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HomeMy WebLinkAbout2024-04-02; Beach Preservation Commission; ; Adaptive management plan for the South Carlsbad Boulevard Climate Adaptation Project Meeting Date: April 2, 2024 To: Beach Preservation Commission From: Kyle Lancaster, Parks & Recreation Director Staff Contact: Tom Frank, Transportation Director/City Engineer tom.frank@carlsbadca.gov, 442-339-2766 Katie Hentrich, Senior Program Manager katie.hentrich@carlsbadca.gov, 442-339-2623 Subject: Adaptive management plan for the South Carlsbad Boulevard Climate Adaptation Project Recommended Action Receive a report on how a 1-mile segment of south Carlsbad Boulevard could be managed to protect people, the environment and infrastructure from the effects of anticipated sea level rise. Executive Summary Traffic safety and environmental sustainability are top City Council priorities. A California State Coastal Conservancy1 grant provided the City of Carlsbad with an opportunity to advance both priorities by redesigning a section of Carlsbad Boulevard prone to flooding and vulnerable to future sea level rise. The grant was intended to demonstrate how coastal cities could move and adapt infrastructure based on the latest sea level rise modeling. The 1-mile segment of southbound Carlsbad Boulevard addressed by the grant, between Manzano Drive and Island Way, is located within the project area of a longer-term city project from Manzano Drive to the city’s southern border at La Costa Avenue. That larger project envisions moving the southbound lanes of Carlsbad Boulevard to the east and repurposing about 60 acres of coastal land for recreation, trails and other uses. 1 The Coastal Conservancy is a state agency established in 1976 to protect and improve natural lands and waterways, help people access and enjoy the outdoors, and sustain local economies along the length of California’s coast. April 2, 2024 Item #3 1 of 41 BEACH PRESERVATION COMMISSION Sta ·· Re ·o . . The grant project for the 1-mile segment included two main components: • Road plan: The first is a conceptual design showing how the road could be moved away from the immediate coastline, where modeling shows the sea level will rise in the next 96 years. • Adaptive management plan: The second is a management plan that would be used to inform how and when infrastructure should be moved eastward. On June 20, 2023, city staff presented three options for how the road could be reconfigured to move infrastructure away from the coast. The City Council voted to approve one of the options to proceed to the next stage of design, in compliance with the grant requirements. At that meeting, the City Council also directed staff to return to the Beach Preservation Commission and the City Council to discuss options for the management plan. One option is to “retreat now,” meaning make all the changes all at once. The other is to use a phased approach where changes would be made incrementally over the next 96 years, as needed. Staff will present this information to the City Council on April 23, 2024. The grant project was completed on Feb. 28, 2024. At this time, the city does not have an active project or funding to continue where the grant project left off. Because of this, it is not necessary to choose an adaptation approach now. If the City Council were to direct staff to proceed with the next steps of this project, staff would need to analyze additional information about the potential costs and benefits of the two approaches to help the City Council make an informed decision. Explanation & Analysis Project area flooding South Carlsbad Boulevard has a history of erosion and instability near Las Encinas Creek. The city has had to close this section of the roadway, including at the Las Encinas Bridge, during April 2, 2024 Item #3 2 of 41 -South Carlsbad Coastline Project / South Carlsbad Boulevard Climate Adaptation Project Carlsbad Blvd coastal storms, rending this part of the coastline inaccessible. This poses a safety concern because emergency vehicles have to take a longer route to get to nearby homes and businesses and is an inconvenience to those traveling south along the coast. In response to flooding, the city extended rock barricades twice under an emergency permit approved by the California Coastal Commission. Most recently in 2016, the city placed rock shoreline protection during periods of high surf that led to partial closure of the roadway and emergency repair work. The California Coastal Commission issued a coastal development permit on Dec. 29, 2015, which was extended in March 2024. As a condition of the emergency permit, the Coastal Commission required the city to pursue a more permanent solution. The California Coastal Conservancy grant project provided the first step toward developing that solution. Staff submitted an amendment request to the California Coastal Commission on March 14, 2024, for a five-year extension to pursue additional grants and studies to complete the design, permitting and construction of a lasting solution. If the extension is not approved and the rock barrier is removed prior to the realignment of the infrastructure, this segment of Carlsbad Boulevard would likely experience heavy erosions and would need to be closed once critically damaged. Existing Policies and Plans The city has been studying and planning for future sea level rise for many years. Specifically, the South Carlsbad Boulevard Climate Adaptation Project builds on data and guidance in three documents previously approved by the City Council: 1. Sea Level Rise Vulnerability Assessment This report completed in 2017 identifies areas in Carlsbad on the coast and around lagoons that are most susceptible to damage from an increase in the sea level. • The report projects potential hazards over two timeframes – through 2050 and 2100. It analyzes the relative risks and rates how vulnerable different areas are. • The report also describes possible “adaptation strategies,” which are ways to help address future coastal flooding and erosion. • The project area is identified in the report as an area that may be extremely vulnerable to coastal flooding. 2. General Plan Safety Element In January 2024, the City Council approved an update to the General Plan’s Safety Element, which identifies community safety risks and establishes goals and policies to protect the public from those risks. The Safety Element sets forth several goals related to safety along the coast: • Give priority to non-structural shoreline protection options and limit or prohibit hard shoreline protective devices (Goal 6-P.15) • Require removal or relocation of structures away from sea level rise hazards if public health and safety risks exist, if essential services can no longer be maintained, if the structures are no longer on private property due to migration of the public trust April 2, 2024 Item #3 3 of 41 boundary, or if the development requires new or augmented shoreline protective devices that would not otherwise be permitted (Goal 6-P.16) 3.Declaration of a Climate Emergency In September 2021, the City Council declared a climate emergency, which is part of a worldwide effort to raise awareness of the impacts of climate change and instill a greater sense of urgency to address it. The declaration affirms the city’s current sustainability efforts and ongoing commitment to protecting the environment stating, “any meaningful action that stands a chance of success at mitigating and adapting to the effects of climate change requires mobilization without delay.” What the Grant Project Included City staff completed the following work products as part of the grant project: •A conceptual design of the realigned roadway (Exhibit 1) •An adaptive management plan that includes a decision framework for when to move segments of south Carlsbad Boulevard based on the anticipated coastal hazards caused by sea level rise (Exhibit 2) •A cliff erosion assessment •A habitat restoration analysis of the Las Encinas Creek area The cliff erosion assessment and the habitat restoration analysis helped inform the road design and management plan. Conceptual design City staff developed conceptual designs, which included rough layouts and traffic analysis information to show how southbound Carlsbad Boulevard from Manzano Drive to Island Way could be moved to the east. The designs were developed to meet the following goals: •Move and protect infrastructure from hazards caused by sea level rise •Provide a safe and efficient roadway for all modes of travel •Promote walking, biking and other forms of active transportation •Slow down traffic along the coastline for safety On June 20, 2023, city staff presented three road options to the City Council for consideration. •The City Council selected a two-vehicle lane road with roundabouts. •This design complies with the California Complete Streets Act and local policies that were previously approved by the City Council, including the General Plan’s Mobility Element, Sustainable Mobility Plan and Climate Action Plan. Management plan In addition to a road design that moves infrastructure away from the coast, the grant funded the development of a plan for how and when these changes could be made. A future step will include a policy decision regarding two options presented in the adaptive management plan: April 2, 2024 Item #3 4 of 41 Retreat now • The “retreat now” option would move infrastructure away from the coast all at once, rather than incrementally, which could enhance the width of the beach at the Las Encinas Creek outfall segment. Phased adaptation • The phased adaptation option would move the southbound Carlsbad Boulevard vehicle lane to the east and repurpose the old road for walking and biking paths to be used as long as it is safe to do so. • The walking and biking paths would be moved to the east as needed based on flooding, erosion and other signs of sea level rise over the next 96 years. Project Segments The management plan splits the project area into four segments. For each segment, the plan includes: • Types of physical events, or “triggers,” such as cliff erosion or flooding and the frequency that would signal the time to move infrastructure landward • Lead times needed for these actions • Observational data to collect to track the proposed “triggers” • Frequency of data collection Each segment has unique characteristics that would determine when infrastructure would need to be relocated. Palomar Airport Road The main vulnerability of concern in this segment is cliff erosion. The phased adaption plan would 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. The conditions described below would trigger the need to proceed with moving infrastructure to the east. April 2, 2024 Item #3 5 of 41 Climate adaptation segments 2070 Cliff Hazard Zone 2120 Cliff Hazard Zone Palomar Airport Road Solamar Drive Las Encinas Creek Island Way Trigger Action Lead time Pedestrian walkway 15’ from cliff edge Begin planning and implementation of corridor shared by bikes and pedestrians (similar to area like the Coastal Rail Trail) 3-5 years Bikeway 15’ from cliff edge Begin planning and implementation of relocating the trail inland or demolish corridor and redirect bikes and pedestrians to the sidewalk and bike lane next to vehicle lane 3-7 years Relocated bikeway 15’ from cliff edge Begin planning and implementation of demolishing corridor and redirect bikes and pedestrians to the sidewalk and bike lane next to vehicle lane 3-5 years Solamar Drive The main vulnerability of concern in the Solamar Drive Segment is also cliff erosion. The phased adaptation plan would focus on utilizing the roundabout as long as feasible with options to explore increased access and stabilization (i.e. erosion control) alternatives as well as changing the roundabout to a signal to regain some space. Trigger Action Lead time Class 1 path 15’ from cliff edge Begin planning and implementation transitioning the roundabout to a single lane with traffic signal 5-10 years Las Encinas Creek In the Las Encinas Creek segment, flooding at the “dip in the road” at the mouth of Las Encinas Creek is the primary concern. Flooding in this portion of the segment is already affecting the roadway during coastal storms. The image below shows what this area would look like under retreat now, once all the changes had been made, including totally removing the southbound road, as well as the rock barriers (called a “revetment”) along the beach. • The changes would also include habitat restoration and a new bridge over Las Encinas Creek to accommodate north and southbound traffic, including walking and biking paths. • The changes would create conditions that support the formation of an approximately 700-foot pocket beach with sand, as well as a sand dune and dune wetlands. • The Las Encinas Creek estuary and beach would be allowed to evolve naturally and without major maintenance after the project is constructed. April 2, 2024 Item #3 6 of 41 A phased approach to this segment would be based on the following conditions: Trigger Action Lead time Rock revetment needs significant repair that exceeds $5 million Begin planning and implementation of demolishing corridor and redirecting pedestrians and bikes to sidewalk and bike lane next to vehicle lane 5-10 years The corridor is flooded 10 times in one year Begin planning and implementation of demolishing corridor and redirecting pedestrians and bikes to sidewalk and bike lane next to vehicle lane 5-10 years Section 4.3.3.2 of the report includes a preliminary comparison of the phased adaptation and retreat now (make all the changes at once) options. Further analysis is needed prior to staff recommending an approach on “retreat now” or “phased adaptation” options. This analysis would include a geotechnical report, biological survey, topographical analysis, refined conceptual designs, cost estimates based on the additional studies, and an options analysis including costs and benefits. April 2, 2024 Item #3 7 of 41 Legend r'"'7 H.ibitat Enhancement L-.;jArea(HEA) , .. " ''"$ "'i>Proje;tion.L...t:,.,ICcrlOM1MCoriic HomootlllOII.., NomAl'llrir;a'\11183 Ori:!.NA01r.83Stalof'lancClllfomiaVlnPSo«l6Fcol Island Way Trigger Action Lead time No trigger identified since relocated infrastructure outside of the coastal hazard zone N/A N/A A Caveat Carlsbad’s adaptive management plan is one of only a few plans created for coastal cities in the State of California. As such, best practices for creating such a management plan may evolve, providing additional guidance in the future. Community Engagement Because the grant project was technical in nature and the end product would be conceptual only, the city engaged property owners, businesses and residents in the immediate study area in a discussion about road design options. City staff focused the adaptive management plan engagement efforts on public agencies including the California Coastal Commission, California State Parks and Encina Wastewater Authority. Comments included: • Adding in a buffer for the cliff erosion trigger • Using more objective metrics to monitor flooding and overtopping • Making triggers clearer and more accountable • Updating the adaptive pathways visuals to make them easier to understand • Considering future financial needs related to adaptation Staff incorporated these edits into the adaptive management plan included in Exhibit 2. Staff recommend broader public engagement to coincide with future phases of this project, if it were to move forward. Next Steps The grant focused on a conceptual design. Completing the preliminary design and permitting for this project by 2028 is a key task in the City Council’s 5-Year Strategic Plan. To meet this deadline and move this design forward to implementation, the following steps would be needed: • Identification and securing of funding source(s) • Procurement of design, environmental studies and options analysis including costs and benefits • Public engagement to identify ideas, preferences and concerns related to how land could be repurposed • Design of beach access points and other recreational areas • Further technical studies and options analysis to support final design • Engineering design beyond 30% through final design • Environmental analysis, documentation and review • Permitting April 2, 2024 Item #3 8 of 41 • Bidding • Construction Another consideration when determining next steps is the status of the larger south Carlsbad Boulevard project. The City Council may wish to consider changes to the 1-mile segment addressed in the grant project in context with the entire south Carlsbad Boulevard corridor. That project is currently included in the city’s Capital Improvement Program and initial community engagement has been completed. At this time, the City Council has not directed staff to proceed with the next steps, which would include preliminary design and engineering of the 3-mile corridor, along with additional community engagement. Environmental Evaluation The California Environmental Quality Act, or CEQA, and its implementing regulations, the CEQA Guidelines, adopted by the Secretary of the California Natural Resources Agency, list classes of projects that have been determined not to have a significant effect on the environment and as a result are exempt from further environmental review under CEQA. The City Planner has determined that this report is statutorily exempt from the requirements of CEQA pursuant to CEQA Guidelines sections 15262 (feasibility and planning studies) and 15378(b)(5), which exempts organizational or administrative activities of governments that will not result in direct or indirect physical changes in the environment. This organizational and administrative activity relates to results of a study to prepare an adaptation plan for a portion of a roadway segment in the city (South Carlsbad Boulevard Climate Adaptation Project). This general direction provided by the City Council does not have a legally binding effect on any possible future discretionary action. Public input received and technical information prepared during the planning process will be utilized in preparing a future environmental review document to support the South Carlsbad Boulevard Climate Adaptation Project. Exhibits 1. Conceptual design of the two-lane road with roundabouts 2. Adaptive management plan April 2, 2024 Item #3 9 of 41 2'8'8'8'3'10.5'4'10.5'3'8'6'2' TYPICAL ROADWAY CROSS SECTION N.T.S LID BIKE BUFF VEHICLE MED.VEHICLE BUFF BIKE LID SIDEWALK 2%2% R/W 73' R/W VAR 8'8'10.5'3'4'10.5'3'8'5'12' CLASS I PATH MEDIAN/ BARRIER BIKE BUFF VEHICLE MED. VEHICLE BUFF BIKE SIDEWALK 2%2% 2'10' SIDEWALK R/W 2' 86'R/W VAR VAR 8' 1.5% 10' PED 4' TYPICAL 20' WIDE CLASS 1 36' 2'VAR R/W 8'2' 1.5% 2' TYPICAL TRAIL CROSS SECTION N.T.S 95' 2%2% 2'8'8'8'3'10.5'4'10.5'3'8'6'2' LID BIKE BUFF VEHICLE MED.VEHICLE BUFF BIKE LID SIDEWALK R/WR/W VAR12' CLASS I PATH 10' SIDEWALK TYPICAL BRIDGE CROSS SECTION N.T.S ### CARLSBAD BLVD RDWY RESILENCY PLAN ALTERNATIVE 2 ROUNDABOUT ALTERNATIVE 11215903 FIG 1 PLAN NORTH 0 400'200' 9370 Sky Park Court Suite 140 San Diego, CA 92123 USA T 1 858 244 0440 W www.ghd.com Plot Date:Cad File No:30 January 2024 - 3:52 PM \\ghdnet\ghd\US\San Diego\Projects\561\11215903\Digital_Design\ACAD 2018\Figures\2022-06-28_Carlsbad Plan Exhibit_Roundabout Alternative-rev.dwgPlotted by:Abdulhakim Ali Note: 1. GHD conceptual design developed from City of Carlsbad provided topography. Roadway design components will need to be modified in future phases of the project to coincide with final surveyed topographic and parcel line information. Legend: Proposed Class I Trail Proposed Roadway Coastal Hazard Zone Proposed Bridge Property Line Landscape Areas Proposed Pedestrian Pathway North County Transit District RR So l a m a r D r Palo m a r A i r p o r t R d Is l a n d W a y Carlsbad Blvd Oceanview Dr Retain Existing Parking "Complete Street" roadway with sidewalks and bike lanes Las Encinas Creek Restoration Area 500' Span Bridge Class 1 shared path for pedestrians, slower moving mobility options Pedestrian Pathway Coastal Hazard ZoneRetain Existing Parking Retain and expand Existing Parking Avenida Encinas Exhibit 1 April 2, 2024 Item #3 10 of 41 • • I • • • •• " • • • I .. • • j, > • r4 \ -• ,. • • • 'I' • • • • T 7 t D 9 ~ 9 % / ,w <CC --ta;,~ lliiiiiill PPJ-_JEC-[c//._[\c\GE~ D !-TE .. • . ._ .... ' I I I I ' " I I I I I II I I I I I I I . ,... • r Jo ~ L ' -~ ~ ~ ~~ ~~ ~ -~ • t ~ ~ -~ ~ -Jo ~ ' I I I I I ' I I I I • ' ' ' l :S-;/ __ ..----_-_\' '·. ./ ·---_,, > .J z 0 ~ w - > w ~ ~ 0 LL 2'8'8'8'3'10.5'4'10.5'3'8'6'2' TYPICAL ROADWAY CROSS SECTION N.T.S LID BIKE BUFF VEHICLE MED.VEHICLE BUFF BIKE LID SIDEWALK 2%2% R/W 73' R/W VAR 8'8'10.5'3'4'10.5'3'8'5'12' CLASS I PATH MEDIAN/ BARRIER BIKE BUFF VEHICLE MED. VEHICLE BUFF BIKE SIDEWALK 2%2% 2'10' SIDEWALK R/W 2' 86'R/W VAR VAR 8' 1.5% 10' PED 4' TYPICAL 20' WIDE CLASS 1 36' 2'VAR R/W 8'2' 1.5% 2' TYPICAL TRAIL CROSS SECTION N.T.S 95' 2%2% 2'8'8'8'3'10.5'4'10.5'3'8'6'2' LID BIKE BUFF VEHICLE MED.VEHICLE BUFF BIKE LID SIDEWALK R/WR/W VAR12' CLASS I PATH 10' SIDEWALK TYPICAL BRIDGE CROSS SECTION N.T.S ### CARLSBAD BLVD RDWY RESILENCY PLAN ALTERNATIVE 2 ROUNDABOUT ALTERNATIVE 11215903 FIG 1 PLAN NORTH 0 400'200' 9370 Sky Park Court Suite 140 San Diego, CA 92123 USA T 1 858 244 0440 W www.ghd.com Plot Date:Cad File No:30 January 2024 - 3:52 PM \\ghdnet\ghd\US\San Diego\Projects\561\11215903\Digital_Design\ACAD 2018\Figures\2022-06-28_Carlsbad Plan Exhibit_Roundabout Alternative-rev.dwgPlotted by:Abdulhakim Ali Note: 1. GHD conceptual design developed from City of Carlsbad provided topography. Roadway design components will need to be modified in future phases of the project to coincide with final surveyed topographic and parcel line information. Legend: Proposed Class I Trail Proposed Roadway Coastal Hazard Zone Proposed Bridge Property Line Landscape Areas Proposed Pedestrian Pathway North County Transit District RR So l a m a r D r Palo m a r A i r p o r t R d Is l a n d W a y Carlsbad Blvd Oceanview Dr Retain Existing Parking "Complete Street" roadway with sidewalks and bike lanes Las Encinas Creek Restoration Area 500' Span Bridge Class 1 shared path for pedestrians, slower moving mobility options Pedestrian Pathway Coastal Hazard ZoneRetain Existing Parking Retain and expand Existing Parking Avenida Encinas Exhibit 1 April 2, 2024 Item #3 11 of 41 • • I • • • •• " • • • I .. • • j, > • r4 \ -• ,. • • • 'I' • • • • T 7 t D 9 ~ 9 % / ,w <CC --ta;,~ lliiiiiill PPJ-_JEC-[c//._[\c\GE~ D !-TE .. • . ._ .... ' I I I I ' " I I I I I II I I I I I I I . ,... • r Jo ~ L ' -~ ~ ~ ~~ ~~ ~ -~ • t ~ ~ -~ ~ -Jo ~ ' I I I I I ' I I I I • ' ' ' l :S-;/ __ ..----_-_\' '·. ./ ·---_,, > .J z 0 ~ w - > w ~ ~ 0 LL South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan you South Carlsbad Climate Adaptation Project Long-Term Master Plan / Adaptive Management Plan City of Carlsbad 28 February 2024 Exhibit 2 April 2, 2024 Item #3 12 of 41 0 -- GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project i South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Exhibit 2 April 2, 2024 Item #3 13 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project ii 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 Exhibit 2 April 2, 2024 Item #3 14 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project iii 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 10 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 5 Photo 2. Coastal Flooding within the Project Area 7 Exhibit 2 April 2, 2024 Item #3 15 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 1 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. Exhibit 2 April 2, 2024 Item #3 16 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 2 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 1. South Carlsbad Boulevard Climate Adaptation Project Area Exhibit 2 April 2, 2024 Item #3 17 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 3 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. Figure 2. Preferred Project Figure 3. Typical Roadway (above) and Bridge (below) Cross Sections Exhibit 2 April 2, 2024 Item #3 18 of 41 RN/ 2' 6' LID RN/ VAA 2' 10' I SIDEWALK J J 7 I ArH wh,:re Clan I and sldll!walkfl'ICJ'ffwhen itdapUtlontr1UiP:t(s)occur 8' 3' BIKE BUFF ' 12' CLASS I PATH 2% 73' 10.5' 4' 10.5' VEHICLE MED. VEHICLE ~ t 2% TYPICAL ROADWAY CROSS SECTION N.T.S 86' 5' 8' 3' 10.5' MEDIAN/ BIKE BUFF VEHICLE BARRIER -JJ ~ 2% TYPICAL BRIDGE CROSS SECTION N.T.S Mlaputlonttlwrisloctur 3' 8' BUFF BIKE ' RN/ 4' 10.5' 3' 8' 8' ,2' VAR MED. VEHICLE BUFF BIKE SIDEWALK I t JJ C I-2% C ,--J GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 4 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 4. Typical Mobility Corridor Section Exhibit 2 April 2, 2024 Item #3 19 of 41 2' 10' PED 1.5% - 36' TYPICAL 20' WIDE CLASS 1 4' 2' 8' 1.5% - TYPICAL TRAIL CROSS SECTION N.T.S 8' R 1W 2' VAR GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 5 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. Exhibit 2 April 2, 2024 Item #3 20 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 6 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 5. Modeled Average Cliff Retreat Distance in Tabular Format (left) and Graphical Format (right) (Derived from: SIO 2022) Figure 6. Cliff Hazards in the Project Area with Sea Level Rise Projections for 2070 and 2120 3.2 Coastal Flooding 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). Exhibit 2 April 2, 2024 Item #3 21 of 41 Time Horizon 2050 2070 2100 2120* Distance from Cliff Edge Baseline (ft) Average 22.6 40.5 77.5 108.1 ·s10 modeling does not project past 2100, interpolation was used to derive the 2120 value ~ " u C -~ 0 ~ I!' & a. ~ '!: u 200 ~ Max Retreat 175 -t-Ql ~Avg Retreat 150 125 100 75 so 25 0 2010 -t-Q3 ~ Min Retreat 2030 S10 Modeled Cliff Retreat 7.1' SLR 8.B'SLR 2050 2070 2090 2110 2130 Time Horizon NorthCountyTraMitOi<lrict!UI GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 7 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Photo 2. Coastal Flooding within the Project Area (source: City of Carlsbad) 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) Exhibit 2 April 2, 2024 Item #3 22 of 41 Y••• 2050 Flood H=NI Zone J Vear 2100 Flood Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 8 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. Figure 8. Adaptive Management Plan Project Segments Exhibit 2 April 2, 2024 Item #3 23 of 41 Palomar Airport Road Segment 2070 Cliff Hazard Zone ' Island Way Segment GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 9 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. 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. Exhibit 2 April 2, 2024 Item #3 24 of 41 Toe of Cliff l Top of Cliff Edge Setback l Buffer 1 Asset GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 10 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 10. Increments of 10-ft Setbacks Across the SLR Projections of Cliff Top Retreat 4.2.2 Coastal Flooding 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 Niño 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 $5M (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/ Exhibit 2 April 2, 2024 Item #3 25 of 41 200 180 160 140 ~ ~ ~ 120 ci "' ~ 100 a, a: C. 0 f-;; 80 u 60 40 20 0 2020 10 ft Setback Increments Overlaid on S10 Modeled Cliff Retreat ---><----Max Retreat ----Ql ......-Avg Retreat ----Q3 ~ Min Retreat 2.0' SLR ----------------- 0.9' SLR 2030 2040 2050 2060 7.1' SLR 3.6' SLR o."' / ----------------------~-- - - - - - - -- - - - - - - - -.":""'"< -- - - - - - - 2070 2080 Time Horizon 2090 Min Retrru 2100 2110 8.8' SLR 10 ft Setback Increments 2120 2130 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 11 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. 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. Exhibit 2 April 2, 2024 Item #3 26 of 41 Phase 0 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 I I OR Phase 2 Relocated Class 1 .... I Phase 3 I Demolish Corridor & Redirect 1 Active Recreation to New Roadway • Action 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 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 12 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 12. Phase 0 (as-built condition) of Palomar Airport Road Segment 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 Exhibit 2 April 2, 2024 Item #3 27 of 41 Palomar Airport Road Segment - Phase O (As-Built Condition) PED 36' TYPICAL 20'WIDECLASS t 4' l ~ ~ • ' ... 2070 Cliff Hazard Zone 11112120 Cliff Hazard Zone 'Phase 1 (Mobility Corridor reduced to shared use Class 1 Corridor) 20 TYPICAL 2~ WIDE CLASS 1 RN/ 8' 8' l VAA 2070 Cliff Hazard Zone illl 2120 Cliff Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 13 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). Figure 14. Palomar Airport Road Segment – Adaptive Phase 2 Figure 15. Palomar Airport Road Segment – Adaptive Phase 3 Exhibit 2 April 2, 2024 Item #3 28 of 41 Phase 2 (Move Class 1 Corridor Landward Incrementally) 2070 Cliff Hazard Zone 11112120 Cliff Hazard Zone 'Phase 3 (Demolish Mobility Corridor & Redirect Active Recreation to New Roadway) 2070 Cliff Hazard Zone -2120 Cliff Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 14 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. 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). Exhibit 2 April 2, 2024 Item #3 29 of 41 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 5-1 O yrs*) *Assumes PEIR and available funding Distance include 5' buffer between setback and asset GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 15 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 17. Phase 0 (as-built condition) of Solamar Drive Segment Phase 0 (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. Exhibit 2 April 2, 2024 Item #3 30 of 41 Solamar Drive-Phase 0 2070 Cliff Hazard Zone 11112120 Cliff Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 16 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan 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.californiacoastline.org Exhibit 2 April 2, 2024 Item #3 31 of 41 'Solamar Drive-Option 1 ,(Bidirectional Roadway with Signal) -~~i.:1@11~-:::-~~_,_ __ --~ ---___,,,._,_ :21 • I aza ,--·---!'---./ E 069) ) Cliff Edge .. S. Carlsbad State Beach -- GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 17 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 0 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. Exhibit 2 April 2, 2024 Item #3 32 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 18 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 20. Phase 0 in the Las Encinas Segment overlaid with flood (top) and cliff erosion (bottom) hazards. Figure 21. Phase 0 (as-built conditions) for the Phased Retreat Alternative Exhibit 2 April 2, 2024 Item #3 33 of 41 Oceanview Or Right of Way Limit with adjacent Class I and Sidewalk 2070 Cliff Hazard Zone 2120 Cliff Hazard Zone Oceanview Dr Legend • C§:3 ~!~tf~~;~ancement Year 2050 Flood Hazard Zone Las Encinas Creek Restoration Area " , .. ,~ ~ t.llpf>rojectoon:LambertConlormalConic HorironlllD11hm:NorthArneric:1111983 Grid:NAD1983ShitePleneCalilomia'IIAPS0406Feet SOO'Span Bridge "Complete Street" roadway with sidewalks and bike lanes Class 1 shared path for pedestfi slower moving mobility options Year 2100 Flood Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 19 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 22. Phase 0 (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. Exhibit 2 April 2, 2024 Item #3 34 of 41 Legend , .. '~;,-~ "'°Prcjeclion:lllmMConformalConic HDrilonlalDallm:NorthAmencan\983 Grid:NAD1983Staiel'lar.oClllilomillVIFlPS0406fecl GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 20 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan Figure 23. Adaptive Pathways for Las Encinas Creek Segment Exhibit 2 April 2, 2024 Item #3 35 of 41 Phased Adaptation I -------Vipt n r --------, I I : Demolish & Redirect Active : :Transportation to New Bridge : -----------r------------ OR ___________ J ___________ _ • Option 2 : I Demolish & Build Retreat Now : __ !-J_e~ ~!~~s_ ~ !3_0!1!~':'.Y~~k ___ _ w/ or wo/ Class 1 Boardwalk Triggers * * 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 overtopping of rock revetment and flooding of Mobility Corridor 10 times in one year (i.e., 12 month period). Action Begin planning & implementation of Option 1 or 2 (lead time assumption 5-10 yrs*) *Assumes PEIR and available funding GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 21 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 Phased Adaptation Retreat Now Permitting and Construction: Can all elements of the design be implemented at once? 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. Yes. This option would perform all actions at one time, not requiring any additional permitting or construction. Financial: What are the differences in costs between the two options (qualitatively)? 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 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. 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. Coastal Hazards & Public Safety: Would the option provide public protection from existing and projected future coastal hazards? 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. 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). Sandy Beach: Will the alternative sustain a dry, sandy beach in the study area? 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. 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. Access: What are the differences in public access and use between the two options? 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. 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. Habitat Restoration: How would these options benefit the restoration of Las Encinas Creek? 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. 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. Exhibit 2 April 2, 2024 Item #3 36 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 22 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. Figure 24. Phase 0 (as-built condition) of the Island Way Segment Exhibit 2 April 2, 2024 Item #3 37 of 41 Island Way-Phase 0 (Roundabout) 3: 2070 Cliff Hazard Zone 2120 Cliff Hazard Zone GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 23 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 Metric Monitoring Method Frequency Cliff Erosion High-tech / Data driven Topographic surveys (traditional survey profiles, orthophotogrammetry, LiDAR) Semi-annual Surveys Extreme Events Low-tech/ Interpretive Site amenities (e.g., colored pavers, benchmarks, signs) indicating bluff top edge erosion and encroachment into established thresholds Continuous Beach Erosion Beach profile surveys (back beach to depth of closure) Subaerial beach surveys via orthophotogrammetry or LiDAR Semi-annual Surveys Extreme Events Rock revetment / Armoring Integrity Topographic Survey (traditional survey profiles, orthophotogrammetry, LiDAR) Structural condition inspection Annual Post Extreme Events Roadway Maintenance Costs Financial tracking of cleanup and repair activities Annual Flood Frequency Flood elevation thresholds (e.g., minor, moderate, significant) are determined and tracked by combined tide and wave observations outputs in coordination with SIO; Supplemented by site observations and closure tracking. Continuous Extreme Events Annual Public Access / Usability Site Observations Closure Tracking Aggregated Big Data Sources As Needed 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. Exhibit 2 April 2, 2024 Item #3 38 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 24 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 10 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. Exhibit 2 April 2, 2024 Item #3 39 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 25 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. Exhibit 2 April 2, 2024 Item #3 40 of 41 GHD | City of Carlsbad | South Carlsbad Climate Adaptation Project 26 South Carlsbad Blvd Climate Adaptation Project -Adaptive Management Plan ghd.com The Power of Commitment Exhibit 2 April 2, 2024 Item #3 41 of 41 m WWW ➔ Adaptive Management Plan for the South Carlsbad Boulevard Climate Adaptation Project Tom Frank, Transportation Director/City Engineer April 2, 2024 { City of Carlsbad RECOMMENDED ACTION Receive a report on how a 1-mile segment of south Carlsbad Boulevard could be managed to protect people, the environment and infrastructure from the effects of anticipated sea level rise. ITEM 3 : SOUTH CARLSBAD BOULEVARD 22 { City of Carlsbad TODAY’S PRESENTATION •Overview of grant study •Adaptive management plan 3 ITEM 3 : SOUTH CARLSBAD BOULEVARD { City of Carlsbad PROJECT AREA 4 ITEM 3 : SOUTH CARLSBAD BOULEVARD -South Carlsbad Coastline Project / South Carlsbad Boulevard Climate Adaptation Project Carlsbad Blvd •Sea Level Rise Vulnerability Assessment •General Plan Safety Element •Climate Emergency Declaration •Coastal Development Permit •California Complete Streets Act •General Plan Mobility Element •Sustainable Mobility Plan •Engineering Standards •Climate Action Plan CITY OF CARLSBAD POLICIES AND PLANS 5 { City of Carlsbad COASTAL DEVELOPMENT PERMIT •Requires a long-term Hazard Management Plan •Measures may include phased implementation, soft protection, managed retreat, focused or small-armoring •Include potential phasing with timelines 6 ITEM 3 : SOUTH CARLSBAD BOULEVARD { City of Carlsbad SCOPE OF WORK •Conceptual design of realigned roadway •Adaptive management plan •Cliff erosion assessment •Habitat restoration analysis of Las Encinas Creek area •Funding ended Feb. 28, 2024 7 ITEM 3 : SOUTH CARLSBAD BOULEVARD { City of Carlsbad CONCEPTUAL DESIGN 8 •Move and protect infrastructure from hazards caused by sea level rise •Provide a safe and efficient roadway for all modes of travel •Promote walking, biking and other forms of active transportation •Slow down traffic along the coastline for safety ITEM 3 : SOUTH CARLSBAD BOULEVARD { City of Carlsbad 9 •Retreat now – move infrastructure away from coast all at one time •Phased adaptation – move car traffic to east, repurpose southbound lane for walking and biking paths and move as needed ITEM 3 : SOUTH CARLSBAD BOULEVARD ADAPTIVE MANAGEMENT PLAN { City of Carlsbad 10 CLIMATE ADAPTATION SEGMENTS ITEM 3 : SOUTH CARLSBAD BOULEVARD 2120 Cliff Hazard Zone Palomar Airport Road Solamar Drive Las Encinas Creek Island Way {city of Carlsbad 11 PALOMAR AIRPORT ROAD ITEM 3 : SOUTH CARLSBAD BOULEVARD Trigger Action Lead time Pedestrian walkway 15’ from cliff edge Shared corridor for walking and biking (similar to area like the Coastal Rail Trail) 3-5 years Bikeway 15’ from cliff edge Relocate trail inland or demolish corridor and redirect bikes and pedestrians to the sidewalk and bike lane next to vehicle lane 3-7 years Relocated bikeway 15’ from cliff edge Demolish corridor and redirect bikes and pedestrians to the sidewalk and bike lane next to vehicle lane 3-5 years { City of Carlsbad 12 SOLAMAR DRIVE ITEM 3 : SOUTH CARLSBAD BOULEVARD Trigger Action Lead time Walking and biking path 15’ from cliff edge Transition roundabout to single lane with traffic signal 5-10 years { City of Carlsbad 13 LAS ENCINAS CREEK ITEM 3 : SOUTH CARLSBAD BOULEVARD Trigger Action Lead time Rock revetment needs significant repair that exceeds $5 million Demolish corridor and redirect pedestrians and bikes to sidewalk and bike lane next to vehicle lane 5-10 years Corridor is flooded 10 times in one year Demolish corridor and redirect pedestrians and bikes to sidewalk and bike lane next to vehicle lane 5-10 years { City of Carlsbad 14 r=7 Habitat Enhancement L__;j Area(HEA) Tidal Wetland Establishment Area 60 120 180 Feet DEMO EXISTING SB ROAD PRISM & CONSTRUCT DUNE SYSTEM 15 ISLAND WAY ITEM 3 : SOUTH CARLSBAD BOULEVARD Trigger Action Lead time No trigger identified since relocated infrastructure outside of the coastal hazard zone N/A N/A { City of Carlsbad 16 ITEM 3 : SOUTH CARLSBAD BOULEVARD COMMUNITY ENGAGEMENT •Adaptive management plan outreach focused on public agencies •California Coastal Commission •California State Parks •Encinas Wastewater Authority •Comments incorporated into plan { City of Carlsbad 17 •One of few plans created in State of California •Further analysis needed before recommending an approach ITEM 3 : SOUTH CARLSBAD BOULEVARD ADAPTIVE MANAGEMENT PLAN { City of Carlsbad 18 •Grant does not fund environmental analysis or construction •Consider larger south Carlsbad Blvd project •Based on City Council direction: •Further technical studies, options analysis •Public engagement •Engineering ITEM 3 : SOUTH CARLSBAD BOULEVARD NEXT STEPS { City of Carlsbad RECOMMENDED ACTION 192 ITEM 3 : SOUTH CARLSBAD BOULEVARD Receive a report on how a 1-mile segment of south Carlsbad Boulevard could be managed to protect people, the environment and infrastructure from the effects of anticipated sea level rise. { City of Carlsbad SUPPLEMENTAL SLIDES 20 21 (b) No, later than five yea.rs after the approval of this permit (i.e. b,y March 14 20,23) the permittee o,r successor in interest shall apply for a regular co,a.sta.l develo·pment permit to, implement . _ z for Carlsb·a.d Bo,uleva.rd that addresses current and future coastal hazards present at the site. The Hazards Management Plan shall inco14Po,ra:te measures to, adapt to, sea level rise o,ver time and pro,vide fo,r the lo,ng term protection and pro,visio,n o,f public impro,vements coastal access public o,ppo,rtunities for co,astal recreation public vie,vs and co,astal resources including b,each and shoreline habitat (measures may include but need not be limited to phased implementa.tio·n of b·ea.ch no,urish.ment so,ft protectio,n managed retreat fo·cused o,r small-scale armoring) and ime line o,r event driven schedule fo,r implementatio,n of the plan. The plan shall e, aluate and co·nsider all potential co,nstra.ints including geotechnical and engineering co,nstraints • IILd--..... ~-------~~s~1n~g~o~p~i~o~n~s~w~1~~t~1m~e!!1~~~~d..!i~~.lA:'::1:--tJ:jte ~~--~~o .. t=e::::c~t a~ _ . The plan shall be sub·mitted v.rith do,cumenta.tio,n sufficient to, suppo,rt all analyses metho,dolo,gies and co·nclusio,ns. 22 DESCR IPTIION ,Q,F PR,OPOSED AMENDMENT : Request an amendment for five years to comp lete stud ies 1, design 1, perm itting and identify a fund ing source for a pro ject in conforms with the cond itions of the perm it. Further ana lys is is needed include a geotechn ica l report. biolog ica l survey , topograph ica l ana lys is,, refined conceptua l des igns 1, cost estimates based on the add itiona l stud ies 1, and an options ana lys is includ ing costs and lbene.fits . Th is add itiona l ana lys is is cr itica l in formu lat ing a recommended approach and fina l pro ject scope of work . The city wou ld continue to provide revetment mon itor ing every 5-years 1, with the next survey ing requ ired by May 111, 2025. PROJECT AREA ITEM 3 : SOUTH CARLSBAD BOULEVARD 23 Ila nut 10iNi'l!!nih.ip* -flL'1ril • ruiad -~cft.liifr .. --~---------■-pi-..-...-... {_ City of 1Carlsbad Focus on moving roadway to adapt to climate change Not focused on public access Not focused on parking area designs Not focused on recreation opportunities BACKGROUND FOR CONCEPTUAL DESIGN 24 (city of Carlsbad TWO LANES WITH ROUNDABOUTS 25 \, /""""'-"" Legend: .-------, Proposed Class I Trail L____J -Proposed Pedestrian Pathway -Proposed Roadway C=::J Proposed Bridge C=::J Coastal Hazard Zone C=::J Landscape Areas Property Line C!>i15tal Access Coastal Haz.a rd Zone Ric ht of Way Limit with adjacent ctass I and Sidewalk Q<>eam,lewor \ coaslal Access North C-00nty Transit District RR \. ,Right of way Limit wilh adjacent Class I and Sidewalk / 500'5pan Bridge I ,r ,_ , "complete Street" road-y with sidewalb and bike lanes \ \_ cfass 1 shared ,path far pedestrians, \ $lower movi111: mobirity o.ptions ', Pedestrian Path,way ' Retain Existing Parking TWO LANES WITH ROUNDABOUTS 26 Retain Existing Parking Coasta I Access \ Coastal Hazard Zone Right of Way Limit with adjacent Class I and Sidewalk • ~ Retain Existing Parking Coastal Access 27 TWO LANES WITH ROUNDABOUTS Avenida Encinas North County Transit District RR Right of Way Limit with adjacent Class I and Sidewalk Restoration Area \ Class 1 shared path for pedestrians, slower moving mobility options Pedestrian Pathway Retain Existing Parking CROSS-SECTIONS 28 2' 36' TYPICAL 20' WI DE CLASS 1 10' 4' 2' 8' PED 1.5% TYPICAL TRAIL CROSS SECTION N.T.S 8' R/W 2' VAR R/w 2' 6' LID 8' 3'' I Bl E Uf • 2% 73' 10.5' 4 ' 10.5' VE HICLE MED. VEHIO.E J t 2% TYPICAL ROADWAY CROSS SECTI ON N.T.S 3' 8' 8' 8' 2' VAR R/W UF BIKE UD SIDEWALK • CROSS-SECTIONS 29 R/W VAR 2' 10' 12' I SIDEWALK OASS IPATH J !•J I ~ 7 Ri ,w 2 10' 12' 6' 8' 3,' I SIDEWALK CLASS I PA 11H LID BIKE BUFf S' f.,IEDIAN' aARRIEF - 86' &' 3' 10 .S' 4' BIKE BUFF VEHICLE MED. • J 2% ~ TYP ICAL :BRIDGE CROSS SECTION N.T.S 95' 10.5' 4' 10.5' 3' VEl11CLE MEO., VEHICLE BUH t R/W 10.5' 3' &' 8' 12.' VAR VEH ICLE BUFF BIKE SIDEWALK I t • C 2% C t ,8' 8 8' .2. w VAR Rf BIKE LID SIDEWALK •Qualitative input •Open-ended questions •20,000+ individual comments 30 THREE MILE COASTLINE (city of Carlsbad WHAT WE HEARD •Keep the area natural, retain what makes it special •Prioritize safe, accessible biking and walking paths •Preserve views •Keep the needs of residents top of mind •Maintain or improve access to the beach •Keep traffic moving •Protect the environment, bluffs from erosion •Ensure any shops do not interfere with natural, undeveloped feel 31 COMMUNITY PRIORITIES •Safer bike lanes, including some separated from the flow of car traffic •Safe, wide walking paths •Less noise and air pollution from traffic when enjoying the coast •Slowing down traffic along the coast •Making it safer to cross the road to get to the coast •Maintaining ocean views for drivers and residents who live along Carlsbad Boulevard 32 (city of Carlsbad 36 A • -., eri:,, or ca~~o-,.. -\. -.. · ~ l ·g I : .·.. > .,;~ I "' ~. L 1 ~ . ~ I ~ ~, C 1:· \ ~,. ~· fl ' ~/ .. -.. ... ·~~.i~• 37 38 Measure distance Click on the map to add to your path Total distance: 1,290.29 ft (393 .28 m)