San Luis Obispo City Council
January 17, 2023

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intense severity of the urban heat island effect, resulting in potentially disproportionate impacts on this population during extreme heat events. The West of South Higuera neighborhood (Census Tract 115.01) also stands out as a particularly vulnerable to extreme heat, with the area also near urban heat island hotspots and includes a high percentage of elderly and disabled residents.

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Source: Data received and downloaded from City of San Luis Obispo and the Trust for Public Land.

Figure 10 Urban Heat Island Effect, Regionally-Defined Disadvantaged Communities, and Tree Cover in the City

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EXTREME HEAT POLICIES
Policy HE-4.1: Climate-Smart Urban Heat Mitigation
The City shall equitably mitigate the effects of extreme heat in outdoor environments.

Policy HE-4.2: Equitable Access to Safe Indoor Spaces
The City shall support equitable access to climate controlled indoor spaces.

Policy HE-4.3: Green and Healthy Buildings
The City shall support fuel switching retrofits (from fossil fuel to high-efficiency electric appliances), energy efficiency retrofits, and distributed energy resources as low carbon solutions to create safe, cool, and healthy buildings and consider programs and projects that support these retrofits as critical to maintaining community safety and to supporting disaster preparedness.

EXTREME HEAT PROGRAMS
Program HE-4.4: Urban Heat Island Mitigation Program
Develop and implement a program to mitigate the projected increasing impacts from the urban heat island effect. This program should include:
• A strategy to maintain and enhance the city’s urban tree canopy and other vegetative features to help reduce the urban heat island effect while accounting for the effect of shifting average minimum and maximum temperatures on sensitive tree species and vegetation.
• A “cool pavement” pilot to reduce the urban heat island effect being generated from the city’s pavement surfaces, focusing on large surface parking lots and urban heat island hotspots. Should the pilot prove effective, consider scaling the program, including through the adoption of new standards for new development projects, as appropriate, to use high-albedo or cool pavements for surface parking lots. • A Climate-Smart Green Infrastructure Strategy with regular updates to the City’s Capital Improvement Program and Foundational Action Natural Solutions 2.1 in the City’s Climate Action Plan which focuses on preparing the City’s first Community Forest Plan by 2022 and planting and maintaining 10,000 new trees by 2035. • A review of and update to Section 12.38.090 “Landscaping Standards” in the City’s Municipal Code and other design guidelines to incorporate strategies to increase shading of buildings and parking lots to mitigate the urban heat island effect while also ensuring that the updated landscaping standards are aligned with recommended fire wise plant species.
• A review of and update to City development standards, where appropriate, to include building and site design features that mitigate the urban heat island effect including reflective roofing, solar carports.

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Program HE-4.5: Climate-Smart Urban Tree Canopy
Conduct analysis and incorporate climate change considerations into the City’s Community Forest Plan and update the City’s Street Trees Master List to prepare for increases in minimum and maximum temperatures and extreme heat events and corresponding drought and fire risk, identifying which trees will be most vulnerable to climate impacts and which species will thrive during future increases in temperature. Ensure that the updated Street Trees Master List does not include high water use trees or highly combustible trees. Emphasize the planting and care of appropriate climate-ready trees in locations where they will have the greatest chances of success in environmental conditions that are predicted to become more challenging (i.e., “right tree, right place”). Communicate the results of the analysis to help community members prepare for impacts on trees on private property.

Give high priority to water conservation in all urban forest-related actions. This could include species selection, irrigation method and time-of-day recommendations, mulching, co-location with natural drainages and stormwater runoff, etc.

Lumber from removed trees should be used in ways that store carbon indefinitely instead of releasing it back into the atmosphere, and these uses should be publicized to build awareness and support for climate action.

Program HE-4.6: Community Cool Zones Network
Work with community organizations, faith-based organizations, businesses, local government entities in SLO County, and other institutions to develop a Community Cool Zone Network comprised of air-conditioned spaces conveniently located throughout the city that can be opened during heat wave events to help prevent heat-related illness for vulnerable populations (e.g., elderly, youth, homeless, residents without air conditioning). Support network participants to conduct energy efficiency and building decarbonization improvements consistent with the City’s Climate Action Plan. Prioritize opening cool zone locations in areas with identified heatvulnerable populations and disadvantaged communities and consider co-locating with Resilience Hubs. Assess feasibility and efficacy of providing transportation options to the cooling network location to elderly residents and transit-dependent populations.

Program HE-4.7: Green and Healthy Buildings Program
Expand the City’s Green and Healthy Buildings Program (the existing building retrofit program focused on electrification per the 2020 Climate Action Plan) to include climate resilience retrofit features to help residents prepare for the impacts of climate change (e.g., extreme heat, wildfires, and wildfire smoke). This work should include conducting a gap analysis to identify portions of the city’s housing stock that are not equipped with air-conditioning or other cooling systems to address the projected increases in temperature and extreme heat events. As part of the building retrofit program, include proactive efforts (i.e., incentives, matching funds) to retrofit or assist with retrofitting the identified housing stock with climate resiliency features including:
• Adequate climate control equipment (e.g., heat pump HVAC-systems) with air filtration systems.
• Weatherization and energy efficiency improvements.

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• Distributed energy resources (e.g., rooftop solar, battery storage, electric vehicle battery to building equipment, etc.) to support grid-independent operation and to offset utility energy costs.
• Home hardening improvements to protect against wildfire.

Program HE-4.8: Extreme Heat and Emergency Preparedness As part of the next update of the City’s Emergency Operations Plan, incorporate a protocol for emergency operations during extreme heat events in the city. Identify extreme heat thresholds which, if exceeded, would trigger the opening of cooling centers in the city as well as emergency response efforts from appropriate City departments (e.g., Police Department, Fire Department, Parks & Recreation). Coordinate emergency response efforts in Program HE-4.9 regarding heatrelated community outreach with this strategy.

Program HE-4.9: Equitable Community Outreach For Extreme Heat Use information from the Hazards and Vulnerabilities Report that identifies areas in the City with vulnerable populations (e.g., linguistically isolated households, elderly, youth, homeless, individuals with chronic health conditions) to conduct targeted outreach to these neighborhoods and areas in the City. Increase education and training opportunities for residents to prepare for extreme heat events, with a prioritization on participation from vulnerable populations and businesses and institutions that house and/or support vulnerable populations. Work with community organizations and the San Luis Obispo County Health Department to provide additional resources and training to staff working with elderly populations on how to prevent health-related heat impacts (Paterson et al. 2014). Work with community organizations and schools to help mitigate the impacts of extreme heat and heat wave events on youth. Educate and train staff working with youth populations on how to prevent health-related impacts from extreme heat. Continually assess the effectiveness of the City’s public information and education efforts during heat wave events.

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OVERVIEW
A wildfire is defined as an uncontrolled fire spreading through vegetative fuels that poses a threat to life and/or property (San Luis Obispo County 2019). Wildfires can be ignited by natural events, such as lightning strikes, or can be caused by damaged infrastructure (e.g., downed power lines) or human activities (e.g., campfires, arson). Wildfires can move quickly, casting embers into downwind areas and spreading to developed areas, putting human lives and properties at risk.

Three factors that contribute significantly to wildfire behavior are topography, fuel, and weather:

Topography—An area’s terrain and slope affect its susceptibility to wildfire spread. Both fire intensity and the rate of spread increase as slope increases because heat from a fire tends to rise through convection. For this reason, wildfires tend to spread more slowly downhill. The arrangement of vegetation on a hillside can also contribute to increased or decreased fire activity on slopes.

Fuel—The type, condition, and volume of fuel material are key factors that influence wildfire behavior. Fuel sources are diverse and can include dead vegetative matter, live trees, brush, and cured grasses. Buildings and other structures, such as homes, can also be sources of fuel.

Certain types of plants are more susceptible to burning or will burn with greater intensity, and dead, dry plant matter tends to burn more easily than living plant matter. Thus, fire risk is increased significantly during periods of prolonged drought. The density of vegetation increases the amount of combustible material available, also called the fuel load.

Weather—Factors such as temperature, humidity, wind, and the occurrence of lightning affect the potential for wildfire and its spread. High temperatures and low humidity can dry out wildfire fuels, creating a situation in which fuel will ignite more readily and burn more intensely. Thus, wildfire risk increases during periods of drought. Wind is one of the most significant weather factors in the spread of wildfires. Higher wind speeds lead to faster wildfire spread and, oftentimes, greater fire intensity.

Environmental and climatic conditions in and around the city influence the frequency and magnitude of wildfires. The city often experiences high-wind events, such as the Santa Lucia winds, which originate inland and flow westward during the late summer and early fall, counter

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to the prevailing westerly winds that occur throughout much of the year. Santa Lucia winds contain little humidity, and summers in the city are hot and dry, with precipitation primarily occurring in the winter months. Thus, the combination of the relatively hot, dry Santa Lucia winds occurring at a time when vegetation in the County and the city is particularly dry following the summer months can contribute to the ignition and spread of large wildfires. Periods of low relative humidity, when dead trees and vegetation cannot absorb moisture from the air, can also increase the risk of wildfires (City of San Luis Obispo 2011).

The risk of wildfires and subsequent impacts to property and life is greatest at the wildland-urban interface (WUI), which is where urban development borders wildland fuels. Wildfire risk is compounded in areas of the WUI that are also located in or near High or Very High Fire Hazard Severity Zones. As such, the City has adopted WUI emission resistant exterior construction method and materials for exposure from wildfire citywide. Figure 11 includes CAL FIRE designated Fire Hazard Severity Zones in and surrounding the city. Portions of southwestern and northeastern parts of the city are located in or near a Very High Fire Hazard Severity Zones, and many of these portions of the city overlap with the WUI. Locations identified by CAL FIRE as Hazard Severity Zones for the City and County are identified in Appendix G (Cal Fire San Luis Obispo County Fire Hazard Severity Zone Map). Beyond these areas of the city, the risk of urban fires decreases, with most of the areas surrounding the city located in a Moderate Fire Hazard Severity Zone.

In addition to portions of the City that overlap with the WUI there are City facilities outside of City limits that are located within State Responsible Area fire hazard zones. The Water Treatment Plant and Reservoir #2 are located in the State Responsibility Area moderate zone, and the road between the facilities cross through a High Fire Severity zone. Additionally, the Salinas Reservoir (Santa Margarita) is within Federal Responsible Area high and very high zones.

Figure 12 shows the locations of fires that have occurred within 10 miles of the city between 1900 and 2020; four fires have occurred within city boundaries. Between 1900 and 2018, 490 wildfires have been recorded in the County (San Luis Obispo County 2019a). Notable fires that have occurred in the County include the Weferling fire (1960), the Las Pilitas fire (1985), the Chispa fire (1989), the Highway 41 fire (1994), the Highway 58 fire (1996), the Logan fire (1997), and the Chimney fire (2016). In total, these fires burned approximately 400,000 acres, destroyed numerous structures, and cost millions of dollars to suppress (City of San Luis Obispo 2019).

The Las Pilitas fire burned 75,000 acres and burned within city limits, damaging a number of structures (City of San Luis Obispo 2011). The 1994 Highway 41 fire burned more than 50,000 acres close to the city’s northern boundary and destroyed 42 homes, 61 other structures, and 91 vehicles (San Luis Obispo County 2019).

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Figure 11 Wildfire Hazard Severity Zones in and Surrounding the City of San Luis Obispo with Critical Facilities

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Figure 12 Wildfire Perimeters for Wildfires within 10 Miles of the City of San Luis Obispo (1900–2020)

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Wildfire Management
The City’s Fire Department is the main agency responsible for wildfire response, management, and mitigation in the city, with many fires being addressed through mutual aid by both the City’s Fire Department and CAL FIRE. Several agencies, including the County, provide support to incorporated areas, including the City, during wildfire events. Supporting agencies, such as CAL FIRE, are also available to mobilize during fire response if needed. In addition to having the authority to declare local emergencies, the County can provide support for evacuations, shelter, and other forms of assistance for municipalities, including the City (San Luis Obispo County 2016). The City can also declare a disaster declaration through the City’s Disaster Council, absent the County. Because fire risk is highest for regions of the city within the WUI, the City has produced detailed maps of these regions, indicating evacuation routes and other critical information for responders. Locations identified by CAL FIRE as Hazard Severity Zones for the City and County are identified in Appendix G (Cal Fire San Luis Obispo County Fire Hazard Severity Zone Map). The City’s Community Wildfire Protection Plan serves as the primary document for assessing wildfire risk in different areas in the city and helping to implement a series of policies and strategies to reduce this risk, including:

Education – The goal of the education policies and strategies are to prepare response organizations, communities, the public, and policy makers regarding appropriate community actions and interactions to reduce the unwanted impacts of fires in the WUI.

Fuel – The goal of the fuel policies and strategies are to mitigate the unwanted impacts of wildfires on communities through proper vegetation management techniques that reduce hazardous fuels and the resulting wildfire intensity.

Planning – The goal of the planning policies and strategies are to mitigate the unwanted impacts of wildfires on communities through community planning (including new resilient community design, retrofitting existing communities, and efforts that support community recovery from the impact of fire), response planning, evacuation planning, and preparedness planning for responders, communities, individuals, animals, and livestock.

Response – The goal of the response policies and strategies are to mitigate the unwanted impacts of wildfires on life, property, and resources by having an efficient and effective response that includes properly trained personnel, appropriate equipment, and a community prepared to take appropriate action or evacuation.

Ignition Resistance - The goal of the ignition resistance policies and strategies are to eliminate or mitigate structural ignitions from radiant heat, flame contact, or embers from WUI fires.

Wildfire Smoke
While the city is at risk from the impacts of wildfires, the city and its residents are also susceptible to impacts of smoke from wildfires in the coastal mountain ranges of central California and the Los Padres National Forest to the east of the city. Wildfire smoke in the surrounding region and, due to wind patterns, wildfires along the central coast in general, can greatly reduce air quality in the city and cause public health impacts as well as impacts to tourism and normal community functions. Community public health factors that can increase the impacts of wildfire smoke include the prevalence of asthma in children and adults; chronic obstructive pulmonary disease; hypertension; diabetes; obesity; percent of population 65 years of age and older; and indicators of socioeconomic status, including poverty, income, and unemployment. Exposure to wildfire smoke, particularly exposure to vulnerable populations, can result in worsening of respiratory

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symptoms, increased rates of cardiorespiratory emergency visits, hospitalizations, and even death (Rappold et al. 2017). In the summer of 2020, wildfire smoke alerts were issued for San Luis Obispo County due to poor air quality caused by the Dolan Fire near Big Sur. Wildfire smoke can also have impacts on the labor market and the economy in general, with air quality affecting the ability of outdoor workers to perform their work and impact industries that operate in the open air (e.g., wineries, recreation activities, sporting events) (Borgschulte et al. 2019).

Climate Change and Wildfires
The effects of climate change, including increased temperatures, and changes to precipitation patterns, will exacerbate many of the factors that contribute to wildfire risk. Recent research has found that increases in global temperatures may be affecting wind patterns and increasing global wind speeds, however these changes would not be experienced uniformly across geographies in the future (Chen 2020). While the impact of climate change on wind speeds is still uncertain, it is important to recognize this potential effect and how it may also contribute to wildfire risk in the future.

Increased variability in precipitation may lead to wetter winters and increased vegetative growth in the spring, and longer and hotter summer periods will lead to the drying of vegetative growth and ultimately result in a greater amount of readily burned fuel for fires. This has already been seen across the state in recent years, with the area burned by wildfires increasing in parallel with rising air temperatures (OEHHA 2018). These factors, combined with the increasing frequency and severity of intense wind conditions, will cause fires to spread rapidly and irregularly, making it difficult to predict fires’ paths and effectively deploy fire suppression forces. Pacific Gas and Electric (PG&E) also has several electrical transmission lines running through the city, which carry significant potential fire risk (Figure 13).

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Figure 13 PG&E Transmission Lines in the City of San Luis Obispo Relative humidity is also an important fire-related weather factor; as humidity levels drop, the dry air causes vegetation moisture levels to decrease, which consequently increases the likelihood that plant material will ignite and burn. With an increase in hotter and drier landscapes, humidity levels may continue to drop and result in higher fuel loads, increasing the risk of wildfire (Schwartz et al. 2015).

Given the city’s urban setting, with minor portions of the city in the VHFHSZ, the analysis for future wildfire risk analyzes changes in wildfire risk at the County level to assess how larger regional risks and potential impacts may affect the city. Using a statistical model based on historical climate vegetation, population density, and large fire history, Cal-Adapt provides projections for future annual mean acres burned within the County when wildfires do occur. CalAdapt does not account for current or planned wildfire management projects. Table 5 and Figure 14 shows the projected change in average annual area burned within the County under low and high emissions scenarios for the central population growth scenario at midterm and late-century timescales. The total area burned annually by wildfire within the County is expected to rise 15 percent from the historic (1961–1990) annual average of 22,852 acres to 26,497 acres in the near-term and increase in the midterm to 26,509 acres burned annually. In the late-century, average annual area burned in the County is projected to increase to 26,509 acres and decrease slightly to 24,382 acres under the low and high emissions scenarios, respectively (CEC 2019b).

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This reduction in annual average acres burned in the late-century period is noted in the research conducted to develop the Cal-Adapt wildfire tool. As vegetation type and fuel amount, structure, and continuity change in the future due to altered disturbance regimes (e.g., changes in the frequency, seasonality, duration, extent and severity of wildfire and infestations by beetles and other pathogens) and climate, future wildfire activity and its response to climatic variability may reduce wildfire activity in some ecosystems (Westerling 2018).

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Sources: Data downloaded from City of San Luis Obispo in 2020 and County of San Luis Obispo in 2020 and downloaded from Cal-Adapt in 2021.

Figure 14 Projected change in average annual area burned within San Luis Obispo County through 2099

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Importantly, Figure 14 illustrates that anticipated changes in wildfire impacts are not homogenous across the County; for instance, the Santa Lucia Wilderness and the La Panza Mountain range located in the southern central portions of the County will experience the larger increases in average area burned over the 21st century under both emissions scenarios. While these areas are outside of the city boundaries and jurisdiction, due to the regional characteristics of wildfire impacts, wildfire events in these areas could affect the city through secondary impacts such as short-term and long-term wildfire evacuees, wildfire smoke, and impacts on the County’s regional transportation network.

Table 5 Changes in Annual Average Area Burned in San Luis Obispo County Average Annual Area
Burned
Historic Modeled1
Average Annual
Area Burned
(1961-1990)
Near-Term
(2021-
2050)
Midterm
(2035-
2064)
Late-Century (2070-2099)
Medium
Emissions High Emissions
Average Annual Area
Burned (acres) 22,852 26,497 26,509 26,509 24,382
Notes: RCP = Representative Concentration Pathway.
1 Observed historical average annual area burned data were not available from Cal-Adapt; the modeled historical average annual area burned data under the medium emissions scenario was available and used as proxy data.

Source: CEC 2019d, hectares converted to acres

FIRE POLICIES
Policy FI-5.1: Reduce Wildfire Risk
The City shall reduce the risk of wildfires in city open spaces and in the wildland urban interface through timely implementation of the City’s Community Wildfire Protection Plan and the Vegetation Management Plan.

Policy FI-5.2: City-Wide Fire-Smart Land-Use Planning
The City shall minimize fire risk in land-use planning decisions including updates to zoning, subdivision codes and design criteria to mitigate wildfire hazards and reduce risks to new development.

Promote the following risk reduction measures in future land use planning efforts in the city:
• New subdivisions shall be prohibited in areas of “Very High” wildland fire hazard severity zone as shown in Figure 11 unless part of conservation or open space acquisition program. Development of existing parcels shall require a development plan to manage fuels, maintain a buffer zone, and provide adequate fire protection to the approval of the Chief Building Official. The development plan must be consistent with Policies required by the City’s Conservation and Open Space Element.
• Use wildfire risk analysis resources such as the CAL FIRE’s Fire and Resource Assessment Program data in updates to future housing site constraints analyses. • Promote the use of clustered development patterns for subdivisions to require less fire suppression resources and that are easier to defend during wildfire events.

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Policy FI-5.3: City-Wide Fire-Smart New Development
The City shall only approve development when adequate fire suppression services and facilities are available or will be made available concurrent with development, considering the setting, type, intensity, and form of the proposed development. Ensure that new development projects include adequate measures to minimize fire hazards while remaining in compliance with housing laws regarding objective design standards and discretionary review.

Fire protection plans should address wildland fuel transition zones surrounding the development and include the following components:
• Provisions for the maintenance of vegetation within the subdivision to reduce wildfire risk • Requirements for hardening of structures to mitigate fire risk that meets or exceed the California Building Code
• Landscaping and defensible space design around a proposed structure that reduces wildfire risk.

Policy FI-5.4: Fire-Smart Buildings and High Or Very High Fire Hazard Severity Zones The City shall reduce wildfire risk associated with new development by requiring all new development located within any CAL FIRE designated High or Very High Fire Hazard Severity Zone to:
• Meet or exceed the State’s Fire Safe Regulations (title 14, CCR, division 1.5, chapter 7, subchapter 2, articles 1-5 commencing with section 1270) and Fire Hazard Reduction Around Buildings and Structures Regulations (title 14, CCR, division 1.5, chapter 7, subchapter 3, article 3 commencing with section 1299.01). • Include designs to minimize pockets or peninsulas or islands of flammable vegetation within a development.
• Include additional access roads, where feasible, to ensure adequate access for emergency equipment and civilian evacuation concurrently. More than one evacuation route is required for substantial development (as defined in policy OP-7.3 Emergency Access and Evacuation) in Very High Fire Hazard Severity Zones. All requirements and any deviations will be at the discretion of the Fire Code Official. • Meet or exceed the California Building Code for Materials and Construction Methods for Exterior Wildfire Exposure (Title 24, part 2, Chapter 7A). • For all remodeled or rebuilt structures, require projects to meet current ignition resistance construction codes included in the State’s Fire Safe Regulations.

Policy FI-5.5: Wildfires and Critical Facilities
The City shall locate, when feasible, new essential public facilities outside of high fire risk areas, including, but not limited to, hospitals and health care facilities, emergency shelters, emergency command centers, and emergency communications facilities, or identifying construction methods or other methods to minimize damage if these facilities are located in a State Responsibility Area or Very High Fire Hazard Severity Zone.

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Policy FI-5.6 Maintain Fire Flow
The City shall ensure adequate fire flow is maintained within the City limits through ongoing maintenance, capital improvement public infrastructure upgrades, and improvements required in association with development projects and in compliance with applicable California Fire Safe Regulations.

Policy FI-5.7 Fire Suppression Infrastructure Resiliency The City shall maintain fire flow during scheduled and unscheduled power outages and interruptions through incorporation of power source resiliency and redundancy within City public water supply, treatment, and distribution infrastructure.

Policy FI-5.8: Wildfire and Parking Management
The City shall restrict on-street parking in high wildfire risk areas in San Luis Obispo during increased fire risk days in accordance with the Fire Code to ensure full access for fire trucks and emergency vehicles and to increase roadway accessibility during evacuation events. The City Fire Department and other departments shall identify streets and neighborhoods that are at increased wildfire risk using the CAL FIRE Fire Hazard Severity Zones, Wildland Urban Interface Areas identified by the City, or another internal process. Conduct community outreach to neighborhoods affected by the policy and provide detailed information on how and when the parking restrictions will be implemented.

Policy FI-5.9: Concurrency of Fire Protection Services
The City shall ensure that adequate fire protection staffing, facilities, and equipment required, to serve developments operating before, or in conjunction with development.

Policy FI-5.10: Climate-Smart Fire Protection
The City shall incorporate the most current climate science regarding wildfires into all future reviews and updates to the City’s fire and wildfire related documents (e.g., community wildfire protection plan).

Policy FI-5.11: Proactive Communications on Fire Risks and Prevention The City shall proactively communicate with the public about fire risks and prevention, including information about:
• wildfire smoke health impacts and available mitigation strategies • The “Ready, Set, Go!” wildfire preparedness program including defensible space, home hardening, personal wildfire action planning, and evacuation actions. • Public safety power shutoffs associated with high fire danger.

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FIRE PROGRAMS
Program FI-5.12: Implement the Community Wildfire Protection Plan Continue to implement the City’s Community Wildfire Protection Plan (CWPP) to reduce wildfire risk in the City’s wildland-urban interface including implementation of the CWPP Tactical Policy Measures which focus on the four key policy areas of community education, fuels management, planning, and emergency response preparedness on an ongoing basis. Update the CWPP, every 5 years or sooner, to incorporate new best practices, funding opportunities, new legislation regarding wildfire protection, and other wildfire protection planning resources.

Program FI-5.13: Implement the Vegetation Management Plan Continue to implement the City’s Vegetation Management Plan, conducting fuel reduction projects at the 12 large open space lands included in the plan, using vegetation management techniques appropriate for each open space including manual vegetation removal; tree removal; mechanical treatment, prescribed burning, livestock grazing, and chemical treatment. Update the Vegetation Management Plan, as needed, to incorporate regulations regarding new best practices, and new funding opportunities for vegetation management projects.

Meet with the yak tityu tityu yak tiłhini (Northern Chumash Tribe San Luis Obispo County and Region (ytt Tribe)), Northern Chumash Tribal Council, and other tribal bodies on an annual basis, or as needed to incorporate Traditional Ecological Knowledge approaches to vegetation management in the City where appropriate.

Work with private property owners, San Luis Obispo County, and Caltrans to conduct roadside vegetation clearance along public and private roadways in Very High Fire Hazard Severity Zones in the city. Ensure that fuel reductions provide an appropriate fuel buffer for evacuees should these roadways become congested during an emergency incident.

Develop an Urban Creek Vegetation Management Plan as part of the Waterway Management Plan update. The plan shall set forth a holistic vision to address excessive and noxious vegetation and dead material in the creeks and waterways in San Luis Obispo and surrounding areas. Work with private property owners and San Luis Obispo County to review and conduct vegetation management to ensure dead trees and vegetation are reduced to prevent fire from spreading to adjacent lands.

Program FI-5.14: Wildfire Ignition Source Reduction Program The City will work to reduce wildfire ignition sources within the City’s open space and creek systems in accordance with fire code amendments that restricts public access to hazardous fire areas as designated by the Fire Chief.

Program FI-5.15: Wildland-Urban-Interface Defensible Space and Home Hardening Program
Implement a program to assist homeowners, landlords, and business owners in improving the defensible space for structures in or near the very high fire hazard severity zones. The program will serve to connect participants to contractors with experience in developing or improving home hardening improvements (e.g., fire-safe building materials, fire resistant home vent upgrades).

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The program will seek funding to supplement the costs associated with defensible space improvements, prioritizing low-income participants and elderly or disabled residents who would not be able to implement defensible space improvements on their own. The program would be developed and administered in close collaboration with the City’s Fire Department and CAL FIRE to ensure appropriate standards for defensible space are implemented as part of the program consistent with AB 3074 (“Fire Prevention: wildfire risk : defensible space: ember-resistant zones”).

Program FI-5.16: Resident Information and Training on Fire Hazards The City will inform homeowners and tenants about local fire hazards, appropriate responses to fire, and ways to prevent loss, including home improvements that can reduce the impact of fire.

The City will promote the efforts of the Fire Safe Council.

The City will continue hosting community preparedness sessions and workshops as effective preparation resources for residents to aid themselves when needs exceed the availability of professional emergency response workers.

The City will support education programs in the lower grades, using displays and demonstrations to inform young children about fire safety, and in secondary schools, demonstrating the dynamic aspects of fire, including major factors contributing to fire hazard and the relationship of fire to the natural ecology. Fire prevention and evacuation lessons will be included in each program.

Program FI-5.17: Wildfire Smoke Protection Outreach Strategy Work with the San Luis Obispo Air Pollution Control District to ensure residents are educated on how to protect themselves and their homes from wildfire smoke impacts. Prioritize outreach campaigns to populations who are vulnerable to poor air quality and those who work with the population (e.g., elderly care nurses and assistances, teachers), conducting educational events at convenient locations for these residents.

The outreach strategy should also focus on supporting employers to maintain compliance with California Code of Regulations, Title 8, Section 5141.1, which applies to most outdoor workplaces where the current Air Quality Index (current AQI) for airborne particulate matter is

2.5 micrometers or smaller is 151 or greater, and where employers should reasonably anticipate that employees could be exposed to wildfire smoke. Compliance requirements and training instructions are included in California Code of Regulations, Title 8, Section 5141.1.

Program FI-5.18: Support Community Resilience During Public Safety Power Shutoffs Proactively provide information for the installation of battery storage systems for existing residential and non-residential developments, prioritizing opportunities for essential services such as hospitals, grocery stores, pharmacies, and other essential service businesses.

Develop a streamlined permitting process, including appropriate CEQA exemptions, for the installation of small- and large-scale battery storage systems in existing residential and nonresidential development as well as providing applicants information on available financing options. Prioritize grant or other resource allocation to residents facing additional risks from Public Safety Power Shutoffs (PSPSs) including the elderly and disabled. Explore the viability of

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vehicle-to-building (V2B) technologies that can provide resilience by using the energy stored in PEV batters to power loads inside residential, commercial, or public buildings.

Program FI-5.19 Fire Protection Plans Related to New Development.

Develop standards for new development in the Very High Fire Hazard Severity Zones or Wildland-Urban Interface Zones requiring preparation of project-specific fire protection plans, in addition to complying with all applicable state and local building and fire code regulations. Fire protection plans may include a risk analysis, discussion of fire response capabilities, compliance with fire safety requirements (defensible space, fire protection infrastructure, building ignition resistance, etc.), appropriate mitigation measures and design considerations for any nonconforming fuel modification, maintenance, and education for residents.

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OVERVIEW
Geologic conditions encompass the form of the ground surface, the composition and character of soils, rocks, and water at the ground surface and below, and the long-term movement of the Earth’s crust and mantle. These conditions determine the stability of the ground at a site, and how that site will respond to changes caused by people and by the natural forces of earthquakes and weather.

The frequency and strength of
earthquakes depend on the number and
type of faults that pass through an area.

The city is in a geologically complex and
seismically active region. Seismic
conditions here have the potential to
result in significant harm to people and
property. Some fault locations and
characteristics have been identified,
however, recent earthquakes in California
have shown that not all active faults are
revealed by surface features. Safety
precautions should be based on known
factors, as well as an awareness of the
limitations to current knowledge. This
Element must consider two of the direct
effects of an earthquake: rupture of the
ground surface along a fault, and ground
shaking that results from fault movement.

Other hazards associated with earthquakes are settlement, liquefaction, landslide, collapse of pipes and structures, fires, and flooding from dam failure.

Numerous faults transect valleys and hillside areas in San Luis Obispo.

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Surface Rupture
Surface rupture refers to the top of the ground moving unevenly along a fault: one side moves horizontally, vertically, or both, with respect to the other side. It typically occurs within an area of linear traces along previous ruptures, which mark a fault zone, and often in concert with movement on adjacent or intersecting faults. Rupture of the ground surface along a fault trace typically occurs during earthquakes of about magnitude 5 or greater. Surface rupture endangers life and property when structures or lifeline facilities are located on, or cross over, a fault.

The Los Osos Fault, adjacent to the City of San Luis Obispo, is identified under the State of California Alquist-Priolo Fault Hazards Act (Figure15). This fault’s main strand lies near the intersection of Los Osos Valley Road and Foothill Boulevard. It has been classified as active within the last 11,000 years. Additional site-specific studies may find other segments of the fault, in which case it would be appropriate for the California Department of Mines and Geology to expand the zone. The Los Osos Fault presents a high to very high fault rupture hazard to development and facilities in the Los Osos Valley.

Other faults in the vicinity of San Luis Obispo are the West Huasna, Oceanic, and Edna faults.

These faults are considered potentially active and present a moderate fault rupture hazard to developments near them. Figure 15 shows the locations of faults in the immediate San Luis Obispo area.

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Figure 15 Regional Faults and Seismic Hazard Designation Area

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Ground Shaking
Ground shaking refers to the vibration that occurs in response to displacement along a fault.

Typically, ground shaking has a side-to-side component as well as a vertical component, with the actual movement depending on the type of fault, a site’s distance from the fault, and the rock and soil conditions at the site. Shaking endangers life and property by damaging or destroying structures and lifeline facilities, including water distribution systems that carry water to the city from Whale Rock, Nacimiento and Salinas reservoirs. City reservoirs are not located near one another which reduces the likelihood of damage and loss of all water supplies. Several faults can produce strong ground motion in San Luis Obispo. These are the Los Osos, Point San Luis, Black Mountain, Rinconada, Wilmar, Pecho, Hosgri, La Panza, and San Andreas faults (Figure 15). The San Andreas Fault and the offshore Hosgri Fault, which present the most likely source of ground shaking for San Luis Obispo, have a high probability of producing a major earthquake within an average lifespan. The highest risk from ground shaking is found on deep soils that were deposited by water, are geologically recent, and have many pore spaces among the soil grains. These are typically in valleys.

Engineering standards and building codes set minimum design and construction methods for structures to resist seismic shaking. Model standards and codes are typically updated every few years at the recommendation of professional advisors, in response to review of the performance of structures and lifelines that have been subject to recent earthquakes. Local governments then amend or replace their codes to reflect those required by State law or recommended.

Settlement and Liquefaction
In this context, settlement means the ground supporting part of a structure or facility lowers more than the rest or becomes softer, usually because ground shaking reduces the voids between soil particles (and often with groundwater rising in the process). The result can be more strain on the supporting features than they were built to withstand, leading to cracked walls or floors and broken water and sewer lines. Liquefaction is the sudden loss of the soil’s supporting strength due to groundwater filling and lubricating the spaces between soil particles as a result of ground shaking. Soils with high risk for liquefaction are typically sandy and in creek floodplains or close to lakes. In extreme cases of liquefaction, structures can tilt, break apart, or sink into the ground. The likelihood of liquefaction increases with the strength and duration of an earthquake.

The soils in the San Luis Obispo area that are most susceptible to ground shaking, and which contain shallow ground water, are the ones most likely to have a potential for settlement and for liquefaction (Figure 16). The actual risk of settlement or liquefaction needs to be identified by investigation of specific sites, including subsurface sampling, by qualified professionals.

Previous investigations have found that the risk of settlement for new construction can be reduced to an acceptable level through careful site preparation and proper foundation design, and that the actual risk of liquefaction is low. (An example is the City’s fire station at Madonna Road and Los Osos Valley Road.)
The building code requires site-specific investigations and design proposals by qualified professionals in areas that are susceptible to settlement and liquefaction.

Subsidence is the gradual settling or sinking of the earth’s surface due to subsurface material movement at depth and is frequently associated with groundwater level declines and groundwater pumping. The San Luis Obispo Valley Basin Groundwater Sustainability Plan (GSP) adopted by the San Luis Obispo Valley Groundwater Basin Groundwater Sustainability

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Agencies includes an evaluation and mapping of subsidence potential within the San Luis Obispo Valley Basin, and identifies a preliminary sustainable yield estimate of 5,800-acre feet per year (afy) for the Basin, including 2,500 afy for the San Luis Valley Sub Area (San Luis Obispo Valley Basin Groundwater Sustainability Plan, WSC, 2021).

As required by Sustainable Groundwater Management Act legislation and regulations, land subsidence is a specific sustainability indicator that is monitored in the Basin, pursuant to management criteria regulated by the Department of Water Resources.

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Figure 16 Liquefaction Risk Areas

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Figure 17 Landslide Susceptibility Classes

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Slope Instability and Landslides
Slope instability can occur as a gradual spreading of soil, a relatively sudden slippage, a rockfall, or in other forms. Causes include steep slopes, inherently weak soils, saturated soils, and earthquakes. Improper grading and manmade drainage can be contributing factors. Slope instability may result in gradual or sudden damage to buildings, roads, and utility lines. Sudden movement can be a threat to lives through immediate injury or suffocation, or loss of access.

In the late 1990s, rain-saturated soil moved above houses on the Santa Lucia foothills.

Much of the development in San Luis Obispo is in valleys, where there is low potential for slope instability. However, the city contains extensive hillsides. Several are underlain by the rocks of the Franciscan group, which is a source of significant slope instability. The actual risk of slope instability needs to be identified by investigation of specific sites, including subsurface sampling, by qualified professionals.

The building code requires site-specific investigations and design proposals by qualified professionals in areas that are susceptible to slope instability and landslides.

Damage-Prone Buildings
Any type of building can be damaged in an earthquake, but some types are much more able to withstand quakes. In the past, many buildings were constructed of clay blocks, bricks, stone, or concrete blocks, with few or no steel members to resist separation of the masonry units. The weight and lack of connectivity within these unreinforced masonry buildings make them a particular threat to safety in an earthquake. Because many unreinforced masonry buildings have historic and architectural value, and contain viable businesses, there is reluctance to remove or replace them quickly. State law has required the City to identify unreinforced masonry buildings and implement a locally devised program to reduce risks. The City has surveyed them and required owners to evaluate their deficiencies and reinforcing needs. The City requires upgrades as buildings are remodeled or uses change, and provides fee credits to help offset some of the cost. A City law required the owners to complete seismic upgrades or demolish the buildings by 2017.

Some non-masonry buildings are especially prone to earthquake damage because they lack connections to their foundations or resistance to side-to-side motion. Examples include woodframe buildings with apartments over garages that have one side occupied by a door opening, and hillside houses with little or no bracing for tall supports on the downhill side. The City participates in a rehabilitation loan program and a Voluntary Seismic Retrofit Program that includes standard retrofit plans for free that helps correct such problems, along with other measures such as bracing masonry chimneys and anchoring water heaters, mainly for older homes.

Expansive Soils
Expansive soils can change dramatically in volume depending on moisture content. When wet, these soils can expand; conversely, when dry, they can contract or shrink. Sources of moistures that can trigger this shrink-swell phenomenon include seasonal rainfall, landscape irrigation, utility leakage, and/or perched groundwater. Expansive soil can develop wide cracks in the dry season, and changes in soil volume have the potential to damage concrete slabs, foundations, and pavement. Special building/structure design or soil treatment are often needed in areas with expansive soils

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POLICIES
Policy GE-6.1: Avoiding Faults
The City shall prohibit development atop known faults. Applications for development approvals within 100 meters (330 feet) of any fault that is previously known or discovered during site evaluation shall be subject to review and recommendation by a State-registered engineering geologist.

Policy GE-6.2: Avoiding Slope Instability
Development shall not be located on or immediately below unstable slopes, or contribute to slope instability. Any development proposed in an area of moderate or high landslide potential shall be subject to review and recommendation by a State-registered engineering geologist.

Policy GE-6.3: Avoiding Liquefaction Hazards
Development shall not be located in areas of high liquefaction potential unless a site-specific investigation by a qualified professional determines that the proposed development will not be at risk of damage from liquefaction. The Chief Building Official may waive this requirement upon determining that previous studies in the immediate area provide sufficient information.

Policy GE-6.4 Structural Stability
Require new development to ensure structural stability while not creating or contributing to erosion, subsidence, or geologic instability or destruction of the site or surrounding area. Ensure that soils reports are prepared by a licensed civil engineer with expertise in soils and geology.

Prior to acceptance, require soils reports by a certified engineering geologist when developing in the following areas:
a. Expansive soils and potential for subsidence
b. All areas having cut or fill material on property
c. Where there are known or suspected geologic, soils or hydrologic problems in the immediate vicinity.

PROGRAMS
Program GE-6.5: Update The Hillside Planning Program
Update the City’s Hillside Planning Program to ensure orderly development along the City’s hillside areas prioritizing slope stability, safe access, circulation, and evacuation routes.

Program GE-6.6 Safeguard The Integrity Of Utility Conveyance Systems Incorporate climate models and hazard impact assessment in the design and planning of maintenance and upgrades of public utility conveyance systems.

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OVERVIEW
The City has a comprehensive set plans, policies, and procedures in place to prepare for and respond to a variety of emergency events. In coordination with San Luis Obispo County, the City provides emergency services to the community.

EMERGENCY OPERATIONS
City government consists of approximately 457 regular full-time employees and 8 regular parttime employees and 11 departments at the time of the Climate Adaptation and Safety Element update. Key departments involved in emergency operations activities include:
• The City of San Luis Obispo Police Department;
• The City of San Luis Obispo Fire Department;
• The City of San Luis Obispo Utilities Department;
• The City of San Luis Obispo Public Works Department;
• The City of San Luis Obispo Parks & Recreation Department; and • The City Manager’s Office.

The City has many staff with specific training on the use of specialized equipment or areas of expertise that are essential in implementing mitigation actions. Additionally, the City has several key planning documents related to emergency operations that help support emergency operations. These plans and a brief description of their content and purpose are included below.

Emergency Operations Plan– This Plan provides policy and guidance for the coordination of planning efforts involving the City and related organizations. The San Luis Obispo Fire Department is responsible for Disaster Leadership and Preparedness coordination and will regularly revise and exercise Hazard Specific Annexes and related support materials, as appropriate. The 2022 Emergency Operations Plan covers the following types of major events:
• Earthquake
• Hazardous Materials Release

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• Multiple Casualty Event
• Transportation
• Fire
• Civil Disturbance-Terrorism-Active Shooter
• Diablo Canyon Nuclear Power Plant
• Adverse Weather
• Utility Disruption
• Pandemic
The Emergency Operations Plan also provides resource materials for staff in the event of an Emergency Operations Center activation, such as position specific checklists, resource directory, and specific plans related to debris management, disaster recovery, and Continuation of Operations and Reconstitution of Government.

City of San Luis Obispo Hazard Mitigation Plan (Annex G in the San Luis Obispo County Multi-Jurisdictional Plan) – The 2020 San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan was adopted by the City in June 2020. It includes a profile of existing hazards in the city, assess the probability and severity of each hazard event, and includes a comprehensive set of mitigation actions and implementation strategies while taking into account agency capabilities to help the City reduce risk from the identified hazards. To remain eligible for many state and federal funding, grants and assistance programs, the City must update the Hazard Mitigation Plan, at a minimum, every 5 years, which is based on the date of FEMA plan approval.

The City also coordinates with many external agencies (e.g., local, state, federal, private sector, and non-profits) which have capabilities to support hazard mitigation activities. Many of these agencies participated in the hazard mitigation planning process, including the following:
• County of San Luis Obispo – Airports
• County of San Luis Obispo – Office of Emergency Services • County of San Luis Obispo – Public Health Department
• Cal Poly – City & Regional Planning Department
• Cal Poly – Administration and Finance
• French Hospital Medical Center
• American Red Cross
• Sierra Vista Regional Medical Center
• San Luis Coastal Unified School District
• California Highway Patrol
• PG&E
• San Luis Obispo County Fire Safe Council
In addition to the plan and policy resources available to the City to mitigate hazards, the City has developed or participated in several hazard mitigation programs including:
• Unreinforced Masonry Hazard Mitigation Program
• Disaster Preparedness Program
• Floodplain Management Educational Program
• San Luis Obispo Chamber of Commerce Business Continuity Planning • County Public Health Emergency Preparedness Advisory Committee • National Flood Insurance Program and FEMA Repetitive Loss Properties • Community Wildfire Protection Program
• Greenbelt Protection Program

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CRITICAL FACILITIES
Critical facilities and infrastructure provide essential services to the public, such as preserving the quality of life and providing essential public safety, emergency response, and disaster recovery functions. Different types of critical facilities include medical facilities, evacuation and community centers, potable water and wastewater facilities, fire stations, and local law enforcement stations.

The County’s HMP organizes critical facilities the following four categories:

Emergency Services – Facilities or centers aimed at providing for the health and welfare of the whole population (e.g., hospitals, police, fire stations, emergency operations centers, evacuation shelters, schools).

Lifeline Utility Systems – Facilities and structures such as potable water treatment plants, wastewater, oil, natural gas, electric power and communications systems.

Transportation Systems – These include railways, highways, waterways, airways, and city streets to enable effective movement of services, goods and people.

High Potential Loss Facilities – These include nuclear power plants, dams, and levees.

Transportation infrastructure is discussed in greater detail in Section 3.1, “Assets at Risk” of the Hazard Mitigation Plan. Table 6 includes the City’s critical facilities and infrastructure are that have been evaluated for their replacement value and are included in Appendix G of the Hazard Mitigation Plan.

Table 6 Critical Facilities and Infrastructure in the City of San Luis Obispo Category Facility/Infrastructure Asset
Community and Recreational Facilities
City Hall
Library
Ludwick Community Center
Meadow Park Recreational Center
Mitchell Park Senior Center
Sinsheimer Pool and Park
Medical Facilities
Sierra Vista Regional Medical Center
French Hospital Medical Center
Schools
California Polytechnic State University
Cuesta College
Laguna Middle School
San Luis Obispo High School
Infrastructure
Critical Bridges
Essential Bridges
Higuera Box Culvert
Evacuation Route Roads
Other Essential City-Owned Roads
Communication Towers
Other City-Owned Facilities City Corporation Yard

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Category Facility/Infrastructure Asset
Community Development and Public Works
Administration
Parking Garages
Parks and Recreation Building
Prado Day Center
Utilities Administration
Police and Fire Stations
Dispatch Center
Fire Station #1
Fire Station #2
Fire Station #3
Fire Station #4
Police Main Building, Garage, Annex
Potable Water and Wastewater
Facilities
Fire Station #4 Well
Pacific Beach Well
Reservoirs
Eight Sewer Lift Stations
Sewer System Infrastructure (pipes) – Approx. 140 miles Water Resource Recovery Facility
Seven Water Pump Stations
Water System Infrastructure (pipes) – Approx. 180 miles Eleven Treated Water Storage Tanks
Water Treatment Plant
Note: N/A = not available.

Source: Modified from Table G.9 in San Luis Obispo County 2019b.

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Figure 18 Map of Critical Facilities in San Luis Obispo

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ACCESS AND EVACUATION
Per California Senate Bill 99 (SB99) the City has completed analysis to identify residential developments in hazard areas, including wildfire (Cal Fire Very High Hazard Severity Zones), flood (FEMA 100 and 500-year flood zones) and geological (areas of high landslide potential), that do not have at least 2 emergency evacuation routes. The analysis produced figure 18 which will be utilized to inform access and evacuation planning efforts and emergency operations conducted by the City.

RADIATION HAZARDS
The Diablo Canyon Power Plant is the primary hazard for ionizing radiation in the San Luis Obispo area. Risks result from the potential for mistakes during day-to-day operations, accidents associated with refueling, and damage from earthquakes or other causes. There is added risk from on-site storage of spent fuel that remains radioactive for several generations. Long-term, off-site storage facilities for spent fuel are not available. Protective systems are installed, and emergency plans are in place in the event that any part of the reactor system fails. Diablo Canyon is scheduled to be decommissioned in 2025 with potential extended operations through 2030 per Senate Bill 846 (SB 846, Dodd). Decommissioning will take approximately ten years after units are shutdown. The plant operator and local agencies have jointly prepared plans for warning, sheltering, evacuation, and other responses to radiation emergencies. Updated information regarding the Emergency Response Plan is distributed to the public each year.

Relatively low-level radioactive materials and waste result from some medical facilities and other sources. The use, transportation, and disposal of these materials are governed by State and Federal regulations.

Radon is a naturally occurring gas produced by the breakdown of traces of uranium in certain soils and rocks. This gas can accumulate inside structures where building materials emit or trap radon, posing a significant health hazard. Soils and rocks in the San Luis Obispo area are not known to be sources of radon, so it is not considered a substantial local hazard.

HAZARDOUS MATERIALS
Hazardous materials include a wide range of solids, liquids, and gases that are flammable, explosive, corrosive, or toxic. Because large amounts of hazardous materials are shipped through the San Luis Obispo area daily, transportation accidents pose the most significant hazardous material risk to residents and the environment. Hazardous materials are transported along highways, the railroad, and pipelines, which pass through the city.

Public exposure to hazardous materials also can result from their use by industry, agriculture, and services. In 2022, there were about 195 businesses in the city using hazardous materials in sufficient quantities to require filing a report with the Fire Department, as required by the California Health and Safety Code. Household use of hazardous materials is also a threat to health and the environment if used or disposed of improperly.

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Figure 19 Limited Evacuation Route Areas (SB-99 Zones)

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AIRPORT HAZARDS
The San Luis Obispo County Airport provides commuter, charter, and private service to the area.

The primary hazard associated with the airport is the risk of aircraft crashing on approach and take-off. Aircraft flight operations are determined largely by the physical layout of the airport and rules of the Federal Aviation Administration. Activities on the airport property are managed by the County.

Existing land uses under the approach and take-off paths include agriculture and businesses close to the airport, and shopping centers, dwellings, and schools at greater distances. State law requires the independent, countywide Airport Land Use Commission to adopt an Airport Land Use Plan for each airport. This plan establishes zones based on flight patterns, with the aim of having future development be compatible with airport operations, considering safety and noise exposure. State and County policies encourage future development to be consistent with the Airport Land Use Plan.

On May 26, 2021, The County of San Luis Obispo Airport Land Use Commission (ALUC) adopted the Amended and Restated San Luis Obispo County Regional Airport (SBP) Land Use Plan (ALUP) including Safety Zones as depicted in Figure 19. In accordance with state law, unless an overrule action is taken, the City’s General Plan is required to be consistent with the ALUP. City actions to approve permits, entitlements, or other land uses and project development must be consistent with policies of the ALUP and/or specific plans which were found consistent with the ALUP at the time of the update.

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Figure 20 ALUP Safety Zones

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CITY OPERATIONS AND EMERGENCY SERVICES POLICIES
Policy OP-7.1: Emergency Preparedness and Response
Ensure the City and all relevant City departments have adequate planning, organization, and resources for emergency preparedness and emergency response.

The following response-time programs are intended to apply to recurrent types of emergencies, not rare, area wide disasters:

A. The Fire Department has set a response-time objective of four minutes. (The Fire Department’s Master Plan recommends that a three-person engine company, with paramedic, meet this standard 90 percent of the time).

B. The Police Department has set a one-third (33%) available-time objective for patrol response. (“Available time” is the fraction of total time that a patrol unit is not previously assigned or otherwise unavailable for response to a new emergency call for service.) The presence of available time during a shift allows Officers to perform proactive policing methods to deter and prevent crime, rather than responding to crime once reported.

Policy OP-7.2: Climate-Informed Emergency Operations Planning The City shall incorporate climate projections and climate impact data into the Emergency Operation Plan updates.

Policy OP-7.3: Emergency Access and Evacuation
Substantial development will be allowed only where multiple routes of road access can be provided, consistent with other General Plan policies on development location and open space protection and community risk reduction. “Substantial development” means industrial, commercial, and institutional uses, multifamily housing, and single-family dwellings in accordance with adopted fire code. “Multiple routes” include vehicle connections that provide emergency access only, as well as public and private streets.

Policy OP-7.4: Minimizing Hazardous Materials Exposure
The City shall minimize people’s exposure to hazardous substances through ensuring businesses that use, store, or transport hazardous materials to take adequate measures to protect public health and safety.

Policy OP-7.5: Mitigating Hazards from New Development
New development with sensitive land uses shall be buffered from stationary sources and mitigated from non-stationary sources of pollution. Development, including access and utility systems, shall be directed away from hazardous areas as described in the Hazard Mitigation Plan. Where development, including access and utility systems, cannot avoid hazardous areas, the development shall adequately mitigate the hazards and provide that the City and all relevant City departments have adequate planning, organization, and resources for emergency preparedness and emergency response. Hazard mitigation measures shall not significantly impact the environment, including wildlife habitats. Development shall pay an equitable share of

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the costs to mitigate area wide hazards. Hazard mitigation measures shall not burden taxpayers with high maintenance costs. Development shall not increase hazards for other properties in the area.

Policy OP-7.6: Hazardous Materials in City Operations
The City shall avoid using hazardous materials in its own operations to the greatest extent practical, and will follow all established health and safety practices when they are used. When managing pests and invasive plants, the City should use Integrated Pest Management practices and avoid the use of chemical insecticides and herbicides to the greatest extent practical.

Policy OP-7.7: Business and Economic Resilience
The City shall incorporate climate projections and climate impact data to develop business and economic resiliency.

Policy OP-7.8: Climate Change and Food Security
The City shall minimize potential impacts of climate hazards on food security.

CITY OPERATIONS AND EMERGENCY SERVICES PROGRAMS
Program OP-7.9: Climate Resilience Fund
Establish a Climate Resilience Fund to support the implementation of climate adaptation strategies identified in the Community Safety and Resilience Element by identifying and pursuing funding and financing opportunities for specific climate adaptation and climate-related hazard mitigation strategies. Identify high-priced climate adaptation strategies or capital improvement projects and research the feasibility of financing these efforts through green bonds or similar financing mechanisms.

Program OP-7.10: Emergency Operations Center
The City will maintain an Emergency Operations Center Plan, to prescribe the intended activation and operation of a single facility from which disaster response and essential city services will be supported. Fire Station 1 will serve as the Emergency Operations Center, with the Ludwick Center serving as the back-up emergency operations center. The Corporation Yard and the Police Station serving as department operating centers or tertiary back-up emergency operation centers if the primary and back-up locations are not viable. The primary Emergency Operations Center will transfer to the new Public Safety Center located at the existing Police Headquarters when construction is complete, and occupancy is permitted, at which time, the Fire Department will become the back-up EOC. The City will maintain back-up power sources for the primary and secondary EOC. If a permanent back-up power source is not feasible, the City will maintain portable back-up power sources.

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Program OP-7.11: Clean-Energy Microgrid for City Facilities Continue supporting the City’s current Carbon Neutral City Facilities plan. As part of this plan, if appropriate, conduct a feasibility study for developing a clean energy microgrid for key City facilities to provide clean, and reliant back-up power during utility disruptions (e.g., Public Safety Power Shutoffs or other disruptions) as well as providing local solar power to City facilities for non-emergency use during the day. Ensure that the feasibility study includes the following details to allow for the development of a City microgrid, if deemed feasible:
• A review of regulatory and operational considerations • A conceptual shovel-ready design of the technical components for a fully connected microgrid and an “islandable” solar + storage system
• A phasing strategy and procurement plan for implementation • An operational strategy that includes governance and cybersecurity • Key considerations for operation of the microgrid during short-term and long-utility disruptions
Seek funding sources including the California Energy Commission’s Electric Program Investment Charge (EPIC) Program and the Pacific Gas and Electric Community Microgrid Enablement Program (CMEP) to conduct a feasibility study.

Program OP-7.12: Critical Facilities Locations
The following City facilities are necessary for community function and emergency response:
• fire stations
• police main station
• water treatment plant
• raw water storage reservoirs/lakes
• wastewater treatment plant
• public works and utilities corporation yards
• principal telecommunications facilities
New City Critical facilities should not be located in 100-year floodplains, in areas of high or extreme wildland fire hazard, on sites subject to liquefaction or landslide (as distinguished from areas with potential for these hazards), atop earthquake faults or withing State-designated special studies zones, or where prohibited by the Amended and Restated San Luis Obispo County Regional Airport (SBP) Land Use Plan (ALUP). Where city operated critical facilities are located in these high hazard areas, they shall be flood protected and the city will identify, and when feasible, implement, mitigation strategies to limit the impacts of associated hazards.

The following facilities operated by entities other than the City, which are necessary for community function and emergency response, should not be located in 100-year floodplains, in areas of high or extreme wildland fire hazard, on sites subject to liquefaction or landslide [as distinguished from areas with potential for these hazards], atop earthquake faults or within Statedesignated special studies zones, or where prohibited by the Amended and Restated SBP ALUP:
• hospitals
• Caltrans and utilities corporation yards
• principal electrical substations
• principal natural gas transmission mains and pumping stations

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• principal public-utility telecommunications and emergency broadcast facilities • resilience hubs and community centers
Program OP-7.13: Water System Response Performance Standards The City will evaluate fire-flow capacities and identify deficiencies through testing and modeling of the public water system. For identified deficiencies, the Utilities and Fire Departments will propose remedies to meet recommended service levels based American Water Works Association (AWWA) standards and Fire Code regulations.

Program OP-7.14: Reducing Structural Hazards
The City will identify and evaluate hazards in existing structures and work toward reducing those hazards to acceptable levels of risk. The City will advocate that other organizations and agencies do the same. Highest priority will be given to critical facilities (listed in Program OP-7.12) and transportation facilities. This overall effort has five basic components:

A. The City’s continuing steps to evaluate, maintain, and replace its own facilities, in particular bridges, public assembly rooms, fire stations, water tanks, and water and wastewater treatment plants.

B. Routine inspections for code compliance in commercial, industrial, public-assembly, group-housing, and multifamily residential buildings.

C. Complaint-based inspections for code compliance in all buildings.

D. Implementation of the City-adopted program to identify and mitigate hazards of unreinforced masonry buildings.

E. Subject to adequate resources being provided through the budget process, outreach for private, woodframe buildings involving attachments to adequate foundations, cripple-wall bracing, water-heater attachment, and bracing or attachment of masonry chimneys.

Program OP-7.15: Coordinated Emergency Planning
The City will work within the Standardized Emergency Management System, an emergency response and coordination system used throughout California, the National Incident Management System, and the National Response Framework. The City will participate in periodic disaster-response drills, on a regional basis with all involved jurisdictions and involving the news media.

The City will review the SB99 Analysis, the hazard assessment studies and emergency response plans of utilities and of transportation agencies and companies operating in the San Luis Obispo area, and update the City’s Emergency Plan, including evacuation routes, as necessary.

Included in this program is the identification of existing public and private roadways in fire hazard severity zones and the wildland-urban interface (WUI) that are not in compliance with current fire safety regulations, including road standards for evacuation and emergency vehicle access, vegetation clearance, and other requirements of the California Fire Safe Regulations (California Code of Regulations - Title 14, Division 1.5, Chapter 7), to the extent resources are available.

Work at retrofitting City-owned roadways as needed to meet current standards and require private property owners to do the same, to the extent feasible and given the absence of other site constraints.

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The City will work with Caltrans to assure transport of hazardous materials follows Caltransapproved routes, with all necessary safety precautions taken to prevent hazardous materials spills. The City will train fire fighters, police officers, building inspectors, and public works.

Program OP-7.16: Climate Resiliency Checklist for New Development Similar to the City’s GHG Emissions Analysis Compliance Checklist, develop a Climate Resiliency Checklist to ensure that new residential and nonresidential development in the city is designed and built to withstand the forecasted impacts of climate change and incorporate Environmental Justice. Incorporate all appropriate policies related to new development that are included in the Community Safety and Resilience Element into the checklist. Items in the Climate Resiliency Checklist should be objective and comply with all relevant housing laws to eliminate discretionary review. Checklist items could include:

A. Energy design standards that incorporate future changes in annual average minimum and maximum temperatures
B. Additional battery storage requirements for certain types of development to mitigate impacts from future utility disruptions
C. Defensible space and home hardening requirements for development located in high wildfire risk areas designated by the City
D. Additional building design or site plan requirements to mitigate flood-related impacts in areas with current or future flood risk
E. Additional building design or landscaping requirement to reduce water consumption in new development
Program OP-7.17: Development Review and Inspections
The City will maintain and administer its Zoning and Subdivision Regulations and Community Design Guidelines in conformance with the General Plan. The standards and guidelines will be consistent with the requirements and recommendations of City police and fire departments.

A. City fire, police, public works, and utilities personnel will review applications for subdivisions and development projects, for consistency with safety objectives.

B. The City will maintain and administer its building and fire regulations in conformance with State requirements, including adoption of updated editions of uniform codes.

C. The City will conduct safety inspections for fire and hazardous materials in commercial, industrial, and multifamily residential buildings.

Program OP-7.18: Staff Training
The City will ensure standards, guidelines, and local ordinances are updated to ensure provision of adequate fire protection and emergency medical service for all persons and property in the community.

The City will train fire fighters, police officers, building inspectors, and public works and utilities staff to levels appropriate for their tasks and responsibilities. The City will provide training for those of its staff who apply its building regulations and planning standards, emphasizing the lessons learned in locations that have experienced disasters. The City will conduct disasterPage 315 of 1071 City Operations and Emergency Services
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response exercises for the types of non-nuclear disasters discussed in this element, coordinated with participation in required, periodic nuclear-disaster response training exercises. All public employees in the State of California are considered Disaster Service Workers (DSW) and as such the City will train all employees to ensure basic understanding of DSW responsibilities, the State Emergency Management System, National Incident Management System and the Incident Command System.

Program OP-7.19: Building City Capacity for Climate Resilience Identify key gaps in the City’s knowledge of climate adaptation planning and how to integrate the topic into work efforts. Establish a 1–3 year strategy and workplan to increase City staff capacity to fully integrate climate change adaptation as a key component of their work for appropriate departments and staff. Assess progress towards increasing staff capacity to address climate change on an annual basis and adjust strategy accordingly based on results and new information and guidance regarding climate adaptation planning. Establish the City’s Green Team as the official working group to help implement the suite of climate adaptation strategies included in the Climate Adaptation and Safety Element, identifying representatives from key City departments to lead climate adaptation efforts in those departments.

Program OP-7.20: Traditional Ecological Knowledge
Work with the yak tityu tityu yak tiłhini (Northern Chumash Tribe San Luis Obispo County and Region (ytt Tribe)), Northern Chumash Tribal Council, and other tribal bodies listed by the Native American Heritage Commission to incorporate Traditional Ecological Knowledge approaches into the City’s Conservation Guidelines for Open Space Lands.

Program OP-7.21: Climate-Smart Pest Management
Integrate Climate-Smart Pest Management Practices into the City’s Open Space Conservation Guidelines with consideration of how climate change is going to affect pest control and invasive species.

Program OP-7.22: Climate Informed Emergency Operation Plan During the City’s next comprehensive update of the Emergency Operations Plan (EOP), incorporate climate projections and climate impact data from the Climate Change Hazards and Vulnerabilities Report into the plan’s hazard identification and analysis to ensure hazard specific annexes address climate-related disasters. Analyze future staffing and resource requirements to adequately address the future frequency and intensity of climate-related hazards in the city.

Develop protocols for novel climate-related hazards that the city has previously experienced which are not adequately addressed in existing EOP hazard-specific annexes.

Program OP-7.23: Climate Informed Economic Development Strategic Plan Work with the local business community to identify key economic sectors that are vulnerable to impacts from climate-related hazards and other hazards identified in the Hazard Mitigation Plan (e.g., tourism) and develop a strategy to diversify the City’s economy to avoid overreliance on economic sectors that are vulnerable to climate impacts and local hazards. Work with the San Luis Obispo Chamber of Commerce to identify businesses and local industries already being affected by climate-related impacts (e.g., drought, wildfire smoke, extreme heat, flood) and identify opportunities to help support affected industries. Where economic vulnerabilities pose a

City Operations and Emergency Services
Climate Adaptation and Safety Element | 85
risk to ongoing City revenues, develop programs to bolster the City’s financial resilience through a Resilience Fund or other measures.

Program OP-7.24: Food Security
Work with community organizations (e.g., SLO Food Bank) and the SLO County Health Department to assess potential impacts of climate hazards on food availability, food prices and food insecurity in the city, particularly for disadvantaged communities. Partner with community organizations to address food insecurity including opportunities to support food recovery efforts as part of implementation of Senate Bill 1383 to reduce food waste and associated greenhouse gas emissions.

Implementation
Climate Adaptation and Safety Element | 86

OVERVIEW
This section provides information on how the City can successfully implement the set of policies and programs included in the Climate Adaptation and Safety Element. It describes how best to conduct ongoing community engagement during implementation as well as develop key regional and community partnerships to ensure successful implementation of the policies and programs.

The section also identifies appropriate funding and financing sources to support implementation.

Finally, the section provides a succinct timeline to help the City prioritize implementation of the policies and programs.

COMMUNITY ENGAGEMENT AND PARTNERSHIPS
Effective implementation of the policies and programs in the Climate Adaptation and Safety Element will require sustained collaboration with community partners and regional agencies, as well as collaboration among City departments. Collaboration with partners during the strategy implementation process ensures that knowledge and resources will be shared and allows the City to implement strategies effectively. Many of the strategies that focus on hazard preparedness involve helping residents prepare their household and neighborhoods for climate-related hazards (e.g., flooding, heat wave events). By conducting community outreach and involving residents in the implementation process, the City will ensure that the community overall will be better prepared to respond to and adapt to changing circumstances, whether they are chronic stresses, such as climate change, or acute shocks, such as an earthquake. Community engagement during implementation can also help create a committed group of community stakeholders who will help implement strategies and help create sustained commitment in the community for achieving successful implementation (Cal OES 2020). The City will utilize a whole Community approach which will attempt to engage the full capacity of the private and nonprofit sectors, including businesses, faith-based and disability organizations, and the general public, in conjunction with the participation of local, tribal, state, territorial, and Federal governmental partners. This Whole Community approach is a means by which residents, City officials, organizational and community leaders can collectively understand and assess the needs of their respective communities and determine the best ways to organize and strengthen their assets, capacities, and interests (FEMA 2011).

Climate Adaptation and Safety Element | 87

SUSTAINED COMMUNITY ENGAGEMENT
The City will need to host community outreach events to gather input on how best to implement the strategy and identify community priorities to help design strategy implementation. Many of the programs in the element will require sustained community participation or comprehensive infrastructure updates, requiring significant City staff time and resources. By conducting sustained community outreach during implementation, the City can gain support and buy-in from members of the community who will help advocate for and support implementation of these strategies.

The City is developing an interactive website that will provide a platform for easy access for residents and serve as a real-time tool to monitor and provide input on implementation of specific strategies. The website will also serve as a platform for community members to receive the most up-to-date information on ways to get involved in implementation of certain strategies, attend community events, and participate in other activities to support implementation. The website will be updated regularly to report progress on implementation of individual strategies.

IMPLEMENTATION WORKPLAN
The tables included in this section provides a ten-year timeline for when programs related to each hazard in the element should be implemented by the City. The implementation timelines have been designed to account for overlaps in similar programs to maximize the City’s capacity and resources for implementation as well as for the time required for the strategy to be fully implemented and become effective in mitigating various hazard.

Implementation
Climate Adaptation and Safety Element | 89

PROGRAM IMPLEMENTATION TIMELINE
Program Program Name Lead Department Immediate Near Term (2023-27)
Long term
(by 2035) Ongoing
High Impact Multi Hazard Resilience Solutions
MH-1.5 Update the City’s Capital Improvement Program to Incorporate Climate Projections
Public Works x
MH-1.6 Update City’s Engineering Standards and Specifications to Incorporate Climate Projections
CDD x
MH-1.7 Climate Smart Natural Resource Management Office of Sustainability and Natural
Resources
x
MH-1.8 Climate Resilience Hubs Office of Sustainability and Natural
Resources
x
MH-1.9 Post-Disaster Recovery Debris Management CSG x
MH-1.10 Post-Disaster Recovery Resources and Education CDD x MH-1.11 Regional Collaboration and Community Resilience Ambassadors Office of Sustainability and Natural
Resources
x
Environmental Justice
EJ-2.3 Empower Community Organizations Office of Sustainability and Natural
Resources
x
EJ-2.4 Ensure Public Engagement Noticing Manual Advances Procedural Equity Office of Diversity, Equity, and Inclusion
x
EJ-2.5 Develop Equity Checklist for City Programs and Capital Improvement Projects
Public Works x
EJ-2.6 Establish Community Resilience Fund Administration EJ-2.7 Report on Equity and Environmental Justice Progress Administration x Flooding
FL-3.7 Waterway Management Plan Office of Sustainability and Natural
Resources
x
FL-3.8 Flood Damage Prevention Office of Sustainability and Natural
Resources
x
FL-3.9 Sustainable Flood Management and Open Space CDD x FL-3.10 Urban Creeks Vegetation Management Plan Office of Sustainability and Natural
Resources
x
FL-3.11 Flood-Prepared Neighborhoods Program Fire Department x FL-3.12 Community-Driven Flood Education Administration x FL-3.13 Flood Warning Monitoring System CDD x
FL-3.14 Research and Develop Flood Protection Measures CDD x Extreme Heat
HE-4.4 Urban Heat Island Mitigation Program CDD x
HE-4.5 Climate-Smart Urban Tree Canopy Public Works x
HE-4.6 Community Cool Zones Network CDD x
HE-4.7 Green and Healthy Buildings Program Office of Sustainability and Natural
Resources
x

Climate Adaptation and Safety Element | 90
Program Program Name Lead Department Immediate Near Term (2023-27)
Long term
(by 2035) Ongoing
High Impact Multi Hazard Resilience Solutions
HE-4.8 Extreme Heat and Emergency Preparedness Fire Department x HE-4.9 Equitable Community Outreach for Extreme Heat CDD x Fire
FI-5.12 Implement the Community Wildfire Protection Plan Fire Department x FI-5.13 Implement the Vegetation Management Plan Office of Sustainability and Natural
Resources
x
FI-5.14 Wildfire Ignition Source Reduction Program Fire Department x FI-5.15 Wildland-Urban-Interface Defensible Space and Home Hardening Program Fire Department x FI-5.16 Resident Information and Training on Fire Hazards Fire Department x FI-5.17 Wildfire Smoke Protection Outreach Strategy Fire Department x FI-5.18 Support Community Resilience During Public Safety Power Shutoffs CDD x FI-5.19 Fire Protection Plans Related to New Development Fire Department x Earthquakes and other Geologic Hazards
GE-6.5 Update the Hillside Planning Program CDD x
GE-6.6 Inspect and Safeguard the Integrity of Utility Conveyance Systems Including Water Pipelines from City Reservoirs
Utilities x
City Operations and Emergency Services
OP-7.9 Climate Resilience Fund CDD x
OP-7.10 Emergency Operations Center Fire & Police
Departments
x
OP-7.11 Clean-Energy Microgrid for City Facilities Public Works x OP-7.12 Critical Facilities Locations CDD x
OP-7.13 Water System Response Performance Standards Utilities & Fire Departments
x
OP-7.14 Reducing Structural Hazards CDD x
OP-7.15 Coordinated Emergency Planning Fire & Police
Departments
x
OP-7.16 Climate Resiliency Checklist for New Development CDD x OP-7.17 Development Review and Inspections CDD x
OP-7.18 Staff Training Administration x
OP-7.19 Building City Capacity for Climate Resilience Administration x OP-7.20 Traditional Ecological Knowledge Office of Sustainability and Natural
Resources
x
OP-7.21 Climate-Smart Pest Management Office of Sustainability and Natural
Resources
x
OP-7.22 Climate-informed Emergency Operations Plan Fire & Police x

Climate Adaptation and Safety Element | 91
Program Program Name Lead Department Immediate Near Term (2023-27)
Long term
(by 2035) Ongoing
High Impact Multi Hazard Resilience Solutions
OP-7.23 Climate-informed Economic Development Strategic Plan Economic Dev. x OP-7.24 Food Security Administration & DEI x

Implementation
Climate Adaptation and Safety Element | 93

FUNDING AND FINANCING
Successful implementation of the resilience strategies will require both City staff time and resources. In many cases, it also will require funding for consultants to assist with implementation, as well as material costs to complete physical upgrades to the city’s infrastructure and the built environment. For other strategies, the City will be able to integrate strategies into existing operations and procedures, as well as into already planned projects. The funding required to implement the strategies will need to come from a variety of sources, including both external funding opportunities, such as grants, and the internal funding sources devoted to climate resilience, such as general fund revenue sources. The following discussion identifies available external funding opportunities and presents a summary of internal funding mechanisms that the City can use to implement the strategies.

EXTERNAL FUNDING OPPORTUNITIES
Federal, State, and local grants can help fill the gap for projects that cannot be funded from the City’s general fund or local funding mechanisms.

Federal Emergency Management Agency: Hazard Mitigation Assistance Grants FEMA’s hazard mitigation assistance grants provide funding for eligible mitigation measures that reduce disaster losses. FEMA administers four hazard mitigation assistance grant programs relevant to the City:

Hazard Mitigation Grant Program—Assists in implementing long-term hazard mitigation planning and projects following a Presidential major disaster declaration Flood Mitigation Assistance Program—Provides funds for planning and projects to reduce or eliminate the risk of flood damage to buildings that are insured annually under the National Flood Insurance Program
Building Resilient Infrastructure & Communities—Support for states, local communities, tribes, and territories as they undertake hazard mitigation projects, reducing the risks they face from disasters and natural hazards
Pre-Disaster Mitigation Program—Provides funds annually for hazard mitigation planning and projects
National Oceanic and Atmospheric Administration: Environmental Literacy Grants The goal of this funding opportunity is to improve the environmental literacy of K–12 students and the public so that they are knowledgeable of the ways in which their community can become more resilient to extreme weather and other environmental hazards and become involved in achieving that resilience. Projects are intended to build the collective environmental literacy necessary for communities to become more resilient to the extreme weather and other environmental hazards they face in the short and long term.

U.S. Department of Agriculture: Conservation Innovation Grants The Conservation Innovation Grant program is a voluntary program intended to stimulate the development and adoption of innovative conservation approaches and technologies while leveraging federal investment in environmental enhancement and protection, in conjunction with

Climate Adaptation and Safety Element | 94
agricultural production. These projects may be watershed-based, regional, or statewide in scope.

CivicSpark Program
The CivicSpark Program supports sustainability-focused research, planning, and implementation projects throughout California by providing public agencies and other organizations with capacity-building support to implement sustainability projects or programs from CivicSpark Fellows. Fellows serve for 11 months and can work on variety of issues including social equity, climate resilience, water resource management, affordable housing, and mobility.

California Climate Investments
California Climate Investments is a statewide initiative that directs funds from the State’s Capand-Trade Program to projects and programs that work to reduce greenhouse gas emissions in the state. These funds can support a variety of projects, including affordable housing, renewable energy, public transportation, environmental restoration, more sustainable agriculture, and recycling. Numerous State programs, including some discussed above, are funded through California Climate Investments; however, the State’s Cap-and-Trade Program continues to evolve and is updated by the State periodically to include new or modified programs.

LOCAL FUNDING AND FINANCING MECHANISMS
Considering that major updates to the City’s built environment (e.g., flood management system) may be needed to help prepare for current or future climate-relate hazards, financing mechanisms may need to be leveraged to pay for projects with large upfront costs. Financing requires a source of repayment, commonly referred to as funding, to secure a large upfront payment that is then paid back over time with interest.

In California, laws and regulations that govern how revenue can be raised from taxes, assessments, and fees, combined with the need for a variety of public investments competing for the same dollars, can make securing funding a larger challenge than securing financing.

Making a compelling case that ensures broad-based public support by clearly articulating the cost of inaction (e.g., what will be lost without the investment in the context of progressive climate impacts) and the resulting co-benefits is an important component of securing funding for climaterelated investments through mechanisms such as taxes, assessments, and fees, as well as successfully pursuing grants and other external funding opportunities.

After funding is secured, typical financing mechanisms used by local governments include municipal bonds and loans, although in recent years, additional types of bonds that include consideration of characteristics that may be relevant for climate-related investments, such as green bonds, are now offered. Selection of a financing mechanism should be based on the total cost of the financing and its suitability for funding the needed investment.

The mechanisms discussed below are a few of those commonly used to implement climate adaptation projects, which may have multiple sources of funding and/or financing. An assessment of which mechanisms would be used to pay for resilience strategies would be conducted as the City begins to implement the policies and programs.

Climate Adaptation and Safety Element | 95
Funding
Taxes: The cost of large infrastructure projects can be offset through various tax mechanisms.

For adaptation and resilience projects, a tax is generally a special tax that is implemented to pay for a specific project or program. Because of voter approval requirements, special taxes can be more difficult to develop without a clear understanding by the public of their purpose and the specific benefits they provide. Under California law, if a jurisdiction would like to adopt, increase, or extend a special tax, a two-thirds-majority approval is required. General taxes can pass with a simple majority. The following common types of taxes could be used to fund appropriate resilience strategies:
• Ad valorem property tax—This is a tax levied on property owners based on a property’s value.

It can be used only to finance voter-approved debt or finance bonds for infrastructure projects. The requirements for voter approval to raise property taxes depend on the type of infrastructure project being funded. In general, property tax increases for infrastructure bonds need approval by two-thirds of local voters.
• Parcel taxes—This is a form of property tax assessed based on certain established characteristics of a parcel rather than a rate based on the assessed value of the property. A parcel tax is considered a special tax and requires approval from two-thirds of all local voters. • Mello-Roos taxes—A Mello-Roos district is a special district established by a local government to obtain additional public funding for specific projects or services, such as emergency services (e.g., fire departments, police) or public work projects (e.g., infrastructure improvements).

Financing
Bonds: A bond is a financing tool whereby money borrowed from investors is paid back with interest. Bonds are bought and sold on the bond market. Local governments can finance specific resilience projects by issuing bonds.

Green Bonds: For adaptation and resilience projects, green bonds can expand the potential investor pool by characterizing aspects of the investment that interest investors focusing on projects with defined environmental performance characteristics, but this approach could have higher administrative costs. Several green and climate bond certifications, such as the Climate Bond Standard and the Green Bond Principles, have been created to standardize the definition of the environmental characteristics of green bond projects.

Loans
Loans are a financing tool whereby a party borrows money from a single source, such as a bank or the government, for a specific purpose. Loans can have fixed interest rates, as bonds do, but they often have variable interest rates, making them less attractive to cities that have budgets that fluctuate over time. Loan payback terms also tend to be shorter than bond payback terms.

Commercial loans are available to local governments for resilience- and infrastructure-related projects in California from the Infrastructure State Revolving Fund, which provides financing to nonprofits and public agencies for infrastructure and economic development (excluding housing).

Climate Adaptation and Safety Element | 96
°C degrees Celsius
°F degrees Fahrenheit
AB Assembly Bill
AR atmospheric river
CAL FIRE California Department of Forestry and Fire Protection Cal Poly California Polytechnic State University at San Luis Obispo CIP Capital Improvement Projects
City City of San Luis Obispo
County San Luis Obispo County
CWPP Community Wildfire Protection Plan
EOP Emergency Operations Plan
EMF electromagnetic field
FEMA Federal Emergency Management Agency
GHG greenhouse gas
HMP Hazard Mitigation Plan
LHMP Local Hazard Mitigation Plan
PG&E Pacific Gas and Electric
SB Senate Bill
SLOCOG San Luis Obispo Council of Governments
TAZ traffic analysis zone
U.S. 101 U.S. Highway 101
UHI urban heat island
VHFHSZ Very High Fire Hazard Severity Zones
WMP Waterway Management Plan

Climate Adaptation and Safety Element | 97
100-Year Flood: A flood that has a 1 percent likelihood of occurring in any given year. 100-Year Floodplain: The areas that have a 1-in-100 chance of flooding in any given year using criteria consistent with, or development by, the Federal Emergency Management Agency. 200-Year Floodplain: The areas that have a 1-in-200 chance of flooding in any given year using criteria consistent with, or development by, the Department of Water Resources. 500-Year Floodplain: The areas that have a 1-in-100 chance of flooding in any given year using criteria consistent with, or development by, the Department of Water Resources.

Adaptive Capacity: The ability of systems, institutions, humans, and other organisms to adjust to potential damage, to take advantage of opportunities, or to respond to consequences (IPCC 2014).

Alquist-Priolo Earthquake Fault Zone: A regulatory zone, delineated by the State Geologist, within which site-specific geologic studies are required to identify and avoid fault rupture hazards prior to subdivision of land and/or construction of most structures for human occupancy.

Climate Adaptation: Adjustment or preparation of natural or human systems to a new or changing environment that moderates harm or exploits beneficial opportunities.

Climate Mitigation (Greenhouse Gas Emissions Reductions): A human intervention to reduce the human impact on the climate system; it includes strategies to reduce greenhouse gas sources and emissions and enhancing greenhouse gas sinks. Refer to Chapter 7, Climate Change, for more information.

Critical Facility: Facilities that either (1) provide emergency services or (2) house or serve many people who would be injured or killed in case of disaster damage to the facility. Examples include hospitals, fire stations, police and emergency services facilities, utility facilities, and communications facilities.

Extreme Weather Event: In most cases, extreme weather events are defined as lying in the outermost (“most unusual”) ten percent of a place’s history. Analyses are available at the national and regional levels.

Fault: A fracture or zone of closely associated fractures along which rocks on one side have been displaced with respect to those on the other side. A fault zone is a zone of related faults which commonly are braided, but which may be branching. A fault trace is the line formed by the intersection of a fault and the earth’s surface.

Active Fault: A fault that has exhibited surface displacement within Holocene time (approximately the past 11,000 years).

Potentially Active Fault: A fault that shows evidence of surface displacement during Quaternary time (the last 2 million years).

Flooding: A rise in the level of a water body or the rapid accumulation of runoff, including related mudslides and land subsidence, that results in the temporary inundation of land that is usually

Climate Adaptation and Safety Element | 98
dry. Riverine flooding, coastal flooding, mud flows, lake flooding, alluvial fan flooding, flash flooding, levee failures, tsunamis, and fluvial stream flooding are among the many forms that flooding takes.

Greenhouse Gases (GHG): gases that trap heat in the atmosphere.

Hardening Structures: An action to reduce the vulnerability of homes and structures to embers and heat that accompany most wildfires, including use of proper construction techniques and choice of building materials.

Hazardous Material: An injurious substance, including pesticides, herbicides, toxic metals and chemicals, liquefied natural gas, explosives, volatile chemicals, and nuclear fuels.

Hazard Mitigation: Sustained action taken to reduce or eliminate long-term risk to people and their property from hazards and their effects.

Landslide: A general term for a falling, sliding, or flowing mass of soil, rocks, water, and debris.

Includes mudslides, debris flows, and debris torrents.

Liquefaction: A process by which water-saturated granular soils transform from a solid to a liquid state during strong ground shaking.

Representative Concentration Pathway (RCP): A term that represents plausible future greenhouse gas emissions trajectory through time. An RCP 8.5 is a no-mitigation scenario where global GHG emissions continue to rise throughout the 21st century that, for California, represents annual average temperatures increasing 4 -7 degrees Celsius by the end of the century.

Resilience: The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organization, and the capacity to adapt to stress and change.

Seiche: An earthquake-induced wave in a lake, reservoir, or harbor.

Subsidence: The gradual, local settling or sinking of the earth’s surface with little or no horizontal motion (subsidence is usually the result of gas, oil, or water extraction, hydrocompaction, or peat oxidation, and not the result of a landslide or slope failure).

Social cohesion: The extent of connectedness and solidarity among groups in society or community. Social cohesion is one of the strongest indicators of resilience during disaster events as well as in post-disaster recovery efforts (Townshend et al. 2015). Social cohesion can play an important role in helping protect residents, particularly vulnerable populations, during climaterelated disasters. While measuring the degree of social cohesion present in the City is not possible at this point, this subject is discussed here to emphasize the importance of social cohesion in increasing community resilience to the impacts of the climate change.

Tsunami: A wave, commonly called a tidal wave, caused by an underwater seismic disturbance, such as sudden faulting, landslide, or volcanic activity. Wildland Fire: A fire occurring in a suburban or rural area that contains uncultivated lands, timber, range, watershed, brush, or grasslands. This includes areas where there is a mingling of developed and undeveloped lands.

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American Planning Association. 2017 (May). APA Blog: Planning for Resilience. Available:
https://www.planning.org/blog/blogpost/9124762/. Accessed August 24, 2020.

APA. See American Planning Association.

Borgschulte, M, Molitor, D, and Zou, E, Y. 2019. Air Pollution and the Labor Market: Evidence from Wildfire Smoke. Institute of Labor Economics 2019 Annual Conference.

California Department of Forestry and Fire Protection. 2020. Fire and Resource Assessment Program Fire Perimeter Data. Available: http://frap.fire.ca.gov/data/frapgisdata-subset.

Accessed August 24, 2020.

California Energy Commission. 2019a. Cal-Adapt Annual Averages Tool. ———. 2019a. Cal-Adapt Annual Averages Tool.
———. 2019B. Wildfire Tool.

California Environmental Justice Alliance. 2017. SB 1000 Implementation Toolkit: Planning for Healthy Communities
California Natural Resources Agency. 2018 (January). Safeguarding California Plan: California’s Climate Adaptation Strategy. 2018 Update.

California Governor’s Office of Planning and Research, 2017, General Plan Guidelines.

California Governor’s Office of Planning and Research, 2020, General Plan Guidelines Chapter 4: Environmental Justice Element.

OEHHA 2018
Cal OES 2020
Cal Poly 2020
cbec eco engineering 2021
CEC 2019d
Chen, L. 2020. Impacts of climate change on wind resources over North America based on NACORDEX. Renewable Energy, 153, 1428-1438.

References
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Centers for Disease Control and Prevention. 2019. Protecting Vulnerable Groups from Extreme Heat [website].

City of San Luis Obispo. 2011. City of San Luis Obispo Emergency Operations Plan. ———. 2014 (December 9). Chapter 5, Safety. In City of San Luis Obispo General Plan. Adopted July 5, 2000. Last revised December 9, 2014. Available:
https://www.slocity.org/home/showdocument?id=6645. Accessed August 24, 2020.

City of San Luis Obispo 2019
City of San Luis Obispo 2021
CDC n.d.

EPA. See U.S. Environmental Protection Agency.

FEMA 1978
FEMA 2011 referenced from FEMA's "A Whole Community Approach to Emergency Management: Principles, Themes, and Pathways for Action" https://www.fema.gov/sites/default/files/2020-07/whole_community_dec2011__2.pdf George S. Nolte & Associates. 1977. Flood Control and Drainage Master Plan for the San Luis Obispo Creek Watershed.

Governor’s Office of Planning and Research, California Energy Commission, and California Natural Resources Agency. 2018a. California’s Fourth Climate Change Assessment. ———. 2018b. California’s Fourth Climate Change Assessment: Central Coast Region Report.

Intergovernmental Panel on Climate Change. 2014. Climate Change 2014 Synthesis Report:

Approved Summary for Policymakers.
———. 2018. Special Report: Global Warming of 1.5 °C
Jenson, J. 1998. Mapping social cohesion: the state of Canadian research. Canadian Policy Research Networks Study No. F-03.

The Nature Conservancy 2014
NOAA 2021
OEHHA. See California Office of Environmental Health Hazard Assessment.

Questa Engineering Corporation. 2003. Waterway Management Plan. Prepared for the City of San Luis Obispo Department of Public Works and the County of San Luis Obispo Flood Control District – Zone 9.

Ramin, B., and Svoboda, T. 2009. Health of the homeless and climate change. Journal of Urban Health, 86(4), 654-664.

Rappold, A. G., J. Reyes, G. Pouliot, W. E. Cascio, and D. Diaz-Sanchez. 2017. Community Vulnerability to Health Impacts of Wildland Fire Smoke Exposure. Environmental Science and Technology.

Rodin, Judith. 2014. The Resilience Dividend: Managing Disruption, Avoiding Disaster, and Growing Stronger in an Unpredictable World.

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San Luis Obispo County. 2019 (October). Annex G: City of San Luis Obispo Community Profile.

Available: https://www.slocounty.ca.gov/getattachment/f97614f4-39a1-4819-810e4d7b637a5507/San-Luis-Obispo-County-Annexes-Municipalities-A-G.aspx. Accessed August 24, 2020.

San Luis Obispo County 2019a (ch.8)
San Luis Obispo County 2019b
Sailor, D. J. 2011. A Review of Methods for Estimating Anthropogenic Heat and Moisture Emissions in the Urban Environment. International Journal of Climatology 31:189–199.

Schwartz, M. W., N. Butt, C. R. Dolanc, A. Holguin, M. A. Moritz, M. P. North, H. D. Safford, N.

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Science Advances 2(4): e1501344.

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DECEMBER 2021
Climate Change Hazards
and Vulnerabilities Report
City of San Luis Obispo
990 Palm Street
DRAFT
San Luis Obispo, CA 93401

DRAFT

20200048.01
Resilient SLO: Climate Change Hazards and
Vulnerabilities Report
Prepared for:

City of San Luis Obispo
990 Palm Street
San Luis Obispo, CA 93401
Prepared by:

Ascent Environmental
455 Capitol Mall, Suite 300
Sacramento, CA 95814
Authors
Ascent: Angie Xiong, Kai Lord-Farmer,
and Honey Walters
Fehr & Peers: Marshall Ballard,
Charlie Coles, and Taylor Whitaker
cbec: Chris Bowles, Luke Tillmann,
and Michael Founds
DRAFT
December 2021

DRAFT

City of San Luis Obispo i
Climate Change Hazards and Vulnerability Report

TABLE OF CONTENTS
Section Page
LIST OF ABBREVIATIONS ......................................................................................................................................................................... IV 1 INTRODUCTION........................................................................................................................................................................1-1

1.1 Climate Change Overview..............................................................................................................................................1-2

1.2 What is Resilience?............................................................................................................................................................1-3 2 CLIMATE HAZARDS ASSESSMENT .......................................................................................................................................2-1

2.1 Vulnerability Assessment Methodology....................................................................................................................2-1

2.2 Social Vulnerability and Environmental Justice...................................................................................................... 2-7

2.3 Temperature and Extreme Heat Analysis............................................................................................................... 2-18

2.4 Long-Term Drought Analysis .....................................................................................................................................2-38

2.5 Wildfire Analysis..............................................................................................................................................................2-46

2.6 Precipitation and Flooding Analysis.........................................................................................................................2-69 3 VULNERABILITY SCORING SUMMARY ................................................................................................................................3-1 4 REFERENCES.............................................................................................................................................................................. 4-1 Appendices
Appendix A –
Figures
Figure 1 California Adaptation Planning Guide Adaptation Planning Phases ................................................................1-1 Figure 2 California Adaptation Planning Guide Vulnerability Assessment Process ....................................................2-2 Figure 3 Representative Concentration Pathway Used in Global Climate Modeling.................................................2-4 Figure 4 Low-Income Communities as Defined under Assembly Bill 1550 ...................................................................2-9 Figure 5 Regionally-Defined Disadvantaged Communities in the City of San Luis Obispo .................................. 2-12 Figure 6 Census Tracts in the City of San Luis Obispo ....................................................................................................... 2-13 Figure 7 Location and Relative Density of Homeless Encampments in the City of San Luis Obispo ..................2-17 Figure 8 City Resident’s Climate Concern by Age................................................................................................................ 2-18 Figure 9 Climate -Related Hazard Impacts on Community Organizations in the City of San Luis Obispo................................................................................................................................................................................ 2-19 Figure 10 Average Annual Maximum and Minimum Temperatures in the City (1926-2018)...................................2-20 Figure 11 Changes in Annual Average Temperature in San Luis Obispo County through 2099........................... 2-21 Figure 12 Urban Heat Island Effect and Tree Cover in the City .........................................................................................2-26 Figure 13 Youth and Elderly Populations and Urban Heat Island Severity in the City...............................................2-29 Figure 14 Asthma Rate Prevalence and Urban Heat Island Severity in the City ..........................................................2-30 Figure 15 Low-Income Areas and Urban Heat Island Severity in the City .....................................................................2-33 Figure 16 Relative Changes in Extreme Heat by 2050 ..........................................................................................................2-34 Figure 17
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Figure 18 Projected Drought Conditions between 2051 and 2070 for San Luis Obispo County ...........................2-39 Figure 19 Wildfire Hazard Severity Zones In and Near the City of San Luis Obispo with Critical Facilities........2-47 Figure 20 Change in Average Annual Maximum Temperature in San Luis Obispo County through 2099........2-48 Figure 21 Biophysical and anthropogenic determinants of wildfire................................................................................. 2-51 Figure 22 Changes in the WUI areas within the City 2001-2016 ........................................................................................2-53 Figure 23 Wildfire Hazard Severity Zones and Percent of No Vehicle Household per Block Group....................2-56 Figure 24 Share of Older Adults and Youth and Fire Hazard Severity Zone in the City ...........................................2-58 Figure 25 SLOCOG Identified Disadvantaged Communities and Fire Hazard Severity Zone in the City ............2-59 Figure 26 Low-Income Populations and Fire Hazard Severity Zone in the City...........................................................2-60 Figure 27 Homeless Encampments and Fire Hazard Severity Zone in the City ........................................................... 2-61 Figure 28 Potential PG&E PSPS Events per Year by Month ................................................................................................2-62 Figure 29 California Public Utility Commission Fire Threat Map .......................................................................................2-63 Figure 30 City Resident’s Wildfire and Wildfire Smoke Concern and Impact ...............................................................2-65 Figure 31 HEC-RAS Hydraulic Model Extent.............................................................................................................................2-73 Figure 32 Flood Depth: Full Extent - Q100 (Historic) .............................................................................................................2-76 Figure 33 Flood Depth: SLO-Stenner - Q10 (Historic) Flood Depth - Q100 (Historic)................................................2-77 Figure 34 Flood Depth: SLO-Stenner - Q10 (Future 2070-2099 – RCP 8.5)...................................................................2-78 Figure 35 Flood Depth: SLO-Stenner - Q100 (Historic).........................................................................................................2-79 Figure 36 Flood Depth: SLO-Stenner - Q100 (Future 2070-2099 – RCP 8.5)................................................................2-80 Figure 37 Flood Depth: SLO-Prefumo - Q10 (Historic) ......................................................................................................... 2-81 Figure 38 Flood Depth: SLO-Prefumo - Q10 (Future 2070-2099 – RCP 8.5).................................................................2-82 Figure 39 Flood Depth: SLO-Prefumo - Q100 (Historic).......................................................................................................2-83 Figure 40 Flood Depth: SLO-Prefumo - Q100 (Future 2070-2099 – RCP 8.5)...............................................................2-84 Figure 41 City Transportation Assets Impacted by Flooding..............................................................................................2-88 Figure 42 Transit Assets Impacted by Flooding.......................................................................................................................2-90 Figure 43 Census Block Groups with No Vehicles per occupied housing unit.............................................................2-93 Figure 44 Access from Census Block Group Centroid to City Gateways ........................................................................2-95 Figure 45 Access from Census Block Group Centroid to City Evacuation Centers .....................................................2-96 Figure 46 Access from Census Block Group Centroid to City Gateways with 100 Year Flood ................................2-97 Figure 47 Access from Census Block Group Centroid to City Evacuation Centers with 100 Year Flood .............2-98 Figure 48 Access from Census Block Group Centroid to City Gateways with 500 Year Flood................................2-99 Figure 49 Access from Census Block Group Centroid to City Evacuation Centers with 500 Year Flood...........2-100 Figure 50 Disadvantaged Communities and 100-year and 500-year Flood Plains ...................................................2-102 Figure 51 Low-Income Areas and Flood Plains in the City ................................................................................................2-103 Figure 52 Hazardous Material Clean Up Sites and Flood Plains in the City ................................................................2-104 Figure 53 Location and Relative Density of Homeless Encampments in the City of San Luis Obispo ...............2-105 Figure 54
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Tables
Table 1 Potential Impact Scoring................................................................................................................................................2-6 Table 2 Adaptive Capacity Scoring ............................................................................................................................................2-6 Table 3 Potential Impact Summary............................................................................................................................................ 2-7 Table 4 City Demographics by Sex, Race, and Age.............................................................................................................. 2-7 Table 5 Housing Cost Characteristics........................................................................................................................................2-8 Table 6 Gross Rent as a Percentage of Monthly Household Income ............................................................................2-8 Table 7 Languages Spoken by City Residents...................................................................................................................... 2-10 Table 8 Social Vulnerability and Environmental Justice Indicators by Census Tract............................................... 2-14 Table 9 Changes in Average Annual Temperature in City of San Luis Obispo ........................................................2-20 Table 10 Changes in Extreme Heat Events in City of San Luis Obispo ..........................................................................2-22 Table 11 Changes in building energy use through 2099 ...................................................................................................2-27 Table 12 Heat Health Events through 2099 ............................................................................................................................ 2-31 Table 13 Changes in Average Annual Precipitation and 5-Year Storm Event in San Luis Obispo County .......2-39 Table 14 Changes in Annual Average Area Burned in San Luis Obispo County........................................................2-49 Table 15 Percent Change in Developed Area for WUI Areas within the City 2001-2016.........................................2-52 Table 17 Changes in Average Annual Precipitation in City of San Luis Obispo .........................................................2-70 Table 18 Climate-induced Changes in Peak Stream Flow for the San Luis Obispo Creek Watershed...............2-74 Table 19 Change in Connected Floodplain Areas for 9 Analysis Regions from Historic to Future (median) Conditions. .....................................................................................................................................................2-85 Table 20 Change in Connected Floodplain Depths for 9 Analysis Regions from Historic to Future (median) Conditions. .....................................................................................................................................................2-85 Table 21 Transit Stops Impacted by Storm Event .................................................................................................................2-89 Table 22 Flood Year and Longest Distances to City Gateways and Evacuation Centers........................................2-101 Table 23 Summary of Existing Plans and Reports ....................................................................................................................3-1 Table 24 Summary of Vulnerability Scoring...............................................................................................................................3-1 DRAFT

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LIST OF ABBREVIATIONS
°F Fahrenheit
°C Celsius
Q10 10-year storm event
Q100 100-year storm event
APG Adaptation Planning Guide
AR Atmospheric River
CALFIRE Department of Forestry and Fire Protection
Cal Poly California Polytechnic State University at San Luis Obispo Caltrans California Department of Transportation
CDC Center for Disease Control and Prevention
CDD Cooling Degree Day
CDHP California Department of Public Health
CHAT California Heat Assessment Tool
County County of San Luis Obispo
City City of San Luis Obispo
FEMA Federal Emergency Management Agency
GHG greenhouse gas
GIS geographic information system
HDD Heating Degree Day
HHE Heat Health Events
HMP San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan IDF intensity, duration, frequency
IPCC Intergovernmental Panel on Climate Change
OES Office of Emergency Services
OPR Governor’s Office of Planning and Research
PG&E Pacific Gas and Electric
PCTP Pacific Coast tick fever
ppm Parts Per Million
PSPS Public Safety Power Shutoff
RCP Representative Concentration Pathways
Report Climate Change Hazards and Vulnerabilities Report RTA
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San Luis Obispo Regional Transit Authority

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SB Senate Bill
SLO San Luis Obispo
SR State Route
SWAT Soil and Water Assessment Tool
UHI Urban Heat Island
UWMP Urban Water Management Plan
VHFHSZ Very High Fire Hazard Severity Zones
WUI wildland-urban interface
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1 INTRODUCTION
The climate is changing, with the pace of global warming being rapidly increased by human activities. Human-caused climate change is likely to increase the global average temperature 1.5 degrees Celsius (°C) (2.7° Fahrenheit [F]) between 2030 and 2052 (IPCC 2018). While the global community continues to reduce greenhouse gas (GHG) emissions moving forward, historic global GHG emissions have already solidified permanent changes to the environment, bringing with it substantial changes to the world, the state, the region, and the City of San Luis Obispo (City). Acknowledging the severity of these impacts and the importance of preparedness, the City of San Luis Obispo City Council has identified climate adaptation and resilience as a top priority.

The Climate Change Hazards and Vulnerabilities Report (Report) is the City’s primary climate change vulnerability assessment summary document. The vulnerability assessment included in the Report identifies the City’s exposure to the effects of climate change, identifies the sensitivity of population groups and community assets to specific climaterelated hazards, analyzes potential climate change impacts, and assesses the City’s existing capacity to address those impacts. The Report also serves to summarize and synthesize more detailed work being done that focuses on specific climate-hazards, City resources, or specific climate-related impacts. This Report is a component of the City’s Resilient SLO project, a community-led initiative to improve community resilience to the worsening impacts of climate change.

It is intended to help identify the specific climate vulnerabilities and impacts that are projected to occur in the City and assist in the development of a comprehensive set of climate adaptation strategies that will be incorporated into the General Plan Safety Element in compliance with Senate Bill (SB) 379, Government Code section 65302(g)(4).

SB 379, adopted in 2015, requires jurisdictions to integrate climate change adaptation into the general plan safety element development and update process. The law requires all cities and counties to update their safety elements to include the assessment of climate change vulnerabilities and adaptation strategies upon the jurisdiction’s next safety element update. Under Government Code Section 65040.2, the Governor’s Office of Planning and Research is charged with periodically updating and adopting the State General Plan Guidelines to guide the preparation of general plans for all cities and counties in California. The 2017 update to the General Plan Guidelines Safety Element chapter includes an additional focus on preparing communities for long-term climate change impacts (OPR 2017).

The Resilient SLO project follows the four-phase adaptation planning process included in the California Adaptation Planning Guide, as shown in Figure 1. This Report serves as the culmination of Phase 2 of the project, assessing the unique vulnerabilities of the SLO community to the impacts of climate change. The findings of this Report will support development of a set of adaptation strategies (Phase 3) to be included in City’s Safety Element Update.

Figure 1 California Adaptation Planning Guide
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Adaptation Planning Phases

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This Report was developed using the best available information regarding climate change projections for the City and the Central Coast region, relevant information on current efforts to adapt to climate change, and best practices and guidance provided by the State and other sources specific to climate adaptation planning. The primary resources used in developing this Report are:
 California Adaptation Planning Guide (Cal OES 2019);
 Safeguarding California Plan: California’s Climate Adaptation Strategy (CNRA 2018);  Cal-Adapt 2.0;
 California’s Fourth Climate Change Assessment (statewide report) (OPR et al. 2018a, 2018b);  California’s Fourth Climate Change Assessment: Central Coast Region Report (2018b);  State of California General Plan Guidelines (OPR 2017);  State Adaptation Clearinghouse in the Integrated Climate Adaptation and Resiliency Program;  San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan (San Luis Obispo County 2019a; and  California Department of Transportation (Caltrans) District 5 Climate Change Vulnerability Assessment Summary Report (Caltrans 2019a); and associated Technical Report (Caltrans 2019b).

1.1 CLIMATE CHANGE OVERVIEW
The combustion of fossil fuels, among other human activities since the Industrial Revolution in the 19th century, has introduced GHGs into the atmosphere at an increasingly accelerated rate. Significantly elevated levels of GHG emissions have intensified the greenhouse effect and led to a trend of unnatural warming of the Earth’s climate, known as global climate change or global warming. The largest source of GHG emissions from human activities is the burning fossil fuels for electricity, heat, and transportation. Climate change, in recent decades, has become a priority issue on an international, national, and local scale as recent climate data reveal more extreme weather patterns, increased average global temperatures, and the rapid melting of the Earth’s Artic and Antarctic poles and glaciers.

The global average temperature is expected to increase by 3.7 degrees Celsius (°C) (6.7 to 8.6 degrees °F) by the end of the century unless additional efforts to reduce GHG emissions are made (IPCC 2014). Human-caused climate change is currently increasing the global average temperature by approximately 0.2°C (0.36 °F) per decade due to past and ongoing emissions. While the global average temperature has already begun to increase, the Intergovernmental Panel on Climate Change (IPCC) has identified an increase of 1.5 degrees °C (2.7 F°) as a threshold that, if crossed, push many natural systems that sustain life past a dangerous turning point with a more limited ability to recover (IPCC 2018). Depending on future GHG emissions, average annual maximum daily temperatures in California are projected to increase between 4.4 and 5.8°F by 2050 and by 5.6 to 8.8°F by 2100 unless significant reductions in GHG emissions are made (OPR et al. 2018a). Temperature changes in the Central Coast region are expected to be even more significant, with projections of a 7 to 8°F increase by the end of the century (OPR et al 2018b) if global emissions continue on their current trend.

The state and the City have already begun to experience extreme weather effects, the frequency and intensity of which have been worsened by climate change (OPR et al. 2018a). Extreme weather effects such as volatility in precipitation, increased average temperatures, and increased frequency of extreme heat events have led to increases in the frequency and intensity of human health and natural hazard impacts such as wildfires, droughts, and changes to regional water supplies.

While the scope of the Resilient SLO project is intended to focus on local and regional climate impacts, it is important to recognize that larger scale climate impacts to natural and manmade systems may affect the SLO community and should be recognized.

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In September 2021, the IPCC’s Sixth Assessment Report was released. The findings highlight key new insights into the importance of global climate tipping points, a threshold that, when exceeded, can lead to large changes in the state of the climate system with one impact rapidly leading to a series of cascading events with vast repercussions. This new report is set to contain the body’s strongest warnings yet on the subject.

Importantly, the draft report notes that, in terms of solutions, “We need transformational change operating on processes and behaviors at all levels: individual, communities, business, institutions and governments. We must redefine our way of life and consumption (Earth.org 2021)” In 2020, the City adopted the Climate Action Plan for Community Recovery with the goal of achieving carbon neutrality by 2035 while focusing on using resources more effectively, improving community equity and well-being, and developing an economy that is set to recover from the impacts of COVID-19. The intent of the science-based goal is to play a proportional role in achieving global carbon neutrality and inspire similar action regionally, statewide, nationally and internationally so that global warming is kept between 1.5°C and 2°C. While it remains imperative that the City implement the Climate Action Plan and reduce GHG emissions to achieve carbon neutrality, it is equally important for communities to invest in climate change adaptation planning to improve resilience to extreme climate events that are projected over the 21st century.

1.2 WHAT IS RESILIENCE?
Resilience is the capacity of any entity—an individual, a community, an organization, or a natural system—to prepare for disruptions, to recover from shocks and stresses, and to adapt and grow from a disruptive experience (Rodin 2014). As has been demonstrated by recent catastrophic wildfire seasons, the more frequent severe storms, the prolonged drought periods and the longer and hotter summer seasons, the effects of climate change are already occurring in California and in the Central Coast region. Planning for how to mitigate and adapt to these impacts is important to ensure the City is able to continue to prosper as a community.

Importantly, the concept of creating community resilience goes beyond preparing for the physical environment for future impacts from climate change and now considers and prioritizes the physical and psychological health of the population, social and economic equity, and well-being of the community. Developing a resilient community requires effective risk communication, integration of organizations (both governmental and community-based) in climate adaptation planning, response, and recovery, and supporting social connectedness for resource exchange, cohesion, response, and recovery efforts (CNRA 2018). In an effort to identify how the City can not only adapt to climate impacts but become more resilient and thrive in a more volatile and unpredictable climate, this Report identifies and discusses both the physical and social vulnerabilities the City has to the impacts of climate change in an effort to better support the adaptation strategy development process.

The following section (Climate Hazards Assessment) of the Report provides a detailed assessment of four key climate-related hazards (Temperature and Extreme Heat; Long-Term Drought; Wildfire; and Precipitation and Flooding) that are projected to affect the City. Section 3 (Vulnerability Scoring Summary) then provides a summary and ranking of the four climate-related hazards based on the findings of the assessment in Section 2.

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2 CLIMATE HAZARDS ASSESSMENT
This section provides a comprehensive assessment of the City’s vulnerabilities to climate change. It identifies and characterizes climate-related hazards and other climate effects that are anticipated to affect the City, its residents, and visitors. The analysis in this section is organized into four distinct hazard categories. These categories are:
 Temperature and Extreme Heat
 Long-Term Drought
 Wildfire
 Precipitation and Flooding
It is important to recognize that the City is exposed to other natural and human-made hazards such as seismic events or hazardous waste. However, these hazards are addressed other planning documents in the City’s Safety Element and the County Multi-Jurisdictional Hazard Mitigation Plan. This Report assesses hazards that are going be affected and exacerbated by climate change, focusing specifically on how these hazards are likely to increase in frequency and severity.

2.1 VULNERABILITY ASSESSMENT METHODOLOGY
For each of the four hazard areas listed above, the analysis follows the vulnerability assessment process outlined in the California Adaptation Planning Guide and is composed of the four steps outlined below in Figure 2. The following discussion provides an overview of the methodology used for each step of the vulnerability assessment process and provides context for the discussions of each climate-related hazard in Sections 2.2 through 2.5.

2.1.1 Exposure
The purpose of this step is to understand to what degree the City is vulnerable to impacts from each climate-related hazard under historic conditions and how changes in climate variables are projected to affect the hazard. A summary of the City’s existing exposure to each hazard is provided using information from the Resilient SLO Baseline Conditions Report (City of San Luis Obispo 2021a).

According to the work of IPCC and research conducted by the State of California, partner agencies, and organizations, climate change is already affecting and will continue to affect the physical environment throughout California, including the City. To identify the local impacts of climate change in California, the California Energy Commission, and the University of California, Berkeley Geospatial Innovation Facility developed the scenario planning tool Cal-Adapt. The Cal-Adapt tool uses global climate simulation model data downscaled to a local and regional resolution to identify localized impacts from various climate metrics. Developers of the Cal-Adapt tool selected four priority global climate models to include in projections provided in the tool. This analysis uses the average of these four models to identify changes in temperature and extreme heat events.

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Source: Cal OES 2019.

Figure 2 California Adaptation Planning Guide Vulnerability Assessment Process DRAFT

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This analysis uses Cal-Adapt data to evaluate changes in several key climate variables projected to affect the City. The analysis also identifies at what point over the next approximately 80 years (2021–2099) changes in these variables will occur and at what magnitude. This exposure analysis uses three time periods to analyze changes in key climate variables. Due to annual fluctuations in climate variables, climate data is typically measured on a 30-year or longer timescale. Climate variables measured over a shorter time period is typically less accurate and not reflective of longterm averages (NOAA 2018). The time periods established for this analysis are 30-year time intervals to gather accurate data on average changes in the climate. This results in overlap among some time periods and a gap between 2064 and 2070. However, the three time periods used in this analysis have been chosen to align with time periods used in the Cal-Adapt tool and are intended to provide snapshots of how certain climate variables will change over the 21st century. The three time periods are:
 Near-term (2021–2050),
 midterm (2035–2064), and
 late-century (2070–2099).

The California Adaptation Planning Guide (APG), as well as the Governor’s Office of Planning and Research’s guidance for State agencies (OPR 2018), provide guidance on choosing appropriate Representative Concentration Pathways (RCP) scenarios to be included in vulnerability assessment analyses. For analysis of impacts through 2050, the APG suggests using a conservative approach and selecting the high emissions scenario, to assume a worst-case scenario but notes that impacts by 2050 under the medium and high scenarios will vary based on local context. As recommended by the APG, this analysis evaluates near-term and midterm climate change effects and their associated impacts under the high emissions scenario, as this takes a conservative approach and assumes a worst-case scenario.

Additionally, as observed in the Cal-Adapt data, changes in climate variables during the near-term and midterm periods are similar under both the medium and high emissions scenarios. Because long-term global GHG emissions trends are less certain and climate impacts vary more considerably between scenarios during this period, a discussion of both the medium and high emissions scenarios is included for this timescale (OPR et al 2018a).

FORECASTING ASSUMPTIONS
The projected effects of climate change over the next century will vary depending on global GHG emissions trends.

The Cal-Adapt tool includes global climate simulation model data from two emissions scenarios, known as RCPs, that were used in the IPCC’s Fifth Assessment Report. The RCPs represent scenarios that estimate the level of global GHG emissions through 2099. The RCP scenarios used in the Cal-Adapt tool and discussed in the California Adaptation Planning Guide are the RCP 8.5 (high emissions) scenario, which represents a business-as-usual future emissions scenario in which global GHG emissions continue to rise through the rest of the century, peaking around 2099, and resulting in atmospheric CO2 concentrations exceeding 900 parts per million (ppm) by 2100, and the RCP 4.5 (medium emissions) scenario, which represents a lower GHG emissions future and likely the best-case scenario for climate impacts, under which GHG emissions would peak in 2040 and then decline through the rest of the century, resulting in a CO2 concentration of about 550 ppm by 2100. The RCP trends assumed in the analysis are illustrated in Figure 3.

Figure 3 also includes other global emissions scenarios that have been analyzed by the IPCC but are not included in the Cal-Adapt tool. The RCP 4.5 and 8.5 scenarios have been included in the Cal-Adapt tool because they represent two important scenarios for future planning. The RCP 8.5 scenario is included to illustrate what climate impacts will look like if no future action is taken to reduce global emissions. The RCP 4.5 scenario is included as a potential bestcase scenario for reducing global GHG emissions. The emissions scenarios depend on global GHG emissions trends in the future and the efficacy of global GHG reduction strategies proposed by the internation DRAFT
al community.

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Notes: CO2= carbon dioxide; ppm = parts per million; PgC = one billion metric tons of carbon; RCP = Representative Concentration Pathway.

Source: Goosse et al. 2010
Figure 3 Representative Concentration Pathway Used in Global Climate Modeling Cal-Adapt also includes 10 global climate models, downscaled to local and regional resolution using the Localized Constructed Analogs statistical technique. Four of these models have been selected by California’s Climate Action Team Research Working Group as priority models for research contributing to California’s Fourth Climate Change Assessment. Projected future climate from these four models can be described as producing:
 A warm/dry simulation (HadGEM2-ES),
 A cooler/wetter simulation (CNRM-CM5),
 An average simulation (CanESM2), and
 The model simulation that is most unlike the first three for the best coverage of different possibilities (MIROC5).

2.1.2 Sensitivity and Potential Impacts
This step summarizes population groups and community assets that are sensitive to localized climate change effects.

Changes in climate-related hazards are generally projected to increase in severity, with the potential for climate change to generate new impacts that communities have not experienced historically. Using historical data, research from regional and statewide reports on climate impacts, and input from stakeholders on which sensitive populations and assets should be prioritized for the analysis, this step identifies sensitive populations and assets and assesses how they are likely to be impacted by climate change.

As part of the community outreach process for the Resilient SLO project, a specific set of priority assets and functions were identified for each of the three categories described above. The priorities identified for these three categories were developed through a set of working group meetings based on the three categories and confirmed by the DRAFT

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Resilience Roundtable, a community-led advisory body that is helping the City guide the approach and focus of the Resilient SLO project and the City’s Safety Element update. The priorities identified through the community outreach process were then supplemented using hazard mitigation and emergency operation planning resources developed previously the by City and the County. The priorities identified by the working groups and additionally identified priority sensitive populations and assets are list below under each category.

The set of sensitive populations, assets, and community functions analyzed in this step are organized into the following three general categories.
 Natural Systems – This category includes systems or system components of the natural environment (e.g., forests and grasslands, flora and fauna, stream health) in the City and the surrounding region that are critical to overall ecosystem health.
o Passive Recreation and Trails (Working Group)
o Open Space and Ecosystem Functions (Working Group)
o Agricultural Production and Industry (Working Group)
o Invasive species and secondary impacts (Working Group) o Water (water supply, stormwater) (Working Group)
o Urban Tree Canopy (Additional Priority)
 Built Environment – This category includes the physical assets that comprise the City’s built environment (e.g., roadway network, buildings, utility systems, stormwater management system) that are critical to supporting normal community functions in the City.
o Evacuation Routes and Mobility (Working Group)
o Telecommunication Systems (Working Group)
o Building Stock and Energy Efficiency (Working Group)
o Community Spaces for Gathering (Working Group)
o Energy Infrastructure and Outages (Working Group)
o Wildland Urban Interface (Additional Priority)
o Water Supply Reservoirs (Additional Priority)
o Stormwater Management System (Additional Priority)
 Community Resilience – This category includes human-focused systems that provide essential services to residents and visitors in the City and are critical to maintaining normal community functions (e.g., economic activity, healthcare system, schools).
o Food Systems and Supply Chains (Working Group)
o Emergency Communications/Misinformation (Working Group) o Personal Resilience (Health and Finances) (Working Group) o Governance/Trust (Working Group)
o Community Organizations and Social Networks (Working Group) o Climate Vulnerable Populations (Additional Priority)
These three categories, marked by their signature color shown above, are discussed throughout this report in relation to each hazard.

While these three categories are intended to encompass important components of the City and its functions, impacts in these categories are likely to affect one another and result in secondary or compounding impacts. Alongside the discussion of potential impacts, the sections below that discuss each hazard also includes a discussion of how some of the various impacts in these
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Based on guidance from the California Adaptation Planning Guide, potential impacts from each of the four climaterelated hazards listed above are rated on a qualitative scale comprised of Low, Medium, and High ratings. A description of each qualitative rating for potential impacts is provided in Table 1.

Table 1 Potential Impact Scoring
Score Potential Impact Scoring Description
Low (1) Impact is unlikely based on projected exposure; would result in minor consequences to public health, safety, and/or other metrics of concern.

Medium (2) Impact is somewhat likely based on projected exposure; would result in some consequences to public health, safety, and/or other metrics of concern.

High (3) Impact is highly likely based on projected exposure; would result in substantial consequences to public health, safety, and/or other metrics of concern.

Source: CalOES 2020

2.1.3 Adaptive Capacity
Adaptive capacity is defined as the ability of systems, institutions, humans, and other organisms to adjust to potential damage, to take advantage of opportunities, or to respond to consequences (IPCC 2014). The City, partner agencies, and community organizations in the City have already taken substantial steps to build resilience and protect the City from existing climate-related hazards. The purpose of this step is to analyze and summarize the City’s current adaptive capacity to address and reduce risk from future climate impacts. This step includes a review of the City’s existing policies, plans, programs, and resources, as well as those from relevant regional and State agencies and organizations that provide an assessment of the City’s current ability to reduce vulnerability to hazards and adapt to climate change over the 21st century. Although the City has already taken comprehensive steps to reduce risk from these hazards, climate change is projected to increase the frequency and severity of climate-related hazards in the future and may exceed the City’s current capacity to address these hazards or may pose novel threats the City has not encountered historically.

Based on the analysis of current resources and efforts undertaken by the City or partner agencies, the City’s adaptive capacity for each climate-related hazard is rated Low, Medium, or High. High adaptive capacity indicates that measures are already in place to address the points of sensitivity and impacts associated the specific climate-relate hazard, while a low rating indicates a community is unprepared and requires major changes to address specific sensitivities. Adaptive capacity ratings are described in Table 2.

Table 2 Adaptive Capacity Scoring
Score Adaptive Capacity Scoring Description
Low (3) The community lacks capability to manage climate impact; major changes would be required.

Medium (2) The community has some capacity to manage climate impact; some changes would be required.

High (1) The community has high capacity to manage climate impact; minimal to no changes are required.

Source: CalOES 2020

2.1.4 Vulnerability Scoring
This step determines the City’s priority climate vulnerabilities through a vulnerability scoring process. The City’s vulnerability to each identified impact is assessed based on the magnitude of risk to and potential impacts on City while considering the current adaptive capacity to mitigate for these impacts. Based on the ratings of potential impacts and adaptive capacity, an overall vulnerability score has been assigned to each climate-related hazard category. This scoring helps the City better understand which climate hazards pose the greatest threat and should be prioritized for future planning efforts. Table 3 presents the rubric used to determine overall vulnerability scores based on the ratings for potential impacts and adaptive capacity.

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Table 3 Potential Impact Summary
Vulnerability Score
Adaptive Capacity
Low 3 4 5
Medium 2 3 4
High 1 2 3
Low Medium High
Potential Impacts
Source: CalOES 2020; adapted by Ascent Environmental in 2021 Vulnerability scoring for each climate change effect identified and evaluated in Sections 2.2 through 2.5 is included in Section 3 which also provides a summary of all climate-related hazards analyzed.

2.2 SOCIAL VULNERABILITY AND ENVIRONMENTAL JUSTICE
This section provides an overview of the sociodemographic characteristics of the City and highlights specific social vulnerabilities and environmental justice issues that may place certain populations or areas in the City at a disproportionately higher risk of climate change related impacts. The information in this section is then used, as appropriate, in each hazard discussion, highlighting where and how certain populations may be at increased risk from climate impacts.

Certain populations in urban areas are particularly vulnerable to a variety of hazards that are likely to be exacerbated by climate change. Vulnerabilities can include being disproportionately exposed to hazards and environmental pollution; being more sensitive to impacts because of preexisting health conditions; or having less resources or opportunities to prepare for and recover from hazard impacts. Vulnerable populations often include persons over the age of 65, infants and children, communities of color, individuals with chronic health conditions (e.g., cardiovascular disease, asthma), low-income populations, athletes, and outdoor workers (CDC 2019). More broadly, any trait that would limit or prevent people from avoiding a hazard, seeking medical attention, or obtaining essential food, supplies, and/or care in an emergency would make them vulnerable to hazards.

2.2.1 Population Overview
The U.S. Census bureau estimates the City’s population to be 47,459 persons as of July 2019 (U.S. Census Bureau 2019).

Table 4 illustrates the City’s demographics by sex, race, and age according to the U.S. Census. As shown, the majority of residents identify as white with those identifying as Hispanic being the second largest demographic group. In terms of youth and elderly populations, 29 percent of City residents are either under 18 years or over 65 years old. The City is highly educated: 93 percent of the population over 25 years old has at least a high school degree, and 50 percent of the population over 25 years old has a bachelor’s degree or higher (U.S. Census Bureau 2018).

Table 4 City Demographics by Sex, Race, and Age
Demographic Characteristics City of San Luis Obispo San Luis Obispo County California Population 47,459 283,111 39,512,223
Male 51% 51% 50%
Female 49% 49% 50%
White alone 84% 89% 72%
Hispanic or Latino 18% 23% 39%
Asian alone 6% 4% 16%
Two or more races 4% 4% 4%
Black or African American alone 2% 2% 7%
American Indian and Alaska Native alone
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Demographic Characteristics City of San Luis Obispo San Luis Obispo County California Persons under 5 years 3% 5% 6%
Persons under 18 years 13% 18% 23%
Persons 65 years and older 13% 21% 15%
Source: U.S. Census Bureau 2019

HOUSING COSTS
Overall, the cost of living in the City is high relative to household income. Table 5 provides key information about housing costs in the City. As shown in Table 6, around 57 percent of renters spend 35 percent or more of their income on rent (U.S. Census Bureau 2018). Around 6 percent of all families and 14 percent of families with a female single parent had an income that fell below the poverty level in the span of a year (U.S. Census Bureau 2018).

Table 5 Housing Cost Characteristics
Housing Characteristic Housing Cost
Median monthly cost for owners with a mortgage $2,340
Median monthly cost for renters $1,461 per unit
Median household income $52,740
Source: U.S. Census Bureau 2018
Table 6 Gross Rent as a Percentage of Monthly Household Income Housing Characteristic Percent of Occupied Units
Less than 15 percent 7%
15 to 20 percent 8%
20 to 25 percent 9%
25 to 30 percent 13%
30 to 35 percent 6%
35 percent or more 57%
Source: U.S. Census Bureau 2018
As illustrated in Figure 4, the City has a substantial low-income population, as mapped consistently with definitions provided in Assembly Bill 1550, which defines low-income communities as census tracts with median household incomes at or below 80 percent of the statewide median income or with median household incomes at or below the threshold designated as low income by the California Department of Housing and Community Development’s list of state income limits adopted pursuant to California Code Section 50093. As demonstrated in Figure 4, this population is located primarily in the northern and central parts of the City. It is estimated that Cal Poly State University and Cuesta College students comprise more than one third of the City's population. As a result, students strongly influence the City’s housing supply and demand. As noted in the City’s Housing Element, although often grouped into low-income categories statistically, many students can spend more on housing than income data suggests because of parental support or larger household sizes. By pooling their housing funds, groups of students can often afford more expensive housing. This contributes to higher rents in San Luis Obispo compared to other parts of the County (City of San Luis Obispo 2020a).

Research has found that housing affordability is one of the strongest predictors of rates of homelessness in a community, with higher median rents leading to higher rates of homelessness and higher rates of sheltered homeless populations. To better understand the issue of homelessness, the U.S. Interagency Council on Homelessness categorizes homeless individuals in three basic groups: chronically homeless (i.e., people who have experienced longterm homelessness), episodic homeless (i.e., people who alternate between permanent housing and supportive housing or shelters), and transitional homeless (i.e., people who become temporarily homeless because of an event, such as loss of employment) (U.S. Interagency Council on Homelessness 2009). There are approximately 482 homeless individuals in the City (City of San Luis Obispo 2020a).

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Source: CalEPA 2020
Figure 4 Low
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DISABILITY STATUS
Individuals with disabilities, especially those who are also unemployed or underemployed, are especially vulnerable to climate hazards largely because they, along with youth and senior populations, often rely heavily on family or caretakers for transportation and other basic needs (e.g., taking medications, cooking food). Around 9 percent of the City’s total civilian noninstitutionalized population has a disability, with the majority of these people 65 years and over. Around 35 percent of people 65 years and over in the city have reported having a disability (U.S. Census Bureau 2018).

LANGUAGE
Cultural and linguistic isolation can make it difficult for people to access or understand important information regarding preparing for and responding to emergency situations. Approximately 6 percent of the City’s population primarily speaks a language other than English and reports that they can speak English less than “very well” (U.S.

Census Bureau 2018). Table 7 includes information about languages spoken in the City as well as what percentage of residents that speak another language do not speak English “very well” and may experience linguistic isolation.

Table 7 Languages Spoken by City Residents
Language Spoken Percentage of Population Percentage of population that speak English less than “very well”
Speak only English 83% n/a
Speak Spanish 11% 33%
Other Indo-European Language 2.5% 26%
Asian-Pacific Island Language 3% 45%
Other Languages 0.5% 21%
Notes: n/a = not applicable
Source: U.S. Census Bureau 2018

2.2.2 Social Vulnerability Mapping and Environmental Justice While the City includes sociodemographic characteristics that may place residents at increased risk to climate impacts, it is important to recognize that these social vulnerabilities are not spread evenly across the City. Populations with specific vulnerabilities may be concentrated in key areas of the City and have the potential to overlap with key climate related hazards that place these populations at a disproportionate level of risk from climate impacts. In general, low-income residents, communities of color, tribal nations, and immigrant communities have disproportionately experienced some of the greatest environmental burdens and related health problems throughout the history of the U.S. and in California. These historic inequities are, in the majority of cases, not a coincidence but a result of inappropriate zoning and negligent land use planning, intersecting structural inequalities, failure to enforce proper zoning or conduct regular inspections, deed restrictions and other discriminatory housing and lending practices, limited political and economic power among certain demographics, the prioritization of business interests over public health, development patterns that tend to concentrate pollution and environmental hazards in certain communities, and the placement of economic and environmental benefits in areas outside of disadvantaged communities (California Environmental Justice Alliance 2017).

Based on the State’s definition of disadvantaged communities, no census tracts within the San Luis Obispo region are designated as disadvantaged communities. However, the San Luis Obispo Council of Governments (SLOCOG) has created a regional definition of disadvantaged communities to better compete for grant funding, distribute funds more equitably, and meet the state and federal environmental justice requirements. The Disadvantaged Communities Assessment was approved by the SLOCOG Board for use in the 2023 RTP and the 2022 Programming Cycle on June 2nd, 2021.

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In the San Luis Obispo Region, disadvantaged communities are defined as disproportionately burdened areas that are economically distressed and/or historically underrepresented as a part of the local government process. The Disadvantaged Communities Assessment identifies 13 variables that address a wide range of socioeconomic and population-based factors to geographically define these disproportionately-burdened areas. The 13 variables are:
 Racial Minority
 Ethnic Minority
 Disability Status
 Household Income
 Free or Reduced-Price Meals
 Educational Attainment
 Language Proficiency
 Renter Affordability
 Housing Ownership Affordability
 Older Adults: Age 75 Years and Older
 Youth: Age 15 Years and Under
 Households with No Vehicle Available
 Households with No Computing Device Available
Similar to the SLOCOG assessment of disadvantaged communities, the Public Health Alliance of Southern California has developed the California Healthy Places Index (HPI). The California HPI provides an interactive map, graphs, data tables, and a policy guide to examine local health factors and compare local conditions to those across the state.

Climate health vulnerability indicators are built into the HPI by incorporating climate-related hazards data layers into the mapping (e.g., air conditioning access, public transit access); incorporating select climate-resiliency metrics into the HPI score, which combines 25 community characteristics into a single indexed score to describe a community’s overall health; and addressing climate challenges in the policy guide.

The HPI score for the City combines 25 community characteristics across eight areas (i.e., economic, social, education, transportation, neighborhood, housing, clean environment, and health care) into a single indexed score correlated to life expectancy at birth. The HPI score ranking for the combined census tracts in the City places it in the 61st percentile, meaning it has healthier community conditions than 61 percent of other California census tracts. Certain geographic areas and populations may be more vulnerable than others, by identifying these specific populations or geographic areas, the City can work to address these vulnerabilities and, in turn, make the whole community more resilient.

Compared to the City’s overall HPI score, the City is doing particularly well in terms of education, performing better than 78 percent of other California census tracts in preschool enrollment and residents with a bachelor’s degree or higher. However, the City ranks lower in terms of the economic factors score (39th percentile overall), which includes factors such as median household income, unemployment rate, and population with an income exceeding 200 percent of federal poverty level. The City also ranks low in terms of the housing factors score (17th percentile overall), which includes indicators such as low-income homeowners and renters with a severe housing burden (HPI 2020). This summary provides highlights of the City overall HPI score. To see all information on individual indicators, visit the California HPI website (https://map.healthyplacesindex.org/).

Figure 6 below includes the main census tracts that comprise the City. Table 8, which corresponds with Figure 6, includes a set of sociodemographic characteristics for each of the City’s census tracts. Figure 5 also includes the HPI scoring scale for each census tract in the City, highlighting the portions of the City with lower scores that may be more vulnerable to climate impacts. The HPI scores for each census tract can be compared across the state to paint an overall picture of health and well-being in each census tract relative to the rest of California. For example, a census tract HPI score of 21 means that that tract has healthier community conditions than just 21.5 percent of other California census tracts. This means the lower the HPI score equates to, in general, less healthy living conditions and health outcomes for residents and potentially more climate vulnerability.

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Sources: Data received from SLOCOG in 2021 and from CBEC Engineering in 2020, and downloaded from City of San Luis Obispo in 2020 and County of San Luis Obispo in 2020
Figure 5 Regionally Defined
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Disadvantaged Communities in the City of San Luis Obispo

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Sources: Data downloaded from US Census in 2019, City of San Luis Obispo in 2020 and County of San Luis Obispo in 2020 Figure 6 Census Tracts in the City of San Luis Obisp
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Table 8 Social Vulnerability and Environmental Justice Indicators by Census Tract Name
Cal Poly
Neighbo
rhood
North
Monterey
Street and
Johnson
Avenue
Sinsheimer
Neighborh
ood
Downtown
SLO and Mill
Street
Historic
District
South
Downtown
SLO and
Railroad
District
Margarita
Avenue
Neighborhood
Foothill
Boulevard
Neighborhood
Laguna Lake
and Los
Osos Valley
Road
West of
South
Higuera
South Broad
Street
Neighborhood
Census Tract 109.02 110.02 110.01 111.01 111.02 111.03 112 113 115.01 115.03 Healthy Places Index Score 27.6 70.5 72.7 55.5 69.6 37.4 50.9 68.4 60.4 84.6 Latino 12% 9% 16% 15% 16% 25% 10% 18% 17% 9%
Black <1% <1% <1% 2% <1% 2% <1% 0.01 2% <1%
Asian 6% 4% 5% 3% 3% 3% 5% 7% 4% 4%
Poverty Level 80% 51% 30% 49% 42% 50% 59% 38% 32% 22%
Linguistic Isolation 2% 2% 4% 1% 3% 8% 1% 8% 4% 0%
Outdoor Workers <1 2% 2% 4% 4% 3% 2% 3% 5% 2%
Elderly Populations 3% 8% 20% 9% 10% 17% 13% 14% 17% 12% Youth Populations 2% 2% 7% 2% 3% 5% 3% 3% 5% 6%
Disabled Population 3% 4% 12% 7% 11% 11% 8% 10% 15% 7%
Tree Canopy 5% 1% 7% 6% 3% 4% 9% 9% 5% 3%
Park Access 76% 78% 93% 100% 100% 94% 60% 99% 100% 93%
Supermarket Access 33% 67% 30% 83% 99% 40% 58% 53% 92% 32% Renter Housing Cost Burden 70% 42% 22% 29% 25% 35% 70% 34% 11% 41% Active Commuting 31% 20% 11% 35% 23% 21% 22% 13% 9% 6%
CalEnviroScreen Score 9.89 14.99 6.69 11.85 10.95 26.9 15.86 16.58 12.86 10.9 Notes: n/a = not applicable
Source: California Healthy Places Index 2021; U.S. Census Bureau 2017 DRAFT

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Sociodemographic Characteristic Definitions
 Latino – Percent of population in the census tract that identify as Latino.  Black – Percent of population in the census tract that identify as Black or African American.  Asian – Percent of population in the census tract that identify as Asian.  Poverty Level - Percent of people in the census tract earning less than 200% of the federal poverty level (Federal poverty level = $12,880 per individual in 2021). 200% is often used to measure poverty in California due to high costs of living.
 Linguistic Isolation – Percent of households in the census tract that do not have one or more persons 14 years or older who speaks English well.
 Outdoor Workers - Percent of adults (over 16) in the census tract who work outdoors.  Elderly Populations - Percent of population in the census tract under 5 years old.  Youth Populations - Percent of population in the census tract under 5 years old.  Disabled Population - Percent of people in the census tract with access and functional needs (a physical or mental disability).
 Tree Canopy - Percent of land in the census tract has tree canopy (weighted by number of people per acre).  Park Access - Percent of people in the census tract who live within walkable distance (half-mile) of a park or open space greater than 1 acre.
 Supermarket Access - Percent of land in the census tract that reside less than 1/2 mile from a supermarket/large grocery store.
 Renter Housing Cost Burden - Percent of low-income renters in the census tract who pay more than 50 percent of their income on housing costs.
 Active Commuting - Percent of workers (16 years old and older) in the census tract commute to work by transit, walking, or cycling.
 CalEnviroScreen Score – CalEnviroScreen score which identifies communities disproportionately burdened by multiple sources of pollution and with population characteristics that them more sensitive to pollution. An area with a high score is one that experiences a much higher pollution burden than areas with low scores, with scores (0 -100) being compared across all census tracts in the state.

As shown in Figure 6 and Table 8, the city includes several census tracts which include both sociodemographic characteristics and characteristics of the built environment that make the populations in these census tracts more vulnerable to climate-related hazards and may be at a larger disadvantage in their ability to become more resilient to the impacts of climate change. However, as shown in Table 8, other census tracts in the City display specific characteristics that may make those residents particularly vulnerable to certain climate related hazards and should not be overlooked.

Margarita Avenue Neighborhood (Census Tract 111.03) stands out as a particularly vulnerable area of the City and includes the second lowest HPI score and highest CalEnviroScreen score. Notable characteristics of this area that make it particularly vulnerable, compared to the rest of the city, include a high percentage of minority residents, a high percentage of elderly and disabled residents, a high percentage of residents experiencing linguistic isolation, low access to supermarkets and grocery stores, and 50 percent of residents earning less than 200 percent of the federal poverty level. The West of South Higuera neighborhood (Census Tract 115.01) also stands out as a particularly vulnerable area of the City to climate impacts. Notable characteristics of this area that make its residents particularly vulnerable, compared to the rest of the city, include a high percentage of elderly and disabled residents, the highest percentage of outdoor workers in
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vulnerable to climate impacts (Natural Resource Defense Fund 2016) and may not have the same level of access to emergency resources of information.

The analysis of each hazard also takes into account the information on social vulnerabilities presented above to assesses how populations in different areas of the City are vulnerable to specific hazards.

Figure 7 includes the location and relative density of homeless encampments in the city. The city’s homeless population are particularly vulnerable to climate-related hazards with less access to shelter and resources to protect themselves during emergency events (e.g., flooding, heat waves). Similar to the sociodemographic trends prevalent in some areas of the City, which make them particularly vulnerable to climate-related hazards, the locations of the homeless encampments identified in Figure 7 are also identified as areas in the City with particularly vulnerable populations.

2.2.3 Community-Based Adaptative Capacity
As discussed in 2.1.3, adaptive capacity is defined as the ability of systems, institutions, humans, and other organisms to adjust to potential damage, to take advantage of opportunities, or to respond to consequences (IPCC 2014). Alongside the steps the City and partner agencies have already taken protect the City from existing climate-related hazards, it is important to recognize the role community organizations and informal social networks can play in building adaptive capacity to the impacts of climate change.

SOCIAL NETWORKS AND SOCIAL COHESION
Aside from resources provided by the City or other agencies to help mitigate the impacts on residents and businesses during these events, social cohesion can play an important role in helping protect residents, particularly vulnerable populations, during climate-related disasters. Social cohesion, generally understood as the extent of connectedness and solidarity among groups in society or community, is one of the strongest indicators of resilience during disaster events as well as in post-disaster recovery efforts (Townshend et al. 2015). Important indicators of social cohesion, from the this research include:
 Belonging versus isolation, which means shared values, identity, feelings of commitment;  Inclusion versus exclusion, which concerns equal opportunities of access;  Participation versus non-involvement;
 Recognition versus rejection, which addresses the issue of respecting and tolerating differences in a pluralist society; and,
 Legitimacy versus illegitimacy (Jenson 1998).

An important component in remaining resilient to the impacts of climate change and climate-related disasters is the post-disaster recovery period. As noted in research on the topic, a focus not only of the physical rehabilitation of the built environment but on the addressing the emotional and mental health impacts of disasters is needed to ensure a successful community recovery during the post-disaster period. The emotional and mental health impacts of disasters can be addressed though various types of social cohesion including social and support networks (including access to social support in times of need), social participation (as the obverse of social isolation and being cut off from relationships providing friendship and company), and community engagement (including volunteering which draws people together to work for the benefit of others) (Townshend et al. 2015). While measuring the degree of social cohesion present in the City is not possible at this point, this subject is discussed here to emphasize the importance of social cohesion in increasing community resilience to the impacts of the climate change. Social cohesion here is highlighted as important component of community-based adaptative capacity and is discussed, as appropriate, in the discussions on specific climate
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Sources: City of San Luis Obispo in 2021
Figure 7 Location and Relative Density of Homeless Encampments in the City of San Luis Obispo DRAFT

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RESILIENT SLO COMMUNITY PRIORITIES SURVEY
The effects of climate change are already being felt by community members. In an effort to gather input on overall community priorities regarding climate-related hazards, concerns related to climate change impacts, experience with past hazard events and response efforts, and priorities for local action, a community priorities survey was developed and provided to community residents. The survey, consisting of 19 questions, was open from August 31, 2020 – October 11, 2020 and had 328 responses. Highlights from the survey results have been included in this Report to help better understand the community’s priorities regarding climate-related hazards and how the residents may already be affected climate-related hazards. The survey results are also included in the discussion on specific climate-related hazards.

As part of the survey, participants were asked what climate-related impact they were most concerned about. Figure 8 illustrates the responses to this question by age group. As shown in Figure 8, respondents were most concerned about wildfires and associated poor air quality events. Leading up to and during the survey response period, the City experienced poor air quality from several wildfires in the surrounding region, which may have influenced survey results. The large majority of respondents were also concerned about drought, increasing temperatures, and heat wave events and much less concerned about flooding and sea level rise. Survey results for this question also highlight that respondents in the 18-24 year old age cohort were the most concerned about almost all climate issues. To explore the full results of the community priorities survey, please refer to Baseline Conditions Report Sources: Resilient SLO Community Priorities Survey
Figure 8 City Resident’s Climate Concern by Age

COMMUNITY-BASED ORGANIZATIONS
Community-based organizations are generally understood as public or private nonprofit organizations that represent one or more segments of a community and/or provide educational or other community services to individuals or specific segments of the population. Climate-related hazards can also affect the ability of community-based organizations to operate and provide services to the communities they serve. Community-based organizations also play an important role in providing a wide variety of services to any community both during disaster and postdisaster recovery periods as well as during non-disaster periods (Tyler and Moench 2012). In many cases, communitybased organizations provide services to a communities most vulnerable population and as a result are the institutions most in touch with the day-to-day needs and concerns of these populations during both disaster and non-disaster periods (Murray and Poland 2020). There is a comprehensive network of organizations in the city and the County that 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Drought and
Decreased
Water Supply
Flooding and
Storm Damage
Hotter
Temperatures
and Heat
Waves
Sea Level Rise Wildfires Wildfire Smoke
Perecnt of Respondents
Climate Impact

CLIMATE CONCERN BY AGE
18-24
25-34
35-44
45-54
55-64
Above 65
Total Responses = 328
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provide a wide variety of services to SLO community residents and visitors. In June 2020, a brief survey was sent out to community-based organizations in the City to better understand how these organization’s operations were being affected by climate-related hazards and what responses were being taken to better prepare for the impacts of climate change. A total of eight community organizations responded to the survey. Figure 9 includes the results from two key questions in the survey, highlighting which climate-hazards community-based organizations have been affected by and which hazards they are concerned will affect their operations. The survey also asked what actions are being taken by the organizations to better prepare for climate changes. These results will be incorporated in the resilience strategy development process of the Resilient SLO project.

Figure 9 Climate -Related Hazard Impacts on Community Organizations in the City of San Luis Obispo

2.3 TEMPERATURE AND EXTREME HEAT ANALYSIS
This section discusses future increases in temperature and extreme heat in the City and analyzes how these changes are likely to impact the City and its population as well as highlighting what capacity the City and partner agencies already have in place to address future heat-related impacts.

2.3.1 Future Exposure to Temperature Increases and Extreme Heat The City is characterized by a Mediterranean climate. While the City is generally considered to have a mild climate, historically unseasonably warm periods and cold spells have been observed. According to Cal-Adapt, during the historic period (1961–1990), the annual average maximum temperature in the City was 71.1°F and the annual average minimum temperature was 43.7°F (CEC 2019a). The annual maximum and minimum daily temperatures are calculated by averaging daily values of maximum and minimum temperatures for the full year, which is then averaged over a thirty-year time-period to account for year-to-year variability.

Although the City has not historically experienced many extreme heat conditions, the City is likely to experience increased sensitivity to extreme temperatures because residents are not acclimatized to or prepared for extreme heat conditions, even if increases are relatively mild compared to other parts of the state. Extreme heat events are described in this section in terms of their intensity (i.e., average maximum temperature), frequency (i.e., how often they occur), time of year in which they occur, and duration (total number of consecutive extreme heat days). Figure 10 includes the average annual maximum and minimum temperatures for the City from 1926 through 2018. 0 2
4 6
8 Wildfire and associated
impacts
Increased Temperatures
and Extreme Heat
Large Storm Events and
Flooding
Long-Term Drought None of these
Number of Responses
Climate Hazard

HAZARD IMPACTS ON SLO COMMUNITY

ORGANIZATIONS
Which of the following climate change impacts are you concerned about affecting your organization and/or the populations you serve?
Which of the above-mentioned climate-related hazards has your organization been personally affected by in the past 1-3 years?
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Sources: Cal Poly 2020
Figure 10 Average Annual Maximum and Minimum Temperatures in the City (1926-2018)

AVERAGE TEMPERATURE
As shown in Table 9, both annual maximum and minimum are projected to increase throughout the 21st century. The average annual maximum temperature in the City is projected to increase to 71.6°F in the near-term and 73.1°F in the midterm under the high emissions scenario. The average annual maximum temperature is projected to increase to

73.1°F and 75.6°F in the late-century period under the medium and high emissions scenarios, respectively. The average annual minimum temperature in the City is projected to increase to 48.7°F in the near-term and 49.7°F in the midterm under the high emissions scenario, and the late-century average annual minimum temperature is projected to increase to 50.1°F and 52.7°F under the medium and high emissions scenarios, respectively (CEC 2019a). Increased temperatures in the City will influence secondary climate effects, including extreme heat events, wildfire, and drought.

Table 9 Changes in Average Annual Temperature in City of San Luis Obispo Geography Average Annual
Temperature
Historic Average
Annual Temperature
(1961-1990)
Near-Term
(2021-2050)
Midterm
(2035-2064)
Late-Century (2070-2099)
Medium
Emissions
High
Emissions
City of San Luis
Obispo
Maximum Temperature (°F) 68.4 71.6 73.1 73.1 75.6
Minimum Temperature (°F) 45.7 48.7 49.7 50.1 52.7
San Luis Obispo
County
Maximum Temperature (°F) 69.8 72.9 74.3 74.7 77.3
Minimum Temperature (°F) 42.2 45.4 46.6 46.9 49.8
Notes: °F = degrees Fahrenheit; RCP = Representative Concentration Pathway.

Source: CEC 2019a
Figure 11 illustrates the projected change in average annual maximum temperature in the city and in San Luis Obispo County (County) in the near-term and midterm periods under the high emissions scenario and average annual maximum temperature in the late-century period under both emissions scenarios. As shown in the Figure 11, the average annual maximum temperature is expected to rise through the late-century period under both emissions scenarios. As shown in Table 9, the County compared to the city, has had slightly higher maximum and minimum temperatures historically with this trend continuing under both emissions scenarios as temperatures continue to rise in both the city and the County. This difference is also reflected in Figure 11, which shows the City experiencing smaller increases in annual average maximum temperatures compared to northern and eastern portions of the County.

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Sources: Data downloaded from City of San Luis Obispo in 2020 and County of San Luis Obispo in 2020 and downloaded from Cal-Adapt in 2021 Figure 11 Changes in Annual Average Temperature in San Luis Obispo County through 2099 DRAFT

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EXTREME HEAT EVENTS
The Cal-Adapt tool provides estimates of future instances of extreme heat events. Extreme heat events include extreme heat days and heat waves. Cal-Adapt defines an extreme heat day as a day when the daily maximum temperature exceeds the 98th historical percentile of daily maximum temperatures based on observed data from 1961–1990 between April and October. Heat wave events are characterized as periods of sustained extreme heat and are defined by Cal-Adapt as four or more consecutive extreme heat days.

The extreme heat threshold for the city is 89.6°F, meaning 98 percent of all recorded temperatures in this period were below 88.6°F. Historically (1961-1990), the city experienced an average of four extreme heat days per year. As a result of rising temperatures from climate change, the city is projected to experience up to 7 extreme heats days annually in the near-term and 10 extreme heat days annually in the midterm under the high emissions scenario. In the latecentury period, the city is projected to experience up to 10 extreme heat days annually under the medium emissions scenario and 18 extreme heat days annually under the high emissions scenario (CEC 2019b). As shown in Table 10, the number of extreme heat days is already increasing from historic averages and will continue to increase through the late-century under both emissions scenarios. The city is already beginning to experience increases in extreme heat with a new September record high temperature of 117°F being set on September 6th, 2020 (NOAA 2021).

Table 10 Changes in Extreme Heat Events in City of San Luis Obispo Annual Averages
Historic Annual
Averages (1961-1990)
Near-Term
(2021-2050)
Midterm
(2035-2064)
Late-Century (2070-2099)
Medium
Emissions High Emissions
Number of Extreme Heat Days 4 7 10 10 18
Number of Heat Waves 0.2 0.3 0.4 0.4 1.3
Number of Days in Longest Stretch of
Consecutive Extreme Heat Days 2.6 2.8 3 3.4 4.6
Notes: RCP = Representative Concentration Pathway; Extreme Heat Day = day with maximum temperature above 89.6°F; Heat Wave = four or more consecutive extreme heat days
Source: CEC 2019b
While heat waves have historically been infrequent in the City, with a historical average of less than one heat wave annually, climate change is expected to increase the frequency of heat waves. Under the high emissions scenario, the City is projected to still experience less than one heat waves per year in the near-term and in the midterm. In the long term, the City is projected to experience less than one heatwave per year under the medium emissions scenario and 1.3 heat waves per year under the high emissions scenarios.

The average number of days in the longest stretch of consecutive extreme heat days per year is also projected to increase. Historically, the longest stretch of consecutive extreme heat days lasted for an average duration of approximately two-and-a-half days. The longest stretch of consecutive extreme heat days is projected to increase only slightly in the near-term and 3 days in the midterm under the high emissions scenario. In the late century, the duration is projected to increase to an average of 3.4 days under the medium emissions scenario and 4.6 days under the high emissions scenario (CEC 2019b). The timing of extreme heat days is also projected to change over the 21st century with more extreme heat days and heat wave events occurring earlier in the year (April through May) and more severe events occurring in the historically hot months of September and October (CEC 2019b). The projected number of heat waves and number of days in the longest stretch of consecutive extreme heat days is shown in Table 10.

Extreme Heat Definitions
Extreme Heat Day = Day with
maximum temperature above

89.6°F
Heat Wave = Four or more
consecutive Extreme Heat Days
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2.3.2 Extreme Heat Sensitivities and Impact
This section discusses the City’s existing sensitivities to extreme heat and analyzes potential impacts to City with impacts discussed in the three general impact categories (e.g., Natural Systems, Built Environment, Community Resilience).

EXTREME HEAT AND NATURAL SYSTEMS
Open Space and Ecosystem Functions
Increases in annual average maximum and minimum
temperatures are likely to alter suitable habitat for specific flora and fauna in the City, particularly in the City’s recreation and open space areas. In general, plant species in the Central Coast mountain ranges in or near the city will shift upslope to track warming temperatures while, in the lowlands, species will move northward over the 21st century. The City’s designated open space areas are comprised of a of a mixture of vegetation types including oak woodland, grassland, coastal sage scrub, and chaparral. Changes in annual average temperatures as well as long-term drought periods are projected to place increased pressure on these vegetation types. Invasive species have become more common in coastal sage scrub communities and compete with native coastal sage scrub species including commercial cultivars of the Monterey Pine (Pinus radiata) from New Zealand. However, it is unclear what effect climate change will have on invasive species in these open space areas (OPR et al. 2018b).

Many of the open spaces in and around the city also include inland grasslands. Historically, the duration and intensity of annual droughts in California varies substantially with elevation, latitude, distance to coast, and local soil characteristics. However, it is projected that most grassland species should be adaptive to tolerate climate extremes and variability (OPR et al. 2018b). As noted in the Central Coast Region Report, future changes in precipitation and drought will impact grasslands and wildflowers on the Central Coast and will be dependent on 1) the proximity to coast, 2) the relative proportion of native to exotic, and perennial to annual species.

Currently, the city has an extensive urban tree canopy with approximately 20,000 public trees on designated public property within the city limits. The City’s tree canopy provides key benefits to residents and business owners including shading, traffic calming, beautification, and carbon sequestration. However, due to shifts in annual average minimum and maximum temperatures in the future, the urban tree canopy may be threatened, with some tree species no longer suitable given future minimum and maximum temperature thresholds. Research indicates that increases in temperature result in decreased photosynthesis and tree growth, and subsequently less carbon sequestration potential, as well as elevated incidence of pests (Meineke et al. 2016). Research on the impact of climate change on street trees in 16 California cities indicates that certain tree species that may be less suitable under future climate conditions may be more resilient when they are part of urban tree network. This is because urban tree networks are managed by staff which typically includes irrigation and pest management (McBride and Laćan 2018), two important factors that affect the suitability of various tree species under future climate conditions. The combined urban heat island effect as well as increase in temperatures due to climate change will also place increased heat stress on the City’s urban tree canopy (McBride and Laćan 2018).

Invasive Species
As temperatures have increased over the past decade or more, observations have shown that invasive species have become more common in coastal sage scrub communities and compete with native coastal sage scrub species with the potential for coastal sage scrub habitats to convert to grasslands after fires, grazing, or nitrogen deposition. However, as noted in a recent study, while climate change is projected to affect coastal sage scrub communities, anthropogenic land use changes are likely to be
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a stronger indicator of effects on this habitat (Riordan and Rundel 2014).

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In terms of forests and tree species in and surrounding the City, climate change’s impacts on physical conditions in Central Coast forests will interact with biotic factors such as insect and disease outbreaks alongside changes in temperature and precipitation. The increasing presence of non-native species in the City’s riparian areas also creates competing demand for water resources alongside native populations of plant species. For the last several decades, Sudden Oak Death has affected coast live oak, canyon live oak, California black oak, Shreve oak, and the closely related tan oak. During wet weather, spores of the disease of (Phytophthora ramorum) are produced on infected leaves, which can be dispersed by wind or via transported soil transported by humans (e.g., hikers, bikes) to infect new hosts. Climate models suggest broad scale movement Sudden Oak Death into California’s North Coast by 2030, but less toward the southern portions (e.g., San Barbara County and San Luis Obispo County) of the Central Coast because of drier conditions there (Meentenmeyer et al. 2011).

Agriculture
Agricultural production is a prominent industry in the County of San Luis Obispo, including a thriving wine industry.

The City also includes some agricultural land uses most notably the San Luis Ranch and the City Farm, a communitybased urban farm hub, both located in the southern portions of the city west of US 101. The agricultural industry is highly sensitive to climate impacts including specific climate variables such as amounts, forms, and distribution of precipitation and changes in temperatures. Decrease in water availability due to long-term drought can affect crop yields and areas suitable for growing (Tanaka et al. 2015).

Increases in temperature, along with the frequency of extreme heat events and heat waves, has the potential to affect livestock operations in the County. Higher temperatures will lead to increased rates of evaporation of surface waters and evapotranspiration in plants, resulting in decreased moisture content of soils. These effects will lead to increased demand for irrigation to water crops. Warmer nighttime temperatures will reduce or eliminate the required number of “chill hours” that certain crops (e.g., fruit trees) need to bud (Union of Concerned Scientists n.d.). Strawberry production accounts for approximately 26 percent of total crop value in the County (County of San Luis Obispo 2018). It is projected that increases in temperatures caused by climate change could decrease yields of California strawberries by about 10 percent by 2050 and up to 43 percent between 2070 and 2099 (USDA 2016). Crop loss of this magnitude would result in significant loss of tax revenue to the County and result in impacts to employment opportunities for agricultural workers.

Additionally, changes in temperatures will alter the range of crop-damaging pests and microbial diseases, which could increase the susceptibility of certain crops to predation, increased spoilage, reduced nutritional content, and other damage. Livestock operations, which accounts for approximately 3 percent of total crop value in the County, could also be subject to heat stress, which can result in reduced livestock pregnancy rates, increased length of time needed to meet market weight, and reduced milk production (CNRA 2014:24).

Total yields for wine grapes may be reduced due to warmer winters in the future. Changes in temperature can also affect plant diseases, insects, and invasive weeds (Pathak et al. 2018). Because the City relies heavily on tourism including wine and vineyard-based tourism, impacts on agriculture and the wine industry due to climate change in the County could have negative economic impacts for the City and businesses. There are over 250 wineries throughout Paso Robles, Edna Valley, and other areas of the County that are national and international tourist destinations. The grape and wine industry has a large influence on agricultural production in the County. Grapes alone accounted for approximately 27 percent of all crop value in 2018, while the County produced one billion dollars in total crop value, demonstrating the significance of agriculture in supporting the County’s economy (County of San Luis Obispo 2018).

Key Findings and Policy Considerations
 Changes in temperature and extreme heat are likely to have negative impacts on the City’s tree canopy with some tree species no longer suitable for future minimum and maximum temperatures. Any future policies focused on improving the City’s tree canopy or green spaces to mitigate the urban heat island effect should carefully consider what plant and tree species will be suitable for future climate conditions.  Climate change is projected in invasive species in the City’s open spaces, affecting coastal sage scrub habitats as well as the City’s oak species from Sudden Oak Death.

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 Regional impacts on the agriculture and viticulture industries from shifting temperatures have the potential impact the City via decreases in wine and vineyard-based tourism, with the City relying heavily on revenue and employment opportunities in these industries. Resilience strategies focused on economic impacts should consider potential impacts on viticulture vineyard-based tourism and potential diversification of the City’s tax revenue sources and employment industries.

EXTREME HEAT AND THE BUILT

ENVIRONMENT
Urban Heat Island
Although the city’s Mediterranean climate includes high temperatures during summer and fall months, the city’s urban land use patterns can intensify periods of extreme heat through the “urban heat island” effect. The urban heat island effect is generally understood as the phenomenon of urban areas being significantly warmer than surrounding rural areas because of human activity and land use patterns in the built environment. Several factors contribute to the urban heat island effect, including land use patterns; the presence of large-paved areas (e.g., roads and parking lots); traffic from highvolume roadways (Zhu et al. 2017), impervious surfaces (e.g., roofs). Conversely, the presence of vegetation and trees in urban environments increases evapotranspiration in which water is released form plants in its gas vapor form and has a cooling effect on the surrounding air.

SLOCOG developed a regional definition for disadvantaged communities. Disadvantaged communities are disproportionately burdened areas that are economically distressed and/ or historically underrepresented as a part of the local government process. SLOCOG examined 13 variables, such as racial and ethnic minority, disability status, language proficiency, renter affordability, and household income. Many of these indicators also result in increased susceptibility to extreme heat impacts. To show how the urban heat island effect may further exacerbate projected heat impacts on the city, including vulnerable populations, Figure 12 identifies SLOCOG identified disadvantaged community areas, as well as the locations of critical facilities for vulnerable populations.

As shown in Figure 12, areas in the city with an increased concentration of commercial and industrial land uses have above-average surface temperatures. Notable urban heat island hotspots in the city include:
 the Service and Manufacturing, Office, and Business Park land uses near Tank Farm Road and South Higuera Street  the Neighborhood Commercial land uses near Broad Street and Tank Farm Road  some Commercial land uses along the northern portions of Monterey Street in downtown San Luis Obispo (SLO) Notably, the urban heat island hotspot along South Higuera Street is directly adjacent to residential land use to the east of South Higuera Street and north of Prado Road likely resulting in disproportionate impacts on these residential areas including increased energy demand for cooling.

Additionally, as shown in Figure 12, southern portions of the city include far less tree cover than areas near the downtown and the Laguna Lake area to the west of US 101, which is likely contributing to urban heat island hotspots in these areas. This include the Margarita Avenue Neighborhood (Census Tract 111.03) and the West of South Higuera Neighborhood (Census Tract 115.01) which have four and five percent tree cover, respectively, which is lower than many other parts of the City. Southern portions of the city including areas adjacent to southern portions of Broad Street and Tank Farm Road include newer residential and commercial developments which include younger trees and vegetation. This may reduce potential urban heat island effects as vegetation and the tree canopy increase in these areas in the future.

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Source: Data received and downloaded from City of San Luis Obispo and the Trust for Public Land.

Figure 12 Urban
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Heat Island Effect and Tree Cover in the City

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Buildings and Energy Use
Changes in annual average temperature and extreme heat events are likely to effect buildings primarily through changes in energy use as well as disproportionate impacts on individuals residing in units that do not have air conditioning. Cal-Adapt provides data on the shifts in Cooling Degree Days and Heating Degree Days, which are measurements used to assess the energy demand needed for cooling and heating buildings in different climate zones throughout California. A degree day does not equate to a single day of the year but rather compares the mean (the average of the high and low) outdoor temperatures recorded for a location to a standard temperature (i.e., 65°F).

For example, if the average temperature for a day is 80°F, the day has 15 Cooling Degree Days (80 – 65 = 15). Degree days are used in the State’s Title 24 Building Energy Efficiency Standards to help design the energy demand needed for heating and cooling in the various climate zones throughout the state. To illustrate how climate change is likely to affect energy demand for heating and cooling in the future, Table 11 includes the relative shift in Cooling Degree Days and Heating Degree Days in the city through 2099.

Table 11 Changes in building energy use through 2099
Impact Impact Type
Percent Change in Energy Demand for Heating and Cooling Near-Term (2021- Threshold Source
2050)
Midterm (2035-
2064)
Late-Century (2070-2099)
Low Emissions High Emissions
Building Energy Use
Cooling Degree
Days 66% 77% 80% 89% CEC 2019c
Heating Degree
Days -43% -68% -82% -161% CEC 2019c
Note: NA = not available.

Source: CEC 2019c
As shown in Table 11, in the near-term period, Cooling Degree Days in the City will increase by 66 percent while Heating Degree Days will decrease by 43 percent compared to historic averages. By the midterm period, Cooling Degree Days in the City will increase by 77 percent while Heating Degree Days will decrease by 68 percent compared to historic averages. In the late-century period under the medium emissions scenario, Cooling Degree Days will increase by 80 percent while Heating Degree Days will decrease by 82 percent. Under a high emissions scenario in the late-century period, Cooling Degree Days will increase by 89 percent while Heating Degree Days will decrease by 161 percent.

Changes in Cooling Degree Days will have implications for energy demand in residential and nonresidential buildings in the City with a higher energy demand for cooling and a decrease in energy demand for heating, in general. In general, for buildings in the City, increases in Cooling Degree Days will result in increased electricity demand for cooling and place increased demand on the electricity grid, particularly during extreme heat days and heat wave events which is projected to increase peak electricity demand for utilities. Currently, during extreme heat days and heat wave events, electricity utilities and the State’s grid operator, California Independent System Operator, initiate “Flex Alerts”, requesting customers to conserve energy during certain times of the day to reduce stress on the electricity grid (KSBY Santa Barbara-San Luis Obispo 2021). Some initial research that models future changes in peak load for utilities in California during extreme heat events has demonstrated that peak loads are substantially more sensitive to temperature anomalies, indicating warm-anomalous temperatures (e.g., extreme heat days and heat waves) will have a disproportionate impact on higher-intensity electricity consumption (Kumar et al. 2020). The research also indicates that disregarding the asymmetry in temperature response of electricity demand will lead to underestimating the climate-sensitive portion of the upper extremes of demand for electricity utilities in California, for short-term (2021-2040) and long-term (2081-2099) time periods included in the study.

As noted above, the urban heat island effect and hotspots in the City are likely to experience disproportionate increases in ambient air temperature during extreme heat days and heat wave events, further increasing electricity demand for cooling for homes with air conditioning
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for homes without air conditioning. As noted in the City’s recent Housing Element update, approximately 79 percent of the City’s housing stock was built before 1989 (City of San Luis Obispo 2020a). These older and, in general, less energy efficient homes are more susceptible to increases in energy demand for heating and cooling.

Key Findings and Policy Considerations
 The Margarita Avenue Neighborhood (Census Tract 111.03) includes population characteristics that make this area particularly vulnerable to extreme heat and is located in an area of the City with increased urban heat island severity. Resilience strategies that mitigate impacts of the urban heat island effect should focus on supporting this area of the City.
 Shifts in temperature and extreme heat will result in changes in energy demand for cooling in the City, with increased demand in areas experiencing more severe urban heat island hotspots. As the City implements it’s recently adopted Climate Action Plan and as well as the Resilient SLO strategies, solutions that both reduce GHG emissions and help the City adapt to impacts of climate change should be prioritized.  Older and, in general, less energy efficient homes are more susceptible to increases in energy demand for heating and cooling. Only 34 percent of homes in San Luis Obispo County have air conditioning with likely similar percentages in the City, making the City and it’s building stock particularly ill-equipped to projected increases in heat wave events.
 Extreme heat days and heat waves will have a disproportionate impact on electricity demand, with higher electricity demand projected for these events in the future. These projections place an increased urgency on electricity utilities to plan for higher electricity demand during these events in future.

EXTREME HEAT AND COMMUNITY RESILIENCE
Heat-Sensitive Populations
As discussed in Section 2.2., over the age of 65, infants and children, individuals with chronic health conditions (e.g., cardiovascular disease, asthma), low-income populations, athletes training outdoors, and outdoor workers are particularly vulnerable to climate-related hazards including extreme heat (CDC 2019).

Increased temperatures have been reported to cause heat stroke, heat exhaustion, heat syncope, and heat cramps, with certain vulnerable populations at increased probability of experiencing these effects (Kovats and Hajat 2008). Homeless populations often have higher rates of chronic disease because of extreme poverty, delays in seeking care, nonadherence to therapy, substance abuse, cognitive impairment, and other factors, placing them at increased risk during extreme heat events. Additionally, preexisting psychiatric illness can triple the risk of death for homeless populations during extreme heat events (Ramin and Svoboda 2009). Extreme heat can also worsen air quality, quickening the production of ozone in areas with increased concentrations of ozone precursors (i.e., oxides of nitrogen and reactive organic gases) (Knowlton et al. 2004). As shown in Figure 13 there is significant overlap between areas of moderate to severe urban heat island effect and areas with a higher share of older adults and youth under 5 years of age. The California Communities Environmental Health Screening Tool (CalEnviroScreen 4.0) includes an asthma prevalence indicator that measures the rate of emergency department visits for asthma. Although asthma rates in the City are low compared to statewide levels, there are areas of the City with relatively high asthma prevalence compared to local levels. Exposure to extreme heat has been shown to increase the risk of hospitalization for those with asthma (Dahl et al. 2019). As shown in Figure 14, the southern part of the City includes areas of more severe urban heat island effect and higher asthma prevalence. As noted in Section 2.2.2., the Margarita Avenue Neighborhood (Census Tract 111.03) and the West of South Higuera neighborhood (Census Tract 115.01) both include population characteristics that make these areas particularly vulnerable to extreme heat including higher percentages of elderly and disabled residents in these areas as well 50 percent of residents earning less than 200 percent of the federal poverty level in the Margarita Avenue Neighborhood.

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Sources: Data received from SLOCOG in 2021, downloaded from The Trust for Public Lands in 2020, City of San Luis Obispo in 2020, County of San Luis Obispo in 2020
Figure 13 Youth and Elderly Populations and
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Urban Heat Island Severity in the City

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Sources: Data downloaded from OEHHA in 2021, downloaded from The Trust for Public Lands in 2020, City of San Luis Obispo in 2020, County of San Luis Obispo in 2020 and received from CBEC Engineering in 2020 Figure 14 Asthma Rate Prevalence and
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Urban Heat Island Severity in the City

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Public Health and Extreme Heat
For this analysis, the California Heat Assessment Tool (CHAT) was used to identify how Heat Health Events would increase in the future. A Heat Health Event, for the purposes of the tool, is defined as any event that results in negative public health impacts, regardless of the absolute temperature. The tool includes unique Heat Health Events threshold for locations throughout the state, specific to the climate and the historical sensitivity of people in that area to past extreme heat events. Heat Health Events are defined by a set of meteorological conditions over several days that have been associated with significant negative public health impacts (i.e., rate of visits to local emergency rooms) in a specific location. The defined temperature threshold for the City in the CHAT tool is days when maximum temperatures reach 92.6°F and maximum humidity reaches 50.5 percent. Specifically, the tool focuses on emergency room visits for individuals under four and above 65 as well as all non-white individuals, to define a vulnerable population cohort. For this analysis, the CHAT tool and the projected increase in Heat Health Events in the City for the general populations and vulnerable populations, as defined by the tool, are used. For more information on the tool and methodology used to identify Heat Health Events, please visit the CHAT Tool website (cal-heat.org). Table 12 includes increases in Heat Health Events for the general population and vulnerable populations in the City through 2099.

Table 12 Heat Health Events through 2099
Impact Impact Type Population Historic
(1961-1990)
Near-Term
(2021-2050)
Midterm
(2035-2064)
Late-Century (2070-2099)
Threshold Source Low
Emissions
High
Emissions
Building
Energy Use
Heat Health
Events (HHE) General Population NA 1.3 1.4 1.75 5.4 CEC 2018 Heat Health
Events (HHE)
Vulnerable
Populations NA 8.23 10 11.2 12 CEC 2018
Note: NA = not available; CHAT = California Heat Assessment Tool.

Source: CEC 2018
As shown in Table 12, during the near-term period, the City’s general population will experience approximately 1.3 Heat Health Events while vulnerable populations to extreme heat will experience 8.23 Heat Health Events per year resulting in projected increases in demand for emergency services and hospital room visits. By the midterm period, the City’s general population will experience approximately 1.4 Heat Health Events per year while vulnerable populations will experience 10 Heat Health Events per year. In the midterm period under the medium emissions scenario, the general population will experience approximately 1.75 Heat Health Events per year while vulnerable populations will experience 11.2 Heat Health Events per year. Under the high emissions scenario for the late-century period, the City’s general population will experience a large increase to approximately 5.4 Heat Health Events per year while vulnerable populations to extreme heat will experience 12 Heat Health Events per year. As shown in Table 12, Heat Health Events for both the general population and vulnerable populations will continue to increase through the late-century period. For the general population, by the late-century period, Heat Health events will increase between 33 percent (low emissions scenario) and 315 percent (high emissions scenario). For vulnerable populations at increased risk from heat-related impacts, by the late-century period, Heat Health events will increase between 36 percent (low emissions scenario) and 46 percent (high emissions scenario). This analysis demonstrates a general increase in Heat Health Events throughout the century with a more pronounced impact on vulnerable populations who are at increased risk during Heat Health Events.

Environmental Justice and Extreme Heat
Alongside populations with health sensitivities, residents with specific sociodemographic characteristics are at increased sensitivity to extreme heat events (CDC 2019). Research has found that low-income residents spend a larger proportion of their income on utilities, including electricity use for cooling, with these residents being disproportionately affected during extreme heat events (Voelkel et al. 2018). Additionally, research has found that low-income neighborh
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oods can often have less tree coverage and park space, further contributing to the

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disproportionate impact on low-income residents (Zhu and Zhang 2008). Additionally, decreased access to transportation services can further increase exposure and health risks from extreme heat events for the unhoused community (Ramin and Svoboda 2009). Unhoused individuals are also at increased risk from extreme heat events with, generally, less access to places to cool off and healthcare resources during these events. Figure 15 shows the location of low-income areas in the City, based on the San Luis Obispo Council of Government’s (SLOCOG) regional definition of low-income. The map shows urban heat island hotspots and areas where average income level is less than 80 percent of the region’s average median income. Unhoused individuals are also at increased risk from extreme heat events with, generally, less access to places to cool off and healthcare resources during these events.

Additionally, decreased access to transportation services can further increase exposure and health risks from extreme heat events for the unhoused community (Ramin and Svoboda 2009).

The Margarita Avenue Neighborhood (Census Tract 111.03) is an area of the city with a particularly vulnerable population in regard to extreme heat. This area includes a high percentage of elderly and disabled residents, a high percentage of residents experiencing linguistic isolation, and 50 percent of residents earning less than 200 percent of the federal poverty level. This census tract also is located in a portion of the City that experiences a more intense severity of the urban heat island effect, resulting in potentially disproportionate impacts on this population during extreme heat events. The West of South Higuera neighborhood (Census Tract 115.01) also stands out as a particularly vulnerable to extreme heat, with the area also near urban heat island hotspots and includes a high percentage of elderly and disabled residents.

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Sources: Data received from SLOCOG in 2021, The Trust for Public Lands in 2020, City of San Luis Obispo in 2020, County of San Luis Obispo in 2020 and received from CBEC Engineering in 2020
Figure 15 Low
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Economic Systems and Extreme Heat
As discussed previously and shown in Table 9 and 10, the City will experience increases in average annual temperature and extreme heat days throughout the 21st century. However, these increases are, in general, less intense than increases many other parts of California, particularly in southern California and the San Joaquin Valley. Coastal communities in the County as well as the City already experience an influx of visitors during the summer months, many of them escaping the more extreme summer heat in the San Joaquin Valley. This phenomenon was even more pronounced during the recent heat waves in the summer of 2020, with the County and the City experiencing record maximum temperatures coupled with an influx of visitors escaping heat in other parts of the state (San Luis Obispo Tribune 2020). As shown in Figure 16, by approximately 2050, increases in average temperatures will be less severe relative to other parts of the state.

Increases in average temperature in June through July by 2050 under a high emissions scenario.

Source: Climate Impact Labs 2021
Figure 16 Relative Changes in Extreme Heat by 2050
Due to this milder change in temperature, the City and the County are likely to increasingly become a refuge for visitors and future permanent residents looking to escape more extreme climate impacts. This influx could have secondary impacts on the City including increase demand for services, increases in traffic congestion, and increases demand for housing, placing additional pressure on the City’s housing market and affordability issues. Given that the City is an attractive destination for tourism, coupled with the characteristics that could serve as a refuge for the impacts from climate change, these factors pose a unique issues with potential benefits and drawbacks that should be considered carefully.

Community Extreme Heat Concerns
As part of the community priority survey, when participants were asked to report on their level of concern for extreme heat, as shown in Figure 17, 87 percent of respondents indicated that they were “Somewhat” or “Very” concerned about the issue. Ninety percent of individuals indicated they had been “Somewhat” or “Very” impacted by extreme heat in the past 1-3 years. Additionally, individuals with a household income of less than $50,000 and individuals between the ages of 18 and 24 had the highest level of concern for extreme heat. Individuals who note their housing situation as “Renter” or “Other” indicate the highest l
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evel of concern for extreme heat (i.e., 79 percent versus 58 percent for homeowners).

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Sources: Resilient SLO Community Priorities Survey
Figure 17 City Resident’s Extreme Heat Concern and Impact Key Findings and Policy Considerations
 The Margarita Avenue Neighborhood (Census Tract 111.03) West of South Higuera neighborhood (Census Tract 115.01) is an area of the city with a particularly vulnerable population in regard to extreme heat, with a high percentage of elderly, disabled, or low-income residents. The West of South Higuera neighborhood (Census Tract 115.01) also includes a high percentage of elderly and disabled residents, making this area particularly vulnerable to extreme heat impact.
 Low-income residents are particularly vulnerable to extreme heat impacts due to a number of factors including a higher reliance on public transit (leaving these residents more exposed to extreme heat during transit use), a higher percentage of income being devoted toward utility bills, and a trend of lower income neighborhoods having less tree cover. Unhoused individuals are also at increased risk from extreme heat events with, generally, less access to places to cool off and healthcare resources during these events.  The City and the County, in general, have historically served as a destination for summer tourists to escape more extreme summer heat in the San Joaquin Valley and southern California. As extreme heat events continue to increase disproportionately in those areas of the state compared to less severe increases locally, the City may experience increases in this phenomenon placing increased demand on services, impacts on City infrastructure and resources, as well increased pressure on the housing shortage issue in the City from new permanent residents.
13%
18%
69%
9%
42%
48%
0%
10%
20%
30%
40%
50%
60%
70%
80%
Not at all Somewhat Very
Percent of Respondents
Level of Concern

EXTREME HEAT CONCERN & IMPACT
Which of the following climate change impacts are you concerned about [Extreme Heat]? Which of these hazards have you been personally affected by in the past 1-3 years in the City of San Luis Obispo [Extreme Heat]?
Total Responses = 328
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2.3.3 Adaptive Capacity for Temperature and Extreme Heat Events ADAPTIVE CAPACITY RATING: LOW
While the City has experienced periods of extreme heat historically, this climate-related hazard has not been a prominent issue for the City in the past. Because prolonged heat events have been rare in the City, both the City’s 2006 Local Hazard Mitigation Plan and the more recent Annex G of the County’s Multi-Jurisdictional Hazard Mitigation Plan do not discuss or evaluate extreme heat events in any detail. Specifically, the City’s portion of Annex G of the County’s Multi-Jurisdictional Hazard Mitigation Plan does not include any mitigation actions specific to extreme heat or protecting vulnerable populations from extreme heat. The City’s Emergency Operation Plan also does not include a specific discussion or protocols for addressing extreme heat events when they occur. The exclusion of extreme heat from these documents is likely because these events have not been an issue historically.

The City is currently working to implement its recently adopted Climate Action Plan which includes strategies for the electrification of new and existing buildings (Green Buildings 1.1 and 1.2 in City’s Climate Action Plan). As the City continues this work to electrify new and existing buildings, changes in electricity demand for cooling will remain an important consideration for the energy design of new buildings and existing building retrofits. Decreases in HDDs due increase in annual maximum and minimum temperatures as shown in Table 11, will result in decreased demand for heating fuels, which for buildings in the City is primarily natural gas. Decreases in energy demand for heating also has the potential to decrease the City’s overall GHG
emissions and help achieve the City’s GHG emissions
reduction targets.

As noted previously, 79 percent of the City’s housing stock was built before 1989, reducing the ability of these older and less energy efficient homes to adapt to changes in extreme heat. In the County as a whole which can serve as proxy for the City, only 34 percent of households include air
conditioning, placing these households at increased risk when extreme heat events do occur (CEC 2009). Retrofitting homes with central air conditioning or air conditioning units can be a major expense, especially for low-income
households, and may not be possible for City residents who are renting. Overall, because the City has not historically experienced many extreme heat conditions,, residents are not acclimatized to or prepared for extreme heat conditions, which makes the City particularly sensitive to extreme
temperatures.

For these reasons, the adaptive capacity ranking for increased temperatures and extreme heat is ranked as low.

Climate Action Plan and Resilient SLO
In 2020, the City adopt the Climate Action
Plan for Community Recovery which
establishes a community-wide goal of carbon
neutrality by 2035, adopts sector specific
goals, and provides foundational actions to
establish a trajectory towards achieving those
goals. The Resilient SLO project focuses on
developing strategies to make the City more
resilient to the impacts of climate change.

However, as the City implements the Climate
Action Plan and the Resilient SLO strategies,
it will be important to prioritize solutions that
both reduce GHG emissions and help the
City adapt to impacts of climate change.

Both reducing emissions and adapting to
climate change serve to create a more
resilient community.

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2.3.4 Vulnerability Summary
Overall, the City is projected to experience noticeable increases in annual average temperatures and extreme heat events. These changes will result in varying impacts on the City and its residents as discussed above. Based on the analysis of various impacts discussed in Section 3.2.2, the City’s potential impact scoring is Medium (2). Impacts that are unique to the City and should be given increased consideration during the adaptation strategy development process are discussed below.

Natural System Findings
 Changes in temperature and extreme heat are likely to have negative impacts on the City’s tree canopy with some tree species no longer suitable for future minimum and maximum temperatures. Any future policies focused on improving the City’s tree canopy or green spaces to mitigate the urban heat island effect should carefully consider what plant and tree species will be suitable for future climate conditions.  Climate change is projected in invasive species in the City’s open spaces, affecting coastal sage scrub habitats as well as the City’s oak species from Sudden Oak Death.
 Regional impacts on the agriculture and viticulture industries from shifting temperatures have the potential to impact the City via decreases in wine and vineyard-based tourism, with the City relying heavily on revenue and employment opportunities in these industries. Resilience strategies focused on economic impacts should consider potential impacts on viticulture vineyard-based tourism and potential diversification of the City’s tax revenue sources and employment industries.

Built Environment Findings
 The Margarita Avenue Neighborhood (Census Tract 111.03) includes population characteristics that make this area particularly vulnerable to extreme heat and is located in an area of the City with increased urban heat island severity. Resilience strategies that mitigate impacts of the urban heat island effect should focus on supporting this area of the City.
 Shifts in temperature and extreme heat will result in changes in energy demand for cooling in the City, with increased demand in areas experiencing more severe urban heat island hotspots. As the City implements it’s recently adopted Climate Action Plan and as well as the Resilient SLO strategies, solutions that both reduce GHG emissions and help the City adapt to impacts of climate change should be prioritized.  The City’s historically moderate climate has, in general, not required the City’s existing building stock to be designed or equipped with air conditioning. However, as average temperatures and extreme heat events increase in the future, residents are ill-equipped to prepare for these events. Additionally, increases in temperature and extreme heat will result in increased energy demand for cooling, which underscores the need to support distributed energy resources, customer sited energy storage, demand response, and grid/building connected appliances and vehicles.
 Extreme heat days and heat waves will have a disproportionate impact on electricity demand, with higher electricity demand projected for these events in the future. These projections place an increased urgency on electricity utilities to plan for higher electricity demand during these events in future.

Community Resilience Findings
 The Margarita Avenue Neighborhood (Census Tract 111.03) West of South Higuera neighborhood (Census Tract 115.01) is an area of the city with a particularly vulnerable population in regard to extreme heat, with a high percentage of elderly, disabled, or low-income residents. The West of South Higuera neighborhood (Census Tract 115.01) also includes a high percentage of elderly and disabled residents, making this area particularly vulnerable to extreme heat impact.
 Low-income residents are particularly vulnerable to extreme heat impacts due to a number of factors including a higher reliance on public transit (leaving these residents more exposed to extreme heat during transit use), a higher percentage of income being devoted toward utility bills, and a trend of lowe DRAFT
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having less tree cover. Unhoused individuals are also at increased risk from extreme heat events with, generally, less access to places to cool off and healthcare resources during these events.  The City and the County, in general, have historically served as a destination for summer tourists to escape more extreme summer heat in the San Joaquin Valley and southern California. As extreme heat events continue to increase disproportionately in those areas of the state compared to less severe increases locally, the City may experience increases in this phenomenon placing increased demand on services, impacts on City infrastructure and resources, as well increased pressure on the housing shortage issue in the City from new permanent residents.

Temperatures and Extreme Heat Vulnerability Score
Adaptive Capacity: Low (3)
Potential Impact: Medium (2)
Vulnerability Score: 4

2.4 LONG-TERM DROUGHT ANALYSIS
This section discusses future long-term drought scenarios for the City and analyzes how long-term drought could impact City and its population as well as highlighting what capacity the City and partner agencies already have in place to address future drought impacts.

2.4.1 Future Exposure to Long-Term Drought Scenarios
Long-term drought can have environmental, agricultural, health, economic, and social consequences. The County, along with larger areas of California, experiences periods of long-term drought that stress ecosystems and water supplies; and subsequently, impact agriculture, public health, and the economy. The City relies on regional water supplies with the four primary sources being Whale Rock Reservoir, Salinas Reservoir, Nacimiento Reservoir, and recycled water (City of San Luis Obispo 2019). Because the City relies on reservoirs in the County, outside the City limits, this analysis focuses on long-term drought scenario projections for the County as a whole.

While average annual precipitation in the County is projected to trend upward in future years, the key finding for this climate effect is that precipitation patterns are expected to become more volatile, with potentially less frequent but intense storms that produce above average amounts of precipitation. As discussed in more detail in Section 2.5, precipitation patterns in California oscillate between extremely dry and wet periods. Climate change is anticipated to exacerbate these seasonal extremes with dry periods becoming dryer and wet periods becoming wetter (OPR et al. 2018b:19). As a result, the frequency and severity of large storm events are anticipated to increase as well. These oscillations between extremely dry and extremely wet periods, which have occurred historically in the state, are anticipated to become more severe with rapid shifts from dry to wet periods known as “whiplash events” (Swain et al. 2016). With the increased severity of oscillation between wet and dry periods and precipitation occurring over more intense but shorter periods in the year, this will reduce opportunities for groundwater recharge which ideally occurs during prolonged wet periods allowing for soil infiltration, deeper percolation, and the resulting groundwater recharge. As discussed further in Section 2.4.2, while a unique long-term drought scenario would likely affect the City’s overall water supply management practices, there is the potential for there still to be above average wet years within a long-term drought, as shown in Figure 18. These above average wet years have the potential to replenish water supplies in the City’s reservoirs and help mitigate the impacts of long-term drought. Table 13 includes projections for average annual precipitation in the County through 2099 as well as rainfall projections for changes in the 5-year storm event, demonstrating the increased intensity of large storm events and wet years in the future.

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Table 13 Changes in Average Annual Precipitation and 5-Year Storm Event in San Luis Obispo County Average Annual Precipitation Historic Average Annual
Precipitation (1961-1990)
Near-Term
(2021-2050)
Midterm
(2035-2064)
Late-Century (2070-2099)
Medium
Emissions
High Emissions
Average Annual Precipitation (inches) 16.1 18.1 17.8 17.2 19.8 5-Year Storm Event (2-day rainfall) 7.9 7.9 8 8.2 9.8
Source: CEC 2019a
As shown in Table 13 above, under both the low and high emissions scenarios, the County is expected to experience slight overall increases in average annual precipitation in the late century. However, projections show the County will experience increased variability and volatility in precipitation events such as droughts. The County and state have a highly variable climate that is susceptible to prolonged periods of drought, and recent research suggests that extended drought occurrence (a “mega-drought”) could become more pervasive in future decades (OPR et al. 2018b).

Cal-Adapt uses data to model an extended drought scenario for all of California from 2051 to 2070 specifically using the HadGEM2-ES GCM model under a high emissions scenario. The extended drought scenario is based on the average annual precipitation over 20 years. As shown in Table 13, the County’s observed historical (1961-1990) average annual rainfall accumulation is 16.1 inches. Under the anticipated drought scenario between 2051 and 2070, the County’s average annual rainfall accumulation would decrease to 13.3 inches (CEC 2019a), resulting in an approximately 18 percent decrease in annual average rainfall over a 20-year period.

Source: Cal-Adapt 2021
Figure 18 Projected Drought Conditions between 2051 and 2070 for San Luis Obispo County DRAFT

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2.4.2 Drought Sensitivities and Impacts
This section discusses the City’s existing sensitivities to long-term drought and analyzes potential effects on the City, discussed in the three general impact categories (e.g., Natural Systems, Built Environment, Community Resilience).

DROUGHT AND NATURAL SYSTEMS
Open Space and Ecosystem Functions
The City’s designated open space areas include a mixture of vegetation types including oak woodland, grassland, coastal sage scrub, and chaparral that are anticipated to be impacted by changes in annual average temperatures, extreme heat, and long-term droughts (OPR et al. 2018b). Historically, the duration and intensity of droughts in California varies substantially with elevation, latitude, distance to coast, and local soil characteristics. Native perennial grasses tend to concentrate growth periods during wet winter months, adapting to the annual summer drought (Vaughn et al. 2011). Some native perennial grasses can survive prolonged droughts in a non-green state and then regenerate after it rains (Potter 2015). As a result, it is projected that most grassland species should be adaptive to tolerate climate extremes and variability (OPR et al. 2018b). The diversity of ecological communities along the California coast are linked to the summer marine layer of fog and low clouds, allow for adaptations. Chaparral shrubs, in general are more drought tolerant. Future changes in precipitation and drought will impact grasslands and wildflowers on the Central Coast and will be dependent on the proximity to the coast as well as the relative proportion of native to non-native, and perennial to annual species (OPR et al. 2018b).

In dryer years and drought periods, demographic rates for annual plants (e.g., survival, reproduction) are lower than in wetter years (Fox et al. 2006). As dry years and long-term droughts become more common in the future, population growth rates of annual plant species will become marginal, and populations are likely to become locally extinct. Foraging on these annuals, particularly by deer, rabbits, and woodrats reduces population growth even more than drought in some species, but not others (OPR et al. 2018b).

Deer browse (e.g., leaves, twigs, and buds of woody plants eaten by deer) reduces growth, reproduction, and survival in ceanothus (e.g., California Lilac). As the abundances of deer and other wildlife declined during the recent drought of 2011-2017, previously browsed shrubs grew and reproduced well and then responded rapidly to the two wet years since. These observations suggest that unless deer populations increase again between droughts, or in areas without much deer browse, ceanothus shrub are likely to grow rapidly, but will become vulnerable with further droughts projected under climate change (OPR et al. 2018b).

Key Findings and Policy Considerations
 The City’s designated open space areas include a mixture of vegetation types including oak woodland, grassland, coastal sage scrub, and chaparral that are anticipated to be impacted by changes in annual average temperatures, extreme heat, and long-term droughts (OPR et al. 2018b).  As dry years and long-term droughts become more common in the future, population growth rates of annual plant species will become mar
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ginal, and populations are likely to become locally extinct (OPR et al. 2018b).

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DROUGHT AND THE BUILT ENVIRONMENT
Water Supply
While increasingly frequent and prolonged droughts affect the City’s drinking water supply, the City’s built environment (e.g., buildings, roadways) will not experience direct physical impacts associated with this climate-related hazard. However, drought conditions and other climate-related effects will likely effect reservoirs, located outside the City boundaries, which provide water to the City. For the Central Coast, a 50-year projection for land uses from 2012 to 2062 suggest potential changes that could affect groundwater supplies including a large amount of grassland habitat loss over 50 years that will exacerbate challenges in preserving and recharging groundwater aquifers, as well as increased water demand due to urbanization and expansion of berries and vineyards (Wilson et al. 2016).

As shown in Figure 18, even during a future long-term drought scenario, there would be years with above average rainfall for one or even multi-year periods. However, these one or multi-year periods with above average rainfall may not be sufficient to restore reservoirs to normal water levels compared to non-drought periods. For example, during the statewide drought between approximately 2011 and 2016, water supplies on the Central Coast were severely affected with increases in reservoirs and groundwater levels varying significantly across the Central Coast region following the above average 2016-2017 winter rain season (OPR et al. 2018b). As noted in the City’s 2017 Water Resources Status Report, between January 2017 and June 2017 the water supply in the Salinas Reservoir went from 10 percent to 100 percent, the Whale Rock Reservoir went from 32 percent to 79, and the Nacimiento Reservoir shifted from 25 percent to 78 percent (City of San Luis Obispo 2021b). This dramatic shift from a multi-year drought between 2011 and 2015 drought followed by an above average wet year in the 2016-2017 winter rain season was characteristic of a whiplash event (Swain et al. 2018) and allowed the City to replenish its water supplies. However, these whiplash events may affect water supply management practices over the long-term, particularly as the swings from multi-year dry to wet periods become more prolonged and more severe (Persad et al. 2020).

As part of the City’s 2020 Urban Water Management Plans (UWMP), climate change modeling was conducted to determine future projections on the City’s safe annual yield. Safe annual yield is generally defined as a measurement used to determine the average replenishment rate of a water body or aquifer from natural and artificial recharge, which factors in evaporation, transpiration, and basin outflow into the replenishment rates. Safe annual yields are calculated as the quantity of water which can be withdrawn regularly and permanently without dangerous depletion of the storage reserve. Based on the climate modeling included in the 2020 UWMP, it was determined that, when accounting for future precipitation patterns due to climate change, the safe annual yield for Whale Rock and Salinas Reservoirs (two reservoirs included in the City’s water supply portfolio) could shift from a decrease of as much as 850-acre-feet per year (AFY) to an increase of as much as 160 AFY. However, these potential shifts are relatively small compared to the City’s overall safe annual yield of 10,130 acre-feet from the full water supply portfolio, with shifts from climate change accounting for an approximately 8 percent decrease to 2 percent increase in the City’s overall supply (City of San Luis Obispo 2021b).

Sediment Deposition
The buildup of sedimentation in reservoirs can reduce a reservoir’s available storage volume. As noted in the City’s 2020 Urban Water Management Plan (UWMP), the Whale Rock and Salinas Reservoirs, which provide water to City, are projected to experience an total loss of 500 acre-feet of water between 2010 to 2060 period (a rate of 10 acre-feet per year over 50 years). Intense, long-duration winter storm rainfall can result in the movement of large sediment quantities into reservoirs (OPR et al. 2018b). In the Central Coast region, annual sediment movement from individual watersheds varies by a factor of 500 or more between extreme dry and extreme wet years (Conaway et al., 2013; East et al., 2018). Landscape disturbances including wildfire, post-wildfire runoff, or landslides after wet winters, is projected to increase sediment yield from watersheds along the Central Coast (OPR et al. 2018b) and will reduce the amount of water-storage capacity in dammed Central Coast reservoirs (Smith et al. 2018). Changes in vegetation and fire regimes could also potentially add to the likelihood of increased sediment flux (Sankey et al., 2017). Sediment, including the nutrients and chemicals adsorbed in sediment, can result in
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decreased water quality and make water treatment more technically complex and more costly.

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Key Findings and Policy Considerations
 Dramatic shifts from multi-year dry periods to wet periods, similar to the 2011-2015 drought followed by an above average wet year in the 2016-2017, are known as whiplash events (Swain et al. 2018) and they are expected to become more severe in the future. These whiplash events may affect water supply management practices over the long-term, particularly as the swings from multi-year dry to wet periods become more prolonged and more severe, with an emphasis on increasing rainfall storage when it does occur during the wet periods (Persad et al. 2020).  Buildup of sedimentation that reduces a reservoir’s available volume already occurs in the City’s water storage system, with the City implementing programs and policies to address this storage loss over the long term. However, landscape disturbances including wildfire, post-wildfire runoff, or landslides after wet winters, is projected to increase sediment yield from watersheds along the Central Coast (OPR et al. 2018b), with the potential to further reduce the amount of water-storage capacity in dammed Central Coast reservoirs (Smith et al. 2018).  The City’s Safe Annual Yield analysis included in the 2020 UWMP modeled potential impacts on the City’s water supplying, finding that changes in precipitation could result in a decrease of as much as 850 AFY to an increase of as much as 160 AFY, accounting for an approximately 8 percent decrease to 2 percent increase in the City’s overall water supply (City of San Luis Obispo 2021b).

DROUGHT AND COMMUNITY RESILIENCE
Vector-borne and Infectious Disease
Increases in temperature and extreme heat events are
associated with increases in vector-borne and infectious disease transmission (OPR et a. 2018b). Based on recent research, summarized in the Central Coast Report, future longterm drought scenarios have the potential to increase the prevalence of certain vector-borne diseases present on in the central coast region. For example, long-term drought can affect the life cycles and extend the habitat range of native tick species that can harbor Lyme disease and other illnesses (OPR et a. 2018b). Cases of vector-borne disease, including Lyme disease, are projected to increase in the future due to climate change (Estrada-Pena, A., N. Ayllon, and J. de la Fuente 2012). However, in the Central Coast region, the spread of Lyme disease has likely been contained due to the area’s drier climate and differing vegetation (MacDonald, A.J. et al. 2017). A newly identified vector-borne disease, Pacific Coast tick fever (PCTP), has been identified (Padgett, K.A., et al. 2016). Although an emerging illness, a few of the human cases originated specifically in the Central Coast. PCTP has exhibited a summer trend so far. Therefore, increasing temperatures have the potential to extend PCTP’s transmittal season in the Central Coast.

A lack of soil moisture during long-term droughts can increase dust particle concentration, which can include harmful fungal spores and viruses, including coccidioidomycosis (valley fever) (OPR et a. 2018b). The California Department of Public Health (CDHP) has highlighted the Central Coast as a high-risk area for valley fever (OPR et a. 2018b). Valley fever is found in disturbed, dry soil particles that must be inhaled. Symptoms of Valley fever include chest pain, exhaustion, fever, coughing, joint and muscle pain, and difficulty breathing. Certain populations including pregnant women, the elderly, African, and Filipino Americans are particularly vulnerable to the severe cases of the disease (Brown et al. 2013). Santa Barbara and San Luis Obispo Counties, where the Valley fever fungus, C. immitis, is endemic, reported larger numbers of cases in 2017, with the CDPH reporting over 500 cases for these two counties (San Luis Obispo Tribune 2016).

Key Findings and Policy Considerations
 Increases in temperature and extreme heat events are associated with increases in vector-borne and infectious disease transmission, with future long-term drought scenarios potentially increasing the prevalence of certain vector-borne diseases present on in the central coast region DRAFT
including Lyme disease and Valley fever.

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2.4.3 Adaptive Capacity for Drought Impacts
ADAPTIVE CAPACITY RATING: HIGH
Utilities Department and Water Management
Short- and long-term droughts have historically been an issue for the City and the Central Coast region. As a result, the City already has a comprehensive set of initiatives and resources in place to address drought periods when they do occur. In 2021, the City adopted the 2020 UWMP which evaluates the current and projected water supplies through the year 2040. The UWMP was prepared in accordance with the Urban Water Management Planning Act, and accordingly, will be updated every 5 years and submitted to the California Department of Water Resources. Goals in the UWMP related to this this Report include the following:
 assess current and future water use trends in the community;  summarize the water supply and the water system;
 assess water supply reliability;
 document the water demand; and
 manage measures in place to balance supply and demand.

The 2020 UWMP includes a section specially on Water Resiliency Planning which highlights a set of strategies the City has taken to ensure long-term water resiliency and to mitigate the impacts from a long-term drought scenario. These include:
 a multi-source water supply;
 conservative water supply projections;
 water use efficiency;
 water recycling; and
 future groundwater recharge.

As noted in the 2020 UWMP, the City has a Reliability Reserve and a Secondary Water Supply which have been incorporated in water management planning and calculations to provide a buffer for future unforeseen or unpredictable long-term impacts to the City’s available water resources such as loss of yield from an existing water supply source and impacts due to climate change. The Reliability Reserve provides a twenty percent buffer beyond the City’s projected water demand at build out. As discussed in Section 2.4.2, the 2020 UWMP includes forecasted projections on the City’s safe annual yield which accounts for potential shifts in precipitation caused by climate change. The 2020 UWMP also includes key considerations on how climate change may affect water demand in years with less rainfall (City of San Luis Obispo 2021b).

In 2006, the City completed the Water Reuse Project, creating the first new source of water for the City since 1961.

The project included improvements to the City’s Water Resource Recovery Facility and an initial eight miles of distribution pipeline for use by City residents and businesses for landscape irrigation and other approved uses. In 2017, the City completed the Recycled Water Master Plan. The plan describes future opportunities for the City to consider potable reuse, presents a plan to serve recycled water to developing areas of the community for use as landscape irrigation, prioritizes opportunities to retrofit existing sites to offset potable water use, and explores use of recycled water outside the City limits during periods where much of the City’s recycled water supply goes underutilized. Chapter 7 of the plan includes a capital improvement plan for future expansion of the City’s recycled water distribution system, which is consistent with the City’s larger water supply management strategy to maintain multi-source water supply. The City’s current recycled water program can generate over 1,000 acre-feet of recycled water for approved uses, reducing water demand from the City’s other water supply sources. In 2020, 245 acre-feet of recycled water were delivered to the community (City of San Luis Obispo 2021b DRAFT
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As part of the 2020 UWMP, the City has also developed the 2020 Water Shortage Contingency Plan, which establishes the foundation for a staged response to worsening water shortage conditions that could occur due to drought, earthquake, infrastructure failure, or other emergencies. The 2020 Water Shortage Contingency Plan establishes the City’s water supplies for a normal year, single dry year (2013) and a multiple dry year scenario, identified as the years 2011 to 2015, with combined rainfall total for those five years being the lowest on record.

Alongside developing a water shortage assessment, the plan also includes a comprehensive water shortage response to temporarily augment supply and/or reduce water demand. This response would include voluntary reduction measures, mandatory reduction measures, water use prohibitions, and supplemental water supply options.

General Plan Water and Wastewater Management Element
The City’s General Plan Water and Wastewater Management Element, most recently updated in 2020, includes a comprehensive set of goals, policies, and programs manage the City’s water supply and includes measures to address the potential impacts of climate change on the City’s water supply. The updated Water and Wastewater Management Element coincides with the City’s efforts to incorporate climate change projections into the City’s safe annual yield assessment and water management practices. Goals in the element focus on the various components of successful water management including managing the City’s multi-source water supply, water supply accounting and water demand projections, water conservation practices, and the implementing the City’s recycled water program. The Water and Wastewater Element also includes a goal specifically for siltation management in the City’s reservoirs, noting the potential for the increasing intensity of rainfall events as well as post-wildfire runoff to increase siltation rates and reduce the overall storage capacity of the City’s reservoirs. Noting this potential threat, the Siltation portion of the element includes a set of policies and programs to proactively implement best management practices to reduce erosion and subsequent siltation consistent with other City watershed management goals.

Sustainable Groundwater Management Act and Groundwater Recharge The City, in coordination with the County and partner agencies, are increasing efforts to achieve sustainable groundwater management through requirements in the Sustainable Groundwater Management Act. The City and County, in coordination with local water purveyors including the Edna Valley Growers Mutual Company, Edna Ranch Mutual Water Company, Varian Ranch Mutual Water Company and Golden State Water Company, developed a Groundwater Sustainability Plan to sustainably manage groundwater resources in the San Luis Obispo Valley Groundwater Basin and prevent an unreasonable reduction of groundwater storage in the basin. The City’s portion of the San Luis Valley Groundwater Basin is currently estimated to have a 700 acre-foot per year surplus of groundwater.

This is largely because the City is not currently pumping groundwater. The City plans to resume groundwater pumping within the next five years to better balance surface water and groundwater use in order to mitigate climate change impacts.

Alongside development and implementation of the Groundwater Sustainability Plan, through implementation of the State mandated NPDES Stormwater Program and the Post Construction Requirements, new and re-developments are required to retain and infiltrate water that would have previously been piped off the property. This requirement helps to mitigate stormwater runoff and supports groundwater recharge in the San Luis Valley Groundwater Basin.

For these reasons, the adaptive capacity ranking for increased long-term drought is high.

2.4.4 Vulnerability Summary
Due to increases in annual average temperatures and extreme heat discussed in Section 3.2, as well as the increased likelihood of a long-term drought scenario, the City is vulnerable to impacts from drought caused by climate change.

These changes will result in varying impacts on the City and its residents as discussed above. Based on the analysis of various impacts discussed in Section 3.3.2, the City’s potential impact scoring is High (3). Impacts that are unique to the City and should be given increased consideration during the adaptation strategy development process are discussed below.

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Natural System Findings
 The City’s designated open space areas include a mixture of vegetation types including oak woodland, grassland, coastal sage scrub, and chaparral that are anticipated to be impacted by changes in annual average temperatures, extreme heat, and long-term droughts (OPR et al. 2018b).  As dry years and long-term droughts become more common in the future, population growth rates of annual plant species will become marginal, and populations are likely to become locally extinct.

Built Environment Findings
 Dramatic shifts from multi-year dry periods to wet periods, similar to the 2011-2015 drought followed by an above average wet year in the 2016-2017, are known as whiplash events (Swain et al. 2018) and they are expected to become more severe in the future. These whiplash events may affect water supply management practices over the long-term, particularly as the swings from multi-year dry to wet periods become more prolonged and more severe, with an emphasis on increasing rainfall storage when it does occur during the wet periods (Persad et al. 2020).  Buildup of sedimentation that reduces a reservoir’s available volume already occurs in the City’s water storage system, with the City implementing programs and policies to address this storage loss over the long term. However, landscape disturbances including wildfire, post-wildfire runoff, or landslides after wet winters, are projected to increase sediment yield from watersheds along the Central Coast (OPR et al. 2018b), with the potential to further reduce the amount of water-storage capacity in dammed Central Coast reservoirs (Smith et al. 2018).  The City’s 2020 UWMP modeled potential impacts on the City’s water supplying, finding that changes in precipitation could result in a decrease of as much as 850 AFY to an increase of as much as 160 AFY, accounting for an approximately 8 percent decrease to 2 percent increase in the City’s overall water supply (City of San Luis Obispo 2021b).
 With more rapid shifts from dry to wet periods known as “whiplash events,” precipitation will occur over shorter more intense periods. This shift has the potential to reduce groundwater recharge which ideally occurs during prolonged wet periods to allow for soil infiltration, deeper percolation, and more effective groundwater recharge.

However, increases in the intensity of rainfall events, when they do occur in the wet periods, provides an opportunity to offset potential losses in storage during periods of drought.  The 2020 UWMP includes a section specially on Water Resiliency Planning which highlights a set of strategies the City has taken to ensure long-term water resiliency and mitigate the impacts from a long-term drought scenario.

These strategies include a multi-source water supply; conservative water demand projections; water use efficiency; water recycling; and future ground water recharge.

Community Resilience Findings
 Increases in temperature and extreme heat events are associated with increases in vector-borne and infectious disease transmission, with future long-term drought scenarios potentially increasing the prevalence of certain vector-borne diseases present on in the central coast region including Lyme disease and valley fever.

Long-Term Drought Vulnerability Score
Adaptive Capacity: High (1.5)
Potential Impact: High (3)
Vulnerability Score:

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3.5

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2.5 WILDFIRE ANALYSIS
This section discusses future changes in wildfire in the County and areas surrounding the City and analyzes how these changes are likely to impact City and its population as well as highlighting what capacity the City and partner agencies already have in place to address these future impacts.

2.5.1 Future Exposure to Wildfire Risk
Wildfire risk is determined by several factors, such as wind speeds, drought conditions, available wildfire fuel (i.e., vegetation), past wildfire suppression activity, and expanding wildland-urban interface (WUI) in and around forests, grasslands, shrub lands, and other natural areas (Westerling 2018). Climate change effects, including increased temperatures and changes to precipitation patterns, will exacerbate many of the factors that contribute to wildfire risk. Recent research has found that increases in global temperatures may be affecting wind patterns and increasing global wind speeds, however these changes would not be experienced uniformly across geographies in the future (Chen 2020). While the impact of climate change on wind speeds is still uncertain, it is important to recognize this potential effect and how it may also contribute to wildfire risk in the future.

Increased variability in precipitation may lead to wetter winters and increased vegetative growth in the spring, and longer and hotter summer periods will lead to the drying of vegetative growth and ultimately result in a greater amount of readily burned fuel for fires. This has already been seen across the state in recent years, with the area burned by wildfires increasing in parallel with rising air temperatures (OEHHA 2018). These factors, combined with the increasing frequency and severity of intense wind conditions, will cause fires to spread rapidly and irregularly, making it difficult to predict fires’ paths and effectively deploy fire suppression forces. Pacific Gas and Electric (PG&E) also has several electrical transmission lines running through the City, which carry significant potential fire risk.

Relative humidity is also an important fire-related weather factor; as humidity levels drop, the dry air causes vegetation moisture levels to decrease, which consequently increases the likelihood that plant material will ignite and burn. With an increase in hotter and drier landscapes, humidity levels may continue to drop and result in higher fuel levels, increasing the risk of wildfire (Schwartz et al., 2015).

Environmental and climatic conditions in and around the City influence the frequency and magnitude of wildfires. The City often experiences high-wind events, such as the Santa Lucia winds, which originate inland and flow westward during the late summer and early fall, counter to the prevailing westerly winds that occur throughout much of the year. Santa Lucia winds contain little humidity, and summers in the City are hot and dry, with precipitation primarily occurring in the winter months. Thus, the combination of the relatively hot, dry Santa Lucia winds occurring at a time when vegetation in the County and the City is particularly dry following the summer months can contribute to the ignition and spread of wildfires. Periods of low relative humidity, when dead trees and vegetation cannot absorb moisture from the air, can also increase the risk of wildfires (City of San Luis Obispo 2011).

The risk of wildfires and subsequent impacts to property and life is greatest at the WUI, which is where urban development borders wildland fuels. Wildfire risk is compounded in areas of the WUI that are also located in or near High or Very High Fire Hazard Severity Zones (VHFHSZ). Figure 19 includes CAL FIRE designated Fire Hazard Severity Zones in and surrounding the City. Portions of southwestern (near the Irish Hills Natural Reserve) and northeastern (near Reservoir Canyon Natural Reserve) parts of the City are located in or near a VHFHSZ, and many of these portions of the City overlap with the WUI. Beyond these areas of the City, the risk of urban fires decreases, with most of the areas surrounding and some locations within the City designated as Moderate Fire Hazard Severity Zone.

Given the City’s urban setting, with minor portions of the City in the VHFHSZ, the analysis for future wildfire risk incorporates County-level changes in wildfire risk to assess how larger regional risks and potential impacts may affect the City. Using a statistical model based on historical climate vegetation, population density, and large fire history, Cal-Adapt provides projections for future annual mean hectares burned within the County when wildfires do occur.

Cal-Adapt does not account for current or planned wildfire management projects. Table 14 and Figure 20 shows the projected change in average annual area burned within the DRAFT
County under low and high emissions

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Source: San Luis Obispo County 2019a
Figure 19 Wildfire Hazard Severity Zones In and Near the C DRAFT
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Sources: Data downloaded from City of San Luis Obispo in 2020 and County of San Luis Obispo in 2020 and downloaded from Cal-Adapt in 2021 Figure 20 Change in Average Annual Maximum Temperature
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in San Luis Obispo County through 2099

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scenarios for the central population growth scenario at midterm and late-century timescales. The total area burned annually by wildfire within the County is expected to rise 15 percent from the historic (1961-1990) annual average of 9,248 hectares to 10,723 hectares in the near-term and increase in the midterm to 10,728 hectares burned annually. In the late-century, average annual area burned in the County is projected to increase to 10,728 hectares and decrease slightly to 9,867 hectares under the low and high emissions scenarios, respectively (CEC 2019d). This reduction in annual average hectares burned in the late-century period is noted in the research conducted to develop the CalAdapt wildfire tool. As vegetation type and fuel amount, structure, and continuity change in the future due to altered disturbance regimes (e.g., changes in the frequency, seasonality, duration, extent and severity of wildfire and infestations by beetles and other pathogens) and climate, future wildfire activity and its response to climatic variability may reduce wildfire activity in some ecosystems (Westerling 2018).

Importantly, Figure 20 illustrates that anticipated changes in wildfire impacts are not homogenous across the County; for instance, the Santa Lucia Wilderness and the La Panza Mountain range located in the southern central portions of the County are projected to experience the largest increases in average area burned over the 21st century under both emissions scenarios. While these areas are outside of the City boundaries and jurisdiction, due to the regional characteristics of wildfire impacts, wildfire events in these areas could affect the City through secondary impacts such as short-term and long-term wildfire evacuees, wildfire smoke, and impacts on the County’s regional transportation network.

Table 14 Changes in Annual Average Area Burned in San Luis Obispo County Average Annual Area Burned
Historic Modeled1
Average Annual Area
Burned
(1961-1990)
Near-Term
(2021-2050)
Midterm
(2035-2064)
Late-Century (2070-2099)
Medium
Emissions High Emissions
Average Annual Area Burned
(hectares) 9,248 10,723 10,728 10,728 9,867
Notes: RCP = Representative Concentration Pathway.
1 Observed historical average annual area burned data were not available from Cal-Adapt; the modeled historical average annual area burned data under the medium emissions scenario was available and used as proxy data.

Source: CEC 2019d.

2.5.2 Wildfire Sensitivities and Impact
This section discusses the City’s existing sensitivities to wildfire impacts and analyzes future wildfire risk in the City, discussed in the three general impact categories (e.g., Natural Systems, Built Environment, Community Resilience).

WILDFIRE AND NATURAL SYSTEMS
Open Space and Ecosystem Functions
Changes in climate variables including increased average annual temperatures, annual climatic water deficit, and relative humidity are all strong predictors of fire occurrence and burned area in semi-arid regions. These changes in
climate variables are projected to increase wildfire risk in open spaces and wooded areas in and surrounding the City.

As noted in the Central Coast Region Report, the size of wildfires in the Central Coast region increases with both air temperature in the month of ignition and with lower rates of precipitation in the 12 months preceding the fire, which create conditions in the natural landscape that increase wildfire risk (Potter 2017).

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Chaparral habitat, which is present in the City’s designated open spaces and surrounding areas, is a fire-dependent evergreen shrubland vegetation community. Human ignitions, fire suppression, and short-term meteorological events have dominated variability in fire activity in chaparral zones in recent decades (Abatzoglou et al. 2016, Mann et al. 2016). Some research has shown that the increasing frequency of fire on these landscapes have caused coastal sage shrubs and chaparral to shift to grasses, including exotic grasses (OPR et al. 2018b). Some research has suggested that annual and some perennial grasses have the strongest effects on fire regimes and act as ecosystem transformers.

Noting that in many ecosystems, the dense growth habit and flammable tissue of invasive grasses create continuous drier fuels that are not present in areas not invaded by non-native grasses (Linder et al. 2018). However, the impact of these shifting vegetation communities on wildfire risk specific to the City is not known at this time.

Plant communities in riparian habitats typically have higher foliar moisture than upland plants. This higher moisture content can help to reduce damage from fire, and further, riparian corridors are often considered to be functional barriers to the spread of wildfire (Pettit and Naiman 2007). However, some invasive plants such as the Giant reed (Arundo donax) and tamarisk (Tamarix spp.) are highly flammable in California riparian systems, and are changing these dynamics. However, both species recover rapidly from fire by regrowth from below-ground plant parts. By contrast, cottonwoods, willows, and other native woody plants are less tolerant of direct exposure to fire. The invasive plants mentioned above as well as Giant reed, a large, bamboolike grass, are making riparian systems fire-prone, particularly in drier periods when this vegetation can increase fuel loads and subsequent wildfire risk (Linder et al. 2018).

Wildfire impacts in riparian zones can reduce canopy cover, resulting in increased water temperatures in creeks and other shaded waterways, as well as increased sediment flux in stream beds and adjacent areas. These changes can directly affect the food web of burned stream areas, increasing the density of algae as well as the potential to decrease terrestrial vegetation inputs, resulting in more invertebrate algae consumers (Cooper et al. 2015).

Post-wildfire conditions can also alter runoff production and streamflow. Studies have shown that post-wildfire streamflow can increase between 82 and 200 percent in the first year after a wildfire event (OPR et al. 2018b). High intensity rainfall events increase the export of sediment flow in affected landscapes while lower intensity events stimulate post-fire regrowth and increase the pace of hydrologic recovery. Research has also shown the floatation of nutrients in post-wildfire streamflows in central portions of the state can affect nearshore marine and estuarine waters. Specifically, post-fire runoff typically has elevated nitrogen concentrations due to the amount of biomass burned in these landscapes during wildfire events (OPR et al. 2018b).

Post-Wildfire Runoff and Debris Flow
Wildfire events can result in post-wildfire scarring on effected landscapes and can alter the hydrologic response of a watershed with the potential for even modest rainstorms to produce dangerous flash floods and debris flows events, in which a mix of water, soils, vegetation, and fragmented rock can rush down mountainsides and funnel into waterways. These events are due to vegetation loss and soil exposure on scarred landscapes, which would otherwise support the stability of soils in steeper terrains. Post-wildfire runoff and debris flows can be affected by several factors but are generally triggered by one of two processes: surface erosion caused by rainfall runoff, and landslides caused by rainfall seeping into the ground. While it is difficult to determine the potential risks of post-wildfire runoff prior to wildfire events, the United States Geological Survey conducts post-fire debris-flow hazard assessments for select fires in the Western U.S that are deemed susceptible to potential post-fire debris-flow events. These assessments analyze burn severity, soil properties, and rainfall characteristics to estimate the probability and volume of debris flows that may occur in response to a design storm and can help communities better prepare for these events. Design storms are defined as hypothetical discrete rainstorms characterized by a specific duration, temporal distribution, rainfall intensity, return frequency, and total depth of rainfall. While the effect of climate change on post-wildfire runoff and debris flow is uncertain, climate change is projected to result in higher intensity rainfall events as well as “whiplash events” with oscillations between extremely dry and extremely wet periods, potentially affecting post-wildfire hazards.

Additionally, drought inhibition of vegetation recovery in areas affected by wildfire can decrease soil stability and increase the risk of post wildfire events (OPR et al. 2018b). Impacts from post-wildfire runoff and debris flow can result in blockage of drainage systems
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term and long-term roadway closures. Impacts from these hazards are more likely to affect areas surrounding waterways and areas with steeper terrain (USGS n.d.).

Key Findings and Policy Considerations
 The increasing frequency of fire on chaparral landscapes have caused coastal sage shrubs and chaparral to shift to grasses, including exotic grasses. Some research has suggested that annual and some perennial grasses have the strongest effects on fire regimes and act as ecosystem transformers.  Wildfire impacts in riparian zones can reduce canopy cover, resulting in increased water temperatures in creeks and other shaded waterways as well as produce increased sediment flux in stream beds and adjacent areas, affecting the food web of burned stream areas and increasing the density of algae in waterways.  Post-wildfire runoff and debris flows can be affected by several factors but are generally triggered by one of two processes: surface erosion caused by rainfall runoff, and landslides caused by rainfall seeping into the ground.

While it is uncertain the effect climate change will have on post-wildfire runoff and debris flows event, climate change is projected to result in higher intensity rainfall events as well as “whiplash events” with oscillations between extremely dry and extremely wet periods, potentially affecting post-wildfire hazards.

WILDFIRE AND THE BUILT ENVIRONMENT
Anthropogenic Factors and Wildfire Risk
As noted extensively in research, while the effects of climate change are projected to increase the frequency and severity of wildfires when they do occur, approximately 95 percent of wildfires in the state are caused by human ignition (Mann et al. 2016). This fact helps to place into perspective the large influence human development has on the fire regime in the state even with the increasing influence of climate change throughout the 21st century. In assessing the influence of climate change on wildfire risk for the City, it is important to recognize and consider the other anthropogenic factors influencing risk. As show in Figure 21, the risk of wildfire is dependent on a variety of factors not excluding
biophysical factors that are affected by climate
change. These determinants, both anthropogenic and
biophysical, can be organized into three categories:

Resources (e.g., land use patterns, vegetation growth), Ignitions (e.g., lightning, accidental ignitions, arson), and Conditions (e.g., precipitation, wind, seasonal
variation).

Modeling conducted on the anthropogenic
influences of future wildfire risk in California note
that there are three dominant anthropogenic
mechanisms aside from climate change that will
heavily influence wildfire risk. These are increasing
ignitions, fire management practices, and the
modification of land cover. The research also
suggests that fire activity will increase in public
lands, especially those surrounding urban areas,
influenced by the promotions of fire suppression
through firefighting and the physical properties of
a dense urban environment (OPR et al. 2018b)
Source: Mann et al. 2016
Interactions of wildfire requirements as regulated by biophysical and anthropogenic influences.

Figure 21 Biophysical and anthropogenic determinants
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