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City of Napa
2021 Local Hazard Mitigation Plan Update
Executive Summary.............................................................................................................................xi What is a hazard mitigation plan? ................................................................................................................................................xiii Why have a hazard mitigation plan? ...........................................................................................................................................xiii Why is the plan updated so often?................................................................................................................................................ xiv Stakeholders in HMP Development ............................................................................................................................................. xiv Plan Development and Update Methods.................................................................................................................................... xiv Risk Assessment....................................................................................................................................................................................xv Hazard Exposure and Damage Estimation ............................................................................................................................... xvi Population and Asset Exposure............................................................................................................................................... xvi Damage Assessments.................................................................................................................................................................xvii Summary of Vulnerable Assets: People, Property Value, and Infrastructure............................................................xviii Mitigation Goals ..................................................................................................................................................................................xxii Mitigation Strategy.............................................................................................................................................................................xxii Mitigation Actions..............................................................................................................................................................................xxii Mitigation Action Implementation.............................................................................................................................................xxvi Adoption Records (To be included)............................................................................................ xxvii Section 1. Introduction....................................................................................................................... 1-3
1.1 Purpose................................................................................................................................................................................................1-3
1.2 Background and Scope.................................................................................................................................................................1-3
1.3 Why Update This Plan? ................................................................................................................................................................1-4
1.3.1 Purposes for Planning .........................................................................................................................................................1-5
1.4 Who Will Benefit from This Plan?............................................................................................................................................ 1-5
1.5 How to Use This Plan .................................................................................................................................................................... 1-5 Section 2. What’s New ....................................................................................................................... 2-1
2.1 Mitigation Actions..........................................................................................................................................................................2-1
2.2 New Analysis and Risk Assessment Methodology......................................................................................................... 2-3
2.3 Successful Mitigation Activities Since 2015 ...................................................................................................................... 2-4 Section 3. Planning Process............................................................................................................. 3-1 1-26-2022 Submittal EXHIBIT APage 3 of 416
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STEP 1: Organize Resources .............................................................................................................................................................3-3 Building the Planning Team......................................................................................................................................................3-3 Steering Committee ......................................................................................................................................................................3-3 Planning Committee.....................................................................................................................................................................3-4 Consultant Team............................................................................................................................................................................3-5 Planning Committee Meetings ................................................................................................................................................3-6 Review and Incorporation of Existing Documents ..........................................................................................................3-7 Public Involvement and Outreach ..........................................................................................................................................3-7 STEP 2: Assess the Risk .....................................................................................................................................................................3-9 Identify and Profile Hazards......................................................................................................................................................3-9 Assess Vulnerabilities..................................................................................................................................................................3-9 Web-Based Risk Assessment Mapping and Analysis.....................................................................................................3-9 STEP 3: Develop a Mitigation Strategy........................................................................................................................................3-11 Identify Goals..................................................................................................................................................................................3-11 Develop Capabilities Assessment.........................................................................................................................................3-12 Identify Hazard Problem Statements ..................................................................................................................................3-12 Identify Mitigation Actions......................................................................................................................................................3-13 Mitigation Action Support Tool (MAST)..............................................................................................................................3-13 City Planning Processes Library............................................................................................................................................3-13 Draft HMP........................................................................................................................................................................................3-14 STEP 4: Adopt and Implement the Plan ....................................................................................................................................3-14 Plan Review and Revision........................................................................................................................................................3-14 Plan Adoption and Submittal..................................................................................................................................................3-14 Implement, Evaluate, and Revise the Plan ........................................................................................................................ 3-15 Plan Maintenance........................................................................................................................................................................ 3-15 Section 4. Risk Assessment.............................................................................................................4-1
4.1 Hazard Identification and Screening..................................................................................................................................... 4-1
4.1.1 Hazard Screening .................................................................................................................................................................4-2
4.1.2 Past Major Hazard Events.................................................................................................................................................4-4
4.1.3 Compounding Hazard Events .........................................................................................................................................4-6
4.2 Hazard Prioritization....................................................................................................................................................................4-7
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4.3.1 Geography...............................................................................................................................................................................4-9
4.3.2 Climate................................................................................................................................................................................... 4-12
4.3.3 Demographics and Vulnerable Populations........................................................................................................... 4-12
4.3.4 Economy...............................................................................................................................................................................4-23
4.3.5 Past and Future Trends in Development.................................................................................................................4-24
4.4 Vulnerability Assessment Methods....................................................................................................................................4-27
4.4.1 Population and Asset Inventory ..................................................................................................................................4-27
4.4.2 Hazard Exposure and Damage Estimation............................................................................................................. 4-31
4.5 Vulnerability to Specific Hazards.........................................................................................................................................4-33
4.5.1 Dam Failure Hazard Profile............................................................................................................................................4-35
4.5.2 Drought Hazard Profile ...................................................................................................................................................4-55
4.5.3 Climate Change Hazard Profile ...................................................................................................................................4-67
4.5.4 Earthquake Hazard Profile ............................................................................................................................................4-89
4.5.5 Pandemic Disease Hazard Profile .............................................................................................................................4-117
4.5.6 Flood Hazard Profile.......................................................................................................................................................4-127
4.5.7 Extreme Weather Hazard Profile ..............................................................................................................................4-163
4.5.8 Wildfire Hazard Profile..................................................................................................................................................4-175 Section 5. Mitigation Strategy......................................................................................................... 5-1
5.1 Mitigation Alternatives ................................................................................................................................................................5-1
5.2 Identifying the Problem.............................................................................................................................................................. 5-8
5.3 Capabilities and Adaptive Capacity Assessment ............................................................................................................ 5-8
5.3.1 Planning and Regulatory Mitigation Capabilities .................................................................................................. 5-9
5.3.2 Financial Capabilities....................................................................................................................................................... 5-11
5.3.3 Education and Outreach..................................................................................................................................................5-12
5.3.4 Administrative and Technical Capabilities.............................................................................................................5-13
5.3.5 Capability and Adaptive Capacity Opportunities..................................................................................................5-14
5.3.6 Federal and State Funding Opportunities................................................................................................................5-14
5.4 Mitigation Goals ...........................................................................................................................................................................5-18
5.5 Mitigation Actions .......................................................................................................................................................................5-19
5.5.1 Prioritization of Mitigation Actions............................................................................................................................5-20
5.5.2 Mitigation Action Plan ....................................................................................................................................................5-22 Section 6. Plan Implementation and Maintenance ................................................................... 6-1 1-26-2022 Submittal EXHIBIT APage 5 of 416
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6.1 Plan Adoption.................................................................................................................................................................................. 6-1
6.2 Plan Implementation ................................................................................................................................................................... 6-1
6.2.1 Steering Committee ............................................................................................................................................................ 6-1
6.3 Monitoring, Evaluating and Updating the HMP................................................................................................................6-2
6.3.1 Schedule...................................................................................................................................................................................6-2
6.3.2 Mitigation Action Support Tool (MAST) Updates ...................................................................................................6-2
6.3.3 Process .....................................................................................................................................................................................6-3
6.3.4 Continuing Public Involvement.....................................................................................................................................6-3
6.3.5 HMA Monitoring...................................................................................................................................................................6-4
6.3.6 Incorporation into Other Planning Mechanisms ...................................................................................................6-6
6.1.1 Planning Integration Processes .............................................................................................................................6-7 Section 7. Works Cited....................................................................................................................... 7-1
Appendix A. Analysis Methodology.............................................................................................. A-1 A.1. Natural Hazard Exposure .........................................................................................................................................................A-2 Damage Estimation with Hazus...................................................................................................................................A-2 Distinguishing Results – Natural Hazard Exposure Analysis vs Hazus Results.....................................A-4 A.2. Analysis Data................................................................................................................................................................................A-4 Assets, Value, and Population ......................................................................................................................................A-4 Natural Hazard Data.........................................................................................................................................................A-5 Methodology Overview.................................................................................................................................................A-10 Data Dictionary .................................................................................................................................................................A-11 Insured Assets Roll.........................................................................................................................................................A-14 Appendix B. Process Documentation ............................................................................................B-1 List of Figures
Figure ES 1: Risk Assessment Methodology Summary .......................................................................................................xvi Figure ES 2: Exposure explanation graphic.............................................................................................................................xvii Figure ES 3: Hazus Damage Estimation Example............................................................................................................... xviii Figure ES 4: Landslide and Wildfire Risk Exposure Snapshot..........................................................................................xix Figure ES 5: Dam Inundation and Sea Level Rise Snapshots............................................................................................. xx Figure ES 6: West Napa Earthquake (M6.7) Scenario and Flood Risk Exposure Snapshots .................................xxi Figure 1-1: Location of the City of Napa ....................................................................................................................................... 1-4 1-26-2022 Submittal EXHIBIT APage 6 of 416
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Figure 2-1: Oxbow Commons and Flood Bypass Project...................................................................................................... 2-5 Figure 3-1: City of Napa HMP Planning Process...................................................................................................................... 3-2 Figure 3-2: City HMP Planning Team........................................................................................................................................... 3-3 Figure 3-3: Snapshot of community survey results............................................................................................................... 3-8 Figure 3-4: RAMP Access at mitigatehazards.com...............................................................................................................3-10 Figure 3-5: RAMP showing the population of Napa exposed within the FEMA 100-YR Flood Hazard layer. 3-11 Figure 3-6: Categories of issues addressed in problem statements...............................................................................3-12 Figure 3-7: MAST elements and Cal OES Grant Applications...........................................................................................3-16 Figure 4-1: Prioritized Hazard Assessment Matrix for the City of Napa........................................................................4-8 Figure 4-2: City of Napa Geographic Overview...................................................................................................................... 4-10 Figure 4-3: Napa Water Division Overview...............................................................................................................................4-11 Figure 4-4: Owners and Renters .................................................................................................................................................. 4-13 Figure 4-5: City of Napa Median Household Income Distribution ..................................................................................4-15 Figure 4-6: City of Napa Population Under Age 18................................................................................................................ 4-19 Figure 4-7: City of Napa Population Over Age 65 .................................................................................................................. 4-19 Figure 4-8: Household Language ................................................................................................................................................. 4-21 Figure 4-9: City of Napa Race Distribution 2012-2017.......................................................................................................... 4-21 Figure 4-10: Data Source and Method........................................................................................................................................4-27 Figure 4-11: City of Napa Critical Facilities.............................................................................................................................. 4-31 Figure 4-12: Hazard Exposure Explanation Graphic............................................................................................................ 4-31 Figure 4-13: Hazus Damage Estimation Example.................................................................................................................4-32 Figure 4-14: Oroville Dam Spillway after 2017 Failure ........................................................................................................4-38 Figure 4-15: Dam Inundation Exposure.....................................................................................................................................4-40 Figure 4-16: Dam Failure Vulnerability Snapshot Map.......................................................................................................4-44 Figure 4-17: Population Exposure to Dam Inundation by Zone.......................................................................................4-45 Figure 4-18: Improved Parcel and Government Property Loss Estimations (Conn Creek Dam) .......................4-50 Figure 4-19: Improved Parcel and Government Property Loss Estimations (Milliken Dam) ..............................4-50 Figure 4-20: Improved Parcel and Government Property Loss Estimations (Rector Creek Dam) ....................4-52 Figure 4-21: Drought-Lowered Irrigation Reservoir in Napa Valley in 2014...............................................................4-58 Figure 4-22: San Pablo Bay Drought Severity Timeline 2000-2021................................................................................ 4-61 Figure 4-23: City of Napa Sea-Level Rise Potential (RCP 4.5)...........................................................................................4-70 Figure 4-24: City of Napa Comparison of Observed and Projected Annual Max Temps ......................................4-78 Figure 4-25: City of Napa Sea-Level Rise Vulnerability and Exposure Snapshot....................................................4-80 Figure 4-26: Earthquake Faulting................................................................................................................................................4-89 Figure 4-27: City of Napa - Potential for Liquefaction.........................................................................................................4-90 Figure 4-28: Zones of Required Investigation.........................................................................................................................4-96 Figure 4-29: Fault Probability Map for Napa County ...........................................................................................................4-97 Figure 4-30: City of Napa Earthquake Shaking Potential ..................................................................................................4-99 Figure 4-31: M 6.7 West Napa Scenario Earthquake Severity..........................................................................................4-101 Figure 4-32: West Napa Exposure and Snapshot Map......................................................................................................4-103 Figure 4-33: Population Exposure to M6.7 West Napa Scenario ...................................................................................4-104 Figure 4-34: FEMA Flood Risk Exposure ................................................................................................................................4-134 1-26-2022 Submittal EXHIBIT APage 7 of 416
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Figure 4-35: City of Napa Best Available Mapping (DWR) Flooding.............................................................................4-136 Figure 4-36: City of Napa Repetitive Loss Areas..................................................................................................................4-138 Figure 4-37: Stonecrest RL Area .................................................................................................................................................4-141 Figure 4-38: RiverPointe RL Area.............................................................................................................................................. 4-142 Figure 4-39: Soscol North RL Area............................................................................................................................................ 4-143 Figure 4-40: Oxbow West RL Area ............................................................................................................................................ 4-144 Figure 4-41: Oxbow East RL Area ...............................................................................................................................................4-145 Figure 4-42: Soscol South RL Area ........................................................................................................................................... 4-146 Figure 4-43: FEMA Flood Risk Exposure and Snapshot Map ......................................................................................... 4-151 Figure 4-44: Flood Population Exposure Summary ...........................................................................................................4-152 Figure 4-45: 100-YR Flood Damage Estimation by Occupancy......................................................................................4-158 Figure 4-46: 500 YR Flood Damage Estimation by Occupancy Type ......................................................................... 4-160 Figure 4-47: City of Napa - Average Annual Precipitation ..............................................................................................4-166 Figure 4-48: City of Napa - 30-Year Normal Maximum Temperature for July........................................................4-167 Figure 4-49: City of Napa - Annual Average Wind Speed (Power Class)....................................................................4-168 Figure 4-50: Wildfire Conflagration...........................................................................................................................................4-181 Figure 4-51: Historic Fire Perimeters Near the City of Napa...........................................................................................4-182 Figure 4-52: Data Sources for Composite Wildfire Severity in the City of Napa.....................................................4-187 Figure 4-53: City of Napa Wildfire Risk Exposure ...............................................................................................................4-188 Figure 4-54: City of Napa Mean Wildfire Return Intervals.............................................................................................. 4-184 Figure 4-55: City of Napa Exposure Wildfire Vulnerability and Snapshot Map......................................................4-191 Figure 4-56: Population Exposed to Wildfire Risk...............................................................................................................4-192 Figure 5-1: Mitigation Action Key.................................................................................................................................................5-22 Figure 5-2: Diagram of MAST viewing details ........................................................................................................................5-23 Figure 6-1: MAST and Cal OES Grant Applications .................................................................................................................6-5 Figure 6-2: HMGP Timeline ..............................................................................................................................................................6-6 Figure A-1: Hazard Exposure...........................................................................................................................................................A-2 Figure A-2: Flood Depth and Damage Curves ..........................................................................................................................A-3 Figure A-3: Hazus Damage Estimations ....................................................................................................................................A-3 Figure A-4: Data Analysis Methodology...................................................................................................................................A-10 List of Tables
Table 2-1: Cancelled Previous Mitigation Actions....................................................................................................................2-1 Table 3-1: HMP Steering Committee .............................................................................................................................................3-3 Table 3-2: HMP Planning Committee ...........................................................................................................................................3-4 Table 3-3: HMP Update Consultant Team...................................................................................................................................3-6 Table 3-4: Meeting Summary...........................................................................................................................................................3-6 Table 4-1: Document Review Crosswalk .....................................................................................................................................4-2 Table 4-2: Hazard prioritization......................................................................................................................................................4-3 Table 4-3: Disaster Declarations in Napa County 2000- present.......................................................................................4-5 1-26-2022 Submittal EXHIBIT APage 8 of 416
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Table 4-4: Household Income and Poverty Levels ............................................................................................................... 4-14 Table 4-5: Senior Households........................................................................................................................................................ 4-16 Table 4-6: Households with Minors <18..................................................................................................................................... 4-17 Table 4-7: Disability Status of Non-Institutionalized Population in the City of Napa in 2013-2017 .................4-23 Table 4-8: Top Sectors in City of Napa, 2017............................................................................................................................4-24 Table 4-9: City of Napa Parcel Counts and Value..................................................................................................................4-29 Table 4-10: FEMA Hazard Potential Classification...............................................................................................................4-39 Table 4-11: Dams with Potential Impacts to the City of Napa...........................................................................................4-39 Table 4-12: Population Exposure to Dam Failure...................................................................................................................4-45 Table 4-13: Parcel Values at Risk from Dam Inundation....................................................................................................4-46 Table 4-14: Critical Infrastructure Points in Dam Inundation Zones ............................................................................4-47 Table 4-15: Miles of Critical Infrastructure (Linear) in Dam Inundation Zones ........................................................4-48 Table 4-16: Improved Parcel and Government Property Loss Estimations (Conn Creek Dam) .........................4-49 Table 4-17: Improved Parcel and Government Property Loss Estimations (Milliken Dam) ................................4-50 Table 4-18: Improved Parcel and Government Property Loss Estimations (Rector Creek Dam)........................4-51 Table 4-19: Damage Estimate Insurance Roll Details (Conn Creek Dam)....................................................................4-52 Table 4-20: Dam Failure Problem Statements........................................................................................................................4-53 Table 4-21: Drought Classifications and Impacts for California......................................................................................4-60 Table 4-22: Drought Problem Statements ................................................................................................................................4-65 Table 4-23: Climate Change-Related Hazards and Cross-References in HMP .........................................................4-67 Table 4-24: Probability of Exceeding Global Mean Sea-Level Rise (Median Value) Scenarios in 2100...........4-69 Table 4-25: Annual Average Maximum Temperatures under RCP4.5..........................................................................4-76 Table 4-26: Annual Average Maximum Temperature under RCP8.5............................................................................4-77 Table 4-27: Population Exposure to Sea-Level Rise .............................................................................................................4-82 Table 4-28: Population Exposure to Sea-Level Rise by Degree........................................................................................4-82 Table 4-29: Parcels Exposed to Sea Level Rise.......................................................................................................................4-83 Table 4-30: Critical Infrastructure Points in Sea-Level Rise Regions...........................................................................4-84 Table 4-31: Miles of Critical Infrastructure (Linear) in Sea-level Rise Regions.........................................................4-84 Table 4-32: Climate Change Problem Statements ................................................................................................................4-86 Table 4-33: Earthquake Magnitude Classes (Mw)................................................................................................................. 4-91 Table 4-34: Modified Mercalli Intensity Level Descriptions.............................................................................................4-92 Table 4-35: Modified Mercalli Scale and Peak Ground Acceleration............................................................................4-93 Table 4-36: Earthquakes in or near City of Napa M4.5 or Greater Since 2000...........................................................4-94 Table 4-37: Population Exposure to M6.7 West Napa Scenario .....................................................................................4-104 Table 4-38: Seismic Benchmark Years....................................................................................................................................4-105 Table 4-39: Definitions of FEMA Building Types ................................................................................................................4-106 Table 4-40: Parcel Exposure to M6.7 West Napa .................................................................................................................4-107 Table 4-41: Critical Facility Exposure to West Napa Scenario .......................................................................................4-108 Table 4-42: Lifeline Exposure West Napa Scenario............................................................................................................4-109 Table 4-43: Hazus Building Damage Descriptions...............................................................................................................4-113 Table 4-44: Damage Estimations for M6.7 West Napa Scenario....................................................................................4-114 Table 4-45: Damage Estimations for M6.7 West Napa Scenario ....................................................................................4-115 1-26-2022 Submittal EXHIBIT APage 9 of 416
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Table 4-46: Earthquake Problem Statements........................................................................................................................4-116 Table 4-47: Napa County Vaccine Preventable Disease Cases 2001-2018 .................................................................4-121 Table 4-48: Parameter Values Contingent on Five COVID-19 Pandemic Planning Scenarios .........................4-123 Table 4-49: Pandemic Disease Problem Statements .........................................................................................................4-125 Table 4-50: Flood Insurance Statistics for the City of Napa ............................................................................................4-131 Table 4-51: City of Napa Flood Events Since 2000...............................................................................................................4-132 Table 4-52: Summary of Relevant Discharges in Napa County.................................................................................... 4-148 Table 4-53: Summary Population Exposure to Flood in the City of Napa..................................................................4-152 Table 4-54: Parcels Exposed to NFIP Flood Zones in the City of Napa .......................................................................4-153 Table 4-55: Critical Facility Points in the Floodplain.........................................................................................................4-154 Table 4-56: Lifelines in the Floodplain in the City of Napa .............................................................................................4-155 Table 4-57: 100 YR Flood Damage Estimation by Occupancy Type .............................................................................4-157 Table 4-58: 100 YR Flood Damage Estimation of City Facilities....................................................................................4-158 Table 4-59: Damage Estimation Summary for 500 yr. Floodplain................................................................................4-159 Table 4-60: Flood Problem Statements....................................................................................................................................4-161 Table 4-61: Classes of Wind Power Density at 10 m and 50 ma......................................................................................4-169 Table 4-62: Extreme weather Problem Statements........................................................................................................... 4-174 Table 4-63: Wildfire Events Near the City of Napa 2000-2020....................................................................................... 4-180 Table 4-64: Populations Exposed to Wildfire Risk ..............................................................................................................4-192 Table 4-65: Residential Buildings and Content within Fire Hazard Severity Zones.............................................4-193 Table 4-66: Critical Facility Exposure to Fire Hazard Severity Zones........................................................................ 4-194 Table 4-67: Lifelines in Fire Hazard Severity Zones...........................................................................................................4-195 Table 4-68: Wildfire Problem Statements...............................................................................................................................4-196 Table 5-1: City of Napa Planning and Regulatory Mitigation Capabilities.....................................................................5-9 Table 5-2: City of Napa Fiscal Capabilities Summary...........................................................................................................5-11 Table 5-3: City of Napa Education/ Outreach Capabilities Summary ........................................................................... 5-12 Table 5-4: City of Napa Administrative and Technical Capabilities.............................................................................. 5-13 Table 5-5: Federal and State Funding Opportunities ........................................................................................................... 5-15 Table 5-6: Mitigation Action Tracker..........................................................................................................................................5-25 Table A-1: Data Dictionary...............................................................................................................................................................A-11 Table A-2: Insured Asset Roll........................................................................................................................................................A-14 1-26-2022 Submittal EXHIBIT APage 10 of 416
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Executive Summary
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The City of Napa (“City”) prepared this hazard mitigation plan to guide city officials in protecting people and property within the city from the effects of natural disasters and hazard events. This plan demonstrates the City of Napa’s commitment to reducing risk from natural hazards through mitigation and serves as a tool to direct city resources to achieve optimum results with available administrative, technical, and financial resources.
The term “hazard mitigation” refers to actions or strategies that can reduce or eliminate long-term risks caused by natural disasters. Mitigation activities can be developed, planned, and implemented before or after a disaster occurs. After disasters, repairs and reconstruction often are completed in such a way as to simply restore damaged property to pre-disaster conditions. These efforts may return property and infrastructure to “the norm”, but the replication of predisaster conditions may result in a repetitive cycle of damage and reconstruction. Hazard mitigation planning in the City of Napa can break this repetitive cycle by reducing vulnerability to hazards through smart construction and proper planning of future development and critical infrastructure. Hazard mitigation activities can be conducted through a wide variety of mitigation strategies, such as construction of regional flood control projects or implementing fuel reduction around buildings within high wildfire risk areas.
What is a hazard mitigation plan?
This hazard mitigation plan provides an explanation of potential hazards within the city. It also describes how hazards may impact the city based on various factors such as hazard type and geographic distribution of risk in relation to people and property within the city. This plan identifies risks to vulnerable assets, both people and property. Most importantly, the mitigation strategy presented in this plan responds to the identified vulnerabilities within the community and provides prescriptions or actions to achieve the greatest risk reduction based upon available resources. The City intends to save lives, reduce injuries, reduce property damage, and protect natural resources for future generations through mitigation activities.
Why have a hazard mitigation plan?
A hazard mitigation plan can reduce property damage, injuries, and even deaths when hazard events strike. Mitigating hazards can also help reduce impacts from loss of critical services and lifelines within communities. The purpose of this Hazard Mitigation Plan (HMP) is twofold. First, it provides resources for the city and residents wishing to conduct hazard mitigation efforts by identifying areas of extreme risk and providing financial and technical mitigation resources based upon current gaps.
Second, it provides the city continued access to grant funding from FEMA to conduct hazard mitigation activities. The passage of the Disaster Mitigation Act in 2000 (DMA 2000) requires proactive hazard 1-26-2022 Submittal EXHIBIT APage 13 of 416
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mitigation planning as a condition of receiving certain federal financial assistance under the Robert T.
Stafford Act. DMA 2000 encourages state and local authorities to work together on pre-disaster planning to assist local governments to accurately assess mitigation needs, resulting in faster allocation of funding and more cost-effective risk reduction projects under
FEMA’s Hazard Mitigation Assistance program.
Why is the plan updated so often?
As a DMA 2000 requirement, the plan must be updated
every five years to remain in compliance with federal mitigation grant conditions. Federal regulations require hazard mitigation plans to include a plan for monitoring, evaluating, and updating the hazard mitigation plan. An update process provides an opportunity to reevaluate recommendations, monitor the impacts of actions that have been accomplished, and determine if there is a need to change the focus of mitigation strategies over time. Grant compliance is contingent on meeting the plan update requirements in the Code of Federal Regulations (CFRs). Jurisdictions that allow a plan to expire are not able to pursue funding under the Robert T. Stafford Act.
Stakeholders in HMP Development
A planning committee was formed to develop and steer content in this plan, including the goals, objectives, mitigation strategies, and implementation methods to reduce risk. Stakeholders included city representatives, local agencies, local businesses, local citizens, and non-governmental organizations.
The public also participated in development of this HMP through an online survey to residents and through public review of the draft HMP. Community feedback played a key role in prioritizing future mitigation actions, goals, and implementation steps.
Plan Development and
Update Methods
Hazard mitigation planning is the
process through which hazards are identified, likely
impacts determined, mitigation goals set, and appropriate mitigation strategies identified. This plan documents the hazard mitigation planning process that the City of Napa used to increase natural hazard resiliency in the community. The City followed the recommended FEMA four-step process to 1-26-2022 Submittal EXHIBIT APage 14 of 416
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develop this 2021 plan update. Updates include a new risk assessment, revaluation of goals and objectives, development of new mitigation actions, enhancements for implementing mitigation actions, updates to all sections of the 2015 plan, and a new website for stakeholder involvement and public information.
Risk Assessment
The risk assessment measures the potential loss of life, personal injury, economic injury, and property or infrastructure damage resulting from natural hazards in order to determine vulnerability. For this update, the risk assessment utilized new data and technologies available since 2015. The City used risk assessment information to rank risks and to gauge the potential impacts of each hazard of concern in the Operational Area. The risk assessment included:
▪ Hazard identification and profiling,
▪ Assessment of the impact of hazards on physical, social, and economic assets, ▪ Identification of particular areas of vulnerability,
▪ Additional impacts of each hazard due to climate change, and ▪ Estimates of the cost of potential damage.
The following natural hazard threats were identified and profiled as priority hazards:
Dam Failure
SECTION 4.5.1
Earthquake
SECTION 4.5.4
Extreme Weather
SECTION 4.5.7
Drought
SECTION 4.5.2
Pandemic Disease
SECTION 4.5.5
Wildfire
SECTION 4.5.8
Climate Change
SECTION 4.5.3
Flood
SECTION 4.5.6
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Hazard Exposure and Damage Estimation
In the City of Napa, earthquakes, flooding, slope failure, dam failure, and wildfire have known geographic extents and corresponding spatial information, which make exposure and damage estimation possible. In order to describe vulnerability for each hazard, it is important to understand the total population and total assets at risk. This provides the estimated damage and losses expected during a “worst case scenario” event for each hazard.
Figure ES 1: Risk Assessment Methodology Summary
Population and Asset Exposure
The total counts of parcels, people, facilities, assets, and the sum of values within the planning area which could be exposed to a hazard event is referred to as exposure in this plan. A natural hazards overlay was developed to reflect the combination of many known natural hazard spatial footprints. The spatial overlay method enables summarization of building values, parcel counts, population exposure, and critical facility exposure within a hazard’s geographic extents. Figure ES 2 illustrates parcels both exposed and not exposed to a sample flood zone. This method has been used to evaluate exposure for earthquakes, landslides, flooding, dam inundation, and wildfire. For a more detailed explanation on Risk Assessment Methods, see Section 4.3 and Appendix A.
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Figure ES 2: Exposure explanation graphic
Damage Assessments
The risk assessment also includes a detailed loss estimation for flood and earthquake utilizing FEMA’s Hazus software. Hazus is a nationally-applicable, standardized methodology that contains models for estimating potential losses from earthquakes, floods, and hurricanes. Hazus uses Geographic Information Systems (GIS) technology to estimate physical, economic, and social impacts of disasters. For this planning effort, Hazus was used to generate damage estimations due to possible earthquakes and flooding.
The estimated damage and losses provided by the Hazus Software is a “worst case scenario” event and provides the ability to understand possible widescale damage to buildings and facilities.
In the hypothetical map in Figure ES 3, even though both structures are exposed to flooding, it is predicted that the structure with a first floor height below the depth of flooding will receive significantly more damage than the structure with a first floor height above the expected water depth. For a more detailed explanation on risk assessment methods, see Section 4.3 and Appendix A. 1-26-2022 Submittal EXHIBIT APage 17 of 416
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Figure ES 3: Hazus Damage Estimation Example
Summary of Vulnerable Assets: People, Property Value, and Infrastructure Hazards with spatial boundaries can be analyzed to demonstrate the amount of population, critical infrastructure, and parcels within each hazard’s footprint. At-risk populations, critical infrastructure, improved parcels, and loss results for each hazard category are provided in bar chart summary tables throughout this plan to evaluate the percentage of assets exposed to different types of hazards. The sideby-side comparison allows officials to evaluate the impacts of potential hazards to determine what hazards to direct energy and financial resources for mitigation activities. For detailed vulnerabilities assessment information, see the individual hazard specific sections presented in Section 4.5. This Executive Summary provides map summaries for the profiled hazards in Figure ES 5 through Figure ES
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Figure ES 4: Landslide and Wildfire Risk Exposure Snapshot 1-26-2022 Submittal EXHIBIT APage 19 of 416
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Figure ES 5: Dam Inundation and Sea Level Rise Snapshots 1-26-2022 Submittal EXHIBIT APage 20 of 416
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Figure ES 6: West Napa Earthquake (M6.7) Scenario and Flood Risk Exposure Snapshots 1-26-2022 Submittal EXHIBIT APage 21 of 416
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Mitigation Goals
The Steering Committee reviewed and confirmed, with minor updates, the goals from the 2015 City of Napa Hazard Mitigation Plan:
Goal 1: Promote a flood safe community.
Goal 2: Promote an earthquake safe community.
Goal 3: Promote a fire safe community.
Goal 4: Promote an overall natural hazard-safe community.
Goal 5: Create a more disaster resilient community.
Mitigation Strategy
The mitigation strategies and activities designed to reduce or eliminate losses resulting from natural hazards are the centerpiece of the mitigation planning process. Through the mitigation actions, the city will become more resilient to disasters. Actions identified in this plan may or may not be geared toward grant funding under HMA. Rather, the focus was the initiatives’ effectiveness in achieving the goals of the plan within the City of Napa’s capabilities.
The City of Napa selected a range of appropriate mitigation actions to work toward achieving the HMP’s goals. These initiatives also are summarized in the following tables.
Mitigation Actions
Mitigation No. Hazard Type Year Title/Description Priority ma-AH-CN-0 All Hazard 2015 Improve existing communication systems, especially developing redundant communication systems and wireless infrastructure.
High
ma-AH-CN-1 All Hazard 2015 Build an alternate EOC High
ma-AH-CN-2 All Hazard 2015 Create a Remote Workers Infrastructure Medium ma-AH-CN-3 All Hazard 2015 Promote greater public awareness of disaster preparedness, hazard mitigation, and disaster recovery.
High
ma-AH-CN-4 All Hazard 2015 Maintain and equip an Emergency Operation Center (EOC) for immediate availability in the event of a disaster.
High
ma-AH-CN-5 All Hazard 2015 Work with local businesses to prepare Emergency Preparedness Plans by working with other agencies and
advocacy organizations to distribute to and assist businesses with the preparation of plans in the case of disaster.
High
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Mitigation No. Hazard Type Year Title/Description Priority ma-AH-CN-7 All Hazard 2015 Develop short-term shelter options for residents and animals by working with the American Red Cross, Humane Society, animal shelters, pet stores, local veterinarians and others.
Identify locations, necessary facilities, responders, etc.
High
ma-AH-CN-8 All Hazard 2015 Develop procedures for inspecting and tagging business for occupancy after a disaster (Post Disaster Restoration
Ordinance)
Medium
ma-AH-CN-9 All Hazard 2015 Establish the position of Disaster Coordinator for the City of Napa
Medium
ma-AH-CN-13 All Hazard 2015 Develop a program to identify evacuation routes and procedures for all sensitive facilities and implement programs to practice evacuation and safety maneuvers.
Low
ma-AH-CN-57 All Hazard 2021 Construct backup generators at critical facilities (fire stations, hospital) and sheltering locations to respond to hazard events in loss of power.
High
ma-CC-CN-14 Climate
Change
2015 Develop a Climate Action Plan applicable with state and federal law
Low
ma-CC-CN-51 Climate
Change
2021 Conduct public outreach regarding cooling center availability, especially targeting vulnerable populations; periodically review available cooling center usage, distribution and availability throughout the City.
Medium
ma-DF-CN-15 Dam Failure 2015 Maintain a program on dam safety and continue to cooperate with the State Division of Dam Safety in addressing any needed dam maintenance or structural improvements.
High
ma-DF-CN-52 Dam Failure 2021 Develop a dam failure emergency operations plan (EOP) at the City level or in coordination with Napa County
High
ma-DR-CN-16 Drought 2015 Secure internal and external water supply sources and maintain reservoir levels to withstand drought years.
High
ma-DR-CN-54 Drought 2021 Develop a public education campaign to encourage water conservation during drought, in collaboration with the Napa Valley Drought Contingency Plan Task Force and Napa
Sanitation District. The intent is to avoid or delay issuance of water restriction emergency declarations.
Medium
ma-DR-CN-55 Drought 2021 Implement recommendations from the Napa Valley Drought Contingency Plan. Incorporate into the City's Urban Water Management Plan.
High
ma-EQ-CN-17 Earthquake 2015 Develop a program to educate the community on the various methods of retrofitting pre-earthquake code designed
structures, which would include: workshops, literature and public safety announcements.
High
ma-EQ-CN-18 Earthquake 2015 Encourage the study and rehabilitation of high occupancy structures (such as multi-family residences and large public assembly facilities) susceptible to collapse or failure in an earthquake.
High
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Mitigation No. Hazard Type Year Title/Description Priority ma-EQ-CN-20 Earthquake 2015 Install earthquake resistant transmission and distribution pipeline joints, automation control features, and water pipeline rehabilitation or replacement across known faults to protect against catastrophic failures
Medium
ma-EQ-CN-56 Earthquake 2021 Encourage privately owned unreinforced masonry buildings and critical facilities (e.g. churches, hotels, other gathering facilities) to evaluate the ability of the buildings to withstand earthquakes and to address any deficiencies identified; explore a cost-share program to assist private owners in conducting seismic retrofits.
High
ma-EW-CN-58 Extreme
Weather
2021 Develop cost share program to help private landowners with tree maintenance to avoid power outages and damage during windstorms.
Medium
ma-EW-CN-59 Extreme
Weather
2021 Replace dying or dead evergreen vegetation with wind resistant vegetation and implement annual tree trimming program.
Medium
ma-FL-CN-23 Flood 2015 Complete approved Napa River Flood Protection Project by continuing to assist the U.S. Army Corps of Engineers, Napa County Flood Control and Water Conservation District, other responsible agencies, and the public to maintain funding for the development of the Flood Project.
Extreme
ma-FL-CN-24 Flood 2015 Pursue funding for the design and construction of storm drainage projects to protect properties that will not be fully protected by the Flood Protection Project, including home elevations, property acquisitions, upstream storage such as detention basins, and channel widening with the associated right-of-way acquisitions, relocations and environmental mitigations.
High
ma-FL-CN-25 Flood 2015 Improve Countywide flood surveillance/early warning system High ma-FL-CN-26 Flood 2015 Complete Soscol Interior Drainage Project Preliminary Design High ma-FL-CN-27 Flood 2015 Continue to apply floodplain management regulations for development in the flood plain and floodway.
High
ma-FL-CN-28 Flood 2015 Increase coverage of Storm Watch sensors to include small streams that, due to land use changes, have demonstrated an impact on existing streams and urban flooding.
Medium
ma-FL-CN-29 Flood 2015 Distribute NOAA weather Radios to high risk, limited income families living in flood zones. Develop program of at cost NOAA radios for families in the various flood zones in Napa County.
Provide weather radios to block captains.
Low
ma-FL-CN-30 Flood 2015 Periodically update the Flood Insurance Rate Maps to reflect the improvements that have been completed as part of the Flood Protection Project.
High
ma-FL-CN-49 Flood 2021 Implement various flood control projects after approved Flood Control Project. For example, additional pump stations are needed to increase the functionality and resilience of the flood wall along the west side of the Napa River.
High
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Mitigation No. Hazard Type Year Title/Description Priority ma-FL-CN-62 Flood/ Heavy
Rain
2021 Implement the Trower Avenue Storm Drain Improvements, Phase II project, which consists of improvements to alleviate flooding from heavy rain events along Valencia Street,
Yosemite Street, Diablo Street and Glacier Drive.
High
ma-PN-CN-31 Pandemic 2015 Coordinate efforts with health community to respond to communicable diseases
High
ma-PN-CN-32 Pandemic 2015 Ensure that the city, the hospitals and the County Health Dept. coordinate efforts to educate, prepare for and respond to outbreaks of communicable disease
Medium
ma-PN-CN-60 Pandemic 2021 Assess and institute necessary upgrades to critical facilities to allow for usage during pandemic, including adequate
ventilation and physical barriers
Medium
ma-WF-CN-41 Wildfire 2015 Develop Structural Protection Plans for Wildland Urban Interface Areas
High
ma-WF-CN-42 Wildfire 2015 Continue to support the Napa Communities Firewise Foundation in the development of Fire Safe Councils and implementation of the 2021 Community Wildfire Protection Plan
High
ma-WF-CN-43 Wildfire 2015 Continue to upgrade existing water utility infrastructure to increase redundancy in high fire hazard areas especially at the rural and urban interface to minimize the risk of losing access to infrastructure during an event.
Medium
ma-WF-CN-44 Wildfire 2015 Ensure the Fire Department reviews all building plans in WUI areas for defensible space, emergency vehicle access, fire flow and ignition resistant construction requirements.
Low
ma-WF-CN-45 Wildfire 2015 Provide an ongoing vegetation management program such as the City's Weed Abatement ordinance to prohibit the spread of wildfire in ground and aerial fuels and to assist homeowners in developing defensible space.
Low
ma-WF-CN-46 Wildfire 2021 Coordinate watershed protection efforts within the Lake Hennessey and Lake Milliken watersheds to protect drinking water supplies from water quality impacts.
High
ma-WF-CN-47 Wildfire 2021 Implement Lake Hennessy Intake Pump Station Defensible Space /Construction Upgrade
High
ma-WF-CN-48 Wildfire 2021 Conduct Lake Hennessy Pipeline Protection Project High ma-WF-CN-50 Wildfire 2021 Implement demonstration fuels treatment and emergency access project at Timberhill Park
Extreme
ma-WF-CN-61 Wildfire 2021 Maintain Fire Access Roads and evacuation routes that have been identified throughout the City of Napa.
Extreme
ma-WF-CN-63 Wildfire 2021 Fund and implement the Milliken Raw Water Pipeline Hardening Project
Extreme
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Mitigation Action Implementation
Despite City efforts, no amount of planning or mitigation can prevent disasters from occurring or eliminate the risk and impacts of such events. Hazard events will continue to occur, and the City will take actions to reduce the risks these hazards pose to life, property, and the economy. While this HMP identifies opportunities for reasonable mitigation actions, each individual has a responsibility to be aware of the potential hazards where they live and to minimize their own household’s vulnerability.
The City of Napa’s ability to carry out mitigation is limited to those facilities over which it has authority.
The City does not have direct authority over schools, water and sanitation districts, private gas, electric and communication utilities, state and federal highways and facilities, private hospitals, or neighboring cities and tribes. The City will focus on actions within its authority while seeking to cooperatively work with other entities to address mutual areas of vulnerability and interdependence.
Full implementation of the plan’s recommendations will take time and resources. The measure of the plan’s success will be the coordination and pooling of resources between the city and other local and regional agencies and stakeholders and maintaining these successes over time. Teaming together to seek financial assistance at the state and federal level will be a priority to initiate projects that are dependent on alternative funding sources. This plan was built upon the effective leadership of a multi-disciplined steering committee and a process that relied heavily on public input and support. The plan will succeed for the same reasons.
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Adoption Records (To be included)
To comply with DMA 2000, the City Council officially adopted this City of Napa Hazard Mitigation Plan upon plan approval from Cal OES and FEMA. The adoption of the HMP in its entirety recognizes the City’s commitment to reducing the impacts of natural hazards within the planning area. See the Record of Adoption, below.
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Section 1. Introduction
1.1 Purpose
The City of Napa (“City”) prepared this update to its Hazard Mitigation Plan (HMP), originally approved by the Federal Emergency Management Agency (FEMA) in 2004 and last updated in 2015. The plan in its current form reflects a comprehensive update in 2021. The purpose of this plan is to guide hazard mitigation planning to better protect the people and property of the city from the effects of hazard events.
This plan demonstrates the city’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 ensure the City of Napa’s continued eligibility for certain federal disaster assistance, specifically the FEMA Hazard Mitigation Assistance (HMA) grants, including the Hazard Mitigation Grant Program (HMGP), Building Resilient Infrastructure and Communities (BRIC), and Flood Mitigation Assistance Program (FMA).
The plan also serves as the City’s Floodplain Management Plan, important for maintaining and improving the standing of the city in the National Flood Insurance Program’s Community Rating System (CRS). CRS provides for lower flood insurance premiums to the residents in the city.
1.2 Background and Scope
Each year in the United States, natural 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. These monies only partially reflect the true cost of disasters because additional expenses incurred by insurance companies and nongovernmental organizations are not reimbursed by tax dollars. Many natural disasters are predictable, and much of the damage caused by these events can be reduced 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 demonstrates 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. (National Institute of Building Sciences, 2017) The City of Napa Hazard Mitigation Plan encompasses approximately 18.2 square miles and covers 11,650 acres. This is hereinafter referred to as the “planning area.” Within the boundaries of the city limits, there are several unincorporated islands which remain under Napa County’s jurisdiction, particularly in the Terrace Shurtleff and Pueblo planning area. See Figure 1-1.
A planning committee was formed to develop and steer content in this plan. This committee consists of City of Napa staff and local stakeholders who worked together to create the goals, objectives, mitigation 1-26-2022 Submittal EXHIBIT APage 31 of 416
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strategies, and implementation methods
to reduce natural hazard risk within the
planning area. Any jurisdiction or
organization may participate in the
planning process. However, to obtain
FEMA approval, each local jurisdiction
must meet all requirements of hazard
mitigation planning outlined in 44 C.F.R.
§ 201.6.
1.3 Why Update This Plan?
Hazard mitigation is a way to reduce or
alleviate the loss of life, personal injury,
and property damage that can result from
a disaster through long and short-term
strategies. It involves strategies such as
planning, policy changes, programs,
projects, and other activities that can
mitigate the impacts of hazards. The
responsibility for hazard mitigation lies
with many, including private property
owners, business and industry, and local,
state, and federal governments.
The Federal Disaster Mitigation Act of
2000 (DMA 2000) required state and local
governments to develop hazard mitigation plans as a condition of federal disaster grant assistance. 42 U.S.C. § 5121 et seq.; Pub. L. No. 106-390. Prior to 2000, federal disaster funding focused on disaster relief and recovery, with limited funding for hazard mitigation planning. DMA 2000 increased the emphasis on planning for disasters before they occur.
DMA 2000 encourages state and local authorities to work together on pre-disaster planning and promotes sustainability. Sustainable hazard mitigation includes the sound management of natural resources and the recognition that hazards and mitigation must be understood in the broadest possible social and economic context. The enhanced planning network called for by DMA 2000 helps local governments articulate accurate mitigation needs, resulting in faster allocation of funding and more cost-effective risk reduction projects.
Figure 1-1: Location of the City of Napa
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1.3.1 Purposes for Planning
This hazard mitigation plan identifies resources, information, and strategies for reducing risk from natural hazards. The City of Napa and the planning committee initiated this planning effort for several key reasons. The City of Napa area has significant exposure to numerous natural hazards that have caused millions of dollars in past damage. The planning committee wants to be proactive in preparing for the probable impacts of natural hazards. Finally, limited local resources make it difficult to implement proactive risk-reduction measures. Federal and state financial assistance is paramount to successful hazard mitigation in the area.
Elements and strategies in the plan were selected because they best meet the needs of the city and its residents. The plan was developed to meet the following objectives:
▪ Meet or exceed requirements of the DMA 2000 and the 2015 California legislation requiring the incorporation of climate adaptation strategies into hazard mitigation planning (SB 379). ▪ Enable the planning committee to continue using federal grant funding to reduce risk through mitigation.
▪ Meet the needs of the City of Napa, as well as meet state and federal requirements. ▪ Create a risk assessment that focuses on City of Napa hazards of concern. ▪ Coordinate existing plans and programs so that high-priority initiatives and projects to mitigate possible disaster impacts are funded and implemented.
1.4 Who Will Benefit from This Plan?
All residents and businesses of City of Napa are the ultimate beneficiaries of this HMP. The plan reduces risk for those who live in, work in, and visit the city, and it provides a viable planning framework for all foreseeable natural hazards that may impact the city. Stakeholder participation helped ensure that plan outcomes will be mutually beneficial. The resources and background information in the plan are applicable citywide, and the plan’s goals and recommendations can lay the groundwork for the development and implementation of local mitigation activities and partnerships.
1.5 How to Use This Plan
This plan includes all federally-required elements of a hazard mitigation plan that apply to the entire planning area. The plan includes the description of the planning process, public involvement strategy, goals and objectives, citywide hazard risk assessment, citywide mitigation initiatives, and a plan maintenance strategy. The plan also includes the following appendices:
▪ Appendix A—Annex Methodology
▪ Appendix B—Planning Process Documentation
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Section 2. What’s New
This section includes background information on the 2015 HMP and this HMP Update. The 2015 mitigation actions were reviewed and have been changed, updated, and revised to reflect new priorities in this HMP. Only the information and data still valid from the 2015 Plan were carried forward as applicable to this HMP update. The sections below describe the planning process for this update. This update profiles the following eight hazards: dam failure, drought, climate change, earthquake, pandemic disease, flood, extreme weather, and wildfire hazards.
2.1 Mitigation Actions
During this HMP update process, each of the 2015 citywide mitigation actions were examined for relevancy, status of the action currently, the potential for future implementation, and potential follow-up.
Some mitigation actions developed during the 2015 HMP effort are an inherent part of the HMP update process or were not detailed enough for implementation at a local jurisdiction level; thus, they were not included in this update. The City made significant changes to other 2015 mitigation actions because of the updated risk assessment and implementation strategy, to include more detail or to update based on current mitigation practices. Table 2-1 provides a record of previous citywide mitigation actions which are no longer active, along with reason for cancellation.
Table 2-1: Cancelled Previous Mitigation Actions
Mitigation
No.
Hazard
Type
Status Year Title/Description Responsible
Party
Reason Cancelled
ma-AH-CN-6 All Hazard Cancelled 2015 Identify and develop programs to be
instituted to assist
residents to prepare for
and recover from a
disaster
Economic
Development
Dept / Fire Dept
Ongoing work of the
City; also included
within MA-AH-CN-3
ma-AH-CN10All Hazard Cancelled 2015 Identify critical
businesses and
prepare emergency
response plans to
protect against
economic loss and
speedy recovery
Building/Econo
mic
Development
Dept / Building
Included within MAAH-CN-6
ma-AH-CN11All Hazard Cancelled 2015 Develop inventories of specific types of
businesses and
buildings and prepare
procedures for postdisaster recovery
efforts
Economic
Development
Dept., IT
Department,
Planning Dept
This action is
included in ma-AHCN-8.
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Mitigation
No.
Hazard
Type
Status Year Title/Description Responsible
Party
Reason Cancelled
ma-AH-CN12All Hazard Cancelled 2015 Prepare a secondary EOC site
Fire
Department,
Utilities
Department,
Information
Technology
Included within MAAH-CN-1
ma-EQ-CN19Earthquake Cancelled 2015 Building Earthquake Safety Program
Community
Development
Department
Included within MAEW-CN-17
ma-EQ-CN21Earthquake Cancelled 2015 Invest in automation and control features on
AC transmission
pipeline to protect
against catastrophic
failures.
Utilities
Department
Included within MAEW-CN-20
ma-EQ-CN22Earthquake Cancelled 2015 Invest in water
transmission pipeline
rehabilitation/replacem
ent to protect against
catastrophic failures
Utilities
Department
Included within MAEW-CN-20
ma-TR-CN33Terrorism Cancelled 2015 Provide training for Public Safety personnel
regarding terrorism
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN34Terrorism Cancelled 2015 Develop training to improve response to
civil unrest and riots
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN35Terrorism Cancelled 2015 Provide terrorism
training
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN36Terrorism Cancelled 2015 Improve response to Mass Casualty/WMD
incidents
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN37Terrorism Cancelled 2015 Increase agency
coordination in dealing
with terrorism
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN38Terrorism Cancelled 2015 Modify and increase resources to decrease
crime
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
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Mitigation
No.
Hazard
Type
Status Year Title/Description Responsible
Party
Reason Cancelled
ma-TR-CN39Terrorism Cancelled 2015 Purchase an armored citizen rescue vehicle
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
ma-TR-CN40Terrorism Cancelled 2015 Improve support of
Napa County
Hazardous Device
Team
Napa Police
Department
Human-caused
hazards not
prioritized in this
HMP; better addressed
in other plans
2.2 New Analysis and Risk Assessment Methodology
The City strengthened this plan by using new research methods and information systems. Most import to the risk assessment was the development of a web-based and interactive Risk Assessment Mapping Platform (RAMP), which has allowed interactive discovery of risk, vulnerability, and exposure data developed especially for the City of Napa. In addition to RAMP, Geographic Information Systems (GIS) mapping and analysis provided the City of Napa with the tools and data to develop more comprehensive data sets than those in the 2015 HMP.
The City also much more clearly tracked described vulnerabilities (referred to as “problem statements” or “areas of concern” in this HMP). The City developed a set of problem statements based off the quantitative risk assessment and lengthy discussions on unmapped vulnerabilities. Mitigation actions were either updated or newly-drafted to address these specific vulnerabilities. Problem statement and mitigation actions tables in Sections 4 and 5 track the connection between problem statement and mitigation action.
This HMP focuses on natural hazards. New HMP mitigation actions focus on four different classifications, including:
▪ Local Plans and Regulations – intended to reduce the city’s vulnerability to future hazard events through the implementation of codes and regulations.
▪ Structure and Infrastructure Projects – intended to protect existing structures by retrofitting, relocating, or modifying the structure to withstand a hazard event. ▪ Natural Systems – to reduce the effects of hazards on the natural resources within a region by preserving or restoring natural areas along with their mitigation functions. ▪ Public Information and Awareness – to advise residents, potential buyers, and visitors about hazards, potentially hazardous areas, and mitigation techniques. 1-26-2022 Submittal EXHIBIT APage 37 of 416
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2.3 Successful Mitigation Activities Since 2015
The 2015 City of Napa HMP guiding principle, goals, objectives, and mitigation actions have been implemented through various on-going projects, plans, and programs. The City has made improvements toward reducing natural hazard risks to life and property, with significant risk reduction efforts for floodplain management, flood damage prevention, and fire hazard reduction. Some examples of these successful policies, programs, and projects are summarized below.
County-wide Community Wildfire Protection Plan (CWPP). The Napa Community Firewise Foundation, with partners including the City of Napa, completed the first county-wide CWPP in 2021 to help Agencies, Fire Safe Councils, Communities, and local homeowners define, plan and prioritize actions to limit damage from the inevitability of wildland fire. The Napa Communities Firewise Foundation (NCFF) is a countywide nonprofit organization that has been operating for 16 years. NCFF's mission is to reduce the risk and impacts of wildfires through fire fuel reduction and community education in Napa County. NCFF supports 12 Fire Safe Councils, manages many local, state and federal grants, and educates communities on such topics as defensible space, home hardening, and fire preparedness.
The CWPP was funded in large part by a CAL FIRE Climate Change Investment Fund Fire Prevention Grant.
The CWPP brings critical partnerships together and identified priority wildfire-related mitigation actions, including several City-specific mitigation actions incorporated into this HMP. For more information, visit https://napafirewise.org/programs/napa-county-community-wildfire-protection-plan/.
Napa Valley Drought Contingency Plan. The City of Napa is the lead agency and convener for the Napa Valley Drought Contingency Plan Task Force (DCP Task Force). The Napa Valley DCP is an outgrowth of the North Bay Water Reuse Authority (NBWRA) that is implementing a regional Title XVI recycled water program. The DCP process prepares local agencies for drought and associated impacts in advance of a crisis. By prioritizing the development of projects and management response actions, the DCP assists local water managers and provides the tools for long-term drought resilience for the region’s water supply. The DCP is currently underway and expected to be completed in 2022.
City of Napa Emergency Operations Plan (2018). The City updates its Emergency Operations Plan (EOP) in 2017-2018, and adopted the EOP in February of 2018. The EOP provides the necessary foundation for the management of emergencies and disasters within the City of Napa and addresses the integration and coordination with the Napa County Operational Area and other governmental levels as needed. Napa County updated its EOP in 2020; the City of Napa is included within the operational area for that EOP as well.
America's Water Infrastructure Act (AWIA) Risk and Resilience Assessment (2020). The City recently updated its Risk and Resilience Assessment, required by the EPA, followed by an Emergency Response Plan due June 30, 2021. Part of the assessment includes an excellent summary of the city’s cyber security needs, estimating short-term needs between one and two million dollars. 1-26-2022 Submittal EXHIBIT APage 38 of 416
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Utilities Hazard Mitigation Efforts. The city Utilities Department has seven HMGP grants at various stages of execution, review by FEMA and Cal OES, or on the waitlist. These projects include updates to generators, pumps and pump stations, water tanks, water transmission lines, and other aspects of the city’s utilities can should be addressed for resiliency during hazard events.
Pump Station Replacement Project. On October 8, 2017, the Atlas Fire destroyed two potable water pump stations which conveyed water to customers within the City’s service area: Hillcrest Pump Station (located on Hillcrest Drive) and Silverado Highlands Pump Station (located above the City’s water treatment plant on Chaparral Circle). During 2020-2021 reconstruction, the City opted for more robust building materials and backup power for each site in an effort to mitigate future damages or service interruptions should another fire or other disaster occur.
Repetitive Loss & the Napa River- Napa Creek Flood Protection Project. The Napa River-Napa Creek Flood Protection Project has been under construction since 2000 by the US Army Corps of Engineers. The project is partially funded by the Measure A, a half-cent sales tax that was passed by Napa County voters in March 1998. The project will restore more than 900 acres of high-value tidal wetlands of the San Francisco Bay Estuary while protecting 2,700 homes, 350 businesses, and over 50 public properties from 100-year flood levels, a savings of $26 million annually in flood damage costs.
The Oxbow bypass is a key part of the project. The bypass is a wet/dry channel that allows for the inundation of high flows from the Napa River during winter months to reduce high flows that would often back up and flood downtown Napa. The bypass includes flood gates to further protect downtown Napa from flooding. The bypass also serves as a community park, Oxbow Commons, which opened in 2015.
In large part because of additional flood protection provided by Oxbow Commons, the City of Napa recently applied to FEMA to have more than 10 repetitive loss properties removed from the floodplain.
Incorporation into other Planning Mechanisms
Figure 2-1: Oxbow Commons and Flood Bypass Project.
Photo Credit: City of Napa
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INTENTIONAL BLANK PAGE
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Section 3. Planning Process
This section describes each stage of the planning process used to develop the HMP. The planning process provides a framework for document development and follows the FEMA recommended steps as enumerated in federal regulation and outlined herein. This HMP is a community-driven, living document. The planning process itself is as important as the resulting plan because it encourages communities to integrate mitigation with day-today decision making. This section describes each stage of the planning process.
The Robert T. Stafford Disaster Relief and Emergency
Assistance Act, as amended by the
Disaster Mitigation Act of 2000 (DMA
2000, 42 U.S.C. § 5165), is intended to
“reduce the loss of life and property,
human suffering, economic disruption,
and disaster assistance costs resulting
from natural disasters.” Under this legislation, state, tribal, and local governments must develop a hazard
mitigation plan as a condition for receiving certain types of non-emergency disaster assistance through FEMA Hazard
Mitigation Assistance. FEMA regulations implementing the DMA 2000 are located at 44 C.F.R. § 201.6 et seq.
FEMA prescribes four major planning steps:
• Step 1: Organize Resources
• Step 2: Assess Risk
• Step 3: Develop a Mitigation Strategy
• Step 4: Adopt and Implement the Plan
The City of Napa followed the FEMA four-step process for this plan. Figure 3-1 provides a detailed, phased breakdown of the planning process that the was completed. These four steps are integrated with a tenstep planning process that FEMA’s Community Rating System uses to establish floodplain management credit, in addition to Flood Mitigation Assistance programs. 1-26-2022 Submittal EXHIBIT APage 41 of 416
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Figure 3-1: City of Napa HMP Planning Process
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STEP 1: Organize Resources
The first step of the HMP planning process was organizing resources, consisting of developing the Planning Team, reviewing relevant existing documents, and organizing public outreach.
Building the Planning Team
The Planning Team was comprised of participants
from the City of Napa who worked together to
develop the HMP. The Planning Team consisted of
a Steering Committee, Planning Committee, a
broader group of residents and regional
stakeholders, and an HMP consultant used for plan
development and facilitation.
Steering Committee
The Steering Committee was at the core of the HMP
planning process and was integral to ensuring the
success of the planning process, its implementation, and future maintenance. Members of the Steering Committee, listed in Table 3-1 below, represented jurisdictional leads from the city and were also a part of the HMP Planning Committee, discussed below.
Table 3-1: HMP Steering Committee
Point of Contact Title
Charlie Rhodes Battalion Chief
Doug DeMaster Senior Civil Engineer, Utilities Department Magdiel Frayre Parks, Trees, and Facilities Supervisor
Jaina French Community Relations and Media Manager
Jeff Gittings Parks and Urban Forestry Management
Julie Lucido Public Works Director
Michael Walker Senior Planner – Advanced Planning
Stephanie Proft Engineering Assistant
Joy Riesenberg Deputy City Manager
Brandon Veyna Fire Prevention/Inspector
City
Residents &
Stakeholders
Planning
Committee
City Steering
Committee
Figure 3-2: City HMP Planning Team
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Planning Committee
The HMP Planning Committee consisted of multiple key decisionmakers with specific expertise to contribute to the planning process from the City of Napa, as well as local and regional stakeholders. The Planning Committee served as liaisons to the greater community. Each member was responsible for communicating the direction and status of the planning effort to their respective departments and constituents and they were expected to represent the perspectives of the city to the Committee.
The Planning Committee was involved in the following planning processes:
▪ Structured coordination and meetings;
▪ Collection of valuable local information and other requested data; ▪ Decision making on plan process and content;
▪ Development of mitigation actions;
▪ Review and comment on plan drafts; and
▪ Coordination of the public input process.
All Planning Committee members did not necessarily attend stakeholder group meetings. Some participated by reviewing draft documents, assisting in the vulnerability assessment, assisting with public outreach, or at other stages of the process. Table 3-2 provides a list of the Planning Committee members.
Documentation of Planning Committee invitations are provided in Appendix B.
Table 3-2: HMP Planning Committee
Name Title Department CRS Expertise
CITY OF NAPA
Charlie Rhodes Battalion Chief City of Napa Fire Department Emergency Services; Natural Resource Protection
Doug DeMaster Senior Civil Engineer Public Works Natural Resource Protection Magdiel Frayre Parks, Trees, and
Facilities Supervisor Real Property Division Natural Resource Protection Jaina French Community Relations
and Media Manager City Manager Public Information
Jeff Gittings Parks and Urban
Forestry Management Parks and Recreation Services Natural Resource Protection Julie Lucido Public Works Director Public Works Property Protection; Structural Flood Control Projects
Michael Walker Senior Planner –
Advanced Planning Community Development Preventative Measures (codes) Stephanie Proft Engineering Assistant Development Engineering Property Protection Joy Riesenberg Deputy City Manager City Manager Preventative Measures (codes) Brandon Veyna Fire
Prevention/Inspector Prevention Property Protection
Phil Brun Utilities Director Utilities Department Public Information Vincent Smith Director Community Development Preventative Measures (codes) 1-26-2022 Submittal EXHIBIT APage 44 of 416
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Name Title Department CRS Expertise
Jason Williams Chief Building Official Building Division Preventative Measures (codes); Property Protection
Steve Brassfield Fire Chief (retired
during process) Fire Department Emergency Services
Zach Curren Fire Chief Fire Department Emergency Services
LOCAL AGENCY
Trent Schager Napa State Hospital
Fire Chief Napa State Hospital Public Information
Paul Warnock Team Leader City of Napa CERT Public information, emergency services
Ken Arnold Napa County CERT Public information, emergency services
Brian Bacinett
Energy &
Environmental
Compliance Specialist
Napa Valley Unified School
District
Public Information; Emergency
Services; Property Protection
Lois Husted
Base/Emergency
Management
Coordinator
Queen of the Valley Hospital Public Information; Emergency Services
LOCAL CITIZEN
Kevin Twohey Napa Resident Public Information
Beth Painter Napa Resident (City
Council Member) Public Information
Christina Benz Napa Resident Public Information
Tim Streblow Gasser Foundation Public Information
NON-GOVERNMENTAL ORGANIZATION
Carol Rice Consultant Napa Communities Firewise
Foundation Natural Resource Protection
Celeste Giunta Director Disasters (COAD) Public information, emergency services
Teri Shore Advocacy Director Greenbelt Alliance Natural Resource Protection; Public Information
REGIONAL AGENCY
Leah Greenbaum Emergency
Management Napa County Property Protection, Emergency Services Kevin Wasiewski Emergency
Management Napa County Property Protection, Emergency Services Frances
Knapczyk
Conservation Program
Manager Napa County RCD Public Information; Property Protection Andrew Damron Technical Services
Director Napa Sanitation Public Information; Property Protection Consultant Team
The City of Napa enlisted a Consultant Team comprised of Dynamic Planning + Science (DP+S) due to its expertise in assisting public sector entities with developing hazard mitigation plans. The Consultant Team facilitated the planning process, collected, and analyzed data, produced meeting materials, and produced 1-26-2022 Submittal EXHIBIT APage 45 of 416
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drafts of the HMP for review. The HMP Consultant Team, as shown in Table 3-3, consisted of a variety of hazard mitigation and certified urban planning professionals.
Table 3-3: HMP Update Consultant Team
HMP Update Project Team HMP Update Project Team Role
Ethan Mobley, AICP Assistant Project Manager
Brian Greer GIS Specialist/Spatial Analyst
Torie Jarvis, JD Outreach Manager, Hazard Mitigation Planner Daniel Spivak Hazard Mitigation Planner
Raini Ott, AICP Hazard Mitigation Planner
Clare Peabody Hazard Mitigation Planner
Alex Krebs GIS Associate
Planning Committee Meetings
The Planning Committee met throughout the development of the updated HMP. Table 3-4 charts those meetings, including date, type, and topics discussed. Meeting documentation, including agendas, hazard maps, PowerPoint presentations, minutes, sign-in sheets, and other relevant handouts, are provided in Appendix B.
Table 3-4: Meeting Summary
Date Meeting Type Topics
August 18th,
2020
Planning Committee
Kickoff Meeting
▪ Welcome and Introductions
▪ Scope Of Work Review
▪ Review Expectations
▪ Explain DMA vs. CRS Public Outreach Processes
▪ Project Schedule
▪ Data Calls/Data Review
November 19th,
2020
Planning Committee
Meeting #1
▪ Welcome and Introductions
▪ Background
▪ Mitigation Planning Defined
▪ Planning Process Review
▪ FEMA Hazard Mitigation Assistance
▪ 2014 Mitigation Plan Review
▪ Outreach
January 14th,
2021
Planning Committee
Meeting #2
▪ Hazard Overview and Draft Risk Assessment Outcomes
▪ Community Asset Inventory Review
▪ Review of Vulnerability Assessment
▪ Capabilities/Resource Assessment
▪ Identify Goals and Policy Priorities
February 10th,
2021
Planning Committee
Meeting #3
▪ Review and Prioritize Draft Mitigation Actions
▪ Develop Implementation Projects
▪ Review Safety Element Goals, Policies, and Programs
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Review and Incorporation of Existing Documents
The Planning Team and Consulting Team reviewed and incorporated existing plans, studies, reports, and technical information in the formation of this HMP. Those documents are cited throughout the hazard profiles in
Section 4.5, and in each hazard profiles’ plans, policies, and regulatory environment section, as well as examined more closely in the Capabilities Assessment in Section 5.3. All documents cited in this HMP are included in Section 7,
Works Cited.
Public Involvement and Outreach
Public involvement is an important and requisite
component of any HMP update. The public outreach
strategy for this update maximized public involvement
throughout the planning process and utilized websites, local media, and community efforts. Due to the unfolding COVID-19 pandemic during the development of this HMP, discussed in detail in Section 4.5.5, all outreach was conducted digitally.
As required by FEMA, the general public was given an opportunity to be involved in the planning process while developing the HMP update through surveys, a project website, and public review periods. Each is described below.
Survey
An eight-question community survey was distributed via the city and Fire Department website, Facebook page, and e-mail blasts. A total of 373 survey responses (including 15 in Spanish) were collected. The results of the survey were used to ensure that the priorities of the city match those of the residents and community members. For example, community members were asked if they believe their property was at risk from a natural hazard disaster; almost 81.8 percent said “yes.” An example survey result is displayed in Figure 3-3, while full results are summarized in Section 5.5.1.2. Full results can be found in Appendix B. 1-26-2022 Submittal EXHIBIT APage 47 of 416
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Figure 3-3: Snapshot of community survey results
HMP Update Website
For this HMP, a project portal at
mitigatehazards.com/napahmp/ served and will
continue to serve as a centralized project information
and file-sharing platform. This website provides a tool for project management, collaborative content, and a
one-stop-shop for mitigation planning resources.
In addition to internal coordination, the project portal played a critical role in public involvement throughout the planning process and documenting public involvement, including the community survey, meetings, and working sessions. Resources such as the Risk Assessment Mapping Platform (RAMP) and links to all meeting summaries are available to the public via the website. Project participants and stakeholders used the website as a project resource for the duration of the planning process and will continue to have access during the five-year update cycle and beyond.
Public Review of Draft HMP
The public reviewed the draft HMP late November and early December, 2021. The City announced the available public draft via their newsletters and social media, and the draft was available at mitigatehazards.com/napahmp/. The public was able to provide comment via a collaborative PDF, an online submission form, or an email. The notice is available in Appendix B. The only public comment received included some small clean-up and edit and confirmation that the climate change section was thorough.
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STEP 2: Assess the Risk
In accordance with FEMA requirements, the Planning Committee identified and prioritized the natural hazards affecting the City of Napa. It also assessed the vulnerability of those identified hazards. Results from this risk assessment aided subsequent identification of appropriate mitigation actions. While the process is described below, the substance of this risk assessment is detailed in Section 4.
Identify and Profile Hazards
Based on a review of past hazard events, existing plans, reports, and other technical studies, data, and information, the Planning Committee determined if regional hazards could affect the planning area. The Planning Committee completed screening and prioritization processes to determine priority hazards to be assessed. A risk assessment finalized the prioritization process by ranking hazards according to the impact and threat to the city.
Assess Vulnerabilities
Assessing vulnerabilities exposes the unique characteristics of individual hazards and begins the process of narrowing down which areas within the City of Napa are vulnerable to specific hazard events. The vulnerability assessment is a GIS overlaying method for examining such vulnerabilities more in-depth.
This exercise was completed by the city and supplemented by meeting and discussing areas of concern regarding each prioritized hazard. The identified hazards were selected for based on the geographic makeup of, priorities of, and services provided by the City of Napa. Using these methods, the Planning Committee estimated vulnerable populations, infrastructure, and potential losses from hazards. Updated content for each hazard profile for the city, including vulnerability, is provided in Section 4.5.
Web-Based Risk Assessment Mapping and Analysis
The web-based and interactive Risk Assessment Mapping Platform (RAMP), accessed via the project website at mitigatehazards.com, allows interactive discovery of risk, vulnerability, and exposure data developed especially for the City of Napa. RAMP is a mapping platform built specifically for mitigation planning. It displays city facilities and buildings overlaid with natural hazards layers to bring interactivity and individual discovery to the GIS analysis performed for the HMP. Figure 3-4 shows the location of RAMP on the project website.
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Figure 3-4: RAMP Access at mitigatehazards.com
The Planning Committee used RAMP to understand vulnerabilities to the City of Napa’s population, critical facilities, and properties exposed to hazards with spatial footprints. Users interactively filter facilities and buildings by natural hazard zones and construction characteristics.
RAMP’s robust data filtering and summation calculations allow the user to understand and visualize vulnerabilities at the facility level with detailed information on the number of structures exposed to various natural hazards. RAMP enables the City of Napa to pinpoint vulnerabilities and reinforces problem statements in the mitigation strategy. Figure 3-5 demonstrates the RAMP web-based interface. 1-26-2022 Submittal EXHIBIT APage 50 of 416
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Figure 3-5: RAMP showing the population of Napa exposed within the FEMA 100-YR Flood Hazard layer STEP 3: Develop a Mitigation Strategy
This plan provides an explicit strategy and blueprint for reducing potential losses identified in the risk assessment based on existing authorities, policies, programs and resources, and the City of Napa’s ability to expand on and improve these existing tools. HMP development included identifying goals, assessing existing capabilities, reviewing the 2015 HMP goals, and identifying new mitigation actions. The HMP was prepared in accordance with requirements from DMA 2000, the California Office of Planning and Research (OPR), and FEMA’s HMP guidance. The process is described below; the substance of the mitigation strategy is detailed in Section 5.
Identify Goals
The Planning Committee reviewed the 2015 HMP goals and determined their current validity, consistent with FEMA requirements. The goals were updated to meet the current hazard environments and to be consistent with the changing policies and goals of the city. The goals are presented in Section 5.4. 1-26-2022 Submittal EXHIBIT APage 51 of 416
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Develop Capabilities Assessment
A capabilities assessment is a comprehensive review of the City of Napa’s capabilities and tools to implement the mitigation actions in the HMP. The Planning Committee identified technical, financial, and administrative capabilities to implement mitigation actions, as detailed in Section 5.3.
Identify Hazard Problem Statements
The Planning Committee developed mitigation actions, as both planning activities and projects, to address problems that could originate from hazards identified in the risk assessment, in line with identified capabilities. Mitigation actions were created first by developing problem statements for prioritized hazards. Best practice is for each hazard problem statement to be mitigated with a combination of shortterm and long-range planning activities, and through both operational and physical projects. Hazard problem statements are located at the conclusion of each hazard profile in table format and are also uploaded in an interactive web-based Mitigation Action Support Tool (MAST), described below. Hazard problem statements for the City of Napa are categorized as impact-related, victim-related, or threatrelated, as described in Figure 3-6.
Figure 3-6: Categories of issues addressed in problem statements ▪ Casualties
▪ Property Damage
▪ Business Interruption
▪ Financial Loss
▪ Environmental
Contamination
▪ School Children in
High Hazard Areas
▪ Care Facilities in High
Hazard Areas
▪ Vulnerable Population
Exposed to Hazards
▪ Increased Fuels due to
Drought
▪ Hotter, Drier Climate
▪ More Intense Storms
▪ Impervious Surfaces =
Greater Runoff
▪ Increases of Invasive
Species
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Identify Mitigation Actions
As part of the HMP planning process, the Planning Committee reviewed and analyzed the status of the mitigation actions identified in the 2015 HMP. The Consultant Team and Planning Committee then worked together to identify and develop new mitigation actions with implementation elements. The Planning Committee prioritized and further detailed the implementation strategies during Planning Committee Meeting #3. Additional detail on these mitigation actions is provided in Section 5.3.
Mitigation Action Support Tool (MAST)
Hazard problem statements and mitigation activities are presented and will be updated through a web interface application developed specifically for the city, creating a living document that can continue to be a valuable resource into the future. The Mitigation Action Support Tool (MAST) is accessible through mitigatehazards.com/napahmp/.
MAST is a web-based interactive tool that enables multiple users to search, view, enter, and update mitigation actions, ideas or projects, and other information. MAST provides Planning Committee and plan reviewers (Cal OES and FEMA) access to valuable mitigation information that can be leveraged by future planning or other risk reduction efforts within the city. The Planning Committee can update the status of their mitigation projects throughout the planning lifecycle, and this web-based tool will improve the City of Napa’s ability to apply for FEMA’s Hazard Mitigation Assistance (HMA) grant programs, including initial grant application processes through Cal OES.
City Planning Processes Library
The City of Napa has completed the HMP planning process per FEMA guidelines. This process is detailed in this section, and it consists of the following elements:
▪ Risk Assessment: The risk assessment measures the potential impact to life, property, and the economy resulting from natural hazards. The intent of the assessment is to identify the vulnerabilities of a community to the greatest extent possible given available data. The risk assessment increases understanding of natural hazard impacts to the community and provides a foundation to develop and prioritize mitigation actions. ▪ View Maps / Download Maps
▪ Hazard Prioritization: The HMP Planning Committee considered and screened a broad set of hazards presented in relevant local, regional, and statewide hazard planning documents. The crosswalk of documents reviewed and the results of screening the relevant hazards to be reviewed are outlined in Section 4.1.1. The HMP then considered past hazard events in the City of Napa to help prioritize hazards to be evaluated in this document, as outlined in Section 4.1.2.d. ▪ View Risk Matrix
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▪ Areas of Concern: The HMP Planning Committee identified the areas of concern and potential impacts of each of the identified hazards on the community. Problem statements were developed for areas of concern, which describe the nature of the consequences or effects of a hazard occurrence on the community and its assets, ensuring the identified mitigation actions are tailored to the specific problems created by various hazard scenarios and are specific to the City of Napa. ▪ View Problem Statements
▪ Capability Assessments: A capabilities assessment consists of an analysis of the existing planning and regulatory capabilities of the city. Planning and regulatory tools typically used by local jurisdictions to implement hazard mitigation activities are building codes, zoning regulations, floodplain management policies, and other municipal planning documents. ▪ View Capability Assessment
Draft HMP
The draft HMP compiled information, data, and associated narratives developed during the above processes for internal and public review periods.
STEP 4: Adopt and Implement the Plan
Once the risk assessment and mitigation strategy were completed, information, data, and associated narratives were compiled into the HMP. Section 2 provides detailed information on new and updated elements of the HMP.
Plan Review and Revision
Once the draft HMP update was completed, a public and government review period was established for official review and revision. Public comments were accepted, reviewed, and incorporated into this update.
Applicable comments from the public have been received and addressed prior to authorization to submit to FEMA and Cal OES. The notice of the public comment period is included in Appendix B.
Plan Adoption and Submittal
This plan has been submitted and approved by FEMA and adopted by the city. Copies of the resolutions are provided in forward of this document.
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Implement, Evaluate, and Revise the Plan
The true worth of any mitigation plan is its implementation and success under FEMA’s grant programs.
This HMP has been assembled to reduce the risk of natural hazards, and also to meet the requirements of the DMA 2000 and maintain eligibility under FEMA’s Hazard Mitigation Assistance (HMA) grant programs.
FEMA administers three programs that provide funding for local agencies with approved mitigation plans:
▪ Hazard Mitigation Grant Program (HMGP), which assists in implementing long-term hazard mitigation planning and projects following a Presidential major disaster declaration. ▪ Building Resilient Infrastructure and Communities (BRIC), which provides funds for hazard mitigation planning and projects on an annual basis.
▪ Flood Mitigation Assistance (FMA), which provides funds for planning and projects to reduce or eliminate risk of flood damage to buildings that are insured under the National Flood Insurance Program (NFIP) on an annual basis.
For more information about FEMA HMA, visit: fema.gov/hazard-mitigation-assistance.
Plan Maintenance
The City will update and monitor this plan in accordance with all FEMA requirements in order maintain eligibility for FEMA HMA. Evaluation and revision procedures for this plan are detailed in Section 6.
Section 6 includes the measures that the City of Napa will take to ensure the HMP’s continuous long‐term implementation, including HMP monitoring, reporting, evaluation, maintenance, and updating. Most of this implementation and maintenance will be done through MAST. Figure 3-7 demonstrates how MAST information will translate into Cal OES Notices of Interest (NOIs) and grant sub-application requests.
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Figure 3-7: MAST elements and Cal OES Grant Applications 1-26-2022 Submittal EXHIBIT APage 56 of 416
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Section 4. Risk Assessment
The risk assessment measures the potential impact on life, property, and the economy resulting from natural hazards. The intent of the risk assessment is to identify the qualitative and quantitative vulnerabilities of a community to the greatest extent possible given available data. The risk assessment increases understanding of natural hazard impacts to the community and provides a foundation to develop and prioritize mitigation actions. In turn, mitigation actions reduce damage from natural disasters through increased preparedness and focus resources to areas of greatest vulnerability.
This risk assessment section evaluates potential loss from a hazard event by assessing the vulnerability of buildings, infrastructure, and people. It identifies the characteristics and potential consequences of hazards, explores how much of the city could be affected by a hazard, and assesses the impact on city assets. The risk assessment approach consists of three components:
▪ Hazard Identification and Screening (Section 4.1)
▪ Hazard Prioritization (Section 4.1.3)
▪ Vulnerability Assessment and Hazard Profiles (Section 4.5) Other sections provide background and context for the risk assessment. Section 4.3 provides a geographic and demographic overview of the City of Napa. Section 4.4 explains the methods utilized in the risk assessment.
4.1 Hazard Identification and Screening
Per FEMA guidance, the first step in developing the risk assessment is identifying the hazards. This step includes two parts. First, the HMP Planning Committee considered and screened a broad set of hazards presented in relevant local, regional, and statewide hazard planning documents. This section describes documents reviewed and the results of screening the relevant hazards and past hazard events in the City of Napa to help prioritize hazards to be evaluated in this document. 1-26-2022 Submittal EXHIBIT APage 57 of 416
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4.1.1 Hazard Screening
The City’s HMP Planning Committee first reviewed previously-prepared hazard mitigation plans and other relevant documents to determine the realm of natural hazards that have the potential to affect the city and the nearby region. Table 4-1 provides a crosswalk of hazards identified in the 2015 City of Napa HMP, the current City of Napa General Plan, and the 2018 California State Hazard Mitigation Plan. This document review identified 18 different hazards. The crosswalk was used to develop a preliminary hazards list, providing a framework for HMP Planning Committee members to evaluate which hazards were truly relevant and which ones were not. For example, volcanoes were considered to have no relevance to the City of Napa, while earthquake, flood, dam failure, landslide, and drought were indicated in every hazard document.
Table 4-1: Document Review Crosswalk
Hazards
2015 City of Napa
HMP Update
1998 City of Napa
General Plan Update
(With 2015 Adoptions)
2018 California State
HMP
Agricultural Pests ■
Climate Change ■ ■
Dam Failure ■* ■ ■
Drought ■ ■ ■
Earthquake ■ ■ ■
Flood ■ ■ ■
Insect Hazards
Landslide ■
Levee Failure ■
Manmade Hazards ■
Pandemic Disease ■* ■
Sea-level rise ■
Extreme weather ■
Soil Hazards ■ ■
Terrorism & Tech Hazards ■ ■
Tsunami ■
Volcano ■
Wildfire ■* ■ ■
* Not profiled but mentioned and mitigation actions included.
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Table 4-2: Hazard prioritization
Hazard Type Explanation
Climate Change High priority city-wide, profiled hazard.
Dam failure High priority city-wide, profiled hazard.
Drought High priority city-wide, profiled hazard.
Earthquake/ Geologic Hazards High priority city-wide, profiled hazard.
Flood High priority city-wide, profiled hazard.
Hazardous Material While hazardous materials can release and impact the city, there are better avenues to address this hazard outside this plan.
High Winds/ Straight Line Winds High priority city-wide, profiled as part of Extreme Weather.
Insect Hazards While hazardous insects exist in the City of Napa, this was not considered a priority within the city and is not profiled in this plan.
Pandemic Disease* High priority city-wide, profiled hazard.
Extreme Weather, including: High priority city-wide for high wind, heavy rain, and high heat.
Extreme Heat Profiled as part of Extreme Weather.
Hail Hail events are rare and not considered a priority.
High Wind Profiled as part of Extreme Weather.
Heavy Rain Profiled as part of Extreme Weather.
Fog Fog events are rare and are not considered a priority.
Lightning Not a priority as an extreme weather event; discussed as source of wildfire.
Severe Thunderstorm Severe thunderstorms were not identified as a priority in this plan.
Winter Storm / Extreme Cold/
Freeze Events
Winter storms are rare in the City of Napa and not identified as a priority for this plan.
Slope Failure Slope failure events are rare and not considered a priority for the City of Napa.
Soil Hazards
While limited soil hazards exist in the City of Napa (erosion and shifting soils), these are not prioritized in this plan. Erosion discussed, as relevant, under the flood hazard.
Terrorism/Human Caused Threats While terrorism is certainly a threat to the city, it is best addressed in other plans as this HMP does not address human-caused threats.
Tornado Impacts to the City from tornados are extremely unlikely, if any.
Volcanic Activity Due to distance from volcanoes and the limited chance of an eruption, this hazard was not identified as a priority.
Wildfire High priority city-wide, profiled hazard.
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4.1.2 Past Major Hazard Events
One important consideration in identifying and prioritizing hazards is past major hazard events, especially those that triggered federal or state disaster declarations. The HMP Planning Committee reviewed and considered past major hazard events in the City of Napa as part of the screening and identification process.
Most available information on major past hazard events comes from federal or state disaster declarations.
These declarations may be granted when the severity and magnitude of an event surpasses the ability of the local government to respond and recover. Additional federal or state disaster funding (or both) is generally available in response to a disaster declaration. State funding assistance is provided when a local government’s capacity to respond to the disaster is exceeded. 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.
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 do not include the long-term federal recovery programs that accompany major disaster declarations. Quantity and types of damage are the determining factors.
The County of Napa has received 33 federal disaster declarations since 1953, many of which impacted the City of Napa, and some of which were statewide, including:
11 Wildfires 5 Floods
12 Extreme Weather Events 1 Drought
2 Earthquakes 2 Biological Events
Extreme weather and flooding events are most likely to occur in the winter months, with 25 of the 54 federally-declared disasters occurring in January and February. Wildfires have typically occurred in late summer and fall, with 188 wildfire declarations from July through October. Table 4-3 lists federal disaster declarations in Napa County since 1953.
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Table 4-3: Disaster Declarations in Napa County 2000- present Year Incident Description Disaster Number
2020 Covid-19 EM-3428
2020 Covid-19 Pandemic DR-4482
2020 LNU Lightning Fire Complex FM-5331
2020 Wildfires DR-4558
2019 Severe Winter Storms, Flooding, Landslides, and Mudslides DR-4434 2019 Severe Winter Storms, Flooding, Landslides, and Mudslides DR-4431 2017 Atlas Fire FM-5214
2017 Patrick Fire FM-5222
2017 Severe Winter Storms, Flooding, and Mudslides DR-4308 2017 Severe Winter Storms, Flooding, and Mudslides DR-4305 2017 Severe Winter Storms, Flooding, and Mudslides DR-4301 2017 Tubbs Fire FM-5215
2017 Wildfires FM-4344
2015 Valley Fire FM-5112
2015 Wragg Fire DR-4193
2014 Butts Fire FM-5057
2014 Earthquake DR-4193
2008 Wildfire FM-2776
2006 Severe Storms, Flooding, Landslides, and Mudslides DR-1646 2006 Severe Storms, Flooding, Mudslides, and Landslides DR-1628 2005 Hurricane Katrina Evacuation EM-3248
2000 Earthquake DR-1342
Source: FEMA Disaster Database via mitigatehazards.com/hazard-mapping/ , accessed 12/22/2020.
Drought declarations may also occur through the USDA, as agricultural areas near the City of Napa can be particularly impacted by drought. A USDA disaster declaration certifies that the affected county has suffered at least a 30-percent loss in one or more crop or livestock areas and provides affected producers with access to low-interest loans and other programs to help mitigate the impact of the drought.
Importantly, all counties neighboring those receiving disaster declarations are eligible for the same assistance.
Hazard events occurring outside Napa County boundaries also can directly and indirectly impact the City of Napa. For instance, dam failures and wildfires may occur outside the City of Napa but affect watersheds that drain into the city or watersheds from which the City gets its water supply. These hazard events may still result in flooding and longer-term watershed health impacts. Power supply also could be interrupted by hazard occurrences outside of the city.
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4.1.3 Compounding Hazard Events
This HMP examines the vulnerabilities of hazard events in the City of Napa individually; however, hazards occur in combination as well. Frequently, another hazard occurs as a secondary hazard, such as an earthquake triggering a landslide or tsunami, or severe rain events following a wildfire causing debris flows. Other events are compounded by outside factors, such as wildfire evacuations occurring during Public Safety Power Shutoff (PSPS) events. This hazard mitigation plan highlights multiple hazard risks within the hazard profiles by highlighting secondary hazards and, for wildfire in particular, highlighting local compounding conditions that accelerate wildfire impacts, such as PSPS events. See Section 4.5.8.1.
The compounding of the ongoing COVID-19 pandemic with another hazard event is particularly concerning. Local governments are actively considering response and mitigation needs that can help reduce the impacts of a multiple-hazard event that include pandemics and another hazards, such as flood, earthquake, or wildfire. Many of the problems and mitigation actions explored herein take this emerging issue into consideration. For more on pandemic and its impact on other hazards, see Section 4.5.5.6. 1-26-2022 Submittal EXHIBIT APage 62 of 416
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4.2 Hazard Prioritization
The Planning Committee’s hazard prioritization process combines historical data, local knowledge, and consensus opinions to produce a matrix that illustrates whether each profiled hazard is an extreme, high, or medium priority. The criteria below were used to evaluate hazards and identify the highest risk hazard in the City of Napa. The results of the prioritization process for the City of Napa are shown in Figure 4-1. The following questions and guidance shaped the ranking on the matrix:
Probability
What is the likelihood of a hazard event occurring in a given year? ▪ Unlikely: Less than 1% annual probability or occurs rarely in the region or community. ▪ Possible: 1%-10% annual probability or could occur. Uncommon in the region or community. ▪ Likely: 10%- 100% annual probability or recurrent. Not frequent in the region or community. ▪ Highly likely: 100% annual probability or occurs frequently in the region or community.
Impact
In terms of injuries, damage, or death, would you anticipate impacts to be minor, limited, critical, or catastrophic when a significant hazard event occurs?
▪ Minor: Very few injuries, if any. Only minor property damage and minimal disruption on quality of life. Temporary shutdown of critical facilities.
▪ Limited: Minor injuries only. 10%-25% of property in affected area damaged or destroyed. Complete shutdown of critical facilities for more than one day.
▪ Critical: Multiple deaths or injuries possible. 25%-50% of property in affected area damaged or destroyed. Complete shutdown of critical facilities for more than one week. ▪ Catastrophic: High number of deaths or injuries possible. More than 50% of property in affected area damaged or destroyed. Complete shutdown of critical facilities for 30 days or more. 1-26-2022 Submittal EXHIBIT APage 63 of 416
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Figure 4-1: Prioritized Hazard Assessment Matrix for the City of Napa 1-26-2022 Submittal EXHIBIT APage 64 of 416
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4.3 City of Napa Geographic and Demographic Profile
The geographic and demographic profile for the City of Napa sets context for the vulnerability assessment accompanying each hazard profile in Section 4.5. Paired with vulnerability assessments, the regional profile can help guide resources and mitigation strategies to key populations and geographic areas. The Planning Committee reviewed geographic and demographic data as part of the update process.
4.3.1 Geography
The City of Napa is located adjacent to the Napa River in the southern portion of the Napa Valley, 52 miles northeast of San Francisco and 61 miles west of Sacramento. Figure 4-2 displays a city geographic overview.
A majority of the city lies on relatively level ground; however, the eastern and western edges of the city extend into brush and oak-covered foothills. The city’s northern edge transitions into agricultural lands, primarily vineyards. The southern end of the city abuts agricultural and marsh lands, as well as the Napa County Airport.
The major surface hydrologic feature of this area is the Napa River. The Napa River flows from Mount St.
Helena and winds through the level valley floor between the Howell Mountains to the east and the Mayacamas to the west, passing through the City of Napa on its way to San Pablo Bay. The river runs approximately 40 miles in length through mountains, vineyards, pastures, urban and industrial development, and marshlands. All but the southern 3.4 miles of the river lie in Napa County. In 1950, the U.S. Army Corps of Engineers (COE) completed a navigation channel, making the river navigable from San Pablo Bay to Third Street in downtown Napa. The Napa River drains a watershed encompassing approximately 426 square miles. The Napa River is fed by eight tributaries, the most significant of which is Napa Creek, which drains approximately 15 square miles of watershed before merging with the Napa River at the First Street Bridge. The city has a long history of flooding from the Napa River and its tributaries, as described in more detail in the Flood Hazard Profile, Section 4.5.6.
Within the boundaries of the city limits, there are several unincorporated islands which remain under Napa County jurisdiction, particularly in the Terrace Shurtleff and Pueblo planning area. (City of Napa, 2015) The planning boundary for the City of Napa’s General Plan is the Rural Urban Limit (RUL), encompassing approximately 18.2 square miles. The RUL represents the city’s planned ultimate boundary for urban development. The RUL is apportioned into 12 planning areas of generally related neighborhoods and commercial and industrial areas, for the purposes of more localized planning. They include Linda Vista, Vintage, Browns Valley, Pueblo, Beard, Alta Heights, Westwood, Central Napa, Soscol, Terrace/Shurtleff, River East, and Stanly Ranch. (Id.)
The city’s water division provides water outside of city boundaries. The water division geographic overview is shown in Figure 4-3. Vulnerability information for water division infrastructure outside of city boundaries is shown in RAMP but is not calculated in this HMP vulnerability assessment. 1-26-2022 Submittal EXHIBIT APage 65 of 416
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Figure 4-2: City of Napa Geographic Overview
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Figure 4-3: Napa Water Division Overview
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4.3.2 Climate
Napa enjoys a moderate climate due to cooler temperatures in the San Francisco Bay. Representative January temperatures for the City of Napa are 37.4 degrees Fahrenheit (°F) minimum and 57.7°F maximum. For July, they are 52.2°F minimum and 82.1°F maximum. Average rainfall is 23.88 inches per year, with the majority occurring from November to March. Summer is typically the dry season, resulting in the highest wildfire risk in the surrounding areas in late summer and fall.
4.3.3 Demographics and Vulnerable Populations
Natural disasters are social phenomena as well as meteorological or physical events. The City of Napa’s demographic profile is important to understanding how the impacts of hazard events will be distributed throughout the community, especially groups with underlying vulnerabilities that create obstacles to disaster preparedness, response, and recovery. Understanding the unique social and economic fabric of an area can also help to identify potential social costs of damage to infrastructure such as housing, industry, public facilities or otherwise essential services, and transportation.
The United States Census Bureau estimated the City of Napa’s population to be 79,782 in 2017, an 3.7% increase from 2010 population levels; the statewide population growth rate over that same period was 4.6%. (United States Census Bureau, 2017)
4.3.3.1 Introduction to Vulnerable Populations
Demographics help identify which populations may be particularly vulnerable to hazard events. Some populations are at greater risk because of age, resources, physical abilities, or other factors. Vulnerability in the face of a hazard event is not a fixed characteristic; the same individual may be at risk for some hazards but not others. For example, a low-income family without a car may be at risk for a wildfire or flood where a quick evacuation is necessary, but adequately prepared for an earthquake. Some individuals can reduce their personal vulnerability through mitigation, whereas others face more permanent vulnerability in the face of disaster; this is especially true for individuals who rely on caregiving networks to navigate daily life, such as children, the elderly, and persons with disabilities (National Center for Disaster Preparedness, 2020) Inequality in the distribution of environmental risk means that vulnerable populations may also live in more hazard-prone areas..
In the context of all-hazards preparedness and response planning, at-risk individuals (often used interchangeably with “vulnerable populations”) are defined federally as “children, pregnant women, senior citizens, and other individuals who have access or functional needs in the event of a public health emergency.” (42 U.S.C. § 2802(b)(4)(B)(2019)) Examples may include (but are not limited to) persons:
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▪ with disabilities ▪ who lack transportation
▪ living in institutional settings ▪ experiencing homelessness ▪ from marginalized communities ▪ with chronic medical conditions ▪ who have limited English proficiency or are
non-English speaking
Communities may be able to reduce the vulnerability of certain populations by increasing the adaptive capacity of affected communities. Examples include cost-sharing to reduce fuels, stabilize structures, or implement flood-reducing measures or educational programs offered in English and Spanish and targeted to specific populations. Planning for vulnerable populations in hazard mitigation can help prioritize resources where they will be the most effective. This section explores the various demographic and economic circumstances surrounding common vulnerable populations.
4.3.3.2 Income & Housing
Economic mobility is one of the most important factors in natural hazard vulnerability. Low-income residents are more likely to occupy housing which is inadequately maintained or otherwise poorly built to withstand extreme events. For example, mobile or modular homes are more susceptible to damage in earthquakes and floods than other types of residences. In urban areas, low-income residents often occupy older homes and apartment complexes with unreinforced masonry, which is particularly susceptible to seismic damage. Renters are also more vulnerable to natural hazards, as they are less likely to take out property insurance, and the decision to make major structural improvements typically lies with the property owner. Federal disaster recovery services can exacerbate inequality between renters and homeowners; from 1999 to 2013 U.S. homeowners saw their wealth increase with local hazard damages, whereas renters’ wealth decreased. (Howell & Elliot, 2019) Figure 4-4: Owners and Renters
Source: 2012 – 2017 American Community Survey (ACS) 5-Year Estimates
53.0% 40.4%
0.0% 25.0% 50.0% 75.0% 100.0%
Owner Occupied
Renter Occupied
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Low-income households and communities face disproportionate financial burden from costs associated with disaster preparedness, response, and recovery. Disasters create unexpected expenses which may serve as “tipping points” for families and individuals living on the edge of poverty or homelessness.
Recovery costs may be higher for those without resources to conduct hazard mitigation activities ahead of time. Families and individuals who lack access to transportation may be unable to evacuate ahead of an emergency. (Krause & Reeves, 2017)
Low-income residents and renters are also less likely to purchase insurance, meaning that those with the most to lose during an event are also the least prepared to deal with potential losses. Major hurricane events in recent history such as Harvey, Irma, and Katrina all demonstrate that low-income and/or historically marginalized communities face increased vulnerability to hazard events, and struggle to recover the most. (Id.)
Table 4-4 shows the median household income for the city. The “median” is the value that divides the distribution of household income values into two equal parts (using the “mean”, or average, as a summary statistic would result in a value weighted towards the highest-income “outlier” households). The median household income in the City of Napa from 2012-2017 (in 2017 dollars) was $75,341, compared to $60,366 across the U.S. (United States Census Bureau, 2017) Eight percent of the city’s population was living in poverty, lower than the national rate of 12.3% during the same year.
Table 4-4: Household Income and Poverty Levels
Jurisdiction Total Population Persons in Poverty Total Households Median Household
Income
(Avg. in Jurisdiction)
Napa City 79,722 6,340 (8%) 30,296 $75,341
Source: 2013-2017 American Community Survey 5-Year Estimates Figure 4-5 shows median income data by census tract; the highest income census tracts are located in the hills on the eastern and western sides of Napa Valley, as well as in the northern part of the main city corridor. Middle and lower income tracts are distributed more centrally along State Routes 29 and 121. 1-26-2022 Submittal EXHIBIT APage 70 of 416
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Figure 4-5: City of Napa Median Household Income Distribution 1-26-2022 Submittal EXHIBIT APage 71 of 416
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4.3.3.3 Age
Children and the elderly may be more vulnerable during an extreme hazard event. Specific planning attention for the elderly is an important consideration, especially given the current aging of the American population. Indeed, 28% of households in the City of Napa include at least one senior individual, 8% of whom experience poverty. Vulnerability among persons in the same age cohort varies significantly based on health, age, and economic security; nevertheless, senior residents as a group have a higher prevalence of physical and financial barriers to response and recovery, both during and after an emergency.
Seniors living alone may have more difficulty evacuating, especially for individuals with mobility challenges and those who lack internet access and/or internet fluency. Persons over 65 living alone compromise 12.6% of all households in the City of Napa. Assisted-living facilities usually require extra notice and coordination to implement evacuation and are typically identified as “critical facilities” by emergency managers. This plan identifies 36 residential senior care facilities in city limits, which are included as a part of the damage estimate for hazard-specific profiles in section 4.5.
In addition to physical limitations, an overall higher prevalence of chronic medical conditions among seniors also translates to exacerbated health risks for specific disasters, including smoke from wildfires and extreme temperatures in either direction. This underlying vulnerability of senior residents to natural hazards is compounded by financial hardship. In the city, 7.5% of households with at least one senior member experience poverty.
Table 4-5: Senior Households
Jurisdiction Total Households
Total Households
w/ 65+
Households w/
65+ Living Alone
Households w/
65+ Living in
Poverty
Napa City 30,296 8,499 (28.1%) 3,815 637
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Children as well as seniors often depend on family and caregivers to navigate daily life. As such, their wellbeing during and after a natural disaster is only as resilient as the networks of care upon which they rely. Over a third of households in the City of Napa include minors, one-fourth of which represent singleparent families. Additional outreach efforts and resources may be necessary to protect the most vulnerable residents of the community by maintaining resilient care networks prior to and after a disaster.
Table 4-6: Households with Minors <18
Jurisdiction Total Households
Households w/ Minors
<18
Single Parent
Households with
Minors <18
Napa City 30,296 9,669 (31.9%) 2,383
Source: 2013-2017 American Community Survey 5-Year Estimates Figure 4-6 and Figure 4-7 show the geographic distribution of population of seniors over 65 and minors under 18 throughout the City of Napa. Similarities are present between the highest concentration of minors and families along the main highway 29 corridor, and the low to moderate income census tracts identified in Figure 4-5. The inverse is mostly true for the senior population, with higher concentrations of senior residents in the eastern and western hillside areas of the city and to the north along the main valley corridor. Conducting proactive outreach for seniors living in hilly areas of wildlife urban interface (WUI) could help to identify residents who may need assistance during evacuations ahead of an emergency. 1-26-2022 Submittal EXHIBIT APage 73 of 416
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Figure 4-6: City of Napa Population Under Age 18
Figure 4-7: City of Napa Population Over Age 65
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4.3.3.4 Race, Ethnicity and Language
Natural disasters compound racial disparities, and non-white individuals and communities receive less recovery aid from FEMA than their white counterparts, even where the amount of damage is the same. (Billings, Gallagher, & Ricketts, 2019) (Domingue & Emrich, 2019) At the time of this plan’s publication, the ongoing COVID-19 pandemic is a glaring testament to racial and ethnic disparities in disaster outcomes, with non-white persons facing morbidity rates from COVID-19 infections anywhere from 70 to 350% higher than white, non-Hispanic persons. (Centers for Disease Control and Prevention, 2021) Majority-Black, Hispanic, and Native American census tracts additionally face a 50% greater vulnerability to wildfire compared to other census tracts. (Levin, Phil; Davies, Ian, 2019) These disparities are evidence not of intentionally biased policy design, but rather the complicated relationship between disaster recovery and overlapping social vulnerabilities including race, income, language, and health. Communities with more nonwhite residents may have lower tax revenue and property values, which means less investment in mitigation and rebuilding efforts before and after an emergency. Nonwhite residents are also more likely to be low income and renters, conditions which create barriers to navigating FEMA individual assistance programs.
According to the 2013-2017 American Community Survey estimates, the City of Napa is predominately white, at 76% of the total population. The largest minority population is Hispanic or Latino, at 40% of the total city population. This percentage includes other applicable race categories. See Figure 4-9 for the racial distribution within the City of Napa and a source note explaining the percentage estimates.
Individuals with no or limited English-speaking ability may have difficulty understanding evacuation information and navigating recovery programs. According to 2013-2018 American Community Survey estimates from the U.S. Census, approximately 18% of total households in the city are Spanish-speaking, with one-third of those households speaking English “less than very well”. Farm workers may be particularly vulnerable during a hazard event, especially those with language and/or transportation barriers, or those living in temporary worker housing. (California Employment Development Department, 2019) (U.S. Dep't of Ag, 2017)
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Figure 4-8: Household Language
Source: 2013-2017 American Community Survey 5-Year Estimates Figure 4-9: City of Napa Race Distribution 2012-2017
Source: 2012-2017 American Community Survey
Note: Hispanics may be of any race, so are included in applicable race categories. This has the effect of influencing total population percentage. (a) Includes persons reporting only one race. (b) Hispanics may be of any race, so also are included in applicable race categories.
6% 18%
0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20%
0% 5% 10% 15% 20%
Spanish
Spanish Spanish (Limited English)
76%
40%
1%
1%
3%
0.2%
3%
0% 25% 50% 75% 100%
White
Hispanic (b)
Black or African
American (a)
American Indian &
Alaska Native (a)
Asian (a)
Native Hawaiian &
Other Pacific Islander (a)
Two or More Races
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4.3.3.5 At-Risk Individuals with Access and Functional Needs Access and functional needs may interfere with the ability to access or receive medical care before, during, or after a disaster or emergency. Irrespective of a specific diagnosis, status, or label, the term “access and functional needs” refers to a broad set of cross-cutting needs, generally distinguished into access-based or function-based according to the following:
▪ Access-based needs require that resources are accessible to all individuals, such as social services, accommodations, information, transportation, and medications to maintain health. ▪ Function-based needs refer to restrictions or limitations an individual may have that requires assistance before, during, or after a disaster or public health emergency.
At-risk individuals may have additional needs that must be considered in planning for, responding to, and recovering from a disaster or emergency. A recommended approach for integrating the access and functional needs of these individuals is to consider elements based on the following “CMIST” framework:
▪ Communication – Individuals who may have limitations that interfere with the receipt of and response to information require information to be provided in an appropriate and accessible format. This can include individuals who are deaf or hard of hearing, individuals who speak American Sign Language, individuals who have limited or no English proficiency, individuals who are blind or have low vision, and individuals who have cognitive or physical disabilities. ▪ Maintaining Health – Individuals who may require Personal Assistance Services (or personal care assistance) in maintaining their activities of daily living, such as eating, dressing, grooming, transferring, and toileting.
▪ Independence –Individuals who function independently with the help of assistive devices, such as consumable medical supplies (e.g., diapers, formula, bandages, ostomy supplies, etc.), durable medical equipment (e.g., wheelchairs, walkers, scooters, etc.), or service animals. ▪ Services and Support – Support for individuals with behavioral health needs or psychiatric conditions such as dementia, Alzheimer's disease, Schizophrenia, etc; those who require regular medical attention, and individuals living with chronic illness; and those who otherwise rely on caregiving to navigate daily life, including infants minors. ▪ Transportation – Individuals with transportation needs due of age, disability, temporary injury, addiction, legal restriction, or those who do not have access to a vehicle. This requires coordination to ensure access to mass transit and accessible vehicles, such as para-transit. (U.S. Department of Health & Human Services, 2016)
While most individuals with access and functional needs do not have acute medical needs requiring the support of trained medical professionals, many will require assistance to maintain health and minimize preventable medical conditions. These individuals may require more time and assistance during an evacuation. It is estimated that almost 5% of people over age 65 have some form of disability, as shown in Table 4-7. (American Community Survey, 2013-2017) These individuals warrant special attention from planners and emergency managers.
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Table 4-7: Disability Status of Non-Institutionalized Population in the City of Napa in 2013-2017 Jurisdiction Total
Population
Persons
with a
Disability
Under 18 18-64 65+
City of Napa 79,722 8,291 (10%) 657 (1%) 3,838 (5%) 3,796 (5%) Source: 2013-2017 American Community Survey
4.3.4 Economy
City of Napa has strong ties to Napa County's agricultural economy because of its location in the Napa Valley American Viticultural Area (AVA). Wine grapes account for 99 percent of all agricultural output in Napa County. Red grape varietals are dominant in the region, with a total value that is five times than that of white grape varietals. Protecting the wine industry, and the tourism it generates, is vital to the city's economy. In addition to core agricultural and tourism industries, there are a number of major employers, such as the Napa State Hospital, Queen of the Valley Medical Center, Kaiser Permanente, and Napa Valley College, that provide the city with a solid economic foundation. (City of Napa, 2020) The City of Napa generates its own service economy, with a large retail sector and significant employment in local government and schools.
Napa's economy is a part of and influenced by the broader region, which includes the San Francisco Bay area. Approximately 42 percent of City of Napa residents commute to jobs outside of Napa County. Most people who commute to work outside the county are concentrated in professional industries, with 73 percent making over $100,000 annually. Tourism, one of the area’s more important industries, is largely dependent on Bay Area residents. Napa Valley’s reputation as a premier hospitality and viticulture destination produced an increase of 600,000 visitors to the area between 2012 and 2016. (Bay Area Council Economic Institute, 2019).
The City of Napa has a difficult time maintaining housing affordability, like most of the region.
Approximately 39 percent of Napa County residents spend more than 30 percent of their income on housing costs. However, the city and county offer comparatively lower median home costs than San Mateo, San Francisco, and Santa Clara counties. Napa County’s median home price is $665,000, approximately half of the median home prices of those three counties. (Id.) The city’s economy is in large part driven by small businesses. Employment in public administration, accommodation and food services, healthcare, retail, and manufacturing made up more than 60 percent of the jobs located within the city in 2017. Employment is also concentrated in establishments with fewer than 10 employees, comprising 72 percent of the city’s jobs. The city's major business park at the south end of the city has begun to attract some high-tech businesses as well as medical research, food distributors, and other related facilities. The county's business park, located near the Napa County airport south of the city, has also attracted a wide variety of uses, including warehousing, food processing, and agriculturalrelated industries. Table 4-8 lists the top sectors within the City of Napa. (Id.) 1-26-2022 Submittal EXHIBIT APage 79 of 416
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Table 4-8: Top Sectors in City of Napa, 2017
City of Napa Employment by NAICS Sector, 2017 Number of Employees % Total of Napa County Public Administration 8,289 78%
Accommodation and Food Services 6,258 53%
Health Care and Social Assistance 5,983 71%
Retail Trade 4,569 71%
Manufacturing 4,063 32%
Administrative and Waste Services 3,299 76%
Construction 3,061 75%
Agriculture 2,793 56%
Other Services, Except Public Administration 1,500 70%
Professional and Technical Services 1,469 71%
Finance and Insurance 1,195 86%
Transportation and Warehousing 1,173 66%
Wholesale Trade 990 59%
Arts, Entertainment, and Recreation 795 73%
Real Estate and Rental Leasing 588 67%
Total 47,488 62%
Source: California Employment Development Department, recreated from the Bay Area Council Economic Institute
4.3.5 Past and Future Trends in Development
The City of Napa has experienced significant economic growth and diversification over the last several decades. Beginning in the 1970s, both the City and County began to diversify their economies by seeking to attract a variety of business types to major "corporate parks.” The city's major business park at the south end of the city has begun to attract some high-tech businesses, as well as medical research, food distributors, and other related facilities. The county's business park has also attracted a wide variety of uses, including warehousing, food processing, and agricultural related industries. The City of Napa is projected to continue substantial growth over the next 20 years, adding almost 10,000 people and 9,000 jobs in the City between 2020 and 2040. (ABAG, 2017) In the more near-term, tourism growth is booming with a projected 85% increase in lodging during this HMP planning period (2021-2026). (Economic & Planning Systems, Inc., 2019)
Development in the last few decades has occurred with minimized hazard risk because of existing overlay of federal, state, and local regulation. First, the city’s general plan (GP) serves as a blueprint for establishing long-range development policies. A GP provides a basis for private development proposals and public projects to remain consistent with existing city, regional and state policies. The GP is designed to help the City of Napa address issues related to land use, circulation (traffic), housing, open space, conservation, noise, and safety. The Land Use Element of the plan helps guide the city in determining the location of future development, to include possible future annexations for municipal jurisdictions. The Safety 1-26-2022 Submittal EXHIBIT APage 80 of 416
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Element of the GP serves to decrease risk of impact from natural hazards through multiple required components and subsections, including health and public safety as required by the California State Law.
The City is currently updating its general plan, including the land use and safety elements, and this hazard mitigation plan will be integrated into that update. See Napa2040.com.
While past development has occurred in hazard areas and increased hazard risks to some degree, development standards and performance measures, oftentimes incorporated into specific plans, are now employed to reduce risk. These development standards are continually being improved and will continue to be strengthened in the future.
The City of Napa has gone to great lengths to ensure future development within hazard areas is minimized and mitigated to the greatest extent possible. Section 5.3, the capabilities and adaptive capacity assessment, explains those proactive steps in greater detail. Buildings are increasingly more resilient to hazards through California’s building codes, some of the strongest in the country. Nationally, building codes have continually improved disaster resilience and, since 1990, those great improvements have only added about one percent to construction costs. (National Institute of Building Sciences, 2019) 1-26-2022 Submittal EXHIBIT APage 81 of 416
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4.4 Vulnerability Assessment Methods
This section provides an overview of the methods used in the vulnerability assessments in Section 4.5.
Vulnerabilities to each hazard are assessed in a two-step process, as outlined in this section. First, population, critical facilities, and county parcels are inventoried to develop a “lay of the land.” Second, the inventories are used to calculate estimated exposure and damage from hazards at various levels of severity. A more detailed explanation of the methodology is included in Appendix A.
The vulnerability assessment utilizes geospatial data along with local knowledge of past events.
Geospatial data is essential in determining population and assets exposed to hazards identified in this plan. Geospatial analysis can be conducted if a natural hazard has a spatial footprint that can be analyzed against the locations of people and assets. In the City of Napa, dam failure, flooding, earthquake, and wildfire have identifiable geographic extents and corresponding spatial information about each hazard.
Figure 4-10 illustrates the data inputs and outputs used to create the vulnerability analyses for each hazard in Section 4.5.
Figure 4-10: Data Source and Method
4.4.1 Population and Asset Inventory
To describe vulnerability for each hazard, it is important to first understand the total population and total assets at risk. Population and asset inventories provide a baseline to measure the vulnerability to people and assets for natural hazard events. Asset inventories can also be used to estimate damages and losses expected during a “worst-case scenario” event for each hazard. The following describes the total population, critical facilities, and parcel inventory inputs. 1-26-2022 Submittal EXHIBIT APage 83 of 416
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4.4.1.1 Population
An initial step in producing the hazard-specific vulnerability assessments is to determine the population near each natural hazard. Each natural hazard scenario affects the City residents differently depending on the location of the hazard and the population density of where the hazard event could occur. For hazards that potentially affect the whole City such as earthquake or drought, the vulnerability assessment assumes 78,130 persons or 100% of the City’s population is exposed.1 Vulnerability assessments presented in Section 4.5 summarize the population exposure for each natural hazard if available.
4.4.1.2 Critical Facilities Inventory
Critical facilities are of particular concern when planning to mitigate hazards. A critical facility is a structure or other improvement that, because of its function, size, service area, or uniqueness, has the potential to cause disruption of vital socioeconomic activities if it is destroyed, damaged, or functionally impaired.
Critical facilities inventory data was developed from a combination of datasets, including from city, special purpose district, state, federal, and private industry. A critical infrastructure spatial database was developed to translate critical facilities information into georeferenced2 points and lifelines.
Critical facility points include police stations, fire stations, hospitals, elder care facilities, daycare facilities, buildings containing hazardous materials (HAZMAT), schools, transportation infrastructure, utilities, and government buildings. Lifelines include communication, electric power, liquid fuel, natural gas, and transportation routes. A current representation of the critical facility points and lifelines are provided in Figure 4-11. Some critical facility information may have been omitted from this document due to national security purposes.
Critical facilities and transportation and lifeline data came from a collection of sources, including but not limited to the City of Napa, California Department of Social Services (CDSS), California Energy Commission (CEC), Federal Communications Commission (FCC), Hazus, U.S. Army Corps of Engineers (USACE), FEMA, and National Park Service (NPS). All data sources have a level of accuracy acceptable for planning purposes. Due to the sensitivity of this information, a detailed list of facilities is not provided. The list is on file with each planning partner. The risk assessment for each hazard qualitatively discusses critical facilities with regard to that hazard.
1 Population estimates were derived from 2013-2017 Census American Community Survey 5-Year (ACS) information. 2 To georeference something means to define its existence in physical space. That is, establishing its location in terms of map projections or coordinate systems. The term is used both when establishing the relation between raster or vector images and coordinates, and when determining the spatial location of other geographical features. 1-26-2022 Submittal EXHIBIT APage 84 of 416
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4.4.1.3 Parcel Value Inventory
The County of Napa Assessor’s data is essential to developing parcel values exposed to each hazard with a spatial footprint and includes the current fair market value of at-risk assets. The City of Napa Parcel Value Inventory is summarized in Table 4-9. This table only includes parcels that are located in the City of Napa. The Parcel Value Inventory includes the market value, 3 content replacement value, and total assessed value (“total value”), and each hazard profile outlines predicted impacts to this inventory for each hazard’s geographic extent. These elements are called out in the table because, in the event of a disaster, the value of the infrastructure or improvements to the land is usually the focus of concern. Generally, the land is not a total loss, and structures can be rebuilt or contents replaced. “Total market value” as presented in this plan reflect Napa County Assessor data including fair market value where available. If no fair market value was available for a given property, the value reflects the assessed improvement value.
“Total content value” was calculated based on the assessor's use codes, translated to occupancy-based multipliers. Each occupancy class prescribes a specific content cost multiplier used to calculate the content cost values shown in the summary and in the hazard profiles in Section 4.5. Occupancy-based content cost multipliers used in this plan reflect those found in the FEMA Hazus-MH 4.2 technical manuals.
Table 4-9: City of Napa Parcel Counts and Value
Total Parcels Total Replacement Value ($) Total Content Value ($) Total Value ($) City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Total replacement value as calculated by pre-determined $300/sqft replacement value. Where building area was undescribed, assessed building values were used. Content value calculated using content multipliers per Hazus occupancy classes per county land use designation. Total value is the sum of total replacement value and total content value. Improved Parcels Only. 3 Market Value includes a long-term asset which indicates the cost of the constructed improvements to land, such as buildings, driveways, walkways, lighting, and parking lots.
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Figure 4-11: City of Napa Critical Facilities
4.4.2 Hazard Exposure and Damage Estimation
The population and inventory information are used to generate specific exposure and damage estimations based on the severity of specific hazard events. The hazards in the City of Napa which have known geographic extents and corresponding spatial information, and thus have exposure and damage estimations, are:
▪ Dam Failure
▪ Climate Change (Sea-Level Rise)
▪ Earthquake (both scenario-based and liquefaction)
▪ Flooding
▪ Wildfire
Population and Asset Exposure
“Exposure” of assets and population refers to the total counts of parcels, people, facilities, and assets within the planning area in which a hazard event may occur. A natural hazards overlay was developed to reflect the combination of many known natural hazard spatial footprints. The spatial overlay method enables summarization of building values, parcel counts, population exposure, and critical facility exposure within a hazard’s geographic extents. Figure 4-12 illustrates hypothetical flooding exposure. Exposure numbers were generated using City of Napa Assessor data, address point, and parcel data for replacement and content cost estimates.
Figure 4-12: Hazard Exposure Explanation Graphic
Damage Estimation
For flood and earthquake, detailed damage estimations were conducted through FEMA’s Hazus software.
Hazus is a nationally applicable, standardized methodology that contains models for estimating potential losses from earthquakes, floods, and hurricanes. Hazus uses Geographic Information Systems (GIS) technology to estimate the physical, economic, and social impacts of disasters. The estimated damage and 1-26-2022 Submittal EXHIBIT APage 87 of 416
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losses provided by the Hazus Software is based upon chosen severity of events and provides the ability to understand possible widescale damage to buildings and facilities.
In the hypothetical geography shown in Figure 4-13, even though both structures are exposed to flooding, it is expected that the structure with a first-floor height below the depth of flooding will receive significantly more damage than the structure with a first-floor height above the expected water depth. For a more detailed explanation of risk assessment methods, see Appendix A.
At-risk populations, critical infrastructure, improved parcels, and loss results for each hazard category are provided in bar chart summary tables in Section 4.5 to evaluate the percentage of assets exposed to different types of hazards. The side-by-side comparison allows the planning committee to evaluate the impacts of potential hazards to prioritize hazard mitigation energy and resources.
Figure 4-13: Hazus Damage Estimation Example
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4.5 Vulnerability to Specific Hazards
This section introduces prevalent hazards within the City of Napa and analyzes how each may affect populations, property, and critical facilities within the City’s jurisdiction. Importantly, the hazard mitigation strategy presented in Section 5 is informed by, and responds to, the particular vulnerabilities outlined in this section. The mitigation strategy provides prescriptions or actions to achieve the greatest reduction of vulnerability based on this section, which results in saved lives, reduced injuries, reduced property damage, and protection for the environment in the event of a natural hazard. Methods for calculating exposure and loss estimates are described in Section 4.3 and Appendix A.
This section provides quantifiable exposures to people and property and damage and loss estimates for the city for the below prioritized hazards.
Dam Failure
SECTION 4.5.1
Earthquake
SECTION 4.5.4
Extreme Weather
SECTION 4.5.7
Drought
SECTION 4.5.2
Pandemic
SECTION 4.5.5
Wildfire
SECTION 4.5.8
Climate Change
SECTION 4.5.3
Flood
SECTION 4.5.6
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4.5.1 Dam Failure Hazard Profile
Dam failures in the United States typically occur in one of four ways:
▪ Overtopping of the primary dam structure, which accounts for 34 percent of all dam failures, can occur due to inadequate spillway design, settlement of the dam crest, blockage of spillways, and other factors. ▪ Foundation defects due to differential settlement, slides, slope instability, uplift pressures, and foundation seepage can also cause dam failure. These account for 30 percent of all dam failures. ▪ Failure due to piping and seepage accounts for 20 percent of all failures. These are caused by internal erosion due to piping and seepage, erosion along hydraulic structures such as spillways, erosion due to animal burrows, and cracks in the dam structure. ▪ Failure due to problems with conduits and valves, typically caused by the piping of embankment material into conduits through joints or cracks, constitutes 10 percent of all failures. (Federal Emergency Management Agency, 2019)
Many dam failures in the United States have been secondary results of other disasters, such as earthquakes, landslides, extreme storms, excessive snowmelt, equipment malfunction, structural damage, foundation failures, and sabotage. Poor construction, lack of maintenance and repair, and deficient operational procedures are preventable or correctable by a program of regular inspections. Terrorism and vandalism are serious concerns that all operators of public facilities must plan for; these threats are under continuous review by public safety agencies. (Id.)
Lake Hennessey
Lake Hennessey, which stores 31,000 acre-feet of water and is a reservoir created by the construction of Conn Creek Dam, is the City of Napa’s principal water supply storage. Conn Creek Dam is of earth fill construction and has a concrete spillway that empties into Conn Creek. The crest height of the dam is 125 feet. The greatest risk for dam failure would be a seismic event. (City of Napa, 2015) Milliken Reservoir
The Milliken Reservoir empties into Milliken Creek. The crest height of Milliken Dam is 110 feet and the reservoir stores 2,000 acre-feet of water at the crest height. In 2008, the dam was modified in order to reduce the elevation 16 feet below the dam crest, and the dam has subsequently been deemed safe to withstand a maximum credible earthquake at the reduced elevation level. (Id.) Rector Reservoir
Rector Reservoir is contained by an earth fill dam and empties into Rector Creek. The crest height of the Rector Creek Dam is 162 feet and the reservoir stores 4,400 acre-feet of water. Because the reservoir is owned by the state, the city is not responsible for the dam's safety. (Id.) 1-26-2022 Submittal EXHIBIT APage 91 of 416
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4.5.1.1 Plans, Policies, and Regulatory Environment
1972 National Dam Safety Act
The potential for catastrophic flooding due to dam failures led to the passage of the 1972 National Dam Safety Act, Pub. Law No. 92-367. The National Dam Safety Program requires a periodic engineering analysis of every major dam in the country. The goal of this FEMA-monitored effort is to identify and mitigate the risk of dam failure so as to protect lives and property.
FERC Dam Safety Program
The Federal Energy Regulatory Commission (FERC) has the largest dam safety program in the United States. FERC cooperates with a large number of federal and state agencies to ensure and promote dam safety, including, more recently, the Department of Homeland Security. There are 3,036 dams that are part of regulated hydroelectric projects in the FERC program. Two-thirds of these are more than 50 years old. (Federal Energy Regulatory Commission, 2011) As dams age, concern about their safety and integrity grows, so oversight and regular inspection are important. FERC staff inspects hydroelectric projects on an unscheduled basis to investigate the following:
▪ Potential dam safety problems;
▪ Complaints about constructing and operating a project; ▪ Safety concerns related to natural disasters; and
▪ Issues concerning compliance with the terms and conditions of a license.
Every five years, an independent consulting engineer, approved by the FERC, must inspect and evaluate projects with dams higher than 10 meters (32.8 feet), or with a total storage capacity of more than 2,000 acre-feet. (Id.)
FERC staff monitors and evaluates seismic research in geographic areas where there are concerns about seismic activity. This information is applied in investigating and performing structural analyses of hydroelectric projects in these areas. FERC staff also evaluates the effects of potential and actual large floods on the safety of dams. During and following floods, FERC staff visits dams and licensed projects, determines the extent of damage, if any, and directs any necessary studies or remedial measures the licensee must undertake. The FERC publication Engineering Guidelines for the Evaluation of Hydropower Projects guides the FERC engineering staff and licensees in evaluating dam safety. The publication is frequently revised to reflect current information and methodologies.
The FERC requires licensees to prepare emergency action plans and conduct training sessions on how to develop and test these plans. The plans outline an early warning system if there is an actual or potential sudden release of water from a dam due to failure. The plans include operational procedures that may be used, such as reducing reservoir levels and reducing downstream flows, as well as procedures for notifying affected residents and agencies responsible for emergency management. These plans are frequently updated and tested to ensure that everyone knows what to do in emergency situations. (Id.) 1-26-2022 Submittal EXHIBIT APage 92 of 416
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U.S. Army Corps of Engineers Dam Safety Program
The U.S. Army Corps of Engineers (“the Corps”) is responsible for safety inspections of some federal and non-federal dams in the United States that meet the size and storage limitations specified in the National Dam Safety Act. The Corps has inventoried such dams and surveyed each state and federal agency’s capabilities, practices, and regulations regarding design, construction, operation, and maintenance of the dams. The Corps develops guidelines for inspection and evaluation of dam safety. (United States Army Corps of Engineers, n.d.)
California Division of Safety of Dams
California’s Division of Safety of Dams (DSOD), a division of the California Department of Water Resources (DWR), monitors the dam safety program at the state level. When a new dam is proposed, division staff inspects the site. DSOD reviews dam applications and building plans to ensure that the dam is designed to meet minimum requirements and that the design is appropriate for known geologic conditions. It also inspects construction to ensure the work is done in accordance with the approved plans. DSOD inspects constructed dams on an annual basis to ensure they are performing as intended and not developing problems. Roughly a third of these inspections include in-depth instrumentation reviews. DSOD periodically reviews the stability of dams and their major appurtenances in light of improved design approaches and requirements, as well as new findings regarding earthquake hazards and hydrologic estimates in California. (DWR, 2019)
Senate Bill 92: Dam Safety
Senate Bill 92 (2017) provides new requirements focused on dam safety. Specifically, it requires dam owners to submit inundation maps to the Department of Water Resources. After they have been approved, the dam owner must then submit an emergency action plan (EAP) to Cal OES. These need to be approved by Cal OES and resubmitted every 10 years. (Cal OES, 2020) City of Napa General Plan
The City of Napa 2015 General Plan includes a number of goals and policies in its Health and Safety Element to mitigate the effects of dam failure. These direct the city to maintain a program for reservoir dam safety review, and they direct the city to request that the state ensure minimal risk from the Rector Reservoir dam by maintaining the dam in a safe condition. The City of Napa is currently updating its General Plan and will integrate dam failure safety policies and programs as part of the update. 1-26-2022 Submittal EXHIBIT APage 93 of 416
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4.5.1.2 Past Events
No dams have failed in Napa County to date. As the risk assessment for the City of Napa illustrates, the chances of a dam failure are low, but the consequences of such are severe.
The most memorable recent event
concerning dam failure in California
was the 2017 collapse of a spillway
on the Oroville Dam in Butte County.
The Oroville Dam is the largest
facility within the State Water
Project in California; the dam stores
3.5 million acre-feet of water and
serves as important flood control for
the Feather River. In 2017, after
substantial runoff from the Sierra
Nevadas, Lake Oroville was full and
the spillway was opened to release
extra water downstream.
“Spillways” are dam safety features
that allow water to overtop the dam
if the reservoir fills too quickly. Spillway overflow events, often referred to as “design failures,” result in increased discharges downstream and increased flooding potential.
The force of the release at Oroville gouged a large crater in the concrete spillway and required the California Department of Water Resources (DWR) to halt water releases via that conduit. See Figure 4-14.
The high lake level then created fear that erosion would compromise the integrity of the auxiliary spillway and flood the City of Oroville and surrounding communities. Thousands were evacuated and runoff eventually receded without further issue. Ultimately, an independent analysis concluded that poor design and construction and inadequate state oversight contributed to the collapse of the concrete spillway. (Water Education Foundation, 2020)
The Oroville Dam spillway failure triggered an inspection of 93 dam spillways across California through the new Spillway Re-evaluation Program, including four in Napa County: Conn Creek, Bell Canyon, Lake Curry, and Rector Creek dams (DWR, 2019)
Figure 4-14: Oroville Dam Spillway after 2017 Failure
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4.5.1.3 Location
According to the California Department of Water Resources (DWR) Division of Safety of Dams (DSOD) and USACE National Inventory of Dams (NID), there are seven dams near the City of Napa which would impact the city in the event of a failure, shown in Table 4-11. Figure 4-15 shows Cal OES and DSOD inundation zones for the dams near the City of Napa. Areas most threatened by dam inundation are those in the northern portion of the city.
Dams listed below are classified by FEMA according to their hazard potential. Table 4-10 explains the classifications of Low, Significant, and High. DSOD includes a fourth category of “Extremely High.” Table 4-11 then lists dams with potential impacts to the City of Napa, including their hazard classification that corresponds with Table 4-10.
Table 4-10: FEMA Hazard Potential Classification
Hazard Potential Classification Loss of Human Life Economic, Environmental, Lifeline Losses Low None expected Low and generally limited to owner
Significant None expected Yes
High Probable. One or more expected Yes (but not necessary for this classification) Extremely High One or more and inundating an
area of 1,000+ population
Inundation of facilities/infrastructure, posing
significant threat to public safety determined
case-by-case by DSOD
Source: Federal Guidelines for Dam Safety- Hazard Potential Classification Systems for Dams, April 2004, DSOD Jurisdictional Dams Table 4-11: Dams with Potential Impacts to the City of Napa NIDID County Dam Name Owner Name Year Completed Hazard Category CA00003 Napa Camille, Lake Napa State Hospital 1880 S
CA00004 Napa Marie, Lake Napa State Hospital 1908 H
CA00011 Napa Rector Creek* California Department of
Veteran Affairs
1946 H
CA00102 Napa Milliken* City of Napa 1924 H
CA00104 Napa Conn Creek* City of Napa 1946 H
CA00149 Napa Bell Canyon City of Saint Helena 1959 H
CA00980 Napa Cynthia, Lake Krupp Brothers Vineyard 1955 S Hazard Definitions: L – Low; S – Significant; H – High; H+ – Extremely High *- Emergency Action Plan developed and DWR data integrated into exposure analysis Source: DWR Jurisdictional Dams & USACE National Inventory of Dams 1-26-2022 Submittal EXHIBIT APage 95 of 416
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Figure 4-15: Dam Inundation Exposure
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4.5.1.4 Severity and Extent
Dam failure can be catastrophic to all life and property downstream. Table 4-11 lists dams near the City of Napa which would impact the city in the event of a dam failure. The same table shows the hazard classification as designated by FEMA and DSOD.
This hazard potential classification system categorizes dams based on the probable loss of human life and the impacts on economic, environmental, and lifeline interests. Improbable loss of life exists where persons are only temporarily in the potential inundation area. For instance, this hazard potential classification system does not contemplate the improbable loss of life of the occasional recreational users of the river and downstream lands, passers-by, or non-overnight outdoor users of downstream lands. In any classification system, all possibilities cannot be defined. High usage areas of any type should be considered appropriately. Judgment and common sense must ultimately be a part of any decision on classification. Further, no allowances for evacuation or other emergency actions by the population should be considered because emergency procedures should not be a substitute for appropriate design, construction, and maintenance of dam structures.
While there are no extremely high hazard dams listed in Napa County, there are five high hazard dams which would potentially impact the city in the event of a failure.
4.5.1.5 Frequency and Probability of Future Occurrences The probability of any type of dam failure is low in today’s regulatory and dam safety oversight environment. Dam failure events usually coincide with events such as earthquakes, landslides, and excessive rainfall and snowmelt.
4.5.1.6 Warning Time
Warning time for dam failure depends on the cause of failure. In the event of extreme precipitation or excessive snowmelt, evacuations can be planned with sufficient time. Conversely, in the event of a structural failure due to earthquake, there may be little to no warning time. A dam’s structural type also affects warning time. Earthen dams do not tend to fail instantaneously. Once a breach is initiated, discharging water erodes the breach until the reservoir water is depleted, or the breach resists further erosion. Concrete gravity dams also tend to have an initial partial breach. The time of breach formation ranges from a few minutes to a few hours.
Developing Emergency Action Plans (EAPs) for all high and significant hazard potential dams for the City of Napa is critical to reducing the risks of loss of life and property damage from dam failures. The EAP contains procedures and information to assist the dam owner in issuing early warning and notification messages to emergency management authorities. The EAP also contains inundation maps to identify the areas subject to flooding in the unlikely event of dam failure. This hazard mitigation plan utilizes California Division of Water Resource (DWR) data from EAPs for the Milliken, Rector Creek, and Conn Creek Dams. 1-26-2022 Submittal EXHIBIT APage 97 of 416
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EAPs are critical in identifying areas downstream from dams requiring warning and evacuation in the event of dam failure. Documented cases have demonstrated that warning and evacuation time for EAPs can dramatically influence the loss of life. Loss of life can vary from 0.02 percent of the persons at risk when the warning time is 90 minutes up to 50 percent when warning time less than 15 minutes. (Graham, 1988) One USGS report states that the average number of fatalities per dam failure is 19 times greater when there is little to no warning. (U.S. Geological Survey, 1985) Dam breach inundation studies usually assume one of two failure scenarios:
▪ Flows from a dam failure during “fair weather” or “sunny day” conditions with the reservoir at the normal pool level and receiving normal inflow (usually insignificant). A fair weather failure is generally considered to have the most potential for loss of human life, primarily due to the element of surprise.
▪ Flows from a dam failure during flood conditions or the inflow design flood. Failure during flood conditions is considered to show the upper limit of inundation and to have less potential for loss of human life because the downstream population is on alert. The flood conditions scenario is more expensive to analyze due to the additional cost for necessary watershed and spillway studies.
Inundation mapping shows a continuous line of inundation identifying the area potentially at risk in the event of dam failure. It starts at the dam and continues downstream to a point where the breach flood no longer poses a risk to life and property damage, such as a large river or reservoir with the capacity of storing the floodwaters. The need to consider the “domino effect” should be made on a caseby-case basis if the assumed failure of a dam would cause the failure of any downstream dams.
4.5.1.7 Secondary Hazards
Dam failure can cause severe downstream flooding, depending on the magnitude of the failure. Other potential secondary hazards of dam failure are landslides around the reservoir perimeter, bank erosion on rivers, and destruction of downstream habitat.
4.5.1.8 Dam Failure Vulnerability Analysis
Dam inundation zones as provided by the California Division of Water Resources (DWR) were used in conjunction with the inventory listed in Table 4-11 to identify at-risk populations and loss estimations for dam failure.
Note that DWR dam inundation data is used for the damage estimation, exposure analysis, and mapping for Conn Creek, Rector Creek, and Milliken Dams. Legacy Cal OES data was used for the exposure analysis and mapping in Figure 4-15 and Figure 4-16 where DWR data was not available or included. Legacy Cal OES-sourced dams include Bell Canyon, Lake Camille, Lake Cynthia, and Lake Marie. The DWR inundation data is more recently developed (since SB 92 passed in 2017) and more detailed than Cal OES inundation zones. The DWR data also includes only those dams rated extremely high, high, or significant risk. DWR data is also the only data set generally available with a depth grid, as defined by emergency action plan 1-26-2022 Submittal EXHIBIT APage 98 of 416
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(EAP) submittals from dam owners, as required for Hazus. Therefore, while the population exposure utilizes the Cal OES data set, the damage estimation through Hazus utilizes the narrower DWR data set.
Exposure Analysis
Population
The primary danger associated with dam failure is high-velocity flooding downstream of the dam and limited warning times for evacuation. Vulnerability varies by community and depends on the particular dam profile and the nature and extent of the failure. Vulnerable populations are present directly below the dam and may include persons incapable of escaping the area within the allowable time frame. This population includes the elderly and young, who may be unable to self-evacuate from the inundation area.
Vulnerable populations also include those who would not have adequate warning from a television or radio emergency warning system, have not registered with reverse 911, or do not have cell phones that can receive amber alerts. The potential for loss of life is affected by the capacity and number of evacuation routes available to populations living in areas of potential inundation. The entire population in a dam failure inundation zone is exposed to the risk of a dam failure. The estimated population exposed to dam inundation is summarized in Figure 4-16 and Table 4-12. 1-26-2022 Submittal EXHIBIT APage 99 of 416
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Figure 4-16: Dam Failure Vulnerability Snapshot Map
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Table 4-12: Population Exposure to Dam Failure
Total Population
City of Napa 79,722
Dam Inundation Zone Population Count % of Total
Bell Canyon - 0.00%
Conn Creek (DWR) 11,668 14.64%
Lake Camille 2,159 2.71%
Lake Cynthia - 0.00%
Lake Marie 2,601 3.26%
Milliken (DWR) 1,222 1.53%
Rector Creek (DWR) 1,640 2.06%
Total* 13,742 17.24%
*Total population is not equal to sum of all dam inundation zones due to dissolved overlapping inundation areas.
Figure 4-17: Population Exposure to Dam Inundation by Zone -
11,668
2,159
-
2,601
1,222 1,640
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
Bell Canyon Conn Creek
(DWR)
Lake Camille Lake Cynthia Lake Marie Milliken (DWR) Rector Creek (DWR)
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Property
Vulnerable properties are those closest to the dam inundation area. These properties would experience the largest, most destructive surge of water. Low-lying areas where water would collect are also vulnerable.
Transportation routes, discussed below, are vulnerable to dam inundation and have the potential to be eliminated or compromised, creating isolation issues. Utilities, such as overhead power, cable, and phone lines, could also be vulnerable. Loss of these utilities could create additional isolation issues for the inundation areas. Table 4-13 displays parcel values exposed to dam inundation.
Table 4-13: Parcel Values at Risk from Dam Inundation
Total Parcels
Total
Replacement
Value ($)
Total Content
Value ($) Total Value ($)
City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Dam Inundation Zone Parcel Count % of Total
Replacement
Value Exposure
($)
Content Value
Exposure ($) Total Exposure ($) % of Total
Bell Canyon - 0.0% $0 $0 $0 0.0%
Conn Creek (DWR) 5,501 15.3% $1,772,388,590 $1,328,921,234 $3,101,309,823 12.9% Lake Camille 480 1.3% $289,491,113 $243,183,282 $532,674,395 2.2% Lake Cynthia - 0.0% $0 $0 $0 0.0%
Lake Marie 677 1.9% $362,378,002 $297,087,930 $659,465,932 2.7% Milliken (DWR) 27 0.1% $1,965,360 $2,334,228 $4,299,588 0.0% Rector Creek (DWR) 132 0.4% $23,976,117 $18,829,718 $42,805,835 0.2% Dam Inundation Area* 6,144 17.1% $2,031,418,468 $1,526,400,390 $3,557,818,858 14.8% *Totals are not equal to sum of all dam inundation zones due to dissolved overlapping inundation areas.
Critical Facilities and Lifelines
Low-lying areas are vulnerable to dam inundation, especially transportation routes. This includes all roads, railroads, and bridges in the flow path of water, which could be eliminated or compromised in a dam inundation event. The most vulnerable critical facilities are those in poor condition that would have difficulty withstanding a large surge of water. Utilities such as overhead power lines and communication lines could also be vulnerable. Loss of these utilities could create additional compounding issues for emergency management officials attempting to conduct evacuation and response actions. Table 4-14 and Table 4-15 summarizes critical infrastructure exposed to dam failure in the City of Napa. 1-26-2022 Submittal EXHIBIT A Page 102 of 416
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Table 4-14: Critical Infrastructure Points in Dam Inundation Zones Infrastructure
Type
TOTAL
FEATURE
COUNT
Bell
Canyon
Conn
Creek
(DWR)
Lake
Camille
Lake
Cynthia
Lake
Marie
Milliken
(DWR)
Rector
Creek
(DWR)
Essential Facility** 1 - 1 1 - 1 - -
Fire Station 1 - 1 1 - 1 - -
Hospital - - - - - - - -
Police Station - - - - - - - -
High Potential Loss 72 - 69 2 - 4 1 1
Adult Residential Facility 1 - 1 - - - - -
Child Care Center 6 - 5 1 - 1 - -
Church 5 - 5 - - - - -
Communication Tower 4 - 4 - - - - -
Dam - - - - - - - -
Farm Worker Housing - - - - - - - -
Foster Family Agency 1 - 1 - - - - -
Historic Building 23 - 23 - - - - -
Home Care Organization 1 - 1 - - - - -
Library 2 - 2 - - - - -
*Real Property Asset 20 - 20 1 - 1 - -
Residential Child Care - - - - - - - -
Residential Elder Care Facility 1 - 1 - - - - -
School 4 - 3 - - 1 - -
Stream Rain Gauges 4 - 3 - - 1 1 1
Water Treatment Plant - - - - - - - -
Transportation and Lifeline 37 - 35 3 - 4 8 12
Bridge 16 - 15 1 - 2 8 10
Power Plant 1 - 1 - - - - -
Pressure Regulator Station 4 - 4 - - - - 1
Pump Station - - - - - - - -
Sample Station 15 - 14 2 - 2 - 1
Substation 1 - 1 - - - - -
Water Tank - - - - - - - -
Grand Total 110 - 105 6 - 9 9 13
* Real Property Assets are digitized insurance rolls for demonstrating value and ownership. ** Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here. 1-26-2022 Submittal EXHIBIT A Page 103 of 416
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Table 4-15: Miles of Critical Infrastructure (Linear) in Dam Inundation Zones Infrastructure Type
(linear)
TOTAL DAM
EXPOSURE
Bell
Canyon
Conn
Creek
(DWR)
Lake
Camille
Lake
Cynthia
Lake
Marie
Milliken
(DWR)
Rector
Creek
(DWR)
Levee 2.1 - 2.1 - - - 0.3 0.1
Levee Centerline 1.1 - 1.1 0.5 - 0.5 - -
Levee Flood Wall 1.0 - 1.0 - - - 0.0 0.3
NG Pipeline 3.1 - 3.0 0.2 - 0.3 0.5 0.0
Railroad 4.9 - 4.9 0.1 - 0.1 0.2 0.2
Street 46.0 - 41.9 4.0 - 5.4 0.7 5.0
Alley - - - - - - - -
Cul-de-sac 0.1 - 0.1 - - - - -
Driveway 0.4 - 0.4 - - - - -
Interstate - - - - - - - -
Local road 2.1 - 2.0 0.1 - 0.1 0.0 0.1
Local road, major 30.3 - 27.0 2.6 - 3.8 0.2 3.4
Primary highway 0.5 - 0.5 - - - 0.0 -
Ramp 0.1 - 0.1 - - - - -
Road, parking area 1.1 - 1.1 0.5 - 0.5 - 0.1
State/county highway 11.2 - 10.5 0.8 - 1.1 0.5 1.3
Thoroughfare, major 0.1 - 0.1 - - - - -
Traffic circle 0.1 - - 0.1 - 0.1 - -
Electric Transmission Line 4.1 - 4.0 0.2 - 0.3 0.2 0.4
Water Transmission Line* 6.4 - 5.8 0.5 - 0.7 0.6 0.8
Grand Total 68.7 - 63.8 5.5 - 7.2 2.6 6.8
* Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here.
Damage Estimations
Hazus calculates losses to structures from flooding by analyzing the depth of flooding and type of structure. Using historical flood insurance claim data, Hazus estimates the percentage of damage to structures and their contents by applying established damage functions to an inventory. For this analysis, dam inundation depth grids are reported. Damage is indicated by depth and velocity. Return intervals, utilized in the damage estimation for flood, are omitted here due to relevance. This analysis uses data from the Department of Water Resources and has only been conducted for the City of Napa dams for which there are existing inundation studies. Table 4-16 reports damage to parcel and government property loss. 1-26-2022 Submittal EXHIBIT A Page 104 of 416
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Damage Estimation Improved Parcel and Government Property Loss Department of Water Resources data were used to estimate the loss potential to residential properties and government service facilities exposed to dam inundation. Hazus reports the damage potential and loss potential from a given dam failure scenario in four categories: slight damage, moderate damage, extensive damage, and economic loss. Economic loss consists of estimations on the cost of repair and replacement to damaged or destroyed buildings and contents, relocation expenses, and capital-related income, wage, and rental income losses. The results shown in Table 4-16, Table 4-17, and Table 4-18 summarize improved parcel and government property loss for Conn Creek, Milliken, and Rector Creek Dams, respectively.
Table 4-16: Improved Parcel and Government Property Loss Estimations (Conn Creek Dam) Building Type Building Damage
($)
Building
Damage
(% of total loss)
Content Damage
($)
Content
Damage
(% of total loss)
Total Damage ($) Proportion of
Loss (%)
Agriculture $1,160,847 0% $2,198,592 0% $3,359,438 0%
Commercial $141,151,769 12% $443,655,004 39% $584,806,773 52% Education $0 0% $0 0% $0 0%
Emergency $241,146 0% $41,248 0% $282,394 0%
Government $2,730,678 0% $985,639 0% $3,716,317 0%
Industrial $19,330,619 2% $54,671,099 5% $74,001,718 7% Religion $0 0% $0 0% $0 0%
Residential $323,479,194 29% $142,274,205 13% $465,753,400 41% Total $488,094,253 43% $643,825,787 57% $1,131,920,040
Note: Total Inventory Values
1 - Building Replacement Costs = $13,885,314,683
2 - Content Replacement Costs = $10,307,648,380
3 - Total Value = $24,192,963,063
$0 $100,000,000 $200,000,000 $300,000,000 $400,000,000 $500,000,000 Agriculture
Commerci…
Education
Emergency
Governme…
Industrial
Religion
Residential
Content Damage ($) Building Damage ($)
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Figure 4-18: Improved Parcel and Government Property Loss Estimations (Conn Creek Dam) Table 4-17: Improved Parcel and Government Property Loss Estimations (Milliken Dam) Building Type Building
Damage ($)
Building Damage
(% of total loss)
Content
Damage ($)
Content
Damage
(% of total loss)
Total Damage ($) Proportion of
Loss (%)
Agriculture $39,856 6% $176,968 28% $216,824 0%
Commercial $0 0% $0 0% $0 0%
Education $0 0% $0 0% $0 0%
Emergency $0 0% $0 0% $0 0%
Government $0 0% $0 0% $0 0%
Industrial $92,384 15% $235,180 38% $327,564 0%
Religion $0 0% $0 0% $0 0%
Residential $64,838 10% $16,871 3% $81,709 0%
Total $197,078 31% $429,019 69% $626,097
Note: Total Inventory Values
1 - Building Replacement Costs = $13,885,314,683
2 - Content Replacement Costs = $10,307,648,380
3 - Total Value = $24,192,963,063
Figure 4-19: Improved Parcel and Government Property Loss Estimations (Milliken Dam) $0 $50,000 $100,000 $150,000 $200,000 $250,000
Agriculture
Commercial
Education
Emergency
Government
Industrial
Religion
Residential
Content Damage ($) Building Damage ($)
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Table 4-18: Improved Parcel and Government Property Loss Estimations (Rector Creek Dam) Building Type Building Damage
($)
Building Damage
(% of total loss)
Content Damage
($)
Content
Damage
(% of
total
loss)
Total Damage ($) Proportion of
Loss (%)
Agriculture $4,599 0% $23,103 0% $27,702 0%
Commercial $4,358,009 11% $9,723,026 25% $14,081,036 1% Education $0 0% $0 0% $0 0%
Emergency $0 0% $0 0% $0 0%
Government $0 0% $0 0% $0 0%
Industrial $157,193 0% $329,518 1% $486,712 0%
Religion $0 0% $0 0% $0 0%
Residential $17,943,144 46% $6,108,213 16% $24,051,357 2% Total $22,462,947 58% $16,183,860 42% $38,646,807
Note: Total Inventory Values
1 - Building Replacement Costs = $13,885,314,683
2 - Content Replacement Costs = $10,307,648,380
3 - Total Value = $24,192,963,063
$0 $5,000,000 $10,000,000 $15,000,000 $20,000,000
Agriculture
Commercial
Education
Emergency
Government
Industrial
Religion
Residential
Content Damage ($) Building Damage ($)
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Figure 4-20: Improved Parcel and Government Property Loss Estimations (Rector Creek Dam) Damage Estimation for City-Owned Property
Hazus 4.2 was used to estimate the loss potential to city facilities exposed to dam failure in the City of Napa. Hazus reports the damage potential and loss potential from a given dam failure scenario in four categories: slight damage, moderate damage, extensive damage, and economic loss. Economic loss consists of estimations on the cost of repair and replacement to damaged or destroyed buildings and contents, relocation expenses, and capital-related income, wage, and rental income losses.
City insurance data was obtained and formatted for use in Hazus for a detailed damage estimation. This dataset has additional information, including the number of floors, building value, content value, and construction type, that greatly enhances results from the default Hazus database. See Table 4-19 for damage estimation results for Conn Creek. Milliken, and Rector CreekDams do not display damage estimation for city-owned properties; there are no losses calculated for Milliken Dam, and Rector Creek Dam has negligible damages.
Table 4-19: Damage Estimate Insurance Roll Details (Conn Creek Dam) Value Damage Pct. Estimated Losses (USD)
Building/
Site Name Count Structure Content Structure Content Structure Content Total Loss Pct.
of Value
Library 1 $2,602,390 $57,841 13% 77% $348,101 $44,761 $392,861 15% Restroom 1 $127,547 $1 15% 96% $18,590 $1 $18,591 15%
Teen
Center 1 $184,741 $28,169 14% 95% $26,785 $26,757 $53,543 25% Shop 4 $2,585,021 $422,049 18% 100% $437,117 $422,049 $859,166 29% Equipment 2 $139,252 $5,787 18% 100% $24,848 $5,787 $30,635 21% Corp Yard 2 $61,508 $2 18% 100% $11,027 $2 $11,029 18%
Office 2 $1,064,343 $198,682 18% 100% $189,668 $198,682 $388,350 31% Misc 1 $1 $1 19% 100% $0 $1 $1 59%
Lot 2 $890,987 $281,686 17% 100% $133,590 $281,503 $415,093 35% Fire 2 $3,092,769 $359,260 7% 22% $244,904 $45,606 $290,510 8% Parking
Garage 2 $11,379,320 $2 10% 64% $1,163,331 $1 $1,163,332 10% Historic 1 $2,184,260 $1 12% 70% $257,546 $1 $257,546 12% Museum 1 $850,108 $1 13% 78% $114,046 $1 $114,047 13%
Storage 1 $13,303 $1,735 17% 100% $2,270 $1,735 $4,005 27% Grand Total 23 $25,175,550 $1,355,217 15% 86% $2,971,824 $1,026,887 $3,998,711 15% 1-26-2022 Submittal EXHIBIT A Page 108 of 416
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4.5.1.9 Future Trends in Development
Flooding due to a dam failure event is likely to exceed the special flood hazard areas regulated through local floodplain ordinances. The Planning Committee should consider the dam failure hazard when permitting development in mapped dam inundation zones and downstream of high hazard and significant hazard dams in the city. Low hazard dams could become significant or high hazard dams if development occurs below them.
4.5.1.10 Dam Failure Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and dam failure hazard data.
Dam failure hazard problem statements are listed in Table 4-20.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. See Table 5-6 for a full list of mitigation actions and corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-20 and Table 5-6.
Table 4-20: Dam Failure Problem Statements
Problem No.
Hazard
Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-DF-CN-41 Dam
Failure
Impact PRV - Prevention ,
ES - Emergency
Services
Additional planning and preparation
needed to ensure a coordinated response by
local emergency services to a dam failure
event.
ma-DF-CN-15,
ma-DF-CN-52,
ma-AH-CN-0
ps-DF-CN-42 Dam
Failure
Impact PRV - Prevention ,
ES - Emergency
Services
Dam failure planning is not currently
integrated into City or County EOP planning
documents.
ma-DF-CN-52,
ma-AH-CN-0
ps-DF-CN-43 Dam
Failure
Impact PRV - Prevention ,
PPRO - Property
Protection
188 points designated as critical
infrastructure are located in a dam
inundation zone, including: 2 fire stations, 1
police station, 1 power plant, 3 residential
elder care facilities, 1 adult residential
facility, 1 residential child care facility, 5
communication towers, 8 schools
ma-DF-CN-52,
ma-DF-CN-15
ps-DF-CN-44 Dam
Failure
Victim PPRO - Property
Protection , PE&A
- Public
Education &
Awareness , SP -
Structural
Projects
22,643 people live within a dam inundation
zone in City limits.
ma-DF-CN-52,
ma-AH-CN-8,
ma-AH-CN-9
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4.5.2 Drought Hazard Profile
California's water resources have been stressed by periodic drought cycles and in some places overuse, creating the need for unprecedented state and local restrictions in water use. While the duration and severity of drought is always in question, it is certain that California and the City of Napa will continue to be impacted by drought. (California Drought Contingency Plan, 2010) Climate change is expected to increase drought.
Drought has impacted almost every county in California at one time or another, causing more than $2.6 million in damage. Droughts exceeding three years are relatively rare in northern California, the source of much of the state’s water supply. The 1929-1934 drought established the criteria commonly used in designing storage capacity and yield for large northern California reservoirs. The driest single year in California’s measured hydrologic history was 1977. (California Department of Water Resources, 2015) Drought impacts in California are felt first by those most dependent on annual rainfall, including agencies fighting wildfires, ranchers engaged in dryland grazing, rural residents relying on wells in low-yield rock formations, or small water systems lacking a reliable water source. (Id.) Most of California’s precipitation comes from storms moving across the Pacific Ocean. The path followed by the storms is determined by the position of an atmospheric high-pressure belt that normally shifts southward during the winter, allowing low-pressure systems to move into the state. On average, 75 percent of California’s annual precipitation occurs between November and March, with 50 percent occurring between December and February. If a persistent Pacific high-pressure zone takes hold over California midwinter, the water year tends to be dry. (Western Regional Climate Center, 2020) A typical water year produces about 100 inches of rainfall over the North Coast and 50 inches of precipitation (a combination of rain and snow) over the Northern Sierra, compared to 18 inches in the Sacramento area and 15 inches in the Los Angeles area. In extremely dry years, these annual totals can fall to as little as one half or one third of these amounts. (Id.) The Napa River, its tributaries, and the underlying groundwater aquifer are the major water resources in the Napa area. The city relies on surface water for its municipal water supply. Surface water supplies throughout the city are used for domestic, commercial, industrial, agricultural, and fire protection needs.
Groundwater in the city planning region is sourced from the Napa Valley Subbasin. The Napa Valley Subbasin lies within Napa County, and partially overlaps with the City of Napa, as well as neighboring cities. Napa County has been subdivided into groundwater subareas based on watershed boundaries, groundwater basins, and the county’s environmental resource planning areas. This was done in order to encourage better local planning, understanding, and studies. The Subbasin includes four subareas:
Calistoga, St. Helena, Yountville, and Napa. (Napa County, 2016) 1-26-2022 Submittal EXHIBIT A Page 111 of 416
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Geologically, the Napa Valley Subbasin is an active zone of complex tectonic deformation and downwarping, which is generally associated with the San Andreas Fault. A majority of the faults are northwest trending, and this region of the Coast Range is known for its low mountainous ridges separated by intervening stream valleys. The geologic setting of the subbasin provides a basis for understanding the physical properties of the aquifer system and the structural properties that influence groundwater flow. (Id.)
4.5.2.1 Plans, Policies, and Regulatory Environment
California Sustainable Groundwater Management Act
On September 16, 2014, Governor Brown signed into law a package of bills (SB1168, AB1739 and SB1319) collectively called the Sustainable Groundwater Management Act (SGMA). SGMA requires governments and water agencies of high and medium priority basins to halt overdraft and bring groundwater basins into balanced levels of pumping and recharge. Under SGMA, these basins should reach sustainability within 20 years of implementing their sustainability plans. For critically over-drafted basins, that date will be 2040. For the remaining high and medium priority basins, 2042 is the deadline.
Statewide Emergency Water Conservation Regulations
In 2016, the State Water Resources Control Board adjusted emergency water conservation regulations in recognition of the differing water supply conditions and ongoing drought across the state to comply with an Executive Order from the California Governor declaring a drought emergency. Executive Order B-37-16 (“Making Water Conservation a California Way of Life”) updates temporary emergency water restrictions and transitions to permanent, long-term improvements in water use by:
▪ Providing for wiser water use;
▪ Eliminating water waste;
▪ Strengthening local drought resilience; and
▪ Improving agricultural water use efficiency and drought planning.
In April of 2017, a new Executive Order lifted the drought emergency but retained many of the conservation requirements. Most regulations are still in effect with the exception of water supply “stress test” requirements and mandatory conservation standards for urban water suppliers. The temporary restrictions established a baseline of the types of benefits that are possible from water conservation requirements. The Governor can reinstate mandatory water conservation measures and may choose to do so for the 2021-2022 water year, which starts October 1, 2021, due to the severity of the drought at the time of this update.
California Water Plan
The California Water Plan presents strategic plan elements for current water conditions, challenges, and activities, including a vision, mission, goals, guiding principles, and recommendations. The plan includes future uncertainties and climate change impacts, scenarios for 2050, and a roadmap for improving data 1-26-2022 Submittal EXHIBIT A Page 112 of 416
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and analytical tools needed for integrated water management and sustainability. The California Water Plan was updated most recently in 2018. See: https://water.ca.gov/Programs/California-Water-Plan.
Water Conservation Act of 2009
The Water Conservation Act of 2009 (Senate Bill X7-7) mandates that all water suppliers improve their water use efficiency. The Bill includes 18 actions which the Department of Water Resources is responsible for implementing or enforcing. Some of the projects are meant to increase public engagement, some require rulemaking, and some require reporting.
Napa Valley Drought Contingency Plan
The Napa Valley Drought Contingency Plan is being developed by a task force of local water managers. It includes a means of drought monitoring, a vulnerability assessment, mitigation actions, response actions, an operational and administrative framework, and a plan update process.
City of Napa General Plan
The City of Napa 2015 General Plan includes a number of goals, policies, and implementation programs in its Community Services Element to mitigate the effects of drought. These provisions are designed to anticipate water shortages, and ensure adequate, reliable, and safe water supplies. The City is currently updating its General Plan and will integrate drought protection and water conservation policies and programs as part of the update.
City of Napa Municipal Code
The Napa Municipal Code includes a host of water conservation and efficiency measures. Some include:
Permanent water conservation regulations at § 13.09.010 require new development to completely offset that new development’s water requirements by implementing low-flow toilets (no more than
1.6 gallons per flush) in existing residences or other facilities with higher flush toilets. In the alternative, an “in-lieu retrofit fee” may be offered at the discretion of the water general manager.
Temporary water conservation measures include moderate water shortage regulations at § 13.10.
Moderate measures include limitations on the use of water to irrigate landscaping, including days of the week and time of day limitations. Other limitations include operators of eating and drinking establishments not serving water unless requested and limitations on pool water usage.
Severe water shortage regulations at § 13.12 include specific water use allocations calculated to achieve an overall 20 percent reduction in water usage from pre-drought consumption levels. The city’s 50 largest water users must submit a water conservation plan to implement all reasonably feasible water conservation measures. Finally, rates are adjusted to meet budgetary obligations of the water division and steep fines are assessed for excess water usage.
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High performance building regulations in § 15.04 include some based on CALGreen and some more stringent amendments. More stringent amendments include kitchen faucet flow rate and Energy Star dishwasher and clothes washer requirements. The City of Napa mandates an additional 12 percent indoor savings (Tier 1) beyond the standard 2019 CALGreen fixture flow rates for new nonresidential development. Non-Residential projects must also meet additional measures for specialized appliances, including commercial clothes washers, dishwashers, ice makers, and food steamers. To minimize leaks, projects of all types are subject to a maximum static service pressure of 60 psi. (Napa City Website, 2021)
4.5.2.2 Past Events
California experienced massive changes over the course of the twentieth century, as evidenced by dramatic population increases and land use conversion. (California Department of Water Resources, 2015) The California Department of Water Resources has state hydrologic data back to the early 1900s. Notable historic statewide droughts include the multi-year events of 1929 to 1934, 1976 to 1977, 2007 to 2009, and, most recently, 2012 to 2016. (California Department of Water Resources, 2020).
The state and Napa County are
currently in drought at the time of
this update. Prior to 2021, the most
recent major drought in California
spanned 2012 to 2016. California
State Governor Jerry
Brown declared a drought state of
emergency on January 17, 2014. In
the emergency declaration,
Governor Brown directed state
officials 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 a greatly expanded water conservation public awareness campaign. Figure 4-21 shows a drought-impacted irrigation reservoir in Napa Valley in 2014. On April 17, 2017, Brown issued Executive Order B-40-17, officially ending the drought state of emergency in all California counties except Fresno, Kings, Tulare, and Tuolumne. As is the case with some of California’s other iconic droughts, the 2012 to 2016 drought came to an abrupt end after a significantly wet year in 2017.
Figure 4-21: Drought-Lowered Irrigation Reservoir in Napa Valley in 2014
Photo by Howard Yue, Napa Valley Register
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The National Drought Monitor provides drought data and maps nationally and on a localized, watershed scale. The National Drought Monitor is the product of 11 agencies, including the NDMC, NOAA, and USDA, and is available at http://droughtmonitor.unl.edu/. The National Drought Monitor categorizes the level of drought from D0 through D4, with D4 being the highest “exceptional drought.” Table 4-21 depicts drought classifications and impacts from the level of drought occurrence in California. As of November 2021, during this plan update, Napa County including the City of Napa is classified as experiencing exceptional drought, the highest category.
Figure 4-22 shows a time series of the level of drought in the San Pablo Bay from 2000 to 2021 according to the National Drought Monitor. The National Drought Monitor also classifies drought on a watershed scale according to hydrologic units established by the U.S. Geological Survey.
Drought is one of the few hazards with the potential to impact the entire population of the City of Napa directly or indirectly through water restrictions, higher water and food prices, reduced air or water quality, or restricted access to recreational areas. No portion of the city is immune from drought conditions. Lack of winter snowfall in the mountains can eventually lead to agricultural impacts due to decreased stream flows. Droughts of just a few weeks during critical periods of plant development can have disastrous effects on agriculture production. Reduced reservoir storage from decreased runoff in the mountains can lead to water shortages. Droughts that occur in populated areas may not have direct effects on the residents but may increase the threat of wildfire in the wildland-urban interface.
4.5.2.3 Location
Drought is one of the few hazards with the potential to impact the entire population of the City of Napa directly or indirectly through water restrictions, higher water and food prices, reduced air and water quality, or restricted access to recreational areas. No portion of the city is immune from drought conditions.
Lack of winter snowfall in the mountains can eventually lead to agricultural impacts due to decreased stream flows. Reduced base flows may introduce additional challenges for communities that depend on direct drinking water supplies from rivers and tributaries. Droughts of just a few weeks during critical periods of plant development can have disastrous effects on agriculture production. Reduced reservoir storage from decreased runoff in the mountains can lead to water shortages. Droughts that occur in populated areas may not have direct effects on the residents but may increase the threat of wildfire in wildland urban interface areas.
4.5.2.4 Frequency and Probability of Future Occurrences Currently, there is no data on the probability of drought akin to data for predicting earthquakes or flood probability. Empirical studies conducted over the past century have shown that meteorological drought is never the result of a single cause. It is the result of many causes, often synergistic in nature. These include 1-26-2022 Submittal EXHIBIT A Page 115 of 416
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global weather patterns that produce persistent, upper-level high-pressure systems along the West Coast with warm, dry air, resulting in less precipitation.
According to the results of the risk factor exercises for the participating jurisdictions, the probability of drought occurring in the City of Napa is highly likely (100 percent annual probability). Figure 4-22 provides a time series from the National Drought Monitor that shows the City of Napa has been in some form of drought for much of the period from 2000 to 2021.
Table 4-21: Drought Classifications and Impacts for California Category Description Possible Impacts
D0
Abnormally
Dry
▪ Soil is dry; irrigation deliver begins early
▪ Dryland crop germination is stunted
▪ Active fire season begins
D1
Moderate
Drought
▪ Dryland pasture growth is stunted; producers give supplemental feed to cattle ▪ Landscaping and gardens need irrigation earlier; wildlife patters begin to change ▪ Stock ponds and creeks are lower than usual
D2
Severe
Drought
▪ Producers increase water efficiency methods and drought-resistant crops ▪ Fire season is longer, with high burn intensity, dry fuels, and large spatial extent ▪ Trees are stressed; wildlife diseases increase
▪ Water temperatures increase; programs to divert water to protect fish begin ▪ River flows decrease; reservoir levels are low and banks are exposed D3
Extreme
Drought
▪ Livestock need expensive supplemental feed; little pasture remains ▪ Federal water not adequate to meet irrigation contracts, extracting supplemental groundwater is expensive
▪ Dairy operations close
▪ Fire season lasts year-round; fires occur in typically wet parts of the state; burn bans are implemented
▪ Orchard removal and will drilling company business increase; panning for gold increases ▪ Low water levels impede fish migration and cause lower survival rates ▪ Wildlife encroach on developed areas; little native food and water is available for bears, which hibernate less
▪ Water sanitation is a concern, reservoir levels drop significantly, surface water is nearly dry, flows are very low; water theft occurs
▪ Well and aquifer levels decrease; homeowners drill new wells D4
Exceptional
Drought
▪ Fields are left fallow; orchards are removed; vegetable yields are low; honey harvest is small; agricultural unemployment is high, food aid is needed
▪ Fire season is very costly; number of fires and areas burned are extensive ▪ Many recreational activities are affected
▪ Fish rescue and relocation begins; pine beetle infestation occurs; forest mortality is high; wetlands dry up; survival of native plants and animals is low; fewer wildflowers bloom; wildlife death is widespread; algae blooms appear
▪ Poor air quality affects health; greenhouse gas emissions increase as hydropower production decreases; West Nile outbreaks rise
▪ Water shortages are widespread; surface water is depleted; federal irrigation water deliveries are curtailed; water prices are extremely high; wells are dry, more and deeper wells are drilled; water quality is poor
Source: Adapted from U.S. Drought Monitor Drought Classifications and Impacts (https://droughtmonitor.unl.edu/Data/StateImpacts.aspx) 1-26-2022 Submittal EXHIBIT A Page 116 of 416
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Figure 4-22: San Pablo Bay Drought Severity Timeline 2000-2021
4.5.2.5 Severity and Extent
The severity and extent of a drought depends on the degree of moisture deficiency, the duration, and the size and location of the affected area. The longer the duration of the drought and the larger the area impacted, the more severe the potential impacts. Droughts are not usually associated with direct impacts on people or property, but they can have significant impacts on agriculture, which can impact people indirectly.
Unlike most disasters, droughts normally occur slowly but last a long time. On average, the nationwide annual impacts of drought are greater than the impacts of any other natural hazard. They are estimated to cost between $6 billion and $8 billion annually in the United States and occur primarily in the agriculture, transportation, recreation and tourism, forestry, and energy sectors. Social and environmental impacts are also significant, although it is difficult to put a precise cost on these impacts.
Drought eventually affects groundwater sources but generally not as quickly as surface water supplies; however, groundwater supplies generally take longer to recover. Reduced precipitation during a drought means that groundwater supplies are not replenished at a normal rate. This can lead to a reduction in groundwater levels and problems such as reduced pumping capacity or wells going dry. Shallow wells are 1-26-2022 Submittal EXHIBIT A Page 117 of 416
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more susceptible than deep wells. Reduced replenishment of groundwater also affects streams since much of the flow in streams comes from groundwater, especially during the summer when there is less precipitation and after snowmelt ends. Reduced groundwater levels mean that even less water will enter streams when stream flows are lowest.
A drought can result in farmers not being able to plant crops or the failure of planted crops. This results in loss of work for farm workers and those in food processing and winemaking jobs. Other water-dependent industries are commonly forced to shut down all or a portion of their facilities, resulting in further layoffs.
A drought can harm recreational companies that use water (e.g., swimming pools, water parks, and river rafting companies) as well as landscape and nursery businesses because people will not invest in new plants if water is not available to sustain them.
Table 4-21 describes the impacts of the various severity levels of drought in California according to the National Drought Monitor classifications.
4.5.2.6 Warning Time
Droughts are climatic patterns that occur over long periods of time. Only generalized warning can take place due to the numerous variables that scientists have not pieced together well enough to make accurate and precise predictions. Predicting drought depends on the ability to forecast precipitation and temperature. Meteorologists can often predict the likelihood of high heat weeks in advance by monitoring ocean temperatures and world-wide weather patterns; however, predicting precipitation is more difficult.
Anomalies of precipitation and temperature may last from several months to several decades. How long they last depends on interactions between the atmosphere and the oceans, soil moisture and land surface processes, topography, internal dynamics, and the accumulated influence of weather systems on a global scale. (National Institute of Water and Atmospheric Research, 2016)
4.5.2.7 Secondary Hazards
The secondary hazard most associated with drought is wildfire. A prolonged lack of precipitation dries out vegetation, which becomes increasingly susceptible to ignition as the duration of the drought extends.
4.5.2.8 Drought Vulnerability Analysis
All people, property, and environments in the city planning area would be exposed to the impacts of moderate to extreme drought conditions to some degree. Drought produces a complex web of impacts that spans many sectors of the economy and reaches well beyond the area experiencing physical drought. This complexity exists because water is integral to the ability to produce goods and provide services. Drought vulnerability of an activity usually depends on its water demand, how the demand is met, and what water supplies are available to meet the demand. California’s 2018 Water Plan indicates that water demand in the state will continue to increase.
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Population
The residents of the city rely on healthy watersheds to provide adequate water for domestic and agricultural purposes. The City of Napa has experienced population growth and is projected to continue growing. During drought years, the reduced availability of water supplies for irrigation and food processing has been associated with poor water quality and historical outbreaks of gastrointestinal illness and other infections. Contaminants can be spread quickly during infrequent storms, which result in agricultural and urban runoff that can transmit contaminants and pathogens. (California Senate Office of Research, 2018) The effects of drought are otherwise limited as life or health impacts within the planning area.
Property
During drought years, property owners with shallow wells can be impacted by drought with increased demand on groundwater resources. Surface water supplies are often lower, which can reduce available supplies and increase cost. This sometimes encourages growers who historically use surface water to switch to groundwater, which has a permanent impact on those reliant on groundwater.
No structures will be directly affected by drought conditions, though some structures may become vulnerable to wildfires, which are more likely following years of drought. Droughts can also have significant impacts on landscapes, which could cause a financial burden to property owners. However, these impacts are not considered critical in planning for impacts from the drought hazard.
The agricultural sector is particularly susceptible to drought impacts. Agricultural drought impacts are normally felt earliest by those relying on unmanaged water supplies, such as entities carrying out dryland grazing and non-irrigated crop production, usually grain crops. Impacts on irrigated agriculture depend on the source and nature of the irrigation water supply, whether it be local groundwater, local surface water, or imported surface water, and any water rights or contractual provisions that may be associated with the source. The extent to which producers may mitigate water shortage impacts depends on multiple factors but is heavily influenced by economic considerations. Factors involved in making decisions about mitigating irrigation water shortages include availability and costs of pumping groundwater, price of alternative surface water sources, capital investments associated with maintaining permanent plantings, and status of international crop markets. (California Drought Contingency Plan, 2010) Critical Facilities
Critical facilities, as defined for this plan, will continue to be operational during a drought. Critical facility elements, such as landscaping, may not be maintained due to limited resources, but the risk to the planning area’s critical facilities inventory will be largely aesthetic. For example, when water conservation measures are in place, landscaped areas will not be watered and may die. These aesthetic impacts are not considered significant.
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4.5.2.9 Future Trends in Development
The City of Napa will face challenges in providing sufficient water supplies in the future due to climate change effects, coupled with an increasing population, mostly in the incorporated areas, and increasing water demand. The City has already taken steps towards achieving long-term sustainability for water availability, in particular through requiring new development to offset water usage by retrofitting existing structures with water-efficient infrastructure (low-flow toilets in particular) and some building code requirements above and beyond CALGreen. There is still a possibility that water supply availability may change in the future and will need to be further addressed. The City will examine these future concerns as it updates its General Plan (currently underway), which will set long-term policies to continue leadership in water conservation.
The Watershed Information and Conservation Council exists to inform and educate the public and water community about water issues in the County of Napa. They are a resource for information on water issues in Napa County, including the City of Napa, and provide tips for water conservation.
4.5.2.10 Climate Change Impacts
The long-term effects of climate change on regional water resources are unknown. Globally, water resources are already stressed from a growing population, poor water quality, groundwater overdrafts, and aging urban water infrastructure. Climate change will likely exacerbate many of these stresses.
With a warmer climate, droughts could increase in severity, frequency, and duration. According to the UC Davis Center for Watershed Sciences, water shortages in 2016 were projected to cost the agricultural industry a total of $550 million in direct costs and 1,815 lost jobs. More frequent extreme events, such as droughts, could end up being more cause for concern than the long-term change in temperature and precipitation averages. (University of California, Davis Center for Watershed Sciences, 2020)
4.5.2.11 Drought Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and drought hazard data.
Drought hazard problem statements for the City of Napa are listed in Table 4-22.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. See Table 5-6 for a full list of mitigation actions and corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-22 and Table 5-6. 1-26-2022 Submittal EXHIBIT A Page 120 of 416
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Table 4-22: Drought Problem Statements
Problem No.
Hazard
Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-DR-CN-29 Drought Impact PE&A - Public
Education &
Awareness , SP -
Structural
Projects
Climate change is expected to increase the
frequency and severity of drought events.
ma-DR-CN-16
ps-DR-CN-30 Drought Impact PRV - Prevention ,
SP - Structural
Projects
The City has not formally incorporated an
assessment of drought risk into the City’s
UWMP, as required by the Urban Water
Management Planning Act.
ma-DR-CN-53,
ma-DR-CN-55
ps-DR-CN-31 Drought Impact PE&A - Public
Education &
Awareness , NRP
- Natural
Resource
Protection
Drought impacts to the Napa Valley AVA
(American Viticultural Area) may negatively
affect local tourism.
ma-AH-CN-3,
ma-DR-CN-54
ps-DR-CN-32 Drought Impact PRV - Prevention ,
SP - Structural
Projects
City currently does not have adequate
infrastructure for resiliency in extreme
drought instances.
ma-DR-CN-16,
ma-DR-CN-53,
ma-DR-CN-54,
ma-DR-CN-55
ps-DR-CN-33 Drought Threat PE&A - Public
Education &
Awareness
Community members and those served by
City water may not understand how to
reduce water consumption or the benefits of
such actions, especially in times of drought.
ma-DR-CN-54
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4.5.3 Climate Change Hazard Profile
Climate change refers to any distinct change in measures of climate lasting for a long period of time, more specifically major changes in temperature, rainfall, snow, or wind patterns. Climate change may be limited to a specific region or may occur across the whole Earth. Climate change may result from:
▪ Natural factors, such as changes in the sun’s energy or slow changes in the Earth’s orbit around the sun;
▪ Natural processes within the climate system, such as changes in ocean circulation; or ▪ Human activities that change the atmosphere’s make-up and the land surface, such as burning fossil fuels, cutting down forests, planting trees, or building developments in cities and suburbs.
Changes in extreme weather and climate events, such as heatwaves and droughts, are the primary way that most people experience climate change. Human-induced climate change has already increased the number and strength of these extreme events. Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures, heavy downpours, and severe floods and droughts in some regions. (EPA, 2021)
The effects of climate change are varied and include extremes in precipitation and temperature. Slower average increases in temperature, precipitation, and sea-level rise can result in compounding impacts, such as ocean acidification, increases insect outbreaks, and shifts in biological patterns, to name a few. (Food and Agriculture Organization of the United Nations, 2014) The effects of climate change are wide-ranging and include warmer and more varied weather patterns, melting ice caps, and poor air quality, for example. As a result, climate change will likely worsen a number of natural hazards, including wildfire, flood, drought, and extreme weather. Table 4-23 is a list of localized climate change impacts relevant to the Napa region and the reference to where it is addressed in this HMP.
Sea-level rise, a direct result of climate change and related to flooding, is projected to affect communities in the San Francisco Bay Area, including southern parts of the City of Napa. Sea-level rise has the potential to inundate homes, businesses, and infrastructure and cause erosion near shorelines and in delta areas of rivers.
Table 4-23: Climate Change-Related Hazards and Cross-References in HMP Climate Change Hazard Reference in HMP
Agriculture and Forestry Pests and Diseases Section 4.5.8.1.1 (Sudden Oak Death in Wildfire Profile) Drought Section 4.5.2 (Drought Hazard Profile)
Inland and Riverine Flooding Section 4.5.6 (Flood Hazard Profile) Extreme Weather Section 4.5.7 (Extreme Weather Hazard Profile) Wildfire Section 4.5.8 (Wildfire Hazard Profile)
Extreme Heat Section 4.5.3.5 (Climate Change Severity & Extent) 1-26-2022 Submittal EXHIBIT A Page 123 of 416
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California is already experiencing the impacts of climate change, including prolonged drought, increased coastal flooding and erosion, and tree mortality. The state has seen increased average temperatures, more extreme heat days, fewer cold nights, a lengthening of the growing season, shifts in the water cycle with less winter precipitation falling as snow, a decreased summertime fog of 33 percent, and both snowmelt and rainwater running off sooner in the year. (Cal OES, 2018) Long term trends in fog depict a decline of some 12 to 20 percent in California from 1900 through 2070. Climate experts suggest that warmer temperatures resulting from climate change create conditions where air fails to reach cool enough temperatures necessary for the production of fog. Warmer temperatures are simultaneously able to evaporate any fog which is able to form. (Grantham, Teodore; University of California, Berkeley, 2018) The intensity of extreme weather events is also increasing. Extreme weather events and resulting hazards, such as heatwaves, wildfires, droughts, and floods, are already being experienced. (Leah Fisher, Sonya Ziaja, 2018, p. 22) The vulnerability analysis herein touches on extreme weather impacts from climate change.
Methodology for Predicting Climate Change Impacts
Climate change impacts will vary depending on the amount of greenhouse gas (GHG) emissions and atmospheric GHG concentrations may change over time. Various climate models explore a range of emission scenarios globally. There are six representative GHG emission scenarios, called Representative Concentration Pathways (RCPs). The three most-used representative scenarios include a low-end scenario of GHG emissions (RCP 2.6), which incorporates strong GHG emission reductions now and in the future, a moderate scenario (RCP 4.5), which incorporates stabilizing GHG emissions through 2050, and a high-end (RCP 8.5), which maintains a fossil fuel-intensive, “business-as-usual” emission scenario.
Mapping in this HMP uses the moderate RCP 4.5 emissions scenario and the high emissions RCP 8.5 scenario to consider both the ramifications of a worst-case scenario for adaptive planning and to consider how curbing emissions might reduce the most dramatic consequences. (OPR Planning and Investing for a Resilient California, p. 19)
Sea-Level Rise
Another outcome of global climate change is sea-level rise. The sea level rose during the 20th century, and observations and projections suggest that it will rise at a higher rate during the 21st century. Rising seas increase the risk of coastal flooding, storm surge inundation, coastal erosion and shoreline retreat, and wetland loss. The cities and infrastructure that line many coasts are already vulnerable to damage from storms, which is likely to increase as sea level continues to rise and inundate areas further inland.
Around the world, sea level is rising primarily because global temperatures are rising, causing ocean water to expand and land ice to melt. Sea-level rise along the Pacific coast depends on the global mean sea-level (GMSL) rise and also on regional factors, such as ocean and atmospheric circulation patterns in the northern Pacific Ocean, gravitational and deformational effects of land ice mass changes, and tectonics along the coast. (Sea-Level Rise for the Coasts of California, Oregon, and Washington, 2012) Areas exposed 1-26-2022 Submittal EXHIBIT A Page 124 of 416
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to sea level rise are depicted in Figure 4-23, and Table 4-24 depicts the probability of exceeding the GMSL in different scenarios under different RCPs by 2100.
Table 4-24: Probability of Exceeding Global Mean Sea-Level Rise (Median Value) Scenarios in 2100 GMSL Rise Scenario RCP 2.6 RCP 4.5 RCP 8.5
Low (0.3 m) 94% 98% 100%
Intermediate-Low (0.5 m) 49% 73% 96%
Intermediate (1.0 m) 2% 3% 17%
Intermediate-High (1.5 m) 0.4% 0.5% 1.3%
High (2.0 m) 0.1% 0.1% 0.3%
Extreme (2.5 m) 0.05% 0.05% 0.1%
Source: National Oceanic and Atmospheric Administration (Based on Kopp et al. 2014) The National Oceanic and Atmospheric Administration (NOAA) sea-level rise scenario planning helps reveal the range of possible sea-level rise in the City of Napa. Mapping in this HMP uses the moderate range RCP 4.5 as well as the high-end range RCP 8.5. RCP 4.5 mapping looks at projected sea level rise outcomes in the later half of the century with an adaptive lens. (OPR Planning and Investing for a Resilient California, p. 19) Figure 4-23 shows predicted sea-level rise in the City of Napa. This mapping used the moderate range RCP 4.5.
The exposure and damage estimations for sea-level rise for the City of Napa are discussed further in the Vulnerability Assessment (Section 4.5.3.8).
Extreme Weather Conditions
As the world has warmed, that warming has triggered many other changes to the Earth’s climate. Changes in extreme weather and climate events, such as heat waves and droughts, are the primary way that most people experience climate change. Human-induced climate change has already increased the number and strength of these extreme events. Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures, heavy downpours, and severe floods and droughts in some regions. (National Climate Assessment, 2014)
Extended frost threat is another result of climate change. In February 2018, grape growers prepared for extended frost threat while coping with a lack of rainfall during what are typically the wettest months of the year. As climate change continues, bud break, or the appearance of shoots that will eventually yield grapes, will begin sooner, leaving the delicate new growth exposed to the hazards of frost and rain for a longer stretch of the growing season. (Lutz, 2018)
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Figure 4-23: City of Napa Sea-Level Rise Potential (RCP 4.5) 1-26-2022 Submittal EXHIBIT A Page 126 of 416
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4.5.3.1 Policies, Plans, and Regulatory Environment
Successful efforts to address the challenges of climate change begin at the local level and include the implementation of environmentally sustainable practices designed to meet present and future energy needs.
California Assembly Bill 2516: Database for Sea-Level Rise Planning AB 2516 directed the Natural Resources Agency in collaboration with the Ocean Protection Council to conduct biannual surveys of sea-level rise planning information to catalog California’s efforts to prepare for rising sea levels. Numerous studies, vulnerability assessments, and local coastal programs have been developed under this directive. AB 2516 resources are stored in the Adaption Clearinghouse (resilientca.org).
2019 California Green Building Standards
The City of Napa has adopted the 2019 California Green Building Standards, also known as CALGreen Code.
CALGreen Code establishes regulations for green construction of nonresidential and residential buildings.
Topics covered in the regulations include planning and design, energy efficiency, water efficiency and conservation, material conservation and resource efficiency, and environmental quality. The code also includes voluntary measures for residential, nonresidential, and health facilities.
California Sustainable Communities and Climate Protection Act of 2008 The Sustainable Communities and Climate Protection Act of 2008 (Sustainable Communities Act, SB 375, Chapter 728, Statutes of 2008) looks to reduce GHG emissions through coordinated transportation and land use planning with the goal of more sustainable communities. Regional targets are established for GHG emissions reductions from passenger vehicle use by the sustainable communities strategy (SCS) established by each metropolitan planning organization (MPO). The SCS is an integral part of regional transportation plans (RTP) and contains land use, housing, and transportation strategies to meet GHG reductions targets.
2018 California Coastal Commission Sea Level Rise Policy Guidance The 2018 California Coastal Commission Sea Level Rise Policy Guidance document provides an overview of the best available science on sea level rise for California and recommended methodology for addressing sea level rise in Coastal Commission planning and regulatory actions. It is intended to serve as a multipurpose resource for a variety of audiences and includes a high level of detail on many subjects. 2018 California’s Fourth Climate Change Assessment
California’s Fourth Climate Change Assessment promotes actionable science that serves the growing needs of state and local decision-makers from a diverse number of sectors. The Fourth Assessment 1-26-2022 Submittal EXHIBIT A Page 127 of 416
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provides information in a number of ways. Regional reports summarize climate impacts and adaptation needs around the state as a resolution useful for local decision-makers. Statewide impacts are summarized in the Statewide Summary Report, as well as in reports on Tribal and Indigenous Communities, Climate Justice, and California’s Ocean and Coast. The Technical Reports are the foundation of the Fourth Assessment and include climate projections and analyses of expected impacts in various sectors across the state.
2020 California Adaptation Planning Guide (APG)
California has been taking action to address climate change for over 20 years, focusing on both greenhouse gas emissions reduction and adaptation. Cal OES’s Adaptation Planning Guide (APG) provides guidance and support for communities addressing the unavoidable consequences of climate change. The 2020 APG presents an updated, step-by-step process that communities can use to plan for climate change.
California Senate Bill 379: General Plan Safety Element and Climate Adaption California SB 379 requires cities and counties to include climate adaptation and resiliency strategies in the Safety Elements of their General Plans upon the next revision beginning January 1, 2017. The bill requires the climate adaptation update to include goals, policies, objectives, and implementation actions for their communities based on a climate vulnerability assessment, including a discussion of conserving and protecting natural infrastructure that serves an adaptation function.
California Senate Bill 1000: General Plan Safety and Environmental Justice Elements Senate Bill (SB) 1000 requires local governments to include an Environmental Justice Element in General Plans. SB 1000 has four basic requirements, whether those requirements are combined into a single Environmental Justice Element or distributed throughout other existing elements, including:
▪ Identifying disadvantaged communities;
▪ Incorporating policies to reduce the environmental health impacts that adversely affect residents in disadvantaged communities;
▪ Incorporating policies to include residents of disadvantaged communities in decision-making processes; and
▪ Incorporating policies that prioritize improvements and projects in disadvantaged communities.
The City is currently updating its General Plan and will integrate climate change policies and programs as part of the update, consistent with state requirements since the 2015 plan. 2012 City of Napa Sustainability Plan
In 2012, the City of Napa City Council adopted the city’s first Sustainability Plan. The plan includes steps for reducing greenhouse gas emissions and specifically includes the creation of five “green teams” centered around energy, transportation, water, recycling and waste, and planning and land use. The 1-26-2022 Submittal EXHIBIT A Page 128 of 416
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objectives for each team include the reduction of energy, emissions or waste, the conservation of water, and the increased design of green building.
Environmental Sustainability in City of Napa Municipal Code, § 15.30 Chapter 15 of the Napa municipal code outlines what are called “high performance building regulations,” which are those additional requirements above and beyond CALGreen building code. Requirements focus on energy and resource efficiency and reducing waste and pollution generation.
4.5.3.2 Past Events
Climate change has never been directly responsible for any declared disasters to date. Past flooding, wildfire, and drought disasters may have been exacerbated by climate change, but it is difficult to make direct connections to individual disasters. In addition, unlike earthquake and floods that occur over a finite time period, climate change is an on-going hazard, and many communities are already experiencing the effects. Other effects may not be seriously experienced for decades or may be avoided altogether by mitigation actions taken today.
Sea-Level Rise
Historic records from the San Francisco tidal gage, CA Station ID: 9414290, show that the sea level in the San Francisco Bay has risen eight inches from 1897 to 2006. Similarly, water level measurements from the tidal gage at Port Chicago, CA Station ID: 9415144, show an increase in mean sea level of 2.08 millimeters a year, which is equivalent to a change of 8.6 inches in 100 years. (NOAA, 2021)
4.5.3.3 Location
The effects of climate change are not limited by geographical borders. The City of Napa, the State of California, the United States, and the rest of the world are all at risk of climate change. As such, the entire city is at risk to the effects of climate change.
The City of Napa is located adjacent to the Napa River in the southern portion of the Napa Valley, 52 miles northeast of San Francisco and 61 miles west of Sacramento. Much of the city is on relatively level ground; however, the eastern and western edges of the area extend into brush and oak-covered foothills. The city’s northern edge transitions into agricultural lands, primarily vineyards. The southern end of the city abuts agricultural and marsh lands.
Sea-Level Rise
Sea-level rise varies greatly depending on a number of factors. Globally, sea level is rising primarily because global temperatures are rising, causing ocean water to expand and land ice to melt. However, sealevel rise varies from place to place. Sea-level rise along the Pacific coast depends on the global mean sealevel rise and also on regional factors such as ocean and atmospheric circulation patterns in the northern Pacific Ocean, gravitational and deformational effects of land ice mass changes, and tectonics along the coast. The comparative importance of these factors determines whether local sea level is higher or lower 1-26-2022 Submittal EXHIBIT A Page 129 of 416
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than the global mean, and how fast it is changing, which has enormous implications for coastal planning. (National Research Council, 2012)
Sea-level rise within the Western Pacific is different than the global average. In some places within the Western Pacific, sea-level rise has been greater than 10 millimeters per year. In other places, such as in the Eastern Pacific, sea-level rise has been much less. The differences in rate and region are primarily associated with multi-decadal fluctuations that are associated with the Pacific Decadal Oscillation (PDO), which has appeared to switch phases in the last couple of years. A PDO phase switch could signal the start of higher amounts of relative sea-level rise along the U.S. West Coast within the coming decades. This is a trend similar to the higher relative sea-level rise rates which have occurred in this region during portions of the last century. (NOAA, 2017)
4.5.3.4 Frequency and Probability of Future Occurrences Climate change is one of the few natural hazards where the probability of occurrence is influenced by human action. In addition, unlike earthquake and floods that occur over a finite time period, climate change is an ongoing hazard.
Temperature-related impacts are the most likely near-term climate change exposure facing the City of Napa and should be addressed and prioritized in future adaptation planning efforts. While sea-level rise has a high certainty rating and is already occurring, its onset is not expected to occur until closer to the end of the century in terms of changes in areas already vulnerable to flooding or causing permanent inundation in tidally-influenced areas of the city. (National Oceanic and Atmospheric Administration, n.d.) California’s Fourth Climate Change Assessment (2018) delineates how climate change may impact and exacerbate natural hazards in the future, including wildfires, extreme heat, floods, and drought. Climate change is expected to lead to increases in the frequency, intensity, and duration of extreme heat events and heat waves in the City of Napa and the rest of California, which are likely to increase the risk of mortality and morbidity due to heat-related illness and exacerbation of existing chronic health conditions.
Those most at risk and vulnerable to climate-related illness are the elderly and infants; individuals with chronic conditions, such as heart and lung disease, diabetes, and mental illnesses; the socially or economically disadvantaged; and those who work outdoors.
Higher temperatures are predicted to reduce snowpack in California, reducing water supply statewide. At the same time, droughts are predicted to increase in frequency and intensity. Further, intense rainfall, creating more frequent and intense flooding, will continue to affect California. (California's Fourth Climate Change Assessment, 2018) These same factors are predicted to worsen wildfires and pestilent insects through fuel hazards and ignition risks. An increase in wildfire intensity and extent will increase public safety risks, property damage, fire suppression and emergency response costs, watershed and water quality impacts, vegetation conversions, and habitat fragmentation. 1-26-2022 Submittal EXHIBIT A Page 130 of 416
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Sea-Level Rise
The probability for sea-level rise varies depending on the amount of sea-level rise predicted. Sea-level rise predictions vary from a low of 0.3 meters to the highest of a 2.5-meter global mean sea-level rise. The probability of different levels of sea-level rise also depends on the amount of future GHG emissions and reductions made. Table 4-24 shows the probability of various levels of sea-level rise by 2100 based on three RCPs. Under a business-as-usual scenario, RCP 8.5, there is a 96 percent chance of global sea-level rise of
0.5 meters. With reduced emissions under RCP 4.5, that chance is reduced to 73 percent. The probability of a one-meter global rise in sea levels is 17 percent under RCP 8.5, decreasing to a three percent chance with emissions reductions under RCP 4.5. The exposure and damage estimations for sea-level rise for the City of Napa are discussed further in the Vulnerability Assessment (Section 4.5.3.8).
4.5.3.5 Severity and Extent
Climate change severity and extent in the City of Napa is varied and can generally be categorized into several key effects. These effects are identified in the San Francisco Bay Area Region4 Report from California’s Fourth Climate Change Assessment (2018). General climate change impacts for this San Francisco Bay Area include:
▪ Predicted annual maximum temperatures will increase by 4.2°F under the RCP 4.5 scenario and
7.2°F under the RCP 8.5 scenario by the end of the 21st century. (Ackerly, 2018, p. 14) See Figure 4-24 to compare current annual average maximum temperatures with those predicted for the City of Napa in 2100.
▪ Annual precipitation is likely to be delivered in more intense storms, with shorter wet seasons and prolonged dry seasons.
▪ An “average” rainfall year will become less common with a higher occurrence of extreme wet and dry years.
▪ Increased extreme weather events will increase the severity and extent of flooding. ▪ Stream flows in the summer dry season are predicted to decline, and peak flows in the wetter winter months are likely to increase.
▪ Sea-level rise is predicted to increase by at least two meters over the next several centuries. ▪ Wildfires will continue, with projections for a longer wildfire season, increased frequency, and expansion of the area susceptible to fire. (Grantham, 2018) ▪ Frost occurrences may become longer and more frequent. In February 2018, for example, grape growers prepared for extended frost threat, while coping with a lack of rainfall during what are typically the wettest months of the year. As climate change continues, bud break, or the appearance of shoots that will eventually yield grapes, will begin sooner, leaving the delicate new growth exposed to the hazards of frost and rain for a longer stretch of the growing season. (Lutz, 2018) 4 The San Francisco Bay Area Region for California’s Fourth Climate Change Assessment includes Marin, Napa, Sonoma, Solano, Alameda, San Mateo, Contra Costa, Santa Clara, and San Francisco Counties. 1-26-2022 Submittal EXHIBIT A Page 131 of 416
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These impacts are predicted to significantly impact communities through habitat loss, including for coldwater fish species such as salmon, increased flood and landslide risks to critical infrastructure, and increased public health risks from wildfire, floods, heatwaves, and disease vectors. (Id.) Current and Projected Average Maximum Temperatures Under RCP 4.5 and 8.5 Scenarios Overall temperatures in California projected to rise by 5.6°F under an RCP 4.5 scenario and 8.8°F under an RCP 8.5 scenario by the end of this century. (Bedsworth, 2018, p. 23) Table 4-25 and Table 4-26 depict average maximum temperature increases throughout the City of Napa. They are modeled for future projections, beginning in 2006 and ending in 2099. There are four models that are depicted in these tables.
HadGEM2-ES has been termed the “warm/dry model,” and is weighted in rank closest to one across all metrics and RCPs. CanESM2 is the average model, which has a weighted rank closest to the average value across all metrics and RCPs. This is the model utilized throughout this document for climate change projections. The “cool and wet model” is CNRM-CMC5 and has a weighted rank closest to 10. MIROC5 gives a more comprehensive range of the 10 California global climate model results. (Scripps Institution of Oceanography , 2018)
Table 4-25: Annual Average Maximum Temperatures under RCP4.5 Source: CalAdapt 2020
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Table 4-26: Annual Average Maximum Temperature under RCP8.5 Source: CalAdapt 2020
Figure 4-24 compares annual averages of observed and projected maximum temperature values for the City of Napa region under current conditions, RCP 4.5, and RCP 8.5 emissions scenarios, respectively.
Under the RCP 4.5 scenario, the city is projected to experience increases in maximum temperatures near 80°F. Under the RCP 8.5 scenario, portions of the city are projected to experience maximum temperatures closer to 86°F.
These projections differ depending on the time of year and the type of measurement (highs vs. lows), all of which have different potential effects to the city’s ecosystem health, agricultural production, water use and availability, and energy demand.
Sea-Level Rise
Generally, some amount of sea-level rise is projected for the mouth of the Napa River in the City of Napa.
The severity and extent of sea-level rise depends greatly on the future pathways for emission levels and how far into the future the analysis looks. Figure 4-23 shows predicted sea-level rise in the City of Napa based on low through extreme amounts of rise, with various vulnerabilities to such sea-level rise. See Section 4.5.3.4 for an overview of frequency and probability of occurrence, which plays directly into the severity and extent of sea-level rise.
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Figure 4-24: City of Napa Comparison of Observed and Projected Annual Max Temps 1-26-2022 Submittal EXHIBIT A Page 134 of 416
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4.5.3.6 Warning Time
Many existing hazards could be intensified as a result of climate change, decreasing warning times and exacerbating impacts. Warning times are discussed under the various other hazards. Other climate change impacts are more long-term. Scientists have a high confidence in predicting the rise in global temperatures and have reached a consensus on the future impacts of climate change and the time frame in which they will occur.
Sea-Level Rise
Sea-level rise will occur slowly over time and increase impacts of other hazards profiled in the HMP, such as shoreline erosion and the potential impacts of tsunamis.
4.5.3.7 Secondary Hazards
Secondary hazards of climate change include flood, extreme weather, drought, wildfire, sea-level rise, extreme heat, and heavy rain events. Climate change will also increase the frequency at which extreme weather events occur. Secondary hazards of climate change that will have the greatest impact on the City of Napa include flood, wildfire, drought, and extreme weather. Many of these impacts are discussed in other hazard profiles.
Sea-Level Rise
Sea-level rise is projected for the mouth of the Napa River in the City of Napa as a secondary hazard associated with Climate Change. See Section 4.5.3.5 for sea-level rise projections for the City of Napa shoreline.
4.5.3.8 Vulnerability Assessment
This section outlines vulnerabilities of the City of Napa to impacts from climate change and focuses on sea-level rise in particular, as many of the other impacts are secondary and outlined in other hazard profiles within this document. Sea-level rise also has delineated hazard boundaries and quantifiable exposure and damage estimations. This HMP Vulnerability Assessment summarizes population (including vulnerable populations in a more general context), property, and critical facilities within known hazard areas. Figure 4-25 summarizes city vulnerability to sea level rise. 1-26-2022 Submittal EXHIBIT A Page 135 of 416
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Figure 4-25: City of Napa Sea-Level Rise Vulnerability and Exposure Snapshot 1-26-2022 Submittal EXHIBIT A Page 136 of 416
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Population
Increased extreme heat events is just one climate change impact that vulnerable populations are more susceptible to. Higher frequency of extreme heat conditions can cause serious public health impacts, increasing the risk of conditions directly related to heat such as heat stroke and dehydration. Older adults, particularly seniors, are more likely to experience respiratory and cardiovascular health complications than younger individuals and are more likely to live alone with limited mobility. Approximately 8,500 or a quarter of all city residents are 65 or older. These conditions create the potential to exacerbate health risks associated with extreme heat. (Id.)
A portion of the city’s population is a unique combination of low-income, primarily Spanish-speaking, and agriculturally-employed persons. These characteristics leave this population especially vulnerable to heat stress. Heat stress can seriously affect those working outside by reducing overall productivity and, in extreme conditions, can lead to illness, disability, or death. It has been found that Hispanics have been found to have an approximately nine percent greater risk of respiratory diseases than Caucasians in California during heat waves. (California Senate Office of Research, 2018) Sea-Level Rise
As sea levels rise, the area and the number of people at risk because of flooding will also rise. Factors that increase vulnerability to the adverse impacts of flood events associated with sea-level rise include access to preparedness information, transportation, healthcare, and insurance. Key demographics associated with these vulnerabilities include income, race, linguistic isolation (i.e., non-English speaking), educational attainment, and residential tenure. (R. Dean Hardy, Mathew E. Hauer, 2018, p. 13). Language ability is an important factor in assessing vulnerability as emergency response crews may be unable to communicate with non-English speakers. The estimated population exposed to sea-level rise is summarized in Table 4-27.
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Table 4-27: Population Exposure to Sea-Level Rise
Total Population
City of Napa 79,722
Sea Level Rise (Feet) Population Count % of Total
1ft 354 0.44%
2ft 445 0.56%
3ft 712 0.89%
4ft 792 0.99%
5ft 838 1.05%
6ft 913 1.15%
Table 4-28: Population Exposure to Sea-Level Rise by Degree Property
Climate change could significantly impact the agricultural and wine industries, which are large drivers of the City of Napa’s economy. Specifically, the agricultural industry provided approximately 2,793 jobs in the City of Napa in 2017 and made up approximately six percent of total city employment. This industry could be especially impacted as climate variability interferes with crop production. (Bay Area Council Economic Institute, 2019)
Increases in temperature and changes in precipitation and soil moisture could impact the growth of wine grapes by causing late or irregular blooming and affecting yields. The increased likelihood of extreme floods could lead to the destruction of crops, erosion of topsoil, and deposits of debris and sediment on croplands. Conversely, as average temperatures increase with climate change, agricultural demand for water could intensify under extreme heat conditions, under which water evaporates faster and plants need more water to move through their circulatory systems to stay cool. More specifically, attempts to maintain wine grape productivity and quality in the face of warming may be associated with increased water use for irrigation, a change to different varietals of grapes, and to cool grapes through misting or sprinkling. As 354
445
712
792
838
913
-
100
200
300
400
500
600
700
800
900
1,000
1ft 2ft 3ft 4ft 5ft 6ft
Population
Sea Level Rise
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noted earlier, increased average temperatures and changes in timing and amounts of precipitation could affect local aquifer recharge for groundwater supplies in the future, which could in turn affect water supplies for agricultural uses.
Sea-Level Rise
The City of Napa is vulnerable to sea-level rise to a limited extent. The Napa River is predicted to experience flooding events due to sea level rise in the San Pablo Bay. Approximately one percent of the general population would be at risk of exposure. A limited number of parcels would be exposed as well, depending on the amount of predicted rise. See Table 4-29 and the summary of exposure in Figure 4-25.
Areas farther north along the Napa River, at the southern portion of the city, include some industrial uses, wineries, and parts of downtown Napa (i.e., up to 3rd Street and portions east of State Route 29). Just south of the city, the Milton Road and Edgerly Island area could be lost in its entirety if the privately-owned levee system were to fail. (Napa County Climate Action Plan, 2018) Table 4-29: Parcels Exposed to Sea Level Rise
Total Parcels Total Market
Value ($)
Total Content
Value ($) Total Value ($)
City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Sea Level Rise Parcel Count % of Total Market Value
Exposure ($)
Content Value
Exposure ($) Total Exposure ($) % of Total
1ft - 0% $0 $0 $0 0%
2ft 2 0% $2 $2 $4 0%
3ft 6 0% $132,119 $198,176 $330,295 0%
4ft 8 0% $2,910,023 $4,365,032 $7,275,055 0%
5ft 9 0% $2,910,024 $4,365,033 $7,275,057 0%
6ft 13 0% $3,824,470 $5,279,479 $9,103,949 0%
Critical Facilities
Some critical infrastructure (e.g., roads, hospitals, schools, and emergency facilities) are at an increased risk of flooding in the city. For example, the Kennedy Park communication towers could become vulnerable to flood events associated with six feet of sea-level rise.
Sea-Level Rise
Critical facilities are summarized in the snapshot of sea-level rise in Figure 4-25 and Table 4-30 and Table 4-31 summarize critical infrastructure exposed to sea-level rise in the City of Napa. 1-26-2022 Submittal EXHIBIT A Page 139 of 416
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Table 4-30: Critical Infrastructure Points in Sea-Level Rise Regions Infrastructure Type 1ft 2ft 3ft 4ft 5ft 6ft
Essential Facility** - - - - - -
Fire Station - - - - - -
Hospital - - - - - -
Police Station - - - - - -
High Potential Loss - - 3 3 3 7
Adult Residential Facility - - - - - -
Child Care Center - - 2 2 2 2
Church - - - - - -
Communication Tower - - - - - 4
Dam - - - - - -
Farm Worker Housing - - - - - -
Foster Family Agency - - - - - -
Historic Building - - - - - -
Home Care Organization - - - - - -
Library - - - - - -
*Real Property Asset - - 1 1 1 1
Residential Child Care - - - - - -
Residential Elder Care Facility - - - - - -
School - - - - - -
Stream Rain Gauges - - - - - -
Water Treatment Plant - - - - - -
Transportation and Lifeline - - - - - -
Bridge - - - - - -
Power Plant - - - - - -
Pressure Regulator Station - - - - - -
Pump Station - - - - - -
Sample Station - - - - - -
Substation - - - - - -
Water Tank - - - - - -
Grand Total - - 3 3 3 7
*Real Property Assets are digitized insurance rolls for demonstrating value and ownership. ** Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here.
Table 4-31: Miles of Critical Infrastructure (Linear) in Sea-level Rise Regions Infrastructure Type (Linear) 1ft 2ft 3ft 4ft 5ft 6ft
Levee 0.1 0.2 0.2 0.2 0.2 0.2
Levee Centerline - - - 0.0 0.0 0.0
Levee Flood Wall - - - - - -
NG Pipeline 0.1 0.4 0.8 1.2 1.5 1.7
Railroad 0.2 0.5 2.2 2.7 2.8 2.9
Street 0.2 0.6 2.1 2.5 3.0 3.4
Alley - - - - - -
Cul-de-sac - - 0.0 0.1 0.1 0.1
Driveway - - - - - -
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Infrastructure Type (Linear) 1ft 2ft 3ft 4ft 5ft 6ft
Interstate - - - - - -
Local road - - - - - -
Local road, major 0.1 0.3 1.6 1.9 2.4 2.6
Primary highway 0.1 0.2 0.3 0.3 0.3 0.3
Ramp - - - - - -
Road, parking area - - - - - -
State/county highway 0.0 0.0 0.2 0.2 0.2 0.2
Thoroughfare, major - 0.0 0.1 0.1 0.1 0.2
Traffic circle - - - - - -
Transmission Line 0.4 0.6 0.7 0.7 0.8 0.9
Water Transmission Line* 0.0 0.1 0.2 0.2 0.3 0.3
Grand Total 1.0 2.3 6.1 7.5 8.7 9.4
** Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here.
4.5.3.9 Future Trends in Development
The City of Napa is committed to continuing efforts to address and reduce existing climate-related risks and future impacts on a holistic and programmatic level. With several ordinances and programs that cover a range of climate exposures and related impacts, the city is well equipped to handle current issues of extreme heat events and water supply issues but could still likely face increasing challenges as projected changes occur.
The city has practices and organizations in place that help address future issues of sustainability and climate adaptation and the City adopted a Sustainability Plan in 2012. The plan focuses on increasing sustainability in city government operations and provides guidance on how citizens and businesses can make cost-effective and sustainable choices. The City has also adopted the Green Building Standards Code, which exemplifies the actionable steps that the city is taking in order to set a precedent for reduced energy use, building with more sustainable materials, and employing better water conservation tactics, along with additional high performance building regulations aimed at emission reductions for new development.
The City has also authorized membership in the Marin Clean Energy (MCE) program, which allows users to purchase more renewable energy options as part of a progressive assembly bill called Community Choice Aggregation. City homes and businesses have begun receiving the power agency’s default service, which affords all current PG&E customers the option of having 50 to 100 percent of their electricity sourced from renewable resources. However, these efforts need to be expanded and applied on a much larger scale, along with mitigations actions identified in this HMP, to address future changes attributed to climate change. (City of Napa, n.d.)
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4.5.3.10 Climate Change Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and climate change data.
Climate change hazard problem statements for the City of Napa are listed in Table 4-32.
Identifying these common issues and weaknesses assists the Planning Committee in understand the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. Projects or actions have been developed to mitigate each problem identified. See Table 5-6 for a full list of mitigation actions and corresponding problem statements that they address. Each problem statement is coded with a problem number for cross-referencing between Table 4-32 and Table 5-6.
Table 4-32: Climate Change Problem Statements
Problem No. Hazard Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-CC-CN-0 Climate
Change
Impact SP - Structural
Projects
The City's water system requires additional
capacity to serve increased demand during
high heat events.
ma-DR-CN-16
ps-CC-CN-1 Climate
Change
Impact PE&A - Public
Education &
Awareness
Citizens are unaware of actions City is taken
and actions they can take that may reduce
climate impacts.
ma-AH-CN-3,
ma-AH-CN-5
ps-CC-CN-2 Climate
Change
Victim TBD - See notes Vulnerable populations need access to cooling centers for high heat events.
ma-AH-CN-3,
ma-CC-CN-51
ps-CC-CN-3 Climate
Change
Victim TBD - See notes Many Napa residents do not have air conditioning in their homes.
ma-CC-CN-51,
ma-AH-CN-3
ps-CC-CN-4 Climate
Change
Victim PPRO - Property
Protection , PE&A
- Public
Education &
Awareness
Residents of Mobile Home Parks are at an
increased risk of the impacts of climate
change.
ma-CC-CN-51
ps-CC-CN-17 Climate
Change
Victim PRV - Prevention ,
PE&A - Public
Education &
Awareness
Climate change is expected to lead to
increases in the frequency, intensity, and
duration of extreme heat events and heat
waves in the City, which are likely to
increase the risk of mortality and morbidity
due to heat-related illness and exacerbation
of existing chronic health conditions
ma-CC-CN-51,
ma-CC-CN-14
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Problem No. Hazard Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-CC-CN-18 Climate
Change
Victim PPRO - Property
Protection , PE&A
- Public
Education &
Awareness , NRP
- Natural
Resource
Protection
Wildfires will continue, with projections for a
longer wildfire season, increased frequency,
and expansion of the area susceptible to fire
ma-WF-CN-41,
ma-WF-CN-42,
ma-WF-CN-44,
ma-WF-CN-45,
ma-WF-CN-47,
ma-WF-CN-48,
ma-WF-CN-50
ps-CC-CN-19 Climate
Change
Impact PRV - Prevention ,
PPRO - Property
Protection , SP -
Structural
Projects
The compounding effects of sea level rise,
king tide, and extreme weather events will
likely increase the frequency and severity of
flooding.
ma-FL-CN-23,
ma-FL-CN-24,
ma-FL-CN-27,
ma-FL-CN-28,
ma-FL-CN-29
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INTENTIONAL BLANK PAGE
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4.5.4 Earthquake Hazard Profile
Earthquake is the sudden shaking of the ground caused by the passage of seismic waves through Earth’s rocks. Seismic waves are produced when some form of energy stored in Earth’s crust is suddenly released, usually when masses of rock straining against one another abruptly fracture and “slip.” Earthquakes associated with this type of energy release are called tectonic earthquakes. The energy also can be released by elastic strain, gravity, chemical reactions, or even the motion of massive bodies. Earthquakes occur most often along geologic faults, which are narrow zones where rock masses move in relation to one another. (United States Geological Survey, n.d.)
Earthquakes have different properties
depending on the type of fault that causes
them. See Figure 4-26. The usual fault
model has a “strike” (that is, the direction
from north taken by a horizontal line in the
fault plane) and a “dip” (the angle from the
horizontal shown by the steepest slope in
the fault). The lower wall of an inclined fault
is called the footwall. Lying over the
footwall is the hanging wall. When rock
masses slip past each other parallel to the
strike, the movement is known as strikeslip faulting. Movement parallel to the dip is called dip-slip faulting. In dip-slip faults, if the hanging-wall block moves downward relative to the footwall block, it is called “normal” faulting; the opposite motion, with the hanging wall moving upward relative to the footwall, produces reverse or thrust faulting. As a fault rupture progresses along or up the fault, rock masses are flung in opposite directions and then spring back to a position where there is less strain. (Id.) Soil Liquefaction
Soil liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. Soil liquefaction and related phenomena have been responsible for tremendous amounts of damage in historical earthquakes around the world. Saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress, such as shaking during an earthquake or other sudden change in stress condition. The phenomenon is most often observed in saturated, loose, low-density or uncompacted, and sandy soils. Loose sand tends to compress when a load is applied. Dense sands, by contrast, tend to expand in volume or “dilate.” If the soil is saturated by water, which often occurs when soil is below the water table or sea level, then water fills the pore spaces between soil grains. (USGS, n.d.) See Figure 4-27 for the liquefaction potential in the City of Napa.
Figure 4-26: Earthquake Faulting
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Figure 4-27: City of Napa - Potential for Liquefaction
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Artificial Induction
Earthquakes are sometimes caused by human activities, including the injection of fluids into deep wells, pumping of groundwater, excavation of mines, and the filling of large reservoirs. In fluid injection, the slip is thought to be induced by premature release of elastic strain, as in the case of tectonic earthquakes, after fault surfaces are lubricated by the liquid. (USGS, n.d.)
4.5.4.1 Earthquake Classifications
Earthquakes are typically classified by either the amount of energy released, measured as magnitude, or the impact on people and structures, measured as intensity. (USGS, n.d.) Magnitude
The most common method for measuring earthquakes is magnitude, which measures the strength of earthquakes. While the majority of scientists generally use the Moment Magnitude (Mw) Scale to measure earthquake magnitude, the Richter (M) Scale is the most universally-known measurement. The magnitude of an earthquake relates to the total area of the fault that ruptured and the amount offset or displaced across the fault. As shown in Table 4-33, there are seven earthquake magnitude classes on the Mw scale, ranging from great to micro. A magnitude class of great can cause tremendous damage to infrastructure compared to a micro class, which results in minor damage to infrastructure. (Id.) Table 4-33: Earthquake Magnitude Classes (Mw)
Intensity
Intensity measures the effect of an earthquake in a particular location. Intensity decreases as the distance from the epicenter increases. The Modified Mercalli Intensity value assigned to a specific site after an earthquake has a more meaningful measure of severity to the nonscientist than magnitude because intensity refers to the effects experienced at that place. (United States Geological Survey) The lower numbers of the intensity scale generally deal with the manner in which the earthquake is felt by people while the higher numbers of the scale are based on observed structural damage. Structural engineers usually contribute information for assigning intensity values of VIII or above. Table 4-34 is an abbreviated description of the levels of Modified Mercalli Intensity. (Id.) Magnitude Class
Magnitude Range
(M = Magnitude) Description
Great M > 8 Tremendous damage
Major 7 <= M < 7.9 Widespread heavy damage
Strong 6 <= M < 6.9 Severe damage
Moderate 5 <= M < 5.9 Considerable damage
Light 4 <= M < 4.9 Moderate damage
Minor 3 <= M < 3.9 Rarely causes damage.
Micro M < 3 Minor damage
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Table 4-34: Modified Mercalli Intensity Level Descriptions Intensity Shaking Description/Damage
I Not felt Not felt except by a very few under especially favorable conditions.
II Weak Felt only by a few persons at rest, especially on upper floors of buildings.
III Weak
Felt quite noticeably by persons indoors, especially on upper floors of buildings.
Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations are similar to the passing of a truck. Duration estimated.
IV Light
Felt indoors by many, outdoors by few during the day. At night, some awakened.
Dishes, windows, doors disturbed; walls make cracking sound. Similar to aheavy truck striking a building. Standing motor cars rocked noticeably.
V Moderate Felt by nearly everyone, many awakened. Some dishes, windows broken.
Unstable objects overturned. Pendulum clocks may stop.
VI Strong Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.
VII Very
strong
Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.
VIII Severe
Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.
IX Violent
Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.
X Extreme
Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.
Source: USGS, Abridged from The Severity of an Earthquake, USGS General Interest Publication 1989-288-913 Ground Motion
Earthquake hazard assessment is also based on expected ground motion. This involves determining the annual probability that certain ground motion accelerations will be exceeded, then summing the annual probabilities over the time period of interest. The most commonly mapped ground motion parameters are the horizontal and vertical peak ground accelerations (PGA) for a given soil or rock type. Instruments called accelerographs record levels of ground motion due to earthquakes at stations throughout a region. These readings are recorded by state and federal agencies that monitor and predict seismic activity. (Pacific Northwest Seismic Network)
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due to lateral acceleration that a building should be able to withstand during an earthquake. PGA values are directly related to these lateral forces that could damage “short period structures,” such as singlefamily dwellings. Longer-period response components determine the lateral forces that damage larger structures with longer natural periods, such as apartment buildings, factories, high-rises, and bridges.
Table 4-35 lists the damage potential and perceived shaking by PGA factors, compared to the Mercalli scale. (USGS)
Table 4-35: Modified Mercalli Scale and Peak Ground Acceleration Potential Structure Damage Estimated PGA
Modified Mercalli Scale Perceived Shaking Resistant Buildings Vulnerable Buildings (%g) I Not Felt None None <0.17%
II-III Weak None None 0.17% - 1.4%
IV Light None None 1.4% - 3.9%
V Moderate Very Light Light 3.9% - 9.2%
VI Strong Light Moderate 9.2% - 18%
VII Very Strong Moderate Moderate/Heavy 18% - 34%
VIII Severe Moderate/Heavy Heavy 34% - 65%
IX Violent Heavy Very Heavy 65% - 124%
X - XII Extreme Very Heavy Very Heavy >124%
Note: PGA measured in percent of g, where g is the acceleration of gravity Sources: USGS, 2008; USGS, 2010
4.5.4.2 Plans, Policies, and Regulatory Environment
Alquist‐Priolo Earthquake Fault Zoning Act and Seismic Hazards Mapping Act (1972) The 1971 San Fernando Earthquake resulted in the destruction of numerous structures built across its path.
This led to passage of the Alquist‐Priolo Earthquake Fault Zoning Act in 1972. This Act prohibits the construction of buildings for human occupancy across active faults in the State of California. Similarly, extensive damage caused by ground failures during the 1989 Loma Prieta Earthquake focused attention on decreasing the impacts of landslides and liquefaction. This led to the creation of the Seismic Hazards Mapping Act, which increases construction standards at locations where ground failures are probable during earthquakes. Figure 4-28 displays these zones of required investigation in the City of Napa. 2019 California Building Standards Code
The 2019 California Building Code, adopted by the City of Napa effective January 2020, includes materials requirements, construction methods, and maintenance standards for earthquake protection and resiliency.
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City of Napa General Plan
The 2015 City of Napa General Plan includes a number of goals and policies in its Health and Safety Element to mitigate the effects of earthquakes. These goals and policies are designed to minimize the risk to life and property from seismic activity. The City is currently updating its General Plan and will update seismic safety policies and programs as part of the update.
Seismic Safety in City of Napa Municipal Code
The City of Napa municipal code includes many protections for seismic safety. Section 15.110 outlines the review, rehabilitation, and abatement of existing seismically unsafe buildings. For example, public notice is required if a building has been found to be potentially structurally hazardous following an earthquake.
Public notice standards require that building owners or agents post a notice inside the main entrance of the building. The notice is an earthquake warning which must state that the building contains unreinforced masonry and may constitute a severe threat to life safety in the event of an earthquake.
In the city’s zoning, Section 17.52.420 requires geotechnical and geologic assessments within the West Napa Fault Zone Area and other hillside areas to assure that geologic hazards are adequately mitigated.
4.5.4.3 Past Events
A number of significant (more than M4.5) earthquakes have occurred in and near the City of Napa over the last 20 years. See Table 4-36 for earthquake events M4.5 or higher since 2000. Two adjacent areas (central San Francisco Bay Area and South Napa) experienced earthquakes of M5.45 and M6.02 during 2007 and 2014, respectively. The August 2014 earthquake was the largest earthquake to impact the San Francisco Bay Area in over 25 years, and the first one to rupture on the surface since the M7.9 1906 earthquake. (United States Geological Survey, n.d.)
Table 4-36: Earthquakes in or near City of Napa M4.5 or Greater Since 2000 Date Location Magnitude (M)
09/03/2000 Northern California 4.9
08/03/2006 Northern California 4.5
10/31/2007 San Francisco Bay Area 5.45
08/24/2014 South Napa 6.02
Source: USGS
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4.5.4.4 Location
The Alquist-Priolo Act established earthquake fault zones in California. These Alquist-Priolo Earthquake Fault Zones encompass surface traces of active faults that have a potential for future surface fault rupture and are mapped as estimated fault locations across California. These zones require future investigation to determine the location of the fault and are referred to as zones of required investigation. Not all fault lines require additional investigation for development. Figure 4-28 shows the location of quaternary faults near the City of Napa.
According to USGS, the most likely faults to produce strong ground shaking in Napa County include the Northern Hayward and Rodgers Creek-Healdsburg in the west, Maacama in the northwest, Hunting CreekBerryessa in the north, Green Valley in the southeast, and West Napa in the south central. The Green Valley and West Napa faults are the only major faults that pass through Napa County boundaries. (Association of Bay Area Governments, 2014) See Figure 4-28 for locations of regional fault lines.
4.5.4.5 Frequency and Probability of Future Occurrences This plan utilizes two mapping tools for understanding the frequency and probability of an earthquake occurring at different faults in and around the City of Napa: the Uniform California Earthquake Rupture Forecast Version 3 (UCERF3)(see Figure 4-29) and the earthquake shaking potential for the City of Napa (see Figure 4-30). Both mapping tools are described in more detail below.
Importantly, these probabilistic maps were used to determine the earthquake scenario used for the vulnerability analysis. This plan focuses on the West Napa scenario because it is the scenario with the highest likelihood of severe shaking and of producing a M6.7 earthquake within the next 30 years. See Figure 4-31 for an overview map of the scenario and Section 4.5.4.5.1 for further explanation on why this scenario was chosen.
According to the California State Hazard Mitigation Plan, earthquakes large enough to cause moderate damage to structures, those of M5.5 or larger, occur three to four times a year statewide. Strong earthquakes of M6 to M6.9 strike on an average of once every two to three years. Major earthquakes of M7 to M7.9 occur in California about once every 10 years.
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Figure 4-28: Zones of Required Investigation
Note: Quaternary faults, as illustrated in red in Figure 4-28, are those active faults that have been recognized at the surface and which have evidence of movement in the past 1.6 million years – the duration of the Quaternary Period. 1-26-2022 Submittal EXHIBIT A Page 152 of 416
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30-Year Earthquake Probability (UCERF3)
Probability of earthquake events is based on the approximate location of earthquake faults within and outside the City of Napa region. The Uniform California Earthquake Rupture Forecast Version 3 (UCERF3)5 is a comprehensive model of earthquake occurrence for California. It represents the best available science for authoritative estimates of the magnitude, location, and likelihood of potentially damaging earthquakes in California. According to UCERF3 and as shown in Figure 4-29, the West Napa fault has a one to five percent probability of occurrence within 30 years and lies just south of the City of Napa. The Green Valley fault has a five to 15 percent probability of occurrence within 30 years, the highest probability affecting the City of Napa. The most recent earthquake to happen in the City of Napa area was a M6.02 earthquake, which happened in 2014 in southern Napa. (Id.)
Figure 4-29: Fault Probability Map for Napa County
5 Quaternary faults are those active faults that have been recognized at the surface and which have evidence of movement in the past 1.6 million years - the duration of the Quaternary Period.
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Earthquake Shaking Potential
The earthquake shaking potential map, Figure 4-30, shows potential seismic shaking from anticipated future earthquakes. It is probabilistic in the sense that the analysis takes into consideration the uncertainties in the size and location of earthquakes and the resulting ground motions that can affect a particular site. (CGS, 2020) It is also useful in understanding the probability of severe shaking in different locations throughout the city and nearby areas, as discussed in Section 4.5.4.5.1.
The map is expressed in terms of the probability of exceeding a certain ground motion. The map shows a two percent probability of exceeding one second of ground motion in 50 years. Earthquake shaking potential in California is calculated based on the USGS National Seismic Hazard Model and in partnership with California Geological Survey (CGS). Earthquake shaking potential also considers historic earthquakes, slip rates on major faults, deformation throughout the region, and the potential for amplification of seismic waves by near-surface geologic materials. (CGS, 2020)
The map depicts a range of lower hazard to higher hazard probability, where higher hazard areas are those regions near major, active faults that will on average experience stronger earthquake shaking more frequently. This intense shaking can damage even strong, modern buildings. Lower hazard areas are those regions that are distant from known, active faults that will experience lower levels of shaking less frequently. In most earthquakes, only weaker, masonry buildings would be damaged. However, very infrequent earthquakes could still cause strong shaking in those locations. (D. Branum, 2016) The shaking potential is calculated as the level of ground motion that has a two percent chance of being exceeded in 50 years, which is the same as the level of ground-shaking with about a 2500-year average repeat time. Relatively long-period (one second) earthquake shaking is shown. Long-period shaking affects tall, relatively flexible buildings, but also correlates well with overall earthquake damage. Although the greatest hazard is in areas of highest intensity, as shown in Figure 4-30, no region is immune from potential earthquake damage. (Id.)
The potential for earthquake ground shaking, as defined by the U.S. National Seismic Hazard Model, is used by engineers to design buildings for larger ground motions than are projected to occur during a 50-year interval, which will make buildings safer than if they were only designed for the ground motions expected to occur in the next 50 years. (USGS, 2020)
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Figure 4-30: City of Napa Earthquake Shaking Potential
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West Napa Earthquake Scenario
The West Napa earthquake scenario was chosen from a range of regional, scenario-based shakemaps available from USGS for the vulnerability analysis. The shakemap data consists of peak ground velocity, peak ground acceleration, and peak spectral accelerations in an earthquake scenario. The West Napa fault has the near highest probability of an earthquake greater than M6.7 nearest to the City of Napa, with a greater than five percent annual probability. See Figure 4-29 for this probability. Note that the Green Valley fault has a higher probability of activity, yet it is farther away than the West Napa fault. Likewise, the most significant shaking potential depicted in the shakemap in Figure 4-30 centers around the West Napa fault system, the epicenter of which is shown on the same spot. The M6.7 West Napa scenario is shown in Figure 4-31. Section 4.5.4.9 analyzes the city’s exposure to this scenario and Section 4.5.4.9.2 details damage estimation to residential properties and city facilities for this scenario.
4.5.4.6 Severity and Extent
As we know from past events, even a moderate earthquake occurring in or near the city could result in deaths, casualties, property and environmental damage, and disruption of normal services and activities.
The severity of the event could be aggravated by collateral emergencies, such as fires, hazardous material spills, utility disruptions, landslides, transportation emergencies, and the possible failure of the City of Napa dams.
Neither the occurrence of an earthquake nor the severity can be predicted. Instead, scientists can only calculate the probability that a significant earthquake will occur in a specific area within a certain number of years. The probabilistic earthquake shaking potential map, Figure 4-30, illustrates the areas near the city most likely to experience an earthquake exceeding one second of ground motion in 50 years, which aids in understanding locations in the City of Napa with the greatest probability of experiencing a severe earthquake. While the city and surrounding region are similarly susceptible to shaking, the greatest probability of a severe earthquake focuses on the West Napa fault.
4.5.4.7 Warning Time
There is currently no reliable way to predict the day or month that an earthquake will occur at any given location. Research is being done with warning systems that detect low energy waves that precede major earthquakes. Seconds and minutes of advance warning can allow people and systems time to take actions to protect life and property from destructive shaking. Even a few seconds of warning can enable protective actions specific to various sectors of the population, such as:
▪ Public: Citizens, including schoolchildren, drop, cover, and hold on; turn off stoves, safely stop vehicles.
▪ Businesses: Personnel move to safe locations, automated systems ensure elevator doors open, production lines are shut down, sensitive equipment is placed in a safe mode. ▪ Medical services: Surgeons, dentists, and others stop delicate procedures. ▪ Emergency responders: Open firehouse doors, personnel prepare and prioritize response decisions. ▪ Power infrastructure: Protect power stations and grid facilities from strong shaking. 1-26-2022 Submittal EXHIBIT A Page 156 of 416
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Figure 4-31: M 6.7 West Napa Scenario Earthquake Severity 1-26-2022 Submittal EXHIBIT A Page 157 of 416
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4.5.4.8 Secondary Hazards
Earthquakes can cause other hazards to occur, such as dam failure or fires. These are profiled in other parts of this plan.
4.5.4.9 Earthquake Vulnerability Analysis
Earthquakes are a considerable threat to life and property in the City of Napa. A moderate to severe seismic incident on any fault zone in close proximity to the city can be expected to cause:
▪ Extensive property damage, particularly to pre-1930s unreinforced masonry structures; ▪ Possible fatalities and injuries;
▪ Damage to water and sewage systems;
▪ Disruption of communications systems;
▪ Broken gas mains and petroleum pipelines;
▪ Disruption of transportation arteries; and
▪ Competing requests for regional aid resources.
Community needs would quickly exceed the response capability of the city’s emergency management organization, requiring mutual assistance from volunteer and private agencies, the Governor's Office of Emergency Services, and the Federal Emergency Support Functions.
In an earthquake, the primary consideration is saving lives. Time and effort must also be given to providing for people's mental health by reuniting families, providing shelter to the displaced persons, and restoring basic needs and services. A major effort will be needed to remove debris and clear roadways, demolish unsafe structures, assist in reestablishing public services and utilities, and provide continuing care and temporary housing for affected citizens.
After an earthquake, there will be a loss of income both in private and public sectors. Individuals can lose wages due to businesses’ inability to function because of damaged goods or facilities. Due to business losses, the City of Napa will lose revenue. Economic recovery from even a minor earthquake is critical.
Earthquake Exposure
The exposure analysis for the City of Napa centers on an earthquake scenario produced from the West Napa fault line. As discussed in Section 4.5.4.5.1, this scenario presents the highest probability for a severe earthquake and severe shaking near the city.
An exposure analysis was conducted to develop earthquake vulnerability data throughout the City of Napa using the methods outlined in Section 4.3. To develop earthquake exposure data for the city, asset inventories for people, property, and critical facilities were superimposed with earthquake shaking intensity data from the USGS. Figure 4-32 depicts the exposure summaries for the West Napa fault line.
The summary demonstrates that 100 percent of the population would be exposed to very high or greater shaking.
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Figure 4-32: West Napa Exposure and Snapshot Map
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Population
Figure 4-33 and Table 4-37 summarize population exposure results for the West Napa earthquake scenario.
The entire population of the City of Napa is potentially exposed to direct and indirect impacts from earthquakes. The degree of exposure depends on many factors, including the age and construction type of dwellings, the soil types on which their homes are constructed, and proximity to fault location. Whether directly or indirectly impacted, the entire population will have to deal with the consequences of earthquakes to some degree. Business interruption could keep people from working, road closures could isolate populations, and loss of functions of utilities could impact populations that suffered no direct damage from an event itself.
Figure 4-33: Population Exposure to M6.7 West Napa Scenario Table 4-37: Population Exposure to M6.7 West Napa Scenario Total Population
City of Napa 79,722
Shake Severity Zone Population Count % of Total
X - Extreme - 0.00%
IX - Violent - 0.00%
VIII - Severe 65,968 82.75%
VII - Very Strong 13,754 17.25%
Total 79,722 100.00%
- -
65,968
13,754
-
10,000
20,000
30,000
40,000
50,000
60,000
70,000
X - Extreme IX - Violent VIII - Severe VII - Very Strong Population Exposure
Population Count by Exposure
to USGS 50-YR Shake Intensities
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Property and Building Ages
The vulnerability of buildings and structures to an earthquake depends on determining two important factors. The first is the year in which seismic codes were initially adopted and enforced by the jurisdiction having authority, and the second is the year in which seismic codes were improved and enforced. These are known as benchmark years, marking significant milestones in California Building Code requirements that directly affect the structural integrity of development in California. The city currently adheres to the 2019 California Building Code.
Table 4-38 provides a listing of code improvements. Benchmark years are indicated in bold. For reference, Table 4-39 provides the definitions of building types.
Table 4-38: Seismic Benchmark Years
Code Edition Effective Date Building Type
(2019 CBC) January 1, 2020
(2016 CBC) January 1, 2017
(2013 CBC) January 1, 2014 N/A
(2012 IBC)
(2010 CBC) January 1, 2011 N/A
(2009 IBC)
(2007 CBC) January 1, 2008 N/A
(2006 IBC)
(2001 CBC) November 1, 2002 N/A
(1997 UBC)
(1998 CBC) July 1, 1999 W1a, S2, S2a, RM1, PC1, PC1a
(1997 UBC)
(1994 UBC) January 7, 1996 S1, S1a, C1, C2, C2a, RM2
(1991 UBC) November 29, 1992 URM
(1988 UBC) April 29, 1990 S2 & S2a
(1985 UBC) November 8, 1987 N/A
(1982 UBC) December 9, 1984 N/A
(1979 UBC) June 21, 1981 N/A
(1976 UBC) November 1, 1977 W1 and W2
(1973 UBC) April 13, 1975 N/A
(1970 UBC) August 29, 1971 N/A
(1967 UBC) July 12, 1968 N/A
(1964 UBC) July 1, 1965 N/A
(1961 UBC) August 17, 1962 N/A
(1958 UBC) October 1, 1958 N/A
(1955 UBC) January 1, 1956 N/A
(1955 UBC) January 1, 1956 N/A
(1946 UBC) June 18, 1948 N/A
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Code Edition Effective Date Building Type
(1943 UBC) July 13, 1944 N/A
(1940 UBC) April 4, 1941 N/A
(1937 UBC) September 10, 1937 N/A
(1930 UBC) March 20, 1933 N/A
Source: ASCE 41-13. County Building Department
Table 4-39: Definitions of FEMA Building Types
FEMA Building Type Definition
W1 Wood Light Frame
W1A Wood Light Frame (multi-unit residence)
W2 Wood Frame (commercial and industrial)
S1 Steel Moment Frames
S2 Steel-braced Frames
S3 Steel Light Frames
S4 Steel Frames with concrete shear walls
S5 Steel Frames with infill masonry walls
C1 Concrete Moment Frames
C3 Concrete Frames with infill masonry shear walls
C2 Concrete Shear Walls
PC1 Tilt-Up Concrete shear walls
PC2 Precast Concrete Frames with shear walls
RM1 Reinforced Masonry Walls with flexible diaphragms
RM2 Reinforced Masonry Walls with stiff diaphragms
URM Unreinforced Masonry Bearing Walls
Soft-Story Buildings
A soft-story building is a multi-story building with one or more floors that are “soft” due to structural design.
If a building has a floor that is 70 percent less stiff than the floor above it, it is considered a soft-story building. These floors can be especially dangerous in earthquakes because they cannot cope with the lateral forces caused by the swaying of the building during an event. As a result, the soft story may fail, causing what is known as a soft-story collapse. Soft stories are typically associated with retail spaces and parking garages, often on the lower stories of a building. A soft-story collapse can cause the rest of the building to collapse as well, causing serious structural damage that may render the structure totally unusable.
Soft-story collapse is one of the leading causes of earthquake damage to private residences. The level of vulnerability due to this type of construction within the planning area is not currently known. This type of data should be generated to support future earthquake risk assessments. 1-26-2022 Submittal EXHIBIT A Page 162 of 416
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Property Value Exposure
An inventory of current market values and the content value was completed using County Assessor’s parcel data. GIS was used to create centroids, or points, to represent the center of each parcel polygon, assumed to be the location of the structure for analysis purposes. The centroids were then superimposed with the USGS probabilistic shaking severity zones to determine the at-risk structures. Table 4-40 shows the count of at-risk parcels and their associated building and content exposure values to the West Napa earthquake scenario.
Table 4-40: Parcel Exposure to M6.7 West Napa
Total
Parcels Total Market Value ($) Total Content Value ($) Total Value ($) City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Shake Severity Zone
Improved
Res. Parcel
Count
% of
Total
Market Value Exposure
($)
Content Value Exposure
($) Total Exposure ($) % of Total
X - Extreme - - - - - -
IX - Violent - - - - - -
VIII - Severe 28,857 80.2% $11,009,739,257 $8,154,372,715 $19,164,111,972 79.6% VII - Very Strong 7,113 19.8% $2,757,249,202 $2,145,131,663 $4,902,380,865 20.4% Total 35,970 100.0% $13,766,988,459 $10,299,504,378 $24,066,492,838 100.0% Critical Facilities and Infrastructure
Earthquakes pose numerous risks to critical facilities and infrastructure. Seismic risks, or losses, that are likely to result from exposure to seismic hazards include:
▪ Utility outages;
▪ Economic losses for repair and replacement of critical facilities, roads, buildings, etc.; ▪ Indirect economic losses, such as income, lost during downtime resulting from damage public infrastructure; and
▪ Roads or railroads that are blocked or damaged, preventing access throughout the area and isolating residents and emergency service providers needing to reach vulnerable populations or to make repairs.
Linear utilities and transportation routes are vulnerable to rupture and damage during and after a significant earthquake event. The cascading impact of a single failure can have effects across multiple systems and utility sectors. Degrading infrastructure systems and future large earthquakes with epicenters close to critical regional infrastructure could result in system outages that last weeks for the most reliable systems, and multiple months for others.
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All critical facilities in the City of Napa are exposed to the earthquake hazard. Table 4-41 lists the number of each type of facility in the Violent, Severe, and Very Severe MMI severity zones within the city, described in Table 4-34.
Table 4-41: Critical Facility Exposure to West Napa Scenario Critical Infrastructure - M6.7 West Napa
Infrastructure Type X - Extreme IX - Violent VIII - Severe VII - Very Strong Essential Facility**- - 7 -
Fire Station - - 5 -
Hospital - - 1 -
Police Station - - 1 -
High Potential Loss - - 269 53
Adult Residential Facility - - 6 1
Child Care Center - - 38 7
Church - - 50 4
Communication Tower - - 5 1
Dam - - - 2
Farm Worker Housing - - - -
Foster Family Agency - - 4 -
Historic Building - - 30 -
Home Care Organization - - 4 1
Library - - 3 -
*Real Property Asset - - 55 26
Residential Child Care - - 3 -
Residential Elder Care Facility - - 32 2
School - - 35 5
Stream Rain Gauges - - 4 3
Water Treatment Plant - - - 1
Transportation and Lifeline - - 161 49
Bridge - - 27 4
Power Plant - - 1 -
Pressure Regulator Station - - 16 3
Pump Station - - 3 4
Sample Station - - 110 31
Substation - - 1 -
Water Tank - - 3 7
Grand Total - - 437 102
* Real Property Assets are digitized insurance rolls for demonstrating value and ownership. **Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here.
HazMat Fixed Facilities
Earthquakes can produce hazardous materials (HazMat) threats at extremely high levels. Depending on the year of build and construction of each facility containing HazMat, the earthquake-initiated hazardous material release (EIHR) potential will vary. HazMat contained within masonry or concrete structures built before certain benchmark years may be particularly vulnerable. 1-26-2022 Submittal EXHIBIT A Page 164 of 416
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Utilities
Linear utilities and transportation infrastructure would likely suffer considerable damage in the event of an earthquake. Due to the amount of infrastructure and sensitivity of utility data, linear utilities are difficult to analyze without further investigating individual system components. Table 4-42 provides the best available linear utility data. It should be assumed that these systems are exposed to breakage and failure.
Table 4-42: Lifeline Exposure West Napa Scenario
Lifelines (miles) - M6.7 West Napa
Infrastructure Type (Linear) X - Extreme IX - Violent VIII - Severe VII - Very Strong Levee - - 0.4 1.7
Levee Centerline - - 1.2 -
Levee Flood Wall - - 0.6 0.3
NG Pipeline - - 19.2 0.6
Railroad - - 7.2 0.9
Street - - 230.5 54.1
Alley - - 0.2 -
Cul-de-sac - - 0.2 -
Driveway - - 1.2 0.9
Interstate - - 8.4 -
Local road - - 22.3 2.0
Local road, major - - 143.7 40.5
Primary highway - - 5.1 -
Ramp - - 6.8 0.2
Road, parking area - - 1.4 0.1
State/county highway - - 41.4 10.1
Thoroughfare, major - - - 0.3
Traffic circle - - - 0.1
Electric Transmission Line - - 6.5 5.4
Water Transmission Line - - 24.4 8.6
Grand Total - - 290.0 71.8
Water Supply Utilities
The City of Napa water supply is provided by three city-owned and operated treatment plants. These include Hennessey, Barwick-Jamieson terminal of the State Water Project, and Milliken. The Barwick Jamieson Canyon water treatment plant had major improvements expected to last 40 years completed in 2010, including the addition of ozone treatment, new conventional treatment basins, two new filters, as well as washwater recovery facilities. The facility capacity was increased from 12 million gallons per day (MGD) to 20 MGD. (City of Napa Hazard Mitigation Plan, 2015) 1-26-2022 Submittal EXHIBIT A Page 165 of 416
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Natural Gas Utilities
Natural gas and electric utilities, in the city’s case Pacific Gas and Electric (PG&E), are responsible for operating and maintaining natural gas infrastructure safely and efficiently, including facilities used to deliver gas to customers.
Damage to natural gas systems primarily results from damage on the customer side to the structures in which the systems are housed or damage to the equipment to which gas lines are connected. The shifting or toppling of gas appliances, such as water heaters or stoves, is the principal cause of post-earthquake fire ignitions that are gas-related; however, building collapse and deformation of structural components can also cause damage to interior gas piping. (California Seismic Safety Commission, 2002) In addition, utility natural gas systems can be damaged through ground displacements, including surface faulting, landslide-like movements, and soil failure or liquefaction produced by strong ground shaking.
However, this is mainly a concern for older pipelines that may be weakened by corrosion or were constructed using outdated methods and materials. Cast iron, aging bare steel pipe, and pipe with threaded connections are the most susceptible to damage from ground shaking. (Id.) Breaks in the system will affect large portions of the city, and restoration of natural gas service could be significantly delayed.
Earthquakes may impact natural gas safety in the following ways:
▪ Ground shaking generally leads to substantially more instances of building damage than fire ignitions.
▪ Building damage caused by substantial ground shaking is the most likely to impact utility and customer gas systems and lead to gas-related fire ignitions. ▪ Twenty percent to 50 percent of post-earthquake fire ignitions will be related to natural gas. ▪ Post-earthquake fire ignition consequences are largely financial for residential gas customers. A fire ignition only becomes a life safety concern when inhabitants are unable to exit the building following earthquakes. While experience in past earthquakes indicates that egress from earthquake-damaged single-family homes is generally possible, residents in larger multifamily units, especially on higher floors, may be at risk since they provide a greater chance for damaging the structure and trapping the occupants and greater difficulty evacuating. (Id.) Gas customers and City of Napa residents are responsible for using gas safely on their property by maintaining their gas appliances in good working condition, assuring that only qualified individuals are engaged to modify or maintain their gas service and facility piping, and knowing what to do before and after earthquakes to maintain the safe operation of their natural gas service.
The following conditions, when combined, pose the greatest risk for post-earthquake fire damage:
• Liquefaction;
• High wind and low humidity weather conditions;
• Dense vegetation that could catch fire;
• High building density;
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• Unoccupied buildings, as they post problems with mitigating damage to gas systems or control small fires; and
• Impaired communications, damage to water systems, numerous requests for assistance, direct damage to fire stations, restricted access because of traffic congestion and damaged roadways, and delays in mutual aid from neighboring fire districts, which can create delays in firefighting response. (Id.)
Telecommunication
Telecommunication systems will be affected by a system failure, overloads, loss of electrical power, and possible failure of some alternate power systems. Immediately following an event, numerous failures will occur, compounded by system use overloads. This will likely disable up to 80 percent of the telephone system for one day. County UHF/VHF and microwave radio systems are expected to operate at 40 percent effectiveness for the first 12 hours following an earthquake, increase to 50 percent effectiveness for the second 12-hour period, then begin to slowly decline to approximately 40 percent effectiveness within 36 hours. (City and County of San Francisco Hazard Mitigation Plan, 2014) Microwave systems will likely be 30 percent or less effective following a major earthquake.
Public Schools
The Field Act was enacted on April 10, 1933, one month after the Long Beach Earthquake in which many schools were destroyed or suffered major damage. Since then, public school construction has been governed by the Act and enforced by the Division of the State Architect (DSA). In any community, public schools constructed under the Field Act after 1978 are likely to be among the safest buildings in which to experience a major earthquake. The Field Act requires:
• School building construction plans to be prepared by qualified California licensed structural engineers and architects.
• Designs and plans to be checked by the DSA for compliance with the Field Act before a contract for construction can be awarded.
• Qualified inspectors, independent of the contractors and hired by the school districts, to continuously inspect construction and verify full compliance with plans. • The responsible architects and structural engineers to observe the construction periodically and prepare changes to plans, if needed, subject to approval by DSA. • Architects, engineers, inspectors, and contractors to file reports, under penalty of perjury, to verify compliance of the construction with the approved plans emphasizing the importance of testing and inspections to achieve seismically safe construction. Any person who violates the provisions or makes any false statement in any verification report or affidavit required pursuant to the Act is guilty of a felony. (Seismic Safety Commission, 2009)
Private schools are not subject to the Field Act and fall solely under the jurisdiction of the local building departments and building code requirements. Private schools are covered under the Private Schools 1-26-2022 Submittal EXHIBIT A Page 167 of 416
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Building Act of 1986, with the legislative intent that children attending private schools be afforded life safety protection similar to that of children attending public schools. (Id.) In the late 1960s, regulations were put in place to have pre-Field Act (1933) buildings retrofitted, removed from school use, or demolished. (Cal. Edu. Code § 15516, Appendix X, 1968) The Field Act also prohibits the use of unreinforced masonry buildings as school buildings. Seismic building standards, in general, were greatly strengthened after significant damage to buildings was observed, especially in the 1971 San Fernando earthquake. The Field Act regulations in place since 1978 are considered adequate for public school buildings in most cases. (Id.)
Transportation
Earthquake events can significantly impact bridges and overpasses, which often provide the only access to some neighborhoods. Since soft soil regions generally follow floodplain boundaries, bridges that cross watercourses are considered vulnerable.
There are four highways which traverse the City of Napa. Highways 29 and 121 run generally north-south through the city while Highway 12 runs east-west and intersects with Interstate 80 approximately seven miles to the east. Highway 221 also extends south of Imola to the southern city limits. Table 4-42 shows transportation infrastructure exposed to shake severity zones in the event of the West Napa scenario.
Earthquake Damage Estimation
Hazus Earthquake damage data was generated using a Level 2 Hazus 4.2 analysis. Hazus is a FEMA software product that uses a GIS to analyze multiple factors influencing earthquake damage estimates, including peak ground velocity (PGV), peak ground acceleration (PGA), and soil types based on a given scenario and geographic area. Once the location and size of a hypothetical earthquake is identified, Hazus software estimates the intensity of the ground shaking, number of buildings damaged, number of casualties, damage to transportation systems and utilities, number of people displaced from their homes, and cost of repair and clean up.
The parcel data defined in Section 4.3 was imported into Hazus as User Defined Facilities (UDF) serving as the basis for replacement and content cost, as well as associated damage estimation and loss. The scenario used for the City of Napa Hazus analysis was the West Napa fault scenario.
Building damage outputs from Hazus are categorized into slight, moderate, and extensive damage. Ranges of damage are used to provide the user with an understanding of the building’s physical condition. Table 4-43 provides a physical description of each damage state.
County assessor data does not include detailed information for tax-exempt structures, such as federal and local government buildings. This data was added through the development of GIS data by utilizing insurance schedule tables for the city’s insured assets. 1-26-2022 Submittal EXHIBIT A Page 168 of 416
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While there are several limitations to the FEMA Hazus earthquake models, it does allow for potential loss estimation for each building construction category. Citywide loss estimation results are summarized by building category type in Table 4-45 for West Napa 6.7 magnitude earthquake scenario. It is important to understand that the Hazus loss estimation values for earthquakes are categorized in exceedance values.
From reviewing Table 4-45, one can infer the probability of structures exceeding extensive damage is relatively low. However, if damage were to occur, the economic loss is averaged and summarized for each building type defined in the software.
Important to note: Loss estimation is the worst-case scenario. Loss estimation does not include damage to transportation routes, infrastructure, and other public and private utilities located throughout the city.
An important concept in loss data is the “probability” of damage to exceed a certain degree. It is unlikely that buildings in city would receive “extensive” damage from earthquake shaking.
Table 4-43: Hazus Building Damage Descriptions
Damage
State Damage Description
Slight Small plaster cracks at corners of door and window openings and wall/ceiling intersections; small cracks in masonry chimneys and masonry veneers. Small cracks are assumed to be visible with a maximum width of less than 1/8 inch (cracks wider than 1/8 inch are referred to as “large” cracks).
Moderate Large plaster or gypsum-board cracks at corners of door and window openings; small diagonal cracks across shear wall panels exhibited by small cracks in stucco and gypsum wall panels; large cracks in brick chimneys; toppling of tall masonry chimneys.
Extensive Large diagonal cracks across shear wall panels or large cracks at plywood joints; permanent lateral movement of floors and roof; toppling of most brick chimneys; cracks in foundations; splitting of wood sill plates and/or slippage of structure over foundations.
Complete Structure may have large permanent lateral displacement or be in imminent danger of collapse due to cripple wall failure or failure of the lateral load resisting system; some structures may slip and fall off the foundation; large foundation cracks. Three percent of the total area of buildings with complete damage is expected to be collapsed, on average. 1-26-2022 Submittal EXHIBIT A Page 169 of 416
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Damage Estimation Improved Parcel and Government Property Loss Hazus 4.2 was used to estimate the loss potential to residential properties and government service facilities exposed to the M6.7 West Napa earthquake scenario. Hazus reports the damage potential and loss potential from a given earthquake scenario in four categories: slight damage, moderate damage, extensive damage, and economic loss. Economic loss consists of estimations on the cost of repair and replacement to damaged or destroyed buildings and contents, relocation expenses, capital-related income, wage losses, and rental income losses. The results shown in Table 4-44 summarize improved parcels and government property loss.
Table 4-44: Damage Estimations for M6.7 West Napa Scenario Building Type
Average of
Potential
Damage to
Exceed “Slight”
Average of
Potential
Damage to
Exceed
“Moderate”
Average of
Potential
Damage to
Exceed
“Extensive”
Average
Economic Loss
for Each Building
Category
Sum of
Economic Loss
Proportion of
Loss (%)
Agriculture 88% 71% 35% $113,145 $28,512,628 1%
Commercial 60% 21% 3% $61,838 $748,177,010 37%
Education 0% 0% 0% $0 $0 0%
Emergency 63% 38% 13% $514,054 $4,112,429 0%
Government 65% 36% 12% $270,787 $23,558,467 1%
Industrial 85% 64% 26% $307,226 $180,034,674 9%
Religion 0% 0% 0% $0 $0 0%
Residential 63% 27% 6% $45,639 $1,051,054,768 52%
Total $2,035,449,977
Note: Total Inventory Values
1 - Building Replacement Costs = $13,885,314,683
2 - Content Replacement Costs = $10,307,648,380
3 -Total Value = $24,192,963,063
Damage Estimation for City-Owned Property
Hazus 4.2 was also used to estimate the loss potential to city facilities exposed to the West Napa M6.7 earthquake scenario. City insurance data was obtained and formatted for use in Hazus for a detailed damage estimation. This dataset has additional information, including number of floors, building value, content value, and construction type, that greatly enhances results from the default Hazus database. The results shown in Table 4-45 summarize essential facility and high potential loss facilities using insurance holding data.
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Table 4-45: Damage Estimations for M6.7 West Napa Scenario Site Value Probability Damage Exceeds
Building/
Site Name # Bldg. Structure Content Total Slight Moderate Extensive Economic
Loss
Loss
Pct.
Corp Yard 2 $61,508 $2 $61,510 52% 20% 1% $7,183 12%
Equipment 5 $295,985 $34,711 $330,696 78% 58% 29% $98,850 30% Fire 7 $13,271,585 $1,213,351 $14,484,936 66% 39% 14% $3,358,561 23% Library 1 $2,602,390 $57,841 $2,660,231 86% 76% 46% $1,355,273 51% Misc 9 $10,014,577 $1,492,133 $11,506,710 63% 29% 5% $1,568,788 14% Storage 2 $95,596 $72,156 $167,752 64% 41% 14% $33,344 20% Water 18 $43,064,168 $1,559,208 $44,623,376 55% 30% 10% $10,333,406 23% Office 7 $4,897,252 $860,428 $5,757,680 60% 26% 8% $469,128 8% Restroom 4 $399,840 $4 $399,844 67% 35% 13% $72,266 18% Golf Course 3 $1,714,926 $3 $1,714,929 90% 71% 33% $623,547 36% Rec 1 $403,524 $28,901 $432,425 60% 24% 4% $60,395 14%
Residence 18 $5,695,965 $77,678 $5,773,643 70% 34% 7% $1,138,158 20% Child Care 1 $235,785 $1 $235,786 50% 21% 3% $28,768 12% City Hall 1 $4,183,540 $1,408,420 $5,591,960 87% 75% 36% $1,991,072 36% Police 2 $6,228,921 $1,408,421 $7,637,342 48% 19% 2% $759,991 10% Communic
ation Tower 1 $70,427 $14,085 $84,512 86% 76% 46% $36,677 43% Parking
Garage 3 $17,747,440 $3 $17,747,443 55% 24% 3% $2,467,117 14% Historic 1 $2,184,260 $1 $2,184,261 95% 90% 62% $1,444,036 66% Museum 1 $850,108 $1 $850,109 78% 65% 34% $358,669 42%
Lot 2 $890,987 $281,686 $1,172,673 71% 47% 20% $375,916 32% Teen Center 1 $184,741 $28,169 $212,910 39% 14% 1% $16,058 8% Shop 4 $2,585,021 $422,049 $3,007,070 58% 26% 8% $868,442 29% Community
Center 1 $1,996,030 $70,421 $2,066,451 57% 14% 1% $205,252 10% Grand Total 95 $119,674,576 $9,029,673 $128,704,249 65% 36% 12% $27,670,895 21%
4.5.4.10 Future Trends in Development
Land use in the planning area will be directed by The City of Napa’s General Plan adopted under California’s General Planning Law. The Safety Element of the General Plan establishes standards and plans for the protection of the community from hazards. The information in this plan provides a tool to ensure that there is no increase in exposure in areas of high seismic risk. Development in the planning area will be regulated through building standards and performance measures so that the degree of risk will be reduced. 1-26-2022 Submittal EXHIBIT A Page 171 of 416
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The geologic hazard portions of the planning area are heavily regulated under California’s General Planning Law. The California Building Code establishes provisions to address seismic risk.
4.5.4.11 Earthquake Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and earthquake hazard data.
Earthquake problem statements for the City of Napa are listed in Table 4-46.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. See Table 5-6 for a full list of mitigation actions and the corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-46 and Table 5-6.
Table 4-46: Earthquake Problem Statements
Problem No. Hazard Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-EQ-CN-5 Earthquake Impact PPRO - Property
Protection
The following critical facilities are located in
a severe shake zone for the 6.7 west napa
earthquake scenario: 33 schools, 32
residential elder care facilities, 30 historic
buildings, 27 bridges, and 26 family child
care homes
ma-EQ-CN-18,
ma-EQ-CN-19,
ma-EQ-CN-18
ps-EQ-CN-6 Earthquake Impact SP - Structural
Projects
Redundancy in the City's water system is
needed to make it more resilient to the
impacts of an earthquake.
ma-EQ-CN-20
ps-EQ-CN-7 Earthquake Impact PE&A - Public
Education &
Awareness
Mobile home parks are particularly
vulnerable to the impacts of an earthquake.
ma-EQ-CN-17,
ma-EQ-CN-56
ps-EQ-CN-8 Earthquake Impact SP - Structural
Projects
Building retrofits are needed on historic
structures in downtown.
ma-EQ-CN-56,
ma-AH-CN-5,
ma-AH-CN-8,
ma-AH-CN-9
ps-EQ-CN-9 Earthquake Impact SP - Structural
Projects
Backup power generation is needed to
support the City as a whole
ma-AH-CN-57
ps-EQ-CN-10 Earthquake Victim PE&A - Public
Education &
Awareness
79,722 people live in a severe shake zone for
the 6.7 west napa earthquake scenario
ma-EQ-CN-19,
ma-AH-CN-3,
ma-EQ-CN-17,
ma-EQ-CN-19,
ma-AH-CN-57
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4.5.5 Pandemic Disease Hazard Profile
The U.S. Centers for Disease Control and Prevention defines a disease outbreak as the occurrence of more cases of disease than normally expected within a specific place or group of people over a given period of time. An epidemic is a localized outbreak that spreads rapidly and affects many people or animals in a community.
A pandemic is an epidemic that occurs worldwide or over an exceptionally large area and affects a large number of people or animals. Pandemics are profiled here in accordance with their mitigation measures, which focus on physical parameters for mitigation rather than operational parameters focused on response efforts.
Pandemics are hazards which have sustained durations. Although the daily impacts may be low, cumulative impacts are likely to be overwhelming for both the health system and the community. During a moderate pandemic, the City of Napa could see a sustained increase in intensive care unit and emergency department admissions, patients needing to be placed in isolation, and in deaths. The capacity to provide medical care will be reduced, including basic emergency medical system (EMS) response, hospital emergency department services, and isolation rooms. At the same time, a higher than usual absenteeism rate for all employees is expected.
The following are the most prevalent types of pandemic diseases anticipated in the planning area:
Coronavirus(COVID-19)
Coronavirus is a large family of viruses that cause illness ranging from the common cold to more severe diseases such as the Middle East Respiratory Syndrome and Severe Acute Respiratory Syndrome. SARS-CoV-2, which causes the disease COVID-19, is a new strain of these viruses which has not been previously identified in humans. The virus is spread easily between people, primarily by close contact from person-to-person through inhalation of the virus or contact with mucous membranes. It can be contracted through respiratory droplets produced from the cough, sneeze, or vocalization of an infected person, and evidence suggests it spreads more efficiently than influenza, but not as easily as the measles. (CDC, 2021) COVID-19, short for "coronavirus disease 2019," is the most recent pandemic declared by the World Health Organization and is still active in 2021. COVID-19 is discussed in more detail herein.
Influenza Virus
Influenza viruses, commonly and collectively referred to as “the flu,” can cause mild to severe illness, and at times can lead to death. Anyone can get sick with the flu, but some people are at a higher risk of flu-related complications if they get sick. This includes older and younger people and people with certain chronic medical conditions.
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West Nile Virus
The West Nile virus is a mosquito-borne virus that is common in Africa, west Asia, the Middle East, and more recently, North America. Human infection with West Nile virus may result in serious illness. Experts believe West Nile is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall.
Hepatitis C
Hepatitis C is a liver disease caused by the Hepatitis C virus, which is found in the blood of persons who have this disease. Hepatitis C virus is spread by contact with the blood of an infected person.
Lyme Disease
Lyme disease is an infectious disease caused by a bacterium known as Borrelia burgdorferi. People are most often infected with Lyme through the bite of infected ticks. Lyme disease was first recognized in the northeastern United States in the 1970s and has been reported in many areas of the country since, including California. Typical Lyme disease symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans, often identified by its “bull’s-eye” appearance. If left untreated, the infection can spread to joints, the heart, and the nervous system. (CDC, 2020)
Measles
Measles, also called rubeola, is a childhood infection caused by a paramyxovirus of the genus Morbillivirus. Once so common that nearly all children got measles by the time they were 15 years of age, the virus can now almost always be prevented with a vaccine. (CDC, n.d.) While death rates have been falling worldwide as more children receive the measles vaccine, the disease can be serious and even fatal for small children and still kills more than 100,000 people a year, most under the age of five. As a result of high vaccination rates in general, measles was declared eliminated in the United States in 2000. However, the number of cases per year has increased between 2004 and 2014 from 30 to 600 a year, respectively, primarily occurring in unvaccinated people or originating from outside the United States. (Mayo Clinic, n.d.)
Rabies
Rabies is a viral infection transmitted in the saliva of infected mammals. Common modes of rabies virus transmissions are through bites, scratches, and other forms of contact with the saliva of an infected host, often a bat, raccoon, or skunk in the Unites States but most commonly dogs worldwide. Other various routes of transmission include contamination of mucous membranes, aerosol transmission, and corneal transplantations. Any penetration of the skin by teeth, regardless of location, represents a potential risk of rabies transmission. The rabies virus infects the brain and central nervous system, causing encephalopathy and, ultimately, death if left 1-26-2022 Submittal EXHIBIT A Page 174 of 416
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untreated before symptoms occur. Symptoms include fever, headache, excess salivation, muscle spasms, paralysis, and mental confusion.
4.5.5.1 Policies, Plans, and Regulatory Environment
United States Department of Health and Human Services
The U.S. Department of Health and Human Services has statutory responsibility for preventing the introduction, transmission, and spread of communicable diseases in the United States. The Centers for Disease Control and Prevention (CDC) is housed within the Department of Health and Human Services and is responsible for controlling the introduction and spread of infectious diseases. The CDC’s roles include:
▪ Instituting public education and awareness related to disease spread and prevention; ▪ Studying and tracking transmission rates, treatment options, and vaccines; ▪ Maintaining active surveillance of diseases through investigation and data collection, analysis, and distribution;
▪ Developing and implementing operational programs and guidance relating to environmental health problems;
▪ Conducting research aimed at developing and testing effective disease prevention and control; and
▪ Implementing a program to sustain a strong national workforce in disease prevention and control and a national program for improving the performance of clinical laboratories. (CDC, 2020) The Division of Global Migration and Quarantine works to control disease transmission internationally through the operation of Quarantine Stations at ports of entry, establishment of standards for medical examination of persons destined for the United States, and administration of interstate and foreign quarantine regulations, which govern the international and interstate movement of persons, animals, and cargo.
California Department of Public Health
The California Department of Public Health (CDHP) is responsible for protecting public health within the state of California. The CDPH is comprised of public health professionals, researchers, scientists, doctors, nurses, and other staff members who aid in implementing the organization’s programs and services. The essential functions of the CDHP are comprehensive in scope and include infectious disease control and prevention, food safety, environmental health, laboratory services, patient safety, emergency preparedness, chronic disease prevention, and health promotion. Promoting family health and health equity, and keeping vital records and statistics are also functions of the CDPH.
Napa County Mosquito Abatement District
The Napa County Mosquito Abatement District (NCMAD) has been controlling mosquito populations for the residents of Napa County since 1925. The Board of Trustees governs the district and is comprised of representatives from each incorporated city and Napa County. There are currently eight employees who are responsible for controlling mosquitoes throughout the county. 1-26-2022 Submittal EXHIBIT A Page 175 of 416
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NCMAD works closely with other public agencies, park districts, and wineries to provide an effective and environmentally sound mosquito control program. The district also works with planning agencies to minimize mosquito production in wetland restoration and enhancement projects.
4.5.5.2 Past Events
There have been six pandemics since 1900. The previous pandemics occurred in 1918-1920, 1957-1958, 1968- 1969, 1977-1978, 2009-2010, and 2019-present. The 1918 Pandemic, occurring between 1918 and 1920 and commonly referred to as the Spanish Flu, was unusually severe and had an extensive mortality rate. It is estimated that the 1918 Pandemic killed as much as one percent of the world’s population, or 40,000,000 people worldwide, including more than 500,000 in the United States. More recently, the H1N1 Pandemic in 2009 resulted in 482,000 laboratory-confirmed cases and 6,071 deaths. (Centers for Disease Control and Prevention, 2019)
Coronavirus disease 2019 (COVID-19) is an ongoing pandemic. It was first detected in Wuhan City, China in late December of 2019 and was later declared a Public Health Emergency of International Concern on January 30, 2020. COVID-19 is currently ongoing and has resulted in more than 270 million globallyconfirmed cases, and more than 5 million global deaths as of December 2021. (Johns Hopkins University of Medicine, 2021) The pandemic has also led to a severe global economic recession and financial and corporate sector distress. It is currently unclear how long or how severe this pandemic and related contraction in economic activity will be. The following facts capture a snapshot of the ongoing COVID-19 pandemic in Napa County as of December 1, 2021:
▪ More than 14,000 cases of COVID-19 have been reported in Napa County since the start of the pandemic.
▪ To date, peak number of cases per month were in December 2020 and January 2021, with 2,600 and 2,500 cases reported each respective month.
▪ On April 15, 2021, vaccines for COVID-19 became available in California for everyone aged 16 and older. As of December 7, 2021, 71% of Napa County’s population is fully vaccinated. (Napa County, 2021)
Table 4-47 represents the number of select cases of communicable diseases which have occurred per year in Napa County. This table prioritizes vaccine-preventable diseases for which there is existing data for Napa County. Cases of Whooping Cough (Pertussis) and Hepatitis A are the highest of the 11 categories. 1-26-2022 Submittal EXHIBIT A Page 176 of 416
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Table 4-47: Napa County Vaccine Preventable Disease Cases 2001-2018 Vaccine Preventable Disease 2001-2018 2010-2018 2011-2018 Diphtheria 0
Hepatitis A 12
Hepatitis B, Acute 1
Hepatitis C, Acute 0
Invasive Meningococcal Disease 7
Measles 3
Mumps 2
Pertussis 312
Rubella 0
Tetanus 0
Varicella Hospitalizations 1
Source: Immunization Branch, California Department of Public Health Note: Case counts were reflected in the dataset in three distinct periods which cumulatively span a 2001-2018 date range.
4.5.5.3 Location
The entire planning area is susceptible to the human health hazards discussed in this profile. Some hazards, such as West Nile virus, can have a geographic presence within the planning area. Others may be transported into the county through residents and visitors who travel extensively. As of December 1, 2021, a total of 8,315 cases have been confirmed in the City of Napa. Napa City and County Public Health have been working closely with local health care providers, the California Department of Public Health, and with the CDC to closely monitor the virus. (Napa County, 2021)
4.5.5.4 Frequency and Probability of Future Occurrences The San Francisco Bay Area has a high probability of a naturally-occurring, mild to moderate pandemic.
People in the Bay Area travel internationally more often and come into contact with many people on a daily basis. (San Francisco Department of Emergency Management, 2019) Influenza Virus: According to the CDC, influenza has a predictable pattern and a near certainty of occurrence. CDC estimated that approximately 5 to 20 percent of the population contracts the seasonal flu. With the introduction of influenza vaccination, influenza occurrences are likely to remain below those reported during the particularly-high 2009 to 2010 influenza season. (Center for Disease Control and Prevention, 2020)
Coronavirus (COVID-19): A report released by the World Health Organization and the China Joint Commission found that transmission rates of COVID-19 vary based on location. In general, between one and five percent of people in contact with a confirmed case of the virus subsequently become a laboratory-confirmed case of COVID-19. (World Health Organization-China Joint Mission, 2020) However, evidence suggests some new variants of SARS-CoV-2, such as the Delta variant, may be 1-26-2022 Submittal EXHIBIT A Page 177 of 416
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more infectious and cause increased transmissibility compared to other variants or the original strain. (CDC, 2021)
West Nile Virus: In California, mosquitoes are monitored and controlled primarily to reduce cases of West Nile virus, malaria, encephalitis, dog heartworm, and sensitivity to bites. Human mosquitoborne diseases, including West Nile, have declined significantly in California since the creation of mosquito and vector control agencies.
Lyme Disease: There have been 45 confirmed cases of Lyme disease in Napa County between 2001- 2018. (California Department of Public Health) Cases are expected to continue to develop, and instances may increase with warming temperatures due to climate change.
The frequency and probability of other diseases discussed in this profile are unpredictable and contingent on factors such as public awareness, treatment options, and vaccination rates.
4.5.5.5 Severity and Extent
A communicable disease can affect many people, causing mild illness, hospitalization, or in some cases, death. Predicting severity and extent for communicable disease transmission can be difficult and is predicted by modeling scenarios based on a number of factors.
The CDC and the Office of the Assistant Secretary for Preparedness and Response developed five COVID19 Pandemic planning scenarios that attempt to predict transmission rates. These scenarios are based on data received by the CDC prior to March 2021. Scenarios 1 through 4 are based on parameter values that represent the lower and upper bounds of disease severity and viral transmissibility (moderate to very high). Scenario 5 represents the current best estimate about viral transmission and disease severity in the United States. (CDC, 2021)
Viral transmissibility is the average number of people that one infected person is likely to infect in a population without any immunity. The current best estimate for viral transmissibility for COVID-19 is 2.5 persons. Table 4-48 depicts the viral transmissibility rate values for each of the five planning scenarios (row 1). The Table also lists an Infection Fatality Ratio for each scenario (row 2). The Infection Fatality Ration is the number of individuals who die from the disease among all infected individuals (both symptomatic and asymptomatic). Rows 3-5 estimate the percentage of infections that will bear various characteristics. The CDC makes clear that the scenarios are intended to aid in public health preparedness and planning; they are not predictions or estimates of the expected impact of COVID-19. The CDC will update and augment these values as more is learned about the epidemiology of COVID-19. (CDC, 2021) 1-26-2022 Submittal EXHIBIT A Page 178 of 416
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Table 4-48: Parameter Values Contingent on Five COVID-19 Pandemic Planning Scenarios Parameter Scenario 1 Scenario 2 Scenario 3 Scenario 4
Scenario 5:
Current Best
Estimate
Viral Transmissibility Rate 2.0 4.0 2.5
Infection fatality ratio
(Estimated number of deaths
per 1,000,000 infections)
0–17 years old: 6
18–49 years old: 150
50–64 years old: 1,800
65+ years old: 26,000
0–17 years old: 80
18–49 years old: 1,700
50–64 years old: 20,000
65+ years old: 270,000
0–17 years old: 20
18–49 years old: 500
50–64 years old: 6,000
65+ years old: 90,000
Percent of Infections that are
Asymptomatic 15% 70% 15% 70% 30%
Infectiousness of
Asymptomatic Individuals
Relative to Symptomatic
25% 100% 25% 100% 75%
Percentage of Transmission
Occurring Prior to Symptom
Onset 30% 70% 30% 70% 50%
Source: Centers for Disease Control and Prevention, COVID-19 Pandemic Planning Scenarios (2021)
4.5.5.6 Secondary Hazards
Human health hazards are not like other natural hazards such as earthquakes, floods, or fires that have measurable secondary impacts. This is due primarily to the fact that human health hazards do not impact general building stock or critical facilities and infrastructure as other hazards do. The largest secondary impact caused by human health hazards would be economic. Large outbreaks of any human health hazard could reduce the workforce significantly for long periods of time while the infected population recovers from the impacts of the disease. Hospitals and health care providers could also be overwhelmed, reducing capacity to treat day-to-day patients, even for minor illness or injuries, or to perform non-emergency or elective procedures.
Moreover, as the ongoing COVID-19 outbreak is revealing, a pandemic can add significant challenges to hazard mitigation efforts, not to mention complicating response efforts for other natural hazard events. In 2020, the U.S. Forest Service suspended controlled burns scheduled in the spring due to the COVID-19 Pandemic. (Groom, 2020) FEMA also released guidance on COVID-19 wildfire response in June of 2020. (U.S. Fire Administration, 2020) Many populations vulnerable to COVID-19 are also most vulnerable to the effects of smoke inhalation. (Hu, 2020)
This is an emerging issue, and developments and guidance changes as new data arises. Mitigating the impacts of the pandemic, in many instances, means mitigating the impacts of a pandemic to other hazards that could occur simultaneously.
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4.5.5.7 Pandemic Disease Vulnerability Assessment
Population
All citizens in the City of Napa planning area could be susceptible to the human health hazards discussed in this profile. Additional pandemics or outbreaks of a communicable disease could have devastating effects on the population. The introduction of a disease, such as the plague or influenza, could rapidly impact those most at-risk (children, the elderly, and those already affected by health issues).
As discussed above, many populations vulnerable to COVID-19 are also most vulnerable to the effects of smoke inhalation. The same is true in reverse. A 2021 study found that the inhalation of fine particulate air pollution (PM2.5) from wildfire smoke during the summer of 2020 may have contributed to thousands of deaths from COVID-19 in the Western United States, especially in California, Oregon, and Washington. (Harvard School of Public Health, 2021)
Property
None of the health hazards addressed in this profile are considered to have any measurable impact on the built environment in the planning area. Economic impacts are expected during a pandemic, as is currently being experienced during the COVID-19 Pandemic.
Critical Facilities and Infrastructure
None of the health hazards addressed in this profile are considered to have any measurable impact on critical facilities in the planning area. However, healthcare facilities (and veterinary clinics) are prepared for pandemic disease hazards. Emergency management planning incorporates all disciplines responding to an event, including fire agencies, law enforcement, first responder ground and air ambulance agencies, public health, and mental and spiritual health. Planning includes identifying shelters, alternate treatment facilities, isolation capacity, and methods to immediately expand physical and human resources.
4.5.5.8 Future Trends in Development
The economic impact of a human health hazard could be localized to a single population or could be significant and widespread, depending on the number of cases and available resources to care for those affected. Other financial impacts are absorbed or managed by the organizations affected. For example, healthcare facilities and veterinary offices train their personnel at their own cost. When more people visit the City of Napa or move into the area, the potential for a pandemic outbreak rises and the resulting impacts can also increase. In particular, urban areas become more vulnerable as population density increases causing illnesses or contamination to spread more rapidly. 1-26-2022 Submittal EXHIBIT A Page 180 of 416
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4.5.5.9 Pandemic Disease Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing pandemic disease data. Pandemic disease hazard problem statements for the City of Napa are listed in Table 4-49.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. Projects or actions have been developed to mitigate each problem identified. See Table 5-6 for a full list of mitigation actions and corresponding problem statements that they address. Each problem statement is coded with a problem number for cross-referencing Table 4-49 and Table 5-6.
Table 4-49: Pandemic Disease Problem Statements
Problem No. Hazard Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-PN-CN-45 Pandemic Impact PRV - Prevention ,
SP - Structural
Projects
Utilities and critical facilities may not have
adequate fresh air/ ventilation to be
appropriate for essential work during
pandemic; essential works need sheltering
options to remain isolated during shifts
during pandemic.
ma-PN-CN-60
ps-PN-CN-46 Pandemic Victim PRV - Prevention ,
ES - Emergency
Services
COVID-19 variants pose a future risk to the
entire population of the City of Napa,
especially among unvaccinated residents
and those with existing risk factors.
ma-PN-CN-31,
ma-PN-CN-32,
ma-AH-CN-2
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4.5.6 Flood Hazard Profile
Flooding is one of the three primary hazards in California, along with earthquake and wildfire, and represents the second most destructive source of hazard, vulnerability, and risk statewide. (Cal OES, 2018) Flooding is a priority hazard for the City of Napa as well, and this HMP functions as the city’s floodplain management plan under FEMA’s Community Rating System (CRS), described in more detail in this section.
Connections between a river and its floodplain are most apparent during and after major flood events. A floodplain is the area adjacent to a river, creek, or lake that becomes inundated during a flood. Floodplains may be broad, as when a river crosses an extensive flat landscape, or narrow, as when a river is confined in a canyon. These areas form a complex physical and biological system that supports a variety of natural resources and provides natural flood and erosion control. When a river is separated from its floodplain with levees and other flood control facilities, its natural, built-in benefits can be lost, altered, or significantly reduced. (FEMA, 2020)
There are four types of flood events that might occur within the City of Napa area: riverine, flash, urban stormwater, and dam failure. Regardless of the type, the cause is primarily the result of extreme weather and excessive rainfall, either in the flood area or in an upstream reach. (The National Severe Storms Laboratory, 2020)
Riverine flooding, the most common type of flood event, occurs when a watercourse exceeds its bank-full capacity. Riverine flooding occurs as a result of prolonged rainfall that is combined with saturated soils from previous rain events, or combined with snowmelt, and is characterized by high peak flows of moderate duration and by a large volume of runoff. Riverine flooding occurs in river systems whose tributaries drain large geographic areas and can include many watersheds and sub-watersheds. The duration of riverine floods varies from a few hours to many days. Factors that directly affect the amount of flood runoff include precipitation amount, intensity and distribution, soil moisture content, channel capacity, seasonal variation in vegetation, snow depth, and water-resistance of the surface due to urbanization. (Id.) In the City of Napa, riverine flooding can occur anytime during the period from November through April. Flooding is more severe when antecedent rainfall has resulted in saturated ground conditions.
The term “flash flood” describes localized floods of great volume and short duration, generally in less than four hours. In contrast to riverine flooding, this type of flood usually results from a heavy rainfall in a relatively small drainage area. Precipitation of this sort usually occurs in the spring and summer. (Id.) Dam failures can also result from flash flooding. Dam failures are discussed separately in Section 4.5.1.
Urbanization may increase peak flow runoff as well as the total volume of stormwater runoff from a site, causing urban stormwater flooding. The increase is dependent upon the type of soil and topography in relation to the development, especially impervious surfaces like parking lots. Comparison of the peak flow 1-26-2022 Submittal EXHIBIT A Page 183 of 416
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and volume impacts to the watershed should be analyzed whenever development is proposed to assure that any increases are accommodated. (USGS, 2016)
Flooding may be a secondary impact from an earthquake, which may cause failure of dams, canal banks, or landslides that block drainage channels, streams, or rivers. See Section 4.5.4 for the Earthquake Hazard Profile.
Floodplain Definitions
100-YR Floodplain
The boundaries of the 100-year (100-YR) floodplain coincide with an annual risk of one percent and are a FEMA study product consisting of both floodway and flood fringe. 500-YR Floodplain
The boundaries of the 500-year (500-YR) floodplain coincide with an annual risk of 0.2 percent and are also a FEMA study product. The 500-YR floodplain includes the 100-YR.
Floodway
This includes the channel of the tributary and the land adjacent to it. This zone needs to remain free from obstruction so the 100-YR flood can be conveyed downstream.
Flood Fringe
This is the remaining portion of the 100-YR floodplain, excluding the floodway. This zone can be obstructed or developed if certain criteria are met.
Special Flood Hazard Area (SFHA)
An area having special flood, mudflow, or flood-related erosion hazards and shown on a Flood Insurance Rate Map (FIRM). The SFHA is the area where the National Flood Insurance Program’s (NFIP) floodplain management regulations must be enforced.
Floodplain Ecosystems
Floodplains can support ecosystems that are rich in quantity and diversity of plant and animal species. A floodplain can contain 100 or even 1,000 times as many species as a river. Wetting of the floodplain soil releases an immediate surge of nutrients left over from the last flood and resulting from the rapid decomposition of organic matter that had accumulated. Microscopic organisms thrive, and larger species enter a rapid breeding cycle. Opportunistic feeders, particularly birds, move in to take advantage. The production of nutrients peaks and falls away quickly; however, the surge of new growth endures for some time. This makes floodplains particularly valuable for agriculture. Species growing in floodplains are markedly different from those that grow outside floodplains. For instance, trees in floodplains and riparian areas tend to be very tolerant of root disturbance and very quick-growing compared to non-riparian trees.
Floodplains that are undisturbed or have been restored to a natural state provide many benefits to both human and natural systems. In their natural vegetative state, undisturbed floodplains provide the following benefits:
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▪ Slow the rate at which incoming surface runoff reaches the main body of water, slowing down the impact of flood events.
▪ Maintain water quality by allowing surface runoff to drop sediment into the natural soil, preventing it from depositing in streams and rivers.
▪ Recharge groundwater. The slowing of runoff allows additional time for the runoff to recharge existing groundwater aquifers.
▪ Provide habitat for large and diverse populations of plants and animals.
Floodplains are often compromised by human development. Because they border water bodies, floodplains have historically been popular sites to establish settlements. Human activities tend to concentrate on floodplains because water is readily available, the land is fertile and suitable for farming, transportation by water is easily accessible, and the land is flatter and easier to develop.
But human activity in floodplains frequently interferes with the natural function of floodplains. It can affect the distribution and timing of drainage, thereby increasing flood problems. Human development can create local flooding problems by altering or confining drainage channels. This increases flood potential in two ways: it reduces the stream’s capacity to contain flows, and it increases flow rates or velocities downstream during all stages of a flood event. Human activities can interface effectively with a floodplain as long as steps are taken to mitigate the activities’ adverse impacts on floodplain functions.
4.5.6.1 Plans, Policies, and Regulatory Environment
National Flood Insurance Program (NFIP)
The NFIP makes federally-backed flood insurance available to homeowners, renters, and business owners in participating communities. The City of Napa participates in NFIP.
For most participating communities, FEMA has prepared a detailed Flood Insurance Study (FIS). The study presents water surface elevations for floods of various magnitudes, including the 1-percent annual chance flood (the 100-year flood) and the 0.2-percent annual chance flood (the 500-year flood).
Base-flood elevations and the boundaries of the 100- and 500-year floodplains are shown on Flood Insurance Rate Maps (FIRMs), which are the principal tool for identifying the extent and location of the flood hazard. FIRMs also designate and display the floodway, which is the channel of the river or stream and adjacent land that must remain free from obstruction so that the 100-year flood can be conveyed downstream. FIRMs are the most detailed and consistent data source available, and for many communities, they represent the minimum area of oversight under their floodplain management program.
The most recent countywide FIRM was completed on November 12, 2014.
Participants in the NFIP must, at a minimum, regulate development in floodplain areas in accordance with NFIP criteria. Before issuing a permit to build in a floodplain, planning committee must ensure that three criteria are met:
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▪ New buildings and those undergoing substantial improvements must, at a minimum, be elevated to protect against damage by the 100-YR flood;
▪ New floodplain development must not aggravate existing flood problems or increase damage to other properties; and
▪ New floodplain development must exercise a reasonable and prudent effort to reduce its adverse impacts on threatened salmonid species.
Structures permitted or built in the city before December 31, 1974, are called “pre-FIRM” structures, and structures built afterward are called “post-FIRM.” Post-FIRM properties are eligible for reduced flood insurance rates. Such structures are less vulnerable to flooding since they were constructed after regulations and codes were adopted to decrease vulnerability. Pre-FIRM properties are more vulnerable to flooding because they do not meet code or are located in hazardous areas. The insurance rate is different for the two types of structures.
Compliance is monitored by FEMA regional staff and by the California Department of Water Resources under a contract with FEMA. Maintaining compliance under the NFIP is an important component of flood risk reduction. This HMP identifies initiatives to maintain compliance and good standing under the NFIP.
Community Rating System (CRS)
The CRS is a voluntary program within the NFIP that encourages floodplain management activities that exceed the minimum NFIP requirements. CRS activities can help to save lives and reduce property damage. Communities participating in the CRS represent a significant portion of the nation’s flood risk; over 66 percent of the NFIP’s policy base are communities in the CRS. Flood insurance premiums are discounted to reflect the reduced flood risk resulting from community actions that meet the three goals of the CRS: 1) reduce flood losses, 2) facilitate accurate insurance rating, and 3) promote awareness of flood insurance.
For participating communities, flood insurance premium rates are discounted in increments of five percent according to the community’s classification. For example, a Class 1 community would receive a 45 percent premium discount, and a Class 9 community would receive a five percent discount. Class 10 communities are those that do not participate in the CRS; they receive no discount. The CRS classes for local communities are based on 18 creditable activities related to public information, mapping and regulations, flood damage reduction, and flood preparedness. Table 4-50 lists NFIP and CRS statistics for the city.
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Table 4-50: Flood Insurance Statistics for the City of Napa NFIP and CRS Status & Information
City of Napa
NFIP Status Participating since 09/05/79
CRS Class 7
Policies in Force 977
Policies in SFHA 692
Policies in non-SFHA 285
Total Claims Paid 870
Paid Losses $20,489,632
Repetitive Loss Properties 55
Severe Repetitive Loss Properties 10
Repetitive Loss Payment by NFIP on Building $4,822,687
Repetitive Loss Payment by NFIP on Contents $1,699,117
Note: The Privacy Act of 1974 (5 U.S.C. 522a) restricts the release of certain types of data to the public. Flood insurance policy and claims data are included in the list of restricted information. FEMA can only release such data to state and local governments, and only if the data are used for floodplain management, mitigation, or research purposes. Therefore, this plan does not identify the repetitive loss properties or include claims data for any individual property.
Cobey-Alquist Floodplain Management Act
The Cobey-Alquist Floodplain Management Act of 1965 provided state-level guidance and review of floodplain management, including the review of floodplain management plans, establishment of floodplain management regulations, and the use of designated floodways. The California Department of Water Resources (DWR) adopts regulations, maintains a statewide flood management data collection and planning program, manages a statewide grant program, and helps coordinate emergency flood response operations.
Urban Water Management Plans (UWMP)
Jurisdictions either supplying over 3,000 acre-feet of water annually or serving more than 3,000 urban connections are required to submit an UWMP and update these plans every five years. Most jurisdictions participating in this HMP have urban water management plans, explored in more detail in jurisdictional annex capabilities assessments.
Most relevant to flood mitigation, UWMPs explore stormwater capacity and assist in planning and funding future stormwater needs. UWMPs contain important information on long-term water supply planning and managing demands in times of drought, so UWMPs are important for drought hazard planning and discussed in Section 4.5.2.1. (CDWR, 2021)
2006 Final Storm Drainage Master Plan
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City. It focuses on the stormwater collection system and the storm drains that convey runoff to the Napa River and creeks.
City of Napa General Plan
The City of Napa 2015 General Plan includes a number of goals, policies, and implementation programs in its Health and Safety Element. These provisions are designed to anticipate flooding and ensure the reduced risk to life and property from flooding. The City is currently updating its General Plan and will include flood safety and mitigation policies and programs as part of the update.
Floodplain Management Regulationsin City of Napa Municipal Code, § 17.38.060 The City of Napa Municipal Code contains methods and provisions designed to reduce flood loss for the City. It includes specific development standards for all new construction in floodplains such as the requirement that all new structures be secured to a permanent foundation system, and the elevation of a structure’s lowest floor to be located above base flood levels.
4.5.6.2 Past Events
The City of Napa has a long history of destructive flood events. In a 36 year time span (1961-1997), 19 floods caused more than $542 million in residential property damage. During a 1986 flood, 20 inches of rain fell in a 48-hour period, resulting in 3 deaths, the destruction of 250 homes, damage to 2,500 homes, and the evacuation of 5,000 residents. Flooding in 1995 and 1997 created similar destruction, which led to a longterm project to address these flooding issues, described in more detail in Section 4.5.6.3.2. (FEMA, 2021) Table 4-51 shows the flood events that took place in the City of Napa since the year 2000, some of which caused either property or crop damage. (NOAA, 2021)
Table 4-51: City of Napa Flood Events Since 2000
Date
Property Damage
Value ($)
Crop Damage
Value ($)
12/31/2005 0 0
1/1/2006 115,000,000 32,500,000
10/13/2009 10,000 0
11/30/2012 500 0
12/23/2012 2,000 0
12/11/2014 0 0
2/6/2015 0 0
12/15/2016 0 0
1/3-10/2017 0 0
1/8/2017 0 0
1/10/2017 0 0
2/20/2017 0 0
11/29/2018 0 0
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Date
Property Damage
Value ($)
Crop Damage
Value ($)
1/6/2019 0 0
1/16/2019 0 0
2/4/2019 0 0
2/13-14/2019 0 0
2/26-27/2019 0 0
Source: NOAA Storm Events Database
4.5.6.3 Location
The City of Napa, due to its varied geography and climate, has a significant number of potential flood sources along the Napa River and its tributaries. Figure 4-34 displays FEMA flood zones within the City of Napa. More detailed views of FEMA flood zones are available for planning committee through the Risk Assessment Mapping Platform (RAMP) on http://mitigatehazards.com/napahmp/ramp/. The Repetitive Loss Areas Analysis (RLAA) in Section 4.5.6.3.1 describes many of the most problematic areas.
Flood hazard conditions can exist along the entire length of the Napa River as it flows through the City as well as along the course of several tributary creeks. Flooding in the City has occurred when the Napa River’s flow at Oak Knoll Avenue, which is just north of the City limits, has exceeded about 15,000 cubic feet per second. Some areas (typically agricultural land) will remain flooded for several weeks due to inadequate drainage, however, it is more typically true that such areas are only inundated for between one and three days. (City of Napa Hazard Mitigation Plan, 2015) Napa Creek floodwaters have had a particularly significant impact on the center of the City. For instance, during the 1986 flood, Napa Creek overflowed on the south side of its banks. It flooded areas along Coombs Street and the parkway Plaza Mall as well as the downtown area. This was similar to a flood event which occurred in 1942. The completion of the Napa Creek Flood Protection Project is a significant mitigation to the threat of flooding and has been predicted to significantly reduce or eliminate property damage from 100-year storm events, especially in the downtown Napa River Oxbow area. (Id.) Localized flooding may sometimes occur outside of recognized drainage channels or delineated floodplains due to a combination of locally heavy precipitation, increased surface runoff, and inadequate facilities for drainage and stormwater conveyance. Such events most typically occur in flat areas and in urbanized areas with extensive impermeable surfaces. Local drainage may result in “nuisance flooding,” in which streets or parking lots are temporarily closed and minor property damage occurs.
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Figure 4-34: FEMA Flood Risk Exposure
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DWR Flood Awareness Zones and 200-year Floodplain in Sacramento Watershed DWR designates Flood Awareness Zones to highlight areas of additional flood, extending beyond FEMAdesignated floodplains, that pose a threat throughout the state. The designation provides communities and residents an additional tool in understanding potential flood hazards. These floodplains are shown simply as flood-prone areas without specific depths and other flood hazard data. Flood awareness zones for Napa City are shown in Figure 4-35.
DWR’s best available mapping (BAM) also includes the 200-year floodplain as identified by the Army Corps of Engineers from the 2002 Sacramento and San Joaquin River Basins Comprehensive Study. The City of Napa does not have mapped 200-year floodplains.
Napa River- Napa Creek Flood Protection Project
After a long history of destructive flooding in Napa, the City undertook a comprehensive project to reduce flooding, known as the Napa River-Napa Creek Flood Protection Project. Parts of the project have been completed while other parts are ongoing. The location of flooding in the city has already been significantly reduced thanks to completed phases of the Project.
The first major hurdle the City faced was funding such a large-scale effort. Two-thirds of voters in Napa County passed Measure A in March of 1998. This half-cent local sales tax levy provides a funding mechanism for the local share of the project cost and helped solidify the partnership between the Napa County Flood Control and Water Conservation District (NCFCWCD) and the U.S. Army Corps of Engineers.
Measure A funds flood protection, drainage improvements, dam safety, and watershed management projects for each community in Napa County and in the unincorporated area of the county. (FEMA, 2021) The project is still ongoing and includes: the acquisition and removal of more than 50 mobile homes, 16 residences, and 28 commercial buildings from flood-prone areas; the creation of over 400 acres of emergent marsh and 150 acres of seasonal wetlands; the removal, reconstruction, and elevation of several bridges; the elevation of railroad tracks; home and utilities elevations; the creation of structural flood control elements such as widened stream beds, flood walls, levees, and culverts; and the construction of three detention basins with accompanying pump stations. (Id.) The Oxbow Bypass is a key part of the project. The bypass is a wet/dry channel that allows for the inundation of high flows from the Napa River during winter months to reduce high flows that would often back up and flood downtown Napa. The bypass includes flood gates to further protect downtown Napa from flooding. The bypass also serves as a community park, Oxbow Commons, which opened in 2015. The bypass is just one of many successes of the Project throughout the city that have reduced flood impacts. 1-26-2022 Submittal EXHIBIT A Page 191 of 416
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Figure 4-35: City of Napa Best Available Mapping (DWR) Flooding 1-26-2022 Submittal EXHIBIT A Page 192 of 416
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4.5.6.4 Repetitive Loss Area Analysis
A repetitive loss (RL) property is a FEMA designation, defined as an insured property (or formerly insured) that has made two or more claims of more than $1,000 in any rolling 10-year period since 1978. Claims must be at least 10 days apart but within 10 years of each other. The term “rolling 10-year period” means that a claim of $1,000 can be made in 1991 and another claim for $2,500 in 2000, or one claim in 2001 and another in 2007, as long as both qualifying claims happen within 10 years of each other. A RL property may be classified as a Severe Repetitive Loss (SRL) property under certain conditions: the property has had four or more claims of at least $5,000, or at least two claims that cumulatively exceed the buildings reported value.
Extensive FEMA NFIP databases are used to track claims for every participating community, including the City of Napa. Currently, the city contains 55 unmitigated RL properties city-wide. The total dollar amount of claims paid to date by the NFIP for these RL properties are made available in Table 4-50, previously presented, and in Figure 4-36.
A property does not have to be currently carrying a flood insurance policy to be considered a RL or SRL property. Often homes in communities do not carry flood insurance but are still on the community’s repetitive loss list. The “repetitive loss” designation follows a property from owner to owner, from insurance policy to no insurance policy, and even after the property has been mitigated. Having an insurance policy and making claims that fall into the repetitive loss criteria will put a property on the RL list. Even after the policy on a property has lapsed or been terminated, the property will remain on the City’s RL list.
This Repetitive Loss Areas Analysis (RLAA) examines areas where multiple RL properties exist in close proximity to each other and share similar flooding source conditions. Six RL areas have been identified as part of the city’s RLAA. Most RLAA areas are a result of flood damage caused by the Napa River. Local tributaries such as Napa Creek and Kreuse Creek also contribute to flood losses during high water events in RLAA areas. Figure 4-36 shows the repetitive loss areas in the City of Napa along with the information on claim data, historic loss information and current property value information in total. Figure 4-37 through Figure 4-42 show individualized claim and property data for each repetitive loss area.
The Privacy Act of 1974 (5 U.S.C. 522a) restricts the release of certain types of data to the public, including Flood insurance policy and claims data. FEMA can only release such data to state and local governments, and only if the data is used for floodplain management, mitigation, or research purposes. Therefore, this plan does not identify the repetitive loss properties or include claims data for any individual property. 1-26-2022 Submittal EXHIBIT A Page 193 of 416
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Figure 4-36: City of Napa Repetitive Loss Areas
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Stonecrest RL Area
The Stonecrest RL Area is located near Stonecrest Avenue and Highway 121. This repetitive loss area consists of two properties on along the banks of the Napa River. Figure 4-37 indicates the area of generalized repetitive loss claims, payout information, and the FEMA identified flood hazard at Stonecrest.
Most properties on the Napa River have significant risk to flooding, as indicated by past flood occurrences and past claims. One property is a SLR property with more than seven different claims dating back to 1985.
Most properties or homes are not within the FEMA 100-YR Floodplain; however,there is a low-lying section of land along the banks of the Napa River that may contribute to flood damage in this area. The SFHA “Effective” FIRM indicates Base Flood Elevations (BFEs) of approximately 27.2 to 26.6 feet for the Napa River Floodway and the low-lying area is approximately 22 to 25 feet.
RiverPointe RL Area
RiverPointe RL Area is located along the west bank of the Napa River at Lincoln Avenue. This area is named after the RiverPointe Napa Valley Resort. It’s known by local flood control and emergency management personnel that the Napa River jumps the west bank at this location due to the capacity of the Lincoln Avenue Bridge. Flood waters travel from the Napa River west down Lincoln Avenue and inundate areas north of Lincoln Avenue first; waters then flow across Lincoln Avenue at low-lying areas to the south. This repetitive loss area consists of 28 properties, located both north and south of Lincoln Avenue. Figure 4-38 indicates the area of generalized repetitive loss claims and payout information for RiverPointe. Most properties within this area have significant risk to flooding, as indicated by past flood occurrences and past claims, especially at the intersection of Lincoln Avenue and Soscol Avenue. Six properties in the RiverPointe Area are SLR properties. All RL properties within the RiverPointe Area are within the FEMA 100-YR Floodplain, and almost half are within the floodway of the Napa River. It is important to note that over four million dollars of claims have been paid by the NFIP in this area. Average payouts are more than $50,000 for each occurrence due to the commercial nature of many properties.
Soscol North RL Area
Soscol North RL Area is just south of the RiverPointe RL Area on Soscol Avenue. This RL area consists of five properties between Yount Street and Caymus Street along Yajome Street. Most properties within this area have significant risk of flooding, as indicated by past flood occurrences, past claims, and the proximity to the floodway. Figure 4-39 indicates the area of generalized repetitive loss claims, payout information, and the FEMA-identified flood hazard. All properties within this RL Area are within the FEMA 100-YR Floodplain. The SFHA “Effective” FIRM indicates BFEs of approximately 21 feet within this area, with most of the damage caused by the split flow of the Napa River during high water events and the lowlying nature of this area in the floodway.
Oxbow West RL Area
The Oxbow West RL Area is located on the west bank for the Napa River oxbow. This RL area consists of three RL properties within the oxbow, to the east of the “dry river bypass.” Most properties within the oxbow have significant risk to flooding, as indicated by past flood occurrences and past claims. Figure 4-40 indicates the area of generalized repetitive loss claims, payout information, and the FEMA-identified flood 1-26-2022 Submittal EXHIBIT A Page 195 of 416
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hazard for this area. Flood risk has been reduced in recent years with the construction of the Napa River dry bypass and construction of flood gates to protect the oxbow from high water events; however, these RL properties are unmitigated according to FEMA. The SFHA “Effective” FIRM indicates BFEs of approximately 19.5 feet for the dry bypass floodway and approximately 19.7 feet for areas in the 100-YR floodplain near Vernon Street. Average payouts are more than $40,000 for each occurrence due to the commercial nature of the properties.
Oxbox East RL Area
The Oxbow East RL Area is located on the east bank for the Napa River oxbow. This RL area consists of 13 RL properties on the east bank of the Napa River. Most properties on within the oxbow have significant risk to flooding, as indicated by past flood occurrences and past claims. Figure 4-41 indicates the area of generalized repetitive loss claims, payout information and the FEMA-identified flood hazard for this area.
Flood risk has been reduced in recent years with the construction of the Napa River dry bypass to alleviate this neighborhood from high water events; however, these RL properties are unmitigated according to FEMA. All properties in this RL Area are within the FEMA 100-YR Floodplain and the Napa River oxbow overflow area. The SFHA “Effective” FIRM indicates BFEs of 19.7 feet for areas near 2nd and Post Streets down to 18.3 feet for areas near 3rd Street. It is important to note that over one million dollars of claims have been paid by the NFIP in this area.
Soscol South RL Area
The Soscol RL Area is located on Soscol Ave between 8th Street and Sousa Lane. This RL area consists of 3 RL properties within the southern area of the Napa River oxbow overflow. Most properties in this overflow area have significant risk of flooding, as indicated by past flood occurrences and past claims. Figure 4-38 indicates the area of generalized repetitive loss claims, payout information, and the FEMA-identified flood hazard for this area. Flood risk has been reduced in recent years with the construction of the Napa River dry bypass to alleviate this neighborhood from high water events; however, these RL properties are unmitigated according to FEMA. All properties in this RL Area are within the FEMA 100-YR Floodplain. The SFHA “Effective” FIRM indicates BFEs of 16.2 feet for areas near 8th Street and dropping to approximately
15.7 feet for areas near Sousa Lane. It is important to note that Kreuse Creek may contribute to flood risk in this area. It’s been reported that Kreuse Creek backs up at Soscol Avenue and runs north down Soscol Avenue which may contribute to losses within this area. Average payouts are more than $45,000 for each occurrence due to the commercial nature of the properties. 1-26-2022 Submittal EXHIBIT A Page 196 of 416
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Figure 4-37: Stonecrest RL Area
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Figure 4-38: RiverPointe RL Area
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Figure 4-39: Soscol North RL Area
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Figure 4-40: Oxbow West RL Area
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Figure 4-41: Oxbow East RL Area
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Figure 4-42: Soscol South RL Area
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4.5.6.5 Measuring Frequency and Severity
The frequency and severity of flooding are measured using a discharge probability, a statistical tool that defines the probability that a certain river discharge or flow level will be equaled or exceeded within a given year. Flood studies use historical records to determine the probability of occurrence for the different discharge levels. The flood frequency equals 100 divided by the discharge probability. For example, the 100- YR discharge has a one percent chance of being equaled or exceeded in any given year. The “annual flood” is the greatest flood event expected to occur in a typical year. These measurements reflect statistical averages only; it is possible for two or more floods with a 100-YR or higher recurrence interval to occur in a short time period. The same flood can have different recurrence intervals at different points on a river.
The extent of flooding associated with a 1 percent annual probability of occurrence (the base flood or 100- YR flood) is used as the regulatory boundary by many agencies. This boundary is a convenient tool for assessing vulnerability and risk in flood-prone communities. Many communities have maps that show the extent and likely depth of flooding for the base flood. Corresponding water-surface elevations describe the elevation of water that will result from a given discharge level, which is one of the most important factors used in estimating flood damage.
4.5.6.6 Frequency and Probability of Future Occurrences The City of Napa will experience flooding in the future, with the probability of flooding in the City of Napa between 10 and 100% annually. Winter storms saturate soils in Napa County during the months of November through April. Napa County experiences “atmospheric river storms” that can deliver over an inch of rain per hour for extended time frames, producing flooding in local tributary streams and the Napa River. The 100-year flood is calculated to be the level of flood water expected to be equaled or exceeded every 100 years on. The term is used to describe an event that has a 1-in-100 chance of happening in any given year. In reality, there is a 65% chance that there will be a 100-year flood in 100 years. Likewise, a 50- year flood has a 2% chance of happening in any given year, and there’s a 4% chance of a 25-year flood every year. Calculations are based on less than a hundred years of flood records. The Napa River Flood Project is being constructed to protect the community from this 100-year event, which would be a larger flood than the 1986, 1995, or 2005 flood events.
Flooding in California is often associated with the El Nino weather phenomenon. El Nino is a term originally used to describe the appearance of warm (surface) water from time to time in the eastern equatorial Pacific region along the coasts of Peru and Ecuador. This ocean warming can strongly affect weather patterns all over the world. El Nino events are often associated with above-normal precipitation in the southwestern United States. El Niños often occur during the Christmas season. La Niña is the opposite or “cold phase” of the El Niño cycle. Current understanding suggests that El Niño has a return period of four to five years. When an El Niño event occurs, it often lasts from 12 to 18 months. (National Oceanic and Atmospheric Administration , 2020)
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4.5.6.7 Severity and Extent
The main factors affecting flood damage are water depth and velocity. Deeper and faster flood flows can cause more damage. Shallow flooding with high velocities can cause as much damage as deep flooding with slow velocity. This is especially true when a channel migrates over a broad floodplain, redirecting high velocity flows and transporting debris and sediment. Flood severity is often evaluated by examining peak discharges; Table 4-52 lists peak flows used by FEMA to map City of Napa floodplains.
Table 4-52: Summary of Relevant Discharges in Napa County Drainage
sq. Miles
Peak Discharge (cubic feet/second)
Flooding Source/Location 10-
percent
2-
percent
1-percent 0.2-
percent
Blossom Creek
At confluence with Napa River 3.4 1,000 N/A 1,700 2,000 Cyrus Creek
At confluence with Napa River 2.9 900 N/A 1,500 1,900
Garnett Creek
At confluence with Napa River 6.9 1,900 N/A 3,200 3,900 Napa Creek
At mouth 14.9 * * 4,300 *
At the City of Napa corporate limits 14.9 2,200 * 3,500 4,500 Napa River
Upstream of Bull Island 324 25,500 38,900 45,200 69,000 Upstream of Imola Avenue 300 26,770 39,200 44,390 53,450 Upstream of confluence of Tulucay Creek * 25,810 38,010 42,720 51,260 Upstream of confluence of Napa Creek * 20,040 35,600 40,100 48,300 Upstream of Trancas Street * 22,750 33,430 39,000 44,540 Near the City of Napa (Oak Knoll Avenue) 281 18,500 * 33,000 46,000 Upstream of Oak Knoll Avenue 218 18,400 28,100 32,700 50,300 Near the City of St. Helena (Zinfandel Lane) 81.4 13,000 * 21,000 25,000 At Dunweal lane 23 7,800 N/A 12,500 15,000
At State Highway 29 21.6 7,400 N/A 12,000 14,500
At upstream corporate limits 5.4 3,300 N/A 5,100 6,400
Salvador Creek
At confluence with Napa River * * * 3,910 *
At Big Branch Road 1.8 * * 3,213 *
Sulphur Creek
At confluence with Napa River to Sulphur Creek
Tributary
9.2 * * 3,3306 *
Upstream of Sulphur Creek Tributary 7.6 * * 3,110 *
6 Flow rate reduction due to capacity restriction
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Drainage
sq. Miles
Peak Discharge (cubic feet/second)
Flooding Source/Location 10-
percent
2-
percent
1-percent 0.2-
percent
Sulphur Creek Tributary
At confluence with Sulphur Creek 1.1 * * 500 *
Tulucay Creek
At Soscol Avenue * 2,880 * 4,530 5,500
Upstream of Camille Creek * 2,050 * 3,250 4,050
* Data not available
Source: Table 5 Summary of Discharges from FEMA FIS Text, 2011
4.5.6.8 Warning Time
The type and rate of flooding experienced in the City of Napa varies. In general, warning times for floods can be between 24 and 48 hours. Seasonal notification for flooding can enhance awareness for citizens at risk, and, when communicated effectively, advance notification can reach target audiences on a large scale.
DWR Awareness Zones Notification
The Flood Risk Notification Program (FRN Program) is part of DWR’s FloodSAFE California Initiative. The program’s key goal is to increase flood risk awareness by effectively communicating that risk to individual property owners, the public, and local, state, and federal agencies. To achieve this goal, the FRN Program sends out annual notices to property owners whose property is at risk of flooding, provides people with useful ways to assess risk and reduce flood loss, and expanded its interactive Flood Risk Notification website, among many other initiatives. The notice to landowners informs recipients of their property’s potential flood risks and potential sources of flooding and offers flood emergency planning and preparedness tips. It encourages recipients to take preventative actions such as purchasing flood insurance, elevating or “floodproofing” their buildings, and preventing blockage of channels, drains, and ditches.
4.5.6.9 Secondary Hazards
The most problematic secondary hazard for flooding is bank erosion, which in some cases can be more harmful than actual flooding. Flooding is also responsible for landslides when high flows over-saturate soils on steep slopes and cause them to fail. Hazardous materials spills are a secondary hazard of flooding if storage tanks rupture and spill into streams or storm sewers. (Department of Environmental Conservation, 2020)
Wildland fires within a watershed can exacerbate flood hazards by virtue of increased rate and volume of runoff and attendant erosion and sediment discharge. (USGS, 2020) 1-26-2022 Submittal EXHIBIT A Page 205 of 416
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4.5.6.10 Climate Change Impacts
The effects of climate change are varied and include warmer and more varied weather patterns, melting ice caps, and poor air quality, for example. As a result, climate change will likely worsen a number of natural hazards, including flooding. Climate change will shift rainfall patterns, making heavy rains more frequent in many areas. An increase in heavy rain events will lead to more flooding, including flash floods that happen suddenly as a result of heavy rain and localized flooding, which involves the pooling of water in low-lying areas. Heavy rain events can inundate and overwhelm stormwater drainage systems resulting in localized flooding where pooling of water can cause significant damage to buildings.
Overwhelmed stormwater drainage facilities also create hazardous conditions on roadways where water pools in low lying areas creating dangerous driving conditions. (US EPA, 2020)
4.5.6.11 Flood Vulnerability Analysis
Both an exposure analysis and Hazus loss estimation analysis were conducted to develop the flood vulnerability analysis for the City of Napa. Flood exposure numbers were generated using the inventories outlined in 4.5.6.11.1 County inventories were overlaid with FEMA delineated flood plains to determine exposure. These risk assessment exposure analysis values do not include Hazus -generated results.
Hazus flood vulnerability data was generated using a Level 2 Hazus 4.2 analysis. Hazus is a FEMA software product that uses a GIS to analyze 100-year depth grids derived from FEMA 100-year “A” zones with Base Flood Elevations (BFE) to estimate loss. Parcel data defined in 4.5.6.11.1 was imported into Hazus as User Defined Facilities (UDF) and serves as the basis for replacement and content cost estimations as well as associated loss. Where flood vulnerability is mentioned absent of Hazus, exposure analysis figures are used. Figure 4-43 displays a snapshot of flood exposure and damage estimation in the City of Napa.
Flood Exposure
The tables and graphs in this section detail the populations, properties, and infrastructure exposed to flooding in the City of Napa. Flood exposure is categorized by exposure to different flood hazard zones, including the floodway, flood fringe, 100-year floodplain, and 500-year floodplain. The tables and graphs also include a category of the 100-year total, which is a combined total of floodway, flood fringe, and 100- year floodplain categories. The 500-year sans 100-year category includes only the 500-year floodplain, and the 500-year total includes all of the categories combined. Refer to section 4.5.6 for floodplain definitions to better understand these flood hazard areas.
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Figure 4-43: FEMA Flood Risk Exposure and Snapshot Map
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Population
Population counts of those living in the floodplain were generated by analyzing County assessor and parcel data that intersect with the 100-YR and 500-year floodplains identified on FIRMs. Using GIS, U.S.
Census Bureau information was used to intersect the floodplain, and an estimate of population was calculated by weighting the population within each census block and track with the percentage of the flood risk area. Using this approach, Table 4-53 and Figure 4-44 display the results of this analysis showing how much of the population of the City of Napa is exposed to flood hazard zones.
Table 4-53: Summary Population Exposure to Flood in the City of Napa Total Population
City of Napa 79,722
Flood Hazard Zone Population Count % of Total
Flood Fringe 6,282 7.88%
Floodway 2,003 2.51%
100-YR Total 8,285 10.39%
500-YR sans 100-YR 3,738 4.69%
500-YR Total 12,023 15.08%
Figure 4-44: Flood Population Exposure Summary
Economy
Flooding can significantly impact the agricultural industry, including wine producers. The City of Napa has strong ties to Napa County's agricultural economy because of its location to the Napa Valley wine grape growing region. Protecting the wine industry, and the tourism it generates, is vital to the city's economy. Flooding interferes with crop production and impacts the growth of wine grapes and other 6,282
2,003
8,285
3,738
12,023
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
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produces by preventing oxygen absorption, leading to plant death and affecting yields. Oxygen deprivation is the primary source of damage to plants from flooding, other than from lodging. Surface floodwaters and water-logged soils significantly reduce the amount of oxygen available to plants, which require oxygen to produce high-energy compounds used in nearly all life reactions, and also cause build-up of harmful chemicals. The effect is drastically reduced metabolism and, eventually, death if oxygen levels are reduced for more than 36 to 48 hours; the effects are often reversible if the duration of low oxygen conditions are limited within this tolerance. (Wiebold, 2007)
Public Health
Following any natural disaster that leaves excess moisture or standing water in its wake, such as a flood, the risk of mold growth in homes or other buildings greatly increases. Controlling moisture within a structure is the most critical factor for preventing mold growth. Any exposed buildings should be cleaned up and dried out quickly, within about 24 to 48 hours if possible, and any remaining wet porous items should be removed. People with asthma, allergies, respiratory conditions, or immune suppression are at the greatest risk for health effects from contact with mold. (CDC, 2020) Structures and Parcel Value
Table 4-54 summarizes parcels in the City of Napa that are exposed to flood hazard areas. The beginning of Section 4.5.6 includes definitions of the various flood hazard areas.
Table 4-54: Parcels Exposed to NFIP Flood Zones in the City of Napa Total Parcels Total Market
Value ($)
Total Content
Value ($) Total Value ($)
City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Flood Hazard Zone Parcel Count % of Total Market Value
Exposure ($)
Content Value
Exposure ($) Total Exposure ($) % of Total
Flood Fringe 2,016 5.6% $576,206,795 $454,169,818 $1,030,376,613 4.3% Floodway 369 1.0% $67,265,095 $62,916,322 $130,181,417 0.5% 100-YR Total 2,385 6.6% $643,471,890 $517,086,140 $1,160,558,030 4.8% 500-YR sans 100-YR 2,155 6.0% $818,349,225 $600,579,238 $1,418,928,463 5.9% 500-YR Total 4,540 12.6% $1,461,821,116 $1,117,665,378 $2,579,486,493 10.7% Note: The table above does not display loss estimation results; the table exhibits total value at risk based upon the hazard overlay and Napa County Assessor data.
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Critical Facilities and Infrastructure
Table 4-55 summarizes the critical facilities and infrastructure located in the flood fringe, floodway, and 100-year and 500-year floodplains of the City of Napa.
Table 4-55: Critical Facility Points in the Floodplain
Infrastructure Type Flood Fringe Floodway 100-YR Total 500-YR sans 100-YR 500-YR Total
Essential Facility**- - - 2 2
Fire Station - - - 2 2
Hospital - - - - -
Police Station - - - - -
High Potential Loss 30 4 34 24 58
Adult Residential Facility - 1 1 - 1
Child Care Center 2 - 2 1 3
Church 1 - 1 3 4
Communication Tower 4 - 4 - 4
Dam - - - - -
Farm Worker Housing - - - - -
Foster Family Agency - - - 1 1
Historic Building 3 - 3 12 15
Home Care Organization - 1 1 - 1
Library - - - 1 1
*Real Property Asset 15 1 16 2 18
Residential Child Care - - - - -
Residential Elder Care Facility 2 - 2 1 3
School 1 - 1 2 3
Stream Rain Gauges 2 1 3 1 4
Water Treatment Plant - - - - -
Transportation and Lifeline 25 10 35 11 46
Bridge 13 10 23 1 24
Power Plant 1 - 1 - 1
Pressure Regulator Station 2 - 2 3 5
Pump Station - - - - -
Sample Station 8 - 8 7 15
Substation 1 - 1 - 1
Water Tank - - - - -
Grand Total 55 14 69 37 106
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Linear Utilities
It is important to determine who may be at risk if infrastructure is damaged by flooding. Roads or railroads that are blocked or damaged can isolate residents and can prevent access throughout the county, including for emergency service providers needing to get to vulnerable populations or to make repairs.
Bridges washed out or blocked by floods or debris also can cause isolation. Water and sewer systems can be flooded or backed up, causing health problems. Underground utilities can be damaged. Levees can fail or be overtopped, inundating the land that they protect. Table 4-56 shows critical facilities (linear) in the floodplain.
Table 4-56: Lifelines in the Floodplain in the City of Napa Lifelines (miles) - Flood Risk Exposure
Infrastructure Type (linear) Flood Fringe Floodway 100-YR Total 500-YR sans 100-YR 500-YR Total
Levee 2.1 - 2.1 0.0 2.1
Levee Centerline 0.4 0.0 0.4 0.8 1.2
Levee Flood Wall 0.1 0.3 0.4 0.5 0.9
NG Pipeline 3.9 0.1 3.9 1.0 4.9
Railroad 3.9 1.0 4.9 0.7 5.7
Street 24.1 4.7 28.8 18.2 47.0
Alley - - - - -
Cul-de-sac 0.0 0.0 0.1 0.0 0.1
Driveway 0.3 0.0 0.3 0.0 0.4
Interstate 0.2 0.0 0.3 0.2 0.5
Local road 0.9 0.1 1.0 1.6 2.6
Local road, major 14.7 2.3 17.0 12.1 29.1
Primary highway 1.6 0.1 1.8 0.5 2.3
Ramp 0.2 0.0 0.3 0.1 0.3
Road, parking area 0.9 0.0 0.9 0.1 1.1
State/county highway 5.2 2.0 7.2 3.6 10.7
Thoroughfare, major 0.0 - 0.0 0.0 0.0
Traffic circle - - - - -
Electric Transmission Line 2.7 0.5 3.2 0.6 3.8
Water Transmission Line 3.5 0.8 4.3 1.9 6.2
Grand Total 40.8 7.3 48.1 23.7 71.8
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Roads
The City of Napa maintains a list of flood inundation areas throughout the city, which includes a list of street closures during floods, as well as an interactive map of flood areas in the City of Napa. This information can be viewed at the following link: cityofnapa.org/313/Map-of-Flood-Inundation-Areas.
Water and Sewer Infrastructure
Water and sewer systems can be affected by flooding. Floodwaters can back up drainage systems, causing localized flooding. Culverts can be blocked by debris from flood events, also causing localized urban flooding. Floodwaters can get into drinking water supplies, causing contamination. Sewer systems can be backed up, causing wastewater to spill into homes, neighborhoods, rivers, and streams.
Flood Damage Estimation
Hazus calculates losses to structures from flooding by analyzing the depth of flooding and type of structure. Using historical flood insurance claim data, Hazus estimates the percentage of damage to structures and their contents by applying established damage functions to an inventory. For this analysis, all non-vacant parcels with current market values were used instead of the default inventory data provided with Hazus. Table 4-57 and Figure 4-45 shows the 100-year flood loss estimation (based on depth) in NFIP flood zones by occupancy type. Figure 4-46 and Table 4-59 shows the 500-year flood loss estimation (based on depth) in NFIP flood zones by occupancy type.
The city’s insurance data was obtained and formatted for use in Hazus for a detailed damage estimation of City-owned facilities. This combined government dataset has additional information, including the number of floors, building value, content value, and construction type that greatly enhances Hazus results.
Table 4-58 displays damage estimation for city facilities located in the 100-year flood zone.
Damage Estimation for 100-Year Floodplain
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Table 4-57: 100 YR Flood Damage Estimation by Occupancy Type Building Type Building Damage
($)
Building Damage
(% of total loss)
Content Damage
($)
Content
Damage
(% of
total
loss)
Total Damage ($) Proportion of
Loss (%)
Agriculture $384,741 0% $1,205,124 1% $1,589,864 2%
Commercial $8,853,498 10% $27,702,885 32% $36,556,384 42% Education $0 0% $0 0% $0 0%
Emergency $0 0% $0 0% $0 0%
Government $23,949 0% $5,250 0% $29,199 0%
Industrial $2,429,555 3% $5,810,221 7% $8,239,777 10%
Religion $0 0% $0 0% $0 0%
Residential $29,096,617 34% $10,898,545 13% $39,995,162 46% Total $40,788,360 47% $45,622,026 53% $86,410,386
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Figure 4-45: 100-YR Flood Damage Estimation by Occupancy Table 4-58 displays damage estimation for City facilities located in the 100-year flood zone.
Table 4-58: 100 YR Flood Damage Estimation of City Facilities Value Damage Pct. Estimated Losses (USD)
Building/Site
Name Count Structure Content Structure Content Structure Content Total Loss Pct. of Value Restroom 1 $127,547 $1 14% 79% $17,294 $1 $17,295 14%
Teen Center 1 $184,741 $28,169 2% 10% $2,937 $2,687 $5,623 3% Shop 2 $345,121 $63,628 1% 4% $3,718 $2,562 $6,280 2%
Equipment 2 $139,252 $5,787 0% 0% $0 $0 $0 0%
Corp Yard 1 $27,929 $1 0% 0% $0 $0 $0 0%
Office 1 $630,030 $57,841 0% 0% $0 $0 $0 0%
Misc 1 $1 $1 0% 0% $0 $0 $0 0%
Lot 1 $1 $1 3% 19% $0 $0 $0 11%
Grand Total 10 $1,454,622 $155,429 2% 12% $23,949 $5,250 $29,199 2% $0 $5,000,000 $10,000,000 $15,000,000 $20,000,000 $25,000,000 $30,000,000 $35,000,000 Agriculture
Commercial
Education
Emergency
Government
Industrial
Religion
Residential
Content Damage ($) Building Damage ($)
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Damage Estimation for 500-Year Floodplain
Table 4-59 and Figure 4-46 display the damage estimation summaries for the 500 yr. floodplain in the City of Napa by improved parcel type. There are no government property loss figures to report in the 500-year floodplain.
Table 4-59: Damage Estimation Summary for 500 yr. Floodplain Building Type Building Damage
($)
Building Damage
(% of total loss)
Content Damage
($)
Content
Damage
(% of
total
loss)
Total Damage ($) Proportion of
Loss (%)
Agriculture $0 0% $2,867 0% $2,867 0%
Commercial $224,120 1% $679,726 2% $903,847 3%
Education $0 0% $0 0% $0 0%
Emergency $0 0% $0 0% $0 0%
Government $0 0% $0 0% $0 0%
Industrial $14,642 0% $0 0% $14,642 0%
Religion $0 0% $0 0% $0 0%
Residential $21,073,609 72% $7,353,445 25% $28,427,054 97% Total $21,312,372 73% $8,036,038 27% $29,348,410
Note: Total Inventory Values
1 - Building Replacement Costs = $13,885,314,683
2 - Content Replacement Costs = $10,307,648,380
3 - Total Value = $24,192,963,063
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Figure 4-46: 500 YR Flood Damage Estimation by Occupancy Type
4.5.6.12 Future Trends in Development
Infrastructure has been developed to protect communities from flood damage-in particular the Napa River & Creek Flood Control Project. It serves to provide environmental restoration and economic development by incorporating a series of progressive engineering components in order to achieve 100-year flood protection while maintaining the living river principles. These engineering components include, but are not limited to, lowering of old dikes, marsh plain and floodplain terraces, and new dikes, levees, and floodwalls.
The city and its Planning Committee are equipped to handle future growth within flood hazard areas. The Planning Committee has a General Plan that address frequently flooded areas in its Safety Element. The planning committee has committed to linking its General Plans to this HMP. This will create an opportunity for wise land-use decisions as future growth impacts flood hazard areas.
4.5.6.13 Flood Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and flood hazard data. Flood problem statements for the City of Napa are listed in Table 4-60.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every $0 $5,000,000 $10,000,000 $15,000,000 $20,000,000 $25,000,000 Agriculture
Commercial
Education
Emergency
Government
Industrial
Religion
Residential
Content Damage ($) Building Damage ($)
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problem statement. See Table 5-6 for a full list of mitigation actions and the corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-60 and Table 5-6.
Table 4-60: Flood Problem Statements
Problem No.
Hazard
Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-FL-CN-20 Flood Impact PRV - Prevention ,
PPRO - Property
Protection , SP -
Structural Projects
The following critical facilities are located
in the 100-YR floodplain: City Corporation
Yard (770 Jackson Street), Elder Res Facility
(3158 Browns Valley Rd), Adult Res Facility
(622 Imperial Way), Communication Towers
(end of Streblow Dr)
ma-FL-CN-49,
ma-FL-CN-24,
ma-FL-CN-23,
ma-AH-CN-13
ps-FL-CN-21 Flood Impact PPRO - Property
Protection , SP -
Structural Projects
Two City Fire Stations are located in the
100-year floodplain: No. 3 (2000 Trower
Ave.) and 4 (251 Gasser Dr.)
ma-FL-CN-23,
ma-FL-CN-24,
ma-FL-CN-49,
ma-AH-CN-13
ps-FL-CN-22 Flood Impact PRV - Prevention ,
PPRO - Property
Protection , PE&A -
Public Education &
Awareness
There are approximately 2,385 parcels
located in the 100-YR floodplain, with a total
structure value of $2,254,352,423
ma-FL-CN-49,
ma-FL-CN-23
ps-FL-CN-23 Flood Impact SP - Structural Projects Existing Flood Plain zoning layer is out of date for numerous repetitive properties in
City limits
ma-FL-CN-30
ps-FL-CN-24 Flood Impact PRV - Prevention , SP -
Structural Projects
Overall flood control on the Napa River
remains a concern as the Flood Control
Project continues.
ma-FL-CN-49
ps-FL-CN-25 Flood Victim PPRO - Property
Protection , PE&A -
Public Education &
Awareness
There are approximately 4,463 people living
in the 100-YR flood plain in City limits; 3,739
live in the 500-yr flood plain.
ma-FL-CN-29,
ma-FL-CN-25
ps-FL-CN-26 Flood Victim PE&A - Public
Education & Awareness
Property owners are unaware of flood risks
and responsibility to maintain drainage
ways.
ma-AH-CN-3
ps-FL-CN-27 Flood Victim PRV - Prevention ,
PE&A - Public
Education & Awareness
Homeless residents of encampments along
the Napa River face obstacles to rapid
evacuation in advance of a flood
emergency.
ma-AH-CN-7,
ma-AH-CN-3
ps-FL-CN-28 Flood Threat PRV - Prevention , SP -
Structural Projects
Blocked storm drains and undersized
culverts create localized street flooding in
residential areas, especially in North Napa
off Valencia and the Silverado/ Trancas
area.
ma-FL-CN-49,
ma-FL-CN-26,
ma-FL-CN-49,
ma-FL-CN-23,
ma-FL-CN-24
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4.5.7 Extreme Weather Hazard Profile
Extreme weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life. Extreme weather events can be categorized into two groups. Those that form over wide geographic areas are classified as general extreme weather while those with a more limited geographic area are classified as localized extreme weather. The HMP Planning Committee identified three types of extreme weather events that typically impact the City of Napa:
▪ High Wind ▪ Heavy Rain ▪ High Heat
The following are characteristics of extreme weather events that can occur in the City of Napa.
High Wind
Damaging winds are classified as those exceeding 60 mph. Damage from such wind accounts for half of all extreme weather reports in the lower 48 states and is more common than damage from tornadoes.
Wind speeds can reach up to 100 mph and produce a damage path extending for hundreds of miles. There are several types of damaging winds:
▪ Straight-Line Wind: Any thunderstorm wind that is not associated with rotation. This term is used primarily to differentiate from tornado winds. Most thunderstorms produce some straight-line winds as a result of outflow generated by the thunderstorm downdraft. (The National Severe Storms Laboratory, n.d.)
▪ Downdraft: A small-scale column of air that sinks toward the ground. Downdraft is a general term for a common component of thunderstorms, both mild and severe, that forms as part of the convective cycle. (Id.)
▪ Microburst: A small, concentrated downdraft that produces an outward burst of damaging winds at the surface. Microbursts are generally less than 2.5 miles across and short-lived, lasting only five to 10 minutes, with maximum wind speeds up to 168 mph. Microbursts may or may not be accompanied by precipitation, referred to as being wet or dry. (Id.) ▪ Downburst: A strong downdraft larger than 2.5 miles horizontally, resulting damaging winds on or near the ground. Downburst winds may begin as a microburst and spread over a wider area.
Downbursts most often occur with thunderstorms, but can also occur with showers too weak to produce thunder. (Id.)
▪ Gust Front: A gust front is the leading edge of rain-cooled air that interacts with ambient air, often warmer thunderstorm inflow. (Id.)
▪ Bow Echo: A bow echo is the radar signature of a linear thunderstorm front bent outward in a bow shape. Damaging straight-line winds often occur near the center and tornadoes can occur along the leading edge of a bow echo. Bow echoes can be 200 miles long, last for several hours, and produce extensive wind damage at the ground. (Id.)
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Heavy Rain
Heavy rain can lead to flooding even on dry soil and especially on impervious surfaces. In urban areas, direct runoff is relatively extensive, not only because of the density of roofs and impermeable pavements which allow less rain to infiltrate the ground but also because storm-sewer systems carry more water directly to the streams and lakes. In a more natural or undeveloped area, direct runoff is considerably less. (United States Geological Survey, n.d.) The average annual rainfall in the City of Napa is 23.88 inches, with the majority occurring from November to March. (City of Napa Hazard Mitigation Plan, 2015) Most of the precipitation falls during the winter. Rainfall is often from storms that move in from the northwest.
Virtually no rainfall occurs during the summer months.
High Heat
Heat waves are periods of abnormally hot weather lasting days to weeks. The number of heat waves has been increasing in recent years across the United States and locally, and climate change will continue to cause extreme heat events more often. Studies show that by the end of this century, the number of days with temperatures reaching 100°F or more is projected to increase dramatically as a result of climate change. What the public now considers to be an exceptional event could become routine across much of the country. As temperatures rise and extreme heat events become longer, more severe, and more frequent, experts expect to see more health problems and deaths caused by heat. (CDC, 2013) Extreme heat events are defined by summertime weather that is substantially hotter and more humid than average for a given location at that time of year. (CDC, 2017) Heat kills by taxing the human body beyond its abilities. Among natural hazards, only the cold of winter, not lightning, hurricanes, tornados, floods, or earthquakes, takes a greater toll. (Ready, 2021) In a normal year, about 600 Americans succumb to the demands of extreme heat. (CDC, 2021) In California, a record number of heat related deaths occurred in 2006. At least 140 deaths occurred between July 15 and August 1 and about 16,000 more emergency room visits occurred in that year due to a record-breaking heat wave. (California Office of Environmental Health Hazard Assessment, 2019)
4.5.7.1 Plans, Policies, and Regulatory Environment
There are very few formal regulations that pertain directly to extreme weather events. The California Building Code, 7 adopted by the City of Napa, is generally adequate to properly address development impacts from extreme weather events. The City is currently updating its General Plan and will include extreme weather safety and mitigation policies and programs as part of the update.
4.5.7.2 Past Events
Extreme weather events for the City of Napa include heavy rain, high wind, and high heat. The following summarizes National Oceanic and Atmospheric Administration (NOAA) data on the number of extreme 7 Available at https://www.dgs.ca.gov/BSC/Codes.
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weather events, including noteworthy injuries, deaths, or property damage and year shown in sub-bullets, since 2000 in Napa County, the smallest reportable region. ▪ 110 days with high wind events
o January of 2010 saw almost $1 million in damages
o $3.25 million in total damage since 2000
o Three reported deaths and five reported injuries
▪ 11 heavy rain events
o $250,000 in property damage since 2000
o January 1, 2002 saw $100,000 in property damages
▪ 5 days with high heat events
o Both 2019 and 2020 saw high heat events
o One death since 2000
o Note this number does not include the summer of 2021
4.5.7.3 Location
Extreme weather events have the potential to happen anywhere in the planning area. Wind events are most damaging to areas that are heavily wooded. Heavy rain events can be more impactful in more populous areas with greater impervious surfaces. The following figures show average weather conditions for Napa:
▪ Figure 4-47: City of Napa - Average Annual Precipitation ▪ Figure 4-48: City of Napa - 30-Year Normal Maximum Temperature for July ▪ Figure 4-49: City of Napa - Annual Average Wind Speed (Power Class). Table 4-61 further explains the classes of wind power density shown in Figure 4-49.
4.5.7.4 Frequency and Probability of Future Events
Extreme weather events since the year 2000 have caused a total of $205,000 worth of property damage in Napa County, the smallest reportable region. Extreme weather events occur annually in Napa County to a varying degree, not always with property damage involved.
High Wind: Figure 4-49 displays average annual wind speeds by power class in the City of Napa and Table 4-61 describes wind power classes.
Heavy Rain: Figure 4-47 depicts the average annual precipitation from 1981 through 2010. Even if overall precipitation does not significantly depart from average in the future, heavy rainfall events are predicted to increase with climate change. (United States Geological Survey, n.d.) High Heat: Figure 4-48 shows the average maximum temperature for Napa in July. As discussed in more detail herein, climate change is predicted to increase the frequency of high heat events in the future. 1-26-2022 Submittal EXHIBIT A Page 221 of 416
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Figure 4-47: City of Napa - Average Annual Precipitation 1-26-2022 Submittal EXHIBIT A Page 222 of 416
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Figure 4-48: City of Napa - 30-Year Normal Maximum Temperature for July 1-26-2022 Submittal EXHIBIT A Page 223 of 416
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Figure 4-49: City of Napa - Annual Average Wind Speed (Power Class) 1-26-2022 Submittal EXHIBIT A Page 224 of 416
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Table 4-61: Classes of Wind Power Density at 10 m and 50 ma 10 m (33 ft) 50 m (164 ft)
Wind Power Class
Wind Power Density
(W/m2) Speedb m/s (mph)
Wind Power Density
(W/m2) Speedb m/s (mph)
1 0 0 0
100 4.4 (9.8) 200 5.6 (12.5)
2 150 5.1 (11.5) 300 6.4 (14.3)
3 200 5.6 (12.5) 400 7.0 (15.7)
4 250 6.0 (13.4) 500 7.5 (16.8)
5 300 6.4 (14.3) 600 8.0 (17.9)
6 400 7.0 (15.7) 800 8.8 (19.7)
7 1000 9.4 (21.1) 2000 11.9 (26.6)
a Vertical extrapolation of wind speed based on the 1/7 power law. b Mean wind speed is based on Rayleigh speed distribution of equivalent mean wind power density. Wind speed is for standard sea-level conditions. To maintain the same power density, speed increases 3%/1000 m (5%/5000 ft) elevation.
NOTE: Each wind power class should span two power densities. For example, Wind Power Class = 3 represents the Wind Power Density range between 150 W/m2 and 200 W/m2. The offset cells in the first column attempt to illustrate this concept.
4.5.7.5 Severity and Extent
The most common problems associated with high wind and heavy rain are immobility and loss of utilities.
Fatalities are uncommon but can occur. Roads may become impassable due to flooding, downed trees, or a landslide. Power lines may be downed due to high winds, and services such as water or phone may not be able to operate without power.
High Wind: Windstorms can be a problem in the planning area and could cause damage to utilities. It is important to note that the predicted wind speed given in wind warnings issued by the National Weather Service is for a one-minute average; gusts may be 25 to 30 percent higher. High wind events have become more impactful in the past years because they trigger Public Safety Power Shutoff (PSPS) events regionally and are major drivers of wildfire spread.
Heavy Rain: Heavy rain has been a problem in the City of Napa and could cause future damage to facilities and utilities in the planning area. From 2000 to 2021, heavy rain events were the most common form of extreme weather, resulting in property damage for five out of the 12 recorded events. While recent projects have reduced the overall severity and extent of flooding in key parts of Napa, such as the downtown area, heavy rain events still trigger flooding around the city. 1-26-2022 Submittal EXHIBIT A Page 225 of 416
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High Heat: High heat has been a problem in the City of Napa in the past and will likely cause future damage to facilities, utilities, and residents in the planning area. Climate change will exacerbate high heat extremes within the city.
4.5.7.6 Warning Time
High Wind: Meteorologists can often predict the likelihood of high winds, which can give several days of warning time; however, meteorologists cannot predict the exact time of onset or severity of high winds.
Some storms may come on more quickly and have only a few hours of warning time. A Red Flag Warning is issued when warm temperatures, very low humidity, and stronger winds are expected to combine to produce an increased risk of fire danger. (National Weather Service) Heavy Rain: As with high winds, meteorologists can often predict the likelihood of a storm with heavy rains. This can give several days of warning time; however, meteorologists cannot predict the exact time of onset or severity of heavy rain, or the precise locations of heavy rainfall. Some storms may come on more quickly and have only a few hours of warning time.
High Heat: Meteorologists can often predict the likelihood of high heat weeks in advance by monitoring ocean temperatures and world-wide weather patterns. The City of Napa offers extreme weather, including heat emergency warnings, on their civic alerts webpage, including links for obtaining information on extreme heat forecasts. Interested individuals can also sign up for emergency alerts from the same webpage.
4.5.7.7 Secondary Hazards
High Wind: The most significant secondary hazards associated with high winds are falling and downed trees, downed power lines, and wildfire. High winds can cause damage to properties and destruction of roadways and they can magnify wildfires and increase their rate of spread.
Heavy Rain: The most significant secondary hazard associated with heavy rains is flooding, which can also cause falling and downed trees, landslides, and downed power lines. Heavy rain can cause damage to properties and destruction of roadways. Landslides occur when the soil on slopes becomes oversaturated and fails. Flooding is further analyzed in Section 4.5.6.
High Heat: High heat can dry out local vegetation, thus contributing to an increase in vegetative fuels and wildfire threat.
4.5.7.8 Climate Change
The effects of climate change are diverse and include warmer and more varied weather patterns, such as melting ice caps and poor air quality. As a result, climate change will likely worsen a number of natural hazards, including extreme weather. The effects of climate change on extreme weather are most likely to create more frequent and prolonged periods of extreme heat. However, climate change will result in 1-26-2022 Submittal EXHIBIT A Page 226 of 416
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unpredictable temperature fluctuations that could lead to freezing events during the warmer months of the year, which could have a devastating effect on agriculture. (United States Environmental Protection Agency, 2016)
High Wind: Climate change is expected to increase the frequency and severity of high winds in areas in and near the City of Napa. (Ackerly, 2018)
Heavy Rain: The number of extreme precipitation events by water year is expected to increase in and near the City of Napa under RCP 4.5 and 8.5 scenarios. (Cal-Adapt, 2021) High Heat: Currently, the average annual number of consecutive days of extreme heat in the City of Napa is four days at a temperature of 99.1°F. Model projections for the longest stretch of consecutive extreme heat days per year, under an RCP 8.5 scenario and at a temperature at or above 99.1°F in the City of Napa, predict an average of 22 days per year during the years 2070 to 2099. (Cal-Adapt, 2021)
4.5.7.9 Extreme Weather Vulnerability Analysis
Population
It can be assumed that the entire planning area is exposed to extreme weather events to some extent.
Certain areas are more exposed due to geographic location and local weather patterns. Populations living at higher elevations with large stands of trees or overhead power lines may be more susceptible to wind damage and blackout.
Vulnerable populations, such as the elderly, low income, linguistically isolated, or people with lifethreatening illnesses, may become isolated from major roads and emergency services in extreme weather events. Power outages can be life-threatening to those dependent on electricity for life support. These populations face isolation and exposure during extreme weather events and could suffer more secondary effects of the hazard; therefore, vulnerable populations are of particular concern.
High Wind: High wind can impact the mobility of vulnerable populations, notably the elderly and people with disabilities. Associated impacts from downed power infrastructure can also negatively impact these populations, many of whom rely on power for life support.
Heavy Rain: Heavy rain can pose a similar risk to vulnerable populations as high wind. In addition, heavy rain can limit mobility, decrease visibility, and isolate people who might live more remotely.
High Heat: High heat can be dangerous for vulnerable populations and even fatal, especially for the elderly or very young. Extreme heat is associated with cardiovascular and respiratory disorders, as well as heat stroke. End of century predictions for annual average maximum temperatures in the City of Napa depict an increase in temperature of 4.5°F and 7.4°F under RCP 4.5 and 8.5 scenarios, respectively. (Cal-Adapt, 2021)
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Property
All property is vulnerable during extreme weather events, but properties in poor condition or in particularly vulnerable locations may risk the most damage. Those in higher elevations and on ridges may be more prone to wind damage. Property located under or near overhead power lines or near large trees may be vulnerable or may be damaged in the event of a collapse. Crops may be damaged by high wind or heavy rain.
High Wind: High winds can cause significant property damage. Associated impacts to property include roofs being blown off, trees and branches falling onto property, fences being blown down, and large infrastructure falling onto property.
Heavy Rain: Heavy rain can also cause extensive property damage. It can flood properties and cause secondary impacts, such as waterlogged branches or trees falling onto property.
High Heat: High heat can cause property damages in some cases. High temperatures can cause roofs to expand and warp and can weaken the structural integrity of buildings.
Critical Facilities and Infrastructure
All critical facilities exposed to flooding are also likely exposed to extreme weather. Additional facilities on higher ground may also be exposed to wind damage or damage from falling trees. The most common problems associated with extreme weather is the loss of utilities. Downed power lines can cause blackouts, leaving large areas isolated and phone, water, and sewer systems inoperable. Roads may become impassable due to flooding, downed trees, or landslides.
High Wind: High winds can knock down critical infrastructure, such as powerlines, which can prevent communication systems from functioning sufficiently. Severe winds can also cause structural and nonstructural damage to critical facilities.
Heavy Rain: Heavy rains, especially when accompanied by a windstorm, can cause water damage to critical facilities, compromising their functionality.
High Heat: High heat can impact the performance of critical facilities, especially ones which provide emergency services such as hospitals. Hospitals rely on well-regulated air temperatures and may not have the capacity to deal with extreme temperatures. Additionally, high temperatures can cause materials to expand, such as concrete and asphalt. This can cause infrastructure like sidewalks to expand and buckle at points where two pieces of concrete or asphalt meet each other. (Federal Highway Administration, 2013) Lifelines
Loss of roads or power and communication lines are the primary lifeline failures resulting from extreme weather and are mostly due to secondary hazards, such as floods, falling and downed trees, landslides, and 1-26-2022 Submittal EXHIBIT A Page 228 of 416
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wildfire. Prolonged obstruction of major transportation routes can disrupt the shipment of goods and other commerce, and large, prolonged storms can have negative economic impacts on an entire region.
High Wind: Severe windstorms and downed trees can create serious impacts on power and above-ground communication lines. Loss of electricity and phone connections would leave certain populations isolated because residents would be unable to call for assistance. High winds can also cause significant damage to trees and power lines, blocking roads with debris, damaging transportation infrastructure, isolating populations, and disrupting ingress and egress routes.
Heavy Rain: Heavy rains can cause secondary hazards, such as landslides and floods, and can cause trees to fall. These secondary hazards can compromise roads and power and communication lines.
High Heat: High heat can cause transmission lines to function less efficiently. The combination of an increase in demand and warmer air can cause the lines to swell and, consequently, compromise parts of the infrastructure. (US Department of Energy, 2019, p. 12) Future Trends in Development
All future development will be affected by severe storms. The ability to withstand impacts lies in sound land use practices and consistent enforcement of codes and regulations for new construction. The City of Napa has adopted the California Building Code, which corresponds to the International Building Code, to meet California mandates. This code is equipped to deal with the impacts of extreme weather events. Land use policies identified in general plans within the planning area also address many of the secondary impacts, such as flood and landslide, of the extreme weather hazard. With these tools, the city is well equipped to deal with future growth and the associated impacts of extreme weather.
Extreme Weather Hazard Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and extreme weather hazard data. Extreme weather problem statements for the City of Napa are listed in Table 4-62. 1-26-2022 Submittal EXHIBIT A Page 229 of 416
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Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. See Table 5-6 for a full list of mitigation actions and the corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-62 and Table 5-6.
Table 4-62: Extreme weather Problem Statements
Problem No.
Hazard
Type
Area of
Concern
Mitigation
Alternatives Problem Description Related MA
ps-EW-CN-34 Extreme
Weather
Impact PRV - Prevention ,
PPRO - Property
Protection , SP -
Structural Projects
Heavy rain events create localized flooding issues
around City infrastructure, posing a threat to
property and creating hazardous travel
conditions. Among many, the following areas
experience frequent flooding issues due to
insufficient drainage and/or undersized culverts:
Silverado / Trancas repetitive loss area (RLA); N
Napa off Valencia – between Jefferson, El Centro
and Solano Avenue.
ma-FL-CN-49,
ma-AH-CN-13
ps-EW-CN-35 Extreme
Weather
Impact PPRO - Property
Protection
Climate change is expected to increase the
frequency and severity of high wind events in the
City of Napa and surrounding areas.
ma-EW-CN-58
ps-EW-CN-36 Extreme
Weather
Impact SP - Structural
Projects
Backup generators are needed to maintain
continuity of City utilities and services during
severe weather events.
ma-AH-CN-57
ps-EW-CN-37 Extreme
Weather
Victim PRV - Prevention ,
PE&A - Public
Education &
Awareness , SP -
Structural Projects
High heat can cause serious human health
concerns, especially in homes without air
conditioning. Climate change is expected to
exacerbate these effects (see climate change
problem statements).
ma-CC-CN-51,
ma-AH-CN-57
ps-EW-CN-38 Extreme
Weather
Victim PRV - Prevention ,
PE&A - Public
Education &
Awareness
Mobile home populations, seniors, and homeless
populations are particularly susceptible to high
heat events.
ma-AH-CN-57,
ma-CC-CN-51
ps-EW-CN-39 Extreme
Weather
Threat PRV - Prevention ,
PPRO - Property
Protection
High winds exacerbate the threat of wildfire. ma-WF-CN-45 ps-EW-CN-40 Extreme
Weather
Threat PPRO - Property
Protection , SP -
Structural Projects
High winds can blow over trees and utility lines,
posing a hazard to life, property, drainage
systems, traffic and utilities.
ma-EW-CN-59
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4.5.8 Wildfire Hazard Profile
A wildfire is any uncontrolled fire occurring on undeveloped land that requires fire suppression. Wildfires can be ignited by lightning or by human activity, such as smoking, campfires, vehicle and equipment use, and arson. The 2018 California State Hazard Mitigation Plan defines wildfires as:
Any free-burning vegetative fire that initiates from an unplanned ignition, whether natural (e.g., lightning) or human-caused (e.g., powerlines, mechanical equipment, escaped prescribed fires), where the management objective is full suppression. (California Office of Emergency Services, 2018, p. 507) One of the primary causes of wildfire ignition are humans, accounting for nearly 85 percent of wildland fires in the United States. (Balch, et al., 2017) Human-caused fires can be directly attributed to unattended campfires, equipment use and malfunction, intentional acts of arson, and carelessly discarded cigarettes. (National Park Service, 2018) Humans also contribute to ignition patterns indirectly through land use changes, altered species composition, power line malfunction and climate change (Syphard, et al., 2019).
Wildfires are costly, putting lives and property at risk and compromising drinking water supplies, rivers and watersheds, open space, timber, range, recreational opportunities, wildlife habitats, endangered species, historic and cultural assets, scenic assets, and local economies. Vulnerability to flooding increases following a wildfire event due to the destruction of forest and ground cover within watersheds. The potential for significant damage to life and property increases in areas where development is adjacent to densely vegetated areas, known as the wildland-urban interface (WUI). (FEMA, 2020) While some fires are allowed to burn naturally in order to maintain or restore the health of forest lands, out of control wildfires need to be prevented through cooperative, community, and land management planning.
4.5.8.1 Local Conditions Relating to Wildfire
The City of Napa and its greater surroundings are characterized by a slender valley floor. The valley is interspersed with steep, hilly, wooded terrain and contains areas that are susceptible to wildfires. The hilly and mountainous terrain on the east and west sides of the Napa Valley strongly influences both wildfire behavior and the suppression capabilities of firefighters and their equipment. This area is most susceptible to wildfire impacts.
High wind is a leading factor in the spread of wildfire due to the increased scattering of burning embers, which are expeditiously carried with the wind to adjacent, exposed areas. The Napa Valley has a characteristic southerly wind that originates from the San Francisco Bay and becomes a factor to contend with in wildfire suppression. The valley also experiences an occasional north wind during the dry season.
This wind is of such significant velocity that it is recognized by fire fighters to be a significant factor in the spread of wildfires
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Steep slopes are land characteristics that also contribute to wildfire hazards by intensifying the effects of wind and making fire suppression difficult. Fires burn at a faster rate as they burn up-slope. Vegetation type also influences wildfire hazard risk and severity. For example, landscapes dominated by chaparral are more flammable than other vegetation types. The combination of highly flammable vegetation with steep, inaccessible wildlands and high levels of recreational use can result in increased wildfire risk and hazards of significant proportion. (Napa County, 2014)
Sudden Oak Death
The city is also at risk of increased wildfire due to what is referred to as sudden oak death. Sudden oak death is caused by the pathogen Phytophthora ramorum, which has been responsible for massive die-offs of true oak (Quercus spp.) and tanoak (Lithocarpus densiflorus) in coastal and inland regions of both California and Oregon, including Napa County. These die-offs become a source of fuel and have consequently become an increasing concern for their potential to increase fire intensity throughout the region. (Yana S. Valachovic et al., 2011) Climate change, more frequent droughts, and pathogen exposure are all risks necessary to consider when taking a proactive approach to ensuring long-term oak health and mitigating wildfire risk.
Wildland-Urban Interface and Urban Conflagration
Humans alter both fire ignition risk and fire behavior in the wildland-urban interface (WUI). As residential development in California has encroached on the WUI, wildfire risks have increased. The City of Napa is flanked by hilly, mountainous terrain on either side of the Napa Valley floor, with homes and communities enmeshed in heavily vegetated and sloped areas. Unique wildfire hazards specific to these areas include the proximity of homes and structures to vegetative fuels, increased ignition frequency, and delayed response times of firefighting resources due to accessibility limitations. The spread of larger wildfires into the built environment also poses a great risk of urban conflagration, which is the type of structure-tostructure spread in high density development areas that is implicated in massive losses from the Camp Fire in Butte County in 2018. (Syphard, et al., 2019)
De-Energization and PSPS Events
Recent wildfire events have been linked to faulty electric transmission equipment, which in turn has led to public safety power shutoffs (PSPS), also referred to as de-energization. (California Public Utilities Commission, 2020) Pacific Gas and Electric (PG&E) reached a $13.5 billion settlement and pled guilty to 84 counts of manslaughter as its transmission facilities sparked wine country blazes in 2017 and the fire that nearly destroyed the town of Paradise in 2018. (Blume, 2019) In order to avoid these catastrophic wildfire events, electric utility companies have started massive and preemptive power shutoffs in high wind events to avoid sparking fires. This leaves communities and essential facilities without power, a particular challenge in preparing for and responding to hazard events and assisting vulnerable populations. (California Public Utilities Commission, 2020) The increased frequency of PSPS events renewed focus on 1-26-2022 Submittal EXHIBIT A Page 232 of 416
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addressing the loss of power in hazard mitigation planning in the City of Napa and around the state, even as PSPS events grow more narrowly focused, creating less mass power losses in municipalities.
Extreme Fire Behavior
Extreme fire behavior is defined as “fire spread other than steady surface spread, especially when it involves rapid increases.” (Werth, et al., 2016) While local conditions, such as fuel, weather, and topography, determine initial fire spread and intensity, large wildfires can also generate their own weather patterns, triggering feedback loops of destruction. Recent “megafires” generate enough heat to produce updrafts measured in excess of 130 mph, sending giant plumes of smoke and moisture into the lower stratosphere where it condenses to form a pyrocumulonimbus cloud. (Rodriguez, Lareau, Kingsmill, & Clements, 2020) Under certain conditions, these wildfire-generated supercell storms can produce lightning, tornadostrength winds, and even actual tornadoes in some cases. This phenomenon of pyrotornadogenesis was documented in the 2018 Carr Fire and can be directly related to four deaths. (Lareau, Nauslar, & Abatzoglou, 2018) Extreme fire behavior associated with pyrocumulonimbus activity is also implicated in the wake of the destructive 2020 wildfire season in California. (Morris, 2021) As climate change drives an increase in the frequency and severity of wildfires, extreme fire behavior, including pyrocumulonimbus activity, is observed with greater frequency in proximity to population centers, posing risks to life and property. (Peterson, et al., 2021)
Extreme heat during extreme fire events increases erosion and water quality problems. After intense heating, a thin layer of soil at or below the soil surface may repel water completely (i.e., become hydrophobic). (Brooks, 2021) Reduced water infiltration in soils increases runoff and erosion and carries sediment that can clog stream channels and reduce water quality even to a point where rivers and streams temporarily cannot be used for drinking water supplies.
4.5.8.2 Plans, Policies, and Regulatory Environment
Wildfire Protection Responsibility in California
Local, state, tribal, and federal organizations all have legal and financial responsibility for wildfire protection. In many instances, two fire organizations have dual primary responsibility on the same parcel of land, one for wildfire protection and the other for structural fire protection. To address wildfire jurisdiction responsibilities, the California State Legislature outlined various wildfire responsibilities in 1981, described below, in Cal. Pub. Res. Code § 4291.5 and Cal. Health & Safety Code § 13108.5. ▪ Federal Responsibility Areas (FRAs): FRAs are fire-prone wildland areas that are owned or managed by a federal agency such as the U.S. Forest Service, National Park Service, Bureau of Land Management, U.S. Fish and Wildlife Service, or U.S. Department of Defense. Primary financial and rule-making jurisdiction authority rests with the federal land agency. In many instances, FRAs are interspersed with private land ownership or leases. Fire protection for developed private property is usually the responsibility of the relevant local government agency, not the federal land management agency. (California Department of Forestry and Fire Protection, 2013‐2018) 1-26-2022 Submittal EXHIBIT A Page 233 of 416
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▪ State Responsibility Areas (SRAs): SRAs are lands in California where the California Department of Forestry and Fire Protection (CAL FIRE) has legal and financial responsibility for wildfire protection. CAL FIRE administers fire hazard classifications and building standard regulations in these areas. SRAs are classified into types of land based on cover, beneficial use of water from watersheds, probable damage from erosion, and fire risks and hazards. (California Legislative Information, pp. § 4102, § 4130 ) CAL FIRE adopts SRA boundaries and updates them every 5 years.
Where SRAs contain structures or development, the relevant local government agencies have fire protection responsibility for those improvements. (Office of the State Fire Marshal, 2021) ▪ Local Responsibility Areas (LRAs): LRAs include land in cities, cultivated agriculture lands, unincorporated non-flammable areas, and lands that do not meet the criteria for SRA or FRA. LRA fire protection is typically provided by city or county fire departments, fire protection districts, or by CAL FIRE under contract to local governments. LRAs may still include areas of flammable vegetation and in the WUI. (Id.)
In 2012, as part of local general plan requirements, California began requiring local governments in SRAs and Very High Fire Hazard Severity Zones (VHFHSZ) to update their general plan safety elements to recognize specific wildfire risks in such areas and adopt special findings when approving subdivisions in such areas. Local governments are also required to use wildfire safety guidelines and California Environmental Quality Act (CEQA) initial study wildfire hazards checklist updates issued by the Governor’s Office of Planning and Research (OPR) when those become available. (Cal. Gov. Code § 65040.20 and § 65302.5)
For further information on the details and implications of these safety element requirements, see Progress Summaries 3.F and 8.A of the 2018 California State Hazard Mitigation Plan.
Healthy Forests Restoration Act (2003)
The federal Healthy Forests Restoration Act (HFRA) appropriates funding to address five main subcategories of the National Fire Plan (NFP): preparedness, suppression, reduction of hazardous fuels, burned-area rehabilitation, and state and local assistance to firefighters. The Napa County Community Wildfire Protection Plan (CWPP) has integrated these sub-categories through the following four best practices:
1. Identifying and prioritizing fuels reduction opportunities across the landscape;
2. Addressing structural ignitability;
3. Assessing community fire suppression capabilities; and
4. Collaborating with stakeholders.
California Fire Code (2019)
The City of Napa has adopted the 2019 edition of the California Fire Code to safeguard the public health, safety, and general welfare from the hazards of fire, explosion, and dangerous conditions in new and existing buildings and structures, on premises, and to provide safety and assistance to firefighters and 1-26-2022 Submittal EXHIBIT A Page 234 of 416
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emergency responders during emergency operations. Section 15.04.010 of the City of Napa Code adopts the California Fire Code and Section 15.04.080 provides city amendments to the California Fire Code.
California Building Code (2019)
The 2019 California Building Code, adopted by the City of Napa in 2019, includes materials and construction methods for exterior wildfire exposure and standards of quality for fire-resistant buildings. See California Building Codes, Chapter 7a (2019).
Title 24 California Code of Regulations
The California Building Standards Code, Title 24, which incorporates the California Fire Code, is adopted every three years by order of the California Legislature with supplements published in intervening years.
Title 24 mandates specific requirements for new building construction, placing strong emphasis on proper address signage, apparatus access, water requirements, and defensible space.
California Code, Public Resources Code § 4290
These regulations became effective in September of 1991 and require the future design and construction of structures, subdivisions, and developments in the SRA to provide for basic emergency access and perimeter wildfire protection measures (i.e., defensible space). These measures provide for emergency access, signing and building numbering, private water supply reserves for emergency fire use, and vegetation modification.
California Code, Public Resources Code § 4291
These regulations require property owners in mountainous areas, forest-covered lands, or any land that is covered with flammable material to create, at a minimum, a 100-foot defensible space buffer (or to the property line) around homes and other structures.
Napa Fire Department 2015-2020 Strategic Plan
The Napa Fire Department 2015-2020 Strategic Plan was developed for the City of Napa as a community driven stakeholder planning initiative. The plan includes a series of initiatives and associated objectives that are meant to increase the effectiveness of the Napa Fire Department. These include, but are not limited to, implementing information technology upgrades, identifying funding resources, and determining best practices.
Napa County Community Wildfire Protection Plan (2021)
The 2021 Napa County Community Wildfire Protection Plan (CWPP) was led by the Napa Community Firewise Foundation in collaboration with Napa County and CAL FIRE, with the goals of promoting interagency collaboration in the planning process and empowering local action on the part of both agencies and homeowners to mitigate wildfire risk county-wide. The CWPP establishes a shared vision of current wildfire risk, depicts emergency response capabilities, establishes a community outreach strategy, and identifies priority areas and makes recommendations for risk reduction. 1-26-2022 Submittal EXHIBIT A Page 235 of 416
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City of Napa General Plan
The 2015 City of Napa General Plan includes a number of goals, policies, and implementation actions in its Health and Safety, Natural Resources, and Community Services Elements to mitigate the effects of wildfires and reduce the risk to life and property. Relevant policies include measures for ensuring fire safe development, fire prevention and abatement programs, and a fire services plan. The city is currently updating its General Plan and will include wildfire safety and mitigation policies and programs as part of the update.
Fire Protection Features in City of Napa Code, §16.36.080 The City of Napa Code aids in reducing fire risks by ensuring the provision of protection features such as fire hydrants and sufficient emergency water capacity, flow, and storage in order to ensure the protection of the public health, safety, and welfare.
Provisions for Open or Outdoor Fires in City of Napa Code, §12.36.030 The City of Napa Code provides regulations for all open or outdoor fires within the boundaries of any city park. It is unlawful for any person to build, light, kindle, or maintain any open or outdoor fire unless acting within compliance of written authorization from the city and Fire Safety Official, or the person is acting in accordance with signs that are posted by the city authorizing outdoor fires within designated areas or facilities, such as a fire for food preparation within a specified barbeque area.
4.5.8.3 Past Events
From 2000 to 2020, there were eight wildfires near the City of Napa, each burning over 10 acres. These events are listed in Table 4-63 and displayed in Figure 4-51. Other even larger wildfires have occurred in Napa County over the years, especially in 2020, that are outside of Figure 4-51. Although these fires did not occur in close proximity to the City of Napa, they are discussed in the Recent Large Wildfire Events section in relation to their impacts to the city.
Table 4-63: Wildfire Events Near the City of Napa 2000-2020 Date Name Size in Acres
2008 Kelly 33
2008 Wild 4,102
2013 Amigas 10
2017 Redwood 14
2017 Nuns 55,798
2017 Atlas 51,625
2017 Rockville 23
2018 Syar 10
Source: CAL FIRE Incident Database (2021)
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Recent Large Wildfire Events
LNU Lightning Complex (2020)
The LNU Lightning Complex
was a series of lightningsparked fires, most initially small, that began in August
and continued through
October of 2020 in Napa
County among others. The
Hennessey Fire was one of
the complex that extended
along a north-south
longitude through the
eastern portion of Napa
County and into Yolo and
Solano Counties, threatening
and damaging areas related
to the city’s major water
supply, Lake Hennessey. The
Hennessey Fire grew and
merged with the Gamble,
Green, Markley, Spanish, and Morgan Fires to burn around 192,000 acres. In total, the LNU Lightning Complex fires burned 363,220 acres and were active for 46 days from August 17, 2020 to October 2, 2020.
There were five injuries and five fatalities, and the fires damaged 232 structures and destroyed another 1,491. A total of 680 personnel and 19 firefighting crews were assigned to the LNU Lightning Complex fires. (CAL Fire, 2020) See Figure 4-50 for an image of the Hennessey Fire.
Atlas Fire, Tubbs Fire, and Patrick Fire (2017)
The October 2017 Northern California wildfires, also known as the Northern California firestorm, North Bay Fires, and Wine Country Fires, were a series of 250 wildfires that started burning across California. The fires broke out in Napa, Lake, Sonoma, Mendocino, Butte, and Solano Counties during severe fire weather conditions. (Nix, 2017) The Atlas, Tubbs, and Patrick Fires started on October 8, 2017 in Napa County and together damaged over 1,110 structures and destroyed more than 5,756. (Cal Fire, 2018). At the time, the Tubbs Fire was the most destructive wildfire in California history, burning parts of Napa, Sonoma, and Lake Counties and inflicting its greatest losses in the City of Santa Rosa. Its destructiveness was surpassed only a year later by the Camp Fire of 2018. See Figure 4-51 for locations of these historic fires.
Figure 4-50: Wildfire Conflagration
Photo: Jean Beaufort, Public Domain
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Figure 4-51: Historic Fire Perimeters Near the City of Napa 1-26-2022 Submittal EXHIBIT A Page 238 of 416
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4.5.8.4 Frequency and Probability of Future Occurrences Generally, the City of Napa faces a wildfire threat annually. Fire conditions arise from a combination of hot weather, an accumulation of vegetation, and low moisture content in the air. These conditions, exacerbated with high winds and years of drought, increase the potential for a wildfire to occur. Urban wildfires often occur in those areas where development has expanded into the rural areas. A fire along this urban-rural interface can result in major losses of property and structures. There are three major factors that sustain wildfires and allow for predictions of a given area’s potential to burn: fuel, topography, and weather.
Fuel is the material that feeds a fire and is a key factor in wildfire behavior. Fuel is generally classified by type and by volume. Fuel sources are diverse and include everything from dead tree needles, leaves, twigs, and branches to dead standing trees, live trees, brush, and cured grasses. Man-made structures and other associated combustibles are also considered fuel sources. The type of prevalent fuel in an area directly influences the behavior of wildfire. Light fuels, such as grasses, burn quickly and serve as a catalyst for fire spread. The volume of available fuel is described in terms of fuel loading. Certain areas in and surrounding the City of Napa and Napa County are extremely vulnerable to fires as a result of dense, grassy vegetation combined with a growing number of structures being built near and within the wildland-urban interface (WUI).
An area’s topography also affects its susceptibility to wildfire spread. Fire intensities and rates of spread increase as slope increases due to the tendency of heat from a fire to rise via convection. Where fire quickly spreads up a canyon, gully, or other similarly constrained topographic feature, this is referred to as the “chimney effect.” The natural arrangement of vegetation throughout a hillside can also contribute to increased fire activity on slopes.
Weather components, such as temperature, relative humidity, wind, and lightning, also affect the potential for wildfire. High temperatures and low relative humidity dry out the fuels that feed the wildfire creating a situation where fuel will more readily ignite and burn more intensely. Wind is the most treacherous weather factor. The greater a wind, the faster a fire will spread and the more intense it will be. Winds can be significant at times in Napa. In addition to high winds, wind shifts can occur suddenly due to temperature changes or the interaction of wind with topographical features, such as slopes or steep hillsides. Related to weather is the issue of recent drought conditions contributing to concerns about wildfire vulnerability. During periods of drought, the threat of wildfire increases. (NOAA, 2018) Wildfire return intervals, shown in Figure 4-52, illustrates the average period between wildfires under the historical wildfire regime. This can be helpful guidance as to the frequency and probability of future occurrence, which historically occurred through most parts of what is now the City of Napa every 16-25 years. Frequency of wildfire events may increase because of increasingly drier conditions caused by climate change. Fire risk will also continue to grow as more people build in WUI areas, which increases fuel loads and the risk of human-caused fires. (FEMA, 2020) 1-26-2022 Submittal EXHIBIT A Page 239 of 416
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Figure 4-52: City of Napa Mean Wildfire Return Intervals 1-26-2022 Submittal EXHIBIT A Page 240 of 416
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4.5.8.5 Severity and Extent
The severity of the wildfire hazard is determined by the relationship between three factors: fuel classification, topographic slope, and critical fire weather frequency. The City of Napa has a medium amount of wildfire fuels and the area typically experiences critical fire weather conditions two to seven days annually. Critical fire weather conditions, referred to as Red Flag Warnings, occur in periods of relative low humidity, high heat, and high winds.
Wildfire extent is best understood as the strength or magnitude (a.k.a. the severity) of the wildfire. While potential wildfires will vary, the best way to understand wildfire extent is through wildfire severity mapping. See Section 4.5.8.5.1.
The extent of wildfire can vary greatly based on the severity of the wildfire or cumulative effects of multiple wildfires to the city. . . TO BE CONTINUED post-discussion. . .
Human health impacts in the city increase if the wildfire event is greater in severity and extent or given multiple wildfire events impacting the city. Smoke and air pollution from wildfires can be a health hazard, especially for sensitive populations such as children, the elderly, and those with respiratory or cardiovascular diseases. Wildfire may also threaten the health and safety of those fighting the fires. First responders are exposed to the dangers from the initial incident and after-effects from smoke inhalation and heat stroke. In addition, wildfire can lead to ancillary impacts, such as landslides in steep ravine areas and flooding due to the impacts of silt in local watersheds.
Composite Wildfire Severity Mapping
Wildfire severity mapping in this HMP compiles data from three different sources to provide a composite wildfire severity overlay depicting moderate wildfire hazard in the WUI areas of the City limits, as well as high and very high wildfire severity near City boundaries. Mapping layers are depicted in Figure 4-53. The composite of the wildfire layers is then shown in Figure 4-54.
CAL FIRE WUI and Tree Mortality
The CAL FIRE tree mortality data set identifies and maps areas that pose the greatest threat to populations, parcels, and critical infrastructure because of instances of tree mortality. These areas are identified as “high hazard zones,” and CAL FIRE prioritizes tree removal in these areas. Figure 4-53 identifies areas of moderate tree mortality surrounding the City. (CAL FIRE, 2021) The CAL FIRE Wilderness Urban Interface (WUI) dataset identifies potential treatment zones in which projects could be conducted to reduce wildfire threats to people. Significant amounts of the interior of the city boundary, as well as areas immediately surrounding the boundary, are classified as the “WUI Influence Zone” or the first of three levels of WUI severity. Figure 4-53 illustrates this risk as “moderate.” The WUI Influence Zone is characterized by wildfire susceptible vegetation up to 1.5 miles from the WUI Interface, which is the most severe WUI categorization comprised of dense housing adjacent to vegetation that can 1-26-2022 Submittal EXHIBIT A Page 241 of 416
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burn in a wildfire. The WUI Intermix, the second level of WUI severity, is housing interspersed with wildland vegetation. (CAL FIRE, 2019)
California Public Utilities Commission (CPUC) Fire Threat Tier The CPUC Safety and Enforcement Division identifies “High Fire-Threat Districts,” or HFTDs, throughout California, where a higher risk for power line fires igniting and spreading exists. Some PCUC regulations apply only in these HFTDs. Districts are further divided into classes one through three, with three being the highest wildfire severity. (CPUC, 2021) Figure 4-53 depicts the highest severity,tier three, as “very high” and tier two as “high” wildfire severity.
Fire Hazard Severity Zones (FHSZs)
CAL FIRE establishes and maps Fire Hazard Severity Zones (FHSZ), or areas of significant fire hazards based on factors such as fuel, weather, terrain, and the number of days of moderate, high, and extreme fire hazard. These zones define the application of various mitigation strategies to reduce the risk associated with wildfires.
The FHSV model inputs frequency of fire weather, ignition patterns, expected rate of spread, and past fire history. It also accounts for flying ember production based on the area of influence where embers are likely to land and cause ignitions. The FHSZ model is built from existing data and hazard constructs and, thus, does not necessarily take into consideration significant land use and structural resiliency. The geography, weather patterns, and vegetation in the planning area provide ideal conditions for recurring wildfires. 1-26-2022 Submittal EXHIBIT A Page 242 of 416
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Figure 4-53: Data Sources for Composite Wildfire Severity in the City of Napa 1-26-2022 Submittal EXHIBIT A Page 243 of 416
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Figure 4-54: City of Napa Wildfire Risk Exposure
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4.5.8.6 Warning Time
Regardless of the circumstances around the start of a wildfire, response time can be rapid and warning time short. Wildfires are often caused by humans, intentionally or accidentally. There is no way to predict when one might occur. The Fourth of July can be a time of heightened concern and outreach around wildfires since fireworks can cause fires and usage is high. Dry seasons and droughts greatly increase fire likelihood and lightning from dry thunderstorms may trigger wildfires. Extreme weather can be predicted, so special attention can be paid during weather events that may include lightning or wind events. Reliable National Weather Service lightning warnings are available on average 24 to 48 hours prior to a significant electrical storm.
There is also continued focus on more rapid detection and alert systems for wildfires. ALERTWildfire is a partnership of three universities: The University of Nevada, Reno (UNR), University of California San Diego (UCSD), and the University of Oregon (UO). The effort provides access to state-of-the-art Pan-Tilt-Zoom (PTZ) fire cameras discover, locate, and confirm fire ignition and ongoing fire behavior. The camera system has been used as a resource in many recent large wildfires in California, including the 2020 LNU Lightning Complex fires. Cameras continue to be placed throughout California, with the goal of placing 1,000 cameras in California by 2022. Cameras may be installed by federal agencies, utilities such as PG&E, state emergency services such as CAL FIRE, local governments, and NGOs. (ALERTWildfire, 2021) If a fire does break out and spread rapidly, residents may need to evacuate within days or hours. A fire’s peak burning period is generally between 1 p.m. and 6 p.m. Once a fire has started, fire alerting is reasonably rapid in most cases. The rapid spread of cellular and two-way radio communications in recent years has contributed to a significant improvement in warning time. (California Fire, 2020) The City of Napa and Napa County coordinate emergency warnings through Nixle and wireless emergency alerts (WEA).
4.5.8.7 Secondary Hazards
Wildfires can generate a range of secondary impacts, which in some cases may cause more widespread and prolonged damage than the fire itself. Fires can cause direct economic losses in the reduction of harvestable timber and indirect economic losses in reduced tourism and commerce. Wildfires can also cause contamination in reservoirs, destroy transmission lines, and contribute to flooding. They strip slopes of vegetation, exposing them to greater amounts of runoff, weakening soils, and causing slope failures. Major landslides can occur several years after a wildfire. Wildfires that burn hot and for long durations can bake soils, especially those with a high clay content, creating hydrophobic soils that repel water. When it rains in burned areas, more soil washes off the hills into roads, ditches, and streams and increases flooding. (United States Department of Agriculture, n.d.) 1-26-2022 Submittal EXHIBIT A Page 245 of 416
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4.5.8.8 Climate Change Impacts
Climate change has the potential to affect multiple elements of the wildfire system, including fire behavior, ignitions, fire management, and vegetation fuels. Hot, dry spells create the highest fire risk. Drought and increased temperatures intensify wildfire danger by warming and drying out vegetation. Climate change may also increase winds that spread fires. Faster fires are harder to contain and, thus, more likely to expand into residential neighborhoods Moreover, rain events are predicted to become more severe in our changing climate, and post-fire flooding could worsen as well. (Id.). (Center for Climate and Energy Solutions, n.d.)
Moreover, while the majority of past wildfire events in the City of Napa area were in the late summer months (typically June through October), with warming and drying lasting longer and growing more intense, the wildfire season is predicted to lengthen.
It is predicted that the City of Napa will see higher daily temperatures, more heatwaves, and increased wildfires within this century as a result of climate change. The western portion of the City of Napa, in particular, is projected to experience an increase in wildfire risk by 2085. (California Energy Commission, 2020)
4.5.8.9 Wildfire Vulnerability Analysis
This section describes vulnerabilities to wildfire in terms of population, property, and infrastructure.
Wildfire population, parcel value, critical facilities and lifeline exposure numbers were generated by overlaying the inventory outlined in Section 4.3 with CAL FIRE Wildfire Hazard Severity Zones.Figure 4-55 shows a snapshot of wildfire vulnerability in the City of Napa. All data sources have a level of accuracy acceptable for planning purposes. Details for each snapshot can be found in this section. 1-26-2022 Submittal EXHIBIT A Page 246 of 416
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Figure 4-55: City of Napa Exposure Wildfire Vulnerability and Snapshot Map 1-26-2022 Submittal EXHIBIT A Page 247 of 416
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Population
Smoke and air pollution from wildfires can be a severe health hazard, especially for sensitive populations such as children, the elderly, and those with respiratory or cardiovascular diseases. Smoke generated by wildfire contains visible and invisible emissions, including particulate matter such as soot, tar, water vapor, and minerals; gases such as carbon monoxide, carbon dioxide, and nitrogen oxides; and toxins such as formaldehyde and benzene. Emissions from wildfires depend on the type of fuel, the moisture content of the fuel, the efficiency or temperature of combustion, and the weather. Public and mental health impacts associated with wildfire include difficulty breathing, odor, reduction in visibility, depression, and anxiety.
Likewise, first responders are exposed to the dangers from the initial incident and after-effects from smoke inhalation and heat stroke.
Wildfire is of greatest concern to populations residing in the moderate, high, and very high Fire Hazard Severity Zones. See Figure 4-55, Figure 4-56, and Table 4-64 for detail on populations residing in wildfire risk areas. U.S. Census Bureau block data was used to estimate populations within the CAL FIRE identified hazard zones.
Table 4-64: Populations Exposed to Wildfire Risk
Total Population
City of Napa 79,722
Wildfire Severity Zone Population Count % of Total
Very High - 0.00%
High 64 0.08%
Moderate 49,338 61.89%
Total 49,403 61.97%
Figure 4-56: Population Exposed to Wildfire Risk
0 64
49,338
0 10,000
20,000
30,000
40,000
50,000
60,000
Very High High Moderate
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Property
This section calculates the considerable assets at risk of wildfire in moderate, high, and very high Fire Hazard Severity Zones. See Table 4-65, which utilizes Napa County parcel information to calculate exposure. In some cases, a parcel will be within multiple fire threat zones, and for this exercise every parcel with a square footage value greater than zero was developed in some way. Only improved parcels were analyzed.
Table 4-65: Residential Buildings and Content within Fire Hazard Severity Zones Total Parcels Total Market Value
($)
Total Content
Value ($) Total Value ($)
City of Napa 35,970 $13,766,988,459 $10,299,504,378 $24,066,492,838 Fire Hazard Severity
Zone Parcel Count % of Total Market Value Exposure ($)
Content Value
Exposure ($) Total Exposure ($) % of Total
Very High - 0.0% $0 $0 $0 0.0%
High 8 0.0% $5,955,901 $3,805,051 $9,760,952 0.0%
Moderate 23,309 64.8% $9,532,630,012 $7,159,006,547 $16,691,636,559 69.4% Total 23,317 65% $9,538,585,913 $7,162,811,598 $16,701,397,511 69.4% Critical Facilities and Infrastructure
Critical facilities of wood frame construction are especially vulnerable during wildfire events; power lines are also at risk from wildfire because some poles are made of wood and are susceptible to burning. In many cases, roads and railroads would not be susceptible to damage except in the worst scenarios, but a wildfire event could create response issues, if affected. Fires can create conditions that block or prevent access and can isolate residents and emergency service providers. Wildfire typically does not have a major direct impact on bridges, but it can create conditions in which bridges are obstructed. Many bridges in areas of high to moderate fire risk are important because they provide the only ingress and egress to large areas and, in some cases, to isolated neighborhoods.
Critical facilities data was overlain with Fire Hazard Severity Zone data to determine the type and number of facilities within each risk classification. Table 4-66 lists the critical facilities in hazard zones for the City of Napa, and Table 4-67 similarly lists critical infrastructure. 1-26-2022 Submittal EXHIBIT A Page 249 of 416
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Table 4-66: Critical Facility Exposure to Fire Hazard Severity Zones Infrastructure Type Very High High Moderate
Essential Facility**- - 5
Fire Station - - 3
Hospital - - 1
Police Station - - 1
High Potential Loss 1 4 227
Adult Residential Facility - - 4
Child Care Center - - 30
Church - - 31
Communication Tower - - 6
Dam - - 2
Farm Worker Housing - - -
Foster Family Agency - - 2
Historic Building - - 30
Home Care Organization - - 2
Library - - 3
*Real Property Asset 1 4 74
Residential Child Care - - 2
Residential Elder Care Facility - - 16
School - - 18
Stream Rain Gauges - - 6
Water Treatment Plant - - 1
Transportation and Lifeline - 4 163
Bridge - - 24
Power Plant - - 1
Pressure Regulator Station - - 12
Pump Station - 1 6
Sample Station - - 112
Substation - - 1
Water Tank - 3 7
Grand Total 1 8 395
*Real Property Assets are digitized insurance rolls for demonstrating value and ownership. ** Water Division facilities and infrastructure outside of the city boundaries are depicted on RAMP and are not included here. 1-26-2022 Submittal EXHIBIT A Page 250 of 416
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Table 4-67: Lifelines in Fire Hazard Severity Zones
Infrastructure Type (Linear) Very High High Moderate
Levee - - 2.14
Levee Centerline - - 1.23
Levee Flood Wall - - 0.98
NG Pipeline - - 10.65
Railroad - - 5.16
Street - 0.14 182.46
Alley - - -
Cul-de-sac - - 0.17
Driveway - 0.03 1.77
Interstate - - 2.44
Local road - - 11.67
Local road, major - 0.10 126.20
Primary highway - - 3.03
Ramp - - 2.54
Road, parking area - - 1.41
State/county highway - - 32.89
Thoroughfare, major - - 0.29
Traffic circle - - 0.05
Electric Transmission Line - - 11.04
Water Transmission Line - 0.44 23.86
Grand Total - 0.58 237.52
4.5.8.10 Changes in Development and Future Trends
Since the last HMP, overall changes in development have not impacted the City’s vulnerability to wildfire because of the City’s code requirements. The City’s municipal code references California wildfire construction standards, which are the strongest in the nation. The City of Napa Fire Prevention Division is responsible for the review and adoption of regulations relating to the control and prevention of fire. The division reviews development and building projects for compliance with applicable codes and standards and coordinates requirements with external and internal stakeholders. The division is also responsible for performing inspections of commercial and residential construction projects, performing weed abatement inspections, commissioning fire protection systems, investigating fire-hazard related complaints, investigating fires for the reason of determining their cause and origin, and the maintenance of building occupancy, which includes hotels, motels, apartments, schools, and assemblies. (City of Napa, n.d.) 1-26-2022 Submittal EXHIBIT A Page 251 of 416
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Fuel reduction projects are ongoing on federal, state, and private lands in the City of Napa. Such projects include vegetation management, broadcast burning, pre-commercial thinning, and the removal of dead, dying, and diseased trees. These projects have reduced and will continue to reduce vulnerability to wildfire in the areas where those projects are implemented.
4.5.8.11 Wildfire Problem Statements
As part of the mitigation action identification process, the Planning Committee for the city identified issues and weaknesses, also called problem statements, for its facilities. Identification was based on the risk assessment and vulnerability analysis utilizing the RAMP mapping tool and wildfire hazard data.
Wildfire problem statements for all planning committee are listed in Table 4-68.
Identifying these common issues and weaknesses assists the Planning Committee in understanding the realm of resources needed for mitigation. The goal is to have at least one mitigation action for every problem statement. See Table 5-6 for a full list of mitigation actions and the corresponding problem statements that they address. Each problem statement is coded with a problem number for crossreferencing between Table 4-68 and Table 5-6.
Table 4-68: Wildfire Problem Statements
Problem
No.
Hazard
Type
Area of
Concern
Mitigation
Alternatives
Primary
Agency Problem Description Related MA
ps-WF-CN-11 Wildfire Impact SP - Structural
Projects
City of
Napa
Napa wastewater treatment facility
requires additional defensible space to
protect from the impact of wildfire.
ma-WF-CN-43
ps-WF-CN12Wildfire Impact PRV -
Prevention
City of
Napa
Planning is needed to designate WUI
areas throughout the City to better
understand wildfire risk and potential
impacts.
ma-WF-CN-45,
ma-WF-CN-45,
ma-WF-CN-41,
ma-WF-CN-50,
ma-WF-CN-44,
ma-WF-CN-42,
ma-AH-CN-9,
ma-WF-CN-61
ps-WF-CN13Wildfire Impact SP - Structural
Projects
City of
Napa
City communication facilities and
towers and raw water pipeline
infrastructure are at risk of wildfire
impacts.
ma-AH-CN-0,
ma-WF-CN-42,
ma-WF-CN-63
ps-WF-CN14Wildfire Impact PRV -
Prevention
City of
Napa
Timberhill Park has an excess of
flammable fuels that could exacerbate
wildfire.
ma-WF-CN-50
ps-WF-CN15Wildfire Impact ES - Emergency
Services
City of
Napa
Timber Hill Park has access issues
affecting fire response.
ma-WF-CN-50
ps-WF-CN16Wildfire Threat PRV -
Prevention ,
NRP - Natural
Resource
Protection
City of
Napa
Lake Hennessey is susceptible to water
quality impacts post-wildfire.
ma-WF-CN-46,
ma-WF-CN-47,
ma-WF-CN-48,
ma-WF-CN-43
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Section 5. Mitigation Strategy
The mitigation strategy is the guidebook to future hazard mitigation administration for the city, capturing the key outcomes of the HMP planning process. The mitigation strategy is intended to reduce vulnerabilities outlined in the previous section with a prescription of policies and physical projects. These mitigation actions should be compatible with existing planning mechanisms and should outline specific roles and resources for implementation success. The Planning Committee conducted the hazard mitigation planning process through a typical process:
▪ Estimate the impacts (See Vulnerability Assessment);
▪ Describe the problem (See Problem Statement);
▪ Assess what resources exist to lessen impacts and problem (See Capability Assessment); ▪ Develop Goals and Objectives to address the problems (See Goals and Objectives); and ▪ Determine what can be done and develop actions that are appropriate for the community (See Mitigation Action Matrix).
5.1 Mitigation Alternatives
During Planning Committee Meeting #3 on June 24th, 2020, the HMP Planning Committee developed and reviewed mitigation actions with a wide range of alternatives, using FEMA’s six broad categories of mitigation alternatives described below. The HMP Planning Committee considered many mitigation alternatives for implementation under each mitigation category for the city. The City also met several times after the large group meeting to review specific hazard-related problem statements and develop mitigation actions. These meeting relied on the following framework to explore mitigation actions. 1-26-2022 Submittal EXHIBIT A Page 255 of 416
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PREVENTION (PRV)
Preventative activities keep hazard problems from getting worse and typically are administered through government programs or regulations addressing building and land development. Preventative actions are particularly effective in reducing a community’s future vulnerability in areas where development has not occurred, or capital improvements have not yet been substantial. Examples of preventative activities include:
▪ Planning and
zoning
ordinances
▪ Open space
preservation
▪ Stormwater
management
regulations
▪ Capital
improvements
programming
▪ Building codes ▪ Floodplain
regulations
▪ Drainage system
maintenance
▪ Riverine or fault
zone setbacks
LOCAL PRV ALTERNATIVE EXAMPLES
1. Establish ingress/ egress standards for future development.
2. Enhance the city’s GIS database and capabilities related to hazards information.
3. Maintain detention basins.
4. Conduct detailed study and mapping of floodplains for Napa River and its tributaries, targeting problematic floodplains.
5. Update and distribute wildfire risk mapping for the city.
6. Amend or revise water conservation regulations for landscape design for commercial and residential development with the goal of limiting outdoor watering. 1-26-2022 Submittal EXHIBIT A Page 256 of 416
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PROPERTY PROTECTION (PPRO)
Property protection measures involve the modification of existing buildings and structures to help them better withstand the forces of a hazard, or removal of the structures from hazardous locations. Examples include:
▪ Building elevation ▪ Retrofitting (e.g., seismic
design techniques, etc.)
▪ Insurance
▪ Critical facilities
protection
▪ Safe rooms, shutters,
shatter resistant glass
LOCAL PPRO ALTERNATIVE EXAMPLES
1. Continue to work with the Napa Communities Firesafe Foundation to conduct mitigation projects with homeowners. Provide homeowners easily accessible resources for mitigating the risk of wildfire around their homes.
2. Implement additional fuel reduction projects.
3. Remove existing structures from flood areas whenever and to the greatest extent possible; relocate farm work centers from flood risk areas.
4. Encourage privately owned critical facilities (e.g. churches, hotels, other gathering facilities) to evaluate the ability of the buildings to withstand earthquakes and to address any deficiencies identified.
5. Identify and harden critical lifeline systems (i.e., critical public services such as utilities and roads) to meet “Seismic Design Guidelines and Standards for Lifelines” or equivalent standards such as American Lifelines Alliance (ALA) guidance.
6. Continue participation in the Community Rating System and other ways to increase NFIP participation.
7. Review construction plans for all bridges to determine their susceptibility to collapse and retrofitting problem bridges.
8. Use flexible piping when extending water, sewer, or natural gas service.
9. Strengthening and retrofitting non-reinforced masonry buildings and non-ductile concrete facilities that are particularly vulnerable to ground shaking.
10. Install shutoff valves and emergency connector hoses where water mains cross fault lines.
11. Continue to incentivize drought-tolerant landscape design. 1-26-2022 Submittal EXHIBIT A Page 257 of 416
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PUBLIC EDUCATION AND AWARENESS (PE&A)
Public education and awareness activities advise students, staff, parents, nearby residents, and elected officials about hazards, hazardous areas, and mitigation techniques they can use to protect themselves and their property. Measures to educate and inform the public include:
▪ Outreach projects
including
neighborhood and
community
outreach
▪ Speaker
series/demonstration
events
▪ Real estate
disclosures
▪ School children
educational
programs
▪ Hazard mapping ▪ Materials library ▪ Hazard
expositions
LOCAL PE&A ALTERNATIVE EXAMPLES
1. Continue to work with the local Fire Safe Councils, educating homeowners on reducing the risk of wildfire on their property, including understanding their wildfire risk and free site visits.
2. Distribute public education materials relating to natural hazards as well as emergency notifications in both English and Spanish.
3. Partner with local water agencies such as the Napa Water Division, Friends of the Napa River, the Napa County Flood Control and Water Conservation District, etc., in their public education and conservation campaigns (in English and Spanish).
4. Encourage businesses to build financial reserves as part of economic development.
5. Improve floodplain management, earthquake preparedness, wildfire mitigation and preparedness, and other information on participating jurisdiction’s websites.
6. Distribute NFIP and floodplain development information in City libraries for access by the public.
7. Focus a public education program around neighborhoods with egress/ingress issues and narrow roads.
8. Improve interactive hazard mapping resources available to the public.
9. Develop a public information campaign on 72-hour kits.
10. Develop a "Natural Hazard Awareness Week" campaign and conduct corresponding outreach to the community and all interested parties.
11. Conduct outreach to builders, architects, engineers, and inspectors about building susceptibility to earthquakes and proper design and building requirements.
12. Educate on the importance of drought-tolerant landscaping, low flow indoor fixtures, and other water savings techniques to better withstand periods of drought.
13. Offer agricultural disaster training and networking opportunities for farmers and ag regulatory agencies.
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NATURAL RESOURCE PROTECTION (NRP)
Natural resource protection activities reduce the impact of natural hazards by preserving or restoring natural areas and their protective functions. Such areas include floodplains, wetlands, steep slopes, and sand dunes. Parks, recreation, or conservation agencies and organizations often implement these protective measures. Examples include:
▪ Floodplain protection ▪ Vegetation management
(e.g., fire resistant
landscaping, fuel breaks,
etc.)
▪ Wetland and habitat
preservation and
restoration
▪ Watershed management ▪ Erosion and sediment
control
LOCAL NRP ALTERNATIVE EXAMPLES
1. Protect and restore wetlands, riparian areas, and natural buffers to sea level rise, in particular continuing to implement restoration of Napa River.
2. Continue to participate in the Napa Countywide Stormwater Pollution Prevention Program and implement the Clean Water Act’s National Pollution Discharge Elimination System (NPDES) Phase II permit.
3. Complete vegetation management projects as prescribed in Napa Valley Community Wildfire Protection Plan.
4. Encourage and incentivize drought-tolerant landscape design.
5. Establish a priority list of slope failure locations and implement slope stabilization projects in the highest risk areas.
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EMERGENCY SERVICES (ES)
Although not typically considered a “mitigation”technique, emergency service measures do minimize the impact of a hazard event on people and property. These commonly are actions taken immediately prior to, during, or in response to a hazard event. Examples include:
▪ Warning systems ▪ Sandbag staging for flood protection ▪ Construction of evacuation routes ▪ Installing temporary shutters on buildings for wind protection
LOCAL ES ALTERNATIVE EXAMPLES
1. Construct/install back up power generators for fire stations, pump houses, emergency shelters, and cooling centers.
2. Develop a website for vulnerable populations to register information such as where the individual in question lives, medications, restrictions, etc. Map registrants or tie information to Nixle alert system.
3. Focus capital improvements on evacuation or emergency access routes needing attention.
4. Increase the capacity of existing hospitals through retrofits or upgrades such as isolation wings.
5. Construct or improve egress for wildfire emergencies in wilderness-urban interface (WUI) areas. 1-26-2022 Submittal EXHIBIT A Page 260 of 416
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STRUCTURAL PROJECTS (SP)
Structural mitigation projects are intended to lessen the impact of a hazard by modifying the environment and natural progression of the hazard event through construction. They are usually designed by engineers and managed or maintained by public works staff. Examples include:
▪ Stormwater diversions / detention /
retention infrastructure
▪ Utility Upgrades
▪ Seismic Retrofits
LOCAL SP ALTERNATIVE EXAMPLES
1. Improve water supply and delivery systems to be more resilient during times of drought.
2. Construct and develop alternative water supplies to augment single sources of water delivery.
3. Construct rainwater catchment systems to recharge groundwater in government ROWs.
4. Install water monitoring devices and drought-tolerant landscaping on government-owned facilities.
5. Improve stormwater drainage capacity; construct/improve stormwater basins City-wide to accomplish 100-year protection.
6. Construct, install, and maintain warning gauges on local dams as the opportunity or need arises.
7. Create an inventory and establish a priority list for culvert replacement that takes into account fish passage, flood depth reduction, and future losses avoided.
8. Continue to work with the Bureau of Reclamation to implement the Flood Control Project.
9. Retrofit critical care facilities with enhanced HVAC and isolation areas. 1-26-2022 Submittal EXHIBIT A Page 261 of 416
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5.2 Identifying the Problem
As part of the mitigation action identification process, the HMP Planning Committee identified the areas of concern and potential impacts of each of the identified hazards on the community. Developing these “problem statements” for areas of concern, which describe the nature of the consequences or effects of a hazard occurrence on the community and its assets, ensures the identified mitigation actions are tailored to the specific problems created by various hazard scenarios and are specific to the City of Napa. The City’s problem statements are available as part of the Mitigation Action Support Tool (MAST), which is summarized in Section 3, STEP 3: Develop a Mitigation Strategy, and they are available on mitigatehazards.com.
See Section 5.5.2 for City-wide mitigation actions.
5.3 Capabilities and Adaptive Capacity Assessment
This section examines the city’s planning and regulatory, administrative, technical, financial, educational, and outreach capabilities to augment known issues and weaknesses from identified natural hazards.
The capabilities assessment includes considerations of the city’s adaptive capacity for climate change, as outlined in Cal OES’ 2020 California Adaptation Planning Guide. Adaptive capacity is a community or region’s existing ability to moderate climate change impacts. Assessing adaptive capacity includes analysis of policies, plans, programs, funding, and staffing capacity. (Cal. Adaptation Planning Guide, 2020, p. 94)
The tables in this section explore various local planning mechanisms, administrative capacity, financial capabilities, and education and outreach initiatives. For more information on the regulatory environment surrounding each hazard, see hazard-specific sections of Section 4.5.
The columns in each table address following questions:
▪ Is the existing planning or regulatory mechanism used currently? (Column 1, Status) ▪ Has the HMP been integrated into the planning mechanism currently so that the named mechanism is currently used in HMP planning? (Column 2, Current Mitigation Use) ▪ Is there a future opportunity to expand, improve upon, and incorporate this 2020 HMP Update into the planning or regulatory mechanism? (Column 3, Future Opportunity) The capabilities assessment is easily-digestible and based on color coding to indicate which policies and plans are adequate, need improvement, or for which the HMP could be integrated. Each table includes a legend that explains how each one of these questions are being answered according to the color indicated:
green, yellow, or orange.
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5.3.1 Planning and Regulatory Mitigation Capabilities
The information in Table 5-1 is used to align mitigation actions with the existing planning and regulatory capabilities of the City. Planning and regulatory tools typically used by local jurisdictions to implement hazard mitigation activities are building codes, zoning regulations, floodplain management policies, and other municipal planning documents.
Table 5-1: City of Napa Planning and Regulatory Mitigation Capabilities
CAPABILITY ASSESSMENT LEGEND
Status Current Mitigation Use Future Opportunity
Currently in use or present. Used widely for mitigation. Opportunity to expand and integrate. (Sort of) Seldomly used or limited
presence.
Limited use in mitigation planning. Limited opportunity to expand and integrate. (No) Not present or available. Not used in mitigation planning. No opportunity to expand or integrate.
HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Planning and Regulatory Capabilities
Construction and Future Development Regulations
Building Codes Green Green Orange 2019 California Building Code Building Code Effectiveness Grading
Schedule (BCEGS) Rating Unknown at this time
Public Protection (ISO Class) Green Yellow Yellow Class 2 rating Hazard Related Development
Standards Green Green Yellow
Chapter 8.36 (Storm Water Quality Control);
New Development and Remodels (13.09.010);
Water Efficient Landscaping (17.52.520)
Hazard-Specific Ordinance
Green Green Yellow
Weed and Rubbish Abatement (Chapter 8.24);
Napa River/Napa Creek Flood Protection
Project Requirements (17.52.300)
Zoning Ordinance
Green Yellow Yellow
Discretion to reduce density allowance with
presence of physical hazards like landslides,
seismic faulting (17.08.050)
Growth Management Ordinance
Green Green Green Currently the Rural Urban Limit; General Plan update currently underway
Hazard Reduction Programs (Annually Conducted)
Capital Improvements Program (CIP) or
Plan Green Yellow Green Strong opportunity to better integrate hazard mitigation into CIP
Erosion/Sediment Control Program Green Green Yellow
Hazard-Related Public Outreach
Program Green Yellow Yellow See Education and Outreach Capabilitiies for more specifics
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Planning and Regulatory Capabilities
Stormwater Management Program
(Annual Inspections)
Green Green Yellow
City of Napa Final Storm Drainage Master Plan
(2006); Napa Countywide Stormwater Pollution
Prevention Program
(NCSPPP) (2014)
Seismic Safety Program (Nonstructural Inspections) Green Yellow Yellow Earthquake Modernization Program
(Building Safety Inspections) Green Yellow Yellow
Hazard Plans
General Plan Safety Element
Green Green Green
City of Napa General Plan includes Health and
Safety element (adopted 1998 updated 2015);
currently being updated.
Noteworthy Area/ Specific Plan with
Hazard Focus Green Yellow Green
Sonoma-Lake-Napa Unit 2020 Strategic Fire
Plan; Napa Fire Department Strategic Plan
(2015-2020)
Community Wildfire Protection Plan
(CWPP) Green Green Yellow The Napa County Community Wildfire Protection Plan (2021) includes City of Napa
Wildfire Vulnerability Assessment N/A N/A Green CWPP reflects most recent effort Urban or Integrated Regional Water
Management Plan Green Yellow Yellow City of Napa Urban Water Management Plan (2015; currently being updated)
Floodplain Management Plan
Green Green Yellow
Napa River Flood Management Plan (Napa
Flood Control and Water Conservation District);
The City of Napa Development Engineering
houses the City's Floodplain Management
Program
Stormwater Management Plan Green Yellow Green City of Napa Storm Drainage Master Plan (2006) Ground Water Management Plan(s)
Orange Orange Yellow
Napa County Groundwater Sustainability Plan
covers the Napa Valley Subbasin which
includes the City of Napa (still in development)
Open Space and Land Management
Plan(s) Yellow Yellow Green Parks and Recreation Element of GP (currently being updated)
Emergency Operations Plan
Green Green Orange City of Napa EOP (2018); City of Napa also part of operational area for Napa County EOP (2020)
Climate Action Plan, Vulnerability
Ass'mt, or Adaptation Plan
Yellow Yellow Green
City of Napa Sustainability Plan (2012); Napa
County Climate Action Plan (2018) includes
resources for the City of Napa; Napa Valley
Drought Contingency Plan (ongoing)
Sustainable Community Plan (SB 375) Green Yellow Yellow Through the Ass'n of Bay Area Gov'ts (ABAG) Local Delta/ Wetlands Program(s)
Green Green Green Napa Wetlands Monitoring Program Final Report (2007)
Downtown Plan with hazard focus
Green Yellow Green City of Napa Downtown Specific Plan (2012) with flood discussion
Community Health Assessment(s) Yellow Yellow Yellow Napa County Comprehensive Community Health Assessment (2013)
National Flood Protection Program (NFIP)
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HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Planning and Regulatory Capabilities
Floodplain Management Regulations
Green Green Yellow Floodplain Management Regulations for the Floodway (17.38.080)
Flood Insurance Education and
Technical Assist. Green Green Yellow Napa City webpage includes flood insurance information
Flood Hazard Mapping / Re-Mapping
Green Yellow Green
Napa City webpage includes maps of flood
inundation areas, one of which is interactive;
some repetitive loss areas are ready to be
removed from mapping and desigation
Community Rating System (CRS) Green Green Yellow CRS entry date: 05/01/01
5.3.2 Financial Capabilities
Table 5-2 identifies the financial tools or resources that the City has used to fund mitigation activities.
Table 5-2: City of Napa Fiscal Capabilities Summary
CAPABILITY ASSESSMENT LEGEND
Status Current Mitigation Use Future Opportunity
Currently in use or present. Used widely for mitigation. Opportunity to expand and integrate. (Sort of) Seldomly used or limited
presence.
Limited use in mitigation planning. Limited opportunity to expand and integrate. (No) Not present or available. Not used in mitigation planning. No opportunity to expand or integrate.
HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Fiscal Capabilities
Financial Resources for Hazard
Mitigation
Levy for Specific Purposes with Voter
Approval Yellow Yellow Green
Utilities Fees Green Yellow Yellow
Benefit assessments Yellow Yellow Green
System Development Fee Green Yellow Green
Various Bonds to Incur Debt Green Green Yellow
Stormwater Service Fees
Orange Orange Yellow There is a very limited opportunity to create such a fee at this time.
Capital Improvement Project Funding Green Green Yellow
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5.3.3 Education and Outreach
Table 5-3 lists the education and outreach opportunities either at the city level or available to city residents.
Table 5-3: City of Napa Education/ Outreach Capabilities Summary
CAPABILITY ASSESSMENT LEGEND
Status Current Mitigation Use Future Opportunity
Currently in use or present. Used widely for mitigation. Opportunity to expand and integrate. (Sort of) Seldomly used or limited
presence.
Limited use in mitigation planning. Limited opportunity to expand and integrate. (No) Not present or available. Not used in mitigation planning. No opportunity to expand or integrate.
HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Education / Outreach Capabilities
Education/Outreach Resources
Website Dedicated to Hazard Topics Green Green Green
Dedicated Social Media Green Yellow Green Facebook page Hazard Info. Avail. at Library/ Planning
Desk Green Green Yellow
Annual Public Safety Events
Yellow Yellow Yellow
Yes, during regular business operations (not
possible currently because of COVID
restrictions)
Ability to Field Public Tech. Assistance
Requests Green Green Green
Public Safety Newsletters or Printed
Outreach Green Yellow Yellow General Plan Newsletter
Fire Safe Councils
Green Green Green Napa Communities Firewise Foundation and 12 Fire Safe Councils
Resource Conservation Districts Yellow Yellow Green Napa County Resource Conservation District Other 0 0 0
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5.3.4 Administrative and Technical Capabilities
Table 5-4 shows the administrative and technical capabilities of the City of Napa.
Table 5-4: City of Napa Administrative and Technical Capabilities
CAPABILITY ASSESSMENT LEGEND
Status Current Mitigation Use Future Opportunity
Currently in use or present. Used widely for mitigation. Opportunity to expand and integrate. (Sort of) Seldomly used or limited
presence.
Limited use in mitigation planning. Limited opportunity to expand and integrate. (No) Not present or available. Not used in mitigation planning. No opportunity to expand or integrate.
HMP Integration
Resource Status
Current
Mitigation
Use
Future
Opportunity Notes / Additional Detail
Administrative and Technical
Community Planning and
Development Services
Community Planner
Green Green Yellow
City staff are well-staffed in general. There are
limited opportunities to better integrate
positions across the board with hazard
mitigation because of this strong staffing and
integration to date.
Civil Engineer Green Green Yellow Senior Civil Engineer Building Code Official
Green Green Yellow Planning and Code Enforcement Division Manager
Floodplain Administrator Green Green Yellow Development Engineering Division Fire Marshall Green Green Yellow
Dedicated Public Outreach Personnel Green Green Yellow
GIS Specialist and Capability Green Green Yellow
Emergency Manager Yellow Yellow Yellow Fire Chief
Grant Manager, Writer, or Specialist Yellow Yellow Green Part of job descriptions for other positions Warning Systems/Services
General
Green Green Yellow
City of Napa Facebook; City of Napa Twitter;
Napa Nixle System; local print and broadcast
media; homepage of the City of Napa website
Flood
Green Green Yellow
napa.onerain.com: a platform for Napa County
real-time rainfall and river-stream data
network
Wildfire Green Green Yellow Napa Nixle System
Geological Hazards Green Green Yellow Napa Nixle; ShakeAlert.org (nation-wide) 1-26-2022 Submittal EXHIBIT A Page 267 of 416
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5.3.5 Capability and Adaptive Capacity Opportunities
The City of Napa has adequate current capacity to continue implementing its HMP and strengthening regulatory and planning processes to ensure mitigation is integrated in city processes. The reflections in this section are meant as an example, not an exhaustive list of next steps to increase capacity. Prioritized opportunities to increase capacity in the city are shown as mitigation actions in Section 5.5.2.
The City has adequate plans in place to continue making progress on hazard mitigation. Most importantly, the City is currently updating its General Plan and will turn to updating its climate change planning materials thereafter. The City is also updating its Urban Water Management Plan. The region recently completed its first county-wide Community Wildfire Protection Plan and is developing the Napa Valley Drought Contingency Plan. Other planning documents may need updating soon, especially the City’s Storm Drainage Master Plan (2006), which could be updated to explore key drainage updates to address repetitive losses in the city.
City code also generally does a good job protecting future development from hazard impacts to the greatest degree practicable. In many instances, city code is stronger than the California codes and regulatory requirements, notably for water conservation and efficiency requirements and earthquake habitability protections. The City may consider strengthening WUI protections for new development in the firesusceptible hills on the edges of town.
The capability assessment identifies opportunities to explore new avenues of funding for hazard mitigation-related efforts. The City could also increase its education and outreach, an important step the public survey confirmed.
The following federal and state funding opportunities are provided as opportunities to leverage to increase capacity.
5.3.6 Federal and State Funding Opportunities
Table 5-5 is a list of available funding sources from state and federal agencies. This includes the FEMA Hazard Mitigation Assistance grant program, which is described in more detail in Section 6.3.5. This list serves as a resource and is not exclusive.
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Table 5-5: Federal and State Funding Opportunities
Agency /
Grant Name Potential Programs/Grants
FEMA Hazard Mitigation
Assistance Grants
See Section 6 for FEMA/ HMA grant details. For more information on current grants visit https://www.fema.gov/hazard-mitigation-assistance
▪ Hazard Mitigation Grant Program (HMGP): https://www.fema.gov/hazardmitigation-grant-program ▪ Building Resilient Infrastructure and Communities (BRIC):
https://www.fema.gov/grants/mitigation/building-resilient-infrastructurecommunities ▪ Flood Mitigation Assistance Grant Program (FMA):
https://www.fema.gov/flood-mitigation-assistance-grant-program FEMA other grant programs Including:
▪ Assistance to Firefighters Grant Program. Assistance to Firefighters Grants, Fire Prevention & Safety, and Staffing for Adequate Fire and Emergency Response. https://www.fema.gov/welcome-assistance-firefighters-grantprogram ▪ Emergency Management Performance Grants (EMPG). Good for Equipment, Back Up Generators, Etc. https://www.fema.gov/emergency-managementperformance-grant-program ▪ Regional Catastrophic Preparedness Grant Program (RCPGP). Housing and Logistics and Supply Chain Management, encouraging innovative regional solutions to issues related to catastrophic incidents, and building on existing regional efforts. https://www.fema.gov/regional-catastrophic-preparednessgrant-program U.S. Dept. of Energy / Energy
Efficiency and Conservation
Block Grant Program
Provides funding for weatherization of structures and development of building codes/ordinances to ensure energy efficiency and restoration of older homes. https://www.energy.gov/eere/wipo/energy-efficiency-and-conservation-block-grantprogram State and County
Community Development
Dept. Block Grants (CDBG)
Through Cal. Dept. of Housing and Community Development Dept. (HCD) Programs Include:
▪ Community Development (CD)
▪ Economic Development (ED)
▪ Disaster Recovery Initiative (DRI)
▪ Neighborhood Stabilization Program (NSP)
https://www.hcd.ca.gov/grants-funding/active-funding/cdbg.shtml Cal OES
Proposition 1B Grants
Programs
The Highway Safety, Traffic Reduction, Air Quality and Port Security Bond Act of 2006, approved by the voters as Proposition 1B at the November 7, 2006 general election, authorizes the issuance of $19,925,000,000 in general obligation bonds for specified purposes, including grants for transit system safety, security, and disaster response projects.
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Agency /
Grant Name Potential Programs/Grants
California Proposition 1: the
Water Bond (AB 1471)
Authorize $7.545 billion in general obligation bonds for state water supply infrastructure projects, such as public water system improvements, surface and groundwater storage, drinking water protection, water recycling and advanced water treatment technology, water supply management and conveyance, wastewater treatment, drought relief, emergency water supplies, and ecosystem and watershed protection and restoration.
The State Water Resources Control Board (State Water Board) will administer Proposition 1 funds for five programs. The estimated implementation schedule for each is outlined in Five Categories:
▪ Small Community Wastewater
▪ Water Recycling
▪ Drinking Water
▪ Stormwater
▪ Groundwater Sustainability
http://www.waterboards.ca.gov/water_issues/programs/grants_loans/proposition1.sht ml
Assistance to Firefighters
Grant Program (AFG); Fire
Prevention and Safety
(FP&S)
The primary goal of the FP&S Grants is to enhance the safety of the public and firefighters with respect to fire and fire-related hazards. The Grant Programs Directorate administers the FP&S Grants as part of the AFG Program. FP&S Grants are offered to support projects in two activity areas:
1). Fire Prevention and Safety (FP&S) Activity Activities designed to reach high-risk target groups and mitigate the incidence of death and injuries caused by fire and firerelated hazards. 2). Research and Development (R&D) Activity To learn more about how to prepare to apply for a project under this activity, please see the FP&S Research and Development Grant Application Get Ready Guide.
https://www.fema.gov/fire-prevention-safety-grants
California Housing and
Community Development
(HCD) Emergency Solutions
Grant (ESG) Program
To fund projects that serve homeless individuals and families with supportive services, emergency shelter/transitional housing, assisting persons at risk of becoming homeless with homelessness prevention assistance, and providing permanent housing to the homeless population. The Homeless Emergency Assistance and Rapid Transition to Housing (HEARTH) Act of 2009 places new emphasis on assisting people to quickly regain stability in permanent housing after experiencing a housing crisis and/or homelessness.
http://www.hcd.ca.gov/fa/esg/index.html
CalTrans Division of Local
Assistance / Safe Routes to
School Program
California Dept. of Transportation. Federal funding administered via Caltrans. Local 10% match is the minimum requirement.
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Agency /
Grant Name Potential Programs/Grants
Active transportation grant program. Creating mobility and connectivity. Prioritize projects, and preparation of PED for active transportation projects.
Property Assessed Clean
Energy (PACE) Programs
PACE financing allows property owners to fund energy efficiency, water efficiency and renewable energy projects with little or no up-front costs. With PACE, residential and commercial property owners living within a participating district can finance up to 100% of their project and pay it back over time as a voluntary property tax assessment through their existing property tax bill.
HazMat Emergency
Preparedness Grant
The purpose of this grant program is to increase effectiveness in safely and efficiently handling hazardous materials accidents and incidents; enhance implementation of the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA); and encourage a comprehensive approach to emergency training and planning by incorporating the unique challenges of responses to transportation situations. http://www.caloes.ca.gov/cal-oes-divisions/fire-rescue/hazardous-materials/hazmatemergency-preparedness-grant CERT Program Manager
Course
The purpose of this Community Emergency Response Team (CERT) Program Manager course is to prepare CERT Program Managers for the tasks required to establish and sustain an active local CERT program.
http://www.californiavolunteers.org/index.php/CERT/PM/
California Residential
Mitigation Program
The California Residential Mitigation Program (CRMP) was established to carry out mitigation programs to assist California homeowners who wish to seismically retrofit their houses.
http://www.californiaresidentialmitigationprogram.com/
Earthquake Brace + Bolt
(EBB)
EBB, part of the California Residential Mitigation Program, was developed to help homeowners lessen the potential for damage to their houses during an earthquake by offering eligible homeowners up to a $3,000 incentive to seismically retrofit their homes. https://www.earthquakebracebolt.com/
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Agency /
Grant Name Potential Programs/Grants
California Air Resources
Board Air Pollution
Incentives, Grants and
Credit Programs
These programs have hundreds of millions of dollars in grants available over the next several years to reduce emissions from on- and off-road vehicles and equipment. https://www.arb.ca.gov/ba/fininfo.htm
California Department of
Water Resources Grants and
Loans
https://water.ca.gov/Work-With-Us/Grants-And-Loans
Agency offers a variety of grants and loans related to integrated regional water management, flood mitigation, water conservation and efficiency, environmental restoration, groundwater, water quality, and water supply.
US Bureau of Reclamation
WaterSMART Grants
Annual funding available for:
▪ Water Reclamation and Reuse funding
▪ Drought Resiliency Project funding
▪ Water and Energy Efficiency Grant funding
https://www.usbr.gov/watersmart/
5.4 Mitigation Goals
Hazard mitigation plans must identify goals for reducing long-term vulnerabilities to identified hazards (44 C.F.R. § 201.6(c)(3)(i)). The Planning Committee established a set of goals for this plan based on data from the preliminary risk assessment and the results of the public involvement strategy. Goals discussed in this section describe what actions should occur. Specific, measurable mitigation actions explain how to accomplish the goals. The goals and actions form the basis for the development of the Mitigation Action Strategy and specific mitigation projects. The process consists of 1) setting goals, 2) considering mitigation alternatives, 3) identifying strategies or “actions”, and 4) developing a prioritized action plan resulting in a mitigation strategy.
The goals and mitigation actions in this plan all support each other. Actions were prioritized based on their ability to achieve multiple goals. A mitigation strategy is considered effective based on how well the goals of the strategy are achieved. The following are the goals for this plan:
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Goal 1: Promote a flood safe community. Flood safety is called out specifically as it is one of three hazards (along with earthquake and wildfire) ranked as potentially critical or catastrophic impact to the City. See Figure 4-1 (Hazard Risk Matrix).
Goal 2: Promote an earthquake safe community. Seismic safety is called out specifically as it is one of three hazards (along with flood and wildfire) ranked as potentially critical or catastrophic impact to the City. See Figure 4-1 (Hazard Risk Matrix).
Goal 3: Promote a fire safe community. Fire safety is called out specifically as it is one of three hazards (along with earthquake and flood) ranked as potentially critical or catastrophic impact to the City. See Figure 4-1 (Hazard Risk Matrix).
Goal 4: Promote an overall natural hazard-safe community. This goal includes all other hazards that may impact the City of Napa, including dam failure, extreme weather, drought, pandemic, and climate change. See Figure 4-1 (Hazard Risk Matrix).
Goal 5: Create a more disaster resilient community. This goal recognizes that disaster-resiliency may not relate to a specific hazard, and may instead be more holistic actions addressing community resiliency, emergency services, or community health.
5.5 Mitigation Actions
Mitigation actions were developed based upon planning committee priorities, risk assessment results, and mitigation alternatives. Most importantly, the newly-developed mitigation actions acknowledge updated risk assessment information outlined in Section 4.
Mitigation actions are available on MAST, linked through mitigatehazards.com, for city staff to update and track in real time, allowing for regular updating and easy sorting by priority and hazard type, for example.
Table 5-6 establishes updated mitigation actions for the city. The City developed mitigation actions specifically tailored to its vulnerabilities and capabilities. Those mitigation actions are available as part of the planning process library, which is summarized in Section 3, STEP 3 (City Planning Process Library) and are available on MAST.
Some mitigation actions support ongoing activities of the City, while other actions are intended to be completed when funding is available. All mitigation actions will be reviewed annually. 1-26-2022 Submittal EXHIBIT A Page 273 of 416
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5.5.1 Prioritization of Mitigation Actions
Implementing the identified mitigation can be overwhelming for any municipality, especially with limited staffing and fiscal resources; prioritizing the identified mitigation actions can help greatly with this. To ensure this HMP realistically reflects available resources, mitigation actions are prioritized by considering benefit cost review, public input, and HMP Planning Committee agreement.
5.5.1.1 Cost/ Benefit Review
The action plan must be prioritized according to a benefit/cost analysis of the proposed projects and their associated costs (44 C.F.R. §201.6(c)(3)(iii)). The benefits of proposed projects were weighed against estimated costs as part of the project prioritization process.
This review does not meet FEMA Hazard Mitigation Grant Program (HMGP) and Building Resilient Infrastructure and Communities (BRIC) grant program requirements. A less formal, less costly approach was used because some projects may not be implemented for up to 10 years, with costs and benefits could change dramatically in that time. Parameters were established for assigning subjective ratings (high, medium, and low) to the costs and benefits of these projects. Cost ratings were defined as follows:
▪ High—Existing funding will not cover the cost of the project; implementation would require new revenue through an alternative source (for example, bonds, grants, and fee increases). ▪ Medium—The project could be implemented with existing funding but would require a reapportionment of the budget or a budget amendment, or the cost of the project would have to be spread over multiple years.
▪ Low—The project could be funded under the existing budget. The project is part of or can be part of an ongoing existing program.
Benefit ratings were defined as follows:
▪ High—Project will provide an immediate reduction of risk exposure for life and property. ▪ Medium—Project will have a long-term impact on the reduction of risk exposure for life and property, or project will not provide an immediate reduction in the risk exposure for property. ▪ Low—Long-term benefits of the project are difficult to quantify in the short term.
Using this approach, projects with positive benefit versus cost ratios (such as high over high, high over medium, medium over low, etc.) are considered cost-beneficial and are prioritized accordingly. For many of the strategies identified in this action plan, the partners may seek financial assistance under the HMGP or BRIC programs, both of which require detailed benefit/cost analyses. These analyses will be performed on projects at the time of application using the FEMA benefit-cost model. For projects not seeking financial assistance from grant programs that require detailed analysis, the partners reserve the right to define “benefits” according to parameters that meet the goals and objectives of this HMP. 1-26-2022 Submittal EXHIBIT A Page 274 of 416
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5.5.1.2 Public Input
An 8-question community survey was distributed to the public, yielding 373 survey responses, including 15 in Spanish, and useful insight into the community’s perception of natural hazards affecting Napa.
Specific question responses heavily influenced the prioritization of mitigation actions, including the following summarized questions and responses:
▪ Property at risk? 81.8% of participants believe their property is at risk from a natural hazard disaster.
▪ Hazards experienced? Respondents primarily experienced the following hazards:
o Earthquake (73.8%) o Drought (49.7%)
o Summer severe weather: high heat
and high wind (57.8%)
o Wildfire (45.7%)
o Pandemic (55.7%) o Flooding (15%)
o Only 5% of respondents had not experienced a natural hazard. ▪ Consider risk of hazards with home purchase? 58.2% of participants considered the risk of naturally occurring hazards when choosing their home.
o Forty percent of Spanish-survey respondents considered the risk of naturally occurring hazards when choosing their home, and an equal percentage did not consider the risks. ▪ Informed about hazard risks? 62.5% of respondents felt they were well-informed about the dangers of natural hazards, while 30.8% felt somewhat informed and 6.7% felt uninformed. ▪ What incentives would encourage home protection from hazards? Top responses:
o Rebate programs or reimbursement of upfront costs (64.9%) o Insurance premium discounts (60.3%)
o Building permit fee waivers (46.4%)
o Home improvement cost-share grants (40.2%)
o Labor assistant for renters and homeowners (36.2%)
o Low-interest home improvement loans (31.9%)
▪ Top mitigation projects for local governments to focus on? Top responses:
o Work on improving damage resistance of utilities (73.7%) o Retrofit and strengthen essential facilities (56.3%)
o Ensure emergency shelters, the Emergency Operations Center, and communication towers have backup power generators (55.5%)
o Replant vegetation after wildfires to prevent landslides and flooding (55%) o Assist vulnerable property owners with securing funding to mitigate impacts to their property (53.1%)
o Replace inadequate or vulnerable bridges and roadways (51.7%) o Inform property owners of ways they can mitigation damage to property (49.3%) The complete survey results can be found in Appendix B. 1-26-2022 Submittal EXHIBIT A Page 275 of 416
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5.5.2 Mitigation Action Plan
Table 5-6 lists each mitigation action for the city.
These mitigation actions are also available on
MAST. Each mitigation action identifies the
responsible party, time frame, potential funding
source, implementation steps and resources needed
to implement these priority mitigation actions. As a
living document, hazard problem statements and
mitigation activities will be updated through MAST.
Figure 5-2 illustrates the Planning Committee
inputs that informed mitigation actions in MAST.
The detail provided in MAST and captured in Table
5-6 meets the regulatory requirements of FEMA and
DMA 2000.
The actions detailed in Table 5-6 and MAST contain
both new action items developed for this plan
Update as well as old actions that were yet to be
completed from the 2015 Plan. The action numbers
indicate whether the action is new or from the 2015
plan. An explanation of mitigation action
numbering is presented in Figure 5-1. Section 2,
What’s New, illustrates progress towards new and previous mitigation action and indicates how many actions have been completed, deleted, or are ongoing or pending Figure 5-1: Mitigation Action Key
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Figure 5-2: Diagram of MAST viewing details
Important note: The Planning Committee realizes that new needs and priorities may arise as a result of a disaster or other circumstances and reserves the right to support new actions and edit existing actions as necessary as long as they conform to the overall goals of the plan. 1-26-2022 Submittal EXHIBIT A Page 277 of 416
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INTENTIONAL BLANK PAGE
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Table 5-6: Mitigation Action Tracker
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-AH-CN-0 All Hazard ES -
Emergency
Services
Ongoing 2015 City of
Napa
Improve existing
communication systems,
especially developing
redundant communication
systems and wireless
infrastructure.
Fire Department, IT
Department, Napa
Police Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC ,
EMPG
Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
High ps-WF-CN13, ps-DFCN-41, psDF-CN-42
ma-AH-CN-1 All Hazard SP -
Structural
Projects
Pending 2015 City of
Napa
Build an alternate EOC Napa Fire
Department,
Utilities
Department, IT
Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project EMPG ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
High ps-AH-CN47
ma-AH-CN-2 All Hazard PRV -
Prevention
Ongoing 2015 City of
Napa
Create a Remote Workers
Infrastructure
IT Department High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
1-3 Years Project HMGP / BRIC Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
Medium ps-PN-CN46
ma-AH-CN-3 All Hazard PE&A -
Public
Education
&
Awareness
Ongoing 2015 City of
Napa
Promote greater public
awareness of disaster
preparedness, hazard
mitigation, and disaster
recovery.
City of Napa Fire
Department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing 5% Internal
Funding , N/A
Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
High ps-EQ-CN10, ps-CCCN-1, psCC-CN-2,
ps-CC-CN3, ps-DRCN-31, psFL-CN-26,
ps-FL-CN27
ma-AH-CN-4 All Hazard ES -
Emergency
Services
Ongoing 2015 City of
Napa
Maintain and equip an
Emergency Operation
Center(EOC) for immediate
availability in the event of a
disaster.
Fire Department, All
City Departments,
Utilities Department
and Finance
Department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing N/A N/A Goal 4: Promote an
overall natural hazardsafe community.
High ps-AH-CN47
ma-AH-CN-5 All Hazard PE&A -
Public
Education
&
Awareness
Ongoing 2015 City of
Napa
Work with local businesses to
prepare Emergency
Preparedness Plans by working
with other agencies and
advocacy organizations to
distribute to and assist
businesses with the preparation
of plans in the case of disaster.
Economic
Development
Department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
Ongoing N/A N/A Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
High ps-CC-CN1, ps-EQCN-8
1-26-2022 Submittal EXHIBIT A Page 279 of 416
HAZARD MITIGATION PLAN
CITY OF NAPA
CITY OF NAPA | HAZARD MITIGATION PLAN
5-26
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
the risk exposure for
property.
ma-AH-CN-7 All Hazard ES -
Emergency
Services
Pending 2015 City of
Napa
Develop short-term shelter
options for residents and
animals by working with the
American Red Cross, Humane
Society, animal shelters, pet
stores, local veterinarians and
others. Identify locations,
necessary facilities, responders,
etc.
Economic
Development Dept
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning EMPG ,
Internal
Funding
Goal 4: Promote an
overall natural hazardsafe community.
High ps-FL-CN27
ma-AH-CN-8 All Hazard PPRO -
Property
Protection
Ongoing 2015 City of
Napa
Develop procedures for
inspecting and tagging
business for occupancy after a
disaster (Post Disaster
Restoration Ordinance)
Building / Economic
Development Dept
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning EMPG ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community.
Medium ps-EQ-CN8, ps-DFCN-44
ma-AH-CN-9 All Hazard ES -
Emergency
Services
Pending 2015 City of
Napa
Establish the position of
Disaster Coordinator for the
City of Napa
Fire Department, All
City Departments,
Utilities
Department,
Finance Department
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
1-3 Years N/A N/A Goal 4: Promote an
overall natural hazardsafe community.
Medium ps-EQ-CN8, ps-DFCN-44, psWF-CN-12
ma-AH-CN-13 All Hazard ES -
Emergency
Services
Ongoing 2015 City of
Napa
Develop a program to identify
evacuation routes and
procedures for all sensitive
facilities and implement
programs to practice
evacuation and safety
maneuvers.
Napa Fire
Department,
Community
Development
Department,Utilities
Department, Police
Department
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing 5% EMPG ,
Internal
Funding
Goal 4: Promote an
overall natural hazardsafe community.
Low ps-AH-CN47, ps-FLCN-21, psFL-CN-20,
ps-EW-CN34
ma-AH-CN-57 All Hazard PRV -
Prevention
Ongoing 2021 City of
Napa
Construct backup generators at
critical facilities (fire stations,
hospital) and sheltering
locations to respond to hazard
events in loss of power.
Public Works Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing 5% HMGP / BRIC Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
High ps-EQ-CN9, ps-EQCN-10, psEW-CN-36,
ps-EW-CN37, ps-EWCN-38
1-26-2022 Submittal EXHIBIT A Page 280 of 416
CITY OF NAPA | HAZARD MITIGATION PLAN
HAZARD MITIGATION PLAN
CITY OF NAPA
5-27
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-CC-CN-14 Climate
Change
NRP -
Natural
Resource
Protection
Ongoing 2015 City of
Napa
Develop a Climate Action Plan
applicable with state and
federal law
Utilities
Department,
Building
Department, City
Manager
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning HMGP / BRIC Goal 5: Create a more
disaster resilient
community.
Low ps-CC-CN17
ma-CC-CN-51 Climate
Change
PE&A -
Public
Education
&
Awareness
Ongoing 2021 City of
Napa
Conduct public outreach
regarding cooling center
availability, especially targeting
vulnerable populations;
periodically review available
cooling center usage,
distribution and availability
throughout the City.
Public information,
fire department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing 5% HMGP / BRIC ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
Medium ps-CC-CN2, ps-CCCN-3, psCC-CN-4,
ps-CC-CN17, ps-EWCN-37, psEW-CN-38
ma-DF-CN-15 Dam
Failure
PRV -
Prevention
Ongoing 2015 City of
Napa
Maintain a program on dam
safety and continue to
cooperate with the State
Division of Dam Safety in
addressing any needed dam
maintenance or structural
improvements.
Utilities
Department,
Community
Development
Department, and
Napa Police
Department
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning NDSP Goal 1: Promote a flood
safe community.
High ps-DF-CN41, ps-DFCN-43
ma-DF-CN-52 Dam
Failure
ES -
Emergency
Services
Pending 2021 City of
Napa
Develop a dam failure
emergency operations plan
(EOP) at the City level or in
coordination with Napa County
Fire Department Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
1-3 Years N/A CDBG DRI ,
EMPG ,
Internal
Funding
Goal 1: Promote a flood
safe community.
High ps-DF-CN41, ps-DFCN-42, psDF-CN-43,
ps-DF-CN44
ma-DR-CN-16 Drought SP -
Structural
Projects
Ongoing 2015 City of
Napa
Secure internal and external
water supply sources and
maintain reservoir levels to
withstand drought years.
Utilities Department Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing Project HMGP / BRIC ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community.
High ps-CC-CN0, ps-DRCN-29, psDR-CN-32
1-26-2022 Submittal EXHIBIT A Page 281 of 416
HAZARD MITIGATION PLAN
CITY OF NAPA
CITY OF NAPA | HAZARD MITIGATION PLAN
5-28
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-DR-CN-54 Drought PRV -
Prevention
Ongoing 2021 City of
Napa
Develop a public education
campaign to encourage water
conservation during drought, in
collaboration with the Napa
Valley Drought Contingency
Plan Task Force and Napa
Sanitation District. The intent is
to avoid or delay issuance of
water restriction emergency
declarations.
Utilities, Public
Information
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years 5% HMGP / BRIC ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community.
Medium ps-DR-CN31, ps-DRCN-32, psDR-CN-33
ma-DR-CN-55 Drought PRV -
Prevention
Ongoing 2021 City of
Napa
Implement recommendations
from the Napa Valley Drought
Contingency Plan. Incorporate
into the City's Urban Water
Management Plan.
Utilities High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Planning HMGP / BRIC ,
Internal
Funding
Goal 5: Create a more
disaster resilient
community.
High ps-DR-CN30, ps-DRCN-32
ma-EQ-CN-17 Earthquake PE&A -
Public
Education
&
Awareness
Pending 2015 City of
Napa
Develop a program to educate
the community on the various
methods of retrofitting preearthquake code designed
structures, which would
include: workshops, literature
and public safety
announcements.
Community
Development
Department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Low - Long-term
benefits of the project
are difficult to quantify
in the short term.
1-3 Years 5% Internal
Funding
Goal 5: Create a more
disaster resilient
community. Goal 2:
Promote an earthquake
safe community.
High ps-EQ-CN7, ps-EQCN-10
ma-EQ-CN-18 Earthquake PPRO -
Property
Protection
Pending 2015 City of
Napa
Encourage the study and
rehabilitation of high
occupancy structures (such as
multi-family residences and
large public assembly facilities)
susceptible to collapse or failure
in an earthquake.
Community
Development
Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing Project HMGP / BRIC Goal 2: Promote an
earthquake safe
community.
High ps-EQ-CN5, ps-EQCN-5
ma-EQ-CN-20 Earthquake SP -
Structural
Projects
Ongoing 2015 City of
Napa
Install earthquake resistant
transmission and distribution
pipeline joints, automation
control features, and water
pipeline rehabilitation or
replacement across known
faults to protect against
catastrophic failures
Utilities Department High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC Goal 2: Promote an
earthquake safe
community.
Medium ps-EQ-CN6
1-26-2022 Submittal EXHIBIT A Page 282 of 416
CITY OF NAPA | HAZARD MITIGATION PLAN
HAZARD MITIGATION PLAN
CITY OF NAPA
5-29
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-EQ-CN-56 Earthquake PPRO -
Property
Protection
Pending 2021 City of
Napa
Encourage privately owned
unreinforced masonry
buildings and critical facilities
(e.g. churches, hotels, other
gathering facilities) to evaluate
the ability of the buildings to
withstand earthquakes and to
address any deficiencies
identified; explore a cost-share
program to assist private
owners in conducting seismic
retrofits.
Community
Development;
Building Dept
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC Goal 2: Promote an
earthquake safe
community.
High ps-EQ-CN8, ps-EQCN-7
ma-EW-CN-58 Extreme
Weather
PPRO -
Property
Protection
Pending 2021 City of
Napa
Develop cost share program to
help private landowners with
tree maintenance to avoid
power outages and damage
during windstorms.
City Admin/ Pub.
Works
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC Goal 5: Create a more
disaster resilient
community. Goal 4:
Promote an overall
natural hazard-safe
community.
Medium ps-EW-CN35
ma-EW-CN-59 Extreme
Weather
PPRO -
Property
Protection
Ongoing 2021 City of
Napa
Replace dying or dead
evergreen vegetation with wind
resistant vegetation and
implement annual tree
trimming program.
Public Works Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing N/A Internal
Funding
Goal 5: Create a more
disaster resilient
community. Goal 1:
Promote a flood safe
community.
Medium ps-EW-CN40
ma-FL-CN-23 Flood PRV -
Prevention
Ongoing 2015 City of
Napa
Complete approved Napa River
Flood Protection Project by
continuing to assist the U.S.
Army Corps of Engineers, Napa
County Flood Control and Water
Conservation District, other
responsible agencies, and the
public to maintain funding for
the development of the Flood
Project.
Community
Development
Department,
Utilities Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing Project HMGP / BRIC ,
FMA
Goal 1: Promote a flood
safe community.
Extreme ps-FL-CN20, ps-FLCN-21, psFL-CN-22,
ps-CC-CN19, ps-FLCN-28
ma-FL-CN-24 Flood SP -
Structural
Projects
Ongoing 2015 City of
Napa
Pursue funding for the design
and construction of storm
drainage projects to protect
properties that will not be fully
protected by the Flood
Protection Project, including
home elevations, property
acquisitions, upstream storage
such as detention basins, and
channel widening with the
associated right-of-way
acquisitions, relocations and
environmental mitigations.
Community
Development
Department,
Utilities Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing Project HMGP / BRIC ,
FMA
Goal 1: Promote a flood
safe community.
High ps-FL-CN20, ps-FLCN-21, psCC-CN-19,
ps-FL-CN28
1-26-2022 Submittal EXHIBIT A Page 283 of 416
HAZARD MITIGATION PLAN
CITY OF NAPA
CITY OF NAPA | HAZARD MITIGATION PLAN
5-30
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-FL-CN-25 Flood PE&A -
Public
Education
&
Awareness
Ongoing 2015 City of
Napa
Coordinate with County to
improve Countywide flood
surveillance/early warning
system
County Public
Works, City Utilities
Department
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing 5% Internal
Funding
Goal 1: Promote a flood
safe community.
High ps-FL-CN25
ma-FL-CN-26 Flood SP -
Structural
Projects
Pending 2015 City of
Napa
Complete Soscol Interior
Drainage Project Preliminary
Design
Napa Community
Redevelopment
Agency, City of
Napa Utilities
Department
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Completed Project N/A Goal 1: Promote a flood
safe community.
High ps-FL-CN28
ma-FL-CN-27 Flood PRV -
Prevention
Ongoing 2015 City of
Napa
Continue to apply floodplain
management regulations for
development in the flood plain
and floodway.
Community
Development
Department,
Utilities Department
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
Ongoing Planning HMGP / BRIC ,
FMA
Goal 1: Promote a flood
safe community.
High ps-CC-CN19
ma-FL-CN-28 Flood PRV -
Prevention
Ongoing 2015 City of
Napa
Increase coverage of Storm
Watch sensors to include small
streams that, due to land use
changes, have demonstrated an
impact on existing streams and
urban flooding.
County Public
Works, City Utilities
Department
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
1-3 Years Project HMGP / BRIC ,
FMA , Internal
Funding
Goal 1: Promote a flood
safe community.
Medium ps-CC-CN19
ma-FL-CN-29 Flood PE&A -
Public
Education
&
Awareness
Pending 2015 City of
Napa
Distribute NOAA weather
Radios to high risk, limited
income families living in flood
zones. Develop program of at
cost NOAA radios for families in
the various flood zones in Napa
County. Provide weather radios
to block captains.
County Disaster
Education Taskforce
Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
1-3 Years Project N/A Goal 5: Create a more
disaster resilient
community. Goal 1:
Promote a flood safe
community.
Low ps-FL-CN25, ps-CCCN-19
ma-FL-CN-30 Flood PRV -
Prevention
Ongoing 2015 City of
Napa
Periodically update the Flood
Insurance Rate Maps to reflect
the improvements that have
been completed as part of the
Flood Protection Project.
Community
Development
Department,
Utilities Department
& County of Napa
Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Low - Long-term
benefits of the project
are difficult to quantify
in the short term.
Ongoing Planning FMA Goal 1: Promote a flood
safe community.
High ps-FL-CN23
1-26-2022 Submittal EXHIBIT A Page 284 of 416
CITY OF NAPA | HAZARD MITIGATION PLAN
HAZARD MITIGATION PLAN
CITY OF NAPA
5-31
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-FL-CN-49 Flood PRV -
Prevention
Pending 2021 City of
Napa
Implement various flood
control projects after approved
Flood Control Project. For
example, additional pump
stations are needed to increase
the functionality and resilience
of the flood wall along the west
side of the Napa River.
In partnership,
Public Works
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
5-10 Years Project HMGP / BRIC ,
FMA , Internal
Funding
Goal 1: Promote a flood
safe community.
High ps-FL-CN24, ps-FLCN-20, psFL-CN-21,
ps-FL-CN22, ps-FLCN-28, psEW-CN-34,
ps-FL-CN28
ma-FL-CN-62 Flood/
Heavy Rain
SP -
Structural
Projects
Pending 2021 City of
Napa
Implement the Trower Avenue
Storm Drain Improvements,
Phase II project, which consists
of improvements to alleviate
flooding from heavy rain events
along Valencia Street, Yosemite
Street, Diablo Street and Glacier
Drive.
Public Works High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC ,
FMA
Goal 4: Promote an
overall natural hazardsafe community. Goal 1:
Promote a flood safe
community.
High ps-FL-CN22, ps-FLCN-25, psFL-CN-28
ma-PN-CN-31 Pandemic ES -
Emergency
Services
Ongoing 2015 City of
Napa
Coordinate efforts with health
community to respond to
communicable diseases
Fire Department Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning Internal
Funding
Goal 4: Promote an
overall natural hazardsafe community.
High ps-PN-CN46
ma-PN-CN-32 Pandemic PE&A -
Public
Education
&
Awareness
Ongoing 2015 City of
Napa
Ensure that the city, the
hospitals and the County
Health Dept. coordinate efforts
to educate, prepare for and
respond to outbreaks of
communicable disease
Fire Department Low - The project could be
funded under the existing
budget. The project is part of
or can be part of an ongoing
existing program.
Medium - Project will
have a long-term
impact on the
reduction of risk
exposure for life and
property, or project will
not provide an
immediate reduction in
the risk exposure for
property.
Ongoing Planning Internal
Funding
Goal 4: Promote an
overall natural hazardsafe community.
Medium ps-PN-CN46
ma-PN-CN-60 Pandemic PRV -
Prevention
Pending 2021 City of
Napa
Assess and institute necessary
upgrades to critical facilities to
allow for usage during
pandemic, including adequate
ventilation and physical
barriers
Public Works Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
3-5 Years Project HMGP / BRIC ,
CDBG DRI ,
EMPG ,
Internal
Funding
Goal 4: Promote an
overall natural hazardsafe community.
Medium ps-PN-CN45
1-26-2022 Submittal EXHIBIT A Page 285 of 416
HAZARD MITIGATION PLAN
CITY OF NAPA
CITY OF NAPA | HAZARD MITIGATION PLAN
5-32
Mitigation No.
Hazard
Type
Mitigation
Type Status Year
Primary
Agency Title/Description Responsible Party Estimated Cost Estimated Benefit Time
Frame
HMA
Activity
Type
Potential Grant
Source Goal Priority
Related
Problem
Statements
ma-WF-CN-41 Wildfire PPRO -
Property
Protection
Ongoing 2015 City of
Napa
Develop Structural Protection
Plans for Wildland Urban
Interface Areas
Fire Department Medium - The project could
be implemented with
existing funding but would
require a re-apportionment
of the budget or a budget
amendment, or the cost of
the project would have to be
spread over multiple years.
High - Project will
provide an immediate
reduction of risk
exposure for life and
property.
1-3 Years Planning HMGP / BRIC ,
AFG
Goal 3: Promote a fire
safe community.
High ps-WF-CN12, ps-CCCN-18
ma-WF-CN-42 Wildfire PE&A -
Public
Education
&
Awareness
Ongoing 2015 City of
Napa
Continue to support the Napa
Communities Firewise
Foundation in the development
of Fire Safe Councils and
implementation of the 2021
Community Wildfire Protection
Plan
Fire Department,
Community
Development
Department, Napa
Communities
Firewise
Foundation, City
Council, Property
Owners
High - Existing funding will
not cover the cost of the
project; implementation
would require new revenue
through an alternative
source (for example, bonds,
grants, and fee increases).