2017/11/28 City Council Resolution 2017-139RESOLUTION NO. 2017-139
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF ROHNERT PARK
ADOPTING THE 2017 LOCAL HAZARD MITIGATION PLAN
WHEREAS, Sonoma County is subject to various earthquake related hazards such as
ground shaking, liquefaction, land sliding, and fault surface rupturing; and
WHEREAS, Sonoma County is subject to various weather related natural hazards
including wildfires, floods, and droughts; and
WHEREAS, the City of Rohnert Park seeks to maintain and enhance both a disaster
resistant city and region by reducing the potential loss of life, property damage, and
environmental degradation from natural disasters while accelerating economic recovery from
those disasters; and
WHEREAS, the Federal Disaster Mitigation Act of 2000 requires all cities, counties,
and special districts to adopt a Local Hazard Mitigation Plan (LHMP) to receive disaster
mitigation funding from FEMA and to update such LHMP every five years to maintain
eligibility; and
WHEREAS, the City's previously adopted LHMP, the Association of Bay Area
Government's report entitled Taming Natural Disasters, adopted in 2012 has now expired; and
WHEREAS, the City has undergone an extensive planning and outreach process, and
prepared the draft report entitled "City of Rohnert Park — 2017 Local Hazard Mitigation Plan";
NOW, THEREFORE, BE IT RESOLVED that the City Council of the City of Rohnert
Park adopts the City of Rohnert Park 2017 Local Hazard Mitigation Plan as its Local Hazard
Mitigation Plan.
DULY AND REGULARLY ADOPTED this 28th day of November, 2017.
CITY OF ROHNERT PARK
ake Ma[[-enzie, Mayor
ATTEST:
Caitlin Saldanha, Deputy City Clerk
Attachment: Local Hazard Mitigation Plan
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CITY OF ROHNERT PARK | 130 AVRAM AVE, ROHNERT PARK, CA 94928
City of Rohnert Park - 2017
Local Hazard Mitigation Plan
DRAFT
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Table of Contents
Introduction ................................................................................................................................................................................................5
Purpose .....................................................................................................................................................................................................5
Compliance ...............................................................................................................................................................................................6
Mitigation Goals and Priorities ................................................................................................................................................................8
Planning Process ........................................................................................................................................................................................9
FEMA Element A: Planning Process .......................................................................................................................................................9
Scoping and Kick-Off ..............................................................................................................................................................................9
Schedule and Process .............................................................................................................................................................................10
Team Members .......................................................................................................................................................................................11
Public Outreach and Stakeholder Involvement Opportunities ...............................................................................................................12
Review of Existing Plans and Technical Information ............................................................................................................................13
Physical Setting and Community Profile ...............................................................................................................................................14
Physical Setting ......................................................................................................................................................................................15
Historic and Current Conditions ............................................................................................................................................................15
Community Profile .................................................................................................................................................................................15
Land Use ................................................................................................................................................................................................17
Downtown Development ........................................................................................................................................................................19
Housing Development ............................................................................................................................................................................20
Population Data ......................................................................................................................................................................................22
Economic Trends ....................................................................................................................................................................................25
Critical Facilities and Populations ..........................................................................................................................................................26
Hazard Identification, Analysis, and Assessment ................................................................................................................................35
FEMA Element B: Hazard Identification and Risk Assessment ............................................................................................................35
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Hazard Prioritization ..............................................................................................................................................................................37
Primary Hazard Profiles .........................................................................................................................................................................39
Earthquake (Shaking).....................................................................................................................................................................41
Earthquake (Liquefaction) .............................................................................................................................................................41
Flooding (Local) ............................................................................................................................................................................45
Flooding (FEMA) ..........................................................................................................................................................................45
Drought ..........................................................................................................................................................................................53
Wildfire/Wildland-Urban Interface Fire ........................................................................................................................................58
Minor or Secondary Hazard Profiles ......................................................................................................................................................63
Hazardous Materials ......................................................................................................................................................................63
Landslide ........................................................................................................................................................................................64
Dam Inundation .............................................................................................................................................................................67
Earthquake Faulting .......................................................................................................................................................................68
Summary of Vulnerabilities ...................................................................................................................................................................70
Vulnerability Analysis ............................................................................................................................................................................71
Social Vulnerability Analysis .................................................................................................................................................................80
Mitigation and Adaptation Strategy ......................................................................................................................................................81
FEMA Element C: Mitigation Strategy .................................................................................................................................................81
Mitigation Goals .....................................................................................................................................................................................82
Mitigation Activities ..............................................................................................................................................................................86
Capabilities Assessment .......................................................................................................................................................................101
Plan Maintenance and Adoption Process ............................................................................................................................................107
FEMA Element D: Plan Review, Evaluation, and Implementation .....................................................................................................107
Coordinating Group ..............................................................................................................................................................................107
Plan Update Process .............................................................................................................................................................................108
Adoption and Implementation Process ................................................................................................................................................108
Technical Appendices and Documents ................................................................................................................................................110
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List of Tables
Table 2.1: Potential Housing Growth by Development Area ....................................................................................................................21
Table 2.2: Population and Housing Data Comparison...............................................................................................................................22
Table 2.3: Race and Ethnicity Data Comparison .......................................................................................................................................23
Table 3.1: Critical Facilities .......................................................................................................................................................................26
Table 3.2: Parks, Recreation Facilities, and Open Space ..........................................................................................................................28
Table 3.3: Infrastructure.............................................................................................................................................................................29
Table 3.5: Vulnerable Populations .............................................................................................................................................................33
Table 3.4: Evaluated Hazards ....................................................................................................................................................................36
Table 3.5: Hazard Criteria Ranking Scores and Weighing Factors ...........................................................................................................37
Table 3.6: Scores and Threat Levels for Included Hazards .......................................................................................................................38
Table 4.1: Vulnerability Analysis ..............................................................................................................................................................71
Table 4.2: Infrastructure Vulnerability and Exposure ...............................................................................................................................77
Table 4.3: Community-Wide Social Vulnerability Metrics .......................................................................................................................80
Table 5.1: STAPLE/E Criteria ...................................................................................................................................................................84
Table 5.2: Mitigation Actions ....................................................................................................................................................................86
Table 5.3: Available Resources ...............................................................................................................................................................100
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APPENDICES
Appendix A – Acronyms, Abbreviations, and Glossary
Appendix B – Planning Process Documents
Appendix C – Mapping
Appendix D – 2010 ABAG Annex
Appendix E – Supplemental Materials
Appendix F – Plan Review
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INTRODUCTION
Purpose
No one is free of natural hazards which may vary across landscapes and time. With
Natural hazards comes disasters that can cause loss of life, and damage to our built
environment resulting in depletion of the community’s economic, social, and
environmental well-being. Resiliency and adaptation is crucial, because a
community must have sustained ability to use available resources to respond to,
withstand and recover from adverse situations. It is the responsibility of the City to
protect the health, safety, and welfare of our residents. This LHMP sets in stone the
community’s activities that address preparedness, response, recovery and
mitigation.
The City of Rohnert Park Local Hazard Mitigation Plan:
• Meets the requirements of federal assistance grant programs, including FEMA’s Hazard Mitigation Grant Program (HMGP)
and Pre-Disaster Mitigation (PMD) funding.
• Works in conjunction with other plans, including the City’s General Plan and the City’s Emergency Management Plan.
• Establishes a basis for coordination and collaboration among community entities such as private and public agencies, key
stakeholders, and residents to provide for the fullest amount of transparency.
• Identifies and prioritizes future mitigation projects.
The term “Hazard” is defined by FEMA as “any event or physical condition that has the potential to cause fatalities, injuries, property
damage, infrastructure damage, agricultural losses, damage to the environment, interruption of business, or other types of harm or loss.
Hazard Mitigation is defined as “any sustained action taken to reduce or eliminate long term risk to human life and property from
natural, human-caused, and technological hazards and their effects.”
A hazard mitigation plan should not be confused with emergency response or preparedness plans that are focused on being ready
and responding when a hazard or disaster event occurs and may include such actions as providing emergency response, equipment,
food, shelter, and medicine. However, hazard mitigation and emergency preparedness go hand-in-hand and are part of the City’s
multi-pronged approach to minimizing personal injury and property damage from Hazards in the residential and commercial areas. It
compliments other planning documents and regulatory authorities governing pre-disaster land use planning and post-disaster response
and recovery.
Figure 1.1: Sonoma County flooding
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Compliance
FEMA Regulations
The Federal Emergency Management Agency’s (FEMA) mission:
“to support our citizens and first responders to ensure that as a nation we work
together to build, sustain and improve our capability to prepare for, protect against,
respond to, recover from and mitigate all hazards.”
Hazard mitigation planning is directed by the Robert T. Stafford Disaster and Relief and
Emergency Assistance Act (Stafford Act), as amended by the Disaster Mitigation Act of
2000 (DMA 2000). DMA 2000 amended the Stafford Act to require state, local, and tribal
governments to develop and submit to FEMA a mitigation plan that outlines processes for
identifying the natural hazards, risks, and vulnerabilities of the jurisdiction. Plan approval
by FEMA is a prerequisite to receiving federal hazard mitigation grant funds (see 42 USC
Section 5165(a)).
To implement the mitigation planning requirements of the Stafford Act, FEMA
promulgated 44 Code of Federal Regulations (CFR) Part 201, the federal regulations
governing the planning process, plan content, and the process for obtaining approval of the
plan from FEMA. The planning requirements set forth in the CFR, including plan revision
requirements, are identified through the FEMA Regulation Checklist in the Local
Mitigation Plan Review Tool. Local Mitigation Plans must be updated once every five years in order to continue to be eligible for
FEMA hazard mitigation project grant funding. Specifically, 44 CFR 201.6(d)(3) reads:
A local jurisdiction must review and revise its plan to reflect changes in development, progress in local mitigation efforts, and
changes in priorities, and resubmit it for approval within (5) years in order to be eligible for mitigation project grand funding.
For FEMA approval, all Elements including sub-element must be met with current information. The Rohnert Park Local Hazard
Mitigation Plan (LHMP) complies with the DMA 2000, Federal Register 44 CFR Parts 201 and 206, Section 322, Mitigation
Planning. This law, as of November 1, 2004, requires local governments to develop and submit hazard mitigation plans as a condition
of receiving Hazard Mitigation Grant Program (HMGP) and other mitigation project grants.
Figure 1.2: LHMP Handbook
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State of California
In addition to the requirements listed above, the State of California has also enacted revisions to California Government Code Sections
8685.9 and 65302.6 (commonly known as Assembly Bill [AB] 2140 [Chaptered 2006]) which addresses the requirements to have a
local hazard mitigation plan. Excerpts of these government code sections are included below.
California Government Code Section 8685.9:
Notwithstanding any other provision of law, including Section 8686, for any eligible project, the state share shall not exceed 75
percent of total state eligible costs unless the local agency is located within a city, county, or city and county that has adopted a local
hazard mitigation plan in accordance with the federal Disaster Mitigation Act of 2000 (P.L. 106-390) as part of the safety element of
its general plan adopted pursuant to subdivision (g) of Section 65302. In that situation, the legislature may provide for a state share of
local costs that exceeds 75 percent of total state eligible costs.
California Government Code Section 65302.6:
(a) A city, county, or a city and county may adopt with its safety element pursuant to subdivision
(g) of Section 65302 a local hazard mitigation plan (HMP) specified in the federal Disaster
Mitigation Act of 2000 (Public Law 106-390). The hazard mitigation plan shall include all of the following elements called for
in the federal act requirements:
(1) An initial earthquake performance evaluation of public facilities that provide essential services, shelter, and critical
governmental functions.
(2) An inventory of private facilities that are potentially hazardous, including, but not limited to, multiunit, soft story, concrete
tilt-up, and concrete frame buildings.
(3) A plan to reduce the potential risk from private and governmental facilities in the event of a disaster.
(b) Local jurisdictions that have not adopted a local hazard mitigation plan shall be given preference by the Office of Emergency
Services in recommending actions to be funded from the Pre-Disaster
Mitigation Program, the Hazard Mitigation Grant Program, and the Flood Mitigation Assistance
Program to assist the local jurisdiction in developing and adopting a local hazard mitigation plan, subject to available funding from
the Federal Emergency Management Agency.
This LHMP includes the information required by California Government Code Sections 8685.9 and 65302.6.
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Plan Use
Individual components of the LHMP provide information and resources to assist citizens and city staff in comprehending the potential
hazard related issues facing the City of Rohnert Park. The structure of the plan is intended to enable users to quickly and easily access
and understand each section as necessary. The structure allows the City of Rohnert Park to assess and update sections with new and
additional data as it becomes available. This is designed to increase the ease of the updating process – resulting in a more practical and
relevant plan.
Mitigation Goals and Priorities
The City of Rohnert Park established LHMP mitigation priorities and goals as a component of the planning process in order to guide
the development of a thorough plan. The goals were developed by the planning team and drawn from the previous LHMP and the
City’s General Plan. The mitigation goals and priorities for the LHMP are:
1. Implement the Local Hazard Mitigation Plan to increase Rohnert Park’s
level of preparation for potential disasters and to minimize the impacts
associated with natural and man-made hazards.
2. Identify strategies and tools to facilitate community disaster and hazards
awareness and education.
3. Provide for the safety of Rohnert Park citizens by maintaining efficient, well-
trained, and adequately equipped City personnel.
4. Encourage a disaster-resistant City and surrounding area by reducing the
potential for loss of life, property damage, and environmental degradation from
disasters and hazards.
5. Reduce the vulnerability of public and private facilities and infrastructure to
the effects of earthquakes, flooding, and drought.
6. Promote conditions and strategies that will accelerate the capacity for
physical and economic recovery from disasters and hazards.
Figure 1.3: Mitigation Cycle
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PLANNING PROCESS
The Rohnert Park LHMP Planning process was defined from the get-go by the community and its needs. Bringing together local
officials, stakeholders and the public in a community-driven planning process to develop the plan also helps build the community’s
overall hazard mitigation program. The LHMP is the written record, or documentation, of the planning process. This is why some of
the plan requirements ask for a “discussion” or “description” of generally what must be documented in the plan, rather than specify
exactly how it must be done. Element A dictates the requirements for what should be included in the Planning Process.
FEMA Element A: Planning Process
• A1. Does the Plan document the planning process, including how it was prepared and who was involved in the process for each
jurisdiction? 44 CFR 201.6(c)(1)
• A2. Does the Plan document an opportunity for neighboring communities, local and regional agencies involved in hazard
mitigation activities, agencies that have the authority to regulate development as well as other interests to be involved in the
planning process? 44 CFR 201.6(b)(2)
• A3. Does the Plan document how the public was involved in the planning process during the drafting stage? 44 CFR 201.6(b)(1)
and 201.6(c)(1)
• A4. Does the Plan document the review and incorporation of existing plans, studies, reports, and technical information? 44 CFR
201.6(b)(3)
• A5. Is there discussion on how the community(ies) will continue public participation in the plan maintenance process? 44 CFR
201.6(c)(4)(iii)
• A6. Is there a description of the method and schedule for keeping the plan current (monitoring, evaluating and updating the
mitigation plan within a 5‐year cycle)? 44 CFR 201.6(c)(4)(i)
Scoping and Kick-Off
Planning for the City of Rohnert Park’s Local Hazard Mitigation Plan can be traced back to the Summer of 2016 when the City
became aware that the 2010 Association of Bay Area Governments and accompanying Rohnert Park specific annex had expired. A
review of available literature including FEMA and State guides was commenced. The team initially assembled in late September with
an official initial kick-off meeting held on October 5, 2016. The team was primarily composed of City staff, specifically members of
the Development Services Department. Additional team members from the Administrative Unit, Public Works, and Public Safety
were also included. An ambitious scope of work was developed. While the general outline of the scope was followed in the
preparation and completion of the plan, the overall timeline did get extended.
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Schedule and Process
Meetings and events were held on the following dates:
• October 5, 2016 – Team Meeting: discussed
LHMP process and team member roles; began
preparation of the public involvement campaign.
• October 20, 2016 – Team Meeting: reintroduced
project with more team members, refined plan
for public engagement
• November 2, 2016 – Community Open House
and Presentation: open house focused on
emergency preparedness followed by
presentation and Q&A session about the LHMP.
• November 10, 2016 – Planning Commission:
provided update to planning commissioners on
project and solicited their ideas and feedback
• November 16, 2016 – Team Meeting: recap of activities and steps to date, mapping refinement, risk assessment and critical
facilities inventory
• December 9, 2016 – Team Meeting: mapping updates and mitigation goal setting exercise
• January 10, 2017 – Team Meeting: discussed further mitigation goals and activities, discussed critical facilities and
vulnerabilities
• January 31, 2017 – Team Meeting: draft mitigation measures and activities
• August 31, 2017 – Team Meeting: update on draft and current status of tasks, preliminary discussions regarding further
outreach
• September 14, 2017 – Team Meeting: review draft and updated completion timeline, refine plans for public outreach
• September 20, 2017 – Community Open House and Presentation: present draft to public during open house
• TBD, 2017 – Presentation to Sonoma County Area LHMP Task Force
• November 1, 2017 – Planning Commission
• November 28, 2017 – City Council
Figure 1.4: November 2016 Community Open House
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Team Members
The planning team for the LHMP was made of various city staff members representing a cross-section of relevant departments within
the City of Rohnert Park. Team members brought a variety of strengths and backgrounds to the group.
• Mary Grace Pawson, Director of Development Services – Provided overall guidance and supervision for the team and project.
• Jeff Beiswenger, Planning Manager, Development Services – Served as the primary point person in terms of Planning
Documents.
• Zach Tusinger, Planner II, Development Services – Overall
project manager, responsible for coordination, plan assembly,
and drafting.
• Jay Bradford, Building Official, Development Services –
Technical advisor regarding building standards and assessment
of city facilities.
• Caitlin Saldanha, Deputy City Clerk – Administration liaison.
Responsible for community outreach coordination.
• Marc Bautista, Environmental Coordinator (until March 2017) –
Contributed information regarding flooding and infrastructure.
• Nick Bennett, Environmental Coordinator (from August 2017) –
Provided supplemental information regarding flooding.
• Jim Thompson, Fire Marshal – Served as Public Safety liaison
and provided technical expertise regarding preparedness and
hazards.
• Jahfer Aguirre, GIS Analyst – Synthesized data and prepared
maps and exhibits for outreach events, analysis, and the plan
itself.
• Bonnie Betts, Planning Intern, Development Services – Created the plan template, and contributed to plan and appendices
preparation.
Figure 1.5: Rohnert Park City Hall
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Public Outreach and Stakeholder Involvement Opportunities
Multiple opportunities for public participation and stakeholder input
were offered throughout the planning, drafting, and approval processes.
The planning team held an event at the Rohnert Park-Cotati Library on
the evening of November 2, 2016. This was an opportunity for the
team to present some of its initial findings and ideas (as well as draft
components of the plan – primarily maps) to citizens and other
interested stakeholders. The team felt like this was a great opportunity
to invite other relevant departments and agencies to be available with
information and materials.
The first thirty minutes of the event were geared as an open house with
various booths, many focused on safety, emergency preparedness, and
resiliency. Booths were run by Sonoma-Marin Area Rapid Transit
(SMART), The Fire & Emergency Services Department of Sonoma
County -- Sonoma County
Alerts (SoCo Alerts), the
Rohnert Park Pet Shelter, the
American Red Cross, The Rohnert Park Department of Public Safety, and The Rohnert
Park Department of Public Works (to share information about their sandbagging program).
The remaining hour of the event was reserved for a presentation by the planning team as
well as a question and answer session, were community members provided initial
feedback and reactions to the planning process. A copy of the PowerPoint, advertising
materials, and handout are included in the Appendix. Much time was spent at the meeting
discussing the differences between emergency preparedness and response, and mitigation
Earthquakes were a primary concern of the residents who attended. The memory of the
2014 Napa earthquake was still fresh in everyone’s minds, and while there was not any
significant damage in Rohnert Park from that earthquake, the shaking was felt within the
City.
Figure 1.6: Community Meeting Flyer
Figure 1.7: Resiliency Concept
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Public Review Draft
On September 20, 2017, the City of Rohnert Park made available the public review draft of the Rohnert Park LHMP. The completed
draft was released to the general public for review and comment for a period of more than 30 days. Letters were sent to relevant
stakeholders and area agencies letting them know that the draft was available and directing them to an electronic copy for their review
and comment. Physical copies of the document were placed at the public counter in Development Services, with the Department of
Public Safety, and with the City Clerk.
On the same day, the City held a community meeting to present the general outcomes of the planning process, to discuss mitigation
goals and activities, to solicit additional feedback from members of the public, and to describe the next steps in the plan approval and
adoption process.
Review of Existing Plans and Technical Information
Taming Natural Hazards – Association of Bay Area Governments (ABAG) Multi-
Jurisdictional Local Hazard Mitigation Plan for the San Francisco Bay Area 2010
City of Rohnert Park - Annex to 2010 ABAG Plan
City of Rohnert Park Emergency Management Plan 2012
City of Rohnert Park General Plan 2020, 8th Edition
Sonoma County Hazard Mitigation Plan 2016
Figure 1.8: Emergency Management Plan
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PHYSICAL SETTING & COMMUNITY PROFILE
Physical Setting
Rohnert Park is located in central Sonoma County along US 101. It is the county’s third
largest city. The Pacific Ocean to the west with its cool marine air, and the warm Sonoma
Valley to the east combine to create a mild climate. Rohnert Park lies within the Cotati
Valley, with coastal hills to the west and the Sonoma Mountains to the east. Sonoma State
University sits just outside Rohnert Park’s eastern boundary. Rohnert Park is comprised of
approximately 6.9 square miles and with an elevation of 105 feet above sea level. The
City has a population of about 40,971 people, based on 2010 census information.
Rohnert Park was founded as a master-planned community on the former site of the
Rohnert Park Seed Farm. Thoughtfully designed for families, bikeways, and walkways
connect its tree-lined boulevards. Several creeks run into the city from the eastern
ridgeline. The city is surrounded by farms and grazing land.
Rohnert Park is located in the Santa Rosa-Petaluma Valley where the underlying geologic
structure is characterized by sediments deposited by streams on floodplains, alluvial deposits, and basins. Overall, general geologic
conditions, slopes, and soils do not vary significantly from one part of the city to another.
There are no known active faults within Rohnert Park. The Healdsburg-
Rodgers Creek fault zone lies approximately 5 miles to the east of the city.
The San Andreas Fault System is located approximately 15 miles west of
the city. Secondary seismic hazards that could affect Rohnert Park include
ground-shaking, liquefaction, and ground settlement.
Elevations range between 230 feet above mean sea level northeast of the
city to 90 feet above mean sea level on the western boundary of the city.
Given the relatively flat topography and the nature of soils, there is little
risk of mudslides, landslides, or erosion in the immediate Rohnert Park
area. Soil liquefaction has the potential to impact the Rohnert Park area
during a seismic event. Soils underlying almost the entire area within the
city exhibit moderate susceptibility to liquefaction (City of Rohnert Park
Emergency Management Plan 2012).
Figure 2.1: Rohnert Park Location
Figure 2.2: Rohnert Park US 101 Sign
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Community Profile
When gathering data regarding the community profile of Rohnert Park, staff looked towards the 2016 Rohnert Park Local Economic
Profile. This document was published by The Sonoma County Economic Development Board (EDB), in partnership with the Sonoma
County Workforce Investment Board (WIB), the City of Rohnert Park, and the Rohnert Park Chamber of Commerce. This document
offers projections through 2020 that is useful when looking at economic, and social trends.
Historical Context
Beginning in the fall of 1954 a plan for a new town
north of Cotati in Sonoma County was beginning to
emerge. The core of the plan was the "Neighborhood
Unit" concept. The plan was a modification of
Pennsylvania's Levittown. It provided that each
neighborhood would consist of 200-250 homes centered
on a 10-acre school site and 5 -acre pool-park site. No
child would have to walk more than 1/3 of a mile to
school; the school would be the nucleus of a cohesive
community. The commercial and industrial development
would be large enough and diverse enough to support
the entire community. Eight such subdivisions would
constitute a city of 30,000 people. With planned pools,
parks, and service the city would be a "country club for
the working class".
On August 28, 1962, Rohnert Park was officially
incorporated: 1,325 acres, housing an estimated 2,775
persons. It was the fourth largest city in Sonoma County
and the first town to incorporate since 1905.
Since 1962, Rohnert Park has grown incrementally into a town of over 40,000 people across numerous neighborhood sections (see
Figure 2.4). Today, Rohnert Park is also the home for Sonoma State University, and is the gateway for Graton Resort & Casino.
Figure 2.3: Rohnert Park Aerial Circa 1960s.
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Figure 2.4: Rohnert Park Neighborhood Section Map
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Existing Land Use and General Plan
Existing land use information was taken from the Rohnert Park
General Plan. Specific Details came from the Land Use Element,
Specific Plans, and the adopted Zoning Map. The documents
used to implement the General Plan are the zoning code
inclusive of the various specific plans.
The Rohnert Park General Plan is a document required by State
law and adopted by the City Council that is a comprehensive,
long-term plan for the physical development and growth of the
city. It is the city's "constitution" for development; the
framework within which decisions on how to grow, provide
public services and facilities and protect and enhance the
environment are made.
The land use framework of the General Plan is embodied in the
General Plan Diagram, a graphic representation of the themes
and policies in the Plan. The General Plan Diagram designates
the proposed general location, distribution, and extent of land
use throughout the City.
The Planning Division is responsible for regularly updating the
City's General Plan Housing Element. The purpose of the
Housing Element is to make adequate provisions for the existing
and projected housing needs of all economic segments of the
community and to determine how the city will meet its fair share
of regional housing needs. The California Department of
Housing and Community Development has found that the most
recent update, adopted by the City Council in November of
2014, is in full compliance with State Housing Element Law. Figure 2.5: Rohnert Park General Plan Map
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Specific Plan and Other Areas
Specific Plans
A Specific Plan is a tool for the systematic implementation of the
General Plan. It effectively establishes a link between implementing
policies of the General plan and the individual development proposals in
a defined area. A Specific Plan may be as general as setting forth broad
policy concepts, or as detailed as providing direction to every facet of
development from the type, location and intensity of uses to the design
and capacity of infrastructure, from the resources used to finance public
improvements to the design guidelines of a subdivision.
Planned Development
The Planned Development (P-D) zoning district is intended to
accommodate a wide range of residential, commercial and industrial land
uses, which are mutually-supportive and compatible with existing and
proposed development on surrounding properties. P-D zoning districts
shall encourage the use of flexible development standards designed to
appropriately integrate a project into its natural and/or man-made setting
and shall typically be intended for projects that provide for a mix of land
uses to serve identified community needs. Furthermore, the P-D zoning
process may be used to implement the various specific plans adopted by
the city. Once established, the P-D zoning district becomes, in effect the
zoning for the area within its respective boundaries.
Priority Development Area Plan
Priority Development Areas, known as PDAs, are areas within existing
communities that city or county governments have identified and
approved for future growth. PDAs are accessible by one or more transit
services and are often located near established job centers and shopping
districts. Figure 2.6: Rohnert Park Development Areas
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Downtown Development Trends – Priority Development Area Plan
Creating a Vision for Central
Rohnert Park, in March 2016, the
City Council adopted the Central
Rohnert Park, Priority
Development Area Plan, along with
related General Plan and Zoning
Ordinance Updates. The plan covers
an approximately 330-acre
developed area of the city, roughly
centered along Rohnert Park
Expressway and State Farm Drive.
The plan features the creation of a
new Downtown District – approximately 50 acres in size, to create a hub of
activity within Central Rohnert Park. The downtown is envisioned to include a
vibrant mix retail, office and residential uses, centered at the intersection of
Rohnert Park Expressway and State Farm Drive. A key destination in
downtown will be the new train platform for the SMART train, which recently
completed testing and has entered full revenue service.
In addition to the new Downtown, the Central Priority Development Area Plan
will help incentive the construction of the following development over the next
20 or so years: over 800 residential units (concentrated within the one-half mile
radius of the SMART rail station); up to 450,000 square feet of retail and
services; up to 200,000 square feet of new office facilities; up to 60,000 square
feet of public buildings; up to 130,000 square feet of light industrial uses; and
8.5 acres of public parks and a comprehensive network of bicycle and walking
pathways.
Figure 2.8: New Construction
Figure 2.7: Central Rohnert Park PDA
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Housing Development
Over the last five years (2012-2016) a total of 1,753 new housing
units have received final discretionary approvals. The bulk of these
are planned to be constructed in the University District. Over that
same period 506 units were included in Final Map approvals. The
number of building permits approved over the last five years for
new housing totals 464. The bulk of those permits have been issued
in either the Stadium Lands area or the University District.
Building Permits for model homes in Southeast Rohnert Park are
expected to begin being issued before the end of 2017. Additional
multi-family developments have been approved on both sides of
Highway 101.
Figure 2.10: New Housing in the University District Figure 2.9: Recent Housing Development
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Potential Housing Growth
Table 2.1: Potential Housing Growth by Development Area
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Population Data
2010 2015
Total Population 40,971 41,651
Male 19,793 19,221
Female 20,728 22,430
Total Housing Units 16,000 16,424
Median Household Income $51,942 $58,719
Median House Value $300,000 $511,000
Source all: Bay Area Census 2010, ACS 2015, & 2016 Rohnert Park: Local Economic Profile
When looking at potential population growth and change as we move
closer to the year 2020, the population bracket of 65 and older is expected
to increase the greatest amount by 2020. While more people are moving
into the age of retirement this is creating a decrease in individuals 10-24
and 45-64 between 2015 and 2020.
Table 2.2: Population and Housing Data Comparison
Figure 2.11: Population Comparison
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Race and Ethnicity Data
Race and Ethnicity Population
(2010)
Percentage of Population
(2010)
Population
(2015)
Percentage of Population
(2015)
White 31,178 76.1% 31,065 74.6%
Black or African American 759 1.9% 916 2.2%
American Indian and Alaska
Native
407 1.0% 261 0.6%
Asian 2,144 5.2% 2,658 6.4%
Native Hawaiian and Other
Pacific Islander
179 0.4% 147 0.4%
Other Race 3,967 9.7% 4.022 9.7%
Two or More Races 2,337 5.7% 2,582 6.2%
Hispanic or Latino (of any race) 9,068 22.1% 10,035 24.1%
Source: Bay Area Census 2010, United States Census 2010, American Community Survey, 2015
According to the Sonoma
County’s 2016 Rohnet Park
Local Economic Profile as the
community moves closer to the
year 2020, a new trend
developing is the increase of
the hispanic population within
the City of Rohnert Park.
Between 2010 and 2020 there
is predicted to be a 4
percentage point increase.
Table 2.3: Race and Ethnicity Data Comparison
Figure 2.12: Race and Ethnicity Data Comparison
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Educational Attainment
The information and pie chart below are obtained from the 2016
Rohnert Park Local Economic Profile. In 2015 the population
of those 25 and older, 23% of residents had obtained a High
School Diploma. This is higher than Sonoma County in the
same year with 20% of residents obtaining diplomas. The
category of Some College, consisting of individuals who have
taken college courses but who have never received their degree.
In 2015, about 18% of residents had obtained a Bachelor’s
Degree and around 7% had received a Graduate or Professional
Degree.
Figure 2.13: Educational Attainment
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Economic Trends & Employment
Rohnert Park is located in Sonoma County which is a world destination for tourism. A local Economic Profile of Rohnert Park
completed by the City and Sonoma County in 2016 illustrates how the diverse economy and economic growth in the larger Bay Area
has impacted Rohnert Park.
Rohnert Park’s seasonally unadjusted unemployment rate was 4.5% in June 2015, higher than Sonoma County (4.3%) for the same
month. Compared to June of the previous year, Rohnert Park’s unemployment rate is down 1.2 points from 5.7%. Unemployment
remains significantly lower in Rohnert Park compared to its peak of 11% in March of 2010. Rohnert Park’s unemployment rate is
below the state (6.2%), as well as the nation (5.5%).
Total employment in Rohnert Park was 22,100 in June 2015,
which is up 2.3% from a year earlier. Although it is
following an increasing trend, we are noticing a pattern of
seasonal employment spikes in the numbers, and
employment in Rohnert Park has not regained its maximum
from 2008. The total number of business establishments in
2015 in Rohnert Park is 1,555. Sonoma County has about
25,800 business establishments.
About 52% of Rohnert Park’s employed population is in the
category of Services, which includes education, health care,
tourism and legal services. The second largest sector is
Retail Trade. This is very similar to the county average,
though there is a higher prevalence of Services and Retail
Trade in Rohnert Park, while the county has higher
percentages of agriculture and manufacture. Rohnert Park
also supports Sonoma State University (SSU). The campus is
214 acre that supports 7,000 full time equivalent (FTE)
students and 1,200 employees, making it one of the largest
employers in the area. In the future SSU looks to extend its
capacity to support up to 10,000 FTE students.
Figure 2.14: Rohnert Park Unemployment
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Critical Facilities and Populations
The LHMP Team identified a number of critical facilities for study and incorporation into the hazard vulnerability and risk analysis.
Because of the confidential nature of some facilities (like water pumps), they are not included in the table below. Damage to these
facilities has the potential to impact the quality of life of residents and to impair the response and recovery from disaster events.
In addition to City-owned properties, several other facilities that provide important services to the city were included. These include,
medical facilities, schools, and mobile home parks.
Table 3.1: Facility Address Facility Type
City Properties
City Hall 130 Avram Avenue Government Center
Corporation Yard (Public Works) 600 Enterprise Drive Public Works
Senior Center 6800 Hunter Drive Community
Community Center 5401 Snyder Lane Community
Burton Avenue Recreation Center 7421 Burton Avenue Community
Spreckels Performing Arts Center 5409 Snyder Lane Community
Callinan Recreation Center 5405 Snyder Lane Community
Animal Shelter 301 J Rogers Lane Community
Pump Facility 201 J Rogers Lane Public Works
Public Safety Facility (Main) 500 City Center Drive Government Center
Fire Station 2 (North) 5200 Country Club Drive Fire
Fire Station 3 (West) (Future) 5870 Labath Avenue Fire
Fire Station 4 (South) 1312 Maurice Avenue Fire
State Farm Expressway Landscaping State Farm Expressway Public Works
Enterprise Avenue Landscaping Enterprise Avenue Public Works
Water Tanks Various Locations Public Works
Parks
Alicia Park 300 Arlen Drive Park
Benicia Park 7471 Bernice Avenue Pool
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Table 3.1: Facility Address Facility Type
Benicia Pool 7421 Burton Avenue Park
Caterpillar Park 7430 Circle Drive Park
Colegio Vista 1200 Southwest Boulevard Park
Dorotea Park 895 Santa Dorotea Park Park
Eagle Park 1115 Emily Avenue Park
Gold Ridge Park 1455 Golf Course Drive Park
Golis Park 1450 Golf Course Drive Park
Honeybee Park 1170 Golf Course Drive Park
Honeybee Pool 1170 Golf Course Drive Pool
Ladybug Park 8517 Liman Way Park
Magnolia Park 1401 Middlebrook Park
Magnolia Pool 1501 Middlebrook Way Pool
Oak Grove Park (Future) Keiser Avenue Park
Rainbow Park 1345 Rosana Way Park
Sunrise Park 5201 Snyder Lane Park
Twin Creeks Park Kerry Road Park
Willow Glen Park (Future) Bodway Parkway Park
Robert's Lake 5010 Robert's Lake Road Park
Rohnert Bark (Dog Park) 5010 Robert's Lake Road Park
Field of Friends (Dog Park) 7471 Bernice Avenue Park
Creekside Multi-Use Paths N/A Multi-Use Paths
Municipal Golf Course (North) 100 Golf Course Drive Park
Municipal Golf Course (South) 100 Golf Course Drive Park
Non-City Facilities
California Highway Patrol 6100 Labath Avenue State
SMART Station N/A (Rohnert Park Expressway) Transportation
Sutter Pacific 1400 Medical Center Drive Medical
Kaiser Permanente 5900 State Farm Drive Medical
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Table 3.1: Facility Address Facility Type
Rohnert Park Cancer Center 301 Professional Center Drive Medical
Schools
Marguerite Hahn Elementary 825 Hudis Street School
Evergreen Elementary 1125 Emily Avenue School
Technology Middle School 7165 Burton Avenue School
Rancho Cotate High School 5450 Snyder Lane School
Monte Vista Elementary 1400 Magnolia Avenue School
Lawrence E. Jones Middle School 5154 Snyder Lane School
Richard Crane Elementary 1290 Southwest Boulevard School
John Reed Elementary 390 Arlen Drive School
Waldo Rohnert Elementary 550 Bonnie Avenue School
Technology High School 1801 East Cotati Avenue School
La Fiesta Elementary 8511 Liman Way School
Sonoma State University 1801 East Cotati Avenue University
Credo High School 1300 Valley House Drive School
Mobile Home/RV Parks
Rancho Verde 650 Rohnert Park Expressway Mobile Home Park
Rancho Grande 5099 Snyder Lane Mobile Home Park
Rancho Feliz 6607 Redwood Drive Mobile Home Park
Valley Village 6401 Country Club Drive Mobile Home Park
Las Casitas 7545 Bridget Drive Mobile Home Park
Wine Country RV Park 7450 Cristobal Way RV Park
Table 3.2: Parks, Recreation Facilities, and Open Space Acres Total per 1,000 residents
Neighborhood, Community, and Mini-Parks 116 2.9
Golf Courses 310 7.8
Other Recreational Facilities 47.5 1.1
TOTAL 473.5 10.9
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Table 3.3: Infrastructure
Roads 130 miles
Rail 4 miles
Bridges and Overpasses 20 (total)
Other Infrastructure
The City of Rohnert Park has the typical types of buildings, water and power systems of a community that experienced the majority of
its growth between 1980 and 1999. A brief description follows:
Buildings – Rohnert Park does not have a historic central business district. The majority of the city’s structures are single-family, one-
story homes built from wood built after 1960. Rohnert Park has no unreinforced masonry buildings. A, B, and C Sections of the city
are most at risk because they are the oldest; A Section being built between 1958-1962, B Section from 1963-1965, and C Section from
1977-1980.
Water – The City of Rohnert Park currently derives its drinking-water supply from a well field consisting of 42 municipal supply
wells, 31 of which were active in 1999; and eight active connections to the Sonoma County Water Agency (SCWA) Petaluma
Aqueduct, which supplies water from the Russian River. The Sonoma County Water Agency operates and maintains a water
transmission system authorized by the Agreement for Water Supply and Construction of Russian River-Cotati Intertie Project. Parties
to the Agreement are the Agency and eight public entities, including Rohnert Park. The total amount of water pumped from the 31
operational wells in 1999 was approximately 1.5 billion gallons. Agricultural users in the vicinity of Rohnert Park use a combination
of private well water and reclaimed water for irrigation. Canon Manor residences use both shared and individual wells as their water
supply.
Sewer – All development within the 1999 City limits was connected to sewer service as of 1999. The City also provides sewer service
to the Sonoma State University (SSU) campus, located east of the 1999 City limits. Residential development in Canon Manor, located
outside the 1999 City limits but within its sphere of influence, is served by septic systems, not City sewers. Sewer mains collect
wastewater and transport it to the Rohnert Park Pumping Station. As of 1999, the wastewater mains were adequate in size to serve the
area within the 1999 City limits. A 24-inch interceptor sewer main extends westward from the pumping station to the treatment plant.
Power – The only significant generating plant in the County is the Geysers Project. The largest geothermal plant in the world, the
Geysers produces 25% of Sonoma County’s non-hydro green electricity.
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Evacuation Routes
US Highway 101 is the primary evacuation route from Rohnert Park. The highway is primarily a north-south route. Other evacuation
routes include Petaluma Hill Road on the east side of town, Stony Point Road on the west side of town, Crane Creek Road, leading to
Bennett Valley on the east, and Highway 116 leading west (via Cotati) towards Sebastopol.
Figure 3.1: Map of Rohnert Park Transportation
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Figure 3.2: Critical Facilities
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Figure 3.3: Vulnerable Populations
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Table 3.4: Vulnerable Populations
Child Care and Special Programs Residential Care
Khela, Randa FCHH 1336 Middlebrook Casa Rohnert Park 1033 San Francisco
YMCA (Monte Vista Campus) 1399 Magnolia Villa Alicia 1068 San Francisco
Sacramento Family Child Care 14 Cedar Cir Rollinghills Rest Home 1225 Cloister Ct
4C's Gold Ridge Preschool 1455 Golf Course Dr Bishop's Care Home 1393 Jasmine Cir
Zaki, Sherine FCCH 205 Fig Ct Sarah’s Young Adult Home 1520 Griffin Way
Kraal Family Day Care 375 Bruce Ave Sunlight Villa 339 Bonnie Ave
Little Ones Backyard Club 399 College View Dr Fairway Place 4796 Fairway Dr
Hede Family Child Care Home 4303 Gilford Ln Bishop’s Care Home II 4990 Filament St
Hannah Grace Daycare 47 Alison Ave Stedman's Schloss 5249 Daniel Dr
Early Learning Institute 484 Rohnert Park Expy Gardenia House 5389 Eunice St
Big Brothers & Big Sisters 5685 Redwood Dr 210 Reed’s Guest Home 5590 Country Club Dr
Kindercare 6150 State Farm Dr Liberty Independent Living Services 5685 Redwood Dr 105
Sonoma County 4-H Center 6445 Commerce Blvd Exceptional Care Home of RP 6069 Donna Ct
Sherine Zaki Family Child Care Home 7183 Circle Dr Chez Louise 6084 Country Club Dr
Burton Avenue Rec Center 7421 Burton Ave Chez Louise II 6299 Country Club Dr
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Boys and Girls Club 7450 Santa Barbara Dr Reed’s Guest Home #2 7300 Burton Ave
Hlinka Family Daycare 7599 Bonita Ave Susie's Care Home 7334 Carioca Ct
YMCA Sunshine 825 Hudis St Scils Aaron House 735 Bonnie Ave
Bishop's Care Home 1290 Southwest Blvd Kennemer Home 7527 Boris Ct
Becoming Independent 320 Raley’s Towne Centre Norma’s Daycare 7577 Adrian Dr
Sonoma County Adult and Youth 7345 Burton Ave Sarah’s Group Home 8019 Adrian Dr
Ferrari Daycare 7802 Adrian Dr Teaching Living Concepts 804 Lombard Way
Private Schools Senior Services and Housing
El Colegio School 1059 Camino Coronado Rohnert Park Senior Center 6800 Hunter Dr A
Learning to Learn 1300 Medical Center Dr Oakview Retirement Community 1350-1358 Oak View
La Petite Academy 1301 Medical Center Dr Altamont 300 Enterprise Dr
Cotati Rohnert Park Community Day 1298 Southwest Blvd Doherty Commercial Building 125 Southwest Blvd
Redwood Country Day School 1340 Medical Center Dr
Pathways Charter School 150 Professional Center
Mount Taylor Children’s Center 190 Arlen Dr
Cross and Crown Lutheran School 5475 Snyder Ln
Berean Baptist Christian Academy 6298 Country Club Dr
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HAZARD IDENTIFICATION, ANALYSIS AND ASSESSMENT
Hazards are risks that Rohnert Park wants to identify in order to determine the
potential impacts to people, economy, and the built and natural environments of
the community. Identifying hazards is just one step in the planning process, but
provides the foundation for the rest of the mitigation planning process, which
focus on identifying and prioritizing actions to reduce risk to hazards.
Rohnert Park wants to be prepared in emergency situations by being resilient
which will minimize the risk for loss of community livelihood and assets.
Rohnert Park looks to FEMA’s definition of risk which states: “the potential for
damage, loss, or other impacts created by the interaction of natural hazards with
community assets (5-1).” Natural hazards, risk, and community are inevitably
connected. It is up to the City to be as prepared as possible to make sure risk is
minimalized, overall making it easier for the City to respond. The image below from
FEMA illustrates the concept of risk as the relationship between hazards and community. Risk is overlapping both, but the LHMP will
help identify key information such as Rohnert Park’s own geographic environment, and the hazards associated with that. This
awareness closes the overlap of risk making Rohnert Park more resilient.
Using FEMA’s hazard mitigation planning resources as guidance, the Rohnert Park LHMP team analyzed the relevance of a
comprehensive list of natural hazards in Rohnert Park. The team used the 2012 Emergency Management Plan as a start to identify the
risks and hazards that were most pertinent to the City.
FEMA Element B: Hazard Identification and Risk Assessment
• B1. Does the Plan include a description of the type, location, and extent of all natural hazards that can affect each jurisdiction?
44 CFR 201.6(c)(2)(i) and 44 CFR 201.6(c)(2)(iii)
• B2. Does the Plan include information on previous occurrences of hazard events and on the probability of future hazard events
for each jurisdiction? 44 CFR 201.6(c)(2)(i)
• B3. Is there a description of each identified hazard’s impact on the community as well as an overall summary of the community’s
vulnerability for each jurisdiction? 44 CFR 201.6(c)(2)(ii)
• B4. Does the Plan address NFIP insured structures within each jurisdiction that have been repetitively damaged by floods? 44
CFR 201.6(c)(2)(ii)
Figure 3.4: Risk Assessment
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FEMA has identified 21 unique hazards that it recommends for evaluation and inclusion in a hazard mitigation plan. Several of these
hazards are not applicable to Rohnert Park. Because of past events, communities may also include other hazards not included on
FEMA’s list. The Planning Team evaluated a list of hazards, including those recommended by FEMA and determined which hazards
should and should not be included in the Plan. Table 3.5 shows the hazards that the LHMP Team evaluated.
Table 3.5: Evaluated Hazards for Rohnert Park LHMP
Hazard Decision Explanation
Avalanche Exclude Rohnert Park is not near mountainous areas where avalanches occur.
Climate Change Include (as factor) Climate change is not stand-alone but affects many other hazards.
Coastal Erosion Exclude Rohnert Park is not a coastal community.
Coastal Storm/Storm Surge Exclude Rohnert Park is not a coastal community.
Dam Failure Include Small portions of Rohnert Park lie within a dam failure inundation zone.
Disease and Pests Exclude These are not considered a sufficiently high threat to the City.
Drought Include Rohnert Park has been affected by severe droughts in the past.
Earthquakes/Liquefaction Include Rohnert Park lies in an area affected by earthquakes in the past.
Erosion/Expansive Soils Exclude Neither are a concern for the City of Rohnert Park.
Extreme Cold and Heat Exclude These are not a concern for the City, although heat may be in the future.
Fault Rupture Include Although not in a fault rupture zone, one is in proximity to the City.
Flood Include Flood zones are present in Rohnert Park.
Hailstorms Exclude Hailstorms are not an issue of concern in Rohnert Park.
Hazardous Materials Include Included, although generally not an issue of concern in Rohnert Park.
Human Caused Hazards Exclude There are no human caused hazards that merit inclusion in Rohnert Park.
Hurricane/Lightning/Wind Exclude Rohnert Park is not affected by hurricanes or other severe storms.
Land Subsidence Exclude This is not a hazard of concern in Rohnert Park.
Landslide Include There is only minor risk of landslides in outlying areas of Rohnert Park.
Sea Level Rise Exclude Rohnert Park is not a coastal community.
Severe Winter Storms Exclude Refers to blizzards and ice storms; not a concern for Rohnert Park.
Tornado Exclude Tornados are not a hazard of concern for Rohnert Park.
Tsunami Exclude Rohnert Park is not a coastal community.
Volcano Exclude There are no known volcanoes near Rohnert Park.
Wildfire Include There are areas of elevated fire risk in and adjacent to Rohnert Park.
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Hazard Prioritization
FEMA guidance recommends that the Planning Team prioritize hazards using four individual criteria. The four criteria are as follows:
• Probability: the likelihood of the hazard occurring in the future in the community
• Location: the size of the affected area in the community if the hazard occurs
• Maximum probable extent: the severity of the direct damage to the community from the hazard
• Secondary impacts: the severity of indirect damages to the community from the hazard (e.g., the loss of water service a s a
consequence of damage to infrastructure)
For each criterion, the Planning Team assigned a score of 1 to 4, consistent with FEMA guidance. The Planning Team then assigned a
weighting factor to each criterion, using values recommended by FEMA, with more important criteria receiving a higher weighing
factor. Table 3.6 shows the FEMA recommended rubric used by the Planning Team for this prioritization.
Table 3.6: Hazard Criteria Ranking Scores and Weighing Factors
Probability Maximum Possible Extent
Based on estimated likelihood of
occurrence from historical date
Weighing Factor: 2.0 Based on percentage of damage to
typical facility in community
Weighing Factor: 0.7
Probability Score Impact Score
Unlikely 1 Weak – little to no damage 1
Occasional 2 Moderate – some moderate damage 2
Likely 3 Severe – devastating damage 3
Highly Likely 4 Extreme – catastrophic damage 4
Location Secondary Impacts
Based on size of geographical area of
community affected by hazard
Weighing Factor: 0.8 Based on estimated secondary impacts
to community at large
Weighing Factor: 0.5
Affected Area Score Impact Score
Negligible 1 Negligible – no loss of function 1
Limited 2 Limited – minimal loss of function 2
Significant 3 Moderate – some loss of function 3
Extensive 4 High – major loss of function 4
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Threat Level for Included Hazards
The LHMP Team combined the assigned value of 1 to 4 for each criterion with its weighing factor to determine an overall score for
each criterion. In accordance with FEMA guidance the team then summed the scores for location, maximum probable extent, and
secondary impacts to calculate the total impact score for each hazard. Lastly, the LHMP Team multiplied the impact score by the
probability score to arrive at a total score for each hazard. A total score of 0 to 12 is considered a low-threat hazard, a score of 12.1 to
42 is considered a high-threat hazard. Table 3.7 shows the criterion scores, total scores, and threat levels for all hazards in the Plan.
Table 3.7: Scores and Threat Levels for Included Hazards
Hazard Probability Location Primary Impact Secondary Impact Total Score Threat Level
Dam Failure 1 1 1 1 4.2 Low
Drought 4 4 3 3 54.4 High
Earthquake 4 4 4 4 64.0 High
Fault Rupture 2 1 1 2 6.5 Low
Flood 3 2 3 3 31.2 Medium
Hazardous Materials 1 1 1 1 4.2 Low
Landslide 1 1 1 1 4.2 Low
Liquefaction 1 2 1 1 5.6 Low
Wildfire/WUI-Fire 3 4 3 3 40.8 Medium
Based on this scoring and calculation, drought and earthquake come in with the highest threat level, with flood and wildfire at a
medium threat level. All other hazards analyzed in this Plan are at a low threat level.
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Earthquakes
Hazard Description
Earthquakes happen when two tectonic plates slip past
each other beneath the earth’s surface. At the surface, the
location of this slip is called a fault. As the plates slide
past each other, the stresses between them tend to cause a
buildup of energy that when released causes an
earthquake. The stored energy from this process is
released as seismic waves, causing ground shaking in the
area around the slip. The deformation of plates and
accumulated stress from this process creates faults in a
wider area around the plate boundary, meaning that
earthquakes can happen in areas outside of the plate
boundary itself.
Earthquakes vary in size and intensity with a range of
potential impacts. The amount of damage from an
earthquake is determined not only by the duration and
intensity of ground shaking but also by the conditions in
the impacted area, including soil conditions, construction
quality, distance from the center of the earthquake, and the
type of fault rupture. This hazard profile covers fault
rupture, ground shaking, and liquefaction, the most common impacts from an earthquake. When a fault ruptures this is the actual
movement and displacement of the ground’s surface along the fault boundary which is considered the earthquake. Depending on the
type of fault, this displacement may be horizontal, vertical, or both. Damage from fault rupture can be severe depending on the size of
the displacement, but is limited to the relatively small area along the fault boundary where the slip occurred. Not all earthquakes result
in fault rupture that is visible at the surface, and strong earthquakes can occur without any discernible displacement along the
boundary.
Hazard Location and extent
The City of Rohnert Park is just one out of 97 cities within the Bay Area that are within 10 miles of an active fault. Rohnert Park is in
the vicinity of several known active and potentially active earthquake faults including the San Andreas and Healdsburg/Rodgers Creek
Figure 3.5: Earthquake Intensity Scale
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and the Hayward fault. The City of Santa Rosa is 8 miles to the north of Rohnert Park and has the Rodgers Creek fault running north-
south through the center of the City of Santa Rosa. This does pose a high risk of seismic activity in the greater Santa Rosa area.
A major earthquake occurring in or near this jurisdiction may cause many deaths and casualties, extensive property damage, fires,
hazardous material spills and other ensuing hazards. The Rodgers Creek fault is considered the greatest earthquake threat to Sonoma
County because of the high probability of rupture and its proximity to the County’s greatest concentration of population, governmental
services and infrastructure. The effects could be aggravated by aftershocks and by the secondary effects of fire, hazardous
material/chemical accidents and possible failure of waterways and dams. The time of day and season of the year would have a
profound effect on the number of dead and injured. Such an earthquake would be catastrophic in its effect upon the population and
could exceed the response capabilities of the City of Rohnert Park, the Sonoma County Op Area and the Governor’s Office of
Emergency Services and other state agencies. Damage control and disaster relief support would be required from other local
governmental and private organizations, and from the state and federal governments.
Hazard Vulnerability and Risk Assessment
Ground shaking: The most significant earthquake action in terms of potential structural damage and loss of life is ground shaking.
Ground shaking is the movement of the earth's surface in response to a seismic event. Ground shaking impacts can lead to surface
rupture, liquefaction, landslides, and infrastructure failures, which could lead to fires and other secondary hazards. The geology of the
impacted area alters the amount of ground shaking felt. Thick, water-saturated, unconsolidated materials will generally experience
greater shaking motion than areas of firm bedrock.
The size and magnitude of an earthquake have different ways of being measured. The magnitude of the earthquake, distance from the
epicenter, and characteristics of surface geology determine the intensity of the ground shaking and the resultant damages. The
magnitude is a number that characterizes the relative size of an earthquake. Magnitude is based on measurement of the maximum
motion recorded by a seismograph. Many scales, such as the Richter scale, do not provide accurate estimates for the magnitudes of
large earthquakes. To account for these large earthquakes, the moment magnitude scale (abbreviated as MMS; denoted as MW or M)
is preferred for its ability to cover a wide range of earthquake sizes and be applied globally. The moment magnitude scale is based on
the total moment release of the earthquake. Moment magnitude is a product of the distance a fault moved and the force required to
move it. It is derived from modeling recordings of the earthquake at multiple stations. The Modified Mercalli Intensity Scale for
Earthquakes shown in the Table below measures ground shaking intensity in terms of perception and damage and takes into account
localized earthquake effects. The amount of shaking experienced at different locations varies based not only on the overall magnitude
but also on the distance from the fault that ruptured in the earthquake, geologic conditions, and the level of preparedness built into
surrounding infrastructure. This hazard is the primary cause of the collapse of buildings and other structures
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Liquefaction: Many areas may have buildings destroyed or unusable due to the phenomenon of liquefaction. Liquefaction is the loss
of shear strength of a soil. The shear strength loss results from the increase of water pressure caused by the rearrangement of soil
particles induced by shaking or vibration. Liquefaction has been observed in many earthquakes, usually in soft, poorly graded granular
materials (i.e., loose sands), with high water tables. Liquefaction usually occurs in the soil during or shortly after a large earthquake.
In effect, the liquefaction soil strata behave as a heavy fluid. Buried tanks may float to the surface and objects above the liquefaction
strata may sink. Pipelines passing through liquefaction materials typically sustain a relatively large number of breaks in an earthquake
(Rohnert Park Emergency Management Plan).
Hazard History
The Bay Area has experienced significant, well-documented earthquakes.
Since 1855, more than 140 earthquakes have been felt in the Santa Rosa area.
Although earthquake records prior to the year 1900 are difficult to interpret,
seven earthquakes are believed to have caused damage to structures in Sonoma
County during the 19th century. Two earthquakes are of note: the 1868 M7.2
earthquake on the Hayward Fault, and the 1898 M6.7 earthquake believed to
have occurred on the Rodgers Creek Fault. Although damage from these two
events was limited due to the area’s sparse population at the time, a recurrence
of either of these events could result in significant damage to today’s
widespread and varied infrastructure and building stock. The April 18, 1906,
M8.3 earthquake on the northern segment of the San Andreas Fault, known for
devastating San Francisco, caused major damage in Santa Rosa, Sebastopol,
Healdsburg, Petaluma and other communities. Santa Rosa, only 20 miles from
the San Andreas Fault, is said to have suffered more damage proportionally to
its size than any other Bay Area city.
The 1969 Rodgers Creek / Healdsburg Fault Earthquake was the last major earthquake to occur in the Sonoma County area on
October 1, 1969. Two earthquakes of Magnitudes 5.6 and 5.7 originated near the juncture of the Rodgers Creek and Healdsburg Fault,
approximately two miles north of Santa Rosa. Total building damage was estimated at $6 million, with dwelling contents losses at
$1.25 million. Several County buildings suffered damage, including the Library, Post Office, and Veterans Memorial Building. There
was more than expected damage to the newly constructed two-story Sonoma County Social Services Building at the County
Administration Center. The 1989 Loma Prieta Earthquake, 6.9 magnitude earthquake was caused by a slip along the San Andreas
Figure 3.6: 2014 Napa Earthquake
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Fault. Though the damage in Sonoma County from the quake was very minor, the quake killed 63 people and injured 3,757 throughout
Northern California. It caused a total of over 16,700 housing units to be uninhabitable throughout the Monterey and San Francisco
Bay Areas and left some 3,000-12,000 people homeless. The most recent earthquake in this area, the 2014 Napa Quake, was felt
throughout Sonoma County and in Rohnert Park and cause millions of dollars of damage in neighboring Napa County.
Risk of Future Occurrences
A major earthquake occurring in or near this jurisdiction may cause many deaths and casualties, extensive property damage, fires,
hazardous material spills and other ensuing hazards. The Rodgers Creek fault is considered the greatest earthquake threat to Sonoma
County because of the high probability of rupture and its proximity to the County’s greatest concentration of population, governmental
services and infrastructure. The effects could be aggravated by aftershocks and by the secondary effects of fire, hazardous
material/chemical accidents and possible failure of waterways and dams. The time of day and season of the year would have a
profound effect on the number of dead and injured. Such an earthquake would be catastrophic in its effect upon the population and
could exceed the response capabilities of the City of Rohnert Park, the Sonoma County Op Area and the Governor’s Office of
Emergency Services and other state agencies. Damage control and disaster relief support would be required from other local
governmental and private organizations, and from the state and federal governments.
Extensive search and rescue operations may be required to assist trapped or injured persons. Injured or displaced persons could require
emergency medical care, food and temporary shelter. Identification and burial of many dead persons would pose difficult problems;
public health would be a major concern. Mass evacuation may be essential to save lives, particularly in areas downwind from
hazardous material releases. Many families would be separated particularly if the earthquake should occur during working hours, and
a personal inquiry or locator system could be essential to maintain morale. Emergency operations could be seriously hampered by the
loss of communications and damage to transportation routes within, and to and from, the disaster area and by the disruption of public
utilities and services.
The economic impact on the City of Rohnert Park from a major earthquake would be considerable in terms of loss of employment and
loss of tax base. Also, a major earthquake could cause serious damage and/or outage of computer facilities. The loss of such facilities
could curtail or seriously disrupt the operations of banks, insurance companies and other elements of the financial community. In turn,
this could affect the ability of local government, business and the population to make payments and purchases.
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Figure 3.7: Probability of Earthquake Intensity (Shaking)
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Figure 3.8: Potential Liquefaction
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According to the USGS, there is a 31% chance of a major earthquake along the Rogers Creek fault by 2038 and a 93% probability of a
magnitude 6.7 or greater in Northern California by 2038.
Climate Change Considerations
Seismic events are not directly impacted by climate change. It is uncertain the likelihood, size and severity of seismic events. Since the
field of climate change science is dynamic, the City will continue to review and summarize new research that occurs on this topic
during the next update cycle.
Flooding
Hazard Description
Flooding is a temporary condition in which land that is normally dry is partially or completely inundated. Flooding occurs when water
bodies, such as streams, rivers, lakes, or reservoirs, are abnormally high and overflow into adjacent low-lying areas. These areas are
known as floodplains, defined by their exposure to risk of recurring floods. Given Rohnert Park’s inland location the City is protected
from coastal flooding which is associated with high tides and coinciding strong winds. Flooding within the City’s planning area are a
result of heavy rains in low-lying areas with limited drainage routs and along creeks that are prone to flooding in 100-year storm
events. Floods can be powerful enough to move large objects swiftly into other objects, cause damage to buildings and infrastructure,
and weaken foundations and soils. Secondary impacts of flooding, including saturated soils and erosion from flooding events can
cause trees to weaken and collapse, increasing the potential for property damage and loss of life. Taken from the City’s Emergency
Management Plan it is stated that floods are generally classed as either slow-rise or flash floods. Slow-rise floods may be preceded by
a warning time lasting from hours to days or possibly weeks. Evacuation and sandbagging for a slow-rise flood may lessen flood-
related damage. Conversely, flash floods are the most difficult to prepare for, due to the extremely short warning time, if any is given
at all. Flash flood warnings usually require immediate evacuation within the hour. Within Sonoma County floods are the most
frequent natural hazard, and causing the greatest amount of property losses. Within the state, floods are second most common types of
disaster, fires being the first.
Before Rohnert Park was developed, most rainfall fell onto natural areas. The water soaked into the ground until it reached a
saturation point, at which time it traveled, sometimes below the surface of the soil, sometimes in above-ground swales, via sheet flow,
to the nearest creek or water body. With urban development of the area, impervious surfaces were created. An impervious surface can
be a constructed surface -- like paved roads, parking lots and rooftops -- or a natural surface compacted in some way so that the
infiltration of surface water is impacted or prevented. Rain falling on impervious surfaces creates runoff that is sent through our storm
water system of street gutters and storm drains, quickly to the nearest creek and downstream.
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While our conventional storm water system of gutters, pipes and channels has done its job to protect properties and lives here in this
urbanized area, it also has had replaced some of the beneficial functions of natural surfaces that protect environments and populated
areas downstream, such as lessening the peak storm water level, slowing the velocity of water through the waterbodies, providing
infiltration to groundwater, and filtering out pollutants. The City’s Public Works Department maintains the City-owned portions of the
storm water system, including gutters, inlets, catch basins, pipes and outfalls.
The Sonoma County Water Agency (SCWA) manages most of the flood control channels that course through Rohnert Park. The
channels in Rohnert Park are included in "Zone 1A" (Laguna de Santa Rosa - Mark West Creek watershed), one of nine geographical
zones encompassing a major watershed. These flood control zones were established in 1958 as a means of financing the construction
and maintenance of flood protection works within Sonoma County. SCWA either owns in fee the rights-of-way for constructed flood
control channels, or holds easements on them for maintenance. Maintenance of flood control channels and creek beds are under
contractual agreement with Sonoma County Water Agency.
Hazard Location and extent
Areas in Rohnert Park are flood prone in heavy rains. This can be visualized on the Rohnert Park 2015 Flood Areas Map. There are
several major creeks that intersect with Rohnert Park and could potentially cause flooding within the 100-500 year flood plain and
general low-lying areas. The creeks identified on the map are Wilfred Bellvue Channel, Coleman Creek, Five Creek, Crane Creek,
Hinebaugh Creek, Copeland Creek, and Laguna De Santa Rosa. A large area in the Northwest corner of the City right outside city
limits is prone to flooding, that looks to span 1 square mile in area where the Laguna de Santa Rosa, Hinebaugh Creek and Wilfred
Bellvue channel intersect. Area 1 on the map is adjacent to this area inside the city limits and is designated as Rancho Verde Mobile
Home Park and is lining with Hinebaugh Creek. The streets across the Hinebaugh Creek near Labath Ave are prone to flooding as
well. Areas lining the major creeks such as Copeland Creek on Avram Avenue when City Hall is located is prone to flooding. In the
Northeast corner of the City where the Rohnert Park Municipal Golf Course is located including some streets of the neighboring
residential are prone to flooding during the rainy seasons as Coleman Creek may overflow. Other areas designated on the map have
sporadic locations of low-lying flood prone areas during the rainy season.
Hazard History
Flooding has had a serious impact on the county as a whole in the past. The most recent occurrence was in the winter of 2005-2006
when rainfall measured in the City of Santa Rosa at 17.6 inches (NOAA 2013). The President declared this flood a major disaster, and
more than 100 roadways were blocked due to flooding or landslides. Some 2,100 business and residential properties were inundated
and 50,000 residents were without power (NOAA 2013). Sonoma County business and residential damages were estimated at $104
million (NOAA 2013). The City was impacted by the 2005/2006 Winter Storms. General impacts from the winter storms were
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flooding and power outages. Public works crews assessed the flooded areas and were able to clean out blocked drainage trash gates,
removed debris from ditches and culverts and placed flooded, road closed ahead, and road closed signs, as needed, on flooded road
sections to warn the public of flooded areas. Public works has some provisions for sandbags – primarily available only to areas where
living space would be flooded or impacted. In areas where trees fell in the roadway, the trees were moved out of the roadway and
when the storm cleared the trees were cut up and removed. Vehicles, properties and buildings sustained damage from flood waters
particularly on Martin Avenue and Heartwood Court.
Hazard Vulnerability and Risk Assessment
The most readily available source of information regarding the 100-year flood is the Flood Insurance Rate Maps (FIRMs) prepared by
FEMA to support the National Flood Insurance Program (NFIP). The standard for floodplain management in the United States is to
delineate and address flood risks within the area inundated by the 100-year flood or base flood. Floods may be quantified in terms of
flow (cubic feet per second (CFS)), water elevation, inundated area, and reoccurrence interval. For instance, a 100-year flood has a 1‐
percent chance of occurring in any given year. Although the recurrence level is based on statistical averages, the actual occurrence of
events varies and could occur at shorter intervals or even within the same year.
Mobile Home Susceptibility
Statewide, the 1996 floods destroyed 156 housing units. Of those units, 61 % were mobile homes and trailers. Many older
manufactured home parks are located in floodplain areas. Mobile homes have a lower level of structural stability than stick-built
homes, and must be anchored to provide additional structural stability during flood events. Because of confusion in the late 1980s
resulting from multiple changes in NFIP regulations, there are some communities that do not actively enforce anchoring requirements.
Lack of enforcement of manufactured home construction standards in floodplains can contribute to severe damages from flood events.
The City of Rohnert Park has participated in the National Flood Insurance Program since 1981. The City does not participate in the
Community Rating System. Staff anticipates seeking City Council direction for participation in the Community Rating System. The
City started participation in the NFIP on June 1, 1981. An update, effective December 2, 2008, was released which reflected the
current requirements of the NFIP for non-coastal communities. In addition to using FEMA maps to regulate flood hazard areas, the
City may require elevation certificates at the building permit stage to verify compliance with NFIP requirements. There are no repeat
loss properties within the City of Rohnert Park.
Identification of Flood Areas
Flood maps and Flood Insurance Studies (FIS) are often used to identify flood-prone areas. The NFIP was established in 1968 as a
means of providing low-cost flood insurance to the nation’s flood-prone communities. The NFIP also reduces flood losses through
regulations that focus on building codes and sound floodplain management. NFIP regulations (44 CFR Chapter 1, Section 60, 3)
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require that all new construction in floodplains must be elevated at or above base flood level. Flood Insurance Rate Maps (FIRM) and
Flood Insurance Studies (FIS) Floodplain maps are the basis for implementing floodplain regulations and for delineating flood
insurance purchase requirements.
A Flood Insurance Rate Map (FIRM) is the official map produced by FEMA which delineates SFHA in communities where NFIP
regulations apply. FIRMs are also used by insurance agents and mortgage lenders to determine if flood insurance is required and what
insurance rates should apply. Water surface elevations are combined with topographic data to develop FIRMs. FIRMs illustrate areas
that would be inundated during a 100-year flood, floodway areas, and elevations marking the 100-year-flood level. In some cases, they
also include base flood elevations (BFEs) and areas located within the 500-year floodplain. Flood Insurance Studies and FIRMs
produced for the NFIP provide assessments of the probability of flooding at a given location. FEMA conducted many Flood Insurance
Studies in the late 1970s and early 1980s. These studies and maps represent flood risk at the point in time when FEMA completed the
studies. However, it is important to note that not all 100-year or 500-year floodplains have been mapped by FEMA.
FEMA flood maps are not entirely accurate. These studies and maps represent flood risk at the point in time when FEMA completed
the studies, and does not incorporate planning for floodplain changes in the future due to new development. Although FEMA is
considering changing that policy, it is optional for local communities. Man-made and natural changes to the environment have
changed the dynamics of storm water run-off since then.
Although many communities rely exclusively on FIRMs to characterize the risk of flooding in their area, there are some flood-prone
areas that are not mapped but remain susceptible to flooding. These areas include locations next to small creeks, local drainage areas,
and areas susceptible to manmade flooding. Communities find it particularly useful to overlay flood hazard areas on tax assessment
parcel maps. This allows a community to evaluate the flood hazard risk for a specific parcel during review of a development request.
Coordination between FEMA and local planning jurisdictions is the key to making a strong connection with GIS technology for the
purpose of flood hazard mapping.
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Figure 3.9: Known Flooding from 2005 Flood Event with Mobile Home Parks
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Figure 3.10: Known Flooding from 2005 Flood Event with Critical Facilities
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Figure 3.11: FEMA Flood Hazard Areas with Mobile Home Parks
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Impact of Development
When structures or fill are placed in the floodway or floodplain water is displaced. Development raises the river levels by forcing the
river to compensate for the flow space obstructed by the inserted structures and/or fill. When structures or materials are added to the
floodway or floodplain and no fill is removed to compensate, serious problems can arise. Flood waters may be forced away from
historic floodplain areas. As a result, other existing floodplain areas may experience flood waters that rise above historic levels. Local
governments must require engineer certification to ensure that proposed developments will not adversely affect the flood carrying
capacity of the Special Flood Hazard Area (SFHA).
Displacement of only a few inches of water can mean the difference between no structural damage occurring in a given flood event,
and the inundation of many homes, businesses, and other facilities. Careful attention should be given to development that occurs
within the floodway to ensure that structures are prepared to withstand base flood events. In highly urbanized areas, increased paving
can lead to an increase in volume and velocity of runoff after a rainfall event, exacerbating the potential flood hazards. Care should be
taken in the development and implementation of storm water management systems to ensure that these runoff waters are dealt with
effectively.
Climate Change Considerations
Scientific evidence involving climate change include more variation in weather patterns for Sonoma County. Overall there are
significant challenges for planning around water supply and flood control. Sonoma County’s wintertime precipitation comes mainly in
storms from the Pacific Ocean brought on atmospheric rivers. Between 1948 and 2011, 87% of floods on the Russian River were due
to atmospheric rivers (Dettinger et al., 2011). With the wettest scenarios being considered, Sonoma County including Rohnert Park
could see almost a 25% increase in precipitation compared to historical (20th century) conditions while the driest scenario projects an
approximately 20% decrease (Climate Ready Sonoma County). By the year 2100 Sonoma County will see bigger, more variable
floods that will cause potentiality in 1) physical danger and economic impact for people living in low-lying areas along rivers and bay
lands, especially those without reliable transportation, 2) Death from drowning and injuries from flood, 3) Public health risks from
damage to sanitation, utility, and irrigation systems, 4) Limitations on access to critical services and 5) Economic impact to businesses
in or affected by flooded areas.
With the calculated changes in precipitation due to climate change there will still continue to be some years with precipitation similar
to historic averages as the error bars for all scenarios in Figure 3.16 overlap with the 0% change axis. However, the warm/wet scenario
forecasts some years with an almost 75% increase in mean annual precipitation while the dry scenarios project years with decreases
between 25-50% of historical averages (Climate Ready Sonoma County).
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Drought
Hazard Description
Droughts are an effect of prolonged periods
of little to no rainfall which result in
shortages of water. Droughts develop over
an extensive period of time. A year with
abnormally little precipitation would be
considered a dry year. Multiple dry years
may develop drought conditions, whereas
multiple years of suitable rain or wet years
will generally alleviate the drought. In years
of drought the inhabitants do slowly feel the
effects. In urban areas, drought conditions
can cause a decrease in available water
supplies, which may lead to increases in
water rates or restrictions in water use.
Communities may need to seek alternative
water supplies to meet demand, which can
be a costly and lengthy process.
Drought conditions change the landscape,
causing vegetation such as street trees,
landscaped areas in public parks to become
water stressed which can lead to plant
disease or death. Drought conditions harden
the ground, which can lead to increased
flooding when rains return because the soil
cannot easily absorb water. Prolonged
drought can also create increased levels of
wildfire risk, with prolonged conflagrations fueled by excessively dry vegetation. Drought is not localized, but occurs simultaneously
across the region, and may extend statewide or across a larger expanse. For the state droughts have been occurring in prolonged stages
that impact every county, as well as local municipalities that are unique in their conditions such as based on local and regional water
Figure 3.12: California Drought as of November 2015
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supply systems, soil conditions, and the typical climate and vegetation land covering. The effects of drought are managed in the Bay
Area through the importation of water and the storage of water in reservoirs.
Hazard History, Location and extent
Droughts are known to reoccur
in California. The State have
developed advance strategies
and water infrastructure
networks to deal with water
shortages. A drought in one part
of the state may have little to no
effect in another part of the
state due to water resources that
are localized. From December
of 2011 to April 2017
California experienced yet
another state-wide drought. In
January 2014, the Governor
declared a State of Emergency
in California in response to
current drought conditions. To
date, 2015 is the driest recorded
year on record in California,
with statewide reservoirs at 18–
67% of average (California
Governor’s Office of
Emergency Services (2015), as
cited in ABAG 2015). Governor
Jerry Brown ordered a statewide
25%t cut in urban water use. A
year ago, 21%of California was considered in drought monitor classification D4, 42%in D3-D4 and 100% of California in D0-D4. As
of April 2017 the Governor declared the drought emergency over. Now that California is flourishing it will not be the last or the
Figure 3.13: California Drought as of August 2017
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longest in the years to come. A drought from 1928 to 1937 affected all parts of the state and was the longest drought in California’s
recorded history. Between 1976 and 1977, California experienced one of its most severe droughts, and 1977 was the state’s driest year
on record.
Major Droughts that affected the Bay Area, according to ABAG were in 1973, 1976–77, 1987–91, and 2007–09. Drought conditions
in 1973 led to a State-declared disaster in Glenn, San Benito, and Santa Clara counties, resulting in $8 million in agricultural loss.
During the statewide drought of 1976 to 1977, four Bay Area counties (Contra Costa, Napa, San Mateo, and Marin) were among those
where a state disaster was declared. Marin, Solano, and Sonoma counties were affected in the 1987–91 drought, which caused $1.7
billion in crop losses nationwide (Cal OES 2013, as cited by ABAG 2015).
Locally, Sonoma County declared an emergency for drought in
February of 2014. A proclamation was adopted calling for water
conservation actions and voluntary water reductions. Rohnert Park
adopted Stage 1-voluntary reductions in February 2014. And
subsequently adopted Stage 1-mandatory 20% reductions in August
2014 to comply with the State regulations mandating a statewide 25%
reduction target. At the drought’s peak in 2015, approximately 9
percent of Sonoma County was classified as level D3 drought
conditions (extreme drought), with the remainder of the county
classified as level D2 (severe drought) which included Rohnert Park.
Figure 3.14: Drought affecting Lake Sonoma in 2014
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Recycled Water System
Rohnert Park’s Recycled Water System provides tertiary treated
recycled water to 31 customers including City parks, two
municipal golf courses, Sonoma State University and several
private commercial properties (see Figure 3.15). The City has
been at the forefront of recycled water use having used recycled
water for over 28 years. In 2015, the City used 310 million
gallons on over 580 acres. The use of recycled water
significantly lessens the potential impacts of droughts on
connected properties. Current development and new city
infrastructure is required to connect to the recycled water
system where feasible.
Drought Vulnerability and Risk Assessment
Given the historical context and extent to which droughts have
happened so far at each spatial level from the state, county, and
local municipality, droughts are unique among hazards in this
LHMP in that droughts are a more regional disaster meaning
that the direct impact is the same throughout the City. Unlike
earthquakes, floods, or wildfires where the risk and severity of
impacts vary within the community. As a result, all of Rohnert
Park is in the potential hazard zone for droughts, and no single
area faces higher direct risks. While the severity of any drought
conditions will be consistent across Rohnert Park, the indirect
impacts of a drought can vary depending on residents’
socioeconomic factors. Droughts often lead to more stringent
water use regulations, which can include increased service rates
for households that use higher amounts of water.
Figure 3.15: Rohnert Park recycled Water System
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Climate Change Considerations
Scientific evidence suggests that Sonoma County, and California
overall are expected to experience more very hot days than in the
past, and overall higher temperatures over a longer period of dry
weather. Spring will come earlier and fall will come later, and
these extended periods of hotter, drier weather will impact
regional water supply. The heat will also increase soil moisture
deficit and reduce groundwater recharge. Reduction in the overall
regional water supply due to reduced precipitation would only
exacerbate the local effects of drought (Climate Ready Sonoma
County).
Figure 3.16: Climate Change Precipitation Projections
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Wildfire/Wildland-Urban Interface Fires
Hazard Description
The combination of highly flammable fuel, long dry
summers and steep slopes creates a significant natural
hazard of large wildland fires in many areas of Sonoma
County. A wildland fire is a fire in which the primary fuel is
natural vegetation. Wildland fires can consume thousands
of acres of vegetation, timber and agricultural lands. Fires
ignited in wildland areas can quickly spread, if unabated, to
areas where residential or commercial structures are
intermingled with wild land vegetation. Similarly, fires that
start in urbanized areas can grow into wildland fires. Wild-
land-urban interface fire hazards are especially pronounced
in areas of high structure densities adjacent to undeveloped
open space areas with dense vegetation. Wildland-urban
interface fire results in death, injury, economic loss and a
large public investment in firefighting activities.
Wildfire behavior is based on three primary factors:
weather, topography and fuel. Wildland fire season in
Sonoma County spans the months after the last spring rains
have fallen and until the first fall or winter rains occur. The
months of August, September and October have the greatest
potential for wildland fires as vegetation dries out, humidity
levels fall, and off shore winds blow. In Northern California,
Diablo Winds, while rare can occur. These are similar to the Santa Ana winds founds in Southern California which can drive fires
swiftly and unpredictably.
The population of tan oak vegetation in various areas of the County has particular risk due to the rise of Sudden Oak Death Syndrome.
In specific areas, tan oak proliferation and the rapid encroachment of the disease has created an environment of increased vulnerability
to wildland fire.
Figure 3.17: ABAG WUI Fire Predicted Risk (orange)
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Hazard Location and extent
Wildfires can be caused by natural events, such as lightning or
high winds. However, most wildland fires are human caused.
Campfires, careless smokers, electrical sparks, and arson cause
most wildland and wildland-urban interface fires. In the City of
Rohnert Park and the adjacent rural areas of Sonoma County,
electrical equipment, such as power lines and transformers, has
caused numerous fires. An emerging cause for concern is fires
started by mowing, use of power equipment and other work
around very dry vegetation. Trees growing into power lines
have caused large and damaging fires within the county.
The adjacent hillsides surrounding Rohnert Park are a high-risk
area for wildfires. With off shore winds any such fire, once
started, could blow fire brands and ash into the City of Rohnert
Park.
Hazard Vulnerability and Risk Assessment
The risk of wildland fires in Rohnert Park is generally low
compared to peer cities in Sonoma County. The City has very
little area that would be considered Wildland-Urban Interface. The City’s planned development patterns, relatively compact nature,
and the existence of an urban growth boundary have prevented Rohnert Park from sprawling out in low densities into the surrounding
hillsides where the risk of fire is greater. The existence of agriculture on three sides of the City, as well as the presence of the City of
Cotati to the south, also mitigate the chances of an extreme fire event. Current mitigation activities include abatement of grassland
areas adjacent to and within the City Limits.
Climate Change Considerations
Changing weather and precipitation patterns as a result of climate change, further impacted by continuing development, will change
the way large fires originate, grow, and ultimately impact Rohnert Park in the future. Increased precipitation during the rainy season
will increase the growth of grass and brush that will later dry out in the summer, increasing the amount of fuel available for fires.
Warmer summers will contribute to drier conditions and will place more stress on plants, bushes and trees leaving them vulnerable to
pests and disease. Increasing numbers of trees may die out, subsequently leaving increased amounts of fuel ready to burn.
Figure 3.18: Typical hillside adjacent to Rohnert Park
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Figure 3.19: Historic (Pre-2017) Wildfires near Rohnert Park
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October 2017 Fire Event
During the night of October 8-9, multiple offshore wind
driven fires ignited across the Counties of Napa and
Sonoma. While no official cause has been determined at the
time of this writing, sparks from electrical lines in strong
winds are considered the likely cause. Sonoma County
experienced the wettest winter on record in 2016-2017
(driving vegetation growth), and one of the hottest summer
on record in 2017 (drying out the same vegetation). These
factors combined to create conditions favorable for rapid
fire growth. The City of Santa Rosa to the north experienced
significant devastation and loss of life in the Tubbs Fire due
to the sudden and overwhelming nature of the event.
An offshoot of the Nuns/Adobe fires, centered in and around
Sonoma Valley, headed east over the hills, generally staying
south of Crane Canyon Road during the early hours of
Monday October 9 (See Figure 3.21). The City of Rohnert
Park mobilized over the coming days to build emergency
fire breaks around the eastern and northern sides of the City.
The G, H, and K Sections were evacuated for a period of
time. Actions by the City, combined with shifting wind
patterns prevented the fire from directly damaging the City
of Rohnert Park.
*After more thorough analysis of the fire event conducted by Sonoma County, Cal OES, FEMA, and the City of Rohnert
Park, additional modifications and additions to this LHMP as pertaining to wildfire hazard mitigation will be included.
Figure 3.20: October 2017 Sonoma County Fires
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Figure 3.21: October 2017 Sonoma County Fires in the Rohnert Park Vicinity
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Minor or Secondary Hazards
While not identified as primary hazards through the planning process, these hazards are still important and have the potential to
directly or indirectly threaten lives, property, and infrastructure in and around Rohnert Park.
Hazardous Materials
Hazard Description
California law defines a hazardous material as follows:
A substance that, because of physical or chemical properties, quantity, concentration, or other characteristics, may either (1)
cause an increase in mortality or an increase in serious, irreversible, or incapacitating illness; or (2) pose a substantial present or
potential hazard to human health or environment when improperly treated, stored, transported, or disposed of, or otherwise
managed (California Health and Safety Code Section 25141b).
Hazardous materials are dangerous substances that encompass a wide range of substances that include toxic substances, flammable or
explosive materials, corrosive substances such as acids, and radioactive substances. While some hazardous materials are dangerous at
all times, others may only be dangerous under specific conditions such as flammable materials, which can be harmless until exposed
to a spark or a heat source. Hazardous materials that are no longer used and have been disposed of or awaiting disposal.
Emergencies involving hazardous materials are often technological and man-made hazards. These types of emergencies also
sometimes occur as a secondary impact of another emergency such as an earthquake or flood.
Hazard Location and Extent
Hazardous material releases can occur from buildings such as factories and processing facilities, as well as from vehicles that transport
chemicals or other hazardous substances. Road vehicles, trains, and (more rarely) aircraft can all suffer accidents that cause a release
of hazardous materials. According to the Rohnert Park Emergency Preparedness Plan 2010, the likelihood of occurrence is every so
often, and the severity of an instance could range of low to high.
Hazard History
According to county records indicated by the Rohnert Park Emergency Management Plan, spill history indicates most problems
occurring in the transportation corridors. Although most of these incidents have been easily handled, the potential still exists for an
extreme threat to life, the environment, and property.
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Hazard Vulnerability and Risk Assessment
In the City of Rohnert Park, commercial businesses that use hazardous materials include, but are not limited to, dry cleaners, film
processors, auto service providers, drycleaners and medical clinics. Residences also generate household hazardous wastes in the form
of paints, thinners, pesticides, fertilizers. Earthquake shaking can release hazardous materials. There is the potential that trucks or train
cars carrying dangerous materials could be tipped over by an earthquake and materials dangerous to health or the environment could
be released. Some of these sources may contain gases or liquids that are potentially harmful to human health. Leaking products present
a serious fire hazard (Rohnert Park Emergency Preparedness Plan 2010).
Hazardous materials also pass through the City in route to other designations via the freeway, rail, and surface street system. The
Department of Transportation (DOT) regulates the transport of hazardous materials on state highways and rail lines using established
criteria for safe handling procedures. Federal safety standards are also included in the California Administrative Code and the
California Health Services Department regulates the haulers of hazardous waste (Rohnert Park Emergency Management Plan 2012).
Risk of Future Hazards
An accident with hazardous materials can happen every once in a while, and especially during a natural disaster like an earthquake or
severe flooding. Hazardous waste generators and users in the City are required to comply with regulations enforced by several federal,
state, and county agencies. The regulations aim toward reducing risk associated with human exposure to hazardous materials and
minimizing adverse environmental effects. Sonoma Fire Department in partnership with the Rohnert Park Department of Public Safety
for fire protection services conduct inspections related to hazardous materials. The Hazardous Materials Compliance Division of the
County Environmental Health Services Department ensures compliance and reporting in accordance with the Sonoma County
Hazardous Waste Management Plan. Highways 101 has a greater potential for a Hazardous Materials release, Petaluma Hill Road and the
Rohnert Park Expressway also has materials traveling through on a daily basis. (Rohnert Park Emergency Management Plan 2012).
Landslides
Hazard Description
Landslides occur when soils on a hill side become unstable and slide down towards the base of the hill. They can occur very quickly
or may transgress slowly over a period of days, weeks, months, or years. Landslides are capable of damaging or destroying any
structures built on or in the moving soil, and the flow of material can cause further damage to any structure in its path. Landslide risk
depends on the types of earth materials of the hillside and the steepness of the slope.
There are multiple types of landslides and they can be triggered by a number of different events, but the two most common forms are
earthquake-induced landslides and moisture-induced (rain, flooding, irrigation) landslides. During Earthquakes a landslide can happen
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because the ground shaking causes the soil unstable and loose. During the rainy season, moister-induced landslides can occur when
the ground soaks up excess water causing the ground to weaken and become unstable. Water is capable of eroding the base of slops on
hillsides causing risk of landslides.
Hazard Location and extent
According to the Rohnert Park Emergency Management Plan, the likelihood of occurrence in very infrequent, and the severity of the
occurrence is low. Landslides can occur in the event of a major Earthquake at a magnitude of 7 to 7.9. However, areas designated at
risk of landslides are entirely outside and away from the city limits.
The rolling hills, coastal ranges, and steep canyons that characterize Sonoma County’s landscape contribute to a widespread landslide
hazard. Landslides are described as downward movement of a slope and materials under the force of gravity. In addition to gravity,
extended periods of intense rainfall during the winter months is the primary cause of landslides in the County. Landslides can also be
triggered by seismic activity. Landslides are a significant secondary hazard to wild land fire, where periods of heavy rainfall on
denuded slopes cause landslides and mudslides.
The main types of landslide activity that can impact Sonoma County include:
• Slides: Mass movements, where there is a distinct zone of weakness that separates the slide material from more stable
underlying material.
• Falls: Abrupt movements of masses of geologic materials, including rocks and boulders that become detached from steep
slopes or cliffs.
• Debris Flows: Rapid mass movement of a combination of loose soil, rock, organic matter, air, and water that mobilize as a
slurry flowing down slope. These are most often caused by heavy precipitation and intense surface water runoff in steep
gullies.
• Mudflows: Earth flow consisting of material that is wet enough to flow rapidly and contains at least 50 percent sand, silt, and
clay sized particles. Mudflows can travel at speeds of 35 mph or greater.
• Creep: Imperceptibly slow, steady, downward movement of slope-forming soil or rock.
• The occurrence of landslides is determined by both natural and human factors. Natural factors include the cohesive strength
and shrink-well characteristics of the affected minerals, the orientation of joints and planes of weakness between slide material
and bedrock, the steepness of slopes, the degree of saturation of ground materials (highly affected by rainfall), and the density
of vegetation. Human factors include the over steepening and overloading of slopes, the removal of natural vegetation, and the
addition of water to the soil by watering of lawns and septic system drain fields, and onsite ponding of storm runoff.
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Hazard History
Numerous minor landslides have occurred in Sonoma County in areas adjacent to Rohnert Park. However, due to Rohnert Park’s
relatively flat topography, and the relative stability of the hillsides immediately adjacent to the City, any impacts from landslides
outside the city limits are anticipated to be indirect and/or minor.
Hazard Vulnerability and Risk
Assessment
The landslide risk in Rohnert
Park is largely outside the City
(See Figure 3.22). All of Rohnert
Park, and its critical facilities are
located in relatively flat areas
within the City limits, and none
are considered to be at high risk.
Figure 3.22: Landslide Risk
around Rohnert Park
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Dam Inundation
Hazard Description
The US Army Corps of Engineers built Warm Springs Dam
across Dry Creek. Completed in 1982, this rolled-earth
embankment dam is 319 feet (97 m) high, 3,000 feet (900 m)
long, and 30 feet (9 m) wide at the top. It contains
30,000,000 cubic yards (23,000,000 m3) of earth. The dam
aids in flood control, and a hydroelectric plant produces
electricity from the water released downstream. A minimum
amount of flow must be maintained in Dry Creek to
allow fish migration.
Hazard Vulnerability and Risk Assessment
The Warm Springs Dam was assessed in 2006 and, after
considering probability of failure and potential failure consequences, categorized it as being in Dam Safety Action Class (DSAC) IV
based upon the Dam Safety risk. Dams in Class IV are considered to be marginally safe, in that the combination of life or economic
consequences with probability of failure is low. No potential failure modes were identified using existing data.
Although no potential failure modes caused by flooding were identified, the consequences of a dam failure were analyzed. A relatively
low probability of failure along with a moderate sized downstream population, residential and commercial structures including
contents, roads, farm land, bridge damage, and utilities, has led to the dam’s inclusion in the DSAC IV category. The consequences
are judged to be similar for breaches caused by seepage, overtopping, or a seismic even. Portions of the communities of Healdsburg,
Windsor, Santa Rosa, Sebastopol, and Guerneville, as well as some rural population areas in the floodplain immediately downstream
of the dam, would be at risk if the dam failed as they are within the 1 to 24 hour flood wave travel time bracket. Half of the rural
population immediately downstream of the dam is important as -half are within a 15 minute flood wave travel time and all are within a
1 hour flood wave travel time. Based on the 2000 Census of Population and flood inundation maps, up to 84,854 people could be
impacted from a dam failure, with an estimated loss of life of up to 100 people from a maximum flood event. Damage includes
industrial and residential structures and their contents, roadways, infrastructure, agriculture (mainly viticulture), and bridge damage
along the Dry Creek. The estimated damages are up to $13 billion, including $219 million for repairing the dam. Potential inundation
areas are found in the County map in the Appendix. Only minor impacts are expected in the worst case scenario along the western
edge of Rohnert Park.
Figure 3.23: Warm Springs Dam at Lake Sonoma
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Earthquake Faulting
Hazard Description
Surface fault ruptures can result from large magnitude earthquakes.
Surface rupture occurs when movement on a fault deep within the earth
breaks through to the surface. Structures located within the fault rupture
zone are subjected to excessive ground deformations. Most structures are
not designed to withstand such large deformations and experience major
damage. Pipelines crossing the fault zones can also be damaged by the
stresses. During the 1906 San Francisco earthquake horizontal
displacement along the San Andreas Fault averaged 15 feet in Sonoma
County. The Healdsburg, Rodgers Creek and Maacama faults also show
evidence of surface displacement during the past 11,000 years.
Surface rupture is the most easily avoided seismic hazard. The Alquist-
Priolo Earthquake Fault Zoning Act was passed in 1972 to mitigate the
hazard of surface faulting to structures for human occupancy. Its main
purpose is to prevent the construction of buildings used for human
occupancy on the surface trace of active faults. It requires projects to
conduct a geologic investigation to demonstrate that proposed buildings
will not be constructed across active faults. A structure for human
occupancy cannot be placed over the trace of the fault and must be set
back from the fault (generally 50 feet).
Hazard Types
Earthquake Faults: A fault is a fracture along between blocks of the earth’s crust where either side moves relative to the other.
Strike-slip: Strike-slip faults are vertical or almost vertical rifts where the earth’s plates move mostly horizontally. From the
observer’s perspective, if the opposite block looking across the fault moves to the right, the slip style is called a right lateral fault; if
the block moves left, the shift is called a left lateral fault.
Figure 3.24: Earthquake Hazards in California
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Dip-slip: Dip-slip faults are
slanted fractures where the
blocks mostly shift
vertically. If the earth above
an inclined fault moves
down, the fault is called a
normal fault, but when the
rock above the fault moves
up, the fault is called a
reverse fault. Thrust faults
have a reverse fault with a
dip of 45 ° or less.
Hazard Vulnerability and Risk
Assessment
No known faults are located
in Rohnert Park. The
Rodgers Creek/Hayward
Fault Zone is several miles
east of the City limits, and
could potentially sever Crane
Canyon Road –
disconnecting the City’s
direct link to the Bennett
Valley area (See Figure
3.25).
Figure 1.1 Risk Assessment Concept
Figure 3.25: Location of nearest fault zone to Rohnert Park
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Summary of Vulnerabilities
This Table identifies the Critical Facilities that are at
risk from potential hazards. The facilities are classified
into separate categories including Government Center,
Community, Fire, Health, Parks, and Schools. Facilities
with more than a low level risk to specific hazard are
denoted accordingly and shaded in orange. As landslide,
and hazardous material risks are low throughout the
community they are omitted from the table.
Primary Vulnerabilities
• Localized Flooding (based on local
experiences from winter storms)
• Flooding based on FEMA 100 and 500 Year
Flood Event Maps
• Earthquake Shaking
• Earthquake Liquefaction
• Drought
• Wildland-Urban Interface Fire
Secondary Vulnerabilities
• Dam Inundation
• Landslides
• Hazardous Materials
• Earthquake Fault Ruptures
Figure 3.26: Winter storm induced flooding on Commerce Blvd.
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Vulnerability Analysis of Critical Facilities
This analysis was conducted by analyzing the location of these facilities in relation to the relative likelihood and intensity of the
potential hazards that could impact them. The table does not include several potential hazards that affect only a few select areas or
facilities in Rohnert Park (such as dam inundation), nor potential hazards that pose only a low level of vulnerability in Rohnert Park
(such as Hazardous Materials). Similarly, landslides, and earthquake faulting are not included in this table as they do not have the
potentially to directly impact the City of Rohnert Park (though there is the potential of secondary impacts from these hazards).
Table 4.1: Vulnerability Analysis
Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
City Properties
City Hall
130 Avram
Avenue
Government
Center High High Medium
Corporation
Yard (Public
Works)
600 Enterprise
Drive Public Works High Medium
Senior Center
6800 Hunter
Drive Community Medium High Medium
Community
Center
5401 Snyder
Lane Community Medium High Medium
Burton Avenue
Recreation
Center
7421 Burton
Avenue Community High Medium
Spreckels
Performing Arts
Center
5409 Snyder
Lane Community Medium High Medium
Callinan
Recreation
Center
5405 Snyder
Lane Community High Medium
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Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
Animal Shelter
301 J Rogers
Lane Community High Medium
Pump Facility
201 J Rogers
Lane Public Works Medium High Medium
Public Safety
Facility (Main)
500 City
Center Drive
Government
Center High Medium
Fire Station 2
(North)
5200 Country
Club Drive Fire High Medium
Fire Station 3
(West) (Future)
5870 Labath
Avenue Fire High Medium
Fire Station 4
(South)
1312 Maurice
Avenue Fire High Medium
State Farm
Expressway
Landscaping
State Farm
Expressway Public Works High Medium Medium
Enterprise
Avenue
Landscaping
Enterprise
Avenue Public Works Medium High Medium Medium
Water Tanks
Various
Locations Public Works High High High Medium
Parks
Alicia Park
300 Arlen
Drive Park
Benicia Park
7471 Bernice
Avenue Pool
Benicia Pool
7421 Burton
Avenue Park High Medium
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Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
Caterpillar Park
7430 Circle
Drive Park Medium
Colegio Vista
1200
Southwest
Boulevard Park
Dorotea Park
895 Santa
Dorotea Park Park
Eagle Park
1115 Emily
Avenue Park High
Gold Ridge Park
1455 Golf
Course Drive Park High
Golis Park
1450 Golf
Course Drive Park Medium Medium High Medium
Honeybee Park
1170 Golf
Course Drive Park High Medium
Honeybee Pool
1170 Golf
Course Drive Pool High High Medium
Ladybug Park
8517 Liman
Way Park Medium
Magnolia Park
1401
Middlebrook Park
Magnolia Pool
1501
Middlebrook
Way Pool High Medium
Oak Grove Park
(Future) Keiser Avenue Park High High Medium
Rainbow Park
1345 Rosana
Way Park
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Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
Sunrise Park
5201 Snyder
Lane Park Medium High
Twin Creeks
Park Kerry Road Park High Medium
Willow Glen
Park (Future)
Bodway
Parkway Park High
Robert's Lake
5010 Robert's
Lake Road Park High Medium
Rohnert Bark
(Dog Park)
5010 Robert's
Lake Road Park
Field Of Friends
(Dog Park)
7471 Bernice
Avenue Park
Creekside
Multi-Use Paths N/A
Multi-Use
Paths Medium Medium High High High
Municipal Golf
Course (North)
100 Golf
Course Drive Park High Medium Medium Medium
Municipal Golf
Course (South)
100 Golf
Course Drive Park Medium Medium
Non-City
Facilities
California
Highway Patrol
6100 Labath
Avenue State High Medium
SMART Station
N/A (Rohnert
Park
Expressway) Transportation High Medium
Sutter Pacific
1400 Medical
Center Drive Medical Medium Very High Medium
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Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
Kaiser
Permanente
5900 State
Farm Drive Medical High Medium
Rohnert Park
Cancer Center
301
Professional
Center Drive Medical High Medium
Schools
Marguerite
Hahn
Elementary
825 Hudis
Street School Very High Medium
Evergreen
Elementary
1125 Emily
Avenue School Very High Medium
Technology
Middle School
7165 Burton
Avenue School High Medium
Rancho Cotate
High School
5450 Snyder
Lane School Very High High
Monte Vista
Elementary
1400 Magnolia
Avenue School Very High Medium
Lawrence E.
Jones Middle
School
5154 Snyder
Lane School Medium Very High Medium Medium
Richard Crane
Elementary
1290
Southwest
Boulevard School High Medium
John Reed
Elementary
390 Arlen
Drive School High Medium
Waldo Rohnert
Elementary
550 Bonnie
Avenue School High Medium
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Facility Address Facility Type
Flood
(Local)
Flood
(FEMA)
Earthquake
(Shaking)
Earthquake
(Liquefaction) Drought
WUI-
Fire
Technology
High School
1801 East
Cotati Avenue School Very High High
La Fiesta
Elementary
8511 Liman
Way School High Medium
Sonoma State
University
1801 East
Cotati Avenue University Very High High Medium
Credo High
School
1300 Valley
House Drive School Medium Medium Medium
Mobile
Home/RV
Parks
Rancho Verde
650 Rohnert
Park
Expressway
Mobile Home
Park
Very
High
Very
High High Medium Medium
Rancho Grande
5099 Snyder
Lane
Mobile Home
Park Medium Very High Medium Medium Medium
Rancho Feliz
6607 Redwood
Drive
Mobile Home
Park Medium High Medium Medium
Valley Village
6401 Country
Club Drive
Mobile Home
Park High High Medium
Las Casitas
7545 Bridget
Drive
Mobile Home
Park High Medium
Wine Country
RV Park
7450 Cristobal
Way RV Park High Medium
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Table 4.2: Infrastructure Vulnerability and Exposure
Hazard Roads
(miles)
Rail/Transit
(miles)
Total Miles of Infrastructure 130 4
Earthquake Shaking (within highest two shaking categories) 130 4
Liquefaction Susceptibility (within moderate, high, or very high liquefaction susceptibility 130 4
Earthquake-Induced Landslides 0 0
Earthquake Faulting 0 0
Flooding (within 100 year floodplain) 6 0
Flooding (within 500 year floodplain) 5 0
Landslides (within areas of existing landslides) None None
Wildfires (subject to high, very high, or extreme wildfire threat) None None
Wildland-Urban Interface Fire Threat 17 1
Dam Inundation (within inundation zone) <1 0
Potential Impacts to Critical Facilities from Earthquake
Bed Loss in Hospitals
The City of Rohnert Park has two medical facilities; Kaiser Permanente on State Farm Drive and St. Joseph’s Urgent Care Center on
Medical Center Drive. There are a total of eight major medical facilities within Sonoma County. Public service agencies and volunteer
personnel would be used to assist in the care of the injured.
Several of the acute care hospitals in Sonoma County may be lost due to structural damage. In addition, even the most modern
hospitals can be incapacitated by non-structural damage. Earthquake shaking can damage sensitive equipment, topple storage units,
and dislodge ceilings or light fixtures. Damage to water pipes could flood portions of buildings. Damage can be serious, and it can
cause major areas within hospitals to be nonfunctional during the critical hours immediately following a major quake. This will
decrease the number of beds available and create the need for alternate treatment facilities or field hospitals. Although a percentage of
the remaining beds could be made available by discharging or transferring non-emergency patients, it will probably be necessary to
receive an immediate influx of emergency medical aid and/or export some of the seriously injured to out-of-county facilities.
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Building Survivability
An earthquake could shake all parts of the City of Rohnert Park and Sonoma County. Every building in the City is exposed to high
risk of damage in earthquakes by virtue of being located in a seismically active part of the country. Some of these structures face an
elevated risk because they are located in high hazard zones, such as near the fault, on liquefiable soils, or on slopes subject to
landslides. Other structures face high risk because their construction quality is inadequate to withstand strong shaking, primarily
because they were built decades ago before modern building codes were enacted. Some structures house critical City and County
functions, such as emergency response activities, and it is important that these structures remain functional after an earthquake.
Communications
System failure, overloads, loss of electrical power and possible failure of some alternate power systems will affect telephone and
cellular systems. Numerous failures can be expected to occur, and the systems will be overloaded beyond capacity. The anticipated
damage could disable up to 80% of the telephone system for one day. In light of this, emergency planners should not expect the use of
telephone or cellular systems for the first few days after the event.
The City of Rohnert Park and Sonoma County as a whole have a wireless communications network used for public safety and
emergency response. The communications network is used by the County and City agencies, public safety officials and emergency
responders. The network is comprised of remote mountain top communication sites, consisting of towers and equipment buildings,
which provide wireless communications coverage throughout Sonoma County. While the communications system is designed to be
functional even after the loss of one or more antennas, a major earthquake impacting multiple sites could significantly reduce
communications effectiveness.
Electrical Power
Major power plants are expected to sustain some damage due to liquefaction and the intensity of the earthquake. Up to 60% of the
system load may be interrupted immediately following the initial shock. According to representatives of PG&E, electrical power may
not be rerouted, resulting in wide spread outages for an undefined period of time. A great deal of the imported power is expected to be
lost. In areas of greatest shaking, it should be anticipated that some distribution lines, both underground and surface, would be
damaged. Much of the affected area may have service restored in days; areas that suffer extensive damage or have underground
distribution may require a longer time.
Fire Operations
Although total collapse of fire stations is not expected, possible disruption of utilities, twisted doors and loss of power can create
major problems. Numerous fires due to disruption of power and natural gas networks can be expected. Many connections to major
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water sources may be damaged and storage facilities would have to be relied on; water pressure and supply could be inadequate to
non-existent. First response from fire personnel is expected to be damage assessment and determining resources needed for response
and recovery needs. Response could be further complicated and delayed by the disruption of transportation routes.
Secondary responses by the fire service will focus on search and rescue of trapped persons. Rescuers should expect loss of power and
water, jammed doors, restricted mobility due to debris, possible loss of communications capability and delays in reaching maximum
effectiveness due to personnel shortages.
Roads, Highways and Bridges
Many roads in the County of Sonoma traverse areas subject to liquefaction and landslides. Roadways that experience liquefaction can
develop very large cracks that prevent their use, and can develop smaller cracks and sinkholes that impede traffic. Landslides triggered
by earthquakes can both block and rip out sections of roads. Numerous roads will be subject to delays and detours. Damage to freeway
systems is expected to be major, despite seismic upgrades. Portions of surface streets in the vicinity of freeways may be blocked due
to collapsed overpasses. Many surface streets in the older central business district will be blocked by debris from buildings, falling
electrical wires and pavement damage. Local bridges that have not been seismically retrofitted may experience a high percentage of
failure. The failures of major roadways in the county could impact safe routes for mutual aid resources responding to the City of
Rohnert Park.
Sanitation Systems
Many of the wastewater treatment facilities could be disrupted, depending on the severity and intensity of the earthquake and damage
caused by liquefaction. There is a limited amount of storage available in the wastewater treatment plants; if the treatment train cannot
be restored before the storage is exceeded, wastewater will require discharge with emergency chlorination to reduce health hazards.
Overflow of sewage through manholes and from ponds can be expected due to breaks in sewer mains and loss of power. As a result,
there may be danger of excessive collection of explosive gas in sewer mains, and flow of untreated sewage in some street gutters.
Many house sewer connections will break and plug.
Water Supply
Several ruptures are anticipated along the water pipelines in the City and County Areas. A majority of water wells are expected to be
disabled by loss of electricity and the lack of backup power sources. In addition, shear forces could render about a third of the wells
inoperative for an indefinite period. Water availability and distribution for needed life support, to treat the sick and injured and for fire
suppression activities is of major concern to each community.
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Social Vulnerability Analysis
A hazard event has the potential to effect members of the community in varying ways, even if the extent and severity of the hazard is
precisely the same. In some cases, an earthquake event may be more impactful and damaging to persons of lower income, as they are
more likely to lack the financial resources to have retrofitted their home to be more resistant and resilient to ground shaking. A
community member’s vulnerability to a hazard situation could also be affected by other factors such as age, disability status,
education, English proficiency, or other factors. Together, these factors reflect a community member’s vulnerability independent of
the hazard or disaster itself. This is known as social vulnerability.
Table 4.3 Community-Wide Social Vulnerability Metrics
Social Vulnerability Metric Totals
Number of residents 42, 622
Number of households 15,808
Number of households with children 4,363
Median household income $58,317
Percentage of households under the poverty limit 15.2%
Number of elderly households 3,048
Number of adults without a high school diploma 3,072
Percentage of people with limited English proficiency 9.5%
Percentage of households with a disabled family member 12.5%
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
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MITIGATION AND ADAPTATION STRATEGY
The purpose of hazard mitigation is to reduce potential losses from future disasters. The intent of mitigation planning, therefore, is to
maintain a process that leads to hazard mitigation actions. Mitigation plans identify the natural hazards that impact communities,
identify actions to reduce losses from those hazards, and establish a coordinated process to implement the plan. (44 CFR §201.1(b))
The findings of the vulnerability and risk assessments in the previous chapter were used to develop actions that reduce and/or
eliminate potential losses from relevant hazards.
FEMA Element C: Mitigation Strategy
• C1. Does the plan document each jurisdiction’s existing authorities, policies, programs and resources, and its ability to expand
on and improve these existing policies and programs? 44 CFR 201.6(c)(3)
• C2. Does the Plan address each jurisdiction’s participation in the NFIP and continued compliance with NFIP requirements, as
appropriate? 44 CFR 201.6(c)(3)(ii)
• C3. Does the Plan include goals to reduce/avoid long‐term vulnerabilities to the identified hazards? 44 CFR 201.6(c)(3)(i)
• C4. Does the Plan identify and analyze a comprehensive range of specific mitigation actions and projects for each jurisdiction
being considered to reduce the effects of hazards, with emphasis on new and existing buildings and infrastructure? 44 CFR
201.6(c)(3)(ii) and 44 CFR 201.6(c)(3)(iv)
• C5. Does the Plan contain an action plan that describes how the actions identified will be prioritized (including cost benefit
review), implemented, and administered by each jurisdiction? 44 CFR 201.6(c)(3)(iii) and 44 CFR (c)(3)(iv)
• C6. Does the Plan describe a process by which local governments will integrate the requirements of the mitigation plan into
other planning mechanisms, such as comprehensive or capital improvement plans, when appropriate? 44 CFR 201.6(c)(4)(ii)
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
ROHNERT PARK - LHMP 82
Hazard Mitigation Goals, Priorities, Benefits narrative
The City of Rohnert Park established LHMP mitigation priorities and goals as a component of the planning process in order to guide
the development of a thorough plan. The goals were developed by the planning team and drawn from the previous LHMP and the
City’s General Plan. The mitigation goals and priorities for the LHMP are:
The City’s hazard mitigation goals are intended to develop effective policy choices that protect community members, property,
infrastructure, and natural resources from hazards. These goals shape the mitigation actions taken by the City and the community to
reduce the risks from natural disasters, and act as a checkpoint that City departments can use to check on the progress of mitigation
actions and implementation.
1. Implement the Local Hazard Mitigation Plan to increase Rohnert Park’s level of preparation for potential disasters and
to minimize the impacts associated with natural and man-made hazards.
2. Identify strategies and tools to facilitate community disaster and hazards awareness and education.
3. Provide for the safety of Rohnert Park citizens by maintaining efficient, well-trained, and adequately equipped City
personnel.
4. Encourage a disaster-resistant City and surrounding area by reducing the potential for loss of life, property damage,
and environmental degradation from disasters and hazards.
5. Reduce the vulnerability of public and private facilities and infrastructure to the effects of earthquakes, flooding, and
drought.
6. Promote conditions and strategies that will accelerate the capacity for physical and economic recovery from disasters
and hazards.
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
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Mitigation Goals and Mitigation Actions Development
The LHMP Team met several times to discuss hazard mitigation goals and hazard mitigation actions. The Team looked at the risks
and vulnerabilities identified in previous sections of this plan. While generally goals did exist with the 2010 Annex, new goals were
formulated and identified for the new LHMP. After mitigation goals were completed, hazards identified and described, and risk
assessed, the LHMP Team prepared draft actions, and revised and prioritized them based on data analysis and local knowledge about
the risks and priorities associated with each hazard. FEMA directs local governments to use the following criteria as part of its
evaluation of mitigation actions:
• The frequency and severity of individual hazard types, and the vulnerability of the community to these hazards
• The impacts reduced or avoided by the action
• The amount of benefits provided by the action
• The critical facilities benefited by the action, including the number of facilities and their importance
• The environmental benefits of the action
Figure 5.1 and 5.2: Mitigation Goals and Mitigation Actions Process
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
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The LHMP Team also reviewed the proposed mitigation actions in terms of considering of the STAPLE/E (Social, Technical,
Administrative, Political, Legal, Economic, and Environmental) criteria. The team did not conduct a formal SAPLE/E analysis, but
considered these criteria as part of the evaluation process and discussed how the STAPLE/E criteria may be used to evaluate any grant
applications the City of Rohnert Park may submit to assist with LHMP implementation.
Table 5.1 STAPLE/E Criteria
Issue Criteria
Social • Is the measure socially acceptable to City residents?
• Would the measure treat some individuals unfairly?
• Could the measure reasonably cause potential social disruption?
Technical • Is the measure likely to reduce the risk from a hazard, or will it only reduce the consequences of the risk?
• Will the measure create more problems or exacerbate existing ones?
• Is the measure the most useful course of action to address the risk, given the goals of the City?
Administrative • Does the City have the administrative capabilities to implement the measure?
• Is the City’s staff available to coordinate and lead implementation of the measure?
• Does the City have sufficient technical support, staff, and funding for implementation?
• Dos the City face administrative barriers to implementation?
Political • Is the measure politically acceptable to the City and to other jurisdictions within the City’s borders?
• Do community members support beginning and or/continuing measure implementation?
Legal • Does the City have the authority to implement the measure and enforce it as needed?
• Are there potential legal consequences or barriers that could reasonably hinder measure implementation?
• Could the measure expose the City to legal liabilities?
• Could the measure reasonably face legal challenges?
Economic • What are the monetary costs of the measure, and do these costs exceed the monetary benefits?
• What are the start-up, maintenance, and administrative costs associated with the measure?
• Has funding for the measure been secured, or is there a source of funding available?
• How will the measure affect the City’s financial capabilities?
• Will the measure reasonably place any potential burden on the local economy or tax base?
• What are the budgetary and revenue effects of the measure to the City?
Environmental • How will the measure effect the environment?
• Will the measure need environmental regulatory approvals?
• Will the measure reasonably affect any endangered, threatened or otherwise sensitive species?
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
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2010 Hazard Mitigation priorities and Actions
As the City embarked on the hazard mitigation planning process, the Planning Team reviewed the mitigation priorities and actions
previously prepared and adopted as part of the City’s Annex to the 2010 ABAG LHMP. Appendix D provides the previous mitigation
actions from the 2010 Plan. As part of the planning process in 2010, the actions were written very generally so as to apply to the
region. The newly developed mitigation goals and actions are more carefully tailored to better fit the City’s unique needs. As the new
mitigation actions are more specific it will be easier to measure and track progress towards them going forward.
Hazard Mitigation Cost – Benefit Review
Local governments are required to consider the costs and benefits of a full range of mitigation activities that can be implemented to
reduce the potential effects of a particular hazard within the specific community. Cost-benefit analysis is generally used in hazard
mitigation to provide guidance on whether the benefits to life and property protected through mitigation efforts have the potential
outweigh the costs of the associated mitigation action. The conducting of a cost-benefit review for a particular mitigation activity has
the ability to assist communities in determining whether a project is substantially worth undertaking in order to minimize or even
avoid damages later on.
An LHMP must demonstrate that a process was employed that emphasized a substantial review of the cost-benefits when evaluating
and prioritizing mitigation actions. The cost-benefit review must be comprehensive enough in the way it reviews actions so that it can
sufficiently evaluate the monetary and non-monetary benefits and specific costs that are tied to each action.
Factors to be considered in a cost-benefit analysis:
• How large an area is potentially impacted?
• How many people are expected to benefit from the action?
• How do critical facilities and infrastructure benefit from the action?
• Does such an action make sense for the environment?
The LHMP Team used a simple method to estimate and determine the relative cost of mitigation activities. The following table
identifies the relative cost of mitigation actions, which uses three categories: $ - Indicates Low Cost (<$50,000), $$ - Indicates Medium
Cost ($50,000-$100,000), and $$$ - Indicates High Cost (>$100,000). During the City’s implementing period, and annual review of the
plan, more specific costs will be determined, and the cost-benefit matrix refined as necessary.
CITY OF ROHNERT PARK - 2017 LOCAL HAZARD MITIGATION PLAN
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Mitigation Actions
The Rohnert Park LHMP Team utilized data from the Hazard Profiles and Vulnerability Assessment, Capabilities Assessment, and
progress on past actions to formulate Mitigation Actions for the new LHMP. Table 5.2 below identifies the proposed mitigation
actions, who the responsible city department would be, some potential funding sources, the individual action’s overall priority and
goal completion date, which mitigation goal the action fulfills, and the relative cost: $=low, $$=medium, $$$=high.
The following abbreviations are used in the table:
• Dev. Services: Rohnert Park Development Services Department (includes Planning, Engineering, and Building).
• Admin.: Rohnert Park Administration
• Public Safety: Rohnert Park Department of Public Safety (combined police and fire)
• I.T.: Rohnert Park Information Technology
• Public Works: Rohnert Park Department of Public Works
• HMGP: Hazard Mitigation Grant Program
• FMA: Flood Mitigation Grant Program
• PDM: Pre-Disaster Mitigation Grant Program
• FMAG: Fire Management Assistance Grant Program
Table 5.2: Mitigation Actions
Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
1. Multiple Hazards - Related Actions
1.1 Continue to apply appropriate
development conditions/restrictions for
projects in higher hazards zones to reduce
risks
Dev. Services,
Public Safety
General
Fund,
HMGP,
PDM, Cost
Recovery
Ongoing High 4 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
1.2 Continue to analyze and improve
emergency response communication. This
strategy should include building redundant
capacity into public safety alerting, and
answering points as well as replacing or
hardening communication systems. Use the
City website and social media for
community outreach purposes.
Admin.,
Public Safety,
I.T.
General
Fund,
HMGP,
PDM,
FMAG,
Other
Grant
Sources
2019 Low 2, 3, 4 $
1.3 Continue to assess critical facilities that are
vulnerable to damage from natural
disasters, including availability of backup
power and sufficient supplies to maintain
essential functions, and make
recommendations for appropriate
mitigation.
Dev. Services,
Public Safety,
Public Works
General
Fund,
HMPG,
PDM,
Other
Grant
Resources
2018 High 5, 6 $
1.4 Retrofit, replace, or relocate critical
facilities that are shown to be vulnerable to
damage in natural disasters.
Public Works General
Fund,
HMGP,
PDM, Cost
Recovery
Ongoing Moderate 4, 5,6 $$$
1.5 Continue to participate not only in general
mutual-aid agreements, but also in
agreements with adjoining jurisdictions and
special districts for cooperative response to
fires, floods, earthquakes, and other
disasters.
Public Safety General
Fund,
HMGP,
PDM,
Other
Grant
Sources
Ongoing Low 1, 2 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
1.6 In accordance with the adaptation
strategies of the Sonoma County Climate
Action Plan (SCCAP) continue to regularly
inform, and solicit feedback from City
organizations on potential climate change
risks, and hazards with all departments as
relevant.
Dev. Services,
Public Safety,
Public Works
General
Fund, Cost
Recovery
Ongoing Moderate 2, 4 $
1.7 In accordance with the adaptation
strategies of the SCCAP, revise Rohnert
Park's General Plan, and other applicable
documents to better integrate, and
prioritize climate change issues, and best
practices during required updates and as
funding opportunities permit.
Dev. Services General
Fund, Cost
Recovery
Ongoing High 2, 4, 6 $$
1.8 In accordance with the adaptation
strategies of the SCCAP, integrate climate
change adaptation into future updates of
the Zoning Code and General Plan, and
other related documents.
Dev. Services General
Fund,
Other
Grant
Sources
Ongoing High 2, 4, 6 $$
1.9 Continue to coordinate with Sonoma
County, and surrounding jurisdictions on
emergency notifications, including alerts of
imminent threats or a need to evacuate.
Public Safety General
Fund,
Other
Grant
Sources,
PDM,
HMPG
Ongoing Moderate 1, 2, 3 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
1.11 To the extent possible, avoid locating new
critical facilities in areas of elevated hazard
risks. Use extensive mitigation measures to
reduce vulnerability if no suitable
alternative site exists.
Dev. Services General
Fund, Cost
recovery
Ongoing Low 4, 5 $
1.12 Continue to work with regional companies
and service agencies, including energy
providers, telecommunications services,
and transit operators, to maintain basic
services as much as possible during
emergency conditions and to restore
services as quickly as possible following an
emergency event.
Public Safety,
Public Works
General
Fund,
PDM,
HMGP
Ongoing Low 4, 5, 6 $
1.13 Work to improve estimates of potential
casualties and property damage as a result
of different emergency situations.
Dev. Services,
Public Safety
General
Fund,
HMPG,
PDM,
Other
Grant
Resources
2019 Low 1, 4, 6 $$
1.14 Continue to update the City's emergency
planning documents to ensure consistency
with state and federal law, local conditions,
best practices, and most recent science and
technology.
Dev. Services,
Public Works,
Public Safety
General
Fund,
General
Plan
Maintena
nce Fund
2018 High 1, 2, 4 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
1.15 Continue to improve the reliability of the
water supply for emergency response
purposes through new water main
connections and system improvements.
Dev.
Services,
Public
Works,
Public Safety
General
Fund, Cost
Recovery,
Other
Grant
Sources
Ongoing Moderate 4, 5, 6 $$
1.16 Invest in continued training for City staff in
emergency preparedness and response.
All
Departments
Other
Grant
Sources,
PDM,
HMPG
Ongoing Low 3 $$
1.17 Continue to make strategic investments in
modern equipment for City staff.
All
Departments
General
Fund,
Other
Grant
Sources
Ongoing Moderate 2, 3, 6 $$
1.18 Continue to maintain and periodically
update the LHMP.
All
Departments
General
Fund,
PDM,
HMPG
Ongoing High 1, 2 $$
2. Flooding
2.1 Sustain the City's participation in FEMA's
National Flood Insurance program (NFIP).
Dev. Services,
Public Works,
Public Safety
General
Fund,
Other
Grant
Sources
Ongoing High 1, 4, 5, 6 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
2.2 When FEMA creates, updates, and
publishes flood zone mapping of the 100-
year and 500-year floodplains, quickly
integrate new information from the maps
into the City's GIS, and use flood
information in the development review and
public project review process. In areas with
high flood risk, continue to evaluate, and
implement flood hazard mitigation projects
to reduce potential for property damage,
street flooding, and stream erosion.
Dev. Services,
Public Works
General
Fund,
Other
Grant
Sources
Ongoing High 1, 4, 5 $$
2.3 Continue to analyze pump station
conditions, capacity, and upgrades when
appropriate.
Public Works General
Fund,
Developm
ent Fees
Ongoing Low 3, 4, 5, 6 $$
2.4 Evaluate, monitor, and maintain the City's
storm water drainage system to ensure it
can effectively handle anticipated storm
water volumes to the maximum extent
possible, and make upgrades and repairs as
needed. Coordinate with the Sonoma
County Water Agency to clear debris, and
remove vegetation and sediment in flood
control channels within the City to protect
flow capacity.
Public Works General
Fund,
Other
Grant
Resources
Ongoing Moderate 1, 4, 5 $$
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
2.5 Continue to pursue grant funding to
complete creek restoration projects that
result in bank stabilization, enhanced
habitat, and flood capacity.
Public Works,
Dev. Services
Other
Grant
Resources
Ongoing Low 4, 5 $$
2.6 Retrofit public areas, including plazas,
sidewalks, and parking lots as feasible, to
use permeable paving and other low-
impact development features that promote
infiltration, and reduce storm water runoff.
Public Works General
Fund,
Other
Grant
Resources
Ongoing Low 4, 5 $$$
2.7 Continue to pursue project to mitigate
downstream flooding through the
preservation, and construction of regional
drainage basins.
Public Works,
Dev. Services
General
Fund,
Developm
ent Fees,
Other
Grant
Sources
Ongoing Moderate 5 $$
3. Seismic Hazards (Shaking)
3.1 Consider the development of funding
mechanisms to assist building owners’
affordability of retrofits to unreinforced or
retrofitted structures.
Dev. Services TBD TBD Low 2, 4, 5 $$
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
3.2 Require the retrofit of seismically
vulnerable structures consistent with City
Code at the time of major renovations or
redevelopment. This program should
include community education and
outreach.
Dev. Services General
Fund
Ongoing Low 4, 5, 6 $$
3.3 Identify/analyze sewer and water lines that
are determined to be structurally deficient,
and retrofit and replace as necessary.
Public Works General
Fund,
Developm
ent Fees,
HMPG,
PDM,
Other
Grant
Resources
2019 Low 5, 6 $$$
3.4 Conduct seismic evaluations of City-owned
properties that contain critical
facilities/operations to determine the need
for upgrades/retrofitting.
Dev. Services,
Public Works
TBD 2019 Moderate 1, 3, 4, 5 $$$
4. Geologic Hazards (Liquefaction)
4.1 Require comprehensive geotechnical
investigations prior to development
approval, where applicable. Investigations
shall include evaluation of liquefaction
potential, settlement, seismically induced
land-sliding, or weak and expansive soils.
Dev. Services Developm
ent Fees
Ongoing Moderate 1, 4, 5 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
4.2 Restrict development from areas where
people might be adversely affected by
natural or man-made geologic hazards,
including unstable slopes, liquefiable or
expansive soils, and poorly engineered fills,
as determined by a California-registered
geologist or engineer.
Dev. Services General
Fund,
General
Plan
Maintena
nce Fund
Ongoing High 4, 5, 6 $$
4.3 Pursue implementation of regulatory
requirements related to erosion and
sediment control. As needed, adopt
additional, mandatory, minimum sediment
and erosion control measures for current
properties, and those under construction
that exhibit high erosion potential or have
experience past erosion problems.
Sediment and erosion control measures
shall reduce soil erosion from primary
erosional agents including wind,
construction operations, and storm water
runoff.
Dev. Services TBD 2019 Low 5 $$
4.4 Identify grant programs, and other funding
opportunities to retrofit soft-stories.
Dev. Services TBD 2019 Low 4, 5 $$
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
5. Hazardous Materials
5.1 Provide reliable water delivery, and
wastewater collection during, and after
disasters to reduce the risk to public health,
and the environment.
Public Works General
Fund,
Other
Grant
Resources
,
Developm
ent Fees
Ongoing High 4, 5, 6 $$$
5.2 Generate, and support public awareness,
and participation in household waste
management, control, and recycling.
Public Safety General
Fund,
Other
Grant
Resources
Ongoing Low 1, 2 $
5.3 Continue to improve the capabilities of the
Public Safety Department to respond to
new hazardous material
incidents/emergencies.
Public Safety General
Fund,
Other
Grant
Resources
Ongoing Moderate 1, 2, 3 $$
5.4 Update the HazMat Response Plan. Public Safety General
Fund,
Other
Grant
Resources
2019 Low 2, 4, 6 $$
5.5 Develop strategies to enhance protection
of existing groundwater resources from
hazardous material sites.
Public Safety,
Public Works
TBD 2018 Moderate 2, 4, 5 $$
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
5.6 Continue to improve outreach to
businesses that store, handle, and use
hazardous materials over the state
threshold or generate hazardous waste.
Public Safety,
Public Works
General
Fund,
HMPG,
PDM,
Other
Grant
Resources
Ongoing Low 1, 2, 4 $
6. Drought
6.1 Continue to participate in the Russian River
Watershed Association to provide water
conservation guidance, encourage drought-
tolerant landscaping, and reduce the
consumption of potable water.
Public Works General
Fund
Ongoing Low 1, 2, 4 $
6.2 Continue to wisely use, where available,
water resources from the recycled water
system.
Dev. Services,
Public Works
General
Fund,
Developm
ent Fees
Ongoing High 4, 5 $$
6.3 Develop a plan for expediting the repair,
and functional restoration of water, and
wastewater systems through the
stockpiling of materials, temporary pumps,
surface pipelines, portable hydrants, and
other supplies.
Public Works TBD 2019 Low 5, 6 $$
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
6.4 Host regular workshops, and classes on
water conservation strategies, including
drought-tolerant landscaping. Available
rebates for water conservation, and water
efficiency actions. Continue workshops,
classes and other education efforts even in
the absence of drought conditions.
Public Works General
Fund,
Other
Grant
Resources
TBD Low 1, 2, 4 $
7. Dam Inundation
7.1 Utilize mapping tools to better understand
potential impacts of dam failure on the
recently annexed Northwest Specific Plan
Area and areas along creeks west of
Highway 101 that drain in to the Laguna de
Santa Rosa.
Public Works,
Development
Services
General
Fund, CID,
Other
Grant
Resources
2019 Moderate 4, 5 $
8. Landslides and Earthquake Faulting
8.1 Prepare a report based on mapping
activities documenting potential secondary
impacts of landslides and earthquake fault
ruptures on transportation infrastructure,
utilities, and communications facilities that
service Rohnert Park.
Public Works,
Development
Services
General
Fund
2019 Low 4, 5 $$
8.2 Assess the potential impact of fire damage
triggered landslides and debris on property
and streams within the City of Rohnert Park
Public Works,
development
Services
Other
Grant
Resources
2018 High 4, 5 $
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Mitigation Action Responsible
Department
Potential
Funding
Sources
Target
Complete
Date
Priority Mitigation
Goal
Relative
Cost
9. Wildland-Urban Interface Fire
9.1 Continue to monitor the Wildland-Urban
Interface areas of the City, and develop
maps and materials as a part of plan to
mitigate exposure to current and future fire
risks.
Public Safety,
Dev. Services
FMAG,
Other
Grant
Resources
2018 High 1, 4, 5 $$
9.2 Map properties that were impacted by the
October 2017 fires, either directly, or
through Emergency Operations activities,
and assess needs and methods for future
access and emergency response.
Public Safety,
Public Works,
Dev. Services
FMAG,
Other
Grant
Resources
2018 High 1, 4, 5 $
9.3 Assess what additional equipment,
resources, or authority may be needed to
mitigate the risk of future fire emergencies,
and to respond effectively in the event one
occurs.
Admin.,
Public Safety,
Public Works,
Dev. Services
FMAG,
General
Fund,
Other
Grant
Resources
2018 High 1, 4, 5 $$
$ Indicates Low Cost (<$50,000)
$$ Indicates Medium Cost ($50,000-$100,000)
$$$ Indicates High Cost (>$100,000)
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Implementation of Select Mitigation Actions
Stream Maintenance to Reduce Flooding Impacts: In Rohnert Park,
the Sonoma County Water Agency (SCWA) performs periodic channel
maintenance activities which may include sediment removal, debris
removal, and vegetation maintenance. Though initially designed and
built as constructed channels to move stormwater and other runoff
through and away from developed land, the waterways that traverse the
City are thought of by many as creeks -- assets with value beyond
storm water conveyance. Responding to this changing approach,
SCWA is moving away from the dredging and clearing activities of the
past, and has developed a Stream Maintenance Program that is its new
channel maintenance strategy.
Rohnert Park’s Low Impact Development Strategy: Low Impact
Development (LID) is defined as a design strategy to maintain or
reproduce the way storm water infiltrates or runs off a site before
development occurs. LID principles control storm water runoff by
using small scale landscape based features that are distributed
throughout the site. Projects designed following LID principles must maintain the undeveloped volume of storm water runoff and
mimic the natural water balance through infiltration, evapo-transpiration, or through capture and reuse of storm water.
LID is intended to minimize the impact of development —our buildings, roads, parking lots, driveways— on our watersheds. LID
correlates the relationship between storm water runoff and the land, including our built environment. LID techniques lessen the
quantity of runoff and improve its quality by "slowing, spreading, or sinking" runoff on the site as much as possible. Slowing down
storm water runoff keeps the water in the channels from rising too high and too fast and devastating communities downstream.
Spreading does the same, helping to dissipate the storm water's power. Sinking means infiltrating water through soil, which cleans the
water and recharges the groundwater table.
The City's MS4 permit requires compliance with the City of Santa Rosa and County of Sonoma's LID Technical Design Manual
(dated August 2011). Adherence to these guidelines requires new development projects to incorporate LID design strategies and
BMPs to reduce pollutants in runoff to the maximum extent practicable. The LID manual was updated and in effect as of 2017.
Figure 5.3: 2017 SCWA Stream Maintenance
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Capabilities Assessment
An LHMP is required to conduct a capabilities assessment to
identify local personnel, agencies, and resources that have the
capability and capacity to assist with and support hazard
mitigation activities. The LHMP Planning Team identified
and defined known local resources available to the City of
Rohnert Park. Many of these resources were used or consulted
in the development of this LHMP. They are briefly
summarized in Table 5.3 below.
Rohnert Park’s capabilities are, like any governmental
jurisdiction, constantly undergoing refinement and
improvement. The new Westside Fire Station, which has been
approved and is expected to break ground in 2018 will be a
significant upgrade in the physical resources available to the
City in terms of hazard preparedness and emergency response.
Table 5.3: Available Resources
Resource Type Background and Capacity Further Information
City of Rohnert Park
Building Code Policy
Document
Provides a guidance and framework for the
construction and maintenance of structures
within the City in conformance with the
International Building Code. Specifically
formulated to mitigate seismic and fire hazards.
http://www.rpcity.org
Zoning Code Policy
Document
Primary tool to serve as the implementing
document of the General Plan. It sets specific
land use regulations and includes the zoning map
for the City. The zoning code is supplemented by
Specific Plans, and also includes a Form Based
Code for Sonoma Mountain Village
http://cityofrohnertpark.hosted.civiclive.com
Figure 5.4: Approved Westside Public Safety Station
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Resource Type Background and Capacity Further Information
General Plan Policy
Document
This is the principal policy document that guides
development and ongoing evolution in Rohnert
Park. The General Plan includes programs and
policies pertaining to land use, housing, and
natural resources. This is the current 8th Edition
of the General Plan that was completed in 2000.
A new General Plan process is expected to start in
early 2018. Hazard data and mitigation activities
described in the LHMP can incorporated in to the
General Plan.
http://www.rpcity.org
Fire Code Policy
Document
The Fire Code of the City of Rohnert Park
provides guidance that complies with the
International Fire Code. The code is recognized
for its ability to mitigate fire hazards.
http://www.rpcity.org
Building Code Policy
Document
Specified how new structures can be built. It
includes the California Building Code in addition
to any amendments made by the City. Mitigation
actions may involve amending the Building Code
to improve a building’s safety or structural
stability.
http://www.rpcity.org
Zoning Code Policy
Document
Is responsible for the practical implementation of
the General Plan. Specifies the physical makeup
of the City. Mitigation actions may involve
amending the Zoning Code to create a safer
community.
http://www.rpcity.org
Emergency
Management
Plan
Policy
Document
The Emergency Management Plan was prepared
in 2012 and outlines the City’s response and
procedures in the event of natural or man-made
hazards.
http://www.rpcity.org
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Resource Type Background and Capacity Further Information
Capital
Improvement
Program (CIP)
Policy
Document
The capital Improvement Program is the City’s
primary method for upgrading and maintaining
critical infrastructure. The CIP is a key vehicle for
implementing actions from the LHMP.
http://www.rpcity.org
Administration Personnel
Resource
Rohnert Park’s administrative unit handles
finance, personnel, and overall
administration/management.
http://www.rpcity.org
Public Safety Personnel
Resource
The department, which combines the functions
of police and fire, conducts emergency
preparedness activities for the community.
Mitigation activities related to emergency
preparedness can be implemented by the
department.
http://www.rpcity.org
Public Works Personnel
Resource
The department is responsible for the
construction and maintenance of the City’s
physical infrastructure.
http://www.rpcity.org
Development
Services
Personnel
Resource
The department, which encompasses planning,
engineering, and building, may be responsible for
mitigation activities related to its functions.
http://www.rpcity.org
Sonoma County
Emergency
Council
County
Resource
Is responsible for the revision and maintenance
of the Sonoma County Emergency Plan. Is also
responsible for the implementation of mutual aid
agreements throughout the county.
http://sonomacounty.ca.gov/Emergency-Council/
Fire Prevention
Division
County
Resource
Is responsible for programs, procedures, and
projects for preventing the outbreak of fires in
the unincorporated areas of the county which
may impact populations, resources, and urban
areas.
http://sonomacounty.ca.gov/FES/Fire-Prevention/
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Resource Type Background and Capacity Further Information
Sonoma
County Water
Agency (SCWA)
Agency
Resource
The SCWA is responsible for maintaining over 75
miles of streams throughout Sonoma County and
provides flood protection for facilities in the
county. The SCWA is also the controlling agency
for the water supply system throughout much of
Sonoma County.
http://www.scwa.ca.gov/
Sonoma
County General
Plan
Policy
Document
The Sonoma County General Plan, like Rohnert
Park’s, is the guiding document for the evolution
of the county.
http://sonomacounty.ca.gov
Sonoma
County Hazard
Mitigation Plan
Policy
Document
The Sonoma County Plan provided general
background information for the development of
the Rohnert Park LHMP.
http://www.sonoma-county.org/prmd/docs/hazard-
mitigation-update/
Santa Rosa
Hazard
Mitigation Plan
Policy
Document
The newly approved Santa Rosa Hazard
Mitigation Plan served as a primary resource and
guide for the development of the Rohnert Park
LHMP.
https://srcity.org/540/Local-Hazard-Mitigation-Plan
SCWA Urban
Water
Management
Plan
Agency
Resource
Is a long-range planning document to aid cities in
Sonoma County to help plan for services and
emergencies through 2035. The plan includes
projections for water demands and supplies.
http://www.scwa.ca.gov/
Sonoma
County Climate
Action Plan
Advisory
Document
The Sonoma County CAP, developed by the
Regional Climate Protection Authority was
developed in coordination with all major
jurisdictions in the County. However, prior to
formal adoption by all jurisdictions, the
document was challenged in court and found to
have been inadequate in its full scope to address
GHG emissions. The document is now merely
advisory but includes many useful policies and
recommendations.
https://rcpa.ca.gov/
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Resource Type Background and Capacity Further Information
SCWA Hazard
Mitigation Plan
Agency
Resource
The Sonoma County Water Agency, similar to the
City of Rohnert Park, must develop and publish a
hazard mitigation plan, to be updated every five
years.
http://www.scwa.ca.gov/
Regional Resources
Association of
Bay Area
Governments
Agency
Resource
Serves as the primary vehicle for Regional
Governance and research particularly in regards
to planning, land use, hazards, and climate
change.
https://www.abag.ca.gov/
Metropolitan
Transportation
Commission
Agency
Resource
Coordinates the planning of major transportation
infrastructure improvements throughout the San
Francisco Bay Area including within Sonoma
County.
http://mtc.ca.gov/
Pacific Gas and
Electric
Technical
Resource
The Pacific Gas and Electric Company (PG&E)
owns the electricity and natural gas transmission
and distribution system in and around Rohnert
Park. It also provides natural gas service and
some electrical service to the community. PG&E
can work with the City to reduce the vulnerability
of energy infrastructure to natural hazards and to
reduce the likelihood of their infrastructure
triggering or exacerbating a hazard.
https://www.pge.com
State and Federal Resources
California
Department of
Transportation
State
Resource
State agency charged with upkeep and
development of California’s roads and bridges.
http>//www.dot.ca.gov/
Office of
Planning and
Research
State
Resource
Constitutes the state planning agency and is
responsible for research and guidance in a
number of different planning areas.
http://www.opr.ca.gov/
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Resource Type Background and Capacity Further Information
California
Office of
Emergency
Services
State
Resource
Cal OES performs its broader mission by
administering numerous programs that support
our stakeholders, protect our communities, and
help create a resilient California.
http://www.caloes.ca.gov/
State Hazard
Mitigation Plan
Policy
Document
State document that provides guidance at a state
level on mitigation actions to reduce the
vulnerability of the state and its citizens from
hazards.
http://www.caloes.ca.gov/for.../hazard-mitigation-
planning/state-hazard-mitigation-plan
National
Weather
Service (NWS)
Federal
Resource
Decision support program that improves
forecasts and interpretations and helps to make
more informed decisions.
http://www.weather.gov/
Federal
Emergency
Management
Agency
Federal
Resource
General guidance for hazard mitigation planning
processes and resources.
https://www.fema.gov/
Cal-Adapt Technical
Resource
This tool provides estimates of future climate
conditions for locations throughout California,
incorporating the expected impacts of climate
change. Cal-Adapt is a resource for understanding
how climate change may affect natural hazards.
http://cal-adapt.org
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Additional Capabilities – WUI Fire Response
Much of the County’s unincorporated area is designated by the State Board of Forestry as “State Responsibility Areas” (SRA).
California Department of Forestry and Fire Protection (CDFFP) provides “primary” wild land fire protection in these areas. While the
SRA designation implies that only CDFFP provides protection for these areas, local fire districts and Community Services Areas
(CSA) also assist with protecting and responding to fires in them. Technically, a fire district/community services area (CSA 40) that
has SRA lands within it is responsible for providing fire protection to structures, and other improvements. In practice, when a wild
land fire occurs in SRA, a mutual aid system is in place that immediately responds CDFFP fire resources as well as local fire
resources.
Redwood Empire Dispatch Communications Authority (REDCOM) is responsible for notifying local fire resources and CDFFP’s
Sonoma/Lake/Napa Emergency Command Center dispatches CDFFP resources.
Ground fire resources are augmented by CDFFP’s helicopter stationed at Boggs Mountain in Lake County and two air tankers based at
the Sonoma Air Attack Base at the Sonoma County Airport. The Sheriff’s Helicopter Unit (Henry One) is equipped with a 150-gallon
water-dropping bucket that can also assist in the effort when other resources are not available.
Sonoma County’s 40 plus fire agencies have signed a countywide mutual aid agreement to insure that firefighting resources and
personnel will be available to combat a wild land/urban interface fire. If these resources are not enough to meet the threat, fire
resources from throughout California can be summoned under the State’s Master Mutual Aid Agreement administered by the
Governor’s Office of Emergency Services.
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PLAN MAINTENANCE AND ADOPTION PROCESS
FEMA Element D: Plan Review, Evaluation and Implementation
• D1. Was the plan revised to reflect changes in development? 44 CFR 201.6(d)(3)
• D2. Was the plan revised to reflect progress in local mitigation efforts? 44 CFR 201.6(d)(3)
• D3. Was the plan revised to reflect changes in priorities? 44 CFR 201.6(d)(3)
FEMA Element E: Plan Adoption
• E1. Does the Plan include documentation that the plan has been formally adopted by the governing body of the jurisdiction
requesting approval? 44 CFR 201.6(c)(5)
It is of crucial importance that this LHMP is up to date, as this will help ensure that Rohnert Park continues to be protected against
hazards and eligible for state and federal mitigation funding. The Plan’s structure allows the City to easily update individual sections
as information becomes available and as needs arise. This will help ensure that the Plan remains current.
Coordinating Group
Maintaining and updating the LHMP is the primary responsibility of the Rohnert Park LHMP Team. The primary departments to
oversee this process are Development Services, Public Safety, and Public Works, under the direction of the LHMP project manager.
The LHMP project manager will function to coordinate the general maintenance of this plan, conduct the formal review process, and
prepare updates to the plan.
Incorporation into Existing Planning Mechanisms
The City has several planning mechanisms:
• General Plan (including Safety Element)
• Specific Plans
• Zoning Ordinance
• Building Code
• Capital Improvements Plan
The City has a Safety Element in its General Plan that includes a discussion of fire, earthquake, flooding, and landslide hazards. In
addition, the City enforces the requirements of the California Environmental Quality Act (CEQA), which, since 1988, requires
mitigation for identified natural hazards. The City has used these pre-existing programs as a basis for identifying gaps that may lead to
disaster vulnerabilities in order to work on ways to address these risks through mitigation.
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The Design Review Committee (DRC) will continue to evaluate ways in which mitigation strategies identified in this planning process
can be incorporated into other projects going on within the City to support risk reduction across a broad range of projects and plans.
Plan Update Process
As required by the Disaster Mitigation Act of 2000, the City of Rohnert Park will update this plan at least once every five years, while
continuously collecting, and analyzing new data by the LHMP Team.
The City of Rohnert Park Planning Department will ensure that monitoring of the LHMP will occur. The plan will be monitored on an
on-going basis. However, any major disasters affecting our City, legal changes, notices from ABAG or Cal OES and other triggers
will be used. Finally, the LHMP will be a discussion item with the meeting of department managers at least once a year in April. At
that meeting, the department heads will focus on evaluating the LHMP in light of technological and political changes during the past
year or other significant events. The department managers will be responsible for determining if the plan should be updated. The
public will continue to be involved whenever the plan is updated and as appropriate during the monitoring and evaluation process.
Prior to adoption of updates, the City will provide the opportunity for the public to comment on the updates. A public notice will be
posted prior to the meeting to announce the comment period and meeting logistics.
Subsequent to this plan’s adoption, a process will kick-off in early 2018 to update priorities, threat analysis, and mitigation
activity sections pertaining to Wildland-Urban Interface fires subsequent to the October 2017 Sonoma County Fire event.
Adoption
The Rohnert Park City Council is the primary group responsible for adopting and updating the plan. Re-adoption should occur every
five years. After the plan has been adopted by the City Council, the Rohnert Park Department of Development Services will be
responsible for transmitting the adopted version to Cal OES and FEMA for their records.
Implementation
The effectiveness of the Plan depends on the implementation of the mitigation actions it contains, including how mitigation actions are
incorporated into existing City plans, policies, and programs. The mitigation actions in the Plan are intended to reduce the loss and
damage from hazard events and to provide a framework for hazard mitigation activities for the City to carry out over the Plan’s
lifetime. The City has prioritized the goals and actions in the Plan, to be implemented through existing mechanisms as the resources to
do so are available. The information in this Plan, including the hazard profiles, the risk and vulnerability analysis, and the mitigation
actions, are based on the best available information, technology, methods, and practices available to the Plan authors as the time this
Plan was prepared.
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Local Hazard Mitigation Plan Points of Contact
Primary Contact:
Name: Zach Tusinger
Title: Planner II
Mailing Address: 130 Avram Avenue
Telephone: (707) 588-2231
Email: ztusinger@rpcity.org
Alternate Point of Contact:
Name: Jeff Beiswenger, AICP
Title: Planning Manager
Mailing Address: 130 Avram Avenue
Telephone: (707) 588-2253
Email: jbeiswenger@rpcity.org
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TECHNICAL APPENDICES AND DOCUMENTS
Appendix A – Acronyms, Abbreviations, and Glossary
Appendix B – Planning Process Documents
Appendix C – Mapping
Appendix D – 2010 ABAG Annex
Appendix E – Supplemental Materials
Appendix F – Plan Review