GP 2025 01 Community Health Safety Element Amendment Sea Level Rise — Point Arena City Council, December 16, 2025

POINT ARENA CITY COUNCIL

AGENDA ITEM SUMMARY
AGENDA ITEM: VIII A
MEETING DATE: 12/16/2025
TITLE
Amendment to General Plan/Local Coastal Program Regarding Sea Level Rise

RECOMMENDED ACTION
Introduce GP# 2025-01 Approving Amendment to the Community Health and Safety Element

ANALYSIS
In 2022, the City of Point Arena applied for and received a $100,000 Local Coastal Program Local Assistance Grant Program Grant funded by the California Coastal Commission. The grant’s purpose was to provide a technical analysis of Arena Cove, develop a policy memorandum, and prepare an amendment to the Community Health and Safety Element (CHSE) of the City’s General Plan/Local Coastal Program.

Following a formal Request for Proposals (RFP) process, the City contracted with Environmental Science Associates (ESA) to conduct the study. ESA has remained a committed partner throughout the extended duration of the project. The primary cause of the delay was the City’s financial constraints in 2024, which limited staff capacity to advance specific projects.

In May 2025, ESA provided the final version of the Sea-Level Rise Analysis and Vulnerability Assessment for Arena Cove (attached) and the accompanying policy memorandum, Sea-Level Rise Policy Recommendations for Updates to the Community Health and Safety Element of the City of Point Arena’s General Plan/Local Coastal Program (attached). Both documents incorporate extensive input from California Coastal Commission staff and are now complete.

The final phase of the grant involves amending the Community Health and Safety Element (CHSE). The proposed modifications have also been reviewed by Coastal Commission staff.

Given the increasing threats to Arena Cove from sea level rise and climate change, the CHSE—last updated in 1995 and currently lacking any discussion of sea level rise— requires revision. The CHSE provides the policy framework for protecting the community from natural hazards and ensuring public safety.

Local Coastal Program (LCP) Amendment No. 2025-01 proposes to update the CHSE to incorporate sea level rise as a key planning consideration. The amendment will provide policy direction for future projects and adaptation efforts in Arena Cove and related coastal areas. Once approved by City Council, the LCP Amendment will need to be submitted to the CCC for their approval, which may include additional suggested modifications. Once agreement and approval have been reached with CCC, then the LCP Amendment would go back to City Council for certification, after which time it would go into effect.

FISCAL IMPACT
Remaining work to be funded by Coastal Commission LCP Local Assistance Grant

ATTACHMENTS

1. Redline Version of CHSE Amendment

2. Sea Level Rise Final Report

3. Technical Memo

4. Public Notice

CITY MANAGER SIGNATURE
_________________________________
Paul Andersen, Assistant City Manager
RESOLUTION NO. 2025-19
RESOLUTION OF THE CITY COUNCIL OF THE CITY OF POINT ARENA ADDING CHAPTER 8.40, SEA LEVEL RISE AND POLICIES TO TITLE 7, COMMUNITY SAFETY AND HEALTH ELEMENT OF THE CITY’S GENERAL PLAN/LOCAL

COASTAL PROGRAM
WHEREAS, California Constitution Article XI, Section 7, enables the City of Point Arena (the “City”) to enact local planning and land use regulations; and
WHEREAS, the authority to adopt and enforce zoning regulations is an exercise of the City’s police power to protect the public health, safety, and welfare; and
WHEREAS, the City adopted a Coastal General Plan (“Coastal GP”) as the Land Use Plan portion of the Local Coastal Program in 1995, which was subsequently amended in 2001 and 2006, and which established policies for all land within Point Arena; and
WHEREAS, the Coastal General Plan includes policies to: (1) advance the orderly growth and development of the City’s Coastal Zone; (2) protect coastal resources; (3) incorporate sustainability into the development process so that Fort Bragg’s coastal resources and amenities are preserved for future generations; (4) respond to current environmental and infrastructure constraints; (5) protect the public health, safety and welfare; and (6) promote fiscally responsible development; and
WHEREAS, the City Council has considered all public comments and a staff report dated November 18, 2025 regarding the proposed ordinance; the staff report is incorporated herein by reference and available for review at City Hall during normal business hours; and
WHEREAS, the proposed minor modification to the Coastal Land Use and Development Code is set forth in its entirety in Section 2 below; and
WHEREAS, the “activities and approvals by a local government necessary for the preparation and adoption of a local coastal program or long-range development plan” pursuant to the California Coastal Act are statutorily exempt from compliance with CEQA, and this statutory exemption “shifts the burden of CEQA compliance from the local agency to the California Coastal Commission (CEQA Guidelines § 15265 (c)).

WHEREAS, the City Council held a duly noticed public hearing on November 18, 2025, to consider the LCP Amendment, accept public testimony; and
NOW, THEREFORE, BE IT RESOLVED that the Point Arena City Council, based on the entirety of the record before it, which includes without limitation, CEQA, Public Resources Code §21000, et seq. and the CEQA Guidelines, 14 California Code of Regulations §15000, et seq.; the Point Arena General Plan; the Point Arena Zoning Code; the Project application; all reports and public testimony submitted as part of the City Council meeting of November 18, 2025 and City Council deliberations; and any other evidence (within the meaning of Public Resources Code §21080(e) and §21082.2), the Point Arena City Council does hereby make the following findings and determinations:

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SECTION 1: LCP AMENDMENT FINDINGS: The City Council hereby finds as follows:

1. The foregoing recitals are true and correct and are made a part of this Ordinance.

2. On November 18, 2025 the City Council held a properly noticed public hearing to consider adoption of the amendment to the General Plan Community Health and Safety Element.

3. The proposed amendment would not be detrimental to the public interest, health, safety, convenience, or welfare of the City and seeks to be consistent with recently adopted State Laws as codified in California Government Code sections 66310 through 66342; and

4. The proposed amendment is internally consistent with other applicable provisions of the General Plan and Zoning Code and the LCP Amendment is consistent with the California Coastal Act.

5. The project is exempt from CEQA, under State CEQA Guidelines § 15265 (c).the “activities and approvals by a local government necessary for the preparation and adoption of a local coastal program or long-range development plan” pursuant to the California Coastal Act are statutorily exempt from compliance with CEQA, and this statutory exemption “shifts the burden of CEQA compliance from the local agency to the California Coastal Commission.

6. Pursuant to Coastal Act Section 30510(a), the City of Point Arena will carry out the Local Coastal Program as amended in a manner fully in conformity with the California Coastal Act; and

7. The documents and other material constituting the record for these proceedings are located at City Hall; and

8. The amendments to the Local Coastal Program shall take effect automatically upon Coastal Commission approval and certification pursuant to Public Resources Code Section 30512, 30513, and 30519.

Based on the foregoing, the City Council hereby adopts the following changes to the City’s Coastal General Plan:

8.40 Sea Level Rise Policies and Programs
Although the bluffs north and south of Arena Cove may also experience increased erosion due to sea-level rise, sealevel rise hazards for development in the City are focused in Arena Cove and Port Road. Sea-level rise will exacerbate hazards including erosion, wave runup and overtopping, and temporary inundation during large storm events from fluvial, coastal, and/or combined flooding, permanent inundation, groundwater rise, which are anticipated to increase in frequency and severity with sea-level rise.

The following policies and programs shall apply:

1. Siting to Protect Coastal Resources and Minimize Hazards: New development shall be sited to avoid hazards, taking into account predicted sea level rise, including groundwater changes, over the anticipated life of the development. Other hazard minimization policies of this chapter shall be read and implemented as requiring the consideration of sea level rise consistent with this section. If hazards cannot be completely avoided, then development shall be sited and designed to protect coastal resources and minimize risks to life and property to the maximum extent feasible for the anticipated life of the development. New development shall assure stability and structural integrity of the development without reliance on shoreline protective devices that

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substantially alter natural landforms along bluffs and cliffs or otherwise harm coastal resources in a manner inconsistent with LCP policies or Coastal Act public access policies, and not contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area.

2. Best Available Science: Planning and development reviews in the City of Point Arena shall use, as applicable, the best available, up-to-date scientific information about projected sea-level rise and other climate change related coastal hazards, including, but not limited to, the City of Point Arena Sea-Level Rise Assessment, CCC’s 2024 Sea Level Rise Policy Guidance, and the State’s 2024 Sea Level Rise Guidance. Coastal hazard mapping, vulnerability assessment, and LCP hazard policies shall be updated as the best available science and guidance (and relevant updates to such documents) becomes available, or as necessary to address significant changes in sea-level rise estimates.

3. Hazard Identification and Mapping: The City’s coastal hazard zones have been mapped using the best available science about projected sea-level rise, erosion, flooding, and other coastal hazards in the City of Point Arena Sea-Level Rise Assessment. Using the coastal hazard maps, site-specific hazard mapping and assessment shall be required for proposed development in the area mapped as “Future Coastal Flood Extent (6.7ft SLR)” and any parcels that contain blufftops as part of the individual development review process. Applications for Coastal Development Permits for development potentially subject to hazards from projected sea level rise, shall include a geologic/flood hazards report prepared by a licensed Geotechnical Engineer that evaluates the potential risk from inundation and/or coastal erosion over the economic life of the development. The report shall evaluate hazards in the context of a 6.7-foot sea level rise (or similarly precautionary sea level rise scenario based on best available science at the time of application) and include recommendations on development location, design, and construction to reduce risk from coastal hazards and avoid impacts to coastal natural resources.

4. Sea-Level Rise Adaptation Plan: The City shall develop and implement a Sea-level Rise Adaptation Plan that builds on the City of Point Arena’s Sea-Level Rise Assessment. The Adaptation Plan will use the best available science to analyze and identify adaptation strategies, timelines, implementation projects, and potential funding sources. The Adaptation Plan shall include community outreach to identify community goals and priorities, consider development of a shoreline and sea-level rise monitoring program, and update emergency response and evacuation procedures, as consistent with other sections of the General Plan. The findings of the Adaptation Plan will be incorporated into the City’s LCP as appropriate.

The City shall reassess its Sea-level Rise Adaptation Plan (and any commensurate LCP amendments) every ten years at minimum. The reassessment shall consider the following:
• Efficacy of Adaptation Plan and implemented measures. • Updated sea-level rise projections and risks, using best available science. • Potential need to revise adaptation measures or implement new measures, including review of emerging engineering, science, and technologies.
• Funding needs and potential funding sources.
• Meaningful involvement of the public and environmental justice communities, including community-based organizations, in future adaptation planning.
• Minimization of barriers to public coastal access or consideration of the public access needs of environmental justice communities.

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5. Critical Infrastructure: The City will pursue opportunities to preserve, protect and/or adapt as appropriate critical local infrastructure to protect public safety and mitigate against economic loss and reductions in coastal access.

6. Assumption of Risk: As a condition of coastal permit approval for new development in an marea subject to current or future hazards, applicants shall be required to acknowledge and agree that the development is located in a hazardous area or an area that may become hazardous in the future. The applicant shall also acknowledge that sea level rise could render it difficult or impossible to provide services to the site; that new development waives any right to construct shoreline protective devices; that the boundary between public tidelands and private land may shift with rising seas and the development approval does not permit encroachment onto public trust land; that removal or additional adaptation strategies may be required in the future to address sea level rise consistent with the Coastal Act and the certified LCP; and that the applicant waives any future claims of damage or liability against the permitting agency and agrees to indemnify the permitting agency against any liability, claims, damages or expenses arising from any injury or damage due to such hazards.

NOW, THEREFORE, BE IT RESOLVED, that the City Council of the City of Point Arena approved Resolution 2025-xx to add Section 8.40 Sea Level Rise CHAPTER 8.40, SEA LEVEL RISE AND POLICIES TO TITLE 7, COMMUNITY SAFETY AND HEALTH ELEMENT OF THE CITY’S GENERAL PLAN/LOCAL COASTAL PROGRAM PASSED AND ADOPTED The foregoing Resolution No. 2024-19 was passed and adopted at a regular meeting of the Point Arena City Council on the 18th day of November 2024 by the following vote: Motion by _______, Seconded by ________.

Ayes:

Noes:

Absent:

Abstain:

Mayor
ATTEST:

Paul Andersen
City Clerk
VII. Health & Safety, Page 1
VII. COMMUNITY HEALTH AND SAFETY ELEMENT

1. INTRODUCTION
This chapter covers safety, as prescribed by Safety Element provisions of the California Government Code, Section 65302(g); air quality; and water supply and quality, which are parts of the State-mandated Conservation Element, Section 35602(d) but are included as part of this element rather than as a part of the conservation element.

The underlying assumption of this element is that the City can reduce the hazards caused by certain natural occurrences if the probabilities of such conditions are known in advance and plans for dealing with them are prepared.

State law requires that the Safety Element address the protection of the community from unreasonable risks associated with the effects of seismically-induced surface rupture, ground shaking, ground failure, tsunami and seiche; slope instability due to mudslides and landslides; subsidence and other known geologic hazards; flooding; and wildland and urban fires.

State law requires that local communities also adopt measurable noise standards as well as programs that will ensure that they are adhered to. These are to be found in the separate Noise Element of this general plan.

After setting forth public health and safety goals, the implementing policies and programs of this element are presented. They are divided into eight sections: seismic safety; flood hazards and control; slope stability; fire protection; air quality; water supply and quality; waste water collection and treatment; emergency preparedness; and hazardous materials transportation and storage.

2. COMMUNITY SAFETY GOALS

1. Strive to protect the community from injury, loss of life, and property damage resulting from natural catastrophes and hazardous conditions.

2. Strive to reduce the impact of pollutants on the well-being of Point Arena citizens, and on plants and wildlife.

3. Provide an adequate, consistent, and safe supply of water to meet Point Arena's domestic, commercial and fire fighting needs, and protect the city's ground water from pollutants.

4. Recognize the importance of the Garcia River and of the Garcia River Watershed and ecosystem to the City's well being.

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5. Ensure that the city and its citizens, and businesses, are prepared for an effective response to major emergencies.

3. COMMUNITY SAFETY POLICIES AND PROGRAMS
The following are the City's policies and programs with respect to community health and safety, by category of concern:

1. New development shall: (a) Minimize risks to life and property in areas of high geologic, flood, and fire hazard. (b) Assure stability and structural integrity, and neither create nor contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area or in any way require the construction of protective devices that would substantially alter natural landforms along bluffs and cliffs. (c) Be consistent with requirements imposed by an air pollution control district or the State Air Resources Control Board as to each particular development.

2. All proposed land divisions, including lot line adjustments, shall be prohibited unless potential future development on all proposed parcels can be demonstrated to be safe from flooding, erosion, and geologic hazards and will be provided with a safe, legal, all-weather access road(s), which can be constructed consistent with all policies of the LCP.

3.1. Seismic Safety Policies and Programs
Seismic hazards originate from sources both inside and outside of the city's corporate boundaries and pose both direct (primary) and indirect (secondary) risks to inhabitants. Primary hazard risks are land surface ruptures along a fault trace during an earthquake of moderate to major magnitude. Such an occurrence would pose a hazard to structures, utilities, and roads which traverse or straddle the fault.

Although Hathaway Creek Fault is not a major one it does traverse part of the city and may be a source of a primary risk. It is likely any seismic activity on this fault would be associated with major seismic activity on the San Andreas Fault north of the city.

Secondary seismic risks include ground shaking, lurch cracking of soil surfaces, liquefaction of soils, and lateral spreading, and may occur on unstable soils, of which there are those (Santa Lucia) shown on the Opportunities and Constraints Map of this general plan. Another secondary risk is a tsunami tidal wave action.

The following policies and programs shall apply:

1. The City shall undertake studies that establish acceptable levels of risk/safety standards, and shall cause existing buildings to be brought up to those standards.

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2. The City shall require dynamic ground-motion analyses and responsive structural design for all new privately owned, high-occupancy structures (e.g., theaters, apartment houses, places of public assembly) and for structures for whose continued function in the event of a seismic disaster is critical (for example, public assembly buildings), and have plan checks for these buildings performed by a licensed structural engineer. The City shall also continue to invoke Sections 5.20 and 5.21 of the Zoning Ordinance in connection with all new proposed developments.

3. The City shall avoid placement of critical facilities and habitable structures in areas prone to ground failure during an earthquake or within areas subject to Tsunami wave run-up.

4. The City shall prepare a more detailed Seismic Safety sub- element that translates general plan seismic safety policies into specific programs, mitigation measures, and specifications... largely with respect to potentially seismically-hazardous buildings constructed prior to enactment of codes requiring earthquake-resistant design. The sub-element shall be submitted to the Coastal Commission as an LCP amendment for certification.

5. The City shall determine the precise location and map the Hathaway Creek Fault as generally shown on the “Natural Hazards” Opportunities and Constraints Map of the General Plan. The City shall require site-specific qualifying engineering studies for all new construction within any fault zone. The map shall be submitted to the Coastal Commission as an LCP amendment for certification.

6. The City shall review local- and distant-source tsunami inundation maps for Point Arena and adjacent coastal communities as they are developed to identify susceptible areas, plan evacuation routes or location suitable for vertical evacuation and make evacuation plans available to all emergency responders and other appropriate parties.

7. The City shall identify and map potential tsunami inundation zones for land use planning.

Maps should identify generalized tsunami inundation zones on a probabilistic basis (e.g., 100- year event). These maps shall be submitted to the Coastal Commission for certification.

8. The City shall periodically review and update tsunami preparation response policies/practices to reflect current inundation maps and design standards, and submit these updated policies to the Coastal Commission for certification.

9. If new development is proposed within a potential tsunami inundation zone as identified by policy nos. 6 and 7, the City shall require a site-specific hazard analysis for a 100-year tsunami event. Where feasible, development shall be sited outside of the area identified as a tsunami inundation zone in the site specific wave run-up analysis.

10. If it is not feasible to site new development outside of tsunami inundation zones identified by the site-specific analysis required in policy no. 8, development shall be located and designed to minimize tsunami losses and damage.

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11. The City shall avoid where feasible siting new critical facilities, including fire and police stations and hospitals in tsunami inundation zones. If it is necessary to site such facilities in tsunami inundation zones to provide adequate population protection, new critical facilities shall be located and configured to be functional immediately after a 100-year tsunami event.

12. The City shall develop a local response plan and/or participate in any regional effort to develop and implement workable response plans for distribution of information on tsunami alerts, watches, and warnings, to appropriate emergency responders and City personnel.

13. The City shall include tsunami evacuation route information as part of any overall evacuation route sign program implemented in the City. Evacuation routes should be clearly posted. An evacuation route traffic monitoring system that provides real-time information on the traffic flow at critical roadways should be considered.

14. The City shall develop and implement a tsunami educational program for residents, visitors, and people who work in the susceptible areas. 15. The City shall require that overnight visitorserving facilities in susceptible areas to provide tsunami information and evacuation plans.

3.2. Flood Hazard Policies and Programs
Flood hazards in the city are limited to the area along Arena Creek and to the present parking area at Arena Cove. The latter is a result of heavy seas during winter storms, and the former a function of both heavy seas and heavy runoff along Arena Creek. At times the creek may run high and partially inundate properties located at various points along its length.

The following policies and programs shall apply:

1. The City shall maintain an updated flood control plan. It should address issues such as (a) natural flooding resulting from major rain storms that cause overflows of Arena Creek and may be aggravated by the City's inadequate storm drainage facilities, (b) mud and debris flows that may originate in hill areas having deep top soils with poor drainage characteristics, and (c) improvements in drainage systems sufficient to handle increases in storm drainage capacity as development increases.

2. Buildings within flood prone areas subject to inundation or erosion shall be prohibited unless no alternative building site exists on the property and proper mitigation measures are provided to minimize or eliminate risks to life and property from flood hazard.

3. The City shall establish standards to mitigate downstream impacts associated with new development.

4. Drainage channels shall be improved or maintained so as to preserve the natural character of waterways.

5. The City shall continue to be guided by the Federal Emergency Management Agency VII. Health & Safety, Page 5
(FEMA) and/or the Federal Insurance Administration with respect to "special flood hazards" identified in the scientific and engineering report entitled "Flood Insurance Study for Point Arena" dated June 3, 1986 together with the accompanying "Flood Insurance Rate Map".

6. No structure on land shall be located, constructed, extended, converted, or altered without full compliance with the terms of the City's Flood Damage Prevention Ordinance (Ordinance # 126) and without first obtaining a development permit as per Section 4.1 of said ordinance.

3.3. Slope Stability Policies and Programs
Soils hazards are largely limited to engineering constraints posed to urban development given the city's Santa Lucia soils. Slopes which exceed 20% in grade clearly must be acknowledged as constraints on development. Poor bearing capacity and surface and subsurface soil materials pose the greatest risk of soil failure, particularly when water-saturated. Within Point Arena such slopes in excess of nine percent may be unstable.

Considerable hazard to public safety is apparent with regard to coastal bluffs and their uses, and the potential for sea-cliff retreat is significant, posing a considerable hazard for development occurring along the vacant coastal bluffs. Open space and agricultural uses are appropriate with very-low residential uses allowed only subject to site specific and qualified geologic and soils studies. Areas south of Arena Cove are especially vulnerable.

In addition, landslides are most likely in hillside locations under conditions where (a) rock strata parallels surface slopes; (b) high clay content absorbs excess water; (c) displacement has fractured a fault zone; or (d), the bases of slopes have been removed by erosion or by people.

Landslides can be triggered by heavy rains, human actions, or earthquakes.

The following policies and programs apply:

1. Applications for new development, where applicable and as required in the Sections 5.20 and

5.21 of the City’s ordinance, shall include a geologic/soils/geotechnical study that identifies any geologic hazards affecting the proposed project site, any necessary mitigation measures, and contains a statement that the project site is suitable for the proposed development and that the development will be safe from geologic hazard. Such reports shall be conducted by a licensed Certified Engineering Geologist (CEG) or Geotechnical Engineer (GE). Both on-site and off-site hazardous impacts shall be considered.

2. Development shall not be permitted until necessary mitigation measures are implemented to limit potential damage to levels of acceptable risk.

3. The City shall encourage clustering of developments away from areas unsuitable for development because of slope instability problems.

4. Replanting of non-invasive vegetation following development shall be required on slopes prone to instability, and drought-resistive non-invasive plants shall be used for landscaping VII. Health & Safety, Page 6
slopes where excessive watering might induce landslides or erosion.

5. On ancient landslides, unstable slopes and other geologic hazard areas, new development shall only be permitted where an adequate factor of safety can be provided, consistent with the applicable provisions of Section 5.21 of the City’s zoning ordinance.

6. The remediation or stabilization of landslides that affect existing structures or that threatens public health or safety may be permitted. Alternative remediation or stabilization techniques shall be analyzed to determine the least environmentally damaging alternative. Maximum feasible mitigation shall be incorporated into the project in order to minimize adverse impacts to resources.

7. Grading and/or development-related vegetation clearance shall be prohibited where the slope exceeds 40 percent (2.5:1), except that driveways and/or utilities may be located on such slopes, where there is no less environmentally damaging feasible alternative means of providing access to a building site, provided that the building site is determined to be the preferred alternative and consistent with all other policies of the LCP.

8. New development shall provide adequate drainage and erosion control facilities that convey site drainage in a non-erosive manner in order to minimize hazards resulting from increased runoff, erosion and other hydrologic impacts to streams.

8.5 New development shall: (1) avoid creating concentrated runoff, particularly over steep slopes and bluff faces, by installing energy dissipating devices, (2) create drainage swales, detention, and retention basins, (3) control the timing and manner of new construction so that there are no bare soil slopes during the rainy season.

9. All swimming pools proposed near coastal bluffs and within 100 feet of fault zones shall contain double wall construction with drains and leak detection systems.

10. New development on or along the shoreline or a coastal bluff requiring on-site waste disposal systems shall site systems as far landward as possible in order to avoid the need for protective devices to the maximum extent feasible.

11. New development in the cove or on an oceanfront bluff shall be sited outside areas subject to inundation or wave up-rush at any time during the full projected 75-year economic life of the development. If complete avoidance of hazard areas is not feasible, all new cove or oceanfront bluff development shall be elevated above the base Flood Elevation (as defined by FEMA) and setback as far landward as possible. All development shall be setback a minimum of 10 feet landward of the most landward surveyed mean high tide line. Whichever setback method is most restrictive shall apply. Development plans shall consider hazards currently affecting the property as well as hazards that can be anticipated over the life of the structure.

12. All new development located on a bluff top shall be setback from the bluff edge a sufficient distance to ensure that it will be stable for a projected 75- year economic life. Stability shall be VII. Health & Safety, Page 7
defined as maintaining a minimum factor of safety against sliding of 1.5. This requirement shall apply to the principle structure and accessory or ancillary structures. Ancillary structures such as decks, patios and walkways that do not require structural foundations may extend into the setback area to a minimum distance of 15 feet from the bluff edge. Ancillary structures shall be removed or relocated landward when threatened by erosion. Slope stability analyses and erosion rate estimates shall be performed by a licensed Certified Engineering Geologist or Geotechnical Engineer.

13. All new ocean-front and bluff top development shall be sized, sited and designed to minimize risk from wave run-up, flooding and beach and bluff erosion hazards without requiring a shoreline protection structure at any time during the life of the development.

14. As a condition of approval of new development on a vacant ocean-front or bluff top lot, or where demolition and rebuilding is proposed, where geologic or engineering evaluations conclude that the development can be sited and designed to not require a shoreline protection structure as part of the proposed development or at any time during the life of the development, the property owner shall be required to record a deed restriction against the property that ensures that no shoreline protection structure shall be proposed or constructed to protect the development approved and which expressly waives any future right to construct such devices that may exist pursuant to Public Resources Code Section 30235.

15. No permanent structures shall be permitted on a bluff face, except for engineered stairways or accessways to provide public beach access. Such structures shall be constructed and designed to not contribute to further erosion of the bluff face and to be visually compatible with the surrounding area to the maximum extent feasible.

16. Existing shoreline protection structures which do not conform to the provisions of the LCP may be repaired and maintained to the extent that such repairs and/or maintenance conform to the provisions of Title 14 CCR Section 13252 and Section 6.11(B)(5) of the Zoning Ordinance.

17. Land divisions, including subdivisions, lot splits, lot line adjustments, and certificates of compliance which create new shoreline or bluff top lots, shall not be permitted unless the subdivision can be shown to create lots which can be developed without requiring a current or future bluff or shoreline protection structure. No new lots shall be created that could require shoreline protection or bluff stabilization structures at any time during the full 75-year life of the development.

18. Siting and design of new shoreline development and shoreline protective devices shall take into account anticipated future changes in sea level. In particular, an acceleration of the historic rate of sea level rise shall be considered. Development shall be set back a sufficient distance landward and elevated to a sufficient foundation height to eliminate or minimize to the maximum extent feasible hazards associated with anticipated sea level rise over the expected 75- year economic life of the structure.

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3.4. Fire Protection Policies and Programs
Fire hazards in Point Arena are either site-specific or generalized. In the case of site-specific fires, the local volunteer fire department is capable of responding adequately, and the combination of personnel, infrastructure (hydrants) and equipment is adequate to yield a rating of "8" or "9" on the general fire insurance rate schedule.

The most significant risk of fire in town is to the Downtown area where there are a number of older buildings and relatively high building densities. On a more generalized level the California Department of Forestry rates the area as having a "moderate" rating on the Fire Hazard Severity Scale during the peak summer season. This is because of the usually higher humidity levels and low fuel vegetation components of coastal terrace lands.

A major problem for the city is the absence of an alternative emergency route to and from Arena Cove. The lack of a secondary route is addressed in the Traffic and Circulation element of this general plan.

The following policies and programs apply:

1. Potential fire hazards, including existing fire-vulnerable buildings, shall be mitigated where appropriate, through proper fire-protection methods and fire-fighting practices, by clearing vacant land of excessive vegetation, and by updating fire- protection regulations for new construction and remodeled buildings.

2. The City shall strive to assure a five-minute response time for emergency vehicles, and to improve the ISO rating to "7" overall.

3. An adequate and safe supply of water to meet fire fighting needs shall be ensured. The City shall allow new development only in areas where adequate water pressure for fire suppression is available.

4. The City shall establish a program to upgrade fire fighting vehicles, equipment and storage facilities.

5. The City should consider establishing a fire control assessment district and/or a focused development impact fee policy and schedule to carry out its upgrade program.

6. Woodstoves and fireplaces in buildings with common walls should be prohibited or potential risks satisfactorily mitigated.

7. The City should ensure that all new wood stove installations or replacements meet prevailing and current State requirements.

8. Roads and streets shall be designed and constructed to satisfy up-to-date Fire Safety Regulations of the State Board of Forestry, where applicable.

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9. The City should require maintenance of a 500-gallon per minute fire flow standard in all existing and future city fire hydrants, with higher pressure standards to apply in higher density and industrial areas.

10. The City should require all new building and remodeling plans to be in conformance with applicable building and fire code standards. Prior to commencement of grading or construction, plans shall be submitted for approval to the City of Point Arena.

11. The City shall evaluate the feasibility of expanding the existing fire station or a acquiring a new fire station that would facilitate the housing of additional fire-fighting equipment and personnel.

12. When brush clearance is required for fire safety, brushing techniques that minimize impacts to native vegetation, ESHA and that minimize erosion, runoff, and sedimentation shall be utilized.

13. Applications for new development, which require fuel modification, shall include a fuel modification plan for the project, prepared by a landscape architect or resource specialist that incorporates measures to minimize removal of native vegetation and to minimize impacts to ESHA, while providing for fire safety, consistent with the requirements of the applicable fire safety regulations. Such plans shall be reviewed and approved by the Forestry Division.

3.5. Police Protection Policies and Programs
The City should maintain and periodically renegotiate contractual arrangements with the Mendocino County Sheriff's Department to ensure that a satisfactory level of traffic enforcement and general law enforcement is provided to the City, its residents, and visitors.

The City should work to provide a sufficient level of police service to maintain a minimum 20- minute response time to emergency calls.

3.6 Sea-Level Rise Policies and Programs
Although the bluffs north and south of Arena Cove may also experience increased erosion due to sea-level rise, sea-level rise hazards for development in the City are focused in Arena Cove and Port Road. Sea-level rise will exacerbate hazards including erosion, wave runup and overtopping, and temporary inundation during large storm events from fluvial, coastal, and/or combined flooding, permanent inundation, groundwater rise, which are anticipated to increase in frequency and severity with sea-level rise.

The following policies and programs shall apply:

1. Siting to Protect Coastal Resources and Minimize Hazards: New development shall be sited to avoid hazards, taking into account predicted sea level rise, including groundwater changes, over the anticipated life of the development. Other hazard minimization policies of this VII. Health & Safety, Page 10
chapter shall be read and implemented as requiring the consideration of sea level rise consistent with this section. If hazards cannot be completely avoided, then development shall be sited and designed to protect coastal resources and minimize risks to life and property to the maximum extent feasible for the anticipated life of the development. New development shall assure stability and structural integrity of the development without reliance on shoreline protective devices that substantially alter natural landforms along bluffs and cliffs or otherwise harm coastal resources in a manner inconsistent with LCP policies or Coastal Act public access policies, and not contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area.

2. Best Available Science: Planning and development reviews in the City of Point Arena shall use, as applicable, the best available, up-to-date scientific information about projected sealevel rise and other climate change related coastal hazards, including, but not limited to, the City of Point Arena Sea-Level Rise Assessment, CCC’s 2024 Sea Level Rise Policy Guidance, and the State’s 2024 Sea Level Rise Guidance. Coastal hazard mapping, vulnerability assessment, and LCP hazard policies shall be updated as the best available science and guidance (and relevant updates to such documents) becomes available, or as necessary to address significant changes in sea-level rise estimates.

Applications for Coastal Development Permits for development potentially subject to hazards from projected sea level rise, shall include a geologic/flood hazards report prepared by a licensed Geotechnical Engineer that evaluates the potential risk from inundation and/or coastal erosion over the economic life of the development. The report shall evaluate hazards in the context of a 6.7-foot sea level rise (or similarly precautionary sea level rise scenario based on best available science at the time of application) and include recommendations on development location, design, and construction to reduce risk from coastal hazards and avoid impacts to coastal natural resources.

The findings of the Adaptation Plan will be incorporated into the City’s LCP as appropriate.

The City shall reassess its Sea-level Rise Adaptation Plan (and any commensurate LCP amendments) every ten years at minimum. The reassessment shall consider the following:

VII. Health & Safety, Page 11
• Efficacy of Adaptation Plan and implemented measures. • Updated sea-level rise projections and risks, using best available science. • Potential need to revise adaptation measures or implement new measures, including review of emerging engineering, science, and technologies. • Funding needs and potential funding sources.
• Meaningful involvement of the public and environmental justice communities, including community-based organizations, in future adaptation planning. • Minimization of barriers to public coastal access or consideration of the public access needs of environmental justice communities.

6. Assumption of Risk: As a condition of coastal permit approval for new development in an area subject to current or future hazards, applicants shall be required to acknowledge and agree that the development is located in a hazardous area or an area that may become hazardous in the future. The applicant shall also acknowledge that sea level rise could render it difficult or impossible to provide services to the site; that new development waives any right to construct shoreline protective devices; that the boundary between public tidelands and private land may shift with rising seas and the development approval does not permit encroachment onto public trust land; that removal or additional adaptation strategies may be required in the future to address sea level rise consistent with the Coastal Act and the certified LCP; and that the applicant waives any future claims of damage or liability against the permitting agency and agrees to indemnify the permitting agency against any liability, claims, damages or expenses arising from any injury or damage due to such hazards.

4. AIR QUALITY POLICIES AND PROGRAMS
Point Arena is in a unique location with respect to air quality because of its proximity to the ocean and the pathway of prevailing winds. One exception is the Mill Street corridor where woodstove smoke often lingers and becomes bothersome and may prove unhealthy to some.

The Point Arena area is located in the North Coast Air Basin, and the Mendocino County Air Pollution Control District (MCAPCD) is the regional agency with the responsibility for enforcing State of California Ambient Air Quality Standards (CAAQSA) and the National Ambient Air Quality Standards.

Sources of air pollution within the area are divided into stationary sources and mobile sources, the latter mostly along Highway 1. The former consist of fireplaces and wood stoves, and VII. Health & Safety, Page 12
activities at the industrial site on Riverside Drive. Residential fuel burning on days with a marine inversion layer leads to local accumulations in low-lying areas, mostly along Mill Street.

To maintain Point Arena's high air quality and to reduce significant impacts caused by growth and development to less- than-significant levels, the following policies shall apply:

1. Development which would result in the violation of any State ambient air quality standard or generate a significant amount of air pollutants will not be permitted.

2. The City shall ensure that all new wood stove installations or replacements meet clean air standards (EPA Phase 2 requirements), except that wood stoves and fireplaces in high- density low inversion residential areas may not be approved if the effect is to contribute to a reduction of air quality.

3. The City will prohibit the burning of non-vegetative materials, garbage, clothes, plastics, and construction or demolition wastes.

4. The City will require that new and upgraded/modified industrial and commercial developments utilize BMP (Best Management Practices) for pollution control.

5. To mitigate local and regional impacts due to dust and emissions from construction activities, and to prevent fugitive dust from being transported off-site, a "construction dust control policy" should be adopted and implemented. The following measures shall be considered when adopting a construction dust policy:
a. Areas of soil redistribution shall be watered down twice daily or as necessary to trap fugitive dust and particulate during construction until plants, grass growth, or building coverage reduce the need for such measures.
b. If water is limited, soil binders such as soil cement may be spread in conjunction with watering, or sheet coverings such as burlap may be used on small areas. Areas with soil binders shall be turned over prior to re-vegetation.
c. During periods of excessive wind speeds, construction shall be temporarily suspended. d. Disturbed areas shall be re-vegetated or paved as soon as possible to reduce dust during construction activities.

5. AIR QUALITY POLICIES AND PROGRAMS, PER THE COUNTY OF

MENDOCINO AIR QUALITY MANAGEMENT DISTRICT

1. The City shall require all air quality mitigation measures to be reasonable, effective, feasible, measurable, and implementable concurrent with project development.

VII. Health & Safety, Page 13
Implementation Strategy: Consult with the Air Quality Management District regarding the effectiveness of mitigation measures proposed by the applicant. When using mitigation measures suggested by the Air Quality Management District, consider sitespecific factors, which may make a measure infeasible. Consider measures to reduce traffic in other parts of the community to offset emissions (or traffic) not mitigated by site-specific measures.

2. In the short-term planning period, the City shall support the development and use of Air Quality Impact Assessment Guidelines that will provide: A) standard criteria for determining significant environmental effects, B) a uniform method of calculating project emissions, C) a list of standard mitigation measures.

Implementation Strategy: Work with the Air Quality Management District and other planning agencies to develop and implement standards that are uniform throughout the county. The Air Quality Management District will act as primary author of the Air Impact Quality Assessment Guidelines. The District will hold workshops and meetings to gather ideas from citizens and affected agencies, with a completed product ready within three years.

3. The City shall consult with the Air Quality Management District during CEQA review for all discretionary projects. The City shall consult with the Air Quality Management District prior to accepting applications for development projects meeting or exceeding Air Quality Management District emissions thresholds, and other projects as appropriate.

Implementation Strategy: Conduct a pre-application air quality review to identify issues or problems that might require re-design or major alterations of the project. The District may also review formal air quality impact analyses submitted by the applicant for adequacy. This will ensure that the environmental document bases its conclusions on accurate information.

4. The City shall request Caltrans and other transportation agencies to construct or improve facilities for all travel modes on Highway 1.

Implementation Strategy 1: Identify the location of all bicycle, pedestrian, and transit facilities on General Plan maps, and consider developing additional signage to help residents and visitors use these routes. Request Caltrans to help fill gaps in needed facilities.

Implementation Strategy 2: Work with Mendocino Council of Governments and other agencies to pursue funding for alternative transportation facilities under STA (d1), TDA, federal TEA, state bike lane account, and other sources.

5. The City shall support and participate in the air quality education programs of the Air Quality Management District.

VII. Health & Safety, Page 14
Implementation Strategy 1: The City shall assist the Air Quality Management District in educating developers and the public on the benefits of pedestrian and transit friendly development. A key tool will be joint participation by City staff and council members in District seminars on planning for air quality and other community values.

Implementation Strategy 2: During the short term planning period, the City shall develop community education programs about the possibilities of reducing air pollution through personal life-style choices. This program would include the importance of using wood burning appliances appropriately, alternatives to open-burning such as chipping and composting, and use of alternative transportation.

6. The City shall support agricultural education programs that increase the awareness among farmers of techniques to reduce PM-10 emissions.

Implementation Strategy: During the short-term planning period, work with the Farm Bureau, the University of California, the Air Quality Management District and farm organizations on educational programs.

7. The City shall require measures to reduce particulate emissions from road and site construction, grading, and demolition to the maximum extent feasible. Developers must cover all access roads, driveways, and parking areas with pavement or other appropriate material serving new commercial and industrial development.

Implementation Strategy: Utilize recommendations from the Air Quality Management District on appropriate dust-control activities, suitable for soil, wind, slope, and other site particulars. Provide for regular inspection of the projects' dust-suppression measures.

Incorporate dust-control enforcement provisions in all construction permits, and consult with District enforcement staff if a nuisance issue arises from project earth-moving or construction-equipment exhaust. Include paving requirements as part of the development standards of the Zoning Ordinance.

8. In consultation with the Air Quality Management District, the City shall develop a program to reduce PM-10 emissions from City and County maintained roads within the planning area.

Implementation Strategy 1: Inventory unpaved roads (private and public) within the planning area. Conduct regular traffic counts (ADT) on these roads during dry months (May through October). Require application of dust palliatives when traffic levels exceed 300 ADT during this period. During drought periods, monitor traffic and dust levels as appropriate. Over the intermediate planning period, develop plans and funding sources to pave heavily-used dirt roads.

Implementation Strategy 2: Maintain a street sweeping program throughout the planning area. Landscape shoulders and medians. Consider lowering speed limits on roads which cannot be paved during the short-term period, and implementing traffic calming measures VII. Health & Safety, Page 15
to keep speeds low.

9. The City shall work with Caltrans, Mendocino Council of Governments, and other local agencies or institutions to develop programs that reduce the impact of automobile commuting.

Implementation Strategy 1: During the short-term planning period, request Caltrans and MCOG to identify suitable sites for park-and-ride lots within the planning area.

Designate these sites within the Circulation Element.

Implementation Strategy 2: Encourage Banks, Savings and Loans, and other lending institutions to consider commute distances and associated travel costs when reviewing mortgage applications. This review should encourage people to live and work in the same community whenever possible.

Implementation Strategy 3: The City should construct appropriate park-and-ride lots on public land or other available areas as needed. The City (or County) may require new projects to construct park-and-ride lots as traffic and air quality mitigation.

Implementation Strategy 4: Utilize park-and-ride lot construction as an offset for new project traffic-created air pollution. Incorporate park-and-ride lot construction in standard CEQA mitigation measures for developments expected to generate over 500 ADT. Coordinate with MTA and major employers to establish express buses and vanpools to increase patronage of park-and-ride lots.

10. The City shall, through the development process, reduce air quality impacts resulting from space heating. The City shall require primary heat sources in all new development, room additions, or remodels involving space heating to utilize solar, pellet stoves, propane, butane, fuel oil, vented kerosene heaters or electricity. The City may restrict or prohibit installation of wood burning appliances in new development, especially in multi-family rental units.

Implementation Strategy 1: Commencing within 180 days of Plan adoption, City plan reviews and inspections should verify that solar access is optimized and primary heat sources come from low-polluting sources (cited above). Secondary heat should come only from EPA certified wood stoves, or fireplace inserts.

Implementation Strategy 2: Where wood stoves or fireplace inserts are permitted, (a) dwellings should incorporate increased insulation or reduced window area sufficient to exceed insulation requirements of Title 24 of the state energy code by 25% or more.

Implementation Strategy 3: Pursuant to Strategy 2 above, all new wood stoves, fireplaces, and fireplace inserts must pay an offset fee of $700 at the time of permitting.

This fee will be used to replace existing non-certified wood-burning devices used for primary heat sources with butane, propane or other very clean heaters. Increased insulation or weatherization of low-income family homes may be part of the replacement VII. Health & Safety, Page 16
process. The City may request the Air Quality Management District to provide assistance in administering the replacement program.

11. Little air monitoring is available for the coastal area near Point Arena. Conducting regular monitoring of Respirable Particulate Matter (PM10) and other ambient air pollutants such as ozone will help ensure that air quality remains good, and provide immediate notice if unhealthful conditions occur.

Implementation Strategy: Support establishment of a monitoring station for PM10 or other ambient air pollutants. The City can assist the Air Quality Management District to locate a suitable site for monitoring equipment and might provide electric power or other services.

6. WATER SUPPLY AND WATER QUALITY POLICIES AND PROGRAMS The Point Arena Water Works, a privately-owned utility under California Public Utility Commission oversight, supplies water to most of Point Arena. The exceptions are users who have individual wells. The major source of water is a well adjacent to the Garcia River. The main storage tank is just east of Downtown. It is estimated that the present system produces 33,000 gallons per day and delivers water to approximately 179 homes and businesses.

Existing water permits allow the Point Arena Water Works to pump 0.22 cubic feet per second (142,000 gallons per day) or a maximum of 100 acre feet per year (90,000 gallons per day).

Existing water storage is capable of holding 575,000 gallons.

Under the current water permits, a maximum of 1,385 people may be served (90,000 gallons per day maximum at 65 gallons per person).

A new water line has been installed at the north end of town by the Point Arena Water Works (Permit 03-93) rendering more-than- adequate water pressure to the northern sections of the City.

Lacking is an emergency contingency plan in the advent of loss of water at its source or within the system due to a natural disaster, particularly seismic activity at the river or seismic activity in the vicinity of any water lines or storage tanks.

Water quality is regulated by the State Department of Health Services, which agency conducts regular inspections to ensure continuing water quality.

A. The following policies governing the supply and delivery of water shall apply:

1. The City will continue to work with the PAWW ownership to ensure that maintenance of the Garcia River's water quality and water supply for domestic purposes is guaranteed and meets State standards for operation and testing.

2. The city and PAWW will maintain an updated water service plan to incorporate the changing VII. Health & Safety, Page 17
needs of the city, and to consider the impacts of drought or peak fire-fighting demand.

3. Care shall be taken to ensure that the quality of the city's ground water supply is maintained.

This can be assured by limiting or prohibiting private septic tanks.

4. The City shall consider, as a long-range possibility, the merits of purchasing, operating and maintaining the existing water supply system. In the interim, the City should complete or cause to be completed a satisfactory capacity study of the current water system, to include data on system capacity (pumps, filters, storage capacity, delivery system) and source capacity. Included should be studies of the capacity of the Garcia River in drought-year conditions.

5. Extension of the water system and new hookups should be permitted within the urban limit line, and hookups of new developments on lots smaller than one acre shall be required.

6. The City should monitor land-use activities and development projects within the Garcia River watershed and oppose those activities and projects that may have an adverse effect on the city's water supply or quality.

7. The State Board of Forestry should be asked to notify the City of any timber harvesting plans submitted within the watershed, with full consideration to be given to possible impacts on the watershed of practices that might increase turbidity, runoff, and debris.

8. Due to the proximity of the water system's Garcia River well to a known fault zone, the City shall assess the seismic risk the fault poses to the well, pumps, and the eight inch main which extends from the water source to the city, and shall develop an emergency contingency plan in cooperation with the County of Mendocino.

9. The City shall request from the PAWW a yearly assessment of the condition of the city's water system in general and a report on any circumstances or conditions that would limit water connections in any area or zone for any reason.

10. New construction shall provide water conservation measures, and water conservation shall be encouraged for all new development. Water conservation measures shall include low flow water faucets, showerheads, and toilets for all new construction.

11. New developments shall be encouraged to use native plant species that are more drought resistant for landscaping. New commercial development shall be required to use native species for all landscaping.

12. New water wells shall minimize individual and cumulative adverse impacts on groundwater, streams, springs, or seeps, and their associated riparian habitats.

13. The construction of a new water well may only be permitted where it will not have significant adverse individual or cumulative impacts on groundwater, streams, or ESHA.

VII. Health & Safety, Page 18
B. The following policies governing water quality shall apply:

Minimize Introduction of Pollutants and Increases in Runoff

1. Development shall be designed and managed to minimize the introduction of pollutants into coastal waters (including the ocean, estuaries, wetlands, rivers, streams, and lakes) to the maximum extent practicable.

2. Development shall be designed and managed to minimize increases in runoff volume and peak runoff flow rate, to avoid detrimental water quality impacts caused by excessive erosion and sedimentation.

3. Consistent with section 30230 and 30231 of the Coastal Act, development shall not result in the degradation of coastal waters caused by the introduction of pollutants, or by changes to the landscape that adversely impact the quality, quantity, and flow dynamics of coastal waters.

Development shall not discharge runoff in a manner that adversely impacts the biological productivity and the quality of coastal waters appropriate to maintain optimum populations of marine organisms and protect human health.

Coastal Act Policies:
30230. Marine resources shall be maintained, enhanced, and, where feasible, restored.

Special protection shall be given to areas and species of special biological or economic significance. Uses of the marine environment shall be carried out in a manner that will sustain the biological productivity of coastal waters and that will maintain healthy populations of all species of marine organisms adequate for long-term commercial, recreational, scientific, and educational purposes.
30231. The biological productivity and the quality of coastal waters, streams, wetlands, estuaries, and lakes appropriate to maintain optimum populations of marine organisms and for the protection of human health shall be maintained and, where feasible, restored through, among other means, minimizing adverse effects of waste water discharges and entrainment, controlling runoff, preventing depletion of ground water supplies and substantial interference with surface water flow, encouraging waste water reclamation, maintaining natural vegetation buffer areas that protect riparian habitats, and minimizing alteration of natural streams.

Incorporate Site Design and Source Control BMPs; add Treatment Control BMPs as Required

4. All development shall incorporate Site Design and Source Control Best Management Practices (BMPs) to the maximum extent practicable, to minimize polluted runoff and water quality impacts resulting from the development. BMPs shall be selected to mitigate both construction-phase and post-construction water quality impacts. Where required (see 4.3), structural Treatment Control BMPs shall supplement Site Design and Source Control BMPS as necessary to protect coastal water quality.

VII. Health & Safety, Page 19
The definitions of Site Design, Source Control, and Treatment Control BMPs are as follows:

Site Design BMPs: Project design features that reduce the generation of pollutants or reduce the alteration of natural landscape features that protect water quality (e.g., minimizing impervious surfaces, or minimizing grading).

Source Control BMPs: Practices that reduce the entrainment of pollutants in runoff (e.g., covering trash receptacles, or minimizing the use of landscaping chemicals and irrigation).

Treatment Control BMPs: Structural systems designed to remove pollutants from runoff (using processes such as gravity settling, filtration, biological uptake, media adsorption, or any other physical, chemical, biological process) and/or to reduce runoff volume and peak flow rates (using systems such as grassy swales, infiltration basins, detention ponds, or dry wells).

5. The selection of appropriate BMPs to protect water quality shall be guided by the California Stormwater Quality Association (CASQA) Stormwater BMP Handbooks dated January 2003 (or the current edition), or an equivalent BMP manual that describes the type, location, size, implementation, and maintenance of BMPs suitable to address the pollutants generated by the development.

6. All development shall be evaluated by the City during the Coastal Development Permit (CDP) review process for potential adverse impacts to water quality. The applicant shall submit information that details how Site Design and Source Control BMPs will manage or mitigate polluted runoff and water quality impacts resulting from the development, consistent with Zoning Ordinance Section 5.33. These proposed measures shall be submitted for review and approval as part of the CDP application, or prior to issuance of the CDP.

7. All Coastal Development Permit approvals shall include conditions requiring the continued application, inspection, and maintenance of required BMPs as necessary to ensure their effective operation for the life of the development.

Developments of Special Concern

8. Certain categories of development have a greater potential for adverse coastal water quality impact, due to the development size, type of land use, or proximity to coastal waters. A development in one or more of the following categories shall be considered a Development of Special Concern, and shall be subject to additional requirements (see Policy 9, below) to protect coastal water quality:

Developments of Special Concern:
a. Housing development of ten units or more
b. Hillside residential development on slopes > 20 percent (as indicated on the “Natural Hazards” Opportunities and Constraints Map)Industrial developments VII. Health & Safety, Page 20
c. Commercial development if such development creates more than 5,000 square feet of impermeable surface or increases the impermeable surface on the property by more than 10% d. Retail gasoline outlet or automotive service facility e. Restaurant
f. Parking lot of 5,000 square feet or more of impervious surface area, or with 25 or more parking spaces
g. Re-development project that results in the creation, addition, or replacement of 5,000 square feet or more of impervious surface area on an already developed site, Commercial or industrial outdoor storage area
h. All development within 200 feet of the Pacific Ocean, or of a stream or river (including Point Arena Creek and Hathaway Creek), or discharges directly to a surface water (including wetlands, streams, or other coastal waters), if such development creates more than 2,500 square feet of impermeable surface or increases the impermeable surface on the property by more than 10% Development that discharges directly to the Pacific Ocean

9. All Developments of Special Concern (as identified in Policy 8, above) shall be subject to the following three additional requirements to protect coastal water quality:
a. The applicant for a Development of Special Concern shall be required to submit a Water Quality Management Plan (WQMP), certified by a California Registered Civil Engineer, estimating increases in pollutant loads and runoff flows resulting from the proposed development, and detailing the BMPs that will be implemented to minimize postconstruction water quality impacts. b. If the combination of Site Design and Source Control BMPs proposed for a Development of Special Concern is not sufficient to protect water quality, structural Treatment Control BMPs shall also be required. The Treatment Control BMPs to be implemented will be specified in the WQMP.

Concern shall be sized according to the following numerical design standard:

Where structural BMPs are required for post-construction treatment of runoff, structural BMPs (or suites of BMPs) shall be designed to treat, infiltrate, or filter the amount of stormwater runoff produced by all storms up to and including the 85th percentile, 24-hour storm event for volumebased BMPs, and/or the 85th percentile, 1-hour storm event (with an appropriate safety factor of 2 or greater) for flow-based BMPs.

10. In addition to all other applicable water quality requirements, developments with land use activities that have a high potential for generating pollutants shall be required to incorporate VII. Health & Safety, Page 21
BMPs to address the particular pollutants of concern. For example:
a) Require parking lots to incorporate BMPs to minimize runoff of oil, grease, car battery acid, coolant, gasoline, sediments, trash, and other pollutants to receiving waters. b) Require commercial developments to incorporate BMPs to minimize polluted runoff from structures, landscaping, parking areas, repair and maintenance areas, loading /unloading areas, and vehicle/equipment wash areas.
c) Require automotive service stations, car washes, and vehicle repair facilities to incorporate BMPs to minimize runoff of oil, grease, solvents, car battery acid, coolant, gasoline, and other pollutants to the stormwater conveyance system from areas including fueling areas, repair and maintenance areas, loading/unloading areas, and vehicle/equipment wash areas. d) Require restaurants to incorporate BMPs to minimize runoff of oil, grease, solvents, phosphates, suspended solids, and other pollutants.
e) Require outdoor material storage areas to be designed (e.g., with a roof or awning cover) to minimize runoff of toxic compounds, oil and grease, heavy metals, nutrients, suspended solids, and other pollutants.
f) Require roof or awning covers over trash storage areas to minimize off-site transport of trash and other pollutants.

VII. Health & Safety, Page 22
Other Land Use Activities

11. New development shall be encouraged to use drought-resistant native plant species for landscaping, to reduce the need for irrigation and landscaping chemicals (e.g., pesticides and fertilizers), and thus reduce polluted runoff. New commercial development shall be required to use native plant species for all landscaping.

12. Development shall be sited and designed to avoid, where feasible, construction on areas particularly susceptible to erosion, such as steep slopes. Development in these areas shall incorporate both construction and post-construction BMPs to reduce erosion and sedimentation.

Municipal Activities

13. The City should promote both the protection of good water quality and the restoration of impaired water quality. Water quality degradation can result from a variety of factors, including but not limited to the introduction of pollutants, increase in runoff discharge rate, generation of dry weather runoff, and alteration of physical, chemical, or biological features of the landscape.

14. The City should encourage and support public outreach and education regarding the water quality impacts of development. The City shall coordinate with other agencies in the watershed area, as feasible, to develop public education programs on urban runoff issues and the appropriate roles of individuals, businesses, and government in the implementation of BMPs for pollution prevention.

15. Storm drain stenciling or signage shall be provided for all new storm drain construction, to discourage dumping and other illicit discharges into the stormwater conveyance system.

16. The city should ensure that municipal maintenance activities and other public projects not requiring a Coastal Development Permit also integrate appropriate water quality BMPs.

17. Development shall be sited and designed to preserve the infiltration, purification, and retention functions of natural drainage systems that exist on the site, to the maximum extent practicable.

18. Drainage conveyed from the developed area of the site shall be conveyed in a non-erosive manner, to protect downstream areas from erosion and sedimentation.

19. Development shall be sited and designed to comply with the following principles to help protect water quality:
a) Protect areas that provide important water quality benefits, areas necessary to maintain riparian and aquatic biota, and/or that are susceptible to erosion and sediment loss; b) Analyze the natural resources and hazardous constraints of planning areas and individual development sites to determine locations most suitable for development; VII. Health & Safety, Page 23
c) Preserve and protect riparian corridors, creek channels, wetlands, and buffer zones; d) Minimize disturbance of natural areas, including significant trees, native vegetation, and root structures;
e) Ensure adequate setbacks from creeks, wetlands, Pacific Ocean, and other surface waters; f) Promote clustering of development on the most suitable portions of a site, taking into account geologic constraints, sensitive resources, and natural drainage features.

Minimize Impervious Surfaces

20. New development shall minimize the creation of impervious surfaces, especially directly connected impervious areas, to the maximum extent practicable. Redevelopment shall increase the area of pervious surfaces, where feasible.

21. The City shall promote the use of permeable pavement materials and techniques (e.g., paving blocks, porous asphalt, and permeable concrete).

Infiltrate Runoff

22. To the maximum extent practicable, development shall maximize on-site infiltration of runoff (to preserve natural hydrologic conditions, recharge groundwater, and prevent transport of pollutants), except where site conditions preclude infiltration (e.g., where geologic instability would be exacerbated, or pollutant concentrations are high). In developments where infiltration is precluded, appropriate Treatment Control BMPs such as filtration shall be implemented to reduce the discharge of polluted runoff. Single family residences are excluded from the requirement for treatment control BMPs where infiltration is precluded, unless the development is a Development of Special Concern.

23. Development shall divert runoff resulting from new impervious surfaces into landscaped areas or permeable surface areas, wherever feasible, to increase onsite infiltration and attenuate runoff.

24. To the maximum extent practicable, development shall limit the use of curb drains to avoid conveying runoff directly to the City’s stormwater conveyance system.

Minimize Polluted Runoff from Construction

25. Development shall minimize erosion, sedimentation, and other polluted runoff from construction-related activities, to the maximum extent practicable.

26. All development shall address construction-phase erosion and sedimentation, as well as other potential pollutants from construction sites (e.g., paint, solvents, vehicle fluids, and debris). Such VII. Health & Safety, Page 24
measures shall include controls on timing of grading, BMPs for storage and disposal of construction materials, and/or design specifications for sedimentation basins.

27. Grading shall be prohibited during the rainy season (from October through April) in areas with slopes of 20 percent or greater (as indicated on the “Natural Hazards” Opportunities and Constraints Map), except in response to emergencies.

Minimize Land Disturbance During Construction

28. Construction shall minimize land disturbance activities (e.g., clearing, grading, and cut-andfill), especially in erosive areas (including steep slopes, unstable areas, and in erosive soils), to minimize the water quality impacts of excessive erosion and sedimentation.

29. Construction shall minimize disturbance of natural vegetation (including significant trees, native vegetation, and root structures), and other physical or biological features important for preventing erosion and sedimentation.

30. Development shall incorporate soil stabilization BMPs on disturbed areas as soon as feasible, including, but not limited to, revegetation of graded or disturbed areas.

7. SEWAGE COLLECTION AND DISPOSAL POLICIES
The city's sewage collection and disposal system is owned and operated by the City of Point Arena. Sewer lines serve most of the existing developed area. The treatment includes aerated pond treatment, and chlorination, and percolation and evaporation for disposal. Areas not served are accommodated by individual septic tank systems.

A wastewater system capacity analysis was completed in January of 1996 by Bonneau Dickson, P.E. This study used buildout figures from density and Zoning allowed by this General Plan and it determined that: "The City of Point Arena wastewater system has adequate capacity to handle and treat the highest foreseeable flows and biochemical oxygen demand (BOD) loads that will be generated under the current General Plan, with the following exceptions:

1. The Capacity of the existing percolation ponds has been reached. It is extremely important to acquire additional area for percolation as soon as practicable.

2. Some parts of the sewer system might become hydraulically overloaded at some point in the future.

3. Slightly larger aerators might be needed in the distant future.

The average flows to the system, which currently are just under 30,000 gallons per day (GPD) in dry weather, are not important. The capacity of the system is limited not by the average flows but by the peak flows, which are occasionally 20 to 30 times higher than the average dry weather flows. Similarly, the ability of the plant to treat BOD does not impose a limit on the capacity of VII. Health & Safety, Page 25
the system. At worst, slightly larger aerators will have to be purchased as the existing units wear out. Earlier analyses of the capacity of the City's wastewater system which were based on average flows or BOD loads are not relevant.

The capacity of the sewer system is determined by the peak instantaneous flow that it will pass and will become inadequate only when there is an overflow from the system. The sewer system has never been known to overflow due to a lack of hydraulic capacity although some lines may have been close to their hydraulic capacities during the winter of 1995, at which time an instantaneous peak flow of 980,000 GPD was noted it is very difficult to predict the future maximum instantaneous peak flow. It may increase very little as new connections are made to the sewer system because the system may already be leaking at the maximum rate possible.

Sustained peak flows are caused by infiltration rather than by inflow into the sewer system, i.e. by leakage of ground water through many small places in the sewer system rather than by relatively large openings that allow stormwater to flow directly into the sewer system. There is unlikely to be any single leak that accounts for a large percentage of the total leakage, instead of the small leaks that are probably occurring in a large number of places. Correcting infiltration is very expensive because only a small amount of leakage is stopped by each repair.

Most of the leakage into the sewer system probably is coming from house laterals.

Approximately two-thirds of the sewer mains were slip lined in the early 1980's and most of the manholes were replaced at that time. By contrast to the relatively new sewer mains, many of the sewer laterals were built in the 1930s, when materials and construction methods were not nearly as advanced as they are today.

It is less costly and more certain to expand the percolation facilities than to undertake a large scale, general improvement of the sewer system."
The recommended improvements and activities and the recommended capital improvements of the Bonneau Dickson study have been accomplished or are incorporated into the polices below.

The following policies and programs shall apply:

1. The City shall take immediate steps to expand percolation capacity to accommodate sustained peak flows. This is of highest priority.

2. In order to protect ground water resources, all new development of more than one dwelling unit per acre of land will be required to connect to the municipal sewer system.

3. No sewer service may be extended to lands zoned Agriculture Exclusive-AE or to areas outside the "urban limit line".

4. All buildings that generate waste water must be connected with the sewer system if said buildings are within 100 feet of the system, or if said buildings are on a parcel less than one acre in size that is within 100 feet of the system.

VII. Health & Safety, Page 26

5. New private disposal systems shall not be permitted within the city, except those authorized by the City Council.

6. Improvements and or expansions to collection and treatment facilities that are necessitated by new development shall be financed all or in part by development fees.

7. The City should require that all future development also pay appropriate impact fees to finance the installation of adequate storm drainage infrastructure.

8. To reduce the sewage collection infiltration problem, and to further expand wet-weather sewage treatment capacity, the City should continue applying a testing and repair program to the sewage collection system.

9. The City should consider establishing a "sewer impact fee" that would replace the present "connection fee" (City Ordinance # 143). This fee shall be charged per ESD per connection and should be established by ordinance in connection with the actual cost of facilities replacement, repair, and maintenance to serve the use.

10. The City shall adopt an ordinance which requires that sewer laterals be tested when a building is sold and that leaky laterals be repaired or replaced and that adequate cleanouts be installed.

11. The City shall adopt a "capital improvement program" upon completion of the capacity and facilities study.

12. As a precautionary measure, when the population reaches 50% of projected buildout or in 50 years, whichever comes first, the City shall review sewer capacity to insure continue ability to meet waste water needs through buildout.

13. The City will require that the costs of sewer extensions and hookups for new developments be borne by the customer.

14. The City shall establish a protocol for visually observing the flows in various branches of the sewer system so that this information will be available for future sewer system analyses.

15. The City shall measure and map the depth of solids in the aeration basins on a yearly basis to determine rate of increase and estimate when solids will need to be removed. Test solids to help estimate cost of solids removal.

16. All sewer improvement programs shall conform with the provisions of the environmentally sensitive habitat areas (ESHA) policies, including but not limited to the riparian buffer zone for Point Arena Creek.

8. EMERGENCY PREPAREDNESS POLICIES
VII. Health & Safety, Page 27
Emergency preparedness is a term used in this general plan to refer to emergency medical and rescue services and police protection, and to disaster preparedness. Fire protection planning is addressed elsewhere in this element. Defense against catastrophes combines emergency response capabilities with policies and programs to minimize hazards. Minimizing hazards through planning is the principal focus of this element.

To prepare for emergencies the City shall accomplish the following:

1. The city shall update as necessary and maintain its disaster response plan.

2. The city shall prepare a specific earthquake preparedness plan and implementation program to deal specifically with preparation for and responses during an earthquake.

3. The City shall ensure continued fire and rescue services to the citizens of Point Arena through a joint powers agreement with the Redwood Coast Fire Protection District. City shall require all new developments to be in conformance with Uniform Fire Code.

4. The City shall establish an emergency alternative north-south route through or just outside of Point Arena.

5. Highway 1 leading north and south out of town, Riverside Drive, and Windy Hollow Road should be designated as the only available evacuation routes in case of an emergency.

9. POLICIES AND PROGRAMS GOVERNING HAZARDOUS MATERIALS
To protect citizens and visitors alike the following policies shall apply:

1. No hazardous waste dumps or incinerators will be allowed in the city.

2. The City shall work with the appropriate local, state and federal agencies to determine the extent of existing toxic waste sites. As of July, 1992, the California Environmental Protection Agency, Office of Environmental Information, has produced the following list of "Identified Hazardous Waste and Substances Sites:
a. 170 Main Street
b. 185 Main Street
c. 720 Port Road
d. 44900 Port Road
e. 415 School Street
All of the sites are listed for having leaking underground fuel storage tanks.

3. The City shall consider adopting a policy governing the transport of toxic and hazardous materials through town on local streets and on Highway 1.

VII. Health & Safety, Page 28
775 Baywood Drive
Suite 100
Petaluma, CA 94954
707.795.0900 phone
707.795.0902 fax
esassoc.com
memorandum
date May 5, 2025
to Paul Andersen, City of Point Arena
from Elijah Davidian, AICP, Shannon Fiala, and Louis White, PE subject Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00) Introduction
The City of Point Arena was recently awarded a grant from the California Coastal Commission (CCC) to assess the City’s exposure and vulnerability to sea-level rise related coastal hazards, including potential effects of climate change on Arena Creek. The vulnerability assessment was intended to inform an update of the City’s Community Health and Safety Element (CHSE) of the Local Coastal Program (LCP) as well. The purpose of this memo is to provide a summary of the results of the vulnerability analysis and to provide sea-level rise policy recommendations that the City may consider in its update to the CHSE.

Summary of Arena Cove Vulnerability to Sea-Level Rise
Hazards
Point Arena is home to a small coastal community and cove. The Cove serves as one of the only coastal access points in the region for several miles and provides a multitude of services including recreation and coastal access, habitat, a pier, and commercial boating facilities. Given the Cove’s unique location and low-lying terrain, it already experiences inundation during large storm events; however, as global temperatures warm and sea levels continue to rise, it is anticipated that the site will experience more frequent inundation and erosion because of larger waves and higher water levels.

The vulnerability assessment (VA) evaluated the potential vulnerability of Point Arena Cove to sea-level rise by considering the site’s exposure to current and future coastal hazards (e.g., flooding and erosion) as well as the relative sensitivity and adaptive capacity of the City’s assets to such impacts (ESA 2025). ESA performed a site survey and conducted community interviews to obtain a consensus concerning important community assets, which included the following: existing shoreline armoring; developed areas such as the pier, the parking lot and overflow parking, the historic U.S. Coast Guard (USCG) Boathouse, and private property; City utilities such as electric and sewer; recreational uses such as the picnic area, surfing spots, and beaches; and ecological assets such as potential Point Arena mountain beaver habitat, wetlands, and the bioretention basin. Each of these assets were evaluated for their exposure to current and future flooding and erosion.

Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
2 ESA evaluated historic flooding using nearby water level gauges as well as community in-person observations of historic flood events. ESA staff were also present during the January 5, 2023, storm to observe coastal flooding conditions, which were used to calibrate the future flooding estimates. Future flooding was evaluated using the Ocean Protection Council’s (OPC’s) medium-high risk scenario for 1.8 feet, 3.3 feet, and 6.7 feet of sea-level rise, which are anticipated to occur by the 2050, 2070, and 2100 time-horizons, respectively (OPC 2018, CCC 2018).

Current and future erosion were also analyzed for the same time-horizons and sea-level rise amounts. Observed historic erosion rates at the Cove or in the nearby vicinity were used to estimate potential future erosion rates, and these estimates were adjusted to account for anticipated increases associated with projected sea-level rise. ESA estimated potential future erosion distances of approximately 35, 50, and 95 feet for the years 2050, 2070, and 2100, respectively.

The results of the exposure analysis indicate that inundation extents for the current and future flood conditions do not differ greatly, as the surrounding steep terrain acts as a funnel for any overflow from either the sea or Arena Creek, but over time the wave hazards will progress landward. The VA indicates that the frequency, depth, and velocity of flooding will increase significantly with sea-level rise and climate change. Using a ranking system based on the combined aspects of exposure, sensitivity, and adaptive capacity, the following assets scored the highest for their vulnerability: the pier, historic USCG Boathouse, and sewer infrastructure. The next most vulnerable assets, with an overall vulnerability score of “medium-high” include electric utilities, private property, ecology and habitat, the parking lot, and the existing armoring (e.g., coastal protection structures). Lastly, the picnic area, event overflow parking, and recreational surfing scored a “medium” to “low-medium” in overall vulnerability. (Please see the full VA for additional details concerning the hazards analysis, methodologies, and vulnerability results).

Without any adaptive actions, the lower Cove area (i.e., the parking lot and adjacent infrastructure) is expected to continue flooding, and with sea level rise the shoreline surrounding the rock revetment is expected to erode. The VA is the first step in identifying community priorities and vulnerable infrastructure, and it serves as a foundation from which the City might develop future adaptation plans, policies, and implementation measures (e.g., a more comprehensive LCP amendment) as funding allows.

LCP Amendment Considerations
This section summarizes the existing CHSE and relevant state policies that should be considered when updating any portion of the LCP.

Existing Community Health and Safety Element
The City of Point Arena’s LCP (also known as the General Plan, or GP) was established in 1995 and later amended in 2001. The LCP guides development and protects coastal resources within the City’s coastal zone, consistent with the California Coastal Act of 1976, as amended. The entire city is within the coastal zone, as defined by the Coastal Act, and planning and development decisions within the City are therefore subject to the regulations set forth in the LCP. Point Arena’s LCP comprises eight elements, including land use and development, economic development, traffic and circulation, open space and conservation, community health and safety, noise, housing, and coastal. While sea level rise has implications for each of the topics addressed in the Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
3 various LCP elements listed, per the terms of the CCC grant funding the VA and associated policy recommendations, this memo focuses on the Community Health and Safety Element (CHSE).

The CHSE provides guidance on how the City can protect the community from “unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure, tsunami and seiche; slope instability due to mudslides and landslides; subsidence and other known geologic hazards; flooding; and wildland and urban fire.” (CHSE, Section VII (1)). Community hazard safety goals include protection from injury, loss of life and property damage and effective preparation and response to major emergencies.

The CHSE has not been updated since its adoption in 1995, and the list of hazards does not include sea-level rise.

This memorandum presents policy recommendations for incorporation into a future CHSE amendment. The City Council will ultimately determine the most appropriate policies for Point Arena. However, any proposed LCP updates should consider current CCC-recommended policies and guidance (see below), as CCC certification will be required before any such updates can take effect.

CCC Guidance (2018 SLR & 2021 Critical Infrastructure) and Consistency with Coastal Act
As mentioned above, any new LCP amendments will need to consider existing CCC guidance and policies. The CCC currently has several guidance documents and resources for local municipalities to consider when amending LCP policies. These guidance documents are summarized below for the City’s reference. In addition to the documents summarized below, the CCC released draft sea level rise guidance in 2018 pertinent to residential development1, but the guidance is not summarized below since it is in draft form and the VA did not identify residential development assets within the Point Arena Cove study area. ESA considered relevant guidance documents in its sea-level rise policy recommendations (below).

California Coastal Act (CCC 1976)
The CCC is the primary state agency charged with oversight of coastal development along California’s coastline.

The CCC oversees implementation of the California Coastal Act (Coastal Act 1976), which endeavors to balance coastal development with the protection of coastal resources. More specifically, the Coastal Act sets forth the policies and procedures that are to be used when establishing or amending LCPs (Chapter 6, Articles 1 and 2), requires the agency to consider sea-level rise in coastal resource planning and management policy decisions (30270). As the entire city is within the coastal zone, future LCP amendments must consider the effects of sea level rise, as applicable.

Sea Level Rise Policy Guidance (CCC 2018)
This document provides guidance for incorporating sea-level rise considerations into the planning and design of projects and policy documents for areas along the California coast within the jurisdiction of the CCC. Through the 2018 update to the guidance, the CCC adopted the OPC’s (2018) sea-level rise projections, as presented in California Sea-Level Rise Guidance (high emission scenarios only). The target audiences are applicants and agencies preparing coastal development permit applications and LCP updates. The guidance includes useful and 1 CCC, 2018. Draft Residential Adaptation Policy Guidance. Interpretive Guidelines for Addressing Sea Level Rise in Local Coastal Programs. March 2018. Available online at:
https://documents.coastal.ca.gov/assets/climate/slr/vulnerability/residential/RevisedDraftResidentialAdaptationGuidance.pdf Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
4 fundamental concepts for addressing sea-level rise in LCPs (Chapter 5) and application of the sea-level rise projections and development of adaptation strategies (Chapter 7). The recommendations in this memo and technical analysis in the Sea Level Rise Vulnerability Assessment for Arena Cove (ESA 2025) were completed prior to the issuance of the updated 2024 guidance. However, based on a review of the updated information, the findings and recommendations are not affected, as the projections that were used for the analysis have not significantly changed.

Critical Infrastructure at Risk: Sea Level Rise Planning Guidance for California’s Coastal Zone (CCC 2021)
The CCC prepared Critical Infrastructure guidance (CCC 2021) focused specifically on vulnerability and adaptation of high-risk transportation and water/wastewater facilities within the jurisdiction of the CCC. The guidance provides information on how to adapt transportation and water infrastructure (e.g., wastewater treatment, stormwater, and water supply facilities) for sea-level rise in a manner consistent with other existing statewide policies. The guidance emphasizes five key considerations: coordinated planning, environmental justice, phased adaptation, adaptation costs and funding, and nature-based adaptation strategies. The guidance also provides model policies that can be used to inform LCP updates (Appendix B).

Sea-Level Rise Policy Recommendations
The following policy recommendations address projected sea-level rise and its potential impact on coastal development and resources within the Point Arena Cove VA study area. The recommendations are consistent with current guidance (as mentioned above) and the VA, which is based on City Council goals and community input. The recommended policies recognize that sea-level rise projections are continually evolving and that the City endeavors to develop a formal adaptation plan in the future.

It should be noted that the following is not presented in terms of final policy language and that there are other sections of the LCP that may need to be updated as well to sufficiently address sea-level rise hazards.

General Policy Recommendations
As sea-level rise is not a CHSE-listed hazard, ESA recommends adding sea-level rise specifically to the list of hazards noted in Section 1 of the CHSE (Section VII). With all other goals and language remaining the same, ESA recommends adding a subsection to Section 3 of the CHSE with more specificity that might read as follows:

3.6 Sea-Level Rise Policies and Programs
Although the bluffs north and south of Arena Cove may also experience increased erosion due to sea-level rise, sea-level rise hazards for development in the City are focused in Arena Cove and Port Road. Sea-level rise hazards include erosion, wave runup and overtopping, and temporary inundation during large storm events from fluvial, coastal, and/or combined flooding, permanent inundation, groundwater rise, which are anticipated to increase in frequency and severity with sea-level rise.

The following policies and programs shall apply:

1. Siting to Protect Coastal Resources and Minimize Hazards: New development shall be sited to avoid hazards, taking into account predicted sea level rise, including groundwater changes, over the Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
5 anticipated life of the development. If hazards cannot be completely avoided, then development shall be sited and designed to protect coastal resources and minimize risks to life and property to the maximum extent feasible for the anticipated life of the development. New development shall assure stability and structural integrity of the development without reliance on shoreline protective devices that substantially alter natural landforms along bluffs and cliffs or otherwise harm coastal resources in a manner inconsistent with LCP policies or Coastal Act public access policies, and not contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area.

2. Best Available Science: Planning and development reviews in the City of Point Arena shall use, as applicable, the best available, up-to-date scientific information about projected sea-level rise and other climate change related coastal hazards, including the City of Point Arena Sea-Level Rise Assessment, CCC’s 2024 Sea-Level Rise Policy Guidance, and the State’s 2024 Sea-Level Rise Guidance. Coastal hazard mapping, vulnerability assessment, and LCP hazard policies shall be updated as the best available science and guidance becomes available, or as necessary to address significant changes in sea-level rise estimates.

3. Hazard Identification and Mapping: The City’s coastal hazard zones have been mapped using the best available science about projected sea-level rise, erosion, flooding, and other coastal hazards in the City of Point Arena Sea-Level Rise Assessment. Using the coastal hazard maps, site-specific hazard mapping and assessment shall be required for proposed development in the area mapped as “Future Coastal Flood Extent (6.7ft SLR)” as part of the individual development review process. Applications for Coastal Development Permits for development potentially subject to hazards from projected sea level rise, shall include a geologic/flood hazards report prepared by a licensed Geotechnical Engineer that evaluates the potential risk from inundation and/or coastal erosion over the economic life of the development. The report shall evaluate hazards in the context of a 6.7-foot sea level rise and include recommendations on development location, design, and construction to reduce risk from coastal hazards and avoid impacts to coastal natural resources.

The City shall reassess its Sea-level Rise Adaptation Plan (and any commensurate LCP amendments) every ten years at minimum. The reassessment shall consider the following:
• Efficacy of Adaptation Plan and implemented measures. • Updated sea-level rise projections and risks, using best available science. • Potential need to revise adaptation measures or implement new measures, including review of emerging engineering, science, and technologies.
• Funding needs and potential funding sources.
• Meaningful involvement of the public and environmental justice communities, including community-based organizations, in future adaptation planning. • Minimization of barriers to public coastal access or consideration of the public access needs of environmental justice communities.

Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
6 5. Critical Infrastructure: The City will pursue opportunities to preserve, protect and/or adapt as appropriate critical local infrastructure to protect public safety and mitigate against economic loss and reductions in coastal access.

Assumption of Risk: As a condition of coastal permit approval for new development in an area subject to current or future hazards, applicants shall be required to acknowledge and agree that the development is located in a hazardous area or an area that may become hazardous in the future. The applicant shall also acknowledge that sea level rise could render it difficult or impossible to provide services to the site; that new development waives any right to construct shoreline protective devices; that the boundary between public tidelands and private land may shift with rising seas and the development approval does not permit encroachment onto public trust land; that removal or additional adaptation strategies may be required in the future to address sea level rise consistent with the Coastal Act and the certified LCP; and that the applicant waives any future claims of damage or liability against the permitting agency and agrees to indemnify the permitting agency against any liability, claims, damages or expenses arising from any injury or damage due to such hazards.

Additional Policy Considerations for Current or Future LCP Updates The following section contains additional recommendations that the City may wish to consider as it evaluates potential changes to its LCP. Recommendations have been grouped by general category but may apply to multiple sections within the CHSE and/or other LCP elements. • Comprehensive LCP Review: ESA recommends that the City perform a comprehensive review of the entire LCP to determine whether there are other topics for which sea-level rise policies are warranted (e.g., protection of public access, recreation, and natural resources). It is ESA’s understanding that the City intends to address other sections of the LCP when additional funding is available and after the City is able to develop a more defined adaptation plan.
• Land Use Policies: ESA recommends that the City consider how sea-level rise may affect land uses (e.g., coastal access and recreation, designated conservation areas, private property rights, and development) and in return how existing land use policies may affect the community’s ability to adapt as sea levels rise. For example, as sea level rises, there may be a need to raise existing or new buildings above the future flood zone; however, if existing land use policies include height restrictions, this may limit the ability of the City to adapt in this manner.
• Notice of Hazards: Private property owners are not always aware that their property lies within an existing or future hazard zone. The CCC has often supported requirements to include notifications of hazards such as future flooding from sea-level rise in property transfers. The City may wish to consider something similar either in the new Sea-Level Rise Policy section or in other sections of the LCP. The policy could require, as a condition of approval for a coastal development permit on property containing any shoreline, geologic, flood, or fire hazards, the recordation of a deed restriction to ensure the current and any future owners of the property understand the presence and assume the risks of such hazards and any property defects or vulnerabilities related to such hazards, including information about known current and potential future vulnerabilities to hazards as may be exacerbated by climate change and sea level rise. • Armoring Allowances: As the City develops an Adaptation Plan and considers a variety of strategies, ESA assumes one of the strategies may be protection of some assets in place, such as existing critical infrastructure or coastal-dependent uses in imminent danger from erosion (i.e., when substantial evidence indicates that the Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
7 structure will be significantly damaged by coastal flooding or erosion hazards within two to three storm cycles, or approximately three years). Where protection is allowed under the LCP, ESA recommends that the City consider requiring analyses of alternatives to identify the least environmentally damaging alternative, including nature-based strategies, avoiding, minimizing and/or appropriately and proportionally mitigating all coastal resource impacts, limiting such developments to the minimum necessary to protect existing structures or beaches under threat of erosion, limiting the term of authorization for such protection, and requiring removal of armoring after it is no longer required or effective, as required by Coastal Act Sections 30235 and 30253. Additionally, future adaptation plans and LCP policies specifically relating to the armoring in Arena Cove that was authorized by Coastal Development Permit No. 1-20-0216 should consider Special Condition 8, which requires the City to analyze removal of the armoring if it is longer needed to protect the existing coastal dependent structures (i.e., the existing parking lot, or commercial fishing related structures). • Flood Hazard Policies and Programs. In order to achieve consistency with the newly proposed Sea-Level Rise Policies and Programs section, ESA recommends the following changes or additions to the Flood Hazard Policies and Programs section (3.2):
– Section 3.2 currently states that flood hazards are limited to the area along Arena Creek and to the “present parking area at Arena Cove.” With sea-level rise and climate change, this area will exponentially grow. ESA recommends that the City consider altering the language so that it is more flexible and/or denotes the potential for the area to grow with specifically sea-level rise, riverine flooding, and groundwater flooding.
– ESA recommends that the City update its Flood Control Plan to consider effects of compound flooding with sea-level rise and climate change.
– Section 3.2 (5) states that the City will be guided by the FEMA FIRMS dated June 3, 1986. Since FEMA periodically updates the hazard maps, for which sea-level rise will play an important role, ESA recommends that the City use more flexible language that allows for updates to science and hazard analyses without the need to update the entire LCP (i.e., removing the date of the FEMA FIRM and replacing it with language that references the “best available science”). – As sea levels rise, there may be a need for existing infrastructure to adapt in place. ESA recommends that the City consider adding language that will allow for floodproofing or elevating existing infrastructure where necessary to prevent harm to the public or the environment that may result from overflow during a flood event. Such language might include the following: “The City shall evaluate and pursue floodproofing of infrastructure and other development in danger from projected flooding by 2050. Allow and facilitate, if feasible, the floodproofing of infrastructure and associated structures, consistent with other LCP policies.” The City should consider refining the policy language to allow floodproofing of critical infrastructure assets, using best available science and consistent with CCC’s Critical Infrastructure At Risk guidance document.
• General Emergency Response: ESA notes that other sections of the CHSE and LCP refer to specific emergency response programs (e.g., Section 3.4 “Fire Protection Policies and Programs” and Section 8 “Emergency Preparedness Policies”). As existing and future coastal hazards will affect emergency response to and from Arena Cove, ESA recommends that the City add references in these sections or in the new SeaLevel Rise Policies and Programs section to ensure consistency. • Hazardous Waste Sites: ESA notes that although Section 9 of the CHSE (page 25) identifies two hazardous waste sites within the Cove and the existing flood hazard zone, we understand that the sites, which comprised leaking fuel tanks, were cleaned up as part of an EPA program and are no longer active.

Sea-Level Rise Policy Recommendations for Updates to the Community Health & Safety Element of the City of Point Arena’s General Plan/Local Coastal Plan (ESA Ref. D202201148.00)
8 References
California Coastal Commission (CCC), 2018, Sea-Level Rise Policy Guidance: Interpretive Guidelines for Addressing Sea-Level Rise in Local Coastal Programs and Coastal Development Permits, Original Guidance Adopted August 12, 2015, Update Adopted November 7, 2018.

California Coastal Commission (CCC), 2021, Critical Infrastructure at Risk, Sea Level Rise Planning Guidance for California’s Coastal Zone, Final Adopted Guidance, November 17, 2021.

California Coastal Commission (CCC), 2024. Sea level Rise Policy Guidance: Interpretive Guidelines for Addressing Sea level Rise in Local Coastal Programs and Coastal Development Permits. 2024 Update adopted on November 13, 2024. Accessed online:
https://documents.coastal.ca.gov/assets/slr/guidance/2024/2024AdoptedSLRPolicyGuidanceUpdate.pdf.

ESA, 2025, Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove, Prepared for City of Point Arena, ESA Ref. D202201148.00, May 2025.

Ocean Protection Council (OPC), 2018, State of California Sea-Level Rise Guidance, 2018 Update, Prepared by the California Natural Resources Agency and the California Ocean Protection Council, March 2018.

Ocean Protection Council (OPC), 2024. State of California Sea Level Rise Guidance: 2024 Science and Policy Update. Prepared by California Sea Level Rise Science Task Force, California Ocean Protection Council, California Ocean Science Trust. Accessed online: https://opc.ca.gov/wpcontent/uploads/2024/05/California-Sea-Level-Rise-Guidance-2024-508.pdf.

SEA-LEVEL RISE ANALYSIS AND VULNERABILITY

ASSESSMENT FOR POINT ARENA COVE
Technical Report
Prepared for May 2025
City of Point Arena

SEA-LEVEL RISE ANALYSIS AND VULNERABILITY

ASSESSMENT FOR POINT ARENA COVE
Technical Report
Prepared for May 2025
City of Point Arena
Services provided pursuant to this Agreement are intended solely for the use and benefit of the City of Point Arena.

No other person or entity shall be entitled to rely on the services, opinions, recommendations, plans or specifications provided pursuant to this agreement without the express written consent of ESA, 575 Market Street, San Francisco CA 94105.
775 Baywood Drive
Suite 100
Petaluma, CA 94954
707.795.0900
esassoc.com
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D202201148.00

Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove i ESA / D202201148.00 Technical Report May 2025

TABLE OF CONTENTS
Page

1. Introduction.....................................................................................................................1

1.1 Background.............................................................................................................1

1.2 Study Purpose.........................................................................................................2

1.3 Scope of Study........................................................................................................2

2. Project Setting................................................................................................................5

2.1 Study Area ..............................................................................................................5

2.2 Community Outreach and Engagement .................................................................6

2.3 Community Assets ..................................................................................................6

3. Historic and Existing Conditions ...............................................................................11

3.1 Historic Storms and Documented Impacts ...........................................................11

3.1.1 Analyzing Historic Water Levels ................................................................12

3.1.2 Observations from the January 5, 2023, Storm Event ..............................15

3.2 Existing Flooding...................................................................................................16

3.2.1 Tides and Water Levels .............................................................................17

3.2.2 Waves ........................................................................................................18

3.2.3 Creek Flooding...........................................................................................19

3.3 Extreme Event Flooding........................................................................................22

3.3.1 FEMA .........................................................................................................22

3.3.2 USGS Coastal Storm Modelling System (CoSMoS) .................................24

3.3.3 USGS 100-year Coastal Total Water Levels .............................................26

3.3.4 ESA’s Estimated Extreme Coastal Flooding .............................................27

3.3.5 ESA’s Estimated Extreme Fluvial Flooding ...............................................28

3.4 Influence of Filled Park Area on Flooding.............................................................30

3.5 Local Sediment Processes ...................................................................................31

3.5.1 Sediment Transport....................................................................................31

3.5.2 Historic Erosion..........................................................................................31

4. Future Conditions with Sea-Level Rise .....................................................................33

4.1 Relevant State Sea-Level Rise Guidance ............................................................33

4.1.1 California Strategic Plan to Protect California’s Coasts and Oceans 2020-2025 (Ocean Protection Council) .....................................................33

4.1.2 State of California Sea-Level Rise Guidance (Ocean Protection Council) ......................................................................................................34

4.1.3 Sea-Level Rise Policy Guidance (California Coastal Commission)..........34

4.2 Sea-Level Rise Projections...................................................................................34

4.3 Future Hazard Mapping ........................................................................................36

4.3.1 Future Coastal Flooding.............................................................................36

4.3.2 Future Fluvial Flooding ..............................................................................41

4.3.3 Combined Coastal and Fluvial Flooding....................................................44

4.3.4 Future Erosion............................................................................................45

5. Vulnerability Assessment ...........................................................................................49

5.1 Methodology..........................................................................................................49

5.1.1 Exposure to Hazard ...................................................................................49 Table of Contents
Page
Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove ii ESA / D202201148.00 Technical Report May 2025

5.1.2 Sensitivity to Hazard and Adaptive Capacity.............................................50

5.1.3 Overall Vulnerability ...................................................................................51

5.2 Point Arena Cove Vulnerabilities ..........................................................................51

6. References ....................................................................................................................55

7. List of Preparers...........................................................................................................57 List of Figures
Figure 1 Study Vicinity...........................................................................................................2 Figure 2 Study Area ..............................................................................................................5 Figure 3 Identified City Assets near Point Arena Cove.........................................................8 Figure 4 Identified City Assets within the Project Area.........................................................9 Figure 5 Assets Along Point Arena Cove Pier......................................................................9 Figure 6 Large Waves Destroy Pier During January 1983 Storm Event............................11 Figure 7 Cobble and Storm Debris Covering Arena Cove Parking Lot (January 6, 2023)..................................................................................................................12 Figure 8 Non-Tidal Residuals (2008 – Present Day)..........................................................13 Figure 9 Non-Tidal Residuals (2008 – Present Day), Associated Wave Characteristics, and Recent Large NTR Events (red).......................................13 Figure 10 Overtopping During January 5, 2023 Storm.........................................................15 Figure 11 Non-Tidal Residuals and Associated Wave Characteristics: January 5, 2023 Storm..................................................................................................................16 Figure 12 Sea-Level Rise Trend from Arena Cove Tide Gauge...........................................17 Figure 13 Wave Buoys Used in Analysis ..............................................................................18 Figure 14 Offshore and Nearshore Wave Characteristics from 1981-Present Day .............19 Figure 15 Modeled Point Arena Watershed..........................................................................20 Figure 16 Creek Overflow During January 10, 2023 Precipitation Event.............................21 Figure 17 Riverine Flooding Extent and Depth During January 10, 2023 Precipitation Event ..................................................................................................................22 Figure 18 FEMA Floodplain Classification............................................................................23 Figure 19 FEMA FIRM for the City of Point Arena................................................................24 Figure 20 Existing Flood Inundation for a 100-year Storm Event.........................................25 Figure 21 USGS Total Water Levels for Return Periods 1-yr to 500-yr ...............................26 Figure 22 Total Water Levels for Return Periods 1-yr to 100-yr...........................................27 Figure 23 Estimated Coastal Inundation During the January 5, 2023 Storm and a 100- Year Storm Event...............................................................................................28 Figure 24 Existing Riverine Flooding Depth and Extent for a 2-year Storm.........................29 Figure 25 Existing Riverine Flooding Depth and Extent for a 10-year Storm.......................29 Figure 26 Existing Riverine Flooding Depth and Extent for a 100-year Storm.....................30 Figure 27 Sea-Level Projections for Arena Cove..................................................................35 Figure 28 Future Inundation for a 100-year Storm with 0 to 6.6 Feet of Sea-Level Rise.....37 Figure 29 Total Water Level Return Period for Present and Future Conditions with Sea-Level Rise...................................................................................................38 Figure 30 Existing and Future Coastal Flood Hazard Zones................................................39 Figure 31 Future Inundation for non-storm conditions with 0 to 6.6 Feet of Sea-Level Rise ....................................................................................................................40 Figure 32 Predicted Peak Flows (cfs) in the Point Arena Watershed Under Future Climate Conditions.............................................................................................42 Figure 32 Existing and Future Fluvial Flooding Extent and Depths for the 2-, 10-, and 100-year Storm Events ......................................................................................43 Table of Contents
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Figure 34 Combined Coastal-Fluvial Flooding for a 100-year Storm: Existing and Future Conditions with 6.7ft of Sea-Level Rise .................................................44 Figure 35 Cobble Berm Profile Evolution with Sea-Level Rise.............................................46 Figure 36 Potential Erosion Hazard Zones with Sea-Level Rise..........................................47 Figure 37 Potential Shoreline Erosion with Sea-Level Rise .................................................48 Figure 38 Components of Vulnerability.................................................................................51 List of Tables
Table 1. Point Arena Cove Assets........................................................................................7 Table 2. Arena Cove Surveyed Assets.................................................................................7 Table 3. Recent Extreme Storms at Point Arena (2008 – Present Day)............................14 Table 4. Tidal datums at Arena Cove (#9416841)..............................................................17 Table 5. Summary of Existing Extreme Event Flows..........................................................28 Table 6. Watershed Average Percent Change in Future Extreme Rainfall........................41 Table 7. Hazard Exposure Scoring.....................................................................................50 Table 8. Hazard Sensitivity Scoring....................................................................................50 Table 9. Hazard Adaptive Capacity Scoring.......................................................................51 Table 10. Arena Cove Asset Vulnerabilities .........................................................................52 Table of Contents
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Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove 1 ESA / D202201148.00 Technical Report May 2025

1. INTRODUCTION
Though coastal communities are historically well-accustomed to occasional hazards such as flooding, wave overtopping, and erosion, climate change is forecast to increase exposure to coastal hazards. For coastal areas with intersecting river systems, the combined chance of marinefluvial flooding intensifies the risks of inundation and damage even more so. Identifying, preparing for, and adapting to the threats posed by sea-level rise will be one of the greatest challenges of the century. Local governments, agencies, and districts will be faced with significant challenges in continuing to provide basic services while adapting to the new paradigm posed by sea-level rise. Coastal communities in northern California are particularly vulnerable given their exposure to large storm systems that originate from the Pacific Ocean. The consequences of failing to adapt to vulnerabilities is potentially quite significant for society, public health, and the natural environment.

This document provides an informed assessment of the vulnerabilities of assets in the Arena Cove portion of Point Arena, focused on the developed area at the apex of the cove. The intent is that this information on exposures and vulnerabilities will support development of an informed and effective plan to adapt to these hazards.

1.1 Background
The City of Point Arena is a small coastal community in Mendocino County of approximately 450 residents within a 1.2-square mile area (Figure 1). It is home to Point Arena Cove and Pier and the Point Arena-Stornetta Lands of the California Coastal National Monument. The Pier serves both the commercial and recreational fishing communities, and the Cove provides the only water access for several miles, and the best small craft access between Noyo and Bodega (about 80 nautical miles). The City of Point Arena, a general law city incorporated in 1908, is located entirely in the Coastal Zone and is subject to the regulations of the California Coastal Act (1976).

The City is taking a proactive approach to determine potential impacts of sea-level rise on City assets and assess its vulnerability.

1. Introduction
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SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 1
Study Vicinity

1.2 Study Purpose
The City of Point Arena was recently awarded a grant from the California Coastal Commission (CCC) to assess the City’s exposure and vulnerability to sea-level rise related coastal hazards, including the potential effects of climate change on Arena Creek. The City seeks to conduct a vulnerability assessment to map coastal flooding and erosion hazards for existing and future conditions with sea-level rise, which will be used to inform an update to the Community Health and Safety Element of the City’s Local Coastal Program (LCP). The study will serve as a first step in evaluating the risk of the City’s assets, both natural and built resources and facilities, located near the coast. The study will also provide a basis for future studies that may develop and evaluate adaptation strategies to address said vulnerabilities. The goal for this study is to provide a realistic assessment of existing and future hazards that will incrementally advance the policy for local planning documents.

1.3 Scope of Study
The scope of the study included the following:

1. Data gathering: Gather and document data pertinent to City assets, historic ocean and creek flooding events, and projected future sea-level rise.

1. Introduction
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a. Inventory assets that are likely to be in the extreme coastal hazard zone. b. Engage with community members to collect in-person accounts of historic and current coastal conditions and extreme events (including the recent events such as January 5, 2023).
c. Summarize current scientific guidance for sea-level rise projections and policies.

2. Coastal hazards: Map coastal flooding and erosion hazards for existing and future conditions with sea-level rise using available hazard mapping and simplified methods. a. Determine likely landward extent of a 100-year event with over 6 feet of sea-level rise. b. Compare results of available hazard mapping with anecdotal evidence from recent or historic extreme events.
c. Work with the City to define a set of sea-level rise planning scenarios. d. Perform an exposure analysis to determine what critical infrastructure is most vulnerable to sea-level rise and when.

3. Arena Creek flooding: Conduct an initial coarse hydrologic and hydraulic analysis of Arena Creek to establish baseline conditions and consider how these conditions might change with future climate change.
a. Determine the likely precipitation rates for mean and extreme conditions, using nearby systems that include rain and flow gauges.
b. Develop a hydraulic model and run up to nine flow scenarios to map potential future conditions.

4. Community engagement: Engage with community members throughout the development of the vulnerability assessment to obtain and understand local stakeholder observations, perspectives, and priorities.

5. Policy recommendations: Provide coastal hazard-related policy recommendations that the City may consider for inclusion in its updates to the Community Health and Safety Element of the General Plan (GP) and LCP.

1. Introduction
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2. PROJECT SETTING
This section provides a synopsis of the study area as well as the City assets within it.

2.1 Study Area
This report focuses on the impacts of sea-level rise to the City of Point Arena, specifically Point Arena Cove (Figure 2) and City assets therein. As previously mentioned, Point Arena Cove is home to a pier, a boat launch, and recreational water and beach access for residents and tourists alike. The west-facing Cove is characterized by a cobble beach fronted by rocky reef and surrounding 150-foot-tall bluffs. Point Arena Creek flows into the ocean just south of the parking lot, adjacent to land fill north of the southern bluff. This study focuses specifically on Point Arena Cove because the community assets at risk of sea level rise are located at the Cove. Although City limits extend to the north and south of the cove, these areas are primarily high bluffs either owned privately with limited development (south of the Cove) or by the Bureau of Land Management (BLM) (i.e., Point Arena-Stornetta Unit north of the Cove).

SOURCE: Imagery (NOAA NGS 2023) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 2
Study Area

2. Project Setting
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During large precipitation and storm events, the Cove is susceptible to both marine and fluvial flooding. This study endeavors to summarize the magnitude and extent of both flooding sources as well as other coastal hazards, such as erosion.

2.2 Community Outreach and Engagement
ESA conducted community outreach and engagement in partnership with City staff on February 1 and 2, 2023. Initial outreach consisted of a community meeting on February 1st with approximately 20 attendees; subsequent outreach included interviews with individual stakeholders. The February 1st stakeholder meeting included an overview of the project goals and objectives, anticipated project timeline, state sea-level rise guidance, and coastal hazard processes and sea-level rise projections. ESA requested community input on asset identification, observations of historic flooding and erosion, and insights regarding other factors pertinent to vulnerability.

General community observations and priorities included the following (note community input has been grouped into categories for ease of reference):
• Erosion: Community members confirmed that the bluffs south of the community picnic area have been eroding due to wave undercutting.
• Overtopping:
– Waves overtop the revetments and flood the parking lot approximately every 2 to 3 years, and the degree of overtopping has been significantly worsening approximately every 5 years.
– When waves overtop the northern revetment, they reflect off of the northern bluff and will continue behind the Coast Guard Boathouse during large storm events (like the one on January 5th, 2023)
– Westerly and southwesterly swells tend to cause the most damage to infrastructure. • Recreational Assets: Community members confirmed the frequent usage of the Cove for surfing, picnicking, tide pooling, vehicular and maritime access to the shore. • Ecological Assets: Attendees mentioned that there used to be more fish (trout and steelhead, specifically) in the Creek and reaffirmed the importance of the Point Arena mountain beaver.

2.3 Community Assets
ESA staff visited the Cove in February of 2023 and met with City staff, City Council, and community members to discuss observations of historic flooding and identification of community assets potentially vulnerable to existing and future flooding with sea-level rise. Based on this meeting as well as prior meetings with City staff, ESA identified a number of assets within the project area with the potential to be affected by existing and future coastal hazards with sea-level rise (see Figures 3 - 5). The identified assets have been grouped into categories below (Table 1) for ease of reference; however, some assets (e.g., the beach) may in fact span one or more categories. The table does not include tribal or archeological resources that may or may not be present at the site. We understand that cultural resources surveys will be completed to support permitting and planning of other upcoming projects (e.g., pier upgrades).

2. Project Setting
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TABLE 1. POINT ARENA COVE ASSETS
Pier
Boat ramp
Storage
Floating platform
Harbor office
Boat Lift
Public restrooms
Fish cleaning stations
Pier
Shoreline Armoring
Revetment Seawall
Developed Areas
Parking lot Event/overflow parking Private property (e.g., restaurants and shops)
Historic Coast Guard
Boathouse
Utilities
Electric (e.g., vaults) Gas lines Sewer (e.g., manholes and pump station)
Water
Wastewater
Recreational
Picnic area Beach (north and south) Surf breaks (north and south) Ecological
Point Arena mountain beaver Wetlands Lagoon and creek Bioretention basins The Point Arena mountain beaver is a federally listed endangered subspecies found only in the vicinity of Point Arena and the southwest Mendocino County coast (USFWS 1998). Community members have indicated a handful of observations of the Point Arena mountain beaver on the hillslope on the south side of Arena Creek. Community members also identified an approximate wildlife corridor zone that is potentially used by species including the Point Arena mountain beaver. Note that the areas shown in Figure 3 are approximate and do not represent regulatory habitat zones or actual biological surveys. USFWS is currently initiating a 5-year review of the endangered status of the Point Arena mountain beaver (USFWS 2023).

ESA surveyed a portion of the assets identified above to ascertain an approximate estimate of existing asset elevations. Elevations of the surveyed assets are noted in Table 2 below and are referenced later in this report.

TABLE 2. ARENA COVE SURVEYED ASSETS
Asset Surveyed Elevation(s) (ft NAVD)
Pier 23
Parking lot 12 – 16
Creek 8 – 12 (thalweg to bank)
Beach 4.5 – 17
Seawall 16 – 18 (top)
Electric vaults 13
Sewer pump station 16 – 17
Sewer manholes 17
NOTES: Surveyed elevations have been rounded to the nearest whole digit and are not intended for design purposes.

2. Project Setting
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SOURCE: ESA 2023, Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 3
Identified City Assets near Point Arena Cove

2. Project Setting
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SOURCE: ESA 2023; Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 4
Identified City Assets within the Project Area
SOURCE: SHN City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 5
Assets Along Point Arena Cove Pier

2. Project Setting
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Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove 11 ESA / D202201148.00 Technical Report May 2025

3. HISTORIC AND EXISTING CONDITIONS

3.1 Historic Storms and Documented Impacts
The Point Arena community is no stranger to weathering large storms. Numerous news articles and blog posts1 may be found documenting the damage that has occurred to the nearby infrastructure over the last century. One particular storm on January 26, 1983 destroyed the pier and a fish house and severely damaged several other pieces of infrastructure within the Cove (see Figure 6). Other frequently documented impacts from large storms include overtopping of the revetment, flooding and deposition of cobble/gravel from the beach into the parking lot (Figure 7), and inundation into nearby private and retail buildings, among others.

SOURCE: “The Great Disaster at Arena
Cove” by Nicholas King
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 6
Large Waves Destroy Pier During January
1983 Storm Event
1 https://acornpartnersineducation.org/programs-events/students-protecting-the-coast/acorn-naturalist-guide/ naturalist-guide-point-arena-town-history/; http://kenjonesfishing.com/2015/04/point-arena-pier/; https://www.mendotraintony.com/mendocino-coast-ravaged-by-1983-storm/; https://mendofever.com/2023/01/09/city-of-point-arena-declares-a-local-emergency/

3. Historic and Existing Conditions
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SOURCE: Paul Andersen City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 7
Cobble and Storm Debris Covering Arena Cove
Parking Lot (January 6, 2023)

3.1.1 Analyzing Historic Water Levels
ESA obtained 1- and 6-minute water level measurements from the Arena Cove NOAA tide gauge and calculated non-tidal residuals (NTRs or residuals) for each dataset to determine the timing and magnitude of historic storm events within the Cove. NTRs are the “extra” water level that remains after the predicted water levels (tides) are subtracted from the observed water levels. In other words, NTRs are the result of waves, surge, and other events that are otherwise unaccounted for by the tidal predictions. For this study, assessment of the NTRs illustrates the dependence of local water levels on incident wave conditions, and for this site the coastal water elevation fluctuations increase well beyond the predicted tidal elevation for specific wave conditions, which increases the flooding and overtopping potential and vulnerability to storms.

Figure 8 below illustrates the results of the NTR calculations for the period of record (limited by the available 1-min data, which began in 2008). The blue lines indicate the 1-minute water level, NTRs, and difference between the 1- and 6-minute data, and the orange lines indicate the 6- minute water level and NTRs. The orange dots on Figure 9 show the coincident wave height, period, and direction for significant NTR events greater than 3 feet using the 1-min water level data. This indicates that the most extreme local NTR water levels at Arena Cove (i.e., NTR greater than about four feet) are associated with long period swells with offshore peak wave directions with a strong west component (i.e., ~260 to 300 degrees).

3. Historic and Existing Conditions
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SOURCE: Water level data (NOAA) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 8
Non-Tidal Residuals (2008 – Present Day)
SOURCE: Water level and wave data (NOAA) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 9
Non-Tidal Residuals (2008 – Present Day), Associated Wave Characteristics, and Recent Large NTR Events (red)

3. Historic and Existing Conditions
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Although noisier, the 1-min water level data provides a better synopsis of the actual water surface elevation fluctuations during extreme conditions than the 6-minute water level data, which is primarily used to represent still water level or tide conditions. The unique location of the tide gauge in Arena Cove makes it a valuable tool for observations of wave driven water level changes, commonly described as wave setup, or mor specifically, dynamic wave setup.

Based on ESA’s analysis, several recent significant storm events were noted on December 17-18, 2018; January 17-18, 2019; and January 5-8, 2023. Two tsunamis were also observed on March 11, 2011 and January 15, 2022. The NTRs for these events ranged from 1 to 6 feet. The full range of storm events, including date, NTR, and associated wave characteristics, are noted in Table 3 below.

TABLE 3. RECENT EXTREME STORMS AT POINT ARENA (2008 – PRESENT DAY) NDBC 46014 NDBC 46059
Date NTRa (ft) Hs (ft) Tp (s) Dp b (deg) Date NTR (ft) Hs (ft) Tp (s) Dp (deg) 1/5/2008 5.2 30 17 N/Ac 2/23/2008 4.3 33 13 N/A
2/24/2008 4.5 25 15 N/A 1/18/2010 4.2 N/A N/A N/A
1/19/2010 4.2 26 17 N/A 1/24/2010 3.3 N/A N/A N/A
1/25/2010 3.3 21 17 N/A 11/1/2010 4.2 27 19 N/A
11/2/2010 4.3 24 19 N/A 3/10/2011
(tsunami)

5.5 10 14 N/A
3/11/2011
(tsunami)

5.4 8 N/A N/A 3/31/2012 3.7 27 15 N/A
12/11/2015 4.6 30 17 280 12/10/2015 4.7 35 16 295
1/21/2017 5.2 30 19 275 1/20/2017 5.3 40 18 300
12/16/2018 4.9 26 16 285 12/16/2018 4.9 28 19 290
1/17/2019 4.8 25 16 270 1/16/2019 4.8 40 19 275
11/27/2019 3.1 37 15 300 11/26/2019 3.2 28 15 340
1/10/2021 3.2 20 17 300 1/10/2021 3.3 29 18 280
10/25/2021 4 24 16 300 10/24/2021 4.2 N/A N/A N/A
1/15/2022
(tsunami)

4.3 11 15 300 1/14/2022
(tsunami)

4.3 12 14 295
1/5/2023 6 33 17 250 1/4/2023 6 38 16 260
1/7/2023 3.7 20 16 260 1/7/2023 3.5 20 15 275
1/13/2023 4 22 19 245 1/12/2023 4 24 16 280
NOTES:
a NTRs noted are the maximum recorded during the event. b Degrees begin with 0 in the north and run clockwise.
c Wave period and direction were not available for the entire record. Wave direction was not recorded at either gauge until 2015.

SOURCE: Water level and wave data (NOAA), calculations (ESA)

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3.1.2 Observations from the January 5, 2023, Storm Event Of the significant storm events noted above, ESA was onsite to observe the most recent storm on January 5, 2023, which resulted in significant flooding of the Cove (see Figure 10). During the event, large waves overtopped the seawall and inundation extended across the majority of the parking lot, carrying cobble and large logs with the wave boar. Wave crests were also observed to nearly reach the bottom of the pier. In addition, the power in the Cove was lost, and because there was no backup generator, neither the boat hoist on the pier nor the sewer lift station were operable.

SOURCE: Louis White (ESA) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 10
Overtopping During January 5, 2023 Storm
ESA performed post-storm analysis to obtain the water levels, NTRs, and wave characteristics for the event (Figure 11). NTRs were noted as high as 3 to 6 feet above predicted water levels (for the 6-minute and 1-minute averages, respectively). Offshore wave heights reached peaks ranging from 302 to 383 feet, coming from a predominantly westerly direction (Figure 11). Nearshore wave heights closer to the Cove reached approximately 17 feet at an 18 to 20 second period with 2 Point Arena Buoy, 46014 NDBC 19 nautical miles north of Point Arena. Available:
https://www.ndbc.noaa.gov/station_page.php?station=46014 3 West California Buoy, 26059 NDBC 357 nautical miles west of San Francisco. Available:
https://www.ndbc.noaa.gov/station_page.php?station=46059

3. Historic and Existing Conditions
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a direction of about 250 to 270 degrees (Figure 11).4 Based on offshore and nearshore wave heights, ESA computed a total water level of approximately +30 feet NAVD for the January 5, 2023 event.

SOURCE: Water level and wave data (NOAA) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 11
Non-Tidal Residuals and Associated Wave
Characteristics: January 5, 2023 Storm

3.2 Existing Flooding
This section provides a synopsis of the existing conditions for the three main flood sources (tides, waves, and the creek) within Point Arena Cove. Existing hydrologic conditions are important to understand because they form the foundation for projected changes with sea-level rise. 4 CDIP MOP MO-149 https://cdip.ucsd.edu/mops/?moplist=Mendocino_County&xitem=info&mop=M0149

3. Historic and Existing Conditions
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3.2.1 Tides and Water Levels
Point Arena experiences mixed semidiurnal tides, or two daily high tides and two daily low tides of differing elevations. These daily tides also vary with the spring-neap tidal cycles, which occur approximately twice a month.

Coastal engineers use vertical datums, or defined reference surfaces, to estimate the relative elevation of the tides and water levels to the land around it. Measuring the water levels over prolonged periods provides a baseline for understanding typical water levels and how they may change over time. For this study, ESA used the closest NOAA tide gauge: Arena Cove (Station #9416841), located in the middle of the Cove. Tidal datums for the gauge are shown in Table 4.

TABLE 4. TIDAL DATUMS AT ARENA COVE (#9416841)
Tidal datum Abbreviation ft NAVD
Maximum Observed Tide (observed on February 6, 1998) MOT 8.53 Highest Astronomical Tide HAT 7.48
Mean Higher High Water MHHW 5.73
Mean High Water MHW 5.06
Mean Tide Level MTL 3.04
Mean Sea Level MSL 3.00
Mean Low Water MLW 1.01
Mean Lower Low Water MLLW -0.14
NOTES: The tidal datums listed above are from the most recent tidal epoch: 1983-2001.

SOURCE: NOAA Tides and Currents 2020
The record for the Arena Cove tide gauge dates back to 1978. The relative sea level trend recorded over this period (Figure 12) is 0.86 mm/year, which is equivalent to 0.28 ft over 100 years.

SOURCE: NOAA City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 12
Sea-Level Rise Trend from Arena Cove Tide Gauge

3. Historic and Existing Conditions
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3.2.2 Waves
The study area is exposed to large swell and large storm seas. The majority of the wave exposure comes from the north Pacific, with swell primarily from between the west and northwest directions. Strong winds and seas can also arrive from these directions as well as the south through southwest. Swells from the southern hemisphere also reach the study area and occasionally with relatively high power (very long wave lengths associated with long travel distances), although they are generally smaller than the north Pacific swells. Based on input from local community members (see Section 2.2), the most damaging storms have come from the westsouthwesterly direction.

Offshore and nearshore wave characteristics for the study area (e.g., significant wave height, peak wave period, dominant wave direction, and wave power) are shown in Figure 14 below.

Additional information can be obtained from the closest wave buoys (Figure 13):
• Nearshore (CDIP M0149)5
• Point Arena (NBDC 46014)6
• West California (NDBC 46059)7
SOURCE: Imagery (Earthstar Geographics) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 13
Wave Buoys Used in Analysis
5 https://cdip.ucsd.edu/mops/?moplist=Mendocino_County&xitem=info&mop=M0149 6 https://www.ndbc.noaa.gov/station_page.php?station=46014 7 https://www.ndbc.noaa.gov/station_page.php?station=46059

3. Historic and Existing Conditions
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SOURCE: Wave data from NOAA and CDIP City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 14
Offshore and Nearshore Wave Characteristics from
1981-Present Day

3.2.3 Creek Flooding
ESA conducted an initial hydrologic and hydraulic analysis of Arena Creek to assess current flood challenges and how riverine flooding will change under future climate change conditions.

The following sections describe the methodology and provide an overview of existing flooding conditions based on a recently observed storm event (January 10, 2023) with high rainfall.

Methodology
The Point Arena watershed (Figure 15) was simulated in HEC-HMS 4.10, a software used to simulate complete hydrologic processes for watersheds, to determine flows for mean and extreme flood conditions. The Point Arena watershed was first delineated using USGS StreamStats.8 8 StreamStats is a USGS web application used to delineate drainage areas and estimate basin characteristics on userselected sites on streams. Accessed at https://streamstats.usgs.gov/ss/. 0 10
20 30
40 50
Sig Wave Height (ft)
NDBC-46059 (Depth: 15220 ft)
NDBC-46014 (Depth: 1680 ft)
MOP-M0149 (Depth: 49 ft)
0 5
10 15
20 25
Tp (sec)
0 100
200
300
400
Dp (Deg)
1980 1985 1990 1995 2000 2005 2010 2015 2020
Date & Time (PST)
10 2
10 4
10 6
Wave Power (ft.lb/sec/ft)

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SOURCE: NOAA 2017 LiDAR City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 15
Modeled Point Arena Watershed
The watershed was modeled using the Soil Conservation Service (SCS) Unit Hydrograph method to compute a runoff hydrograph. The SCS Unit Hydrograph method is based on the concept of a unit hydrograph, which represents the response of a watershed to a unit amount of rainfall over a specific duration. Key inputs to the SCS Unit Hydrograph method are the curve number and percent imperviousness. The curve number is an empirical parameter used for predicting direct runoff and infiltration from excess rainfall and is a function of land use and soil type. Soil data was retrieved from the USGS Web Soil Survey while land use data was retrieved from the 2019 National Land Cover Database (NLCD 2019). Percent imperviousness represents the percentage of the watershed that consists of impervious surfaces such as roads, roofs, and other paved surfaces and was derived using the NLCD 2019 dataset. Higher curve number values and percent imperviousness values represents higher runoff potential which will increase peak flows.

Peak flows obtained from HEC-HMS were simulated using the HEC-RAS 6.3.1 hydraulic model.

ESA developed a two-dimensional (2D) hydraulic model to evaluate the flood extents of mean and extreme events. The 2D model allows for a more accurate representation of complex flow patterns and hydraulic interactions with topographic features. The terrain for the 2D hydraulic model was derived using a 2017 FEMA LiDAR flight (OCM Partners, 2023). Cell-spacing for the grid was set to 10-feet. Base Manning’s roughness, an empirical parameter used to define resistance to flow, for the hydraulic model was set to 0.05, while calibrated regions were used to assign a Manning’s roughness of 0.016 for impervious surfaces such as Port Road and the Point

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Arena parking lot and a Manning’s roughness of 0.13 for densely vegetated areas such as those along Port Road.

Modeled Creek Flooding Event (January 10, 2023)
Observations of creek flooding occurred most recently during a high precipitation event on January 10, 2023. The event caused severe creek flooding and overflow onto Port Road, the sole access road leading into and out of the Cove (see Figure 16). Observations from this event were used to verify the results of the fluvial model as described below.

SOURCE: Paul Andersen 2023 City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 16
Creek Overflow During January 10, 2023 Precipitation Event The January 10, 2023 rainfall event peak flow was estimated using the hydrologic model in HECHMS and routed in HEC-RAS. No rain gauges with recent data exist within the immediate vicinity of Point Arena. Therefore, the Boonville rain gauge, located approximately 20 miles east of Point Arena and managed by the California Department of Water Resources, was chosen instead. A scaling factor equivalent to the ratio of the mean annual precipitation of the Point Arena basin to the mean annual precipitation of the Boonville rain gauge was used to amplify the precipitation data for the January 10, 2023 rainfall event. The corresponding peak flow was then estimated in HEC-HMS and simulated in HEC-RAS. The flood extents were then compared to observed flooding from the storm event to verify the HEC-HMS inputs and peak flow. Flood extents for the January 10, 2023, rainfall event are shown in Figure 17.

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SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 17
Riverine Flooding Extent and Depth During
January 10, 2023 Precipitation Event

3.3 Extreme Event Flooding
Several sources are available with which to estimate the magnitude and extent of an existing 100-year storm (i.e., a storm with a 1% annual chance of occurrence): the Federal Emergency Management Agency (FEMA) and the U.S. Geological Survey (USGS). The following subsections briefly describe and provide local results for each source as well as results for analyses performed by ESA.

3.3.1 FEMA
FEMA develops Flood Insurance Studies (FISs) and Flood Insurance Rate Maps (FIRMs) for the purpose of informing the public of flood risks, to inform building policy in risk-prone areas, and to control the chance of damage to property. FEMA FIRMS typically show colored zones indicating the extent of the 1% (100-year) and 0.2% (500-year) annual chance flood events. These events can happen as a result of flooding from coastal flood sources (ocean water levels and waves), precipitation flood sources (high freshwater runoff), or a combination of both (as is the case for Arena Cove).

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Within the flood hazard zone (also known as the 100-year floodplain), FEMA further categorizes zones of relative hazards in terms of the wave height and flow rate (see Figure 18). The zones are intended to relate the potential damage that may occur within the floodplain as a result of the intensity of flooding. It is important to note that FEMA only considers existing conditions and does not account for long-term coastal erosion or sea-level rise in its mapping.

SOURCE: CDWR 2020 City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 18
FEMA Floodplain Classification
The latest FIRM for Point Arena Cove, dated July 18, 2017, is shown in Figure 19 and includes a coastal “VE” zone and a fluvial “A” zone. The coastal VE zone specifies a base flood elevation (BFE) of 32 feet NAVD, which for coastal areas is the 100-year total water level (i.e., elevation of the 100-year wave runup elevation). This implies that any assets located seaward of the orange line in Figure 12 and at or below this elevation are already exposed to flood inundation during a 100-year event. No elevation is specified for the A zone. The FEMA mapping is approximate landward of the orange line, with the landward hazard zone based on the creek flood source.

Based on historic and recently observed events (see Figure 10), it would appear that the FEMA FIRM underpredicts the extent of the 100-year floodplain and high-velocity hazards actually extend further into the developed area.

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SOURCE: FEMA 2017 City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 19
FEMA FIRM for the City of Point Arena

3.3.2 USGS Coastal Storm Modelling System (CoSMoS)
The USGS’s Coastal Storm Modeling System (CoSMoS) (Barnard 2019) provides storm-induced coastal flood and erosion hazard mapping for both current and future conditions, including a range of storm scenarios (i.e., return periods). Though the online mapping provides flood depths, the map is most useful for visualizing flood inundation (depicted in blue) and wave runup (depicted as small green dots) extents.

Figure 20 shows the existing coastal flood hazard with a 100-year event, essentially the same scenario as the FEMA maps. Flood depths are indicated by the blue shading with darker shading indicating greater depth (see legend). The shaded areas indicate water depths that persist for several minutes, and do not include the shorter bursts of high velocity wave runup extending farther landward and higher. The extent of wave runup is located by the green dots, which extend landward of the shaded flood areas.

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Note that FEMA considers flooding to extend to the limits of wave runup, which can also cause structural damage and scour. Hence the ‘green dots’ on the CoSMoS map should be compared to the flood limits in the FEMA map. Compared to both the FEMA FIRM as well as ESA’s analysis (see Section 2.3.4 below), the extent of wave runup modeled by CoSMoS may be over-estimated in this case given the local topography (i.e., cove surrounded by steep bluffs).

SOURCE: USGS City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 20
Existing Flood Inundation for a 100-year Storm Event

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3.3.3 USGS 100-year Coastal Total Water Levels
A recent study by the USGS (Shope et al. 2022) computed total water levels every 100 meters for the entire West Coast and a range of return periods (1-year through 500-year). These values supersede those provided in CoSMoS (see Section 3.3.2). Three USGS transects intersect Point Arena Cove: transect ID 12692, 12691, and 12690, noted in the below figure as “north, “middle”, and “south”. Figure 21 shows USGS’s total water level estimates for each transect and the full range of return periods. The 100-year total water level, as estimated by the USGS analysis, is in the range of +23 to +31 feet NAVD. The largest of the USGS estimated total water levels is comparable with the BFE estimated by FEMA (+32 feet NAVD) though lower than the 100-yr total water level estimated by ESA (+33 feet NAVD, see section 2.3.4).

SOURCE: USGS 2022 City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 21
USGS Total Water Levels for Return Periods 1-yr to 500-yr

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3.3.4 ESA’s Estimated Extreme Coastal Flooding
To perform a more site-specific analysis, ESA also calculated total water levels (TWLs) for a range of return periods under existing conditions (Figure 22). The TWLs were calculated from a 63-year time series (1960-present day) of coincident wave and water levels used by FEMA for their coastal flood analysis (FEMA 2014). Based on ESA’s analysis, the 100-year total water level is approximately +33 feet NAVD for existing conditions.

City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 22
Total Water Levels for Return Periods 1-yr to 100-yr
ESA used in-person observations from the January 5, 2023 storm event to calibrate the total water level calculations above and to map the approximate inundation extent of a 100-year storm (Figure 23). Compared to the FEMA and CoSMoS 100-year landward flood extents, ESA’s estimates were closer to CoSMoS’ modeled landward extents of inundation, which is more extensive than FEMA’s.
100-year =
33 ft NAVD

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SOURCE: Imagery (NOAA
NGS 2023)
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 23
Estimated Coastal Inundation During the January 5, 2023 Storm and a 100-Year Storm Event

3.3.5 ESA’s Estimated Extreme Fluvial Flooding
The 2-year, 10-year, and 100-year flows were obtained from HEC-HMS 4.10 using the frequency storm method, which transforms precipitation depths for a given storm duration into a design hydrograph. The extreme event flows are summarized in Table 5.

TABLE 5. SUMMARY OF EXISTING EXTREME EVENT FLOWS
Extreme Event Flow (cfs)
2-year 279.7
10-year 618.4
100-yr 1068.3
The extreme event flows were modeled in HEC-RAS as a quasi-unsteady-state simulation. The maximum flows were applied at the upstream end of the model domain and were held constant during the simulation period. A constant tailwater elevation equivalent to MHHW plus one foot was selected at the downstream end of the model domain. During extreme rainfall events, it was assumed that the cobble beach berm is scoured out. Surface differencing between the 2017 FEMA LiDAR and a previous 2016 USGS LiDAR dataset revealed that the 2017 FEMA LiDAR depths in the downstream creek channel were several feet lower than that of the 2016 USGS LiDAR data. Additionally, the cobble beach berm elevations that were surveyed in March 2023 are not present within the 2017 FEMA LiDAR, indicating that the LiDAR data was flown when the Point Arena creek was in a scoured state. Figures 24-26 map the flood extents for the existing extreme events.

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SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 24
Existing Riverine Flooding Depth and Extent for a 2-year Storm SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 25
Existing Riverine Flooding Depth and Extent for a 10-year Storm

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SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 26
Existing Riverine Flooding Depth and Extent for a 100-year Storm

3.4 Influence of Filled Park Area on Flooding
Note that the presence of the filled “park” area on the south bank of Arena Creek, which is an elevated area overlooking the beach and the parking, and which includes a picnic area, appears to greatly influence the direction of fluvial flooding onto the parking area. The park is an artificially filled area, which was developed when the parking area of the cove was constructed by filling the historic lagoon with material. Based on observations of the creek flows and flooding, the park feature deflects creek flows to the north toward the parking area. The parking lot was constructed at a very low elevation in the lagoon floodplain, and thus is already vulnerable to regular flooding.

The park area tends to enhance the flooding by deflecting all flows toward the parking and forcing the creek to flow through a narrow corridor. The reaction to the creek flooding has been to construct a short berm separating the parking and the creek, but coastal wave events move cobble and beach sediments into the creek mouth, which tends to also block the fluvial flows. We hypothesize that under historical conditions, where the lagoon was much wider with a back-beachlagoon interface along a longer reach, the lagoon would fill during rain-driven fluvial events and then would drain through a channel that would route across the beach along the tall hillside and bluff. Lagoons in California that are “perched” above the tides, such as at Arena Creek, tend to intermittently blow out and drain across the beach (Behrens et al. 2015). Lagoons with coarse cobble beaches also tend to have more permanent “overflow” channels draining the lagoon over the beach when the water level in the lagoon exceeds the low point of the beach berm.

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3.5 Local Sediment Processes
The following sections discuss coastal sediment transportation processes within the study area.

These processes are important to understand because they influence how the coastline has historically responded to sea-level rise and extreme events and therefore how it might respond to sea-level rise in the future.

3.5.1 Sediment Transport
The section of coastline within the study area is characterized by a cove with cobble/gravel beaches, rocky offshore reefs, and surrounding steep bluffs. Sediment sources for the Cove are the creek, which delivers sediment during large precipitation events, erosion of the adjacent bluffs, and onshore transport via waves. Sediment sinks for the Cove are offshore transport via waves and anthropogenic removal of beach sediment by local residents after storms wash them onto the Cove parking lot.

3.5.2 Historic Erosion
Data concerning historic coastal erosion rates is generally difficult to come by. For this study, ESA used information from a Philip Williams & Associates (PWA, now ESA) report that analyzed the effects of sea-level rise on coastal erosion throughout the State of California (2009).

Much of the historical data from the PWA report was sourced from two USGS shoreline change reports (Hapke et al. 2006, Hapke and Reid 2007) that included long-term erosion rates for sandy and cliff-backed shorelines (i.e., bluffs). Historic shoreline change rates within the project area ranged from -0.07 to -0.16 meters per year (-0.23 to -0.52 feet per year); however, information for the Cove itself was limited to two shoreline stretches on the northern side of the Cove. For reference, historic erosion rates just south of the Cove ranged from -0.13 to -0.15 meters per year (-0.43 to -0.49 feet per year), which is comparable to other adjacent and similarly-oriented shorelines in the larger area.

Anecdotal observations of erosion of the filled park area on the south side of Arena Creek by community members indicate that fill comprising the park area has eroded significantly over the past decade. No estimates of erosion rates are available for this location.

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4. FUTURE CONDITIONS WITH SEA-LEVEL
RISE
The following section summarizes state sea-level rise guidance, regional sea-level rise projections, and available coastal hazard maps for projected future conditions with sea-level rise over the next century.

4.1 Relevant State Sea-Level Rise Guidance
Pertinent policies and guidance concerning sea-level rise projections and planning in the State of California are outlined below. The following is not an exhaustive list, and it is important to note that such policies are often being updated due to frequent updates in climate science as more data is collected and future projections based on historic data are revised. The OPC updates sea-level rise guidance for planning approximately every 5 years. The technical work in this assessment was completed prior to the issuance of the latest OPC (2024) sea-level rise guidance and is based on the prior guidance from 2018. However, the changes to the sea-level rise guidance and projections do not affect the analyses and sea-level rise amounts used in this report. The main change in the guidance is that the extreme sea-level rise projection (i.e., H++) has been removed from the current state guidance of OPC (2024) and CCC (2024).

4.1.1 California Strategic Plan to Protect California’s Coasts and Oceans 2020-2025 (Ocean Protection Council)
The California Ocean Protection Council published the California Strategic Plan to Protect California’s Coasts and Oceans 2020-2025 (OPC 2020)9. Objective 1 of the plan states:
“Objective 1.1Build Resiliency to Sea-Level Rise, Coastal Storms, Erosion, and Flooding “1.1.1: Ensure California’s coast is resilient to at least 3.5 feet of sea-level rise by 2050, as consistent with the State’s Sea-Level Rise Guidance Document as appropriate for a given location or project. This target will be modified periodically based on the best available science and updates to the State’s Sea-Level Rise Guidance Document.” This objective calls for coastal development to be adapted to withstand 3.5 feet of sea-level rise, with the adaptation implemented by 2050. Note that the 2050 date is a goal for implementation of the adaptation, in anticipation of future sea levels reaching 3.5 sometime after that date. 9 https://www.opc.ca.gov/webmaster/ftp/pdf/2020-2025-strategic-plan/OPC-2020-2025-Strategic-Plan-FINAL20200228.pdf

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4.1.2 State of California Sea-Level Rise Guidance (Ocean Protection Council)
The OPC adopted sea-level rise guidance in March of 2018 that updated the previous state guidance based on advances in climate science. The OPC guidance provides a synthesis of sealevel rise science and projected rates for the state of California, steps for local governments and state agencies to incorporate sea-level rise science into permitting, planning, and investment decisions, and preferred adaptation approaches. The vulnerability assessment and adaptation strategy recommendations in this report are intended to be consistent with the sea-level rise projections and adaptation strategy recommendations within the OPC’s sea-level rise guidance.

This guidance was superseded by updated guidance OPC (2024), which dropped the extreme sealevel rise projection.

4.1.3 Sea-Level Rise Policy Guidance (California Coastal Commission)
This document provides guidance for incorporating sea-level rise considerations into planning and design of projects and policy documents for areas along the California coast within the jurisdiction of the CCC. The 2018 update to the guidance adopted the sea-level rise projections presented in the OPC (2018) California Sea-Level Rise Guidance (high emission scenarios only).

The target audience are applicants and agencies preparing Coastal Development Permit applications and Local Coastal Program updates. The guidance includes useful and fundamental concepts for application of the sea-level rise projections and development of adaptation strategies.

Chapter 7, “Adaptation Strategies,” discusses four adaptation strategies: accommodate, protect, hybrid, and retreat. This report and ESA’s recommendations herein are intended to be consistent with the CCC’s Sea-Level Rise Policy Guidance. This document was updated in 2024 to comply with the changes in the OPC (2024) document (CCC 2024).

4.2 Sea-Level Rise Projections
Projections of global sea-level rise are well-documented and investigated, with recent research projecting sea-level rise on the order of 2 to 10 feet by 2100 in California (e.g., Cayan et al. 2009, Griggs et al. 2017). This research has been used to develop a series of policy guidance documents by the State of California that have recommended including specific amounts of sea-level rise in project planning and design, which were described in section 3.1 (Relevant State Sea-Level Rise Guidance).

While large-scale (global- or state-level) sea-level projections have existed for several decades, smaller scale (e.g., region- or county-scale) estimates have only become readily-available in recent years. This is partly because of advances in techniques to downscale global climate models for parts of the California coast, and also because of an effort to consider local rates of vertical land motion (VLM). Projections of sea-level rise vary along the coast of California due to the regional oceanic effects as well as VLM. Beside varying geographically, the projections also vary based on the selection of future global emissions scenarios (e.g., greater levels of carbon emissions relate to higher sea-level rise). The following paragraphs provide a general summary of

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the sea-level rise science that has been developed for California, specifically within the study area region.

Climate models show strong agreement on the amount of sea-level rise that is likely to occur by 2050 and start to diverge after 2050 based on the range of potential emissions scenarios. The OPC 2018 Sea-Level Rise Guidance provides probabilistic projections of sea-level rise and categorizes them into recommended low risk aversion, medium-high risk aversion, and extreme risk aversion projections.

These risk aversion categories are intended to be selected based on a project’s apparent level of tolerable risk and its ability to adapt to future sea-level rise. The low and medium-high risk aversion scenarios are probabilistic projections where “low” represents the upper bound of the “likely range” (approximately 17% probability of exceedance) and “medium-high” represents a 1-in-200 chance (0.5% probability of exceedance). The extreme risk aversion (or H++) is a single scenario that does not have an associated likelihood of occurrence but is considered a high-end scenario associated with catastrophic melting of the West Antarctic Ice Sheet (OPC 2018).

Figure 27 presents a graphical plot of the sea-level rise projections for the Arena Cove tide station through the year 2100. Note that the curves accelerate over time, and that sea-level rise is expected to continue well beyond the end of the century. The OPC provides projections up to the year 2150; however, the uncertainty increases for projections beyond the year 2100 due to a limited number of models that project sea-level rise beyond the end of the 21st century.

SOURCE: data (OPC 2018) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 27
Sea-Level Projections for Arena Cove

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Due to the current uncertainty associated with models beyond the year 2100 as well as the likely removal of the extreme risk aversion scenario based on recent study (Sweet and others 2022), ESA applied the medium-high risk aversion projections from OPC’s 2018 guidance up to the year 2100 for this study: The corresponding amounts of sea-level rise used are 1.8, 3.3, and 6.7 feet for 2050, 2070 and 2100, respectively. Note that lower-cost facilities that are not as sensitive to coastal hazards or have greater adaptive capacity may be evaluated relative to the low-risk aversion curve: For example, it may not be desirable or practicable to locate a coastal trail or picnic table or lawn above and landward of the higher sea level projections but rather to relocate or reconstruct these features as needed.

4.3 Future Hazard Mapping
ESA considered several existing hazard models in addition to performing its own analysis. The results for potential future flood and erosion hazards are shown separately below. Though the results are separated by hazard type below, it is important to remember that flooding and erosion are intricately connected and that the actual future flood and erosion extents may be more or less than what is noted below. Similarly, combined fluvial and marine flooding may lead to exacerbated flood conditions if or when extreme marine and fluvial events occur simultaneously.

The following sections describe our assessment of how sea-level rise and climate change affects coastal flooding, fluvial flooding, combined coastal-fluvial flooding, and coastal erosion. We also reviewed available groundwater maps developed by USGS as part of the CoSMoS data and found that most of the area is currently mapped as very shallow to emergent groundwater, and with sealevel rise the groundwater designations do not change significantly. Therefore, groundwater is not considered a primary driver of vulnerability at the site, although any underground utilities could potentially be exposed to greater buoyancy forces. More detailed assessment of groundwater would require additional study beyond the scope of this study.

4.3.1 Future Coastal Flooding
The primary existing model for future coastal inundation with sea-level rise is the USGS’s CoSMoS (Barnard 2019). The model predicts future coastal flooding under a range of sea-level rise (0ft to 16.4ft) and storm scenarios (0-year to 100-year). Figure 28 below shows the results from CoSMoS for 0ft, 1.6ft, 3.3ft, and 6.6ft of sea-level rise with a 100-year storm. Note that CoSMoS does not model the exact amounts of sea-level rise that are prescribed by OPC; however, these scenarios shown below are approximate to those listed for the OPC medium-high risk sea-level rise projections. As Figure 28 depicts, the majority of the project area is inundated under present conditions, and flooding continues to move further up the valley with increasing sea levels.

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SOURCE: USGS CoSMoS, Point Blue City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 28
Future Inundation for a 100-year Storm with 0 to 6.6 Feet of Sea-Level Rise Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove 38 ESA / D202201148.00 Technical Report May 2025
While the CoSMoS results provides a reasonable assessment of future hazards at a broader scale, it is not intended for site specific analysis and does not provide a great level of detail when it comes to potential future flood depths. As such, ESA performed its own analysis of the potential future total water levels with future sea-level rise (see Figure 29). Based on ESA’s analysis, future extreme flooding (i.e., the 100-year flood) may be expected to increase by approximately 14 feet (e.g., from +33 to +47 feet NAVD) with up to 6.7 feet of sea-level rise by the end of the century. The curves in Figure 29 also indicate how the likelihood of an extreme event changes sea-level rise. For example, sea-level rise of less than 2 feet reduces the likelihood of the existing 100-year TWL to an approximately 9-year event. With additional sea level rise of 6.7 feet the likelihood decreases to an approximately annual event. These estimated likelihoods of TWL can be used as a measure of the effectiveness of the existing coastal structures at managing flooding.

As shown in Figure 29, the existing seawall currently provides a marginal level of protection, which is expected to reduce dramatically with sea-level rise. Additional study would be needed to refine the assessment of the implications on harbor functions and infrastructure useful life.

City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 29
Total Water Level Return Period for Present and Future
Conditions with Sea-Level Rise
To map the potential future flood zone in the Cove with sea-level rise, ESA assumed a Bruun shoreline transgression (i.e., that the shoreline will shift inland and upwards with sea-level rise, see section 4.3.4). While ESA notes that armoring is present within the Cove and may be maintained/upgraded to adjust with sea-level rise, using a Bruun shoreline transgression allows for a more conservative estimate of potential future flooding under more natural shoreline conditions, which may be a good indicator after failure of the armoring. An additional setback of 10 feet was also applied to the mapping extents as an adjustment associated with the removal of armor and/or the existing beach width, which provides a conservatively high estimate of extents.

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Figure 30 depicts the results of this mapping, where the future flood line indicates a potential future beach crest (if no armoring were present). As Figure 30 depicts, much of the Cove is already within the 100-year flood hazard zone. Given the topography of the Cove (i.e., a valley surrounded by steep bluffs), future flooding is restrained to the most low-lying areas. This means that as the sea level rises, flooding will simply move up the valley, deepening the existing flood levels and allowing for high velocity areas to move further inland as well.

SOURCE: Imagery (NOAA NGS
2023)
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 30
Existing and Future Coastal Flood Hazard Zones
Figure 31 presents graphics from CoSMoS modeling of the inundation with “non-storm” conditions, or flooding that may occur during typical wave and tide conditions, for existing and future conditions with sea-level rise up to 6.7 feet. The mapping shows that the flooding is focused on areas in vicinity of the creek mouth and the lower parking area just north of the creek, which is also vulnerable during storms. The area shown in the maps expands significantly when sea-level rise increases beyond 3.3 feet.

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SOURCE: USGS CoSMoS, Point Blue City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 31
Future Inundation for non-storm conditions with 0 to 6.6 Feet of Sea-Level Rise

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4.3.2 Future Fluvial Flooding
Future climate conditions scenarios were analyzed for design events with projected changes in extreme rainfall for a high emissions trajectory (RCP 8.5) for time horizons 2050 (2035- 2064), 2070 (2055-2084), and 2100 (2070-2100). Future extreme rainfall was quantified by performing a frequency analysis assuming a generalized extreme value distribution using 30 years of downscaled climate model projections centered around the future years of interest (CMIP5, 2013).

The increase in design event rainfall, averaged over the watershed, is summarized in Table 6.

The relative percent increase in extreme rainfall was used to scale the design event rainfall depths in the hydrologic model to derive peak flow values, which were then routed in the hydraulic model for each scenario shown in Table 6. Figure 32 shows the simulated flow hydrographs for design events under future climate conditions. In general, for a given flood return period, the peak flow rate increases over time.

TABLE 6. WATERSHED AVERAGE PERCENT CHANGE IN FUTURE EXTREME RAINFALL Emission
Scenario
Time
horizon
Recurrence
Interval
% Change relative to historic
period (1950-2005)
Model mean Model range
High (RCP 8.5) 2050
2-year 11.5% -0.1% - 55.9%
10-year 10.4% -0.1% - 30.3%
100-year 7.5% -17.4% - 42.1%
High (RCP 8.5) 2070
2-year 14.7% -11.1% - 55.1%
10-year 15.2% -0.1% - 36.8%
100-year 14.2% -18.0% - 43.8%
High (RCP 8.5) 2100
2-year 19.0% -0.1% - 49.9%
10-year 19.9% -11.3% - 46.8%
100-year 20.3% -17.3% - 70.4%

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City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 32
Predicted Peak Flows (cfs) in the Point Arena Watershed Under Future Climate Conditions
Figure 33 maps the flood extents for the 2-, 10-, and 100-year storms, comparing the existing conditions to those predicted for the 2100 time horizon. As the figures depict, the area of potential future flooding does not significantly increase between the existing and future conditions, but rather, the depth of flooding increases (e.g., the darker blue color indicating greater flood depth).

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SOURCE: Imagery (Maxar) City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 32
Existing and Future Fluvial Flooding Extent and Depths for the 2-, 10-, and 100-year Storm Events

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4.3.3 Combined Coastal and Fluvial Flooding
The wave and creek flood maps are plotted together on the same map in Figure 34. Similarly to the modeled creek flooding, the extent of the combined coastal-fluvial flood inundation does not significantly increase with sea-level rise and increased precipitation. This is largely due to the steep topography of the Cove area, which channels the overtopped coastal flooding as well as flooding from the creek into the roadway. Instead, it is anticipated that the flood depths and velocities will increase with climate change.

Note that where the wave and creek flood maps are overlain, an increase in the 100-year water level is implied. Quantifying this increase is beyond the scope of this study but may be worthwhile if more detailed mapping is accomplished. Note that this map indicates more severe flooding than the effective FEMA map (Figure 19).

SOURCE: Imagery (NOAA
NGS 2023)
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 34
Combined Coastal-Fluvial Flooding for a 100-year Storm:

Existing and Future Conditions with 6.7ft of Sea-Level Rise

4. Future Conditions with Sea-Level Rise
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4.3.4 Future Erosion
Shoreline Evolution with Sea-Level Rise
Future sea-level rise is expected to create a permanent rise in ocean water levels that will shift the water’s edge landward. Higher water levels will result in larger waves that break closer to the shoreline and higher wave runup. In general, the higher water levels and associated waves are expected to increase beach and bluff erosion and result in narrower beaches depending on sand supply. That said, beaches and bluffs will likely respond to sea-level rise differently. A rise in sea levels will likely cause beach systems to shift landward and upward, as the waves erode the shore and sediment deposits in the surf zone, essentially rebuilding the surf zone sea floor at the higher sea level10 (see Figure 35). This may erode, modify, or cover City assets, depending on proximity to the shoreline and height above sea level.

This migrating shore condition will not occur in all locations. For example, areas with erosion resistant barriers (like seawalls and the bluffs at Point Arena) will not erode fast enough to provide space for beaches but rather may supply beach material that will migrate offshore or along shore to other beaches: The cove area of Point Arena may accumulate cobble and other sediments over time, depending on the backshore conditions.

Increased sediment loads from the rivers (i.e., if rainfall frequency or intensity increases) or localized erosion of bluffs; however, depending on amount of sea-level rise, the characteristics of the backshore (e.g., armored or natural), and the soil composition, these sediment delivery processes may or may not be enough to keep pace with projected rising seas. In general, allowing shores to migrate landward and up with sea level rise is most likely to extend the life of these features. Indeed, this constructive response to sea level rise (aka resilience) is one reason that Natural Shore Infrastructure is gaining State11 and Federal12 interest. 10 This process of shore ‘transgression’ is often referred to as the ‘Bruun Rule’ owing to the geometric shore response conceptual model developed by Brunn (1962)
11 ‘CA Gov’t Code Chapter 3 ARTICLE 5. Authority for and Scope of General Plans 65302. (g)(4)(C)(v) The identification of natural infrastructure that may be used in adaptation projects, where feasible. Where feasible, the plan shall use existing natural features and ecosystem processes, or the restoration of natural features and ecosystem processes, when developing alternatives for consideration. For purposes of this clause, “natural infrastructure” means using natural ecological systems or processes to reduce vulnerability to climate change related hazards, or other related climate change effects, while increasing the long-term adaptive capacity of coastal and inland areas by perpetuating or restoring ecosystem services. This includes, but is not limited to, the conservation, preservation, or sustainable management of any form of aquatic or terrestrial vegetated open space, such as beaches, dunes, tidal marshes, reefs, seagrass, parks, rain gardens, and urban tree canopies. It also includes systems and practices that use or mimic natural processes, such as permeable pavements, bioswales, and other engineered systems, such as levees that are combined with restored natural systems, to provide clean water, conserve ecosystem values and functions, and provide a wide array of benefits to people and wildlife.’ 12 US Army Corps of Engineers, Engineering Research and Development Center Engineering With Nature (EWN) https://ewn.erdc.dren.mil/wp-content/uploads/2021/04/ASBPA-1130-1150_Natural_Infrastructure_Altman.pdf

4. Future Conditions with Sea-Level Rise
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City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 35
Cobble Berm Profile Evolution with Sea-Level Rise
Future Erosion Hazard Zones
There are a number of acceptable methods for predicting future erosion; however, the unique geomorphology of the Cove does not lend itself to a specific one. Most methods rely upon historic erosion rates and then amplify the historic rate by a certain percentage to account for accelerated erosion with sea-level rise. In the case of the Cove, the dual geomorphologies (i.e., bluff and beach), ESA reviewed several existing models that project future erosion hazard zones that are also readily available or applicable within the parameters of this study13.

Figure 36 shows bluff erosion forecast by the Pacific Institute team (PWA (formerly ESA) 2009) as well as USGS’ CoSMoS modeling for the bluffs on both sides of the developed Arena Cove.

Because the Pacific Institute and USGS models focus on bluff erosion, ESA performed an analysis of potential shoreline erosion within the Cove itself (Figure 37). ESA’s analysis considered erosion of the existing shoreline (including the armored shoreline as it is presently located as well as the cobble berm seaward of the lagoon). A basic Bruun transformation14, which presumes the shore migrates up and landward in proportion to sea level rise and the overall slope of the surf zone (e.g., Figure 35), to model potential future erosion within the Cove. 13 ESA has developed methods to address shore response to sea level rise etcetera for a range of conditions but the application of these models is beyond the scope of this project. These models are particularly useful when evaluating alternative adaptation plans which may include a range of strategies such as armoring, beach nourishment and retreat.
14 This process of shore ‘transgression’ is often referred to as the ‘Bruun Rule’ owing to the geometric shore response conceptual model developed by Brunn (1962).

4. Future Conditions with Sea-Level Rise
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SOURCE: USGS (CoSMoS) and
PWA 2009; Imagery
(Maxar)
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 36
Potential Erosion Hazard Zones with Sea-Level Rise

4. Future Conditions with Sea-Level Rise
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In general, we expect that unarmored shore would move landward with sea-level rise along with the adjacent bluffs. A more detailed analysis is needed to provide erosion projections than can be accomplished with the scope of this study.

SOURCE: USGS (CoSMoS); Imagery (NOAA NGS
2023)
City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 37
Potential Shoreline Erosion with Sea-Level Rise
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5. VULNERABILITY ASSESSMENT
Vulnerability may be defined as “the degree to which natural, built, and human systems are at risk of exposure to climate change impacts…”.15 As the definition implies, vulnerability is a function of a resource’s exposure, sensitivity, and adaptive capacity to a given hazard or stressor. This section provides an overview of the vulnerability analysis methodology as well as a summary of the City’s assets that are vulnerable to the coastal hazards identified in section 4.

5.1 Methodology
Assets within the study area (see Figure 2) were analyzed to determine their potential exposure to the flooding and erosion hazards as well as the sensitivity and adaptive capacity of the assets to the potential hazard. Sensitivity and adaptive capacity scoring were developed based on ESA’s judgement and with input from the City and community members. The results of this analysis are summarized in Table 10.

5.1.1 Exposure to Hazard
To assess exposure to hazards, the ESA compared an asset’s proximity to the erosion and inundation areas noted in section 4. For flood hazards, ESA evaluated an asset’s proximity to the combined fluvial and marine 100-year flood zone (section 4.3.3) as well as the freeboard (i.e., elevation) above or below the floodplain. For the erosion hazards, ESA evaluated an asset’s proximity to potential future shorelines, assuming no armoring is present. Armoring was not included in the erosion hazard mapping in an effort to conservatively evaluate future vulnerabilities. We expect that armoring may continue to be used in the future, however modifications, including both elevation or location, would be needed to manage flooding as sealevel rise increases and flooding extents expand landward.

A hazard exposure grade of Low, Medium, or High (Table 7) was assigned to characterize each asset’s exposure to hazards. This grade was assigned after quantifying the asset’s exposure and is dependent on both timeframe (e.g., if an asset could potentially flood in the near-term it would have a higher hazard exposure grade than one that could flood in the long-term) and the potential level of severity posed by the type of hazard zone (i.e., erosion versus long-term effects of infrequent flooding). For example, future erosion by 2050 is considered “high” exposure because it would cause significant damage to structures and infrastructure in the near-term, while exposure to erosion in 2070 is considered “medium” exposure and erosion by 2100 is considered “low” exposure because the risk is later in the century. Exposure to 100-year flooding by 2050 is considered “medium” exposure because while the risk is a near-term risk, it is still a lowlikelihood event (i.e., 1% annual chance of occurrence annually). 15 California Governor’s Office of Planning and Research (OPR), 2018. Defining Vulnerable Communities in the Context of Climate Adaptation. Las accessed March 8, 2023 via https://opr.ca.gov/docs/20180723-Vulnerable_ Communities.pdf.

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TABLE 7. HAZARD EXPOSURE SCORING
Timeframe
Anticipated Amount of Sea-Level
Rise (ft) Under CCC/OPC
Medium-High Risk Scenario Future Erosion
Future 100-year Combined
Coastal-Fluvial Flooding
Existing 0 High High
Short-term (2050) 1.8 High Medium
Mid-term (2070) 3.3 Medium Low
Long-term (2100) 6.7 Low Low

5.1.2 Sensitivity to Hazard and Adaptive Capacity
Sensitivity is an asset’s level of impairment when flooded or affected by erosion or waves. In general, assets that are highly sensitive would lose their primary function if exposed to any degree of flood or erosion whatsoever. If assets can maintain their primary function(s) during inundation, they would have low sensitivity. If assets would lose only part of their function, it is considered, for the purposes of this assessment, moderately sensitive. For example, one of the sensitivities of impacts to roadways is the disruption of vehicular access critical for the provision of emergency services, which would mean the asset has a high sensitivity.

Similar to the hazard exposure scores, a hazard sensitivity grade is determined for each asset.

Table 8 presents the grading scheme.

TABLE 8. HAZARD SENSITIVITY SCORING
Score Considerations
Low The given hazard would have no or a low impact on the asset, and the primary function of the asset could be maintained.

Medium The given hazard would cause minor damage or disruption.

High The given hazard would cause major damage or disruption.

For the purposes of this study, adaptive capacity is defined as the asset’s ability to cope with and recover from impacts. In general, assets that have low adaptive capacity would take a long time or be unable to recover if exposed to any degree of flood or erosion whatsoever. If assets are operational as soon as water recedes, they would have high adaptive capacity. For example, in many cases once waters recede off parking lots, vehicular access is restored with little damage to the roadway itself, which would mean the asset has a high adaptive capacity. Note, adaptive capacity is inversely correlated with vulnerability (i.e., low adaptive capacity leads to higher vulnerability). Table 9 presents the adaptive capacity scoring scheme.

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TABLE 9. HAZARD ADAPTIVE CAPACITY SCORING
Score Considerations
High The asset would be able to rebound from the impact quickly (e.g., high adaptive capacity).

Medium The given hazard would cause temporary operational interruption.

Low The given hazard would cause long-term operational interruption. The asset would require a significant effort to rebound from the impact (e.g., low adaptive capacity).

5.1.3 Overall Vulnerability
The overall vulnerability for each asset was determined based on the combination of an asset’s vulnerability components (Figure 38):

Vulnerability = (Exposure + Sensitivity) – Adaptive Capacity The vulnerability summaries are indications of the degree of potential vulnerability, not rankings or priorities.

SOURCE: ESA 2023 City of Point Arena Sea-Level Rise Vulnerability Assessment Figure 38
Components of Vulnerability

5.2 Point Arena Cove Vulnerabilities
Table 10 below presents the results of the vulnerability analysis for the assets that were noted in section 2.3. Note that for the purposes of this study, the individual pier assets have been grouped together and placed under the general “developed areas” asset category.

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TABLE 10. ARENA COVE ASSET VULNERABILITIES
Asset Hazard Exposure
Timeframe
Exposure
Score Consequences of Exposure Sensitivity Score
Adaptive
Capacity Score
Overall
Vulnerability
Shoreline Armoring
Revetment Present High Overtopping and more frequent interaction with larger waves may degrade the existing structure.

Medium Medium Medium
Seawall Present High Overtopping and more frequent interaction with larger waves may degrade the existing structure
Medium Medium Medium-High
Developed Areas
Pier Present High Higher sea levels decrease the negative freeboard, allowing larger waves to more frequently batter the structure and potentially reach the decking or degrade the stability of the pilings and attached equipment.

High Low High
Parking lot Present High Parking and access (including for emergency purposes) will be temporarily cutoff until inundation recedes. Erosion of the cobble berm and lagoon area may cause more extensive
inundation of the parking lot during large storm events as the lagoon area moves further landward.

Medium Medium Medium-High
Event/overflow
parking
2070 Medium Increased coastal and fluvial flooding may render the overflow parking lot unusable during extreme events in the mid- to longterm.

Low Medium Low-Medium
Historic Coast Guard
Boathouse
Present High According to community observations, the CG building has historically experienced inundation during large storm events.

Larger waves and higher future sea levels will likely undermine the building foundation and cause direct structural damage, rendering the building unusable and a potential hazard to landward buildings if waves relocate portions of the structure further inland.

High Low High
Private Property Present High According to community observations, the lower buildings within the Cove frequently experience flooding at present. Larger waves and higher future sea levels will increase the frequency and extent to which inundation is experienced. This may cause more frequent closures and the need for repairs or floodproofing for buildings to remain inhabitable and operable.

High Medium Medium-High
Utilities
Electric Present High Electric utilities (especially those located belowground) will experience more frequent inundation from sea-, creek-, and groundwater-rise. Power (potentially supporting
communications and emergency services) may be cut off during storm events. High winds in January 2023 downed power lines resulting in an inability to operate the boat lift, raise the floating dock, maintain power to the sewer lift station, and more.

High Medium Medium-High

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TABLE 10. ARENA COVE ASSET VULNERABILITIES
Asset Hazard Exposure
Timeframe
Exposure
Score Consequences of Exposure Sensitivity Score
Adaptive
Capacity Score
Overall
Vulnerability
Sewer pump station Present High If inundated, the sewer pump station may become inoperable, causing the system to back up or spill over. Inoperable during power outages.

High Medium Medium-High
Sewer manholes Present High Sewer manholes may not be able to convey waste, causing the system to back up or spill over.

High Low High
Recreational
Picnic area / Park 2050 High Erosion of the fronting bluff may undermine the picnic area. Low High Low-Medium Beaches Present High Erosion and more frequently flooding of the beaches will decrease both the space and duration over which beachgoers can effectively enjoy the area. The existing armoring may cause additional squeezing16 of the shoreline.

Medium Medium Medium-High
Surfing Present Low Although higher water levels may allow for bigger waves to travel closer to shore, the “reef breaks” are best during low to mid tide levels could break less frequently with higher water levels. SLR may increase wave reflection off of the bluffs, which will change the quality of the surf breaks.

Low Medium Low-Medium
Ecological
Beaver habitat Present High Higher sea levels (and therefore saline water) may intrude further inland with sea-level rise. Larger and more extreme events may cause more intense flooding of the lagoon and creek systems, potentially altering the suitability of the habitat for the Point Arena mountain beaver.

Medium Medium Medium-High
Wetland habitat Present High Higher sea levels (and therefore saline water) may intrude further inland and more frequently with sea-level rise. With adequate space to migrate inland, wetland habitats may be able to recover. Without adequate migration space, wetland habitats will eventually be squeezed out.

High Medium Medium-High
Bioretention basin Present High More frequent and larger overtopping from coastal and fluvial flooding may damage the retention structure and prevent it from naturally recovering without anthropogenic interference.

Medium Medium Medium-High
16 With ongoing beach erosion and sea-level rise and without any other mitigating measures, fixing the shoreline location with a seawall or revetment will eventually lead to the loss of the beach seaward of the structure(s).

5. Vulnerability Assessment
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6. REFERENCES
Barnard, P.L., Erikson, L.H., Foxgrover, A.C., Finzi Hart, J.A., Limber, P., O’Neill, A.C., van Ormondt, M., Vitousek, S., Wood, N., Hayden, M.K., and Jones, J.M., 2019. Dynamic flood modeling essential to assess the coastal impacts of climate change. Scientific Reports, Volume 9, Article #4309, 13 pp., http://dx.doi.org/10.1038/s41598-019-40742-z.

Behrens, D.K., Brennan, M., Battalio, B., 2015, A quantified conceptual model of inlet morphology and associated lagoon hydrology, Shore and Beach, 83(3), pp. 33-42.

California Coastal Commission (CCC), 2018, Sea-level Rise Policy Guidance: Interpretive Guidelines for Addressing Sea-level Rise in Local Coastal Programs and Coastal Development Permits, adopted on August 12, 2015; update adopted November 7, 2018.

Cayan et. al., 2009. Cayan, D., Tyree, M., Dettinger, M., Hidalgo, H., Das, T., Maurer, E., Bromirski, P., Graham, N., and Flick, R., 2009, Climate Change Scenarios and Sea Level Rise Estimates for California 2008 Climate.

CMIP5. 2013. Downscaled CMIP3 and CMIP5 Climate Projections: Release of Downscaled CMIP5 Climate Projections, Comparison with Preceding Information, and Summary of User Needs. U.S. Department of the Interior, Bureau of Reclamation, Technical Service Center, Denver Coorado, 116 p., available at: https://gdo-dcp.ucllnl.org/downscaled_ cmip_projections/dcpInterface.html#About.

FEMA, 2014, Intermediate Data Submittal #3: Nearshore Hydraulics, Mendocino County, California, FEMA Region IX, California Coastal Analysis and Mapping Project / Open Pacific Coast Study, Prepared by BakerAECOM, August 2014.

Griggs, G., Árvai, J., Cayan, D., DeConto, R., Fox, J., Fricker, H.A., Kopp, R.E., Tebaldi, C., Whiteman, E.A. (California Ocean Protection Council Science Advisory Team Working Group), 2017, Rising Seas in California: An Update on Sea-Level Rise Science, California Ocean Science Trust, April 2017.

Hapke et. al. 2006. National Assessment of Shoreline Change, Part 3: Historical Shoreline Change and Associated Coastal Land Loss Along Sandy Shorelines of the California Coast.

U.S. Geological Survey Open-File Report 2007-1219. Last accessed on March 3, 2023 via https://pubs.usgs.gov/of/2006/1219/of2006-1219.pdf.

Hapke, C.J. and Reid, D. 2007. National Assessment of Shoreline Change, Part 4: Historical Coastal Cliff Retreat along the California Coast. U.S. Geological Survey Open-File Report 2007-1219Last accessed on March 3, 2023 via https://pubs.usgs.gov/of/2007/1133/of2007- 1133.pdf.

6. References
Sea-Level Rise Analysis and Vulnerability Assessment for Point Arena Cove 56 ESA / D202201148.00 Technical Report May 2025
OCM Partners, 2023: 2017 FEMA Lidar: California Region 9, https://www.fisheries.noaa.gov/inport/item/58428.

Ocean Protection Council (OPC), 2018, State of California Sea-Level Rise Guidance, prepared by the California Natural Resources Agency and the California Ocean Protection Council, adopted March 14, 2018.

Ocean Protection Council (OPC), 2020, Strategic Plan to Protect California’s Coast and Ocean 2020-2025, prepared by the California Natural Resources Agency and the California Ocean Protection Council, adopted February 26, 2020.

Ocean Protection Council (OPC), 2024. State of California Sea Level Rise Guidance: 2024 Science and Policy Update. Prepared by California Sea Level Rise Science Task Force, California Ocean Protection Council, California Ocean Science Trust. Accessed online:
https://opc.ca.gov/wp-content/uploads/2024/05/California-Sea-Level-Rise-Guidance-2024- 508.pdf.

Philip Williams & Associates, Ltd. (PWA), 2009. California Coastal Erosion Response to Sea Level Rise Analysis and Mapping. Prepared for the Pacific Institute. March 11, 2009. PWA REF. #1939.00.

Shope, James B.; Erikson, Li H.; Barnard, Patrick L.; Storlazzi, Curt D.; Serafin, Katherine; Doran, Kara; Stockdon, Hilary; Reguero, Borja; Mendez, Fernando; Castanedo, Sonia; Cid, Alba; Cagigal, Laura; Ruggiero, Peter (2022). “Characterizing storm-induced coastal change hazards along the United States West Coast.” Scientific Data. Vol. 9, Issue 224. http://doi.org/10.1038/s41597-022-01313-6.

U.S. Fish and Wildlife Service (USFWS), 1998, Point Arena Mountain Beaver (Aplodiontia rufa nigra (Rafinesque)) Recovery Plan, Region 1, Portland, Oregon, 71 pp. Accessed online September 18, 2023: https://ecos.fws.gov/docs/recovery_plan/980602.pdf.

U.S. Fish and Wildlife Service (USFWS), 2023, Endangered and Threatened Wildlife and Plants; Initiation of 5-Year Status Reviews of 47 Species in California, Nevada, and Oregon, Notice of initiation of reviews; request for information, Department of the Interior, Fish and Wildlife Service, Federal Register, Vol. 88, No. 158, August 17, 2023. Accessed online September 18, 2023: https://www.govinfo.gov/content/pkg/FR-2023-08-17/pdf/ 2023-17728.pdf#page=1.

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7. LIST OF PREPARERS
The following ESA staff contributed to the work described in this report:

Louis White, PE
Bob Battalio, PE
Meagan Flier, EIT
Yashar Rafati, PhD, PE
Phong Ly, EIT
James Gregory, PE
ESA also acknowledges the review and guidance of the City of Point Arena staff, including Scott Perkins and Paul Andersen, City Council members, and the Point Arena community members during site visits, meetings, and workshops.

7. List of Preparers
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CITY OF POINT ARENA
451 School Street
P.O. Box 67
Point Arena CA 95468
(707) 882-2122
pointarena.ca.gov
Mayor Anna Dobbins
Vice-Mayor Dan Doyle
Councilmember Barbara Burkey
Councilmember Jim Koogle
Councilmember Jeff Hansen
Molly Haviland, City Manager

NOTICE OF A PUBLIC HEARING FOR THE PROPOSED GENERAL PLAN/LOCAL COASTAL PROGRAM AMENDMENT GP # 2025-01
NOTICE IS HEREBY GIVEN that the Point Arena City Council will conduct a public hearing in-person and via teleconference (https://zoom.us/j/92924523393) on Tuesday, November 18, 2025 at 6:00 p.m., or as soon thereafter as possible, on the following:

General Plan/Local Coastal Program Amendment
Public Hearing will be held Approving/Denying the Following Project:

CASE: GP # 2025-01
DATE FILED: October 16, 2025
APPLICANT: City of Point Arena
REQUEST: Review and consider a recommendation to the City Council of an amendment of the City of Point Arena Local Coastal Program General Plan. GP #2025-01 proposes to incorporate sea level rise into the Community Safety & Health Element.

LOCATION: Within the City of Point Arena boundaries. The entirety of the City of Point Arena is within the Coastal Zone.

PUBLIC HEARING DATE: November 18, 2025
ENVIRONMENTAL DETERMINATION: Statutory Exemption pursuant to Public Resources Code §15061.b.3 the common sense categorical exemption.

The Point Arena City Council is soliciting your input. All interested parties are invited to attend and be heard at this time. Applicants or their agents must appear for their hearings. If you challenge the above matter(s) in court, you may be limited to raising only those issues you or someone else raised at the public hearing described in this notice, or in written correspondence delivered to the City Clerk at, or prior to, the public hearing. All documents are available for review in the City Clerk’s Office. The City Council’s action regarding the item shall constitute final action by the City unless appealed to the Coastal Commission. Appeals to the Coastal Commission must be made in writing within 10 working days following Coastal Commission receipt of a Notice of Final Action on this project. Should you desire to request notification of the City Council’s decision you may do so in writing by providing a self-addressed stamped envelope to the City Clerk.

For further information contact the City of Point Arena:

Mailing Address: PO Box 67, Point Arena, California 95468 City Hall Location: 451 School Street, Point Arena, California 95468 Telephone: 707 882-2122
Website: https://pointarena.ca.gov
Email: [email protected]
/Paul Andersen
City Clerk
Date: November 7, 2025

Point Arena City CouncilDecember 16, 2025

Point Arena City Council
December 16, 2025