2026-08-14; South Carlsbad Boulevard Shoreline Protections Update (District 3); Gomez, Paz

To the members of the:

CITY COUNCIL
Date tl\1~ CA _k:'.' CC ✓
CM ~AC ✓ DCM (3) V"
August 14, 2026
Council Memorandum
To:

From:

Honorable Mayor Blackburn and Members of the City Council Paz Gomez, Deputy City Manager, Public Works
Sheila Cobian, Assistant City Manager~ Via:

Re: South Carlsbad Boulevard Shoreline Protections Update (District 3) {city of
Carlsbad
Memo ID# 2026042
This memorandum provides background on the city's request to the California Coastal Commission (CCC) to administratively extend the expiration date of its Coastal Development Permit (CDP), the Surfrider Foundation's opposition to that request, and the actions taken in response. The city's CDP authorized temporary shoreline protection along South Carlsbad Boulevard near Las Encinas Creek to protect the roadway from potential collapse during severe storm events.

Background
In December 2015, severe El Nino storms and
extreme high tides battered the Southern
California coast, causing major erosion along
south Carlsbad Boulevard near Las Encinas
Creek (Attachment A). High surf caused by the
storms resulted in significant erosion that
threatened collapse of the roadway,
prompting the city to declare a local State of
Emergency. The CCC issued the city an
Emergency Coastal Development Permit
(ECDP) on December 29, 2015, authorizing the
temporary installation of heavy boulders on
the beach. This 270-foot-long rock
"revetment" has helped protect the roadway from collapse over the years.

The purpose of an ECDP is to allow a public agency to immediately respond to an emergency that poses an imminent danger to life and/or public property. Once the threat has passed, however, a regular Coastal Development Permit (CDP) is required to implement permanent solutions that meet the requirements set forth in the California Coastal Act.

In March 2018, the CCC approved a regular CDP granting follow-up approval to temporarily retain the 270-foot revetment and after-the-fact approval of an additional 250-foot segment that was installed in 2016, for a total of five years. As part of the CDP, certain conditions were included that required the city to analyze and evaluate alternatives to shoreline protection as well as an implementation plan and funding strategy for CCC consideration and approval. The due date given to the city to complete these conditions was March 14, 2023.

Public Works Branch
Transportation Department
1635 Faraday Avenue I Carlsbad, CA 92008 I 442-339-2730 t Council Memo -South Carlsbad Boulevard Shoreline Protections Update (District 3) August 14, 2026

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Since work was still being done to satisfy the conditions of the CDP, the city requested and the CCC granted a one-year extension to March 14, 2024. This extension was determined by the CCC Executive Director to be immaterial1 or otherwise minor and administrative in scope and scale pursuant to the California Coastal Act.

As work on the conditions continued, more time was needed and the city requested to extend the due date to March 14, 2031. It was the intention of the CCC Director to approve this request as immaterial, like the previous extension (Attachment B). However, the Surfrider Foundation submitted a letter to the CCC on July 3, 2026, objecting to the immaterial processing of the time extension request (Attachment C). Following receipt of this letter, six Commissioners objected to the Executive Director's designation of immateriality, so pursuant to the California Coastal Act, the request must now be considered by the full California Commission at a future hearing date, which is anticipated to be October 2026.

Discussion
The Surfrider letter makes several assertions, but much of its focus is on the status of two Coastal Development Permit (CDP) conditions -Conditions lb and le -which are included on page 3 of Attachment B.

In summary, Condition lb requires the city to apply for a regular CDP to prepare a "Long-Term Hazards Management Plan." The plan is intended to identify measures to address current and future coastal hazards at the site. Condition le requires that, if the city intends to retain the revetment beyond the permit period -as it does -the permit application must evaluate alternatives to the revetment and include mitigation for its effects on public access, recreation, and other coastal resources during its remaining expected life. Surfrider contends that the city has failed to prepare the documents required by these conditions.

That is not accurate.

The city's Long-Term Hazards Management Plan, titled the "South Carlsbad Climate Adaptation Project-Long-Term Master Plan/Adaptive Management Plan" (Attachment D), was presented to the City Council on April 23, 2024. The plan was also provided to CCC staff for review. In a letter to the city (Attachment E), CCC staff identified corrections and omissions that need to be addressed before the plan fully satisfies Condition lb. City staff have been actively working to address those comments; however, additional time is needed due to other priorities and emergency events.

For example, in early 2024, two emergencies occurred -one at the Buena Vista Channel and another on El Camino Real between Chestnut Avenue and Tamarack Avenue -that resulted in the City Manager declaring local emergencies. These events required significant staff resources and shifted priorities. Barring any new emergencies, staff anticipate presenting the revised management plan to the City Council in fall 2027.
1 An immaterial finding allows for a streamlined {administrative) process for making minor, non-controversial changes to a previously approved coastal development permit as issued by the CCC. These are typically classified under Section 13166{b) of Title 14 of the California Code of Regulations. Also under Section 13166, the proposed amendment does not present the potential for adverse impacts, individually or cumulatively, on coastal resources or public access.

Council Memo -South Carlsbad Boulevard Shoreline Protections Update (District 3) August 14, 2026

Page 3 ends

The "Final Alternatives Analysis Report -Las Encinas Revetment," dated May 2017 (Attachment F), was prepared to address Condition le. The report was submitted with the CDP application in 2018 and was provided again to CCC staff in February 2026. Given the time that has passed since the report was prepared, and because the city intends to retain the revetment until a long-term solution is developed and implemented, the city plans to update the report and present it to the City Council in fall 2027.

The Surfrider letter also alleges that the city lacks financial commitment to the project and no longer considers it a priority. This characterization is both misleading and inaccurate.

Surfrider is referring to the South Carlsbad Boulevard Coastline Project, a grant-funded effort to explore ways to improve accessibility along approximately three miles of South Carlsbad Boulevard.

Through funding from the California State Coastal Conservancy, the city developed a report evaluating how a one-mile segment of South Carlsbad Boulevard could be managed to protect people, the environment, and infrastructure from anticipated sea level rise. The report was presented to the City Council on April 23, 2024.

Because this is a grant-funded effort, the city has actively pursued additional funding and has applied for seven grants to further develop the project. None has been awarded to date. One grant application was submitted in June 2026, with results expected in September. The seventh grant is pending a full application, which staff anticipate submitting in September.

The project is a potential solution to the current road erosion issues and may be included as an option in the Long-Term Hazards Management Plan. However, the CDP conditions do not require the city to fund or construct this particular project. Condition lb requires only consideration of " ... potential phasing options with timelines, project costs for the preferred project and alternatives, and potential funding options." It does not require that a specific project be funded or constructed.

That said, the project is a City Council priority and is included in the city's Five-Year Strategic Plan for 2023-2027. In addition, the city has appropriated a total of $2 million in fiscal years 2024-25 and 2025-26 for continued conceptual planning and design of a roadway realignment away from the bluff as part of CIP Project No. 6113. This project is intended to address the revetment and shoreline protection as part of a long-term solution.

The Surfrider letter also states that wave action has begun cutting behind the northern end of the revetment. As required by the permit, city staff continue to monitor and survey the revetment and provide summary reports to the CCC every five years. The most recent report was submitted in April 2025, and the next report is scheduled for April 2030.

The April 2025 monitoring report found that the 4-ton and 2-ton rock revetment has generally performed well, with only a few rocks displaced. The report concluded that these conditions were not expected to threaten the integrity of the revetment, roadway, or bridge under normal weather conditions. Although storm-related erosion had lowered the beach elevation during the winter, similar conditions had occurred during previous inspections, and the beach was expected to recover during the spring and summer. Overall, the report concluded that the revetment was stable and expected to continue providing protection for years to come.

Council Memo -South Carlsbad Boulevard Shoreline Protections Update (District 3) August 14, 2026

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In preparation for the upcoming hearing on the permit extension, which is tentatively scheduled for October in Oceanside, city staff met with CCC staff to discuss follow-up questions, requested information, and the hearing process. The city provided the requested supporting information to CCC staff on August 14, 2026 (Attachment G).

Next Steps
Staff will continue to coordinate with CCC staff to prepare for the upcoming October CCC hearing on the CDP extension request.

Attachments:

A. Carlsbad Boulevard Revetment Location Map
B. Notice of Proposed Immaterial Permit Amendment dated June 24, 2026 C. Surfrider Foundation letter dated July 3, 2026
D. Draft Long-Term Hazards Management Plan
E. California Coastal Commission letter
F. Final Alternatives Analysis Report -Las Encinas Revetment G. Supporting Information to CCC Staff Report
cc: Geoff Patnoe, City Manager
Cindie McMahon, City Attorney
Jeff Murphy, Deputy City Manager, Community Services
Zach Korach, Deputy City Manager, Administrative Services Tim Lyons, Assistant City Attorney
Tom Frank, Transportation Director/City Engineer
Jason Haber, Intergovernmental Affairs Director
Kyle Lancaster, Parks & Recreation Director
Mike Strong, Community Development Director
Amy Ventetuolo, Communication & Engagement Director
Eric Lardy, Assistant Director of Community Development John Kim, City Traffic Engineer
Mariel Paras, Principal Engineer
Brandon Miles, Senior Engineer

LOCATION
SITE

OT TO SCALE
N

PROJECT NAME

PACIFIC
OCEAN
MAP

CARLSBAD BOULEVARD REVETMENT
Attachment A

PROJECT ATTACHMENT
NUMBER 8
6063

STATE OF CALIFORNIA-NATURAL RESOURCES AGENCY
Attachment B

GAVIN NEWSOM, GOVERNOR

CALIFORNIA COASTAL COMMISSION

SAN DIEGO COAST DISTRICT OFFICE
7575 METROPOLITAN DRIVE, SUITE 103
SAN DIEGO, CALIFORNIA 92108-4402
VOICE (619) 767-2370
WWW.COASTAL.CA.GOV
To:

From:

June 24, 2026

NOTICE OF PROPOSED IMMATERIAL PERMIT

AMENDMENT
Coastal Development Permit Amendment No. 6-16-0450-A2
All Interested Parties
Kate Huckelbridge, PhD, Executive Director
Subject: Permit No. 6-16-0450-A2 granted to City of Carlsbad for: Follow-up approval to retain a 270 linear foot rock revetment authorized by emergency permit for five years, and after-the-fact approval of construction of an additional 250 linear foot revetment on the beach protecting southbound lanes of Carlsbad Boulevard.

Project Site: West side of southbound Carlsbad Boulevard, north of Encinas Creek, Carlsbad, San Diego County
The Executive Director of the California Coastal Commission has reviewed a proposed amendment to the above referenced permit, which would result in the following change(s):

FINDINGS
Amend Special Condition 1 to extend authorization for seven additional years.

The Executive Director has determined this amendment to be IMMATERIAL within the meaning of section 13166(b) of the Commission's regulations.1 Pursuant to section 13166(b)(1 ), if no written objection to this notice of immaterial amendment is received at the Commission office listed above within ten (10) working days of mailing said notice, the determination of immateriality shall be conclusive, and the amendment shall be approved (i.e., the permit will be amended as proposed).

Pursuant to section 13166(b)(2), if a written objection to this notice of an immaterial amendment is received within ten (10) working days of mailing notice, and the executive director determines that the objection does not raise an issue of conformity with the Coastal Act or certified local coastal program if applicable, the amendment shall not be 1 The Commission's regulations are codified in Title 14 of the California Code of Regulations.

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June 24, 2026
Notice of Proposed Immaterial Permit Amendment
6-16-0450-A2
effective until the amendment and objection are reported to the Commission at its next regularly scheduled meeting. If any three Commissioners object to the executive director's designation of immateriality, the amendment application shall be referred to the Commission to be reviewed as a material amendment at a subsequent Commission meeting. If no three Commissioners object to the executive director's designation of immateriality, that designation shall stand, and the amendment shall become effective.

Pursuant to section 13166(b)(3), if a written objection to this notice of an immaterial amendment is received within ten (10) working days of mailing notice, and the executive director determines that the objection does raise an issue of conformity with the Coastal Act or a certified local coastal program if applicable, the amendment application shall be referred to the Commission to be reviewed as a material amendment at a subsequent Commission meeting.

The Executive Director has determined this proposed amendment to be "immaterial" for the following reason(s):

March 14, 2024). The revetment is located on the beach, seaward of southbound Carlsbad Boulevard, south of Palomar Airport Road and north of Encinas Creek.

The City has submitted this amendment request prior to the expiration of the authorization period, and the subject amendment does not undermine the intent of Special Condition 1, which was to ensure that the City actively seeks a longer term solution to erosion at the subject site. The deadline for auth.orization was intended to allow the City to develop a Hazards Management Plan, a portion of which was completed in February 2024 for the South Carlsbad Climate Adaptation project. The seven additional years will allow the City time to apply for new grant funding to move the project from feasibility and conceptual design to finalization of the roadway alignment and environmental restoration alternatives, as well as time to conduct a construction feasibility study, and complete the environmental documentation and permitting. No adverse impacts are anticipated, and thus the proposed project will not adversely impact coastal resources and can be found in conformance with Chapter 3 policies of the Coastal Act.

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June 24, 2026
Notice of Proposed Immaterial Permit Amendment
6-16-0450-A2
CDP 6-16-0450-A2 amends the following Special Condition approved by 6-16-0450 and 6-16-0450-A 1 :

1. Limited Authorization Period and Long-Term Hazard Management Plan. (a) This coastal development permit authorizes the shoreline protection for~ thirteen years from the date of this permit approval (i.e., to March 14, 2-G-24 2031) or until the time when the currently existing structures warranting armoring are no longer present or no longer require armoring for such protection, whichever occurs first.
(b) No later than~ thirteen years after the approval of this permit (i.e., by March 14, 2-G-24 2031 ), the permittee or successor in interest shall apply for a regular coastal development permit to implement a long-term Hazards Management Plan for Carlsbad Boulevard that addresses current and future coastal hazards present at the site. The Hazards Management Plan shall incorporate measures to adapt to sea level rise over time and provide for the long term protection and provision of public improvements, coastal access, public opportunities for coastal recreation, public views and coastal resources, including beach and shoreline habitat (measures may include, but need not be limited to, phased implementation of beach nourishment, soft protection, managed retreat, focused or small-scale armoring) and a time line or event driven schedule for implementation of the plan.

The plan shall evaluate and consider all potential constraints, including geotechnical and engineering constraints; potential phasing options with timelines; project costs for the preferred project and alternatives; and potential funding options. The plan shall be submitted with documentation sufficient to support all analyses, methodologies, and conclusions.
(c) If the permittee proposes to retain any portion the shoreline protection beyond the~ thirteen year authorization period in the permit application required by subsection (b) of this Special Condition or in a separate amendment to this permit, the permittee is required to include in the permit application an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP. The permittee must also include mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial~ thirteen year period of authorization.

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June 24, 2026
Notice of Proposed Immaterial Permit Amendment
6-16-0450-A2
All other Standard and Special Conditions for CDP No. 6-16-0450 remain unchanged and in effect.

If you wish to register an objection to the processing of this amendment application as an immaterial amendment, please send the objection in writing to [email protected] or the address above.

If you have any questions about this notice, please contact Chelsea Jander at [email protected] or the phone number provided above.

Original on File signed by:

Chelsea Jander
Coastal Program Analyst
cc: Commissioners/File

P, SURFRIDER
~FOUNDATION.

July 3, 2026
Delivered via email
To: Kate Huckelbridge, Executive Director, California Coastal Commission; South Coast District Office, California Coastal Commission Re: Objection to Immaterial Processing -CDP Amendment No. 6-16-0450-A2 Dear Executive Director Huckelbridge and San Diego Coast District Staff, Attachment C
We submit this letter to object to the processing of CDP Amendment No. 6-16-0450-A2 as an immaterial amendment. The proposed amendment would extend the authorization period for the Carlsbad Boulevard rock revetment north of Encinas Creek by seven additional years, from an initial six years (to March 14, 2024) to thirteen years (to March 14, 2031 ). It more than doubles the authorization period the Commission actually evaluated and conditioned when it approved the underlying permit in 2018.

Under 14 CCR§ 13166(b)(3), an objection that raises an issue of Coastal Act conformity requires that the amendment be referred to the Commission for review as a material amendment. Keeping an unmitigated rock revetment on a public beach for seven more years implicates Coastal Act§ 30235, which allows shoreline protective devices only under limited conditions, when required, and only when designed to eliminate or mitigate their impacts to shoreline sand supply. That mitigation has never been required here, which is precisely what Special Condition 1 (c) was written to address. The extension also implicates§ 30253 and the public access and recreation policies of§§ 30210 through 30221. The Executive Director's finding that "no adverse impacts are anticipated" is not consistent with these ongoing impacts, including the public beach area the revetment occupies and its ongoing impacts to shoreline sand supply. We therefore ask the Commission to decline to process this amendment as immaterial and to review it as material.

Background
Carlsbad Boulevard, formerly Highway 101, runs the length of the City along the coast. During the 2015-2016 El Nino, wave and cobble inundation at this location (known locally as "the dip in the road") prompted an emergency permit (G-6-15-0049) on December 29, 2015, authorizing a 270-foot rock revetment. In 2018, the Commission approved CDP 6-16-0450, granting follow-up approval to retain that revetment and after-the-fact approval of an additional 250-foot segment installed in 2016, for five years, specifically to give the City time to develop a Long-Term Hazards P.O. Box 73550, San Clemente, CA 92673 I [email protected] I 949.492.8170 I surfrider.org Management Plan. In 2023, the Commission processed a one-year extension (A 1) as immaterial. The City now seeks a seven-year extension (A2), also as immaterial.

The mitigation requirement has never been triggered, and this amendment would extend that outcome by seven more years
Special Condition 1 (b) required the City to apply for a regular CDP implementing a Long-Term Hazards Management Plan no later than the end of the authorization period. Special Condition 1 (c) required that if the City sought to retain the revetment beyond that initial period, the permit application must include an alternatives analysis and mitigation for the effects of the remaining shoreline protection on public access, recreation, and other coastal resources for its expected remaining life.

Neither has happened. Instead of submitting the complete long-term plan the application 1 (b) requires, the City has twice sought -and now seeks a third time -to extend the "initial" authorization period itself. Each extension pushes the 1 (b) deadline forward without ever requiring the alternatives analysis or mitigation that 1 (c) requires for continued retention of the armoring. A seven-year extension does the same thing at a scale that changes the character of the permit: total authorization would run thirteen years, more than double the five-year term the Commission evaluated and conditioned in 2018. The scope and effect raise the question of whether this qualifies as 'immaterial.'
The City's own record shows initial progress, then an abrupt halt • The City's 2017 SLR Vulnerability Assessment identified this stretch as vulnerable to erosion and flooding and recommended relocating the road inland. • A 2020 California Coastal Conservancy Climate Ready grant funded a study of the corridor that presented the City two options -Retreat Now or Phased Retreat. The results were packaged as a partial Long-Term Hazards Management Plan, completed in February 2024.
• The City Council approved a preferred design alternative for future realignment of southbound Carlsbad Blvd. along the one-mile "dip in the road" stretch in June 2023. • The City's 2023-2027 Five-Year Strategic Plan lists the South Carlsbad Boulevard Realignment as a "Priority Project," targeting completed design and permitting by 2027. • The City's most recent Capital Improvement Budget, passed June 16, 2026 -eight days before this notice was issued -allocated $0 to completing design and permitting for the project, and estimates a $0 allocation through 2031.

The City has the vulnerability assessment, the partial Hazards Management Plan, and two viable long-term management pathways. What it hasn't done is dedicate funding to make progress toward finishing the job, and a seven-year extension removes the deadline pressure that would otherwise hasten that decision.

Surfrider commends City staff for repeated attempts to secure grant funding to continue this project, including a recently submitted $2m Ocean Protection Council Sea Level Rise Adaptation Implementation Grant. Our understanding is that so far, none of the previous grant applications have been successful. A lack of grant funding, however, is insufficient to justify a potential seven-year delay in devising, permitting, and implementing a 30%-designed adaptation project that moves a critical road out of harm's way while durably preserving an entire stretch of popular, public beach.

The City has the money. Carlsbad is financially healthy, with an estimated budget reserve of $144.6m. This amounts to a 58% reserve that comfortably exceeds the City's own preferred minimum of 40%. And the City funds coastal work on Carlsbad Boulevard when it chooses to. It previously appropriated upwards of $12m to Carlsbad Blvd. street and sidewalk improvements less than a mile north of the revetment in question, and returned an estimated $4.5m of that funding to the CIP fund after the City Council voted down several of those improvements (CIP 6054, Terramar Area Coastal Improvements). It appropriated over $13m to beach access improvements further north on Carlsbad Blvd., much of the work dedicated to sidewalk widening that is welcome but cannot be considered critical (CIP 3896, Beach Access Repair and Upgrades -Pine Avenue to Tamarack).

For reasons unknown to Surfrider, the City has deprioritized moving forward expeditiously on this project despite the strong, enforceable conditions it agreed to in Special Conditions 1 (b) and 1 (c). This is a matter of priorities as much as unsuccessful grant funding. The requested delay is unnecessary and will have adverse impacts on coastal resources.

The adverse impacts of delay are not hypothetical
This stretch of road already overtops during king tides and large swells at high tide. Forecasts for an El Nino winter in 2026-27 raise the realistic prospect of further bluff failure, additional emergency armoring, or road closures before this extension period even runs its course.

Another seven years without action virtually ensures a repeat of the pattern that produced the original 2015-2016 emergency permits, now with more of the coastline already committed to rock shoreline protection. But a future failure here would not be the kind of unexpected event that emergency authorization exists to address. The City has documented this precise vulnerability since at least its 2017 Sea Level Rise Vulnerability Assessment, and the original 2015-2016 emergency armoring that preceded it put both the City and the Commission on notice earlier still. Further storm-driven damage is foreseeable, not unforeseen. Granting seven more years of delay would set up the City to seek additional emergency armoring for a hazard it has long anticipated, and is now choosing not to address. Wave action has already begun cutting behind the northern border of the revetment, in the same proximity to where partial bluff failures have repeatedly occurred over the past few years. Without expeditious progress towards the Long-Term Hazards Management Plan the City committed to and is now attempting to extend for more than double the time of the original permit, adverse impacts to coastal resources and public access along this stretch of coast are guaranteed.

Request
We ask the Executive Director to decline to process this amendment as immaterial. For the reasons above, the amendment raises issues of conformity with the Coastal Act, and under§ 13166(b)(3) it should be referred to the Commission for review as a material amendment.

Alternatively, issuance of an immaterial amendment for a shorter extension period, i.e. 2-years, would be an acceptable alternative course to give the City enough time to satisfy Special Conditions 1 (b) and/or 1 (c).

Thank you for your consideration.

Sincerely,
Mitch Silverstein
California Policy Senior Coordinator
Surfrider Foundation
[email protected]
619.736.7757
Kathleen Steindlberger
Carlsbad Resident
Former Carlsbad Beach Preservation Commission Chair
Surfrider San Diego County Beach Preservation Committee Member [email protected]
Jim Jaffee & Kristin Brinner
Beach Preservation Committee Leads
Surfrider Foundation San Diego County
[email protected]
-~ii;?
South Carlsbad Climate
Adaptation Project
Long-Term Master Plan/ Adaptive
Management Plan
City of Carlsbad
28 February 2024
Attachment D
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Contents

1. Introduction 1

2. Proposed Project 3

3. Coastal Hazards 5

3.1 Cliff Erosion 5

3.2 Coastal Flooding 6

4. Adaptive Management Plan 8

4.1 Project Segments 8

4.2 Selected Metrics & Thresholds 9

4.2.1 Cliff Erosion 9

4.2.2 Coastal Flooding 10

4.2.3 Armoring Integrity 10

4.3 Adaptation Pathways 11

4.3.1 Palomar Airport Road Segment 11

4.3.2 Solamar Drive Segment 14

4.3.3 Las Encinas Creek Segment 17

4.3.3.1 Adaptive Pathways 19

4.3.3.2 Trade-offs between Phased Adaptation and Retreat Now Options 21

4.3.4 Island Way Segment 22

5. Monitoring Framework 23

6. Conclusions 25
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Table index
Table 1. Summary of Key Advantages, Disadvantages and Trade-offs between the Phased Adaptation and Retreat Now Options 21
Table 2. Proposed Monitoring Activities to Inform Proposed Adaptive Pathways 23 Figure index
Figure 1. South Carlsbad Boulevard Climate Adaptation Project Area 2 Figure 2. Preferred Project 3
Figure 3. Typical Roadway and Bridge Cross Sections 3
Figure 4. Typical Mobility Corridor Section 4
Figure 5. Modeled Average Cliff Retreat Distance in Tabular Format and Graphical Format 6 Figure 6. Cliff Hazards in the Project Area with Sea Level Rise Projections for 2070 and 2120 6 Figure 7. Coastal Flood Hazards in the Project Area -Entire Project area and Las Encinas Creek using CoSMoS 3.0 with 2050 -3.3-ft SLR and 2100 -6.6-ft SLR 7 Figure 8. Adaptive Management Plan Project Segments 8
Figure 9. Diagram of Cliff Erosion Illustrating Specific Terms 9 Figure 10. Increments of 10-ft Setbacks Across the SLR Projections of Cliff Top Retreat 1 0 Figure 11. Adaptive Pathway for Palomar Airport Road Segment 11 Figure 12. Phase 0 (as-built condition) of Palomar Airport Road Segment 12 Figure 13. Palomar Airport Road Segment -Adaptive Phase 1 12 Figure 14. Palomar Airport Road Segment -Adaptive Phase 2 13 Figure 15. Palomar Airport Road Segment -Adaptive Phase 3 13 Figure 16. Proposed Adaptive Pathways for Solamar Drive Segment 14 Figure 17. Phase 0 (as-built condition) of Solamar Drive Segment 15 Figure 18. Solamar Drive Segment -Option 1 16
Figure 19. Current Intersection at Solamar Drive and Informal Beach Accessways Compared with a Nearby Example of a Formalized Staircase at South Carlsbad State Beach as an example to inform Option 2 16
Figure 20. Phase 0 in the Las Encinas Segment overlaid with flood and cliff erosion hazards. 18 Figure 21. Phase 0 (as-built conditions) for the Phased Retreat Alternative 18 Figure 22. Phase 0 (as-built conditions) for the Retreat Now Alternative 19 Figure 23. Adaptive Pathways for Las Encinas Creek Segment 20 Figure 24. Phase 0 (as-built condition) of the Island Way Segment 22 Photo index
Photo 1. Cliff Erosion within the Project Area near Palomar Airport Road and Solamar Drive Photo 2. Coastal Flooding within the Project Area
5 7
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

1. Introduction
Traffic safety and environmental sustainability are top priorities for the City of Carlsbad. A California State Coastal Conservancy grant provided the city with an opportunity to advance both priorities by redesigning a section of Carlsbad Boulevard prone to flooding and other coastal hazards. The grant is intended to demonstrate how coastal cities can move and adapt infrastructure based on the latest modeling of sea level rise (SLR).

The South Carlsbad Climate Adaptation Project seeks to move the southbound lanes of Carlsbad Boulevard from Manzano Drive to Island Way to the east and repurpose city-owned land for other public uses and environmental restoration areas. The uses for this space and the future alignment of the road are focused on building resilience into the corridor with consideration of current and projected future coastal hazards; specifically, SLR and cliff/shoreline retreat over the next 100 years.

To meet these objectives, the proposed project involves a complete street to include coastal trails, bikeways and sidewalks that provide access to the coastline and community vision spaces (Figure 1). Complete streets are streets that are safe and inviting for all users, including people of all ages and abilities, regardless of whether they are driving, biking, or walking. Additionally, the project involves the use of nature-based design techniques and achieving habitat restoration where viable and appropriate -such as within the Las Encinas Creek area.

This Long-term Master Plan / Adaptive Management Plan (plan) was prepared to inform the management of the project elements over time in what is envisioned to be a phased plan in response to future coastal hazards. The plan presents physical thresholds for management actions (such as moving infrastructure elements landward) as coastal hazards impact and make coastal spaces unsafe for the public to recreate in.

It is important to note that the project design is still in the conceptual engineering phase (30% design) at the time of this plan's development. This plan may require revision during the final engineering and environmental phase to reflect any design changes that emerge.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 1. South Carlsbad Boulevard Climate Adaptation Project Area South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

2. Proposed Project
A preferred option was selected by the Carlsbad City Council on June 20, 2023, that balances the project goals of improving mobility and coastal access, while reducing the risk of infrastructure to hazards and increasing resilience to the corridor by moving infrastructure inland and out of coastal hazard zones. The primary elements of the project are to: 1) create a complete street along the existing northbound Carlsbad Blvd alignment; 2) enhance traffic circulation and safety through three roundabouts; 3) restore habitat and promote wildlife connectivity in Las Encinas Creek through construction of a 500' span bridge along new complete street; and 4) increase mobility through creation of a Class 1 bikeway facility and complete street elements on Carlsbad Blvd. The proposed project and primary components are shown in plan and section in Figures 2 through 4. Details on adaptation considerations for specific assets along the project area are further described in this report in Section 4.3 .

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VAR 2' 10'

I SIDEWALK
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8' 3'

BIKE BUFF
Jo 2%
12'

CLASS I PATH
. I I
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Figure 2. Preferred Project
73'

10.5' 4' 10.5'

VEHICLE VEHICLE
t t 2%

TYPICAL ROADWAY CROSS SECTION
N.T.S
86'
5' 8' 3' 10.5'

MEDIAN/ BIKE BUFF VEHICLE

BARRIER
-
Jo ~ 2%

TYPICAL BRIDGE CROSS SECTION
N.T.S
3' 8'

BUFF BIKE
Jo
4'
MED.
~
8' 8'

LID SIDEWALK

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VEHICLE BUFF BIKE
t 2% Jo
Figure 3. Typical Roadway {above) and Bridge (below) Cross Sections 2' VAR RN/
RJW
8' 12' VAR

SIDEWALK I
C
J
I
F
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan 2' 10'
PED

1.5%
-
36'

TYPICAL
20' WIDE CLASS 1
4' 2' 8'

1.5%
-

TYPICAL TRAIL CROSS SECTION
N.T.S
8'
Figure 4. Typical Mobility Corridor Section
R/ w
2' VAR
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

3. Coastal Hazards
Coastal flooding and cliff erosion are the primary hazards that present vulnerabilities to the project site. These coastal hazards have required temporary roadway closures and the installation of rock revetment along 1,300 LF of southbound Carlsbad Blvd. Assessment of future coastal hazards driven by climate change and SLR indicate that both flooding and erosion will increase over time, causing additional impacts to access and usability of infrastructure without the interventions proposed by the project and presented in this plan. The impacts from these hazards are the focus of the adaptive management principles identified in this plan. This report summarizes information on hazards with detailed analysis available in the Cliff Erosion Assessment Report and Coastal Hazards Memorandum.

3.1 Cliff Erosion
Currently, cliff erosion presents a significant hazard across the project area. Episodic cliff failure events have occurred within the project area which have led to substantial erosion (Photo 1 ). To understand the existing and projected future cliff hazards in the project area, Scripps Institution of Oceanography (SIO) conducted a study of cliff erosion. This study assessed existing conditions, developed historic retreat rates, and projected cliff positions with SLR rates consistent with the Ocean Protection Council (OPC) 2018 medium-high scenario. This effort was undertaken by using four cliff evolution models and hundreds of model runs. All four models assumed erosion is primarily driven by wave action. It is important to note that other erosive processes, such as rainfall and groundwater, were not explicitly modeled though are generally captured in the historic retreat rates used as a baseline input for the models.

Photo 1. Cliff Erosion within the Project Area near Palomar Airport Road (left) and Solamar Drive (right) Source: Hayne Palmour IV (left), Sean Williams (right)
To derive retreat rates and corresponding cliff edge positions from the SIO model results, statistics (i.e., mean, median, percentiles, max/min) were calculated for each model run corresponding to the years of interest (2030, 2050, 2070, 2100). The SIO study did not extend beyond 2100, thus projections of cliff retreat were forecasted to a line of best fit to estimate year 2120. A spatial representative of these projected cliff edge positions (i.e., cliff hazard zones) was created using the average distance of each model run for the years 2070 and 2120. These results are presented graphically in Figure 5 with the statistical mean (i.e., average) projections of cliff retreat distances from the baseline cliff edge highlighted. A cliff erosion hazard zone was created from the results of the SIO study and is overlain on the project site in Figure 6.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan 2050 22.6
2070 40.5
2100 77.5
2120* 108.1
·sIO modefing does not project past 2100,
interpolation wos used to derive the 2120
value
€ .

C
ll c
;,
;
~
~ u
200
--M<llcRc11ra1
I/',, -t-Ql
~Avr, Retreat
150 -Q3
m
100
75 0.9'SLR
50 )5
2010 2030
S10 Modeled Cliff Retreat

7.l'SLR

3.6'5LR 8.B'SLR

2.0'SLR
2050 2070 2090 2110
Time Horiwn
Figure 5. Modeled Average Cliff Retreat Distance in Tabular Format (left) and Graphical Format (right) (Derived from: SIO 2022)

3.2 2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 6. Cliff Hazards in the Project Area with Sea Level Rise Projections for 2070 and 2120 Coastal Flooding
ll30
....

Coastal flooding is when water floods (short duration standing water) or inundates (long duration standing water) over typically dry land as a result of tides and waves. Coastal flooding of low-lying shorelines will increase in frequency and severity as sea levels rise. Coastal flooding was assessed within the project area using USGS's CoSMoS 3.0 under the year 2050 (3_3-ft SLR scenario) and the year 2100 (6.6-ft SLR scenario). Flood hazards are focused along the low-lying areas around Las Encinas Creek (Figure 7). This finding is consistent with existing conditions, as the roadway currently experiences overtopping and closures at this location during extreme waves coincident with high tide events (Photo 2).

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Photo 2. Coastal Flooding within the Project Area
(source: City of Carlsbad)
lllcflt .. Wryt~
NJtunt~l•""AH ...
-
--~
Right of Way Limit with
adjacent_Class I and Sidewalk J
Year 2050 Flood Hazard Zone
slower moving mo ty opt ons
Year 2100 Flood Hazard Zone
Figure 7. Coastal Flood Hazards in the Project Area -Entire Project area (top) and Las Encinas Creek (bottom) using CoSMoS 3.0 with 2050 -3.3-ft SLR (light blue) and 2100-6.6-ft SLR (dark blue) South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4. Adaptive Management Plan
An adaptive management approach will be used to inform project phasing over time with the overall goal of utilizing coastal spaces for public mobility and recreation until erosion or flooding make these spaces unsafe for the public to use. The Adaptive Management Plan presents adaptive pathways for each of the four project segments. These pathways outline a management and decision framework based on the coastal hazards that are anticipated to impact these areas over the next century. These pathways are comprised of monitoring thresholds for various metrics and management actions, which are described in detail in this section.

4.1 Project Segments
For the purposes of this Adaptive Management Plan, the project area was divided into four segments based on common vulnerabilities and how these infrastructure elements could be managed or adapted over time (Figure 8).

These segments are described as follows:

1. Palomar Airport Road Segment -Encompasses the area from Manzano Drive to Palomar Airport Road. This segment includes the Turnarounds Parking Lot, owned by State Parks.

2. Solamar Drive Segment -Centered on the intersection of Solamar Drive and South Carlsbad Blvd.

This intersection primarily serves as the main vehicular accessway for both the Solamar Community and Hilton Garden Inn. This segment also includes the City Parking Lot at Dave's Beach and the RC Flyers Lot.

3. Las Encinas Creek Segment -Centered at the Las Encinas Creek and includes the North Ponto State Beach Day Use Parking Lot.

4. Island Way Segment -Southernmost end of the project area that encompasses an intersection at Island Way located inland from the South Carlsbad State Beach Campground.

Palomar Airport Road
Se ment
Las Encinas Creek
Se
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 8. Adaptive Management Plan Project Segments
'Island Way
Segment
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4.2 Selected Metrics & Thresholds
The physical metrics and thresholds that were selected to prompt management actions in the project area are tied to the vulnerabilities and public use of the site. The three selected metrics include: cliff erosion, coastal flooding, and armoring integrity. Example thresholds that would prompt adaptive management action for each of these metrics are provided below:
• Cliff erosion (e.g., cliff erodes within several feet from edge of buffer to bikeway), • Coastal flooding (e.g., frequency of infrastructure flooding), and • Armoring integrity (e.g., cost of maintenance and repair), Site usability (by the public) was considered as a metric, however, to provide more objective thresholds it was not included as it was acknowledged that usability is captured indirectly across the other evaluated metrics. Further explanation of the thresholds selected for each of the metrics is provided in this section.

4.2.1 Cliff Erosion
The cliffs within the project area are vulnerable to erosion primarily as a result of waves attacking the cliff face, resulting in instability and surface runoff physically eroding the cliffs. For the purposes of evaluating metrics and setting thresholds for cliff erosion, both setback and buffer distances are being used. Cliff erosion setback refers to the distance from the top of cliff edge to a buffer. Recognizing potential safety concerns with infrastructure abutting a cliff edge, a cliff erosion buffer was applied as a threshold for management actions. Cliff erosion buffer refers to the distance from the setback to the asset (e.g., trail, roadway, etc.). These terms are illustrated schematically in Figure 9. By having the setback relate to the buffer allows additional time to plan management actions and safe use of the asset during that time.

Top of Cliff
Edge
Toe of Cliff
j Setback l Buffer l Asset
l
Figure 9. Diagram of Cliff Erosion Illustrating Specific Terms The setback distance from the buffer to the top of cliff edge was selected as the most appropriate threshold for cliff erosion. To determine the appropriate setback distance threshold, the approximate lead times for the various management actions was discussed with city staff. Lead times for the relocation or realignment of proposed project infrastructure (primarily the bikeway corridor) ranged from three to 10 years across the segments. When comparing this to the localized cliff erosion projections (Figure 10) using the average cliff erosion, the 10-ft setback is projected to provide roughly 10 years of lead time between 2030 and 2090, and roughly five to seven years of lead time at the end of the century. This lines up with the expectations for planning, design, fundraising, and implementation of the management actions identified. A buffer distance of five feet was determined appropriate to allow for time and space for safe usage of the asset during lead times and allows for the uncertainties in the magnitude of future bluff failures.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan 200
180 I
160
140
g .,
u
C
t: 120 I 0
~
j 100
a.
0 >-
~
80 I u
60 40
20 0
2020

4.2.2 10 ft Setback Increments Overlaid on S10 Modeled Cliff Retreat -1+-Max Retreat 7.1' SLR
~Ql
-++-Avg Retreat
Q3
----Min Retreat

3.6' SLR
CJ->
__________ 2_!)3~----------------------------------
1030 1040 2050 2060 2070 1080 2090 2100 2110
Time Horizon
Figure 10. Increments of 10-ft Setbacks Across the SLR Projections of Cliff Top Retreat Coastal Flooding

8.8' SLR
10 ft Setback
lncremcnls
2120 2130
Infrastructure in the project area is vulnerable to coastal flooding as a result of the proximity to the ocean and the elevation of infrastructure in the Las Encinas Creek vicinity. Coastal flooding of public spaces is a safety hazard and can result in road closures. This metric consists of partnering with SIO to use combined tidal conditions (predictions and observations) and wave modeling outputs to determine and validate flood elevation thresholds (e.g., minor, moderate, significant) and track flooding over time. For example, some overtopping of the roadway that does not impact vehicular use could be considered minor flooding, while overtopping sufficient to close the roadway to vehicles could be considered significant flooding. The exact elevation and oceanographic conditions to define flooding thresholds will be determined and validated at a later date. This information could be added to the existing SIO website1 and linked through a city webpage. Automated emails to city staff could be generated in anticipation of forecasted flood events. This could be supplemented with site observations captured during extreme events with a field sheet and/or photos. Based upon the current frequency of extreme flooding and overtopping observations, a flooding threshold was defined as significant flooding of infrastructure 10 times in one year (i.e., 12-month period). Once validated, this method could be used to identify and track these flooding events.

4.2.3 Armoring Integrity
Should the beach undergo significant erosion, the rock revetment currently stabilizing southbound Carlsbad Blvd will be vulnerable to damage, which could impact its effectiveness at protecting the roadway. Damage has been documented previously during the 2015-2016 El Nino event, which compromised the integrity of the roadway and required emergency repairs and road closures. The need to extend or repair a significant segment of rock revetment (i.e., 500 LF) was selected as the threshold for armoring integrity. A financial threshold was also selected alongside this that would be met if repair, maintenance, or damage to the rock revetment exceeds $SM (2023 dollars) over two years (i.e., 24-month period).
1 An example of this system for Imperial Beach is available here: https://siocpg.ucsd.edu/data-products/coastal-focus-sites/ch-imperial beach/ib-flood-forecast/
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4.3 Adaptation Pathways
This section presents the adaptive pathways for each of the four project segments. Each of the pathways presented begins with Phase 0, which is considered the constructed project as currently proposed. The pathways then propose a number of future phases (i.e., management actions) and the thresholds/triggers that would cause the city to begin planning or implementing that future project phase. Understanding that each management action takes several years to implement, appropriate lead times were incorporated into the pathways. These lead times were derived from conversations with city staff and based upon analogous projects that have been implemented in the city.

4.3.1 Palomar Airport Road Segment
The main vulnerability of concern in this segment is cliff erosion. Four potential phases have been identified in the adaptive management plan for this segment (Figure 11 ). The overall theme of these phases is to narrow and eventually relocate the proposed trails over time with the goal of keeping this mobility corridor in close, but safe, distance from the ocean to maximize coastal views from the trails.

Phase O
Mobility Corridor
----*• I Phase 1
I Shared Class 1 Corridor
-----~
Triggers
* Pedestrian walkway 15' from cliff edge.
* Bikeway 15' from cliff edge.
* Relocated bikeway 15' from cliff edge.

Distances Include 5' buffer between setback and asset
I Phase 2
I Relocated Class 1 ......

I I Phase 3
OR I Demolish Corridor & Redirect
1 Active Recreation to New Roadway -
Begin planning & implementation of Phase 1 (lead time assumption 3-5 yrs') Begin planning & implementation of Phase 2 (lead time assumption 3-7 yrs') Begin planning & implementation of Phase 3 (lead time assumption 3-5 yrs') 'Assumes PEIR and available fundinq
Figure 11. Adaptive Pathway for Palomar Airport Road Segment The first line of infrastructure to be impacted by cliff erosion in the future would be the Class I pedestrian and bicycling trail in Phase 0, the as-built condition (Figure 12). The first adaptive phase is triggered once the cliff edge encroaches within 15' of the proposed pedestrian trail, which includes the 5' buffer. Phase 1 would then transition the pedestrian trail and bikeway into a shared use, Class 1 corridor (Figure 13). A combined pedestrian and bike corridor is a common configuration along the Coastal Rail Trail in North County San Diego, likely requiring a minimal learning curve for users as the pedestrians and bikes are merged into a single multi-use trail.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan 'Palomar Airport Road Segment -
Phase O (As-Built Condition}
'" PED

TYPICAL
WIDEClASS 1
4' 2' B' 8'
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 12. Phase O (as-built condition) of Palomar Airport Road Segment 'Phase 1 (Mobility Corridor reduced to shared
use Class 1 Corridor)
20 T'/PIC/\l
20' WIDE CLASS 1
~ ~
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 13. Palomar Airport Road Segment-Adaptive Phase 1 As the cliff top continues to erode and becomes within 15' from the shared use trail, the next phase would relocate the trail landward in incremental steps (Phase 2) (Figure 14). The relocated trails could be developed with low cost and less permanent materials, allowing for lower expenditure and increased flexibility in the modifications. As an South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan alternative phase to Phase 2 and/or when a trail would be infeasible, the city could decide to demolish the built trail corridor and redirect all active recreation to the proposed complete street roadway (Phase 3) (Figure 15). 'Phase 2 (Move Class 1 Corridor Landward
Incrementally)
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 14. Palomar Airport Road Segment-Adaptive Phase 2 'Phase 3 (Demolish Mobility Corridor &
Redirect Active Recreation to New Roadway)
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 15. Palomar Airport Road Segment-Adaptive Phase 3 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan California State Parks owns and manages the land where informal parking occurs (commonly referred to as Turnarounds Lot). The city is actively coordinating with State Parks as part of this project; however, adaptation of the parking lot is not included in this Plan. Future phases of the project would provide more details on how the project interacts with this parking lot and how the parking lot could adapt over time.

4.3.2 Solamar Drive Segment
The main vulnerability of concern in the Solamar Drive Segment is cliff erosion. One phase with two potential options has been identified in the Adaptive Management Plan for this segment (Figure 16). The overall themes of these phases are to utilize the roundabout as long as feasible with options to explore increased access and stabilization (i.e. erosion control) alternatives as well as potentially changing the roundabout to a signal to regain some space.

Triggers
Phase 0
Roundabout
t• Option 1
I Bidirectional Roadway w/ Signal
I
OR Option 2
I Evaluation of Stabilization and Access Alternatives
* Class 1 Bikeway 15' from cliff edge. Begin planning & Implementation of Phase 1 (lead time assumption 5-10 yrs•) *Assumes PEIR and available funding Distance include 5' buffer between setback and asset Figure 16. Proposed Adaptive Pathways for Solamar Drive Segment The first line of infrastructure to be impacted by cliff erosion in the future would be the pedestrian trail in Phase 0, the as-built condition (Figure 17). The 2070 Cliff Hazard Zone encroaches on the proposed pedestrian trail. By 2120, the Cliff Hazard Zone is projected to encroach to the middle of the proposed roundabout (Figure 17).

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Solamar Drive-Phase 0
2070 Cliff Hazard Zone
[: 2120 Cliff Hazard Zone
Figure 17. Phase O (as-built condition) of Solamar Drive Segment Phase O (as-built) positions infrastructure as landward as possible to achieve the project goals. As the cliff erodes and encroaches on the roundabout, two options are available that would address the functionality and usability of the intersection and coastal resources. Option 1 would involve the planning and implementation of transitioning the roundabout to a signalized intersection that requires less space (Figure 18). Concurrently or independently to Option 1, Option 2 would explore cliff stabilization and erosion control techniques coordinated with a new formalized vertical access point to achieve multiple benefits at this location. For example, a wooden staircase, similar to nearby accessways, that blends into the coastal cliff landscape could be feasible at this location. An example of a nearby formalized cliff access point that could inform Option 2 is provided in Figure 19. This accessway would relieve the need for multiple desire paths that currently exist along the cliff face where beachgoers and surfers traverse down the cliff to reach the shore. A multi-benefit solution exists to provide cliff stabilization and erosion protection at the landing of this accessway on the beach. The erosion protection would be designed to the minimum necessary footprint and the accessway designed to allow safe and appropriate width access to the beach while increasing the stability of the cliff fronting the roundabout at Solamar Drive. Both Option 1 and Option 2 could be pursued once the cliff erodes within a distance of 15' from the vehicle lane which includes a 5' buffer.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Solamar Drive-Option 1
(Bidirectional Roadway with Signa~--
~~ ...
• -
~ '----...
2d10 C)iff I
zartf tone
Figure 18. Solamar Drive Segment-Option 1
Figure 19. Current Intersection at Solamar Drive and Informal Beach Accessways (left) Compared with a Nearby Example of a Formalized Staircase at South Carlsbad State Beach (right) as an example to inform Option 2.

Source: Copyright© 2002-2019 Kenneth & Gabrielle Adelman, California Coastal Records Project, www. cal iforn iacoastlin e. org
South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4.3.3 Las Encinas Creek Segment
The vulnerabilities in the Las Encinas Creek segment are cliff erosion and coastal flooding, with coastal flooding within the "dip in the road" along southbound Carlsbad Blvd at the mouth of Las Encinas Creek being the primary concern (Figure 20). Both of these vulnerabilities can be seen in present day as the cliffs have been protected by a rock revetment and the road periodically floods when waves overtop this structure.

Two different project options have been identified in this segment for how and when infrastructure is adapted each with different levels of hazard exposure. These options, called 1) Phased Adaptation and 2) Retreat Now, result in differing adaptation pathways. The Retreat Now option builds the project segment to the ultimate 2120 condition immediately, while the Phased Adaptation option repurposes the coastal infrastructure by creating a mobility corridor upon it in the as-built or Phase O of the project, to be used for as long as it is safe for the public. These options present key project decisions to be made by the City Council with input from the community and other affected stakeholders, and, ultimately, come down to how they would like to use these spaces now and in the future and what funding sources could be identified for improvements.

The Encina Wastewater Authority (EWA) provides wastewater treatment services to more than 379,000 residents in northwestern San Diego County with a facility located inland of the project area. The EWA has an existing ocean outfall that extends roughly 1.5 miles offshore to a water depth of 150ft. The outfall pipeline intersects southbound South Carlsbad Blvd approximately 200ft south from the centerline of the Las Encina Creek bridge (see callout for existing 48" EWA outfall in Figures 21 and 22). As-builts indicate that the pipeline is approximately 5ft below the current grade of the roadway. All adaptation options for the roadway will need to account for the protection of the existing EWA outfall pipeline. Further coordination with EWA will be needed during the next phase of this project (i.e., final engineering) to refine protection or accommodation options. as this infrastructure is outside of the City's sole jurisdictional authority.

The two adaptation options being considered for the Las Encinas Creek Segment are further described below:

Phased Adaptation: This would either leave in place or partially remove the southbound Carlsbad Blvd infrastructure for interim passive or active recreational uses until coastal hazards overwhelm the repurposed space. Once one of the identified triggers is met, the southbound roadway would be demolished, and recreational uses would shift to either the new complete street corridor or a new Class 1 boardwalk, depending on the identified trigger. Major infrastructure elements (e.g., the complete street roadway) would be constructed at its ultimate location while other temporary/movable, low-cost project features would provide amenities in the interim in spaces currently identified as being vulnerable to projected coastal hazards. The existing rock revetment will persist to support the use of the newly created space on the southbound roadway.

Phased Adaptation is shown graphically in Figure 21.

Retreat Now: This option refers to the naturalization of the southbound roadway area by removing infrastructure within the.2100 projected Coastal Hazard Zone and restoring the La Encinas Creek estuary system. More specifically, this alternative seeks to establish a more natural cross-shore gradient promoting morphological processes that support the formation and resilience of a coastal pocket beach, dune, and dune slack wetlands. The Las Encinas Creek estuary and beach would be allowed to evolve naturally and without major maintenance after the project is constructed. The infrastructure to be removed includes the existing southbound Carlsbad Boulevard bridge structure, 1,300 LF of rock revetment, and the existing roadway surface (i.e., asphalt) and fill prism (i.e., compacted dirt used to form the roadbed). The goal would be to reuse rock from the deconstructed revetment in other areas of the larger project that may require stabilization material (e.g. bridge abutments or EWA outfall protection). The Retreat Now option is shown graphically in Figure 22.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan -
Oceanvlew Dr
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Oceanvlew Dr
Year 2050 Flood Hazard Zone
Las Encfnas Creek
500' Span
Bridge
"Complete Street" roadway
with sidewalks and bikeJa))eS
Vear 2100 Flood Hazard Zone
Figure 20. Phase O in the Las Encinas Segment overlaid with flood (top) and cliff erosion (bottom) hazards.

Legend
GJ ~~e~tf~~~iancement
I PIP• Protect In Place I
Figure 21. Phase O (as-built conditions) for the Phased Retreat Alternative South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 22. Phase O (as-built conditions) for the Retreat Now Alternative

4.3.3.1 Adaptive Pathways
Key themes around adaptive pathways for this segment hinge on which option is pursued in this segment (Phased Adaptation or Retreat Now). Since the Retreat Now option is built to a year 2120 resilient location, an adaptive pathway was not developed for that option. The proposed adaptive pathway for the Phased Adaptation option is shown in Figure 23. As shown, two triggers were identified that would signal the need to begin planning and implementation of the removal of the southbound roadway and shifting active transportation users to a new boardwalk or the complete street roadway and bridge. Triggers identified include rock revetment armoring integrity, and flood frequency. A lead time of five to 10 years was identified as sufficient time to plan and implement this management action, assuming the action is included in a programmatic environmental document (assumed PEIR) and funding exists.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Phased Adaptation
I -------Viptn 1 --------,
I I
: Demolish & Redirect Active :
:Transportation to New Bridge : -----------r------------ OR ___________ J ___________ _
Option 2 '
: Demolish & Build
Retreat Now : __ ~-e~ ~!~s_s_ ! _!3_o~~~~~~k-__ _
w/ or wot Class 1 Boardwalk
Triggers Action
* *
Armoring Integrity: Rock revetment repair & maintenance -need to extend or repair a significant segment of rock revetment (500 LF). Repair or damage exceeds $5M (2023 dollars).

Flood Frequency: Significant overlapping of rock revetment and flooding of Mobility Corridor 10 times in one year (i.e., 12 month period).

Begin planning & implementation of Option
1 or 2 (lead time assumption 5-10 yrs')
'Assumes PEIR and available funding
Figure 23. Adaptive Pathways for Las Encinas Creek Segment South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4.3.3.2 Trade-offs between Phased Adaptation and Retreat Now Options The options of Phased Adaptation and Retreat Now each have unique advantages, disadvantages, and trade-offs that warrant evaluation. Table 1 summarizes these to aide in the decision-making process.

Table 1. Summary of Key Advantages, Disadvantages and Trade-offs between the Phased Adaptation and Retreat Now Options Category
Permitting and
Construction:

Can all elements of the
design be implemented
at once?
Financial:

What are the
differences in costs
between the two
options (qualitatively)?
Coastal Hazards &
Public Safety:

Would the option
provide public
protection from existing
and projected future
coastal hazards?
Sandy Beach:

Will the alternative
sustain a dry, sandy
beach in the study
area?
Access:

What are the
differences in public
access and use
between the two
options?
Habitat Restoration:

How would these
options benefit the
restoration of Las
Encinas Creek?
Phased Adaptation
No. This option would occur in phases.

Construction, disruption to traffic flows, and
permitting would need to occur one or more times
once a trigger is met.

This option may be less expensive in the short-term
because it would repurpose the existing southbound
roadbed into a mobility corridor. Thus, the project
would not require the demolition of the bridge, rock
revetment or roadway.

This option may have more expensive construction
costs over a 20-50 year period because it results in
more planning and construction activities spread out
1 over time. Factors to consider include
mobilization/demobilization, pulling construction
permits (e.g., traffic control, etc.), escalation of
material and labor costs, increase in construction
costs, and scarcity of future funding. By waiting until impacts are realized, addressing all future
adaptation needs and costs could vary greatly, likely
being much higher than addressing components all
at once.

Additionally, this option does not take full advantage
of the current availability of state and federal grants to support projects of this type. The availability of
these funding sources for future phases of the
project is unknown.

Yes. This option would repurpose the roadway for
recreational uses until it becomes unsafe to use for
this purpose. The existing rock revetment would
remain in place to protect the roadway from erosion.

Triggers described within this plan identify when the
space needs to be abandoned.

No. The existing beach is narrow. It is anticipated
that with 1. 7' of SLR, the existing narrow beach
within the Las Encinas Creek study area will be
completely eroded/inundated, assuming no other
management actions occur.

This option provides active transportation along the
southbound roadway, closer to the coast and similar
to current conditions. Until triggers are met and the
space needs to be abandoned, access would feel
safer and likely more welcoming given the
elimination of vehicular traffic.

Recreational opportunities along the beach would
remain constrained due to increasingly narrow
beach widths as sea levels rise.

The southbound roadway area will be restored to
coastal strand once the trigger is met. The area to
be restored and viability of the habitat may be lower
than if the habitat was built initially due to elevated water levels and more frequent wave attack.

Retreat Now
Yes. This option would perform all
actions at one time, not requiring any
additional permitting or construction.

Higher costs to construct because it
includes the demolition costs of the
bridge, rock revetment and roadway.

This option would need to protect the
existing EWA outfall, likely with rock
reused from onsite materials
(deconstructed revetment), which adds
additional cost in the short-term.

This option may be less expensive over
a 20-50 year period because it would
construct everything at once in today's
dollars (i.e., reduced escalation).

Additionally, this option could take
advantage of ample state and federal
funding that exists for coastal resilience
projects today. This funding is forecasted
to be available at least over the next 5
years, which could support
implementation costs.

Yes. This option would relocate public
infrastructure out of the Coastal Hazard
Zone for the next 100 years.

Recreational uses of the abandoned
space would be protected through
nature-based design techniques (e.g.,
cobble-sand dune system).

Yes. This option is anticipated to result in
a localized increase in beach area
immediately through removal of the
roadway. Preliminary modeling suggests
this pocket beach may sustain through

6.6' of SLR as the beach and created
dune are allowed to transgress
landward.

Active transportation uses would be
focused along the enhanced roadway,
which would be located further from the
coast and elevated, a changed user
experience from present day.

The removal of the southbound roadway
would enhance existing, and create new,
recreational opportunities from the
additional beach space.

This option restores the southbound
roadway to coastal strand habitat
immediately. The coastal strand habitat
has more space and time to establish
prior to increased water levels and wave
attack, making it a more resilient system.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

4.3.4 Island Way Segment
The main vulnerability of concern in the Island Way Segment is cliff erosion. The first line of infrastructure to be impacted by cliff erosion in the future would be the South Carlsbad State Parks Campground day use lot and overnight areas (Figure 24). Given that the proposed roadway is inland of these campground facilities and significantly inland from the cliff edge, an adaptive pathway was not developed for this segment. Instead, it is recommended that the city continues to coordinate with State Parks regarding their plans to adapt these facilities . •
Island Way-Phase 0
{Roundabout)
2070 Cliff Hazard Zone
2120 Cliff Hazard Zone
Figure 24. Phase O (as-built condition) of the Island Way Segment South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

5. Monitoring Framework
Based upon the thresholds identified within the adaptive pathways for each project segment, monitoring will be required to help understand when a threshold has been met. A monitoring framework was developed with potential methods and data collection frequencies shown in Table 2 below.

Table 2. Proposed Monitoring Activities to Inform Proposed Adaptive Pathways t ••• Frequency
High-tech/ Topographic surveys (traditional survey Semi-annual Surveys Data driven profiles, orthophotogrammetry, LiDAR) Extreme Events Cliff Erosion Site amenities (e.g., colored pavers,
Low-tech/ benchmarks, signs) indicating bluff top Continuous Interpretive edge erosion and encroachment into
established thresholds
Beach Erosion Beach profile surveys (back beach to depth of closure) Semi-annual Surveys Subaerial beach surveys via orthophotogrammetry or LiDAR Extreme Events Rock revetment Topographic Survey (traditional survey profiles, Annual / Armoring orthophotogrammetry, LiDAR) Post Extreme Events Integrity Structural condition inspection Roadway
Maintenance Financial tracking of cleanup and repair activities Annual Costs
Flood elevation thresholds (e.g., minor, moderate, Continuous Flood significant) are determined and tracked by combined tide and Extreme Events Frequency wave observations outputs in coordination with SIO; Supplemented by site observations and closure tracking. Annual Site Observations As Needed Public Access/ Closure Tracking Usability Aggregated Big Data Sources Extreme Events
Further description of the monitoring approach for each of the metrics is provided below:

Cliff Erosion: Since the setback (i.e., distance from the cliff edge to the buffer) is a key threshold in the adaptive management pathways for the segments, cliff monitoring will be important to inform this plan. Two options exist to track cliff erosion in the project area -dubbed low-tech and high-tech options. The high-tech option leverages cliff monitoring currently performed by SIO periodically; however, monitoring at an increased frequency, such as semi-annual, may be necessary to detect and track changes. Monitoring can be performed via traditional survey methods or via drone or plane overflight using orthophotogrammetry or LiDAR methods.

If the city notices significant erosion it may elect to complete an additional survey(s) accordingly. The low-tech option utilizes low-cost methods that may be adequate for certain areas along the project site given the nature of bluff erosion. Benchmarks integrated within the infrastructure amenities could serve as a passive method for tracking cliff erosion. For example, markers or pavers between the setback and buffer could have a progressive color scheme that would identify the setback encroaching on the buffer. Added benefits of this low-tech monitoring technique would be the easy ability of maintenance staff to track changes in the bluff visually, as well as serving as an educational opportunity for the public.

Beach Erosion: Though not explicitly called out as a threshold in the adaptive management pathways, beach conditions have a significant effect on other metrics within this plan -specifically cliff erosion, armoring integrity and flood frequency. Thus, monitoring beach changes quarterly is recommended within the project area. Monitoring should consist of traditional beach profile surveys (back beach to depth of closure) or capturing the subaerial beach with orthophotogrammetric or LiDAR methods. SIO already performs quarterly beach monitoring at South Carlsbad State Beach that can be leveraged to track changes in beach conditions over time.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Rock Revetment/ Armoring Integrity: The rock revetment could shift and become increasingly destabilized as waves of greater magnitude more frequently impact the structure with SLR. The rock revetment is currently monitored annually as part of the city's CDP with the Coastal Commission. It is recommended that this program continue and potentially be increased in frequency as the structure becomes increasingly impacted (e.g., post-extreme event condition surveys). It is also recommended that a coastal engineer or a civil/structural engineer with experience with coastal structures inspect the structure annually to assess its condition.

Roadway Maintenance Costs: Keeping a ledger on annual expenditures for roadway cleanup and repair is important to understand escalating costs of maintaining public use along the repurposed southbound roadway.

This monitoring metric requires a city staff person to organize cost data from various departments into a ledger.

Flood Frequency: This metric consists of partnering with SIO to use combined tidal conditions (predictions and observations) and wave modeling outputs to determine and validate flood elevation thresholds (e.g., minor, moderate, significant and track flooding over time. The exact elevation and oceanographic conditions to define significant flooding will be determined and validated at a later date. Once validated, this tool could be used to identify and track flood events to discern if the threshold of 1 0 flood events in 12 months is triggered. This information could be added to the existing SIO website and linked through a city webpage. Automated emails to city staff could be generated in anticipation of forecasted flood events. This could be supplemented with site observations captured during extreme events with a field sheet and/or photos.

Public Access/ Usability: Though not explicitly called out as a threshold in the adaptive management pathways, site usability is anticipated to change over time as assets experience impacts. These changes can be documented to supplement the objective thresholds selected (e.g., erosion, flooding, and armoring integrity). Methods for tracking this could include site observations, closure tracking of key pieces of infrastructure (e.g., bikeway, roadway, etc.) or through aggregated big data sources which can show usage patterns derived from cell phone data.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan

6. Conclusions
This Adaptive Management Plan presents adaptive pathways for the project, divided into four discrete segments.

These pathways identify future management actions that will be taken once coastal hazards meet certain thresholds or triggers. These thresholds vary from proximity to the proposed infrastructure elements, flood frequency, and armoring integrity and maintenance costs. A monitoring framework was developed to help the city identify and track metrics over time to determine when thresholds are met.

The adaptive pathways for each of the four project segments are summarized below:

Palomar Airport Road: Four potential adaptive phases were identified in the plan for this segment. The overall themes of these phases are to narrow and eventually relocate the proposed bikeway corridor over time with the goal of keeping this mobility corridor in close, but safe, distance from the ocean to maximize coastal views from the trails.

Solamar Drive: One potential adaptive phase was identified in the plan for this segment with multiple options.

The overall themes are to maximize the use and function of the roundabout and explore multi-benefit opportunities for enhanced access. One option is to evaluate erosion control and cliff stabilization methods which could be pursued in conjunction with a beach access stairway at this location. Another option would be to change the proposed roundabout to a signal to regain some space and distance from the cliff erosion hazard.

Las Encinas Creek: Adaptive pathways for this segment hinge on which project option is pursued (i.e., Phased Adaptation or Retreat Now). Since the Retreat Now option is built to a year 2120 resilient location, an adaptive pathway was not developed for that option. The proposed adaptive pathway for the Phased Adaptation option includes two triggers that would signal the need to begin the planning and implementation of the removal of the southbound roadway and shifting active transportation users to a new boardwalk or the complete street roadway and bridge. Triggers identified include rock revetment armoring integrity and flood frequency.

Island Way: Given that the proposed roadway is inland of State Parks campground facilities and significantly inland from the cliff edge, an adaptive pathway framework was not developed for this segment. Instead, it is recommended that the city continues to coordinate with State Parks regarding their plans to adapt these facilities.

It is important to note that the project is still in the preliminary engineering phase. Thus, this plan is based upon a conceptual understanding of how particular assets and features throughout the project are situated. This plan may require revision as additional engineering details are refined.

South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan ghd.com ➔ The Power of Commitment
Attachment E

STATE OF CALIFORNIA-NATURAL RESOURCES AGENCY GAVIN NEWSOM, GOVERNOR

CALIFORNIA COASTAL COMMISSION

SAN DIEGO DISTRICT OFFICE
7575 METROPOLITAN DRIVE, SUITE 103
SAN DIEGO, CA 92108-4402
VOICE (619) 767-2370
FAX (619) 767-2384
April 15, 2024
Brandon Miles
1635 Faraday Ave.

Carlsbad, CA 92008
Re: Coastal Development Permit Application #6-16-0450-A2 Dear Mr. Miles:

Commission staff has reviewed the above cited permit amendment application to extend the approval for an additional five years in order to complete studies, design, permitting and identify a funding source to complete the special conditions outlined in the underlying permit for the approximately 520 linear foot rock revetment located on the beach on the west side of southbound Carlsbad Blvd, north of Encinas Creek in Carlsbad. Commission staff determined that additional information is necessary in order to properly review this application and schedule it for public hearing. Please provide the following:

1. Hazards Management Plan for Carlsbad Blvd
As you are aware, Special Condition #1 (b) required the submittal of a long-term Hazards Management Plan for Carlsbad Boulevard by March 14, 2024. We appreciate that a plan (South Carlsbad Climate Adaptation Project Long-Term Master Plan/ Adaptive Management Plan, February 28, 2024) was provided as part of this amendment submittal.

As required by the underlying permit CDP No. 6-16-0450, this report:
"shall incorporate measures to adapt to sea level rise over time and provide for the long term protection and provision of public improvements, coastal access, public opportunities for coastal recreation, public views and coastal resources, including beach and shoreline habitat (measures may include, but need not be limited to, phased implementation of beach nourishment, soft protection, managed retreat, focused or small-scale armoring) and a time line or event driven schedule for implementation of the plan. The plan shall evaluate and consider all potential constraints, including geotechnical and engineering constraints; potential phasing options with timelines; project costs for the preferred project and alternatives; and potential funding options. The plan shall be submitted with documentation sufficient to support all analyses, methodologies, and conclusions."
The long-term Hazards Management Plan for Carlsbad Boulevard provided does not in its' current form fully address these prescriptive requirements including but not limited to protection and provision of public views, beach and shoreline habitat.

In addition, the plan does not appear to include a timeline or event driven schedule for implementation of the plan. We understand that there may be additional revisions to this plan as part of on-going efforts to relocate Carlsbad Blvd. Please April 15, 2024

Page 2 ends

provide a project timeline completion to achieve the above outlined requirements for the long-term Hazards Management Plan for Carlsbad Boulevard. Please note that the Commission's technical staff are still reviewing the report and may have additional questions.

2. Alternatives Analysis/Mitigation
As stated in the underlying permit CDP No. 6-16-0450, Special Condition 1 (c) requires an alternatives analysis report to be submitted if the permittee proposes to retain any portion the shoreline protection beyond the six year authorization period.

The special condition specifically requires:
"If the permittee proposes to retain any portion the shoreline protection beyond the six year authorization period [ ... ]the permittee is required to include in the permit application an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP. The permittee must also include mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial five year period of authorization.

Since this amendment application requests an additional five year authorization please provide a report which must include an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP.

In addition, Special Condition #1 (c) requires mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial six year period of authorization.

Therefore, because the revetment will remain beyond the initial six year authorization please provide the report as outlined in Special Condition 1 (c) of the underlying permit. As mentioned previously, Commission technical staff are still reviewing the report and they may seek additional clarification regarding the submitted report.
2 April 15, 2024

Page 3 ends

3. Appendix B
Appendix B must be completed and signed by the City of Carlsbad Planning Department. Please submit a completed version of the document, which should include local approval of the project with local staff signature and a California Environmental Quality Act determination.

Please do not limit your submittal to the above mentioned items. You may submit any information which you feel may help Commission staff gain a clear understanding of the scope of your project. When all required information is received, reviewed by staff and found to be adequate to analyze the project, your application will be filed and scheduled on the next available Commission agenda. If you have any questions, please feel free to email me at [email protected].

Sincerely,
Chelsea Jander
Coastal Planner
3 Attachment F

STATE OF CALIFORNIA-NATURAL RESOURCES AGENCY GAVIN NEWSOM, GOVERNOR

CALIFORNIA COASTAL COMMISSION

SAN DIEGO DISTRICT OFFICE
7575 METROPOLITAN DRIVE, SUITE 103
SAN DIEGO, CA 92108-4402
VOICE (619) 767-2370
FAX (619) 767-2384
April 15, 2024
Brandon Miles
1635 Faraday Ave.

Carlsbad, CA 92008
Re: Coastal Development Permit Application #6-16-0450-A2 Dear Mr. Miles:

Page 2 ends

Page 3 ends

Sincerely,
Chelsea Jander
Coastal Planner
3 Chelsea Jander
San Diego District Office
7575 Metropolitan Drive, Suite 103
San Diego, CA 92108-4402
Ms. Jander,
As a follow-up to the City of Carlsbad amendment request submitted on March 14, 2024, we received the request for additional information on April 15, 2024. In addition, we met on April 29, 2024, to discuss further the request for an additional five years in order to complete studies, design, permitting and identify a funding source to complete the special conditions outlined in the underlying permit for the approximately 520 linear foot rock revetment located on the beach on the west side of southbound Carlsbad Blvd, north of Encinas Creek in Carlsbad.

Thank you for the time to provide additional information needed for Amendment 2. The City of Carlsbad received the following comments and request for additional information with city responses below:

1. Hazards Management Plan for Carlsbad Blvd
As you are aware, Special Condition #l(b) required the submittal of a long-term Hazards Management Plan for Carlsbad Boulevard by March 14, 2024. We appreciate that a plan (South Carlsbad Climate Adaptation Project Long-Term Master Plan/ Adaptive Management Plan, February 28, 2024) was provided as part of this amendment submittal.

The plan shall be submitted with documentation sufficient to support all analyses, methodologies, and conclusions."
The long-term Hazards Management Plan for Carlsbad Boulevard provided does not in its' current form fully address these prescriptive requirements including but not limited to protection and provision of public views, beach and shoreline habitat. In addition, the plan does not appear to include a timeline or event driven schedule for implementation of the plan. We understand that there may be additional revisions to this plan as part of on-going efforts to relocate Carlsbad Blvd. Please provide a project timeline completion to achieve the above outlined requirements for the long-term Hazards Management Plan for Carlsbad Boulevard.

Please note that the Commission's technical staff are still reviewing the report and may have additional questions.

City Response:

The city has applied for eight grant opportunities to fund this effort. Unfortunately, we have not been successful. The city plans to continue to apply for funding but approximate total costs to implement what is described in the plan is $279 million. The timeline and schedule of implementation will depend on receipt of funding. Below is the project webpage that provides the progress to date.
https://www.carlsbadca.gov/departments/public-works/projects/our-coastline/south carlsbad-coastline

2. Alternatives Analysis/Mitigation
As stated in the underlying permit CDP No. 6-16-0450, Special Condition l(c) requires an alternatives analysis report to be submitted if the permittee proposes to retain any portion the shoreline protection beyond the six year authorization period. The special condition specifically requires:
"If the permittee proposes to retain any portion the shoreline protection beyond the six year authorization period [ ... ] the permittee is required to include in the permit application an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP. The permittee must also include mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial five year period of authorization." Since this amendment application requests an additional five year authorization please provide a report which must include an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP.

In addition, Special Condition #l(c) requires mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial six year period of authorization. Therefore, because the revetment will remain beyond the initial six year authorization please provide the report as outlined in Special Condition l(c) of the underlying permit. As mentioned previously, Commission technical staff are still reviewing the report and they may seek additional clarification regarding the submitted report.

City Response:

Attached is the Alternative Analysis Report -Las Encinas Revetment, dated May 2017 by Moffat Nichol that was previously submitted with the CDP application (Attachment 2).

City Response:

Updated Appendix Bis attached for your consideration (Attachment 3}.

Sincerely,
Brandon Miles, PE, TE, QSD
Project Manager
Public Works Branch
Transportation Engineering Division
City of Carlsbad
1635 Faraday Ave.

Carlsbad, CA 92008
www.carlsbadca.gov I [email protected]
442-339-2745 (office) I 760.579.3321 (mobile}
Attachments:

1. Coastal Commission Letter 6-16-0450 (dated 4-15-2024}

2. Alternatives Analysis Report

3. Appendix B
cc: Paz Gomex, Deputy City Manager
Tom Frank, Transportation Director/City Engineer
Eric Lardy, Assistant Director of Community Development

FINAL ALTERNATIVES ANALYSIS
REPORT

LAS ENCINAS REVETMENT
Prepared by:
moffatt & nicl10I
1660 Hotel Circle North, Suite 500
San Diego, CA 92108
(619) 220-6050 •
Prepared for:
( City of
Carlsbad
California
City of Carlsbad
1635 Faraday Avenue
Carlsbad, California 92008
May 2017
(cityor
Carlsbad
(JI do If'\ I.! Final .·llternalives Ana(vsis Report: Las Encinas Revetment

TABLE OF CONTENTS

1. INTRODUCTION ............................................................................................................................. 1

2. EXISTING CONDITIONS .............................................................................................................. 3

2.1. CARLSBADBOULEVARD .................................................................................................... 3

2.2. LAS ENCINAS REVETMENT ................................................................................................ 4

2.3. SOUTH CARLSBAD STATE BEACH ................................................................................... 5

2.4. PUBLIC ACCESS WAYS ........................................................................................................ 9

2.5. AESTHETICS ........................................................................................................................... 9

2.6. LAS ENCINAS CREEK ........................................................................................................... 9

2.7. SEA LEVEL RISE .................................................................................................................... 9

3. ALTERNATIVES ANALYSIS ...................................................................................................... 10

3.1. NO REVETMENT, CLOSURE OF MOST SEAWARD LANE ........................................... 10

3.2. NO REVETMENT, SHTFT ALL TRAFFIC TO NORTHBOUND ALIGNMENT ............... 10

3.3. HARD PROTECTION STRATEGIES.; ................................................................................. 11

3.3.1. RAISE EXISTING REVETMENT. ........................................................................................ 11

3.3.2. CONSTRUCT SEA WALL......... . ................................................................................. 11

3.4. SOFT PROTECTION STRA TEGlES .................................................................................... 12

3.5. OTHER ALTERNATIVES .................................................................................................... 13

3.6. ALTERNATIVES ELIMINATED FROM ANALYSIS ........................................................ 13

3.6./. STOR.Jvf WATER 1\JANAGEMENT STRATEGIES, EXISTING TRAFFIC CONFIGURATION......................................... . ........................................................... 13

4. ALTERNATIVES COMPARISON ............................................................................................... 14

5. CONCLUSIONS ............................................................................................................................. 18

6. REFERENCES ................................................................................................................................ 19 APPENDIX A. Exhibits ............................................................................................................................ 20 APPENDIX B. Las Encinas Revetment As-Builts ................................................................................. 21 .lp,i/2()/7
{"City of
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( d I 1 ( 0 I II I ,I

FIGURES
Final .·lltematives Analysis Report. las Encinas Revetment Figure 1.1. Wave Runup in the Project Area (December 24, 2015) .............................................................. 2 Figure 1.2. Emergency Revetment Construction .......................................................................................... 2 Figure 2.1. Overside Drain ............................................................................................................................ 4 Figure 2.2. Shallow V-Ditch & Inlet (Left) and Asphalt Dike (Right) ......................................................... 4 Figure 2.3. Bluff Cracking within the Project Area ...................................................................................... 5 Figure 2.4. Beach Width Change within the Proejct Area ............................................................................ 7 Figure 2.5. South Carlsbad State Beach, November 2011 (Pre-RBSP II, CFC 2015) .................................. 8 Figure 2.6. South Carlsbad State Beach, December 2012 (1 Month Post-RBSP II, CFC 2015) .................. 8 Figure 3 .1. Seawall along Carlsbad Boulevard at Agua Hedionda Lagoon ................................................ 12 Figure 3.2. Winter Berm in Seal Beach, California .................................................................................... 13 TABLES
Table 2-1. Beach Nourishment & Sand Bypassing, South Carlsbad State Beach (CFC 2016, CFC 2017) ................................................................................................................................... 6 Table 2-2.2012 National Research Council Sea Level Rise Scenarios ........................................................ 9 Table 4-1. Alternatives Swn1nary ............................................................................................................... 15 AJ)l'il ]()! 7 II
(_ City of
Carlsbad
L .J I If or " I J

1. INTRODUCTION
Final .·l/ternati1•es Anu(vsis Report: Las Encinas Revetment This report addresses the California Coastal Commission (CCC) request for viable alternatives to address erosion, stabilization, and access along a low-lying segment of southbound Carlsbad Boulevard near Las Encinas Creek in the City of Carlsbad ( city). This report was prepared to satisfy Special Conditions 3 and 5 of emergency permit number G-6-15-0049. The 2015/2016 El Nifio winter produced a succession of large wave events that resulted in coastal erosion of the bluff and damage to the southbound Carlsbad Boulevard roadway. CCC emergency permit number G-6-15-0049 (December 29, 2015) and Army Corps of Engineers (ACOE) and Regional Water Quality Control Board (RWQCB) permit number R9-2015-0214 (January 2016) were subsequently established to ensure safety, and protect life and assets. The city constructed 270 feet of revetment under these permits. An additional 250 ft of temporary revetment was constructed in March 2016 under an ACOE emergency permit (R9-2016-0108); and the city has requested the CCC to provide an after-the-fact approval for a 5-year term.

The Project Area is defined by Island Way to the south and Solamar Drive (entrance to Hilton Garden Inn) to the 1101th (Exhibit Al of Appendix A). Wave energy and coastal processes drive erosion along this reach and have established a narrow beach backed by a low bluff subject to wave overtopping, erosion, and slope instabilities. The bluff has been stabilized with multiple segments of rock revetment (totaling 1,270 ft) to maintain safe access along this reach, as depicted in Exhibit A2 and described below:
• 2009 Revetment -The first segment comprises 750 linear feet (If) ofrock revetment permitted as a part of the 2009 Las Encinas Bridge replacement project. • 2015 Revetment-The second segment comprises 270 If of rock revetment constructed under CCC emergency permit G-6-15-0049 and ACOE/RWQCB Regional General Permit (RGP) R9-2015- 0214. The 2015/2016 El Nifio winter produced a succession of large wave events, some of which coincided with high tides. A series of these events resulted in damage to southbound Carlsbad Boulevard near Las Encinas Creek on December 11, 2015 (Figure 1.1 ). Erosion from these El Nifio events prompted the city to extend the existing revetment northward along this reach of roadway to stabilize the bluff (Figure 1.2). The seaward lane of Carlsbad Boulevard was closed until the roadway was stabilized. The city declared a local emergency on December 15, 2015 in response to damage from these storms.
• 2016 Revetment -The third segment comprises 250 If of temporary rock revetment constructed in March 2016 under ACOE emergency permit R9-2016-0108, but without a CCC emergency permit.

El Nino storm events spurred the Governor of California to declare a state of emergency for many coastal counties, including San Diego on February 29, 2016. In March 2016, storm damage ensued n01thward of the 2015 Revetment. A 250-ft emergency revetment was constructed of2-to 4-ton rock, consistent with the design of the existing rock revetment to the south. Construction of the emergency revetment finished in May 2016. An approved federal damage assessment was obtained from Caltrans in August 2016. Caltrans received a federal categorical exclusion for the work at that time.

The city requests that the temporary revetment protection with no change be permitted for a period of 5 years while the city develops a long-term management plan for the roadway. The long-term management plan would consider the options presented in this report and would be vetted through the city's public process prior to making a final decision. As part of the June 8, 2016 non-filing letter, the CCC requested an Alternatives Analysis repo1t for the unpermitted revetment prior to consideration of a 5-yr permit extension.

This Alternatives Analysis report describes potential alternatives to address erosion in the Project Area along with associated impacts to public access and coastal resources.

April 2(/f 7
{City of
Carlsbad
( d I If o / 11 I d
.-lpril 2017
Final .·l/ternatives Analysis Report: Las Encinas Revetment FIGURE 1.1. WAVE RUNUP IN THE PROJECT AREA (DECEMBER 24, 2015) FIGURE 1.2. EMERGENCY REVETMENT CONSTRUCTION
J
(city of
Carlsbad
C<1lifornl.i

2. EXISTING CONDITIONS
Final .-1 l!ernatives A na~vsis Report. Las Encinas Revetment The existing conditions within the Project Area are described in this section.

2.1. CARLSBAD BOULEY ARD
The undeveloped reach of Carlsbad Boulevard between Solamar Drive (Hilton Garden Inn intersection) and Island Way is a prominent road within the city used for daily commuting, recreation, beach access, and emergency evacuation. Carlsbad Boulevard is classified as a Coastal Route. Within the Project Area, the nmihbound and southbound lanes are separated by a vegetated open space varying in width from 25-200 feet and follow different alignments. Carlsbad Boulevard provides two 10-foot traffic lanes in each direction with shoulders on either side; a class II bicycle lane is incorporated in the shoulder of the outside lane and separated from the traveled way by a 4-foot striped buffer. The focus of this report is on a low lying reach of the southbound alignment, which runs along the bluff top adjacent to South Carlsbad State Beach. The southbound alignment in some places has only a 5-foot width from the roadway to the bluff edge and has a minimum elevation of about 15 feet NGVD29 within the Project Area. The northbound alignment is fatiher inland (setback 150-250 feet from the bluff top) and has a minimum elevation of about 35 feet NGVD29 (Exhibit A3).

Roadway drainage along Carlsbad Boulevard is achieved through the use of dikes (similar to curbs), overdrains, shallow v-ditches, and drainage inlets. Stmm water that falls on southbound Carlsbad Boulevard runs off to the outside edge of each lane due to the roadway slope. Runoff is concentrated along the landward shoulder in a shallow v-ditch that drains to an inlet. A continuous dike runs along the shoulder of the most seaward lane beginning at a high point near the intersection of south Carlsbad Boulevard and Solamar Drive, then extends south, and downgrade to a series of overside drains at a low point located near the Las Encinas Creek Bridge. The dike conveys runoff from the seaward lane of Carlsbad Boulevard along the shoulder to the overside drains, preventing storm water from running off to non-stabilized potiions of the bluff. The overside drains near Las Encinas Creek are lined with asphalt on the bluff top and riprap on the bluff face. Drainage facilities on nmihbound Carlsbad Boulevard are similar with shallow v-ditches and an inlet along the landward shoulder, and a dike and overdrain along down sloping reaches of the seaward shoulder. These drainage facilities are included in Figure 2.1 and Figure 2.2. Project Area topography is shown in Exhibit A3.
.-/;xii 2()/7 3
{"City or
Carlsbad
l d I 1 ( 0 I n I d Final Alternatives Analysis Report: Las Encinas Revetment FIGURE 2.1. OVERSIDE DRAIN
FIGURE 2.2. SHALLOW V-DITCH & INLET (LEFT) AND ASPHALT DIKE (RIGHT)

2.2. LAS ENCINAS REVETMENT
Erosion and bluff instabilities along southbound Carlsbad Boulevard prompted the need for the Las Encinas revetment. Slope stabilization began in 2009 and has continued through 2016. This was achieved with a rock revetment, built incrementally in three phases. The current extent of the Las Encinas revetment spans a total of 1,270 linear feet. Revetment lengths are derived from as-built plans for the Las Encinas revetment, provided in Appendix B.

The most recent reach of the revetment was constructed with 2-to 4-ton stone underlain by geotextile fabric at a slope of 1.5: 1 (H:V). A geotechnical evaluation of coastal bluff stability within the Project Area was .lpril 20/ 7 -I
(Cityo[
Carlsbad
L cl 1 if O Ill I ,1
Final Alternatives Analysis Report: Las Encinas Reve/111ent conducted in August 2016 to assess the slope stability of the soils for pre-revetment and post-revetment conditions. The rep01t found that the bluffs, generally composed of consolidated silty-sand, did not provide adequate static and seismic gross factors-of-safety against failure in the pre-revetment condition. Coastal bluff slope failures had previously occurred and were expected to continue if the bluff remained unprotected. Surficial stresses (fissures and cracking) were observed in both the bluffs and the roadway (Figure 2.3). If revetment construction did not occur, fmther erosion and slope failures would put the street right of way in imminent danger of collapse. Analysis of the slope with the revetment found adequate static and seismic gross factors-of-safety against failure (GSI 2016).

FIGURE 2.3. BLUFF CRACKING WITHIN THE PROJECT AREA

2.3. SOUTH CARLSBAD STATE BEACH
South Carlsbad State .Beach is a California State Park (CSP) owned beach, located on the seaward edge of the Project Area. The beach provides a buffer between southbound Carlsbad Boulevard and the ocean.

Beach monitoring at South Carlsbad State Beach has been performed bi-annually by Coastal Frontiers Corporation (CFC) since 1987. Two beach profile locations, CB-0760 and CB-0775, are located south and n01th of the Project Area, respectively (Exhibit A4). Based on this dataset, the average beach width for Carlsbad Beach is 115 feet.

On a seasonal scale, this beach follows a general trend of erosion in the winter and accretion in the summer.

However, city beaches are managed through the bypassing of sediment up coast (i.e., Agua Hedionda Lagoon) and beach nourishment projects (Table 2-1 ). Sand bypassing is long-term dredging of littoral sand that deposits in lagoons and navigation channels, and placement of the sand on downcoast beaches to restore longshore sediment transport. It differs from beach nourishment in that it bypasses existing littoral sediment .-lpril 2() 17 5
(cityo[
Carlsbad
( I I i ( Cl I n I ,I Final .·lllernalives Analysis Reporl: Las Encinas Reve/111enl around lagoons/harbors, as opposed to bringing in a new source of sediment from outside the littoral zone for beach nourishment.

Sand bypassing also occurs south of the Project Area at Batiquitos Lagoon; however, due to coastal processes along the San Diego coast, net sediment transp01t is generally directed southward, and this sand likely does not appreciably enhance South Carlsbad State Beach widths.

South Carlsbad State Beach has been the recipient of direct beach nourishment effo1ts through the Batiquitos Lagoon Enhancement Project in 1995 (1.25 million cy), the San Diego Regional Beach Sand Project I (RBSP I) in 2001 (158,000 cy), and the San Diego Regional Beach Sand Project II (RBSP II) in 2012 (141,000 cy). These eff01ts deposited a total of 1,549,000 cy of sediment on South Carlsbad State Beach.

Nourishment events are evident in the beach width change data, as shown in Exhibit A4. Since RBSP II in 2012, beach width has narrowed to just below the average, approximately 100 feet. Pre-and post-RB SP II conditions can be seen in Figure 2.5 and Figure 2.6, where the change in location of the high tide line is visible at the transition from light to dark sand.

TABLE 2-1. BEACH NOURISHMENT & SAND BYPASSING, SOUTH CARLSBAD STATE BEACH (CFC 2016, CFC 2017) Project Date Sediment Source Placement Location Sediment Quantity (cy)
Batiquitos Lagoon 1995 Batiquitos South Carlsbad 1,250,000 Enhancement Project Lagoon RBSPI Summer 2001 Offshore South Carlsbad 158,000
RBSP II Fall 2012 SO-5 Offshore South Carlsbad 141,000
1994 Carlsbad 159,000
1996 Carlsbad 443,000
1997 Carlsbad 197,000
1998* Carlsbad 560,000
Agua Hedionda 1999 Carlsbad 203,000
2001 Agua Hedionda Carlsbad 429,000 Lagoon Bypassing 2003 Lagoon Carlsbad 337,000 Project 2005 Carlsbad 375,000 2007 Carlsbad 335,000
2009 Carlsbad 299,000
2011 Carlsbad 226,000
2015 Carlsbad 295,000
* Agua Hedionda Facilities Modification project was not a part of the standard sand bypassing. .-lpril 2() 17 6
:,._
~I I
n
" ::::.: Mean Sea Level Beach W idth (feet) !?: ,,...., -"-n
'v ~ §
~
8 "' - ·
c::, 0 0 )!I g~
'--l o..~
Fall 1987
Spring 1996
Fall 1996
Spring 1997
Fall 1997
Spring 1998
Fall 1998
Spring 1999
Fall 1999
Spring 2000
31 Fall 2000
Cl Spring 2001
~ ~ ~ N Fall 2001
;... Spring 2002
~ Fall 2002
"' > Spring 2003 (")
=
~ Fall 2003
8 Spri ng 2004 .., = Fall 200 4
(j
= Spri ng 2005
> z Fall 2005 Cl
"' Spring 200 6 ::;;
=i Fall 2006
~ Spring 2007 ..,
Fall 2007 gi
"C Spring 2008
:0
~ Fall 2008 -,,
'-<
Spring 2009
:::-
q §_
~
Fall 2009 -'-
> Spring 2010 [
Fall 2010
§.
::·
" Spring 2011 "'
Fall 2011 ::-
:S ,:::-
Spring 2012 ;;o
I
:.:.:

Fall 2012
OJ z;·
VI ::s,
--0 n .g Spring 2013 =
OJ
6 ~ Fall 2013 --.J
(J) r-
Spring 2014 0 S.

Fall 2014
I
~ ;;
Spring 2015 :::· n :S
Fall 2015
CD
"' 6 :,:,
Spring 2016
--.J '.,
--.J
~ Fall 2016
V,
'-' I I ~
l_ City of
Carlsbad
(. J It ( O I 11 I J Final Alternatives rlnalysis Report: Las Encinas Revet111ent FIGURE 2.5. SOUTH CARLSBAD STATE BEACH, NOVEMBER 2011 (PRE-RBSP II, CFC 2015) FIGURE 2.6. SOUTH CARLSBAD STATE BEACH, DECEMBER 2012 (1 MONTH POST-RBSP II, CFC 2015) April 1() I 7
(city or
Carlsbad
( ,, I 1 ( O I II I ,1
Final Alternatives Ana(vsis Report: Las Encinas Revetment

2.4. PUBLIC ACCESS WAYS
Public access ways in the Project Area consist of a single lateral trail near the parking entrance for South Carlsbad State Beach. No formal pedestrian sidewalk exists in the Project Area. Any other beach access points, such as foot-worn pathways that cut over the Las Encinas revetment or in areas north of the revetment at other non-stabilized bluff points, are informal, unregulated, and not maintained. These informal access points are likely used by beach users who park along the bluff top near Solamar Drive at the north end of the Project Area.

2.5. AESTHETICS
The stretch of Carlsbad Boulevard within the Project Area is one of only a few open space areas along the city's coastline. At its northern end, the open space begins at Terramar Point and continues south along Carlsbad Boulevard until the South Carlsbad State Beach campground (near Island Way). Varying topography in the Project Area creates unique visual aesthetics from the north and southbound lanes.

Southbound Carlsbad Boulevard runs along the bluff top and generally has unobstructed beach and ocean views for road users along the Project Area. No1thbound Carlsbad Boulevard is fa1ther inland and provides a higher vantage point but limited visibility of the ocean to road users due to the topography and roadway alignment. Road users traveling in either direction can also view the low-lying wetlands near Las Encinas Creek.

2.6. LAS ENCTNAS CREEK
The creek runs tlu·ough the middle of the project site between the no1thbound and southbound alignment of Carlsbad Boulevard. Las Encinas Creek is pait of the Canyon de las Las Encinas watershed, which is a small watershed (~3,500 acres) within Carlsbad. Las Encinas Creek Watershed extends approximately 2.4 miles inland adjacent to Palomar Airport Road. The mouth of Las Encinas Creek naturally closes as a result of a sand and/or cobble berm formed by coastal processes. Significant rain events will open the creek mouth to the ocean.

2.7. SEA LEVEL RISE
Sea level rise threatens to exacerbate coastal hazards affecting this roadway by increasing the frequency of roadway flooding and erosion, which can undermine the road. Coastal hazards affecting this area are discussed in Section 2.2. Based on best available science for the region, sea levels are predicted to rise by

1.5 to 5.5 feet in the Project Area by year 2100. Relative sea level projections for Southern California are shown in Table 2-2.

TABLE 2-2.2012 NATIONAL RESEARCH COUNCIL SEA LEVEL RISE SCENARIOS 2012 National Research Council Sea Level Rise Projections Year Uncertainty Projection (ft) (ft, +/-) Low Range (ft) High Range (ft) 2050 0.9 0.3 0.4 2.0
2100 3.1 0.8 1.5 5.5
A city-wide sea level rise vulnerability assessment has been prepared for Carlsbad (M&N 2016). The study discussed the site's high sensitivity to sea level rise due to the consequences associated with transpmtation interruptions and repair costs. Given the results of the modeling and analysis, the roadway was assigned a moderate vulnerability by 2050 and a high vulnerability score by 2100. The study recommended that landward relocation of the southbound lane be considered at the time of a planned future capital improvement, or as pa1t ofrepetitive future emergency repairs.

AprilH!l7 9
(_City of
Carlsbad
c JI , r o r n 1 .a Final .•llternalives Analysis Report: Las Encinas Reve/111ent

3. ALTERNATIVESANALYSIS
This section describes potential alternatives that can be implemented along southbound Carlsbad Boulevard to address hazards. A description of each alternative as well as a discussion of potential primary and secondary impacts is provided in this section. Primary impacts are those that occur as a direct result of the project while secondary impacts are those that may not be fully considered at the time of the project and occur later. An example of a secondary impact would be the eventual loss of sandy beach if shoreline protection strategies are implemented with rising sea levels and no other management actions (like beach nourishment).

3.1. NO REVETMENT, CLOSURE OF MOST SEAWARD LANE
For this alternative, po11ions of the revetment that are not essential to bridge protection are removed and the most seaward lane of southbound Carlsbad Boulevard is closed to traffic. All southbound vehicular traffic would be conveyed by the easternmost lane. The road shoulder and bike lane would be shifted over to the decommissioned (seaward) lane. Assuming the current lane and shoulder widths are maintained, 10 feet of existing roadway will be available for decommissioning and serve as a buffer for informal access and parking, continued bluff retreat, erosion and flooding from wave runup.

This alternative is a shmi-term solution. Without the revetment, the bluff top carrying Carlsbad Boulevard will continue to retreat inland. Bluff top erosion along this reach was documented in the 2016 bluff stability report, which identified bluff and pavement surficial stresses (fissures and cracking) along with slope failures (GSI 2016). The unpaved bluff top adjacent to the road ranges from 5-15 feet in width along this reach. The remaining unpaved bluff is variable in width and surficial stresses extending to the pavement are documented. Therefore, when the revetment is removed, the excess shoulder should be closed to traffic and the pavement removed to prevent sections of the roadway from sloughing onto the adjacent beach as the bluff erodes. Portions of the revetment that protect the bridge abutments and foundations must remain in place as they are crucial to bridge stability.

3.2. NO REVETMENT, SHIFT ALL TRAFFIC TO NORTHBOUND ALIGNMENT This alternative shifts all traffic to the nmihbound alignment of Carlsbad Boulevard between Solamar Drive and Island Way. Pmiions of the revetment that are not essential to bridge protection are assumed to be removed and bluff erosion would continue to undermine the existing southbound lanes along this reach.

Traffic would be consolidated to a single nmihbound lane and single southbound lane between the Solamar Drive and Island Way intersections. Intersection reconfiguration would be required including additional paving in the vicinity of the Solamar Drive intersection to transition southbound traffic to the new alignment. A similar transition and reconfiguration would be required in the vicinity of the Island Way intersection, returning southbound traffic to the existing alignment. Assuming current lane widths will be maintained, adequate roadway width exists along the nmihbound aligmnent to accommodate an undivided two lane highway ( one lane in each direction) with a bike lane incorporated in the shoulder for both directions.

In this alternative, the existing lanes of southbound Carlsbad Boulevard would be closed to through traffic.

In the immediate short-term future, this road could be used for alternative purposes, which may include multi use trails, bike lanes, beach access, and parking. As erosion progresses, unprotected portions of the road will become undermined by bluff erosion and require pmiions of the road to be decommissioned. With regular maintenance, the existing revetment could remain in place and preserve alternate uses along the southbound alignment for a longer period of time.

If the existing traffic configuration (2 lanes in each direction) is desired along the nmihbound aligmnent in the future, roadway widening will be necessary. The n011hbound alignment has an existing width of 40 feet and would need to be widened an additional 44 feet for a total road width of 84 feet to accommodate a April JOI 7 I()
(city of
Carlsbad
C ,, I, f o, n I ,1
Fined .·lltematives Analysis Report: Las Encinas Revet111e11/ median, 2 northbound lanes, 2 southbound lanes, shoulders and bike lanes. Roadway widening in the Project Area would require special consideration of environmental resources, especially in the vicinity of Las Encinas Creek. Road widening near the creek could be achieved by additional fill, a bridge, or a combination of both that may affect the creek. Other areas could be widened using cut and fill methods and may require retaining walls.

3.3. HARD PROTECTION STRA TEGTES
Hard protection strategies that may be incorporated at this site include the use ofrevetments and seawalls, or a combination of both. In the past, geotechnical instabilities have prompted the installation of a rock revetment along southbound Carlsbad Boulevard, as described in Section 2.2. Two options were considered in this section to: raise the existing revetment and construct a new seawall. These alternatives are discussed below.

3.3.1. RAISE EXISTING REVETMENT
Revetments can be used to stabilize erodible slopes by providing an armor layer able to resist the erosive forces of wave energy. The existing revetment could be fortified and raised to provide additional bluff stability and protection from wave runup. Raising the revetment would provide additional height to the bluff top, but may slightly reduce the road width, and may encroach slightly seaward from the existing footprint. The road surface could either remain below the revetment crest for protection from wave runup, or could be raised with the revetment crest to reduce its vulnerability.

Revetment occupies a larger footprint on the beach than a seawall, described below. Revetment is typically less costly than a seawall, and can be repaired fairly easily. Revetment works primarily by wave dissipation within voids between rocks. If the revetment design does require a road width reduction, a lane may need to be dropped to maintain a bike lane in this direction.

3.3.2. CONSTRUCT SEAWALL
Seawalls are another hard protection strategy that may be implemented along southbound Carlsbad Boulevard. Although rock revetments have been used to stabilize the bluff, they may not completely protect the roadway from flooding if future ocean water levels rise as predicted. At this site, a vertical seawall could be constructed along the outside of southbound Carlsbad Boulevard. This application would be similar to the seawall constructed along a reach of Carlsbad Boulevard at Agua Hedionda Lagoon to prevent flooding of the sidewalk and roadway, as shown in Figure 3.1. Vertical seawalls can exacerbate beach erosion, and the bluff and beach seaward of the wall may be severely eroded without beach nourishment at South Carlsbad State Beach. Seawalls are fairly expensive compared to revetment, but occupy a smaller footprint and can more thoroughly protect backshore development by redirecting wave energy seaward. They tend to cause more coastal erosion than revetment. Seawalls simply reflect waves back to sea with little or no energy dissipation. Both hard structures will trigger "end effects" that consist of enhanced erosion at their endpoints that would need to be carefully addressed.

A seawall would preserve current roadway facilities for vehicles and bicycles along this reach. The city would include new beach access points and viewpoints (like seawall and street-side improvements between Pine Avenue and Tamarack Avenue) if this option were pursued.

Apri/l0/7 II
(cityot'
Carlsbad
( ,:JI If o t n I J Final ,·lltemalives Analysis Reporl: Las Encinas Reve/111e11/ FIGURE 3.1. SEAWALL ALONG CARLSBAD BOULEVARD AT AGUA HEDIONDA LAGOON

3.4. SOFT PROTECTION STRA TEGlES
Beach nourishment and winter sand dikes were considered for the project as soft protection strategies. Sand retention strategies could be employed in conjunction with beach nourishment to retain sand in place for a longer period of time. Retention structures consist of reefs, groins, and other structures to physically intercept waves and/or sand movement to result in building beaches. These alternatives are discussed in this section.

Beach nourishment rebuilds the existing beach, which provides a natural buffer to coastal assets from coastal storms. This buffer would help to preserve facilities for vehicles, bicycles, informal access and informal parking. Beach nourishment projects impo1t sand from offshore, lagoon or upland sources via dredge or truck. Past beach nourishments at this site have been successful in widening the beach. However, beach width gains last for a period of about 5 years, depending on conditions. Thus, frequent beach nourishment would be needed to provide effective protection of the site. Lagoon maintenance dredging projects in the city (i.e., Agua Hedionda and Batiquitos Lagoon) could provide a viable, frequent source of sand for this beach. Collaboration with lagoon managers would be needed to explore use of these materials.

With predicted increased water levels, greater amounts of sand would be needed for future beach nourishment projects in order to provide the same level of protection.

Winter sand dikes, or berms as they are more commonly known, provide flood defense to coastal assets from wave uprush and are common forms of protection in Southern California. Berms vary in height and width depending on site-specific vulnerabilities and considerations. A typical sand berm example is shown in Figure 3.2 below. The sand used to build these berms is typically derived from the foreshore beach zone and is commonly referred to as beach scraping. Berms are generally built in the winter (around Halloween or Thanksgiving) and lowered in the spring or summer (around Easter or Memorial Day), after coastal storm vulnerabilities decrease. Regular beach nourishment may be needed to ensure adequate sand exists to form a winter berm if it does not exist naturally.

April ](J/ 7 /2
(cityol'
Carlsbad
( ,ii I ( O I fl l d
Final A/1ernalives Ana(vsis Reporl: Las Encinas Revetmenl FIGURE 3.2. WINTER BERM IN SEAL BEACH, CALIFORNIA
A nearshore reef may reduce the potential for erosion of the beach and bluffs by dissipating wave energy, aiding in sand retention and promoting beach widening at South Carlsbad State Beach. Nearshore reefs are yet unproven designs to stabilize beaches in Southern California. A nearshore reef would require planning, engineering, and approvals prior to construction. Monitoring, maintenance and analysis after construction would also likely be necessary.

3.5. OTHERALTERNATIVES
Additional alternatives do exist to address erosion challenges along this reach and have been listed below for consideration. Additional analysis will be provided if the city is interested in advancing these options at a later time.
• Hybrid Options-Combinations of protection strategies above (e.g., combine armoring with beach nourishment). SANDAG cost analyses showed that beach nourishment combined with sand retention structures could be more economical than nourishment or structures alone over a 50-year period.
• Elevate Road on Causeway -Carry southbound Carlsbad Boulevard on a pile-suppotied structure.

Costs are very high for this option and would require an extensive bridge structure. 3 .6. ALTERNATIVES ELIMINATED FROM ANALYSIS
Alternatives that do not address erosion and access problems at the site were eliminated from the analysis.

Storm water management strategies currently in place are described below along with discussion of alternative storm water management strategies and their inapplicability.

3.6.1. STORM WATER MANAGEMENT STRATEGIES, EXISTfNG TRAFFIC CONFTGURA TION Storm water management strategies include conventional methods like stonn drains, gutters, and conveyance systems similar to those currently in place on Carlsbad Boulevard that direct concentrated April 2017 /]
(city or
Carlsbad
Ca 1 If o In Id Final Alternatives Analysis Report: Las Encinas Revetment runoff away from the roadway to surrounding areas and other drainage facilities. Alternative methods may also be used to manage storm water by incorporating low impact design features like bioswales and permeable pavement to reduce runoff, promote infiltration, and store runoff close to the source.

Storm water runoff along the southbound lanes of Carlsbad Boulevard is currently in a managed state through the use of conventional management strategies including dikes (similar to curbs), overside drains, shallow v-ditches, and drainage inlets, as described in Section 2.1. A continuous dike traverses the entire length of the revetment extension, preventing roadway runoff from flowing seaward of the shoulder and potentially eroding the bluff. A series of overside drains discharge concentrated runoff to Carlsbad State Beach and ultimately to the Pacific Ocean. Overside drains are typically lined with concrete, rock, or other materials at their point of discharge to prevent erosion. The overside drains near Las Encinas Creek are lined with asphalt on the bluff top and riprap on the bluff face. Replacing the overside drains with conventional inlet and storm drain systems is not feasible at this location due to space constraints and a small elevation gradient between the roadway and beach. Additionally, this type of system would require a beach outlet at the base of the bluff with riprap protection and would be subject to obstruction caused by sand and debris that may impede drainage.

Existing site conditions constrain the viability of incorporating low impact design features to manage storm water. Adequate space does not exist at the site to implement alternative storm water strategies like bioswales due to sloped vegetated land to the east and a narrow eroded bluff top to the west. Carlsbad Boulevard is classified as a major arterial (AECOM 2012) which characterizes the application ofpervious pavement as medium to high risk and is not recommended (Caltrans 2014). The potential for sediment to runoff, wash over, or be windblown on the pavement from erodible soil flanking the road and the adjacent beach makes the site a poor candidate for pervious pavement.

Existing storm water management strategies prevent roadway runoff from contributing to bluff erosion along Carlsbad Boulevard. Erosion along the bluff face is largely driven by coastal processes and geotechnical characteristics of the bluff, and erosion due to runoff is negligible. Storm water management systems should be maintained to ensure adequate roadway drainage and prevent runoff from potentially eroding unprotected portions of the bluff. Additional storm water management strategies are not feasible at the site and this alternative will not be included in the alternatives comparison.

4. ALTERNATIVES COMPARISON
The various alternatives considered above were compared based on impacts to transportation, natural resources and public access as well as initial order of magnitude cost (initial and life-cycle) and resiliency to sea level rise. These alternatives are compared in Table 4-1 below.

Items considered in the initial order of magnitude cost are outlined in the alternative description below.

Initial costs should be further studied for alternatives the city may wish to pursue.

The long-term management plan would consider the options presented in this report and would be vetted tlu-ough the city's public process prior to making a final decision. No specific alternative is recommended at this stage. Rather, the comparisons are presented to inform the city for future decision-making.

I -I
Crlkrla
Dcrcrlr1ion
lrril }11/l
Rcmo,·c Rcnlmcnl & Rclrcal Roadwa,-
Sh&hu Quo -£xi.din~ No Rc,•clmcnl -Clo1c
Rcnlmtnl Southbound Seaward Lane
Mnintnin rc,·etmcnl
ond roadway in plocc
,,i1h l11nercduction.

Rcp.iir und mainlllin
rock revetmcnt,11s
needed.
(Sl'Cllonl.l)
Rcmon~ rc,·etment not cssentiol
to bridge protection. Assume
removal of 500 CY.

Remove se;iwnrd lone to pro,·ide
a buffer for continued, bluff
retrcot, erosion. ond flooding
from w1ivc runup. Assume
removal of 18,000 SF of
roudway, rcploccmcnt of 1,500
LF of AC dike and rest.ripe
roadway.

No Rcn~tmcnl -Shin all
Trame lo Northbound
Allgrumnl (Sl'Cllon 3.?)
All traffic is shifted to the
northbound alignment of
Carlsbad 81\'d. between Solnmur
Dri\'e und lslnnd Way.

The southbound ulignmcnt is
subject to continued wn,·e runup,
bluff retreat, and erosion. The
southbound nlignment muy
relll!lin for nltemote uses in the
near tenn.

Assume removal of 1,000 CY of
revetment stone, demolish
bridge, reconfigure intersections
with trnnsition p.i,·ement
(nssume 10,000 SF), restripc
ro11dm1y and demolish
southbound rondway (nsrume
96,000 SF).

T,\111.E 4-1. ALTERNATIVES SU~l~IARY
Haard Pm1cctlon
R11hc Rc,·clmtnl (Sccllon
JA,I)
Add rock (500 CY) to raise
existing re\'etmcnt for odditioDlll
bluff stability nnd protection
from wave runup.

Seawall (Seclion J.4.?)
Rcplnce reYetment with o
,•crticnl seownll olong scnwnrd
edge of southbound Carlsbad
Bmile,urd. Assume reploccmcnl
of l ,500 LF of revetment ,,ith
seawall.

Rcmo,·c Rcn~lmml & lmplermnl Soft Prolccrlon (Secllon 3.5) Buch Nourbhmcnl Winier Berm
Rcmo,·e revetment not cs~nliul
to bridge prot~~;n (nssume 500 Construct n ,,inter berm fronting • the bluff using beach scraping
lmplemcnl n bench nourishment
program nt South Corlsbnd Stale
Bench. lmport npproximately
200,000 CY of sand c\'CI)' 5
years, contingent on bench
perform11m:c.

Nourishment could occur more
frequently 11s material becomes
O\'ailablc from nnnlllll lugoon
dredging projects.
techniques. Berm would be
lowered in the summer.

Contingent on aYoiloble sand to
form berm.

Remo,·c revetment not essential
to bridge protection (assume 500
CY).

Ncanho~Rttf
Install nearshorc reef to prolecl
project nren. Re\'etmcnt rock
rcpurposed for reef. Additional
rock \\ill be needed.

Remove rc,·etment nol essential
lo bridge protection (nssumc 500
CY).

Construction of three, offshore
reefs al maximum wnter depths
of -10 to -15 feet MLLW ond
periodic placement of 100,000
cy of sand for the purposes of
bench nourishment. The offshore
reefs would be composed of 2-
to 4-ton rock and would hove o
crest e]e,·11tion of +10 feet
MLLW.
15 Crilcrill
Trnn~purh1tion Impnch
Vbuallmpacb
Bench Width lmpaetJ
.IJ'r;/ 20/l
Sl.11.tus Quo -EJ:bting
Rcn:tment
Road users would be
subject to impacts of
wnvc mnup which may
tcmpomrily nood the
rond\\n}' nnd deposit
debris. Ro11d usersnre
sensiti\·e lo flooding
11nd debris which enn
result in congestion.

Flooding 11nd debris in
the ro11dwny would
occur more frequently
nswr1tcrle\'elsrise.

No visuo\ impacts
would result from
mnintniningthc exiting
condition.

Passive beach erosion
could be exncerba.ted in
medium to long tcnn
(if not combined with
frequent nourishment)
duetorc\·etment
footprint occupying
beach, 11nd potentially
from \\'Uves impacting
therc\"elmcnt.

Rcmon Rcnlmenl & Rctrellt Ruadi,·ay
No Rn-etmcnt • Cloie
Suuthbound ~awHnl L11nc
(Sl'CtlonJ.I)
This could be a short lcnn fix.

Potentinl impacts to traffic
congestion. City trnffic dntn
suggests thnt II single lune in
southbound direction m11y be
sufficient to con\·ey traffic along
this reach in the short-tenn. A
moredetniled trnffic studv is
needed. -
A bike lane would be maintnined
nlong the new ro11dway shoulder.

Informal 11ccess along this rc11ch
would diminish ns erosion
progresses.

Short tenn ro11dwny protection.

Tnn•e\ could become h11Zardous
to ro11d users along southbound
alignment in the future. May
result in future emergency
action.

No Rentmcnl ·Shinall
Tnffie to Northbound
All~menl (Section 3.2)
This would be II long,-tcrm fix.

Potential impacts lo traffic
congestion. City traffic dntn
suggests thnt II single lune in
each direction ffl!IY be sufficient
to com·ey lroflic along this reach
in the short-term. A more
detailed troffic study is needed.

Bike lanes would be
incorporated in the roadway
shoulder. Informal access along
the southbound alignment would
remain depending on the extent
of erosion.

The southbound alignment
could be used for altcmati\·c
purposes, which mny include
muiliusc trails. bike lanes, beach
access, nnd parking. As erosion
progresses, unprotected portions
of the ro11d will become
undermined by bluff erosion ond
require portions of the road to be
decommissioned.

Benefici11\ impacts to natural and
11esthetic resow-ccs nt South
Carlsbad Stale Bench us portions
Bcnefieiul impacts to natw-111 und of the bluffnrc restored to 11 nestheticresourcesat South natural state.

Carlsbad Stale Bench as portions
of the bluff are restored to 11
naturnlstnte.

Any inland regression or
sediment contribution from
unarmored bluffs would be
minor and unnoticc11ble over the
design life of this nltcmnli\'e.

Moderate aesthetic impacts to
road users as topography results
in \"aried ocean 1ie\1"S along the
northbound alignment which nre
partially obstructed compared to
the ocean Yiews nlong the
current southbound alignment.

Beaches may widen as the bluff
erodes and the beach is allowed
to mignl\e l11ndward.

Hard Prolcctlon
RKbe Re\"elmcnl (St-cllon
JA.l)
Beneficial impacts of
maintaining tm\"c] along the
southbound alignment. Potential
impacts to lranic congestion if 11
lnne must be dropped lo
accommodate the re,·elmcnt.

City trafficd.utn suggcststhnt 11
single lune in each direction mar
be sufficient to com·ey lrnffic
along this reneh in the short
tcnn A more detailed traffic
study is needed.

A bike lnne would be mnintnincd
along the roadway shoulder.
lnfoTffllll access may be
impacted revetment
encroachment.

Moderate to si~ficnnl
inundntion impacts in lhe long
tenn us increused \\1ltcr le\'els
due to sea level rise overtop und
penncate the rc\"etmcnt.

Significnnl impacts to nuturul
bluffs CO\"Cred by nnnoring.

Moderate aesthetic impacts to
road users from raised
revetment. Decre11sed ocean
,•iews.

Passive bench erosion could be
exacerbated in medium to Jong
tenn (if not combined with
frequent nourishment) due to
re\·etment footprint occupying
beach, und potentially from
\\"ll\"CS impacting the rc\·ctmcnt.

Seawall (Section J,.J,2)
Bcncficiulimp:actsof •
m11int11ining existing traffic
configuration.

The bike lune would be
maintnincd along the rondmiy
shoulder. lnform11I access along
this reach would exist between
the roudwny shoulder ond
seawall.

Significant impacts to natural
bluffs from scuwull.

Moderate aesthetic impacts to
road users from scuwnll which
would partially o~struct existing
Sea\\'Ull has smaller foolprint
than existing revetment lc11ding
to towel space gains in the short
tenn Passive and 11ctive beach
erosion could be cxuccrbutcd in
medium to long tenn (if not
combined \\ith frequent
nourishment) due lo \\'UVCS
imp.icting thesea\\'Ull.

Remove Re\·etnicnl & l1nplemenl Sofr Prolccllon (Sl'Ctlon J.5) Beach Nourishment
Beneficial impacts of
maintaining existing traffic
configuration.

The bike \11ne would be
maintained along the rondwny
shoulder. Current infonnnl
access conditions nlong this
reach would remain.

Wl'.l\"c runup mny periodically
flood ro11d1\1ly.

Beneficial impacts to nuturnl nnd
ncsthcticresourcesnsthe beach
is \\idcncd. Tcmpornr)' impacts
during construction.
13euch \\idths would increase.

Winter Berm
Bcncficialimp.ictsof
mnintnining existing traffic
configurotion in the ncur tenn.

Moderate to significunl
inundation impacts in the long
tcnnnsincrc11scdw11terle\·els
due lo sea lc\·el riscreochthe
roudm1y.

The bike June would be
maintained along the roud1\U)'
shoulder. Current infonnul
access conditions along this
reach would rem11in.

Wn,·c nmup mny pcriodicnlly
flood road11ay ifbenn is
breached.

VisU.11! impacts contingent on
benn height. Anticipated to be
minimnl.

Winier berm lessens "towel
space" by some 11mount
occupied by berm.

Bcncficinl impacts of
mnintnining existing trnOtc
configurution in the near tcnn
The bike l11nc would be
maintnined along the roadway
shoulder. Current informal
access conditions nlong this
reach would remain.

Moderate to significant
inundation impacts in the long
tenn as increased water \e\·els
due to sea le\·el riscre11ch the
road\\ny.

No ,·istwl impacts from
submerged reef.

Likely to have benefici11l
impacts to nearshore habitat and
beuch \\idth.
/(,
Rcmon~ Re,·clmcnl & RclrcAI R1mdm,:,· H11rtlProlcction
Crilcri11
PuhlicAcceulm11acts
Sen Lcnl Rlrc
Resiliency
Other Consldcn1tlon1
Appro:1:ill\l1k Design
Life
lnilinlCosl
(USD, million)•
20-Ycnr Lifrcyclc Cod
(USD, million)••
St11tu1 Quu -Existing
Rc,·ctmenl
Existing limited public
IICCCSS conditions will
rem:iinalongthis
nmrowbeach.

Low to Moderate -
Will protect roadway
fromexistingcoustul
h112urds and possibly
some le\'e] of sea ]e\'cl
risc. lncrenscd \\'tlter
]e\'els will e\'entunllr
o,·crtop and penneaic
the re\'elmentnnd
inundate the rondwnv.

These imp11cts will be
more pronounced if not
combined \\ith
nourishment.

Bench \\idth loss if not
combined \\ith
frequent nourishment.
0-IOYears
SOM
S0.4M
No Re,·ctmcnl - Close
Southbound Seaward L11nc
(ScclionJ,1)
No impacts to public access
along the bench in short-tcnn
Access along the beach becomes
impacted in medium 10 long
tenn as se11 ]e,·cls rise.

Low -lncrcuscd wutcr levels
will nccclcrate erosion of the
bluff The lnndwnrd lune would
become \'Ulnerohle to
undermining and nooding in
short-tenn
Sell\\"llrd lune would require
deconstruction ifre,·etment is
remo,·ed.
0-10 Years
$0.2M
Not npplicnblc .. •
No Rn·clmcnt -Shin all
Trame to Norlhhound
Allwinwnl (Sl-cllon 3.2)
No impacts to access points
nssuming roadway connections
lo existing beach IICCCSS points
nonh and south of the project
orea ore included in the project.

Access olong t11e beach becomes
impacted in medium lo long
tenn as sea le\'clsrise.

High -The nonhbound
alignment has sufficient
ele\'lltion nnd setback distance to
withstand high sea IC\"el rise
projections.

Southbound \ones would require
deconstruction ifre,·etment is
rcmcl\'ed.
50+Years
SIM
Not applicable•••
Rahe Rcn•lmcnt (S«llon
J..t.1)
Moderate lo significant impacts
for access along the beach
assuming hard protection occurs
olone,crosion,,ill resultino
narrow beach.

Moderate -Will protect ro11dwoy
from increased runup due to sen
lcvc\risc. lncrcased \\'11\erle\'c\s
may e\'entun\ly o,·ertop and
pcnncatc the rc\'etmcnt and
inundate the roadway. These
impacts \1i\l be more
pronounced ifnol combined with
nourishment.

Bench \\idth loss if not
combined \\ilh frequent
nourishment.
25Years
S4M
S5M
• l'rd111111mry' ol'.l.:r11/111ag11/11u/,: ccn/, •1:c D1:,cnp/1011 1-..iu· m,d 1110/rt.\'fol' a11II111p11onJ a11d r11um11t1n t·o11mh·n-dfor 1l11J ntm1,1f;•, •• l11d11d1.•J i11ili/ll c-O{/ mu/ mal11tt•11m1c,·. l'awmclll l/{t:9v:k c·o~/1 ar.· ,wt 1·m1.~i(/.-,,•d. •••Future pm·nm:111 r,•11101•0/ t·ous tll't' 1101 c01uid.:r1.',l !1•ril 211/'l
Sc11wall (Section J.-1.2)
The cil\' would include new
beach access points and
viewpoints (like scowall and
street side impro\'cmcnts
between Pine Avenue W1d
Tamarack A,·enuc). If the \\ull is
constructed ,,ithout frequent
nourishment, bench erosion \\ill
result in narrow beach fronting
t11e w11!1. This would result in
moderate to significant impacts
olong and to the bench.

Modemlc -Will protect roadway
from sen le\'cl rise, ,1ill be more
cffecti,·e if combined with
nourishment.

Beach 11idth loss if not
combined \\ith frequent
nourishment.
25-50Yeors
SSM
S9M
Rcnw,·c Rc,·ctmenl & Imrlcmcnl Sort Prulccllon (Section J.5) Buch Nourhhmcnl
Beneficial impacts to public
access along II widened beach.

Modemtc -Beach nourishment
cnn keep pace \\ith modcrntc
le\'c\sofscn le\'el rise.

Frequency and volwne of
nourishment \\ill need to
incre11sc11sscn lcvels incrense.

Con result in intertidal and
nearshore habitat impacts.
5 Years; Repeated Application
Needed
S8M
$-WM
Winter Berm
Negligible beach access impacts
depending on lop width of benn
and bc11ch \\idlh. Beach grading
can focilitotc access 11long the
top ofbcnn or o,·er the bcnn and
m11y require regular frequency.

A sleep gradient will exist
SCU\\'llrd ofthc bcnn if the beach
is Mrrow or following II large
\\'IIYeCVCn\.

Ne11nhorcRccf
Bcncficinl impacts to public
access 11long n \\idcned beach.

Moderate -An nrtificinl reef and
Low to Moderate -Winier bench nourishment can keep
benns \\ill become less effccti\'e pace with moderate le\'els of sen os sea le\'els rise. le\'c\ rise. Moy require raising
the reef in the future.

Ncorshore rcefsorcosyet
Winter berm construction results unpro\'en desi(!JlS to stubilizc in temporary impacts lo bcochcs in southern California
intertidal beach habitats. because they ha\'e not been
ndeqlllltcly attempted.

I Y enr; Inst oiled Repeatedly 5-25 Yenrs
S0.125M Sl6M
SIM $20-35M
,,
(city of
Carlsbad
( JI If O I II I J

5. CONCLUSIONS
Final .·1/ternctlives Analysis Report: Las Encinas Revet111ent The 2015/2016 El Nifio winter produced a succession of large wave events that resulted in coastal erosion of the bluff and damage to the southbound Carlsbad Boulevard roadway near Las Encinas Creek in the City of Carlsbad. The damage and instability of the bluff prompted emergency response measures in the form of extension of an existing rock revetment to the north to stabilize the eroding bluff. This report was prepared in response to emergency permitting efforts that the city is pursuing with the CCC. The CCC has requested that viable alternatives to address the erosion and instability of this bluff be considered (Special Conditions 3 and 5 of emergency permit number G-6-15-0049). This repmi presents this alternatives analysis.

The city requests that the temporary rip rap protection be permitted with no change for a period of 5 years while the city develops a long-term management plan for the roadway. The long-term management plan would consider the options presented in this repmi and would be vetted through the city's public process prior to making a final decision. The city will continue to monitor the revetment as outlined in CDP No. 6-09-051-Al issued October 19, 2015.
(_ City of
Carlsbad
L d I If Or II I d

6. REFERENCES
Final .-1/tematives Analysis Report: las Encinas Revef111enf AECOM. 2012. Carlsbad Boulevard Realignment -Baseline Enviromnental Evaluation. Prepared by AECOM. Prepared for The City of Carlsbad. March 2012.

Cal trans. 2014. Pervious Pavement Design Guide. Office of Storm water Management. August 2014.

City of Carlsbad. 2002. Carlsbad Watershed Management Plan. February 2002.

Coastal Frontiers Corporation. 2016. 2015 Regional Beach Monitoring Program -Annual Report. Prepared for SANDAG. April 2016.

Coastal Frontiers Corporation. 2017. City of Carlsbad Fall 2016 Beach Profile Survey. Prepared for the City of Carlsbad. January 16, 2017.

GeoSoils, Inc. 2016. Geotechnical Evaluation of Coastal Bluff Stability-Carlsbad Boulevard, Las Encinas Creek Area, San Diego, California. Prepared by GeoSoils, Inc. Prepared for The City of Carlsbad Public Works. August 31, 2016.

Moffatt & Nichol. 2016. City of Carlsbad -Sea Level Rise Vulnerability Assessment-Draft. Prepared by Moffatt & Nichol. Prepared for the City of Carlsbad. June 2016.

April HJI 7
(City of
Carlsbad
L <1 I if o In I ,1
.,/;Jl'il 1() I .7
Final Alternatives Analvsis Report: Las Encinas Revet111e11/ APPENDIX A. EXHIBITS
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Beach Profile Origins
D Revetment 2016 (250-ft)
Revetment 2015 (270-ft)
Revetment 2009 (750-ft)
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1 inch = 400 feet
800
Feet
{_ City of
Carlsbad
(J1ifo1nl.1
April]() I 7
Final .·lltemalives Ana(vsis Report: Las Encinas Reve/111enl APPENDIX B. LAS ENCINAS REVETMENT AS-BUILTS
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EL NINO WINTER 2015-2016
CCC EMERGENCY PERMIT NO. G-6-15-0049
COASTAL DEVELOPMENT PERMIT (CDP)#6-09-051
WATER BOARD RGP#R9-2015-0214
WATER BOARD RGP#R9-2016-0108

CCC-CALIFORNIA COASTAL COMMISSION

RGP-REGIONAL GENERAL PERMIT
"AS BUILT"
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CARLSBAD BLVD EMERGENCY REVETUENT

APPENDIX B

LOCAL AGENCY REVIEW FORM
SECTION A (To BE COMPLETED BY APPLICANT}
Applicant City of Carlsbad
Project Description South Carlsbad Coastline Project in conformance with the Adaptation Management Plan and the coastal development permit conditions. Monitoring to continue every 5-years.

Location West of Carlsbad Blvd at Las Encinas Creek and between Solamar Drive and Island Way Assessor's Parcel Number N/A -public right-of-way along Carlsbad Blvd SECTION 8 (To BE COMPLETED BY LOCAL PLANNING OR BUILDING INSPECTION DEPARTMENT} Zoning Designation _O~p_e_n_S~pa_c_e _____________ _
General or Community Plan Designation
Local Discretionary Approvals
Open Space
~a d~ac ------
~a d~ac
rgJ Proposed development meets all zoning requirements and needs no local permits other than building permits.

D Proposed development needs local discretionary approvals noted below.

Needed Received
□ □
□ □
□ □
□ □
□ □
Design/Architectural review
Variance for
Rezone from
Tentative Subdivision/Parcel Map No.

Grading/Land Development Permit No.
□ □
□ □
Planned Residential/Commercial Development Approval
Site Plan Review
□ □
□ □
□ □
CEQA Status
D Categorically Exempt
Condominium Conversion Permit
Conditional, Special, or Major Use Permit No.

Other
Class
Item
Item
D Negative Declaration Granted (Date)
--------
-------------------
□ Environmental Impact Report Required, Final Report Certified (Date) [gl Other Statutorily exempt from CEQA pursuant to Guidelines Section 15269, emergency projects.

Prepared for the City/County of Carlsbad by Scott Donnell --------------------- Date 4/18/2024 Title Senior Planner
4 Attachment G
Supporting Information to CCC Staff Report
Staff recommend approval of Permit No. 6-16-0450-A2 granted to the City of Carlsbad for follow-up approval to retain a 270 linear foot rock revetment authorized by emergency permit for five years, and after-the-fact approval of construction of an additional 250 linear foot revetment on the beach protecting southbound lanes of Carlsbad Boulevard. The project site is located on the west side of southbound Carlsbad Boulevard, north of Encinas Creek, Carlsbad, San Diego County.

This amendment authorizes CDP #6-16-0450 (City of Carlsbad) for an additional seven years by amending Special Condition 1. In March 2018, the Coastal Commission approved the underlying CDP (Ref. No. 6-16-0450), which granted follow-up approval to retain a 270 linear foot rock revetment authorized by an emergency permit (G-6-15-0049/City of Carlsbad) as well as after-the-fact approval of an additional 250 linear foot revetment, for five years (i.e., March 14, 2023). In 2023, the Commission approved an amendment to the underlying CDP (Ref. No. 6-16-0450-Al), which extended authorization for an additional year (i.e., March 14, 2024). The revetment is located on the beach, seaward of southbound Carlsbad Boulevard, south of Palomar Airport Road and north of Encinas Creek. The city has submitted this amendment request prior to the expiration of the authorization period, and the subject amendment does not undermine the intent of Special Condition 1, which was to ensure that the city actively seeks a longer-term solution to erosion at the subject site. The deadline for authorization was intended to allow the city to develop a Hazards Management Plan, a portion of which was completed in February 2024 for the South Carlsbad Climate Adaptation project. The seven additional years will allow the city time to apply for new grant funding to move the project from feasibility and conceptual design to finalization of the roadway alignment and environmental restoration alternatives, as well as time to conduct a construction feasibility study, and complete the environmental documentation and permitting. No adverse impacts are anticipated, and thus the proposed project will not adversely impact coastal resources and can be found in conformance with Chapter 3 policies of the Coastal Act.

The Executive Director had proposed an immaterial permit amendment for the July 9, 2026, Coastal Commission meeting. The Surfrider Foundation wrote a letter of opposition to immaterial processing of CDP Amendment No. 6-16-0450-A2, and the Commission approved scheduling a hearing.

Staff worked closely with the City of Carlsbad staff to obtain additional information on questions that were raised during the July 9, 2026, meeting. The city's responses are provided on page 3.

The city requests that the existing revetment be permitted to remain until the long-term hazards management plan and alternatives analysis for the revetment are updated and the long-term solution for the roadway is constructed in the future.

1. Limited Authorization Period and Long-Term Hazard Management Plan. (a) This coastal development permit authorizes the shoreline protection for &B(-thirteen years from the date of this permit approval (i.e., to March 14, ~2031) or until the time when the currently existing structures warranting armoring are no longer present or no longer require armoring for such protection, whichever occurs first.
(b) No later than~thirteen years after the approval of this permit (i.e., by March 14, ~2031), the permittee or successor in interest shall apply for a regular coastal development permit to implement a long-term Hazards Management Plan for Carlsbad Boulevard that addresses current and future coastal hazards present at the site.The Hazards Management Plan shall incorporate measures to adapt to sea level rise over time and provide for the long-term protection and provision of public improvements, coastal access, public opportunities for coastal recreation, public views and coastal resources, including beach and shoreline habitat. These measures may include, but need not be limited to, phased implementation of beach nourishment, soft protection, managed retreat, and focused or small-scale armoring. The Plan shall also include a timeline or event-driven schedule for implementation The plan shall evaluate and consider all potential constraints, including geotechnical and engineering constraints; potential phasing options with timelines; project costs for the preferred project and alternatives; and potential funding options. The plan shall be submitted with documentation sufficient to support all analyses, methodologies and conclusions. (c) lfthe permittee proposes to retain any portion of the shoreline protection beyond thes-Hf thirteen year authorization period in the permit application required by subsection (b) of this Special Condition or in a separate amendment to this permit, the permittee is required to include in the permit application an evaluation of alternatives to the shoreline protection and related elements that are capable of protecting the development while eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site. The information concerning these alternatives must be sufficiently detailed to enable the Coastal Commission to evaluate the feasibility of each alternative for addressing site issues under the Coastal Act and the LCP. The permittee must also include mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial *thirteen year period of authorization.

CITY OF CARLSBAD RESPONSES TO COMMISSIONER QUESTIONS ON JULY 9, 2026

1. What is the City of Carlsbad's plan for winter 2026-2027 since it is an El Nino year? City response:

The City of Carlsbad continues to closely monitor conditions along the bluff to help protect public safety and maintain access on Carlsbad Boulevard. City staff conduct daily inspections of the area and completed crack-sealing work on July 28, 2026, to help reduce water infiltration into the pavement. The city is also working with a geotechnical engineer and land surveyor to evaluate current bluff conditions and identify any changes that may affect the roadway.

City staff continue to regularly monitor bluff conditions, tidal forecasts and weather patterns at the site on an ongoing basis .. Currently, monitoring is performed at least weekly, with more frequent monitoring planned during the rainy season or whenever severe weather is forecast.

Emergency Response Plan
Short-term plan
If the asphalt berm on southbound Carlsbad Boulevard moves more than three inches of either horizontal or vertical deflection from its current condition, the City Engineer will make a recommendation to the City Manager to consider declaring a local emergency to address the road failure.

The preferred emergency response would be to construct up to 500 feet of additional rock revetment extending from the north end of the existing boulders to the exposed bedrock to the north. This additional revetment would help stabilize the bluff and protect the roadway. The city anticipates that placement of additional rock revetment would require approval through an emergency coastal development permit.

Intermediate-term plan
If additional shoreline protection is not approved or bluff erosion continues to affect the roadway, the city will consider a longer-term interim traffic configuration to safely maintain travel through the area. This approach would shift all vehicle traffic to the current northbound roadway between Solamar Drive and Island Way, providing one travel lane in each direction with dedicated bike lanes. Pavement improvements, including centerline treatments, would be incorporated to improve safety and reduce the potential for crossover collisions.

This concept is similar to an alternative evaluated in the 2017 Final Alternative Analysis Report - Las Encinas Revetment. With this approach, the existing revetment would remain in place while the current southbound roadway, which is more vulnerable to wave action and bluff erosion, could continue to serve recreational uses as conditions allow.

2. What is the political will to keep the project moving forward? How has it been demonstrated? City response:

The City of Carlsbad's General Plan, adopted in 2015, includes several guiding principles for south Carlsbad Boulevard, which is a key transportation corridor along the coast. In 2020, the city accepted a grant from the State Coastal Conservancy for the South Carlsbad Climate Adaptation Project, focused on studying the feasibility of relocating the southbound lanes of Carlsbad Boulevard from approximately Manzano Way to Island Way to address sea level rise and bluff erosion. With this grant funding, the city completed conceptual design alternatives including a 30% preliminary engineering design for a realigned roadway, an adaptive management plan, a cliff erosion assessment report and a habitat restoration alternatives analysis.

The Carlsbad Boulevard Realignment Project, later renamed as the South Carlsbad Coastline Project, and the Carlsbad Realignment Project -Manzano Drive to Island Way, is included in the city's Capital Improvement Program (Project Nos. 6031, 19081, and 6113). The project involves conducting "a study of future roadway realignment alternatives, infrastructure needs, land uses, commercial land development options, public park and coastal access opportunities, and related long term coastal planning issues, constraints and processes." The City Council has appropriated $2 million of the city's general fund to continue refining a phased adaptation approach and additional preliminary engineering and permitting for the preferred realignment alternative. The preferred option is a two-lane road with roundabouts, which the City Council approved on June 20, 2023.

The realignment project is identified as a priority project in the City Council's 5-Year Strategic Plan 2023-2027, which was adopted on Oct. 11, 2022. The project continues to be a priority as shown in the progress report presented to the City Council on Feb. 24, 2026.

Additional funding is needed to complete final engineering and permitting and fully construct the roadway realignment. City staff have applied for several grants:
• Five grant applications were not approved
• One application is awaiting a decision from the Ocean Protection Council • One more application will be submitted to the State Coastal Conservancy soon.

3. What is the status of the project?
City response:

City staff are exploring grant options for engineering design, permitting and construction of the preferred long-term roadway alternative. Staff continue to monitor and survey the revetment and provide summary reports to the California Coastal Commission at 5-year intervals with the most recent report submitted in April 2025 and the next one to be submitted in April 2030.

The April 2025 monitoring report indicated "In general, we found that the 4-ton and 2-ton rock revetment has performed well over the years, with only a few rocks dislodged. However, this is not expected to jeopardize the integrity of the revetment, roadway, or bridge under normal weather conditions. It was evident from our site inspection that the beach elevation had dropped due to storm-induced erosion during the winter, but the beach may recover during the spring and summer seasons. This reversal was also encountered during previous inspections. We conclude that the revetment is in a stable condition and anticipate that it will provide protection for years to come."
City staff have been coordinating with California Coastal Commission staff to extend the existing permit to keep the revetment in place until a long-term alternative solution is selected and constructed.

The city gathered initial input from the community about its priorities, needs and values related to the future use of the entirety of South Carlsbad Boulevard, extending beyond the segment adjacent to the revetment. In early 2022, community members were invited to provide feedback with some expressing the desire to keep the area in its current configuration citing its natural beauty, while others preferring improvements such as safer biking and walking, maintaining or improving access to the beach, maintaining ocean views and protecting the environment, bluffs and habitat. Additional community input will be solicited as the city develops the long-term plan for this area.

4. What is the funding plan for the project, including grants that the city has applied for and any funding gap for construction, appropriation and funding projections? City response:

The city has appropriated $2 million of the city's general fund for a share of the design and permitting costs of the Carlsbad Boulevard Realignment -Manzano Drive to Island Way Project and has submitted for seven grants to date including:
o Not approved
• U.S. Department of Transportation FY24 Safe Streets and Roads for All Implementation Grants Application: applied for $15,975,832 for Terra mar Area, submitted May 2024 • California Transportation Commission (CTC) Active Transportation Program (ATP) Program Application: applied for $14.97 million, submitted June 2024 • U.S. Deartment of Transportation RAISE (now BUILD): applied for $5.4 million, submitted January 2025
• U.S. Department of Transportation PROTECT: applied for $6.75 million, submitted February 2025
• California Governor's Office of Emergency Services Hazard Mitigation Grant Program:
applied for $5.05 million, submitted July 2025
o Pending decision
Ocean Protection Council Senate Bill 1 Sea Level Rise Adaptation Implementation Grant:
applied for $2 million, Track 2 Letter of Intent (LOI) submitted February 2026. Invited to submit full application, submitted June 2026, decision expected September 2026 o Pending full application
State Coastal Conservancy Grant. Pre-application submitted summer 2025 for $5 million. Invited to submit full application, applications due on a rolling schedule (pending submittal) Considering the city has submitted seven grants and we have not yet been successful at securing grant funding, the target timeframe to pursue an economically feasible project includes the following milestones:
• Early 2027 -city staff plan to bring a report to the City Council on the status of funding with recommendations for analyzing additional alternatives with lower costs
• Spring 2027 -city staff plan to develop an updated alternatives analysis and long-term hazards management plan including documentation sufficient to support all analyses, methodologies and conclusions and an economic analysis of the options, and addressing measures to adapt to sea level rise over time and provide for the long-term protection and provision of public improvements, coastal access, public opportunities for coastal recreation, public views and coastal resources, including beach and shoreline habitat (measures may include, but need not be limited to, phased implementation of beach nourishment, soft protection, managed retreat, focused or small scale armoring) and a timeline or event-driven schedule for implementation of the plan
• Fall 2027 -City staff plan to present the updated alternatives analysis and long-term hazards management plan to the City Council for approval • Winter 2027-2028 -City staff plan to prepare final design and environmental studies on the preferred alternative and submit grant applications for the construction phase. Scoping of the environmental document and permitting begins.
• Summer 2030 -City staff plan to present environmental documents and local permits to the city's Planning Commission and the City Council for approval
• Winter 2030-2031-City staff plan to submit a coastal development permit application for the preferred alternative for south Carlsbad Boulevard to the California Coastal Commission
• Spring 2031-City staff plan to present to the City Council funding options for construction of long-term improvements

5. What has the city done with assistance and collaboration with the State of California regarding the construction funding timeline?
City response:

To support the efforts of both the Carlsbad Boulevard Realignment Project and the analysis of sea level rise impacts and adaptation, the city partnered with the Center for Climate Change Impacts and Adaptation in 2019 to apply for a Climate Ready grant from the State Coastal Conservancy. The funds assisted in the climate adaptation planning along the southern portion of the Carlsbad coastline, including a study of coastal erosion from the Terra mar neighborhood to the Batiquitos Lagoon and realignment of Carlsbad Boulevard south of Palomar Airport Road.

The State Coastal Conservancy is a non-regulatory state agency that supports projects to protect coastal resources and increase opportunities for the public to enjoy the coast. Specifically, the grant-funded project included modeling of a detailed sea level rise impact analysis, development of potential adaptation scenarios, facilitation of discussions with state agencies, design of a roadway realignment (Carlsbad Boulevard south of Palomar Airport Road) and preparation of a report. The report was presented to the City Council upon completion for policy direction and to start public engagement on the future of south Carlsbad Boulevard and its surroundings. The grant amount was $533,175, which includes funding to support work by the Center for Climate Change Impacts and Adaptation and a project consultant. The project period was from summer 2020 to spring 2023.

The city also collaborated with the Coastal Commission staff on the coastal development permits for the revetment while it continued its efforts to further the planning and funding for the long-term solution. The city will continue to collaborate with the Coastal Commission staff regarding the future developments of the plan through the completion of the project.

6. What are the city's plans regarding an emergency coastal development permit and furthering hard armoring?
City response:

As discussed in the city's response to Question #1 above, If the asphalt berm on southbound Carlsbad Boulevard moves more than three inches of either horizontal or vertical deflection from its current condition, the City Engineer will make a recommendation to the City Manager to consider declaring a local emergency to address the road failure. The preferred emergency response would be to construct up to 500 feet of additional rock revetment extending from the north end of the existing boulders to the exposed bedrock to the north. This additional revetment would help stabilize the bluff and protect the roadway. The city anticipates that placement of additional rock revetment would require approval of an emergency coastal development permit.

The city plans to finalize a long-term hazards management plan as presented above. As a part of this effort, the city plans to retain the hard armoring revetment in place until the completion of the long-term project to prevent further damage to road infrastructure.

7. The permittee must also include mitigation for the effects of any remaining portion of the shoreline protection on public access and recreation and other coastal resources during the expected life of the remaining shoreline protection beyond, but not including, the initial~ thirteen year period of authorization.

City response:

As part of an updated hazards management plan and alternatives analysis, mitigation for effects of long-term shoreline protection will be developed and will consider:
• Eliminating or reducing impacts to public access, public views, shoreline processes including sand supply, marine resources, and other coastal resources at the site • Continued monitoring and maintenance to ensure protection performs effectively

Carlsbad City CouncilAugust 14, 2026

Carlsbad City Council
August 14, 2026