HomeMy WebLinkAbout2020-02-03; Traffic and Mobility Commission; ; AMERICAN WITH DISABILITIES ACT BEACH ACCESS FEASIBILITY STUDYItem 3
Meeting Date: Feb. 3, 2020
To: Traffic and Mobility Commission
Staff Contact: Nathan Schmidt, Transportation Planning and Mobility Manager
Nathan.Schmidt@carlsbadca.gov, 760-602-2734
Subject: American with Disabilities Act Beach Access Feasibility Study and
Trail Connectivity to Tamarack State Beach Feasibility Study
Recommended Action
The Traffic and Mobility Commission support staff’s recommendation to City Council to approve
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 evaluates
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
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
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.
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.
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 the ADA access ramps at Pine Avenue and Tamarack Beach, 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 cut and cover tunnel option as identified in 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 is scheduled to present like reports regarding the feasibility studies to the Beach
Preservation Commission on Feb. 4, 2020, the Parks & Recreation Commission on Feb. 24,
2020, and the City Council on Mar. 17, 2020. Staff will 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
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
August 2019
ADA Beach Access Feasibility Study
Final Report
Exhibit 1
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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
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Carlsbad ADA Beach Access
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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.
Exhibit 1
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Figure 1 – Project Study Area
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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.
Exhibit 1
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Carlsbad ADA Beach Access
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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
Exhibit 1
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Carlsbad ADA Beach Access
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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.
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Carlsbad ADA Beach Access
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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.
Exhibit 1
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Figure 2 – Habitat Value Assessment
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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.
Exhibit 1
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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).
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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.
Exhibit 1
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Carlsbad ADA Beach Access
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• 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.
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Figure 3 – North of Pine Avenue Ramp
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Figure 4 – North of Pine Avenue Ramp – Photosimulation
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Figure 5 – Tamarack Avenue Restroom Ramp
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Figure 6 – Tamarack Avenue Restroom Ramp – Photosimulation
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Figure 7 – Conceptual Design Character
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Figure 8 – Proposed Plant Materials
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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.
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Appendix A
Pedestrian Activity Analysis
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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
Exhibit 1
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 15
Exhibit 1
% 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 15
Exhibit 1
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 13
Exhibit 1
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 13
Exhibit 1
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 13
Exhibit 1
% 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 13
Exhibit 1
P a g e | 21
Carlsbad ADA Beach Access
Feasibility Study
Appendix B
Vegetation Constraints Memorandum
Exhibit 1
\ 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
Exhibit 1
Subject: Vegetation Constraints Review for ADA Accessibility
December 20, 2018
Page 2
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
Exhibit 1
P a g e | 22
Carlsbad ADA Beach Access
Feasibility Study
Appendix C
Existing Conditions Analysis
Exhibit 1
Carlsbad ADA Beach and Lagoon Access Feasibility StudyExhibit 1
Carlsbad ADA Beach and Lagoon Access Feasibility StudyExhibit 1
Carlsbad ADA Beach and Lagoon Access Feasibility StudyExhibit 1
Carlsbad ADA Beach and Lagoon Access Feasibility StudyExhibit 1
Carlsbad ADA Beach and Lagoon Access Feasibility StudyExhibit 1
P a g e | 23
Carlsbad ADA Beach Access
Feasibility Study
Appendix D
Pine Avenue and Tamarack Avenue Ramp Options
Exhibit 1
Exhibit 1
Exhibit 1
Exhibit 1
Exhibit 1
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)
Exhibit 1
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)
Exhibit 1
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)
Exhibit 1
P a g e | 24
Carlsbad ADA Beach Access
Feasibility Study
Appendix E
Pine Avenue and Tamarack Avenue Ramps
Exhibit 1
Exhibit 1
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P a g e | 25
Carlsbad ADA Beach Access
Feasibility Study
Appendix F
OPCC and Structures Estimate
Exhibit 1
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
$300,000.00
ADA Beach Access
from Carlsbad
Structural
Exhibit 1
Carlsbad ADA Beach Access Feasibility StudyPreliminary Structures Cost EstimateD. Kasawdish2/20/20191. ADA Beach Access from Carlsbad BoulevardStructure Type: Raised ramp supported on pile extension at each landing.Ramp Length476ftRamp Width10ftAs requested by City during February PDT meetingRamp Area=4,760 SFCost/ SF= 325$ 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.Exhibit 1
P a g e | 26
Carlsbad ADA Beach Access
Feasibility Study
Appendix G
Environmental Constraints Table
Exhibit 1
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.
Exhibit 1
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
Exhibit 1
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,
Exhibit 1
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
Exhibit 1
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.
Exhibit 1
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
Exhibit 2
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
Exhibit 2
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.
Exhibit 2
P a g e | 3
Trail Connectivity to Tamarack State Beach
Feasibility Study
Figure 1 Project Study Area
Location of
proposed crossing
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
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
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
P a g e | 11
Trail Connectivity to Tamarack State Beach
Feasibility Study
Figure 5 Cold Water Cut-Cover Tunnel Rendering
Exhibit 2
P a g e | 12
Trail Connectivity to Tamarack State Beach
Feasibility Study
Figure 6 Cold Water Cut-Cover Tunnel 3-D Simulation
Exhibit 2
P a g e | 13
Trail Connectivity to Tamarack State Beach
Feasibility Study
Figure 6.A Tamarack State Beach Parking Access
Exhibit 2
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.
Exhibit 2
P a g e | 15
Trail Connectivity to Tamarack State Beach
Feasibility Study
Appendix A
Final Wave Runup Study
Exhibit 2
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)
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page i
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
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page ii
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
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 1
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).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 2
Figure 1. Pedestrian Bridge Concept (source: T.Y. Lin International)
Figure 2. Cut and Cover Concept (source: T.Y. Lin International)
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 3
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 4
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 5
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 6
Figure 3. Project Location Map
Figure 4. Existing Coastal Structures and Topography (2011 SCC Lidar ft, NAVD88)
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 7
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).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 8
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).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 9
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 10
Figure 7. CoSMoS Sea Level Rise Hazards with 0.5m of Sea Level Rise (M&N 2015)
Project Extent
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 11
Figure 8. CoSMoS Sea Level Rise Hazards with 2.0m of Sea Level Rise (M&N 2015)
Project Extent
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 12
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 13
Figure 9. Tamarack Seasonal Beach Profile Change at CB-0830 from Spring 1996 to Fall
2017 (CFC 2017)
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 14
Figure 10. Tamarack Mean Sea Level Beach Width Change from 1997 to Present (CFC Profile
CB-0830).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 15
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 16
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 17
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
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 18
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 19
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 20
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 21
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 22
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 23
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).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 24
Figure 16. 10-yr Return Period Runup Elevations during Existing Conditions (2018) and
Future Condition (2068).
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 25
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 26
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 27
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.
Exhibit 2
GHD | Wave Run-up Study – ADA Beach Access and Lagoon Access Feasibility Study Project | 11186682 | Page 28
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/
Exhibit 2
P a g e | 16
Trail Connectivity to Tamarack State Beach
Feasibility Study
Appendix B
Cost Estimate and Structures Estimate
Exhibit 2
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 2
Exhibit 2
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 $3,036,300
2 of 2
Exhibit 2
Carlsbad ADA Beach Access Feasibility StudyPreliminary Structures Cost EstimateD. Kasawdish2/20/20191 .ADA Beach Access at Cold WaterStructure Type: Cut and Cover- RC/ PC Box CulvertRamp Length=92.5 LF6 ftPC Box Length per OldcastleCost/ Box= 10,000$ 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 StructuresExhibit 2
P a g e | 17
Trail Connectivity to Tamarack State Beach
Feasibility Study
Appendix C
Environmental Constraints Table
Exhibit 2
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
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
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.
Exhibit 2
ADA BEACH & LAGOON ACCESS
Feasibility Study
Carlsbad, California
SDG PROJECT NO: 18-106
PLT DATE: 07/26/2019
10
ADA BEACH AND LAGOON
ACCESS FEASIBILITY STUDY
XX
Plot Date: 2019-08-12; 03:35pm, Drawing Title: 18-106 X-TBLK.dwg, User ID: mjohnson1
LD,MJ
TS
GS
VICINITY MAP
NOT TO SCALE
ADA BEACH AND LAGOON ACCESS FEASIBILITY STUDY
CONCEPTUAL PLANS FOR:
CITY OF CARLSBAD, CALIFORNIA
CITY COUNCIL
MATT HALL - MAYOR
PRIYA BHAT-PATEL - MAYOR PRO TEM
KEITH BLACKBURN - COUNCIL MEMBER
CORI SCHUMACHER - COUNCIL MEMBER
BARBARA HAMILTON - COUNCIL MEMBER
PAZ GOMEZ
DEPUTY CITY MANAGER,
PUBLIC WORKS
GARY BARBERIO
DEPUTY CITY MANAGER,
COMMUNITY SERVICES
PROJECTSITE
INDEX OF SHEETS
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 COLD WATER TUNNEL
SHEET 8 PHOTO SIMULATION - COLD WATER TUNNEL
SHEET 9 DESIGN CHARACTER
SHEET 10 PLANT PALETTE
PROJECTSITE
LOCATION MAP
NOT TO SCALE
CARL
S
B
A
D
VI
L
L
A
G
E
D
R
5
INTERSTATE
CARLSBAD
B
LVD
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
Exhibit 3
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 & LAGOON ACCESS
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
Exhibit 3
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 & LAGOON ACCESS
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
Exhibit 3
ADA BEACH & LAGOON ACCESS
Feasibility Study
Carlsbad, California
Photo Simulation
Pine Avenue Access
SDG Project Number: 18-106
Date: January 23, 2020 Sheet 4 of 11
Exhibit 3
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 & LAGOON ACCESS
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
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Sheet 5 of 11
Exhibit 3
ADA BEACH & LAGOON ACCESS
Feasibility Study
Carlsbad, California
Photo Simulation
Tamarack Beach Access
SDG Project Number: 18-106
Date: January 23, 2020 Sheet 6 of 11
Exhibit 3
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5
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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 & LAGOON ACCESS
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
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Sheet 7 of 11
Exhibit 3
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 & LAGOON ACCESS
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
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Sheet 8 of 11
Exhibit 3
ADA BEACH & LAGOON ACCESS
Feasibility Study
Carlsbad, California
Photo Simulation
Cold Water Tunnel Access
SDG Project Number: 18-106
Date: January 23, 2020 Sheet 9 of 11Exhibit 3
ADA BEACH & LAGOON ACCESS
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
Exhibit 3
ADA BEACH & LAGOON ACCESS
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
Exhibit 3