Concord City Council
March 10, 2026

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7.7 NATURAL HAZARD MITIGATION

PLANNING
Mitigation planning is an effective method of reducing risk to life and property from natural disasters such as earthquakes or wildfires.

The City of Concord undertook a policy initiative to adopt and implement a Local Hazard Mitigation Plan (LHMP), which was adopted by the City Council in July 2005, and updated in March 2012. The Plan ensures that emergency services providers are adequately prepared to respond to a major seismic event on the Concord Fault or other Bay Area earthquake fault.

The LHMP was prepared in coordination with the Association of Bay Area Governments (ABAG) with funding and oversight from FEMA. As part of the LHMP, the City identified critical health care facilities, schools, City buildings, and roadways located in areas anticipated to be subjected to high levels of ground shaking, liquefaction, flooding or wildland fires. In order to address these hazards, the City also identified mitigation strategies such as replacement of aging utility lines, seismic retrofitting of facilities critical to providing emergency services, and ensuring coordination among City, County and State agencies that provide emergency service response, as well as private sector organizations such as local hospitals (City of Concord, 2012). The City has adopted the list of mitigation strategies from the LHMP as the Implementation Appendix for this Safety Element in the areas of infrastructure, health, housing, economy, government, environment and land use.

The LHMP initiative was undertaken in accordance with the federal Disaster Mitigation Act of 2000 (DMA 2000), which requires local agencies to adopt an approved Local Hazard Mitigation Plan (LHMP) to be eligible for pre-disaster hazard mitigation funding.

The DMA 2000 establishes a national hazard mitigation program to reduce the loss of life and property, human suffering, economic disruption and disaster assistance costs resulting from natural disasters. The DMA 2000 also provides a source of pre-disaster hazard mitigation funding to assist local governments in implementing effective hazard mitigation measures to ensure the continued functionality of critical services and facilities after a natural disaster.

This first part of the City of Concord’s two-part LHMP is a Multi- jurisdictional Regional Hazard Mitigation Plan entitled, “Taming Natural Disasters,” which was developed in cooperation with other local agencies and the Association of Bay Area Governments. The second part is a Local Annex to the regional plan, with priorities and strategies specific to the City of Concord. The Annex also describes the City’s efforts during the development of the LHMP,

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including participation in workshops, staff training and public input; the Hazard and Risk assessment process and the result of the hazard assessment; the process for identifying mitigation activities and setting priorities; as well as the process for maintaining and updating the Plan.

In 2005, the City adopted its first LHMP. A critical component to a successful mitigation planning project, and a requirement of the In accordance with federal law, is to have the 2005 LHMP was developed using a well-defined, multi-jurisdictional planning process with opportunities for public involvement. The multi- jurisdictional, approach the City undertook emphasizes a thorough and well-documented planning process, using the City’s Internet web page and public outreach process to maximize public and access to project information. This process was also used to solicit input during the five-year update in 2009-2011. In 2012 and 2018, the City adopted updated LHMPs, which were developed using a similar process to the 2005 LHMP.

Both sections of the LHMP have been reviewed and approved by the Federal Emergency Management Agency (FEMA). FEMA
requires the completion and adoption of LHMPs as a continuing condition for eligibility to receive FEMA grant assistance, particularly for pre-disaster planning and projects that prevent disasters.

The 2009-2011 update of the LHMP was adopted by the Concord City Council in March 2012. The updated plan continues to include an “Umbrella” Plan which applies to numerous participating agencies, and an “Annex” which is Concord-specific. The 2012 Annex provides a status update on the City’s ongoing mitigation projects, including identifying a back-up Emergency Operations Center, funding of road and bridge retrofits, setting up memoranda of understanding for the use of schools as emergency shelters, training of City staff and school district personnel, and translation of outreach material into multiple languages. The Annex also identifies new mitigation projects, such as inventory of soft-story buildings and installation of alert and warning systems.

On March 28 and April 18, 2023, respectively, the City adopted and received Federal Emergency Management Administration (FEMA) approval of an updated LHMP for the Concord planning area. Like the previous LHMPs, the 2023 LHMP was developed in accordance with the DMA 2000 and FEMA guidance. The 2023 LHMP
incorporates a process where hazards are identified and profiled, the people and facilities at risk are analyzed, and mitigation actions are developed to reduce or eliminate hazard risk. The implementation of these mitigation actions, which include both short and long-term strategies, involves planning, policy changes, programs, projects,

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and other activities. The City of Concord’s 2023 LHMP is hereby incorporated as part of this Safety and Noise Element and can be found on the City’s website here:
https://cityofconcord.org/DocumentCenter/View/10296.

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GOAL S- 1: AIR QUALITY THAT MEETS STATE

AND FEDERAL STANDARD S

7.8 GOALS, PRINCIPLES, AND POLICIES
Principle S-1.1: Integrate Air Quality Goals into Local Planning and Development Review.

Policy S-1.1.1: Maintain and upgrade traffic control systems to reduce vehicle idling time, emphasizing
commute-route signal synchronization and
vehicle emissions reductions.

Policy S-1.1.2: Site projects in locations and/or in a manner that will reduce air pollution exposure of
sensitive receptors.

Policy S-1.1.3: Require project applicants to implement all feasible control measures to reduce
combustion emissions from construction
equipment.

Policy S-1.1.4: Require developers on a case-by-case basis to comply with the Bay Area Air Quality
Management District regulations in effect at
the time of project approval, including
regulations relating to dust, toxic air
contaminants (TACs), odors, and other air
pollutants or air quality issues.

Policy S-1.1.5: Coordinate with the Bay Area Air Quality Management District (BAAQMD) when
addressing air quality issues related to local
land use proposals.

Examples of these issues include control of
windblown particulates, mechanical
equipment exhaust, and ventilation of parking
garages. Micro-scale impacts can often be
mitigated by changes in design, hours of
operation, or use of filters or other control
devices, and the District may have
information available on “Best Practices”
that can help project applicants.

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Policy S-1.1.6: Provide input and assistance to the BAAQMD’s development and implementation
of regional air quality strategies.

By participating in the regional air quality
planning process, the City can ensure that its
concerns are heard.

Policy S-1.1.7: Require new development to comply with all applicable dust control measures promulgated
by the BAAQMD for new construction.

The BAAQMD includes these in its CEQA
Guidelines in the section addressing
construction emissions.

Policy S-1.1.8: Explore the feasibility of a new City ordinance that would provide a tobacco smoke-free
environment in certain areas of workplace
facilities, specific types of housing, hotels, as
well as parks and other public gathering places
currently not regulated by State and Federal
laws or City ordinance.

Principle S-1.2: Encourage Alternative Modes of
Transportation.

Policy S-1.2.1: Promote pedestrian, bicycle, and transit modes of travel to reduce air pollutant emissions from
automobiles.

Policy S-1.2.2: Encourage establishment of Transportation Demand Management (TDM) programs at
major employment sites and shopping centers,
including provision of preferential carpool
parking and car share programs, bicycle
lockers, BART shuttles, and jitney service.

Policy S-1.2.3: Support the expansion and improvement of local and regional transit systems and
ridesharing programs.

Policy S-1.2.4: Encourage car sharing programs at new high density, mixed use developments, consistent
with the Transportation Control Measures in
BAAQMD’s Clean Air Plan.

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Examples of areas where car sharing could be
implemented include the Concord BART
Station and the Concord Reuse Project site.

Policy S-1.2.5: Work with the school district to implement the Safe Routes to Schools program.

Policy S-1.2.6: Establish preferential parking provisions in the Development Code for car sharing programs.

The City should require preferential parking
for car sharing programs, including reserved
parking spaces for car share vehicles in close
proximity to building entrances.

Policy S-1.2.7: Endeavor to replace City gasoline powered vehicles with hybrid or clean-fuel vehicles
when vehicle replacement purchases are made.

Policy S-1.2.8: Promote walking and bicycling as a means of improving public health and wellness, as well
a means of improving air quality.

Principle S-1.3: Support Regional Air Quality Strategies through Land Use Planning and Site
Design.

Policy S-1.3.1: Encourage provisions for compatible live/work arrangements and telecommuting in
residential areas.

Policy S-1.3.2: Promote infill development to reduce urbanization of open space and agricultural
lands and related increases in automobile
travel.

Policy S-1.3.3: Support transit-oriented development to reduce automobile travel.

Policy S-1.3.4: Encourage mixed use development (combining housing and retail/ office uses) to
reduce the number and length of vehicle trips,
and related air emissions.

Downtown Concord and the area around the
North Concord – Martinez BART Stations both
provide opportunities for such development.

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Policy S-1.3.5: Recognize the potential for the Concord Reuse Project to contribute to regional air quality
improvements by encouraging transit-oriented
development on the site; providing new
workplaces, residences, and services in close
proximity to one another to minimize trip
lengths; and developing viable alternatives to
single passenger vehicle travel.

Policy S-1.3.6: Promote the planting and maintenance of trees and other landscaping to absorb carbon
dioxide and help reduce air pollution levels.

Policy S-1.3.7: Prohibit the installation of wood-burning fireplaces in new residential development
except for EPA-certified wood-burning
devices. Seek grant funding for a wood-
burning stove “changeout” program to
encourage owners of wood-burning stoves in
existing residences to replace them with EPA-
certified devices, and prepare homeowner
information handouts describing low-emission
alternatives to wood-burning fireplaces.

Many homes are equipped with fireplaces,
which are a growing source of localized air
pollution. Smoke released from fireplaces and
wood stoves contains carbon monoxide,
nitrogen dioxide, volatile organic compounds,
and inhalable particulate matter (PM10). The
changeout programs have been successful in
areas of the State where emissions from
wood-burning fireplaces cause significant air
pollution. PG&E and the Hearth Products
Association have offered incentives in the past
in the form of cash rebates to encourage
replacement of old wood-burning appliances
with more efficient ones
Principle S-1.4: Reduce Greenhouse Gas Emissions
Consistent with State Objectives.

Policy S-1.4.1: Prepare and implement climate action plans for the Concord Reuse Project site and for the
city as a whole to reduce greenhouse gas
emissions associated with future development
and existing urban activities.

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GOAL S- 2 : A LIVABLE NOISE ENVIRONMENT
Principle S-2.1: Encourage Land Use Compatibility for
Community Noise Environments.

Policy S-2.1.1: Use the community noise level exposure standards, shown in Figure 7-8, as review
criteria for new land uses.

These standards show noise levels that are
“normally acceptable”, “conditionally
acceptable”, “normally unacceptable” and
“clearly unacceptable” for different types of
land use.

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Figure 7-8: Land Use Compatibility for Community Noise Environments

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Policy S-2.1.2: Require a noise study and mitigation measures for all projects that have noise exposure
greater than “normally acceptable” levels.

The need for mitigation of exterior noise
exposure for development shall be evaluated
on a case-by-case basis. Within
neighborhoods where medium and high
density residential development and mixed use
development is planned, the City will balance
the need for noise mitigation with urban
design considerations, and may not require
exterior walls along streets where an
attractive pedestrian-oriented environment
with porches and front stoops is desired.

Policy S-2.1.3: Consider an increase of four or more dBA to be “significant” if the resulting noise level
would exceed that described as “normally
acceptable” in Figure 7-8.

When an increase in noise would result in a
“significant” impact to residents or
businesses, then mitigation will be required to
reduce noise exposure. If the increase is four
dBA or more, the change in noise is
perceptible and discretionary review is
required. If the increase in noise is three dBA
or less, then the noise impact is considered
insignificant and no mitigation is needed.

By setting a specific threshold of significance
in the General Plan, this policy will facilitate
making a determination of environmental
impact, as required by the California
Environmental Quality Act. It will help the
City judge whether (1) the potential impact of
a development project on the noise
environment warrants mitigation, or (2) a
statement of overriding considerations will be
required.

Policy S-2.1.4: Promote the use of noise attenuation measures to improve the acoustic environment inside
residences where existing residential
development is located on an arterial street.

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Policy S-2.1.5: Conduct periodic noise monitoring and modeling of projected future noise levels in
order to develop noise contour diagrams.

Such diagrams should show probable future
noise levels in the city (see Figure 7-2) and
should be used to evaluate the compatibility of
various land uses in different locations as well
as the need for mitigation measures to reduce
noise levels to acceptable levels.

In addition to Figure 7-2, which is highly
generalized, the City will develop and
maintain a digital GIS shape file which can be
used for more detailed analysis of projected
noise conditions. In addition, noise analysis
will continue to be required on a project by
project basis as future development is
proposed and as future planning is conducted
on the Concord Reuse Project site.

Principle S-2.2: Mitigate Noise Sources.

Policy S-2.2.1: Provide for the mitigation of noise exposure in areas of the City exposed to noise levels in
excess of the “normally acceptable” standards
to the extent feasible (see Figure 7-8).

Policy S-2.2.2: Reduce noise intrusion generated by miscellaneous noise sources through
conditions of approval to control noise-
generating activities.

Policy S-2.2.3: Use the Buchanan Field Airport—Noise Contour Map (see Figure 7-3) for evaluation
of noise impacts around Buchanan Field
Airport.

The Buchanan Field Airport Noise Contours
will be used in conjunction with the noise
contours for car and truck noise during the
development review process.

Policy S-2.2.4: Require new noise sources to use best available control technology (BACT) to
minimize noise emissions.

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GOAL S- 3 : A HIGH LEVEL OF LIFE AND

PROPERTY PROTECTION
Noise from mechanical equipment can be
reduced with soundproofing materials and
sound-deadening insulation; controlling
hours of operation also will reduce noise
impacts during the morning or evening.

Policy S-2.2.5: Require developers to reduce the noise impacts of new development on adjacent
properties through appropriate means.

Increasing setbacks, screening, use of
soundproofing materials and double-glazing
windows, as well as fences and walls,
building orientation and design, and
landscaping all can help buffer or mask
sound.

Principle S-3.1: Reduce Damage Due to Seismic
Hazards.

Policy S-3.1.1: Require as part of the development review process a thorough evaluation of geologic-
seismic and soils conditions and risks.

Policy S-3.1.2: Require all new development to design structures and buildings pursuant to applicable
State and local standards and codes.

On the Concord Reuse Project site, local
codes may be more stringent than State codes
in order to achieve the sustainability and
greenhouse gas reduction goals established
for new development.

Policy S-3.1.3: Require geologic studies to be conducted for all structures, including those not for human
occupancy, located above and below ground
whenever a project is located within an
Earthquake Fault Zone as identified by the
California Geologic Survey.

Policy S-3.1.4: Ensure that the design of roads, pipelines and other public facilities and utilities that cross

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the Concord Fault accommodate the effects of
tectonic creep.

Policy S-3.1.5: Cooperate with appropriate government agencies and public and private organizations
to address seismic hazards.

Principle S-3.2: Minimize the Effects of Landslides and Ground Failure.

Policy S-3.2.1: Require all development on hillsides where the grade exceeds 15 percent to submit a hillside
development (i.e., grading) plan that
demonstrates contoured grading techniques to
ensure that buildings, streets, and drives can be
accommodated safely with a minimum amount
of grading.

Policy S-3.2.2: Restrict development on hillsides with slopes over 30 percent. Where slopes over 30 percent
occur within areas shown for development on
the General Plan Diagram, they should be set
aside as open space where feasible.

With steeper slopes there is a greater risk of a
loss of slope stability and resulting landslides,
which may cause loss of life and property.

Policy S-3.2.3: Require soils and geologic hazards analysis and mitigation as part of development project
review.

Policy S-3.2.4: Regulate all development, including remodeling or structural rehabilitation, to
assure adequate mitigation of safety hazards
on sites having a history or threat of slope
instability, erosion, subsidence, ground failure,
ground rupture, and/or liquefaction.

Policy S-3.2.5: Control erosion of graded areas with revegetation or other acceptable methods.

Policy S-3.2.6: Ensure that comparable levels of hazard mitigation are required for projects affecting
low-income or minority populations, so that
these populations are not disproportionately
affected by new development.

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GOAL S- 4 : FLOOD RISK REDUCTION
Principle S-4.1: Protect the community from risks to lives and property posed by flooding and
stormwater runoff.

Assembly Bill (AB) 162, approved in 2007,
requires local governments to provide specific
flood hazard information in their general
plans. Concord has complied with AB 162 by
including flood hazard maps in Chapter 8 of
this Plan, and by adopting a Flood Plain
Management Ordinance that has been
approved by FEMA. The City has also
documented flood hazards in its Local Hazard
Mitigation Plan. Additional flood hazard data
is being collected for the Community Reuse
Project site.

Policy S-4.1.1: Manage development to ensure compliance with the City’s Flood Management Ordinance
and the City’s Stormwater Management and
Discharge Control Ordinance.

This includes construction and site design
methods to minimize flood damage in the event
of construction within flood hazard areas.

Policy S-4.1.2: Establish engineering design standards for constructing a storm drainage system to
protect against loss of life and property and
minimize risks of flooding. This system
should include a combination of constructed
facilities and natural creeks which are
managed to reduce flood hazards.

All constructed drainage facilities must have
adequate capacity to contain, with sufficient
freeboard, projected runoff from the “design
flood”, a 50-year flood for major facilities, a
25-year flood for secondary facilities, and a
10-year flood for minor facilities.

Policy S-4.1.3: Coordinate storm drainage management with appropriate agencies, including the County
Flood Control and Water Conservation

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GOAL S- 5 : MITIGATED EXPOSURE TO

HAZARDOUS MATERIALS
District, Regional Water Quality Control
Board, Army Corps of Engineers, Department
of Fish & Game and with the Contra Costa
Water District, in the vicinity of the Contra
Costa Canal.

Policy S-4.1.4: Design storm drainage facilities to meet the Contra Costa County Flood Control and Water
Conservation District standards and ensure
adequate and safe flow to minimize flooding.

Policy S-4.1.5: Take the necessary actions to maintain the structural and operational integrity of public
facilities during flood events.

Policy S-4.1.6: Locate new essential public facilities such as hospitals and fire stations out of flood prone
areas.

Policy S-4.1.7: Maintain cooperative working relationships with those agencies with jurisdiction over
flood-related issues, including FEMA and the
County Flood Control and Water Conservation
District.

Additional policies dealing with stormwater
runoff can be found in the Public Facilities and
Utilities Element.

Principle S-5.1: Promote Agency Coordination.

Policy S-5.1.1: Coordinate with the Contra Costa County Department of Environmental Health, the
Department of Toxic Substances Control, the
Department of Defense, the Environmental
Protection Agency, and other appropriate
regulatory agencies, on the review of
proposals at sites which may have toxic
contamination or include hazardous materials
use.

Policy S-5.1.2: Coordinate review of proposed development applications with the appropriate water

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GOAL S- 6: A LOW RISK OF FIRE HAZARD FOR

DEVELOPED COMMUNITIE S NEAR

OPEN SPACE
provider and/or water quality agency for
proposals proximate to water canals,
pipelines, or reservoirs that include handling
potentially hazardous materials.

Plans for spill containment should be
developed as required to comply with federal
and state standards.

Policy S-5.1.3: Control the transport of hazardous materials to minimize potential hazards to the local
population.

Policy S-5.1.4: Prior to reuse of former commercial, industrial, and military sites, require clean-up
to a level consistent with State and federal
regulatory agency standards.

Policy S-5.1.5: Implement hazardous materials remediation plans for the former Concord Naval Weapons
Station (Inland Area) to facilitate the reuse of
the site for development and conservation.

The Area Plan for the Concord Reuse Project
identifies property transfer responsibilities
related to hazardous material clean-up and
the management of future construction and
demolition activities on the site. A range of
pre-development clean up, monitoring, and
site management requirements apply. The
Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA)
requires the federal government to retain
liability for hazardous materials on the site
and to return and remediate any
contamination that may be found in the future.

This will be specified in the deed of transfer as
property on the site is conveyed.”
Principle S-6.1: Promote Effective Fire Protection
Measures for Homes Adjacent to Open
Space.

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GOAL S- 7 : COMPREHENSIVE EMERGENCY AND

SAFETY SERVICES FOR COMMUNITY

PROTECTION
Policy S-6.1.1: Require all development projects adjacent to wildland open space to incorporate firebreaks,
fire resistant landscaping, and/or fire-resistant
building materials in order to minimize
potential damage.

Policy S-6.1.2: Require agreements for maintenance of firebreaks established in connection with
development as a condition of approval in
moderate to high fire hazard areas.

Principle S-7.1: Provide the Highest Standard of Police Protection Services.

Policy S-7.1.1: Evaluate the effects of new development on law enforcement service and take public safety
issues into account when reviewing land use
proposals.

Policy S-7.1.2: Promote effective, community-oriented law enforcement.

Current programs include the Downtown
Footbeat Program, DARE, Safe Streets Now
Program, Neighborhood Watch, and Street
Smart. These also demonstrate how
community-oriented law enforcement can
work.

Policy S-7.1.3: Establish public and private partnerships and cooperate with other emergency service
providers to deliver safe and effective
emergency response.

Principle S-7.2: Facilitate Fire Prevention.

Policy S-7.2.1: Coordinate plans and activities with the Contra Costa County Fire Protection District
(CCCFPD), including siting of fire stations.

Policy S-7.2.2: Require new development to incorporate water systems that meet CCCFPD fire flow

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GOAL S- 8 : EFFECTIVE DISAST ER PLANNING AND

RESPONSE
requirements or to provide adequate on-site
water storage.

Policy S-7.2.3: Ensure that sufficient access for fire protection services is available in all new development.

Policy S-7.2.4: Reduce the potential for fires in potential high- risk areas, as illustrated in Figure 7-5, through
fire-resistant building materials, site design,
and water flow capacity.

Principle S-8.1: Coordinate With Agencies to Plan
Disaster Response.

Policy S-8.1.1: Maintain an ongoing program for disaster response, including participation in all aspects
of emerging, new high-technology solutions.

Policy S-8.1.2: Coordinate disaster response planning with surrounding cities, agencies, and Contra Costa
County.

Policy S-8.1.3: Work with critical use facilities (i.e., hospitals, schools, public assembly facilities,
transportation services) to assure that they can
provide alternate sources of electricity, water,
and sewerage in the event that regular utilities
are interrupted in a disaster.

Policy S-8.1.4: Implement the City’s Local Hazard Mitigation Plan, consistent with the guidelines of the
Federal Emergency Management Agency
(FEMA) and the Disaster Act of 2000, and
seek funding under FEMA’s Hazard
Mitigation Grant Program.

The LHMP is incorporated by reference into
the Concord General Plan.

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Updated 4.2.2024

Assembly Bill 2140 (AB 2140) Fact Sheet
Information for Counties and Cities
What is AB 2140?
Passed in 2006, Assembly Bill No. 2140 (AB 2140 ) allows California counties and cities to be considered for additional state cost-share on eligible Public Assistance projects by adopting their current, FEMA-approved local hazard mitigation plans (LHMPs) into the Safety Element of their General Plan. This adoption, along with other requirements, makes the county or city eligible to be considered for part or all of its local-share costs on eligible Public Assistance projects to be provided by the state through the California Disaster Assistance Act (CDAA ). For more information regarding Public Assistance, please visit Cal OES Public Assistance Division.

How Can AB 2140 Help Counties, Cities, and Your Citizens? For eligible Public Assistance projects, the typical local (non-federal) cost share is 25% of the total project cost.

CDAA can allow the state to pay up to 18.75% of the non- federal share, that would otherwise fall upon the county or city, to pay for eligible Public Assistance projects once the legislature has passed a bill allowing additional state funding after a disaster occurs. Upon approval of the legislature, counties and cities that are AB 2140 compliant are also eligible to be considered for the remaining

6.25% local share to be funded by the state, essentially covering the entire local-share cost for eligible Public Assistance projects. Please note that funding is not guaranteed.

What Do You Need to Know?
 AB 2140 is not a requirement; it is an optional state incentive to help counties and cities become more resilient to natural hazards. Be sure to work with your planning department as the process proceeds.
 There are multiple steps that must be completed before Cal OES can issue a letter of AB 2140 compliance. These steps are listed in detail below in the section What Are the Steps to Become AB 2140 Compliant?  Be aware that adopting the LHMP via a formal resolution is a federal requirement for FEMA to officially “approve” the LHMP and does not make your jurisdiction automatically AB 2140 compliant. AB 2140 is a state incentive which also requires adopting your LHMP into the Safety Element of your General Plan.

However, both adoptions can take place at the same time using the same adoption resolution.
 AB 2140 compliance expires when the LHMP ex
pires. You must re-adopt the
LHMP itself
AND adopt the LHMP into the Safety Element of your General Plan each time you update your LHMP in order to continue compliance.  For multi-jurisdiction hazard mitigation plans (MJHMPs), the county and each city in the MJHMP must adopt its own specific annex into its own General Plan Attachment 2

Updated 4.2.2024

Assembly Bill 2140 (AB 2140) Fact Sheet

Information for Counties and Cities

Safety Element. Annex jurisdictions are not covered under the county’s adoption.
 Special districts are not eligible for AB 2140 compliance as they do not have General Plans.
 For additional
information on General Plan and Safety Element requirements please contact the California Office of Planning and Research (OPR).

What Are the Steps to Become AB 2140 Compliant?

1. Complete and submit an LHMP to the Governor’s Office of Emergency Services (Cal OES). A jurisdiction must have a current, FEMA-approved LHMP. a. Cal OES will provide an initial review and, if applicable, request required revisions based on the
FEMA LHMP Guidance.
b. Once Cal OES has determined the plan has met all FEMA LHMP requirements, Cal OES will then forward the LHMP to FEMA for final review and approval.
c. For questions or assistance, please contact the Cal OES Local Mitigation Planning Unit at [email protected].

2. LHMP adoption AND adoption into the Safety Element of the General Plan a. Adopt the LHMP via a formal resolution following your jurisdiction’s typical procedure once FEMA has issued “approvable pending adoption” (APA) status. Once FEMA receives a signed adoption resolution, they can then issue an official “approval” notice for your LHMP.
i. A sample adoption resolution for your LHMP is provided in Appendix B of the FEMA LHMP Policy Guide.
b. At this time, you may also choose to adopt the LHMP into the Safety Element of your General Plan using the same resolution in order to meet a requirement of AB 2140 compliance (see step 3).
i. Within the Safety Element update adoption resolution, there must be language specific to adopting the LHMP into the Safety Element of the General Plan, and the resolution must be signed and approved before the LHMP expires. This adoption can occur at the same time the LHMP is adopted to comply with FEMA requirements, or it can occur after the LHMP is approved but before it expires after five years.
c. At any time during the life of an approved LHMP a jurisdiction may choose to adopt the LHMP into the Safety Element of their General Plan, however, when the LHMP expires, AB 2140 compliance will also expire.

Updated 4.2.2024

Assembly Bill 2140 (AB 2140) Fact Sheet

Information for Counties and Cities

3. Safety Element Language
a. The local agency must include language specific to the LHMP within the Safety Element of their General Plan and make the LHMP easily accessible in its entirety as a weblink, appendices, or attachment (see step 4).
b. Jurisdictions should follow their own internal procedures for Safety Element language, however, below is sample language that may be used:
i. “The Local Hazard Mitigation Plan (LHMP) for the [Add Jurisdiction Name] planning area was developed in accordance with the Disaster Mitigation Act of
2000 (DMA 2000) and followed FEMA’s
Local Hazard Mitigation Plan guidance. The LHMP incorporates a process where hazards are identified and profiled, the people and facilities at risk are analyzed, and mitigation actions are developed to reduce or eliminate hazard risk. The implementation of these mitigation actions, which include both short and long-term strategies, involve planning, policy changes, programs, projects, and other activities. (Add a web link or language directing to the LHMP attachment or appendix within the Safety Element.

Discussed further in step #4 below.)”

4. LHMP Accessibility and Links
a. The current, approved LHMP must be easily accessible and available to the public viewing the Safety Element. This requirement can be met by linking the LHMP electronically to the General Plan Safety Element or by including the LHMP in its entirety as an attachment or appendix in the Safety Element and referencing its location with the plan. b. Web links should be monitored so that they are in working condition and bring the viewer to the most recent approved version of the LHMP.

5. E-mail the link to the updated General Plan Safety Element web page along with the signed adoption resolution
(s) to the Cal OES AB 2140 inbox
[email protected] for review and approval.

Updated 4.2.2024

Assembly Bill 2140 (AB 2140) Fact Sheet

Information for Counties and Cities

Frequently Asked Questions
Q: Who do I contact if I have additional questions regarding my LHMP or AB 2140 status?
A: For questions regarding AB 2140 compliance please
contact
[email protected]. For questions pertaining to your LHMP, please contact the Cal OES Local Hazard Mitigation Planning team at
[email protected].

Q: If a county is AB 2140 compliant, are its cities automatically covered? A: No. Each county and city must:

1. Have either your own stand-alone LHMP or have an annex in a MJHMP.

2. Have adopted your approved stand-alone LHMP or annex into your own General Plan Safety Element.

Q: Can a jurisdiction obtain AB 2140 compliance before their LHMP is approvable pending adoption (APA) from FEMA?
A: No. The LHMP must be either APA or officially “approved” by FEMA before you may adopt to obtain AB 2140 compliance.

Q: Are special districts covered under their county’s LHMP since they do not have their own general plan?
A: No. Special districts are not qualified for additional cost share under AB 2140 because they do not have a General Plan.

Q: If a county or city becomes AB 2140 compliant, does this compliance last forever?
A: No. AB 2140 compliance expires on the day the LHMP expires. You must re-adopt your LHMP into your General Plan Safety Element each time you update your LHMP.

Q: Once a county or city becomes AB 2140 compliant, are they guaranteed funding?
A: No. You will be eligible to be considered for additional CDAA funding upon approval of the legislature. There is no guarantee of funding.

Q: Can a city or county adopt their LHMP to obtain AB 2140 compliance at the same time they adopt their LHMP to fulfill the FEMA requirement when the LHMP is approvable pending adoption?
A: Yes, this is a viable option. It is crucial, however, that Cal OES receives a copy of the adoption resolution to ensure compliance. Your jurisdiction is

Updated 4.2.2024

Assembly Bill 2140 (AB 2140) Fact Sheet

Information for Counties and Cities

not compliant until Cal OES has documentation and has issued a compliance letter.

Q: If the actual LHMP is added to the General Plan, but not within the Safety Element, is language still required in the Safety Element? A: Yes, language specific to the LHMP and a web link, appendix, or language within the Safety Element that directs the public to the most current, approved LHMP in its entirety is required to be in the Safety Element.

AB 2140 Compliance Checklist
In order to issue a letter of AB 2140 compliance, Cal OES will review and verify that your jurisdiction has performed the following:

 Ha
s a current, FEMA-approved or approvable pending adoption (APA) LHMP.  Formally adopted the LHMP via resolution.
 Formally adopted the most current, approved LHMP into the Safety Element of your General Plan via resolution.
 Included language within the Safety Element of your General Plan that references your LHMP.
 Included a web link, appendix, or language within the Safety Element that directs the public to the most current, approved LHMP in its entirety.  E-mailed the link to the updated General Plan Safety Element web page along with the signed, adoption resolution(s) to the Cal OES AB 2140 inbox [email protected] for review and approval.

For AB 2140 Questions: [email protected]

For LHMP Questions: [email protected]

For Public Assistance and CDAA Questions: [email protected]

Attachment 3

Exhibit A

City of Concord Hazard Mitigation Plan
Prepared for Prepared by
City of Concord Tetra Tech
1950 Parkside Drive
Concord, California 94519
https://cityofconcord.org/
1999 Harrison Street
Suite 500
Oakland, CA 94612
Phone: 510.302.6300
Fax: 510.433.0830
tetratech.com
Tetra Tech Project # 103S8478
\\tt.local\gfs\USVolume2\Legacy\tts121fs1\EMI\Data\EMCR_Projects\California\Concord\HMP_2022\Plan Development\Plan Documents\2023- 03_AgencySubmittalDraft\2023_Concord_HMP_AgencySubmittalDraft.docx

City of Concord Hazard Mitigation Plan Contents
v

CONTENTS
Contents ............................................................................................................................................. v Acknowledgments ............................................................................................................................. xii Definitions and Acronyms ................................................................................................................ xiii Executive Summary ......................................................................................................................... xviii PART 1— PLANNING PROCESS AND COMMUNITY PROFILE

1. Introduction to Hazard Mitigation Planning ................................................................................................................. 1-1

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

1.2 Who Will Benefit From This Plan? ........................................................................................................................ 1-2

1.3 Contents of This Plan .............................................................................................................................................. 1-2

2. Plan Update—What Has Changed .................................................................................................................................. 2-1

2.1 The Previous Plan ..................................................................................................................................................... 2-1

2.2 Why Update? ............................................................................................................................................................. 2-1

2.3 The Updated Plan—What Is Different? ............................................................................................................... 2-2

3. Plan Development Approach ........................................................................................................................................... 3-1

3.1 Formation of the Planning Team ........................................................................................................................... 3-1

3.2 Defining the Planning Area ..................................................................................................................................... 3-1

3.3 The Steering Committee .......................................................................................................................................... 3-3

3.4 Coordination with Stakeholders and Other Agencies ......................................................................................... 3-3

3.5 Review of Existing Programs .................................................................................................................................. 3-4

3.6 Public Involvement ................................................................................................................................................... 3-5

3.7 Plan Development Chronology/Milestones ....................................................................................................... 3-11

4. City of Concord Profile ..................................................................................................................................................... 4-1

4.1 City Government ...................................................................................................................................................... 4-1

4.2 Historical Overview .................................................................................................................................................. 4-1

4.3 Physical Setting .......................................................................................................................................................... 4-2

4.4 Sensitive Resources ................................................................................................................................................... 4-3

4.5 Development Profile ................................................................................................................................................ 4-4

4.6 Demographic Profile .............................................................................................................................................. 4-10

4.7 Economy .................................................................................................................................................................. 4-15

5. Hazards Addressed in This Plan ...................................................................................................................................... 5-1

5.1 Major Past Hazard Events ....................................................................................................................................... 5-1

5.2 Identified Hazards of Concern ............................................................................................................................... 5-2

6. Regulations and Programs ................................................................................................................................................. 6-1

6.1 Federal and State ....................................................................................................................................................... 6-1

6.2 City of Concord ......................................................................................................................................................... 6-4

6.3 Capability Assessment .............................................................................................................................................. 6-5 PART 2— RISK ASSESSMENT

7. Risk Assessment Methodology ......................................................................................................................................... 7-1

7.1 Risk Assessment Tools............................................................................................................................................. 7-1

City of Concord Hazard Mitigation Plan Contents
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7.2 Risk Assessment Approach ..................................................................................................................................... 7-2

7.3 Sources of Data Used ............................................................................................................................................... 7-4

7.4 Limitations ................................................................................................................................................................. 7-5

8. Dam and Levee Failure ...................................................................................................................................................... 8-1

8.1 General Background ................................................................................................................................................. 8-1

8.2 Hazard Profile............................................................................................................................................................ 8-4

8.3 Exposure and Vulnerability ..................................................................................................................................... 8-9

8.4 Future Trends in Development .............................................................................................................................. 8-9

8.5 Scenario ...................................................................................................................................................................... 8-9

8.6 Issues ........................................................................................................................................................................... 8-9

9. Drought ................................................................................................................................................................................ 9-1

9.1 General Background ................................................................................................................................................. 9-1

9.2 Hazard Profile............................................................................................................................................................ 9-6

9.3 Exposure and Vulnerability ..................................................................................................................................... 9-9

9.4 Future Trends in Development ............................................................................................................................ 9-10

9.5 Scenario .................................................................................................................................................................... 9-10

9.6 Issues ......................................................................................................................................................................... 9-10

10. Earthquake ....................................................................................................................................................................... 10-1

10.1 General Background ............................................................................................................................................. 10-1

10.2 Hazard Profile ....................................................................................................................................................... 10-6

10.3 Exposure .............................................................................................................................................................. 10-13

10.4 Vulnerability ......................................................................................................................................................... 10-13

10.5 Future Trends in Development ........................................................................................................................ 10-23

10.6 Scenario ................................................................................................................................................................ 10-23

10.7 Issues ..................................................................................................................................................................... 10-24

11. Flood ................................................................................................................................................................................ 11-1

11.1 General Background ............................................................................................................................................. 11-1

11.2 Hazard Profile ....................................................................................................................................................... 11-3

11.3 Exposure .............................................................................................................................................................. 11-11

11.4 Vulnerability ......................................................................................................................................................... 11-14

11.5 Future Trends ...................................................................................................................................................... 11-17

11.6 Scenario ................................................................................................................................................................ 11-17

11.7 Issues ..................................................................................................................................................................... 11-18

12. Landslide .......................................................................................................................................................................... 12-1

12.1 General Background ............................................................................................................................................. 12-1

12.2 Hazard Profile ....................................................................................................................................................... 12-4

12.3 Exposure ................................................................................................................................................................ 12-7

12.4 Vulnerability ........................................................................................................................................................... 12-8

12.5 Future Trends in Development .......................................................................................................................... 12-9

12.6 Scenario ................................................................................................................................................................ 12-10

12.7 Issues ..................................................................................................................................................................... 12-10

13. Severe Weather ............................................................................................................................................................... 13-1

13.1 General Background ............................................................................................................................................. 13-1

13.2 Hazard Profile ....................................................................................................................................................... 13-5

13.3 Exposure ................................................................................................................................................................ 13-9

13.4 Vulnerability ........................................................................................................................................................... 13-9

13.5 Future Trends in Development ........................................................................................................................ 13-11

City of Concord Hazard Mitigation Plan Contents
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13.6 Scenario ................................................................................................................................................................ 13-11

13.7 Issues ..................................................................................................................................................................... 13-11

14. Wildfire ............................................................................................................................................................................. 14-1

14.1 General Background ............................................................................................................................................. 14-1

14.2 Secondary Impacts ................................................................................................................................................ 14-1

14.3 Hazard Profile ....................................................................................................................................................... 14-1

14.4 Exposure and Vulnerability ................................................................................................................................. 14-3

14.5 Future Trends in Development .......................................................................................................................... 14-3

14.6 Scenario .................................................................................................................................................................. 14-3

14.7 Issues ....................................................................................................................................................................... 14-3

15. Climate Change ............................................................................................................................................................... 15-1

15.1 General Background ............................................................................................................................................. 15-1

15.2 Projected Future Impacts for Concord ............................................................................................................. 15-5

15.3 Vulnerability Assessment— Hazards of Concern ........................................................................................... 15-8

15.4 Issues ..................................................................................................................................................................... 15-14

16. Other Hazards of Interest ............................................................................................................................................. 16-1

16.1 Human-Caused Hazards ...................................................................................................................................... 16-1

16.2 Infectious Disease ............................................................................................................................................... 16-29

17. Risk Ranking.................................................................................................................................................................... 17-1

17.1 Probability of Occurrence ................................................................................................................................... 17-1

17.2 Impact ..................................................................................................................................................................... 17-2

17.3 Risk Rating and Ranking ...................................................................................................................................... 17-4 PART 3— MITIGATION STRATEGY

18. Goals and Objectives ..................................................................................................................................................... 18-1

18.1 Mission Statement ................................................................................................................................................. 18-1

18.2 Goals ....................................................................................................................................................................... 18-1

18.3 Objectives............................................................................................................................................................... 18-1

19. Mitigation Best Practices and Adaptive Capacity ...................................................................................................... 19-1

19.1 Mitigation Best Practices ..................................................................................................................................... 19-1

19.2 Adaptive Capacity ................................................................................................................................................. 19-8

20. Action Plan and Implementation ................................................................................................................................. 20-1

20.1 Status of Previous Plan Actions ......................................................................................................................... 20-1

20.2 Action Plan ............................................................................................................................................................ 20-1

20.3 Action Plan Prioritization .................................................................................................................................... 20-5

20.4 Classification of Actions ...................................................................................................................................... 20-7

21. Plan Adoption, Implementation and Maintenance ................................................................................................... 21-1

21.1 Plan Adoption ....................................................................................................................................................... 21-1

21.2 Plan Implementation ............................................................................................................................................ 21-1

21.3 Plan Maintenance .................................................................................................................................................. 21-1

22. References .............................................................................................................................................................................. 1

City of Concord Hazard Mitigation Plan Contents
viii
Appendices
Appendix A. Outreach Survey & Results
Appendix B. Summary of Federal and State Agencies, Programs and Regulation Appendix C. Data Sources and Methods Used for Mapping
Appendix D. Detailed Risk Assessment Results
Appendix E. Cal-Adapt Climate Projection Snapshot Report for the City of Concord Appendix F. Review of Previous Plan Actions
Appendix G. Progress Report Template
Appendix H. City Adoption Resolution and FEMA Approval

Tables
Table 2-1. Plan Changes Crosswalk ............................................................................................................................................. 2-3 Table 3-1. Steering Committee Members ................................................................................................................................... 3-3 Table 3-2. Summary of Public Meetings and Events ............................................................................................................. 3-10 Table 3-3. Plan Development Chronology/Milestones ......................................................................................................... 3-12 Table 4-1. Identified Soil Types in Contra Costa County ........................................................................................................ 4-3 Table 4-2. Average Concord Climate Data ................................................................................................................................ 4-3 Table 4-3. General Plan Land Use within the Planning Area ................................................................................................. 4-5 Table 4-4. Distribution of Buildings in the Planning Area by Use Type .............................................................................. 4-5 Table 4-5. Planning Area Critical Facilities ................................................................................................................................ 4-6 Table 4-6. Recent and Expected Future Development Trends .............................................................................................. 4-9 Table 4-7. Annual Population Data ........................................................................................................................................... 4-10 Table 4-8. Comparative Statistics for Renter-Occupied and Owner-Occupied Housing Units ..................................... 4-15 Table 5-1. Federal Disaster Declarations Applying to Contra Costa County ....................................................................... 5-1 Table 5-2. City of Concord Hazard Comparison with California State Hazards ................................................................. 5-2 Table 6-1. Summary of Relevant Federal Agencies, Programs and Regulations .................................................................. 6-1 Table 6-2. Summary of Relevant State Agencies, Programs and Regulations ...................................................................... 6-2 Table 6-3. Planning and Regulatory Capability .......................................................................................................................... 6-6 Table 6-4. Administrative and Technical Capability ................................................................................................................. 6-8 Table 6-5. Fiscal Capability ........................................................................................................................................................... 6-9 Table 6-6. Community Classifications ........................................................................................................................................ 6-9 Table 6-7. Development and Permitting Capability ............................................................................................................... 6-10 Table 6-8. National Flood Insurance Program Compliance ................................................................................................. 6-10 Table 6-9. Education and Outreach .......................................................................................................................................... 6-11 Table 6-10. Adaptive Capacity for Climate Change ................................................................................................................ 6-12 Table 7-1. Hazus Model Data Documentation ......................................................................................................................... 7-5 Table 8-1. State of California Downstream Hazard Potential Classification ........................................................................ 8-3

City of Concord Hazard Mitigation Plan Contents
ix
Table 8-2. Dams with Potential to Impact the City of Concord ............................................................................................ 8-6 Table 8-3. Project Levees in Protecting the City of Concord ................................................................................................. 8-8 Table 9-1. State Drought Management Program ...................................................................................................................... 9-4 Table 10-1. Mercalli Scale and Peak Ground Acceleration Comparison ............................................................................ 10-3 Table 10-2. NEHRP Soil Classification System ...................................................................................................................... 10-5 Table 10-3. Earthquakes Magnitude 5.0 or Larger Within 100-mile Radius of the Planning Area ................................. 10-6 Table 10-4. Earthquake Probabilities for the San Francisco Bay Area Region, 2014-2043 ........................................... 10-11 Table 10-5. Earthquakes Modeled for Risk Assessment ...................................................................................................... 10-13 Table 10-6. Estimated Earthquake Impact on Persons and Households ......................................................................... 10-13 Table 10-7. Age of Structures in Planning Area .................................................................................................................... 10-18 Table 10-8. Loss Estimates for Modeled Earthquake Scenarios ........................................................................................ 10-18 Table 11-1. History of Flood Events ........................................................................................................................................ 11-7 Table 11-2. Summary of Peak Discharges Within the Planning Area ............................................................................... 11-10 Table 11-3. Exposed Population and Property in Evaluated Flood Hazard Zones ........................................................ 11-12 Table 11-4. Estimated Flood Impacts on Households and Residents ............................................................................... 11-14 Table 11-5. Estimated Impact of a Flood Event in the Planning Area ............................................................................. 11-15 Table 12-1. Landslide Events Near the City of Concord ...................................................................................................... 12-5 Table 12-2. Exposed Population and Property in Mapped Landslide Risk Zones ............................................................ 12-8 Table 12-3. Loss Potential for Landslide (Aggregate from Very High and High Risk Area Exposure) ........................ 12-9 Table 13-1. Beaufort Wind Chart .............................................................................................................................................. 13-3 Table 13-2. Triggers for Public Safety Power Shutoff Events .............................................................................................. 13-5 Table 13-3. Severe Weather Events in Concord and the Surrounding Area, January 2002 – September 2022 ............ 13-7 Table 13-4. Loss Potential for Severe weather ...................................................................................................................... 13-10 Table 15-1. Climate Projections for the City of Concord ...................................................................................................... 15-6 Table 16-1. Event Profiles for Terrorism ................................................................................................................................. 16-2 Table 16-2. Common Mechanisms for Cyber-Attacks ........................................................................................................... 16-6 Table 16-3. Hazardous Materials Spills in the City of Concord Reported to Cal OES, 2018-2022 ............................. 16-12 Table 16-4. Criticality Factors................................................................................................................................................... 16-20 Table 16-5. Vulnerability Criteria ............................................................................................................................................. 16-21 Table 16-6. FEMA Standard Value for Loss of Service for Utilities and Roads/Bridges .............................................. 16-23 Table 19-1. Alternatives to Mitigate the Dam and Levee Failure Hazard ........................................................................... 19-2 Table 19-2. Alternatives to Mitigate the Drought Hazard ..................................................................................................... 19-3 Table 19-3. Alternatives to Mitigate the Earthquake Hazard ................................................................................................ 19-4 Table 19-4. Alternatives to Mitigate the Flood Hazard .......................................................................................................... 19-5 Table 19-5. Alternatives to Mitigate the Landslide Hazard ................................................................................................... 19-6 Table 19-6. Alternatives to Mitigate the Severe Weather Hazard ......................................................................................... 19-7 Table 19-7. Alternatives to Mitigate the Wildfire Hazard ...................................................................................................... 19-8 Table 20-1. Action Plan ............................................................................................................................................................... 20-2 Table 20-2. Mitigation Action Priority ...................................................................................................................................... 20-7 Table 20-3. Classification of Mitigation Actions ..................................................................................................................... 20-8 Table 21-1. Plan Maintenance Matrix ....................................................................................................................................... 21-2

City of Concord Hazard Mitigation Plan Contents
x
Figures
Figure 3-1. Planning Area ............................................................................................................................................................. 3-2 Figure 3-2. Sample Page from Survey Distributed to the Public ............................................................................................ 3-7 Figure 3-3. Hazard Awareness Booth at the Concord Senior Center Craft Fair ................................................................. 3-8 Figure 3-4. Surveys Distributed at the Concord Senior Center Craft Fair ............................................................................ 3-8 Figure 3-5. Hazard Mitigation Booth Volunteers at the Concord Tree Lighting Ceremony ............................................. 3-8 Figure 3-6. Surveys Distributed at the Concord Tree Lighting Ceremony ........................................................................... 3-8 Figure 3-7. Hazard Mitigation Plan Webpage on the City of Concord Website .................................................................. 3-9 Figure 3-8. Example Story Map Data Page .............................................................................................................................. 3-10 Figure 4-1. Critical Facilities (1 of 2) ........................................................................................................................................... 4-7 Figure 4-2. Critical Facilities (2 of 2) ........................................................................................................................................... 4-8 Figure 4-3. California and City of Concord Population Growth.......................................................................................... 4-10 Figure 4-4. Concord Age Distribution ...................................................................................................................................... 4-12 Figure 4-5. Concord Race Distribution .................................................................................................................................... 4-13 Figure 4-6. Concord Ethnicity Distribution ............................................................................................................................. 4-14 Figure 4-7. High Social Vulnerability Areas in the Planning Area ....................................................................................... 4-16 Figure 4-8. Industry in the Planning Area ................................................................................................................................ 4-17 Figure 4-9. Occupations in the City of Concord ..................................................................................................................... 4-18 Figure 4-10. California and Contra Costa County Unemployment Rate ............................................................................ 4-18 Figure 8-1. High or Extremely High Hazard Dams with Potential to Affect the Planning Area ..................................... 8-5 Figure 8-2. Dam Failure Inundation Areas ................................................................................................................................ 8-7 Figure 9-1. Example Drought Index Maps (November and December 2022) .................................................................... 9-3 Figure 9-2. Percent of Contra Costa County Affected by USDM Ratings, 2000 –2023 .................................................... 9-7 Figure 10-1. 2018 USGS National Seismic Hazard Map ....................................................................................................... 10-5 Figure 10-2. Significant Known Faults in the Bay Area ......................................................................................................... 10-7 Figure 10-3. NEHRP Soil Classification ................................................................................................................................. 10-9 Figure 10-4. Liquefaction Susceptibility .................................................................................................................................. 10-10 Figure 10-5. PGA with 2-Percent Probability of Exceedance in 50 Years ....................................................................... 10-12 Figure 10-6. Earthquake Scenario—100-Year Probabilistic Event .................................................................................... 10-14 Figure 10-7. Earthquake Scenario—Concord-Green Valley Fault M6.8 .......................................................................... 10-15 Figure 10-8. Earthquake Scenario—Hayward (Haywired Scenario) M7.05 ...................................................................... 10-16 Figure 10-9. Earthquake Scenario—Mount Diablo Fault M6.7 ......................................................................................... 10-17 Figure 10-10. Critical Facility Damage Potential, 100-Year Probabilistic Event ............................................................. 10-19 Figure 10-11. Critical Facility Damage Potential, Concord-Green Valley Fault Scenario (M6.8) ................................. 10-20 Figure 10-12. Critical Facility Damage Potential, Haywired Fault Scenario (M7.05) ...................................................... 10-20 Figure 10-13. Critical Facility Damage Potential, Mount Diablo Fault Scenario (M6.7) ................................................ 10-21 Figure 10-14. Critical Facility Functionality, 100-Year Probabilistic Event ...................................................................... 10-21 Figure 10-15. Critical Facility Functionality, Concord-Green Valley Fault Scenario (M6.8) ......................................... 10-22 Figure 10-16. Critical Facility Functionality, Haywired Fault Scenario (M7.05) .............................................................. 10-22 Figure 10-17. Critical Facility Functionality, Mount Diablo Fault Scenario (M6.7) ........................................................ 10-23 Figure 11-1. Special Flood Hazard Areas ................................................................................................................................. 11-9 Figure 11-2. Exposed Structures in 1% Annual Chance Flood Zone by Occupancy Class .......................................... 11-12 Figure 11-3. Exposed Structures in 0.2% Annual Chance Flood Zone by Occupancy Class ....................................... 11-12

City of Concord Hazard Mitigation Plan Contents
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Figure 11-4. Number of Critical Facilities in Mapped Flood Hazard Areas ..................................................................... 11-13 Figure 11-5. Critical Facilities in Mapped Flood Hazard Areas as % of Total in Category ........................................... 11-13 Figure 11-6. Critical Facilities Affected by the 1% and 0.2% Annual Chance Floods .................................................... 11-16 Figure 11-7. Average Damage to Critical Facilities from 1% and 0.2% Annual Chance Floods .................................. 11-16 Figure 12-1. Common Landslide Types ................................................................................................................................... 12-2 Figure 12-2. Landslide Susceptibility ......................................................................................................................................... 12-6 Figure 12-3. Exposed Structures in Moderate Landslide Risk Area by Occupancy Class ................................................ 12-8 Figure 12-4. Exposed Structures in High Landslide Risk Area by Occupancy Class ........................................................ 12-8 Figure 13-1. Weather Fatalities Including Extreme Heat ...................................................................................................... 13-2 Figure 13-2. NWS Heat Risk Forecasting System ................................................................................................................... 13-8 Figure 15-1. Global Carbon Dioxide Concentrations Over Time ....................................................................................... 15-2 Figure 15-2. California’s 2020 Greenhouse Gas Emission Inventory by Sector ............................................................... 15-2 Figure 15-3. Observed and Projected Yearly Maximum Temperatures in the City of Concord ..................................... 15-6 Figure 15-4. Observed and Projected Average Annual Precipitation in the City of Concord ......................................... 15-7 Figure 15-5. Observed and Projected Average Annual Wildfire Burn Area in the City of Concord ............................. 15-7 Figure 16-1. Pipelines in Concord ........................................................................................................................................... 16-15 Figure 17-1. Probability Factors for Hazards of Concern ..................................................................................................... 17-2 Figure 17-2. Impact Factors for Hazards of Concern ............................................................................................................ 17-3 Figure 17-3. Total Risk Rating for Hazards of Concern ........................................................................................................ 17-4 Figure 17-4. Hazard Risk Ranking ............................................................................................................................................. 17-4

City of Concord Hazard Mitigation Plan Acknowledgments
xii

ACKNOWLEDGMENTS
City of Concord
• Trish Beirne, Emergency & Volunteer Services Manager, City of Concord • Bruce Davis, Senior Civil Engineer, City of Concord
• Kevin Marstall, Community Development Director, City of Concord • Jennifer Nylander, Administrative Coordinator, City of Concord • Carlton Thompson, Engineer, City of Concord
Consultants
• Bart Spencer, Tetra Tech, Inc., Project Manager
• Rob Flaner, Tetra Tech, Inc., Program Manager
• Megan Brotherton, Tetra Tech, Inc., Planner
• Nate Stueve, Tetra Tech, Inc., Planner
• Jake Poland, Tetra Tech, Inc., Planner
• Carol Bauman, Tetra Tech, Inc., Risk Assessment Lead
• Dan Portman, Tetra Tech, Inc., Technical Editor
Special Acknowledgments
Development of this plan would not have been possible without the commitment of the City of Concord Hazard Mitigation Plan Steering Committee. The dedication of this committee’s volunteer members to allocate their time to developing the plan is greatly appreciated. Also, residents of Concord are commended for their participation in the outreach strategy identified by the Steering Committee. This outreach success will set the course to successful implementation of this plan during its next performance period.

City of Concord Hazard Mitigation Plan Definitions and Acronyms xiii

DEFINITIONS AND ACRONYMS
°F—Degrees Fahrenheit

0.2 percent-annual-chance flood—The flood that has a

0.2 percent chance of being equaled or exceeded in any
given year; often referred to as the 500-year flood

0.2-percent-annual-chance (500-year) floodplain—The
area flooded by the flood that has a 0.2-percent chance of being equaled or exceeded in a given year.
1 percent-annual-chance flood—The flood that has a
1 percent chance of being equaled or exceeded in any given year; often referred to as the 100-year flood
1-percent-annual-chance (100-year) floodplain—The area
flooded by the flood that has a 1-percent chance of being equaled or exceeded in a given year. The 1-percent-annual- chance flood is the standard used by most federal and state agencies.

AB—Assembly Bill
ADA—Americans with Disabilities Act
asset—Any man-made or natural feature that has value,
including people; buildings; infrastructure, such as bridges, roads, sewers, and water systems; lifelines, such as
electricity and communication resources; and environmental, cultural, or recreational features such as parks, wetlands, and landmarks
base flood—The flood having a 1% chance of being
equaled or exceeded in any given year, also known as the “100-year” or “1 percent annual chance” flood. The base flood is a statistical concept used to ensure that all
properties subject to the National Flood Insurance Program (NFIP) are protected to the same degree against flooding. basin—The area within which all surface water—whether
from rainfall, snowmelt, springs, or other sources—flows to a single water body or watercourse. The boundary of a river basin is defined by natural topography, such as hills,
mountains, and ridges. Basins are also referred to as
“watersheds.”
benefit/cost analysis—A systematic, quantitative method of comparing projected benefits to projected costs of a project or policy. It is used as a measure of cost effectiveness. benefit—A net project outcome and is usually defined in monetary terms. Benefits may include direct and indirect effects. For the purposes of benefit/cost analysis of
proposed mitigation measures, benefits are limited to
specific, measurable, risk reduction factors, including reduction in expected property losses (buildings, contents, and functions) and protection of human life.

BRIC—Building Resilient Infrastructure and Communities
CAL FIRE—California Department of Forestry and Fire
Protection
Cal OES—California Office of Emergency Services
capability assessment—An analysis of a community’s
capacity to address threats associated with hazards. The assessment includes two components: an inventory of an
agency’s mission, programs, and policies, and an analysis of its capacity to carry them out.

CCR—California Code of Regulations
CDBG-DR—Community Development Block Grant Disaster
Recovery grants
CDC—Centers for Disease Control and Prevention
CEQA—California Environmental Quality Act
CFR—Code of Federal Regulations
civil unrest— A violent public disturbance of the peace by three or more individuals. Civil unrest is a result of
displeasure with or protest against socio-political problems and varies in severity. The tactics can range from permitted protest to criminal activities, all of which can escalate into chaos for those participating in the activities as well as for the general public.
climate change—A change in global or regional climate
patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.

Community Rating System (CRS)—A voluntary program
under the NFIP that rewards participating communities
(provides incentives) for exceeding the minimum
requirements of the NFIP and completing activities that reduce flood hazard risk by providing flood insurance
premium discounts.
critical area: An area defined by state or local regulations as deserving special protection because of unique natural features or its value as habitat for a wide range of species of flora and fauna. A sensitive/critical area is usually subject to more restrictive development regulations.
critical facility: Facilities and infrastructure that are critical to the health and welfare of the population. These become especially important after any hazard event occurs.

CRS—Community Rating System
CWA—Clean Water Act
cyber-attack—An attempt to damage, disrupt, or gain
unauthorized access to a computer, computer system, or
electronic communications network.
dam failure—An uncontrolled release of impounded water
due to structural deficiencies in dam.
dam—Any artificial barrier or controlling mechanism that can or does impound or divert water.
debris flow: Dense mixtures of water-saturated debris that move down-valley; looking and behaving much like flowing concrete. They form when loose masses of unconsolidated material are saturated, become unstable, and move down
slope. The source of water varies but includes rainfall, melting snow or ice, and glacial outburst floods.

DFIRM—Digital Flood Insurance Rate Map

City of Concord Hazard Mitigation Plan Definitions and Acronyms xiv
Disaster Mitigation Act (DMA; Public Law 106-390)—The
latest federal legislation enacted to encourage and promote proactive, pre-disaster planning as a condition of receiving certain federal financial assistance.

DMA —Disaster Mitigation Act
drought—The cumulative impacts of long periods of dry
weather. These can include deficiencies in surface and
subsurface water supplies and general impacts on health, well-being, and quality of life.

DTSC—Department of Toxic Substances Control
DWR—Department of Water Resources (California)
EAP—Emergency action plan
earthquake—The shaking of the ground caused by an
abrupt shift of rock along a fracture in the earth or a contact zone between tectonic plates.
ecosystem services—An ecosystem service is any positive benefit that wildlife or ecosystems provide to people. The benefits can be direct or indirect—small or large.
emergency action plan—A formal document that identifies potential emergency conditions at a dam and specifies
actions to be followed to minimize property damage and loss of life. The plan specifies actions the dam owner should take to alleviate problems at a dam. It contains procedures and information to assist the dam owner in issuing early warning and notification messages to responsible downstream
emergency management authorities of the emergency
situation. It also contains inundation maps to show
emergency management authorities the critical areas for action in case of an emergency.
epicenter—The point on the earth’s surface directly above the hypocenter of an earthquake. The location of an
earthquake is commonly described by the geographic
position of its epicenter and by its focal depth.
epidemic—The spread of an infectious disease beyond a
local population, reaching people in a wider geographical area. Several factors determine whether an outbreak will become an epidemic: the ease with which the disease
spreads from vectors, such as animals, to people, and the ease with which it spreads from person to person.

ESA—Endangered Species Act
exposure—Exposure is defined as the number and dollar
value of assets considered to be at risk during the
occurrence of a specific hazard.
extreme heat—Temperatures that hover 10 ºF or more
above the average high temperature for a region and last for several days.
fault—A fracture in the earth’s crust along which two blocks of the crust have slipped with respect to each other.

FBI—Federal Bureau of Investigation
FCWCD—Flood Control and Water Conservation District
federal disaster declaration—Declarations for events that cause more damage than state and local governments and
resources can handle without federal government
assistance. A federal disaster declaration puts into motion long-term federal recovery programs, some of which are
matched by state programs, to help disaster victims,
businesses, and public entities.

FEMA—Federal Emergency Management Agency
FERC—Federal Energy Regulatory Commission
FHSZ—Fire hazard severity zone
fire behavior: Fire behavior refers to the physical
characteristics of a fire and is a function of the interaction between the fuel characteristics (such as type of vegetation and structures that could burn), topography, and weather.

Variables that affect fire behavior include the rate of spread, intensity, fuel consumption, and fire type (such as
underbrush versus crown fire).

FIRM—Flood Insurance Rate Map
flash flood—A flood that occurs with little or no warning when water levels rise at an extremely fast rate
flood control system—A system of open channels, flood
control basins, storm drains, catch basins, culverts, low-flow diversion structures, pump stations, debris basins, detention basins, and spreading grounds developed to protect an area from flooding.

Flood Insurance Rate Map (FIRM)—The official maps on
which the Federal Emergency Management Agency
delineate the Special Flood Hazard Area.

Flood Insurance Study—A report published by the Federal Insurance and Mitigation Administration for a community in conjunction with the community’s Flood Insurance rate Map.

The study contains such background data as the base flood discharges and water surface elevations that were used to prepare the FIRM. In most cases, a community FIRM with
detailed mapping will have a corresponding flood insurance study.
floodplain—The land area along the sides of a river that becomes inundated with water during a flood.
flood—The inundation of normally dry land resulting from the rising and overflowing of a body of water.
floodway—Floodways are areas within a floodplain that are reserved for the purpose of conveying flood discharge
without increasing the base flood elevation more than 1 foot.

Generally speaking, no development is allowed in floodways, as any structures located there would block the flow of floodwaters.

FMA—Flood Mitigation Assistance grant program
freeboard—The margin of safety added to the base flood
elevation.
frequency—How often a hazard of specific magnitude,
duration, and/or extent is expected to occur on average.

Statistically, a hazard with a 100-year frequency is expected to occur about once every 100 years on average and has a 1 percent chance of occurring any given year. Frequency
reliability varies depending on the type of hazard considered.

City of Concord Hazard Mitigation Plan Definitions and Acronyms xv
geographic information system (GIS)—A computer
software application that relates data regarding physical and other features on the earth to a database for mapping and analysis.
g—Gravity (%g, percent acceleration force of gravity)
GIS—Geographic Information System
goal—A general guideline that explains what is to be
achieved. Goals are usually broad-based, long-term, policy- type statements and represent global visions. Goals help define the benefits that a plan is trying to achieve. The success of a hazard mitigation plan is measured by the
degree to which its goals have been met (that is, by the actual benefits in terms of actual hazard mitigation).
greenhouse gases—Methane, nitrous oxide and other
gases that trap heat and warm the Earth, as a greenhouse traps heat from the sun.
ground shaking—The result of rapid ground acceleration
caused by seismic waves passing beneath buildings, roads, and other structures.

Hazard Mitigation Grant Program (HMGP): Authorized
under Section 202 of the Robert T. Stafford Disaster Relief and Emergency Assistance Act, the HMGP is administered
by FEMA and provides grants to states, tribes, and local governments to implement hazard mitigation actions after a major disaster declaration. The purpose of the program is to reduce the loss of life and property due to disasters and to enable mitigation activities to be implemented as a
community recovers from a disaster
hazard—A source of potential danger or adverse condition that could harm people and/or cause property damage.
hazardous material—A substance or combination of
substances (biological, chemical, radiological, and/or
physical) that, because of its quantity, concentration, or physical, chemical or infectious characteristics, has the potential to cause harm to humans, animals, or the
environment, either by itself or through interaction with other factors.

Hazards U.S. Loss Estimation Program (Hazus)—A GIS-
based program used to support the development of risk
assessments as required under the DMA. The Hazus
software program assesses risk in a quantitative manner to estimate damage and losses associated with natural
hazards.

Hazus—Hazards, United States
high-hazard dam—Dams that can cause loss of human life
from the failure or improper operation of the dam.

HMGP—Hazard Mitigation Grant program
hydrology—Hydrology is the analysis of waters of the earth.

For example, a flood discharge estimate is developed by conducting a hydrologic study.
hypocenter—The region underground where an
earthquake’s energy originates
IBC—International Building Code
influenza—A viral infection that attacks the respiratory system; commonly called flu.
intensity—The measure of the effects of a hazard.
interface area—An area susceptible to wildfires and where wildland vegetation and urban or suburban development
occur together. An example would be smaller urban areas and dispersed rural housing in forested areas.
inventory—The assets identified in a study region.

Inventories include assets that could be lost when a disaster occurs, and community resources are at risk. Assets include people, buildings, transportation, and other valued
community resources.
landslide—The movement of masses of loosened rock and
soil down a hillside or slope. Slope failures occur when the strength of the soils forming the slope is exceeded by the pressure, such as weight or saturation, acting upon them. lightning—Lightning is an electrical discharge resulting from the buildup of positive and negative charges within a
thunderstorm. When the buildup becomes strong enough,
lightning appears as a “bolt,” usually within or between clouds and the ground. A bolt of lightning instantaneously reaches temperatures approaching 50,000ºF. The rapid
heating and cooling of air near lightning causes thunder.

Lightning is a major threat during thunderstorms. In the United States, 75 to 100 Americans are struck and killed by lightning each year (see
http://www.fema.gov/hazard/thunderstorms/thunder.shtm). liquefaction—Loosely packed, water-logged sediments
losing their strength in response to strong shaking, causing major damage during earthquakes.
local government—Any county, municipality, city, town,
township, public authority, school district, special district, intrastate district, council of governments (regardless of whether the council of governments is incorporated as a nonprofit corporation under State law), regional or interstate government entity, or agency or instrumentality of a local government; any Indian tribe or authorized tribal
organization, or Alaska Native village or organization; and any rural community, unincorporated town or village, or other public entity.
magnitude—The measure of the strength of an earthquake. mass movement: A collective term for landslides, debris flows, and lahars.
mitigation actions—Specific actions to achieve goals and objectives that minimize the effects from a disaster and reduce the loss of life and property.
mitigation—A preventive action taken in advance of an
event to reduce or eliminate risk to life or property.

Mw—Moment Magnitude Scale
NASA—National Aeronautics and Space Administration
NCEI—National Centers for Environmental Information
NEHRP—National Earthquake Hazard Reduction Program
NFIP—National Flood Insurance Program

City of Concord Hazard Mitigation Plan Definitions and Acronyms xvi
NIMS—National Incident Management System
NOAA—National Oceanic and Atmospheric Administration
NWS—National Weather Service
objective—For the purposes of this plan, an objective is defined as a short-term aim that, when combined with other objectives, forms a strategy or course of action to meet a goal. Unlike goals, objectives are specific and measurable. pandemic—An epidemic of infectious disease that has
spread through human populations across a large region, multiple continents, or worldwide.
peak ground acceleration (PGA)—A measure of the
highest amplitude of ground shaking that accompanies an earthquake, based on a percentage of the force of gravity.

PGA—Peak Ground Acceleration
ppm—Part per million
preparedness—Actions that strengthen the capability of
government, people, and communities to respond to
disasters.
presidential disaster declaration (same as federal
disaster declaration)—These declarations are typically
made for events that cause more damage than state and
local governments and resources can handle without federal government assistance. Generally, no specific dollar loss threshold has been established for such declarations. A presidential disaster declaration puts into motion long-term federal recovery programs, some of which are matched by state programs, designed to help disaster victims,
businesses, and public entities.
probability of occurrence—A statistical measure or
estimate of the likelihood that a hazard will occur. This probability is generally based on past hazard events in the area and a forecast of events that could occur in the future.

A probability factor based on yearly values of occurrence is used to estimate probability of occurrence.
recurrence interval —The recurrence interval (sometimes called the return period) is based on the probability that the given event will be equaled or exceeded in any given year. residual risk—The risk that remains after controls are
accounted for.
return period—The average number of years between
occurrences of a hazard (equal to the inverse of the annual likelihood of occurrence).
riparian area—The area along the banks of a natural
watercourse.
risk assessment—The process of measuring potential loss of life, personal injury, economic injury, and property damage resulting from hazards. This process assesses the vulnerability of people, buildings, and infrastructure to hazards
risk ranking—Process to score and rank hazards based on the probability that they will occur and the impact they will have if they do.
risk—The estimated impact that a hazard would have on
people, services, facilities, and structures in a community.

Risk measures the likelihood of a hazard occurring and
resulting in an adverse condition that causes injury or damage. Risk is often expressed in relative terms such as a high, moderate, or low likelihood of sustaining damage
above a particular threshold due to occurrence of a specific type of hazard. Risk also can be expressed in terms of
potential monetary losses associated with the intensity of the hazard.
riverine—Of or produced by a river. Riverine floodplains have readily identifiable channels.

Robert T. Stafford Act—The statutory authority for most federal disaster response activities, especially as they pertain to FEMA and its programs (Robert T. Stafford
Disaster Relief and Emergency Assistance Act, Public Law 100-107). Signed into law November 23, 1988; amended by the Disaster Relief Act of 1974 (Public Law 93-288).

SEMS—Standardized Emergency Management System
SFHA—Special Flood Hazard Area
significant-hazard dam—Dams that can cause economic
loss, environmental damage, or disruption of lifeline facilities, or can impact other concerns, but not necessarily loss of life. special flood hazard area—The base floodplain delineated on a Flood Insurance Rate Map. The SFHA is mapped as a
Zone A in riverine situations and zone V in coastal situations.

The SFHA may or may not encompass all of a community’s
flood problems
stakeholder—Business leaders, civic groups, academia,
non-profit organizations, major employers, managers of
critical facilities, farmers, developers, special purpose districts, and others whose actions could impact hazard mitigation.
steep slope—Different communities and agencies define it differently, depending on what it is being applied to, but generally a steep slope is a slope in which the percent slope equals or exceeds 25%. For this study, steep slope is
defined as slopes greater than 33%.
surface fault rupture—An offset of the ground surface
when fault rupture extends to the Earth’s surface.
technological hazards—Hazards from accidents
associated with human activities such as the manufacture, transportation, storage and use of hazardous materials. terrorism—The unlawful use or threatened use of force or violence against people or property with the intention of intimidating or coercing societies or governments. Terrorism is either foreign or domestic, depending on the origin, base, and objectives of the terrorist or organization.
transportation incident—A major incident related to a
means of transportation such air, rail or highway travel resulting in death, serious injury, or extensive property loss or damage.

USDA—U.S. Department of Agriculture
USDM—U.S. Drought Monitor

City of Concord Hazard Mitigation Plan Definitions and Acronyms xvii
USGS—U.S. Geological Survey
vector—An organism (such as an insect or rodent) that
transmits pathogens that cause disease
vector-borne illness—Diseases transmitted to people from insects and other animals. These include, but are not limited to, Hanta Virus, Plague, Tularemia, Lyme Disease, West
Nile Virus and the Zika Virus.
vulnerability—Assessment of how exposed or susceptible
an asset is to damage. Vulnerability depends on an asset’s construction, contents, and the economic value of its
functions.
watershed—An area that drains downgradient from areas of higher land to areas of lower land to the lowest point. weapons of mass destruction—Chemical, biological,
radiological, nuclear, and explosive weapons associated with terrorism.
wildfire—Fires that result in uncontrolled destruction of forests, brush, field crops, grasslands, and real and personal property in non-urban areas. Because of their distance from firefighting resources, they can be difficult to contain and can cause a great deal of destruction.

WMD—Weapon of mass destruction
zoning ordinance—Ordinance that designates allowable
land use and intensities for a local jurisdiction.

xviii

EXECUTIVE SUMMARY
Hazard mitigation is the use of long-term and short-term policies, programs, projects, and other activities to alleviate the death, injury, and property damage that can result from a disaster. The City of Concord has developed a hazard mitigation plan to reduce risks from disasters to the people, property, economy and environment within the city. The plan complies with federal and state hazard mitigation planning requirements to establish eligibility for funding under Federal Emergency Management Agency (FEMA) grant programs.

UPDATING THE CITY OF CONCORD PLAN
The City of Concord Hazard Mitigation Plan is the first single-jurisdiction hazard mitigation plan for the City, meeting federal requirements for regular review and update of hazard mitigation plans. Previously, the City of Concord participated in multi-jurisdictional hazard mitigation plans as a municipal planning partner. The City was included in the 2018 and 2011 Contra Costa County Hazard Mitigation Plans and was initially part of a 2005 regional planning effort sponsored by the Association of Bay Area Governments. The 2023 update includes a number of significant changes and enhancements for the City of Concord:
• An enhanced risk assessment
• Updated mission, goals and objectives
• Updated and enhanced public outreach
• An enhanced definition of critical facilities.

The development of this plan was funded by the City of Concord and co-managed by the Office of Emergency Services within the City of Concord Police Department and the City’s Community Development Department.

PLAN DEVELOPMENT APPROACH
A core planning team was assembled to facilitate the update of this plan, consisting of City staff and a contract consultant. An 18-member steering committee was assembled to oversee the plan update, consisting of both governmental and non-governmental stakeholders within the planning area, which was defined as the incorporated area of the City of Concord. Coordination with other local, state, and federal agencies involved in hazard mitigation occurred throughout the plan update process. The planning team and Steering Committee reviewed the Contra Costa County hazard mitigation plan, the California statewide hazard mitigation plan, and existing programs that may support hazard mitigation actions.

The planning team implemented a multi-media public involvement strategy that was approved by the Steering Committee. The strategy included participation at popular community events to make the public aware of the hazard mitigation plan update. Public outreach efforts included a hazard mitigation survey, a project website, the use of social

City of Concord Hazard Mitigation Plan Executive Summary xix
media (Facebook, Twitter and Nextdoor), announcements in the City of Concord e-newsletter, CERT outreach, and multiple press releases.

Based on the review of existing plans and programs, the input received through the public involvement strategy, the direction of the Steering Committee, and the findings of a new, detailed risk assessment performed for this update, the planning team assembled a document that meets federal hazard mitigation planning requirements. Once pre- adoption approval of the document has been granted by the California Governor’s Office of Emergency Services and FEMA Region 9, the final adoption phase will begin. The City of Concord City Council will adopt the updated plan.

RISK ASSESSMENT
Risk assessment is the process of measuring the potential loss of life resulting from hazards, as well as personal injury, economic injury and property damage, in order to determine the vulnerability of people, buildings, and infrastructure to hazard events. For this update, risk assessment models for natural hazards were enhanced with new data and technologies that have become available since 2018. The Steering Committee used the risk assessment to rank risk from natural hazards and to gauge the potential impacts of each natural hazard of concern in the planning area.

Human-caused hazards were also included in the risk assessment; however, risk was not ranked for these hazards.

Each hazard of concern assessed includes discussion of the following:
• Hazard identification and profile
• Assessment of the impact of hazards on physical, social, and economic assets • Identification of particular areas of vulnerability
• Estimates of the cost of potential damage, where applicable.

RISK RANKING
Based on the risk assessment, natural hazards were ranked for the risk they pose to the overall planning area, as shown in Figure ES-1.

Figure ES-1. Hazard Risk Rating
Earthquake
48 Severe Weather
30 Flood
18 Landslide
18 Dam/Levee Failure
6 Drought
9 Wildfire
6 0
2 4
6 0 1 2 3 4 5 6 7 8Values shown are risk ratings. Larger circles indicate higher rating.

High Risk
Medium
Risk
Low Risk

City of Concord Hazard Mitigation Plan Executive Summary xx

MISSION STATEMENT, GOALS, AND OBJECTIVES
The Steering Committee collaborated to review and completely revise the 2018 Contra Costa County hazard mitigation plan mission statement, goals, and objectives for this update for the City of Concord. The Steering Committee developed the following new mission statement for this update:

To join with our community to maintain and enhance a disaster-resistant City by reducing the potential for loss of life, property, and environmental damage from natural and human-caused disasters, while supporting economic recovery from those disasters.

Of five goals in the 2018 Contra Costa County hazard mitigation plan, three are revised and two are replaced for the City of Concord Hazard Mitigation Plan:

1. Minimize life, loss, and injuries.

2. Minimize damage to structures, property, equipment, the environment, and natural and cultural resources from hazards and climate change.

3. Improve emergency management effectiveness.

4. Ensure continuity of government operations.

5. Embed equity in emergency management plans.

The 2018 Contra Costa County objectives were carried into the City of Concord plan with slight modifications. Each selected objective meets multiple goals, serving as a stand-alone measurement of the effectiveness of a mitigation action, rather than as a subset of a goal. The objectives also are used to help establish priorities. The objectives are as follows:

1. Increase resilience of infrastructure and critical facilities.

2. Sustain reliable local emergency operations and facilities during and after a disaster.

3. Inform the public, in particular socially vulnerable communities, about the risk from hazards of concern, and increase awareness, preparation, mitigation, response, and recovery activities to promote public safety.

4. Minimize the impacts of known hazards on current land uses by providing incentives for hazard mitigation.

5. Prevent or discourage new development in hazardous areas or ensure that, if building occurs in high-risk areas, it is done in a way to minimize risk.

6. At the local government level, continually improve understanding of the location and potential impacts of hazards, using the best available data and science.

7. Encourage all development to meet applicable standards for life safety.

8. Monitor plan progress annually to integrate the local hazard mitigation plan with the results of disaster- and hazard-specific planning efforts.

9. Promote development and use of floodplain management best practices through programs such as FEMA’s Community Rating System.

10. Provide or improve flood protection with flood control structures and drainage maintenance plans.

11. Enhance building codes and their enforcement where feasible, so that new construction can withstand the impacts of known hazards and to lessen the impact of development on the environment’s ability to absorb the impact of natural hazards.

12. Consider the impacts of known hazards in planning mechanisms that address current and future land uses within the planning area.

City of Concord Hazard Mitigation Plan Executive Summary xxi

13. Eliminate or minimize disruption of local government operations caused by known hazards.

14. Consider open space land uses within identified high-hazard risk zones.

15. Retrofit, acquire, or relocate identified high-risk structures, including those known to experience repetitive losses.

16. Establish a partnership among appropriate levels of government and the business community to improve and implement methods to protect property.

17. Encourage hazard mitigation measures that promote and enhance natural processes and minimize adverse impacts on the ecosystem.

18. Promote and implement hazard mitigation plans and projects that are consistent with state, regional, and local climate action and adaptation goals, policies, and programs.

MITIGATION ACTION PLAN
Mitigation actions presented in this update are designed to reduce or eliminate losses resulting from hazard events.

The updated process resulted in the identification of 23 mitigation actions to be led by 6 City departments. Each action was given a priority rating for implementation and a separate priority rating for seeking grant funding. Table ES-1 summarizes the number of actions with each combination of implementation and grant funding priorities. Many of these actions are within the current capabilities of the City of Concord, resulting in high implementation priority over the next five years with no need for grant funding; however, if grant funding is available, City funds could be reallocated to other projects. Table ES-2 lists the mitigation actions with high implementation priority and no need for grant funding.

Table ES-1. Number of Recommended Mitigation Actions by Priority High Grant Funding Priority Medium Grant Funding
Priority Grant Funding Not Needed
High Implementation Priority 10 actions 5 actions 8 actions Medium Implementation
Priority 1 action none none

IMPLEMENTATION AND MAINTENANCE
Plan implementation will occur over the next five years as City departments begin to implement the actions identified in this plan. Full implementation of the recommendations of this plan will require time and resources. The measure of the plan’s success will be its ability to adapt to changing conditions. The City of Concord assumes responsibility for adopting the recommendations of this plan and committing resources toward implementation. The framework established by this plan prioritizes actions whose benefits exceed their cost. The planning team and Steering Committee developed this plan with extensive public input, and public support of the actions identified in this plan will help ensure the plan’s success.

The Steering Committee developed a plan maintenance strategy that includes annual progress reporting, a strategy for continued public involvement, a commitment to plan integration with other relevant plans and programs, and continued oversight from a plan maintenance steering committee.

City of Concord Hazard Mitigation Plan Executive Summary xxii
Table ES-2. High Implementation Priority Mitigation Actions with No Need for Grant Funding Action
# Action Description Lead Agency
2 Integrate the hazard mitigation plan into other plans, ordinances and programs that dictate land use decisions in the community, including the Development Code, the General Plan, and other programs.

Planning and
Housing Division
3 Actively participate in the plan maintenance protocols outlined in this hazard mitigation plan.

Office of Emergency
Services and
Community
Development
4 Continue to maintain good standing and compliance under the NFIP [National Flood Insurance Program] through the implementation of floodplain management programs that, at a minimum, meet the NFIP requirements:
• Enforce the flood damage prevention ordinance.
• Participate in floodplain identification and mapping updates. • Provide public assistance/information on floodplain requirements and impacts.

Community
Development
5 Galindo and Mt. Diablo Creek Drainage Improvements – Detention Basin at Ygnacio Valley Road and Pine Hollow Road.

Engineering
7 Develop a continuity of operations plan Office of Emergency Services
10 Identify an alternate Emergency Operations Center in Concord Office of Emergency Services
11 Adopt the 2022 California Existing Building Code for the design of voluntary or mandatory soft-story building retrofits
Planning and
Housing Division
13 Commission new or use existing local data to identify language access disparities that may impact emergency communication with limited English proficiency community members.

Use the data to improve communication plans, identify gaps in preparedness, and develop a comprehensive strategy for incorporating language access considerations into all steps of the City’s emergency management plans.

Office of Emergency
Services
14 Market Street Utility Undergrounding to reduce risk to utility lines from severe weather events (Capital Improvement Project #2628)
Engineering
15 Stormwater Green Infrastructure Pilot Project to install bio-retention facilities to mitigate drought impacts (Capital Improvement Project #2442)
Engineering
16 Emergency Operations Center updates to current emergency activation requirements (Capital Improvement Project #2473)
Information
Technology
17 Commercial Circle Storm Drain: Install new storm drain infrastructure to mitigate localized flooding from Mount Diablo Creek. (Capital Improvement Project #2494) Engineering
18 Stormwater green infrastructure: Install bioretention and capture devices to capture and reuse storm water at the following locations:
• Hillcrest Park – Regional (Capital Improvement Project #2512) • Iron Horse Park (Capital Improvement Project #2515)
• BART Cooperative (between Oak Grove Road and the BART Maintenance Yard) (Capital Improvement Project #2629)
• Concord Logo/Caltrans (intersection of Market Street and Clayton Road) (Capital Improvement Project #2631)
• CSU Campus (Capital Improvement Project #2636)
Engineering
19 Police Department generator and transfer switch replacement to reduce greenhouse gas emissions (Capital Improvement Project #2653)
Public Works
20 Blenheim Way: increase capacity of storm drain (Capital Improvement Project #2664) Engineering

City of Concord Hazard Mitigation Plan Executive Summary xxiii
Action
# Action Description Lead Agency
21 Citywide battery backup installation (Capital Improvement Project #2665) Community Development
22 La Vista Avenue/Joan Avenue storm drain design and construction to address localized flooding (Capital Improvement Project #ENG-23-036)
Engineering
23 Substantial Damage Response/Management Plan Public Works

City of Concord Hazard Mitigation Plan
PART 1—PLANNING PROCESS AND

COMMUNITY PROFILE

1-1

1. INTRODUCTION TO HAZARD MITIGATION PLANNING

1.1 WHY PREPARE THIS PLAN?

1.1.1 The Big Picture
Hazard mitigation is defined as any action taken to reduce or alleviate the loss of life, personal injury, and property damage that can result from a disaster. It involves long- and short-term actions implemented before, during and after disasters. Hazard mitigation activities include planning efforts, policy changes, programs, studies, improvement projects, and other steps to reduce the impacts of hazards.

The federal Disaster Mitigation Act (DMA) of 2000 emphasizes planning for disasters before they occur. The DMA requires state and local governments to develop hazard mitigation plans as a condition for federal disaster grant assistance. Regulations developed to fulfill the DMA’s requirements are included in Title 44 of the Code of Federal Regulations (44 CFR).

The responsibility for hazard mitigation lies with many, including private property owners, commercial interests, and local, state and federal governments. The DMA encourages cooperation among state and local authorities in pre- disaster planning. The planning network called for by the DMA helps local governments to articulate accurate needs for mitigation, resulting in faster allocation of funding and more cost-effective risk-reduction projects.

The DMA also promotes sustainability in hazard mitigation. To be sustainable, hazard mitigation needs to incorporate sound management of natural resources and address hazards and mitigation in the largest possible social and economic context.

1.1.2 Purposes for Planning
The City of Concord prepared this DMA-compliant hazard mitigation plan to identify resources, information, and strategies for reducing risk from natural hazards. Elements and strategies in the plan were selected because they meet a program requirement and the intent of the City and its residents to mitigate hazards. The plan will help guide mitigation activities throughout the planning area. It was developed to meet the following needs:
• Meet or exceed program requirements specified under the DMA • Enable the City of Concord to apply for federal grant funding to reduce hazard risk through mitigation • Fulfill state and federal requirements for hazard mitigation planning • Create a risk assessment that focuses on the hazards of concern in Concord • Coordinate existing plans and programs so that high-priority projects to mitigate potential disaster impacts are funded and implemented

City of Concord Hazard Mitigation Plan Introduction to Hazard Mitigation Planning 1-2
• Meet the planning requirements of the Federal Emergency Management Agency’s (FEMA’s) Community Rating System (CRS), allowing the City of Concord to maintain its CRS classification.

1.2 WHO WILL BENEFIT FROM THIS PLAN?
All residents and businesses of the City of Concord are the ultimate beneficiaries of this hazard mitigation plan. The plan reduces risk for those who live in, work in, and visit the City of Concord. It provides a viable planning framework for all foreseeable natural hazards. Participation in development of the plan by key stakeholders helped ensure that outcomes will be mutually beneficial. The plan’s goals and recommendations can lay groundwork for the development and implementation of local mitigation activities and partnerships.

1.3 CONTENTS OF THIS PLAN
This hazard mitigation plan is organized into three primary parts:
• Part 1—Planning Process and Community Profile
• Part 2—Risk Assessment
• Part 3—Mitigation Strategy.

Each part includes elements required under federal guidelines. DMA compliance requirements are cited at the beginning of subsections as appropriate to illustrate compliance. Appendices provided at the end of the plan include information or explanations to support the main content of the plan.

2-1

2. PLAN UPDATE—WHAT HAS CHANGED

2.1 THE PREVIOUS PLAN
This is the first single-jurisdiction hazard mitigation plan for the City of Concord. Previously, the City participated in multi-jurisdictional hazard mitigation plans as a planning partner. The City was included in the 2018 and 2011 Contra Costa County Hazard Mitigation Plans and was part a 2005 regional planning effort sponsored by the Association of Bay Area Governments.

The City of Concord has been covered by Contra Costa County’s 2018 multi-jurisdiction hazard mitigation plan since its adoption. Concord was one of 34 municipalities and special purpose district that participated as planning partners in the Contra Costa County plan. Based on its evaluations for that plan, the City of Concord identified risks associated with local hazards of concern as follows:
• High-risk hazards—earthquake
• Medium-risk hazards—severe weather, flood, landslide
• Low-risk hazards—dam and levee failure, drought, wildfire To address the risks associated with these hazards, the City developed recommendations for 18 mitigation actions, of which 10 were identified as high priority for implementation, seven were identified as medium priority, and one was identified as low priority. The Contra Costa County plan also included seven mitigation actions adopted by all participating planning partners.

2.2 WHY UPDATE?

2.2.1 Federal Eligibility
Title 44 of the Code of Federal Regulations (44 CFR) stipulates that hazard mitigation plans must present a schedule for being monitored, evaluated, and updated. This provides an opportunity to reevaluate recommendations, monitor the impacts of actions that have been accomplished, and determine if there is a need to change the focus of mitigation strategies. A jurisdiction covered by a plan that has expired is not able to pursue federal funding for which a current hazard mitigation plan is a prerequisite.

2.2.2 Changes in Development
Hazard mitigation plan updates must reflect development changes in the planning area since approval of the previous plan (44 CFR Section 201.6(d)(3)). The update must describe development changes in hazard-prone areas that increased or decreased vulnerability. If no development changes impacted the jurisdiction’s overall vulnerability, plan

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-2
updates may validate the information in the previously approved plan. This requirement ensures that the mitigation strategy continues to address the risk and vulnerability of existing and potential development and takes into consideration possible future conditions that could impact vulnerability.

Although the City of Concord’s population has declined slightly since adoption of the 2018 County hazard mitigation plan (California Department of Finance 2021, California Department of Finance 2022), the City has seen ongoing new development. Over 200 new development permits were issued in 2017 through 2021, most of them for new single- family residential homes. This hazard mitigation plan update assumes that some new development occurred in hazard areas. All such new development would have been regulated pursuant to local programs and codes. The City has adopted a general plan that governs land-use decisions and policy-making, as well as a building code and specialty ordinances based on state and federal mandates. Therefore, it is assumed that hazard vulnerability did not measurably increase even if exposure did. Any new development would have accounted for potential hazard impacts under codes and standards such as the International Building Code and flood damage prevention requirements of the National Flood Insurance Program (NFIP).

2.3 THE UPDATED PLAN—WHAT IS DIFFERENT?
The 2023 City of Concord Hazard Mitigation Plan includes a number of significant changes and enhancements from the previous hazard mitigation plan in which the City of Concord participated:
• An enhanced risk assessment
• Updated mission, goals and objectives
• Updated and enhanced public outreach
• An enhanced definition of critical facilities.

Table 2-1 indicates the major changes between this hazard mitigation plan for the City of Concord and the 2018 Contra Costa County multi-jurisdiction hazard mitigation plan.

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-3
Table 2-1. Plan Changes Crosswalk
44 CFR Requirement
Previous Plan (Contra Costa County,
2018) Updated Plan
§201.6(b): In order to develop a more
comprehensive approach to reducing
the effects of natural disasters, the
planning process shall include:
(1) An opportunity for the
public to comment on the plan
during the drafting stage and prior
to plan approval;
(2) An opportunity for
neighboring communities, local
and regional agencies involved in
hazard mitigation activities, and
agencies that have the authority
to regulate development, as well
as businesses, academia and other
private and non-profit interests to
be involved in the planning
process; and
(3) Review and incorporation, if
appropriate, of existing plans,
studies, reports, and technical
information.
[Concord participated in the
Countywide multijurisdictional plan.]
Building upon the success of the
Countywide multijurisdictional 2011
plan, the 2018 planning effort
deployed the same public
engagement methodology.

Enhancements included:

Utilization of social media
Web deployed survey
Enhanced press coverage
As with the 2011 plan, the 2018
planning process identified key
stakeholders and coordinated with
them throughout the process. A
comprehensive review of relevant
plans and programs was performed
by the planning team
The plan development process was similar to
the 2018 Contra Costa County
multijurisdictional plan which Concord
participated in. Chapters 1, 2, and 3 outline
the planning process for this stand-alone
plan.

This update was facilitated through a
committee-based approach. Two committees
played significant roles in the process:

Core Planning Team—Consisting of
department leads from the City and
technical consultant. Made all milestone
decisions on plan process and content.

Milestone decisions were vetted, validated,
and overseen by the Steering Committee
made up of city staff and outside
stakeholders. Meetings were open to the
public.

Both committees reviewed existing plans and
programs that could support or enhance the
outcomes from this plan and identified and
participated in a robust public engagement
strategy.

Public outreach and engagement included a
survey, website information, and outreach to
various community groups throughout the
planning process, allowing for input and
comments from the public.

Plans were reviewed during the development
of this plan. City plans – Emergency
Operations and Capital Improvement – were
used in the consideration of risks to the City
and possible action items that would be useful
for mitigation efforts.
§201.6(c)(2): The plan shall include a
risk assessment that provides the
factual basis for activities proposed
in the strategy to reduce losses from
identified hazards. Local risk
assessments must provide sufficient
information to enable the jurisdiction
to identify and prioritize appropriate
mitigation actions to reduce losses
from identified hazards.

Using the same methodology as the
previous county plan, the risk
assessment was expanded to include
a profile of the tsunami hazard. The
risk assessment included a detailed
profile of potential impacts of
climate change on the assessed
hazards of concern. A qualitative
profile of non-natural hazards was
included. These hazards were
profiled only and not fully assessed
or ranked as with the natural
hazards.

Part 2 (Chapters 7 – 17) presents a risk
assessment of the hazards of concern:
earthquake, severe weather, flood, landslide,
dam and levee failure, drought, and wildfire;
human-caused hazards; and public health
hazards. These hazards are profiled as they
impact the Concord planning area. Including a
qualitative assessment of human caused
hazards and health hazards provides a more
complete picture of the hazards facing the
planning area.

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-4
44 CFR Requirement
Previous Plan (Contra Costa County,
2018) Updated Plan
§201.6(c)(2)(i): [The risk assessment
shall include a] description of the …
location and extent of all natural
hazards that can affect the
jurisdiction. The plan shall include
information on previous occurrences
of hazard events and on the
probability of future hazard events.

The plan presented a risk
assessment of each hazard of
concern. Each chapter included the
following components:

Hazard profile, including maps of
extent and location, historical
occurrences, frequency, severity
and warning time.

Secondary hazards
Exposure of people, property, critical
facilities and environment
Vulnerability of people, property,
critical facilities and environment.

Future trends in development
Scenarios
Issues
Climate change was addressed as a
stand-alone chapter.

Part 2 presents a risk assessment of each
hazard of concern. Each chapter includes the
following components:

Hazard profile, including maps of extent and
location, historical occurrences, frequency,
severity, and warning time
Secondary hazards
Exposure of people, property, critical facilities
and environment
Vulnerability of people, property, critical
facilities and environment
Future trends in development
Scenarios
Issues
The hazards are compared to one another via
a risk ranking methodology described in
Chapter 17.
§201.6(c)(2)(ii): [The risk assessment
shall include a] description of the
jurisdiction’s vulnerability to the
hazards described in paragraph
(c)(2)(i). This description shall include
an overall summary of each hazard
and its impact on the community
Hazus version 3.2 was utilized for all
risk analyses. Vulnerability for the
tsunami hazard was not modeled
using Hazus because version 4.0 had
not yet been released at the time of
the risk assessment.

Vulnerability was assessed for all hazards of
concern. The Hazus computer model (version

4.2) was used for dam failure, earthquake and
flood hazards. Critical facilities and assets
were defined and inventoried using the Hazus
Comprehensive Data Management System
and other available datasets. Outputs were
generated for other hazards by applying an
estimated damage function to affected assets
when available. The asset inventory was
extracted from the Hazus model. Best
available data was used for all analyses.
§201.6(c)(2)(ii): [The risk assessment]
must also address National Flood
Insurance Program insured structures
that have been repetitively damaged
by floods
The plan included a CRS level of
detail repetitive loss area analysis
based on 2016 repetitive loss data
and the 2013 CRS Coordinators
Manual.

The description of the National Flood
Insurance Program and repetitive loss
discussion was enhanced to meet DMA and
CRS planning requirements. The update
includes a comprehensive analysis of
repetitive loss properties. For these
properties, the type of structure was
determined and causes of flooding were
cited, and the information was reflected on
maps. National Flood Insurance Program
capability is also assessed, as detailed in
Section 6.3.7.

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-5
44 CFR Requirement
Previous Plan (Contra Costa County,
2018) Updated Plan
§201.6(c)(2)(ii)(A): The plan should
describe vulnerability in terms of the
types and numbers of existing and
future buildings, infrastructure, and
critical facilities located in the
identified hazard area.

A complete inventory of the
numbers and types of buildings
exposed was generated for each
hazard of concern. The Steering
Committee defined “critical
facilities” for the planning area, and
these were inventoried by exposure.

Each hazard chapter provides a
discussion on future development
trends.

A complete inventory of the numbers and
types of buildings exposed was generated for
each hazard of concern. The steering
committee defined “critical facilities” as they
pertained to the planning area, and these
facilities were inventoried by exposure. Each
hazard chapter provides a discussion of
future development trends as they pertain to
the hazard.
§201.6(c)(2)(ii)(B): [The plan should
describe vulnerability in terms of an]
estimate of the potential dollar losses
to vulnerable structures identified in
paragraph (c)(2)(i)(A) and a
description of the methodology used
to prepare the estimate.

Loss estimates were generated for
all hazards of concern. These were
generated by Hazus for the
earthquake and flood hazards. For
the other hazards, loss estimates
were generated by applying a
regionally relevant damage function
to the exposed inventory. In all
cases, a damage function was
applied to an asset inventory. The
asset inventory was the same for all
hazards and was generated in Hazus.

Loss estimations were generated for all
hazards of concern. These were generated by
Hazus for the earthquake and flood hazards.

For the other hazards, loss estimates were
generated by applying a regionally relevant
damage function to the exposed inventory. In
all cases, a damage function was applied to
an asset inventory. The asset inventory was
the same for all hazards and was generated in
the Hazus model.
§201.6(c)(2)(ii)(C): [The plan should
describe vulnerability in terms of]
providing a general description of
land uses and development trends
within the community so that
mitigation options can be considered
in future land use decisions.

A look at the change in risk due to
new development over the
performance period of the plan was
performed for each hazard of
concern.

There is a discussion on future development
trends as they pertain to each hazard of
concern. This discussion looks predominantly
at the existing land use and the current
regulatory environment that dictates this land
use.
§201.6(c)(3): The plan shall include a
mitigation strategy that provides the
jurisdiction’s blueprint for reducing
the potential losses identified in the
risk assessment, based on existing
authorities, policies, programs and
resources, and its ability to expand
on and improve these existing tools.

The Steering Committee reviewed
and reconfirmed the guiding
principle, goals and objectives for
the plan. Each planning partner used
the progress reporting from the plan
maintenance and evaluated the
status of actions identified in the
2011 plan. Actions that were
completed or no longer considered
to be feasible were removed. The
rest of the actions were carried over
to the 2018 plan and in some cases,
new actions were added to the
action plan.

An initiative action plan was developed for
the City of Concord (Chapter 20) via a
facilitated process that includes:

Risk ranking
Capability assessment
Initiative alternative review
Initiative selection
Initiative prioritization
Initiative category analysis

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-6
44 CFR Requirement
Previous Plan (Contra Costa County,
2018) Updated Plan
§201.6(c)(3)(i): [The hazard
mitigation strategy shall include a]
description of mitigation goals to
reduce or avoid long-term
vulnerabilities to the identified
hazards.

The Steering Committee reviewed
and reconfirmed the guiding
principle, goals and objectives for
the plan with minor wording
changes.

Chapter 18 identifies a mission statement, 5
goals and 18 objectives. Objectives were
selected that meet multiple goals, and
mitigation actions were selected and
prioritized based on meeting multiple
objectives. All of these planning components
were new for this plan update and have been
reviewed and confirmed by the Steering
Committee
§201.6(c)(3)(ii): [The mitigation
strategy shall include a] section that
identifies and analyzes a
comprehensive range of specific
mitigation actions and projects being
considered to reduce the effects of
each hazard, with particular
emphasis on new and existing
buildings and infrastructure.

The mitigation catalog was reviewed
and updated by the Steering
Committee. Additional mitigation
actions were added for the tsunami
hazard, which was a new hazard
assessed for this plan update. The
catalog is included in the plan to
represent the comprehensive range
of alternatives considered by each
planning partner. The analysis of
mitigation actions was used in
jurisdictional annexes to the plan.

A hazard mitigation catalog was developed
through a facilitated process. This catalog
identifies actions that manipulate the hazard,
reduce exposure to the hazard, reduce
vulnerability, and increase mitigation
capability. The catalog further segregates
actions by scale of implementation. A table in
the action plan chapter analyzes each action
by mitigation type to illustrate the range of
actions selected.
§201.6(c)(3)(ii): [The mitigation
strategy] must also address the
jurisdiction’s participation in the
National Flood Insurance Program,
and continued compliance with the
program’s requirements, as
appropriate.

All municipal planning partners that
participate in the National Flood
Insurance Program identified an
action stating their commitment to
maintain compliance and good
standing under the program.

Communities that participate in the
Community Rating System identified
actions to maintain or enhance their
standing under the CRS.

The capability assessment in Section 5.3.7
includes an assessment of capabilities related
to NFIP requirements. The action plan in
Chapter 20 includes actions supporting
continued compliance and good standing
under the program.
§201.6(c)(3)(iii): [The mitigation
strategy shall describe] how the
actions identified in Section (c)(3)(ii)
will be prioritized, implemented, and
administered by the local jurisdiction.

Prioritization shall include a special
emphasis on the extent to which
benefits are maximized according to
a cost benefit review of the proposed
projects and their associated costs.

Each recommended action was
prioritized using a qualitative
methodology based on the
objectives the project will meet, the
timeline for completion, how the
project will be funded, the impact of
the project, the benefits of the
project and the costs of the project.

Each of the recommended actions is
prioritized using a qualitative methodology
that looked at the objectives the project will
meet, the timeline for completion, how the
project will be funded, the impact of the
project, the benefits of the project and the
costs of the project. This prioritization
scheme is detailed in Section 20.2.
§201.6(c)(4)(i): [The plan
maintenance process shall include a]
section describing the method and
schedule of monitoring, evaluating,
and updating the mitigation plan
within a five-year cycle.

The plan details a plan maintenance
strategy that involved a protocol for
annual progress reporting by all
planning partners. The strategy
identifies triggers for plan updates,
integration with other plans and
programs and a protocol for
continuing public involvement.

Chapter 21 includes a detailed plan
maintenance strategy centered on an annual
progress report via an automated platform
that will be maintained by the City over the 5-
year performance period of the plan.

City of Concord Hazard Mitigation Plan Plan Update—What Has Changed 2-7
44 CFR Requirement
Previous Plan (Contra Costa County,
2018) Updated Plan
§201.6(c)(4)(ii): [The plan shall
include a] process by which local
governments incorporate the
requirements of the mitigation plan
into other planning mechanisms such
as comprehensive or capital
improvement plans, when
appropriate.

The plan details recommendations
for incorporating the plan into other
planning mechanisms such as:

Comprehensive Plan
Emergency Operations Plan
Capital Improvement Programs
Municipal Code
Continuity of Operations Plan

A detailed plan maintenance strategy, found
in chapter 21, includes the following:

Annual review and progress reporting
Defined role for a steering committee
Plan update triggers
Plan incorporation guidelines
Strategy for continuing public involvement
Grant coordinating protocol
The plan will continue to review and
incorporate relevant elements from the plans
identified in the 2017.
§201.6(c)(4)(iii): [The plan
maintenance process shall include a]
discussion on how the community
will continue public participation in
the plan maintenance process.

The plan details a strategy for
continuing public involvement.

Chapter 21 details a comprehensive strategy
for continuing public involvement.
§201.6(c)(5): [The local hazard
mitigation plan shall include]
documentation that the plan has
been formally adopted by the
governing body of the jurisdiction
requesting approval of the plan (e.g.,
City Council, County Commission,
Tribal Council).

All planning partners that fully met
their “participation” requirements as
defined by the planning process
formally adopted the plan. Appendix
C of the plan presents the
resolutions of all planning partners
that adopted this plan.

Section 21.1 will include all formal adoption
and FEMA plan approval documentation once
adopted by the City.

3-1

3. PLAN DEVELOPMENT APPROACH

3.1 FORMATION OF THE PLANNING TEAM
The City of Concord hired Tetra Tech, Inc. to assist with development and implementation of the plan. The Tetra Tech project manager assumed the role of the lead planner, reporting directly to the City of Concord project manager.

A planning team was formed to lead the planning effort, made up of the following members:
• Trish Beirne, Emergency & Volunteer Services Manager, City of Concord • Bruce Davis, Senior Civil Engineer, City of Concord
• Kevin Marstall, Community Development Director, City of Concord • Jennifer Nylander, Administrative Coordinator, City of Concord • Carlton Thompson, Engineer, City of Concord
• Bart Spencer, Tetra Tech (project manager)
• Megan Brotherton, Tetra Tech (planner/public outreach discipline lead) • Nate Stueve, Tetra Tech (planner/profiling lead)
• Jake Poland, Tetra Tech (planner)
• Carol Baumann, Tetra Tech (risk assessment discipline lead) This planning team coordinated regularly during the course of this project to track plan development milestones and to identify meeting content for a steering committee established to help with development of the update.

3.2 DEFINING THE PLANNING AREA
The planning area consists of the incorporated area of the City of Concord. Relevant planning area characteristics are described in Chapter 4. The defined planning area is shown in Figure 3-1, including the boundaries of the City Council districts. In the risk assessments performed for this hazard mitigation plan, results are presented citywide as well as for each of the five districts.

UV242
UV4
UV4
§¨¦680
Treat Blvd
Clayton Rd
Willow Pass Rd
Kirker Pass RdMonument Blvd
Oak Grove Rd
Port Chicago Hwy
Cowell Rd
Galindo St
Concord Blvd
Ygnacio Valley Rd
Mallard
Reservoir
District 1
District 2
District 5
District 4
District 3
Concord

PLANNING AREA
Data Sources:

CIty of Concord
0 1 2
Miles
4 Freeway
Major Arterial
City Boundary
Park
WaterbodyStream
Figure 3-1

City of Concord Hazard Mitigation Plan Plan Development Approach 3-3

3.3 THE STEERING COMMITTEE
A steering committee was formed to oversee all phases of the plan. The members of this committee included key City of Concord staff, residents, and other stakeholders from within the planning area. The planning team assembled a list of candidates representing interests within the planning area that could have recommendations for the plan or be impacted by its recommendations. The team confirmed a committee of 18 members at the kickoff meeting. One alternate member was also named. Table 3-1 lists the Steering Committee members.

Table 3-1. Steering Committee Members
Name Title Department or Agency
Trish Beirne Emergency and Volunteer Services
Manager
City of Concord Police Department / Office of
Emergency Services
Jesse Crawford Maintenance Superintendent City of Concord Engineering Division Bruce Davis Senior Civil Engineer City of Concord Engineering Division Stephanie Gronlund Engineering Central Contra Costa Sanitary District Rick Kovar (Vice-Chair 1) Emergency Services Manager Contra Costa County Office of Emergency Services Mateika Martin Manager, Threat and Emergency
Management
John Muir Health
Kathryn Monroy Program Manager City of Concord Parks and Recreation Jill Mosley Principal Engineer Contra Costa Water District Jennifer Nylander Administrative Coordinator City of Concord Community Development Jennifer Ortega Community Relations Manager City of Concord Manager’s Office Bea Portillo (Vice-Chair 2) Emergency Planning Coordinator Contra Costa County Office of Emergency Services Ryan Pursley (Chair) Chief Building Official City of Concord Building Division Les Putnam Senior Public Safety Specialist PG&E
Jenny Schaeffer Programs Director Food Bank of Contra Costa & Solano Danny Scherer Logistics Manager Monument Crisis Center
Brian Snead Damage Prevention/Right of Way
Specialist PNR Bay Division
Kinder Morgan
Briana Taylor Northern CA Coastal Region American Red Cross Norman Wong Principal Planner BART
Natalie Manier (Alternate) For Briana Taylor American Red Cross

Leadership roles and ground rules were established during the Steering Committee’s initial meeting on October 11, 2022. The planning team facilitated each Steering Committee meeting, which addressed a set of objectives based on the work plan established for the planning process. The Steering Committee met three times from October 2022 through February 2023. Meeting agendas, meeting summaries and sign-in sheets are available for review upon request.

All Steering Committee meetings were open to the public, and agendas and meeting summaries were posted to the hazard mitigation plan website.

3.4 COORDINATION WITH STAKEHOLDERS AND OTHER AGENCIES
Opportunities for involvement in the planning process must be provided to neighboring communities, local and regional agencies involved in hazard mitigation, agencies with authority to regulate development, businesses,

City of Concord Hazard Mitigation Plan Plan Development Approach 3-4
academia, and other private and nonprofit interests (44 CFR, Section 201.6(b)(2)). This task was accomplished by the planning team as follows:
• Steering Committee Involvement—Agency representatives were invited to join the Steering Committee. • Agency Notification—City staff invited the following agencies to participate in the plan development process from the beginning; these agencies were kept apprised of plan development milestones by email, telephone calls, and personal contact:
➢ American Red Cross
➢ Bay Area Rapid Transit (BART)
➢ California Governor’s Office of Emergency Services (Cal OES) ➢ California Department of Water Resources (DWR)
➢ Central Contra Costa Sanitary District
➢ Contra Costa Water District
➢ Contra Costa County Office of Emergency Services
➢ East Bay Regional Parks District
➢ FEMA Region 9
➢ Food Bank of Contra Costa & Solano
➢ John Muir Health
➢ Kinder Morgan
➢ Monument Crisis Center
➢ National Oceanic and Atmospheric Administration (NOAA) ➢ Pacific Gas and Electric (PG&E)
➢ U.S. Geological Survey (USGS)
➢ Residents within Council Districts
➢ Community Emergency Response Team (CERT)
Some of these agencies supported the effort by attending meetings or providing feedback on issues. • Pre-Adoption Review—All the agencies listed above were provided an opportunity to review and comment on this plan during the public comment period, primarily through the hazard mitigation plan website. Each agency was sent an e-mail message informing them that draft portions of the plan were available for review.

In addition, the complete draft plan was sent to Cal OES and FEMA for a pre-adoption review to ensure program compliance.

Stakeholder contributions to the planning process included the following:
• FEMA Region 9 provided planning guidance and data from the National Flood Insurance Program • The U.S. Geological Survey provided ShakeMaps for earthquake analyses • Cal OES provided planning guidance and reviewed the draft and final versions of the plan

3.5 REVIEW OF EXISTING PROGRAMS
Hazard mitigation planning must include review and incorporation, if appropriate, of existing plans, studies, reports and technical information (44 CFR, Section 201.6(b)(3)). Chapter 4 of this plan provides a review of laws and ordinances in effect within the planning area that can affect hazard mitigation actions. In addition, the following programs can affect mitigation within the planning area:
• City of Concord 2030 General Plan
• Downtown Concord Specific Plan

City of Concord Hazard Mitigation Plan Plan Development Approach 3-5
• Housing Element 2014-2022
• Housing Element 2023-2031
• California Fire Code
• 2022 California Building Code
• California State Hazard Mitigation Forum
• City Capital Improvement Programs
• City Emergency Operations Plan
• Citywide Climate Action Plan
• Contra Costa County Climate Action Plan
• Contra Costa County General Plan
• Safety and Noise Element
• City Development Code
• City Zoning Ordinances
• City Floodplain Management Ordinance

3.6 PUBLIC INVOLVEMENT
Broad public participation in the planning process helps ensure that diverse points of view about the planning area’s needs are considered and addressed. The public must have opportunities to comment on disaster mitigation plans during the drafting stages and prior to plan approval (44 CFR, Section 201.6(b)(1)).

3.6.1 Strategy
The strategy for involving the public in this plan emphasized the following elements:
• Include members of the public on the Steering Committee. • Use a survey to determine if the public’s perception of risk and support of hazard mitigation has changed since the initial planning process.
• Attempt to reach as many planning area residents as possible through the following activities:
➢ Development of a public outreach plan, approved by the Steering Committee ➢ Attendance at advertised public outreach events and meetings with live interaction ➢ Development of a hazard mitigation plan webpage on the City website ➢ Use of social media, such as Nextdoor, Instagram, Facebook and Twitter ➢ Development and advertisement of a public survey posted on Survey Monkey to collect pertinent information from residents and the business community.

Stakeholders and the Steering Committee
Stakeholders are the individuals, departments, agencies and jurisdictions that have a vested interest in the recommendations of the hazard mitigation plan. The effort to include stakeholders in this process included

City of Concord Hazard Mitigation Plan Plan Development Approach 3-6
stakeholder participation on the Steering Committee. The following federal, state, regional, and local stakeholders also played a role in the planning process:
• Federal Agencies—FEMA Region 9 provided updated planning guidance, provided summary and detailed data for the City from the National Flood Insurance Program (including repetitive loss information), and conducted a plan review.
• State Agencies—Cal OES provided updated planning guidance and reviewed the draft and final versions of the plan update as part of their state hazard mitigation planning process required by the DMA.

Survey
A multi-lingual hazard mitigation plan survey (see Figure 3-2) was developed by the planning team with guidance from the Steering Committee. The survey was used to gauge preparedness for all hazards and the level of knowledge of tools and techniques that assist in reducing risk and loss from natural hazards. This survey was designed to help identify areas vulnerable to one or more hazards. The answers to its 19 questions helped guide the Steering Committee in determining planning goals, objectives and mitigation strategies. Surveys were distributed at public- outreach events, and a web-based version of the survey was made available on the hazard mitigation plan website. The complete survey and an analysis of its findings can be found in Appendix A.

Public Events
Planning team members and other volunteers attended public events to make the public aware of the update to the hazard mitigation plan and invite residents to take the public survey (see Figure 3-3 through Figure 3-6). Residents who attended the events were asked to complete the survey online or on a paper copy, and each was given an opportunity to provide comments for the Steering Committee. Local media outlets were informed of the events by City press releases.

The first event was at the Concord Holiday Tree Lighting Ceremony on December 2, 2022. The annual event draws hundreds of community members to the Todos Santos Plaza. Volunteers from CERT and the Concord Police Service Program provided emergency and disaster information and spoke with attendees about the plan update process and the public survey.

The Concord Senior Craft Fair was the second event the planning team and mitigation volunteers attended. This event on December 3, 2022, engaged seniors and other community members with hazard awareness information and opportunities to take the public survey.

Hazard Mitigation Plan Website
During the planning process, a webpage was created on the City of Concord website to introduce the hazard mitigation plan update and keep the public apprised of upcoming outreach events, meeting dates and times, public survey, and plan update process (see Figure 3-7). The website address is: https://www.cityofconcord.org/1034/Local- Hazard-Mitigation-Plan-LHMP.

The site’s address was publicized at all public meetings and in all social media releases. Information on the plan development process, the Steering Committee, the survey and drafts of the plan were made available to the public on the website throughout the process. The City of Concord intends to keep the webpage active after the plan’s completion to keep the public informed about successful mitigation projects and future plan updates.

City of Concord Hazard Mitigation Plan Plan Development Approach 3-7

Figure 3-2. Sample Page from Survey Distributed to the Public

City of Concord Hazard Mitigation Plan Plan Development Approach 3-8

Figure 3-3. Hazard Awareness Booth at the Concord Senior Center Craft Fair
Figure 3-4. Surveys Distributed at the Concord Senior Center Craft Fair

Figure 3-5. Hazard Mitigation Booth Volunteers at the
Concord Tree Lighting Ceremony
Figure 3-6. Surveys Distributed at the Concord Tree Lighting Ceremony

City of Concord Hazard Mitigation Plan Plan Development Approach 3-9

Figure 3-7. Hazard Mitigation Plan Webpage on the City of Concord Website

City of Concord Hazard Mitigation Plan Plan Development Approach 3-10
Story Map
An online “Story Map” was created (using the Esri StoryMap software) to communicate the variety and severity of hazards facing the City of Concord (see Figure 3-8). During the update process, the Story Map was released to the public and promoted through print and social media, the project website, and during public meetings. It includes risk assessment results for all relevant hazards and an interactive hazard mapping tool. The Story Map expanded the ways in which members of the public could interact with hazard data as the hazard mitigation plan update was underway.

Figure 3-8. Example Story Map Data Page
After completion of the hazard mitigation plan update, the City of Concord Story Map will continue to support visual and data-based communication about the range of hazards relevant in the city. The Story Map is available through the City’s website: Concord Hazard Mitigation Plan StoryMap

3.6.2 Public Involvement Results
The public involvement strategy used for the plan update introduced the concept of mitigation to the public and provided the Steering Committee with feedback to use in developing the plan. All residents of the planning area had opportunities to provide comment during all phases of the plan update process. Attendance and survey distribution at the public meetings are summarized in Table 3-2.

Table 3-2. Summary of Public Meetings and Events
Date Type of Event Number in Attendance
October 11, 2022 Concord Hazard Mitigation Plan Steering Committee Meeting #1 23 December 2, 2022 Hazard Mitigation Booth Volunteers at the Concord Tree Lighting Ceremony 5,000 December 3, 2022 Hazard Awareness Booth at the Concord Senior Center Craft Fair 300 December 13, 2022 Concord Hazard Mitigation Plan Steering Committee Meeting #2 18 February 14, 2023 Concord Hazard Mitigation Plan Steering Committee Meeting #3 20 Total 5,361

City of Concord Hazard Mitigation Plan Plan Development Approach 3-11
Survey Outreach
The survey was released in English, Spanish, Dari, Chinese, Vietnamese, and Tagalog. Completed surveys were received from 349 respondents, including 42 from languages other than English. Of these respondents, 72 percent have been affected by severe weather, nearly 66 percent have experienced an earthquake, and another 61 percent have been affected by drought. Survey results were shared with the Steering Committee. Detailed survey results are provided in Appendix A. Key results are as follows:
• Survey respondents ranked earthquake as the hazard of highest concern, followed closely by severe weather, flood, and drought.
• The majority of respondents believe that the best method to receive disaster information is by SMS/text, followed by the Contra Costa Community Warning System.
• 63 percent of respondents indicated that their households are somewhat prepared to survive without electricity or natural gas for five or more days; 11 percent said they are very prepared and 26 percent said they are not at all prepared.
• Over 43 percent of respondents indicated that when they moved into their home, they considered the impact a disaster could have on their home.
• Nearly 48 percent of the respondents indicated that they do not know if their home is located in a mapped hazard area.
• Most respondents stated that incentives would entice them to spend money to mitigate their property. The two most popular incentives were insurance premium discounts and free local government technical assistance.

Survey results included more than 100 respondents who provided their email address to receive additional information regarding emergency preparedness in the Concord area. Concord’s Office of Emergency Services will follow up with each of these respondents.

Public Comments on the Draft Plan
A formal 14-day public comment period was initiated on February 13, 2023. During this comment period, the public was asked to review the proposed draft of the hazard mitigation plan and provide comments to the Planning Team by February 27, 2023. The public comment period was advertised on the hazard mitigation plan website as well as a press release to all media outlets and social media blast through outlets used by the City.

The Planning Team received four comments during the public comment period. Those that were deemed relevant to the overall plan by the planning team were incorporated into the final submittal draft of the plan. Most of the comments fell outside the scope of this plan update and were noted by the planning team for consideration under other emergency management programs of the City. Copies of the comments were retained by the planning team and are available upon request.

3.7 PLAN DEVELOPMENT CHRONOLOGY/MILESTONES
Table 3-3 summarizes important milestones in the plan update process.

City of Concord Hazard Mitigation Plan Plan Development Approach 3-12
Table 3-3. Plan Development Chronology/Milestones
Date Event Description Attendance
2022
7/14 City releases a request for
proposals to update its
hazard mitigation plan
Secure contractor support to facilitate update of the City’s hazard mitigation plan
N/A
7/28 City Selects Tetra Tech as its
technical support Contractor
Technical support secured N/A
7/29 City executes contract with
Tetra Tech for technical
support of hazard mitigation
plan update
Notice to proceed N/A
9/14 Planning Team call #1 Planning process 8
9/27 Planning team call #2 Planning process 8
10/11 Planning Team call #3 Planning process 8
10/11 1st Steering Committee
Meeting
• Project overview, work plan, timeline, important
milestones.
• Steering Committee’s role, purpose, expectations,
organization, and charter.
• Discuss plan review, public outreach capabilities
• Confirm mission statement
• Confirm plan goals
• Review Steering Committee charter
• Confirm natural hazards and hazards of interest
23 10/14 Steering Committee Input Confirm Steering Committee charter via email N/A 10/25 Planning Team call #4 Planning process 7
10/25 Public Outreach Web-based hazard mitigation survey deployed N/A 10/26 Public Outreach Press release announcing the planning process, website and web-based hazard mitigation survey.

N/A
11/15 Planning Team call #5 Planning process 8
12/2 Public Outreach at Concord
Holiday Tree Lighting
Ceremony
Hazard information was shared with the public at the
Community Emergency Response Team booth as well as
distribution of public surveys to complete on-site and postcards publicizing the virtual version of the survey.

About 5,000 at
the event
12/3 Public Outreach at Concord
Senior Craft Fair
Hazard information was shared with the public as well as distribution of public surveys to complete on-site and postcards publicizing the virtual version on the survey.

About 300 at the
event
12/06 Planning Team call #6 Planning process 9
12/13 2nd Steering Committee
Meeting
• Confirm plan objectives
• Risk assessment discussion
• Critical infrastructure mapping request to area agencies • Outreach and engagement update
18 12/20 Planning Team call #7 Planning process 7

City of Concord Hazard Mitigation Plan Plan Development Approach 3-13
Date Event Description Attendance
2023
1/03 Planning Team call #8 Planning process 8
1/17 Planning Team call #9 Planning process 8
1/31 Planning Team call #10 Planning process 9
1/31 Public Outreach Public hazard mitigation survey closed 349 respondents 2/13 Public Outreach Press release announcing the beginning of the draft plan public comment period.

N/A
2/13 Public Outreach Initiate 2-week public comment period for review of the draft plan
N/A
2/14 Planning Team call #11 Planning process 7
2/14 3rd Steering Committee
Meeting
• Draft Plan overview
• Approve mitigation action plan
• Final public survey results
20 2/27 Public Outreach Closure of 2-week public comment period 4 2/28 Planning Team call #12 Planning process XX
TBD Plan Review Plan sent to Cal OES for review and approval pending adoption N/A TBD Approval Pending Adoption Approval pending adoption received from FEMA Region 9 N/A TBD Plan adopted by the Concord
City Council
Plan is finalized with the Council’s adoption N/A
TBD Final Approval FEMA granted final approval of the adopted plan. N/A

4-1

4. CITY OF CONCORD PROFILE
The City of Concord is the largest city in Contra Costa County, located 29 miles northeast of San Francisco.

According to the U.S. Census, the city has a total area of 30.5 square miles. Concord is bordered on the west by Pleasant Hill and the unincorporated community of Pacheco, on the south by Walnut Creek, on the southeast by Clayton, on the northeast by Pittsburg and the unincorporated community of Bay Point, and on the north by the unincorporated community of Clyde. Though it shares no border with Concord, Martinez (the county seat) is located almost immediately adjacent to Concord on the northwest. Concord is connected to San Francisco and Oakland by freeways and the BART system.

4.1 CITY GOVERNMENT
The City of Concord is a general law city with a city council/city manager form of government, and a community- oriented, performance-based management system at the core of decision-making. As its governing body, Concord’s City Council consists of five elected members each representing one of five Council voting districts (see Figure 3-1).

Council members are elected to four-year terms. City voters also elect a city treasurer who serves for a four-year term.

The City Council also serves as the Board of Directors of the Concord/Pleasant Hill Health Care District, the Board of the Local Reuse Authority, and as the Successor Agency to the Redevelopment Agency. Items considered by these bodies are done so on regular City Council agendas.

The Council hires the city manager, who is responsible for all management functions of the City, including preparation of the budget, delivery of services, hiring of personnel, and implementation of capital projects. The City Council also directly hires the city attorney who serves as the City’s primary legal advisor. Municipal elections are consolidated with the general election held every two years in November of even-numbered years. Council terms overlap, with three Councilmembers elected one year and the other two elected two years later. The Council annually selects one of its members to serve as mayor and another as vice mayor. The City Council assumes responsibility for the adoption of this plan; the city manager will oversee its implementation.

4.2 HISTORICAL OVERVIEW
A small tribe of Chupcan (Bay Miwok) Indians composed the first inhabitants of the area that is Concord today. The first city was founded by Salvio Pacheco in 1869 under the name of Todos Santos. It achieved prominence in the 19th century as residents of Pacheco relocated to Todos Santos to avoid fire and flood that crippled Pacheco’s formerly booming economy. The City of Concord was incorporated on February 5, 1905.

North and east of today’s downtown is the older residential area of Concord, with many homes dating back to before the mid-20th century. The southeastern area of the city, centered along Clayton Road, is primarily residential and was mostly developed in the 1960s and 1970s. In the southwest area of the city is the primarily Latino neighborhood known as Four Corners, centered around the intersection of Monument Boulevard and Oak Grove Road.

City of Concord Hazard Mitigation Plan City of Concord Profile 4-2
Todos Santos Plaza, encompassing an entire city block, serves as the focal point of downtown Concord today and has gained fame for its farmers market, free summer concerts, and large number of surrounding restaurants. Much of the area immediately around downtown has recently been redeveloped, with new, high-density apartment and condominium projects to take advantage of nearby public transportation and a park.

In the far northern edge of town is an industrial area, dominated by the Martinez Refinery (which is outside the city limits). The decommissioned Concord Naval Weapons Station to the northeast has been slated for redevelopment into a transit-oriented community. The planning process has encountered delays over the last two decades, but development is anticipated to begin during the implementation period of this hazard mitigation plan.

4.3 PHYSICAL SETTING

4.3.1 Habitats and Surface Waters
The City of Concord is in the Bay Area/Delta Bioregion, as defined by the State’s Natural Communities Conservation Program. This bioregion consists of a variety of natural communities, from salt marshes to chaparral to oak woodlands. The diversity of vegetation found in Contra Costa County is a result of topographic and micro-climate diversity and, combined with the rapid pace of development in the region, has resulted in a high degree of endangerment for local flora and fauna. The primary habitat types include urban, annual grassland, estuarine, coastal brackish marsh, riverine, chaparral, and foothill pine-blue oak woodland. The most prevalent habitat type is urban, which covers the majority of the area within the city limits and is generally continuous to the west and southwest, adjoining the cities of Pleasant Hill and Walnut Creek, respectively. To the east, urban habitat continues into the City of Clayton (City of Concord n.d.-b).

The Concord planning area is bordered to the north—and includes a small part of—the estuarine habitat of Suisun Bay. Bordering the bay is the Avon-Port Chicago Marsh, a relatively extensive area of coastal brackish marsh. This area extends up to 2 miles south toward the developed areas of Concord and is bordered to the west by Pacheco Creek and to the east by Clyde and the tidal portion of the former Concord Naval Weapons Station. Most of this marsh area is considered to be high quality habitat. More patchy brackish marsh habitat is also found beyond these boundaries, both east and west of the planning area along Suisun Bay.

Laced within these diverse habitats are a number of creeks, principally Walnut, Pine, Galindo, and Mount Diablo, and tributaries to the creeks. Although much of the extent of these creeks has been disturbed, the waterways provide important aquatic and riparian habitat, providing resources and movement corridors for flora and fauna. The southern portion of the planning area in the Mount Diablo Foothills contains a number of drainages, including tributaries to Galindo Creek. Intermittent streams and seasonal wetland ponds also occur in the area. Although unmapped, they provide seasonal habitats for local wildlife, including species such as the tiger salamander, which is listed as a special status species by the California Natural Diversity Database. The grassland habitat in the eastern portion of the planning area contains a number of such seasonal wetlands.

4.3.2 Topography
Most of Concord is in nearly level to sloping, with an elevation of 75 feet defined by hills to the southeast and southwest.

City of Concord Hazard Mitigation Plan City of Concord Profile 4-3

4.3.3 Soils and Geology
The 1973 soil survey of Contra Costa County identifies 14 soil associations in the area, as summarized in Table 4-1.

Table 4-1. Identified Soil Types in Contra Costa County Soil % of Total Survey Area Soil % of Total Survey Area Los Osos-Millsholm-Los Gatos 28 Capay-Sycamore-Brentwood 3 Altamont-Diablo-Fontana 26 Capay-Rincon 3
Clear Lake-Cropley 10 Marcuse-Solano-Pescadero 3
Rindge-Kingile 6 Delhi 2
Brentwood-Rincon-Zamora 5 Sacramento-Omni 2
Tierra-Antioch-Perkins 4 Joice-Reyes 2
Rock outcrop-Xerothents 4 Gilroy-Vallecitos 2
Source: Welch, 1973

4.3.4 Climate
Concord has a hot summer Mediterranean climate. Official data from the National Weather Service cooperative station in Concord shows average high temperatures of 57.2 °F in January and 87.8 °F in July. Average low temperatures are 41.6 °F in January and 58.2 °F in July. There are an average of 45 days with highs of 90 °F or higher and 3.8 days with lows of 32 °F or lower. The highest recorded temperature was 112 °F on September 4, 2022 (San Francisco Chronicle 2022). The lowest record temperature was 24 °F on December 23, 1998.

Average annual precipitation is 18.31 inches, falling on an average of 57 days annually. The wettest year was 1995, with 26.62 inches. The driest year was 2007, with 10.57 inches. The most rainfall in one month was 11.79 inches in December 2005, which included the 24-hour maximum rainfall of 3.95 inches on December 31. Table 4-2 summarizes key climate data at the Concord Wastewater Treatment Plant.

Table 4-2. Average Concord Climate Data
Concord Wastewater Plant
Period of record 1991 – 2016
Average Annual Low Temperature 50.3 °F
Average Annual High Temperature 73.3 °F
Average Annual Mean Temperature 64.9 °F
Maximum Temperature 110 °F, July 23, 2006
Minimum Temperature 24 °F, December 23, 1998
Average Annual Precipitation 18.31 inches
One Date Maximum Precipitation 3.95 inches, December 31, 2005 Source: (Western Regional Climate Center 2023)

4.4 SENSITIVE RESOURCES
Historical buildings and locations of significance in Concord include the Galindo Home, which currently serves as the museum for the Concord Historical Society; the Don Fernando Pacheco Adobe, which is the city’s only landmark listed on the national, California, and Concord historical registers; the Port Chicago Naval Magazine National Memorial; and the John Muir National Historic Site.

City of Concord Hazard Mitigation Plan City of Concord Profile 4-4
Concord also is home to several special natural habitat areas. The non-urban areas in the south, east, and north portions of the city are both known and potential habitat for a number of special status animal and plant species.

Lime Ridge supports known populations of Mount Diablo manzanita, Mount Diablo fairy lantern, Diablo helianthella, and Hall’s bush mallow. The ridge provides important habitat for these plant species and is considered a significant ecological area by Contra Costa County.

Mt. Diablo, also considered a county significant ecological area, extends into Concord’s planning area. Portions of the hills within the eastern boundary of the city provide habitat for California tiger salamanders, which have been observed along intermittent streams and seasonal wetland ponds in this area. Much of the grassland area is considered habitat. Intermittent streams and ponds provide habitat for the California red-legged frog, which has been observed on the southeastern portion of the Concord Reuse Project site.

According to the 2030 General Plan, planning for the reuse of the former Concord Naval Weapons Station has required extensive documentation of special status species on the project site. In addition to California red-legged frog, California tiger salamander, and burrowing owl habitat, a number of protected birds have been observed, including golden eagles, bald eagles, loggerhead shrikes, and peregrine falcons. The site also contains potential habitat for the western pond turtle and coast horned lizard, although neither species has been observed. The Concord Reuse Project Area Plan conserves the most sensitive habitat areas on the site as open space (City of Concord n.d.-b).

4.5 DEVELOPMENT PROFILE

4.5.1 Land Use
Much of Concord’s land use pattern can be traced to its evolution as a primary job center within the region, with the focus on Downtown and subsequently on the radiating transportation corridors. Most of the residential development in the City is low-density single-family housing, and much of the commercial development is retail-related. Office, business park, and light industrial uses are located adjacent to transportation infrastructure. Schools and parks are distributed throughout the residential neighborhoods in the city.

Single-family residential is the most significant land use within the city limits. Occupying roughly 6,270 acres, it comprises about 32 percent of the land in Concord. Commercial and mixed use development is clustered in Concord’s downtown and along the major transportation routes that radiate outward from downtown, notably Clayton Road, Monument Boulevard, Willow Pass Road, and areas around the intersection of State Route (SR) 242 and Interstate (I) 680. Industrial uses are primarily situated north of SR 4, and to a lesser extent, south of Monument Boulevard. Table 4-3 summarizes the breakdown of current land use in the City (City of Concord n.d.).

Although Concord has a sizeable inventory of community and neighborhood parks an d recreation opportunities, the vast majority of the acreage in this category comes from open space areas in Los Medanos Hills and the Mount Diablo foothills. Other land uses include vacant and public/quasi -public. These sites are dispersed throughout the City, not clustered in any specific area. Within the existing urbanized area of Concord, 1 percent of the land is vacant and eight percent is used for public/quasi-public use (City of Concord 2012).

The former Concord Naval Weapons Station takes up another significant portion of the city. Historically, the Station was treated as two major subareas—a tidal area along Suisun Bay and an inland area that is predominantly south of Highway 4. Together these areas comprise 7,500 acres and account for 26 percent of the Concord land area.

City of Concord Hazard Mitigation Plan City of Concord Profile 4-5
Table 4-3. General Plan Land Use within the Planning Area Planning Area
Land Use Area (acres) % of total
Single Family Residential 6,270 32.1%
Multi-Family Residential 680 3.5%
Visitor Accommodations 20 0.1%
Commercial Retail 400 2.0%
Auto-Oriented Commercial 90 0.5%
Other Commercial 50 0.3%
Shopping Centers 90 0.5%
Mixed Use 20 0.1%
Office 320 1.6%
Military 145 0.7%
Public/Quasi-Public 1,260 6.4%
Industrial Parks 220 1.1%
General Industrial 340 1.7%
Parks, Recreation, and Open Space 1,421 7.3%
Military – Open Space 2,707 13.8%
Transportation 108 0.6%
Vacant 170 0.9%
Military – Future Development Area 2,233 11.4%
Right-of-way, Washes, and Canals 3,006 15.4%
Total 19,550 100.0%

The designated land use of the tidal area is military. It includes a deep water port used by the Army for weapons shipment, as well as undeveloped land and wetlands. The inland area is now known as the Concord Reuse Project Area. It is transitioning from military to civilian use and is planned for a combination of development and open space.

The Reuse Project Area comprises about 5,000 acres, more than half of which will become parkland under the Concord Reuse Project Area Plan (City of Concord 2012).

4.5.2 Building Stock
According to assessor records, there are 37,576 buildings in the planning area, with a total replacement value of $35.4 billion. The City’s housing stock, predominantly characterized by single-family detached dwelling units, makes up 96 percent of the total building stock. Table 4-4 shows the distribution of buildings by type of use.

Table 4-4. Distribution of Buildings in the Planning Area by Use Type Use Type Number of Buildings Replacement Cost
Residential 35,952 $16,117,411,991
Commercial 911 $11,264,730,796
Industrial 292 $2,990,826,183
Religion 72 $537,998,509
Government 275 $2,677,324,524
Education 54 $1,698,443,146
Total 37,556 $35,286,735,149

City of Concord Hazard Mitigation Plan City of Concord Profile 4-6

4.5.3 Critical Facilities
Critical facilities—those that are essential to the health and welfare of the population (or have a potential to impact public health and welfare)—are especially important after a hazard event. The risk assessment for each hazard in this plan discusses that hazard’s potential impact on critical facilities. For some hazards, potential damage to critical facilities was estimated using the Hazards U.S. (Hazus) computer model developed by FEMA. For this reason, the list of critical facilities was categorized using the following lifeline categories defined in the Hazus model:
• Communications—Infrastructure, Alerts, Warnings, Messages, 911 and Dispatch, Responder Communications and Financial Services
• Energy—Power (Grid), Temporary Power and Fuel
• Food, Water and Sheltering—Evacuations, Schools, Food/Potable Water, Shelter, Durable Goods, Water Infrastructure, and Agriculture
• Hazardous Materials—Facilities, Hazardous Debris, Pollutants and Contaminants • Health and Medical—Medical Care/Hospitals: Patient Movement, Public Health, Fatality Management, Health Care, and Supply Chain
• Safety and Security—Law Enforcement/Security, Search and Rescue, Fire Services, Government Service, Responder Safety, and Imminent Hazard Mitigation
• Transportation—Highway/Roadway, Mass Transit, Railway, Aviation, Maritime and Pipeline Table 4-5 summarizes the number of critical facilities by Hazus-defined category, based on the best data available on critical facilities at the time of this plan. This information is subject to change as new information about critical facilities becomes available during the performance period for this plan. General locations of critical facilities in the planning area are shown on Figure 4-1 and Figure 4-2.

Table 4-5. Planning Area Critical Facilities
Category Types of Facilities Included Number in Planning Area Communications Banks 3
Energy Electric substations, power plants 98
Food, Water & Sheltering Affordable rental housing, water wells 11 Hazardous Materials none identified 0
Health and Medical Health care facilities, hospitals 16 Safety and Security Correctional facilities, fire stations, government buildings, schools, sheriff station
49 Transportation Bridges, rapid transit station 70
Total 247

4.5.4 Development Trends
Development in Concord is guided by the City’s General Plan, which governs land use decision and policy-making.

This hazard mitigation plan will work together with the General Plan to support wise land use in the future by providing vital information on the risk associated with hazards within the city. The City of Concord will incorporate by reference the Hazard Mitigation Plan Update in its General Plan. This will ensure that all future trends in development can be established with the benefits of the information on risk and vulnerability to hazards identified in this plan.

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UV4
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§¨¦680
Treat Blvd
Clayton Rd
Willow Pass Rd
Kirker Pass RdMonument Blvd
Oak Grove Rd
Port Chicago Hwy
Cowell Rd
Galindo St
Concord Blvd
Ygnacio Valley Rd
Mallard
Reservoir
Concord

CRITICAL FACILITIES
Data Sources:

CIty of Concord
0 1 2
Miles
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Figure 4-1.

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Treat Blvd
Clayton Rd
Willow Pass Rd
Kirker Pass RdMonument Blvd
Oak Grove Rd
Port Chicago Hwy
Cowell Rd
Galindo St
Concord Blvd
Ygnacio Valley Rd
Mallard
Reservoir
Concord

CRITICAL FACILITIES
Data Sources:

CIty of Concord
0 1 2
Miles
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Figure 4-2.
(2 of 2)

City of Concord Hazard Mitigation Plan City of Concord Profile 4-9
Recent Development
Table 4-6 summarizes development trends in the performance period since the preparation of the previous hazard mitigation plan, as well as expected future development trends.

Table 4-6. Recent and Expected Future Development Trends Criterion Response
Land annexed since last hazard
mitigation plan
16 parcels for construction of single-family homes, totaling approximately 9 acres.

Land targeted for annexation in next
five years
None
Areas targeted for development or
major redevelopment in the next five
years, and whether any of the areas
interface with known hazard risk areas.

Base Reuse Area
Number of permits for new construction
issued in the City since the preparation
of the previous hazard mitigation plan
2017 2018 2019 2020 2021
Single Family 70 13 24 47 18
Multi-Family 4 1 0 3 0
Other (commercial, mixed use, etc.) 13 2 5 3 5
Total 87 16 29 53 23

Number of new construction permits for
each hazard area (or qualitative
description of where development has
occurred).

Special Flood Hazard Areas: 2
Landslide: 0
Dam Failure Inundation Area: 0
Wildfire Risk Areas: 0
Level of buildout in the City, based on a
buildable lands inventory.

A total of 4,523 residential units can be built on the identified sites within the Housing Element planning period as stated in General Plan.

Projected Future Development
The City is seeing a number of large multifamily residential developments being entitled within the Downtown Specific Plan area, and within the Transit-Oriented Development zone near the Concord BART Station. A mixed-use development on Grant Street currently in development includes 280 residential units. A project near Ellis Lake Park approved on October 6, 2021, includes a six-story apartment building with 183 units and 199 parking spaces (City of Concord 2022).

The current draft of the City’s 6th Cycle Housing Element describes several development projects. The City’s list of approved, but not yet constructed, housing projects includes 1,280 housing units, 430 of which are affordable. These are primarily multifamily units in or near downtown and within a short walking distance of the BART station (City of Concord 2018).

The Naval Weapons Station Base Reuse Area Plan includes approximately 12,000 housing units, 25 percent of which (approximately 3,000 units) are to be affordable to low and very low income residents. The planned development also includes approximately 6 million square feet of commercial space. The City’s portion of the project is still in the planning stages and pending transfer from the Navy. The East Bay Regional Park District now owns a Regional Park/Conservation area of approximately 2,600 acres. Contra Costa County is planning, pending future transfer, a First Responder Training Facility on 75 acres north of State Route 4 (Bjerke 2023).

City of Concord Hazard Mitigation Plan City of Concord Profile 4-10

4.6 DEMOGRAPHIC PROFILE

4.6.1 Population Estimates
Current and Historical Population
The California Department of Finance estimated the population of Concord to be 123,634 as of January 1, 2022.

Table 4-7 shows past population estimates from 2000 to 2020. The risk assessments included in this hazard mitigation plan, performed with FEMA’s Hazus computer program, use a planning area population of 125,410, based on 2020 Census data by Zip code maintained by the City.

Table 4-7. Annual Population Data
Year Population Year Population Year Population
2000 121,872 2007 120.049 2014 126,084
2001 122,874 2008 120,592 2015 127,223
2002 123,415 2009 121,285 2016 129,130
2003 123,061 2010 122,109 2017 129,657
2004 123,119 2011 123,089 2018 129,729
2005 122,373 2012 124,117 2019 129,880
2006 120,732 2013 125,119 2020 129,453
Source: California Department of Finance Historical Population Estimates

Between 2000 and 2020, California’s population grew by 17.5 percent while the planning area’s population increased by 6.2 percent. Figure 4-3 shows the planning area’s annual population growth rates from 2000 to 2020 compared to those of the state. Concord has experienced positive growth in several years over that period.

Source: California Department of Finance Historical Population Estimates

Figure 4-3. California and City of Concord Population Growth Projected Future Population
According to population projections by the California Department of Finance, Contra Costa County’s population should increase to 1,312,536 by 2040 (State of California Department of Finance 2023). This represents a 14.4 percent increase from the 2020 population. This is in line with the County’s 2035 General Plan Land Use Element. -1
0 1
2 3
4 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Annual Growth Rate (%)
City of Concord California

City of Concord Hazard Mitigation Plan City of Concord Profile 4-11

4.6.2 Demographic Indicators for Social Vulnerability
Some populations are at greater risk from hazard events because of decreased resources or physical abilities. People living near or below the poverty line, the elderly, individuals with disabilities, women, children, ethnic minorities, and renters all experience, to some degree, more severe effects from disasters than the general population. These vulnerable populations may vary from the general population in risk perception, living conditions, access to information before, during and after a hazard event, capabilities during an event, and access to resources for post- disaster recovery. Indicators of vulnerability—such as disability, age, poverty, and minority race and ethnicity—often overlap spatially and often in the geographically most vulnerable locations.

Indicators from Census data are commonly used to assess social vulnerability. For the social vulnerability demographic profile component for this plan, the following indicators were selected:
• Population Under 15 Years of Age—Children, especially in the youngest age groups, often cannot protect themselves during a disaster because they lack the necessary resources, knowledge, or life experiences to effectively cope with the situation. Hazard mitigation planning needs to be tailored such that the community is prepared to ensure that children are safe during disaster events and that families with children have access to necessary information and tools.
• Population Over 65 years of Age—People 65 years old and older are likely to require financial support, transportation, medical care, or assistance with ordinary daily activities, especially during disasters. They are more likely to be vision, hearing, and/or mobility impaired, more likely to experience mental impairment or dementia, and more likely to live in assisted-living facilities where emergency preparedness is at the discretion of facility operators. Hazard mitigation needs to account for such needs. • People of Color—Social and economic marginalization of certain racial and ethnic groups, including real estate discrimination, has resulted in greater vulnerability of these groups to all types of hazards. Based on data from a number of studies, African Americans, Native Americans, and populations of Asian, Pacific Islander, or Hispanic origin are likely to be more vulnerable than the broader community. Research shows that minorities are less likely to be involved in pre-disaster planning and experience higher mortality rates during disaster events. Post-disaster recovery often exhibits cultural insensitivity. Since higher proportions of ethnic minorities live below the poverty line than the majority white population, poverty can compound vulnerability. Hazard mitigation plans need to identify the spatial distribution of these population groups and direct resources to reduce their vulnerability to hazards. • Limited English-Speaking Households—For populations with limited English proficiency, disaster communication may be difficult, especially in communities for whom translators and accurate translations of advisories may be scarce. Such households are likely to rely on relatives and local social networks (i.e., friends and neighbors) for information for preparing for a disaster event. • Persons with Disabilities—Persons with disabilities or other access and functional needs are more likely to have difficulty responding to a hazard event than the general population. Family, neighbors, and local government are the first level of response to assist these individuals, and coordination of efforts to meet their access and functional needs is paramount to life safety efforts. Emergency managers need to distinguish between functional and medical needs to plan for incidents that require evacuation and sheltering. Knowing the percentage of population with access and functional needs allows emergency management personnel and first responders to anticipate the services needed by that population. • Families Below the Poverty Level—Economically disadvantaged families have limited ability to absorb losses due to hazard impacts. Wealth enables families to absorb and recover from losses more quickly, due to insurance, savings, and often the availability of low-cost credit. People with lower incomes tend not to have access to these resources. At the same time, poorer families are likely to inhabit poor quality housing and

City of Concord Hazard Mitigation Plan City of Concord Profile 4-12
reside in locations that are most vulnerable to hazard events. Economically disadvantaged neighborhoods are also likely to have relatively poor infrastructure and facilities, which exacerbate the disaster consequences for community members there.
• Renter Occupied Housing Units— People who rent often do so because they do not have the financial resources for home ownership. They often lack access to information about financial aid during recovery. In the most extreme cases, renters lack sufficient shelter options when lodging becomes uninhabitable and limited supply causes housing costs to rise dramatically after a disaster. Renters commonly have limited opportunities for implementing mitigation measures at their home and may not have insurance to cover their personal property. Additionally, renters may not be aware of hazard risks at the property where they live.

Hazard mitigation planning needs to explore ways to ensure that renters are aware of risks and opportunities available to them to mitigate known risks.

These indicators were selected based on the availability of datasets at a small enough resolution to determine probable characteristics of populations within identified hazard areas. The following sections describe these indicators for the planning area.

Age Distribution
The overall age distribution for the planning area is shown in Figure 4-4. Based on the 2019 five-year estimates from the U.S. Census Bureau’s American Community Survey, 14.8 percent of the planning area’s population is 65 or older and 18.7 percent is 14 or younger.

Figure 4-4. Concord Age Distribution
9,509
7,731
6,803
6,831
6,969
20,448
18,441
16,150
9,486
7,785
11,462
5,364
2,248
0 5,000 10,000 15,000 20,000 25,000
Under 5 years
5 to 9 years
10 to 14 years
15 to 19 years
20 to 24 years
25 to 34 years
35 to 44 years
45 to 54 years
55 to 59 years
60 to 64 years
65 to 74 years
75 to 84 years
85 years and over
Number of People
Age

City of Concord Hazard Mitigation Plan City of Concord Profile 4-13
Race, Ethnicity, Language
At the federal level, race and ethnicity in the United States are categorized separately. The most recent U.S. Census officially recognized six racial categories: White American, Black or African American, Native Americans and Alaska Native, Asian American, Native Hawaiian and Other Pacific Islander, and “two or more races.” In completing the census form, each person is asked to choose from among these racial categories, so all Americans are included in the numbers reported for those categories.

Separately, the Census Bureau classifies respondents as “Hispanic or Latino” or “Not Hispanic or Latino,” identifying Hispanic and Latino, the largest minority group in the nation, as an ethnicity not a race. Hispanic and Latino Americans have ethnic origins in a Spanish-speaking country or Brazil. Latin American countries are, like the United States, racially diverse. Consequently, no separate racial category exists for Hispanic and Latino Americans, as they do not constitute a race or a national group. However, the U.S. Supreme Court has unanimously held that, in law, the term “race” is not limited to Census designations but extends to all ethnicities, which may include Jewish, Arab, Italian, Hungarian, Laotian, Zulu, etc.

Any racial category may contain people of Hispanic or Latino ethnicity. For example: the White or European- American race category contains Non-Hispanic Whites and Hispanic Whites; the Black or African American category contains Non-Hispanic Blacks and Hispanic Blacks; the Asian-American category contains Non-Hispanic Asians and Hispanic Asians.

Figure 4-5 shows the racial distribution in the City of Concord according to the 2019 5-year estimates from the U.S.

Census Bureau’s American Community Survey. Figure 4-6 shows the ethnic distribution in the City. The City of Concord has a 24.4 percent foreign-born population. Census data indicate that a majority of the population—89.6 percent—speak a language other than English at home, including 45.6 percent of the total population who speak Spanish at home; another 9.3 percent speak an Asian or Pacific Islander language at home. The census estimates that

51.2 percent of the residents speak English “less than very well.” Source: U.S. Census, 2020

Figure 4-5. Concord Race Distribution
White, 58.2%
Black or African
American, 3.6%
American Indian and
Alaska Native, 0.4%
Asian, 12.8%
Native Hawaiian and
Other Pacific
Islander, 0.6%
Some Other Race,

13.9%
Two or More Races,

10.6%

City of Concord Hazard Mitigation Plan City of Concord Profile 4-14
Source: U.S. Census, 2020

Figure 4-6. Concord Ethnicity Distribution
Individuals with Disabilities or Access and Functional Needs According to the 2020 5-year American Community Survey, 11.7 percent of the residents in Concord live with one or more disabilities. This equates to 14,491 individuals. This includes 6.3 percent with an independent living disability,

5.9 percent with a cognitive difficulty, 5.8 with an ambulatory difficulty, 3.7 percent with a hearing difficulty,

2.0 percent with a self-care difficulty, and 1.8 percent with a vision difficulty. Additional residents with access and functional needs may be unreported.

Income
People living in California must be prepared financially to overcome the inherent risks associated with residing in the state. For the most part, individuals and families are expected to prepare for, respond to and recover from disasters with their personal resources. People with median and low incomes may not recover from a major disaster, and those who are economically disadvantaged likely will not recover. In urban areas such as Concord, the economically disadvantaged often live-in older homes or apartments that may not have been retrofitted or kept current with building codes that would mitigate some of the damage from the disasters prevalent to the area. Renters have no control over the strength and stability of the buildings they live in. All people have a great deal to lose during a disaster, but those economically disadvantaged will lose the most due to their inability to recover.

Based on U.S. Census Bureau estimates, per capita income in the planning area in 2021 was $46,157, and the average household income was $123,084. It is estimated that about 20.7 percent of households receive an income between $100,000 and $149,999 per year, and over 24.7 percent of household incomes are above $150,000 annually. About

11.3 percent of the households in the planning area make less than $25,000 per year and are therefore below the poverty level. The weighted average poverty threshold for a family of four in 2020 was $26,496; for a family of three, $20,591; for a family of two, $16,733.

Mexican, 19.5%
Puerto Rican, 1.2%
Cuban, 0.2%
Other Hispanic or
Latino, 8.2%
White Alone, 47.4%
Asian Alone, 12.5%
Two or more races,

6.5%
Black or African
American Alone, 3.5%
Native American,

0.1%
Native
Hawaiian/Pacific
Islander alone, 0.6%

City of Concord Hazard Mitigation Plan City of Concord Profile 4-15
Homeownership and Renter-Occupied Housing
According to 2020 American Community Survey estimates, there are 46,404 occupied housing units in the City of Concord. Table 4-8 compares general demographic statistics for renter-occupied and owner-occupied housing units.

Table 4-8. Comparative Statistics for Renter-Occupied and Owner-Occupied Housing Units Renter-Occupied Housing Units Owner-Occupied Housing Units Occupied Housing Units
Number 18,508 27,894
% of Total 39.9 percent 60.1 percent
Age of Residents
< 35 28.3 percent 9.4 percent
Time Living at Current Residence
Moved in in 2017 or Later 50.3 percent 20.7 percent
The Social Vulnerability Index
The Centers for Disease Control and Prevention’s Social Vulnerability Index (SVI) uses 16 U.S. census variables to help local officials identify communities that may need support before, during, or after disasters. Social vulnerability refers to the potential negative effects on communities caused by external stresses on human health. Such stresses include natural or human-caused disasters or disease outbreaks. Reducing social vulnerability can decrease both human suffering and economic loss.

This planning effort aligns the social vulnerability threshold with that used in the State of California Hazard Mitigation Plan. High vulnerability is defined by using the overall summary ranking value greater than 0.70. Figure 4-7 shows areas of Concord with high vulnerability rankings. The population living in this area is 27,617 which is 21.5 percent of the total city population.

4.7 ECONOMY

4.7.1 Industry, Businesses and Institutions
With about 66,000 jobs (one out of every seven jobs in Contra Costa County), the City of Concord is the top job center in the county (City of Concord 2022a). With a lower cost of living than Oakland and San Francisco and an easy commute anywhere within the Bay Area, Concord attracts many residents who want to experience the suburban lifestyle with urban amenities. Opportunities to connect with major employers, continue education, and train with industry leaders, coupled with the scenic Mount Diablo backdrop, San Francisco Bay, and comfortable weather makes Concord home for families, entry-level talent, and career transplants (City of Concord n.d.-a). Concord has more than

3.4 million square feet of Class A office space for $2.81 per square foot, a rate that is about half of the cost of office space in nearby San Francisco (City of Concord 2022a). Figure 4-8 shows Census Bureau estimates of the distribution of jobs in Concord by industry.

UV242
UV4
UV4
§¨¦680
Treat Blvd
Clayton Rd
Willow Pass Rd
Kirker Pass RdMonument Blvd
Oak Grove Rd
Port Chicago Hwy
Cowell Rd
Galindo St
Concord Blvd
Ygnacio Valley Rd
Mallard
Reservoir
Concord

HIGH SOCIAL VULNERABILITY AREAS

IN THE PLANNING AREA
Data Sources:

Centers for Disease Control and Prevention
CIty of Concord
0 1 2
Miles
4 High Vulnerability Census Tract
(Summary Ranking Value > 0.70)
Figure 4-7

City of Concord Hazard Mitigation Plan City of Concord Profile 4-17

Figure 4-8. Industry in the Planning Area
The City of Concord identifies the following companies as the top employers in the City (City of Concord n.d.-a):
• Health Care Providers and Medical Organizations—Akesis Health, Cerus Corporation, Fresenius Medical Care, John Muir Health
• Technology—Buildings IOT, Entisys 360
• Manufacturing, Construction, and Engineering—Benchmark, Eichleay, Kyocera, MCE Corporation • Banks—Pacific Service Credit Union, Wells Fargo
• Service Providers—Assetmark, Athens Administrators, Harris & Associates • Other Major Employers—Bay Alarm, BevMo!, Calitho, Conco, Systron Donner Inertial

4.7.2 Employment Trends and Occupations
According to the 5-year American Community Survey (2016-2020), about 67.5 percent of the City of Concord’s population 16 years old or older is in the labor force. Of the working-age population, 86.3 percent of men and

76.1 percent of women are in the labor force. Figure 4-9 shows Census Bureau estimates of employment distribution by occupation category.

Agriculture,
forestry, fishing
and hunting, and
mining

0.5%
Construction

6.6%
Manufacturing

7.6%Wholesale trade

1.8%
Retail trade

10.2%
Transportation and
warehousing, and
utilities

4.4%
Information

2.2%
Finance and
insurance, and real
estate and rental
and leasing

7.7%
Professional,
scientific, and
management, and
administrative and
waste management
services

16.6%
Educational
services, and
health care and
social assistance

20.6%
Arts, entertainment,
and recreation, and
accommodation
and food services

11.0%
Other services

7.1%
Public
administration

3.9%

City of Concord Hazard Mitigation Plan City of Concord Profile 4-18

Figure 4-9. Occupations in the City of Concord
Figure 4-10 compares state and county unemployment trends from 2000 through 2021. Contra Costa County’s unemployment rate was lowest in 2019 at 3.1 percent. The rate peaked at 11.2 percent in 2010 and has declined since then, with the exception of 2020 in the midst of the COVID-19 pandemic. The County unemployment rate has generally been slightly lower than the statewide rate.

Figure 4-10. California and Contra Costa County Unemployment Rate The U.S. Census estimates that over 59.7 percent of workers in the planning area commute alone (by car, truck or van) to work, and mean travel time to work is 30.9 minutes.

Management,
Business, Science
and Arts
41%
Service
21%
Sales & Office
21%
Natural Resources,
Construction and
Maintenance
8%
Production,
Transportation, and
Material Moving
9%
0 2
4 6
8 10
12 14
2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020
UNEMPLOYMENT RATE (%)
California
Contra Costa County

5-1

5. HAZARDS ADDRESSED IN THIS PLAN

5.1 MAJOR PAST HAZARD EVENTS
Federal disaster declarations are typically issued for hazard events that cause more damage than state and local governments can handle without assistance from the federal government. They put local response, reimbursement, and recovery programs into motion to assist public entities’ disaster victims. Some of the programs are matched by state programs. Declarations are made at the county level, and 16 events since 1969 have drawn presidential disaster declarations that applied to Contra Costa County (see Table 5-1). Review of these events helps identify targets for risk reduction and ways to increase a community’s capability to avoid large-scale events in the future.

Table 5-1. Federal Disaster Declarations Applying to Contra Costa County Type of Event FEMA Disaster # Declaration Date
Severe Winter Storms DR-4683-CA January 2023
Covid-19 Pandemic DR-4482 March 2020
Severe Winter Storms, Flooding, And Mudslides DR-4301 February 2017 Severe Storms, Flooding, Mudslides, And Landslides DR-1628 February 2006 Severe Winter Storms and Flooding DR-1203 February 1998 Severe Storms, Flooding, Mud and Landslides DR-1155 January 1997 Severe Storms, Flooding, Mud and Landslides DR-1046 March 1995 Severe Winter Storms, Flooding, Landslides, Mud Flows DR-1044 January 1995 Severe Winter Storm, Mud & Land Slides, & Flooding DR-979 February 1993 Loma Prieta Earthquake DR-845 October 1989
Severe Storms & Flooding DR-758 February 1986
Coastal Storms, Floods, Slides & Tornadoes DR-677 February 1983 Severe Storms, Flood, Mudslides & High Tide DR-651 January 1982 Torrential Rain, High Tide & Winds EM-3078 February 1980 Drought EM-3023 January 1977
Severe Storms & Flooding DR-253 January 1969

Many natural hazard events do not trigger federal disaster declarations but have significant impacts on their communities. These events are also important to consider in establishing recurrence intervals for hazards of concern.

City of Concord Hazard Mitigation Plan Hazards Addressed in This Plan 5-2

5.2 IDENTIFIED HAZARDS OF CONCERN
The Steering Committee considered the full range of natural and human-caused hazards assessed in the 2023 State of California Hazard Mitigation Plan (Table 5-2) that could affect the planning area and then listed hazards that present the greatest concern.

Table 5-2. City of Concord Hazard Comparison with California State Hazards 2023 California
State Hazard Mitigation Plan
2023 City of Concord
Local Hazard Mitigation Plan Comment
Air Pollution Not included This is a concern for the City, but it is dealt with in other planning mechanisms
Civil Disorder Other Hazards of Interest Civil disorder is included in a combined discussion of human- caused hazards
Cyber Threats Other Hazards of Interest Cyber security threats are included in a combined discussion of human-caused hazards
Dam Failure Dam and Levee Failure These hazards are combined in one chapter Drought Drought This local hazard aligns with the State Earthquake Earthquake This local hazard aligns with the State Electromagnetic Pulse Attack Not included This is not a concern for the City Energy Shortage Not included This is a concern for the City, but it is dealt with in other planning mechanisms
Epidemic/Pandemic/Vector-
Borne Disease
Other Hazards of Interest Infectious disease is included in a combined discussion of other hazards of interest
Extreme Cold or Freeze Not included This is not a concern for the City Extreme Heat Severe Weather This hazard was included in a combined discussion of severe weather hazards
Geomagnetic Storm (Space
Weather)
Not included This is a concern for the City, but it is dealt with in other planning mechanisms
Hazardous Materials Release Other Hazards of Interest Hazardous materials incidents are included in a combined discussion of human-caused hazards
Invasive and Nuisance
Species
Not included This is not a concern for the City
Landslide, Debris Flow, and
other Mass Movements
Landslide The City is only concerned about the landslide hazard Levee Failure Dam and Levee Failure These hazards are combined in one chapter Natural Gas Pipeline Hazards Other Hazards of Interest Pipeline interruptions are included in a combined discussion of human-caused hazards
Oil Spills Other Hazards of Interest Discussed with hazardous materials incidents Other Potential Causes of
Long-Term Electrical Outage
Not included This is not a concern for the City
Public Safety Power Shutoff Severe Weather PSPS events are discussed in connection with the severe weather hazard
Radiological Accidents Other Hazards of Interest Radiological materials are mentioned in connection with hazardous materials incidents
Riverine, Stream and Alluvial
Flood
Flood The flood chapter addresses stormwater runoff floods, riverine floods and flash floods

City of Concord Hazard Mitigation Plan Hazards Addressed in This Plan 5-3
2023 California
State Hazard Mitigation Plan
2023 City of Concord
Local Hazard Mitigation Plan Comment
Sea-Level Rise, Coastal
Flooding and Erosion
Not included The City does not border the ocean
Severe Wind, Weather, and
Storms
Severe Weather The severe weather chapter addresses heavy rain, extreme heat and high winds
Snow Avalanche Not included This is not a concern for the City Subsidence Not included This is not a concern for the City Terrorism Other Hazards of Interest Terrorism is included in a combined discussion of human- caused hazards
Transportation Accidents
Resulting in Explosions or
Toxic Releases
Not included This is a concern for the City, but it is dealt with in other planning mechanisms
Tree Mortality Not included This is not a concern for the City Tsunami and Seiche Not included The City does not border the ocean or contain any large bodies of water
Urban Structural Fire Not included This is a concern for the City, but it is dealt with in other planning mechanisms
Volcano Not included This is not a concern for the City Well Stimulation and
Hydraulic Fracturing
Not included This is not occurring in the City
Wildfire Wildfire This is included as a qualitative discussion The process incorporated a review of local hazard planning documents as well as information on the frequency of, magnitude of, and costs associated with hazards that have struck the planning area or could do so. Anecdotal information regarding natural hazards and the perceived vulnerability of the planning area’s assets to them was also used. Based on the review, this plan addresses the following hazards of concern (presented in alphabetical order; the order of listing does not indicate the hazards’ relative severity):
• Climate change
• Dam and levee failure
• Drought
• Earthquake
• Flood
• Mass movement/landslide
• Severe weather
• Wildfire
• Other hazards of interest:
➢ Hazardous materials incidents
➢ Infectious disease
➢ Pipeline incidents
➢ Terrorism, civil disturbance, cybersecurity threats, active shooter incidents ➢ Transportation incidents
➢ Utility interruptions

6-1

6. REGULATIONS AND PROGRAMS
Existing laws, ordinances, plans and programs at the federal and state level can support or impact hazard mitigation actions identified in this plan. Hazard mitigation plans are required to include a review and incorporation, if appropriate, of existing plans, studies, reports, and technical information as part of the planning process (44 CFR, Section 201.6(b)(3)). This chapter presents the relevant information for laws, plans and programs at the federal, state, and local levels.

6.1 FEDERAL AND STATE
This section summarizes federal and state programs that may interface with the actions identified in this plan. Each program enhances capabilities to implement mitigation actions or has a nexus with a mitigation action in this plan.

State and federal regulations and programs that need to be considered in hazard mitigation are constantly evolving.

For this plan, a review was performed to determine which regulations and programs are currently most relevant to hazard mitigation planning. The findings are summarized in Table 6-1 and Table 6-2. Short descriptions of each program are provided in Appendix B.

Table 6-1. Summary of Relevant Federal Agencies, Programs and Regulations Agency, Program or Regulation
Hazard Mitigation
Area Affected Relevance
Americans with Disabilities Act Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Civil Rights Act of 1964 Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Clean Water Act Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Community Development Block
Grant Disaster Resilience
Program
Action Plan
Funding
This is a potential alternative source of funding for actions identified in this plan.

Community Rating System Flood Hazard This voluntary program encourages floodplain management activities that exceed the minimum National Flood Insurance Program requirements.

Disaster Mitigation Act Hazard Mitigation
Planning
This is the current federal legislation addressing hazard mitigation planning.

Emergency Relief for Federally
Owned Roads Program
Action Plan
Funding
This is a possible funding source for actions identified in this plan.

Emergency Watershed Program Action Plan
Funding
This is a possible funding source for actions identified in this plan.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-2
Agency, Program or Regulation
Hazard Mitigation
Area Affected Relevance
Endangered Species Act Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

Federal Energy Regulatory
Commission Dam Safety
Program
Dam Failure
Hazard
This program cooperates with a large number of federal and state agencies to ensure and promote dam safety.

National Dam Safety Act Dam Failure
Hazard
This act requires a periodic engineering analysis of most dams in the country
National Environmental Policy
Act
Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable federal acts.

National Flood Insurance
Program
Flood Hazard This program makes federally backed flood insurance available to homeowners, renters, and business owners in exchange for communities enacting floodplain regulations
National Incident Management
System
Action Plan
Development
Adoption of this system for government, nongovernmental organizations, and the private sector to work together to manage incidents involving hazards is a prerequisite for federal preparedness grants and awards
Presidential Executive Order
11988 (Floodplain Management)
Flood Hazard This order requires federal agencies to avoid long and short-term adverse impacts associated with modification of floodplains Presidential Executive Order
11990 (Protection of Wetlands)
Action Plan
Implementation
FEMA hazard mitigation project grant applications require full compliance with applicable presidential executive orders.

U.S. Army Corps of Engineers
Dam Safety Program
Dam Failure
Hazard
This program is responsible for safety inspections of dams that meet size and storage limitations specified in the National Dam Safety Act.

U.S. Army Corps of Engineers
Flood Hazard Management
Flood Hazard,
Action Plan
Implementation,
Action Plan
Funding
The Corps of Engineers offers multiple funding and technical assistance programs available for flood hazard mitigation actions

Table 6-2. Summary of Relevant State Agencies, Programs and Regulations Agency, Program or Regulation
Hazard Mitigation
Area Affected Relevance
AB 32: The California Global
Warming Solutions Act
Action Plan
Development
This act establishes a state goal of reducing greenhouse gas emissions to 1990 levels by 2020
AB 70: Flood Liability Flood Hazard A city or county may be required to partially compensate for property damage caused by a flood if it unreasonably approves new development in areas protected by a state flood control project
AB 162: Flood Planning Flood Hazard Cities and counties must address flood-related matters in the land use, conservation, and safety and housing elements of their general plans.

AB 747: General Plans—Safety
Element
Hazard Mitigation
Planning
The safety elements of cities’ and counties’ general plans must address evacuation routes and include any new information on flood and fire hazards and climate adaptation and resiliency strategies.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-3
Agency, Program or Regulation
Hazard Mitigation
Area Affected Relevance
AB 2140: General Plans—Safety
Element
Hazard Mitigation
Planning
This bill enables state and federal disaster assistance and mitigation funding to communities with compliant hazard mitigation plans.

AB 2800: Climate Change—
Infrastructure Planning
Action Plan
Development
This act requires state agencies to take into account the impacts of climate change when developing state infrastructure.

Alquist-Priolo Earthquake Fault
Zoning Act
Earthquake Hazard This act restricts construction of buildings used for human occupancy on the surface trace of active faults.

California Department of Water
Resources
Flood Hazard This state department is the state coordinating agency for floodplain management.

California Division of Safety of
Dams
Dam Failure
Hazard
This division monitors the dam safety program at the state level and maintains a working list of dams in the state.

California Environmental Quality
Act
Action Plan
Implementation
This act establishes a protocol of analysis and public disclosure of the potential environmental impacts of development projects.

Any project action identified in this plan will seek full California Environmental Quality Act compliance upon implementation.

California General Planning Law Hazard Mitigation
Planning
This law requires every county and city to adopt a comprehensive long-range plan for community development, and related laws call for integration of hazard mitigation plans with general plans.

California Multi-Hazard Mitigation
Plan
Hazard Mitigation
Planning
Local hazard mitigation plans must be consistent with their state’s hazard mitigation plan.

California Residential Mitigation
Program
Earthquake Hazard This program helps homeowners with seismic retrofits to lessen the potential for damage to their houses during an earthquake.

California State Building Code Action Plan
Implementation
Local communities must adopt and enforce building codes, which include measures to improve buildings’ ability to withstand hazard events.

Disadvantaged and Low-Income
Communities Investments
Action Plan
Funding
This is a potential source of funding for actions located in disadvantaged or low-income communities.

Division of the State Architect’s
AB 300 List of Seismically At-Risk
Schools
Earthquake
Hazard, Action Plan
Development
The Division of the State Architect recommends that local school districts conduct detailed seismic evaluations of seismically at- risk schools identified in the inventory that was required by AB 300.

Governor’s Executive Order S-13-
08 (Climate Impacts)
Action Plan
Implementation
This order includes guidance on planning for sea-level rise in designated coastal and floodplain areas for new projects.

Senate Bill 92: Public Resources
Portion of Biennial Budget Bill
Dam Failure
Hazard
This bill requires dams (except for low-risk dams) to have emergency action plans that are updated every 10 years and inundation maps updated every 10 years, or sooner if specific circumstances change.

Senate Bill 97: Guidelines for
Greenhouse Gas Emissions
Action Plan
Implementation
This bill establishes that greenhouse gas emissions and the effects of greenhouse gas emissions are appropriate subjects for California Environmental Quality Act analysis.

Senate Bill 99: General Plans:

Safety Element: Emergency
Evacuation Routes
Action Plan
Implementation
This bill requires the safety element must include information to identify residential developments in hazard areas that do not have at least two emergency evacuation routes.

Senate Bill 379: General Plans:

Safety Element—Climate
Adaptation
Action Plan
Implementation
This bill requires cities and counties to include climate adaptation and resiliency strategies in the safety element of their general plans.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-4
Agency, Program or Regulation
Hazard Mitigation
Area Affected Relevance
Senate Bill 1000: General Plan
Amendments—Safety and
Environmental Justice Elements
Action Plan
Implementation
Under this bill, review and revision of general plan safety elements are required to address only flooding and fires (not climate adaptation and resilience), and environmental justice is required to be included in general plans.

Senate Bill 1035: Fire, Flood, and
Adaptation Safety Element
Updates
Action Plan
Implementation
Clarifies that revisions to the Safety Element to address fire hazards, flood hazards, and climate adaptation and resilience strategies all must occur upon each revision to a Housing Element or Local Hazard Mitigation Program.

Standardized Emergency
Management System
Action Plan
Implementation
Local governments must use this system to be eligible for state funding of response-related personnel costs.

6.2 CITY OF CONCORD
This section identifies local programs, plans, and studies that can support or enhance the core capabilities of the City.

Each can be leveraged by the City to support or enhance the implementation of mitigation actions identified in this plan. These programs, plans and studies are hereby integrated into this hazard mitigation plan by reference— mitigation actions identified in any of them are considered to be fully integrated into this hazard mitigation plan by reference.

6.2.1 General Plan
The Concord General Plan is a comprehensive set of purposes, policies and programs to guide the future form and development of the city. The plan is approved by the City Council and the mayor and adopted by the Planning Commission. The General Plan is a strategic long-term document that is implemented by decisions that direct the allocation of public resources and that shape private development, which affects the lives of residents and the business community. The General Plan is prepared and maintained by the Department of City Planning and must comply with the California General Planning Law. The law requires specific planning elements, including land use, circulation, housing, conservation, open space, noise, safety, and air quality. The City of Concord’s General Plan consists of the following elements:
• Economic vitality
• Land use
• Growth management
• Transportation
• Parks, open space and conservation
• Safety and noise
• Public facilities and utilities
• Housing
The Safety Element includes a discussion of geologic and seismic hazards, wildfire hazards, hazardous materials, and health and safety services. The hazard mitigation plan was adopted as an implementation appendix to the Safety Element.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-5

6.2.2 City of Concord Emergency Operations Plan
The Emergency Operations Plan addresses the City’s responsibilities in emergencies associated with natural disaster, human-caused emergencies and technological incidents. It provides a framework for coordination of response and recovery efforts within the city in coordination and with local, state, and federal agencies. The plan establishes an emergency organization to direct and control operations during a period of emergency by assigning responsibilities to specific personnel. Information from the hazard mitigation plan is incorporated as appropriate.

6.2.3 Local Emergency Volunteer Management Plan
This plan establishes a framework by which the City of Concord can coordinate unaffiliated spontaneous and affiliated volunteer resources for community-wide response, relief, and recovery following a disaster.

6.2.4 Citywide Climate Action Plan
The City’s Climate Action Plan includes projects for reducing greenhouse gas emissions and adapting to likely impacts of climate change. These projects were reviewed to identify cross-planning initiatives that serve both adaptation and mitigation objectives.

6.2.5 Care and Shelter for People with Disabilities and Functional Needs The City addresses the needs of individuals with disabilities and the elderly during an emergency or disaster situation, and provides safe, sanitary, secure shelter and care for all residents including those with functional needs.

6.2.6 California Environmental Quality Act (CEQA)
The City enforces the requirements of CEQA, which, since 1988, requires mitigation for identified natural hazards.

6.2.7 Post-Disaster Recovery Plan
The departments of the City of Concord provide vital services to residents, so reliability is a fundamental mission for every City department. Currently, such planning was each department’s responsibility. The content and structure of continuity of operations plans (COOP), operational standards, and coordination with other departments, if any, were left to the discretion of individual departments. A Post-Disaster Recovery Plan will serve as a supplemental tool designed to help City departments effectively resume day-to-day core services and functions following a disaster.

6.3 CAPABILITY ASSESSMENT
The planning team performed an inventory and analysis of existing authorities and capabilities called a “capability assessment.” A capability assessment creates an inventory of a jurisdiction’s codes, programs and policies, and evaluates its capacity to carry them out. It presents a toolkit for implementing the hazard mitigation plan and for identifying opportunities to increase the City’s core capabilities to support mitigation actions. The assessment identifies potential gaps in core capabilities. Filling those gaps may eventually become mitigation actions in the plan.

Assessment findings were shared with City departments as they developed the recommended mitigation actions. If a department identified an opportunity to add or expand a capability, then doing so has been identified as a mitigation action. The City views each core capability to be fully adaptable as needed to meet the best interests of the City. This adaptability is an overarching City capability that is acknowledged by this reference.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-6

6.3.1 Planning and Regulatory Capabilities
Jurisdictions have the ability to develop policies and programs and to implement rules and regulations to protect and serve residents. Local policies are typically identified in a variety of community plans, implemented via a local ordinance, and enforced through a governmental body. An assessment of planning and regulatory capabilities is presented in Table 6-3.

Table 6-3. Planning and Regulatory Capability
Local Authority Other Jurisdiction
Authority State Mandated Integration
Opportunity?
Codes, Ordinances, & Requirements
Building Code Yes Yes Yes Yes
Comment: California Code of Regulations Title 24, and Municipal Code Chapter 15. Last amended December 6November 1, 202216, effective January 51, 202317. Fire Code regulated by Contra Costa County Fire Protection District. Title 24 regulated by the State of CA.

Zoning Code Yes Yes No Yes
Comment: 2030 General Plan, Zoning Plan Chapter 3 Land Use. Adopted October 2, 2007, Amended January 6, 2015 Subdivisions Yes Yes Yes Yes
Comment: Municipal Code, Title 17 Subdivisions. (Ord. No. 17-9 (Exh. A)) Amended September 5, 2017.

Stormwater Management Yes Yes Yes Yes
Comment: Municipal Code Chapter 16.05 Ord. No. 04-4 Date of last update 2004.

Post-Disaster Recovery No No No No
Comment:

Real Estate Disclosure Yes Yes Yes No
Comment: Cal.Civ. Code §1102 et seq. Amended in 1999, effective January 1, 2000.

Growth Management Yes No Yes No
Comment: Cal.Gov. Code §65300 et seq. Amended in 1984.

Site Plan Review Yes Yes No Yes
Comment: Municipal Code, Chapter 18.10 Title, Purpose, Applicability and Interpretation. Section 65850 et seq. of the California Government Code. [Ord. 12-4. DC 2012 § 122-1] Amended August 23, 2012.

Environmental Protection Yes Yes Yes Yes
Comment: California Environmental Quality Act (Guideline: California Code of Regulations, Title 14, Division 6, Chapter3.

Sections 15000-15387) Amended January 1, 2016.

Flood Damage Prevention Yes Yes Yes Yes
Comment: Municipal Code Chapter 15.75, Floodplain Management.(Ord. No. 10-1) Date of last update April 13, 2010.

Emergency Management Yes Yes Yes Yes
Comment: Code 1965, § 3600; Code 2002, § 22-1. Ord. No. 858. Date of last amendment 2016 Climate Change Yes Yes Yes Yes
Comment: California SB-379: Land Use: General Plan: Safety Element, Amended October 8, 2015. Citywide Climate Action Plan, adopted July 23, 2013.

Other: N/A N/A N/A N/A
Comment:

City of Concord Hazard Mitigation Plan Regulations and Programs 6-7
Local Authority Other Jurisdiction
Authority State Mandated Integration
Opportunity?
Planning Documents
General Plan Yes Yes Yes Yes
Is the plan compliant with Assembly Bill 2140? Yes
Comment: City of Concord 2030 General Plan, Chapter 7: Safety and Noise. Elements include: Fault Rapture Hazards, Ground Shaking Susceptibility, Liquefaction Potential, Wildfire Hazards, Hazardous Materials and Health and Safety Services.

Capital Improvement Plan Yes No No Yes
How often is the plan updated? 2 years
Comment: Last updated 2022
Floodplain or Watershed Plan Yes Yes Yes Yes
Comment: Last updated 2010
Stormwater Plan Yes Yes Yes Yes
Comment: Last updated 2004
Urban Water Management Plan No Yes Yes No
Comment: Contra Costa Water District
Habitat Conservation Plan Yes Yes Yes Yes
Comment: Municipal Code Chapter 18.305, Creek and Riparian Habitat Protection- Ord. 12-4. DC 2012 § 122-799 -last updated 2012
Economic Development Plan Yes No No No
Comment: On April 11, 2017 an Economic Vitality Strategy Initiative was presented to council, updated in January 2020.

Shoreline Management Plan No N/A N/A N/A
Comment:

Community Wildfire Protection Plan No N/A N/A N/A
Comment:

Forest Management Plan No N/A N/A N/A
Comment:

Climate Action Plan Yes Yes Yes Yes
Comment: Last updated July 23, 2013.

Emergency Operations Plan Yes Yes Yes Yes
Comment: A Resolution to Adopt the City of Concord’s Emergency Operations Plan Dated March 22, 2016 Threat & Hazard Identification & Risk
Assessment (THIRA)
No Yes Yes No
Comment: County Office of Emergency Services
Post-Disaster Recovery Plan No Yes Yes Yes
Comment: Office of Emergency Services
Continuity of Operations Plan Yes Yes No Yes
Comment: Office of Emergency Services
Public Health Plan No Yes Yes Yes
Comment: Contra Costa County Health Services

City of Concord Hazard Mitigation Plan Regulations and Programs 6-8

6.3.2 Integration Opportunity
The assessment looked for opportunities to integrate this mitigation plan with the planning and regulatory capabilities identified. Capabilities were identified as integration opportunities if they can support or enhance the actions identified in this plan or be supported or enhanced by components of this plan. The City considered actions to implement this integration. The column in Table 6-3 labeled “Integration Opportunity” identifies capabilities that can support or be supported by components of this plan. Where “yes” is indicated in this column, the City has considered actions to integrate these capabilities with the plan. The following is an example of future integration:
• Post-Disaster Recovery Plan—The departments of the City of Concord provide vital services to its residents. As a result, reliability is the fundamental mission of every department in the City. The content and structure of continuity of operations plans, operational standards, and coordination with other departments, is left to the discretion of individual departments. A continuity of operations plan will serve as a supplemental tool to help City departments effectively resume day-to-day core services and functions following a disaster.

6.3.3 Administrative and Technical Capabilities
Planning, regulatory, and fiscal capabilities provide the backbone for successfully developing a mitigation strategy; however, without appropriate personnel, the strategy may not be implemented. Administrative and technical capabilities focus on the availability of personnel resources responsible for implementing all the facets of hazard mitigation. These resources include technical experts, such as engineers and scientists, as well as personnel with capabilities that may be found in multiple departments, such as grant writers. An assessment of administrative and technical capabilities is presented in Table 6-4.

Table 6-4. Administrative and Technical Capability
Staff/Personnel Resource Available? Department/Agency/Position Planners or engineers with knowledge of land development and land management practices
Yes Planning, Community Development
Engineers or professionals trained in building or
infrastructure construction practices
Yes Community Development
Planners or engineers with an understanding of natural
hazards
Yes Community Development
Staff with training in benefit/cost analysis Yes Finance Surveyors No
Personnel skilled or trained in GIS applications Yes Information Technology Scientist familiar with natural hazards in local area No Emergency Manager Yes Police Department
Grant writers Yes Various
Other N/A

6.3.4 Fiscal Capabilities
Assessing a jurisdiction’s fiscal capability provides an understanding of the ability to fulfill the financial needs associated with hazard mitigation projects. This assessment identifies both outside resources, such as grant-funding eligibility, and local jurisdictional authority to generate internal financial capability, such as through impact fees. An assessment of fiscal capabilities is presented in Table 6-5.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-9
Table 6-5. Fiscal Capability
Financial Resource Accessible or Eligible to Use?
Community Development Block Grants Yes
Capital Improvements Project Funding Yes
Authority to Levy Taxes for Specific Purposes Yes
User Fees for Water, Sewer, Gas or Electric Service Yes, sewer fees Incur Debt through General Obligation Bonds Yes
Incur Debt through Special Tax Bonds Yes
Incur Debt through Private Activity Bonds No
Withhold Public Expenditures in Hazard-Prone Areas Yes
State-Sponsored Grant Programs Yes
Development Impact Fees for Homebuyers or Developers Yes

6.3.5 Participation in Other Programs
Other programs, such as the Community Rating System and Firewise USA, can enhance a jurisdiction’s ability to mitigate, prepare for, and respond to natural hazards. These programs indicate a jurisdiction’s desire to go beyond minimum regulatory requirements in order to create a more resilient community. These programs focus on communication, mitigation, and community preparedness to minimize the impact of natural hazards on a community.

Classifications under various community mitigation programs are presented in Table 6-6.

Table 6-6. Community Classifications
Participating? ID Number Classification Date Classified FIPS Code Yes 06-16000 N/A N/A
Unique Entity Identifier Yes R18EUE4LETK7 N/A N/A
Community Rating System Yes N/A 6 5/1/2020
Building Code Effectiveness Grading Schedule Yes N/A 2 4/11/12 Public Protection No N/A N/A N/A
Storm Ready No N/A N/A N/A
Firewise No N/A N/A N/A

6.3.6 Development and Permitting Capability
Jurisdictions regulate land use through the adoption and enforcement of zoning, subdivision and land development ordinances, building codes, building permit ordinances, floodplain, and stormwater management ordinances. When effectively prepared and administered, these regulations can lead to hazard mitigation. Development and permitting capabilities are presented in Table 6-7.

6.3.7 NFIP Compliance
Flooding is the costliest natural hazard in the United States. Community participation in the NFIP opens up opportunity for additional grant funding associated specifically with flooding issues. Assessment of the jurisdiction’s current NFIP status and compliance provides planners with a greater understanding of the local flood management program, opportunities for improvement, and available grant funding opportunities. Information on NFIP compliance is presented in Table 6-8.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-10
Table 6-7. Development and Permitting Capability
Criterion Response
Does your jurisdiction issue development permits? Yes
If no, who does? If yes, which department? Community Development Department Does your jurisdiction have the ability to track permits by hazard area?
Yes
For flood map and seismic fault zone only
Does your jurisdiction have a buildable lands inventory? Yes If yes, please briefly describe. Inventory of the housing potential on vacant sites is within the Concord 2014-2022 Housing Element, Category 2-8 and the Draft Housing Element (2023-2031) in Appendix E.

If no, please quantitatively describe the level of buildout in the jurisdiction.

N/A

Table 6-8. National Flood Insurance Program Compliance
Criterion Response
What local department is responsible for floodplain management? Community Development Who is your floodplain administrator? (department/position) Community Development/Current Development Manager
Are any certified floodplain managers on staff in your jurisdiction? Yes, 3 What is the date that your flood damage prevention ordinance was last amended?
4/13/2010
Does your floodplain management program meet or exceed minimum requirements?
Exceeds
If exceeds, in what ways? CRS Class 6 City of Concord has one foot of freeboard requirement.

When was the most recent Community Assistance Visit or Community Assistance Contact?
3/1/2007
Does your jurisdiction have any outstanding NFIP compliance violations that need to be addressed?
No
If so, please state what they are. N/A
Do your flood hazard maps adequately address the flood risk within your jurisdiction?
Yes
If no, please state why. N/A
Does your floodplain management staff need any assistance or training to support its floodplain management program?
No
If so, what type of assistance/training is needed? N/A
Does your jurisdiction participate in the Community Rating System (CRS)? Yes If yes, is your jurisdiction interested in improving CRS Classification? No Is your jurisdiction interested in joining the CRS program? N/A How many Flood Insurance policies are in force in your jurisdiction?a 242 What is the insurance in force? $72,619,900
What is the premium in force? $216,932
How many total loss claims have been filed in your jurisdiction? a 66 What were the total payments for losses? $113,713
a. According to FEMA statistics as of September 30, 2022

City of Concord Hazard Mitigation Plan Regulations and Programs 6-11

6.3.8 Public Outreach Capability
Regular engagement with the public on issues regarding hazard mitigation provides an opportunity to directly interface with community members. Assessing this outreach and education capability illustrates the connection between the government and community members, which opens a two-way dialogue that can result in a more resilient community based on education and public engagement. An assessment of education and outreach capabilities is presented in Table 6-9.

Table 6-9. Education and Outreach
Criterion Response
Do you have a Public Information Officer or Communications Office? Yes Do you have personnel skilled or trained in website development? Yes, Information Technology Do you have hazard mitigation information available on your website? Yes If yes, please briefly describe. Emergency Preparedness, Hazard Mitigation Plan
Do you utilize social media for hazard mitigation education and outreach?
Yes
If yes, please briefly describe. City and Police Department Do you have any citizen boards or commissions that address issues related to hazard mitigation?
Yes
If yes, please briefly describe. Planning Commission
Do you have any other programs already in place that could be used to communicate hazard-related information?
Yes
If yes, please briefly describe. e-newsletter to subscriber interest list, Nextdoor.com, Police Dept., Concord CERT
Do you have any established warning systems for hazard events? Yes If yes, please briefly describe. Contra Costa County Community Warning System

6.3.9 Adaptive Capacity
An adaptive capacity assessment evaluates a jurisdiction’s ability to anticipate impacts from future conditions. By looking at public support, technical adaptive capacity, and other factors, jurisdictions identify their core capability for resilience against issues such as sea level rise. The adaptive capacity assessment provides jurisdictions with an opportunity to identify areas for improvement by ranking their capacity high, medium, or low. The community’s adaptive capacity for the impacts of climate change is presented in Table 6-10.

City of Concord Hazard Mitigation Plan Regulations and Programs 6-12
Table 6-10. Adaptive Capacity for Climate Change
Criterion Jurisdiction Ratinga
Technical Capacity
Jurisdiction-level understanding of potential climate change impacts Medium Comments: City’s Climate Action Plan and CRP Climate Action Plan.

Jurisdiction-level monitoring of climate change impacts Medium Comments: Planning Division participates in County sustainability exchange.

Technical resources to assess proposed strategies for feasibility and externalities Low Comments: None provided
Jurisdiction-level capacity for development of greenhouse gas emissions inventory Medium Comments: Through consultants for larger projects
Capital planning and land use decisions informed by potential climate impacts Low Comments: None provided
Participation in regional groups addressing climate risks High Comments: Planning Division participates in County sustainability exchange.

Implementation Capacity
Clear authority/mandate to consider climate change impacts during public decision-making processes
Medium
Comments: City Council advocacy for advancing Climate Action.

Identified strategies for greenhouse gas mitigation efforts Medium Comments: City’s Climate Action Plan and CRP Climate Action Plan.

Identified strategies for adaptation to impacts Low
Comments: None provided
Champions for climate action in local government departments Medium Comments: City council advocacy for advancing Climate Action.

Political support for implementing climate change adaptation strategies Low Comments: None provided
Financial resources devoted to climate change adaptation Low Comments: None provided
Local authority over sectors likely to be negative impacted Low Comments: None provided
Public Capacity
Local residents knowledge of and understanding of climate risk Medium Comments: Responses to the hazard mitigation public survey conducted in Concord in 2022/23 indicate a significant number of respondents understand the impacts of climate change.

Local residents support of adaptation efforts Medium
Comments: Responses to the hazard mitigation public survey conducted in Concord in 2022/23 indicate a large number of respondents are concerned about climate change impacts.

Local residents’ capacity to adapt to climate impacts Medium Comments: Responses to the hazard mitigation public survey conducted in Concord in 2022/23 suggest an understanding among respondents of the need to adapt to climate impacts.

Local economy current capacity to adapt to climate impacts Low Comments: None provided
Local ecosystems capacity to adapt to climate impacts Low Comments: None provided
a. High = Capacity exists and is in use; Medium = Capacity may exist but is not used or could use some improvement; Low = Capacity does not exist or could use substantial improvement; Unsure= Not enough information is known to assign a rating.

City of Concord Hazard Mitigation Plan
PART 2—RISK ASSESSMENT

7-1

7. RISK ASSESSMENT METHODOLOGY
The risk assessments in this plan describe the risks associated with each identified hazard of concern. The following steps were used to define the risk of each hazard:
• Identify and profile each hazard—The following information is given for each hazard:
➢ A summary of past events that have impacted the planning area ➢ Geographic areas most affected by the hazard
➢ Event frequency estimates
➢ Severity descriptions
➢ Warning time likely to be available for response
• Determine exposure to each hazard—Exposure was assessed by overlaying hazard maps with an inventory of structures, facilities, and systems to decide which of them would be exposed to each hazard. • Assess the vulnerability of exposed facilities—Vulnerability of exposed structures and infrastructure was evaluated by interpreting the probability of occurrence of each event and assessing structures, facilities, and systems that are exposed to each hazard. Tools such as GIS and Hazus were used for this assessment for the dam failure, earthquake, flood, and tsunami hazards. Outputs similar to those from Hazus were generated for other hazards, using data generated through GIS.

7.1 RISK ASSESSMENT TOOLS

7.1.1 Mapping
National, state, county, and city databases were reviewed to locate available spatially based data relevant to this planning effort. Maps were produced using geographic information system (GIS) software to show the spatial extent and location of hazards when such datasets were available. The maps are included in the hazard profile chapters. Data used for this plan represents the best science currently available. Sources and methods used to generate the maps are described in Appendix C.

7.1.2 Modeling
Overview
FEMA developed the standardized GIS-based software program Hazards U.S. (Hazus) to estimate losses caused by earthquakes, hurricanes and floods and identify areas that face the highest risk and potential for loss. Hazus is used to support risk assessments, mitigation planning, and emergency planning and response. It provides a wide range of inventory data, such as demographics, building stock, critical facilities, and transportation and utility infrastructure, and multiple models to estimate potential losses from natural disasters. The program maps and calculates hazard data and damage and economic loss estimates for buildings and infrastructure. Its advantages include the following:

City of Concord Hazard Mitigation Plan Risk Assessment Methodology 7-2
• Provides a consistent methodology for assessing risk across geographic and political entities. • Provides a way to save data so that they can readily be updated as population, inventory, and other factors change and as mitigation planning efforts evolve.
• Facilitates review of mitigation plans because it helps to ensure that FEMA methodologies are incorporated. • Supports grant applications by calculating benefits using FEMA definitions and terminology. • Produces hazard data and loss estimates that can be used in communication with local stakeholders. • Is administered by the local government and can be used to manage and update a hazard mitigation plan throughout its implementation.

For flood-related hazards, Hazus calculates losses to structures due to inundation by looking at depth of flooding and type of structure. Using historical flood insurance claim data, Hazus estimates the percentage of damage to structures and their contents by applying established damage functions to an inventory. The Hazus analysis also estimates the quantity of debris that would be caused by a dam failure.

For earthquake, once the location and size of a hypothetical earthquake are identified, Hazus estimates the intensity of the ground shaking, the number of buildings damaged, the number of casualties, the damage to transportation systems and utilities, the number of people displaced from their homes, and the estimated cost of repair and clean up.

Levels of Detail for Evaluation
Hazus provides default data for inventory, vulnerability, and hazards; these default data can be supplemented with local data to provide a more refined analysis. The model can carry out three levels of analysis:
• Level 1—All of the information needed to produce an estimate of losses is included in the software’s default data. These data are derived from national databases and describe in general terms the characteristic parameters of the planning area.
• Level 2—More accurate estimates of losses require more detailed information about the planning area. To produce Level 2 estimates of losses, detailed information is required about local geology, hydrology, hydraulics, and building inventory, as well as data about utilities and critical facilities. This information is needed in a GIS format.
• Level 3—This level of analysis generates the most accurate estimate of losses. It requires detailed engineering and geotechnical information to customize it for the planning area.

7.2 RISK ASSESSMENT APPROACH

7.2.1 Hazard Profile Development
Hazard profiles were developed through web-based research and review of previously developed local and state reports and plans. Frequency and severity indicators include past events and the expert opinions of geologists, emergency management specialists, and others.

7.2.2 Assessment of Exposure and Vulnerability
The risk assessment for this plan determined exposure and vulnerability to the planning area hazards of concern for the overall planning area and for each council voting district. The approach used for each hazard is described below.

City of Concord Hazard Mitigation Plan Risk Assessment Methodology 7-3
Flood, Dam Failure, and Earthquake
Community exposure and vulnerability to the following hazards were evaluated using Hazus:
• Flood—A Level 2 user-defined analysis was performed for general building stock in flood zones and for critical facilities. Current flood mapping for the planning area was used to delineate flood hazard areas and estimate potential losses from the 1-percent-annual-chance and 0.2-percent-annual-chance flood events. To estimate damage that would result from a flood, Hazus uses pre-defined relationships between flood depth at a structure and resulting damage, with damage given as a percent of total replacement value. Curves defining these relationships have been developed for damage to structures and for damage to typical contents within a structure. By inputting flood depth data and known property replacement cost values, dollar-value estimates of damage were generated.
• Earthquake—A Level 2 analysis was performed to assess earthquake exposure and vulnerability for four scenario events:
➢ The Hazus-defined 100-year probabilistic event
➢ A Magnitude 6.8 event on the Concord-Green Valley Fault with an epicenter 23.5 miles north-northwest of Concord.
➢ A Magnitude 7.05 event on the Hayward Fault with an epicenter 14 miles south-southwest of Concord. ➢ A Magnitude 6.7 event on the Mount Diablo Fault with an epicenter 11.5 miles southeast of Concord.

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

All Other Assessed Hazards
Historical datasets were not adequate to model future losses for most of the hazards of concern. However, areas and inventory susceptible to some of the hazards of concern were mapped by other means, and exposure was evaluated. A qualitative analysis was conducted for other hazards using the best available data and professional judgment.

Socially Vulnerable Populations
Hazard impacts on socially vulnerable populations were assessed using the Centers for Disease Control and Prevention’s Social Vulnerability Index (SVI), which assesses social vulnerability based on 16 U.S. Census variables.

The vulnerability of Census tracts was categorized as “high” if the overall tract summary ranking value was greater than 0.70. The boundaries of the Census tract polygons were clipped to the residential parcels in Contra Costa County’s parcel dataset. This limited the extent of the tracts to areas that contain population, resulting in more accurate determination of the tracts that intersect hazard areas. For the exposure analysis, the hazards areas were intersected with the Census tract polygons. The percent of a given tract polygon intersected by a hazard area was calculated, and this percent was used to estimate the exposed population in high social vulnerability areas.

City of Concord Hazard Mitigation Plan Risk Assessment Methodology 7-4

7.3 SOURCES OF DATA USED

7.3.1 Building and Cost Data
Replacement cost values and detailed structure information derived from parcel and tax assessor data provided by Contra Costa County were loaded into Hazus. When available, an updated inventory was used in place of the Hazus defaults for critical facilities.

Replacement cost is the cost to replace the entire structure with one of equal quality and utility. Replacement cost is based on industry-standard cost-estimation models published in RS Means Square Foot Costs (RS Means, 2022). It is calculated using the RS Means square foot cost for a structure, which is based on the Hazus occupancy class (i.e., multi-family residential or commercial retail trade), multiplied by the square footage of the structure from the tax assessor data. The construction class and number of stories for single-family residential structures also factor into determining the square-foot costs.

7.3.2 Hazus Data Inputs
The following hazard datasets were used for the Hazus Level 2 analysis conducted for the risk assessment:
• Flood—The effective Digital Flood Insurance Rate Map (DFIRM) for the planning area was used to delineate flood hazard areas and estimate potential losses from the 1-percent-annual-chance and 0.2-percent- annual-chance flood events.
• Dam Failure—Dam failure inundation areas were downloaded from the California Department of Water Resources for the Mallard Reservoir, Lafayette, and Pine Creek Detention Dams. • Earthquake—Earthquake shake maps prepared by the USGS were used for the analysis of this hazard. Data from the California Geological Survey on National Earthquake Hazard Reduction Program soil types and liquefaction zones were also integrated into the Hazus model.

7.3.3 Other Local Hazard Data
Locally relevant information on hazards was gathered from a variety of sources. Frequency and severity indicators include past events and the expert opinions of geologists, emergency management specialists, and others. Data sources for specific hazards were as follows:
• Landslide—Susceptibility to deep-seated landslides data were provided by the California Geological Survey.

Areas categorized as very high susceptibility, high susceptibility, and medium susceptibility were used in the exposure analysis.
• Severe Weather—No GIS format severe weather area datasets were identified for the planning area. • Wildfire— No GIS format wildfire hazard area mapping was identified for the planning area.

7.3.4 Data Source Summary
Table 7-1 summarizes the data sources used for the risk assessment for this plan.

City of Concord Hazard Mitigation Plan Risk Assessment Methodology 7-5
Table 7-1. Hazus Model Data Documentation
Data Source Date Format
Parcels (included county tax assessor
information such as use code, year built,
and building square footage)
City of Concord 2022 Digital (GIS)
Building Outlines City of Concord 2022 Digital (GIS)
Building replacement (square foot) costs RS Means 2022 Digital (pdf) CA State dam breach inundation maps
(inundation boundaries and depth grids)
California Department of Water
Resources
2019 - 2021 Digital (GIS)
ShakeMap – Concord-Green Valley Fault
M6.8
USGS 2013 Digital (GIS)
ShakeMap – Haywired M7.05 USGS 2018 Digital (GIS)
ShakeMap – Mount Diablo Thrust M6.7 USGS 2017 Digital (GIS) NEHRP soils (VsMapV3_Geology) California Department of Conservation 2015 Digital (GIS) Liquefaction Susceptibility USGS (data provided by City of Concord) Unknown Digital (GIS) Digital Flood Insurance Rate Map (DFIRM) –
Contra Costa County effective 3/21/2017
FEMA 2017 Digital (GIS)
Susceptibility to deep-seated landslides California Geological Survey 2011 Digital (GIS) BART Stations City of Concord Provided 2022 Digital (GIS) City Offices City of Concord Provided 2022 Digital (GIS) EOC Shelters City of Concord Provided 2022 Digital (GIS) Fire Stations City of Concord Provided 2022 Digital (GIS) PGE Gas Facilities City of Concord Provided 2022 Digital (GIS) PGE Gas Valves City of Concord Provided 2022 Digital (GIS) Hospitals City of Concord Provided 2022 Digital (GIS)
Police Stations City of Concord Provided 2022 Digital (GIS) Schools City of Concord Provided 2022 Digital (GIS)
Electric Substations California Energy Commission Downloaded 2022 Digital (GIS) Local Bridges California Department of Transportation Downloaded 2022 Digital (GIS) Healthcare Facilities California Office of Statewide Health Planning and Development
Downloaded 2022 Digital (GIS)
State Highway Bridges California Department of Transportation Downloaded 2022 Digital (GIS) 2018 Contra Costa County Hazard
Mitigation Plan Critical Facilities Inventory
City of Concord 2018 Digital (GIS)

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

City of Concord Hazard Mitigation Plan Risk Assessment Methodology 7-6
• Mitigation measures already employed
• The amount of advance notice residents have to prepare for a specific hazard event These factors can affect loss estimates by a factor of two or more. Therefore, potential exposure and loss estimates are approximate and should be used only to understand relative risk.

8-1

8. DAM AND LEVEE FAILURE

8.1 GENERAL BACKGROUND

8.1.1 Definition and Classification of Dams
A dam is an artificial barrier that can store water, wastewater, or liquid-borne materials. Dams serve a variety of specialized functions including flood control, human water supply, livestock water supply, agricultural irrigation, energy generation, containment of mine tailings, recreation, or pollution control. Many dams fulfill a combination of these functions. They are an important resource in the United States. In California, dams are regulated by the State of California Division of Safety of Dams. Additional regulatory oversight of dams is cited in Chapter 6 and described in Appendix B.

The California Water Code (Division 3) defines a dam as any artificial barrier, together with appurtenant works, that does or may impound or divert water, and that either:
• Has a height of more than 6 feet and it impounds 50 acre-feet or more of water, or • Has a height of 25 feet or higher and impounds more than 15 acre-feet of water Dams can be classified according to their purpose, the construction material or methods used, their slope or cross- section, the way they resist the force of the water pressure, or the means used for controlling seepage. Materials used to construct dams include earth, rock, tailings from mining or milling, concrete, masonry, steel, timber, plastic, rubber, and combinations of these.

8.1.2 Causes of Dam Failure
Dam failure can cause massive destruction to the ecosystems and communities located downstream. Partial or full failure can occur as a result of one or a combination of the following reasons:
• Overtopping caused by floods that exceed the dam capacity (inadequate spillway capacity) • Prolonged periods of rainfall and flooding
• Deliberate acts of sabotage (terrorism)
• Structural failure of materials used in dam construction • Movement and/or failure of the foundation supporting the dam • Settlement and cracking of concrete or embankment dams • Piping and internal erosion of soil in embankment dams

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-2
• Inadequate or negligent operation, maintenance, and upkeep • Failure of upstream dams on the same waterway
• Earthquake (liquefaction/landslides)
Many dam failures in the United States have been secondary results of other disasters. The most common causes are earthquakes, landslides, extreme storms, equipment malfunction, structural damage, foundation failures, and sabotage.

Poor construction, lack of maintenance and repair, and deficient operational procedures are preventable or correctable by a program of regular inspections. Terrorism and vandalism are serious concerns that all operators of public facilities must plan for; these threats are under continuous review by public safety agencies.

8.1.3 Planning Requirements
State of California
All dams whose inundation areas may impact the planning area have emergency action plans (EAPs) on file. The EAPs must include the following (Cal OES 2023):
• Emergency notification flow charts
• Information on a four-step response process
• Description of agencies’ roles and actions in response to an emergency incident • Description of actions to be taken in advance of an emergency • Inundation maps
• Additional information such as revision records and distribution lists After the EAPs are approved by the state, the law requires dam owners to send the approved EAPs to relevant stakeholders. Local public agencies can then adopt emergency procedures that incorporate the information in the EAP in a manner that conforms to local needs, including methods and procedures for alerting and warning the public and other response and preparedness related items (Cal OES 2023).

Federal Energy Regulatory Commission
Dams that fall under the jurisdiction of the Federal Energy Regulatory Commission (FERC) also have specified planning requirements. FERC has the largest dam safety program in the United States. It cooperates with a large number of federal and state agencies to ensure and promote dam safety and, more recently, homeland security. FERC requires licensees to prepare emergency action plans and conducts training sessions on how to develop and test these plans. The plans are designed to serve as an early warning system if there is a potential for, or a sudden release of water from, a dam failure or accident to the dam. The plans include operational procedures that may be used, such as reducing reservoir levels and reducing downstream flows and procedures for notifying affected residents and agencies responsible for emergency management. These plans are frequently updated and tested to ensure that in emergency situations everyone knows what to do, thus saving lives and minimizing property damage.

FEMA Guidance for Flood Mapping
FEMA’s Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures is part of the National Dam Safety Program, a partnership of states, federal agencies, and other stakeholders formed to encourage

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-3
individual and community responsibility for dam safety. Under this program, states are responsible for regulating non- federal dams. The guidelines provide information for federal and state agencies, local governments, dam owners, and emergency management officials to use for reducing flood hazards and the resulting potential for economic damage and loss of life (FEMA 2022). It is a resource for developing state-specific guidelines for dam safety and as a reference manual for mapping dam breach inundation zones.

8.1.4 Rating Dam Hazards
Dam failure can be catastrophic to all life and property downstream. The Division of Safety of Dams has developed a hazard potential classification system for state-jurisdiction dams, as shown on Table 8-1. This system is modified from federal guidelines, which recommend three-tier classification. The California system adds a fourth hazard classification of “extremely high.” Dams classified as extremely high hazard may impact highly populated areas or critical infrastructure or have short evacuation warning times.

Table 8-1. State of California Downstream Hazard Potential Classification Hazard
Classification Potential Downstream Impacts on Life and Property Low No probable loss of human life and low economic and environmental losses. Losses are expected to be principally limited to the owner’s property.

Significant No probable loss of human life but can cause economic loss, environmental damage, impacts to critical facilities, or other significant impacts.

High Expected to cause loss of at least one human life.

Extremely
High
Expected to cause loss of at least one human life and result in an inundation area with a population of 1,000 or more.

Source: (Division of Safety of Dams 2021)

8.1.5 Levees
Levees are man-made structures, usually earthen embankments, designed and constructed to contain, control, or divert a flow of water in order to protect land from peak flood levels or to protect land that is below sea level.

The U.S. Army Corps of Engineers operates, maintains, and evaluates levees to determine if they meet accreditation requirements. Most levees are owned by local communities and flood control districts that must ensure proper operation and maintenance of the levee system as well (FEMA n.d.-a). Two types of levees are present in the San Joaquin-Sacramento River Delta area of Contra Costa County (2015-2016 Contra Costa County Grand Jury, 2016):
• Levees that are part of an authorized federal flood control project on the Sacramento-San Joaquin River Delta systems that deliver irrigation and drinking water are designated as “project” levees. The 385 miles of project levees are built to the highest level of flood protection standards, are maintained mainly by the County, and are inspected by the U.S. Army Corps of Engineers. • All other levees in the Delta are “non-project” or “local” levees. These levees, totaling 730 miles in length, are maintained by local reclamation districts.

The non-project levees incorporate modern techniques and materials as the reclamation districts work to bring the old agricultural levees up to current standards. As land has subsided and sea levels have risen, a lot of the land behind these levees is now 10 to 15 feet below sea level, making the efforts of continual improvements essential to avoid overtopping and consequent flooding.

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-4
A levee breach occurs when part of a levee gives way, creating an opening through which floodwaters may pass. A breach may occur gradually or suddenly. The most dangerous breaches happen quickly during periods of high water.

The resulting torrent can quickly swamp a large area behind the failed levee with little or no warning. When a levee system fails or is overtopped, severe flood damage can occur due to increased water surface elevation associated with levees and the resulting increase in water velocity.

Earthen levees can be damaged in several ways. For instance, strong river currents and waves can erode the surface.

Trees growing on a levee can blow over, leaving a hole where the root wad and soil used to be. Burrowing animals, such as the California ground squirrel, the salt marsh harvest mouse, or the western burrowing owl can create holes that enable water to pass through a levee. If severe enough, any of these situations can lead to a zone of weakness that could cause a levee breach. In seismically active areas, earthquakes and ground shaking can cause a loss of soil strength, weakening a levee and possibly resulting in failure. Seismic activity can also cause levees to slide or slump, both of which can lead to failure.

No levee provides protection from events for which it was not designed, and levees require maintenance to continue to provide the level of protection they were designed and built to offer. Maintenance responsibility belongs to a variety of entities including local, state, and federal government and private landowners. Well-maintained levees may obtain certification through independent inspections. Levees may not be certified for maintaining flood protection when the levee owner does not maintain the levee or pay for an independent inspection. The impacts of an un- certified levee include higher risk of levee failure. In addition, insurance rates may increase because FEMA identifies on Flood Insurance Rate Maps that the structures are not certified to protect from a 1-percent annual chance flood event (FEMA 2021).

8.1.6 Secondary Impacts
Dam and levee failure can cause severe downstream flooding, depending on the magnitude of the failure. Other potential secondary impacts of dam and levee failure are landslides around the reservoir perimeter, bank erosion on the rivers, and destruction of downstream habitat.

8.2 HAZARD PROFILE

8.2.1 Past Events
According to the 2018 California State Hazard Mitigation Plan, there have been nine dam failures in the state since 1950 (California Governor's Office of Emergency Services 2018). Overtopping caused two of the failures, and the others were caused by seepage or leaks. The historical record indicates that California has had about 45 failures of non-federal dams. The failures occurred for a variety of reasons, the most common being overtopping. Other reasons include shortcomings in the dams or an inadequate assessment of surrounding geomorphologic characteristics.

8.2.2 Location
List of High-Hazard Dams
According to the Corps’ National Inventory of Dams, there are 27 dams in Contra Costa County, four of which are in the vicinity of Concord or have projected inundation areas that may affect Concord in the event of a dam failure.

Figure 8-1 shows the dam locations. Key features are listed in Table 8-2.

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-5

Figure 8-1. High or Extremely High Hazard Dams with Potential to Affect the Planning Area

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-6
Table 8-2. Dams with Potential to Impact the City of Concord Lafayette Dam Mallard Dam Pine Creek Dam
Pine Creek
Detention Dam
National ID # CA00163 CA00838 CA00808 CA01252
Hazard Classa H S H S
Water Course Lafayette Creek Off-stream Pine Creek Pine Creek Owner East Bay Municipal
Utility District
Contra Costa
Water District
Contra Costa Flood Control and Water
Conservation District
Year Built 1929 1930 1956 1981
Dam Type Earth Earth Earth Gravity
Crest Length (feet) 1,200 11,000 320 232
Height (feet) 132 30 87 30
Storage Capacity (acre-feet) 4,250 3,113 225 320
Drainage area (sq. mi.) 1.34 0 4.36 10
Date Last Inspected December10, 2020 October 15, 2020 November 6, 2020 October 15, 2020 a. Hazard Class: H = High, S = Significant
Source: (U.S. Army Corps of Engineers 2020)
Dam Failure Inundation Mapping
A key element of EAPs required for dams in California is a map defining the potential downstream inundation should the dam fail. The Division of Safety of Dams approves inundation maps prepared by licensed civil engineers and submitted by dam owners for extremely high, high, and significant hazard dams and their critical appurtenant structures. Inundation maps approved by Division of Safety of Dams provide general information for emergency planning and are used to develop emergency action plans. Evacuation zones and timing are determined by local emergency managers who are responsible for specific evacuation planning.

Digital data indicating worst-case inundation areas for dams that affect the planning area were used for the dam failure risk assessment for this hazard mitigation plan. Dam inundation areas for which inundation mapping was available were combined into a single inundation area. The combined dam failure inundation area includes the following dams:
• Lafayette (extremely high hazard)
• Mallard Reservoir (high hazard)
• Pine Creek Detention (high hazard)
This combined area is shown in Figure 8-2.

Levee Locations
The U.S. Army Corps of Engineer’s National Levee Database lists three project levees protecting the City of Concord, all of which are included in the Corps’ levee program. Summary information is listed in Table 8-3.

UV242
UV4
UV4
§¨¦680
Treat Blvd
Clayton Rd
Willow Pass Rd
Kirker Pass RdMonument Blvd
Oak Grove Rd
Port Chicago Hwy
Cowell Rd
Galindo St
Concord Blvd
Ygnacio Valley Rd
Mallard
Reservoir
Concord

DAM FAILURE INUNDATION AREAS
Data Sources
CA Department of Water Resources
CIty of Concord
0 1 2
Miles
4 Mallard Reservoir Inundation Area
Lafayette and Pine Creek Detention
Inundation Area
Figure 8-2

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-8
Table 8-3. Project Levees in Protecting the City of Concord Levee Name Levee Owner
Segment Length
(miles)
Corps Program
Levee
Walnut Creek and Grayson Creek – right bank Contra Costa County FCWCD 2.88 Yes Walnut Creek and Grayson Creek – left bank Contra Costa County FCWCD 1.49 Yes Walnut Creek and Clayton Valley Drain – right bank Contra Costa County FCWCD .56 Yes Source (U.S. Army Corps of Engineers n.d.)

8.2.3 Frequency
Large-scale dam failure events are infrequent and usually coincide with events that cause them, such as earthquakes and excessive rainfall. A Stanford University study found an average of about 10 dam failures per year nationwide over a period of record from 1848 through 2017 (Stanford University 2018).

All dams face a “residual risk” of failure, which represents the risk that conditions may exceed those for which the dam was designed. For example, dams may be designed to withstand a probable maximum precipitation, defined as “the maximum depth of precipitation at a location for a given duration that is meteorologically possible” (Sarkar and Maity 2020). The chance of a precipitation event of a greater magnitude than that represents residual risk for such dams. This represents a theoretical probability of future occurrence for a dam failure event, though the probability of an event exceeding the assumed maximum is not generally calculated as part of dam design.

8.2.4 Severity
Dam failure can be catastrophic to all life and property downstream. California’s hazard ratings, as described in Table 8-1 describe the potential consequences of dam failure based on hazard ratings. For the dams assessed in this plan, with hazard ratings of extremely high and high, complete failure is expected to cause loss of at least one human life and inundate an area with a population of 1,000 or more or critical facilities whose inundation poses a significant threat to public safety.

The Stanford University study of dam failures nationwide found that many failures were of small dams, with limited flooding or downstream impact. More than 96 percent of the failures did not result in life-safety consequences or significant property damage (Stanford University 2018).

8.2.5 Warning Time
The potential for personal injury or loss of life in the event of a dam failure is affected by the amount of warning time and the capacity of evacuation routes available to those living in inundation areas. Warning time depends on the cause of the failure. In case of extreme precipitation, evacuations can be implemented with sufficient time. In the event of a structural failure due to earthquake, there may be no warning time. The USGS Earthquake Hazards Program has several dam-safety related earthquake programs, including dam-specific earthquake monitoring programs in California to help monitor safety concerns following seismic events.

A dam’s structural type affects warning time. Earthen dams do not tend to fail completely or instantaneously. Once a breach is initiated, discharging water erodes the breach until the reservoir is empty or the erosion stops. Concrete dams also tend to begin with a partial breach. The time of breach formation ranges from a few minutes to a few hours (U.S. Army Corps of Engineers 2014).

City of Concord Hazard Mitigation Plan Dam and Levee Failure 8-9

8.3 EXPOSURE AND VULNERABILITY
Risk assessment findings for dam failure are limited to estimates of exposure. Because the analysis found very limited exposure to the dam failure hazard, no vulnerability assessment was conducted. Appendix D shows exposure results broken down by Council voting district. Summary findings for the overall planning area are as follows:
• No residential population is exposed to the mapped dam failure inundation hazard. • Eight buildings are exposed—two commercial and six industrial—with an estimated total replacement value of $192 million (structure and contents value).
• One critical facility is within the mapped dam failure inundation area.

8.4 FUTURE TRENDS IN DEVELOPMENT
Dam failures are low-probability, high-consequence events. Because of this, it is not typically practical for local governments to regulate new development in dam failure inundation areas. Land use will be directed by the City of Concord General Plan and zoning ordinance adopted under state law. The safety element of the General Plan establishes standards and plans for the protection of the community from hazards. Dam failure is currently not addressed as a stand-alone hazard in the safety element, but flooding is. The City of Concord has established comprehensive policies regarding sound land use in identified flood hazard areas. Most of the areas vulnerable to the more severe impacts from dam failure intersect the mapped flood hazard areas. Flood-related policies in the general plan will help to reduce the risk associated with the dam failure hazard for all future development in the City. Any new development outside of a flood hazard area will most likely not include provisions that would mitigate the impacts from a dam failure.

The probability of flooding associated with changes in dam operational parameters in response to extreme rainfall events is higher than the probability of dam failure. Dam designs and operations are based on hydrographs from historical records. If these hydrographs change significantly over time due to effects of climate change, current dam designs and operations may become overwhelmed. Specified release rates and impound thresholds may have to be changed, which could result in increased discharges downstream of these facilities, thus increasing probability and severity of inundation

8.5 SCENARIO
An earthquake in the region could lead to liquefaction of soils around a dam. This could occur without warning during any time of the day. Human activity such as a terrorist attack also could trigger a catastrophic failure of a dam that impacts the planning area.

8.6 ISSUES
The most significant issue associated with dam failure involves the properties and populations in the inundation zones. Flooding as a result of a dam failure would significantly impact these areas. There is often limited warning time for dam failure. These events are frequently associated with other natural hazard events such as earthquakes, landslides or severe weather, which limits their predictability and compounds the hazard. Important issues associated with dam failure hazards include the following:
• California’s AB 2800 enacts legislation that will require engineers and climate scientists to collaborate to help the state design and build infrastructure that will withstand the unavoidable impacts of a changing climate.