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HomeMy WebLinkAbout2020-02-24; Parks & Recreation Commission; ; 0220-1 ADA BEACH ACCESS FEASIBILITY STUDY AND TRAIL CONNECTIVITY TO TAMARACK STATE BEACH FEASIBILITY STUDYMeeting Date: Feb. 24, 2020 To: Parks & Recreation Commission From: Kyle Lancaster, Parks & Recreation Director Staff Contact: Tim Selke, Parks Services Manager Subject: American with Disabilities Act Beach Access Feasibility Study and Trail Connectivity to Tamarack State Beach Feasibility Study Recommended Action Receive an informational report on the Americans with Disabilities Act (ADA) Beach Access Feasibility Study and the Trail Connectivity to Tamarack State Beach Feasibility Study. Executive Summary On July 24, 2018, the City Council adopted a resolution authorizing the execution of a Professional Services Agreement for the preparation of feasibility studies for the ADA Beach Access Project, Capital Improvement Program (CIP) Project No. 6065, and the Trail Connectivity to Tamarack State Beach Project, CIP Project No. 4063. The feasibility studies evaluate alternatives to construct ADA accessible pedestrian walkways and ramps to provide a connection from Carlsbad Boulevard to the beach, as well as the potential for a trail connection from the North Shore Agua Hedionda Lagoon Trail to Tamarack State Beach. The ADA Beach Access Feasibility Study evaluated five alternatives using criteria established by the project team. The project team goals were to develop up to two preferred alternatives for ADA beach access. The two preferred alternatives selected for this purpose are located north of Pine Avenue, and adjacent to Tamarack Avenue. The Trail Connectivity to Tamarack State Beach Feasibility Study evaluated the feasibility of constructing a tunnel or undercrossing to connect the North Shore Agua Hedionda Lagoon to Tamarack State Beach. The study evaluated five alternatives to determine engineering feasibility that took into consideration factors such as terrain, sea level rise, and constructability. The cut-cover tunnel was found to be the most feasible option to connect the North Shore Agua Hedionda Lagoon Trail to Tamarack State Beach. Discussion This report provides an overview of the ADA Beach Access Feasibility Study and the Trail Connectivity to Tamarack State Beach Feasibility Study, including a review of the existing conditions, study approach, alternatives analysis and results. ADA Beach Access Feasibility Study The primary objective of the ADA Beach Access Feasibility Study was to evaluate the feasibility of constructing one or more ADA compliant pedestrian walkways and access ramps from Carlsbad Boulevard to the beach areas, between the parking lot just north of Pine Avenue to 5 of 143 the cold-water inlet bridge just south of Tamarack Avenue. At the north end of the project (near Pine Avenue), the roadway is approximately 30 feet above the beach and at the south end, the roadway is about 12 feet above the parking lot at Tamarack Beach. Pedestrian access to the beach is currently provided via six stairways and two ramps. Vehicular access is provided as an extension of Pine Avenue to Frazee State Beach and of Tamarack Avenue to Tamarack State Beach. The slopes of the two ramps at Pine Avenue and at Tamarack Avenue exceed the allowable ADA slopes, at 15.6% and 9.9%, respectively, without landings. Taking into account the existing access utilization, community input, vegetation constraints analysis, and the engineering evaluation, all described in the feasibility study, the following five different alternative ramp locations were identified for further evaluation: 1.North of Pine Avenue 2.Pine Avenue 3.Cherry Street 4.Tamarack Avenue Restroom 5.South of Tamarack Avenue Access Road The evaluation criteria used to select the preferred ramp locations from the five alternative locations was based on the following 10 criterions as developed by the project team: 1.Usage / Demand 2.Safety and Convenience 3.Construction Feasibility / Complexity 4.California Coastal Commission Acceptance 5.Aesthetics 6.Public Input 7.State Parks Concurrence 8.Vulnerability 9.Biological Resources 10.Geotechnical / Geology A detailed evaluation was then conducted of the five alternative locations and the two preferred alternative locations were determined to be at the location North of Pine Avenue and at the Tamarack Avenue Restroom. The results of this evaluation are summarized by location as follows: 1.North of Pine Avenue (Preferred Alternative #1): This alternative location scored highest across all criteria except for criteria #8, vulnerability. This location may be vulnerable to sea level rise and storm damage because the end of the walkway ramp is at grade and not sheltered by shoreline protection. However, some of the existing rip-rap at the end of the ramp could be relocated to address this deficiency. In addition, the community 6 of 143 and project stakeholders indicated that their most ideal location for ADA access would be near Pine Avenue due to the proximity to Carlsbad Village compared to other locations further to the south. 2. Pine Avenue: This location scored lower than the North of Pine Avenue location due to the complexity of constructing the ramp in the narrow area between the existing restroom and the upper sea wall walkway. It would also result in greater impacts to biological resources and require landform alterations at the end of the ramp. 3. Cherry Street: This location resulted in the lowest score because it scored poorly on the criterion of usage/demand, safety/convenience, and public input. 4. Tamarack Avenue Restroom (Preferred Alternative #2): This alternative location scored second highest overall. The project stakeholders also indicated that this location would be preferred if more than one ramp could be constructed – i.e., in addition to the Pine Avenue location. 5. South of Tamarack Avenue Access Road: This alternative scored lower than the Tamarack Avenue Restroom location due to sea level rise and storm damage vulnerability because the walkway would not land behind the lower seawall. This location also scored low in regard to safety/convenience as the walkway would cross the vehicle drive aisle to access the beach and would not allow for ADA access to the existing restroom. The project team developed conceptual design plans and photo simulations for the two preferred alternative locations which are displayed in Figures 4-7 of the study. The Pine Avenue ramp project would involve constructing an ADA compliant ramp that begins at the parking lot north of the intersection of Pine Avenue and Carlsbad Boulevard. The 389-foot ramp would change direction once, extending the pathway southward within the bluffs. The ramp would be designed with an incline for 7.8 percent. The ramp would be elevated as it descends the bluff, ranging at distances of approximately two to nine feet above the existing bluff below. The proposed ramp at the Tamarack Avenue Restroom would begin at the top of the bluff near the existing showers and restroom and would extend southward, parallel to the existing access road to the Tamarack State Beach parking lot. The existing road/sidewalk south of the proposed ramp would remain in its’ current state. Additionally, the existing staircase located perpendicular to the new ramp would be reconstructed. A portion of the ramp would be elevated along the bluff (approximately 60 percent of the ramp) ranging between two and five feet above the existing bluff. The ramp would be 196 feet in length and have an incline of 7.5 percent. The existing ramp down to the restrooms would also be rebuilt to be ADA compliant. The proposed design of the Tamarack Avenue ramp utilizes existing access points and disturbed areas in order to minimize impacts to the previously undisturbed bluff. 7 of 143 Trail Connectivity to Tamarack State Beach Feasibility Study The Trail Connectivity to Tamarack State Beach Project is located at the Cold-Water Inlet Bridge on Carlsbad Boulevard, south of Tamarack Avenue. The study’s main objective was to evaluate the feasibility of constructing a pedestrian tunnel or undercrossing to connect the North Shore Agua Hedionda Lagoon Trail to Tamarack State Beach. The goal of this study was to develop a preferred alternative for the connection between the North Shore Agua Hedionda Lagoon Trail and Tamarack State Beach. Five alternatives were considered to provide a trail connection close to the Cold-Water Inlet. The project team determined that the crossing could either be underneath the existing bridge or under the existing road, north of the bridge. An overcrossing alternative was not considered due to the significant visual impacts that an elevated bridge structure would present. The following alternatives were considered for a trail connection at the north side of the existing bridge: 1. Pedestrian Bridge: This alternative would be located beneath the existing Carlsbad Boulevard bridge and would be supported on a pile foundation in front of the northern abutment. This option was considered infeasible because it would provide a maximum vertical clearance of 12.18 feet and would not meet the minimum required vertical clearance threshold of 12.5 feet. 2. Open Walkway: This alternative would be located on a retaining wall beneath the Carlsbad Boulevard bridge. This option was determined to be infeasible due to potential hydraulics impacts, it require deep foundations and would have to be closed during storm events. 3. Walled Walkway: This alternative is similar to the open walkway, but it includes walls to prevent water from entering the walkway. This alternative was determined to be not preferable due to the higher hydraulic impacts than the open walkway, the extensive foundations required for the wall and it would have to be closed during storm events. 4. Tunnel: This alternative would construct a standard tunnel underneath Carlsbad Boulevard. A tunnel typically requires a cover that is twice its diameter. In order to provide a nine-foot overhead clearance, which is the minimum clearance requested by the city for a closed crossing, the tunnel will need to be approximately 30 feet below ground and would be located beneath the required water surface elevation and would be prone to continual flooding due to the proximity of the lagoon. 5. Cut and Cover (Preferred Alternative): This alternative would be like the tunnel and would also be underneath Carlsbad Boulevard, however, the trench excavation is much shallower as the earth cover can be a minimum of 12 inches. The project team found this alternative to be the most feasible option for crossing at this location considering design limitations of the other alternatives. 8 of 143 As described above, the cut-cover tunnel was found to be the most feasible option to connect the North Shore Agua Hedionda Lagoon Trail and Tamarack State Beach. This alternative would consist of a single cell precast reinforced concrete box culvert crossing under Carlsbad Boulevard, north of the existing Carlsbad Boulevard Bridge. The proposed structure would be built using accelerated bridge construction (ABC) methods to minimize potential disruptions to traffic and adjacent residents. The completed tunnel structure would be 92.5 feet long and 12 feet wide and nine feet high, following the same skew of the existing Carlsbad Boulevard Bridge. On the west end of the culvert, at Tamarack State Beach, a four-foot berm is proposed to keep water out of the tunnel. Additionally, a gate can be added to both ends of the culvert so that the tunnel can be closed if flooded. To provide complete ADA access from the eastern side of Carlsbad Boulevard to Tamarack State Beach on the west, an ADA ramp connecting the eastern sidewalk of Carlsbad Boulevard to the North Shore Agua Hedionda Lagoon Trail would be provided. On the western side of the crossing under Carlsbad Boulevard, an ADA compliant concrete walkway would connect to the existing parking lot at Tamarack State Beach. The parking lot will be reconfigured to provide a four-foot wide ADA path of travel along the western edge of the existing parking lot. The parking lot will be restriped to accommodate the proposed ADA path of travel, while maintaining the existing number of parking stalls and minimum parking lot drive aisle widths. Fiscal Impact The feasibility studies developed planning level opinion of probable construction costs for the ADA access ramps and the Trail connectivity to Tamarack State Beach. The estimated cost for each of the ADA access ramps, including design and CEQA clearance, was $2,800,00 for each ramp. A detailed breakdown of the costs can be found in Appendix F of the Carlsbad ADA Beach Access Feasibility Study. The estimated costs for the Trail connectivity to Tamarack State Beach, including design and CEQA clearance, was $3,000,000. A detailed breakdown of the costs can be found in Appendix B of the Trail Connectivity to Tamarack State Beach Feasibility Study. Next Steps Staff presented like informational reports regarding the feasibility studies to the Traffic and Mobility Commission and the Beach Preservation Commission on Feb. 3 and Feb. 4, 2020, respectively. Staff is also scheduled to present a like informational report to the City Council on March 17, 2020. Staff will next prepare a request for proposals for a firm or firms to address the environmental review, agency permitting, engineering and construction documentation phases of these two projects. Exhibits 1.Final ADA Beach Access Feasibility Study 2. Final Trail Connectivity to Tamarack State Beach Feasibility Study 3. Conceptual Plans for ADA Beach Access and Trail Connectivity Feasibility Studies 9 of 143 Prepared for: Transportation Planning & Mobility Public Works Department City of Carlsbad 1635 Faraday Avenue Carlsbad, CA 92008-7314 Prepared by: 3900 5th Avenue, Suite 310 San Diego, CA 92103 January 2020 ADA Beach Access Feasibility Study Final Report 10 of 143 Table of Contents 1.0 Introduction ............................................................................................................... 2 Overview .......................................................................................................................... 2 Project Identification and Goals ...................................................................................... 2 Project Study Area ........................................................................................................... 2 2.0 Existing Conditions ..................................................................................................... 4 3.0 Feasibility Study Approach ......................................................................................... 4 Existing Access Utilization ................................................................................................ 4 Community Input ............................................................................................................. 5 Vegetation Constraints Analysis ...................................................................................... 6 Engineering Evaluation .................................................................................................... 9 Development and Evaluation of Ramp Alternatives ..................................................... 10 Evaluation criteria to select preferred ramp ................................................................. 10 4.0 Feasibility Study Results ........................................................................................... 11 Preferred Alternatives ................................................................................................... 11 Conceptual Design ......................................................................................................... 12 Opinion of Probable Construction Costs ....................................................................... 19 CEQA Clearance ............................................................................................................. 19 Appendices Appendix A Pedestrian Acitivity Analysis Appendix B Vegetation Constraints Memorandum Appendix C Existing Conditions Slope Analysis Appendix D Pine Avenue and Tamarack Avenue Ramp Options Appendix E Pine Avenue and Tamarack Avenue Ramps Appendix F OPCC and Structures Estimate Appendix G Environmental Constraints Table List of Figures Figure 1 Project Study Area .............................................................................................................. 3 Figure 2 Habitat Value Assessment .................................................................................................. 8 Figure 3 Pine Avenue Beach Access ................................................................................................ 13 Figure 4 Pine Avenue Ramp ............................................................................................................ 14 Figure 5 Tamarak Avenue Beach Access ......................................................................................... 15 Figure 6 Tamarak Avenue Restroom Ramp .................................................................................... 16 Figure 7 Design Character ............................................................................................................... 17 Figure 8 Plant Materials .................................................................................................................. 18 List of Tables Table 3.1 24-Hr Pedestrian Activity – Saturday, August 11, 2018…………………………………………………..5 Table 4.1 The Criteria for Evaluating Alternatives With Associated Weighting…………………………….11 11 of 143 1.0 Introduction Overview The City of Carlsbad Public Works – Transportation Department commissioned a feasibility study to evaluate alternatives to provide access to Carlsbad State Beach (beach) that are compliant with the Americans with Disabilities Act (ADA) requirements. Purpose The purpose of the project is to provide access for all pedestrians, regardless of ability, to one of the area’s premiere beaches. The importance of this project cannot be understated since it will allow the community to enjoy a beautiful natural-resource that is unique to the region. The proposed project promotes the spirit and vision of both the California Coastal Act and the Americans with Disabilities Act. Project Identification and Goals ADA Beach Access Study, CIP No. 60651 The project’s main objective is to evaluate the feasibility of constructing one or more ADA access ramps to provide a connection from Carlsbad Boulevard to the beach. A number of alternatives were considered and evaluated using criteria established by the project team. The project goal was to develop up to two preferred alternatives for this connection between Carlsbad Boulevard and the beach. Project Study Area The ADA Beach Access Study project area is along Carlsbad Boulevard and the beach from to the parking lot just north of Pine Avenue to the Cold-Water Inlet Bridge (bridge), just south of Tamarack Avenue. Figure 1 displays the project’s study area. 12 of 143 Figure 1 – Project Study Area 13 of 143 2.0 Existing Conditions Carlsbad State Beach, also known as Tamarack State Beach, stretches from the warm water jetties, just south of Tamarack Avenue, to Frazee Beach, near Carlsbad Village Drive. Carlsbad Boulevard runs along the bluffs above the beach along this stretch of coastline. At the north end of the project (near Pine Avenue), the roadway is approximately 30 feet above the beach; at the south end (bridge), the roadway is about 12 feet above the parking lot. Along these 4,200 lineal feet, pedestrian access is provided via six stairways and two ramps. Vehicular access is provided as an extension of Tamarack Avenue to Tamarack State Beach. The slopes of the two ramps at Pine Avenue and Tamarack Avenue exceed the allowable slopes defined by ADA at 15.6% and 9.9%, respectively and with no landings. The Carlsbad Seawall, a paved walking path along the coast, extends from Pine Avenue to Tamarack Avenue. The lower seawall runs along the bottom of the bluffs at the back beach and provides shoreline protection for the walking path and the bluffs. Stairs are provided to connect to lower seawall to the beach. The upper seawall includes a paved walking trail along the west side of Carlsbad Boulevard. The section of the coastline is highly utilized by people walking, jogging, and cycling. 3.0 Feasibility Study Approach This chapter describes the various studies performed as part of the selection process for the location of the proposed ramps. Existing Access Utilization In order to determine utilization at the existing points of access to the beach, pedestrian counts were conducted at eight (8) locations (see below) along Carlsbad Boulevard on an average Saturday (Saturday, August 11, 2018). 1. Pine Avenue Beach Access Ramp; 2. Sycamore Avenue Stairway; 3. Maple Avenue Stairway; 4. Cherry Avenue Stairway; 5. Hemlock Avenue Stairway; 6. Tamarack Avenue Stairway; 7. Tamarack Beach Parking Lot Access Road Walkway; and 8. Cold-Water Inlet Stairway. 14 of 143 Table 3.1 displays the pedestrian counts collected Saturday, August 11, 2018. TABLE 3.1 – 24-HR PEDESTRIAN ACTIVITY – SATURDAY, AUGUST 11, 2018 Location Total Pedestrian Counts Peak Hour Peak Hour Volume 1 – Pine Avenue Beach Access Ramp 5,720 7:00 PM 536 2 – Sycamore Avenue Stairway 1,599 2:00 PM 191 3 – Maple Avenue Stairway 1,249 1:00 PM 126 4 – Cherry Avenue Stairway 2,042 7:00 PM 206 5 – Hemlock Avenue Stairway 1,686 4:00 PM 173 6 – Tamarack Avenue Stairway 3,477 7:00 PM 316 7 – Tamarack Beach Parking Lot Access Road Walkway 1,758* 7:00 PM 215* 8 – Cold-Water Inlet Stairway 1,007 9:00 AM 120 Source: Chen Ryan Associates, June 2019. Notes: *Pedestrian volumes obtained using ratios developed based on counts from Friday, August 10th. As shown in Table 3.1, the Pine Avenue Beach Access Ramp was identified as the location with the highest pedestrian activity with 5,720 pedestrians on an average summer Saturday. It should also be noted that the combined number of pedestrians at the two available access points at Tamarack Avenue was 5,235. The Cold-Water Inlet Stairway was identified as the location with the lowest pedestrian activity with 1,007 pedestrians on an average summer Saturday. See Appendix A for pedestrian count worksheets. Community Input The project team conducted community and stakeholder outreach initiatives to identify the level of support and obtain community input for the ADA Beach Access Feasibility Study. These efforts included: • Stakeholder Meeting (November 15, 2018); • On-site “pop-up” events (November 16 and 17, 2018). The people who were invited to the Stakeholder Meeting were residents that had previously expressed a desire for better access to Carlsbad State Beach. Many of these stakeholders are wheelchair users and lived in the Carlsbad Village. They expressed that the village is a great for them due to the generally flat topography. The overwhelming consensus from this group was that their most ideal location for ADA access would be near Pine Avenue. Tamarack Avenue was identified as a potential 15 of 143 location if more than one ramp could be built. The reason for this overwhelming consensus is due to the close proximity to Carlsbad Village of a Pine Avenue ADA Ramp compared to other locations further to the south. The two “pop-up” events were held on-site. One was held on a Friday afternoon near Pine Avenue and the second was held on a Saturday morning near Tamarack Avenue. There was board support from the community for the project at these two events. “Pop-up” event held near Pine Avenue on November 16, 2018 Vegetation Constraints Analysis To aid in siting considerations that may minimize impacts to native habitats, the project team conducted a qualitative assessment of bluff habitats supporting native plants along the coastal bluffs in the project vicinity. This assessment included a field inspection of the site to determine species composition and relative cover values for native plants, non-native plants, and unvegetated areas. Bluff habitats were divided into areas (polygons) of similar cover proportions and depicted on a map. Common native species observed in the study area included coast prickly pear (Opuntia littoralis), California fuchsia (Epilobium canum), seacliff buckwheat (Eriogonum parvifolium), California boxthorn (Lycium californicum), coastal goldenbush (Isocoma menziesii), coast cholla (Cylindropuntia prolifera), and California encelia (Encelia californica). Common non-native species observed included, ngaio (Myoporum laetum), sea lavender (Limonium perezii), and natal plum (Carissa macrocarpa). On the basis of the relative cover values, each of the 12 mapped polygons were then ranked from highest potential impact to native plant resources (Rank of 1) to lowest potential impact to native plant resources (Rank of 12) on the basis of the assigned cover value using the following assumptions: ➢ Higher relative cover value of native plant implies higher potential impacts ➢ Higher relative cover value of non-native plants implies lower potential impacts ➢ Higher relative cover value of unvegetated implies lower potential impacts See Appendix B for the Vegetation Constraints Memorandum. 16 of 143 The vegetation assessment provides a ranking for potential habitat impacts associated with construction of ADA access along Carlsbad Boulevard. Figure 2 displays polygons and their respective ranking with the highest rankings reflect the lowest degree of impact to native and/or dense vegetation along the bluffs, while those with lower rankings represent those areas that should be avoided if feasible. For example, Polygon “I” had the lowest ranking and would result in the highest amount of impacts to native and/or dense vegetation, therefore this area was to be avoided. Polygon H has the highest ranking of 12 and would result in the least amount of impacts. Impacts to this resource represent one consideration among many, and helped inform siting efforts for the preferred alternatives. 17 of 143 Figure 2 – Habitat Value Assessment 18 of 143 Engineering Evaluation A number of steps were taken to evaluate the engineering feasibility of ADA access ramp(s) from Carlsbad Boulevard to the beach. Two key factors that were considered throughout this evaluation were landform alteration and shoreline protection. This is due to the project team’s understanding of the California Coastal Commission’s (CCC) desire to minimize landform alteration and installation of new shoreline protection along the coastline. A review of existing conditions was completed, including an evaluation of how long ADA compliant ramps would need to be at various locations within the study area. Existing utilities were also identified within the project area. These included the storm drain outfall at Pine Avenue and above ground irrigation within along the bluffs. In order to determine if the ramps could be constructed at grade while minimizing landform alteration, a slope analysis was completed along the bluffs within the study area. See Appendix C for slope analysis exhibits. Land Form Alteration Land form alteration is identified in the California Coastal Act as a significant environmental concern for the following reasons: • Land form alteration often leads to loss of habitat, erosion, runoff and water quality degradation. • Once land form alteration has occurred, it is difficult, if not impossible for an engineered area to replicate all the functions of an unaltered area. • Land form alteration in steep slope areas can have far more impact than in low relief areas. • Development in steep areas often proposes vast amounts of land form alteration to make the area safe and buildable. Slope Analysis Results The slope analysis showed slopes of stepper than 2:1 within the bluffs throughout the study area. These steep slopes led the project team to determine that an elevated ramp system with pile supports would be seen as more favorable compared to an at-grade ramp by both the CCC and CA State Parks. Geotechnical Based on preliminary review of existing conditions and the Geotechnical Investigation Report for the Tamarack Coastal Improvements Project prepared by AECOM on March 2018, since the proposed pile supports are entirely in the bluffs, putting it in formational soil (Terrace Deposits), liquefaction would not be an issue. 19 of 143 Development and Evaluation of Ramp Alternatives Based on the existing access utilization, community input, the vegetation constraints analysis, and the engineering evaluation, all described above, five (5) different alternative ramp locations were identified for further evaluation: • North of Pine Avenue • Pine Avenue • Cherry Street • Tamarack Avenue Restroom • South of Tamarack Avenue Access Road Evaluation criteria to select preferred ramp The project team identified fourteen (14) potential criterion for evaluation of the five alternatives. These included the following: 1. Usage / Demand 2. Safety and Convenience 3. Construction Feasibility / Complexity 4. California Coastal Commission Acceptance 5. Aesthetics 6. Public Input 7. State Parks Concurrence 8. Sea Level Rise / Storm Damage Vulnerability 9. Biological Resources 10. Geotechnical / Geology 11. Transportation / Traffic 12. Noise 13. Greenhouse Gas Emissions 14. Air Quality The project team participated in an online survey to rank the fourteen (14) potential criterion based on each team member’s opinion of what should be considered as most important. These ranking led to the elimination of the four (4) lowest scoring criterion, leaving the team with ten (10) criterion for ranking the alternative ramp locations. Further, the project team utilized the ranking from the survey to assign weights to each of the scoring criterion with the highest being worth a maximum of 13 points and the lowest being worth a maximum of 6 points out of 100. Table 4.1 depicts the final criteria and associated weight given to each criterion. It should be noted each of the five (5) ramp alternative locations would have received very similar scores for each of the four criterion that were eliminated (Transportation/Traffic, Noise, Greenhouse Gas Emissions, and Air Quality). 20 of 143 TABLE 4.1 displays the criteria for evaluating alternatives with associated weighting # Criteria Weight Weighted Max 1 Usage/Demand 1.3 13 2 Safety/Convenience 1.3 13 3 Construction Feasibility/Complexity 1.1 11 4 CCC Acceptance 1.1 11 5 Aesthetics 1.1 11 6 Public Input 1.0 10 7 State Parks Concurrence 1.0 10 8 Vulnerability 0.8 8 9 Biological Resources Impact 0.7 7 10 Geotech / Geology 0.6 6 Total 10.0 100 Source: Chen Ryan Associates, June 2019. 4.0 Feasibility Study Results Preferred Alternatives The project team utilized the criteria for evaluating alternative locations to score each of the five (5) alternative locations compared to one another. Summary of the evaluation for each alternative: • North of Pine Avenue – preferred alternative #1. The alternative location scored high across the board with high scores for usage/demand, construction feasibility/complexity, CCC acceptance, public input, State Parks concurrence, and biological resources impact. The only real mark against this alternative is vulnerability. This is because the end of the ramp is at grade and not protected by shoreline protection. However, some of the existing rip-rap could be moved around to enhance this deficiency. • Pine Avenue – This alternative scored lower than North of Pine due to the complexity of constructing the ramp in the narrow area between the existing restroom and the upper sea wall walkway. If would also result in greater impacts to biological resources and require some landform alteration at the end of the ramp. • Cherry Street - lowest score. This alternative scored poorly on usage/demand, safety/convenience, and public input. • Tamarack Avenue Restroom – preferred alternative #2. This alternative location scored second highest overall. 21 of 143 • South of Tamarack Avenue Access Road – This alternative scored lower than the Tamarack Avenue Restroom due to vulnerability (it does not land behind the lower seawall) and safety/convenience (it requires crossing vehicle drive aisle to access the beach and does not allow for ADA access to the existing restroom). Conceptual Design Schmidt Design Group developed a number of rough sketches for the two preferred alternatives (see Appendix D). These were refined utilizing input from the project team and city staff (see Appendix E). Some of the key decisions that were made during this process included the following: • North of Pine Avenue Ramp – o Land the ramp near the existing rip-rap adjacent to the existing restroom. This approach mitigates the vulnerability to raising sea levels and provides access to the ADA compliant restroom. Landing on the sand as shown on some of the initial sketches was not seen as ideal. o Do not include stairs. The project team decided that inclusion of stairs that provide access to a different potion of the beach does not meet the reasonable accommodation requirements of ADA. o Ramp to be 8’ wide. o Maintain existing informal railroad tie access trails at the parking lot. • Tamarack Avenue Restroom Ramp – o Minimize ramp length within the bluffs. This approach lessens impact to biological resources. o Revise existing ramp to existing restroom to be ADA compliant. This allows for ADA access to the existing restrooms and also allows a large portion of the ramp system to be built at-grade (much lower cost) on previously disturbed land. o Ramp to be 8’ wide. Figures 4-7 display the North of Pine Avenue Ramp and Tamarack Avenue Restroom Ramp final concepts and photo simulations. Figures 8 and 9 display the conceptual design character and plant materials for the projects. 22 of 143 Figure 3 – North of Pine Avenue Ramp 23 of 143 Figure 4 – North of Pine Avenue Ramp – Photosimulation 24 of 143 Figure 5 – Tamarack Avenue Restroom Ramp 25 of 143 Figure 6 – Tamarack Avenue Restroom Ramp – Photosimulation 26 of 143 Figure 7 – Conceptual Design Character 27 of 143 Figure 8 – Proposed Plant Materials 28 of 143 Opinion of Probable Construction Costs The project team developed a planning level opinion of probable construction costs for the ramps. The estimated cost, including design and CEQA clearance, was $2.8M for each ramp. A breakdown of costs can be found in Appendix F. CEQA Clearance The project team completed an evaluation of environmental constraints to help transition into the next phase of the project. The biggest constraint are the existing biological resources that would be impacted by construction. However, these impacts can be mitigated. The Environmental Constraints Analysis Table can be found in Appendix G. 29 of 143 P a g e | 20 Carlsbad ADA Beach Access Feasibility Study Appendix A Pedestrian Activity Analysis 30 of 143 CARLSBAD ADA BEACH AND LAGOON ACCESS FEASIBILITY PROJECT PEDESTRIAN ACTIVITY ANALYSIS 9/26/2018 Location Total Pedestrian Counts Peak Hour Peak Hour Volume 7 - Tamarack Blvd Stairway 2,162 7:00 PM 203 8 - Tamarack State Beach Access Road Walkway 1,140 7:00 PM 138 Location Total Pedestrian Counts Peak Hour Peak Hour Volume 1 - Pine Avenue Beach Access Ramp 5,720 7:00 PM 536 2 - Sycamore Avenue Stairway 1,599 2:00 PM 191 3 - Maple Avenue Stairway 1,249 1:00 PM 126 4 - Cherry Avenue Stairway 2,042 7:00 PM 206 5 - Hemlock Avenue Stairway 1,686 4:00 PM 173 6 - Cold-Water Inlet Stairway 1,007 9:00 AM 120 7 - Tamarack Blvd Stairway 3,477 7:00 PM 316 8 - Tamarack State Beach Access Road Walkway 1,758*7:00 PM 215* Location 6 - Cold-Water Inlet Stairway experienced the lowest pedestrian activity with 1,007 pedestrians. 24-Hr Pedestrian Activity - Saturday, August 11, 2018 24-Hr Pedestrian Activity - Friday, August 10, 2018 *Pedestrian volumes obtained using ratios developed based on counts from Friday, August 10th Location 1 - Pine Avenue Beach Access Ramp experienced the highest pedestrian activity with 5,720 pedestrians. 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 1 - Pine Avenue Beach Access Ramp 2 - Sycamore Avenue Stairway 3 - Maple Avenue Stairway 4 - Cherry Avenue Stairway 5 - Hemlock Avenue Stairway 6 - Cold-Water Inlet Stairway 7 - Tamarack Blvd Stairway 8 - Tamarack State Beach Access Road Walkwaypedestrianns in 24 HRBeach Access Location Pedestrian Activity 31 of 143 PROJECT: 1 00:00 →01:00 31 2 01:00 →02:00 33 3 02:00 →03:00 0 4 03:00 →04:00 0 5 04:00 →05:00 2 6 05:00 →06:00 15 7 06:00 →07:00 75 8 07:00 →08:00 189 9 08:00 →09:00 325 10 09:00 →10:00 447 11 10:00 →11:00 361 12 11:00 →12:00 418 13 12:00 →13:00 388 14 13:00 →14:00 410 15 14:00 →15:00 371 16 15:00 →16:00 360 17 16:00 →17:00 363 18 17:00 →18:00 426 19 18:00 →19:00 436 20 19:00 →20:00 536 21 20:00 →21:00 316 22 21:00 →22:00 96 23 22:00 →23:00 69 24 23:00 →00:00 53 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 1- Pine Avenue Beach Access Ramp DAILY LOCATION TOTAL 5720 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 32 of 143 PROJECT: 1 00:00 →01:00 8 2 01:00 →02:00 2 3 02:00 →03:00 0 4 03:00 →04:00 0 5 04:00 →05:00 4 6 05:00 →06:00 6 7 06:00 →07:00 27 8 07:00 →08:00 24 9 08:00 →09:00 71 10 09:00 →10:00 86 11 10:00 →11:00 109 12 11:00 →12:00 91 13 12:00 →13:00 115 14 13:00 →14:00 131 15 14:00 →15:00 191 16 15:00 →16:00 137 17 16:00 →17:00 122 18 17:00 →18:00 129 19 18:00 →19:00 105 20 19:00 →20:00 128 21 20:00 →21:00 64 22 21:00 →22:00 5 23 22:00 →23:00 16 24 23:00 →00:00 28 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 2 - Sycamore Avenue Stairway DAILY LOCATION TOTAL 1599 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 33 of 143 PROJECT: 1 00:00 →01:00 7 2 01:00 →02:00 2 3 02:00 →03:00 0 4 03:00 →04:00 0 5 04:00 →05:00 4 6 05:00 →06:00 2 7 06:00 →07:00 8 8 07:00 →08:00 44 9 08:00 →09:00 55 10 09:00 →10:00 62 11 10:00 →11:00 88 12 11:00 →12:00 96 13 12:00 →13:00 74 14 13:00 →14:00 126 15 14:00 →15:00 116 16 15:00 →16:00 93 17 16:00 →17:00 107 18 17:00 →18:00 124 19 18:00 →19:00 95 20 19:00 →20:00 75 21 20:00 →21:00 54 22 21:00 →22:00 8 23 22:00 →23:00 8 24 23:00 →00:00 1 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 3 - Maple Avenue Stairway DAILY LOCATION TOTAL 1249 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 34 of 143 PROJECT: 1 00:00 →01:00 6 2 01:00 →02:00 4 3 02:00 →03:00 6 4 03:00 →04:00 0 5 04:00 →05:00 0 6 05:00 →06:00 4 7 06:00 →07:00 17 8 07:00 →08:00 67 9 08:00 →09:00 79 10 09:00 →10:00 95 11 10:00 →11:00 121 12 11:00 →12:00 155 13 12:00 →13:00 137 14 13:00 →14:00 158 15 14:00 →15:00 149 16 15:00 →16:00 189 17 16:00 →17:00 180 18 17:00 →18:00 154 19 18:00 →19:00 156 20 19:00 →20:00 206 21 20:00 →21:00 62 22 21:00 →22:00 27 23 22:00 →23:00 23 24 23:00 →00:00 47 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 4 - Cherry Avenue Stairway DAILY LOCATION TOTAL 2042 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 35 of 143 PROJECT: 1 00:00 →01:00 4 2 01:00 →02:00 0 3 02:00 →03:00 0 4 03:00 →04:00 2 5 04:00 →05:00 2 6 05:00 →06:00 3 7 06:00 →07:00 27 8 07:00 →08:00 68 9 08:00 →09:00 57 10 09:00 →10:00 93 11 10:00 →11:00 81 12 11:00 →12:00 121 13 12:00 →13:00 115 14 13:00 →14:00 172 15 14:00 →15:00 150 16 15:00 →16:00 134 17 16:00 →17:00 173 18 17:00 →18:00 145 19 18:00 →19:00 111 20 19:00 →20:00 124 21 20:00 →21:00 39 22 21:00 →22:00 35 23 22:00 →23:00 24 24 23:00 →00:00 6 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 5 - Hemlock Avenue Stairway DAILY LOCATION TOTAL 1686 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 36 of 143 PROJECT: 1 00:00 →01:00 5 2 01:00 →02:00 0 3 02:00 →03:00 0 4 03:00 →04:00 0 5 04:00 →05:00 0 6 05:00 →06:00 3 7 06:00 →07:00 34 8 07:00 →08:00 68 9 08:00 →09:00 111 10 09:00 →10:00 120 11 10:00 →11:00 101 12 11:00 →12:00 49 13 12:00 →13:00 54 14 13:00 →14:00 36 15 14:00 →15:00 48 16 15:00 →16:00 41 17 16:00 →17:00 70 18 17:00 →18:00 63 19 18:00 →19:00 78 20 19:00 →20:00 69 21 20:00 →21:00 32 22 21:00 →22:00 21 23 22:00 →23:00 2 24 23:00 →00:00 2 PACIFIC TECHNICAL DATA, LLC PEDESTRIAN BEACH ACCESS STUDY LOCATION 6 - Cold-Water Inlet Stairway DAILY LOCATION TOTAL 1007 PTD18-0810-02 CARLSBADCITY: SATURDAY - AUGUST 11, 2018 37 of 143 ADA Beach Access - Tamarack Blvd Stairway Fri Aug 10, 2018 Full Length (12AM-12AM (+2)) All Classes (Pedestrians, Pedestrians, Bicycles, Bicycle s) All Channels ID: 553192, Location: 33.147429, -117.345717 Provided by: City of Carlsbad (CA) 1635 Faraday Ave, Carlsbad, CA, 92008, US Leg North South Direction Southbound Northbound Time T App T App Int 2018-08-10 12:00AM 0 0 0 0 0 1:00AM 0 0 0 0 0 2:00AM 0 0 0 0 0 3:00AM 0 0 0 0 0 4:00AM 0 0 0 0 0 5:00AM 1 1 2 2 3 6:00AM 17 17 8 8 25 7:00AM 31 31 35 35 66 8:00AM 29 29 32 32 61 9:00AM 51 51 37 37 88 10:00AM 81 81 45 4 5 126 11:00AM 76 76 86 86 162 12:00PM 100 100 88 88 188 1:00PM 86 86 105 105 191 2:00PM 74 74 86 86 160 3:00PM 69 69 109 109 178 4:00PM 83 83 109 109 192 5:00PM 70 70 97 97 167 6:00PM 70 70 87 87 157 7:00PM 79 79 124 124 203 8:00PM 45 4 5 88 88 133 9:00PM 25 25 19 19 4 4 10:00PM 9 9 1 1 10 11:00PM 3 3 5 5 8 2018-08-11 12:00AM 1 1 1 1 2 1:00AM 2 2 2 2 4 2:00AM 0 0 1 1 1 3:00AM 0 0 0 0 0 4:00AM 1 1 0 0 1 5:00AM 7 7 4 4 11 6:00AM 30 30 9 9 39 7:00AM 59 59 49 4 9 108 8:00AM 71 71 70 70 14 1 9:00AM 91 91 87 87 178 10:00AM 111 111 82 82 193 11:00AM 147 14 7 101 101 24 8 12:00PM 122 122 113 113 235 1:00PM 156 156 142 14 2 298 2:00PM 156 156 168 168 324 3:00PM 113 113 163 163 276 4:00PM 116 116 191 191 307 5:00PM 126 126 143 14 3 269 6:00PM 136 136 162 162 298 7:00PM 117 117 199 199 316 8:00PM 66 66 79 79 14 5 9:00PM 30 30 28 28 58 10:00PM 4 4 19 19 23 11:00PM 0 0 2 2 2 Total 2661 2661 2978 2978 5639 % Approach 100%-100%-- % Total 47.2%4 7.2%52.8%52.8%- Pedestrians 0 0 0 % Pedestrians 0%0%0%0%0% Bicycles 0 0 0 1 of 1538 of 143 % Bicycles 0%0%0%0%0% Pedestrians 2661 2661 2977 2977 5638 % Pedestrians 100%100%100%100.0%100.0% Bicycles 0 0 1 1 1 % Bicycles -0%100%0%0.0% Leg North South Direction Southbound Northbound Time T App T App Int *T: Thru 2 of 1539 of 143 ADA Beach Access - Tamarack State Beach Access Road Walkway Fri Aug 10, 2018 Full Leng th (12AM-9:45AM (+1)) All Classes (Pedestrians, Pedestrians) All Channels ID: 554529, Location: 33.147551, -117.345407 Provided by: City of Carlsbad (CA) 1635 Faraday Ave, Carlsbad, CA, 92008, US Leg North South Direction Southbound Northbound Time T App T App Int 2018-08-10 12:00AM 0 0 0 0 0 12:15AM 0 0 0 0 0 12:30AM 0 0 0 0 0 12:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 1:00AM 0 0 0 0 0 1:15AM 0 0 0 0 0 1:30AM 0 0 0 0 0 1:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 2:00AM 0 0 0 0 0 2:15AM 0 0 0 0 0 2:30AM 0 0 0 0 0 2:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 3:00AM 0 0 0 0 0 3:15AM 0 0 0 0 0 3:30AM 0 0 0 0 0 3:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 4:00AM 0 0 0 0 0 4:15AM 0 0 0 0 0 4:30AM 0 0 0 0 0 4:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 5:00AM 0 0 0 0 0 5:15AM 1 1 0 0 1 5:30AM 1 1 0 0 1 5:45AM 1 1 2 2 3 Hourly Total 3 3 2 2 0 6:00AM 0 0 2 2 2 6:15AM 2 2 1 1 3 6:30AM 0 0 4 4 4 6:45AM 2 2 3 3 5 Hourly Total 4 4 10 10 0 7:00AM 4 4 5 5 9 7:15AM 13 13 3 3 16 7:30AM 15 15 7 7 22 7:45AM 7 7 9 9 16 Hourly Total 39 39 24 24 0 8:00AM 7 7 5 5 12 8:15AM 3 3 10 10 13 8:30AM 5 5 4 4 9 8:45AM 6 6 4 4 10 Hourly Total 21 21 23 23 0 9:00AM 11 11 7 7 18 9:15AM 11 11 5 5 16 9:30AM 18 18 7 7 25 9:45AM 13 13 5 5 18 Hourly Total 53 53 24 24 0 10:00AM 12 12 7 7 19 10:15AM 18 18 11 11 29 10:30AM 13 13 3 3 16 10:45AM 10 10 3 3 13 1 of 1340 of 143 Hourly Total 53 53 24 24 0 11:00AM 16 16 5 5 21 11:15AM 8 8 4 4 12 11:30AM 19 19 7 7 26 11:45AM 14 14 18 18 32 Hourly Total 57 57 34 34 0 12:00PM 4 4 1 1 5 12:15PM 6 6 7 7 13 12:30PM 6 6 5 5 11 12:45PM 9 9 8 8 17 Hourly Total 25 25 21 21 0 1:00PM 3 3 4 4 7 1:15PM 10 10 9 9 19 1:30PM 15 15 5 5 20 1:45PM 0 0 4 4 4 Hourly Total 28 28 22 22 0 2:00PM 8 8 3 3 11 2:15PM 12 12 5 5 17 2:30PM 12 12 18 18 30 2:45PM 1 1 4 4 5 Hourly Total 33 33 30 30 0 3:00PM 13 13 4 4 17 3:15PM 17 17 3 3 20 3:30PM 8 8 4 4 12 3:45PM 14 14 14 14 28 Hourly Total 52 52 25 25 0 4:00PM 20 20 12 12 32 4:15PM 12 12 10 10 22 4:30PM 16 16 8 8 24 4:45PM 10 10 15 15 25 Hourly Total 58 58 45 4 5 0 5:00PM 8 8 4 4 12 5:15PM 16 16 7 7 23 5:30PM 6 6 9 9 15 5:45PM 9 9 3 3 12 Hourly Total 39 39 23 23 0 6:00PM 13 13 4 4 17 6:15PM 6 6 6 6 12 6:30PM 23 23 13 13 36 6:45PM 31 31 4 4 35 Hourly Total 73 73 27 27 0 7:00PM 19 19 19 19 38 7:15PM 12 12 8 8 20 7:30PM 32 32 6 6 38 7:45PM 30 30 12 12 4 2 Hourly Total 93 93 45 4 5 0 8:00PM 24 24 13 13 37 8:15PM 21 21 10 10 31 8:30PM 15 15 2 2 17 8:45PM 1 1 1 1 2 Hourly Total 61 61 26 26 0 9:00PM 3 3 3 3 6 9:15PM 0 0 5 5 5 9:30PM 2 2 6 6 8 9:45PM 1 1 5 5 6 Hourly Total 6 6 19 19 0 10:00PM 0 0 0 0 0 10:15PM 0 0 1 1 1 10:30PM 4 4 2 2 6 10:45PM 4 4 0 0 4 Leg North South Direction Southbound Northbound Time T App T App Int 2 of 1341 of 143 Hourly Total 8 8 3 3 0 11:00PM 0 0 2 2 2 11:15PM 1 1 2 2 3 11:30PM 0 0 0 0 0 11:45PM 0 0 2 2 2 Hourly Total 1 1 6 6 0 2018-08-11 12:00AM 0 0 0 0 0 12:15AM 0 0 0 0 0 12:30AM 0 0 0 0 0 12:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 1:00AM 0 0 0 0 0 1:15AM 0 0 3 3 3 1:30AM 0 0 0 0 0 1:45AM 0 0 0 0 0 Hourly Total 0 0 3 3 0 2:00AM 0 0 0 0 0 2:15AM 0 0 0 0 0 2:30AM 0 0 0 0 0 2:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 3:00AM 0 0 0 0 0 3:15AM 0 0 0 0 0 3:30AM 1 1 3 3 4 3:45AM 1 1 0 0 1 Hourly Total 2 2 3 3 0 4:00AM 0 0 0 0 0 4:15AM 0 0 0 0 0 4:30AM 0 0 0 0 0 4:45AM 0 0 0 0 0 Hourly Total 0 0 0 0 0 5:00AM 0 0 0 0 0 5:15AM 0 0 0 0 0 5:30AM 0 0 1 1 1 5:45AM 3 3 1 1 4 Hourly Total 3 3 2 2 0 6:00AM 1 1 2 2 3 6:15AM 3 3 2 2 5 6:30AM 7 7 4 4 11 6:45AM 7 7 1 1 8 Hourly Total 18 18 9 9 0 7:00AM 7 7 6 6 13 7:15AM 8 8 11 11 19 7:30AM 8 8 8 8 16 7:45AM 7 7 5 5 12 Hourly Total 30 30 30 30 0 8:00AM 8 8 19 19 27 8:15AM 21 21 19 19 4 0 8:30AM 11 11 13 13 24 8:45AM 10 10 5 5 15 Hourly Total 50 50 56 56 0 9:00AM 15 15 12 12 27 9:15AM 14 14 18 18 32 9:30AM 18 18 8 8 26 9:45AM 2 2 1 1 3 Hourly Total 49 4 9 39 39 0 Total 859 859 575 575 14 34 % Approach 100%-100%-- % Total 59.9%59.9%40.1%4 0.1%- Pedestrians 0 0 0 Leg North South Direction Southbound Northbound Time T App T App Int 3 of 1342 of 143 % Pedestrians 0%0%0%0%0% Pedestrians 859 859 575 575 1434 % Pedestrians 100%100%100%100%100.0% Leg North South Direction Southbound Northbound Time T App T App Int *T: Thru 4 of 1343 of 143 P a g e | 21 Carlsbad ADA Beach Access Feasibility Study Appendix B Vegetation Constraints Memorandum 44 of 143 AECOM 401 West A Street Suite 1200 San Diego, CA 92101 www.aecom.com 619.610.7600 tel 619.610.7601 fax Memorandum Various siting options for ADA access to Carlsbad State Beach along Carlsbad Boulevard between Pine Avenue and Tamarack Avenue are currently being considered. One consideration in siting may be quality and density of native vegetation along the existing bluff. To aid in siting considerations that may minimize impacts to native habitats, this qualitative assessment was conducted of bluff habitats supporting native plants along the coastal bluffs in the project vicinity. Bluffs in the project area have received various levels of habitat restoration/enhancement in recent years through the coordinated efforts of the City of Carlsbad, Carlsbad State Park, and community volunteers. These restoration activities have included the installation of irrigation systems, the planting of native species, and the treatment and removal of invasive species. Specific areas within the proposed project area continue to be characterized by sparse vegetation and/or bare patches and/or the presence of non-native or invasive species. This assessment included a field inspection of the site to determine species composition and relative cover values for native plants, non-native plants, and unvegetated areas. Bluff habitats were divided into areas (polygons) of similar cover proportions and depicted on a map (attached). Relative cover values (totaling 100%) were assigned to each polygon by visual inspection of recent aerial imagery (SANDAG 2017) and comparison to a California Native Plant Society cover diagram (https://cnps.org/wp-content/uploads/2018/03/percent_cover_diag-cnps.pdf). Common native species observed in the study area included coast prickly pear (Opuntia littoralis), California fuchsia (Epilobium canum), seacliff buckwheat (Eriogonum parvifolium), California boxthorn (Lycium californicum), coastal goldenbush (Isocoma menziesii), coast cholla (Cylindropuntia prolifera), and California encelia (Encelia californica). Common non-native species observed included, ngaio (Myoporum laetum), sea lavender (Limonium perezii), and natal plum (Carissa macrocarpa). On the basis of the relative cover values, each of the 12 mapped polygons was then ranked from highest potential impact to native plant resources (Rank of 1) to lowest potential impact to native plant resources (Rank of 12) on the basis of the assigned cover value using the following assumptions:  Higher relative cover value of native plant implies higher potential impacts  Higher relative cover value of non-native plants implies lower potential impacts  Higher relative cover value of unvegetated implies lower potential impacts The assigned cover values and overall rank are presented in the attached table, and a graphical representation of the overall ranking is presented in the attached figure. To Matt Capuzzi, Chen Ryan Page 1 CC Subject ADA Accessibility - Vegetation Constraints Review From Cindy Kinkade, AECOM Date December 20, 2018 45 of 143 Vegetation Polygon (North to South) % Cover Native % Cover NonNative % Cover Unvegetated Rank A 20 5 75 8 B 15 5 80 11 C 60 10 30 4 D 35 10 55 6 E 80 0 20 3 F 15 5 80 9 G 15 0 85 10 H 0 60 40 12 I 80 5 15 1 J 80 15 5 2 K 25 15 60 7 L 75 0 25 5 The vegetation assessment provides a ranking for potential habitat impacts associated with construction of ADA access along Carlsbad Boulevard. Polygons with the highest ranking (red on the attached figure) would result in the lowest degree of impact to native and/or dense vegetation along the bluffs, while those with lower rankings (green on the attached figure) represent those areas that should be avoided if feasible. For example, Polygon I has the lowest ranking of 1 and would result in the highest amount of impacts to native and/or dense vegetation, therefore this area should be avoided if possible. Polygon H has the highest ranking of 12 and would result in the least amount of impacts. Impacts to this resource represent one consideration among many, and may help inform siting efforts for the proposed project. Please feel free to contact me at (619) 610-7801 or cindy.kinkade@aecom.com to discuss the project and we will expedite any requests for additional information. Sincerely, Cindy Kinkade AECOM Project Manager Attachments: ADA Accessibility Habitat Value Assessment Map 46 of 143 A C F D E B I G F K J L H ADA ACCESSIBILITY HABITAT VALUE ASSESSMENTI 1:3,000Scale: 1 in = 250 feet 250 0 250 FeetPath: P:\_6058\60586864_CbadADABeach\900-CAD-GIS\920 GIS\map_docs\mxd\Carlsbad Habitat Value Rank.mxd, paul.moreno, 12/20/2018, 3:13:10 PMSource: SANDAG 2017 Rank % Cover Native% Cover NonNative% Cover UnvegetatedVegetation Polygon0 60 40 H 15 5 80 B 15 0 85 G 15 5 80 F 20 5 75 A 25 15 60 K 35 10 55 D 75 0 25 L 60 10 30 C 80 0 20 E 80 15 5 J 80 5 15 I 47 of 143 P a g e | 22 Carlsbad ADA Beach Access Feasibility Study Appendix C Existing Conditions Analysis 48 of 143 Carlsbad ADA Beach and Lagoon Access Feasibility Study49 of 143 Carlsbad ADA Beach and Lagoon Access Feasibility Study50 of 143 Carlsbad ADA Beach and Lagoon Access Feasibility Study51 of 143 Carlsbad ADA Beach and Lagoon Access Feasibility Study52 of 143 Carlsbad ADA Beach and Lagoon Access Feasibility Study53 of 143 P a g e | 23 Carlsbad ADA Beach Access Feasibility Study Appendix D Pine Avenue and Tamarack Avenue Ramp Options 54 of 143 55 of 143 56 of 143 57 of 143 58 of 143 Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE :CARLSBAD BEACH AND LAGOON CARLSBAD, CA Project Number: 18-106 Date: March 6, 2019 TAMARACK - OPTION 1 (10’ wide) (30) RELOCATE EXISTING BENCHES RELOCATE EXISTING SIGNAGE EXISTING PAY STATION (25)(20)(20)(15)(15) (30)(35)(25) 59 of 143 Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE :CARLSBAD BEACH AND LAGOON CARLSBAD, CA Project Number: 18-106 Date: March 6, 2019 TAMARACK - OPTION 2 (6’ wide) (30) (31) (30) (25) (25) (20) (20) (20) (35) (35) 60 of 143 Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : Project Number: 18-106 Date: February 20, 2019 N. Pine Street - Option 1 Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE :CARLSBAD BEACH AND LAGOON CARLSBAD, CA Project Number: 18-106 Date: March 6, 2019 TAMARACK - OPTION 2 (10’ wide) (30) (30)(31) (30) (25)(25) (20) (20) (20) (35) (35) 61 of 143 P a g e | 24 Carlsbad ADA Beach Access Feasibility Study Appendix E Pine Avenue and Tamarack Avenue Ramps 62 of 143 63 of 143 Z>Kdd>,Zy/^d/E'd>y/^d/E'dhZ&y/^d/E't>>dKZD/EZ>^Kh>sZEt/DWZKsDEdZy/^d/E'^,KtZ^ΘW>Z>KddZ^,,Zy/^d/E'^t>>y/^d/E'>/&'hZdKtZEt^d/Z^y/^d/E'Ws/E'WKZd/KEK&Wd,tzdKKE'ZWKZd/KEK&Wd,tzdK>sdKsZ^>KW;ϯϱͿ;ϯϬͿ;ϯϬͿ;ϯϱͿ;ϮϱͿ;ϮϬͿнϯϮ;ϮϱͿ;ϮϱͿнϯϳнϯϵнϯϵ͘ϲϳ͘ϱйнϯϱ͘ϴϱнϮϵ͘ϲϮϱнϮϳ͘ϯнϮϮ͘ϲϱϳ͘ϱйнϮϬ͘ϯϱнϭϵy/^d/E'Z^dZKKDнϯϮy/^d/E'&Eϴ͛ͲϬ͟ZDWKE^dZhdhZ>K>hDEEtZd/E/E't>>sZ/^ϭϮ͟ͲϰϮ͟,dZ>/'EZKdK>>Kt&KZW^dZ/E^/t><ydE^/t><dKWZ</E'y/^d/E'W>EdZEtW>Ed/E'Zt/d,WZKdd/sZ/>/E'y/^d/E'>h&&dKZD/EнϮϰ͘ϵϳϱнϯϯ͘ϵϱϭϬ͛ͲϬ͟ZDWKE'ZWнdtϮϰнdtϮϰy/^d/E'^dt>>dKZD/Ey/^d/E'^/t><dKZD/Ey/^d/E''hZZ/>/E'dKZD/E/QNIDBS-TLADQ #@SD,@QBG Tamarack RampCarlsbad Beach and LagoonCarlsbad, CA    6&$/(Z>^,E>'KKEZ>^͕WƌŽũĞĐƚEƵŵďĞƌ͗ϭϴͲϭϬϲĂƚĞ͗Ɖƌŝůϱ͕ϮϬϭϵdDZ<ZDW,^^64 of 143 P a g e | 25 Carlsbad ADA Beach Access Feasibility Study Appendix F OPCC and Structures Estimate 65 of 143 Carlsbad ADA Beach Access Feasibility Study Opinion of Probable Construction Costs Type Raised ramp (1) supported on pile extensions at each landing Lump Sum Site Prep, Clearing and Grubbing, Traffic Control, Staging, Erosion Control, Staking, Utility Adjustments, BMPs Lump Sum Landscape, Irrigation, Custom Railings, Etc. Lump Sum CEQA and PS&E Lump Sum TOTAL Cost includes 25% contingency Cost does not include escalation $2,800,000.00 $1,700,000.00 $300,000.00 Civil Landscape & Aesthetics Engineering & Environmental $500,000.00 $300,000.00 ADA Beach Access from Carlsbad Structural 66 of 143 Carlsbad ADA Beach Access Feasibility StudyPreliminary Structures Cost EstimateD. Kasawdish2/20/20191. ADA Beach Access from Carlsbad BoulevardStructure Type: Raised ramp supported on pile extension at each landing.Ramp Length476ftRamp Width10ftAs requested by City during February PDT meetingRamp Area=4,760 SFCost/ SF= 325$ Structure Cost=1,547,000$ For Budget, Use1,600,000$ Based on previous projects with similar structure type and Caltrans Comparative Bridge Costs, scaled by the appropriate Bridge Cost index ratio. 48" CIDH Piles assumed at each landing. Includes 25% ContingencyBased on information provided by Chen Ryan Associates via email on 1/2/19.67 of 143 P a g e | 26 Carlsbad ADA Beach Access Feasibility Study Appendix G Environmental Constraints Table 68 of 143 Carlsbad ADA Beach Access Feasibility Study – Environmental Constraints Analysis Table 1 Alternatives Summary The Pine Avenue Americans with Disabilities Act (ADA) Ramp project would involve constructing an ADA compliant ramp that begins at the parking lot north of the intersection of Pine Avenue and Carlsbad Boulevard. The 389-foot ramp would change direction once, extending the pathway southward within the bluffs. The ramp would be designed with an incline of 7.8 percent. One bench would be installed at the top of the ramp to provide a viewing point for the public. The ramp would be elevated as it descends the bluff, ranging at distances of approximately 2 to 9 feet above the existing bluff below. Two or three disabled parking places would be designated in the existing parking lot. The proposed Tamarack Avenue ADA Ramp is approximately 3,500 feet south of the Pine Avenue ADA Ramp, across from the intersection of Tamarack Avenue and Carlsbad Boulevard. The ramp would begin at the top of the bluff near existing facilities (i.e., showers, plaza, and restrooms) and would extend southward, parallel to the existing access road to the California State Parks (State Parks) parking lot. Current facilities at this access point are not ADA accessible. Construction of the Tamarack Avenue ADA Ramp would create an ADA compliant pathway and would generally improve public access to the beach and Lower Sea Wall at this access point. The existing road/sidewalk south of the proposed ramp would remain the same. Additionally, the existing staircase located perpendicular to the new ramp would be reconstructed. A portion of the ramp would be elevated along the bluff (approximately 60 percent) ranging between 2 and 5 feet above the existing bluff. The ramp would be 196 feet, starting at the access to the existing restroom, and have an incline of 7.5 percent. The existing ramp down to the restrooms would also be rebuilt to be ADA compliant. The design of the Tamarack Avenue Ramp uses existing access points and disturbed areas to the extent possible in order to minimize impacts to the previously undisturbed bluff. Issue Area Existing Conditions/Assumptions Pine Avenue ADA Ramp Tamarack Avenue ADA Ramp Constraints Summary Aesthetics · The existing bluff is mostly unvegetated at the proposed Pine Avenue ADA Ramp location, while the majority of the bluff is vegetated (planted) near the Tamarack Avenue ADA Ramp. · There are no designated scenic resources in the area. · Construction of the ramp would begin at the existing parking lot elevation (i.e., would not rise higher than current bluff elevation). · Landscaping of native vegetation would be established adjacent to ramp. · Design would be less intrusive compared to other existing structures of stairs along this segment of beach, since this ramp would be built closer to grade along the slope of the bluff as compared to existing staircases along the coastline. · Construction of the ramp and staircase would begin at the same level of existing facilities and would not rise higher than the current bluff elevation. · Landscaping of native vegetation would be established adjacent to ramp. · The existing staircase would be updated, which is built to grade along the bluff. · Overall, the difference in aesthetics between both options would be minimal aside from the existing staircase which would remain built to grade along the bluff. However, the Tamarack Avenue ADA Ramp incorporates planting to complement the existing facilities area. The raised structures could be perceived as large from vantage points along the beach. However, these structures would be less intrusive compared to the existing staircases along this section of coastline and impacts would be minimal. · Both options would not interfere with pedestrian/traffic views of the coastline. Air Quality · It is assumed that no operational sources are associated with either option; therefore, only construction impacts are evaluated. · Sensitive receptors are not located in the vicinity of the proposed projects. · Potential impacts due to construction would be temporary. Standard construction equipment would be used and applicable avoidance and minimization measures would be implemented. · Potential impacts due to construction would be temporary. Standard construction equipment would be used and applicable avoidance and minimization measures would be implemented. · Potential air quality impacts related to construction of the proposed ramps would be similar between the two projects. · Air quality emissions associated with the proposed projects include emissions from construction. However, operations associated with construction would minimize emissions through standard construction measures, storm water pollution prevention plan measures, and best management practices. · It is assumed impacts would not occur to sensitive receptors as none are located in the vicinity of the proposed projects. 69 of 143 Carlsbad ADA Beach Access Feasibility Study – Environmental Constraints Analysis Table 2 Issue Area Existing Conditions/Assumptions Pine Avenue ADA Ramp Tamarack Avenue ADA Ramp Constraints Summary Biological Resources · In the Vegetation Constraints Review Memo prepared by AECOM for the proposed projects, the North of Pine Avenue Ramp footprint evaluated along this section of bluff is identified as 20% natives, 5% nonnatives, and 75% unvegetated (AECOM 2018a). This area has a ranking of 8 out of 12 (where a rank of 12 is the lowest potential impact to native plant resources). The Tamarack Avenue Ramp footprint covers two areas identified in the memo, known as I and J. These areas encompass 80% native, 5% nonnative, 15% unvegetated and 80% native, 15% nonnative, 5% unvegetated, respectively. They rank 1 and 2 for potential habitat impacts (where a rank of 1 is the highest potential to impact native plant resources). · Endangered, threatened, or proposed for listing/rare wildlife are not known to use the proposed project site since habitat is low quality, fragmented vegetation interspersed with sandy bluff too minimal to support species. · Implementation of both projects would avoid the aquatic environment. · This area is not located within the City of Carlsbad’s Habitat Management Plan (HMP) and is not designated as a significant wildlife corridor (City of Carlsbad 2004). · Equipment staging during construction would most likely occur in existing developed areas (e.g., parking lot at top of ramp). · Impacts to vegetation may occur with installation of the ramp (e.g., vegetation removal). · Once constructed, the shadow created by the ramp may shade vegetation and could potentially inhibit plant growth. · Equipment staging during construction would most likely occur in existing developed areas. · Impacts to vegetation may occur with installation of the ramp and staircase (e.g., vegetation removal). · Once constructed, the shadow created by the elevated portions of the ramp may shade vegetation and could potentially inhibit plant growth. The existing staircase that would be updated as part of this design is currently at grade and is not expected to contribute to shadowing effects from vegetation. · The Pine Avenue ADA Ramp would have a slightly larger impact area compared to the Tamarack Avenue ADA Ramp as the design of the ramp is primarily focused on an undisturbed segment of bluff. Design of the Tamarack Avenue ADA Ramp incorporates the existing access footprint to the extent possible. For example, the existing staircase at the Tamarack Avenue ADA Ramp is in need of repair and upgrades are proposed to the existing structure within the previously disturbed footprint. Additionally, the new ramp which would provide access to the existing restrooms and associated improvements are within previously disturbed areas. · In both options, vegetation is proposed along the access ramp. The ramp footprint in the Pine Avenue ADA Ramp would impact more undisturbed bluff than the Tamarack Avenue ADA Ramp. However, while more undisturbed bluff is expected to be impacted at North of Pine Avenue, this area is of lesser habitat value than the cover type existing in the vicinity of the Tamarack Avenue ADA Ramp (AECOM 2018a). The Tamarack Avenue ADA Ramp design uses existing infrastructure at the staircase and north of the public facilities, which would minimize impacts to previously planted vegetation. Since vegetation in the Tamarack Avenue Ramp footprint has grown in successfully, this recruitment shows temporary vegetation impacts along the bluff could be successfully established post-construction. Best management practices would be implemented to ensure plant establishment along the bluff in both locations. · Neither proposed project footprint functions as a terrestrial wildlife movement corridor. The movement of marine species would not be affected by the proposed projects’ activities, as there would be no permanent or temporary blockage of the open water corridor. No impacts are anticipated to wildlife movement/corridors with implementation of either project. · Avoidance and minimization measures would be implemented to minimize potential impacts to wildlife species, if found, such as clearance surveys for birds or other sensitive species (e.g., silvery legless lizard, a California Department of Fish and Wildlife species of special concern) as required, or vegetation removal outside of the breeding season. Cultural/Tribal Cultural Resources · A previous records search was conducted in the vicinity of the proposed projects for the Carlsbad Boulevard and Tamarack Avenue Improvement Project in 2017 (AECOM 2018b). The records search area encompassed all of the Tamarack Avenue ADA Ramp option and a portion of the Pine · The proposed project would be constructed on previously undisturbed bluffs known as the Santiago Formation (AECOM 2018b). Potential for impact could occur if a previously unknown · For the most part, the proposed project would be constructed on previously disturbed ground, although excavation for footings/foundations could extend into previously undisturbed bluff · Standard surveys, analysis, and mitigation measures (e.g., consulting a qualified archaeologist and a Native American representative, if applicable) would be implemented prior to and during construction because cultural sites have been identified within a 0.5-mile radius of the proposed project areas, and the coastal region of 70 of 143 Carlsbad ADA Beach Access Feasibility Study – Environmental Constraints Analysis Table 3 Issue Area Existing Conditions/Assumptions Pine Avenue ADA Ramp Tamarack Avenue ADA Ramp Constraints Summary Avenue ADA Ramp footprint. The previous records search indicated 20 studies have been conducted, four cultural resources were previously recorded, and one cultural resource was identified during a pedestrian survey, all within a 0.5 mile vicinity of the proposed projects. After consulting with the Native American Heritage Council, it was determined that no Native American places or sites were on file in the vicinity of the proposed project sites. · One cultural resource has been identified within the Tamarack Avenue ADA Ramp option footprint, known as the Tamarack Avenue Comfort Station. A historical background study and determination of eligibility was prepared in 2016 and indicated that the Comfort Station is potentially eligible for listing on the California Register of Historical Resources and National Register of Historic Places (AECOM 2018b; Bevil 2016). · Separate record and Sacred Lands File searches could be completed to confirm cultural and/or tribal cultural resources are not in the proposed footprint for the Pine Avenue ADA Ramp. Given the recent results in the Cultural Resources Phase 1 Survey Report conducted for the Carlsbad Boulevard and Tamarack Avenue Improvement Project, it is assumed cultural and/or tribal cultural resources are not in the vicinity of the Pine Avenue ADA Ramp. resource was discovered during ground disturbing activities. formations (e.g., Santiago Formation). Potential for impact could occur if a previously unknown resource was discovered during ground disturbing activities. San Diego County retains a high level of cultural sensitivity to Native American tribes (AECOM 2018b). · If feasible, project design would avoid the Comfort Station at the Tamarack Avenue ADA Ramp; the proposed project would provide ADA access as well as improved general public access to this structure. · The Pine Avenue ADA Ramp may present more of an opportunity to encounter unknown resources since more ground disturbance would occur on undeveloped bluff. Both options would follow standard procedures for protecting cultural resources. Geotechnical/G eology · There are no active faults identified through Carlsbad, and the California Geologic Survey does not include Carlsbad on list of cities affected by the Alquist-Priolo Earthquake Fault Zones. However, Carlsbad is in a seismically active region and is subject to ground-shaking during an earthquake. · Geotechnical stability analyses were performed, indicating the coastal bluffs in the project area currently have adequate factors of safety against deep instability and would not be located on an unstable geologic unit or on expansive soils (AECOM 2016a). · As stated in the General Plan, the city of Carlsbad is located within the coastal portion of the Peninsular Ranges Geomorphic Province, a region characterized by northwest-trending structural blocks and intervening fault zones (City of Carlsbad 2015a). The proposed project areas consist of fill material and terrace deposits where the base of the bluffs is characterized by the Santiago Formation and relatively resistant sandstone forms the lower · The proposed project would be constructed on a previously undeveloped site where soil removal would be required to install piles for the elevated ramp design. Potential impacts could occur with soil removal, which would be required to install piles for the elevated ramp design. · The majority of the proposed project would be constructed on a previously developed site and generally the same footprint as the existing walkway and staircase. Potential impacts could occur with soil removal, required to install piles for the elevated ramp design. · Although loss of topsoil from project implementation is not anticipated to be substantial, and erosion would most likely decrease with project implementation due to reduced use of informal trails, in order to minimize the potential impacts of soil erosion or the loss of topsoil, avoidance and minimization measures would be adopted with implementation of both options (e.g., erosion control and revegetation/planting plan, City review of site grading plan to ensure compliance with code requirements). The proposed project may decrease informal trail use, especially in the vicinity of the Pine Avenue ADA Ramp, which contributes to substantial soil erosion estimated to be approximately 1 foot per year along the northern part of the bluffs (AECOM 2016b). · Both options would adhere to all applicable building and seismic codes and regulations therefore, not exposing people or structures to potential substantial adverse effects, including risk of loss, injury, or death due to severe ground shaking. · Due to the nature of the site as described under existing conditions, impacts related to increased slope instability, 71 of 143 Carlsbad ADA Beach Access Feasibility Study – Environmental Constraints Analysis Table 4 Issue Area Existing Conditions/Assumptions Pine Avenue ADA Ramp Tamarack Avenue ADA Ramp Constraints Summary portion of the bluff (AECOM 2016a). Pleistocene terrace deposits compose the upper portion of the bluff, above an elevation of approximately 8 to 12 feet above mean sea level (AECOM 2016a). landsides, or other adverse seismic-induced geologic hazards are not anticipated. Greenhouse Gas Emissions · It is assumed that no operational sources are associated with either project; therefore, only construction impacts are evaluated. · The City of Carlsbad adopted a Climate Action Plan (CAP) that outlines actions that the city will undertake to achieve its proportional share of the state greenhouse gas (GHG) emissions reductions. The CAP is a plan for the reduction of GHG emissions in accordance with California Environmental Quality Act (CEQA) Guidelines Section 15183.5. Pursuant to CEQA Guidelines Sections 15064(h)(3), 15130(d), and 15183(b), a project’s incremental contribution to a cumulative GHG emissions effect may be determined not to be cumulatively considerable if it complies with the requirements of the CAP. · Standard construction equipment would be used and standard emissions controls would be implemented. · Standard construction equipment would be used and standard emissions controls would be implemented. · GHG emissions related to construction of the project would be similar between projects. Similar construction equipment would likely be used, and vehicle trips to the construction site would be similar. · Both options are expected to be in compliance with the Carlsbad CAP and would not emit at or above the CAP screening threshold of 900 metric tons of CO2 equivalent, as outlined in the CAP Consistency Checklist. Additionally, both options’ incremental contribution to a cumulative GHG emissions effect would not be considered cumulatively considerable, because they would comply with requirements of the CAP. Land Use · Both proposed projects are surrounded by residential development to the east and the Pacific Ocean to the west. Both options are in the coastal zone and subject to regulations per the California Coastal Act. · Proposed ramp improvements are located at Carlsbad State Beach, which State Parks has jurisdiction over. · The proposed project would comply with applicable land use policies and guidelines. · The proposed project would comply with applicable land use policies and guidelines. · Both options would conform to applicable land use policies and guidelines (e.g., Coastal Act) and appropriate resource agencies would be involved during the permitting process (e.g., California Coastal Commission, California State Parks). · Proposed ramps would establish ADA compliant features along the bluff, improve general public access to the beach, and would be consistent with existing land use and recreation for the area. Noise · It is assumed that no operational sources are associated with either option, therefore only construction impacts are evaluated. · The closest noise sensitive receptors to the Pine Avenue ADA Ramp is a single-family residential structure located approximately 150 feet north of the site and multi-residential units approximately 150 feet east of the nearest construction boundary. · The closest noise sensitive receptor to the Tamarack Ramp Avenue option is a multi- residential structure located approximately 250 feet southeast of the project limits. · Given the open space and recreational nature of both proposed project sites, public using the beach could be considered a sensitive noise receptor during construction. · Noise impacts associated with construction would be temporary and standard construction equipment would be used. · Noise impacts associated with construction would be temporary and standard construction equipment would be used. · Construction equipment and techniques used would be similar or the same for both projects. Potential impacts due to construction noise would be similar or the same for both projects. · During construction of both projects, noise minimization measures would be implemented and local noise ordinance would be followed as detailed in Chapter 8.48, Noise of the City of Carlsbad Municipal Code, which sets limitations for construction hours. · While the public using the beach during construction hours may experience higher noise levels anticipated with construction, other portions of the beach where temporary construction noise could be avoided will remain open for use. Recreation · Existing informal trails are located along the Pine Avenue ADA Ramp footprint. · Construction would temporarily interrupt access via informal trails. During construction, multiple access points along the coastline · Construction would temporarily interrupt recreation and access to the beach and facilities at this location. Additionally, multiple · Localized recreation and public access would be temporarily interrupted during construction of both projects; however, impacts between the two projects would be similar. Portions of parking lots may be 72 of 143 Carlsbad ADA Beach Access Feasibility Study – Environmental Constraints Analysis Table 5 Issue Area Existing Conditions/Assumptions Pine Avenue ADA Ramp Tamarack Avenue ADA Ramp Constraints Summary · There are multiple existing access points along this portion of coastline, none of which are currently ADA compliant. could continue to be used to access the beach. access points along the coastline could continue to be used in order to access the beach instead of the current access point at Tamarack Avenue. temporarily closed in order to stage equipment. Numerous existing access points between the two proposed project sites would remain available for use during construction, including the ramp at Pine Avenue and four staircases. These existing access areas would remain open during construction and would continue to provide adequate access to the beach during construction. If feasible, proposed project work would be conducted outside of the busy summer season. · Post-construction, recreation and access would be enhanced via the proposed ADA compliant ramps. Sea Level Rise/Storm Damage Vulnerability · Both structures are subject to influence from sea level rise but would be constructed along the existing bluff above the elevation of the existing walkway, which is protected by a sea wall. · To the extent practicable, structures have been designed to provide resilience to sea level rise scenarios. · To the extent practicable, structures have been designed to provide resilience to sea level rise scenarios. · Structures are designed to be above the elevation of an existing boardwalk and behind a protective sea wall, which protects from potential storm damage and sea level rise influence. Transportation/ Traffic · It is assumed that no operational sources are associated with either option, therefore only construction impacts are evaluated. · Increased traffic to the site due to improved access is assumed to be minimal and most likely by existing users or residents using this improved route to access the beach, because the proposed project would create an ADA compliant ramp and safer/more direct pedestrian access. · Traffic may be temporarily interrupted during construction. · Traffic may be temporarily interrupted during construction. · Applicable measures would be implemented during construction to avoid and/or minimize temporary traffic impacts (e.g., timing of project work, traffic control plan). References AECOM 2016a Geotechnical Investigations Carlsbad Boulevard and Tamarack Avenue Pedestrian Improvements Project. 2016b Tamarack Area Coastal Improvements Project Mitigated Negative Declaration. 2018a ADA Accessibility – Vegetation Constraints Review. 2018b Cultural Resources Phase I Survey Report for the Carlsbad Boulevard and Tamarack Avenue Improvement Project. Bevil, A.D. 2016 The Tamarack Avenue Comfort Station at Carlsbad State Beach Historical Background Study and Determination of Eligibility. On file at the California Department of Parks and Recreation Southern Service Center. City of Carlsbad 2004 Habitat Management Plan for the Natural Communities in the City of Carlsbad. Available at:http://www.carlsbadca.gov/civicax/filebank/blobdload.aspx?BlobID=27193. Accessed August 2016. 2015a General Plan. Available at:http://www.carlsbadca.gov/services/depts/planning/general.asp. Accessed July 2019. 2015b General Plan and Climate Action Plan Final Environmental Impact Report. Available at:http://www.carlsbadca.gov/civicax/filebank/blobdload.aspx?BlobID=28464. Accessed August 2016. 73 of 143 Prepared for: Community Services Parks & Recreation Department City of Carlsbad 1635 Faraday Avenue Carlsbad, CA 92008-7314 Prepared by: 3900 5th Avenue, Suite 310 San Diego, CA 92103 December 2019 Trail Connectivity to Tamarack State Beach Feasibility Study Final Report 74 of 143 P a g e | i Trail Connectivity to Tamarack State Beach Feasibility Study Table of Contents 1.0 Introduction .................................................................................................................... 2 1.1 Overview ............................................................................................................................... 2 1.2 Project Background ............................................................................................................... 2 1.3 Project Study Area ................................................................................................................ 2 2.0 Existing Conditions ..................................................................................................... 4 Carlsbad Blvd Bridge ........................................................................................................ 4 Clearance under Carlsbad Blvd Bridge ............................................................................. 5 Wave run-up study .......................................................................................................... 5 3.0 Feasibility Study Approach ......................................................................................... 6 Trail Connectivity to Tamarack State Beach .................................................................... 6 4.0 Feasibility Study Results ............................................................................................. 8 Proposed Structure .......................................................................................................... 8 Opinion of Probable Construction Costs ......................................................................... 9 CEQA Clearance ............................................................................................................. 10 5.0 Conclusion ............................................................................................................... 14 List of Figures Figure 1 Project Study Area .............................................................................................................. 3 Figure 2 Open Walkway .................................................................................................................... 7 Figure 3 ADA Crossing Under Exist Bridge ........................................................................................ 7 Figure 4 ADA Crossing Under Exist Road .......................................................................................... 8 Figure 5 Cold Water Cut-Cover Tunnel Rendering ......................................................................... 11 Figure 6 Cold Water Cut-Cover Tunnel 3-D Simulation .................................................................. 12 Appendices Appendix A Final Wave Runup Study Appendix B Cost Estimate and Structures Estimate Appendix C Environmental Constraints Table 75 of 143 P a g e | 2 Trail Connectivity to Tamarack State Beach Feasibility Study 1.0 Introduction 1.1 Overview The City of Carlsbad Community Services – Parks & Recreation Department commissioned a feasibility study for a connection between the North Shore Agua Hedionda Lagoon Trail and Tamarack State Beach via pedestrian walkway, tunnel, or at grade crossing. Purpose The purpose of the project is to provide access for all pedestrians, regardless of ability, to one of the area’s premier beaches. The importance of this project cannot be understated as it will allow the community to enjoy a beautiful natural-resource that is unique to the region. The proposed project promotes the spirit and vision of both the California Coastal Act and the Americans with Disabilities Act. 1.2 Project Background Trail Connectivity to Tamarack State Beach, Project No. 40631 The Trail Connectivity to Tamarack State Beach project is located at the Cold-Water Inlet Bridge (bridge) on Carlsbad Boulevard, south of Tamarack Avenue. The bridge is one of two waterway openings that connect the Agua Hedionda Lagoon and the Pacific Ocean. The North Shore Agua Hedionda Lagoon Trail runs along the north side of the lagoon. The trail’s western terminus is at the north side of the bridge, where a steep dirt pathway leads up to the east side of Carlsbad Boulevard. Tamarack State Beach lies west of Carlsbad Boulevard and north of the bridge. Currently, there is no connection between the North Shore Trail and Tamarack State Beach. In the existing condition, people using the trail who want to access the beach must climb the steep dirt trail at the terminus of the North Shore Trail, walk uphill (approximately 700 feet) along the east side of Carlsbad Boulevard to Tamarack Avenue, cross Tamarack Avenue, cross Carlsbad Boulevard, and walk down a steep asphalt pathway to the Tamarack State Beach. This circuitous route makes for a difficult connection between these two important natural resources. The project’s main objective is to evaluate the feasibility of constructing a tunnel or undercrossing to connect the North Shore Lagoon Trail to Tamarack State Beach. A number of alternatives were considered and evaluated to determine engineering feasibility. The project goal is to develop a preferred alternative for the connection between the North Shore Lagoon Trail and Tamarack State Beach. 1.3 Project Study Area The project study area is at and adjacent to the north side of the existing bridge. Figure 1 displays the project study area. 76 of 143 P a g e | 3 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 1 Project Study Area Location of proposed crossing 77 of 143 P a g e | 4 Trail Connectivity to Tamarack State Beach Feasibility Study 2.0 Existing Conditions Carlsbad Boulevard is positioned on a coastal bluff and is elevated from the coastal parking lot. Approximate elevations of key features in the study area (relative to NAVD88, ft) are as follows:  Tamarack State Beach Parking Lot: +12 to +15 (west to east)  Carlsbad Boulevard (in vicinity of stairs at the north side of the bridge): +27  Cold Water bridge soffit: +17  Tamarack back beach: +12 Jurisdictionally, the City owns and operates the roadway and California State Parks owns and manages the parking lot and beach at Tamarack State Beach. The parking lot is currently subject to seasonal flooding and rip-rap has been placed on the seaward edge to help protect the parking lot during these events. Wave overtopping of the parking lot was evident during a site visit on November 1, 2018 as over-washed sand and marine debris were present on the western side of the lot. A vertical seawall begins immediately north of the parking lot, which spans about 3,500 feet to the north where it terminates in the vicinity of Pine Avenue. The width of Tamarack State Beach is controlled by regional and local beach nourishment activities. Regionally, beach widths have been impacted by two large scale beach nourishment efforts conducted by SANDAG in 2001 and 2012. These projects are known as the Regional Beach Sand Project I and II, respectively. These projects placed about 2.1 million and 1.5 million cubic yards of sand on San Diego beaches. Placement of sand at two beaches upcoast from Tamarack State Beach (i.e. North Carlsbad and Oceanside placement sites) have impacted beach width and shape at Tamarack State Beach over time. These upcoast placement sites received a total of 646,000 cy and 512,000 cy of sand in 2001 and 2012, respectively from these regional projects. Locally, Tamarack beach is directly affected by the placement of sand from Agua Hedionda Lagoon maintenance dredging activities. The program bypasses an average of 135,000 cy (during the period of 2001 to 2015) of sand from the flood shoal of the lagoon biennially. Dredged sand is placed at three beach sites each year as follows: 1) north of the cold-water jetties within the study area, 2) south of the cold-water jetties and 3) south of the warm water jetties. The direct placement of sand on this beach impacts width and shape. Carlsbad Blvd Bridge The existing Carlsbad Blvd Bridge is a simple span cast in-place prestressed (CIP/PS) concrete box girder. It is approximately 201-foot long, 82 feet wide. The superstructure consists of 8-foot deep twin box girders. Carlsbad Blvd within the project limits is a 4-lane road, two lanes in each direction, separated by a raised median within the bridge limits. The raised median ends at the bridge northern approach slab. Class II bike lanes and sidewalk separated by concrete barriers are provided on both sides of the road. The barrier is provided only within the limits of the bridge, and a guard rail is provided along the western sidewalk beyond the northern bridge approach slab. 78 of 143 P a g e | 5 Trail Connectivity to Tamarack State Beach Feasibility Study Clearance under Carlsbad Blvd Bridge Vertical clearance under the bridge was a critical consideration, based on water surface elevations (WSEs) in the lagoon. Based on the City of Carlsbad (City) Sea Level Rise Vulnerability Assessment report dated December 2017, and the existing Carlsbad Boulevard bridge elevation, the following vertical clearance is available under the existing bridge: TABLE 1 – CLEARANCE UNDER CARLSBAD BLVD BRIDGE Condition WS Elevation (ft) @ Lagoon Clearance Under Bridge (ft) WS Elevation (ft) @ Beach Current Mean High-Water Line 4.44 12.18 - Year 2050 Mean High-Water Line (ft) 6.04 10.58 - Year 2100 Mean High-Water Line (ft) 11.04 5.58 - Current Water Surface Elevation (ft), (100-Year Storm) 6.90 9.72 11 Year 2050 Water Surface Elevation (ft), (100-Year Storm) 8.50 8.12 13 Year 2100 Water Surface Elevation (ft), (100-Year Storm) 13.50 3.12 18 Source: Chen Ryan Associates, June 2019. As seen in the table above, clearance under the Carlsbad Blvd bridge is anticipated to decrease from 12.18 feet under Current Mean High-Water Line conditions to 5.58 feet under Year 2100 Mean High-Water Line conditions. Wave run-up study The City of Carlsbad Sea Level Rise Vulnerability utilized the CoSMoS model which was developed as a regional model and for planning purposes, therefore, site specific information was not accurate. Therefore, a wave run-up study that focused on the project study area was developed. The study evaluated existing and potential future coastal hazards (i.e. flooding and inundation) that may impact the proposed trail connection. The study identified wave runup elevations to be approximately 2 feet higher than WSE for the same return period. See Appendix A for wave run-up study. 79 of 143 P a g e | 6 Trail Connectivity to Tamarack State Beach Feasibility Study 3.0 Feasibility Study Approach This chapter describes the various analyses performed as part of the trail connectivity feasibility evaluation. Trail Connectivity to Tamarack State Beach Multiple alternatives were considered to provide a trail connection in the vicinity of the Cold-Water Inlet. The crossing can either be underneath the existing bridge or under the existing road, north of the bridge. An overcrossing alternative was not considered due to significant visual impacts. The vertical clearance underneath the bridge was a critical consideration, considering water surface elevations (WSEs) in the lagoon. The following alternatives were considered for a trail connection at the north side of the existing bridge: 1. Pedestrian Bridge (Beneath Exist Carlsbad Blvd Bridge) A bridge supported on piles spanning beneath the existing Carlsbad Blvd Bridge, in front of the northern abutment was considered. Based on Table 1, the maximum available clearance under the bridge for the existing Mean High-Water condition is 12.18 ft. Considering the following requirements, a pedestrian bridge requires a minimum of 12.5 ft vertical clearance. Therefore, this alternative is not feasible.  8’-0” Overhead Clearance  2’-6” Structure Depth  2’-0” Minimum Vertical Freeboard 2. Open Walkway Walkway on a retaining wall beneath Carlsbad Blvd Bridge is a viable, cost effective option for this alternative. However, this alternative is not preferable due to the following:  Hydraulics Impact o Scour o Potential Back Water Effects  Deep Foundations Required  Closed During a Storm 80 of 143 P a g e | 7 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 2 Open Walkway 3. Walled Walkway This alternative is similar to the Open Walkway, but it includes walls to work as barriers preventing water from entering the walkway. This alternative is not preferable due to the following:  Higher Hydraulics Impact than Open Walkway o Scour o Potential Back Water Effects  Additional foundations required for the wall  Closed During a Storm Figure 3 ADA Crossing Under Exist Bridge 4. Tunnel The design team also considered a standard tunnel underneath Carlsbad Blvd for a crossing at this location. A tunnel typically requires a cover that is twice its diameter. To provide 9 ft overhead clearance, which is the minimum clearance requested by the City for a closed crossing, the tunnel will need to be about 30 ft below ground. Considering WSE discussed previously, a tunnel is not feasible for this location. 5. Cut and Cover Similar to the tunnel, this alternative would also be underneath Carlsbad Blvd however the trench excavated is much shallower as the earth cover can be 12 inches minimum. Precast reinforced concrete (PC/RC) box culvert is proposed for this alternative. The design team found this alternative to be the most feasible option for a crossing at this location considering design limitations discussed previously. 81 of 143 P a g e | 8 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 4 ADA Crossing Under Exist Road The results of the Wave Run-up study indicate higher water elevations as noted previously, which reduces the available vertical clearance under the existing Carlsbad Blvd Bridge. Therefore, alternatives 2 and 3 were eliminated. As a result, the cut and cover alternative was selected as the preferred structure type for this location. 4.0 Feasibility Study Results Proposed Structure The recommended alternative is a single cell precast reinforced concrete (PC/RC) box culvert crossing under Carlsbad Blvd, north of the existing Carlsbad Blvd Bridge. The proposed structure would be built using accelerated bridge construction (ABC) methods to minimize disruption to traffic and adjacent residents. The completed structure will be 92.5 feet long and 12 feet wide and 9 feet high, following the same skew of the existing Carlsbad Blvd Bridge. Based on Caltrans Standard Plans, the proposed PC/ RC Box Culvert will have 12-inch slabs and walls. The design assumes 2 feet of cover on top of the culvert. Two cast in place (CIP) wing walls will be constructed on both ends of the box culvert. On the west end of the culvert, at Tamarack State Beach, a 4 feet berm is proposed to keep water out of the structure. Additionally, a gate can be added to both ends of the culvert, so it can be closed if flooded. The gate could also serve as a barrier to prevent sand and dirt from entering the crossing. The box culvert is sloped at 1% from west to east to drain into a proposed 18-inch storm drain on the eastern end of the crossing. ADA Ramp at Trail In order to provide complete ADA access from the eastern side of Carlsbad Blvd to Tamarack State Beach on the west, an ADA ramp connecting the eastern sidewalk of Carlsbad Blvd to Agua Hedionda Trail would be provided. The ramp would be about 255-foot long and 8-feet wide. Cast-in-place retaining walls are proposed to frame the ramp with handrails on both sides of the ramp. 82 of 143 P a g e | 9 Trail Connectivity to Tamarack State Beach Feasibility Study ADA Connection to Lower Sea Wall On the western side of the box culvert crossing under Carlsbad Blvd, an ADA compliant concrete walkway will connect to the existing parking lot. The parking lot will be reconfigured to provide a 4-foot wide ADA path of travel along the western edge of the existing parking lot. The parking lot will be re-striped to accommodate the proposed ADA path of travel, while maintaining the existing number of parking stalls and minimum parking lot drive aisle widths. The ADA path of travel will connect to an accessible 5-foot wide concrete ramp. This ramp will connect to the modified Lower Sea Wall to provide a fully ADA compliant connection from the box culvert under Carlsbad Boulevard to the Lower Sea Wall and proposed ADA Beach Access ramp at Tamarack Avenue. The proposed modification to the Lower Sea Wall includes the removal of approximately 5-feet of the existing “return wall” in order to create a connection location for the proposed ramp. Constructability A specific construction staging and traffic control plan will be developed upon final design. Preliminary information indicates the road will need to be closed during construction to excavate a trench and then it can be covered with a temporary trench plate. Road closure will also be required to relocate existing utilities that are in conflict with the proposed structure. These activities can be accomplished as night or weekend work and it can be staged to minimize traffic impact. Geotechnical Based on preliminary review of existing conditions and the Geotechnical Investigation Report for the Tamarack Coastal Improvements Project prepared by AECOM on March 2018, 2 feet of over-excavation and recompaction may be required within the limits of the proposed box culvert. Since the proposed structure is entirely in the bluffs, putting it in formational soil (Terrace Deposits), liquefaction would not be an issue. Therefore, no ground improvements beyond the over- excavation and recompaction are warranted. Utilities There are multiple existing utilities in the project area that will be affected by the proposed crossing. Existing 4-inch HP Gas and electrical conduits for street lights can be relocated to be on top of the box culvert. A portion of a 12-inch ACP Water Line will be impacted by the proposed crossing, so it will need to be relocated underneath the proposed box culvert. Additionally, an existing 18-inch RCP Storm Drain runs along the proposed structure, so it will need to be relocated and reconnected to an existing headwall on the beach side. All this work will need to be coordinated and performed during road closures. Aesthetics For the box culvert crossing at Cold Water, it is proposed to extend the raised median on Carlsbad Blvd north, so it crosses the box culvert, in order to provide a glass light well through the median. Lighting would also be provided in the crossing. Additionally, new vegetation is proposed on the bluffs at Agua Hedionda Trail to replace existing vegetation that would be impacted by the proposed crossing and ramp. Figure 5 and Figure 6 displays the conceptual design renderings for the proposed cut-cover tunnel. Opinion of Probable Construction Costs The project team developed a planning level opinion of probable construction costs for the trail connection. The estimated cost, including design and CEQA clearance, was $3.0M for the trail connection. A breakdown of costs can be found in Appendix B. 83 of 143 P a g e | 10 Trail Connectivity to Tamarack State Beach Feasibility Study CEQA Clearance The project team completed an evaluation of environmental constraints to help transition into the next phase of the project. The biggest constraint are the existing biological resources that would be impacted by construction. However, these impacts can be mitigated. The Environmental Constraints Analysis Table can be found in Appendix C. 84 of 143 P a g e | 11 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 5 Cold Water Cut-Cover Tunnel Rendering 85 of 143 P a g e | 12 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 6 Cold Water Cut-Cover Tunnel 3-D Simulation 86 of 143 P a g e | 13 Trail Connectivity to Tamarack State Beach Feasibility Study Figure 6.A Tamarack State Beach Parking Access 87 of 143 P a g e | 14 Trail Connectivity to Tamarack State Beach Feasibility Study 5.0 Conclusion As described in this report, the City of Carlsbad Community Services – Parks & Recreation Department commissioned a feasibility study for a connection between the North Shore Agua Hedionda Lagoon Trail and Tamarack State Beach via pedestrian walkway, tunnel, or at grade crossing. After an engineering evaluation and analysis of different alternatives that took into consideration factors such as terrain, sea level rise, and constructability, the cut-cover tunnel was found to be the most feasible option to connect the North Shore Agua Hedionda Lagoon Trail and Tamarack State Beach. 88 of 143 P a g e | 15 Trail Connectivity to Tamarack State Beach Feasibility Study Appendix A Final Wave Runup Study 89 of 143 Wave Run-up Study City of Carlsbad ADA Beach and Lagoon Access Feasibility Study Prepared for Chen-Ryan and Associates 3900 Fifth Avenue, Suite 310 San Diego, CA 92103 GHD | 9370 Sky Park Ct, Suite 140, San Diego, CA 92123, USA 11186682 | December 14, 2018 (revised January 30, 2019) 90 of 143 Table of Contents 1. Introduction ................................................................................................................................... 1 2. Scope of Work .............................................................................................................................. 3 3. Existing Conditions & Coastal Setting .......................................................................................... 4 3.1 FEMA Mapping .................................................................................................................. 7 3.1.1 Effective Flood Insurance Rate Map ................................................................ 7 3.1.2 Preliminary Flood Insurance Rate Map: ........................................................... 8 3.2 U.S. Geological Survey Coastal Storm Observing System (CoSMoS 3.0) ....................... 9 3.3 SANDAG Beach Profile Data ........................................................................................... 12 4. Oceanographic Data .................................................................................................................. 15 4.1 Water Level ...................................................................................................................... 15 4.1.1 Tidal Datums ................................................................................................... 15 4.1.2 Tides ............................................................................................................... 16 4.1.3 Sea Level Anomaly ......................................................................................... 16 4.1.4 Non-Tidal Residuals ....................................................................................... 17 4.1.5 Sea Level Rise................................................................................................ 18 4.2 Wave Conditions .............................................................................................................. 19 4.3 Beach Profile Analysis ..................................................................................................... 20 5. Wave-Runup Results ................................................................................................................. 21 6. Alternative Vulnerability Analysis ............................................................................................... 25 6.1 At-grade Walkway ............................................................................................................ 25 6.2 Pedestrian Bridge ............................................................................................................ 25 6.3 Cut and Cover structure ................................................................................................... 26 7. Conclusions ................................................................................................................................ 27 8. References ................................................................................................................................. 28 91 of 143 Figure Index Figure 1. Pedestrian Bridge Concept (source: T.Y. Lin International) ................................................... 2 Figure 2. Cut and Cover Concept (source: T.Y. Lin International) ......................................................... 2 Figure 3. Project Location Map .............................................................................................................. 6 Figure 4. Project Map Showing Existing Coastal Structures and Topography (2011 SCC Lidar ft, NAVD88) ............................................................................................................................ 6 Figure 5. FEMA NFIP Effective Flood Map for the Study Area .............................................................. 8 Figure 6. FEMA NFIP Preliminary Flood Map for the Study Area .......................................................... 9 Figure 7. CoSMoS Sea Level Rise Hazards in with 0.5m of Sea Level Rise (M&N 2015) .................. 10 Figure 8. CoSMoS Sea Level Rise Hazards in with 2.0m of Sea Level Rise (M&N 2015) .................. 11 Figure 9. Tamarack Seasonal Beach Profile Change at CB-0830 from Spring 1996 to Fall 2017 (CFC 2017) ................................................................................................................................ 13 Figure 10. Tamarack Mean Sea Level Beach Width Change from 1997 to Present (CFC Profile CB- 0830). ............................................................................................................................... 14 Figure 11. Water Level and Wave Data Locations Near the Project Site. ........................................... 15 Figure 12. Non-Tidal Residual Hazard Curve for La Jolla.................................................................... 18 Figure 13. Significant Wave Height Return Periods for the Study Area ............................................... 20 Figure 14. Seasonal CB-0830 Profiles from 2010 to 2012 (left) and Mean/Standard Deviation Profile (right). .............................................................................................................................. 21 Figure 15. Wave Runup Hazard Curves for Project Site (ft NAVD88). ................................................ 23 Figure 16. 10-yr Return Period Runup Elevations during Existing Conditions (2018) and Future Condition (2068). ............................................................................................................. 24 Figure 17. 100-yr Return Period Runup Elevations during Existing Conditions (2018) and Future Condition (2068). ............................................................................................................. 25 Table Index Table 1. Tidal Datums from NOAA La Jolla Station 9410230. ............................................................. 16 Table 2. Astronomical Water Level Exceedance for La Jolla. .............................................................. 16 Table 3. Sea Level Anomaly Exceedance for La Jolla. ........................................................................ 17 Table 4. Non-Tidal Residual Return Period for La Jolla. ...................................................................... 17 Table 5. Sea Level Rise Trends for La Jolla ........................................................................................ 19 Table 6. Significant Wave Height Return Period for the Study Area (WIS 83105) .............................. 20 Table 7. Wave Runup Elevations for Project Site (ft, NAVD88). .......................................................... 23 92 of 143 1. Introduction Chen Ryan Associates, under contract to the City of Carlsbad (Carlsbad), is evaluating the feasibility of connecting the North Shore Agua Hedionda Trail to Tamarack State Beach through an ADA accessible pathway. Alternatives being considered to provide this connection are described below: 1. At-grade connecting walkway – An at-grade crosswalk on Carlsbad Boulevard with ramps and/or stairs to the beach. This concept has not be developed at the time of this study. 2. Pedestrian Bridge – An under-bridge pedestrian bridge / walkway under the Cold Water Inlet Bridge, adjacent to the northern bridge abutment, as shown in Figure 1. A 9’ vertical clearance is desired for the walkway. 3. Cut and Cover walkway – A cut and cover walkway under Carlsbad Boulevard, as shown in Figure 2. A 9’ vertical clearance is desired for the walkway and a three-foot cover thickness is assumed. Aesthetics, functionality, environmental impact and coastal vulnerability are all factors being considered in the evaluation of these potential options. GHD was contracted by Chen Ryan Associates to evaluate existing and potential future coastal hazards (i.e. flooding and inundation) that may impact the alternatives being considered in the feasibility study. The approach of this analysis was developed using the Sea Level Rise Policy Guidance developed by the California Coastal Commission (CCC) (August 2015) as updated by the recommendations of the Adopted Science Update in November 2018 (California Coastal Commission, 2018). 93 of 143 Figure 1. Pedestrian Bridge Concept (source: T.Y. Lin International) Figure 2. Cut and Cover Concept (source: T.Y. Lin International) 94 of 143 2. Scope of Work GHD was retained by Chen Ryan Associated to prepare a Wave Run-up Study to support the Carlsbad ADA Beach Access and Lagoon Feasibility Study Project for the City of Carlsbad. The scope of work for this study is summarized below: 1. Review Existing Information - Available information for the study area was reviewed to form an overview of the Project site from a coastal perspective. Data reviewed included the: City of Carlsbad Sea Level Rise Vulnerability Study, Coastal Storm Observing System data (CoSMoS 3.0), beach profile data (from SANDAG’s regional beach monitoring program) and FEMA data (effective and preliminary maps). 2. Prepare Wave Runup Study and Site-specific Vulnerability Assessment – The site’s vulnerability to coastal hazards (flooding and inundation) was analyzed in comparison to the alternatives being considered with a focus on the ability of the proposed alternatives to withstand extreme storm events in combination with tides and future predictions of sea level rise. Determined existing and future wave runup elevations during frequently occurring and extreme events (assumed 10-year and 100-year return period wave events within a 50-year time horizon, respectively) to aide in the alternative evaluation. Once the limits of the coastal hazards were established, vulnerabilities of the proposed alternatives were evaluated. The analysis quantitatively described the frequency of coastal hazard exposure and the specific alternative’s sensitivity to these hazards. 3. Project Meetings and Management – GHD will attend two project team meetings; assumed at the Project kick-off and Draft Wave Runup report phases. 95 of 143 3. Existing Conditions & Coastal Setting The study area spans the shoreline from Tamarack Avenue to the northern Cold Water jetty. The site consists of a coastal parking lot (i.e. Tamarack State Beach), which is fronted by a sandy beach and backed by Carlsbad Boulevard (Figure 3). Carlsbad Boulevard is positioned on a coastal bluff and is elevated from the coastal parking lot. Approximate elevations of key features in the study area (relative to NAVD88, ft) are as follows: • Tamarack State Beach Parking Lot: +12 to +15 (west to east) • Carlsbad Boulevard (in vicinity of stairs): +26 • Cold Water bridge soffit: +17 • Tamarack back beach: +12 Jurisdictionally, the City owns and operates the roadway and California State Parks owns and manages the parking lot and beach at Tamarack. The parking lot is currently subject to frequent overtopping and State Parks has placed rip-rap on the seaward edge to help protect the lot during these events. Wave overtopping of the parking lot was evident during a site visit on November 1, 2018 as overwashed sand and marine debris were present on the western side of the lot (Photos 1 through 4). A vertical seawall begins immediately north of the parking lot, which spans about 3,500 feet to the north where it terminates in the vicinity of Pine Avenue (Figure 4). The sandy beach at Tamarack is managed in that its width is controlled by regional and local beach nourishment activities. Regionally, beach widths have been impacted by two large scale beach nourishment efforts conducted by SANDAG in 2001 and 2012. These projects are known as the Regional Beach Sand Project I and II, respectively. These projects placed about 2.1 million and 1.5 million cubic yards of sand on San Diego beaches. Placement of sand at two beaches upcoast from Tamarack State Beach (i.e. North Carlsbad and Oceanside placement sites) have impacted beach width and shape at this beach over time. These upcoast placement sites received a total of 646,000 cy and 512,000 cy of sand in 2001 and 2012, respectively from these regional projects (CFC 2017). Locally, the Tamarack beach is directly affected by the placement of sand from Agua Hedionda Lagoon maintenance dredging activities. The program bypasses an average of 135,000 cy (during the period of 2001 to 2015) of sand from the flood shoal of the lagoon annually (CFC 2017). Dredged sand is placed at three beach sites each year as follows: 1) north of the cold water jetties within the study area, 2) south of the cold water jetties and 3) south of the warm water jetties. The direct placement of sand on this beach impacts width and shape. 96 of 143 Photo 1. Tamarack State Beach Parking Lot. Photo 2. Cold Water Jetty and bridge northern abutment. Photo 3. Rip rap shoreline protection fronting parking lot. Evidence of recent wave runup into the parking lot. Photo 4. Rip rap shoreline protection fronting parking lot. 97 of 143 Figure 3. Project Location Map Figure 4. Existing Coastal Structures and Topography (2011 SCC Lidar ft, NAVD88) 98 of 143 3.1 FEMA Mapping The Federal Emergency Management Administration (FEMA) maps national coastal hazards using water level and wave data in order to derive their Flood Insurance Rate Maps (FIRM). Although these maps do not include sea level rise, they do include wave induced water levels including runup. These products were reviewed for the Project Site to understand FEMA mapped coastal hazards in the study area. FEMA is in the process of updating the FIRM for southern California; thus, the effective and preliminary maps were reviewed. Differences between the effective and preliminary FIRM products suggest that the base flood elevation (BFE) in the study area will increase from 11 feet (NAVD88) to 20 ft (NAVD88) and will change zone designations from AE and VE. More details on the findings of these map reviews are below. 3.1.1 Effective Flood Insurance Rate Map The FEMA Effective FIRM for the Project site (Panel 06073C0763G revised 5/16/2012) was reviewed. According to the Effective FIRM, the Project site is located in the vicinity of FEMA zones: Zone VE (EL 11) and Zone AE (EL 11), as shown in Figure 5. These zones are defined below: Zone VE (EL 11) – Coastal High Hazard Area with a base flood elevation (BFE) of 11 feet (NAVD88). The zone includes anticipated wave heights at or exceeding 3 feet; however, allows construction when the structure is designed to accommodate anticipated wave forces and when the minimum building foundations are above the BFE. Zone AE (EL 11) – Areas subject to inundation by the 1-percent-annual-chance (or 100-year) flood event determined by hydraulic methods. The zone has a BFE of 11 feet (NAVD88). 99 of 143 Figure 5. FEMA NFIP Effective Flood Map for the Study Area (Modified from: FEMA.gov) 3.1.2 Preliminary Flood Insurance Rate Map: The FEMA Preliminary FIRM for the Project site (Panel 06073C0763H issued 2/3/2017) was reviewed. According to the Preliminary FIRM, the Project site is located in Zone VE (EL 20) and Zone AE (EL 8), as shown in Figure 6. These zones are defined below: Zone VE (EL 20) – Coastal High Hazard Area with a base flood elevation (BFE) of 20 feet (NAVD88). The zone includes anticipated wave heights at or exceeding 3 feet; however, allows construction when the structure is designed to accommodate anticipated wave forces and when the minimum building foundations are above the BFE. Zone AE (EL 8) – Areas subject to inundation by the 1-percent-annual-chance (or 100-year) flood event determined by detailed methods. The zone has a BFE of 8 feet (NAVD88). 100 of 143 Figure 6. FEMA NFIP Preliminary Flood Map for the Study Area (Modified from: FEMA.gov) 3.2 U.S. Geological Survey Coastal Storm Observing System (CoSMoS 3.0) Carlsbad’s exposure to future rates of sea level rise was outlined in the City of Carlsbad Sea Level Rise Vulnerability Assessment (Moffatt & Nichol & Revell Coastal, 2015). To assess future vulnerability at the community scale, preliminary results from the CoSMoS 3.0 model were coupled with future predictions of sea level rise. CoSMoS was developed for hindcast studies, operational applications and future climate scenarios to provide emergency responders and coastal planners with storm-hazards information that can be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings (Barnard et al., 2018). The modeling approach that has been developed by the U.S. Geological Survey (USGS) to allow detailed predictions of coastal flooding due to both future sea level rise and storms integrated with long-term coastal evolution (i.e., beach changes and cliff/bluff retreat) over large geographic areas (100s of kilometers). The 100-yr return period coastal hazards for year 2050 (0.5m or 1.65 ft of sea level rise) is shown in Figure 7. Coastal hazards in the study area with 2.0m of sea level rise is shown in Figure 8. CoSMoS results differ from those proposed by FEMA. The intent of CoSMoS was not to identify coastal hazards at the parcel scale but instead to identify hazards and vulnerabilities over large geographic regions. CoSMoS was also developed to predict potential future hazards resulting from sea level rise while FEMA maps coastal hazards based on an analysis of existing data. 101 of 143 Figure 7. CoSMoS Sea Level Rise Hazards with 0.5m of Sea Level Rise (M&N 2015) Project Extent 102 of 143 Figure 8. CoSMoS Sea Level Rise Hazards with 2.0m of Sea Level Rise (M&N 2015) Project Extent 103 of 143 3.3 SANDAG Beach Profile Data In 1996, SANDAG initiated the Regional Shoreline Monitoring Program (Monitoring Program), which measures the changes in beach width over time, documents the performance of sand replenishment projects, and helps to improve the design and effectiveness of beach fills. The Monitoring Program provided data for the design of the 2001 and 2012 Regional Beach Sand Projects (RBSP) and helped guide the selection of candidate beach sites. Although the monitoring requirements imposed as permit conditions of the 2001 RBSP ended in 2006, SANDAG has continued a modified monitoring program (SANDAG, 2017). Profile CB-0830 of the Monitoring Program is located within the Project site at the north end of the Tamarack State Beach Parking Lot. The location of the transect is shown in Figure 4. Profiles at this location have been measured seasonally (spring/fall) from 1996 to 2017 and are shown in Figure 9. Profile CB-0830 is an accretional beach profile developed in response to regional and local nourishment programs. Sediment transport within the littoral cell influences beach profiles on a regional scale as sediment is moved along the coast in response to the wave climate. The most recent nourishment used sediment courser than native sand that resulted in a steepening of the upper shoreface relative to historic conditions. Figure 10 shows the time history of the mean sea level contour since 1996. The data indicate that the growth of the profile started in 2012, reaching the maximum beach width in 2014. An accretional beach profile, with seasonal fluctuations in profile width, has occurred since 1997. 104 of 143 Figure 9. Tamarack Seasonal Beach Profile Change at CB-0830 from Spring 1996 to Fall 2017 (CFC 2017) 105 of 143 Figure 10. Tamarack Mean Sea Level Beach Width Change from 1997 to Present (CFC Profile CB-0830). 106 of 143 4. Oceanographic Data The approach for this Wave Run-up Study is to analyze current and potential future site conditions relative to wave run-up. These elements are discussed in this section. 4.1 Water Level Water level data for the Project Site were obtained from National Oceanic and Atmospheric Administration (NOAA) La Jolla gauge (Station 9410230). The station is located at (32° 52' N, 117° 15.4' W) and was established in 1924 (with an updated installation in 1988). The tide gauge location is shown in Figure 11. Water levels from this site are analyzed in this section. Figure 11. Water Level and Wave Data Locations near the Project Site. 4.1.1 Tidal Datums Tidal datums in La Jolla are applicable to the San Diego region open-ocean coastline. The tidal datums are summarized in Table 1. Elevations in this report are described relative to the NAVD88 tidal datum. 107 of 143 Table 1. Tidal Datums from NOAA La Jolla Station 9410230. Datum Abbreviation Elevation (ft NAVD88) Highest Astronomical Tide HAT 6.95 Mean Higher-High Water MHHW 5.13 Mean High Water MHW 4.41 Mean Tide Level MTL 2.56 Mean Sea Level MSL 2.54 Mean Diurnal Tide Level DTL 2.47 Mean Low Water MLW 0.71 Mean Lower-Low Water MLLW -0.19 Lowest Astronomical Tide LAT -2.07 North American Vertical Datum of 1988 NAVD88 0.00 Station Datum STND -4.56 4.1.2 Tides Tides in Carlsbad are semidiurnal in nature, which refers to two highs and two lows occurring per day. Astronomical water levels were isolated from the tidal record by regressing known tidal frequencies onto the tidal record. Astronomical water levels for the Project site are shown in Table 2. Table 2. Astronomical Water Level Exceedance for La Jolla. Exceedance (%) Water Level (ft) 1 3.40 2 3.09 5 2.58 10 2.06 25 1.08 4.1.3 Sea Level Anomaly A mean sea level anomaly reveals the regional extent of anomalous water levels in the coastal ocean, which can indicate unusual water temperatures, salinities, average monthly winds, atmospheric pressures, and/or coastal currents. The sea level anomaly occurs over periods of months and demonstrates the interconnectedness of the ocean with atmospheric systems. Sea level anomalies are typical along the U.S. Pacific Coast with climatic events such as the El Niño Southern Oscillation (ENSO) (NOAA, 2013). The sea level anomaly exceedance curve for La Jolla is shown in Table 3. 108 of 143 Table 3. Sea Level Anomaly Exceedance for La Jolla. Exceedance (%) Water Level (ft) 1 0.49 2 0.40 5 0.28 10 0.21 25 0.10 4.1.4 Non-Tidal Residuals Non-tidal residuals (NTR) consist of components of the recorded water level not linked to astronomical tide or seasonal water levels. NTRs include water level responses to regional effects such as storm surge and changes in atmospheric pressure and typically occur on the order of days. Storm surge is an abnormal rise of water over and above the predicted astronomical tide, typically generated by a storm, and is generally the result of wind-induced set up along a shoreline. Atmospheric pressure changes result in water column expansion or retraction due to low and high- pressure systems, respectively. Return period NTR events within the La Jolla tidal record were identified through a statistical analysis of the tide gauge record. Results are summarized in Table 4 and shown in Figure 12. The data indicate the 50- and 100-year NTR events are 1.18 feet and 1.29 feet, respectively. Table 4. Non-Tidal Residual Return Period for La Jolla. Return Period (yr) Water Level (ft) 5 0.88 10 0.96 25 1.08 50 1.18 100 1.29 109 of 143 Figure 12. Non-Tidal Residual Hazard Curve for La Jolla. 4.1.5 Sea Level Rise Sea level rise trends were taken from California Coastal Commission Sea Level Rise Policy Guidance, Table G-11 for the La Jolla tide gauge. The authors state that the table is adapted from the 2018 California Ocean Protection Council Sea Level Rise Guidance (Ocean Protection Council (OPC), 2018) to present only the three scenarios OPC recommends evaluating. While the OPC tables include low emissions scenarios, only high emissions scenarios, which represent RCP 8.5, are included in this study because global greenhouse gas emissions are currently tracking along this trajectory. The H++ projection is a single “worst-case” scenario and does not have an associated likelihood of occurrence. Projections are relative to a baseline year of 2000 (or more specifically, the average relative sea level over 1991-2009). Although all three SLR scenarios were assessed in the analysis, the Medium-High Risk Aversion projection is specifically discussed below. 110 of 143 Table 5. Sea Level Rise Trends for La Jolla Projected Sea Level Rise (in feet): La Jolla Probabilistic Projections (in feet) H++ Scenario (based on Kopp et al. (2014)) (Sweet et al., 2017) Year Low Risk Aversion Medium-High Risk Aversion Extreme Risk Aversion Limit of "likely range" 1-in-200 chance Single scenario (~17% probability SLR exceeds...) (0.5% probability SLR exceeds…) (no associated probability) 2000 0.0 0.0 0.0 2030 0.6 0.9 1.1 2040 0.9 1.3 1.8 2050 1.2 2.0 2.8 2060 1.6 2.7 3.9 2068 1.9 3.4 4.9 2070 2.0 3.6 5.2 2080 2.5 4.6 6.7 2090 3.0 5.7 8.3 2100 3.6 7.1 10.2 2110 3.7 7.5 12.0 2120 4.3 8.8 14.3 2130 4.9 10.2 16.6 2140 5.4 11.7 19.2 2150 6.1 13.3 22.0 (Adapted from: California Coastal Commission Sea Level Rise Policy Guidance, Table G-11) 4.2 Wave Conditions Water level data for the Project Site were obtained from United States Army Corps of Engineers (USACE) Wave Information Studies (WIS) Station 83105. The wave station location is shown in Figure 11. The objective of the WIS is to provide high-quality coastal wave hindcast model estimates, wave analyses products and decision tools nationwide (U.S. Army Corps of Engineers, 2010). Wave estimates were hindcast using high quality wind fields, ice fields where appropriate and the latest wave modeling technology. To satisfy the Corps requirement for risk-based designs, long records of continuous wave climatology data are required. Hindcast datasets provide hourly wave information for locations every few miles along the coast. Return period significant wave height events at the WIS station were identified through a statistical analysis of the tide gauge record. Results are summarized in Table 6 and shown in Figure 13. The data indicate the 50- and 100-year return period wave events are 19.8 feet and 21.3 feet, respectively. Note that a 10 year return period event has a 10% chance of occurring in any given year and that a 100-year event has a 1% chance of occurrence in a year. 111 of 143 Table 6. Significant Wave Height Return Period for the Study Area (WIS 83105) Return Period (yr) Sig. Wave Height (ft) 5 14.5 10 16.1 25 18.2 50 19.8 100 21.3 Figure 13. Significant Wave Height Return Periods for the Study Area 4.3 Beach Profile Analysis Beach profiles were used to characterize local beach conditions at the Project site. SANDAG profiles (CB-0830) from Spring 2010 to Fall 2012 were selected and averaged to form a representative profile. Although there are more recent profiles, the most recent profiles seem strongly influenced by RBSP II project that have steepened the shoreface and do not appear representative of natural beach conditions. Since wave runup results are influenced by beach slope (i.e. steeper beach slope results in higher runup elevation), choosing a different representative beach profile would change the results. 112 of 143 Figure 14. Seasonal CB-0830 Profiles from 2010 to 2012 (left) and Mean/Standard Deviation Profile (right). 5. Wave-Runup Results Probabilistic hazard analysis provides a means to incorporate natural uncertainties, model uncertainties and errors into the hazard assessment. Probabilistic hazard analysis was extended to oceanographic problems [see Geist & Parsons (2006) & Geist & Lynett (2014)] by adapting a long- standing probabilistic method for determining ground motion exceedance caused by earthquake known as probabilistic seismic hazard analysis (Cornell, 1968). Probabilistic hazard analysis is founded on the idea of separating input variable return periods (e.g. storm surge, significant wave height) from hazard recurrence periods. Using a Monte Carlo methodology, variables constrained by the prescribed probability density functions can be input to a given set of governing equations to generate realizations which define the hazard recurrence space. This methodology is ideal where the governing equations may be well known, but the independent variables of the input as well as the resisting design components may not be completely known. The process repeats hundreds or thousands of times to generate a statistical understanding of design parameters (e.g. still water level, runup elevation) which contains the uncertainty of the input parameters. Once the statistical parameters space is defined, the maximum envelope of all of these realizations is estimated which represents the best estimate of the design parameter hazard. This curve is what is known as the hazard curve. 113 of 143 For instance, for a given set of significant wave heights and water levels, it is possible that each parameter set can have the same recurrence period but that the individual components can have vastly difference individual recurrences. When coupled with a set of governing equations, the difference in the input parameters can result in a wide array of possible solutions which define the parameter space by recurrence period. Therefore, by defining the maximum envelope or hazard curve for a given set of significant wave heights and water levels, it is possible to directly estimate which solution defines the upper bound of the recurrence hazard. This upper bound is what is defined as the hazard curve. The run-up elevations (𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇) for the Project site were estimated using a Monte Carlo methodology where the water level is a summation of individual components. 𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇=𝜂𝜂𝑑𝑑𝑇𝑇𝑇𝑇𝑑𝑑𝑑𝑑+𝜂𝜂𝑇𝑇𝑡𝑡𝑑𝑑𝑡𝑡+𝜂𝜂𝑠𝑠𝑡𝑡𝑇𝑇𝑠𝑠𝑇𝑇𝑠𝑠𝑇𝑇𝑇𝑇+𝜂𝜂𝑁𝑁𝑇𝑇𝑁𝑁+𝜂𝜂𝑆𝑆𝑆𝑆𝑁𝑁+𝑅𝑅2 where 𝜂𝜂𝑑𝑑𝑇𝑇𝑇𝑇𝑑𝑑𝑑𝑑 is the data reference, 𝜂𝜂𝑇𝑇𝑡𝑡𝑑𝑑𝑡𝑡 is the tidal elevation, 𝜂𝜂𝑠𝑠𝑡𝑡𝑇𝑇𝑠𝑠𝑇𝑇𝑠𝑠𝑇𝑇𝑇𝑇 is the seasonal water level elevation, 𝜂𝜂𝑁𝑁𝑇𝑇𝑁𝑁 is the nontidal residual elevation, 𝜂𝜂𝑆𝑆𝑆𝑆𝑁𝑁 is the sea level rise elevation at a given time period and 𝑅𝑅2 is the run-up point reached or exceeded by only 2% of all waves. Wave constituents are input into the Stockdon, Holman, Howd, & Sallenger (2006) empirical run-up equation. This equation is commonly used to estimate run-up on sandy beaches along the western U.S. shorelines. The equation is defined as follows: 𝑅𝑅2 = 1.1 �0.35 𝛽𝛽𝑓𝑓(𝐻𝐻0𝐿𝐿0)1/2 +�𝐻𝐻0𝐿𝐿0�0.563𝛽𝛽𝑓𝑓2 + 0.004��1/22� Where, 𝐻𝐻0 is offshore significant wave height, 𝐿𝐿0 is offshore significant wavelength and 𝛽𝛽𝑓𝑓 is beach slope. The 𝑅𝑅2 run-up level is a common metric for quantifying the maximum elevation inundated during a storm event. Run-up elevations return periods for the Project site are given in Table 7 and shown in Figure 15. The 10- and 100-year return period events for the existing condition are 16.0 feet and 19.5 feet, respectively. The 10- and 100-year return period events increase to 19.4 feet and 22.9 feet, respectively under the year 2068 Medium-High Risk Aversion sea level rise scenario. Elevations are shown overlaid on an aerial image for 2018 and 2068 in Figure 16 and Figure 17, respectively. These results are comparable to the preliminary FIRM map elevations developed by FEMA. The migration of mean sea level landward with the various projections of sea level rise are also shown in these figures. 114 of 143 Table 7. Wave Runup Elevations for Project Site (ft, NAVD88). Return Period (yr) 2018 Low Risk Aversion 2068 Medium-High Risk Aversion Extreme Risk Aversion, H++ 10 16.0 17.9 19.4 20.9 100 19.5 21.4 22.9 24.4 Figure 15. Wave Runup Hazard Curves for Project Site (ft NAVD88). 115 of 143 Figure 16. 10-yr Return Period Runup Elevations during Existing Conditions (2018) and Future Condition (2068). 116 of 143 Figure 17. 100-yr Return Period Runup Elevations during Existing Conditions (2018) and Future Condition (2068). 6. Alternative Vulnerability Analysis 6.1 At-grade Walkway Although the at-grade crosswalk on Carlsbad Boulevard concept has not been fully developed, the elevation of the crossing on the roadway would be outside the reach of coastal hazards in the existing and year 2068 condition. However, ramps and/or stairs down to the beach would likely be within the limits of wave runup during extreme events. Thus, design of the ramps and/or stairs to the beach should consider the coastal hazards described in this report. 6.2 Pedestrian Bridge Specific elevations of this concept have yet to be developed. However, based on the vertical walkway clearance desired and the bridge’s soffit elevation, it is likely that the under-bridge pedestrian bridge / walkway would be subject to frequent inundation (daily wetting and drying) associated with tides in the existing and year 2068 condition. The walkway would also be subject to flooding as waves commonly propagate between the cold water jetties in the existing condition. Design of this concept should consider frequent wetting and drying and wave forces acting on the structure. 117 of 143 6.3 Cut and Cover Structure The vulnerability of the cut and cover walkway under Carlsbad Boulevard is at its connection to the Tamarack State Beach parking lot. Given the walkway’s design that includes a 9’ vertical clearance and three-foot cover thickness, the walkway enters the parking lot at an elevation of approximately +14’. Assuming this elevation, the walkway would be vulnerable to flooding during less than a 10- year return period wave event in the existing condition (without sea level rise). Under any sea level rise scenario (Low or Medium-High Risk Aversion) by year 2068, the frequency and severity of walkway flooding would increase. Flooding events would expose the walkway to salt water, sand and debris during peak periods of the tidal cycle and wave event. Therefore, exposure of the walkway to flooding would be relatively short in duration (few hours during a day) and episodic in nature. Adapting the walkway to accommodate impacts associated with flooding may include the following design concepts: • Incorporate drainage features within the walkway that allow water to discharge or percolate. • Protect the walkway’s western terminus from flood waters entering with a controlling structure, such as a cutoff wall or dike. • Improve shoreline protection at Tamarack State Beach parking lot to prohibit flooding. Concepts to prohibit flooding would require an engineered revetment of seawall on the seaward edge of the lot. Since the parking lot is owned by State Parks, coordination with the agency would be needed to progress this option. 118 of 143 7. Conclusions An analysis of existing and future coastal hazards was conducted to support Chen Ryan Associates in the preparation of a feasibility study for this Project. The analysis included maximum wave run-up during storm conditions in combination with potential future sea level rise (SLR). The approach of the analysis was developed in general conformance with the California Coastal Commission (CCC) SLR Policy guidance including recommendations within the Science Update released November 2018. The 10- and 100-year return period wave runup elevations in the existing condition are 16.0 feet and 19.5 feet, respectively. The 100-year runup result is comparable to that shown in the NFIP preliminary map elevations developed by FEMA. The 10- and 100-year return period events increase to 19.4 feet and 22.9 feet, respectively under the year 2068 Medium-High Risk Aversion sea level rise scenario. Based on a review of available information for the alternatives being considered in this feasibility study, we offer the below coastal hazard vulnerability findings and recommendations: • At-grade Walkway: This concept would not be exposed to coastal hazards in the existing or year 2068 condition. However, ramps and/or stairs down to the beach would likely be within the limits of wave runup during extreme events. Thus, design of the ramps and/or stairs to the beach should consider the coastal hazards described in this report. • Pedestrian Bridge: Although elevations of the walkway deck and underdeck were not available at the time of this analysis, the structure would likely be subject to frequent inundation (daily wetting and drying) associated with tides in the existing and year 2068 condition. The walkway would also be subject to flooding and wave forces acting on the structure as ocean waves commonly propagate between the cold water jetties. A more detailed analysis would be needed to understand the extent of wave impacts on this structure. It is recommended that the design of this concept consider frequent wetting and drying and wave forces acting on the structure. • Cut and Cover Walkway: The western terminus of the walkway would be vulnerable to flooding during a 100-year return period wave event without sea level rise. The walkway would be vulnerable to flooding during anything greater than a 10-year return period wave event with predictions for sea level rise by year 2068. This assumes that the walkway’s western terminus elevation is +14’ NAVD88. Incorporation of drainage controls within the walkway, installation of a water controlling structure fronting the terminus of the walkway, and protection of the parking lot from flooding with a coastal structure (such as a seawall) were presented as potential design options to lessen coastal vulnerabilities and accommodate sea level rise for this option. 119 of 143 8. References Barnard, P., Erikson, L., Foxgrover, A. C., Limber, P. W., O’Neill, A. C., & Vitousek, S. (2018). Coastal Storm Modeling System (CoSMoS) for Southern California, v3.0, Phase 2. U.S. Geological Survey. Retrieved from https://doi.org/10.5066/F7T151Q4 California Coastal Commission. (2018). California Coastal Commission Sea Level Rise Policy Guidance. State Of California—Natural Resources Agency. Cornell, C. A. (1968). Engineering seismic risk analysis. Bulletin of the Seismological Society of America, 58(5), 1583–1606. Coastal Frontiers Corporation. 2017. Shoreline Monitoring Program Annual Report. Prepared for SANDAG. Geist, E. L., & Lynett, P. J. (2014). Source processes for the probabilistic assessment of tsunami hazards. Oceanography, 27(2), 86–93. https://doi.org/10.5670/oceanog.2014.43 Geist, E. L., & Parsons, T. (2006). Probabilistic Analysis of Tsunami Hazards. Natural Hazards, 37(3), 277–314. https://doi.org/10.1007/s11069-005-4646-z Kopp, R. E., Horton, R. M., Little, C. M., Mitrovica, J. X., Oppenheimer, M., Rasmussen, D. J., … Tebaldi, C. (2014). Probabilistic 21st and 22nd century sea-level projections at a global network of tide-gauge sites. Earth’s Future, 2(8), 383–406. https://doi.org/10.1002/2014EF000239 Moffatt & Nichol & Revell Coastal. (2015). City of Carlsbad Sea Level Rise Vulnerability Assessment. City of Carlsbad. Ocean Protection Council (OPC). (2018). State of California Sea-Level Rise Guidance: 2018 Update. State of California. Retrieved from http://www.opc.ca.gov/ SANDAG. (2017). Regional Shoreline Monitoring Program. SANDAG. Retrieved from https://www.sandag.org/ Stockdon, H. F., Holman, R. A., Howd, P. A., & Sallenger, A. H. (2006). Empirical parameterization of setup, swash, and runup. Coastal Engineering, 53, 573–588. Sweet, W. V., Kopp, R. E., Weaver, C. P., Obeysekera, J., Horton, R. M., Thieler, E. R., & Zervas, C. (2017). Global and Regional Sea Level Rise Scenarios for the United States. NASA Goddard Space Flight Center, United States National Oceanic and Atmospheric Administration. Retrieved from https://ntrs.nasa.gov/ U.S. Army Corps of Engineers. (2010). Wave Information Studies Project Documentation. Coastal and Hydraulics Laboratory Engineer Research and Development Center. Retrieved from http://wis.usace.army.mil/ 120 of 143 P a g e | 16 Trail Connectivity to Tamarack State Beach Feasibility Study Appendix B Cost Estimate and Structures Estimate 121 of 143 CARLSBAD FEASIBILITY CONCEPTUAL COST ESTIMATE 04/25/2019 Description Measure Quantity Price Total Subtotals Site Civil Clearing and Grubbing LS 1 $7,740.00 $7,740 Roadway Excavation CY 227 $70.00 $15,890 Embankment CY 46 $120.00 $5,520 Remove Concrete (Curb and Gutter)LF 78 $10.00 $780 Remove Concrete (Sidewalk)SF 464 $10.00 $4,640 Remove Asphalt Concrete Pavement CY 83 $30.00 $2,480 Remove Concrete (Curb)CY 2 $290.00 $644 Class II Aggregate Base CY 82 $50.00 $4,100 Hot Mix Asphalt (TYPE A)TN 112 $120.00 $13,392 Minor Concrete (Sidewalk)CY 17 $700.00 $12,030 Minor Concrete (6" Curb & Gutter)CY 3 $550.00 $1,589 Minor Concrete (6" Curb)CY 5 $800.00 $4,296 Install 18" RCP Storm Drain LF 130 $200.00 $26,000 Install 48" RCP Storm Drain LF 135 $500.00 $67,500 Type A-6 Cleanout EA 1 $7,000.00 $7,000 Type B-1 Inlet EA 1 $6,200.00 $6,200 18" D-4 Headwall EA 1 $6,000.00 $6,000 18" Automatic Drainage Gate EA 2 $4,500.00 $9,000 Catch Basin - Type G EA 1 $3,900.00 $3,900 Concrete Pipe Collar EA 2 $4,000.00 $8,000 Remove RCP Storm Drain LF 104 $200.00 $20,800 Remove Inlet EA 1 $2,000.00 $2,000 Remove Drainage Structure EA 1 $4,000.00 $4,000 Relocate Street Light EA 2 $4,000.00 $8,000 Midwest Guardrail System LF 80 $80.00 $6,400 Fence LF 101 $30.00 $3,030 SWPPP LS 1 $10,000.00 $10,000 Construction Area Traffic Control LS 1 $50,000.00 $50,000 Civil Subtotal $310,931 Utilities Relocate 6" PVC Sewer Force Main LS 1 $65,000.00 $65,000 Relocate 12" CMLC Water LS 1 $100,000.00 $100,000 Relocate 4" HP Gas LS 1 $65,000.00 $65,000 Utility Subtotal $230,000 1 of 2122 of 143 CARLSBAD FEASIBILITY CONCEPTUAL COST ESTIMATE 04/25/2019 Description Measure Quantity Price Total Subtotals ADA Ramp Clearing and Grubbing LS 1 $23,712.92 $23,713 Roadway Excavation CY 139 $70.00 $9,730 Embankment CY 290 $120.00 $34,800 Minor Concrete (Sidewalk)CY 157 $700.00 $109,900 Concrete Ditch SF 252 $24.00 $6,048 Cast in Place - Retaining Wall SF 1,724 $150.00 $258,600 Handrail LF 610 $90.00 $54,900 Ramp Subtotal $497,691 Structures Precast Box Culvert LS 1 $500,000.00 $500,000 Structures Subtotal $500,000 Lighting Lighting LS 1 $100,000.00 $100,000 Structures Subtotal $100,000 Landscape Relocate Interpretive Signage EA 1 $175.00 $175 Revegetation Areas SF 3,500 $2.50 $8,750 Temporary Irrigation SF 3,500 $1.50 $5,250 Irrigation trenching/wiring (Asphalt removal and replacement included)Allowance 1 $2,500.00 $2,500 Utility Subtotal $16,675 Construction Total $1,655,297 30% Contingency $496,589 Construction Grand Total $2,151,886 DESIGN COST Environmental and PE.%7 CCE $151,000.00 Design - 30% Package %4 CCE $87,000.00 Design - 60% and Permits %5 CCE $108,000.00 Design - 90%, Final, Bid Support %5 CCE $108,000.00 Design Subtotal $454,000 Construction Management (20%)$430,377 COST TOTAL $3,036,300 2 of 2123 of 143 Carlsbad ADA Beach Access Feasibility StudyPreliminary Structures Cost EstimateD. Kasawdish2/20/20191 .ADA Beach Access at Cold WaterStructure Type: Cut and Cover- RC/ PC Box CulvertRamp Length=92.5 LF6 ftPC Box Length per OldcastleCost/ Box= 10,000$ No. Boxes= 16 Structure Cost=160,000$ Add'n costs= 200,000$ Excavation, backfill, wing walls plus non standard box for skylightTotal=360,000$ Add 25%ContingencyStructure Cost=360,000$ For Budget, Use $ 400,000Based on estimate provided by Oldcastle and input from TYLI CMCost already included in the total estimate under Structures124 of 143 P a g e | 17 Trail Connectivity to Tamarack State Beach Feasibility Study Appendix C Environmental Constraints Table 125 of 143 Carlsbad Trail Connectivity to Tamarack State Beach Feasibility Study – Environmental Constraints Analysis Table 1 Alternative Summary The preferred alternative for the Trail Connectivity to Tamarack State Beach project involves constructing a cut and cover tunnel beneath Carlsbad Boulevard and constructing ADA compliant ramps on both sides of the tunnel. The tunnel would be approximately 93-feet and the ramps would have a maximum incline of 7.9 percent. The tunnel/ramp system would connect to the existing North Shore Agua Hedionda Lagoon Trail and provide connectivity from the east side of Carlsbad Boulevard to the beach. Issue Area Existing Conditions/Assumptions Trail Connectivity to Tamarack State Beach Constraints Summary Aesthetics · Existing structures on the west side of Carlsbad Boulevard include a jetty armored with rock slope protection, and a parking lot with the open beach just west of these structures. On the east side of Carlsbad Boulevard, existing trails along with a small undisturbed hillside are below residential homes, which line the perimeter of the lagoon. · No designated scenic resources are located in the area. · Construction of the tunnel/ramp system would be primarily in a previously developed area or would coincide with existing trails. · Extension of the trail system, including signage, would be consistent with existing design. · Landscaping of native vegetation would be established adjacent to the proposed improvements. · Aesthetic impacts are not anticipated, as the design of this alternative would be similar to the existing developed areas adjacent to this site. · The portion of the ramp that would connect to eastward trails would be designed similarly to the existing trail. · This option would not interfere with views of the coastline. · The tunnel would not be highly visible to users as it is situated under an existing developed roadway/structure. Air Quality · It is assumed that no operational sources are associated with this option, therefore only construction impacts are evaluated. · No sensitive receptors are located in the vicinity of the proposed project. · Potential impacts due to construction would be temporary. Standard construction equipment would be used. · Air quality emissions associated with the proposed project include emissions from construction, including trenching under the roadway. However, operations associated with construction would minimize emissions through standard construction measures, storm water pollution prevention plan measures, and best management practices. · Construction would be temporary; applicable measures would be implemented as necessary to minimize emissions. Biological Resources · The majority of vegetation to the west and east of Carlsbad Boulevard is planted vegetation and/or bare ground or beach. The proposed tunnel would be connected to the existing State Parks parking lot west of Carlsbad Boulevard. East of Carlsbad Boulevard, the proposed ramp would impact the existing hillside, which mostly consists of sparse vegetation and existing trails. It should be noted that planted rare plant species may be present in the vegetation to the east of Carlsbad Boulevard; however, this habitat is not expected to be contiguous with existing habitat to the east within the larger Agua Hedionda Lagoon complex and a low number of species are expected in this footprint. · Wildlife species in the proposed project site are not anticipated due to the disturbed footprint underneath and adjacent to Carlsbad Boulevard. However, habitat near the proposed project has potential eastward connection with Agua Hedionda Lagoon. North of the project site is coastal bluff, to the west is the Pacific Ocean, and to the south is the lagoon inlet. · If feasible, project implementation would avoid the aquatic environment and potential jurisdictional resources to the south. · This area is not located within the City of Carlsbad’s Habitat Management Plan (HMP) and is not designated as a significant wildlife corridor (City of Carlsbad 2004). · Equipment staging during construction would most likely occur in existing developed or unvegetated areas (e.g., sewer lift station parking lot east of Carlsbad Boulevard, trails, State Parks parking lot). · Impacts to vegetation may occur with installation of the ramp on the east side of Carlsbad Boulevard (e.g., vegetation removal). · Revegetation of bare ground and the establishment of formal trails would occur after ground-disturbing activities in the proposed project footprint. · The proposed improvements have the potential to impact vegetation near the site. However, the majority of the proposed project footprint is sparsely vegetated or consists of planted vegetation that has successfully established at the site, which indicates that plant establishment would most likely be successful post-construction. To the extent practicable, the design of the ramp/tunnel system uses existing infrastructure and trails, which would minimize impacts to vegetation. Best management practices would be implemented to ensure plant establishment adjacent to the ramp on the east side of Carlsbad Boulevard. · The proposed project footprint does not function as a major terrestrial wildlife movement corridor. No impacts are anticipated to wildlife movement/corridors with implementation of this option. · Measures would be implemented to avoid and/or minimize potential impacts to rare plant and/or wildlife species if found (e.g., plant salvage, clearance surveys for birds, and vegetation removal outside of the breeding season, if applicable). · To the extent practicable, aquatic and jurisdictional resources would be avoided during construction of the proposed improvements. · Temporary impacts to vegetation may occur; however, the proposed project site would be planted east of Carlsbad 126 of 143 Carlsbad Trail Connectivity to Tamarack State Beach Feasibility Study – Environmental Constraints Analysis Table 2 Issue Area Existing Conditions/Assumptions Trail Connectivity to Tamarack State Beach Constraints Summary Boulevard, and vegetation would be reestablished in this area post-construction. Cultural/Tribal Cultural Resources · A previous records search was conducted in the vicinity of the proposed project for the Carlsbad Boulevard and Tamarack Avenue Improvement Project in 2017 and encompassed the proposed tunnel/ramp system footprint (AECOM 2018). The previous records search indicated 20 studies have been conducted, four cultural resources were previously recorded, and one cultural resource was identified during a pedestrian survey, all within a 0.5 mile vicinity of the proposed project. After consulting with the Native American Heritage Council, it was determined that no Native American places or sites were on file in the vicinity of the proposed project site. Two prehistoric sites were recorded within 1,500 feet of the proposed project, one of which consisted of a short-term camp with shell midden and cobble base artifacts, while the other site had primarily shell and lithic scatter (AECOM 2018). The proposed project is not anticipated to impact these sites as they are located outside of the direct project footprint. · The proposed project would be located on previously undisturbed areas east of and under Carlsbad Boulevard. Potential for impacts could occur if a previously unknown resource was discovered during ground-disturbing activities. · Standard surveys, analysis, and mitigation measures (e.g., consulting a qualified archaeologist and a Native American representative, if applicable) would be implemented prior to and during construction, as required. Geotechnical/Geology · There are no active faults identified through Carlsbad, and the California Geologic Survey does not include Carlsbad on list of cities affected by the Alquist-Priolo Earthquake Fault Zones. However, Carlsbad is in a seismically active region and is subject to ground-shaking during an earthquake. · Geotechnical stability analyses were performed, indicating that the coastal bluffs in the project area currently have adequate factors of safety against deep instability and would not be located on an unstable geologic unit or on expansive soils (AECOM 2016). · As stated in the General Plan, the city of Carlsbad is located in the coastal portion of the Peninsular Ranges Geomorphic Province; a region characterized by northwest-trending structural blocks and intervening fault zones (City of Carlsbad 2015a). The proposed project areas consist of fill material and terrace deposits where the base of the bluffs is characterized by the Santiago Formation and relatively resistant sandstone forms the lower portion of the bluff (AECOM 2016). Pleistocene terrace deposits compose the upper portion of the bluff, above an elevation of approximately 8 to 12 feet above mean sea level (AECOM 2016). · The majority of the proposed project would be constructed on a previously developed site and have generally the same footprint as the existing trail system. However, potential impacts could occur associated with the soil removal and tunneling required to construct the tunnel. · Although loss of topsoil from project implementation is not anticipated to be substantial, measures would be adopted in order to minimize the potential impacts to topsoil with implementation (e.g., erosion control and revegetation/planting plan, City review of site grading plan to ensure compliance with code requirements). · The proposed project would adhere to all applicable building and seismic codes and regulations, and would therefore not expose people or structures to potential substantial adverse effects, including risk of loss, injury, or death due to severe ground shaking. · Due to the nature of the site as described under existing conditions, impacts related to increased slope instability, landsides, or other adverse seismic-induced geologic hazards are not anticipated. · Impacts to unique geologic or physical features are not anticipated with construction of the proposed improvements. Greenhouse Gas Emissions · It is assumed that no operational sources are associated with the proposed improvements, therefore only construction impacts are evaluated. · The City of Carlsbad adopted a Climate Action Plan (CAP) that outlines actions that the city will undertake to achieve its proportional share of the state Greenhouse gas (GHG) emissions reductions. The CAP is a plan for the reduction of GHG emissions in accordance with California Environmental Quality Act (CEQA) Guidelines Section 15183.5. Pursuant to CEQA · Standard construction equipment would be used and standard emissions controls would be implemented. · The proposed project is expected to be in compliance with the Carlsbad CAP and would not emit at or above the CAP screening threshold of 900 metric tons of CO2 equivalent, as outlined in the CAP Consistency Checklist. Additionally, the project’s incremental contribution to a cumulative GHG emissions effect would not be considered cumulatively considerable, because it would comply with the requirements of the CAP. 127 of 143 Carlsbad Trail Connectivity to Tamarack State Beach Feasibility Study – Environmental Constraints Analysis Table 3 Issue Area Existing Conditions/Assumptions Trail Connectivity to Tamarack State Beach Constraints Summary Guidelines Sections 15064(h)(3), 15130(d), and 15183(b), a project’s incremental contribution to a cumulative GHG emissions effect may be determined not to be cumulatively considerable if it complies with the requirements of the CAP. Land Use · The proposed project is surrounded by residential development to the northeast, the inlet of Agua Hedionda to the south, and the Pacific Ocean to the west. · The proposed project is in the coastal zone and subject to regulations per the California Coastal Act. · The proposed project footprint extends to an existing California State Parks parking lot and is located at Tamarack State Beach, which is under State Parks jurisdiction. · The proposed project would comply with applicable land use policies and guidelines. · The proposed project would conform to applicable land use policies and guidelines (e.g. Coastal Act) and appropriate resource agencies would be involved during the permitting process (i.e. California Coastal Commission, California State Parks). · The proposed tunnel/ramp system would establish trail connectivity from the North Shore Agua Hedionda Lagoon Trail to Tamarack State Beach. The proposed project would not only enhance east to west connectivity but would also establish ADA compliant ramps at this access location. The proposed improvements would be consistent with existing land use and recreation for the area. Noise · It is assumed that no operational sources are associated with this option, therefore only construction impacts are evaluated. · The closest noise sensitive receptors to the proposed project are residential structures 50 feet from the nearest construction boundary. · Given the open space and recreational nature of the proposed project site, the public using the beach could be considered a sensitive noise receptor during construction. · Carlsbad Boulevard may be closed temporarily to complete construction of the proposed project. It is anticipated this work would be completed at night to avoid peak commute and recreation times during the day. · Noise impacts associated with construction would be temporary, and standard construction equipment would be used. · During construction, noise minimization measures would be implemented and the project would follow the local noise ordinance as detailed in Chapter 8.48, Section 8.48.010, Noise of the City of Carlsbad Municipal Code to the extent possible. If construction work is performed at night to avoid peak commute and recreation times, an exception from the City of Carlsbad would be obtained to complete this work per Section 4.48.020 of the municipal code. · While the public using the beach during construction hours may experience higher noise levels anticipated with construction, other portions of the beach where temporary construction noise could be avoided will remain open for use. Residents adjacent to the proposed project area may experience construction noise at night; however, this work would be temporary and limited to short durations. Sound attenuation structures may be implemented to reduce noise as feasible. Recreation · The North Shore Agua Hedionda Lagoon Trail is located east of the proposed project footprint. · There are multiple existing access points along this portion of coastline, none of which are currently ADA compliant. Recreational opportunities exist on both sides of Carlsbad Boulevard without connecting access, currently, due to the roadway. · Construction would temporarily interrupt use at the western end of the existing trail system within the lagoon (e.g. the existing steep dirt path on the east side of Carlsbad Boulevard may be closed temporarily during construction). The remainder of the trail system east of the proposed project site would remain open during construction for use. · Currently, there is no east-to-west access across Carlsbad Boulevard; the only option is to travel a substantial distance north of the site to cross at the crosswalk at the intersection of Tamarack Avenue and Carlsbad Boulevard. A portion of the State Parks parking lot may be temporarily unavailable during construction including the existing staircase and the end of the trail system to the east would be · Recreation and public access would be temporarily interrupted during construction. Portions of the State Parks parking lot may be temporarily closed to stage equipment; however, a portion of the parking lot would be left open for recreational users. If feasible, proposed project work would be conducted outside of the busy summer season. · Post-construction, recreation and access would be enhanced via ADA compliant ramps with access beneath Carlsbad Boulevard, connecting trails and the beach, as well as establishing direct coastal pedestrian access from residential areas located east along the perimeter of the lagoon. 128 of 143 Carlsbad Trail Connectivity to Tamarack State Beach Feasibility Study – Environmental Constraints Analysis Table 4 Issue Area Existing Conditions/Assumptions Trail Connectivity to Tamarack State Beach Constraints Summary temporarily closed, but other access points along the beach and parking lots would remain open. Sea Level Rise /Storm Damage Vulnerability · The proposed improvements are subject to influences from sea level rise and increased wave action from more extreme storm events. The proposed project’s vulnerability to coastal hazards, such as flooding and inundation, were evaluated assuming 10- year and 100-year return period wave events over 50 years (GHD 2019). The point of vulnerability would be at the connection between the tunnel and the existing State Parks parking lot, which would be constructed at an elevation of approximately +14’ NAVD88, making the western part of the structure vulnerable during: · 1) a 100-year return period wave event without sea level rise, and; · 2) anything greater than a 10-year return period wave event with predictions for sea level rise by year 2068 (GHD 2019). · To the extent practicable, structures have been designed to provide resilience to coastal hazards, such as flooding and inundation, with the consideration of sea level rise in 50 years. · Due to the vulnerability of the connection point between the tunnel/ramp system and the existing parking lot, infrastructure may be subject to flooding events and/or impacts from large storm events most likely during the winter months. To minimize potential impacts from sea level rise, the City would monitor conditions of the access point and would use gates to close the tunnel if necessary under extreme events when flooding may occur. Closing the tunnel would minimize risk to the public using this access route. Closures would be short in duration and episodic, as flooding events would impact the tunnel during peak periods of the tidal cycle and wave event(s) (GHD 2019). Transportation/Traffic · It is assumed that no operational sources are associated with this option, therefore only construction impacts are evaluated. · Increased traffic to the site due to improved access is assumed to be minimal and most likely by existing users or residents using this improved route to access the beach, because the proposed project would create an ADA compliant ramp and safer/more direct pedestrian access. · Carlsbad Boulevard may be closed temporarily to complete construction of the proposed project. It is anticipated this work would be completed at night to avoid peak commute and recreation times during the day. · Traffic may be temporarily interrupted during construction. · Measures would be implemented during construction to avoid and/or minimize temporary traffic impacts (e.g., timing of project work, traffic control plan). Temporary closures to Carlsbad Boulevard are not anticipated to increase traffic, as they are designed to avoid the busiest times of the day. References AECOM 2016 Geotechnical Investigations Carlsbad Boulevard and Tamarack Avenue Pedestrian Improvements Project. 2018 Cultural Resources Phase I Survey Report for the Carlsbad Boulevard and Tamarack Avenue Improvement Project. City of Carlsbad 2004 Habitat Management Plan for the Natural Communities in the City of Carlsbad. Available at:http://www.carlsbadca.gov/civicax/filebank/blobdload.aspx?BlobID=27193. Accessed August 2016. 2015a General Plan. Available at:http://www.carlsbadca.gov/services/depts/planning/general.asp. Accessed July 2019. 2015b General Plan and Climate Action Plan Final Environmental Impact Report. Available at:http://www.carlsbadca.gov/civicax/filebank/blobdload.aspx?BlobID=28464. Accessed August 2016. GHD 2019 Wave Run-up Study, City of Carlsbad ADA Beach and Lagoon Access Feasibility Study. 129 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California SDG Project Number: 18-106 Date: January 23, 2020 Sheet 1 of 11 SHEET 1 TITLE SHEET SHEET 2 KEY MAP SHEET 3 PINE AVENUE SHEET 4 PHOTO SIMULATION - PINE AVENUE SHEET 5 TAMARACK AVENUE SHEET 6 PHOTO SIMULATION - TAMARACK AVENUE SHEET 7 TAMARACK PARKING ACCESS SHEET 8 COLD WATER TUNNEL SHEET 9 PHOTO SIMULATION - COLD WATER TUNNEL SHEET 10 DESIGN CHARACTER SHEET 11 PLANT MATERIAL 130 of 143 Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. PINE AVENUE TAMARACK STATE BEACH COLD WATER TUNNEL CARLSBAD BLVD.TAMARACK AVE.PINE ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Key Map NTS SDG Project Number: 18-106 Date: January 23, 2020 C C A A B B Sheet 2 of 11 131 of 143 Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : +42 +40.96 +39.01 +36.64 +34.25 +31.80 +29.47 +27.30 +25.07 +22.83 +18.06 +18.00 +20.61 (25) (35) (30) (40) (45) (20) 7 2 10 1 12 2 8 (35) (25) 9 11 7 4 6 5 3 1.5%7.5% Ma x Project Number: 18-106 Date: January 13, 2020 13 7 CARLSBAD BLVD.PINE AVE. CARLSB A D B L V D . ACCE S S R O A D EXIS T I N G M A I N T E N A N C E ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Pine Avenue Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. KEY PROPOSED 8’-0” RAMP WITH HANDRAILING 2% MAX. LANDINGS; TYPICAL PROPOSED PLANTING AREA; TYPICAL START OF ELEVATED ACCESSIBLE PATH ON STRUCTURAL COLUMNS END OF ELEVATED ACCESSIBLE PATH ON STRUCTURAL COLUMNS. PATH CONTINUES AT GRADE TO THE SOUTH EXISTING ADA ACCESSIBLE PARKING EXISTING BLUFF & TRAILS TO REMAIN; REPAIR AS NEEDED EXISTING STORM DRAIN PROPOSED LOCATION FOR RELOCATED SHOWER EXISTING SIDEWALK EXISTING RIP RAP EXISTING RESTROOM EXISTING SHOWER TO BE RELOCATED EXISTING CONDITIONS PROPOSED ACCESS RAMP SDG Project Number: 18-106 Date: January 23, 2020 1 2 3 4 5 6 7 8 9 10 11 12 13 Sheet 3 of 11 132 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Photo Simulation Pine Avenue Access SDG Project Number: 18-106 Date: January 23, 2020 Sheet 4 of 11 133 of 143 Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. PARKI N G L O T D R I V E W A Y ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Tamarack Beach Access KEY PROPOSED 8’-0” WIDE CONCRETE RAMP WITH HANDRAILING PROPOSED 8’ ELEVATED WOOD RAMP ON STRUCTURAL COLUMNS PROPOSED STAIRCASE PROPOSED PLANTING AREA; TYPICAL PROPOSED RETAINING WALL PROPOSED ACCESSIBLE PATH TO PARKING LOT EXISTING SEAWALL EXISTING RETAINING WALL EXISTING PLANTING AREA EXISTING GUARDRAILING RELOCATE EXISTING PICNIC TABLE RELOCATE EXISTING TRASH RECEPTACLES EXISTING PICNIC TABLE EXISTING SHOWERS AND PLAZA EXISTING FENCE EXISTING PAVING EXISTING LIFEGUARD TOWER EXISTING AC SIDEWALK EXISTING CONDITIONS EXISTING CONDITIONS EXISTING CONDITIONS PROPOSED ACCESS RAMP SDG Project Number: 18-106 Date: January 23, 2020 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Sheet 5 of 11 134 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Photo Simulation Tamarack Beach Access SDG Project Number: 18-106 Date: January 23, 2020 Sheet 6 of 11 135 of 143 6 5 2 1 4 3 7 CARLSBAD BOULEVARD SEQUOIA AVENUE +16.50 PROPOSED ACCESSIBLE PATH TO COLD WATER TUNNEL TAMARACK STATE BEACH PROPOSED ACCESSIBLE PATH TO CARLSBAD BOULEVARD +13.50 4.5% Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : CARLSBAD BEACH AND LAGOON CARLSBAD, CA Project Number: 18-106 Date: October 1, 2019 TAMARACK PARKING CONCEPT(20)(25)(30)(35)(15)(30)(15)(15)(15)Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Tamarack Parking Access KEY DEMO 5’-0” OF EXISTING SEA WALL EXISTING CURB TO REMAIN RESTRIPE EXISTING PARKING STALLS EXISTING SEA WALL PROPOSED 5’-0” CONCRETE WALKWAY PROPOSED ACCESSIBLE STRIPING EXISTING PARKING STRIPING TO REMAIN EXISTING SAND TO BE REMOVED AT NEW WALKWAY PROPOSED PARKING PATH SDG Project Number: 18-106 Date: January 23, 2020 1 2 3 4 5 6 7 8 Sheet 7 of 11 136 of 143 CARLSBAD BLVD . Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 13 7 11 10 3 6 12 +37 FS +33.95 FS +29.03 FS +26.56 FS +24.09 FS +21.62 FS +24 TW +24 TW +21.22 TW +19.15 FS +19 FS +18.7 FS +31.43 FS +35.85 FS +39.6 FS +39 FS (35) (35) (30) (25)(25)(30)(20)(30) (25) (20) +32 7.5% ELEVATED RAMP ENDS ELEVATED RAMP BEGINS Project Number: 18-106 Date: July 18, 2019 TAMARACK STATE BEACH EXISTING BLUFF TO REMAIN EXISTING TURF TO REMAIN 1 4 814 15 18 2 9 5 EXISTING PARKING LOT CARLSBAD BLVD. 17 16 EX. RESTROOM TAMARACK AVE. ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Cold Water Tunnel KEY PROPOSED PLANTING AREA; TYPICAL EXISTING AGUA HEDIONDA TRAIL - REPAIR AS NEEDED EXISTING RIP RAP LIMITS OF PROPOSED BOX CULVERT UNDER ROAD PROPOSED SKYLIGHT OPENING IN MEDIAN PROPOSED 8’-0” INTEGRAL COLOR CONCRETE ADA RAMP PROPOSED RETAINING WALLS & HANDRAILS PROPOSED 18” RCP STORM DRAIN PROPOSED CONCRETE “V” GUTTER EXISTING BRIDGE EXISTING STAIRCASE Project Number: 18-106 Date: March 19, 2019 Tamarack Ramp Carlsbad Beach and Lagoon Carlsbad, CA 0 10 20 40 1" = 20'-0"SCALE : 25 TW 18 TW + 14 FS + 14 FS+ 15 FS + 17.34 + 16.12 + 19.30 FS + 22.67 + 23.77 FS + 25.54 FS + 28 FS EX. BLDG. +21 FS242526272814 15 16 171516171417 TAMARACK STATE BEACH 5 7 1 3 1 4 3 1 6 11 1 76 10 EXISTING PARKING LOT CARLSBAD BLVD. 2 8 7 1 9 45 50 40 35 30 25 20 10 15 Project Number: 18-106 Date: July 18, 2019 EXISTING CONDITIONS EXISTING CONDITIONS EXISTING CONDITIONS EXISTING CONDITIONS PROPOSED ACCESS RAMP SDG Project Number: 18-106 Date: January 23, 2020 9 10 11 1 2 3 4 5 6 7 8 Sheet 8 of 11 137 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Photo Simulation Cold Water Tunnel Access SDG Project Number: 18-106 Date: January 23, 2020 Sheet 9 of 11 138 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Design Character PROPOSED ELEVATED CONCRETE PLANK SURFACE WITH GUARDRAILING CHARACTER PROPOSED STRUCTURAL COLUMN CHARACTER PROPOSED CONCRETE PLANK CHARACTER PROPOSED WALL LIGHTING CHARACTER PROPOSED LIGHTING INTEGRATED WITH HANDRAIL PROPOSED HANDRAIL CHARACTER PROPOSED STAIR RAILINGPROPOSED STAIR RAILINGPROPOSED RETAINING WALL TEXTURE SDG Project Number: 18-106 Date: January 23, 2020 Sheet 10 of 11 139 of 143 ADA BEACH & TRAIL CONNECTIVITY Feasibility Study Carlsbad, California Plant Material DWARF COYOTE BUSH Baccharis p. ‘Pigeon Point’ ARTEMISIA CALIFORNICA California Sagebrush COASTAL AGAVE Agave shawii ISLAND SHRUB MALLOW Lavatera assurgentiflora CHALK LIVEFOREVER Dudleya pulverulenta WILD LILAC Ceanothus maritimus COASTAL ENCELIA Encelia californica SEASIDE DAISY Erigeron g. ‘Wayne Roderick’ MANZANITA Arctostaphyllos x ‘Howard McMinn’ BEACH STRAWBERRY Fragaria chiloensis SEA DAHLIA Coreopsis maritima SANTA CRUZ ISLAND BUCKWHEAT Eriogonum arborescens RED BUCKWHEAT Eriogonum grande rubescens COASTAL GUM PLANT Grindelia stricta ISLAND SNAPDRAGON Galvezia speciosa SDG Project Number: 18-106 Date: January 23, 2020 Sheet 11 of 11 140 of 143