,180
102,364 98,831 91,064 26,111 0
Electric
Power 82,462 46,217 16,462 2,782 127
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Table 4-31 Casualty Estimates – 2,500-Year Probabilistic Scenario Level 1 Level 2 Level 3 Level 4
2 AM
Commercial 24.58 6.64 1.03 2.04
Commuting 0.19 0.24 0.42 0.08
Educational 0.00 0.00 0.00 0.00
Hotels 0.00 0.00 0.00 0.00
Industrial 40.54 10.72 1.57 3.07
Other- Residential 427.20 97.83 9.29 17.05
Single Family 369.73 47.32 2.32 4.12
Total 862 163 15 26
2 PM
Commercial 1,512.41 408.03 63.78 124.99
Commuting 1.71 2.20 3.82 0.73
Educational 575.58 157.52 25.43 49.77
Hotels 0.00 0.00 0.00 0.00
Industrial 298.45 78.75 11.56 22.44
Other- Residential 97.87 22.49 2.20 3.98
Single Family 83.61 10.88 0.61 0.94
Total 2,570 680 107 203
5 PM
Commercial 1,107.33 298.11 46.77 90.57
Commuting 26.95 34.67 60.07 11.55
Educational 48.06 13.10 2.11 4.13
Hotels 0.00 0.00 0.00 0.00
Industrial 186.53 49.22 7.23 14.02
Other- Residential 156.48 35.94 3.51 6.36
Single Family 141.62 18.43 1.03 1.58
Total 1,667 449 121 128
Source: Hazus-MH 5.0
Table 4-32 Casualty Estimates – Great Valley ShakeMap Scenario Level 1 Level 2 Level 3 Level 4
2 AM
Commercial 3.32 0.64 0.08 0.16
Commuting 0.01 0.02 0.03 0.01
Educational 0.00 0.00 0.00 0.00
Hotels 0.00 0.00 0.00 0.00
Industrial 5.83 1.13 0.14 0.26
Other- Residential 54.09 7.72 0.47 0.86
Single Family 108.89 9.75 0.29 0.48
Total 172 19 1 2
2 PM
Commercial 205.12 39.49 4.93 9.61
Commuting 0.12 0.16 0.27 0.05
Educational 78.53 14.87 1.87 3.64
Hotels 0.00 0.00 0.00 0.00
Industrial 42.81 8.33 1.00 1.94
Other- Residential 12.10 1.72 0.11 0.19
Single Family 23.97 2.21 0.08 0.11
Total 363 67 8 16
5 PM
Commercial 151.85 29.45 3.71 7.16
Commuting 1.82 2.44 4.11 0.80
Educational 6.15 1.13 0.14 0.27
Hotels 0.00 0.00 0.00 0.00
Industrial 26.76 5.21 0.63 1.21
Other- Residential 19.76 2.85 0.18 0.32
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Level 1 Level 2 Level 3 Level 4
Single Family 40.90 3.79 0.14 0.19
Total 247 45 9 10
Source: Hazus-MH 5.0
Social Vulnerability
Populations most vulnerable to earthquake hazards would be those that rely on specific services or electrical power, which may not be available during or after an earthquake, or those which are homeless, would have a difficult time evacuating due to age or disability, cannot communicate easily due to speaking English less than well, for example.

Government Services
Damage to government facilities and infrastructure from a major earthquake would likely interrupt or delay the ability of local governments to delivery of services and could require temporary relocation of some operations. Regulatory waivers may be needed locally. Fulfillment of some contracts may be difficult.

Responders will initially experience similar impacts as the general public. However, in the aftermath of a major earthquake responders would likely be put in very hazardous circumstances as they attempt to save lives, protect property, and deliver essential services. Public confidence in government may be challenged by the public if planning, response, and recovery are not timely and effective.

Economy
Depending on its location and magnitude, an earthquake could have a devastating impact on the County’s economy. Impacts would be related to debris cleanup and management, building and infrastructure damage, and losses related to business and infrastructure interruption. Hazus estimates economic impacts for earthquakes modeled. Losses estimated include building-related losses, and transportation and utility lifeline losses. The model estimates loss over a 15-year span after the incident.

Building losses are broken into two categories – direct building losses and business interruption losses.

The direct building losses are the estimated costs to repair or replace the damage caused to the building and its contents. Business interruption losses are the losses associated with the inability to operate a business because of the damage sustained during the earthquake. Business interruption losses also include the temporary living expenses for those people displaced from their homes because of the earthquake. Table 4-33 shows the economic losses under the two scenarios broken down by loss categories and occupancy types. The 2,500-year probabilistic scenario is expected to cause more economic losses.

Table 4-33 Economic Losses (Millions of Dollars)
2,500-Year Probabilistic Scenario
Category Single Family Other Residential Commercial Industrial Others Total Income Losses $208.58 $82.39 $485.06 $30.09 $48.26 $854.37 Capital Stock
Losses
$2,575.12 $678.65 $1,236.6 $500.42 $317.54 $53,08.33
Total $2,783.70 $761.03 $1,721.65 $530.51 $365.80 $6,162.70 Great Valley ShakeMap Scenario
Category Single Family Other Residential Commercial Industrial Others Total Income Losses $53.69 $16.76 $95.65 $7.21 $9.78 $183.09
Capital Stock
Losses
$696.22 $130.29 $224.82 $97.65 $63.72 $1,212.7
Total $749.92 $147.05 $320.47 $104.86 $73.49 $1,395.79
Source: Hazus-MH 5.0
The total building-related losses under the 2,500-Year Probabilistic Scenario were $6.16 billion. Fourteen percent of the estimated losses were related to the business interruption of the region. By far, the largest loss was sustained by the residential occupancies, which made up over 58% of the total loss. 915
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The total building-related losses under the Great Valley ShakeMap Scenario were $1.4 billion. Thirteen percent of the estimated losses were related to the business interruption of the region. By far, the largest loss was sustained by the residential occupancies, which made up over 64% of the total loss. The 2,500- Year Probabilistic Scenario is expected to result in more economic losses than the Great Valley ShakeMap Scenario. The economic loss associated with the disruption of lifeline systems, specifically transportation and utility lifelines are shown in Table 4-34 and Table 4-35.

Table 4-34 Lifeline System Losses for 2,500-Year Probabilistic Scenario – Transportation and Utility (Millions of Dollars)
2,500-Year Probabilistic Scenario
System Inventory Value Economic Loss
Highway $3,898.68 $77.03
Railways $1,052.92 $30.62
Light Rail $0 $0
Bus $7.32 $2.58
Ferry $0 $0
Port $0 $0
Airport $158.47 $0
Potable Water $166.82 $19.9
Wastewater $1,408.98 $419.8
Natural Gas $210.59 $3.43
Oil Systems $0 $0
Electrical Power $4,800.8 $1,338.7
Communication $2.24 $0.59
Source: Hazus-MH 5.0
Table 4-35 Lifeline System Losses for Great Valley ShakeMap Scenario – Transportation and Utility (Millions of Dollars)
Great Valley ShakeMap Scenario
System Inventory Value Economic Loss
Highway $3,898.68 $15.2
Railways $1,052.92 $4.28
Light Rail $0 $0
Bus $7.32 $0.79
Ferry $0 $0
Port $0 $0
Airport $158.47 $3.48
Potable Water $166.82 $2.53
Wastewater $1,408.98 $126.76
Natural Gas $210.59 $0.44
Oil Systems $0 $0
Electrical Power $4,800.8 $312.97
Communication $2.24 $0.2
Source: Hazus-MH 5.0
The 2,500-Year Probabilistic Scenario is also expected to result in more lifeline system losses than the Great Valley ShakeMap Scenario.

Critical Facilities and Infrastructure
Hazus breaks critical facilities into two groups: essential facilities and high potential loss (HPL) facilities.

Essential facilities include hospitals, medical clinics, schools, fire stations, police stations and emergency operations facilities. HPL facilities include dams, levees, military installations, nuclear power plants and hazardous material sites. There are 12 hospitals in Stanislaus with a total bed capacity of 1,584 beds. There are also 231 schools, 51 fire stations, 14 police stations and three emergency operation facilities. The inventory also includes 48 hazardous material sites.
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On the day of the earthquake in the 2,500-Year Probabilistic Scenario, the model estimates that 729 hospital beds (46%) would be available for use by patients already in the hospital and those injured by the earthquake. After one week, 72% of the beds would be back in service. By 30 days, 92% will be operational.

The expected damages from the earthquake event are provided in Table 4-36.

Table 4-36 Expected Damage to Essential Facilities – 2,500-Year Probabilistic Scenario Source: Hazus-MH 5.0
On the day of the earthquake for the Great Valley ShakeMap Scenario, the model estimates that 1,248 hospital beds (79%) would be available for use by patients already in the hospital and those injured by the earthquake. After one week, 93% of the beds would be back in service. By 30 days, 99% will be operational.

The expected damages from the earthquake event are provided in Table 4-37.

Table 4-37 Expected Damage to Essential Facilities – Great Valley ShakeMap Scenario Source: Hazus-MH 5.0
Within Hazus, the lifeline inventory is divided between transportation and utility lifeline systems. There are seven transportation systems that include highways, railways, light rail, bus, ports, ferry, and airports. There are also six utility systems that include potable water, wastewater, natural gas, crude & refined oil, electric power, and communications. The transportation systems inventory and expected damages from the earthquake, in terms of number of structures and locations affected, are provided in Table 4-38 and Table 4-39 for the two scenarios, while losses in millions of dollars are summarized in Table 4-40 and Table 4-41. 917
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The total value of the lifeline inventory is over $11.7 billion. This inventory includes over 323.7 miles of highways, 380 bridges, and 8,405.9 miles of pipes.

Table 4-38 Expected Damage to the Transportation Systems – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
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Table 4-39 Expected Damage to the Transportation Systems – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
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Table 4-40 Transportation System Economic Losses (Millions of dollars) – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
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Table 4-41 Transportation System Economic Losses (Millions of dollars) – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
The replacement value of the transportation and utility lifeline systems is estimated to be $5.14 billion and $6.59 billion, respectively. The expected utility system facility damages in terms of total structures or systems affected, along with the inventory of this dataset, are summarized in Table 4-42 and Table 4-43 for the two scenarios respectively. Economic losses in millions of dollars are found in Table 4-44 and Table 4-45. Site specific expected utility system pipeline damages (including their inventory) are included in Table 4-46 and Table 4-47, while the potable water and electric power system performance limitations, damages, and inventory will be in Table 4-48 and Table 4-49.
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Table 4-42 Expected Utility System Facility Inventory and Damages – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
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Table 4-43 Expected Utility System Facility Inventory and Damages – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
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Table 4-44 Utility System Economic Losses in Millions of Dollars – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
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Table 4-45 Utility System Economic Losses in Millions of Dollars – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
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Table 4-46 Expected Utility System Pipeline Damage (Site Specific) – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
Table 4-47 Expected Utility System Pipeline Damage (Site Specific) – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
Table 4-48 Expected Potable Water and Electric Power System Performance – 2,500-Year Probabilistic Scenario
Source: Hazus-MH 5.0
Table 4-49 Expected Potable Water and Electric Power System Performance – Great Valley ShakeMap Scenario
Source: Hazus-MH 5.0
In summary, a major earthquake would result in serious impacts on critical infrastructure. Hazus estimates impacts to critical facilities including hospitals, schools, EOCs, police stations and fire stations. These impact estimates are shown in Table 4-50 and Table 4-51. As shown the two tables, the 2,500-Year Probabilistic Scenario is expected to cause more damage and also more severe damage to critical facilities, as well as result in delays for the critical facilities to recover than the Great Valley ShakeMap Scenario. 926
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Table 4-50 Expected Damage to Critical Facilities – 2,500-Year Probabilistic Scenario Classification Total Number of Facilities
At Least Moderate
Damage > 50%
Complete Damage
> 50%
With Functionality
> 50% on Day 1
Hospitals 12 2 0 10
Schools 231 28 0 108
EOCs 3 0 0 3
Police Stations 14 4 0 6
Fire Stations 51 9 0 18
Total 311 43 0 145
Source: Hazus-MH 5.0
Table 4-51 Expected Damage to Critical Facilities – Great Valley ShakeMap Scenario Classification Total Number of Facilities
At Least Moderate
Damage > 50%
Complete Damage
> 50%
With Functionality
> 50% on Day 1
Hospitals 12 0 0 12
Schools 231 1 0 205
EOCs 3 0 0 3
Police Stations 14 0 0 10
Fire Stations 51 0 0 40
Total 311 1 0 270
Source: Hazus-MH 5.0
Historic, Cultural, and Natural Resources
Earthquake effects on the environment, natural resources, and historic and cultural assets could be very destructive depending on the type of seismic activity experienced and secondary/cascading effects from an event (e.g., wildfire). The biggest impact would likely be on older properties such as wooden or masonry buildings, though reinforced masonry structures would be much more resilient during earthquakes.

Future Development
Future development in the County is not anticipated to significantly affect vulnerability to earthquakes when designed according to modern building codes. However, future development will result in a slight increase in exposure of the population, building stock, and related infrastructure to earthquakes.

Risk Summary
• Stanislaus County is located in a geologically complex and seismically active region, albeit less so than other areas of California. There are numerous active and potentially active faults in close proximity to the County. The County does not have a history of significant damaging earthquakes. • The overall significance of earthquakes is Medium but ranked High for communities on the western and southern sides of the County including cities of Patterson and Newman and in the more densely populated cities including Cities of Modesto and Oakdale. • A moderate earthquake occurring in or near Stanislaus County could result in deaths, casualties, property damage, agricultural and environmental damage, and disruption of normal government and community services and activities.
• The location of the epicenter as well as the time of day and season of the year would have a profound effect on the number of deaths and casualties, as well as property damage. • The hazard of earthquakes varies from place to place, dependent upon the regional and local geology. • Effects on people – Hazus 2,500-year probabilistic scenario modeling results in estimates of 178 to 787 people needing hospitalization and between 26 to 203 deaths depending on the time of day the earthquake hits; Hazus Great Valley ShakeMap Scenario modeling results in estimates of 20 to 75 people needing hospitalization and between 2 to16 deaths depending on the time of day the earthquake hits.
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• Effects on property – Hazus 2,500-year probabilistic scenario modeling indicates about 37,224 buildings will be at least moderately damaged, with approximately $6.16 billion in losses; Hazus Great Valley ShakeMap Scenario modeling indicates about 10,675 buildings will be at least moderately damaged, with approximately $1.4 billion in losses.
• Effects on economy – The total economic loss estimated under Hazus 2,500-year probabilistic scenario is $8.1 billion, which includes building and lifeline related losses based on the region's available inventory. The total economic loss estimated under Hazus Great Valley ShakeMap Scenario is $1.9 billion, which includes building and lifeline related losses based on the region's available inventory.
• Effects on critical facilities and infrastructure – Under the Hazus 2,500-year probabilistic scenario essential facility damage (police, fire, school, medical) is predicted to be low; only 729 hospital beds (46%) would be available during the earthquake. Under the Hazus Great Valley ShakeMap Scenario, essential facility damage (police, fire, school, medical) is predicted to be very low; 1,248 hospital beds (79%) would be available during the earthquake.
• Cascading and Secondary Effects – Earthquakes can cause many cascading effects such as fires, flooding, hazardous materials spills, utility disruptions, landslides, and transportation emergencies.

Ground shaking may cause tsunamis or seiche, the rhythmic sloshing of water in lakes or bays.

Table 4-52 Hazard Risk Summary – Earthquake
Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Extensive Occasional Critical Medium Yes City of Ceres Extensive Occasional Critical Medium No
City of Hughson Extensive Occasional Critical Medium No City of Modesto Extensive Occasional Critical Medium No City of Newman Extensive Occasional Critical Medium Yes City of Oakdale Extensive Occasional Limited Medium No
City of Patterson Extensive Occasional Critical Medium Yes City of Riverbank Extensive Occasional Critical Medium Yes City of Turlock Extensive Occasional Critical Medium No City of Waterford Extensive Occasional Limited Medium Yes County Office of Education Extensive Occasional Critical Medium Yes

4.3.7 Extreme Temperatures: Freeze and Extreme Heat
Hazard/ Problem Description
Extreme temperature events, both cold and hot, can have severe impacts on human health and mortality, natural ecosystems, and agriculture and other economic sectors.

Freeze
Extreme cold often accompanies a winter storm or is left in its wake. Prolonged exposure to cold can cause frostbite or hypothermia and can be life-threatening. Infants and the elderly are most susceptible.

Pipes may freeze and burst in homes or buildings that are poorly insulated or without heat. Freezing temperatures can cause significant damage to the agricultural industry.

Extreme Heat
Extreme heat events can have severe impacts on human health and mortality, natural ecosystems, the agriculture sector, and other economic sectors. According to information provided by FEMA, extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks. In other words, heat waves are periods of abnormally hot weather lasting days to weeks. Heat wave duration and the number of extreme heat events per year are common metrics used to describe extreme heat hazards.
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Heat kills by taxing the human body beyond its abilities, usually from heat stroke. In a normal year, about 175 Americans succumb to the demands of summer heat. The average annual temperature increases in California have already exceeded 1°F, with some areas exceeding 2°F (CNRA 2021). The daily maximum average temperature, an indicator of extreme temperature shifts, is expected to rise 4.4°F – 5.8°F by 2050 and 5.6°F – 8.8°F by 2100 (CNRA 2021). Heat waves that result in public health impacts, also referred to as heat-health events, are also projected to worsen. By 2050, average heat-health events are projected to last two weeks longer in the Central Valley (CNRA 2021). According to the NWS, among natural hazards, only the cold of winter—not lightning, hurricanes, tornadoes, floods, or earthquakes—takes a greater toll.

As a comparison, in the 40-year period from 1936 through 1975, nearly 20,000 people were killed in the United States by the effects of heat and solar radiation. In the heat wave of 1980, more than 1,250 people died. The 2018 California SHMP notes the 2006 heat wave led to 650 deaths in a 13-day period (Cal OES 2018) and in the past 15 years heat waves have claimed more lives in California than all other declared disaster events combined (California Climate Adaptation Strategy 2018). According to the Draft Extreme Heat Action Plan, extreme heat ranks amongst the deadliest of all climate change-driven hazards in California.

Heat disorders generally have to do with a reduction or collapse of the body’s ability to shed heat by circulatory changes and sweating or a chemical (salt) imbalance caused by too much sweating. When heat gain exceeds the level the body can remove, or when the body cannot compensate for fluids and salt lost through perspiration, the temperature of the body’s inner core begins to rise, and heat-related illness may develop. The elderly, small children, individuals who work outside, patients with chronic medical conditions, those on prescription medication therapy, and people with weight and alcohol problems are particularly susceptible to heat reactions, especially during heat waves in areas where moderate climate usually prevails. In summary, extreme heat threatens public health and safety, economic prosperity, natural systems, and communities and has disproportionate consequences on vulnerable populations.

Geographic Area
Extensive – The entire County is susceptible to extreme cold temperatures. The climate in Stanislaus County is also hot and arid, and the entire County is susceptible to extreme heat and heat waves.

Freeze
The entire county is susceptible to extreme temperatures. Unseasonable cold temperatures can have substantial impacts on crops in Stanislaus County.

Extreme Heat
The agriculturally dominated central region of the County is likely to experience the greatest impacts from large or unseasonable temperature variations. The more urbanized areas of the County may experience the urban heat island effect due to the number of impervious surfaces in those areas that absorb and keep heat longer. Heat waves are also protected to cause two to three times more heat-related deaths by the mid-century (CNRA 2021). Socially vulnerable communities will experience the worst of these effects; these include impacts on aging populations, the elderly and children, people with chronic illness, and others that are sensitive to heat exposure. When combined with populations with inequities, such as poverty, housing, and language limitations, these populations are at a higher risk of heat-related illness and death.

Extent (Magnitude/Severity)
Freeze
Critical – In 2001, the NWS implemented an updated Wind Chill Temperature index. This index was developed to describe the relative discomfort/danger resulting from the combination of wind and temperature. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Overall, freeze impacts would likely be limited in the planning area, with the greatest impact being on the agricultural industry.
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Figure 4-18 National Weather Service Wind Chill Chart
Source: National Weather Service
Extreme Heat
Critical – Stanislaus County begins to experience hot weather in April or May of each year and the heat continues throughout the summer months. According to the Western Regional Climate Center (WRCC), the average high temperature for Stanislaus County based on the City of Modesto Cooperative Observer Program (COOP) in July is 94.3°F. Temperatures that are 10 degrees above normal are considered excessive. Figure 4-19 illustrates the relationship of temperature and humidity to heat disorders. The heat index describes how hot the heat‐humidity combination makes the air feel. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration. As the heat index rises, so do health risks. Specifically:
• When the heat index is 90°F, heat exhaustion is possible with prolonged exposure and/or physical activity.
• When it is 90° to 105°F, heat exhaustion is probable with the possibility of sunstroke or heat cramps with prolonged exposure and/or physical activity.
• When it is 105° to 129°F, sunstroke, heat cramps or heat exhaustion is likely, and heatstroke is possible with prolonged exposure and/or physical activity.
• When it is 130°F and higher, heatstroke and sunstroke are extremely likely with continued exposure.

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Figure 4-19 National Weather Service Heat Index Chart
Source: NWS
Note: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

The NWS has a system in place to initiate alert procedures (advisories, watches, and warnings) when high temperatures are expected to have a significant impact on public safety. The expected severity of the heat determines which type of alert is issued. The “California OES Contingency Plan for Excessive Heat Emergencies” (2014) indicates that through the use of historical weather and mortality data, the NWS and the CDPH have identified five major types of climate regions within California to account for climate differences among regions in order to recognize what constitutes an excessive heat event in each of the regions. When temperatures spike for two or more consecutive days without an adequate drop in nighttime temperature to cool the outdoor and indoor environments, there is a significant increase in the risk to socially vulnerable populations.

Overall, extreme heat impacts would be critical in the Planning Area, with the central portions of the County being most affected; greater impacts may also occur within the larger cities in Stanislaus County. Extreme heat will have an impact on vulnerable populations as well as impact the agricultural industry if the event occurs during certain times of the year. High heat waves are also projected to worsen with climate change.

Past Occurrences
There are seven weather stations or COOPs in Stanislaus County. The most central station in the City of Modesto (045738) is summarized below and in Figure 4-20 to illustrate the daily temperature averages in the County’s Planning Area.

Modesto City COOP Weather Station (045738), Period of Record 1906 to 2012 In Stanislaus County, monthly average maximum temperatures in the warmest months (May through October) range from the mid-60s to the upper 70s. Monthly average minimum temperatures from November through April range from the mid-40s to low-60s. The highest recorded daily extreme was 113°F on July 23, 2006. The lowest recorded daily extreme was 18°F on January 11, 1949. In a typical year, maximum temperatures do not exceed 84°F and minimum temperatures do not fall below 36°F. On average there is between 80 days per year above 90°F and about 20 days per year where the minimum temperatures is below freezing (32°F).
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Figure 4-20 Stanislaus County’s Daily Temperature Averages and Extremes Source: WRCC, www.wrcc.dri.edu/
A search of records from 1950 to 2021 in the National Centers for Environmental Information (NCEI) Storm Events Database showed that between 2000 and 2021 there were seven frost/freeze events and 40 excessive heat and heat events in Stanislaus County. No records for either frost/freeze or heat hazards were found between 1950 and 1999 in the NCEI database. Since 1953, there have been two federally declared disasters in the County for freeze events (refer to Table 4-3). In 2007, California's San Joaquin Valley farming communities were hit with freezing temperatures that severely affected the region's crops and resulted in Presidential disaster declarations (2007). The declarations made federal funds available to supplement unemployment compensation for farm laborers and other farm industry workers put out of work as a direct result of lost seasonal crops. Moreover, in 2012 and 2016, the USDA designated Stanislaus County as a disaster area due to freeze and extreme cold (refer to Table 4-4). On the other hand, there have not been any federally declared disasters in the County for extreme heat (refer to Table 4-3), but the USDA has declared crop losses due to drought conditions often associated with consecutive extreme heat days or prolonged heat waves (refer to Table 4-4). During these events, California's San Joaquin Valley farming communities were severely affected, and the region’s agricultural industry and the economy was impacted.

Probability of Future Occurrences
Highly Likely – Temperatures at or above 95°F are common most summer days throughout Stanislaus County, and it is highly likely that extreme heat will continue to occur on an annual basis in the future. In the past, extreme heat events have occurred every few years with four of the major excessive heat events occurring in 2021 over Memorial Day weekend with additional events in June and July. During the four-day excessive heat event in June, Modesto recorded a record daily high temperature of 107 degrees and over 22 cooling centers were available in Sacramento, Butte, Calaveras, Placer, San Joaquin, Tuolumne, Yolo, and Solano counties. Based on the NCEI data, 40 excessive heat and heat events incidents over a 22-year period equates to a major event every 1.8 years and a 55 percent chance (probability) of a major excessive heat event in any given year.

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Climate Change Considerations
Heat waves will likely become more frequent, which will have a direct impact on human health in terms of heat-related illness. With the general trend of increased warming of average temperatures, extreme high temperatures will also increase. Cascading impacts include increased stress on water quantity and quality, degraded air quality, and increased potential for more severe or catastrophic natural events such as heavy rain, droughts, and wildfire. Another cascading impact includes increased duration and intensity of wildfires with warmer temperatures. According to the 2013 document, “Preparing California for the Extreme Heat”, Cal-Adapt projects that throughout California urban and rural population centers will experience an average of 40 to 53 extreme heat days by 2050 and an average of 40 days by 2099; compared to a historical average of 4 per year (Cal-Adapt 2013). Cal-Adapt also projects that overall temperatures are expected to rise substantially throughout this century. Similarly, in the Draft Extreme Heat Action Plan, the daily maximum average temperature is expected to rise 4.4°F – 5.8°F by 2050 and 5.6°F – 8.8°F by 2100 (CNRA 2021).

Future temperature estimates from Cal-Adapt for the County under high and low emission scenarios are shown in Figure 4-21. The top graph shows the number of days per year when daily maximum temperature is above the extreme heat threshold of 101.2°F under the RCP 8.5 scenario (business as usual). The bottom graph shows the number of days per year when daily maximum temperature is above the extreme heat threshold of 101.2°F under the RCP 4.5 scenario.

Figure 4-21 Stanislaus County: Future Extreme Heat Days in High and Low Emission Scenarios Source: Cal-Adapt 2021
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A recent study on extreme heat released by the Union of Concern Scientists in July 2019 analyzed three global climate scenarios associated with different levels of heat-trapping emissions and future warming.

The results of the analysis showed that with no actions taken to reduce heat-trapping emissions by midcentury (2036-2065) the average number of days per year in the United States with a heat index above 100°F will double, while the number of days per year above 105°F will quadruple.

Alternately, regarding extreme cold temperatures, a new study funded by NOAA Climate Program Office’s Modeling, Analysis, Predictions and Projections (MAPP) program, used machine learning techniques and linked extreme cold weather in the United States to Arctic warming. Accelerated Arctic warming, known as Arctic amplification, has been evident since the 1990’s as one of the more robust signs of global warming.

MAPP program’s researchers concluded that Arctic warming and climate change are likely contributing to the increasing frequency of Arctic polar vortex stretching events, which deliver extreme cold from the north pole to the United States and Canada, including one event that occurred before the winter 2021 in Texas when a cold wave caused the collapse of the state’s infrastructure and resulted in approximately $80-130 billion in direct and indirect economic losses (Cohen et al 2021).) Vulnerability Assessment
General Property
All property is vulnerable during severe weather events, but property and buildings are less likely to be vulnerable to extreme temperature events the same way as other severe weather events, like wind and hail can damage property. However, recent research indicates that the impact of extreme temperatures has been historically under-represented. The risks of extreme temperatures are often profiled as part of larger hazards, such as severe winter storms or drought. However, as temperature variances occur separate from larger hazards or outside of the expected seasons, it is important to examine them as stand-alone hazards.

Extreme heat may overload demands for electricity due to the need to run air conditioners in homes and businesses during prolonged periods of exposure. Extreme heat may also be a secondary effect of droughts or may cause temporary drought-like conditions. For example, several weeks of extreme heat increases evapotranspiration and reduces moisture content in vegetation, leading to higher wildland fire vulnerability for that time period even if the rest of the season is relatively moist.

Extreme cold temperatures impact structures when pipes or water mains freeze and burst, causing damage.

Cold temperatures can also, in the most extreme of circumstances, make materials more fragile and breakable. Extreme cold temperatures may also lead to higher electricity and natural gas demands to maintain appropriate indoor heating levels combined with damages caused to the delivery infrastructure such as frozen lines and pipes. Cold temperatures may also impact transportation. Exposed populations may be at risk while waiting for public transportation, particularly when combined with wind chill, and some vehicles may not start which impacts the commute of the workforce and, in worst-case scenarios, the movement of emergency services personnel.

People
Recent research indicates that the impact of extreme temperatures, particularly on vulnerable populations has been historically under-represented. The risks of extreme temperatures are often profiled as part of larger hazards, such as drought, severe weather, or wildfire. Extreme temperatures may present health concerns to individuals that work outside in extreme temperatures. Extreme temperatures can also cause serious injury or death. During periods of extreme temperatures, inadequate protection from and exposure to harsh elements is especially dangerous. Moreover, elevated temperatures have the potential to increase the rate of ground-level ozone formation. Ground-level ozone can lead to urban smog which has adverse health effects including difficulty breathing, shortness of breath, coughing and sore or scratchy throat, aggravation of lung diseases such as asthma, emphysema, and chronic bronchitis, and increased susceptibility to vector-borne diseases
Social Vulnerability
Traditionally, the very young and very old are considered at higher risk to the effects of extreme temperatures, as are people in poor physical health; but any populations outdoors in the weather are exposed, including otherwise young and healthy adults and persons experiencing homelessness. Arguably, the young-and-otherwise-healthy demographic may be more exposed and experience a higher vulnerability because of the increased likelihood that they will be out in the extreme temperature, whether due to 934
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commuting for work or school, working outdoors such as construction, utilities, snow removal, or for recreational reasons. While everyone is vulnerable to extreme temperature incidents, some populations are more vulnerable than others. For example, extreme heat poses the greatest danger for Stanislaus County’s outdoor laborers, who support the County’s agriculture economy and are exposed to extreme temperatures and are at higher risk of heat-related illnesses than other populations of the County. In short, climate-vulnerable communities will experience the worst of these effects. Additionally, according to the Draft Extreme Heat Action Plan prepared by the State, heat risk is associated and correlated with physical, social, political, and economic factors (CNRA 2021). When combined with existing health inequities and poverty, linguistic isolation, and housing insecurities, this hazard puts individuals at a disproportionately high risk of heat-related illness.

Government Services
Extended power outages resulting from extreme temperature events affect the delivery of government services in the absence of backup power sources. Responders are as vulnerable to the effects of extreme temperature events as the general population and may receive increased calls during extended periods of such events. During an extended extreme temperature event, the public would expect alerts and warnings.

For extreme heat events, the public would also expect the opening of cooling shelters by the government Similarly, the public should expect the opening of warming shelters by the government Critical Facilities and Infrastructure
Extreme heat can affect road infrastructure, damaging and buckling road surfaces. Other direct impacts on critical infrastructure include power line sagging and power surges. Critical infrastructure such as waterpumping stations that rely on public utility systems that could be overloaded may result in impacts during extreme heat events. Extreme heat has also been shown to accelerate wear and tear on the natural gas system and electrical infrastructure (CNRA 2018a). Projected increases in summer demand associated with rising temperatures may increase risks to energy infrastructure and may exceed the capacity of existing substations and distribution line infrastructure and systems. Peak demand exceeding the local utility’s capacity for supply can also lead to blackout or brownout conditions, or Public Safety Power Shutoffs (PSPS).

Similar to extreme heat events, the secondary impacts of extreme cold can also affect the supporting mechanisms or systems of a community’s infrastructure. For example, when extreme cold is coupled with high winds or ice storms, power lines may be downed, resulting in an interruption in the transmission of that power and shutting down electric furnaces, which may lead to frozen pipes in homes and businesses.

Furthermore, the loss of utilities or power outages during extreme temperature events could result in adverse secondary impacts on sensitive populations. Electrical power outages may impact response capabilities or care capabilities for hospitals and clinics.

Economy
Extreme heat impacts on the economy may be more indirect compared to other hazards. Stanislaus County has a large agricultural economy. As noted previously outdoor laborers who are exposed to extreme heat and at a high risk of heat-related illnesses, and a long-term heat event could cause work interruptions.

Crops are also impacted by heat events and could have an impact on the overall economy in the County.

According to the USDA RMA Indemnity Report, since 2007 there have been 12,316 acres lost to heat resulting in $11,737,982 indemnity payment due to insured crop loss. There is an estimated $782,532 of annualized crop loss due to heat.

Prolonged freezing temperatures can also damage or destroy crops, affecting the economy and agricultural jobs in the County. According to the USDA RMA Indemnity Report, since 2007 there have been 28,830 acres lost to freeze/frost resulting in $22,429,754 indemnity payments due to insured crop loss. Annualized crop loss is estimated to be $1,602,125 due to freeze events.

Historic, Cultural and Natural Resources
Extreme heat may cause temporary drought-like conditions. For example, several weeks of extreme heat increases evapotranspiration and reduces moisture content in vegetation, leading to higher wildfire vulnerability for that time period even if the rest of the season is relatively moist. Extreme cold can cause 935
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vegetation to freeze and cause high stress, leading to the decline and even disappearance of vegetation on or within landscapes.

Future Development
Since structures are not usually directly impacted by extreme temperature fluctuations, continued development is less impacted by this hazard than others in the plan. However, pre-emptive measures such as construction of green buildings that require less energy to heat and cool, use of good insulation on pipes and electric wirings, and smart construction of walkways, parking structures, and pedestrian zones that minimize exposure to severe temperatures may help increase the overall durability of the buildings and the community to temperature variations. Continued development also implies continued population growth, which raises the number of individuals potentially exposed to variations in temperature. Public education efforts should continue to help the population understand the risks and vulnerabilities of outdoor activities, property maintenance, and regular exposures during periods of extreme temperature events.

Risk Summary
• The average annual maximum temperature is 94.3°F and on average there are between 80 days per year above 90°F.
• The highest recorded temperature for the central portion of the County in Modesto is 113°F on July 23, 2006, while the lowest recorded temperature was 18°F on December 13, 1932. • Extreme temperatures can have considerable impacts on human health, the natural environment, and the economy.
• 40 excessive heat and heat events incidents over a 23-year period equate to a major event every 1.8 years and a 55 percent chance of a major excessive heat event in any given year. • Seven frost and freeze events incidents over a 22-year period equate to a major event every 3.14 years and a 32 percent chance of a major frost/freeze event in any given year. • California’s urban and rural population centers will experience an average of 40 to 53 extreme heat days by 2050 and an average of 40 days by 2099; compared to a historical average of 4 per year.

Overall temperatures are also expected to rise substantially throughout this century. The daily maximum average temperature is expected to rise 4.4°F – 5.8°F by 2050 and 5.6°F – 8.8°F by 2100. • Extreme temperatures can have considerable impacts on human health, the natural environment, and the economy.
• The County’s agriculture economy is at risk of extreme temperatures from outdoor laborers being vulnerable to heat illnesses as well as crop losses due to heat and freeze and frost. • Since 2007 there have been 41,146 acres of crop lost to extreme temperatures and a combined $34,167,736 indemnity payments made for insured crop loss to due freeze/frost and heat events. • The very young, the very old, people with poor physical health and those experiencing homelessness are more susceptible to the impacts of extreme temperatures. • Climate change is expected to result in higher average temperatures and more extreme heat events in the Central Valley and have a “high” influence on the number of extreme heat days; climate change is also expected to result in more extreme cold events in the US. • The significance of extreme temperatures in the County is Medium. • Related hazards – Agricultural Pest and Disease, Drought, Wildfire Table 4-53 Hazard Risk Summary – Extreme Temperatures: Freeze and Extreme Heat Jurisdiction Geographic Area Probability of
Future Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Extensive Highly Likely Critical Medium Yes City of Ceres Extensive Highly Likely Critical Medium No City of Hughson Extensive Highly Likely Limited Medium Yes City of Modesto Significant Highly Likely Critical High No City of Newman Extensive Highly Likely Critical Medium Yes City of Oakdale Extensive Highly Likely Critical Medium No City of Patterson Extensive Highly Likely Critical Medium Yes City of Riverbank Extensive Highly Likely Critical Medium No City of Turlock Significant Highly Likely Critical High Yes 936
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Jurisdiction Geographic Area Probability of
Future Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
City of Waterford Extensive Highly Likely Critical Medium No County Office of
Education Extensive Highly Likely Critical Medium No

4.3.8 Flood
Hazard Description
A flood is the temporary inundation of water or mud on normally dry land. Heavy or prolonged rain or dam collapse can cause inundation, as can flash floods. Urban flooding occurs in developed areas where the amount of water generated from rainfall and runoff exceeds the storm water systems’ capacity. As land is converted from agricultural to urban uses, it often loses its ability to absorb rainfall. Rain flows over impervious surfaces such as concrete and asphalt and into nearby storm sewers and streams. This runoff can result in the rapid rise of floodwaters. During urban floods, streets can become inundated, and storm drains often back up because of the volume of water and become blocked by vegetative debris like yard waste, which can cause additional flooding. Development in or near the floodplain puts lives and property at risk. Flood damage can include structure inundation, erosion of stream banks, road embankments, foundations footings for bridges, impact damage from debris, blockage of infrastructure, cropland destruction, sewage releases from damaged tanks, and economic loss to agriculture.

Floods are among the most frequent and costly natural disasters in terms of human hardship and economic loss. Certain health hazards are common to flood events. Standing water and wet materials in structures can become breeding grounds for microorganisms such as bacteria, mold, and viruses. This can cause disease, trigger allergic reactions, and damage materials long after the flood. When floodwaters contain sewage or decaying animal carcasses, infectious disease becomes a concern. Direct impacts, such as drowning, can be limited with adequate warning and public education about what to do during floods. Where flooding occurs in populated areas, warning and evacuation will be of critical importance to reduce life and safety impacts.

Floodplains are defined as the areas immediately adjacent to a channel from a river, stream, or other waterway. Floodplains are illustrated on inundation maps, which show areas of potential flooding and water depths. In its common usage and based on FEMA guidelines, the floodplain most often refers to the area that is inundated by the 100-year flood, or the flood that has a one percent chance occurrence in any given year of being equaled or exceeded. The 1%-annual-chance flood is the national minimum standard to which communities regulate their floodplains through the FEMA National Flood Insurance Program (NFIP). The 500-year flood is the flood that has a 0.2 percent chance of being equaled or exceeded in any given year.

A 0.2%-annual-chance flood event would be slightly deeper and cover a greater area than a 1%-annualchance flood event. The potential for flooding can change and increase through various land use changes and changes to land surface, which may result in a change to the floodplain. A change in environment can create localized flooding problems inside and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity.

A levee is a raised area that runs along the banks of a river or canal. Levees reinforce the banks and help prevent flooding. By confining the flow, levees can also increase the speed of the water. Levees can be natural or manmade. A natural levee is formed when sediment settles on the riverbank, raising the level of the land around the river. To construct a manmade levee, workers pile dirt or concrete along the riverbanks, creating an embankment. This embankment is flat at the top, and slopes at an angle down to the water.

For added strength, sandbags are sometimes placed over dirt embankments.

Levees provide strong flood protection, but they are not failsafe. Levees are designed to protect against a specific flood level and could be overtopped during severe flood events. Levees reduce, not eliminate, the risk to individuals and structure behind them. A levee system failure or overtopping can create severe flooding and high-water velocities. It is important to remember that no levee provides protection from events for which it was not designed, and proper operation and maintenance are necessary to reduce the probability of failure.

Riverine flooding – Riverine flooding, defined as the condition when a watercourse (e.g. river or channel) exceeds its “bank-full” capacity, generally occurs as a result of prolonged rainfall, or rainfall that is combined 937
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with already saturated soils from previous rain events. This type of flood occurs in river systems whose tributaries may drain large geographic areas and include one or more independent river basins. The onset and duration of riverine floods may vary from a few hours to many days. Factors that directly affect the amount of flood runoff include precipitation amount, intensity and distribution, the amount of soil moisture, seasonal variation in vegetation, snow depth, and water-resistance of the surface due to urbanization.

Intense storms can overwhelm the local waterways as well as the integrity of any flood control structures.

The warning time associated with slow rise floods assists in life and property protection.

Localized flooding – Localized flooding problems are often caused by flash flooding, severe weather, or an unusual amount of rainfall. Flooding from these intense weather events usually occurs in areas experiencing an increase in runoff from impervious surfaces associated with development and urbanization as well as inadequate storm drainage systems.

Levee Failure – Flooding from the failure of levees throughout the County or upstream is also of concern, as there are levees along various waterways in Stanislaus, specifically along the San Joaquin River Flood Control System. A catastrophic flood control structural failure could easily overwhelm local response capabilities to save lives and require mass evacuations. Impacts to life safety will depend on the warning time and the resources available to notify and evacuate the public. Loss of life could result, and there could be associated health concerns as well as negative effects to local buildings and infrastructure.

The potential for flooding can change and increase through various land use changes and changes to land surface, which result in changes to the floodplain. Environmental changes can create localized flooding problems in and outside of natural floodplains by altering or confining natural drainage channels. These changes are most often created by human activity.

Encroachment into areas subject to inundation by floodwaters having rapid flows aggravates the risk of flood damage and heightens potential flood hazards by further increasing velocities. To reduce the risk of property damage in areas where the stream flows are high, the community may wish to restrict development in areas outside the floodway. FEMA defines a regulatory floodway as the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water-surface elevation more than a designated height. The floodway is illustrated in Figure 4-22 below. The area between the floodway and 100-year floodplain boundaries is termed the floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water-surface elevation of the base flood more than 1 foot at any point. Typical relationships between the floodway and the floodway fringe and their significance to floodplain development are shown in the following schematic. 938
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Figure 4-22 Floodway Schematic
Source: Guidance for Flood Risk Analysis and Mapping – FEMA, 2019 Geographic Area
Significant – Stanislaus County is located within the San Joaquin River watershed. The San Joaquin River is one of the longest rivers in Central California after the Sacramento River. The 366-mile long river starts in the Sierra Nevada and flows through the agricultural region of the Northern San Joaquin Valley, where it meets up with the Sacramento River at the Sacramento-San Joaquin Delta, a 1,000-sqaure mile system of channels and islands that drains more than 40 percent of the State’s lands. It eventually flows through to Suisun Bay, San Francisco Bay, and the Pacific Ocean.

An important source of irrigation water as well as a wildlife corridor, the San Joaquin is among the most heavily dammed and diverted of California's rivers. Over the length of the San Joaquin River is fed by many other rivers and streams, and most notably the Stanislaus and Tuolumne rivers in Stanislaus County.

Surface water from the San Joaquin River is also stored and diverted within the watershed. Most of the surface water in the upper San Joaquin River is stored and diverted at Millerton Lakes Friant Dam near Fresno In the central portion of the watershed, many agricultural and municipal users received water from irrigation districts, such as the Modesto, Merced, Oakdale, South San Joaquin, and Turlock Irrigation Districts. These river system tributaries and surface water diversions are further described below.

Tuolumne River
The Tuolumne River flows for 149 miles through Central California, from the high Sierra Nevada and joins the San Joaquin River in the Central Valley. Originating at over 8,000 feet above sea level in Yosemite National Park, the Tuolumne drains a rugged watershed of 1,958 square miles, carving a series of canyons through the western slope of the Sierra.

There are various flood controls along the Tuolumne River, but flooding has happened in the past and is a risk for urban development in Stanislaus County. Due in large part to Don Pedro Dam, authorities have flood controls in place on the Tuolumne River. For example, TID can regulate the number of flows going through the river to mitigate possible floods, however additional flood storage space is needed. Along the Tuolumne River, it takes a lot of rain and snowmelt to impact the storage capacity of Don Pedro Reservoir to the point where it starts impacting downstream residents and property, however 100-year flood events and variability in snowpack and precipitation due to climate change can potentially impact these flood controls thereby limiting the protection of downstream communities. When flood events do occur, most of the impacts occur in the downtown Modesto area where there are some low-lying trailer parks along the 939
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Tuolumne River, near 9th Street and according to the HMPC at the Sutter Wastewater Treatment Plant (WWTP) located downstream of Highway 99. (abc10 2019)
New Don Pedro Dam
New Don Pedro Dam is an earthen embankment dam across the Tuolumne River, about two miles northeast of La Grange, in Tuolumne County. The dam provides irrigation water storage, flood control and hydroelectricity production, and impounds Don Pedro Reservoir in the foothills of the Sierra Nevada. New Don Pedro Dam is owned and operated by the MID and TID.

The Don Pedro Reservoir has a capacity of 2,030,000 acre-feet, of which 340,000 acre-feet is reserved for flood control and 1,381,000 acre-feet is available for irrigation, municipal water supply, and hydroelectric generation. The flood control reservation is one of the smallest among major California reservoirs because it allows for more water to be stored for power generation, but this has often resulted in inadequate flood protection such as in 1997 when the dam released more than 50,000 cubic feet per second (cfs) – almost six times the capacity of downstream levees.

In 2017, the Don Pedro spillway was opened for the first time in nearly 20 years. When the spillway opened, authorities were expecting flows between 18,000 and 30,000 cfs, but actual flow releases did not near 30,000 cfs and instead topped at a little above 19,000 cfs, but generally stayed at 15,000 cfs (TID 2017).

Flooding did not pose much of an impact to some residential areas; however, several mobile home communities in the County were impacted. Before the spillway opened, TID, the area's provider for water and power, cut the power to some in the area homes because of the increasing water levels.

The 1997 January storms resulted in a 100-year flood. It set a record height for Tuolumne River at 71 feet above mean sea level (msl) and had flows around 60,000 cfs. Don Pedro Dam had filled up and began uncontrolled releases. The uncontrolled releases and the uncontrolled flows from Dry Creek stream overwhelmed levees and induced massive flooding directly into the Tuolumne and San Joaquin Rivers.

Extensive flooding eventually impacted the City of Modesto (Stanislaus County 2019). As noted in the 2017 LHMP, regulation of the flows from Don Pedro limits flooding along the Tuolumne River but does not completely eliminate it (Stanislaus County 2017).

Figure 4-23 below shows Tuolumne River with relation to the Cities of Modesto, Turlock, and Waterford, as well as the Lake Don Pedro, also referred to as Don Pedro Reservoir. 940
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Figure 4-23 Tuolumne River
Source: USGS
Stanislaus River
The Stanislaus River is a tributary of the San Joaquin River. The main stem of the river is 96 miles long and measured to its furthest headwaters it is about 150 miles long. Stanislaus River drains parts of five counties.

The Stanislaus River is known for its swift rapids and scenic canyons in the upper reaches, and is heavily used for irrigation, hydroelectricity, and domestic water supply.

New Melones Dam
New Melones Dam is an earth and rock filled embankment dam on the Stanislaus River, about 5 miles west of Jamestown, on the border of Calaveras County and Tuolumne County. The water impounded by the 625-feet tall dam forms New Melones Lake, California's fourth largest reservoir in the foothills of the Sierra Nevada east of the San Joaquin Valley. The dam serves mainly for irrigation water supply, and also provides hydropower generation, flood control, and recreation benefits.

New Melones Lake, when at full pool of 1,088 ft above msl, encompasses 12,500 acres of surface water and a volume of 2,400,000 acre-feet. About 450,000 acre-feet, 19 percent of the reservoir's capacity, is reserved for flood control. During flooding events, the dam is operated to keep flows on the Stanislaus River below 8,000 cu ft/s, although this flow estimate may be lowered depending on flow conditions in the San Joaquin River. Between 1978 and 2010 the dam prevented a total of $505 million in flooding damages (adjusted for inflation), including $231 million during the New Year's flood of 1997 (US Bureau of Reclamation 2010). As a primary flood control structure, it would protect 35,000 acres (14,000 ha) of farmland as well as the towns of Oakdale, Riverbank and Ripon from flooding. Figure 4-24 below shows Stanislaus River with relation to Modesto and Oakdale, as well as the New Melones Lake. 941
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Figure 4-24 Stanislaus River
Source: USGS
Mid San Joaquin River
The Mid San Joaquin River region extends from the Merced-San Joaquin River confluence to the Stanislaus -San Joaquin River confluence. Any areas protected by the State Plan of flood control facilities, and other areas that experience flooding are connected to the State flood control facilities are included in the Mid San Joaquin River Regional Flood Management Plan (MSJR RFMP). The MSJR RFMP was first developed in 2013-2014, updated in 2017, and is currently being updated in 2022 through the participation of a range of stakeholders primarily from Stanislaus County. This regional planning effort was created to give stakeholders the opportunity to develop a plan to reduce flood risks in the area from the confluence of the Merced and the San Joaquin Rivers to the confluence of the Stanislaus and the San Joaquin Rivers. The result of these efforts is a vision for a safer and more flood-resilient region that identifies challenges and opportunities for flood management and a prioritized list of actions for DWR to consider in their Central Valley Flood Protection Plan (CVFPP). The MSJR RFMP also identifies priority flood protection projects to be carried out by local sponsors. The HMPC consisted of a stakeholder from the MSJR team, which consists of representation from the DWR, Reclamation District 2092, Stanislaus County, and consultant staff.

Millions of dollars have been raised by local sponsors from a variety of state, federal and other sources to implement the flood control projects. The major focuses of MSJR RFMP include identifying new projects consistent with regional flood management goals and state polices, ways to improve regional coordination of flood management and ways to improve regional resilience to evolving flood hazards. Figure 4-25 below shows the flood control area of MSJR RFMP.
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Figure 4-25 Mid San Joaquin River Regional Flood Management Plan - Flood Control Area Data source: MSJR RFMP
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Dry Creek
Dry Creek is a stream in Stanislaus County and is a tributary to the Tuolumne River. Dry Creek originates just north of the Modesto Reservoir. It then flows north of the City of Waterford. Continuing west, it flows through Modesto. Dry Creek has been historically subject to flooding the San Joaquin Valley in the vicinity of present-day Modesto. Dry Creek traverses the City of Modesto. Because there are no flood control structures along Dry Creek, such as a dam, this waterway has a higher probability of flooding than the other major rivers in the region (Modesto Bee 2021). The Stanislaus County 2017 LHMP also mentioned that Dry Creek exhibits seasonal flooding threat.

Central Valley Flood Protection Plan (CVFPP)
The physical risks associated with potential flooding and the regulatory requirements for floodplain management are important considerations when decisions are being made regarding future land use throughout the County. Those same risks guide the local and community-level emergency response needs.

Economic growth and prosperity in Stanislaus County are dependent upon federal, state, and local agency involvement on regional and local flood management systems. Flood protection regulations within California have been increased over the past few years through legislation. This legislation included the requirement for the California DWR and Central Valley Flood Protection Board (CVFPB) to prepare and adopt the CVFPP by 2012 and update every 5 years. The legislation also established certain flood protection requirements for local land use decision-making based on the CVFPP. The law sets a higher standard for flood protection for the entire San Joaquin Valley. The standard was set for an urban level flood protection necessary to withstand a 1 in 200 chance of a flood event occurring in any given year (200-year flood) for areas developed or planned to have a population of at least 10,000. It also requires impacted counties to collaborate with cities to develop flood emergency response plans.

Figure 4-26 shows the extent of a 200-year flood event based on the Comprehensive Study compiled by USACE. This map includes a 100-year flood event layer compiled by DWR’s Awareness Floodplain Mapping project. Both data layers come from the Best Available Maps (BAM) developed and compiled by DWR.
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Figure 4-26 Stanislaus County DWR & Comprehensive Flood Hazards In 2009, FEMA completed their Digital Flood Insurance Rate Map (DFIRM) conversion and updated a number of flood zone areas using 2005 levee certification criteria. On July 27, 2020, FEMA released the updated FIRMs for Stanislaus County. In 2007, the California DWR completed their Awareness Floodplain Mapping of Stanislaus County to identify all pertinent flood hazard areas that are not mapped under FEMA’s program, which provides an additional resource for identifying special flood hazard areas within the County.

Extent (Magnitude/Severity)
Critical – Flooding has been a major problem throughout the history of Stanislaus County, particularly with the encroachment of urban growth into flood plains. Major floods have occurred in 1861, 1938, 1950, 1955, 1969, 1983, 1995, 1997, and 1998. Minor flooding occurred in 2006 with limited impacts to County property.

The Central Valley Flood Protection Board (known as the Reclamation Board prior to 2007) has identified and adopted designated floodways, defined in feet per second of flow, along the San Joaquin River, 945
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Stanislaus River, Tuolumne River, and portions of Dry Creek. Seasonal flooding along Dry Creek, San Joaquin River and Tuolumne River is common during very wet years or periods.

The FEMA Flood Insurance Rate Map (FIRM) provides information on flood risk in Stanislaus County using 100 and 500-year floodplain GIS mapping layers. Areas within the 100-year floodplain zone have a 1% annual exceedance probability of flood, meaning a flood has a 1% chance of being equaled or exceeded in any single year in those areas. Areas between the limits of the 100-year and 500-year floodplain zone have a 0.2% annual chance of flooding. A portion of Stanislaus County continues to be subject to inundation during flood events, as approximately 100,447 acres have been determined to be in the FEMA floodplain.

The extent of the floodplain is shown in Figure 4-27. The 100-year and 500-year floodplains combined cover 10.3% of the County. Therefore, a potential flood hazard would threaten a significant geographic area (10% – 50%) of the County, and if a flood event would occur the damage associated with flooding could impact between 20% to 50% of the property.

Figure 4-27 Stanislaus County 100-year and 500-year Floodplain 946
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The Department of Housing and Urban Development (HUD) has also developed flood hazard zones, which are referenced in the County's Flood Control Ordinance and used for insurance purposes. Any nonagricultural encroachment into these areas requires special permits that are difficult to obtain and often costly to implement. Permits for encroachment into the designated floodways must be obtained from the Central Valley Flood Protection Board. The County administers other permits. These measures still do not control flood hazards for existing development. Information regarding flood-prone areas as shown on the HUD maps is available in the Department of Public Works.

Life and property loss could occur as well as damage to agricultural land. Road and bridge closures, and communication systems may cause disruption to normal process. Population most vulnerable are those residents living in low-lying trailer parks along the rivers and those experiencing homelessness. There is usually sufficient time to alert and warn those that may be affected. There are no County buildings or historical buildings located in these areas. The Sutter WWTP in the City of Modesto could also experience problems should flood waters rise given its proximity to the floodplain.

As mentioned previously, the 1997 flood was one of the worst flood events that occurred in Stanislaus County and the Northern San Joaquin Valley. Precipitation in the Sierra Nevada Mountain range produced an above-normal snowpack and saturated soils during November and December 1996. A series of storms from December 29, 1996, through January 4, 1997, brought heavy and relatively warm precipitation across much of California. Precipitation totals of up to 24 inches were recorded for the week. Virtually all of this precipitation was rain because temperatures were above freezing at elevations as high as about 9,000 feet.

Rainfall on snow and saturated soils caused rapid runoff and widespread flooding in the major drainage basins. Most flooding occurred near the tributaries and main channels of the Sacramento and San Joaquin Rivers. Localized flooding from intense rainfall was widespread throughout Northern California. Total flood damages in 1997, including damage to flood control structures, were estimated at nearly $2 billion dollars.

This was the highest amount of flood damage in the State's history at the time. Disaster areas were declared in 48 of California's 58 counties (USGS 1999).

Previous Occurrences
Between 1992 and 2002, every county in California was declared a federal disaster area at least once for a flooding event. California has a repetitive and destructive flood history. Of the 336 federally declared disasters in California between 1950 and 2021, 37 were flood related. This makes flooding second only to fire in the number of federal disaster declarations in the State. Historically, floods have been the second most frequent cause of disaster in Stanislaus County.

According to the 2017 Stanislaus County LHMP, there have been clusters of flooding incidents within the County approximately every 14 years. Stanislaus County has had three flood events that were federally declared disasters, once in 1964, once in 1969 and again in 2017. FEMA’s Flood Insurance Study also listed flooding events in 1938, 1950, 1955, 1958, 1969, 1973, and 1997. Additionally, NOAA’s NCEI database lists 12 flood or flash flood events which have occurred in the County between 1950 and 2021.

Table 4-54 below highlights several notable flood events in the County that resulted in significant damages or involved federal disaster declarations.

Table 4-54 Major Floods in Stanislaus County
Date of Event Incident Description
December 1964 –
January 1965
The Christmas flood of 1964 was a major flood in the United States' Pacific Northwest and some of Northern California between December 18, 1964, and January 7, 1965, spanning the Christmas holiday. Considered a 100-year flood, it was the worst flood in recorded history on nearly every major stream and river in Northern California. California Governor Pat Brown was quoted as saying that a flood of similar proportions could "happen only once in 1,000 years," and it was often referred to later as the Thousand Year Flood.

Governor Brown declared 34 counties in the region disaster areas while Stanislaus County was one of them.

January and
February 1969
The flood of 1969 was actually two distinct events – one the result of more than a week of rain in January 1969 and a subsequent flood from a second wave of rain the following month. The damage from these storms was a statewide event, with 35 of 58 California Counties being declared federal disaster areas. (The Press-Enterprise 2016) 947
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Date of Event Incident Description
December 22 – 23,
1996
Heavy rain, snow melt, and large reservoir releases in anticipation of more rain caused the Tuolumne River to rise about one foot above flood stage. According to NCEI, this event also resulted in $10,000 in property damage.

January 23 – 24,
2000
Persistent and heavy rain produced runoff which exceeded the capacity of a Salida neighborhood storm drain pond. The result flooded Doreen Court and a number of residences on the street. Four houses sustained interior flooding while an additional four homeowners sustained garage flooding. According to NCEI, this event also resulted in $20,000 in property damage.

January 1997 Several periods of rain (with snow to unusually low elevations in the mountains) beginning December 20, 1996, set up saturated conditions that finally gave way at the beginning of the month as subtropical air moved in and melted snow up to the 8000-foot level. The moist airmass also left huge amounts of additional rain in the valley, foothills, and mountains with its nearly ideal orographic enhancement conditions.

A dry spell from the 3rd to the 11th allowed the flooding to subside in the Shasta-Cascades and the Sierra Nevada mountains, but flooding worsened in the valley below. As the runoff moved downstream and flood control dams operated at near maximum releases, stress on the Sacramento River and San Joaquin River levees resulted in numerous levee breaks, especially from the 4th to the 10th. The result was considerable inundation of the areas near the break. Heavy rains returned at the end of the month, beginning on the 22nd and lasting through the 27th. These storms were colder in nature, with flooding problems mainly in the foothills and valley floor. Levees continued to break in the Sacramento-San Joaquin River delta as the floodwaters headed out to San Francisco Bay.

The variety and magnitude of the damage were huge. Besides five deaths in interior Northern California, at least 120,000 total people were evacuated. The flooding damaged or destroyed 20,000 homes and 1500 businesses, at a minimum, in the estimated 250 square miles that were inundated. Early estimates put the total bill for the State at $1.6 billion, much of it in interior Northern California. Infrastructure took the hardest hit, conservatively estimated at $400 million for roads and $300 million for flood control facilities. Agricultural damage is estimated at $250 million or more. Hardest hit included the artichoke and winter wheat crops, and the dairy industry, losing thousands of livestock drowned. The American Red Cross labeled the flooding a level 5 disaster--their highest rating.

January 1 – 3,
2006
A series of warm winter storms brought heavy rain, mudslides, flooding, and high winds to Northern California, resulting in levee overtopping and breaching as well as transportation being difficult throughout the area. A Stanislaus County woman died while crossing a flooding stream on foot. According to NCEI, this event also resulted in $100,000 in property damage.

April 14 – 15, 2006 Heavy rain from afternoon thunderstorms caused flooding in the Riverbend area of Modesto. Nearby areas had been flooded earlier in the week due to high river levels.

Several houses and some local roads were flooded. According to NCEI, this event also resulted in $250,000 in property damage.

January and
February 2017
During January and February 2017, three atmospheric river storm events swept across California, bringing high winds, substantial precipitation, and flooding, which has severely impacted counties throughout the State. On January 23, 2017, the Governor of the State of California proclaimed a state of emergency due to flood conditions in the State, specifically listing Stanislaus County one of the affected counties. At that time, rivers and creeks in Stanislaus County were at or near flood stage, and two residential communities adjacent to the San Joaquin River have been flooded and displaced numerous families. Numerous roads in Stanislaus County were flooded and were closed to traffic due to dangerous conditions. Stanislaus County also proclaimed local emergency.

Source: NCEI Storm Events Database, FEMA
Figure 4-28 shows past flooding in Stanislaus County from the 2017 floods. 948
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Figure 4-28 Image of Past Flooding in Stanislaus County Source: The Modesto Bee, Images of February 2017 flooding Probability of Future Occurrences
Likely – Due to the history of past flooding events and the natural drainage pattern of the Planning Area, flooding in Stanislaus County is likely to continue to occur. The potential for failure of one of the many levees throughout the County could create more risk for flooding. The 100-year flood is the flood that has a one percent chance in any given year of being equaled or exceeded. Based on past events, flooding events less severe than a 100-year flood and those outside of the 100-year floodplain occur frequently during periods of heavy rains. According to the NCEI Storm Events Database, there have been 12 flood events recorded for Stanislaus County between 1950 and 2021. This means there is a 17% chance of a flood event occurring in a given year. Significant flooding occurs in Stanislaus County approximately every six years.

According to the 2017 Stanislaus County LHMP, flooding risks are present among several creeks and rivers, including Del Puerto Canyon, Dry Creek, Orestimba Creek, Salado Creek, San Joaquin River, Stanislaus River, and the Tuolumne River. The Dry Creek watershed is a major factor in flooding in eastern Stanislaus County and the east side of Modesto. The watershed was traditionally un-monitored and uncontrolled. To improve monitoring capabilities, in 2011 Stanislaus County purchased a Remote Automated Weather System (RAWS) to help monitor rainfall on the watershed near Crabtree Road. TID is now planning to install another weather station on the upper Dry Creek watershed to give further capabilities for managing this flood hazard. The MSJR planning group is also focused on increasing transitory storage on the San Joaquin River. Flooding on the San Joaquin generally impacts the west side of the County.

Increased storage will help reduce seasonal flood threats as well as the impact of larger incidents.

Climate Change Considerations
California’s Fourth Climate Assessment found that costs associated with direct climate change impacts by 2050 will be dominated by human mortality, coastal damage, and the potential for droughts and megafloods (CNRA 2018). Scientific studies outlined in the same assessment indicated shifts in California’s precipitation regime, which show more dry days, more dry years, a longer dry season, and increases in occasional heavy precipitation events and floods. Studies also project greater storm intensity with climate change, resulting in more direct runoff and flooding (CNRA 2018). As a result, high frequency flood events in conjunction with heavy precipitation events and extreme storm events will increase with climate change.

Certain climate studies noted in the Fourth Climate Assessment also forecast that during periods with heavy 949
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rain and frequent storm events there is an increase in flood events, as well as landslide and debris flow (CNRA 2018). Storms have historically resulted in many secondary hazards, including numerous landslides and in some watersheds an increased sediment load. Also, with wildfires already being a problem in California, increasing periods of drought and lack of precipitation are expected to exacerbate conditions for fires to occur, and in turn worsen the potential for runoff and flooding associated with burned areas.

The Fourth Climate Assessment also includes nine reports for the nine regions in California. According to the preview for the San Joaquin Valley Region Summary Report, the frequency of catastrophic floods will increase in the coming years. This in turn will lead to increased stresses to agriculture, natural ecosystems, water resources, land use and community development, transportation, energy, public health, and climate justice. Further, the 2022 Central Valley Flood Protection Plan includes a technical analysis on climate change with new projects on climate-related flood risk in the San Joaquin Valley. Communities throughout the Central Valley are threatened by current and future effects of climate change on hydrology, such as increases in precipitation falling as rain instead of snow at higher elevations, extreme precipitation events influenced by atmospheric rivers, and runoff events that are expected to exceed the State’s flood control system capacity (DWR 2022).

The 2022 CVFPP, which is the strategic blueprint for reducing Central Valley flood risk, highlights several impacts caused by climate change on flood risk in the Central Valley. Key risks summarized in the 2022 CVFPP included the number of people and structures at risk to flooding and economic damages in the Sacramento River Basin and the San Joaquin River Basin. For example, over a 50-year period (2022 through 2072) estimates of the annual lives lost more than doubles in the Sacramento River Basin and quadruples in the San Joaquin River Basin (DWR 2022). Also noted in the 2022 CVFPP is that socially vulnerable populations will bear a disproportionate share of adverse impacts of flooding, and research shows that recovery spending underserves these populations that need it the most. Poverty rates in Central Valley range from 10 percent to over 20 percent with higher poverty rates among children, seniors, Latinos, and less-educated adults (DWR 2022). This suggests that the socially vulnerable communities in the Central Valley face higher flood risk, particularly in the San Joaquin Valley. As mentioned in other sections of this plan, these communities often lack the resources to cope with and recovery from flood events without assistance.

The 2022 CVFPP integrates updated climate change analyses and a wider range of climate change projections to produce estimates of flood system performance at future points in time to provide flood managers with information on the potential impacts of climate change. Key findings from a technical analyses summary report that supports the 2022 CVFPP found that there will be increased warming across the planning area for all climate scenarios resulting in less below freezing temperatures, extreme precipitation is likely to intensify even with projections of overall drier conditions (this is the driver for most flood events and increase peak flows in winter and decrease flow in spring), and changes in flood magnitudes and frequencies of these events are projected to vary from the north to the south in the Central Valley (DWR 2022). Also, noted in the CVFPP is that watershed characteristics strongly influence the hydrological response to climate change, with the high-elevation San Joaquin watersheds showing the largest percentage increases in flood volumes because of a reduction in precipitation as snowfall and more rapid snowpack melting (DWR 2022). Additionally, during floods, reservoirs normally can release as much water as the downstream channels can safely accommodate. When inflows to a reservoir greatly exceed the reservoir storage capacity, dam safety concerns necessitate emergency operations to reduce storage and preserve the reservoir’s structural integrity (DWR 2022). In turn, the emergency releases may exceed the downstream capacity. In summary, because climate change hydrology analysis indicates that peak flows may increase throughout the system and the majority of the increased runoff comes from the upstream portions of the reservoirs in the Sierra Nevada, there is a need to mitigate future flood risk above, at, and below reservoirs; improve forecasting; expand storage; modify outlets; and increase downstream floodplain capacity to improve the flexibility of overall floodplain management.

Vulnerability Assessment
While there are some benefits associated with flooding, such as the replenishment of sediments and nutrients to agricultural lands, it is considered a hazard to development in floodplains. Floods can cause many cascading effects. Fire can break out as a result of dysfunctional electrical equipment. Hazardous 950
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materials can also get into floodways, causing health concerns and polluted water supplies. In many instances during a flood, the drinking water supply will be contaminated.

General Property
Historically, Stanislaus County has been at risk to flooding primarily during the winter and spring months when river systems swell with heavier rainfall and runoff from winter snowmelt. Normally, storm floodwaters are kept within defined limits by a variety of storm drainage and flood control measures. But occasionally, extended heavy rains result in floodwaters that exceed normal high-water boundaries and cause damage.

Flooding has occurred in the past within the 100-year floodplain and in other localized areas in the County.

A flood vulnerability assessment was performed for Stanislaus County using the following GIS methodology. The County’s parcel layer and associated assessor’s building improvement valuation data were provided by the County and were used as the basis for the inventory. Stanislaus County’s effective FEMA DFIRM dated August 24, 2021, was used as the hazard layer. A DFIRM is FEMA’s flood risk data that depicts the 1% annual chance (100-year) and the 0.2% annual chance (500-year) flood events; this data is incorporated into the National Flood Hazard Layer (NFHL). Figure 4-28 summarizes the flood zones included on these maps.

Stanislaus County Assessor Parcel data was used to estimate flood hazard impacts to parcels with improvement values greater than zero. The parcels are then converted to centroid points. This method assumes that improved parcels have a structure of some type. FEMA’s NFHL flood zones, with effective date August 24, 2021, were overlaid in GIS on the parcel centroid points to identify structures/parcels that would likely be inundated during a 1% annual chance and 0.2% annual chance flood event. This overlay is illustrated in Figure 4-28, and in more detail in the jurisdictional annexes.

Building improvement values and counts for those parcel centroid points were then extracted from the parcel/assessor’s data and summed for the unincorporated county and jurisdictions. Results of the overlay analysis area shown in Table 4-55 for the 1% annual chance flood and Table 4-56 for 0.2% annual chance flood. The jurisdictional annexes provide more detailed information based on assessor property types.

Property type refers to the land use of the parcel and includes Commercial, Industrial, Non-Assessable, Residential, Residential-Income, Rural Farm Agricultural, Unclassified, Vacant Commercial, and Vacant Residential. Contents values were estimated as a percentage of building values based on their occupancy type, using FEMA/Hazus estimated content replacement values. This includes 100% of the structure value for agricultural, commercial, non-assessable, and unclassified structures; 50% for residential structures; and 150% for industrial structures. Building and contents values were then totaled to obtain total exposure.

A loss estimate analysis was also performed based on depth damage functions developed by the Army Corp of Engineers and FEMA. The loss curves depict the expected flood losses associated with the depth of flooding at a structure. There are different depth damage curves for structure and content losses. For the purposes of this analysis, an average flood depth of two feet is assumed. A depth damage ratio of 25% was used for structural loss by multiplying it by the total values, based on the FEMA damage curves, assuming a 2-foot-deep flood. The results are shown in the loss estimate columns in Table 4-55 for the 1% annual chance flood and Table 4-56 for the 0.2% annual loss properties.

The result is an inventory of the number and types of improved parcels subject to flooding. Results are organized by unincorporated County and incorporated jurisdictions. Detailed tables show counts of parcels by jurisdictions and land use type (Commercial, Industrial, Non-Assessable, Residential, ResidentialIncome, Rural Farm Agricultural, Unclassified, Vacant Commercial, and Vacant Residential) within each flood zone. It is important to note that there could be more than one structure or building on an improved parcel (i.e., a condo complex occupies one parcel but might have several structures). The flood loss analysis does not account for business disruption, emergency services, environmental damages, or displacement costs, thus actual losses could exceed the estimate shown. Conversely, this analysis does not differentiate parcels that may have been developed since the County and cities adopted floodplain regulations, which would be mitigated to the 1% annual chance flood if developed in accordance with local floodplain regulations. Table 4-55 and Table 4-56 also do not include publicly-owned parcels that contain critical facilities and infrastructure; these vulnerable community lifelines are listed in Table 4-61 and Table 4-62.
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Table 4-55 1% Annual Chance Floodplain Exposure and Loss by Jurisdiction Jurisdiction Property Type Improved
Parcel Count Improved Value Estimated Content Value Total Value Estimated Loss Population Ceres
Commercial 2 $339,418 $339,418 $678,836 $169,709
Residential 1 $74,277 $37,139 $111,416 $27,854 4
Total 3 $413,695 $376,557 $790,252 $197,563 4
Modesto
Industrial 1 $3,453,683 $5,180,525 $8,634,208 $2,158,552 Residential 183 $30,649,630 $15,324,815 $45,974,445 $11,493,611 531 Residential-Income 1 $230,847 $115,424 $346,271 $86,568 3 Unclassified 2 $64,756 $64,756 $129,512 $32,378
Total 187 $34,398,916 $20,685,519 $55,084,435 $13,771,109 534 Newman
Commercial 92 $32,026,410 $32,026,410 $64,052,820 $16,013,205 Industrial 8 $5,700,420 $8,550,630 $14,251,050 $3,562,763 Residential 320 $33,974,723 $16,987,362 $50,962,085 $12,740,521 960 Residential-Income 15 $1,371,815 $685,908 $2,057,723 $514,431 45 Rural, Farm, Agricultural 1 $88,563 $88,563 $177,126 $44,282 Unclassified 16 $13,549,239 $13,549,239 $27,098,478 $6,774,620 Vacant Commercial 5 $22,113 $22,113 $44,226 $11,057
Vacant Residential 1 $75,308 $75,308 $150,616 $37,654
Total 458 $86,808,591 $71,985,532 $158,794,123 $39,698,531 1,005 Oakdale Residential 4 $1,264,652 $632,326 $1,896,978 $474,245 15 Total 4 $1,264,652 $632,326 $1,896,978 $474,245 15
Patterson
Commercial 15 $4,310,706 $4,310,706 $8,621,412 $2,155,353 Industrial 2 $469,751 $704,627 $1,174,378 $293,594
Residential 407 $54,926,055 $27,463,028 $82,389,083 $20,597,271 1,506 Residential-Income 8 $1,372,588 $686,294 $2,058,882 $514,721 30 Unclassified 10 $4,459,171 $4,459,171 $8,918,342 $2,229,586 Total 442 $65,538,271 $37,623,825 $103,162,096 $25,790,524 1,536 Unincorporated
Commercial 30 $10,183,097 $10,183,097 $20,366,194 $5,091,549 Industrial 20 $18,926,996 $28,390,494 $47,317,490 $11,829,373 Non-Assessable 2 $263,416 $263,416 $526,832 $131,708
Residential 586 $56,516,316 $28,258,158 $84,774,474 $21,193,619 1,811 Residential-Income 16 $1,746,832 $873,416 $2,620,248 $655,062 49 Rural, Farm, Agricultural 741 $153,219,040 $153,219,040 $306,438,080 $76,609,520 Unclassified 28 $5,042,104 $5,042,104 $10,084,208 $2,521,052 Vacant Commercial 2 $24,038 $24,038 $48,076 $12,019
Vacant Residential 3 $228,706 $228,706 $457,412 $114,353 Total 1,428 $246,150,545 $226,482,469 $472,633,014 $118,158,254 1,860 Grand Total 2,522 $434,574,670 $357,786,228 $792,360,898 $198,090,224 4,953 Source: Stanislaus County Assessor’s Office; NFHL Effective date 8/24/2008, FEMA; GIS analysis 952
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Significant areas of Stanislaus County are at risk of being inundated by a 100-year flood event. The City of Newman, City of Patterson, City of Modesto, and unincorporated areas of the County are predominantly inundated by the 100-year floodplain and have the greatest percentages of total loss from a 100-year flood event. While other jurisdictions are far less at risk during in a 100-year flood event, jurisdictions such as the City of Ceres and urban communities such as Westley and Crows Landing are at a great risk of inundation in the event of a 200-year flood.

Based on this analysis, the Stanislaus County Planning Area has 2,522 parcels valued at approximately $4.35 billion in the 100-year floodplain. An additional 7,610 parcels valued at over $1.55 billion within the 500-year floodplain. As a result, total structural exposure is approximately $5.9 billion. When factoring the content values within these areas in addition to the structures the total combined value of exposure is over $10.46 billion. Development in the 500-year floodplain is typically not regulated, thus a large flood event could be extremely damaging in the County. This information is summarized in Table 4-56 below. 953
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Table 4-56 0.2% Annual Chance Floodplain Exposure and Loss by Jurisdiction Jurisdiction Property Type Improved
Parcel Count Improved Value Estimated Content Value Total Value Estimated Loss Population Ceres
Residential 78 $8,714,394 $4,357,197 $13,071,591 $3,267,898 285 Total 78 $8,714,394 $4,357,197 $13,071,591 $3,267,898 285 Modesto
Commercial 16 $2,465,262 $2,465,262 $4,930,524 $1,232,631 Industrial 2 $589,725 $884,588 $1,474,313 $368,578
Residential 913 $121,250,154 $60,625,077 $181,875,231 $45,468,808 2,648 Residential-Income 11 $1,530,478 $765,239 $2,295,717 $573,929 32 Unclassified 92 $17,681,365 $17,681,365 $35,362,730 $8,840,683 Vacant Commercial 1 $17,288 $17,288 $34,576 $8,644
Total 1,035 $143,534,272 $82,438,819 $225,973,091 $56,493,273 2,680 Newman
Commercial 5 $1,519,026 $1,519,026 $3,038,052 $759,513
Industrial 11 $4,489,913 $6,734,870 $11,224,783 $2,806,196 Residential 514 $54,065,567 $27,032,784 $81,098,351 $20,274,588 1,753 Residential-Income 8 $753,826 $376,913 $1,130,739 $282,685 27 Unclassified 6 $1,093,880 $1,093,880 $2,187,760 $546,940 Vacant Commercial 2 $3,972 $3,972 $7,944 $1,986
Vacant Residential 1 $1,933 $967 $2,900 $725
Total 547 $61,928,117 $36,762,411 $98,690,528 $24,672,632 1,780 Oakdale
Commercial 8 $1,098,936 $1,098,936 $2,197,872 $549,468
Industrial 1 $143,252 $214,878 $358,130 $89,533
Residential 83 $18,463,874 $9,231,937 $27,695,811 $6,923,953 242 Unclassified 6 $821,866 $821,866 $1,643,732 $410,933
Total 98 $20,527,928 $11,367,617 $31,895,545 $7,973,886 242 Patterson
Commercial 103 $57,997,592 $57,997,592 $115,995,184 $28,998,796 Industrial 16 $5,830,284 $8,745,426 $14,575,710 $3,643,928 Residential 4,227 $871,169,044 $435,584,522 $1,306,753,566 $326,688,392 15,640 Residential-Income 47 $7,507,122 $3,753,561 $11,260,683 $2,815,171 174 Rural, Farm, Agricultural 14 $1,716,867 $1,716,867 $3,433,734 $858,434 Unclassified 39 $40,898,545 $40,898,545 $81,797,090 $20,449,273 954
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Jurisdiction Property Type Improved
Parcel Count Improved Value Estimated Content Value Total Value Estimated Loss Population Vacant Commercial 5 $118,338 $118,338 $236,676 $59,169
Vacant Residential 7 $13,847,070 $6,923,535 $20,770,605 $5,192,651 Total 4,458 $999,084,862 $555,738,386 $1,554,823,248 $388,705,812 15,814 Riverbank
Residential 210 $37,517,249 $18,758,625 $56,275,874 $14,068,968 722 Total 210 $37,517,249 $18,758,625 $56,275,874 $14,068,968 722 Waterford
Industrial 1 $27,971 $41,957 $69,928 $17,482
Residential 91 $24,377,622 $12,188,811 $36,566,433 $9,141,608 325 Residential-Income 1 $510,594 $255,297 $765,891 $191,473 4 Total 93 $24,916,187 $12,486,065 $37,402,252 $9,350,563 328 Unincorporated
Commercial 18 $5,279,230 $5,279,230 $10,558,460 $2,639,615 Industrial 28 $95,788,986 $143,683,479 $239,472,465 $59,868,116 Residential 637 $57,992,306 $28,996,153 $86,988,459 $21,747,115 1,968 Residential-Income 24 $2,116,727 $1,058,364 $3,175,091 $793,773 74 Rural, Farm, Agricultural 352 $86,047,521 $86,047,521 $172,095,042 $43,023,761 Unclassified 26 $6,586,064 $6,586,064 $13,172,128 $3,293,032 Vacant Commercial 3 $23,764 $23,764 $47,528 $11,882
Vacant Residential 3 $45,617 $22,809 $68,426 $17,106
Total 1,091 $253,880,215 $271,697,383 $525,577,598 $131,394,400 2,042 Grand Total 7,610 $1,550,103,224 $993,606,501 $2,543,709,725 $635,927,431 23,894 Source: Stanislaus County Assessor’s Office; NFHL Effective date 12/02/2008, FEMA; GIS analysis 955
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As mentioned in previous sections, in addition to FEMA 100-year and 500-year floodplains, a 200-year flood event based on the Comprehensive Study compiled by the USACE as well as a 100-year flood event layer compiled by DWR’s Awareness Floodplain Mapping project were acquired to assess flood vulnerability. Analyzing these floodplain data in the same way as described above revealed an estimate of 2,087 parcels with a total combined value of exposure at $603 million using the USACE 200-year flood event layer, and an estimate of 7,300 parcels with a total combined value of exposure at $2.49 billion, using the DWR 100-year flood event layer.

It is important to note that BAMs, which include the Comprehensive Study compiled by the USACE and DWR’s Awareness Floodplain Mapping project, do not replace existing FEMA regulatory floodplains, but rather identify potential flood risks that may warrant further studies or analysis.

Insurance Coverage, Claims Paid, and Repetitive Losses
Stanislaus County joined the NFIP in 1980; each jurisdiction also participates in the NFIP. Table 4-57 below shows the NFIP entry dates of Stanislaus County and its jurisdictions. Moreover, The City of Newman and City of Patterson currently participate in the Community Rating System (CRS). Both cities have a Class 9 and received 5% discount. The other jurisdictions and the County currently do not participate in the CRS.

Table 4-57 NFIP Entry Dates of Stanislaus County and Its Jurisdictions Jurisdiction NFIP Entry Date
Ceres March 7, 1997
Hughson April 21, 2020
Modesto August 15, 1980
Newman September 29, 1978
Oakdale September 5, 1979
Patterson August 1, 1979
Riverbank February 3, 1997
Stanislaus County August 1, 1980
Turlock May 14, 1981
Waterford July 16, 1979
In the unincorporated County, there are 303 flood insurance policies in force, of which there are 241 singlefamily units, 3 2-4 family units, zero in all other residential, and 59 non-residential. The number of policies in force by jurisdiction and flood zone are shown in Table 4-58. 956
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Table 4-58 Community Information System Policies in Force by Flood Zone and Jurisdiction Flood Zone Stanislaus
County
City of
Ceres
City of
Hughson
City of
Modesto
City of
Newman
City of
Oakdale
City of
Patterson
City of
Riverbank
City of
Turlock
City of
Waterford
A01-30 & AE
Zones 102 0 0 56 0 0 0 1 0 56
A Zones 52 0 0 0 1 0 0 0 0 0
AO Zones 26 0 0 0 52 0 5 0 0 0
AH Zones 7 0 0 0 2 0 92 0 0 0
atmospheric river
(AR) Zones 0 0 0 0 0 0 0 0 0 0
A99 Zones 0 0 0 0 0 0 0 0 0 0
V01-30 & VE
Zones 0 0 0 0 0 0 0 0 0 0
V Zones 0 0 0 0 0 0 0 0 0 0
D Zones 0 0 0 0 0 0 0 0 0 0
B, C & X Zone 0 0 0 0 0 0 0 0 0 0
Standard 30 0 0 20 2 0 17 0 1 0
Preferred 75 7 1 102 13 18 7 19 24 5
Total 292 7 1 178 70 18 121 20 25 61
Source: FEMA NFIP Community Information System
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NFIP data indicates that there are 890 insurance policies in Stanislaus County representing $223,896,900 of insurance coverage in force. Since 1978 there have been 230 paid losses, totaling $4,424,635. This results in approximately $102,898 in annualized losses. Most of the losses have been in the City of Modesto and the unincorporated County. Table 4-59 provides details on flood insurance policies for each individual jurisdiction.

FEMA insures properties against flooding losses through the NFIP. As part of the process to reduce or eliminate repetitive flooding to structures across the United States, FEMA has developed an official Repetitive Loss Strategy. The purpose behind the national strategy is to identify, catalog, and propose mitigation measure to reduce flood losses to the relatively few numbers of structures that absorb the majority of the premium dollars from the national flood insurance fund.

A repetitive loss property is defined by FEMA as “a property for which two or more NFIP losses of at least $1,000 each have been paid within any 10-year period since 1978”. A repetitive loss property may or may not be currently insured by the NFIP. There are eight repetitive loss buildings in the unincorporated County, one of which is insured and a total of $431,960 was paid out. Besides, there are also 18, 6 and 9 repetitive loss buildings in the Cities of Modesto, Newman, and Patterson. There are no Severe Repetitive Loss properties, as defined by FEMA, anywhere in the County.

Table 4-59 Stanislaus County Flood Insurance Policy Information Jurisdiction Policies Insurance in
Force
No. of Paid
Losses
Total Losses
Paid
Ceres 7 $2,025,000 0 $0
Hughson 1 $350,000 0 $0
Modesto 178 $50,016,000 50 $1,654,264
Newman 142 $35,034,400 27 $329,075
Oakdale 18 $6,300,000 0 $0
Patterson 191 $46,011,900 32 $274,891
Riverbank 20 $6,655,000 0 $0
Unincorporated Stanislaus County 303 $67,423,800 106 $2,121,232 Turlock 25 $8,330,800 14 $45,173
Waterford 5 $1,750,000 1 $0
Total 890 $223,896,900 230 $4,424,635
Source: FEMA NFIP Community Information System
People
The total people at risk were estimated by multiplying the average number of persons per household in Stanislaus County (3.09) and each applicable incorporated jurisdiction (Ceres 3.66, Hughson 3, Modesto

2.9, Newman 3.41, Oakdale 2.91, Patterson 3.7, Riverbank 3.44, Turlock 2.87, and Waterford 3.57) times the number of residential parcels in each floodplain to estimate the population residing in flood hazard areas.

Based on this analysis, which accounts for residents only and not workers, there are 4,953 residents living in the 100-year flood zone throughout the County. Of all study areas, the unincorporated County has the most residents living in the 1% annual chance flood area, followed by the City of Patterson. Table 4-60 below details population estimates by jurisdiction, followed a table for the 500-year floodplain.

Table 4-60 Population Living in the 1% Annual Chance Flood Hazard Zone Jurisdiction Population
Ceres 4
Modesto 534
Newman 1,005
Oakdale 15
Patterson 1,536
Unincorporated County 1,860
Total 4,953
Source: Wood GIS analysis on Stanislaus County Assessor’s Office data and FEMA NFHL, ACS Census Estimates 958
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The same analysis was conducted for the 500-year floodplain, indicating that there are 23,894 residents living in the 500-year flood zone throughout Stanislaus County. The majority of people living in this floodplain are residents of the City of Patterson, with 15,814 people in the 500-year floodplain. This population distribution is shown in the table below.

Table 4-61 Population Living in the 0.2% Annual Chance Flood Hazard Zone Jurisdiction Population
Ceres 285
Modesto 2,680
Newman 1,780
Oakdale 242
Patterson 15,814
Riverbank 722
Waterford 328
Unincorporated County 2,042
Total 23,894
Source: Wood GIS analysis on Stanislaus County Assessor’s Office data and FEMA NFHL, ACS Census Estimates Government Services
Publicly owned facilities are a key component of daily life for all citizens of the County. Public buildings are of particular importance during flood events because they house critical assets for government response and recovery activities. Damage to public water and sewer systems, transportation networks, flood control facilities, emergency facilities, and offices can hinder the ability of the government to deliver services. Loss of power and communications can be expected. Drinking water and wastewater treatment facilities may be temporarily out of operation. Flooding can have various impacts to responders in terms of response time and the personal safety of first responders. Flooded roadways are a common occurrence throughout the Planning Area and can block emergency vehicles from crossing certain areas, delaying response times.

Flood events can often result in motorists needing to be rescued from stalled vehicles in flooded roadways.

These types of challenges can often be dangerous for the first responders due to potentially polluted waters as well as swift currents.

Public confidence in government may be hindered if warnings and alerts prior to the flood event are not communicated effectively. Local governments’ ability to respond and recover may be questioned and challenged by the public if planning, response, and recovery is not timely and effective, particularly in areas that have repeated flooding.

Critical Facilities and Infrastructure
Key support facilities and structures most necessary to withstand the impacts of, and respond to, natural disasters are referred to as critical facilities. Examples of these critical facility types include utilities, transportation infrastructure, and emergency response and services facilities, given failures of components along major lifelines or even closures or inaccessibility to key emergency facilities could limit if not completely cut off transmission of commodities, essential services, and other potentially catastrophic repercussions. Floods and levee failure have the ability to disrupt, damage, or destroy these critical facilities, which in turn can impede the ability of Stanislaus County to respond to and recover from a major flood event.

A GIS analysis of exposed critical facilities was conducted, similar to the parcel analysis, using HIFLD. The results of critical facilities throughout the County which are exposed to the various flood hazards are shown in Table 4-62 and Table 4-63 below and organized by the jurisdiction they are located in and the FEMA Lifeline category into which they are classified.
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Table 4-62 Critical Facilities Within the 1% Annual Chance Flood Hazard by FEMA Lifeline and Jurisdiction
Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Ceres - - - - - - 1 1
Hughson - - - - - - - -
Modesto - - - 1 - 1 2 4
Newman - - - - - - - -
Oakdale - - - - - - - -
Patterson - - - - 1 - 3 4
Riverbank - - - - - - - -
Turlock - - - - - - - -
Waterford - - - - - - - -
Unincorporated 5 2 1 1 - - 38 47
Other Counties - - - - - - - -
Total 5 2 1 2 1 1 44 56
Source: HFILD, Stanislaus County, Cities of Newman, and Hughson Table 4-63 Critical Facilities Within the 0.2% Annual Chance Flood Hazard by FEMA Lifeline and Jurisdiction
Jurisdiction
CommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportationTotal Ceres - - - - - - - -
Hughson - - - - - - - -
Modesto 1 - - - 1 3 2 7
Newman 2 - 3 - - 2 - 7
Oakdale - - - - 1 - - 1
Patterson - - 3 - 4 10 4 21
Riverbank - - - - - - - -
Turlock - - - - - - - -
Waterford - - - - - - - -
Unincorporated 1 1 1 1 - - 5 9
Other Counties - - - - - - - -
Total 4 1 7 1 6 15 11 45
Source: HFILD, Stanislaus County, Cities of Newman, and Hughson Economy
Flooding can have a major economic impact on the economy. Based on the flood loss analysis, there are 2,397 commercial structures worth an estimated $771 million in total value directly at risk to flooding in the 1% annual chance zone. Based on the loss analysis this could result in approximately $193 million in direct losses. This does not account for other indirect losses such as business interruption, lost wages, and other downtime costs.
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Effects on the agriculture economy can be devastating, and a large amount of area at risk to flooding in the County is agricultural. Flooding can damage crops and livestock. In addition to the obvious impacts on crops and animals, flooding can have deleterious effects on soil and the ability to reinvigorate the agricultural activities impacted once the flood waters recede. Damage to water resources such as underground irrigation systems, water storage reservoirs, springs and other natural water bodies could have a serious effect upon agriculture operations.

Historic, Cultural, and Natural Resources
There are 28 properties throughout the County on the California Office of Historic Preservation Registry.

Seven of these places are located in the City of Modesto, while the southwestern portion of the Modesto has medium risk and exposure to flood hazards.

Natural areas within the floodplain often benefit from periodic flooding as a naturally recurring phenomenon.

These natural areas often reduce flood impacts by allowing absorption and infiltration of floodwaters.

Natural resources are generally resistant to flooding except where natural landscapes and soil compositions have been altered for human development or after periods of previous disasters such as drought and fire.

Wetlands, for example, exist because of natural flooding incidents. A large percentage of flood-prone area in the County are wetlands that are part of the San Joaquin River National Wildlife Refuge. These areas provide natural and beneficial functions to hold and absorb floodwaters. Areas recently suffering from wildfire damage may erode because of flooding, which can temporarily alter an ecological system.

Future Development
Flooding and floodplain management are significant issues for Stanislaus County. The potential or likelihood of a flood event in the County increases with the annual onset of heavy rains in winter and spring months. Much of the historical growth in the problem areas connected with flooding and stormwater runoff include erosion, sedimentation, degradation of water quality, losses of environmental resources, and certain health hazards. For NFIP participating communities, floodplain management practices implemented through local floodplain management ordinances should mitigate the flood risk to new development in the 100-year floodplains. As noted previously, a large amount of development has occurred in the 500-year floodplain and these areas are not regulated or require flood mitigation, thus flood risk is increasing to a degree, although to the less frequent flood events.

The development trend in the Stanislaus County Planning Area consists of steady growth. Much of this growth is occurring in the urban and SOI areas; such growth can result in more impervious surfaces due buildings and infrastructure and increase stormwater runoff.

The California DOF projects that Stanislaus County’s population will increase by 3.4% by the year 2025 when compared to the year of 2021. The County’s population will also continue to grow through the year 2060. Such growth may consume previously undeveloped acres, and the increase in impervious surfaces could affect existing drainage and flood control facilities.

Changes in municipal boundaries such as annexations into the SOI may change the flood risk profile for certain communities. A GIS analysis of 1% and 0.2% annual chance flood exposure within SOI boundaries is summarized in the tables below. These parcels are also included in Table 4-55 and Table 4-56, and they fall under “Unincorporated” in terms of their jurisdiction. Parcels shown below in Table 4-64 and Table 4-65 are those that fall within each jurisdiction’s SOI and are exposed to potential flood hazard events.

Table 4-64 Sphere of Influence Risk to FEMA 1% Annual Chance Flood Hazard Improved
Parcel
Count
Improved Value
Estimated
Content
Value
Total Value Population
Ceres 69 $16,701,108 $11,609,955 $28,311,063 209
Modesto 517 $53,218,689 $43,100,018 $96,318,707 1,351
Newman 20 $2,728,480 $2,399,329 $5,127,809 31
Patterson 19 $3,106,544 $1,929,618 $5,036,162 56
Total 625 $75,754,821 $59,038,920 $134,793,741 1,646
Source: Stanislaus County; Wood Analysis 2022
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Table 4-65 Sphere of Influence Risk to FEMA 0.2% Annual Chance Flood Hazard Jurisdiction
Improved
Parcel
Count
Improved Value Estimated
Content Value Total Value Population
Ceres 88 $20,524,430 $22,163,605 $42,688,035 271
Modesto 586 $136,459,520 $156,944,643 $293,404,163 1,491 Newman 39 $3,779,406 $2,226,945 $6,006,351 109
Oakdale 4 $257,958 $257,958 $515,916 -
Patterson 20 $1,920,068 $1,572,480 $3,492,548 19
Waterford 1 $7,664 $7,664 $15,328 -
Total 738 $162,949,046 $183,173,294 $346,122,340 1,889
Source: Stanislaus County; Wood Analysis 2022
Risk Summary
• The overall significance of the flood hazard in the County is Medium. • 12 flood events were recorded for Stanislaus County between 1950 and 2021, which means there is a 17% chance of a flood event occurring in a given year. Significant flooding also occurs in the County approximately every six years.
• Flooding risks are present among several creeks and rivers, including Del Puerto Canyon, Dry Creek, Orestimba Creek, Salado Creek, San Joaquin River, Stanislaus River, and the Tuolumne River. The Dry Creek watershed is a major factor in flooding in eastern Stanislaus County and the east side of Modesto.
• Scientific studies indicate shifts in California’s precipitation regime, which show more dry days, more dry years, a longer dry season, and increases in occasional heavy precipitation events and floods.

These same studies project greater storm intensity with climate change, resulting in more direct runoff and flooding and as a result, high frequency flood events in conjunction with heavy precipitation and extreme storm events.
• Key findings from the 2022 CVFPP included increased warming across the planning area for all climate scenarios, an intensification of extreme precipitation even with projections of overall drier conditions, and changes in flood magnitudes and frequencies that are projected to vary from the north to the south in the Central Valley.
• When inflows to reservoirs exceed the reservoir storage capacity, dam safety concerns necessitate emergency operations to reduce storage and preserve reservoirs structural integrity. This means that emergency releases may exceed the downstream capacity and the need to mitigate future flood risk above and below reservoirs; improve forecasting; and increase downstream floodplain capacity to improve the flexibility of overall floodplain management. • Countywide there are 10,132 structures at risk within the limits of the 100-year and 500-year floodplain zones worth over $3.33 billion, with a loss estimate of over $0.83 billion. • The unincorporated County accounts for 59.6% of the total estimated losses in the 100-year floodplain; City of Patterson accounts for 61.1% of the total losses in the 500-year floodplain. • Commercial structures account for 34.5% of total losses in the 100-year floodplain, with a loss estimate of $68.3M.
• Countywide approximately 4,953 persons live in the 100-year floodplain, of which the vast majority (1,860) are in the unincorporated County.
• There are 23,894 persons within the 500-year floodplain and a flood of this magnitude would have severe consequences.
• Levees and flood control dam infrastructure provide some protection, but also pose potential levee and dam failure risks.
• A total of 56 critical facilities are found in 1% annual chance and 55 critical facilities are in the 0.2% annual chance flood zones in the County.
• Related hazards – Severe weather: Heavy Rain, Wildfire, Landslide and Debris Flow. 962
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Table 4-66 Hazard Risk Summary – Flood
Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Significant Likely Critical Medium Yes City of Ceres Limited Likely Negligible Low No
City of Hughson Limited Likely Negligible Medium No
City of Modesto Significant Likely Limited Medium Yes
City of Newman Significant Likely Critical Medium Yes
City of Oakdale Limited Likely Negligible Medium Yes
City of Patterson Significant Likely Catastrophic High Yes City of Riverbank Limited Likely Negligible Low Yes
City of Turlock Limited Likely Negligible Low No
City of Waterford Limited Likely Negligible Low No
County Office of Education Significant Likely Negligible Low Yes

4.3.9 Landslide
Hazard Problem/Description
According to the USGS National Landslide Information Center (NLIC), the term “landslide” is defined as the movement of a mass of rock, debris, or earth down a slope. The force of gravity acting upon a steep (or sometimes, even a moderately steep) slope is the primary cause of a landslide. Slope failure occurs when the force of gravity pulling the slope downward exceeds the strength of the earth materials that comprise the slope to hold it in place. In addition to the force of gravity, other contributing factors to landslides can include rainfall, earthquakes, changes in groundwater, and human-induced modifications to existing slopes.

The potential for a landslide to occur exists in every state wherever very weak or fractured materials are resting on a moderate to steep slope.

The severity of a landslide depends in large part on the degree of development in the area in which it occurs and the geographic area of slide itself. Generally speaking, landslides often result in devastating consequences, but in very localized areas. A landslide occurring in an undeveloped area would be less severe because lives and property would not be affected; the only impacts would be to land, vegetation, and possibly some wildlife. On the contrary, a landslide occurring in a developed area could have devastating effects, ranging from structure and infrastructure damage to injury and/or loss of life. Structures or infrastructure built on susceptible land would likely collapse as their footings slide downhill, while those below the land failure would likely be crushed. Landslides around roadways could have the potential to fall and damage or destroy vehicles and force other drivers to have accidents.

Mudslides are a mass of water and fine-grained earth that flows down a stream, ravine, canyon, arroyo, or gulch. If more than half of the solids in the mass are larger than sand grains (rocks, stones, boulders), the event is called a debris flow. A debris fan is a conical landform produced by successive mud and debris flow deposits, and the likely spot for a future event. Mud and debris flow problems can be exacerbated by wildfires that remove vegetation that serves to stabilize soil from erosion. Heavy rains on the denuded landscape can lead to rapid development of destructive mudflows.

A rockfall is the falling of a detached mass of rock from a cliff or down a very steep slope. Weathering and decomposition of geological materials produce conditions favorable to rockfalls. Rockfalls are caused by the loss of support from underneath through erosion or triggered by ice wedging, root growth, or ground shaking. Changes to an area or slope such as cutting, and filling activities can also increase the risk of a rockfall. Rocks in a rockfall can be of any dimension, from the size of baseballs to houses. Rockfalls can threaten human life, impact transportation corridors and communication systems and result in other property damage. Rockfalls and landslides are influenced by seasonal patterns, precipitation, and temperature patterns. Earthquakes could trigger rockfalls and landslides too.

There are predictable relationships between local geology and landslides, rockslides, and debris flows. The downslope movement of earth material, either as a landslide, debris flow, mudslide, or rockslide, is part of 963
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the continuous, natural process of erosion. This process, however, can be influenced by a variety of causes that change the stability of the slope. Slope instability may result from natural processes, such as the erosion of the toe of a slope by a stream, or by ground shaking caused by an earthquake. Slopes can also be modified artificially by grading, or by the addition of water or structures to a slope. Development that occurs on a slope can substantially increase the frequency and extent of potential slope stability hazards.

Knowledge of these relationships can improve planning and reduce vulnerability. Slope stability is dependent on many factors and their interrelationships, including rock type, moisture content, slope steepness, and natural or manmade undercutting.

Geographic Area
Significant – Hazards due to landslide events are mostly limited to areas within the foothills at the western and eastern edges of Stanislaus County. The western edge of the County is part of the Diablo Range which stretches almost 200 miles along the west side of the Central Valley, running parallel to the Pacific Ocean.

Virtually the entire area located west of Interstate 5 is composed of geological formations that, due to structure, slope, runoff, lack of vegetation, earthquake, and human activity, are considered extremely susceptible to failure and sliding. This is also mentioned in the County’s General Plan’s Safety Element.

The eastern edge of the runs parallel to the Sierra Nevada Mountain range. The west-facing slope of the Sierra Nevada range has a series of streams whose waters ultimately reach the Pacific Ocean. It is along these areas and other locally identified specific river bluff regions near rivers and streams that are susceptible to landslide, though there are few past occurrences. The areas near rivers and streams are also subject to natural erosion, although erosion activity may be increased during flood events. Deep-seated landslide susceptibility in the County is depicted in Figure 4-29. 964
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Figure 4-29 Stanislaus County Deep-Seated Landslide Susceptibility 965
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Extent (Magnitude/Severity)
Negligible – Figure 4-30 shows the relative extent of deep land sliding based on regional estimates of rock strength and steepness of slopes. The data used for the map utilizes detailed information on the location of past landslides, the location and relative strength of rock units, and steepness of slope in a methodology developed by Wilson and Keefer (1985) as implemented by Ponti et al (2008) to create classes of landslide susceptibility. These classes express the generalization that on very low slopes, landslide susceptibility is low even in weak materials, and that landslide susceptibility increases with slope and in weaker rocks. The convergence of factors suggests limited landslide potential in most of Stanislaus County due to the very low slopes. There are areas on the west side where the potential increases due to increase in slope and topography along the Diablo Range to the west and the Sierra Nevada range to the east these areas are shown in red in Figure 4-30.

Landslides are often triggered by other natural hazards such as earthquakes, heavy rain, flood, or wildfires.

Landslide frequency is often related to the frequency of these other hazards. In Stanislaus County, landslides typically occur during and after major storms so the potential for landslides largely coincides with the potential for sequential severe storms that saturate steep, vulnerable soils. In the winter of 1982-1983, saturation of the soil in the Diablo Range area resulted in a considerable amount of damage to Del Puerto Canyon Road. During the winter storms of 1997, Del Puerto Canyon Road experienced an approximately 10-mile landslide consisting of mud, rocks and boulders. One lane was closed for repair for 2 to 3 months while the other lane stayed open to traffic. This caused minor traffic delays since the road is not a major thoroughfare. These types of landslides are typical for this area following storms due to vertical cuts for roadways without sufficient sloping for runoff.

Previous Occurrences
There have not been any disaster declarations associated with landslides in Stanislaus County. According to records from the California Geological Survey (CGS), there has been one recent record of landslide that occurred in 2017.

January 10, 2017 – Highway 132 was covered in rock, which resulted in road closure. The location is just under one mile west of the intersection of Highway 132 and La Grange Road. According to Stanislaus Count 2017 LHMP, this landslide event was one of the two landslides occurred at the location. This landslide consisted of rocks and boulders and closed one lane for about 3 hours while Caltrans removed the debris. The slides were 10 to 15 feet on the roadway. and boulders and caused minor traffic delays. Cleanup was completed within 1 to 2 hours and the road was fully open for traffic.

Moreover, the County’s 2017 LHMP noted that the storms of January 2017 created landslides across Del Puerto Canyon Road ranging from 3 feet to 40 feet in size. These slides consist of mud, rocks and boulders and caused minor traffic delays. In addition, a significant rain event in January 2016 required one lane closure of Del Puerto Canyon Road, which caused minimum impact to traffic.

Probability of Future Occurrences
Occasional – It is evident that the steep slopes and undesirable geology of the area on the west side of the County, even without considering the possibility of an earthquake, present risks in certain conditions. It is common for minor incidents requiring some debris clearing of Del Puerto Canyon Road to occur on average of 5 to 12 times a year. On the east side of the County there are frequent landslides on Highway 132 along the river bluffs. These landslides are usually due to rain and occur during or within days after a storm. Based on these past events, landslides are high frequency events and highly likely to continue to impact the Diablo Range and areas on Hwy 132 but are limited to occasional events in the central portion of the County.

Highway 132 covered in rock
during the January 10, 2017
landslide event.

Photo credit: Caltrans District 10
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The CGS uses three factors that most determine susceptibility of landslide: prior failure, rock or soil strength, and steepness of slope. Landslides can also be triggered by rainfall, earthquake shaking, or other factors.

The unstable formation comprising the underlying geologic structure of the Diablo Range then makes this area of Stanislaus County more vulnerable to landslides and its effects. The few structures and population within the Diablo Range are most vulnerable to damage due to landslides.

Impacts in the Diablo Range, specifically Del Puerto Canyon Road, are limited. Del Puerto Canyon Road is not a major thoroughfare, and the area is sparsely populated. There are no critical buildings in the area.

Stanislaus County Public Works maintains the road and within 1-2 hours, debris is cleared with little to no impact to traffic. The staffing and equipment needed to clear the landslide are minimal. Therefore, the impacts of landslides on the population have been minimal due to the short duration of road closure during debris removal. Moreover, the landslides experienced on Highway 132 are also limited occurring due to rain and during or within days after a storm. These happen along the river bluff and there are no critical structures in the area. Roadways may be blocked causing traffic delays.

Climate Change Considerations
Landslides can result from intense rainfall and runoff events. Projected climate change-associated variance in rainfall events may result in more high-intensity events, which may increase landslide frequency. In addition, the increased potential of wildfire occurrence also escalates the risk of landslide and debris flows in the period following a fire, when slopes lack vegetation to stabilize soils and burned soil surfaces create more rainfall runoff. As climate change affects the length of the wildfire season, it is possible that a higher frequency of large fires may occur into late fall, when conditions remain dry. The wildfires can be followed by intense rains early in the winter, as occurred with the Thomas Fire in December 2017 and subsequent Montecito and Carpinteria debris flows in January 2018 that occurred in Santa Barbara County (CA SHMP 2018). Moreover, tree mortality resulting from drought, pests or any other threat could also pose an increase to landslides. Currently, Stanislaus County is not experiencing tree mortality as severe as other areas of California due to the drought and bark beetle. However, any future loss of trees would reduce the protection of steep slopes and thereby increase the probability for landslide occurrences.

Vulnerability Assessment
General Property
Landslides directly damage engineered structures in two general ways: 1) disruption of structural foundations caused by differential movement and deformation of the ground upon which the structure sits, and 2) physical impact of debris moving downslope against structures located in the travel path.

During the 2021 update of this plan, a GIS analysis of exposure to landslide hazard areas was performed.

GIS analysis indicates approximately $63.4 billion of property improvements are exposed, which takes into account improved values of properties. Table 4-67 summarizes landslide exposure by jurisdiction. GIS was used to intersect the parcel boundaries with a master address point layer to obtain the number of buildings per parcel. Only parcels with improvement values greater than zero were used in the analysis, this method assumes that improved parcels have a structure of some type.

Based on this analysis there is a total of 2,864 improved parcels potentially within landslide hazard areas.

The majority of this exposure is in the western unincorporated County. There is a high level of uncertainty as to the actual risk to these exposed parcels, thus a more specific loss estimation is not provided. A more detailed, site specific analysis would be needed to assess actual risk within the identified parcels.

Table 4-67 Stanislaus County Improved Properties at Risk to Landslide Jurisdiction Improved
Parcel Count Improved Value Estimated Content Value Total Value Population Ceres 23 $11,571,650 $12,087,387 $23,659,037 77
Hughson - - - - -
Modesto 369 $96,766,751 $54,390,827 $151,157,578 1,032
Newman 8 $1,834,671 $917,336 $2,752,007 27
Oakdale 429 $104,345,400 $69,518,643 $173,864,043 1,190 Patterson 2 $87,037 $87,037 $174,074 0
Riverbank 77 $18,661,965 $11,728,810 $30,390,775 241
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Jurisdiction Improved
Parcel Count Improved Value Estimated Content Value Total Value Population Turlock - - - - -
Waterford 149 $31,727,856 $17,491,408 $49,219,264 464
Unincorporated 1,807 $547,149,003 $457,888,713 $1,005,037,716 1,687 Total 2,864 $812,144,333 $624,110,159 $1,436,254,492 4,719 Source: Department of Conservation, CGS, Stanislaus County Assessor, Wood GIS Analysis Figure 4-30 below further breaks down the numbers of exposed parcels by landslide class, as shown previously in Figure 4-29; the higher the class the greater the susceptibility.

Figure 4-30 Total Parcel Counts by Landslide Class
Source: Dept. of Conservation, CGS, Stanislaus County Assessor, Wood GIS Analysis People
People could be susceptible if they are caught in a landslide or debris flow, potentially leading to injury or death. There is also a danger to drivers operating vehicles, as rocks and debris can strike vehicles passing through the hazard area or cause dangerous shifts in roadways. The parcel analysis described previously estimated there are approximately 4,719 people potentially residing in landslide susceptible areas, but it is not likely that landslides will occur without warning and direct impacts to people are suspected to be minimal.

Government Services
Aside from possible damage to government facilities, the impact of landslides and rockslides on government services or public confidence in government is minimal. The vulnerability of responders to landslide and rockslide events is similar to that of the general public.

Critical Facilities and Infrastructure
In addition to buildings, utilities and transportation structures are vulnerable to the impact and ground deformation caused by slope failures. They present a particular vulnerability because of their geographic extent and susceptibility to physical distress. Lifelines are generally linear structures that, because of their geographic extent, have a greater chance of being affected by ground failure due to greater hazard exposure.
0 500 1,000 1,500 2,000 2,500 3,000 3,500
Class 3 Parcel Count
Class 5 Parcel Count
Class 6 Parcel Count
Class 7 Parcel Count
Class 8 Parcel Count
Class 9 Parcel Count
Class 10 Parcel Count
Total Building Count
Parcel Counts
Landslide Class
Total Parcel Counts by Landslide Class
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Extension, bending, and compression caused by ground deformation can break lifelines. Failure of any component along the lifeline can result in failure to deliver service over a large region. Once broken, transmission of the commodity through the lifeline ceases, which can have catastrophic repercussions including loss of power to critical facilities such as hospitals, impaired disposal of sewage, contamination of water supplies, disruption of all forms of transportation, and release of flammable fuels. Therefore, the overall impact of lifeline failures, including secondary failure of systems that depend on lifelines, can be much greater than the impact of individual building failures.

Table 4-68 below summarizes the results of the critical facilities analysis, highlighting the exposure of critical facilities throughout the County to landslide hazards. Many exposed critical facilities are located in unincorporated areas of the County, largely to the west of Interstate 5.

Table 4-68 Critical Facilities Within the Class 9 Landslide Hazard by FEMA Lifeline Jurisdiction
LandslideClassCommunicationsEnergyFood, Water, ShelterHazardous MaterialHealth and MedicalSafety and SecurityTransportation Total
Ceres 10 1 1
7 2 2
Modesto
10 3 3
9 1 - - - - 5 6
7 1 - - - - 5 6
Patterson 8 - 1 - - - 1
10 1 1
Riverbank 9 1 1
7 1 1 2
Turlock 7 1 1 2
Unincorporated
10 3 1 - - - 10 14
9 - - 1 - - - 10 11
8 2 2 - - - - 3 7
7 - 1 1 1 - 2 39 44
6 - 2 - - - - - 2
5 12 1 - - - 2 10 25
3 - - - 1 - - 1 2
Total 19 8 4 3 1 4 91 130
Source: CGS, HIFLD, Wood GIS Analysis
Moreover, as noted in the County’s 2017 HMP, several State highways traverse cuts through hillsides or along river bluffs where landslide hazards may pose a risk, including State Routes (SRs) 4, 108, 120, 132, 219 and Interstate 5. County roads at risk are shown in Table 4-69 below:

Table 4-69 County Roads Susceptible to Landslide Hazards County Roads at Risk
Del Puerto Canyon Road
Crows Landing Road (at San Joaquin River)
Grayson Road (at San Joaquin River)
Lake Road
Mitchell Road (at Tuolumne River)
River Road (Ceres Area)
Shiloh Road (at Tuolumne River)
Diablo Grande Parkway
Cooperstown Road
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County Roads at Risk
Geer/Albers Roads
La Grange Road
Orestimba Road
Roberts Ferry Road
South Carpenter Road
Crabtree Road
Hills Ferry Road
Ingram Creek Road
Los Cerritos Road
Paradise Road (at San Joaquin River)
Santa Fe Avenue
Warnerville Road
Source: Stanislaus Count 2017 HMP
Economy
Economic impacts typically center around transportation routes temporarily closed by debris flow or landslide activity. These roads may be used to transport goods across the County or provide access by visitors and tourists. Depending on the amount of damage, the road may simply need to be cleaned off, or may require some level of reconstruction.

Historic, Cultural, and Natural Resources
As primarily a natural process, landslides and debris flows can have varying impacts to the natural environment; debris flows have the potential to permanently alter the natural landscape. The impacts of landslides and debris flows on historical and cultural structures would be similar to the impacts on general property.

Future Development
The severity of landslide problems is directly related to the extent of human activity in hazard areas. Human activities such as property development and road construction can also exacerbate the occurrence of landslides. Future development should take place carefully to prevent landslide damage to property or people. Adverse effects can be mitigated by early recognition and avoiding incompatible land uses in these areas or by corrective engineering. Improving mapping and information on landslide hazards and incorporating this information into the development review process could prevent siting of structures and infrastructure in identified hazard areas.

A GIS analysis of exposure to landslide hazard within SOI boundaries is summarized in the tables below.

These parcels are also included in Table 4-67, and they fall under “Unincorporated” in terms of their jurisdiction. Parcels shown below in Table 4-70 are those that fall within each jurisdiction’s SOI and are exposed to potential landslide hazard events.

Table 4-70 Sphere of Influence Risk to Landslide Hazard Jurisdiction
Improved
Parcel
Count
Improved Value Estimated
Content Value Total Value Population
Ceres 81 $17,105,613 $9,848,189 $26,953,802 260
Modesto 62 $7,173,488 $5,785,965 $12,959,453 157
Oakdale 76 $13,383,107 $8,886,713 $22,269,820 160
Riverbank 49 $13,373,065 $6,713,824 $20,086,889 165
Waterford 5 $915,670 $915,670 $1,831,340 0
Total 273 $51,950,943 $32,150,360 $84,101,303 742
Figure 4-31 below further breaks down the numbers of exposed parcels within SOI areas by landslide class. 970
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Figure 4-31 Total Parcel Counts within SOI areas by Landslide Class There has been limited development in the Diablo Grande area, which is located seven miles west of I-5.

The development was approved by the Board of Supervisors in 1993 for 5,000 residences. However, because of the economic turn down in 2008, build out of the residential area was stalled. There are currently 425 occupied residences while building development is projected to continue over the next few years. Aside from the limited development in the Diablo Grande area, there has been no significant change in development in the unincorporated areas impacted by landslide within Stanislaus County since the last LHMP update.

Construction is possible west of Interstate 5, but any proposals for significant development (anything other than the currently permitted two dwellings for every 160 acres), should include a geological report identifying potential problems and mitigation measures to be incorporated into the development plan. The County also complies with the CEQA process to ensure that development does not occur that would be especially susceptible to landslides. Most discretionary projects require review for compliance with CEQA. As part of this environmental review, potential impacts must be identified and mitigated or a statement of overriding concerns adopted. Further, the routes of new public roads in areas subject to landslides shall be designed to minimize landslide risks. Engineered benchmarks will be utilized to monitor movement of slopes to stabilize and mitigate the hazard before it occurs, if possible. Also, road-clearing and debris equipment must be pre-staged to make response time faster to maintain accessibility to roads and infrastructure.

Improved mapping and data collection will assist in identifying needed mitigation strategies for the future.

Risk Summary
• The overall significance of landslides in Stanislaus County is Low. • The geologic formations commonly associated with slope stability problems in Stanislaus County, are largely concentrated in the far western and eastern edges of the County, which are also the least populated.
• On the west side of the County minor landslide incidents and debris clearing occurs along Del Puerto Canyon Road on average of 5 to 12 times a year. On the east side there are frequent landslides on Highway 132 along the river bluffs. These landslides are due to rain and occur during or within days after a storm. Based on these past events, landslides are high frequency events and highly likely to continue to impact the Diablo Range and areas along Hwy 132 but are only occasional events in the central portion of the County.
• Effects on people – People are most commonly at risk if they are caught in a landslide or debris flow, including when driving through a hazard area.
• Effects on property – Property loss is rare, but GIS analysis shows there is some property which could be exposed to landslides.
0 20 40 60 80 100 120 140 160 180 200
Class 5 Parcel Count
Class 7 Parcel Count
Class 9 Parcel Count
Class 10 Parcel Count
Parcel Counts
Landslide Class
Total Parcel Counts by Landslide Class
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• Effects on economy – Landslides in adjacent counties can disrupt major transportation corridors, possibly affecting the local tourist economy and shipment of goods. • Effects on critical facilities and infrastructure – Landslides and debris flows can result in the destruction of infrastructure such as water and sewer lines, electrical and telecommunications utilities and drainage. Disrupted transportation routes occur occasionally, usually during heavy rainstorms, and cause considerable inconvenience.
• Related Hazards – Earthquake, Adverse Weather, Wildfire.

Table 4-71 Hazard Risk Summary – Landslides
Jurisdiction Geographic
Area
Probability of
Future
Occurrence
Magnitude/
Severity
Overall
Significance
Priority
Hazard?
Stanislaus County Significant Occasional Negligible Low No City of Ceres Limited Occasional Negligible Low No
City of Hughson Limited Occasional Negligible Low No
City of Modesto Limited Occasional Negligible Low No
City of Newman Limited Occasional Negligible Low No
City of Oakdale Limited Occasional Negligible Low No
City of Patterson Limited Occasional Negligible Low No
City of Riverbank Limited Occasional Negligible Medium Yes City of Turlock Limited Occasional Negligible Low No
City of Waterford Limited Occasional Negligible Low No
County Office of Education Significant Occasional Negligible Low No

4.3.10 Public Health Hazards: Pandemics/Epidemics
Hazard/Problem Description
A pandemic can be defined as a disease that attacks a large population across great geographic distances.

Pandemics are larger than epidemics in terms of geographic area and the number of people affected.

Epidemics tend to occur seasonally and affect much smaller areas. Pandemics, on the other hand, are most often caused by new subtypes of viruses or bacteria for which humans have little or no natural resistance. Consequently, pandemics typically result in more deaths, social disruption, and economic loss than epidemics.

Three conditions trigger a pandemic declaration:

1. A new virus subtype must emerge that has not previously circulated in humans (and therefore there is no pre-existing immunity),

2. This new subtype must be able to cause disease in humans, and

3. The virus must be easily transmissible from human-to-human.

Since March 2020, Stanislaus County, the nation, and the world are dealing with the public health hazards, specifically the COVID-19 pandemic (caused by the SARS-CoV-2 virus). The COVID-19 pandemic confirms that pandemic is a key public health hazard in the Planning Area. This hazard risk assessment includes an analysis of pandemic and infectious disease risk across Stanislaus County and an analysis of the impacts of the hazards profiled in this plan on public health.

COVID-19
Unlike seasonal flu, a pandemic has much greater potential for loss of life and significant social disruption due to higher rates of transmission and more severe health impacts. The SARS-CoV-2 virus has a much higher rate of transmission than the seasonal flu, primarily by airborne transmission of droplets/bodily fluid.

Common symptoms include fever, cough, fatigue, shortness of breath or breathing difficulties, and loss of smell and taste. While most people have mild symptoms, some people develop acute respiratory distress syndrome with roughly one in five requiring hospitalization in the United States and a fatality rate between 1 to 2 percent. Because the virus can be transmitted by people who are asymptomatic, and due to the 972
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presence of several variants of SARS-CoV-2, the Delta and Omicron Variant, for example, containing the spread has been a significant challenge across the globe.

Valley Fever
Another example of a human health hazard that is endemic to Stanislaus County is Valley Fever, or “cocci” which is a known but poorly understood secondary effect of drought conditions, and possibly a combination of wind and drought events followed by a rainy season. Valley Fever is an infection caused by a fungus (Coccidioides immitis) that lives in soil and dirt and areas with low rainfall, high summer temperatures, and moderate winter temperatures. Valley Fever is primarily a disease of the lungs and the infection can occur year-round. In California, it has been reported from most counties, but especially from the San Joaquin Valley and Central Coast. Anyone who lives in, works in, or visits a place with Valley Fever can be infected.

Figure 4-34 below shows Valley Fever Annual Incidence among California Counties in the year 2012 – 2016 and 2017. People can get sick by breathing in a form of the Valley Fever fungus called spores. Spores are too small to be seen and they can get into the air with dust when it is windy or when dirt is distributed.

Fortunately, Valley Fever cannot be spread from one person to another. About 60% of infected people will not get sick. People who do get sick can have symptoms such as fever, tiredness, and weight loss that last a month or more. Valley Fever can also infect the brain, joints, bone, skin, or other organs. This type of infection is rare; however, it can be serious and sometimes fatal. Most people who get Valley Fever fully recover and are usually protected from getting Valley Fever again (CDPH 2021).

Geographic Area
Extensive – Pandemics occur not only on a county or state level but on a national and global scale. It is likely that most communities in Stanislaus County would be affected, either directly or by secondary impacts. Some indirect consequences may be the diversion of resources that may be otherwise available.

Stanislaus County has reported 84,433 cases and 1,302 deaths from COVID-19 as of October 12, 2021.

According to the Los Angeles Times “Tracking the coronavirus in Stanislaus County” dashboard, the major cities of Stanislaus have the highest number of cases, which is around 1,038 to 1730 cases per 10,000 residents, among which the City of Ceres currently has the highest concentration of cases (approximately 1,557 – 1,730 cases per 10,000 residents), as of October 12, 2021. These major cities like Ceres and Modesto have higher populations and municipal areas relative to other urban communities within the County, and COVID-19 is transmitted primarily from human-to-human contact. Figure 4-32 below shows the cases per 10,000 residents map for the cities in Stanislaus County, prepared by Los Angeles Times. 973
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Figure 4-32 Coronavirus cases per 10,000 residents for cities in Stanislaus County Data source: Los Angeles Time, October 12, 2021
Figure 4-33 shows Valley Fever rates by California county. Figure 4-34 shows Valley Fever (coccidioidomycosis) cases by zip code per 100,000 population for Stanislaus County between 2014 and 2017. Figure 4-35 shows the reported cases of Valley Fever by year in Stanislaus County from 2011 – 2017.
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Figure 4-33 Valley Fever Rates in California Counties, 2012 – 2016 & 2017 Source: CDPH, November 2018.
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Figure 4-34 Valley Fever Cases by Zip Code per 100,000 population, Stanislaus County, 2014 and 2017
Source: CDPH, Stanislaus County Health Services Agency, December 2017.

Figure 4-35 Reported cases of Valley Fever by year, Stanislaus County from 2011 – 2017 Source: 2018 Stanislaus County Public Health Annual Report Extent (Magnitude/Severity)
Critical – The magnitude of a public health emergency will range significantly depending on the transmissivity and mortality rate of the virus. For example, pandemic influenza is easily transmitted from person-to-person, however, advances in medical technologies have greatly reduced the number of deaths caused by influenza over time.
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Today, a much larger percentage of the world’s population is clustered in cities, making them ideal breeding grounds for epidemics. Additionally, the explosive growth in air travel means the virus could spread around the globe within hours. Under such conditions, there may be very warning little time for counties, states, and countries to prepare. Most experts believe we will have just one to six months between the time that a dangerous new influenza strain is identified and the time that outbreaks begin to occur in the United States.

Outbreaks are expected to occur simultaneously throughout much of the nation, preventing shifts in human and material resources that normally occur with other natural disasters. These and many other aspects make pandemics unlike any other public health emergency or community disaster. Pandemics typically last for several months to 1-2 years and have even longer-lasting effects on the economy and communities.

As described by the World Health Organization (WHO), the Pandemic Intervals Framework (PIF) is a sixphased approach to defining the progression of a pandemic. This framework is used to guide pandemic planning and provides recommendations for risk assessment, decision-making, and action. These intervals provide a common method to describe a pandemic activity that can inform public health actions. The duration of each pandemic interval might vary depending on the characteristics of the virus and the public health response.

The six-phase approach was designed for the easy incorporation of recommendations into existing national and local preparedness and response plans. Phases 1 through 3 correlates with preparedness in the prepandemic interval, including capacity development and response planning activities, while Phases 4 through 6 signal the need for response and mitigation efforts during the pandemic interval. Phase 6 was reached in the County during the 2020 COVID-19 outbreak.

Pre-Pandemic Interval
Phase 1 is the natural state in which influenza viruses circulate continuously among animals but do not affect humans.

Phase 2 involves cases of animal influenza that have circulated among domesticated or wild animals and have caused specific cases of infection among humans.

Phase 3 represents the mutation of the animal influenza virus in humans so that it can be transmitted to other humans under certain circumstances (usually very close contact between individuals). At this point, small clusters of infection have occurred.

Pandemic Interval
Phase 4 involves community-wide outbreaks as the virus continues to mutate and become more easily transmitted between people (for example, transmission through the air).

Phase 5 represents human-to-human transmission of the virus in at least two countries.

Phase 6 is the pandemic phase, characterized by community-level influenza outbreaks.

Past Occurrences
Since the early 1900s, five lethal pandemics have swept the globe:
• 1918-1919 Spanish Flu – The Spanish Flu was the most severe pandemic in recent history. The number of deaths was estimated to be 50-100 million worldwide and 675,000 in the United States. Its primary victims were mostly young, healthy adults. At one point, more than 10 percent of the American workforce was bedridden.
• 1957-1958 Asian Flu – The 1957 Asian Flu pandemic killed 1 to 2 million people worldwide, including about 70,000 people in the United States, mostly the elderly and chronically ill. Fortunately, the virus was quickly identified, and vaccine production began in May 1957. • 1968-1969 H3N2 Hong Kong Flu – The 1968 Hong Kong Flu pandemic killed 34,000 Americans.

Again, the elderly were more severely affected. This pandemic peaked during school holidays in December, limiting student-related infections, which may have kept the number of infections down.

Also, people infected by the Asian Flu ten years earlier may have gained some resistance to the new virus.
• 2003 SARS Outbreak – Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). SARS was first reported in Asia 977
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in February 2003. Over the next few months, the illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained. According to the WHO, a total of 8,098 people worldwide became sick with SARS during the 2003 outbreak. Of these, 774 died. In the United States, only eight people had laboratory evidence of SARS-CoV infection. All of these people had traveled to other parts of the world where SARS was spreading. SARS did not spread more widely in the community in the United States. The main way that SARS seems to spread is by close person-to-person contact. • 2009-2010 H1N1 Swine Flu – This influenza pandemic emerged from Mexico in early 2009 and was declared a public health emergency in the U.S. on April 26, 2009. By June, approximately 18,000 cases had been reported in the U.S. and the virus had spread to 74 countries. Most cases were fairly mild, with symptoms similar to the seasonal flu, but there were cases of severe disease requiring hospitalization and a number of deaths. The CDC estimates that 43-89 million people were infected worldwide, with an estimated 8,870 to 18,300 H1N1-related deaths, including 12,469 deaths in the United States.
• 2020-Ongoing COVID-19 – The COVID-19 or novel coronavirus outbreak began in December 2019 and was declared a pandemic in March of 2020. As of October 12, 2021, over 219 million cases and more than 4.5 million deaths have been reported globally, according to the WHO. Within the U.S. as of October 12, 2021, around 44.5 million cases and around 716,662 deaths have been reported.

Oakdale City CouncilJune 15, 2026

Oakdale City Council
June 15, 2026