HomeMy WebLinkAbout; ; Pacific Coast Shoreline Carlsbad Recon Report; 1994-01-01 (6)COASTAL ENGINEERING APPENDIX
CARLSBAD RECONNAISSANCE STUDY
January 10, 1994
Page
A-1.0 GENERAL , 1
A-1.1 Introduction l
A-1.2 Purpose and Scope 1
A-1.3 Previous Studies by the U.S. Army Corps of Engineers .... 1
A-1.4 Previous Studies by Others 4
A-1.5 Existing Projects / Shoreline Features 4
A-2.0 PHYSICAL SETTING 7
A-2.1 Geographic Setting 7
A-2.2 Bathymetry 7
A-2.3 Regional Coastal Processes 7
A-3.0 CLIMATE 9
A-3.1 General Climatic Conditions 9
A-3.2 Storms and Pressure Field 9
A-4.0 OCEANOGRAPHY 11
A-4.1 Tides and Water Levels 11
A-4.1.1 Tides 11
A-4.1.2 Water Levels 11
A-4.2 Currents 13
A-4.2.1 Offshore Currents 13
A-4.2.2 Longshore Currents 14
A-4.2.3 Cross-shore Currents 14
A-4.3 Waves 15
A-4.3.1 Exposure 15
A-4.3.2 Local Seas and Swell 15
A-4.3.3 Storm Waves 15
A-4.4 Historic Coastal Storm Damages 15
A-5.0 LITTORAL PROCESSES 17
A-5.1 Littoral Cells 17
A-5.1.1 Oceanside Littoral Cell 17
A-5.1.2 Carlsbad Subreach 17
A-5.2 Sediment Sources and Sinks 17
A-5.2.1 Streams, Creeks, and Drainages 17
A-5.2.2 Coastal Bluffs . 18
A-5.2.3 Beach Erosion 18
A-5.2.4 Sediment Sinks 19
A-5.3 Existing Structures, Beachfills, and Dredging History ... 19
A-5.3.1 Existing Structures 19
A-5.3.2 Beachfills and Dredging History 20
A-5.4 Erosion and Accretion Rates 21
A-5.4.1 Historic Shoreline Changes 22
A-5.4.2 Historic Profiles 22
A-5.5 Longshore Transport 23
A-5.6 Sediment Budget 25
A-5.6.1 Historic Sediment Budget 25
A-5.6.2 Sediment Budget for Future Without Project 26
A-6.0 WITHOUT PROJECT CONDITIONS 28
A-6.1 Project Area Description 28
A-6.2 Sediment Transport Along Carlsbad Coastal Area 30
A-6.2.1 Historic Data 30
A-6.2.2 Shoreline Trends 30
A-6.2.3 Storm and Future Without Project Profiles 31
A-6.3 Wave Runup Analysis 33
A-6.3.1 General 33
A-6.3.2 Methods of Wave Runup Calculation 34
A-6.3.3 Statistical Simulation 34
A-6.4 Coastal Storm Damages 36
A-6.5 Estimates of Damages 37
A-6.5.1 Methodology 37
A-6.5.2 Wave Height - Damage Mechanism 40
A-6.5.3 Damage Analysis to Coastal Facilities 40
A-7.0 WITH PROJECT CONDITIONS 44
A-7.1 Planning Criteria 44
A-7.2 Preliminary Basis for Design 44
A-7.2.1 Beachfill 44
A-7.2.2 Groin 44
A-7.2.3 Offshore Breakwater 46
A-7.2.4 Revetment 46
A-7.3 Description of Alternate Plans 47
A-7.3.1 Plan 1 - Beachfill in Reaches 1 and 2 48
A-7.3.2 Plan 2 - A Groin System with Beachfill in Reaches 1
and 2 48
A-7.3.3 Plan 3 - An Offshore Breakwater System in Reaches 1
and 2 48
11
A-7.3.4 Plan 4 - New and Repaired Revetments in Reach 1 . . 48
A-7.3.5 Plan 5 - Beachfill and North Intake Jetty Extension
in Reaches 1, 2, and 3 49
A-7.3.6 Plan 6 - Beachfill in Reach 3 49
A-7.3.7 Plan 7 - A Groin System with Beachfill in Reach 3 . 49
A-7.3.8 Plan 8 - An Offshore Breakwater System in Reach 3 . 49
A-7.3.9 Plan 9 - A Seawall in Reach 3 50
A-7.3.10 Plan 10 - A Rubble-Mound Revetment in Reach 3 ... 50
A-7.3.11 Plan 11 - Beachfill and Structures in Reaches 1,
2, and 3 50
A-7.3.12 Plan 12 - A Rubble-Mound Revetment in Reach 5 ... 50
A-7.3.13 Plan 13 - A Groin System with Beachfill in Reach
1 50
A-7.3.14 Plan 14 - A T-Groin with Beachfill in Reach 3 ... 51
A-7.4 Assessment of Alternate Plans 51
A-7.4.1 Plan 1 - Beachfill in Reaches 1 and 2 51
A-7.4.2 Plan 2 - A Groin System with Beachfill in Reaches 1
and 2 54
A-7.4.3 Plan 3 - An offshore Breakwater System in Reaches 1
and 2 55
A-7.4.4 Plan 4 - New and Repaired Revetments in Reach l . . 58
A-7.4.5 Plan 5 - Beachfill and North Intake Jetty Extension
in Reaches 1, 2, and 3 58
A-7.4.6 Plan 6 - Beachfill in Reach 3 59
A-7.4.7 Plan 7 - A Groin System with Beachfill in Reach 3 . 61
A-7.4.9 Plan 9 - A Seawall in Reach 3 62
A-7.4.10 Plan 10 - A Rubble-Mound Revetment in Reach 3 ... 62
A-7.4.11 Plan 11 - Beachfill and Structures in Reaches 1,
2, and 3 62
A-7.4.12 Plan 12 - A Rubble-Mound Revetment in Reach 5 ... 63
A-7.4.13 Plan 13 - A Groin System with Beachfill in Reach
1 63
A-7.4.14 Plan 14 - A T-Groin with Beachfill in Reach 3 ... 63
A-7.5 Preliminary Costs of Construction and Maintenance 66
A-7.5.1 Rock and Beachfill Unit-Prices 66
A-7.5.2 Construction Materials, Quantities, and Costs ... 66
A-7.5.3 Maintenance Requirements 67
A-8.0 REFERENCES 84
111
LIST OF TABLES
Page
Table 4.1 San Diegc Tidal Characteristics 11
Table 4.2 Oceanside Harbor Extreme Wave Heights 16
Table 5.1 Annual Coastal Bluff Sediment Contribution 18
Table 5.2 fajor Coastal Structures Effecting Longshore Transport .... 20
Table 5.3 Beach Fills and Relevant Dredging Within Carlsbad Study Area . 21
Table 5.4 Summary of Volume Change/Shoreline Values at Carlsbad .... 23
Table 5.5 Oceanside Longshore Sediment Transport Estimates 24
Table 5.6 Net Sediment Transport Rates - Oceanside Littoral Cell .... 25
Table 6.1 Boundary of Reaches - Carlsbad Study Area 28
Table 6.2 Beach Recession at Carlsbad Coastal Area 33
Table 6.3 Water Elevation Statistics at Carlsbad Coastal Area 36
Table 6.4 Wave Runup Statistics at Carlsbad Coastal Area 37
Table 6.5 Data used for Calculation of Bluff Retreat 39
Table 6.6 Revetment Damages - Present and Future Without Project .... 41
Table 6.7 Carlsbad Blvd. Reach 3 Damages - Present and Future Without
Project 42
Table 6.8 Carlsbad Blvd. Reach 5 Damages - Present Without Project ... 43
Table 7.1 Plan 1 - Beachfill in Reaches 1 and 2 - Analysis of Beachfill
Replenishment Frequency without Groins 52
Table 7.2 Carlsbad - Wave Runup Statistics at Reaches 1 & 2 - With
Project 53
Table 7.3 Carlsbad Revetment Damages - With Project Conditions 54
Table 7.4a Plan 2 - A Groin System with Beachfill in Reaches 1 and 2 -
Analysis of Beachfill Replenishment Frequency 56
Table 7.4b Plan 2 - A Groin System with Beachfill in Reaches 1 and 2 -
Analysis of Beachfill Replenishment Frequency 57
Table 7.5 Plan 6 - Beachfill in Reach 3 - Analysis of Beachfill
Replenishment Frequency without Groins 60
Table 7.6 Carlsbad Reach 3 - Road Damage with Project Beachfill .... 61
Table 7.7a Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3 -
Analysis of Beachfill Replenishment Frequency 64
Table 7.7b Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3 -
Beachfill Replenishment Frequency Analysis 65
Table 7.8 Plan 1 - Beachfill in Reaches 1 and 2 - Cost Estimate .... 68
Table 7.9 Plan 2 - A Groin System with Beachfill in Reaches 1 and 2 -
Cost Estimate 69
Table 7.10 Plan 3 - An Offshore Breakwater System in Reaches 1 and 2 -
Cost Estimate 70
Table 7.11 Plan 4 - New and Repaired Revetments in Reach 1 - Cost
IV
Estimate 71
Table 7.12 Plan 5 - Beachfill and North Intake Jetty Extension in
Reaches 1, 2, and 3 - Cost Estimate 72
Table 7.13 Plan 6 - Beachfill in Reach 3 - Cost Estimate 73
Table 7.14 Plan 7 - A Groin System with Beachfill in Reach 3 - Cost
Estimate 74
Table 7.15 Plan 8 - An Offshore Breakwater System in Reach 3 - Cost
Estimate 75
Table 7.16 Plan 9 - A Seawall in Reach 3 - Cost Estimate 76
Table 7.17 Plan 10 - A Rubble-Mound Revetment in Reach 3 - Cost
Estimate 77
Table 7.18 Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3 -
Cost Estimate 78
Table 7.19 Plan 12 - A Rubble-Mound Revetment in Reach 5 - Cost
Estimate 79
Table 7.20 Plan 13 - A Groin System with Beachfill in Reach 1 - Cost
Estimate 80
Table 7.21 Plan 14 - A T-Groin with Beachfill in Reach 3 - Cost
Estimate 81
Table 7.22 Carlsbad - Summary Cost Estimate of Alternatives 82
v
LIST OF FIGURES
Figure 2.1 Location Map of Carlsbad Study Area
Figure 2.2 Bathymetry of Carlsbad Study Area
Figure 4.1 Statistical Distribution of Higher High Water at San Diego
Figure 5.1 Comparison of Profiles by Location from Oceanside Harbor to
Carlsbad Submarine Canyon
Figure 5.2 Summary of Historic Sediment Budget
3 Future Without Project Sediment Budget
la Five Reaches of Carlsbad Coastal Area
lb Reach 1 and Reach 2 of Carlsbad Coastal Area
Ic Reach 3 of Carlsbad Coastal Area
Reach 4 of Carlsbad Coastal Area
Reach 5 of Carlsbad Coastal Area
Typical Structure of Carlsbad - Reach 1, Cross-Section 1 .
Schematic Profile of Carlsbad - Reach 1,
Typical Structure of Carlsbad - Reach 1,
Schematic Profile of Carlsbad - Reach 1,
Typical Structure of Carlsbad - Reach 1,
Figure 5.
Figure 6.
Figure 6.
Figure 6,
Figure 6.
Figure 6,
Figure 6,
Figure 6.
Figure 6,
Figure 6,
Figure 6,
Figure 6.
Figure 6
Figure 6.
Figure 6.
Figure 6,
Figure 6.
Figure 6,
Figure 6.
Figure 6.
Figure 6.
Figure 6,
.id
.le
.2a
.2b
.2c
.2d
.2e
.2f
•2g
.2h
.3
.4
.5a
.5b
.5c
.5d
.6
.7
ISRP
Figure 6.8
ISRP
Figure 6.9
ISRP
Figure 6.10
ISRP
Figure 6.11
ISRP
Figure 6.12
Figure 6.13
Figure 7.la
Figure 7.lb
Cross-Section 1
Cross-Section 2
Cross-Section 2
Cross-Section 3
Cross-Section 3
Cross-Section 4
Cross-Section 4
Cross-Section 1
Cross-Section 1
Cross-Section 2
Cross-Section 2
Schematic Profile of Carlsbad - Reach 1,
Typical Structure of Carlsbad - Reach 1,
Schematic Profile of Carlsbad - Reach 1,
Schematic Profile of Carlsbad - Reach 2 ,
Schematic Profile of Carlsbad - Reach 3 ,
Typical Structure of Carlsbad - Reach 4,
Schematic Profile of Carlsbad - Reach 4,
Typical Structure of Carlsbad - Reach 4,
Schematic Profile of Carlsbad - Reach 4,
Schematic Profile of Carlsbad - Reach 5
Profile CB720 - Analysis of Shoreline and Volume Changes by
Profile CB760 - Analysis of Shoreline and Volume Changes by
Profile CB800 - Analysis of Shoreline and Volume Changes by
Profile CB830 - Analysis of Shoreline and Volume Changes by
Profile OS900 - Analysis of Shoreline and Volume Changes by
Schematic of Structure on Bluff
Bluff Erosion versus Excess Wave Runup
Plan 1 - Beachfill in Reaches 1 and 2 - Schematic . .
Plan 1 - Beachfill in Reaches 1 and 2 - Typical Cross-
Section of Beachfill
Figure 7.2a Plan 2 - A Groin System with Beachfill in Reaches 1
Schematic
Figure 7.2b Plan 2 - A Groin System with Beachfill in Reaches 1 and
and 2 -
Page
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2 -
VI
Typical Cross-Section of Groin 124
Figure 7.3a Plan 3 - An Offshore'Breakwater System in Reaches 1 and 2 -
Schematic 125
Figure 7.3b Plan 3 - An Offshore Breakwater System in Reaches 1 and 2 -
Typical Cross-Section of Offshore Breakwater 126
Figure 7.4a Plan 4 - New and Repaired Revetments in Reach 1 -
Schematic 127
Figure 7.4b Plan 4 - New and Repaired Revetments in Reach 1 - Typical
Cross-Section of Revetment 128
Figure 7.5 Plan 5 - Beachfill and North Intake Jetty Extension in
Reaches 1, 2, and 3 - Schematic 129
Figure 7.6a Plan 6 - Beachfill in Reach 3 - Schematic 130
Figure 7.6b Plan 6 - Beachfill in Reach 3 - Typical Cross-Section of
Beachfill 131
Figure 7.7a Plan 7 - A Groin System with Beachfill in Reach 3 -
Schematic 132
Figure 7.7b Plan 7 - A Groin System with Beachfill in Reach 3 - Typical
Cross-Section of Groin 133
Figure 7.8a Plan 8 - An Offshore Breakwater System in Reach 3 -
Schematic 134
Figure 7.8b Plan 8 - An Offshore Breakwater System in Reach 3 - Typical
Cross-Section of Offshore Breakwater 135
Figure 7.9a Plan 9 - A Seawall in Reach 3 - Schematic 136
Figure 7.9b Plan 9 - A Seawall in Reach 3 - Typical Cross-Section of
Seawall 137
Figure 7.Ida Plan 10 - A Rubble-Mound Revetment in Reach 3 - Schematic . 138
Figure 7.10b Plan 10 - A Rubble-Mound Revetment in Reach 3 - Typical
Cross-Section of Revetment 139
Figure 7.11 Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3 -
Schematic 140
Figure 7.12 Plan 12 - A Rubble-Mound Revetment in Reach 5 - Schematic . 141
Figure 7.13 Plan 13 - A Groin System with Beachfill in Reach 1 -
Schematic 142
Figure 7.14 Plan 14 - A T-Groin with Beachfill in Reach 3 - Schematic . 143
Vll
A-1.0 GENERAL
A-1.1 Introduction
The City of Carlsbad is located about 90 miles south of Los Angeles in
San Diego County, California. As shown in Figure 2.1, Carlsbad has a
shoreline of about 6 miles and is located to the south and downdrift side of
Oceanside Beach and Oceanside Harbor. This appendix summarizes the coastal
processes within the Carlsbad coastal area and presents a range of
alternatives to mitigate potential storm damage and coastal flooding.
A-1.2 Purpose and Scope
The purpose of this coastal engineering analysis of oceanographic and
coastal phenomena at Carlsbad is to assess the vulnerability of the Carlsbad
coastal area to storm damages. This assessment is used to identify the
coastal storm hazard and develop alternate plans to reduce damages.
Evaluation of these plans includes an analysis of hydrodynamic effects,
impacts on coastal processes, the basis for design, and preliminary cost
estimate for each alternate plan.
A-1.3 Previous Studies by the U.S. Army Corps of Engineers
A-l.3.1 U.S. Army Engineer District, Los Angeles. 1980. "Survey Report for
Beach Erosion, San Diego County, Vicinity of Oceanside, California,"
September, 1980. Though the authorized study area was the 7.2-mile shoreline
between the Santa Margarita River and Agua Hedionda Lagoon, the erosion
occurring between Buena Vista Lagoon and Agua Hedionda Lagoon was considered
insufficient as to justify consideration for improvement.
A-1.3.2 U.S. Army Engineer District, Los Angeles. 1984. "Appraisal Report,
Small Navigation Project, Agua Hedionda Lagoon, Carlsbad, California,"
December 1984. The purpose was to develop the information required to decide
whether there was a Federal interest in dredging the shoaled area in the Agua
Hedionda Inner Lagoon in order to maintain recreational activities. The
result of an initial economic analysis indicated a benefit/cost ratio of 0.8
to 1.0. The report recommended that a reconnaissance report should be made to
provide detailed information for the determination of the feasibility of
dredging the shoaled area.
A-l.3.3 U.S. Army Engineer District, Los Angeles. 1989. "Section 103 Small
Project, Reconnaissance Assessment Report, Carlsbad, San Diego County,
California," February 1989. The study area was the causeway section of
Carlsbad Blvd. fronting Agua Hedionda Lagoon between the intake and outlet
jetties. The report developed and evaluated several preliminary alternative
solutions and identified the groin system alternative as the most feasible one
with a benefit/cost ratio of 1.1 to 1.0. The report recommended that funds
should be provided for continuation of studies to the Reconnaissance Study
phase.
A-l.3.4 U.S. Army Engineer District, Los Angeles. 1990. "Section 103 Small
Project, Carlsbad Beach Erosion Control Reconnaissance Study, Carlsbad, San
Diego County, California," May 1990. This report (a) provided the current
status of the Carlsbad Beach Erosion Reconnaissance Study; (b) addressed the
problem of storm damages to the causeway section of Carlsbad Blvd. between the
intake and outlet jetties; (c) gave an estimate of potential damage savings,
recreation benefits, and equivalent project first costs. However, no project
cost data were developed for comparison with the potential benefits, because
the Study was discontinued at the request of the local sponsor prior to plan
formulation for the alternative solutions.
A-1.1.5 U.S. Army Engineer District, Los Angeles. 1990. "Sediment Budget
Report, Oceanside Littoral Cell," CCSTWS 90-2, Coast of California, Storm and
Tidal Waves Study, November, 1990. The MSL (mean sea level) shoreline
retreated at an average rate of 1 ft/year from Central Oceanside to Batiquitos
Lagoon. The result was obtained from compilation of all the data: the NOS
maps (1888 to 1982), aerial photos (1938 through 1988), and 10 Corps profiles
taken at 26 range lines between 1954 and 1988.
A-l.1.6 U.S. Army Engineer District, Los Angeles. 1991. "State of the Coast
Report, San Diego Region," Volume 1 - Main Report, Coast of California, Storm
and Tidal Waves Study. Final - September 1991. This report summarized the
results of the (CCSTWS) for the San Diego Region. The following has been
obtained for the information of changes in the mean higher high water (MHHW)
shoreline: (a) during the first two phases (1940-1960 and 1960-1980), there
were minor changes with occasional small accretions, (b) during the third
phase (1980-1990), the shoreline is experiencing erosion rates which range
from about 1.6 ft/year near the southern reach of the Carlsbad shoreline, 6.5
ft/year at Agua Hedionda Lagoon, and 10 ft/year near Buena Vista Lagoon.
"These erosion trends could be the result of the increased storm activities
during the period 1980-1988 and may be corrected by enhancing the ongoing
nourishment activities such as increasing the present rates and the possible
use of a relatively coarser sand (0.25 mm). A combination of sand nourishment
and some structural solutions, such as groins, offshore breakwaters and
revetments, is a viable solution the prevailing erosion problems along this
important San Diego coastal reach."
A-l.3.7 U.S. Army Engineer Waterways Experiment Station, Miscellaneous Paper
H-78-8, Coastal Processes Study of the Oceanside, California, Littoral Cell.
1978. This study concluded that the gross longshore transport rate at Las
Flores, Oceanside, and Encinitas is approximately 800,000 cy/yr, 1.2 million
cy/yr, and 1.8 million cy/yr, respectively. Also, an estimated 100,000 cy/yr
net of littoral drift was estimated to be moving southerly past Oceanside,
California, with a net volume increase in southerly direction south of the
vicinity of Oceanside. The report also suggested a continuous sand bypassing
system as a partial solution to the erosion problem.
A-1.3.8 U. S. Army Corps of Engineers, Interim Survey of Oceanside Harbor,
Oceanside (Camp Pendleton), California, House Document No. 76. 1965. Report
recommended the adoption of the Oceanside Harbor by providing federal
maintenance dredging of channels and turning basins, and the maintenance of a
1,000-foot south jetty, a 710-foot north groin, and about 1,200 feet of stone
revetment. Maintenance dredging was predicted to be required on a biennial
basis with removal of an average of 200,000 cy/yr. Placement of dredge
material on the beach below the Oceanside pier to replenish downcoast beaches
was recommended and found to be in conformance with the needs of the beach
erosion control project.
A-1.3.9 U. S. Army Engineer District, Los Angeles, Survey Report for
Navigation, Oceanside Harbor, Oceanside, (Camp Pendleton), California. 1963.
This is the District Engineer's report which accompanied the Chief of
Engineers report described above.
A-1.3.10 U. S. Army Engineer District, Los Angeles, General Design of Shore
Protection Works near Oceanside, California. 1960. This memorandum presented
the design basis for a 1.3 million cy protective beachfill which was placed
between the San Luis Rey River and Loma Alta Creek, and for the combined groin
and jetty constructed at Oceanside's Municipal Harbor. The report described
maintenance to include replenishment of a protective beach at suitable
intervals and maintenance of the groin. At the time of the project document
study, protective beach maintenance was estimated to be 25,000 cy/year,
anticipated to be supplied through normal periodic maintenance of the Camp
Pendleton Harbor (Del Mar Boat Basin).
A-1.3.11 U. S. Army Corps of Engineers, Oceanside, Ocean Beach, Imperial
Beach, and Coronado, San Diego County, California, Beach Erosion Control
Study, House Document No. 399. 1957. Recommended a project consisting of
placing a 900,000 cy protective beachfill at Oceanside, generally 200 feet
wide and 10,000 feet long from the vicinity of 9th street to Witherby Street,
at one-third federal cost. The views of the Beach Erosion Board concurred
with the District Engineer's opinion that jetties constructed at Camp
Pendleton Harbor as a wartime measure in 1942 were primarily responsible for
the erosion problem at Oceanside.
A-1.4 Previous Studies by Others
City of Carlsbad. 1989. "City of Carlsbad Proposal for the Carlsbad
Beach Erosion Study and Coastal Shore Protection Project," April 1989. This
report recommended as a feasible solution a 2,200-foot long concrete-capped
sheetpile seawall with revetments at both the north and south ends of the
causeway section of Carlsbad Blvd. between the intake and outlet jetties.
Tekmarine, Inc. conducted a series of semi-annual beach profile surveys
for the City of Carlsbad during the 1987 to 1991 period. The most recent
report is: Tekmarine, Inc. 1992. "Semi-Annual Beach Profile Surveys and
Analysis for October 1991," submitted to City of Carlsbad, California, March
1992. This report concluded that two major factors have been influencing the
beaches near Carlsbad study area: wave climate and sand supply. Reflecting
the impact of the San Diego Gas & Electric Company (SDG&E) beach nourishment
program during December 1990 through April 1991, the profiles along the
Carlsbad shoreline experienced general accretion and the volumetric gains in
the accreted profiles were concentrated mainly above MLLW. When compared with
the survey of October 1990, the shorelines of October 1991 indicated seaward
advance of about 44 ft within Carlsbad, but a retreat of about 35 ft within
South Oceanside. Also, it was concluded that over the past several years, the
shoreline at:
Oceanside Blvd. showed a distinct trend for erosion.
Tamarack Ave. and Acacia Ave appeared to be quasi-stable during this
period.
"All other shorelines in Carlsbad exhibited a trend of advance."
A-1.5 Existing Projects / Shoreline Features
There is no existing federal shore protection or beach erosion control
project at Carlsbad, however, previous beach erosion control projects at
Oceanside and the periodic placement of dredge material from Oceanside Harbor
on Oceanside beach adds sand to the beach system of Carlsbad. Beginning from
the north and working south, the following projects and shoreline features
have been identified along the coastal vicinities of the Carlsbad study area:
Del Mar Boat Basin (Camp Pendleton Harbor) was constructed by the
Navy in 1942, approximately 10 miles updrift of Carlsbad. This
original construction consisted of two short jetties and dredging
of a basin in the low ground between the mouths of the Santa
Margarita and San Luis Rey fivers. In 1957 and 1958, the Del Mar
Boat Basin jetties were extended by the Department of the Navy to
their current alinement.
The South jetty/groin of Oceanside Harbor was constructed to a length of
approximately 1,000 ft in 1961. This was performed by the Corps of
Engineers as a combined federal beach erosion control project and a
locally desired and financed element of the proposed Oceanside Harbor.
A protective beachfill of 3.375 million cy was deposited on the beach at
Oceanside between 1962 and 1963. The borrow site for the beachfill were
the approach channel to the Del Mar Boat Basin and the future Oceanside
Harbor.
A 400 feet long south groin along the north bank of the San Luis Rey
river was constructed in 1961 and was extended by 500 ft in 1968.
Riprap placed along a 1000 ft long stretch at Wisconsin Avenue at
Oceanside in 1949.
Additional riprap placed near Wisconsin Ave. in 1950-1952.
Two groins constructed at Wisconsin Ave. and one groin 1000 ft south in
1952.
A weir at Buena Vista Lagoon was constructed by the local interest to
keep water in the lagoon at low tide.
Private seawalls and revetments have been constructed and repaired
throughout the Carlsbad coastal area where the beaches back private
houses. The reach of shoreline is situated between Buena Vista Lagoon
and Pine Avenue.
Public seawall - from Oak St. to Agua Hedionda Lagoon in 1986.
Intake and outlet jetties at Agua Hedionda Lagoon were constructed in
1954. The intake jetties are about 300 ft long. Construction of the
cooling water system for the power plant also included dredging of about
4 million cubic yards of sand which were placed on the Beach fronting
Agua Hedionda lagoon.
A short rock groin immediately south of the outlet jetty at Agua
Hedionda Lagoon.
Beach between intake and outlet jetties at Agua Hedionda Lagoon.
The most southern man-made features in the Carlsbad coastal area are
situated between Cannon Road and'Cerezo Drive. Virtually all of this
section of the shoreline is armored by either revetment or gunite.
South Carlsbad State Beach.
A-2.0 PHYSICAL SETTING
A-2.1 Geographic Setting
The City of Carlsbad is located about six miles downcoast of the City of
Oceanside and the Camp Pendleton Marine Corps Base, San Diego County,
California, as shown in Figure 2.1. The total length of its shoreline is 7
miles with its northern boundary with the City of Oceanside at Buena Vista
Lagoon and its southern boundary with the City of Encinitas at Batiquitos
Lagoon. The shoreline consists of narrow sand and cobble beaches fronting
nearshore bluffs in the north and south reaches. The central reach shoreline
is a low lying barrier spit, approximately 3,500 feet long, fronting the Aqua
Hedionda tidal lagoon. The SDG&E power plant is located along the shores of
the lagoon and withdraws its cooling water from the lagoon.
A-2.2 Bathymetry
The deep water bathymetry offshore of Carlsbad is shown in Figure 2.2.
Carlsbad is located in the central portion of the Oceanside littoral cell
bounded by Dana Point in the north and Point La Jolla in the south. As can be
seen in Figure 2.2, the bottom contours throughout much of this cell are
gently curving and uniform. The nearshore contours at Carlsbad are relatively
straight and parallel, except where Carlsbad submarine canyon approaches the
shoreline. The head of this canyon is located at approximately the 100-foot
isobath. Nearshore slopes are steeper south of the canyon.
A-2.3 Regional Coastal Processes
Regional coastal processes include the transport, deposition and
erosion of sediment, the impacts of sediment sources and sinks on these
processes, and the short and long term effects of coastal storms on the
coastline.
Waves and wind create the primary coastal currents that transport
sediment in the coastal zone. Due to the alignment of the coastline relative
to incident wave approach, the net transport of littoral drift along Carlsbad
and Oceanside coastal area is from north to south. The presence of coastal
structures such as groins and breakwaters of the Oceanside Harbor complex and
the jetties of the Aqua Hedionda Lagoon results in the disruption of sediment
transport, creating a variety of localized shoreline effects. Sediment
sources to this area on a regional scale include local creeks, storm drains,
and local cliffs.
Three tidal lagoons are located Along the Carlsbad shoreline: Buena Vista
lagoon, Agua Hedionda lagoon, and .Batiquitos lagoon. The former and later
separate Carlsbad from adjacent cities. These lagoons effect coastal
processes through their tidal exchange across the littoral current, disrupting
the continuous longshore flow of sediments and acting as sinks and possible
sources of sediment. In a typical tidal lagoon system, inlet and outlet
shoals play a complex role in storage of sediments, modifying the local wave
action, and in bypassing of littoral materials. A man-made sill at the mouth
of the Buena Vista lagoon has reduced the natural tidal exchange and lessened
the effects of inlet flows on coastal processes. This sill is located at the
elevation of about mean sea level, effectively halving the natural tidal
prism. The sill precludes this lagoon from acting as a sink or source of sand
to the beaches and would have a significant effect on littoral processes only
during periods of high local runoff.
Agua Hedionda lagoon has two jettied channels to the ocean and also has
a tidal circulation dominated by man-made influences. The SDG&E power plant
cooling water is withdrawn from this lagoon with its effluent discharged
through the downcoast outlet. For this reason, flows in the northern channel
are always flooding or near slack. About 130,000 cy per year of sand is
withdrawn into the lagoon based on historic dredging records to keep the
lagoon clear. Dredged sand material are typically placed along the beach
fronting Agua Hedionda or to the north of the northern jetty.
Batiquitos lagoon's tidal prism has also been altered by man-made
construction of the railroad and freeway/highway. The inlet flows have been
so reduced that it is insufficient to maintain inlet stability. Hence the
cobble beach at the mouth to Batiquitos lagoon is normally closed to the ocean
with communication only during periods of heavy rainfall and runoff. The
effect of Batiquitos lagoon as a source or sink of littoral material is
probably negligible.
A-3.0 CLIMATE
A-3.1 General Climatic Conditions
The climate of coastal southern California is generally considered to be
of a semi-arid Mediterranean type, with mild winters characterized by about 10
to 20 inches per year of rainfall. According to USAED, Los Angeles (1986),
the local average wind speed is approximately 7.7 miles per hour, only
slightly higher than those measured in inland areas. Ocean-landmass
temperature variations result in daytime wind patterns dominated by onshore
winds, and nightly patterns dominated by offshore flows. Exceptions occur
during occasional winter storms where wind directions vary, and during Santa
Ana conditions when winds are usually out of the northeast.
A-3.2 Storms and Pressure Field
Ocean swells effecting the study area are generated by three basic
meteorological phenomena: northern Pacific extra-tropical cyclones, eastern
north Pacific tropical cyclones, and extra-tropical storms in the southern
hemisphere.
Extra-tropical cyclones regularly form in the north Pacific from October
through May. These storms usually track across the Pacific in an easterly
direction. These storms have been responsible for the largest waves effecting
the Carlsbad coastal area. The 1982-83 winter storm season resulted from a
series of extra-tropical cyclones which produced severe conditions responsible
for the widespread destruction along the coast of southern California.
Tropical storms or tropical cyclones develop off the west coast of
Mexico during May through November. The tropical cyclones usually track west
to northwest, but have been known to veer to various directions. An average
of 8 or 9 tropical cyclones per year attain hurricane strength in the eastern
north Pacific, however when the hurricanes reach the cooler waters they weaken
and die. If these systems stall or track into an appropriate wave window,
fairly large waves can propagate into the Carlsbad coastal area. Tropical
systems can track up all the way into the southern California area, as
evidenced by the tropical storm of September 1939; however, this is extremely
rare.
During the southern hemisphere winter, large intense low pressure
systems move from west to east across the ocean between Australia and Chile.
Locally these storms can generate very large waves. For the most part this
activity occurs from May to October. It has been proposed that their
frequency of occurrence is bi-modal, with peaks in early and late northern
hemisphere summer. These waves travel'northward across the equator and into
the southern California area. Wave periods are typically long, 16 to 22
seconds. Wave heights reaching southern California typically are small (2 to
4 feet); however, in some instances these can be as large as 12 feet.
10
A-4.0 OCEANOGRAPHY
A-4.1 Tides and Water Levels
A-4.1.1 Tides
Tides along the southern California coastline are of the mixed semi-
diurnal type. Typically, a lunar day consist of two high and two low tides
each of different magnitude. The lower-low normally follows the higher-high
by about 7 to 8 hours, whereas the next higher-high (through lower-high and
higher-low waters) follows in about 17 hours. Tides have a spatial scale on
the order of hundreds of miles, and therefore are similar everywhere along the
open coast in southern California.
The National Ocean Service, NOAA collected 7 months of tide measurements
at Agua Hedionda, Gulf of Santa Catalina and 18 years of measurements at La
Jolla, Pacific Ocean in establishing tidal datums of the 1960 to 1978 tidal
epoch. While the former are directly applicable to the project at the
Carlsbad coastal area, extreme highs may not be represented due to the lack of
measurement in the 1982-83 storm season. Tidal characteristics of both of
these tidal stations are shown in Table 4.1.
Table 4.1 San Diego Tidal Characteristics
San Diego Tidal Characteristics
(Elevation in feet referenced to Mean Lower Low Water MLLW)
Agua Hedionda La Jolla
Highest observed water level
Observed Date
Mean Higher High Water (MHHW)
Mean High Water (MHW)
Mean Sea Level (MSL)
Mean Tide Level (MTL)
National Geodetic Datum - 1929
Mean Low Water (MLW)
Mean Lower Low Water (MLLW)
Lowest observed water level
Observed Date
7.55
14 February 1980
5.05
4 .24
2.29
2.53
(NGVD) 2.58
0.82
0.00
-0.85
16 May 1980
7.81
8 August 1983
5.37
4.62
2.75
2.77
2.56
0.93
0.00
-2.6
17 December 1933
A-4.1.2 Water Levels
The variation of water levels along the shoreline are due principally to
11
astronomical tides (i.e.. tides driven by the moon, sun and planets); storm
surge driven by spatial variation in barometric pressure, wind and wave setup;
and inter-annual large scale oscillations in the circulation and temperature
distribution of the Pacific, commonly referred to as the El Nino Southern
Oscillation (ENSO). Prediction of astronomical tides is well established and
validated by observation. The distribution of tidal characteristics in
southern California has been obtained from Harris (1981). Figure 4.1 shows
the statistical distribution of higher high water at San Diego.
The contribution of the other components to water levels are more random
in occurrence, although not entirely independent, and more variable both
spatially and temporally. Flick (1991) estimated the ten largest positive
tidal residuals at a relatively wave sheltered location in southern California
to range from 0.84 to 1.06 feet over a 30 year period of record. Flick (1991)
also demonstrated that the joint occurrence of the largest residuals with the
highest astronomical tides and/or highest waves were rare, although the
analysis subjectively filtered residuals having durations shorter than 1.5
days.
Wave setup and setdown along the beach profile varies from a minimum
near the wave breaker location and a maximum at the shoreline. Linear wave
theory predicts maximum setdown of about 4 to 5 percent of wave height along a
plane beach and a slightly higher setup. Surf beats or infragravity waves are
thought to be the result of non-linear transformation of energy across the
surf zone. This phenomenon is not precisely understood but is generally
observed with a magnitude of one to several feet during severe wave events.
Long term changes in sea level from the "greenhouse" effect, tectonic
forces and other localized ground movement are relatively small by comparison
to the other components of sea level. The National Research Council (Marine
Board, 1987) considered three plausible future sea level rise scenarios along
the coastline of North America: 0.5 m, 1.0m, and 1.5 m by the year 2100
(relative to 1986) . According to Flick and Cayan (1984), a review of yearly
mean sea level data recorded at San Diego indicates that a rise of 0.7 feet
per century has occurred. If past trends are projected into the future at San
Diego, a sea level rise of at least 0.2 feet would be expected over the next
25 years.
Positive departures from the annual mean occur during strong El Nino
episodes. These meteorological anomalies are characterized by low atmospheric
pressures and persistent onshore winds. Tidal data indicate that five
episodes (1914, 1930 through 1931, 1941, 1957 through 1959, and 1982 through
1983) have occurred since 1905. Further analysis suggests that these events
have an average return period of 14 years with 0.2-foot tidal departures
12
lasting for two to three years. The added probability of experiencing more
severe winter storms during El Nino periods increases the likelihood of
coincident storm waves and higher storm surge. According to Flick and Cayan
(1984), the record water level of 8.35 feet MLLW observed at San Diego in
January 1983 includes an estimated 0.8 feet of surge and seasonal level rise.
Storm surge is relatively small along the Southern California coast when
compared with tidal fluctuations. According to the U.S. Army (1991), storm
surges driven primarily by atmospheric pressure can raise the sea level on the
order of 0.5 feet for two to six days on the average. Extreme stillwater
level departures from astronomical water levels may be as much as one foot or
greater for the severest extratropical events.
A-4.2 Currents
A-4.2.1 Offshore Currents
The offshore currents consist of (1) major, large scale coastal currents
(i.e. California, Davidson, etc.) which constitute the "mean" seasonal
circulation, and (2) tidal and "event scale" fluctuations (time scales 3 to 10
days) which are expected to be superimposed on the "mean" seasonal
circulations. Hickey (1979) defines the constituents of the large scale
California coastal current as follows:
The California Current - the equatorward flow of water off the coast.
According to Schwartzlose and Reid (1972), the mean speed is about 12.5
to 25 cm/sec.
The California Undercurrent - A subsurface northward flow that occurs
below the main pycnocline and seaward of the continental shelf.
According to Schwartzlose and Reid (1972), the mean speeds are low, on
the order of 5 to 10 cm/sec.
The Davidson Current - A northward flowing nearshore current associated
with winter wind patterns north of Point Conception. From the drift
bottle records, Schwartzlose and Reid (1972) found that the Davidson
Current attained speeds as high as 15 to 30 cm/sec.
The Southern California Countercurrent (also called the Southern
California Eddy) - A northward flow in the Southern California Bight
south of Point Conception and inshore of the Channel Islands. According
to Maloney and Chan (1974), velocity maxima in the Countercurrent during
winter as high as 35 to 40 cm/sec have been observed.
13
TIDAL CURRENTS:
Typical shelf tidal currents have peak longshore velocities of roughly
20 cm/sec, although considerable amplification occurs near larger bays.
Although tidal elevations are very well predicted, tidal currents are not.
EVENT SCALE WIND FORCED CURRENTS:
Lentz (1984) presents a detailed analysis of event scale (sub-tidal)
longshore flows observed off Del Mar. The inner shelf is primarily wind
driven while the outer shelf is primarily driven by longshore gradients in sea
level. In both cases the driving term is apparently balanced by bottom
friction. The southern California Bight is a region of relatively light
winds. North of Point Conception winds are stronger and may dominate.
A-4.2.2 Longshore Currents
Longshore currents in the coastal zone are driven primarily by waves
impinging on the shoreline at oblique angles. This wave generated current
and turbulence is the major factor in littoral transport. The surf zone
currents along the Oceanside Littoral Cell is nearly balanced between
northerly and southerly flows, as predicted by previous littoral transport
studies (Hales, 1980). Typical summer swell conditions produce northerly
drifting currents while the large winter storms from the west and northwest
produce southerly currents. Overall, the persistence of the northerly drift
dominates, however, the strength of the southerly drift during major storm
events results in a net southerly longshore transport.
The direction of surf zone currents can be reversed by very local
topographic effects.
A-4.2.3 Cross-shore Currents
Cross-shore currents exist throughout the study area, particularly at
times of high surf. These currents tend to concentrate at creek mouths and
structures, but can occur anywhere along the shoreline in the form of rip
currents and the return flows of complex circulation cells. To date, no
information is available on the quantification of these currents, nor their
effect on sediment transport. Consequently, their significance to the long-
term sediment budget and coastal processes of the study area is unclear.
14
A-4.3 Waves
A-4.3.1 Exposure
The coastal areas of Carlsbad are sheltered somewhat from deep ocean
waves by the offshore Channel Islands. Waves can approach the Carlsbad
coastal area through three wave windows. The southerly window is located
between the coastline of Southern California and San Clemente Island, at
approximately 160 degrees to 245 degrees. A westerly window exists between
San Clemente Island and Santa Catalina Island, at approximately 245 degrees to
285 degrees. A north-westerly window exists between Santa Catalina Island and
the coastline of Southern California, at approximately 285 degrees to 305
degrees.
A-4.3.2 Local Seas and Swell
Local seas and swell in the southern California Bight near San Diego can
be represented by the hindcast of the Wave Information Studies (WIS) for
Station 7 (Jensen, et al. 1992). This hindcast only considered wave
generation in the northern hemisphere, and is therefore augmented by the
Marine Advisors (1961) hindcast for southern swell. Mean wave heights are
about 2 to 3 feet with typical periods ranging from 5 to 17 seconds.
A-4.3.3 Storm Waves
The data on storms waves are obtained from the wave studies described in
the Design Memorandum of Oceanside Harbor of the USAED, Los Angeles (1992) .
These studies hindcasted a total of 67 severe storm events that occurred
during the period 1900 to 1983. Thirty events were selected as pertinent to
Oceanside Harbor. The hindcast data set was transformed for island
sheltering, refraction, shoaling, and depth limitations. An extreme value
statistical analysis results in a set of wave conditions representative of
various recurrence intervals. Table 4.2 shows the wave statistics at
Oceanside Harbor.
A-4.4 Historic Coastal Storm Damages
The coastal areas of Carlsbad are subject to coastal storm erosion and
flooding. The 4-lane divided causeway - Carlsbad Blvd. has been closed about
once every two years due to storm attacks (USAED, Los Angeles, May 1990) .
This stretch of causeway is located between the intake and outlet jetties of
15
Agua Hedionda Lagoon.
Table 4.2 Oceanside Harbor Extreme Wave Heights
Return Period
(years)
I
10
25
50
100
Significant Wave Height
(feet)
10.0
13.5
15.9
17.9
20.0
After US Army Engineer District, Los Angeles 1992.
According to Tekmarine (1992), the beach profiles in the northern reach
of the Carlsbad shoreline were slow to recover after the 1982-1983 winter
storm season. Also, the beach cycle featuring the alternate summer accretion
and winter erosion vanished altogether. However, the cobble beaches in the
southern reach resumed the seasonal beach cycle in 1986.
A major storm hit the California coast during 16 to 19 January 1988.
According to the survey data (September 1987 before storm and January 1988
after storm) collected by the USAED, Los Angeles (1991), the MHHW shoreline of
the Carlsbad coastal area experienced a recession of about 50 feet. By
November 1989, while most of the San Diego region shoreline seemed to have
recovered from the January 1988 erosion, the Carlsbad shoreline still had an
erosion of about 15 feet.
16
A-5.0 LITTORAL PROCESSES
A-5.1 Littoral Cells
A-5.1.1 Oceanside Littoral Cell
According to the CCSTWS of USAED, Los Angeles (1991), the coastline of
the Oceanside Littoral Cell is about 53.5 miles long extending from Dana Point
to the La Jolla submarine canyons. Dana Point, the north end of the cell, is
a near-complete barrier to the littoral transport of sand. Point La Jolla,
the south end of the cell, is also a near-complete barrier. There are six
subreaches within the Oceanside Littoral Cell: (1) La Jolla-Del Mar, (2)
Encinitas-Leucadia, (3) Carlsbad, (4) Oceanside, (5) Camp Pendleton, and (6)
San Mateo-Dana Point.
A-5.1.2 Carlsbad Subreach
The Carlsbad study area lies within the Carlsbad Subreach which consists
of about six miles of coastline. This subreach extends from Buena Vista
Lagoon in the north to Batiquitos Lagoon in the south. Located in the middle
of the subreach are the Carlsbad Canyon and the Agua Hedionda Lagoon.
A-5.2 Sediment Sources and Sinks
There are a variety of sources that supply sediment into the littoral
zone. These sources include erosion from the adjacent watershed with sediments
transported to the beaches via natural streams, creeks and storm drains;
coastal bluff erosion; beach erosion; and artificial beachfills. These
sources are discussed as follows with the exception of artificial beachfills
which are discussed in Section A-5.4.
A-5.2.1 Streams, Creeks, and Drainages
The CCSTWS of USAED, Los Angeles (1991) shows a list of rivers and
streams carrying sediment into the coastal area of the Oceanside Littoral
Cell. The major rivers are the Santa Margarita River with its mouth located
in Camp Pendleton about one mile north of Oceanside Harbor, and the San Luis
Rey River with its mouth emptying to the sea about 6 miles updrift of the
Carlsbad city boundary. The total sediment load arriving at the coast from
the river systems of this littoral cell vary from 53,000 cubic yards/year
according to CCSTWS 88-3 of Simons, Li and Associates (1988) to 426,000 cubic
17
yards/year according to CCSTWS 84-4 of USAED, Los Angeles (1984).
A-5.2.2 Coastal Bluffs
During the CCSTWS 90-2 conducted by Moffatt and Nichol Engineers (1990),
erosion caused by bluff retreat as well as erosion from ravine formation and
surface degradation of coastal terraces were considered. The results are
presented in Table 5.1. Along the undeveloped shoreline of the Camp Pendleton
marine base, active bluff retreat is still occurring, in highly developed
communities south of Oceanside harbor, the majority of the bluffs are
stabilized by revetments and gunite and would only contribute sediments to the
littoral zone during extreme storm events.
Table 5.1 Annual Coastal Bluff Sediment Contribution
ANNUAL COASTAL BLUFF SEDIMENT CONTRIBUTIONS
OCEANSIDE LITTORAL CELL
1933-1987
Sediment Contribution (cubic yards/year)
Location
North Reach
Central Reach
South Reach
Bluffs
0
9,000
23,000
Coastal
Terraces
22,000
310,000
61,000
Total
22,000
319,000
84,000
Total = 32,000 393,000 425,000
Note :
North Reach = Dana Pt. to San Mateo Pt.
Central Reach = San Mateo Pt. to Carlsbad Submarine Canyon
South Reach = Carlsbad Submarine Canyon to Pt. La Jolla
After CCSTWS 90-2 of Moffatt and Nichol Engineers (1990)
A-5.2. 3 Beach Erosion
The rate of shoreline change, which has been obtained from the CCSTWS of
USAED, Los Angeles (1991), is based upon beach profile survey data for the
Oceanside Littoral Cell during three time periods: 1940-1960, 1960-1980, and
1980-1989. From 1940-1980, changes in the mean higher high water (MHHW)
shoreline in the six-mile Carlsbad Subreach have been minor with occasional
small accretions. During the period 1980-1989, this subreach experienced
18
moderate erosion ranging from about 1.6 ft/year near Batiquitos Lagoon, 6.5
ft/year near Agua Hedionda Lagoon, and 10 ft/year near Buena Vista Lagoon.
A-5.2.4 Sediment Sinks
Submarine canyons usually function as partial or near complete sediment
sinks for material transported in the littoral zone. The Oceanside Littoral
Cell has three submarine canyons, namely, the Carlsbad Submarine Canyon in the
cell's central portion and the Scripps and La Jolla Submarine Canyons at the
cell's south end. The head of the Carlsbad Submarine Canyon is in water
depths of about 100 ft. According to CCSTWS 88-2 conducted by Moffatt and
Nichol Engineers (1988), this water depth is deep enough to prevent transport
of littoral sediments into the head of the canyon.
Breakwaters, groins, jetties and headlands effect sediment transport.
Depending upon length and location, jetties and groins can reduce or even
block sediment flow. The north breakwater of Oceanside Harbor is responsible
for retention of material upcoast in an existing fillet, whereas, south beach
is confined by the groin/south jetty of Oceanside Harbor and the north jetty
of the San Luis Rey river.
Sediment entrapped from the beach or nearshore zone by lagoons and
estuaries is not presently significant in the Carlsbad coastal area, with the
exception that SDG&E has been bypassing the sediments trapped by Agua Hedionda
Lagoon. About 130,000 cy of material has been bypassed annually.
Sediment losses to sand dunes are negligible in the Oceanside Littoral
Cell according to the CCSTWS 87-9 conducted by Tekmarine (1987).
Tekmarine (1987) concluded in CCSTWS 87-9 that the small extent of berm
overwash and the infrequency of its occurrence render it insignificant in the
sediment budget of the Oceanside Littoral Cell.
Currently, there are no onshore losses of the sediment, because no sand
mining is occurring on the beaches within the Oceanside Littoral Cell.
A-5.3 Existing Structures, Beachfills, and Dredging History
A-5.3.1 Existing Structures
A series of man-made coastal structures are located within and adjacent
to the Carlsbad study area. These structures, which are listed in Appendix A
19
of USAED, Los Angeles (1991), are presented in Table 5.2 and were previously
described in Section A-1.5.
Table 5.2 Major Coastal Structures Effecting Longshore Transport
Structure
north breakwater
south jetty
south groin
3 groins
intake and outlet
jetties
groin
Location
Oceanside Harbor
Oceanside Harbor
adjacent to and north
of San Luis Rey River
Wisconsin Ave.
Agua Hedionda Lagoon
south of outlet jetty
Type
rock rubble-mound
rock rubble-mound
rock rubble-mound
rock rubble-mound
rock rubble-mound
rock rubble-mound
A-5.3.2 Beachfills and Dredging History
Littoral material has been added to the beaches near the Agua Hedionda
Lagoon by man in significant quantities starting in 1954 and continuing to
1991. These materials were the result of construction and maintenance
dredging from the Agua Hedionda Lagoon by the San Diego Gas and Electric
Company (SDG&E). In 1954, four million cubic yards of new sand were added
adjacent to the Agua Hedionda Lagoon. Maintenance dredging episodes (listed
in Table 5.3), which occurred from 1954 to 1991, recycled about 4.8 million cy
of sand between the lagoon and beach areas over the past 40 years.
A distinction can be made between maintenance dredging of either
Oceanside Harbor or Aqua Hedionda lagoon as compared to new construction
resulting in the placement of sand to nourish the beaches. Maintenance
dredging is the bypassing or redistribution of littoral material already
active in the littoral zone, while new construction adds to the supply of
littoral materials. New construction projects included the construction of
SDG&E power plant in 1954 mentioned previously, a federal beach nourishment
project completed in 1963 which placed 3.375 million cy of material on the
beach at Oceanside from a borrow source which was developed into the Oceanside
municipal harbor, and a second federal beach nourishment project which trucked
922,000 cubic yards of sand from the San Luis Rey river and dumped it on the
20
beach at Oceanside in 1982. The total nourishment amounts to 8.3 million cy
since 1954 or about 200,000 cy/yr.'
Table 5.3 Beach Fills and Relevant Dredging Within Carlsbad Study Area
Dredging History at Agua Hedionda Lagoon:
YEAR
1954
1955
1957
1960
1961
1963
1965
1967
1969
1972
1974
1976
1979
1981
1983
1985
1988
1991
QUANTITY (YD3)
4,000,000
111,000
232,000
370,000
225,000
307,000
222,000
159,000
97,000
259,000
341,000
331,000
398,000
292,000
200,000
447,000
334,000
465,000
ACCUMULATIVE
QUANTITY (YD3)
PLACEMENT with
respect to LAGOON
1,
1,
1,
1,
1,
2,
2,
3,
3,
3,
3,
4,
4,
111,
343,
713,
938,
245,
467,
626,
723,
982,
323,
654,
052,
344,
544,
991,
325,
790,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
NEW SAND NORTH
NORTH
NORTH
NORTH
NORTH
NORTH
NORTH
NORTH
NORTH
NORTH
&
&
&
&
&
&
&
&
&
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
SOUTH
Average = 129,972 yd3/year from 1955 to 1991
Average = 122,542 yd3/year from 1955 to 1979
Data obtained from CCSTWS of USAED, Los Angeles (1991)
A-5.4 Erosion and Accretion Rates
Shoreline changes within the Oceanside littoral cell have been studied
extensively through analysis of historic surveys of the U.S. Army and
Geological Surveys, comparison of aerial photography and comparisons of
relatively recent profile surveys taken for CCSTWS (USAED, Los Angeles, 1991).
In general, the shoreline between Oceanside Harbor and the southern boundary
of the City of Carlsbad at Batiquitos Lagoon has fluctuated in absolute
location over the years due to major storms and coastal construction. Long
term trends of either erosion or accretion at Carlsbad is not evident from the
historic record of available data, since seasonal fluctuations in shoreline
position or sediment volume in the littoral zone are larger than the net long
term changes.
21
Sediment budget analyses suggest that the littoral sub-cell which
Carlsbad is a part of has been accretional since about 1900 due to sediment
input from beachfills, coastal construction, bluff erosion and from the
rivers. However, in the absence of future beachfills with sediment sources
external to the littoral zone, a deficit in sediment supply is predicted and
the littoral cell will be erosional.
A-5.4.1 Historic Shoreline Changes
Historic shoreline positions are shown on Plates A through J for the
Carlsbad area. The earliest shoreline position available in the comparisons
are based on a 1887-1889 USGS survey -- the plan location of the "shoreline"
by these surveys were approximately equal to mean high water. Relative to
more recent surveys in 1972 or the shoreline mapped from January 1988 aerial
photography, the present shoreline is located seaward of the shoreline of 100
years ago throughout most of the City of Carlsbad. This is largely the result
of coastal construction of the power plant at Agua Hedionda. In 1953-54, the
San Diego Gas and Electric Company constructed two pairs of stone jetties; one
to stabilize the inlet of Aqua Hedionda Lagoon and the second pair to serve as
a channel for the discharge of the thermal effluent from the power plant
across the beach. Between March and November 1954, over 4 million cubic yards
were dredged from Aqua Hedionda Lagoon and deposited on the beach extending
from about 3,500 feet north of the lagoon inlet to 2,000 feet south of the
discharge trench. This beachfill widened the Reach 3 beach about 400 feet and
widened the beach an average of 100 feet for a distance of two miles downcoast
of the disposal area (Reaches 4 and 5). (Note: Description of reaches is
given in Section A-6.1, Project Area Description).
The furthest seaward shoreline location occurred in the mid 60's or the
early 80Ts as testimony to the effects of the major beachfill from the Agua
Hedionda power plant in 1954 and the beachfills in Oceanside in 1964 and 1983.
Since that time beach widths have fluctuated with some profiles showing
erosion and some showing accretion. One of the more recent shoreline position
was mapped from aerial photography flown subsequent to a major wave event in
January 1988. This shoreline shows an eroded condition demonstrating the
effects of major storms. The time history of shoreline positions at selected
profiles analyzed in CCSTWS(1991) are included at the Attachment to Coastal
Engineering Appendix.
A-5.4.2 Historic Profiles
Five comparative profiles in the Carlsbad were analyzed in CCSTWS and
22
are shown at the end of this appendix. These profiles document changes across
the nearshore zone between 1934 and 1988, although the data are not always
complete. Like with the shoreline positions, seasonal or storm induced
erosion masks any discernible long-term trend in profile degradation.
Significant depth changes are observed generally to the 20- to 30-foot water
depth, and seasonal changes in the plan location of MLLW have been at least as
large as 200 feet. Also evident in the comparison between profile locations
for the same survey in April 1986 is the pronounced steepening in the
nearshore bathymetry in the southerly direction from Oceanside Harbor to the
Carlsbad submarine canyon (see Figure 5.1). A rocky, erosion resistant shelf
in water depths of 5 to 10 feet apparently extends to about 1000 feet offshore
of reaches 4 and 5 (Profiles CB760 and CB800). Like the shoreline positions
described above, the most recent profile was taken close after the January
1988 storm event and shows an eroded profile.
The relationship between sand volume change to shoreline position change
was analyzed in CCSTWS(1991). The volume changes in the above analysis refer
to that portion extending from the profile base line to water depths of MHHW,
MSL, -10 ft, -30 ft, and -40 ft deviation (from MLLW) where as the beach
surface area or shoreline change refer to the MHHW line. Table 5.4 shows the
computed volume change to shoreline movement ratios which are obtained from
regression analysis.
Table 5.4 Summary of Volume Change/Shoreline Values at Carlsbad
Volume/Shoreline Change Elevation of Computed
(yd3/ft) Volume Change (ft)
0 .13 MHHW
0.24 MSL
0.60 -10 ft MLLW
0.45 -30 ft MLLW
0.51 -40 ft MLLW
A-5.5 Longshore Transport
A number of longshore sediment transport studies have been performed and
reviewed in the Coast of California Study. The general conclusion of these
findings is that the net littoral transport in the Oceanside coastal vicinity
is directed towards the south, with a net transport potential at a rate of
100,000 to 250,000 cubic yards annually.
As shown in Table 5.5, the potential gross transport rates estimated by
23
Hales (1978) increase from the north to the south within the Oceanside
Littoral Cell. The Carlsbad study area lies within the reach of "Oceanside"
in Table 5.5.
Table 5.5 Oceanside Longshore Sediment Transport Estimates
Longshore Sediment Transport Estimates
Oceanside and Vicinity
Location Gross (yd3/yr) Net (yd3/yx)
Las Flores
Oceanside
Encinitas
After Hales (1978)
800,000
1,200,000
1,900,000
120,000
100,000
165,000
One shortcoming of the aforementioned findings is that its basis on wave
energy for estimating longshore transport potential may be greater than the
actual littoral transport given the reality that specific sections of beach
contain no sand cover. Areas where sand cover is sparse and/or transitory
exist typically between Oceanside and Encinitas. In Carlsbad halfway between
Batiquitos Lagoon and Agua Hedionda Lagoon (Reach 4) the sand layer was
measured by jet probing to be about 3.3 feet thick from 5 feet MLLW to 3 feet
MLLW, 0.5 feet thick at -10 feet MLLW, 1.5 feet thick at -20 feet MLLW, and
2.3 feet thick at -30 feet MLLW (Profile CB760 surveyed in late 1987 by
Tekmarine,1988). Profile CB830 (Reach 2) located about 500 feet north of the
intake jetties at Agua Hedionda Lagoon had no sand cover.
Table 5.6 shows estimated actual longshore sediment transport reported
in CCSTWS 90-2 (Moffatt and Nichol Engineers, 1990). From Del Mar to San
Clemente, the southward directed net transport has been identified in the
100,000 to 250,000 cubic yards per year range for the 1945-1977 time period
and in the zero to 40,000 cubic yards per year range for 1978-1987. The
reduction in the transport rate is believed to be related to a significant
change in the wave energy climate during that 10-year period. Also, Table 5.6
shows that Point La Jolla (south end of Oceanside Littoral Cell) acts as an
effective barrier to sediment movement and that Dana Point (north end of
Oceanside Littoral Cell) allows a small quantity of sediment (1,000 cubic
yards per year) to enter the littoral cell from the north.
24
Table 5.6 Net Sediment Transport Rates - Oceanside Littoral Cell
Net Transport Rates (ydVyr)
Headlands 1945-1977 1978-1987
Pt. La Jolla 0 0
San Mateo Pt. < 50,000 0-10,000
Dana Pt. 1,000 < 1,000
Coastline
Del Mar 100,000-250,000 0-40,000
Encinitas 100,000-250,000 0-40,000
Oceanside 150,000-250,000 0-40,000
Las Flores 50,000-125,000 0-15,000
San Clemente 100,000-150,000 0-20,000
Note: All transport rates are directed towards the south.
After CCSTWS 90-2 of Moffatt and Nichol Engineers (1990)
A-5.6 Sediment Budget
A-5.6.1 Historic Sediment Budget
A sediment budget provides a conceptual model of littoral processes by
accounting for volume changes and sediment fluxes within cells and across cell
boundaries. The sediment budget presented in Chapter 9 of CCSTWS (USAED Los
Angeles, 1991) covers possible scenarios over the past 90 years. Carlsbad is
located within the central sub-cell of the Oceanside littoral cell of their
analysis, which is summarized on Figure 5.2. Three historic time periods were
analyzed: 1900-38, 1960-78, and 1983-90. The first period can be viewed as
the "natural" shoreline condition prior to Oceanside Harbor and the power
plant at Agua Hedionda, however by 1900 the watershed and coastal lagoons had
been significantly altered by construction of roads, railroads and water
supply and flood control works (see chronology of events in the Oceanside
littoral cell at the Attachment to Coastal Engineering Appendix). During this
period, the beach cell gained material with large contributions from bluff
erosion and from major flood events on the Santa Margarita and San Luis Rey
Rivers. Large losses were assumed to the offshore while the net longshore
transport downcoast is assumed equal to the transport potential of available
wave energy.
The second period between 1960-78 includes the effect of the Oceanside
Harbor and the power plant over what some have considered a relatively benign
25
period of storm and wave activity. In this scenario the central sub-cell
gained 40,000 cy/yr. Significant'contributions are shown from beachfills and
bluff erosion. Oceanside Harbor is shown deflecting 80,000 cy/yr to the
offshore and the net downcoast transport is equal to the previous period.
The last period between 1983-90 is a period thought to be of unusually
larger than normal northerly directed longshore transport. The beach cell
gained material at a rate of 60,000 cy/yr with most of the beach material
derived from eroded bluffs. The net downcoast transport is estimated at
70,000 cy/yr for this time period due to the aforementioned unusual wave
climate.
Prior to 1942, longshore sediment transport in the Oceanside littoral
cell was not significantly influenced by man-made structures. In 1942-43, the
U.S. Navy constructed Camp Pendleton Harbor (now known as the Del Mar Boat
Basin) with two arrow head jetties about 1,300 feet long. The northern jetty
was extended by about 2,300 feet by the Navy in 1957-58 to form the North
Breakwater, and further jetty construction and dredging in the 60's and 70's
by the City of Oceanside and the Corps of Engineers eventually evolved into
what is now the Oceanside Municipal Harbor. Since the initial construction of
the original jetties, the shoreline immediately up and downcoast of the harbor
has advanced seaward, while the shore fronting the City of Oceanside
experienced severe erosion. This erosion has been somewhat mitigated by
beachfill projects and the placement of dredge material from Oceanside Harbor
on the Oceanside beach area. The influence of Oceanside Harbor on the
shoreline of Carlsbad is not apparent in the recorded data since construction
of the Agua Hedionda jetties and beachfill masks historic "natural" long-term
trends, and since the normal seasonal variations in shoreline position or
sediment volume in the littoral zone are larger than any long-term net change.
While this indicates a relatively stable shoreline, a contribution of this
stability results from erosion being limited by protective works, i.e.
revetments, seawalls and gunited slopes, or the shallow erosion resistant
hardpan which is along the shoreline throughout most of Carlsbad.
A-5.6.2 Sediment Budget for Future Without Project
Historic sediment budget analyses and the assumption that there will be
no new beachfills in the future forms the basis for estimating a future
sediment budget. The most probable future wave climate is expected to be
similar to the 1900-78 time period. Site investigations also revealed that
bluff erosion will be negligible south of Oceanside Harbor to at least
Batiquitos Lagoon due to protective seawalls and gunite slopes. The continued
maintenance dredging of Oceanside Harbor with placement of about 200,000 cy/yr
26
on beaches to the south is assumed, and a net downcoast transport which is
less than or equal to the transport potential of available wave energy is
predicted due to the paucity of sand. As shown in Figure 5.3, the future
without project sediment budget has an annual loss from the central Oceanside
littoral sub-cell of 90,000 cy/yr -- about 30,000 cy/yr of it eroding from the
Carlsbad shoreline. An average erosion rate of about 1 foot per year would be
anticipated in the Carlsbad study area until the shoreline is denuded of sand
exposing a more erosion resistant hardpan or cobble beach. As discussed in
Section A-6.1, the typical winter beach at Carlsbad is lacking sand with the
exception of Reach 3. The sediment deficit would show as a smaller or non-
existent seasonal summer beach and profile deepening at Reach 3.
27
A-6.0 WITHOUT PROJECT CONDITIONS
A-6.1 Project Area Description
As shown in Figure 6.la, the coastal area of Carlsbad has been divided
into five reaches to discern the shoreline features. The demarcation of each
reach is mainly based on the type of coastal structures and general shore
type. Figures 6.Ib through 6.1e. show the details of each reach. Table 6.1
shows the approximation location of the reach boundaries. The streets running
in the east-west directions are used to indicate the location of the reach
boundaries.
Table 6.1 Boundary of Reaches - Carlsbad Study Area
Boundary
Reach Northern Southern
1 City Boundary of Pine Ave.
Oceanside & Carlsbad
2 Pine Ave. Tamarack Ave.
3 Tamarack Ave. 700 ft north of Cannon Rd.
4 700 ft north of Cannon Rd. 400' north of Cerezo Dr.
5 400' north of Cerezo Dr. City Boundary of
Carlsbad & Encinitas
In order to analyze the five reaches, generalized cross-sections have
been developed for each of the reaches. While Reaches 2, 3, and 5 are
essentially uniform throughout, important variations require that Reaches 1
and 4 contain multiple cross-sections.
A-6.1.1 Reach 1 (Buena Vista Lagoon to Pine Avenue)
Reach 1 extends for a length of about 4,000 feet and its natural
shoreline is typified by a narrow seasonal beach fronting coastal bluffs
ranging in height from 20 to 40 feet. The beach consists of a thin veneer of
sand and cobbles overlying a dense sand hardpan. The reach is entirely
developed with singe and multi-family structures, some protected by stone
revetments and some by concrete sea walls. Four cross-sections are used to
-epresent typical structures within Reach 1.
Section 1, the most common cross-section in Reach 1, represents those
properties in which the first floor of the structure is near the top of the
28
bluff and the toe is protected by revetment composed of armor stones weighing
from 0.5 to 2 tons. The photographs of typical structures are shown in Figure
6.2a. The schematic profile of Section 1 is represented in Figure 6.2b. (The
profiles indicated as maximum, mean, minimum, and hard pan are explained in
Section A-6.2.3).
Sections 2, 3, and 4 of Reach 1 represent important variations from
Section 1. Section 2 (Figures 6.2c and 6.2d) represents the Beach Terrace
Inn, 2775 Ocean Street, and two private structures immediately to the south of
it. These structures are unique because they are protected by a seawall at
close proximity to the water line. The first floor elevations of these
structures range from +19 to +23 feet MLLW. Section 3 (Figures 6.2e and 6.2f)
represents the Sea Slope Condominium complex, 2955 Ocean Street. This
structure is protected by riprap and has a first floor elevation of
approximately +19 feet MLLW. Section 4 (Figures 6.2g and 6.2h) represents 10
unprotected (or marginally protected) structures towards the south end of the
reach. This section represents structures that have first floor elevation
situated at about +43 feet MLLW.
A-6.1.2 Reach 2 (Pine Avenue to Tamarack Avenue)
Reach 2 extends a length of about 3,400 feet and its shoreline is
typified by the public seawall. As shown in Figure 6.3, the structures within
Reach 2 are protected by the public seawall constructed by the City of
Carlsbad. The top of the seawall is situated at about +23 feet MLLW.
A-6.1.3 Reach 3 (Tamarack Avenue to Cannon Road)
Reach 3 consists of about one mile of shoreline backed by Carlsbad Blvd.
The main features are the Agua Hedionda Lagoon, the intake and outlet jetties,
and the Tamarack Parking Lot. The lowest elevation of Carlsbad Blvd. within
Reach 3 is about +17.1 feet MLLW. Figure 6.4 shows a typical cross-section of
Reach 3.
A-6.1.4 Reach 4 (Cannon Road to Cerezo Drive)
Reach 4 extends for a length of about 2,000 feet and its main feature is
the Terra Mar Development. This reach has also been analyzed using multiple
cross-sections. Of the 27 structures, the northern 15 are protected by riprap
and are represented by Section 1 (Figures 6.5a and 6.5b). The remaining
structures are protected by gunite and are represented by Section 2 (Figures
29
6.5c and 6.5d).
A-6.1.5 Reach 5 (Cerezo Drive to Batiquitos Lagoon)
Reach 5 extends for a length of about 5.3 miles and its main feature is
the South Carlsbad State Beach which is backed by the Carlsbad Blvd. Other
features of the South Carlsbad State Beach are parking lots, stairways, and
restrooms. A portion of the Carlsbad Blvd., which is situated behind a
narrow, cobble beach, is an old Coast Highway bridge (circa 1923) where its
crown dips down to an elevation of +18.3 feet MLLW. Figure 6.6 shows a
typical cross-section of Reach 5.
A-6.2 Sediment Transport Along Carlsbad Coastal Area
A-6.2.1 Historic Data
Available data on the historic shoreline response is discussed in
Section A-5.4 and reproduced at the end of this appendix. These data consist
of beach profiles, shoreline change maps, and aerial photographs analyzed in
the CCSTWS conducted by USAED Los Angeles (1991). Additional recent profile
surveys (1990 to 1992) are available from Tekmarine Inc.
A-6.2.2 Shoreline Trends
The most precise data for evaluating changes in the shoreline are the
surveyed profiles. Five of these profiles located in the Carlsbad area are
CB720, CB760, CB800, CB830, and OS900. The location of these profiles are
shown on maps located at the Attachment to Coastal Engineering Appendix.
The profiles were analyzed for volume and shoreline changes using ISRP
(Interactive Survey Reduction Program) and its associated utilities available
for the Coastal Engineering Research Center's Field Research Facility,
(Birkemeier and Holme, 1992). Figures 6.7 to 6.11 summarize the results.
CB720. Profile line CB720 is located just south of the inlet to the
Batiquitos Lagoon but may be representative of shoreline changes in Reach 5.
The profile history extends to 1934 and was analyzed up to January 1988. Only
those surveys which extended to at least the -20 ft MLLW water depth were
utilized in the comparison. Between 1934 and January 1988, the net position
change of MLLW has been 165 feet closer to shore, i.e. erosion, equating to a
long term rate of -3 feet/year. However, between 1934 and October 1986, there
was a 19 foot seaward movement of the MLLW, equating to a net long term
30
accretion of 0.4 feet/year, and a short term erosion between October 1986 and
January 1988 of more than 131 feet/year. The cumulative volume changes are
less cyclical and trends since about 1970 at an erosion rate of about -8 cubic
yards per foot of beach per year.
CB760. Profile CB760 is located at the northern end of South Carlsbad
State Beach approximately at the boundary between reaches 4 and 5. There were
four profiles that extended to at least the -20 foot depth taken between April
1986 and September 1987. During this period the MLLW advanced seaward about
122 feet and the volume change between the baseline and 2000 feet offshore
increased by 4 cy/ft (rate of 5.8 cy/ft/yr).
CB800. Profile CB800 is located off of the Terra Mar area in Reach 4.
Surveys were available to the -20 foot depth between October 1970 to September
1987. Both the position of the MLLW line and the cumulative volume change is
accretional by comparison to the first survey. In September 1987, the MLLW
line had advanced 160 feet by comparison to October 1970. It should be noted,
however, that severe erosion was observed as a result of the January 1988
storm at locations where surveys were performed and would also have been
expected at this location.
CB830. Profile CB830 is located about 500 feet north of the northern
inlet to Agua Hedionda Lagoon. Survey data were available for the two year
period between April 1986 and January 1988. The trend in position of the MLLW
line and the sediment volume appear contradictory for these available surveys
where when the MLLW shows erosion, the volume change is accretional and vice-
versa. These data can only be used as an indication of the magnitude of
seasonal activity and near term transport capacity of the profile. With
regard to the latter, more than 60 cy/ft of beach were found to be transported
in the six month period between April and October 1986.
05900. Profile OS900 is located to the north of Carlsbad in South
Oceanside. This profile may be representative of Reach 1. Seven profiles
were available with data to -20 foot depths between September 1961 to January
1988. Utilizing the 1961 survey as the basis for comparison shows a
relatively stable shoreline with the exception of the eroded condition in
January 1988. The long term volume loss between 1961 and 1988 is about 0.5
cy/ft/yr.
A-6.2.3 Storm and Future Without Project Profiles
The January 1988 survey is representative of the eroded profile
condition during a severe winter storm condition. During damaging storm
31
events, a winter or storm profile would typically exist. This storm profile
is deepened in the nearshore depending'on the severity of the individual storm
and the cumulative effects of the storm season. The long-term future
shoreline also considers a net change in the average shoreline position to
account for changes in the local sediment budget. For analysis purposes, the
profiles taken in January 1988 were selected as representative of the present
eroded winter profile that would exist during a storm event.
The long term evolution of the future without project shoreline
considered temporal changes in the sediment budget. From the sediment budget
analysis in Section A-5.7, the shoreline at mean sea level is predicted to
retreat at an average rate of 1 foot per year for the next 50 years. Thus, a
50-foot shoreward recession in the present shoreline has been obtained for the
future without project condition. However, the retreat rate of 1 foot per
year only applies to the summer beaches, due to the fact that the winter
beaches have already moved to about the limit of shoreward retreat. The
winter recession of the shoreline for all the reaches, with the exception of
Reach 3, is limited by the non-erosive hardpan, revetment, and seawall. At
Reach 3, the retreat rate of 1 foot per year is applied to the winter beach.
Storm effects on the profile were super-imposed on the present and
future shoreline. It is rationalized that storm profile response would be
directly related to storm severity and wave height, and therefore return
period. Based on the analysis of the shoreline data presented in CCSTWS of
USAED, Los Angeles (1991), shoreline retreat can be correlated with return
period as shown in Table 6.2. The shoreline retreat corresponding to an
exceedance probability of 1 % or a return period of 100 years was obtained by
assuming a Gaussian distribution for the shoreline data.
The shoreline data presented in CCSTWS of USAED, Los Angeles (1991) from
1983 to 1988 have been analyzed to gain more insight of the seasonal movement
of the shorelines. In Figures 6.2 through 6.6, the average profiles for the
present conditions are indicated as the maximum, mean, and minimum profiles.
The maximum profile represents the highest beach profiles and the minimum
profile represents the deepest beach profiles, but not necessarily indication
of the season. The mean profile is the average of all of the survey profiles.
These profiles have been obtained by an analysis of the shoreline data by
VOLUME-PC. VOLUME-PC, which is a program for processing beach and nearshore
survey data on an IBM compatible micro-computer, is a complementary program to
ISRP-PC (the Interactive Survey Reduction Program) and ISRPSORT (a sorting
program). The hard pan profile, which is obtained from analysis of the
available geotechnical data, is an indication of possible maximum scour.
32
Table 6.2 Beach Recession at Carlsbad Coastal Area
CB 720 Summer to Winter Shoreline Retreats:
Shoreline Retreats (ft)
ITEM
Mean
Maximum
Minimum
Standard Deviation
1 % Exceedance
2 % Exceedance
4 % Exceedance
10 % Exceedance
MHHW
31.25
39
20
9.00
52
50
47
43
MSL
70.25
81
49
14.55
104
100
96
89
MLLW
190
227
165
26
252
245
237
225
.50
.10
A-6.3 Wave Runup Analysis
A-6.3.1 General
As waves encounter certain types of coastal structures, the water rushes
up and sometimes over the structure. These closely related phenomena, wave
runup and wave overtopping, often strongly influence the design and the cost
of coastal projects. Wave runup is defined as the vertical height above
still-water level to which the rush of water reaches on the structure (of
assumed infinite height). The waves are assumed to be normally incident to
the structure.
The empirical results introduced in the Shore Protection Manual (1984)
and the Automated Coastal Engineering System, Version 1.07 dated September
1992, have been used to calculate the results of wave runup. Along each of
the nine profiles shown in Figures 6.2 through 6.6, the nearshore area of the
project site has been approximated by a uniform slope running from the bottom
up to the depth at which the structure is located. Then another slope is used
to represent the structure. The still water level used in each wave runup
calculation is a summation of the tide level and wave setup.
Wave Setup:
The phenomenon of wave setup causes a quasi-linear rise in the mean
water level due to onshore mass transport of the water by wave action alone.
This phenomenon is associated with the existence of a stress acting on the
water due to the presence of wave motion, called the radiation stress. Its
33
magnitude is related to the momentum flux accompanying wave propagation. The
mean water surface slopes upward to the point of intersection with the shore.
The results of wave setup have been calculated using the method introduced in
the Shore Protection Manual (1984). The input parameters required for each
wave event are the deepwater wave height and period and the nearshore slope of
the sea bottom.
A-6.3.2 Methods of Wave Runup Calculation
The Automated Coastal Engineering System, Version 1.07 (ACES 1.07) has
been used to calculate the wave runups. ACES 1.07 uses the empirical method
presented by Ahrens and McCartney (1975) for estimating the runup on
structures protected by various types of primary armor faces. In their
method, the runup R is predicted as a nonlinear function of the surf
similarity parameter 5:
where Hi is the incident wave height; and a and b are the empirical
coefficients associated with the corresponding types of armor unit. For the
case of ripraps, a equals 0.956 and b equals 0.398 according to Table A-3 of
Appendix A in ACES 1.07. The surf similarity parameter 5 is defined as
(6.2)
where 6 is the angle between the structure seaward face and the horizontal;
and L0 is the deepwater wavelength.
A-6.3.3 Statistical Simulation
The extreme wave runups were calculated using the design water depths at
the structure toe. The design water depths and their corresponding
probabilities were obtained through a joint probability simulation of possible
joint combinations of storm wave events, astronomical tides and the combined
residual water level resulting from ENSO, storm surge and wave setup. The
frequency distribution of the higher high waters was utilized for the
astronomical tide which corresponded to an average storm duration of one lunar
34
day. Independence was assumed between astronomical tide and storm events.
The combined effects of storm surge, wave setup, and ENSO were dependent on
storm event and were assumed to be dominated by the effect due to wave setup.
For each condition (present condition and future without project
condition) and reach cross-section, the joint probability model was run for
all combinations of tide elevation, wave period, and significant wave height
to obtain the design water depths. Each combination of wave period and wave
height was used to obtain the corresponding value of wave setup. The
resulting design water depth used in the calculation of wave runup was the
summation of wave setup, tide elevation (above mean sea level), and the
initial design water depth dso (below mean sea level). The statistical
distribution of higher high water shown in Figure 4.1 was discretized
according to Harris (1981), resulting in 101 tidal elevations. Each tidal
elevation had an assigned probability according to Harris (1981). Four wave
periods, namely, 13, 15, 17, and 19 seconds, were used in the joint
probability calculations. The 13, 15, 17, and 19-second waves were assumed to
have probabilities of 0.1, 0.2, 0.4, and 0.3, respectively. The extreme wave
heights shown in Table 4.2 were discretized into 13 waves, from 10 ft to 22 ft
with 1-ft increment. The probability of each wave was obtained by linear
interpolation of the exceedance distribution to plus and minus 0.5 ft of the
wave. Thus, a total of 5,252 trials were obtained from each joint probability
simulation. The resulting design water depths were ranked in descending
order, with the corresponding probability of each depth attached. Then the
probabilities were summed to obtain the exceedance probability. Table 6.3
shows the deign water depth versus return period for each coastal reach and/or
section. During the calculation of the design water depth for each coastal
reach, the same profile was used for all of the return periods. Besides the
present condition, the 50-year future condition is shown for Reach 3. The
future condition has been obtained by scouring the initial water depth to the
depth of the hard pan. The present profiles of the other four reaches are not
expected to have further vertical scour, because their initial water depths
are close to the depth of the hard pan. Thus, the design water depths for the
future conditions of Reaches 1, 2, 4, and 5 will remain the same.
Then the runup elevation corresponding to each design water depth and
structure slope was calculated by using ACES 1.07. The breaking wave height
that could be sustained by the design water depth had been used to calculate
the runup level. For each reach and/or section, two sets of runup levels had
been calculated, one set using a wave period of 15 seconds and another set
using 17 seconds. The resultant runup levels were obtained by combining these
two sets of runup levels, so that the runup level with the 2-year return
frequency was that of the 15-second set and the runup level with the 200-year
return frequency was that of the 17-second set. The runup levels of the other
35
return frequencies were obtained by interpolating between the two sets of
runup levels. The resulting probability distribution of wave runup elevations
were used in the damage analysis (Section A-6.5.4). Table 6.4 shows the wave
runup elevation versus return period by coastal reach and/or section.
Table 6.3 Water Elevation Statistics at Carlsbad Coastal Area
Carlsbad Design Water Depth Analysis:
Design Water Depth (FT)
(FT) COT COT
LINE Dso T B 2-YR 5-YR 10YR 25YR 50YR 100YR 200YR
Rl SI
Rl S2
Rl S3
Rl S4
REACH 2
REACH 3
R4 SI
R4 S2
REACH 5
REACH 3 9.0 4.9
2
2
2
2
2
4
2
2
3
.3
.3
.3
.3
.4
.5
.8
.8
.0
3
2
4
3
2
4
3
2
2
.5
.0
.0
.3
.0
.9
.0
.5
.5
51
51
51
51
54
60
58
58
57
.0
.0
.0
.0
.0
.0
.0
.0
.0
•esent Condition
7.6
7.6
7.6
7.6
7.8
9.9
8.2
8.2
8.4
8
8
8
8
8
10
8
8
9
.4
.4
.4
.4
.5
.6
.9
.9
.1
8
8
8
8
8
11
9
9
9
.8
.8
.8
.8
.9
.0
.3
.3
.5
9
9
9
9
9
11
9
9
9
.1
.1
.1
.1
.3
.4
.7
.7
.9
9
9
9
9
9
11
9
9
10
.3
.3
.3
.3
.5
.6
.9
.9
.1
9
9
9
9
9
11
10
10
10
.5
.5
.5
.5
.6
.8
.1
.1
.3
9.7
9.7
9.7
9.7
9.8
12.0
10.3
10.3
10.4
50-year Future Condition
60.0 14.4 15.1 15.5 15.9 16.1 16.3 16.5
Notes:
Rl SI = Reach 1, Cross-section 1, etc.
Dso = Initial design water depth below mean sea level
COT T = Structure slope
COT B = nearshore slope
Design Water Depth = Wave setup + Tide + Dso
A-6.4 Coastal Storm Damages
Coastal storm damages at the Carlsbad study area are the results of
flooding due to wave runup, excessive forces from high velocity wave runup
action, and storm induced erosion undermining foundations, etc. For instance,
the causeway (Carlsbad Blvd.) between the intake and outlet jetties of Agua
Hedionda Lagoon has been closed, in recent years, on the order of once every
two years due to coastal storm attacks.
36
Table 6.4 Wave Runup Statistics at Carlsbad Coastal Area
Line
Rl SI
Rl S2
Rl S3
Rl S4
Reach 2
Reach 3
R4 SI
R4 S2
Reach 5
2-yr
17.6
19.6
17.1
17.8
20.0
18.2
19.0
19.8
19.9
Carlsbad Wave Runup Level (ft MLLW)
5-yr
19.3
21.5
18.7
19.6
21.7
19.5
20.6
21.4
21.5
10-yr 25-yr 50-yr 100-yr
Present Condition
20
22
19
20.5
22.7
20.4
21.4
22.2
22.5
21.0
23.3
20.4
21.2
23.7
21.2
22.4
23.3
23.5
21.4
23.8
20.8
21.7
24.2
21.7
22.9
23.8
23.9
21.9
24.4
21.3
22.2
24.5
22.2
23.4
24.2
24.5
200-yr
22.5
25.0
21.8
22.7
25.1
22.7
23.9
24.8
24.9
Reach 3 21.4
50-year Future Condition
22.7 23.5 24.3 24.8 25.4 25.8
A-6.5 Estimates of Damages
A- 6 .5.1 Methodology
Projections of damages to the coastal facilities were developed
utilizing projections of shoreline response, expectations of wave runup
elevation, and a site visit to judgementally assign a damage-wave runup
relation for each individual property within the study area. This damage
relation takes into consideration the type of improvements and existing
protection afforded by revetments and seawalls, the proximity of improvements
to the active wave runup zone, the type of foundations and vulnerability to
structural damages due to undermining and flanking, and the susceptibility to
coastal flooding. Projections of future damages were developed for Reach 3.
The Carlsbad coastal area is divided into five reaches of homogeneous
structure type, since the damage-wave runup function is dependant on the type
of structure. These reaches are shown in Figure 6.1.
Damages to existing revetments:
Damage to revetments is estimated by calculating the forces acting on
the revetment stones due to breaking waves. Basing on the stone size and
revetment slope, the Hudson formula has been used to calculate HD=0 which is
37
the design wave height corresponding to the no-damage condition. The
stability coefficient KD has been 'assumed to be 2.0. The breaking wave height
HB for each reach is calculated by using the design water depths and nearshore
slope shown in Table 6.3. Also, a wave period of 17 seconds has been used.
Equation 7-5 on page 7-9 of the SPM (1984) has been used to calculate HB.
With the ratio of HB to HD=O/ the percent damage D for rough quarrystone armor
is obtained from Table 7-9 of the SPM (1984).
Damages to ancillary improvements:
Ancillary improvements, such as landscaping, stairways, and restrooms,
are damaged when the wave runup level exceeds the elevation at which these
ancillary improvements are situated.
Structural Damages due to Bluff Retreat:
Approximately 20 structures are subject to structural damage due to
erosion of the bluff and undermining of foundations. These structures are
located primarily along a 620 foot length of unprotected shoreline in Reach 1,
Section 4. Structures are multi-family units, typically built with concrete
grade beams and slab foundations cut into the bluffs backing the beach. The
foundation elevations range from about +25 to +38 feet MLLW, while the toe of
the bluffs is located at about +13 feet MLLW. Table 6.5 shows the foundation
elevations of ten structures. Also shown in the table are horizontal distance
of: foundation to +13 feet MLLW, projected by the 1.5:1 slope, and structure
to bluff edge. Figure 6.12 shows a schematic drawing of a structure on the
bluff. Extreme storm events have resulted in erosion at the toe of these
coastal bluffs and the slumping of the bluffs fronting these structures.
Although little historic information on magnitude and extent of bluff retreat
are available for this specific location, anecdotal reports and review of
aerial surveys suggest that bluff retreat along Reach 1 were as high as 13 and
20 feet in localized areas during the 1983 and 1988 storms, respectively,
while over a longer 170 foot length of shoreline at the north end of the
Carlsbad shoreline, bluff retreat appears to have averaged about 8 feet as the
result of the 1988 storm event. Figure 6.13 displays a simple linear
correlation of bluff retreat with runup level above the toe of the bluff
through the available data. Approximating the distance of lateral retreat as
proportional to excess runup allows assigning a return-period estimate to
bluff retreat distance. Excess runup is the result of runup elevation
subtracting the bluff toe elevation of +13 feet MLLW.
The damage assumptions applied to the loss of structures are as follows:
1) Structure foundation are grade beam or slab.
2) Limiting stable bluff slope is 1.5H:1V.
3) Initiation of damage occurs when top of the average eroded bluff
with a slope at 1.5H:1V reaches the closest foundation and complete damage
38
occurs when the bluff erosion reaches the furthest recessed structure (see
Figure 6.12) .
Utilizing these assumptions, initiation of damages due to bluff retreat
undermining structure foundations initiate at the 50-year event while complete
structural damage occurs along this vulnerable reach occurs at the 100-year
event.
Table 6.5 Data used for Calculation of Bluff Retreat
Horizontal Distance (ft) of
Elevation of
House Foundation (ft)
1 25
2 25
3 32
4 32
5 27
6 30
7 32
8 25
9 22
10 35
Foundation
to +13'MLLW
46
46
75
65
50
55
70
70
60
65
Projected
by 1.5:1 Slope
38
38
48
48
41
45
48
38
33
53
Structure to
Bluff Edge
8
8
27
17
9
10
22
32
27
12
Coastal flooding damages:
Structures that have their first floor elevation lower than the wave
runup elevation are subject to flooding damages. The estimate of flooding is
based on the magnitude of excess runup. Excess runup is the result of runup
elevation subtracting first floor elevation. The flood elevation is assumed
to be 35% of the excess runup.
Erosion damages at Carlsbad Boulevard:
The section of Carlsbad Blvd. located between the intake and outlet
jetties of Agua Hedionda Lagoon is subject to erosion damages. The estimate
of road erosion is based on the magnitude of excess runup. Excess runup is
the result of runup elevation subtracting the road elevation of +16.8 feet
MLLW. According to the study of USAED, Los Angeles (May 1990), a horizontal
erosion of about 50 feet occurred at this section of Carlsbad Blvd. during the
1983 storm season. A wave runup level of +20.9 feet MLLW was obtained for the
January 1983 storm event, resulting in an excess runup of 4.1 feet. Thus, a
horizontal erosion of 50 feet was related to an excess runup of 4.1 feet. It
39
was assumed that no erosion would occur for excess runups of 3 feet or less.
Also, it was assumed that the road would be totally damaged when an erosion of
150 feet occurred. With an erosion of 150 feet corresponding to an excess
runup of 6.3 feet, erosion was assumed to be constant at 150 feet for excess
runups greater than 6.3 feet. Thus, erosion caused by various runups were
obtained by linear interpolation between the two data points, i.e., 0 feet
erosion at 3 feet excess runup and 150 feet erosion at 6.3 feet excess runup.
Damages were projected for various storm intensities in terms of percent
by reach or structure type, equated to an absolute quantity of materials and
valued by its depreciated replacement cost.
Present and future without project runup levels and storm erosion were
computed for the various return periods. The probability of extreme runup
elevations on the coastal structures were modeled by the statistical
simulation described in Section A-6.3.3. Erosion is based on the discussion
of Section A-6.2.3. The estimation of physical damages and its valuation is
contained in the Economics Appendix.
A-6.5.2 Wave Height - Damage Mechanism
As previously indicated, maximum wave runup elevations provide the force
by which the coastal structures are damaged. Damage criteria for these
elements were developed through inferences made with respect to prior damages
sustained by the structures at the Carlsbad coastal area. Study of historical
damages at other coastal facilities in southern California has provided
insight into the potential performance and consequent vulnerability of
different sections of the Carlsbad coastal area to storm damage, based upon
differing structure types. Detailed information on the structural
capabilities of the coastal structures provided by the design engineer and as-
built drawings has also been incorporated into an overall assessment of
potential storm damage vulnerabilities.
A-6.5.3 Damage Analysis to Coastal Facilities
Projected damages to the coastal facilities for the present and future
without project conditions are presented in Tables 6.6 and 6.7. The damages
to the revetments are shown in Table 6.6. Table 6.7 shows the damages to the
causeway section of Carlsbad Blvd. in Reach 3 between the intake and outlet
jetties of Agua Hedionda Lagoon. Table 6.8 shows the damages to the causeway
section of Carlsbad Blvd. in Reach 5 at which the road elevation is about 18.3
feet MLLW.
40
Table 6.6 Revetment Damages - Present and Future Without Project
Carlsbad - Damage of Revetments
Item 2-year 5-year 10-year 25-year 50-year 100-year 200-year
Present Condition
2445 Ocean 70 LF at $402.86 / ft = $28,200
Hb/H D=0 1.14 1.26 1.3 1.35 1.38 1.41 1.44
Damage(%) 8 14 17 19 21 24 27
Damage $2,300 $3,900 $4,800 $5,400 $5,900 $6,800 $7,600
2505-2643 Ocean 750 LF at $329.20 / ft = $246,900
Hb/H D=0 1.29 1.43 1.48 1.53 1.57 1.6 1.64
Damage(%) 16 26 31 37 41 45 50
Damage $40,000 $64,000 $77,000 $91,000 $101,000 $111,000 $123,000
2723-2751, 2955 Ocean 400 LF at $455.00 / ft = $182,000
Hb/H D=0 1.14 1.26 1.3 1.35 1.38 1.41 1.44
Damage(%) 8 14 17 19 21 24 27
Damage $15,000 $25,000 $31,000 $35,000 $38,000 $44,000 $49,000
North of Intake Jetties 450 LF at $180.00 / ft = $81,000
Hb/H D=0 0.85 1.08 1.24 1.42 1.58 1.7 1.71
Damage(%) 0 5 13 25 43 60 61
Damage $0 $4,000 $11,000 $20,000 $35,000 $49,000 $49,000
South of Intake Jetties 350 LF at $134.29 / ft = $47,000
Hb/H D=0 1.22 1.54 1.78 2.04 2.26 2.43 2.46
Damage(%) 12 38 70 100 100 100 100
Damage $6,000 $18,000 $33,000 $47,000 $47,000 $47,000 $47,000
5001-5115 Tierra Del Oro 1200 LF at $450.00 / ft = $540,000
Hb/H D=0 1.07 1.16 1.22 1.27 1.29 1.32 1.34
Damage(%) 5 9 12 15 16 18 19
Damage $27,000 $49,000 $65,000 $81,000 $86,000 $97,000 $103,000
50-year Future Condition
North of Intake Jetties 450 LF at $180.00 / ft = $81,000
Hb/H D=0 2.06 2.15 2.21 2.26 2.29 2.32 2.35
Damage(%) 100 100 100 100 100 100 100
Damage $81,000 $81,000 $81,000 $81,000 $81,000 $81,000 $81,000
South of Intake Jetties 350 LF at $134.29 / ft = $47,000
Hb/H D=0 2.96 3.08 3.17 3.24 3.28 3.32 3.37
Damage(%) 100 100 100 100 100 100 100
Damage $47,000 $47,000 $47,000 $47,000 $47,000 $47,000 $47,000
41
Table 6.7 Carlsbad Blvd. Reach 3 Damages - Present and Future Without Project
Reach 3 - Carlsbad Blvd. Damage
16.8 ft = road elevation
2,000 ft = length of road damaged
Jan 83 storm, excess runup = 20.9 - 16.8 = 4.1 ft, erosion = 50 ft
Assume excess runup of 3 ft and less causing 0 ft erosion
$6.00 per ft2 = Damage Repair
150 ft = Total Road Erosion
Return
Period (yr)
2
5
10
25
50
100
200
2
5
10
25
50
100
200
Wave
Runup (ft)
Excess
Runup (ft)
(ft) (ft2)
Erosion Area
Present Condition
18.2 1.4 0
19.5
20.4
21.2
21.7
22.2
22.7
50 -year
21.4
22.7
23.5
24.3
24.8
25.4
25.8
2.7
3.6
4.4
4.9
5.4
5.9
0
27
64
86
109
132
0
0
54,000
128,000
172,000
218,000
264,000
($)
Damage
0
0
324,000
768,000
1,032,000
1,308,000
1,584,000
Future Condition
4.6
5.9
6.7
7.5
8.0
8.6
9.0
73
132
150
150
150
150
150
146,000
264,000
300,000
300,000
300,000
300,000
300,000
876,000
1,584,000
1,800,000
1,800,000
1,800,000
1,800,000
1,800,000
42
Table 6.8 Carlsbad Blvd. Reach 5 Damages - Present Without Project
Reach 5 - Carlsbad Blvd. Damage Present Condition
18.3 ft = road elevation
1,000 ft = length of road subject to damaged
Assume excess runup of 3 ft and less causing 0 ft erosion
$6.00 per ft~2 = Damage Repair
100 ft = Total Road Erosion
Return
Period(yr)
2
5
10
25
50
100
200
Wave
Runup (ft)
19
21
22
23
23
24
24
.9
.5
.5
.5
.9
.5
.9
Excess
Runup (ft)
1
3
4
5
5
6
6
.6
.2
.2
.2
.6
.2
.6
(ft) (ft "2
Erosion Area
0
9
55
100
100
100
100
9,
55,
100,
100,
100,
100,
0
000
000
000
000
000
000
($)
Damage
54,
330,
600,
600,
600,
600,
0
000
000
000
000
000
000
43
A-7.0 WITH PROJECT CONDITIONS
A-7.1 Planning Criteria
Alternatives were developed in response to the primary need for storm
damage protection at the project site, as well as to provide an opportunity
for the potential re-establishment of beach activities in the area.
Additional information on the development of these criteria can be found
within the body of the Main report.
A-7.2 Preliminary Basis for Design
The assumptions and basis for design of the alternative plans are
described in the following sections.
A-7.2.1 Beachfill
The width of the berm is 200 feet and its crest elevation is +10 feet
MLLW. The berm crest slopes downward 1 vertical to 20 horizontal to the
natural nearshore bottom. The characteristics of sand from the borrow site
will be compatible with those of the native sand in the Carlsbad coastal area.
According to the boring data obtained by Woodward-Clyde Consultants (1990),
the median grain size of the sand is about 0.2 mm. Based on the typical beach
profiles, the cross-sectional areas of beachfill are about 3,600 ft2 and 3,460
ft2 at Reach 1 and Reach 3, respectively.
To maintain a minimum width of 200 feet for the protective beach, an
extra volume of sand will be required during the initial construction of the
beachfill. The extra volume will account for the sand loss which takes place
between the time interval of replenishment, because there is a net longshore
transport of 270,000 cubic yards per year moving towards the south.
A-7.2.2 Groin
a. Design Water Depth:
Similar to the groins constructed in the coastal area of southern
California, such as Ventura Harbor and Newport Beach, the groins are designed
to terminate in a water depth of -10 feet MLLW. Based on the bathymetry of
the Carlsbad coastal area, this water depth results in a groin length of about
800 feet. According to the CCSTWS conducted by USAED, Los Angeles (1991), the
44
maximum sea level at La Jolla associated with a return period of 1 year is
+6.95 feet MLLW. Thus, the design water depth is 10 + 6.95 = 16.95 feet.
The distance between groins is usually on the order of two to three
groin lengths. Thus, a groin spacing of 2.5 times the groin length or 2,000
feet has been selected.
b. Design Wave Height:
A design wave height associated with a return period of 25 years is used
in this preliminary evaluation to approximate the optimal armor size in
balancing the first and repair costs. From Table 4.2, the significant wave
height of this event is 15.9 feet. Then the maximum waves that can be
sustained near the structure head by a design depth of 16.95 feet are
determined basing on the conditions of wave breaking and wave steepness. A
wave period of 17 seconds and a nearshore slope of 1:51 have been used in the
calculations. According to Weggel (1972), the maximum breaker height is 16.5
feet. According to Miche (1944), the maximum wave height subject to the
limiting steepness is 14.8 feet. Therefore, the design wave height is 14.8
feet.
c. Rock Structural Stability and Section Design:
The groin structures are designed according to the SPM (1984). Armor
sizes are designed using Hudson's formula and a specific gravity Sr of 2.65.
Minimum side slopes of 1 vertical to 2 horizontal are utilized. The number of
units comprising the thickness of the armor layer is 2. The stability
coefficient K^ is 2.5. Rock is assumed to be individually placed, in the
usual stable configuration with the long axis of the stone placed
perpendicular to the structure face. An armor stone weight of 12 tons is
determined for the structure head. Rock gradation of 9 to 15 tons is assumed,
with 50% to be greater than 12 tons. The recommended minimum crest width is 3
stones, resulting in an 16-foot-wide crest utilizing 12-ton stones (assuming
5.3 feet wide per stone). The underlayer or B-l stone is sized as 10% of the
armor stone. This yields a B-l stone size of 1 to 3 tons, with 50 percent
greater than 1 ton. The core stone (C-Stone) is selected as quarry run.
Also, an armor stone weight of 7 tons is determined for the structure trunk.
The groin will be grouted to prevent the longshore sediment from passing
through the structure. Grouting starts from the berm end of the groin to
about 400 feet offshore, along the centerline of the groin. The groin is
grouted from the crest to the MLLW line.
45
A-7.2.3 Offshore Breakwater
a. Design Water Depth:
The offshore breakwater is designed to be located outside of the surf
zone in a water depth of about -11.7 feet MLLW. Thus, the design water depth
is 11.7 + 6.95 = 18.7 feet.
b. Design Wave Height:
A design wave height associated with a return period of 25 years has
been selected. The significant wave height of this event is 15.9 feet. Then
the maximum waves that can be sustained near the structure by a design depth
of 18.7 feet are determined basing on the conditions of wave breaking and wave
steepness. A wave period of 17 seconds and a nearshore slope of 1:51 have
been used in the calculations. According to Weggel (1972), the maximum
breaker height is 18.1 feet. According to Miche (1944), the maximum wave
height subject to the limiting steepness is 16.3 feet. Therefore, the design
wave height is 15.9 feet.
c. Rock Structural Stability and Section Design:
The breakwater structures are designed according to the SPM (1984) .
Armor sizes are designed using Hudson's formula and a specific gravity Sr of
2.65. Minimum side slopes of 1 vertical to 2 horizontal are utilized. The
stability coefficient Kj is 2.3. Rock is assumed to be individually placed,
in the usual stable configuration with the long axis of the stone placed
perpendicular to the structure face. An armor stone weight of 16 tons is
determined for the structure. Rock gradation of 12 to 20 tons is assumed,
with 50% to be greater than 16 tons. The recommended minimum crest width is 3
stones, resulting in an 18-foot-wide crest utilizing 16-ton stones (assuming 6
feet wide per stone). The underlayer or B-2 stone is sized as 10% of the
armor stone. This yields a B-2 stone size of 1 to 3 tons, with 50 percent
greater than 2 tons. The core stone (C-Stone) is selected as quarry run.
A-7.2.4 Revetment
The revetment constructed to protect the 10 structures in Reach 1,
Section 4 is designed to withstand a 25-year storm event. The design water
depths shown in Table 6.3 for Reach 1, Section 4 have been used to calculate
46
the breaking wave heights. It is assumed that the design wave for the
stability of the quarry stone revetment is the maximum wave that breaks
directly on the structure. The following parameters have been used: a design
depth of 9.3 feet, a wave period of 17 seconds, and a nearshore slope of 1:51.
According to Weggel (1972), the maximum breaker height is 9.1 feet. According
to Miche (1944), the maximum wave height subject to the limiting steepness is
8.2 feet. Therefore, the design wave height is 8.2 feet.
The revetment structure in Reach 1, Section 4 has been designed
according to the SPM (1984). Armor sizes are designed using Hudson's formula
and a specific gravity Sr of 2.65. The existing slope of 1 vertical to 1.5
horizontal has been utilized. The stability coefficient Ki is 2.0. Rock is
assumed to be individually placed in the usual stable configuration. An armor
stone weight of 3 tons is determined for the structure. Rock gradation of 2
to 4 tons is assumed, with 50% to be greater than 3 tons. The layer thickness
is 2 stones, resulting in a 7-foot-thick armor layer. The core layer is about
1.5 feet thick and the core stone (C-Stone) is selected as quarry run.
The design of the seawall constructed in Reach 3 is based on the design
of the public seawall constructed by the City of Carlsbad. The seawall
consists of a concrete cap built on a sheet pile wall. Also, toe stones are
placed on the seaward side of the sheet pile wall.
Rubble-mound revetments have also been designed as protective structures
in Reach 3 and Reach 5. The armor stone weights are determined to be 6 tons
for the structure in Reach 3 and 4 tons for the structure in Reach 5.
A-7.3 Description of Alternate Plans
To protect the Carlsbad coastal area from storm damage and to armor the
shoreline against further erosion, the following beach stabilization and
protective structures have been considered: beach nourishment, seawall and
revetment, groin, and offshore breakwater. The plans, which have been
developed as alternative strategies to reduce storm damages along the coastal
area of Carlsbad, are outlined in the following sub-sections.
Other schemes of shoreline stabilization include sand bypassing and
submerged sill. However, these two schemes have not been considered in the
alternative plans.
47
A-7.3.1 Plan 1 - Beachfill in Reaches 1 and 2
As shown in Figure 7.la, a 200-foot berm is constructed at the coastal
area of Reaches 1 and 2. The elevation of the beachfill is +10 feet MLLW and
the length of the beachfill is about 5,000 feet. The beach face slopes
downward approximately 1 vertical on 20 horizontal from the berm crest to the
natural nearshore bottom. Figure 7.Ib shows a typical cross-section of the
beachfill.
A-7.3.2 Plan 2 - A Groin System with Beachfill in Reaches 1 and 2
As shown in Figure 7.2a, a system of three groins are used to stabilize
the beachfill in Reaches 1 and 2. The groins are 600 feet long and 2,000 feet
apart. (Basing on the observation of the historical beach profiles at the
south groin of Oceanside Harbor, the groin length has been reduced from the
original design of 800 feet to 600 feet.) Figure 7.2b shows a typical cross-
section of the groin. The elevation of the beachfill is +10 feet MLLW and the
width of the berm is 200 feet. The beach face slopes downward approximately 1
vertical on 20 horizontal from the berm crest to the natural nearshore bottom.
Figure 7.Ib shows a typical cross-section of the beachfill.
A-7.3.3 Plan 3 - An Offshore Breakwater System in Reaches 1 and 2
As shown in Figure 7.3a, three offshore breakwaters are used to provide
protection from wave action to the shoreline of Reaches 1 and 2. Each
breakwater is 800 feet long and the gap between the breakwaters is 800 feet.
Figure 7.3b shows a typical cross-section of the offshore breakwater. Figure
7.3a also shows the anticipated shoreline change associated with this offshore
breakwater system.
A-7.3.4 Plan 4 - New and Repaired Revetments in Reach 1
As shown in Figure 7.4a, a 600-foot long revetment is built in Reach 1
to protect ten structures from erosion by waves and currents. This revetment
is intended to provide protection to the structures that presently do not have
protective structures. Figure 7.4b shows a typical cross-section of the
rubble-mound revetment. Also, the existing revetments in Reach 1 are repaired
to bring them to the specifications of the new revetment.
48
A-7.3.5 Plan 5 - Beachfill and North Intake Jetty Extension in Reaches
1, 2, and 3
As shown in Figure 7.5, a berm is constructed at the coastal area of
Reaches 1 and 2. The berm is 200 feet wide at the northern end near Buena
Vista Lagoon and is 330 feet wide at the southern end near the north intake
jetty of Agua Hedionda Lagoon. The elevation of the beachfill is +10 feet
MLLW and the length of the beachfill is about 7,400 feet. The beach face
slopes downward approximately 1 vertical on 20 horizontal from the berm crest
to the natural nearshore bottom. The typical cross-section of the beachfill
is similar to that shown in Figure 7.1b. The north intake jetty at Agua
Hedionda Lagoon is extended 400 feet, so that the total length of the jetty is
600 feet. The typical cross-section of the extended jetty is similar to that
shown in Figure 7.2b.
A-7.3.6 Plan 6 - Beachfill in Reach 3
As shown in Figure 7.6a, a 200-foot berm is constructed at the coastal
area of Reach 3. The elevation of the beachfill is +10 feet MLLW and the
length of the beachfill is about 2,700 feet. The beach face slopes downward
approximately 1 vertical on 20 horizontal from the berm crest to the natural
nearshore bottom. Figure 7.6b shows a typical cross-section of the beachfill.
A-7.3.7 Plan 7 - A Groin System with Beachfill in Reach 3
As shown in Figure 7.7a, a system of two groins are used to stabilize
the beachfill in Reach 3. The groins are 350 feet long and 900 feet apart.
Figure 7.7b shows a typical cross-section of the groin. The elevation of the
beachfill is +10 feet MLLW and the width of the berm is 200 feet. The beach
face slopes downward approximately 1 vertical on 20 horizontal from the berm
crest to the natural nearshore bottom. Figure 7.6b shows a typical cross -
section of the beachfill.
A-7.3.8 Plan 8 - An Offshore Breakwater System in Reach 3
As shown in Figure 7.8a, three offshore breakwaters are used to provide
protection from wave action to the shoreline of Reach 3. Each breakwater is
400 feet long and the gap between the breakwaters is 400 feet. Figure 7.8b
shows a typical cross-section of the offshore breakwater. Figure 7.8a also
shows the anticipated shoreline change associated with this offshore
breakwater system.
49
A-7.3.9 Plan 9 - A Seawall in Reach 3
As shown in Figure 7.9a, a 2,700 feet long seawall is built in Reach 3
to protect the portion of Carlsbad Blvd. between in intake and outlet jetties
at Agua Hedionda Lagoon. Figure 7.9b shows a typical cross-section of the
seawall.
A-7.3.10 Plan 10 - A Rubble-Mound Revetment in Reach 3
As shown in Figure 7.10a, a 2,700 feet long rubble-mound revetment is
built in Reach 3 to protect the portion of Carlsbad Blvd. between in intake
and outlet jetties at Agua Hedionda Lagoon. Figure 7.10b shows a typical
cross-section of the revetment.
A-7.3.11 Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3
As shown in Figure 7.11, a 200-foot berm is constructed at the coastal
area of Reaches 1, 2, and 3. The elevation of the beachfill is +10 feet MLLW
and the length of the beachfill is about 7,400 + 2,700 = 10,100 feet. The
beach face slopes downward approximately 1 vertical on 20 horizontal from the
berm crest to the natural nearshore bottom. The typical cross-sections of the
beachfill are shown in Figures 7.1b and 7.6b. The north intake jetty at Agua
Hedionda Lagoon is extended 200 feet, so that the total length of the jetty is
400 feet. The typical cross-section of the extended jetty is similar to that
shown in Figure 7.2b. As shown in Figure 7.11, a system of two groins are
used to stabilize the beachfill in Reach 3. The groins are 350 feet long and
900 feet apart. Figure 7.7b shows a typical cross-section of the groin.
A-7.3.12 Plan 12 - A Rubble-Mound Revetment in Reach 5
As shown in Figure 7.12, a 1,000 feet long rubble-mound revetment is
built in Reach 5 to protect the portion of Carlsbad Blvd. at which the road
elevation is about +18.3 feet MLLW. The typical cross-section of the
revetment is similar to that shown in Figure 7.lOb.
A-7.3.13 Plan 13 - A Groin System with Beachfill in Reach 1
As shown in Figure 7.13, a 200-foot berm is constructed at the coastal
area of Reach 1. The elevation of the beachfill is +10 feet MLLW and the
length of the beachfill is about 4,000 feet. The beach face slopes downward
approximately 1 vertical on 20 horizontal from the berm crest to the natural
50
nearshore bottom. A typical cross-section of the beachfill is shown in Figure
7.1b. Two 400-foot groins are used to stabilize the beachfill. A typical
cross-section of the groin is shown in Figure 7.2b.
A-7.3.14 Plan 14 - A T-Groin with Beachfill in Reach 3
As shown in Figure 7.14, a T-groin is used to stabilize the beachfill in
Reach 3. The beachfill is about 2,700 feet long. The elevation of the
beachfill is +10 feet MLLW and the width of the berm is 200 feet. The beach
face slopes downward approximately 1 vertical on 20 horizontal from the berm
crest to the natural nearshore bottom. A typical cross-section of the
beachfill is shown in Figure 7.6b. The groin is about 350 feet long and the
T-shaped end is about 200 feet long. A typical cross-section of the groin is
shown in Figure 7.7b.
A-7.4 Assessment of Alternate Plans
An assessment of these alternative strategies is described in the
following sub-sections. Included in the assessment are the shoreline
response, wave runup, and damages to coastal structures. For damages to the
coastal structures, the same damage criteria and method of calculation
detailed in Section A-6.5.1 are used.
A-7.4.1 Plan 1 - Beachfill in Reaches 1 and 2
To maintain a minimum width of 200 feet for the protective beach, an
extra volume of sand will be required during the initial construction of the
beachfill. The extra volume will account for the sand loss which takes place
between the time interval of replenishment, because there is a net longshore
transport of 270,000 cubic yards per year. Since there is continuous dredging
at Oceanside Harbor and beach disposal of the dredged materials south of the
harbor, it is assumed that Reaches 1 and 2 will receive 100,000 cubic yards
per year from this sand bypass operation. Thus, the replenishment rate of the
beachfill becomes 170,000 cubic yards per year. Table 7.1 shows an
optimization of the annual cost by using different replenishment frequencies.
The beachfill will be replenished on a 5-year cycle for the case without any
stabilizing structures.
51
Table 7.1 Plan 1 - Beachfill in Reaches 1 and 2 - Analysis of Beachfill
Replenishment Frequency without Groins
3.00 % = Engineering During Construction
8.00 % = Preconstruction Engineering and Design
7.00 % = Construction Management
$3.00 per yd'3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,600 ft'2 x 5,000 ft = 666,667 yd'3
170,000 yd'3 per year = Replenishment Rate
Carlsbad Beachfill - Reach 1 Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD"3) NEW BEACHFILL
NEW ADVANCED NOURISHMENT
TOTAL 1ST TIME QUANTITY
RE -NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
666,
170,
836,
170,
$500,
$2,510,
$3,010,
PRECONSTRUCTION ENGINEER I NG&DES I GN $240,
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE -NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
$210,
$90,
$3,551.
$500,
$510,
$1,010,
PRECONSTRUCTION ENGINEERING & DESIGN$80,
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
$70.
$30,
$1,191,
700
000
700
000
1
000
100
100
800
700
300
900
000
000
000
800
700
300
800
12.23348
$14,579,900
$18,131,800
$1,482,100
666,
340,
1,006,
340,
$500,
$3,020,
$3,520,
$281,
$246,
$105,
$4,153,
$500,
$1,020,
$1,520,
$121,
$106,
$45,
$1,793,
700
000
700
000
2
000
100
100
600
400
600
700
000
000
000
600
400
600
600
5.88148
$10,549,000
$14,702,700
$1,201,800
666,
510,
1,176,
510,
$500,
$3,530,
$4,030,
$322,
$282,
$120,
$4,755,
$500,
$1,530,
$2.030,
$162,
$142,
$60,
$2,395.
700
000
700
000
3
000
100
100
400
100
900
500
000
000
000
400
100
900
400
3.76832
$9,026,600
$13,782,100
$1,126,600
666,
680,
1,346,
680,
$500,
$4,040,
$4,540,
$363,
$317,
$136.
$5.357.
$500,
$2,040,
$2,540,
$203,
700
000
700
000
4
000
100
100
200
800
200
300
000
000
000
200
$177,800
$76,200
$2.997,200
2.71486
$8,137,000
$13,494,300
$1,103,100
666,
850,
1,516,
850,
$500,
$4,550,
$5,050,
$404,
$353,
$151.
$5.959,
$500,
$2,550,
$3,050,
$244,
$213,
$91,
700
000
700
000
5
000
100
100
000
500
500
100
000
000
000
000
500
500
$3,599,000
2.08528
$7,504,900
$13,464,000
$1,100,600
666,700
1,020,000
1,686,700
1,020,000
6
$500,000
$5,060,100
$5,560,100
$444,800
$389,200
$166,800
$6,560,900
$500,000
$3,060,000
$3,560,000
$284,800
$249,200
$106,800
$4,200,800
1.66761
$7.005,300
$13,566,200
$1,108,900
An analysis of the shoreline retreat similar to that described in
Section A-6.2.3 has been performed to estimate the probable berm width for use
in the calculation of wave runup. Since the beaches of Carlsbad do not have
52
enough sand, a location - PN 1080 - north of Oceanside Harbor has been chosen
to analyze the seasonal movement of a sandy beach. The shoreline data are
obtained from the CCSTWS of USAED, Los Angeles (1991) . The MHHW shoreline
retreat associated with return periods of 5, 10, 25, 50, and 100 years are
160, 188, 218, 237, and 255 feet, respectively. The with project beachfill
will have a berm width varying between 200 feet and 400 feet wide, depending
on when in the replenishment cycle the storm occurs. For storms with less
than 200-foot shoreline retreat, the 200 feet wide initial berm width is
assumed to calculate wave runup because the residual damage for these events
will be negligible. For storms with shoreline retreat greater than 200 feet,
the runup can be the same as without project if the protective beach is
narrower than the storm recession. To approximate residual damages with
project beachfill, it is estimated that the return period would double for
events with recession greater than 200 feet or that the 50-year without
project runup would be equivalent to the 100-year with project runup. The
design water depths shown in Table 6.3 and two wave periods, namely 15 and 17
seconds, have been used in the wave runup calculation. The results of wave
runup in Reaches 1 and 2 are shown in Table 7.2 for the with project
condition.
Table 7.2 Carlsbad - Wave Runup Statistics at Reaches 1 & 2 - With Project
Carlsbad Wave Runup Level (ft MLLW)
Line
Rl SI
Rl S2
Rl S3
Rl S4
REACH 2
2-yr
13.7
13.9
13.7
13.7
14.2
5-yr
15.3
15.6
15.2
15.3
15.6
10 -yr
16.1
16.5
16.0
16.2
16.5
2 5-yr
20.8
23.2
20.2
21.1
23.4
50-yr
21.1
23.5
20.5
21.4
23.8
100-yr
21.4
23.8
20.8
21.7
24.2
200-yr
21.9
24.4
21.3
22.2
24.5
Using the results of wave runup, the reduction in damage to ancillary
improvements and flooded structures can be obtained. As shown in Figure 6.8,
bluff erosion will start to occur at an excess wave runup of about 8.6 feet.
Utilizing the assumptions stated in Section A-6.5.1, damages due to bluff
retreat undermining structure foundations will initiate at the 100-year event
while complete structural damages along this unprotected reach occurs at the
200-year event. Since the berm provides protection from wave attack,
structural damage to revetment is reduced as shown in Table 7.3.
53
Table 7.3 Carlsbad Revetment Damages - With Project Conditions
Item 2-year 5-year 10-year 25-year 50-year 100-year 200-year
Results of Plans 1, 2, 5, 11, 13 at 2445 Ocean, 70 LF at $402.86/ft = $28,200
Damage (%) 0 0 0 6 14 21 24
Damage 000 $1,700 $3,900 $5,900 $6,800
Results of Plans 1, 2, 5, 11, 13 at 2505-2643 Ocean, 750 LF at $329.20/ft = $246,900
Damage(%) 0 0 0 12 27 41 45
Damage 000 $30,000 $67,000 $101,000 $111,000
Results of Plans 1,2,5,11,13 at 2723-2751,2955 Ocean, 400 LF at $455.00/ft = $182,000
Damage(%) 0 0 0 6 14 21 24
Damage 000 $11,000 $25,000 $38,000 $44,000
Results of Plans 5, 11 at North of Intake Jetties, 450 LF at $180.00/ft = $81,000
Damage(%) 0 0 0 13 28 43 60
Damage 000 $11,000 $23,000 $35,000 $49,000
Results of Plans 6,7,11,14 at South of Intake Jetties, 350 LF at $134.29/ft = $47,000
Damage(%) 0 0 0 30 65 100 100
Damage 000 $14,000 $31,000 $47,000 $47,000
A-7.4.2 Plan 2 - A Groin System with Beachfill in Reaches 1 and 2
Groin construction will result in the shoreline reorienting itself more
nearly parallel with the prevailing incident wave crests. Net longshore
transport rates along the reoriented shoreline will be lower because the angle
between the average incoming wave crests and the new shoreline will be
smaller. By assuming that the angle is reduced by a factor of two, the
resulting net longshore transport rate will be reduced by about the same
factor for small angles. Thus, a net longshore transport rate of 135,000
cubic yards per year has been assumed. It is also assumed that Reaches 1 and
2 will receive 100,000 cubic yards per year from the sand bypass operation at
Oceanside Harbor. Thus, a beachfill replenishment rate of 35,000 cubic yards
per year has been used in the optimization of the replenishment frequency. As
shown in Table 7.4, the beachfill will be replenished on a 10-year cycle with
a groin system acting as stabilizing structures.
54
Except for a longer project life for the beachfill, the results of wave
runup and damages to coastal structures are the same as those of Plan 1.
A-7.4.3 Plan 3 - An offshore Breakwater System in Reaches 1 and 2
Assuming that there is enough longshore transport, salients will form as
a response to the breakwater system as shown in Figure 7.3a. Behind multiple
breakwaters, Suh and Dalrymple (1987) proposed that the length of the salient
ys can be expressed as:
(7.1)
where y is the distance from the original shoreline to the breakwater, b is
the gap width between the breakwaters, and X is the length of breakwater.
Also, Suh and Dalrymple (1987) suggested that tombolo formation will be
precluded if:
(7.2)y
As mentioned in Section A-7.2.3, the breakwaters are located in a water depth
of -11.8 feet MLLW. With the nearshore bathymetry, the distance y is about
900 feet. With a breakwater length of 600 feet and a gap width of 800 feet,
the formation of tombolo will be precluded according to Equation 7.2. Using
Equation 7.1, the length of the salient is about 490 feet.
Assuming that the breakwater system will effectively control erosion and
retain sand on the beach, the salients will provide better protection to the
coastal structures than the beachfill and groin systems. Thus, damages due to
wave runup and wave action will reduce to a minimum.
55
Table 7.4a Plan 2 - A Groin System with Beachfill in Reaches 1 and 2 -
Analysis of Beachfill Replenishment Frequency
3.00 % = Engineering During Construction
8.00 % = Preconstruction Engineering and Design
7.00 % = Construction Management
$3.00 per yd3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,600 ft2 x 5,000 ft = 666,667 yd3
35,000 yd3 per year = Replenishment Rate
Carlsbad Beachfill - Reach 1 - Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD"3) NEW BEACHFILL
NEW ADVANCED NOURISHMENT
TOTAL 1ST TIME QUANTITY
RE -NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE-NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
666,700
35,000
701,700
35,000
1
$500,000
$2,105,100
$2,605,100
$208,400
$182,400
$78,200
$3,074,100
$500,000
$105,000
$605,000
PRECONSTRUCTION ENGINEERING & DESIGN$48,400
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
$42,400
$18,200
$714,000
12.23348
$8,734,700
666,700
70,000
736,700
70,000
2
$500,000
$2,210,100
$2,710,100
$216,800
$189,700
$81 ,300
$3,197,900
$500,000
$210,000
$710,000
$56,800
$49,700
$21,300
$837,800
5.88148
$4,927,500
666,700
105,000
771,700
105,000
3
$500,000
$2,315,100
$2,815,100
$225,200
$197,100
$84,500
$3,321,900
$500,000
$315,000
$815,000
$65,200
$57,100
$24,500
$961,800
3.76832
$3,624,400
666,700
140,000
806,700
140,000
4
$500,000
$2,420,100
$2,920,100
$233,600
$204,400
$87,600
$3,445,700
$500,000
$420,000
$920,000
$73,600
$64,400
$27,600
$1,085,600
2.71486
$2,947,300
666,700
175,000
841,700
175,000
5
$500,000
$2,525,100
$3,025,100
$242,000
$211,800
$90,800
$3,569,700
$500,000
$525,000
$1,025,000
$82,000
$71,800
$30,800
$1,209,600
2.08528
$2,522,400
666,700
210,000
876,700
210,000
6
$500,000
$2,630,100
$3,130,100
$250,400
$219,100
$93,900
$3,693,500
$500,000
$630,000
$1,130,000
$90,400
$79,100
$33,900
$1,333,400
1 .66761
$2,223,600
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
$11,808,800 $8,125,400 $6,946,300 $6,393,000 $6,092,100 $5,917,100
$965,300 $664,200 $567,800 $522,600 $498,000 $483,700
56
Table 7.4b Plan 2 - A Groin' System with Beachfill in Reaches 1 and 2
Analysis of Beachfill Replenishment Frequency
3.00 % = Engineering During Construction
8.00 % = Reconstruction Engineering and Design
7.00 X = Construction Management
$3.00 per yd3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,600 ft2 x 5,000 ft = 666,667 yd3
35,000 yd3 per year = Replenishment Rate
Carlsbad Beachfill - Reach 1 - Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD'3) NEW BEACHFILL
NEW ADVANCED NOURISHMENT
TOTAL 1ST TIME QUANTITY
RE-NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE -NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
666,700
245,000
911,700
245,000
7
$500,000
$2,735,100
$3,235,100
$258,800
$226,500
$97,100
$3,817,500
$500,000
$735,000
$1,235,000
PRECONSTRUCTION ENGINEERING & DESIGN$98,800
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
$86,500
$37,100
$1,457,400
1.37104
$1,998,100
666,700
280,000
946,700
280,000
8
$500,000
$2,840,100
$3,340,100
$267,200
$233,800
$100,200
$3,941,300
$500,000
$840,000
$1,340,000
$107,200
$93,800
$40,200
$1,581,200
1.15013
$1,818,600
666,700
315,000
981,700
315,000
9
$500,000
$2,945,100
$3,445,100
$275,600
$241,200
$103,400
$4,065,300
$500,000
$945,000
$1,445,000
$115,600
$101,200
$43,400
$1,705,200
0.97965
$1,670,500
666,700
350,000
1,016,700
350,000
10
$500,000
$3,050,100
$3.550,100
$284,000
$248,500
$106,500
$4,189,100
$500,000
$1,050,000
$1,550,000
$124,000
$108,500
$46,500
$1,829,000
0.84447
$1,544,500
666,700
385,000
1,051,700
385,000
11
$500,000
$3,155,100
$3,655,100
$292,400
$255,900
$109,700
$4,313,100
$500,000
$1,155,000
$1,655,000
$132,400
$115,900
$49,700
$1,953,000
0.73494
$1,435,300
666,700
420,000
1,086,700
420,000
12
$500,000
$3,260,100
$3,760,100
$300,800
$263,200
$112,800
$4,436,900
$500,000
$1,260,000
$1,760,000
$140,800
$123,200
$52,800
$2,076,800
0.64464
$1,338,800
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
$5,815,600 $5,759,900 $5,735,800 $5,733,600 $5,748,400 $5,775,700
$475,400 $470,800 $468,900 $468,700 $469,900 $472,100
57
A-7.4.4 Plan 4 - New and Repaired Revetments in Reach 1
Construction of the new revetment and repair to the existing revetments
at Reach 1 is anticipated to cause minimal effects to the existing sediment
transport mechanism, because the toes of the revetment are located at a
landward setback distance. Thus, there will be no adverse impact to the local
coastal processes.
The results of wave runup within Reach 1 will be similar to those of the
without project conditions. Thus, there will be no reduction in damage due to
flooding to the coastal structures in Reach 1. Since the toe of the bluff is
properly protected, structural damage due to bluff retreat is reduced to a
minimum.
Since the new revetment and the repaired revetments have been designed
to withstand a 25-year event, structural damage to the revetments will start
for events associated with return periods greater than 25 years. The
revetment will experience 1.25 %, 2.50 %, and 4.38 % damage associated with
the 50-, 100-, and 200-year events, respectively. Thus, the damages to the
revetments are negligible.
A-7.4.5 Plan 5 - Beachfill and North Intake Jetty Extension in Reaches
1, 2, and 3
Extension of the north intake jetty will result in the shoreline
reorienting itself more nearly parallel with the prevailing incident wave
crests. Net longshore transport rates along the reoriented shoreline will be
lower because the angle between the average incoming wave crests and the new
shoreline will be smaller. By assuming that the angle is reduced by a factor
of two, the resulting net longshore transport rate will be reduced by about
the same factor for small angles. Thus, a net longshore transport rate of
135,000 cubic yards per year has been assumed. It is also assumed that
Reaches 1 and 2 will receive 100,000 cubic yards per year from the sand bypass
operation at Oceanside Harbor. Since there are continuous dredging of about
120,000 cubic yards per year at Agua Hedionda Lagoon and beach disposal of the
dredged materials north and south of the lagoon, it is further assumed that
Reach 2 will receive 60,000 cubic yards per year from this sand bypass
operation. Moreover, it is assumed that there is an offshore loss rate of
25,000 cubic yards per year. Thus, beachfill replenishment is not required
for this plan. Based on the typical cross-sectional area of 4,560 ft2, the
volume of beachfill (1,249,800 cubic yards) is estimated by using the
pertaining length of 7,400 feet.
58
The results of wave runup and damages to the coastal structures are the
same as those of Plan 1, except for the revetment situated north of the north
intake jetty. Structural damage to this revetment is reduced as shown in
Table 7.3.
A-7.4.6 Plan 6 - Beachfill in Reach 3
Since there are continuous dredging of about 120,000 to 130,000 cubic
yards per year at Agua Hedionda Lagoon and beach disposal of the dredged
materials north and south of the lagoon, it is assumed that Reach 3 will
receive 60,000 cubic yards per year from this sand bypass operation. Thus,
the replenishment rate of the beachfill becomes 210,000 cubic yards per year.
The optimum time interval of beachfill replenishment is analyzed as shown in
Table 7.5. Without any stabilizing structure, the beachfill in Reach 3 will
be replenished on a 4-year cycle. Also, the procedure described in Section A-
7.4.1 has been used in the wave runup calculation. The results of wave runup
in Reach 3 are +14.9, +16.2, +17.0, +21.0, +21.3, +21.7, +22.2 feet MLLW
associated with return periods of 2-, 5-, 10-, 25-, 50-, 100-, and 200-year,
respectively.
Using the results of wave runup, damages to the causeway section of
Carlsbad Blvd. between the intake and outlet jetties of Agua Hedionda Lagoon
can be obtained. Based on the road elevation of +16.8 feet MLLW, the results
of excess runup are 0.2, 4.2, 4.5, 4.9, and 5.4 feet associated with return
periods of 10-, 25-, 50-, 100-, and 200-year, respectively. Table 7.6 shows
the results of wave runup and damages to Carlsbad Blvd. for the with project
condition.
Since the bertn provides protection from wave attack, damage to revetment
is reduced and is shown in Table 7.3.
59
Table 7.5 Plan 6 - Beachfill in Reach 3
Replenishment Frequency without Groins
- Analysis of Beachfill
3.00 % = Engineering During Construction
8.00 % = Reconstruction Engineering and Design
7.00 % = Construction Management
$3.00 per yd3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,460 ft2 x 2,700 ft = 346,000 yd3
210,000 yd3 per year = Replenishment Rate
Carlsbad Beachfill - Reach 3 Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD"3) NEW BEACHFILL 346,000
NEW ADVANCED NOURISHMENT 210,000
TOTAL 1ST TIME QUANTITY
RE-NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE-NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
556,000
210,000
1
$500,000
$1,668,000
$2,168,000
$173,400
$151,800
$65,000
$2,558,200
$500,000
$630,000
$1,130,000
$90,400
$79,100
$33,900
$1,333,400
12.23348
$16,312,100
346,000
420,000
766,000
420,000
2
$500,000
$2,298,000
$2,798,000
$223,800
$195,900
$83,900
$3,301,600
$500,000
$1,260,000
$1,760,000
$140,800
$123,200
$52,800
$2,076,800
5.88148
$12,214,700
346,000
630,000
976,000
630,000
3
$500,000
$2,928,000
$3,428,000
$274,200
$240,000
$102,800
$4,045,000
$500,000
$1,890,000
$2,390,000
$191,200
$167,300
$71,700
$2,820,200
3.76832
$10,627,400
346,000
840,000
1,186,000
840,000
4
$500,000
$3,558,000
$4,058,000
$324,600
$284,100
$121,700
$4,788,400
$500,000
$2,520,000
$3,020,000
$241,600
$211,400
$90,600
$3,563,600
2.71486
$9,674,700
346,000
1,050,000
1,396,000
1,050,000
5
$500,000
$4,188,000
$4,688,000
$375,000
$328,200
$140,600
$5,531,800
$500,000
$3,150,000
$3,650,000
$292,000
$255,500
$109,500
$4,307,000
2.08528
$8,981,300
346,000
1,260,000
1,606,000
1,260,000
6
$500,000
$4,818,000
$5,318,000
$425,400
$372,300
$159,500
$6,275,200
$500,000
$3,780,000
$4,280,000
$342,400
$299,600
$128,400
$5,050,400
1.66761
$8,422,100
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
$18,870,300 $15,516,300 $14,672,400 $14,463,100 $14,513,100 $14,697,300
$1,542,500 $1,268,300 $1,199,400 $1,182,300 $1,186,300 $1,201,400
60
Table 7.6 Carlsbad Reach 3 - Road Damage with Project Beachfill
Reach 3 - Carlsbad Blvd. Damage - With Project Condition
16.8 ft = road elevation
2,000 ft = length of road damaged
Jan 83 storm, excess runup = 20.9 - 16.8 = 4.1 ft, erosion = 50 ft
Assume excess runup of 3 ft and less causing 0 ft erosion
$6.00 per ft"2 = Damage Repair
150 ft = Total Road Erosion
Return
Period (yr)
2
5
10
25
50
100
200
Wave Excess
Runup ( f t ) Runup ( ft )
14
16
17
21
21
21
22
.9
.2
.0
.0
.3
.7
.2
0
0
0
4
4
4
5
.2
.2
.5
.9
.4
(ft)
Erosion
0
0
0
55
68
86
109
(ft"2)
Area
0
0
0
110,000
136,000
172,000
218,000
($)
Damage
0
0
0
660,000
816,000
1,032,000
1,308,000
A-7.4.7 Plan 7 - A Groin System with Beachfill in Reach 3
Due to the reorientation of the shoreline after groin construction, the
angle between the shoreline and the incoming wave crests will be reduced. The
net longshore transport rate is assumed to be about 130,000 cubic yards per
year. It is also assumed that Reach 3 will receive about 130,000 cubic yards
per year from the sand bypass operation at Agua Hedionda Lagoon. Thus, no
beachfill replenishment is required.
The results of wave runup and damages to coastal structures will be the
same as those of Plan 6.
A-7.4.8 Plan 8 - An Offshore Breakwater System in Reach 3
Assuming that there is enough longshore transport, salients will form as
a response to the breakwaters as shown in Figure 7.7a. As mentioned in
Section A-7.2.3, the breakwaters are located in a water depth of -11.8 feet
MLLW. With the nearshore bathymetry, the distance y is about 900 feet. With
61
a breakwater length of 400 feet and a gap width of 400 feet, the formation of
tombolo will be precluded. Using'Equation 7.1, the length of the salient is
about 430 feet.
Assuming that the breakwater system will effectively control erosion and
retain sand on the beach, the salients will provide better protection to the
coastal structures than the beachfill and groin systems. Thus, damages due to
wave runup and wave action will reduce to a minimum, except for the revetment
located north of the intake jetties since the revetment is located outside of
the breakwater's shadow.
A-7.4.9 Plan 9 - A Seawall in Reach 3
Construction of a seawall at Reach 3, is anticipated to cause minimal
effects to the existing sediment transport mechanism, because the toe of the
seawall is located at a landward setback distance. Thus, there will be no
adverse impact to the local coastal processes.
The results of wave runup within Reach 3 will be similar to those of the
without project conditions. There will be no reduction in damage to the
existing revetments situated north of the intake jetties, because the seawall
is designed to protect the causeway section of Carlsbad Blvd. between the
intake and outlet jetties of Agua Hedionda Lagoon. Thus, the causeway will
not be damaged by wave action. Since the seawall is properly designed against
wave attack, structure damage to seawall is also assumed to be minimal.
A-7.4.10 Plan 10 - A Rubble-Mound Revetment in Reach 3
Construction of a rubble-mound revetment at Reach 3 is anticipated to
have similar effects as construction of the seawall described in Plan 9.
A-7.4.11 Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3
Extension of the north intake jetty will result in the shoreline
reorienting itself more nearly parallel with the prevailing incident wave
crests. Net longshore transport rates along the reoriented shoreline will be
lower because the angle between the average incoming wave crests and the new
shoreline will be smaller. Thus, a net longshore transport rate of 200,000
cubic yards per year has been assumed. It is also assumed that Reaches 1 and
2 will receive 100,000 cubic yards per year from the sand bypass operation at
Oceanside Harbor. Thus, a beachfill replenishment rate of 100,000 cubic yards
62
per year has been used in the optimization of replenishment frequency. As
shown in Table 7.7, the beachfill will be replenished on a 6-year cycle. The
results of storm damage will be similar to those of Plans 1, 2, 5, 6, and 7.
A-7.4.12 Plan 12 - A Rubble-Mound Revetment in Reach 5
Construction of a rubble-mound revetment at Reach 5 is anticipated to
have similar effects as construction of the seawall described in Plan 9.
A-7.4.13 Plan 13 - A Groin System with Beachfill in Reach 1
Construction of the two end groins will result in the shoreline
reorienting itself more nearly parallel with the prevailing incident wave
crests. Net longshore transport rates along the reoriented shoreline will be
lower because the angle between the average incoming wave crests and the new
shoreline will be smaller. Thus, a net longshore transport rate of 135,000
cubic yards per year has been assumed. It is also assumed that Reach 1 will
receive 100,000 cubic yards per year from the sand bypass operation at
Oceanside Harbor. Since there are continuous dredging of about 120,000 cubic
yards per year at Agua Hedionda Lagoon and beach disposal of the dredged
materials north and south of the lagoon, it is further assumed that Reach 1
will receive 60,000 cubic yards per year from this sand bypass operation.
Moreover, it is assumed that there is an offshore loss rate of 25,000 cubic
yards per year. Thus, beachfill replenishment is not required for this plan.
The results of wave runup and damages to the coastal structures are the
same as those of Plan 1. Structural damage to this revetment is reduced as
shown in Table 7.3.
A-7.4.14 Plan 14 - A T-Groin with Beachfill in Reach 3
Due to the reorientation of the shoreline after groin construction, the
angle between the shoreline and the incoming wave crests will be reduced. The
net longshore transport rate is assumed to be about 130,000 cubic yards per
year. It is also assumed that Reach 3 will receive about 130,000 cubic yards
per year from the sand bypass operation at Agua Hedionda Lagoon. Thus, no
beachfill replenishment is required.
The results of wave runup and damages to coastal structures will be the
same as those of Plan 6.
63
Table 7.7a Plan 11 - Beachfill and Structures in Reaches l, 2, and 3
Analysis of Beachfill Replenishment Frequency
3.00 % = Engineering During Construction
8.00 % = Reconstruction Engineering and Design
7.00 X = Construction Management
$3.00 per yd3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,560 ft2 x 10,100 ft = 1,331,704 yd3
100,000 yd3 per year = Replenishment Rate
Carlsbad Beachfill -
Reach 1, Reach 2, and Reach 3 Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD'3) NEW BEACHFILL 1,331,700
NEW ADVANCED NOURISHMENT 100,000
TOTAL 1ST TIME QUANTITY
RE-NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE -NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
1,431,700
100,000
1
$500,000
$4,295,100
$4,795,100
$383,600
$335,700
$143,900
$5,658,300
$500,000
$300,000
$800,000
$64,000
$56,000
$24,000
$944,000
12.23348
$11,548,400
1,331,700
200,000
1,531,700
200,000
2
$500,000
$4,595,100
$5,095,100
$407,600
$356,700
$152,900
$6,012,300
$500,000
$600,000
$1,100,000
$88,000
$77,000
$33,000
$1,298,000
5.88148
$7,634,200
1.331,700
300,000
1,631,700
300,000
3
$500,000
$4,895,100
$5,395,100
$431,600
$377,700
$161,900
$6,366,300
$500,000
$900,000
$1,400,000
$112,000
$98,000
$42,000
$1,652,000
3.76832
$6,225,300
1,331,700
400,000
1,731,700
400,000
4
$500,000
$5,195,100
$5,695,100
$455,600
$398,700
$170,900
$6,720,300
$500,000
$1,200,000
$1,700,000
$136,000
$119,000
$51,000
$2,006,000
2.71486
$5,446,000
1,331,700
500,000
1,831,700
500,000
5
$500,000
$5,495,100
$5,995,100
$479,600
$419,700
$179,900
$7,074,300
$500,000
$1,500,000
$2,000,000
$160,000
$140,000
$60,000
$2,360,000
2.08528
$4,921,300
1,331,700
600,000
1,931,700
600,000
6
$500,000
$5,795,100
$6,295,100
$503,600
$440,700
$188,900
$7,428,300
$500,000
$1,800,000
$2,300,000
$184,000
$161,000
$69,000
$2,714,000
1 .66761
$4,525,900
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
$17,206,700 $13,646,500 $12,591,600 $12,166,300 $11,995,600 $11,954,200
$1,406,500 $1,115,500 $1,029,300 $994,500 $980,600 $977,200
64
Table 7.7b Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3
Beachfill Replenishment Frequency Analysis
3.00 % = Engineering During Construction
8.00 % = Reconstruction Engineering and Design
7.00 % = Construction Management
$3.00 per yd3 of Sand
$500,000 = Mobilization and Demobilization
8.00 % = Interest Rate
50.00 years = Project Life
3,560 ft2 x 10,100 ft = 1,331,704 yd3
100,000 yd3 per year = Replenishment Rate
Carlsbad Beachfill -
Reach 1, Reach 2, and Reach 3 Average Annual Cost of Frequency Alternatives - Sensitivity Analysis
QUANTITY (YD'3) NEW BEACHFILL 1,331,
NEW ADVANCED NOURISHMENT 700,
TOTAL 1ST TIME QUANTITY
RE-NOURISHMENT
FREQUENCY (YEARS)
FIRST COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL FIRST COST OF CONSTRUCTION
RE -NOURISHMENT COSTS :
MOBILIZATION & DEMOBILIZATION
BEACHFILL
SUBTOTAL
PRECON. ENGINEERING & DESIGN
CONSTRUCTION MANAGEMENT
ENGINEERING DURING CONSTRUCTION
TOTAL COST
PRESENT WORTH FACTOR
PRESENT WORTH COSTS
TOTAL PRESENT WORTH COSTS
AVERAGE ANNUAL COST
2,031,
700,
$500,
$6,095,
$6,595,
$527,
$461,
$197,
$7,782,
$500,
$2,100,
$2,600,
$208,
$182,
$78,
$3,068,
700
000
700
000
7
000
100
100
600
700
900
300
000
000
000
000
000
000
000
1.37104
$4,206,
$11,988,
$980,
300
600
000
1,331,
800,
2,131,
800,
$500,
$6.395,
$6,895,
$551,
$482,
$206,
$8,136,
$500,
$2,400,
$2,900,
$232,
$203,
$87,
$3,422,
700
000
700
000
8
000
100
100
600
700
900
300
000
000
000
000
000
000
000
1.15013
$3,935,
$12,072,
$986,
700
000
800
1,331
900
2,231
900
$500
$6,695
$7,195
$575
$503
$215
$8,490
$500
$2,700
$3,200
$256
$224
$96
$3,776
,700
,000
,700
,000
9
,000
,100
,100
,600
,700
,900
,300
,000
,000
,000
,000
,000
,000
,000
0.97965
$3,699
$12,189
$996
,200
,500
,400
1,331,
1,000,
2,331.
1,000,
$500,
$6,995,
$7,495,
$599,
$524,
$224,
$8,844,
$500,
$3,000,
$3,500.
$280,
$245,
$105,
$4.130,
700
000
700
000
10
000
100
100
600
700
900
300
000
000
000
000
000
000
000
0.84447
$3,487,
$12,332,
$1,008,
700
000
100
1,331,
1,100,
2,431,
1,100,
$500,
$7.295,
$7,795,
$623,
$545,
$233,
$9,198,
$500,
$3,300,
$3,800,
$304,
$266,
$114,
$4,484,
700
000
700
000
11
000
100
100
600
700
900
300
000
000
000
000
000
000
000
0.73494
$3,295,
$12,493,
$1,021,
500
800
300
1,331,700
1,200,000
2,531,700
1,200,000
12
$500,000
$7,595,100
$8,095,100
$647,600
$566,700
$242,900
$9,552,300
$500,000
$3,600,000
$4,100,000
$328,000
$287,000
$123,000
$4,838,000
0.64464
$3,118,800
$12,671,100
$1,035,800
65
A-7.5 Preliminary Costs of Construction and Maintenance
Costs to construct the alternatives are calculated and the results are
shown in Tables 7.8 through 7.21. The procedures of calculation are shown in
the following sub-sections. Table 7.22 shows a summary of the annual cost
estimates of the alternative plans. An interest rate of 8% and a project life
of 50 years have been used in calculating the annual cost.
A-7.5.1 Rock and Beachfill Unit-Prices
The cost estimates assume current rock and beachfill unit-prices as
follows:
1. A-16 stone $56/ton
2. A-12 stone $50/ton
3. A-7 stone $45/ton
4. B-2 stone $42/ton
5. B-l stone $35/ton
6. C stone $30/ton for groins; $26/ton for breakwaters
7. Beachfill $3/cubic yard
8. Mobilization for Beachfill $500,000 lump sum
9. Planning, Engineering, and Design: 8% of total construction cost
10. Construction Management: 7% of total construction cost
11. Engineering during Construction: 3% of total construction cost
To account for the uncertainties of estimating the unit-prices and
construction quantities, a contingency of 25% has been applied to the
calculation of cost items.
A-7.5.2 Construction Materials, Quantities, and Costs
The characteristics of sand from the borrow site will be compatible with
those of the native sand in the Carlsbad coastal area. Based on the typical
cross-sectional area, the volume of beachfill is estimated by using the
pertaining lengths of each coastal reach and the frequency of sand
replenishment. Thus, the initial construction includes the volume of sand for
a 200-foot berm and the volume of sand to meet the required replenishment
frequency.
All structures would be constructed with quarry stone of Sr = 2.65, and
meeting standard SPL criteria. It is assumed that the rock structures would
be constructed with land based or floating equipment, typically including a
66
150-ton, barge-mounted crane, various tugs, rock barges etc.
The quantities estimated for the various structures have been calculated
with an in-place rubble-mound density of 1.5 tons per cubic yard of volume.
The quantity estimates are included in Tables 7.8 through 7.21.
A- 7.5.3 Maintenance Requirements
For the beachfill materials, replenishment of the design volume would be
a continuing cost of construction at the replenishment frequency.
For the groins and breakwaters, maintenance requirements would include
the repair and replacement of the rubble-mound structure. From a very
preliminary cost standpoint, it is assumed at this stage of the analysis that
annual maintenance of the rubble-mound structure would run about 0.5 % of the
total first cost of rock placement. In actuality, this maintenance would be
performed on an as-needed basis, resulting in less frequent maintenance
efforts.
67
Table 7.8 Plan 1 - Beachfill in Reaches 1 and 2 - Cost Estimate
Item Quantity Unit Price
Mobilization & 1 Job L.S.
Demobilization
Beachfill 1,516,700 cu yd $3.00
Subtotal Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Present Worth of Beachfill Replenishment (O&M)
Annual Cost of Beachfill Replenishment (O&M)
Cont i ngency
$500,000
$4,550,100
$5,050,100
$404,000
$151,500
$353,500
$5,959,100
$487,100
$7,504,900
$613,500
Cont i ngency
Amount %
$125,000 25
$1,137,500 25
$1,262,500
$101,000 25
$37,900 25
$88,400 25
$1,489,800
$121,800
$1,876,200 25
$153,300
Contingency
$625,000
$5,687,600
$6,312,600
$505,000
$189,400
$441,900
$7,448,900
$608,900
$9,381,100
$766,800
Total Annual Cost $1,100,600 $275,100 $1,375,700
Note: Replenishment = 5-year Cycle at 170,000 ydVyear
(See Table 7.1 for sensitivity analysis of replenishment cycle)
68
Table 7.9 Plan 2 - A Groin System
Estimate
1 Ini t-urn L
Item Quantity Unit Price
600 ft groin:
A-12 Stone 4,800 tons $50.00
A-7 Stone 4,800 tons $45.00
B-1 Stone 9,600 tons $35.00
C-Stone 9,600 tons $30.00
Excavation 25,000 cu yd $6.50
Backfill 15,000 cu yd $6.50
Grouting 1 Job L.S.
Cost of each groin
Cost of 3 groins
Subtotal of Construction Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Cost of Groins
Cost of Initial Beachfill
Total First Cost of Construction
Annual Cost
Present Worth of Beachfill Replenishment
Annual Cost of Beachfill Replenishment
Annual O&M Cost of Groins
Total Annual Cost
with Beachfill in Reaches 1 and 2 - Cost
Cost wi thout
Cont i ngency
$240,000
$216,000
$336,000
$288,000
$162,500
$97,500
$100,000
$1,440,000
$4,320,000
$4,320,000
$345,600
$129,600
$302,400
$5,097,600
$4,189,100
$9,286,700
$759,100
$1,544,500
$126,300
$25,500
$910,900
Cont i ngency
Amount %
$60,000 25
$54,000 25
$84,000 25
$72,000 25
$40,600 25
$24,400 25
$25,000 25
$360,000
$1,080,000
$1,080,000
$86,400 25
$32,400 25
$75,600 25
$1,274,400
$1,047,300 25
$2,321,700
$189,800
$386,100 25
$31,500
$6,400
$227,700
Cost with
Contingency
$300,000
$270,000
$420,000
$360,000
$203,100
$121,900
$125,000
$1,800,000
$5,400,000
$5,400,000
$432,000
$162,000
$378,000
$6,372,000
$5,236,400
$11,608,400
$948,900
$1,930,600
$157,800
$31,900
$1,138,600
Note: Replenishment = 10-year Cycle at 35,000 yd~3/year
(See Table 7.4 for sensitivity analysis of replenishment cycle)
69
Table 7.10 Plan 3 - An Offshore Breakwater System in Reaches 1 and 2 - Cost
Estimate
800-ft Offshore Breakwater:
Item Quantity Unit
Unit Cost without
Price Contingency
Cont i ngency
Amount %
Cost of each breakwater
Cost of 3 breakwaters
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost of Breakwaters
Total Annual Cost
$9,908,800
$29,726,400
$2,378,100
$891,800
$2,080,800
$35,077,100
$2,867,300
$175,400
$3,042,700
$2,477,200
$7,431,600
$594,500 25
$223,000 25
$520,200 25
$8,769,300
$716,800
$43,800
$760,600
Cost with
Cont i ngency
A- 16 Stone
B-2 Stone
C-Stone
93,600
61,600
80,000
tons
tons
tons
$56.00
$42.00
$26.00
$5,241,600
$2,587,200
$2,080,000
$1,310,400
$646,800
$520,000
25
25
25
$6,552,000
$3,234,000
$2,600,000
$12,386,000
$37,158,000
$2,972,600
$1,114,800
$2,601,000
$43,846,400
$3,584,100
$219,200
$3,803,300
70
Table 7.11 Plan 4 - New and Repaired Revetments in Reach 1 - Cost Estimate
Item Quantity Unit Price
A-3 Stone 14,060 tons $43.00
C- Stone 5,230 tons $30.00
Subtotal Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost
Total Annual Cost
Contingency
$604,600
$156,900
$761,500
$60,900
$22,800
$53,300
$898,500
$73,400
$4,500
$77,900
Contingency
Amount %
$302,300 50
$78,500 50
$380,800
$30,500 50
$11,400 50
$26,700 50
$449,400
$36,800
$2,200
$39,000
Cost with
Contingency
$906,900
$235,400
$1,142,300
$91,400
$34,200
$80,000
$1,347,900
$110,200
$6,700
$116,900
Note: 50 X contingency includes resetting cost of existing stones.
71
Table 7.12 Plan 5 - Beachfill and North Intake Jetty Extension in Reaches 1,
2, and 3 - Cost Estimate
Item Quantity
400 ft north intake jetty
A-12 Stone 3,200
A-7 Stone 3,200
B-1 Stone 6,400
C-Stone 6,400
Grouting 1
Cost of Jetty Extension
Beachfill 1,249,800
Mobilization & Demob. 1
Cost of Beachfill
Subtotal of Construction Cost
Unit
Unit Price
extension
tons $50.00
tons $45.00
tons $35.00
tons $30.00
Job US.
cu yd $3.00
Job L. S.
8 X Planning, Engineering, and Design
3 X Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost of Jetty
Total Annual Cost
Cost without
Cont i ngency
$160,000
$144,000
$224,000
$192,000
$100,000
$820,000
$3,749,400
$500,000
$4,249,400
$5,069,400
$405,600
$152,100
$354,900
$5,982,000
$489,000
$4,800
$493,800
Cont i ngency
Amount %
$40,000 25
$36,000 25
$56,000 25
$48,000 25
$25,000 25
$205,000
$937,400 25
$125,000 25
$1,062,400
$1,267,400
$101,400 25
$38,000 25
$88,700 25
$1,495,500
$122,200
$1,200
$123,400
Cost with
Cont i ngency
$200,000
$180,000
$280,000
$240,000
$125,000
$1,025,000
$4,686,800
$625,000
$5,311,800
$6,336,800
$507,000
$190,100
$443,600
$7,477,500
$611,200
$6,000
$617,200
Note: Replenishment = 0
72
Table 7.13 Plan 6 - Beachfill in Reach 3 - Cost Estimate
Item Quantity Unit Price
Mobilization & 1 Job U.S.
Demobilization
Beachfill 1,186,000 cu yd $3.00
Subtotal Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Present Worth of Beachfill Replenishment
Annual Cost of Beachfill Replenishment (O&M)
Contingency
$500,000
$3,558,000
$4,058,000
$324,600
$121,700
$284,100
$4,788,400
$391,400
$9,674,700
$790,800
Cont i ngency
Amount %
$125,000 25
$889,500 25
$1,014,500
$81,200 25
$30,400 25
$71,000 25
$1,197,100
$97,900
$2,418,700 25
$197,700
Contingency
$625,000
$4,447,500
$5,072,500
$405,800
$152,100
$355,100
$5,985,500
$489,300
$12,093,400
$988,500
Total Annual Cost $1,182,200 $295,600 $1,477,800
Note: Replenishment = 4-year Cycle at 210,000 ydVyear
(See Table 7.5 for sensitivity analysis of replenishment cycle)
73
Table 7.14 Plan 7 - A Groin System with Beachfill in Reach 3 - Cost
Estimate
Item
350 ft groin:
A- 12 Stone
A-7 Stone
B-1 Stone
C-Stone
Excavation
Grouting
Cost of each groin
Cost of 2 groins
Beachfill
Quantity
2,800
2,800
5,600
5,600
10,000
1
346,000
Mobilization & Demob. 1
Cost of Beachfill
Subtotal of Construction Cost
8 % Planning, Engineering,
3 % Engineering
Unit Cost without
Unit Price Contingency
tons $50.00
tons $45.00
tons $35.00
tons $30.00
cu yd $6.50
Job L.S.
cu yd $3.00
Job L.S.
(Beachfill + Groins)
and Design
during Construction
7 % Construction Management
Total First Cost of
Annual Cost
Annual O&M Cost of
Total Annual Cost
Construction
Groins
$140,000
$126,000
$196,000
$168,000
$65,000
$100,000
$795,000
$1,590,000
$1,038,000
$500,000
$1,538,000
$3,128,000
$250,200
$93,800
$219,000
$3,691,000
$301,700
$9,400
$311,100
Cont i ngency
Amount
$35,000
$31,500
$49,000
$42,000
$16,300
$25,000
$198,800
$397,600
$259,500
$125,000
$384,500
$782,100
$62,600
$23,500
$54,800
$923,000
$75,500
$2,300
$77,800
%
25
25
25
25
25
25
25
25
25
25
25
Cost with
Contingency
$175,000
$157,500
$245,000
$210,000
$81 ,300
$125,000
$993,800
$1,987,600
$1,297,500
$625,000
$1,922,500
$3,910,100
$312,800
$117,300
$273,800
$4,614,000
$377,200
$11,700
$388,900
Note: Replenishment
74
Table 7.15 Plan 8 - An Offshore Breakwater System in Reach 3 - Cost
Estimate
400 ft Offshore Breakwater:
Item Quantity Unit
Unit
Price
Cost without
Cont i ngency
Contingency
Amount %
Cost of each breakwater
Cost of 3 breakwaters
8 7. Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost
Total Annual Cost
$4,954,400
$14,863,200
$1,189,100
$445,900
$1,040,400
$17,538,600
$1,433,700
$87,700
$1,521,400
$1,238,600
$3,715,800
$297,300 25
$111,500 25
$260,100 25
$4,384,700
$358,400
$21,900
$380,300
Cost with
Contingency
A- 16 Stone
B-2 Stone
C-Stone
46,800
30,800
40,000
tons
tons
tons
$56.00
$42.00
$26.00
$2,620,800
$1,293,600
$1,040,000
$655,200
$323,400
$260,000
25
25
25
$3,276,000
$1,617,000
$1,300,000
$6,193,000
$18,579,000
$1,486,400
$557,400
$1,300,500
$21,923,300
$1,792,100
$109,600
$1,901,700
75
Table 7.16 Plan 9 - A Seawall in Reach 3 - Cost Estimate
Item
Mobilization & Demob
Sheet Pile Wall
Concrete Cap
1,500-pound Toe Rock
C-Stone
Filter Cloth
Subtotal Cost
Quant i ty
.
2
2
8
7
1
,700
,170
,090
750
,760
8 % Planning, Engineering,
3 % Engineering during
Unit
Unit Price
Job L.S.
In feet $475.00
cu yd $510.00
tons $31.00
cu yd $31.00
sq yd $3.70
and Design
Construction
7 % Construction Management
Total First Cost of
Annual Cost
Annual O&M Cost
Total Annual Cost
Construction
Cost without
Cont i ngency
$280,
$1,282,
$1,106,
$250,
$23,
$28,
$2,972,
$237,
$89,
$208,
$3,507,
$286,
$17,
$304,
000
500
700
800
300
700
000
800
200
000
000
700
500
200
Cont i ngency
Amount %
$70,
$320,
$276,
$62,
$5,
$7,
$743,
$59,
$22,
$52,
$876,
$71,
$4,
$76,
000
600
700
700
800
200
000
500
300
000
800
600
400
000
25
25
25
25
25
25
25
25
25
Cost with
Cont i ngency
$350
$1,603
$1,383
$313
$29
$35
$3,715
$297
$111
$260
$4,383
$358
$21
$380
,000
.100
,400
,500
,100
,900
,000
,300
,500
,000
,800
,300
,900
,200
Note: Design of seawall was obtained from the City of Carlsbad.
76
Table 7.17 Plan 10 - A Rubble-Mound Revetment in Reach 3 - Cost Estimate
Item Quantity Unit
Unit
Price
Cost without
Contingency
Contingency
Amount %
Subtotal Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&H Cost
Total Annual Cost
$2,920,700
$233,700
$87,600
$204,400
$3,446,400
$281,700
$17,200
$298,900
$730,200
$58,400 25
$21,900 25
$51,100 25
$861,600
$70,400
$4,300
$74,700
Cost with
Cont i ngency
A-6 Stone
C- Stone
58,410
9,740
tons
tons
$45.00
$30.00
$2,628,500
$292,200
$657,100
$73,100
25
25
$3,285,600
$365,300
$3,650,900
$292,100
$109,500
$255,500
$4,308,000
$352,100
$21,500
$373,600
77
Table 7.18
Estimate
Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3 - Cost
Unit
Item Quantity Unit Price
200-ft north intake jetty extension - Reach
A- 12 Stone 1,600 tons $50.00
A- 7 Stone 1,600 tons $45.00
B-1 Stone 3,200 tons $35.00
C-Stone 3,200 tons $30.00
Grouting 1 Job L.S.
Cost of Jetty Extension
350-ft groin - Reach 3:
A-12 Stone 2,800 tons $50.00
A-7 Stone 2,800 tons $45.00
B-1 Stone 5,600 tons $35.00
C-Stone 5,600 tons $30.00
Excavation 25,000 cu yd $6.50
Backfill 15,000 cu yd $6.50
Grouting 1 Job L.S.
Cost of 1 350-ft Groin
Cost of 2 350-ft Groins
Subtotal of Construction Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Cost of Jetty Extension & Groins
Cost of Initial Beachfill
Total First Cost of Construction
Annual Cost
Present Worth of Beachfill Replenishment (O&M)
Annual Cost of Beachfill Replenishment (O&M)
Annual O&M Cost of Structures
Total Annual Cost
Cost without
Contingency
1 and Reach 2:
$80,000
$72,000
$112,000
$96,000
$100,000
$460,000
$140,000
$126,000
$196,000
$168,000
$162,500
$97,500
$100,000
$990,000
$1,980,000
$2,440,000
$195,200
$73,200
$170,800
$2,879,200
$7,428,300
$10,307,500
$842,600
$4,525,900
$370,000
$14,400
$1,227,000
Contingency
Amount
$20,000
$18,000
$28,000
$24,000
$25,000
$115,000
$35,000
$31,500
$49,000
$42,000
$40,600
$24,400
$25,000
$247,500
$495,000
$610,000
$48,800
$18,300
$42,700
$719,800
$1,857,100
$2,576,900
$210,600
$1,131,500
$92,500
$3,600
$306,700
%
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Cost with
Cont i ngency
$100,000
$90,000
$140,000
$120,000
$125,000
$575,000
$175,000
$157,500
$245,000
$210,000
$203,100
$121,900
$125,000
$1,237,500
$2,475,000
$3,050,000
$244,000
$91,500
$213,500
$3,599,000
$9,285,400
$12,884,400
$1,053,200
$5,657,400
$462,500
$18,000
$1,533,700
Note: Replenishment = 6-year Cycle at 100,000 ydVyear
(See Table 7.7 for sensitivity analysis of replenishment cycle)
78
Table 7.19 Plan 12 - A Rubble-Mound Revetment in Reach 5 - Cost Estimate
Item
A-4 Stone
C-Stone
Quant i ty
13,620
2,550
Unit
tons
tons
i in; f.
Price
$43.00
$30.00
Contingency
$585,700
$76,500
Cont i ngency
Amount %
$146,400 25
$19,100 25
Contingency
$732,100
$95,600
Subtotal Cost
8 % Planning, Engineering, and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost
Total Annual Cost
$662,200
$53,000
$19,900
$46,400
$781,500
$63,900
$3,900
$67,800
$165,500
$13,300 25
$5,000 25
$11,600 25
$195,400
$16,000
$1,000
$17,000
$827,700
$66,300
$24,900
$58,000
$976,900
$79,900
$4,900
$84,800
79
Table 7.20 Plan 13 - A Groin System with Beachfill in Reach 1 - Cost
Estimate
Item Quantity
400 ft groin
A-12 Stone 3,200
A-7 Stone 3,200
B-1 Stone 6,400
C-Stone 6,400
Excavation 10,000
Grouting 1
Cost of each groin
Cost of 2 groins
Beachfill 533333
Mobilization & Demob. 1
Cost of Beachfill
Subtotal of Construction Cost
8 % Planning, Engineering,
Unit Cost without
Unit Price Contingency
tons $50.00
tons $45.00
tons $35.00
tons $30.00
cu yd $6.50
Job U.S.
cu yd $3.00
Job L.S.
(Beachfill + Groins)
and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost of Groins
Total Annual Cost
$160,000
$144,000
$224,000
$192,000
$65,000
$100,000
$885,000
$1,770,000
$1,600,000
$500,000
$2,100,000
$3,870,000
$309,600
$116,100
$270,900
$4,566,600
$373,300
$10,400
$383,700
Contingency
Amount
$40,000
$36,000
$56,000
$48,000
$16,300
$25,000
$221,300
$442,600
$400,000
$125,000
$525,000
$967,600
$77,400
$29,000
$67,700
$1,141,700
$93,300
$2,700
$96,000
%
25
25
25
25
25
25
25
25
25
25
25
Cost with
Contingency
$200,000
$180,000
$280,000
$240,000
$81,300
$125,000
$1,106,300
$2,212,600
$2,000,000
$625,000
$2,625,000
$4,837,600
$387,000
$145,100
$338,600
$5,708,300
$466,600
$13,100
$479,700
Note: Replenishment = 0
80
Table 7.21 Plan 14 - A T-Groin with Beachfill in Reach 3 - Cost Estimate
Item Quantity
350 ft groin:
A- 12 Stone 2,800
A-7 Stone 2,800
B-1 Stone 5,600
C-Stone 5,600
Excavation 10,000
Grouting 1
Cost of each groin
200 ft T-ends:
A- 12 Stone 3,200
B-1 Stone 3,200
C-Stone 3,200
Cost of T-ends
Cost of 1 T-groin
Beachfill 346,000
Mobilization & Demob. 1
Cost of Beachfill
Subtotal of Construction Cost
8 % Planning, Engineering,
Unit
Unit Price
tons $50.00
tons $45.00
tons $35.00
tons $30.00
cu yd $6.50
Job L.S.
tons $50.00
tons $35.00
tons $30.00
cu yd $3.00
Job L.S.
(Beachfill + Groin)
and Design
3 % Engineering during Construction
7 % Construction Management
Total First Cost of Construction
Annual Cost
Annual O&M Cost of Groins
Total Annual Cost
Cost without
Contingency
$140,000
$126,000
$196,000
$168,000
$65,000
$100,000
$795,000
$160,000
$112,000
$96,000
$368,000
$1,163,000
$1,038,000
$500,000
$1,538,000
$2,701,000
$216,100
$81,000
$189,100
$3,187,200
$260,500
$6,900
$267,400
Contingency
Amount %
$35,000 25
$31,500 25
$49,000 25
$42,000 25
$16,300 25
$25,000 25
$198,800
$40,000 25
$28,000 25
$24,000 25
$92,000
$290,800
$259,500 25
$125,000 25
$384,500
$675,300
$54,000 25
$20,300 25
$47,300 25
$796,900
$65,200
$1,700
$66,900
Cost with
Contingency
$175,000
$157,500
$245,000
$210,000
$81,300
$125,000
$993,800
$200,000
$140,000
$120,000
$460,000
$1,453,800
$1,297,500
$625,000
$1,922,500
$3,376,300
$270,100
$101,300
$236,400
$3,984,100
$325,700
$8,600
$334,300
Note: Replenishment = 0
81
Table 7.22 Carlsbad Summary Cost Estimate of Alternatives
First Cost
of
Construction First Cost
$7,448,900
Plan Description and Assumption of Alternatives
1 Beachfill in Reaches 1 and 2.
5,000 ft long and 200 ft wide beachfill.
Net longshore transport rate = 270,000 ydVyr.
Sand bypass = 100,000 ydVyr from Oceanside Harbor.
Replenishment = 170,000 ydVyr at 5-year cycle.
A Groin System with Beachfill in Reaches 1 and 2. $11,608,400
5,000 ft long and 200 ft wide beachfill
and 3 600-ft groins.
Net longshore transport rate becomes 135,000 ydVyr
due to reorientation of shoreline.
Sand bypass = 100,000 ydVyr from Oceanside Harbor.
Replenishment = 35,000 ydVyr at 10-year cycle.
An Offshore Breakwater System in Reaches 1 and 2. $43,846,400 3,584,100
3 800-ft offshore breakwaters with 800-ft gaps.
Annual Cost ($/year) of
O&M Total
New and Repaired Revetments in Reach 1.
New construction of revetments and repair of
existing revetments.
$1,347,900
$7,477,500Beachfill and North Intake Jetty Extension in
Reaches 1, 2, and 3.
7,400-ft beachfill and North Intake Jetty
extended to 600 ft long. Beachfill width varies
from 200 ft to 330 ft.
Net longshore transport rate becomes 135,000 ydVyr
due to reorientation of shoreline. Sand bypass:
100,000 yd3/yr from Oceanside Harbor and 60,000 yd3/yr
from Agua Hedionda Lagoon. Offshore loss = 25,000 ydVyr.
Replenishment = 0.
Beachfill in Reach 3. $5,985,500
2,700 ft long and 200 ft wide beachfill.
Net longshore transport rate = 270,000 ydVyr.
Sand bypass = 60,000 ydVyr from Agua Hedionda Lagoon.
Replenishment = 210,000 yd3/yr at 4-year cycle.
A Groin System with Beachfill in Reach 3.
2,700 ft long and 200 ft wide beachfill and 2
350-ft groins.
Net longshore transport rate becomes 130,000 ydVyr
due to reorientation of shoreline. Sand bypass
= 130,000 ydVyr from Agua Hedionda Lagoon.
Replenishment = 0.
$4,614,000
608,900 766,800 1,375,000
948,900
611,200
489,300
377,200
189,700 1,138,600
219,200 3,803,300
110,200 6,700 116,900
6,000 617,200
988,500 1,477,800
11,700 388,900
82
Table 7.22 (continued) Carlsbad - Summary Cost Estimate of Alternatives
First Cost Annual Cost ($/year) of
of
Plan Description and Assumption of Alternatives Construction First Cost O&M Total
8 An Offshore Breakwater System in Reach 3. $21,923,300 1,792,100 109,600 1,901,700
3 400-ft offshore breakwaters with 400-ft gaps.
9 A Seawall in Reach 3. $4,383,800 358,300 21,900 380,200
2,700-ft seawall.
10 A Rubble-Hound Revetment in Reach 3. $4,308,000 352,100 21,500 373,600
2,700-ft rubble-mound revetment.
11 Beachfill and Structures in Reaches 1, 2, and 3. $12,884,400 1,053,200 480,500 1,533,700
10,100 ft long and 200 wide beachfill, North
Intake Jetty extended to 400 ft long, and 2
350-ft groins.
Net longshore transport rate = 200,000 ydVyr.
Sand bypass = 100,000 ydVyr from Oceanside Harbor.
Replenishment = 100,000 ydVyr at 6-year cycle.
12 A Rubble-Mound Revetment in Reach 5. $976,900 79,900 4,900 84,800
1,000-ft rubble-mound revetment.
13 A Groin System with Beachfill in Reach 1. $5,708,300 466,600 13,100 479,700
4,000 ft long and 200 ft wide beachfill and
2 400-ft end groins.
Net longshore transport rate becomes 135,000 ydVyr
due to reorientation of shoreline. Sand bypass:
100,000 ydVyr from Oceanside Harbor and 60,000 ydVyr
from Agua Hedionda Lagoon. Offshore loss = 25,000 ydVyr.
Replenishment = 0.
14 A T-Groin with Beachfill in Reach 3. $3,984,100 325,700 8,600 334,300
2,700 ft long and 200 ft wide beachfill and one
350-ft T-groin.
Net longshore transport rate becomes 130,000 yd3/yr
due to reorientation of shoreline. Sand bypass
= 130,000 ydVyr from Agua Hedionda Lagoon.
Replenishment = 0.
83
A-8.0 REFERENCES
Ahrens, J.P. and B.L. McCartney. 1975. "Wave Period Effect on the Stability
of Riprap," Proceedings of Civil Engineering in the Oceans/Ill, American
Society of Civil Engineers, pp. 1019-1034.
Birkemeier, W.A. and S.J. Holme. 1992. "The User's Manual to ISRP 2.7, the
Interactive Survey Reduction Program," US Army Engineer Waterways Experiment
Station, Vicksburg, Mississippi. August 1992.
Cayan, D.R., et al. 1988. "January 16-18: An Unusual Severe Southern
California Coastal Storm," CSBPA Newsbreaker, July 1988.
City of Carlsbad. 1989. "City of Carlsbad Proposal for the Carlsbad Beach
Erosion Study and Coastal Shore Protection Project," April 1989.
Flick, R. 1991. State of the Coast Report, San Diego Region, Chapter 4,
Tides and Sea Levels, U.S. Army Corps of Engineers, Los Angeles District,
September 1991.
Flick, R.E. and D.R. Cayan. 1984. "Extreme Sea Levels on the Coast of
California," Proceedings of 19th Coastal Engineering Conference, American
Society of Civil Engineers, Pages 886 through 898.
Goda, Y. 1983. "A Unified Nonlinearity Parameter of Water Waves," Report of
the Port and Harbor Research Institute, Vol. 22, No. 3, pp. 3-30.
Hales, L.Z. 1978. "Coastal Processes Study of the Oceanside, California,
Littoral Cell," Miscellaneous Paper H-78-8, US Army Engineer Waterways
Experiment Station, Vicksburg, MS.
Harris, D. L. 1981. Tides and Tidal Datums in the United States, Special
Report No. 7, U.S. Army Coastal Engineering Research Center, February 1981.
Hickey, B.M. 1979. "The California Current System-Hypothesis and Facts,"
Progress in Oceanography, v. 8, n. 4, p. 191-279.
Holman, R.A. 1986. Extreme Value Statistics for Wave Runup on a Natural
Beach, Coastal Engineering 9. pp. 527-544.
Jensen, R.E., et al. 1992. "Southern California Hindcast Wave Information,"
WIS Report No. 20, US Army Engineer Waterways Experiment Station, Vicksburg,
Mississippi.
84
Lentz, S.J. 1984. "Subinertial Motions on the Southern California
Continental Shelf," Ph. D. Thesis^ Univ. of California, San Diego, Scripps
Inst. of Oceanography, La Jolla, CA., 145 pp.
Maloney, N. and K.M. Chan. 1974. A Summary of Knowledge of the Southern
California Coastal Zone and Offshore Areas, V. I, Report to the Bureau of Land
Management, Dept. of the Interior, Washington, D.C.
Marine Advisers. 1961. "A Statistical Survey of Ocean Wave Characteristics
in Southern California Waters, La Jolla, California," prepared for US Army
Engineer District, Los Angeles.
Marine Board, National Research Council. 1987. Responding to Changes in Sea
Level: Engineering Implications. National Academy Press, Washington, D.C.,
148 pp.
Miche, R. 1944. "Mouvements ondulatoires de la mer en profondeur constante
ou decroissante," Annales des Fonts et Chaussees, Vol. 114.
Moffatt and Nichol Engineers. 1988. "Sedimentation in Submarine Canyons in
San Diego County, California, 1984-1987," US Army Engineer District, Los
Angeles, Coast of California, Storm and Tidal Waves Study (CCSTWS) Report No.
88-2, 115 pp.
Moffatt and Nichol Engineers. 1990. "Sediment Budget Report, Oceanside
Littoral Cell," US Army Engineer District, Los Angeles, CCSTWS 90-2, Coast of
California, Storm and Tidal Waves Study, November, 1990.
NOAA, Sea Level Variations for the United States, 1855-1986, U.S. Department
of Commerce, National Oceanic and Atmospheric Administration, National Ocean
Service, February 1988.
Robinson and Associates, Inc. 1988. "Processes, Locations, and Rates of
Coastal Cliff Erosion from 1887 to 1947, Dana Point to the Mexican Border,"
U.S. Army Engineer District, Los Angeles, Coast of California Wave and Tidal
Waves Study (CCSTWS) Report No. 88-8.
Schwartzlose, R.A. and J.L. Reid. 1972. "Nearshore Circulation in the
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Fisheries Investigation, Cal COFI Report No. 16, p. 57-65. COE Ref # 410.
Shore Protection Manual. 1984. 4th Ed., Volumes I and II, US Army Engineer
Waterways Experiment Station, Government Printing Office, Washington, DC.
85
Simons, Li and Associates. 1988. "River Sediment Discharge Study, San Diego
Region," US Army Engineer District, Los Angeles, Coast of California, Storm
and Tidal Waves Study (CCSTWS) Report No. 88-3, 4 volumes.
Suh, K. and R.A. Dalrymple. 1987. "Offshore Breakwaters in Laboratory and
Field," Journal of Waterway, Port, Coastal and Ocean Engineering, American
Society of Civil Engineers, Vol. 113, No. 2, pp. 105-121.
Tekmarine, Inc. 1987. "San Diego Region Wind Transport and Wave Overwash
Report," US Army Engineer District, Los Angeles, Coast of California, Storm
and Tidal Waves Study (CCSTWS) Report No. 87-9, 36 pp. + Appendices.
Tekmarine, Inc. 1988. "Sand Thickness Survey Report, October-November 1987,
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California, Storm and Tidal Waves Study (CCSTWS) Report No. 88-5, August 1988,
21 pp.
Tekmarine, Inc. 1992. "Semi-Annual Beach Profile Surveys and Analysis for
October 1991," submitted to City of Carlsbad, California, March 1992.
US Army Engineer District, Los Angeles. 1984. "Geomorphology Framework
Report, dana Point to the Mexican Border," CCSTWS 84-4, Coast of California,
Storm and Tidal Waves Study, 75+ pp.
US Army Engineer District, Los Angeles. 1989. "Section 103 Small Project,
Reconnaissance Assessment Report, Carlsbad, San Diego County, California,"
February 1989.
US Army Engineer District, Los Angeles. 1990. "Section 103 Small Project,
Carlsbad Beach Erosion Control Reconnaissance Study, Carlsbad, San Diego
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California, Storm and Tidal Waves Study. Final - September 1991.
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County, CA., Storm Damage Reduction and Navigation Improvements, Design
Memorandum. August 1992.
Weggel, J.R. 1972. "Maximum Breaker Height," Journal of Waterways, Harbors
and Coastal Engineering Division, American Society of Civil Engineers, Vol.
98, No. WW4, pp. 529-548.
86
Woodward-Clyde Consultants. 1990. "Design Memorandum, Carlsbad Boulevard
Shore Protection, Carlsbad, California," prepared for City of Carlsbad,
California.
87
O
O
SAN FRANCISCO
SAN LUis\ CALIFORNIA \
OBISPOV «-
SANTA
BARBARA
VENTURA
LONG BEACH
CARLSBAD
SAN DIEGO
PROJECT
\LOCATION
SCALE
0 100 200 300 400
i ' 1 1 'MU.ES
Figure 2.1 Location Map of Carlsbad Study Area
88
wm
SCALE IN MILES
SOUNDINGS IN FATHOMS
Figure 2.2 Bathymetry of Carlsbad Study Area
89
San Diego Tide - Higher High Water
4567
Water Elevation (ft MLLW)
8
Figure 4.1 Statistical Distribution of Higher High Water at San Diego
90
10
0
o
u
-30
.Sou-M
Line
930
1000
1030
1070
Suruey
50
50
50
50
50
Time
1345
1230
1040
935
840
Date
11 APR 86
11 APR f6
11 APR E6
11 APR £6
11 APR £6
0 500 1000 1500 2800 2500
Distance. FT
3000 3500 4000
20
10
0
•2 -10
UP*4
"-20
-30
-40
0
Line
760
800
~B30~
900
4)
Suruey
50
50
"5F
50
Time
605
1530
"I5B5T
1345
Date
13 APR 86
11 APR 86
11 APR f&
11 APR (6
500 1000 1500 2000 2500 3000 3500 4000
FT
Figure 5.1 Comparison of Profiles by Location from Oceanside Harbor to
Carlsbad Submarine Canyon
91
SUBCELL km mi
to
oH,
XH-
wrtoi-!
H-n
en
H-
O3rr
DO
a
IQfDrt
Input or Output
Q/+Q,, Longshore
Q, River
Qfc,Q0 Bluff.Offshore
Qfl Nourish
av/at (103 yd3/yr)
ax/at (ft/yr)
Q/+Q,
Qr
av'/at (103 yd3/yr)
ax/at (ft/yr)
Deflection
Qr
av'/at (103 yd3/yr)
ax/at (ft/yr)
Hour.,Sub Canyon
av/at (io3 yd3/yr)ax/at (ft/yr)
Episodic Baacb
Denudationi
Natural
Conditions
ca.1900-1938
Uniform NW
Wave Climate
ca.1960-1978
Input Output Input output
Variable W
Wave Climate
ca.1983-1990
Input Output
1939 Tropical 1*82/83
Storm cluster Storms
/V
0 190
85 0
170 60
0 0
+5
« balance
190 270
270 0
520 640
0 0
+70
0.3 accretion
270 0
65 0
200 240
0 290
+3
« balance
0 190
60 0
120 60
120 0
+ 50
0.7 accretion
190 270
25 0
370 460
65 0
-80
0.6 erosion
0 80
270 270
40 0
160 180
100 0
+ 40
0.7 accretion
270 0
5 0
200 240
100 290
+ 45
0.3 accretion
1
0 50
60 0 .—
00 /
00 /
+ 10 /
« balance /
60 70
0 0
180 0
30 0
+200
1.4 accretion
0 20
70 70
0 0
80 0
0 0
+ 60 t
1.0 accretion /
70 0
0 0
100 0
0 70
+ 100
0.6 accretion y
1 /
NORTH 14 8.5
CENTRAL 27 16.5
Oceanside
Harbor
11 7
Carlsbad
Submarine
.Canyon
SOUTH 32 20
Scripps/La Jolla
Submarine
Canyon
Pt La Jolla 84 52
Summary of the Budgets of Sediment for Oceanside Littoral Cell
in IO3 yd3/yr.
Santa
Margarita'
River
San Luis
Rey
River
Oceanside
270 / *\ X NV^TA^
VN 2°°/ N %
+ \100
70
\
\
VX
\3acific Ocean ^y/
30 \
^
LEGEND
Chanae in
-60| Littoral Sediment
Volume (OOO's y3/yr)
XX Buena
\J-60l \/7 Vista
y~ ?K Laaoon
X / /X
\* \
\r-A\I-30K
X^\v^v
Vl> \\ x\ ^s\N\\\\\\\\\\\\\\
\
Agua
Hedionda
Lagoon
\\\v \\ X\ X\ X\ X\ X\ x\ \\ ^
\\
\
V"''
270
200
Sediment Flux Rate
(OOO's y3/yr)
Harbor Dredging
Carlsbad
Batiquitos
Lagoon
270
Without Project Sediment Budget
(OOO's y3/yr)
Sources
Northern Boundary: 100
Harbor Dredging: 200
S.LR. River 10
Total:310
Sinks
-100 Northern Transport into Harbor
-270 Net Southern Transport
-30 Offshore Losses
^00 Total
NET VOLUME CHANGE = -90
Figure 5.3 Future Without Project Sediment Budget
93
Figure 6. la Five Reaches of Carlsbad Coastal Area
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
94
Figure 6.Ib Reach 1 and Reach 2 of Carlsbad Coastal Area
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
95
Carlsbad
Figure 6.1c Reach 3 of Carlsbad Coastal Area
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
96
Carl
Figure 6. Id Reach 4 of Carlsbad Coastal Area
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
97
Figure 6.le Reach 5 of Carlsbad Coastal Area
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
98
Figure 6.2a Typical Structure of Carlsbad - Reach 1, Cross-Section 1
H-
co
r-l
Q)i — i
UJ
50 --
0 --
Carlsbad
Reach 1 - Section 1
Hard Pan +33' MLLW
Earth Slope 1:7
Profiles:
Maximum
Mean
MinimumRevetment 1:2.
0.5 to 2. tons
Sand Beach 1:5
0
Horizontal Distance (ft)
100
Figure 6.2b Schematic Profile of Carlsbad - Reach 1, Cross-Section 1
100
Figure 6.2c Typical Structure of Carlsbad - Reach 1, Cross-Section 2
LU
Carlsbad
Reach 1 - Section 2 Profiles:
•Hard Pan +33'MLLW
Glass Door
Maximum
Mean
Minimum
First Floor +16JB' MLLW
Sea Wall
Sand Beach 1:5
100
Horizontal Distance (ft)
Figure 6.2d Schematic Profile of Carlsbad - Reach 1, Cross-Section 2
102
V
Figure 6.2e Typical Structure of Carlsbad - Reach 1, Cross-Section 3
Carlsbad
Reach 1 - Section 3
Hard Pan +3.3' MLLW
50 +
c
0
rH
+>
10
UJ
04-
Profiles:
Maximum
Mean
Minimum
First Floor -17.8'MLLW
Riprap 1:3 (1-ton Stones)
Sand Beach 1:5
-50 100
Horizontal Distance (ft)
Figure 6.2f Schematic Profile :f Carlsbad - Reach 1, Cross-Section 3
104
S"
Figure 6.2g Typical Structure of Carlsbad - Reach 1, Cross-Section 4
co
r-H
•P10>
CDt—i
UJ
50 --
Carlsbad
Reach 1 - Section 4
First Floor +43'MLLW
Hard Pan +33' MLLW
Earth Slope 1:1.5
Sand Beach 1:5
Profiles:
— Maximum
— Mean
— Minimum
700
Horizontal Distance (ft)
Figure 6.2h Schematic Profile of Carlsbad - Reach 1, Cross-Section 4
106
50
c
0I-t-p
10>
0)1—I
LU
0 +
Carlsbad
Reach 2
+I2.8'MLLW
Earth Slope 1:2.
Sea Wall
Sand Beach 1:5
Profiles:
— Maximum
-- Mean
— Minimum
l_l_u-
50 100
Horizontal Distance (ft)
Figure 6.3 Schematic Profile of Carlsbad - Reach 2
107
H
O
CO
CDntr(D
0)rtH-n
ti
ol-h
n01
COcro>
Carlsbad
Reach 3
c0
rH+>10>
0)
r—I
LU
Carlsbad Blvd. +I6JB'MWN
Hard Pan -63'MLLVt
Profiles:
Maximum
Mean
Minimum
Sand Beach 1:5
100 /£
Horizontal Distance (ft)
250 300
Figure 6.5a Typical Structure of Carlsbad - Reach 4, Cross-Section 1
L
0
rH
+>o>
CDi—i
UJ
Carlsbad
Reach 4 - Section 1
50 --
o --
Profiles:
First Floor +38'MLLW
Earth Slope 1:2.
Hard Pan +2.8'MLLW
Riprap 1:2. (2-ton Stones)
Sand Beach 1:4
Maximum
Mean
Minimum
saagaaaaa—aaag...
i ' ^o ' 10100
Horizontal Distance (ft)
Figure 6.5b Schematic Profile of Carlsbad - Reach 4, Cross-Section 1
110
Figure 6.5c Typical Structure of Carlsbad - Reach 4, Cross-Section 2
-p 50 --
co
>
<Di—i
Id
Carlsbad
Reach 4 - Section 2
First Floor +41'MLLW
Earth Slope 1:2.
Hard Pan +2.B' MLLW
Gunfte Slope 1:1
Beach I.-4
-^
Profiles:
— Maximum
--- Mean
— Minimum
Kfszaasz
&100
Horizontal Distance (ft)
Figure 6.5d Schematic Profile of Carlsbad - Reach 4, Cross-Section 2
112
50 --
co
rH
-P
ID>
0)i—iu
0 --
Carlsbad
Reach 5
State P0r/r Campground +63' MLLW
Earth Slope 1:1
Hard Pan +0.8'MLLW
Cobble Beach 1:4
Profiles:
— Maximum
--- Mean
— Minimum
100
Horizontal Distance (ft)
Figure 6.6 Schematic Profile of Carlsbad - Reach 5
113
H-
?n
CTl
•-J
t)
l-l0
Hi
H-
nw
w
H-tn
OHI
cn
H-
3
CD
0)
CD
OV0)
IQCDCO
to
?3
13
S. of Batiquitos
PROFILE CHANGE SUMMARY TABLE
Datum: MLLW
Loc.
Code
CF
CF
CF
CF
CF
CF
CF
CF
CF
CF
Profile Survey
No. No. Date
Start Max.
Dist. Dist.n ft Cum.
Years
Shoreline
Change
ft
Above
Datum
Vol. Chg.
yd3/ft
Below
Datum
Vol. Chg.
yd3/ft
Net
Profile
Vol. Chg.
yd3/ft
Gross
Profile
Vol. Chg.
yd3/ft
Cum.
Shoreline
Change
ft
Cum.
Net Vol.
Change
yd3/ft
Cum.
Above
Datum
ydSffi
720
720
720
720
720
720
720
720
720
720
1 01/04/34
2 04/01/57
3 10/01/70
10 10/18/83
20 05/21/84
30 11/27/84
50 04/13/86
60 10/04/86
70 04/13/87
90 01/26/88
0
0
0
0
0
0
0
0
0
0
1300
1300
1300
1300
1300
1300
1300
1300
1300
1300
0
23.2
36.7
49.8
50.4
50.9
52.3
52.7
53.3
54.1
0
-8.33
107.14
-63.83
-184.85
116.31
-142.29
194.58
-184.89
1.41
0
-0.4
40.85
-13.68
-22.33
7.62
-8.87
20.87
-20.25
3.05
0
15.59
41.19
-77.22
24.47
-20.35
51.47
-65.25
-22.96
-14.43
0
15.19
82.04
-90.9
2.15
-12.73
42.6
-44.38
-43.2
-11.38
0
27.61
83.18
124.12
99.48
73.34
116.18
107.38
100.47
80.86
0
-8.33
98.81
34.98
-149.87
-33.56
-175.85
18.73
-166.15
-164.74
0
15.19
97.22
6.32
8.47
-4.26
38.34
-6.03
-49.23
-60.62
o
-0.4
40.45
26.77
4.44
12.06
3.19
24.07
3.82
6.87
20 30
Years since Jan 1934
40 50 60
-•- cumulative shorelline change -«•- cumulative volume change )
nre
o\
CD
3
H-
I-"
CD
8
Carlsbad State Beach
PROFILE CHANGE SUMMARY TABLE
Datum: MLLW
Loc.
Code
Profile Survey
No. No. Date
Start
Dist.
ft
Max.
Dist.
ft
Cum.
Days
Shoreline
Change
ft
Above
5 Datum
Vol. Chg.
yd3/ft
Below
Datum
Vol. Chg.
yd3/ft
Net
Profile
Vol. Chg.
yd3/ft
Gross
Profile
Vol. Chg.
yd3/ft
Cum.
Shoreline
Change
ft
Cum. Cum.
3 Net Vol. Above
Change Datum
yd3/ft yd3/ft
CF
CF
CF
CF
760
760
760
760
50 860413
60 861004
70 870413
80 870921
0 2000
0 2000
0 2000
0 2000
0
174
365
526
0
94.24
-26.38
53.98
0
3.76
-5.69
7.55
0
-22.62
37.5
-16.48
0
-18.86
31.82
-8.93
0
81.86
72.12
77.71
0
94.24
67.86
121.84
0
-18.86
12.95
4.02
0
3.76
-1.93
5.62
&0)
(0
H-
Cfl
OHi
to
l-i
CD
M
P-
0>a
I
O
0)3IQIDCO
H
H
100 200 300
Days from 04/13/86
400 500 600
cumulative shorelline change cumulative volume change
13
REACH 4
PROFILE CHANGE SUMMARY TABLE
IS Datum: MLLW•s
n> Start Max.
cr, Loc. Profile Survey Dist. Dist.
(o Code No. No. Date ft ft
Above Below Net Gross
Shoreline Datum Datum Profile Profile
Cum. Change Vol. Chg. Vol. Chg. Vol. Chg. Vol. Chg.
Days ft yd3/ft yd3/ft yd3/tt yd3/tt
Cum. Cum. Cum.
Shoreline Net Vol. Above
Change Change Datum
ft yd3/ft yd3/ft
o
Ml
H-
nOBODoo
CF
CF
CF
CF
CF
CF
800 3 701001 0 2000 00 0 0 0 0000
800 5 720201 0 2000 488 134.03 15.15 45.13 60.28 75.38 134.03 60.28 15.15
800 50 860411 0 2000 5667 -114.43 -9.05 1.11 -7.94 53.99 19.61 52.33 6.1
800 60 861004 0 2000 5843 117.66 1.08 -48 -46.92 54.34 137.27 5.41 7.18
800 70 870413 0 2000 6034 -72.11 6.85 41.92 48.76 57.06 65.16 54.18 14.02
800 80 870921 0 2000 6195 94.5 0.21 -6.88 -6.67 43.98 159.66 47.5 14.23
50>
CO
H-
W
O
Mi
8"
i-1-
0>3a
c
(D
9»
IQn>
CO
o
1000 2000 3000 4000
Days from 10/26/83
5000 6000 7000
-•»-- cumulative shorelline change -°»- cumulative volume change |
13
H-
1-1n>
tiHo
otooo
CO
o
&CU
W
H-
W
O
Hi
CO
O
1-1
H-3CD
0)aa
o
h-1
c
0>
ntr
Q)3
iQ(Dca
Carlsbad - Reach 2
PROFILE CHANGE SUMMARY TABLE
Datum: MLLW
Loc.
Code
CF
CF
CF
CF
CF
Profile Survey
No. No. Date
Start
Dist.
ft
Max.
Dist.
ft
Cum.
Days
Shoreline
Change
ft
Above
Datum
Vol. Chg.
yd3/ft
Below
Datum
Vol. Chg.
yd3/ft
Net
Profile
Vol. Chg.
yd3/ft
Gross
Profile
Vol. Chg.
yd3/ft
Cum.
Shoreline
Change
ft
Cum.
Net Vol.
Change
yd3/ft
Cum.
Above
Datum
yd3/ft
830
830
830
830
830
50 860411
60 861004
70 870413
80 870922
90 880127
0
0
0
0
0
2000
2000
2000
2000
2000
0
176
367
529
656
0
23.63
-13.61
-2.43
-31.83
0
-1.48
-7.36
8.26
-4.3
0
-60.79
11.74
33.35
60.47
0
-62.27
4.38
41.61
56.17
0
72.99
88.53
76.37
98.22
0
23.63
10.02
7.59
-24.24
0
-62.27
-57.89
-16.27
39.89
0
-1.48
-8.84
-0.58
-4.88
-80 -4-
100 200 300 400
Days from 10/26/83
500 600 700
-•*- cumulative shorelline change -«•»- cumulative volume change |
to
H
H
CD
nCD
cn
t)
oMi
oo
caH-
CO
OHI
cn
o
<D
M-30)
0)aa
0>
oyDJa
(Qn>w
Mv
13
South Oceanside
PROFILE CHANGE SUMMARY TABLE
Datum: MLLW
Carlsbad - Reach 1
Loc. Profile Survey
Code No. No.Date
CF
CF
CF
CF
CF
CF
CF
900
900
900
900
900
900
900
150
-100
Start
Dist.
ft
Max.
Dist.
ft
Cum.
Bays'
Shore!
Chang
ft
Qve
turn
I. Chg.
>/ft
Below
Datum
Vol. Chg.
yd3/ft
Net
Profile
Vol. Chg.
yd3/ft
Gross
Profile
Vol. Chg.
yd3/ft
Start Max.Shoreline Datum Datum Profile Profile
Cum. Cum. Cum.
Shoreline Net Vol. Above
Change Change Datum
ft yd3/ft yd3/ft
Shoreline Net Vol. Above
2 09/07/61
5 0201/72
50 04/11/86
60 10/04/86
70 04/13/87
80 09/22/87
90 01/26/88
0
0
0
0
0
0
0
2000
2000
2000
2000
2000
2000
2000
0.0
10.4
24.6
25.1
25.6
26.0
0
-30
30.83
119.85
-111.09
94.92
26.4 -204.05
0
-22.15
11.31
19.86
-15.34
18.35
-28.73
0
-24.7
18.91
-35.79
61.02
-18.61
2.11
0
-46.85
30.22
-15.94
45.68
-0.26
-26.62
0
65.38
147.01
137.44
118.49
94.99
191.39
0
-30
0.83
120.69
9.6
104.52
-99.53
0
-46.85
-16.64
-32.57
13.11
12.85
-13.77
30
Years from Sep 1961
cumulative shorelline change -*»- cumulative volume change I
o
-22.15
-10.84
9.02
-6.32
12.03
-16.7
Faunaatton
Structure to bluff edge
Varies OPPTOX.B to 32 ft.
Horlzontol Projection of IS Slope
Existing
coastal Huff
Grade beam ft slab
Foundation
Sand ft cobble
Beach
Hard pan
Figure 6.12 Schematic of Structure on Bluff
119
1rt>
o>Carlsbad
too
toI—"cMi
M
O01p-
§ ^
< -^CD M—
Mc:w c
td O
n (/)n> ^~to Ow ^
s LJD)
* ^
40
30
20
10
0
7 8
Excess Runup (ft)
40 1983 Storm Data
D
30
1988 Storm Data
A
Localized Retreat
Average Retreat
20
Farthest House
Closest House
10
0
10
4BB 8BB
Figure 7.la Plan 1 - Beachfill in Reaches 1 and 2 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
121
Hto
to
1(D
v]
oHi
(D
D)nyHI
013
COQlntrHI
n>Qln3-
to
n
01
onotow
(1)nrrH-O
Elevation (ft-MLLW)
50
45
40
35 -
30
25
20
15 —
10
5
0
-5
-10 —
Line CB-850, Pine Avenue
-15
October 1991
October 1990
0 100 200 300 400 500 600 700 800
Range (feet seaward of range line monument)
900 1000
123
fD
•~J
totr
"o D>H- 3n0) to
to
9"w ow ni O
CO H-ro 3nrt wH- ^
O CO3 rtfl>O 3
Ml
0 5-I-! rtO CT
H-3 Wn>
(DncrHI
H-
CDQin
n>w
SYM. ABOUT
€
6'
B-l STONE
A-/2 S7"0/VE
•C-STONE EXISTING BOTTOM
to
I
Figure 7.3a Plan 3 - An Offshore Breakwater System in Reaches 1 and 2 -
Schematic. (Datum of bathymetry is MSL which is +2.75 feet MLLW)
125
l-l
(D
^J
Ul
HtO
<T\
•d
n
DJ[ '
n
oCOwi
CO
CDnrt
H-o3
o
Hi
oHi
Hi
0)3
U)
1
&
0HIHI
CO£J*o1-1
w
CD
Qi
^0>w rt
3" CD
O H
CD W
W COf"^ rtCD CD
tt 3
« H-0) 3rt
CD 501-1 CD
0)n
CDCO
OCE/W SIDE
E LEV.VARIES A-16 STONE
B-2 STONE B-2. STONE
3Q-
to
Figure 7.4a Plan 4 - New and Repaired Revetments in Reach 1 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
127
Quorrystone Armor
2
Existing Beach Grovel Blanket 0.3m Thick
Over Regraded Bank
Elev. -0.3m
Figure 7.4b Plan 4 - New and Repaired Revetments in Reach 1 - Typical
Cross-Section of Revetment
128
Figure 7.5 Plan 5 - Beachfill and North Intake Jetty Extension in Reaches
1, 2, and 3 - Schematic. (Datum of bathymetry is MSL which is +2.75 feet MLLW)
129
Carlsbad
Figure 7.6a Plan 6 - Beachfill in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
130
UJ
?ro
-o
tr
ro tiCD MQJ CD
O 3
Mi <T\
H-H-1 IM
tD
ft)
Q)ntrHI
H-
n31
n
0)
nI-!ontoieno>nnH-o
Elevation (ft-MLLW)
30
25 —
20 —
15
10
Line. CB-820, Agua Hedionda - South
0 —
-5 —
-10 —
-15
October 1991
October 1990
0 100 200 300 400 500 600 700 800
Range (feet seaward of range line monument)
900 1000
Carlsbad
Figure 7.7a Plan 7 - A Groin System with Beachfill in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
132
OJ
U>
c
(D
-J
cr
n 13
o 01W DM
co
(D inrt |>
H-o o
3 ^o
O H-
Hi 13
h)o
co
^tnrr(D
rtcr
CBCDttncrHI
H-
H-a
n
SYM. ABOUT
c
B-l STONE
ELEV. VARIES
A-12. STONE
•C-STONE •EXISTING BOTTOM
H-n
Carlsbad
Figure 7.8a Plan 8 - An Offshore Breakwater System in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
134
TJH-
CDtr
in
n 13
H MO 0)w 3wI 00coro iasOD OHI
O Hi
Hi Cfi
O OHi hHI ro
cr oaO i-iM n>ro Q)
CD s:hi (1)(D rtB) ro
£D) cort •<(D W
M l~f(D3
X)(DQ)n3*
OCEAN SIDE
E LEV.VARIES A-16 STONE
B-2 STONE B-2. STONE
n
0)
Carlsbad
Figure 7.9a Plan 9 - A Seawall in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
136
HOJ
CD
^1
0)
CD
0)
p-
3
CD0)n3-
n
(D
n^ow
COIenCDnrt
cnCD
0)
0)
G/NCH THICK QUAKRY XUM MAT&
UNDERLAIN BY FILTER FABRIC
tei&'filie*'-'*?'-^-'•>• '* '• -'• -~'kvis***' •.*.("' r*».'V i'. L. ' ' . •- .^*.«.:<N.y^.lJi:*«V.»'.'. .:•
Figure 7.10a Plan 10 - A Rubble-Mound Revetment in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
138
Top of Carlsbad Blvd.
Elev. +16.8' MLLW
Elev. +17.8' .MLLW
6-ton Quorrystone Armor'
1.5
Existing Beach
Z
1.5' thick core layer
of C-Stone
Elev. -6.3' MLLW
Figure V.lOb Plan 10 - A Rubble-Mound Revetment in Reach 3 - Typical
Cross-Section of Revetment
139
f r.nrlsbad it-
7.11 Plan 11 - Beachfill and Structures in Reaches 1, 2, and 3
- Schematic. (Datum of bathymetry is MSL which is +2.75 feet MLLW)
140
Figure 7.12 Plan 12 - A Rubble-Mound Revetment in Reach 5 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
141
Figure 7.13 Plan 13 - A Groin System with Beachfill in Reach 1 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
142
Figure 7.14 Plan 14 - A T-Groin with Beachfill in Reach 3 - Schematic
(Datum of bathymetry is MSL which is +2.75 feet MLLW)
143
ATTACHMENT
TO
COASTAL ENGINEERING APPENDIX
BEST ORIGINAL
B-155
oo-I
IUz
UJ
CD
Z
00i
UJ
OCID
O OS-tO70 '
O
UJ
B-156
co
-i-H
-Mra>cuI—I
UJ
0 200 400 600 BOO 1000 1200
Distance, FT
1400 1600 1800 2000
co
ro>cu
I— I
LU
Date
OCT 83
APR 8f>
-10
-20
-30
-40
0 200 400 600 800 1000 1200
Distance. FT
1400 1600 1800 2000
co
CD
r— IUJ
Date
OCT 7(
FEB 1\\
-10
-20
-30
-40
0 200 400 600 BOO 1000 1200
Distance, FT
1400 1600 1800 2000
Carlsbad - Reach 2
co
(U>
CDt—(
LU
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Distance. FT
co
-tH
-Mto
>
03
r—I
LU
Date
APR Bffi
OCT Bti
-10
-20
-30
-40
0 200 400 600 BOO 1000 1200
Distance. FT
1400 1600 1BOO 2000
co
•M
-Mra>
OJ
I—I
LU
200 400 600 BOO 1000 1200
Distance, FT
1400 1600 1800 2000
ca
(D>
CD
r— I
LU
Date
13 APR Bffi
13 APR Bfi
11 APR Bfi
1DUD
1345
11 AHH at)
11 APR Bfi
-20
-40
-60
0 500 1000 1500 2000
Distance, FT
2500 3000 3500
co
-rH
-Pro>o>i—i
LU
Date
13 APR B
13 APR B
13 APR B
Time
1735
1520
1300
-e 760
-x BOO
Id APR b
13 APR B
-20
-40
-60
0 500 1000 1500 2000 2500
Distance. FT
3000 3500 4000
PII
OJto
600
1880
PHOTOS. w,...d bound
MOS. MHW nhor«lin«
L
IE1TY (OUST. MHCDIC'NOA
1900 1920 1940
TIME
1960 1980 2000
PII
CO
CO
600
BFACHHLL ON AGUA
Hr.DIOtlDA BF.ACHr.5CONST. AT
AC.UA I It IH ONI)A
D AERIAL PHOTOS, welled bound
4- N05, MHW shorelined 200
1880 1900 1980 2000
w
600
JE1TV C.OMf.T. Al
A(;UA
1880
.I
1900
0 AERIAL PHOTOS, w,1t«d bound
4- HOS, MHW shoreline
1920 1940
TIME
1960 1980 2000
to
600
o> 500
Q)
O 400
2 300
LU
u,
C£
O
200
100
0
CB 830
.IF.TTY COMST. AT
ACIM HEOIONOA
BF.ACHntL ON AGUA
HEDIONDA BEACHF.S
\J
D AERIAL PHOTOS, welted bound
+ NOS, MHW shoreline
1880 1900 1920 1940
TIME
1960 1980 2000
PI
600
D AERIAL PHOTOS, wetted bound
-\- NOS, MHW shoreline
RrvcT * GROIN Q C 900
OC.BCACH 19^0=5 W ~> ^
KACHnu. (*i oc. SIDEnr.v:H \o5f-- '982oc sior HARBOR
BEACHFILL AT
S OMOrRE B' H
1880 1900 1920 1940
TIME
1960 1980 2000
LJ
2000
SHORELINE POSITION, feet
1500
1000
500
CB 760
MHHW
MSL
MLLW
-B- -5
-X- -15
30
83 83.5 84 84.5 85 85.5 86 86.5 87 87.5 88 88.5 89 89.5 90
YEAR
o
2000
SHORELINE POSITION, feet
1500
1000
500
-0-MHHW
CB 800
-15 -30
-x>< xx
70 72 74 76 78 80
YEAR
82 84 86 88 90
2000
SHORELINE POSITION, feet
1500
U)
U1
1000
500
CB 830
MHHW
MSL
MLLW
-X- -15
-30
84 84.5 85 85.5 86 86.5 87 87.5 88 88.5 89 89.5 90
YEAR
o
u
SHORELINE POSITION, feet
2500
2000
1500
1000
500
69 71 73 75 77 79 81 83 85 87 89
61 63 65 67
PAClriC OCEAN:
SAN DIEGO FREEWAY
B'JENA VISTA
LAGOON
November- : \
\June 1=536 September ".
Nove-ber 1=177OF RECC^EO
DATA FOR J;JNE 1=538
' •?, *-!E END)END CF P
T^ FG^ A=RiL '.^
(IF IT IS THE END)
-April 1
-September- 1S60
-June 1=174
—November 1*^7
•"January i°<88
GENERAL NOTES: -ote-fronx structures oreLocations OT roods, rivers. «nd -o^ e ncle Mops.
opprcximote os digitzec • rorr obb-
-r. : a~>ber^. coordinates.Grid pcmts a-e -e-e-e-cec ,c ..a oe
Cohfornio Coordinate System, Zone D.
A DB
CCSTWS be-ichmor'.s.
REVISIONS
F^" ^-fet"" '^^y^^gg^j^.
OCSICNED •»>
C. OARRAH
^ 3*AH*) •"!i
J. CARLSON
C><C«ED m
R. NATHAN
U.S. ARM1 ENGINEER DISTRICT
LOS ANGELES
CORPS Of ENGINEERS
COASTSTORK BNDSON
OCEAN
HISTORIC
OF CALIfORXIP
TIDAL WAVES STUOY
CIEGO REGION
SHORELINE POSITIONS
5IDE LITTORAL CELL
SHORELINES iS38-n88
MAP OS-iiA
5j3«TIEO B<: :«TEfc33^;;v = D.
5ST *=«5
-
CIS'BICT F!LC -JO.
33
at
64
S-fr'5
' A-PAYS
{IS. tan ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERS
o
-1987-89
-1333-34
-1960
-1972
-March 1982
Field Survey
Field Survey
Field Survey
Field Survey
Aerial
GENERAL NOTES:
Locations of roads, rivers, and waterfront structures are
approximate as digitzed from USGS Quadrangle Maps.
Grid points are referenced to Lambert coordinates.
California Coordinate System, Zone 6.-.
& DB 1850 (typical): Location and designation of
CCSTWS benchmarks. ZGRAPHIC SCALES IN FEET
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN DIEGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSICE LITTORAL CELL
NCS SHORELINES 1887-1982
MAP OS-11B
SUBMITTED BTl
DISTRICT FI_E NO.
34
OF
E4
8CETS
CALTjTTV D A V Q
VAI UE F.MRTNEERING PAYS
SUENA VISTA
LAGOON
February 1S83
July 1^82 May
September 1<184
September 1S84February 1S83
uiy 1SS2
X
OS. ARMY ENGINEER DISTRIC
LOS ANGELES
CORPS OF ENGINEERS
OF CALIFORNIA
STORM AMD TIDAL WAVES STUDYQIEGO REGION
Aerial
Aerial
Aertal
Aerial
Asrial
aonsoro.( -aterfront structures are
approximate as digitzed from USGS Quadrangle Maps.
July i°,S2
Febru
March HISTORIC SHORELINE POSITIONS
CCEANSIO£ LI~TORAL CELL
SEASONAL SriORELlNES iq82-iS85
OS-11C
Grid points ore referenced to Lambert coordinates.
California Cocro'inaxe System. Zone 6.
A DB 1850 (typical): Location and designation of
CCSTWS benchmarks. ^.GRAPHIC SCALES IK FEET
Morch 1986
September 1986
November 1987
'J.S. (WHY ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERS
o
-Morch 1986
-September 1986
-April 1987
-November 1987
Aerial
Aerial
Aeriol
Aerial
GENERAL NOTES:
Locations of roads, rivers, and waterfront structures are
approximate as digitzed from USGS Quadrangle Maps.
Grid points are referenced to Lambert coordinates,
California Coordinate System, Zone 6.
A 08 1850 (typical): Location and designation of
CCSTWS benchmarks.^GRAPHIC SCALES IN FEET
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN SIEGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
SEASONAL SHORELINES 1986-1987
MAP GS-UD
SUBMITTED BTl : 5"£c. NO. OKCvn- .i
! DISTRICT FILE NO.
SHEET
36
OF
£4
SHEETS
Q
March 1964
April 1954
April 1968
Manuara 1988
November 1977
Plate E
-April 1954 Aerial
-September 1960 Aerial
-March 1964 Aerial
-April 1968 Aerial
-June 1974 Aerial-November 1977 Aerial
-JonuorLj 1988 Aerial
Aerial
GENERAL NOTES:
Locations of roods, rivers, ond waterfront structures ore
opproximate os digitzed from USGS Quodrongle Mops.
Grid points ore referenced to Lombert coordinotes,
California Coordinate System, Zone 6.
A DB 1850 (typical): Locotion and designation of
CCSTWS benchrnorks. XGRAPWC SCALES IN FEET
J.CMLSOH
UNkTIWN
U.S. HOMY ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERS
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN DIEGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
HISTORIC SHORELINES 1954-1S88
MAP OS-12A
aHMTTEOm SPEC. MO. mom-
DISTRICT FILE NO.
-55f
37
OF
64
.SHEETS
c
PACIFIC OCEAN
SAN DIEGO FREEWAY
fter rose
CB0830
U£.MMV ENGINEER DISTRICT
LOS ANGELESORTS OF ENGINEERSGENERAL NOTES:
Locations of roads, rivers, ond waterfront, structures ore
approximate as digitzed from USGS Quadrangle Mops.
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN DIEGO REGION
1887-83
1933-34
I9601972
Morch
Field Survey
Field Survey
Field Sur»eu
Field Survey
Aerial
HISTORIC SHORELINE POSITIONS
OCEANSIOE LITTORAL CELL
NOS SHORELINES 1934-1982
MAP OS-12B
Grid points ore referenced to Lombert coordinates,
California Coordinate System, Zone 6.
DB 1850 (tupioal): Locotion and designation of
CCSTWS benchmarks. XCRAPHK SCALES w FEET
o
o
February 1983
March 1984
September 1984
July 1982
July 1982 Aerial
February 1983 . Aerial
March 1984 Aerial
September 1984 Aerial
May 1985 Aerial
GENERAL NOTES:
Locations of roods, rivers, and woterf ront structures ore
approximate as digitzed from USGS Quadrangle Maps.
Grid points are referenced to Lombert coordinates,
California Coordinate System, Zone 6.
A OB 1850 (typical): Location ond designation of
CCSTWS benchmarks. ZGRAPHIC SCALES IN FEET
REVISIONS
IIS. ARMY ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERS
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN DIEGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
SEASONAL SHORELINES 1982-1S85
MAP OS-12C
SUBMITTED BYi sPEc.no.mcm- -
DISTRICT FIUZ NO.
SHEET
31
OF
64
o
6
April 1987
November 1987
END OF RECORDED DATA
March 1986
September 1986
April 1987
November 1987
Aerial
Aerial
Aerial
Aerial
GENERAL NOTES:
Locations of roads, rivers, and waterfront structures are
approximate as digitzed from USGS Quadrangle Mops.
Grid points are referenced to Lambert coordinates,
California Coordinate System, Zone 6.
A DB 1850 (typical): Location and designation of
CCSTWS benchmarks. XORAPWC SCALES IN FEET
REVISIONS
US. ARMY ENGINEER DISTRICT
LOS ANGELES
CORK OF ENGINEERS
COAST OF CALIFORNIA
STORM AND TOM. WAVES STUDY
SAM 01EGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
SEASONAL SHORELINES 1986-1987
MAP OS-12D
SUBMITTED BYl DATEAPPROVED)SPEC.MXOACMn- -
MSTR1CT HUE MX OF
£4
Oii
O
O
END OF RECORDED DATA
U.S.HRMY ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERS%
May 1954 Aerial
September 1960 Aerial
Morch 1964 Aerial
April 1968 Aenol
June 1974 Aerial
November 1977 Aerial
January 1988 Aerial
GENERAL NOTES:
Locations of roads, rivers, and waterfront structures are
approximate as digitzed from USGS Quadrangle Maps.
Grid points ore referenced to Lambert coordinates,
California Coordinate Sustem, Zone 6.
A DB 1850 (typical): Location and designation of
CCSTWS benchmarks. XGRAPHIC SCALES IN FEET
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN DIEGO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
HISTORIC SHORELINES 1954-1988
MAP OS-13A
SUBMITTED BY.'SPEC. to. mom- —B-._
I OtSTRICT FILE MO-
1 »€ET
' 4:
OF
64
SHEETS
OS. ARMY ENGINEER DISTRICT
LOS ANGELES
CORPS OF ENGINEERSo- 1887-8S
-1933-34
-1S60
-1^72
-March
Field Survey
Field Survey
Field Survey
Field Survey
Aerial
GENERAL NOTES:
Locations of roads, rivers, and waterfront structures are
approximate as digitzed from USGS Ouadrongle Maps.
Grid points are referenced to Lambert coordinates,
California Coordinate System, Zone 6.
A DB 1850 (typical): Location and designation of
CCSTWS benchmarks. M;RflpHlc aMfS w FffiT
COAST OF CALIFORNIA
STORM AND TIDAL WAVES STUDY
SAN OtECO REGION
HISTORIC SHORELINE POSITIONS
OCEANSIDE LITTORAL CELL
NOS SHORELINES 1887-1S82
MAP OS-13B
DATE
APPROVED:
T'SPEE.MO.OACWOT-
! 3:STH!CT FILE NO.
SHEET
42
OF