HomeMy WebLinkAbout; ; Semi-Annual Beach Profile Surveys & Analysis; 1993-10-01SEMI-ANNUAL BEACH PROFILE
SURVEYS AND ANALYSIS
APRIL 1993
SUBMITTED TO
CITY OF CARLSBAD
CALIFORNIA
SUBMITTED BY
TEKMARINE, INC.
ARCADIA, CALIFORNIA
OCTOBER 1993
EXECUTIVE SUMMARY
April 1993 Profiles
The April 1993 profiles in Carlsbad did not indicate signs of severe erosion or accretion, and
appeared to have remained within the general range of historical profile fluctuations known
in this region.
Volumetric Changes
Beach volume has improved steadily in recent years both above and below MLLW. In the
entire profile combining both above and below MLLW, the City-wide beach volume to -30
ft MLLW has gained more than 50 cy/ft over the initial April 1988 volume. This gain
corresponded to a total volumetric increase of about 1.5 million cy for the entire Carlsbad
coastline, eclipsing the 1.4 million cy gain achieved as of October 1992.
Shoreline Positions
There has been no significant trend for shoreline retreat in recent years. Changes in shoreline
position have been associated mainly with seasonal beach cycles.
Effects of Beach Nourishments
1. The effect of the 1988 beach nourishment by SDG&E was not clearly reflected on the survey
data, and this might be due to the fact that the pre-nourishment shoreline had been set back
severely by the historical January 18, 1988 storm which occurred just prior to the
nourishment.
2. The more recent 1991 SDG&E beach nourishment resulted in increased beach widths south
of the Agua Hedionda Lagoon entrance where the bulk of the available sand was placed.
3. We believe that the Corps of Engineers beach nourishment programs at Oceanside Harbor will
continue to exert little beneficial effects on the Carlsbad coastline because of the two
inadequacies characterizing these programs: the short discharge distance of the spoils and the
unfavorable timing.
Corps of Engineers CCSTWS Final Report
1. The report recognized the occurrence of downcoast sediment starvation which has resulted
from construction of the Oceanside Harbor, but did not specify the extent of the coastline
thus impacted.
2. The report also stated that the beach nourishments have mitigated the negative impacts of the
construction of the Oceanside Harbor, but partially.
3. Stressing that the future fate of the Carlsbad coastline will depend primarily upon the extent
of beach nourishment that would be performed, the report predicted different rates of future
beach erosion that would occur for Carlsbad as a function of the ratio of the future
nourishment compared to the past nourishment effort + 0.25 ft/year for a 100% nourishment
effort, -1.00 ft/year for a 50% nourishment effort, and -2.00 ft/year for a 25% nourishment
effort.
Kev Elements of Coastal Processes in Carlsbad
1. Carlsbad has the least amount of sand cover in its beach profiles in the entire Oceanside
Littoral Cell, as well as the least amount of beach widths. The narrow beach widths which
characterize the Carlsbad shoreline are essentially the result of sediment starvation in this
region.
2. Shoaling at Oceanside Harbor removes a very large proportion of littoral drifts converging
from both north and south of the harbor. The south fillet, which terminates at Wisconsin
Avenue, receives its sediment supply from beaches further south, possibly including beaches
in Carlsbad. Convergence of littoral drifts on Oceanside Harbor removes as much as 300,000
cy/year on the average, while the net natural littoral transport rate in the region is rated at
only about 100,000 to 250,000 cy/year.
3. Longshore currents in this region reverse themselves on a seasonal basis: the currents move
northward during June through September and southward during December through April.
The months of May, October and November are the period of transition.
4. Closure depths in the Oceanside littoral cell are known to be approximately 20 to 25 ft below
MLLW. However, extreme waves would cause changes to the profile much farther out than
these depths.
.«*
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY i
TABLE OF CONTENTS iii
LIST OF FIGURES iv
1. INTRODUCTION 1
2. LOCAL COASTAL PROCESSES BY CORPS OF
ENGINEERS CCSTWS 1
3. KEY ELEMENTS OF COASTAL PROCESSES
IN CARLSBAD 2
4. SURVEY RESULTS 3
4.1 The Data 3
4.2 Profile Changes 4
4.3 Volumetric Changes 4
4.4 Shoreline Positions 12
4.5 Effects of Beach Nourishments 15
5. CONCLUSIONS 16
APPENDIX A: Local Coastal Processes by Corps of Engineers Coast of
California Storm and Tidal Wave Study (CCSTWS)
APPENDIX B: Key Elements of Coastal Processes in Carlsbad
APPENDIX C: Beach and Nearshore Profiles to April, 1993 (Wading Profiles)
APPENDIX D: Entire Profiles to April, 1993 (Wading + Boat Profiles)
APPENDIX E: Time History of MLLW Shoreline Position to April, 1993
APPENDIX F: Beach Profile Survey Method
m iii
m
LIST OF FIGURES
m
m
m
a
Figure No. Page
4-1 Survey stations 5
4-2 History of profile changes above MLLW and nearshore depths
to April 1992 for selected stations 6
4-3 History of profile changes for the entire profile
to April, 1993 for selected stations 7
4-4 Definition of beach volume 8
4-5 Beach volume above MLLW 9
4-6 Beach volume below MLLW 10
4-7 Beach volume in the entire profile 11
4-8 Historical shoreline positions north of
Agua Hedionda Lagoon, Carlsbad 13
4-9 Historical shoreline positions south of
Agua Hedionda Lagoon, Carlsbad 14
BEACH SURVEYS AND ANALYSIS
CARLSBAD, CALIFORNIA
APRIL 1993
1. INTRODUCTION
The semi-annual Beach Survey and Monitoring Program in Carlsbad began in September,
1987. The beaches in Southern California have been known for their contrasting seasonal behavior
consisting generally of accretional summer profiles and erosional winter profiles. For this reason,
the two semi-annual surveys were typically performed in the months of April and October, the
former to recognize the impact of the winter storm season and the latter the impact of the summer
season.
This is the 12th semi-annual report which describes the survey data obtained in April, 1993.
The following list includes all the surveys completed thus far. Report No.2 included the data of the
emergency surveys conducted in the aftermath of the historical January 18, 1988 storm.
Report No. Date of Survey
1 September 1987
2 January, April 1988
3 October 1988
4 April 1989
5 October 1989
6 April 1990
7 October 1990
8 April 1991
9 October 1991
10 April 1992
11 October 1992
12 April 1993
2. CORPS OF ENGINEERS COAST OF CALIFORNIA STORM AND TIDAL WAVE STUDY
The long-awaited final report of the U.S. Army Corps of Engineers CCSTWS (Coast of
California Storm and Tidal Wave Study) report was published in September 1991. Excerpts from this
document relating to Carlsbad are summarized in Appendix A. Key elements of these excerpts are
summarized in this chapter.
m
m
Impacts of Oceanside Harbor
The report admits that the construction of Oceanside Harbor has interrupted the passage of
littoral material, contributing to the erosion which has occurred on the downcoast beaches. However,
it avoids to answer the key question as to how far downcoast this impact has extended. The report
also states that the trend toward erosion downcoast of Oceanside Harbor has been partially offset by
large quantities of artificial nourishment. Use of the word partially is justified here, since, although
the beach nourishment essentially returns the sand to the beach where it had originated, it may not
necessarily restore the beach to its original state.
State of the Beach at Carlsbad
Changes in the shoreline position at Carlsbad have been minor since 1940. However, during
the recent decade, the Carlsbad shoreline experienced moderate erosion ranging from 1.6 ft/year at
the south end of the city to 10 ft/year at the north end.
Future Erosion Potential
Shoreline change rates were predicted on the basis of three different levels of future beach
nourishment scenarios: 100%, 50% and 25% of the historical nourishment effort over the past 50
years. The predicted shoreline changes for Carlsbad are:
Nourishment Level Predicted Shoreline
% Change Rates ft/yr
100 + .25 ft/year
50 - 1.00 ft/year
25 - 2.00 ft/year
™ 3. KEY ELEMENTS OF COASTAL PROCESSES IN CARLSBAD
m
H Significant data and information on the beach processes in Carlsbad derived from the ongoing
Carlsbad Beach Monitoring Program are summarized in Appendix B. This chapter presents a brief
summary of this information.
m State of the Beach
Hi Sediment cover on the beach profile is extremely thin in Carlsbad. Both the minimum sand
cover and minimum beach widths in the entire Oceanside littoral cell occur in Carlsbad.
Impacts of Oceanside Harbor
Beach sediment converges toward the Oceanside Harbor not only from the shoreline to its
north, but also along the shoreline of its south fillet. The south fillet terminates at Wisconsin Avenue,
and any sediment added to this fillet is likely to head back to the Oceanside Harbor. The persistence
presence of the south fillet suggests that it is nourished by the feeder beach to its south which
includes the whole South Oceanside beach front and even some segment of the Carlsbad coastline.
Sediment convergence at the Oceanside Harbor removes a very large proportion of littoral drifts
available on the natural shoreline. It removes as much as 300,000 cy/year on the average, while the
net littoral transport rate in the region is rated at only about 100,000 to 250,000 cy/year.
Seasonal Reversal of Longshore Current
Based on factual measurements, the longshore currents along the Carlsbad shoreline are known
to undergo seasonal reversal, moving northward in summer (June through September) and southward
in winter (December through April).
Changes in Beach Profile
The so-called closure depth, i.e. the offshore limit of profile changes, is only about 20 to 25
ft (MLLW) in the Oceanside littoral cell. However, this concept is valid only under the normal wave
climate. Profile changes under extreme wave conditions will extend far beyond the so-called closure
depth. The profiles also tend to assume distinct seasonal configurations in response to the distinct
summer and winter wave climates in this region which cause onshore sediment transport in the
summer season and offshore transport during the winter season. However, the seasonal cycle will
manifest only on those profiles containing adequate amounts of sediment, either sand or cobble.
4. SURVEY RESULTS
4.1 The Data
The survey data obtained for April 1993 are presented in graphical format in comparison with
all the previous surveys in Appendices C, D, and E of this report, as follows:
Appendix C Beach and nearshore profiles to April 1993 (Wading profiles)
Appendix D Entire profiles to April 1993 (Wading + Boat profiles)
Appendix E History of MLLW shoreline positions to April 1993
i
The beach profile survey method is presented in Appendix F.
4.2 Profile Changes
The locations of the survey stations are shown in Figure 4-1. Figures 4-2 and 4-3 show,
respectively, nearshore and entire profiles at four selected stations (Morse Avenue, Tamarack
Avenue, Encinas Creek, and Batiquitos Lagoon). All the historical April profiles dating back to 1988
are shown to allow mutual comparison in these figures.
As shown in Figures 4-2 and 4-3, the April 1993 profiles in Carlsbad did not reveal any
significant trend for erosion or accretion. They all appeared to have remained within the general
range of historical profile fluctuations known in this region.
Being the product of the winter storm season just past, the April 1993 profiles revealed
evidence of a bar, generally located at 100 to 200 ft off the MLLW shoreline. The bar was more
conspicuous than in a year-ago data, suggesting that the beach profiles may have gained a greater
degree of normalcy since then. The bar was found at all the survey stations except at Tamarack
Avenue, the place known for deficiency of sediment.
Range of profile fluctuation is another indicator for the normalcy of beach profiles as the
profile fluctuation is inherently related to the availability of sediment in the profile. The range of
profile fluctuation will be small in profiles with sediment deficiency and large in profiles with
sediment abundance. In the April 1993 survey, Tamarack Avenue, known for its minimum sediment
content in the profile in Carlsbad, was again the locus of minimum range of profile fluctuation.
Range of profile fluctuation increased with distance north and south from this location reflecting the
increase in the amount of sediment in the profile in both directions. The range of profile fluctuation
was at its maximum in the cobble-dominated profile at Batiquitos Lagoon, and was also quite large
in the sand-dominated profile at Morse Avenue, Oceanside.
4.3 Volumetric Changes
Beach volume in the profile, derived from the survey data, has been determined using a
planimeter. Beach volume, defined in Figure 4-4, represents the volume of the beach configuration.
not the volume of sediment in the profile. In this report, beach volume is measured from either the
landward end of the berm or a 15-ft elevation (MLLW), whichever is nearer the shoreline, to a water
depth of -30 ft (MLLW), over a 1-ft length of shoreline, expressed in cubic yards/foot of shoreline.
Whereas the beach volume is not necessarily related to sediment volume, changes in beach volume
with time are, since they are the result of gain or loss of sediment in the profile,
Historical beach volume data are summarized in Figures 4-5, 4-6, and 4-7. City-wide
average beach volume above MLLW is plotted in Figure 4-5; City-wide average beach volume below
MLLW in Figure 4-6; and City-wide average beach volume for the entire profile (combining both
the above and below MLLW volumes) in Figure 4-7.
LEGEND:
CI-0720 RANOE LINE NUMBER
A WADINQ SURVEY
• WAOINQ AND (OAT SURVEY
H.CIHC OCCAM
CB-O7ZO
• CB-0760
Ca-0740
m
m
Figure 4-1. Survey stations.
ft J ft 1 •JKIKI*lllIiI1flfllllllli«*lKflil11
100 200 300 400 500 600 700 100 900 1000 C 100 200 HO 400 MO MO 700 100 900RANGE (feet seaward of rangi line monument) RANGE (feat eeaward of range line monument), i I i i , i i i i , , I , i t , I , , , i I ,
200 300 400 300 (00 700 900RANGE (feet seaward of range line monument)900 1000 200 300 400 300 600 700 MORANGE (feat seaward of range Una nonument)
Figure 4-2 History of profile changes above MLLW and nearshore depths to April 1993
for selected stations
• • I II • I • I II I 1 I ! r 1 f I I 1 II i 1 II •!1 II i «
1300 2000 2300 9000 3500 4000 4500
RANGE (feet seaward of ranae i\n* monument.)
1000 1500 2000
RANGE (feet seaward of ranae line monument)
1000 1500 2000
RANGE (feet seaward of range line monument)
1000 1900 2000
RANGE (ftet seaward of range line monument)
Figure 4-3 History of profile changes in the entire profile to April 1993 for selected
stations
DEFINITION
OF BEACH VOLUME
BLUFF
EXCLUDED
+15
VOLUME ABOVE MLLW
DISTANCE OFFSHORE
VOLUME BELOW MLLW
-30 -CLOSURE
DEPTH
H
m
VOLUME jt SEDIMENT
Figure 4-4 Definition of beach volume
m
K 1 I i I ft I II ft I II II II r 1 fl II • !* • 1 • • i • •
Date 1: Above Mean Lower Low Water (MLLW)
LINE
960
930
880
850
840
830
820
780
760
740
720
SEP '87
40.1
80.6
49.1
34.3
27.6
26.5
61.9
36.6
34.6
29.2
103.9
AVERAGE 47.4
APR '88
34.0
52.6
30.4
25.7
38.7
34.8
55.3
28.3
21.9
. 16.8
78.5
37.9
OCT'88
54.9
74.7
51.1
57.3
27.8
30.9
58.5
48.2
37.0
23.0
93.2
50.5
APR '89
53.1
67.2
44.4
25.7
33.1
29.9
45.9
33.1
31.8
15.7
78.5
41.7
MONTH AND
OCT'89
48.8
73.5
54.5
52.3
26.1
49.4
48.7
50.6
33.6
24.2
86.8
49.9
YEAR
APR '90
51.9
64.9
48.5
34.3
31.5
37.0
43.1
35.1
29.6
16.8
77.9
42.8
OCT'90
53.1
75.4
53.7
49.7
29.3
22.7
40.4 •
33.7
31.3
31.4
84.0
45.9
APR '91
46.3
61.9
40.9
37.7
15.5
29.3
64.1
19.3'
22.4
20.2
82.9
40.0
OCT'91
51.9
75.1
59.6
66.9
38.7
33.2
70.8
26.0
34.6
31.0
91.2
52.6
APR '92
39.5
67.8
35.3
46.0
36.4
27.8
76.5
43.1
26.0
21.3
80.2
45.4
OCT'92
49.4
80.6
53.6
63.3
28.1
34.2
77.3
41.3
35.8
25.4
93.3
52.9
APR '93
41.8
65.0
51.5
42.3
25.4
39.6
70.6
38.5
20.6
20.2
80.8
45. 1
UNIT: CUBIC YARDS/FT.
55
,. 50
45
I40
35
1987
LEGEND
•FALL
• SPRING
Data 1: Average Volume
OCTOBER
1988 1989 1990
YEAR
1991 1992 1993
Figure 4-5 Beach volume above MLLW
I if 1 i II 11 II 11 II ri II VI II ft! • • II VI *
Dafa2; Below Mean Lower Low Water (MLLW)
LINE
930
830
820
760
720
SEP '87
1086.4
1077.4
1117.9
1077.4
1177.8
AVERAGE W 1103.8
AVERAGE !2> 1098.5
APR '88
1333.3
1075.0
1133.5
1026.9
1012.4
1115.4
1107.3
OCT'88
1183.8
1081.3
1094.6
1045.0
1097.6
1094.2
1091.6
APR '89
1348.2
1104.4
1114.5
1104.4
988.7
1125.9
1121.5
MONTH AND
OCT'89
1142.0
1084.6
1041.7
1111.1
1070.7
1080.3
1081.1
YEAR
APR '90
1400.0
1090.9
1047.1
1107.7
972.2
1120.8
1114.8
OCTW
1363.0
1043.8
1007.7
1084.2
925.9
1084.1
1076.0
APR -91
1348.2
1104.4
1165.0
1026.3
978.4
1129.5
1124.4
OCT91
1229.6
1060.6
1124.6
1016.2
972.2
1085.7
1080.6
APR '92
1259.3
1090.9
1148.2
1053.2
1121.2
1145.5
1134.5
OCT'92
1185.2
1053.7
1122.2
1059.3
1140.8
1126.9
1112.2
APR '93
1305.6
1052.6
1150.3
1041.5
1125.8
1155.9
1135.2
UNIT: CUBIC YARDS/FT.
LEGEND
•FALL
• SPRING
Data 2: Average'1' Volume
1160
1150
1140
1130
1120
1110
1100
1090
1080
1070
1987 1988 1989 1990
YEAR
1991 1992 1993
(1): A verage of 4 lines, excluding Line 830 which Is too close to line 820. (2): A verage of all 5 lines
Figure 4-6 Beach volume below MLLW
ft I ft I ft I ft i ft J ft i • I 1 i I 1 II f I II B 1 B • B 1 Bl II B 1 II
LEGEND
1205.0
1195.0
113S.O
1125.0
1987
•FALL
• SPRING Entire Profile
(Datal + Data 2)
1988 1989 1990
YEAR
1991 1992 1993
Figure 4-7 Beach volume in the entire profile
m As shown in Figure 4-5, the April 1993 beach volume above MLLW in Carlsbad nearly
„„ equaled the all-time high April volume achieved in 1992. The April beach volume above MLLW has
m been consistently lower than the October volume above MLLW by an average margin of about 10
cy/ft. This situation reflects the well-known seasonal beach cycle in Southern California in which
m the subaerial beach (above MLLW) accretes in summer and erodes in winter.
•^^a The April beach volume below MLLW (to a depth of -30 ft) has improved steadily in recent
m years, as shown in Figure 4-6, leading to a historical high as of April 1993. Figure 4-6 also reveals
ID that the beach volume below MLLW has been distinctly lower in October than in April in any given
year, suggesting that the pattern of profile change below MLLW was a reversal of the pattern above
MLLW, i.e., that the profile below MLLW eroded when the profile above MLLW accreted, and vice
H versa.
m However, there was a greater loss below MLLW than accounted for by the recorded gain
m above MLLW. Namely, the amount of loss below MLLW from April to October was, say, about 30
cy/ft, while the amount of gain above MLLW during the same period was only about 10 cy/ft. This
meant that a margin of about 20 cy/ft had escaped from below MLLW elsewhere, very likely into
the deeper water across the 30-ft depth contour. The existence of such an active migration of
M sediment across the 30-ft contour suggests that for the purpose of evaluating a sediment budget, the
in closure depth must be expanded further offshore than the normally accepted depths of 20 to 25 ft
(MLLW).
In Figure 4-7 which shows the history of the beach volume in the entire profile combining
both above and below MLLW, the April 1993 beach volume for the entire profile achieved a new
"* historical high for this season, exceeding the initial April 1988 volume by 47.7 cy/ft. Assuming a
** similar average gain per profile over the entire Carlsbad coastline, the total gain to April 1993 within
^ the City boundary since 1987 would be about 1.5 million cy. This is similar to the 1.4 million cy of
m City-wide gain which was previously estimated based on the October beach volume data to October
1992.
1-111 4.4 Shoreline Positions
m
M The historical shoreline positions to April 1993 are summarized in Figures 4-8 and 4-9, the
former for the stretch from Oceanside Boulevard to Tamarack Avenue and the latter for the stretch
from Agua Hedionda South Beach to Batiquitos Lagoon. The April beach width is typically narrower
than that for preceding October because of the seasonal beach cycle, and may therefore tend to give
m a false impression of erosion. Keeping this in mind, we find no alarming trend for shoreline retreat
It in the April 1993 data. The beach cycle, consisting of advancement in the summer and retreat in
the winter, appeared most evident near the northern and southern boundaries of the city where there
are sizable amounts of sediment in the profile. Seasonal beach cycle alone was responsible for
m
m 12
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Figure 4-8 Historical shoreline positions north of Agua Hedionda Lagoon, Carlsbad
J 11 11 11 11 II fi fl If II II II 1111 tl f 1 II II
AGUA HEDIONDA SOUTH POINSETTIA LANE
Sltonllni PotUai (flj: UM 121 Mgu HxftmJi South
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UOHTM AND IXU
Figure 4-9 Historical shoreline positions south of Agua Hedionda Lagoon, Carlsbad
responsible for changes in shoreline position of about 100 ft at Buena Vista Lagoon and about 125
ft at Batiquitos Lagoon.
4.5 Effects of Beach Nourishments
Indications of the effect of the SDG&E beach nourishment on shoreline position were mixed.
Between February and April, 1988, a total of 334,000 cy of sand dredged from Agua Hedionda
Lagoon was placed on the adjacent beaches. Of this amount, 151,000 cy was placed over a distance
of 2,100 ft north of the lagoon entrance, including Stations CB-830 (Tamarack Avenue) and CB-
840 (Acacia Avenue), while the remainder, 183,000 cy, was placed over a distance of 4,500 ft south
of the lagoon entrance, including Station CB-820 (Agua Hedionda South). As shown in Figures 4-
8 and 4-9, the effect of this nourishment program on the shoreline position was not quite revealing;
there was a slight advancement of shoreline in the October 1988 survey at Agua Hedionda South but
not at either of the two other nourished stations, Tamarack and Acacia Avenues. We believe that
the nourishment of February-April 1988 did little more than restoring the sediment loss which had
resulted from the devastating January 18, 1988 storm.
The most recent nourishment project took place during December 1990 and April 1991, in
which the bulk of the sand was placed south of the lagoon entrance; of the 465,000 cy of sand,
415,000 cy was placed south of the lagoon entrance, and only about 50,000 cy to the north. As shown
by the post-nourishment survey (October 1990) in Figure 4-9, the shoreline at Agua Hedionda South
(CB-820) achieved a historical high, the direct result of the large amounts of sand placed on this
beach, indications of shoreline advancement were also revealed, although to a much lesser extent,
at Acacia Avenue (CB-840) as well, but barely at Tamarack Avenue (CB-830), both located north
of the lagoon entrance.
Two other beach nourishment programs were undertaken at a remote location, Oceanside
Harbor, by the U.S. Army Corps of Engineers, involving 217,000 CY between April through mid-
June, 1989 and 250,000 CY in August, 1990. In these Corps of Engineers programs, sand was
dredged from the Oceanside Harbor entrances and discharged at Tyson Street, only 1.5 miles
downcoast of the harbor. The discharge location is part of the south fillet for the Oceanside Harbor,
and it is unlikely that the sand placed here could have migrated southward to reach the Carlsbad
coastline in any sizable amounts. The fact that the timing of the dredging operations in both cases
coincided with the time of the northward reversal of longshore currents reinforce this view. We
believe that the routine disposal practices in the Corps of Engineers beach nourishment program at
Oceanside, characterized by the short disposal distance and the unfavorable timing, will result in little
beneficial effects on the Carlsbad coastline.
m
m 15
5. CONCLUSIONS
Corps of Engineers CCSTWS Final Report
1. The report recognized the occurrence of downcoast sediment starvation which has resulted
from construction of the Oceanside Harbor, but did not specify the extent of the coastline
thus impacted.
2. The report also stated that the beach nourishments have mitigated the negative impacts of the
construction of the Oceanside Harbor, but partially.
3. Stressing that the future fate of the Carlsbad coastline will depend primarily upon the extent
of beach nourishment that would be performed, the report predicted different rates of future
beach erosion that would occur for Carlsbad as a function of the intensity of beach
nourishment.
Kev Elements of Coastal Processes in Carlsbad
1. Carlsbad has the least amount of sand cover in its beach profiles in the entire Oceanside
Littoral Cell, as well as the least amount of beach widths.
2. The narrow beach widths which characterize the Carlsbad shoreline are essentially the result
of sediment starvation in this region.
3. Shoaling at Oceanside Harbor removes a very large proportion of littoral drifts available on
the natural shoreline. It removes as much as 300,000 cy/year on the average, while the net
natural littoral transport rate in the region is rated at only about 100,000 to 250,000 cy/year.
4. We believe that littoral drifts converge on the Oceanside Harbor from both north and south.
The 1.5-mile long south fillet at Oceanside Harbor is considered to maintain its existence at
the expense of a rivetted 2-mile beach to its immediate south which functions as a feeder
beach for the fillet. We suspect that an unspecified length of the Carlsbad shoreline further
to the south may also function as a feeder beach for the Oceanside south fillet, provided that
this function is obscured by the local sediment accretion in the lee of a natural kelp bed which
exists offshore.
5. Seasonal reversal of longshore currents along the Carlsbad coastline is a fact well established
by the Corps of Engineers survey data. The longshore currents directed northward during
June through September and southward during December through April. The months of May,
16
** October and November are the period of transition.
^ 6. The well-known seasonal beach cycle in this region is caused by the distinct seasonal wave
climate in summer and winter, and involves net shoreward sediment migration in the profile
during in summer and seaward migration in winter. Only recently have the profiles in
** Carlsbad begun to exhibit the seasonal cycle.
m
m 7. Closure depth, i.e. maximum depth of profile changes under a normal wave climate, is
— approximately 20 to 25 ft below MLLW. However, extreme waves would cause changes to
the profile much farther out than the closure depth.
m Aoril 1993 Profiles
m 1. The April 1993 profiles in Carlsbad did not indicate signs of severe erosion or accretion, and
appeared to have remained within the general range of historical profile fluctuations known
in this region. Beach profile fluctuations have been mainly associated with seasonal beach
cycles.
M 2. Beach profile fluctuations were large in the sediment-rich areas both near the northern and
southern boundaries of the City, and small where sediment was scarce, particularly at
Tamarack Avenue.
*M
""• Volumetric Changes
kM
^ 1. Beach volume has improved steadily in recent years both above and below MLLW. In the
entire profile combining both above and below MLLW, the City-wide beach volume to -30
ft MLLW as of April 1993 has gained nearly 50 cy/ft over the initial April 1988 volume. This
"" gain corresponded to a total volumetric increase of about 1.5 million cy for the entire
•" Carlsbad coastline, eclipsing the previous gain of 1.4 million cy as of October 1992.
— 2. Averaged over the City coastline, about 10 cy/ft of sediment migrated from above to below
MLLW from October to April. Also during the same period, the profile below MLLW (to -
* 30 ft) gained an additional amount of about 20 cy/ft, which very likely migrated from the£l
deep water beyond the -30 ft (MLLW) depth contour. This trend was reversed from April
«, to October, suggesting that it was a seasonal phenomenon.
m
3. In light of the seasonal migration of large amounts of sediment across the -30 ft depth
contour, we believe that a closure depth must be extended beyond the usual 20 to 25 ft depth
M range for the purposes of sediment budget analysis.
* 17
Shoreline Positions
1. There has been no significant trend for shoreline retreat in recent years. Changes in shoreline
position have been mainly associated with seasonal beach cycles.
2. Seasonal cycles were most prominent in the two sediment-rich areas near the northern and
southern boundaries of the City. The widths of seasonal shoreline fluctuation amounted to
about 100 ft in the northern stretch and about 125 ft in the southern stretch.
Effects of Beach Nourishments
1. The effect of the SDG&E's 1988 beach nourishment was not clearly recognized in the survey
data, and this may be due to the fact that the pre-nourishment shoreline had been set back
severely by the historical January 18, 1988 storm which occurred just prior to the
nourishment. The more recent 1991 beach nourishment by SDG&E resulted in a historically
high beach width south of the Agua Hedionda entrance where the bulk of the available sand
was placed, but in insignificant advancement of shoreline north of the lagoon entrance where
the amount of sand placement was minor.
2. We believe that the Corps of Engineers beach nourishment programs at Oceanside Harbor will
continue to exert little beneficial effects on the Carlsbad coastline because of the two
inadequacies which characterize these programs: the short discharge distance of the spoils and
the unfavorable timing.
18
Appendix A
LOCAL COASTAL PROCESSES BY CORPS OF ENGINEERS CCSTWS
m
m
LOCAL COASTAL PROCESSES BY CORPS OF ENGINEERS CCSTWS
The long-awaited final report of the U.S. Army Corps of Engineers's CCSTWS (Coast of
California Storm and Tidal Wave Study) was finally published in September 1991. This report is of
special interest to us, since it represents the latest official view of the coastal processes for our region.
£ This appendix summarizes excerpts contained in this report relating to Carlsbad.
m On Shoreline Changesm
m "•— The construction of Oceanside Harbor has interrupted the passage of littoral material,
H contributing to the erosion which has occurred on the downcoast beaches. Conversely, this trend
toward erosion has been partially (the underline added) offset by large quantities of artificial
nourishment. Significant sources of such nourishment material have included Oceanside HarbormAgua Hedionda Lagoon, and the San Onofre Nuclear Generating Station site." (Pages x and xi)
«• (Tekmarine comments: Sand used for nourishment from these three sources had originated
from the very littoral zones which were later nourished. Although the sand is thus returned to
its original source, the nourishment operation does not guarantee that the sediment budget will
be restored, thus the use of the qualifying word "partially."
*• "It is anticipated that the condition of the beaches in the future will be governed by cycles
^ of accretion and erosion similar to those of the past 50 years, but with accelerated trends toward
erosion because of the following conditions: 1) the reduction in river-borne sediment due to
impoundment by dams, 2) the influence of Oceanside Harbor, and 3) the increase in the rate of sea
™ level rise." (Page xi) (Underline added.)
m
m "The most critical coastal reach in terms of susceptibility to future erosion is the 12-mile
g[ stretch of beach south of Oceanside Harbor (which will include the entire Carlsbad shoreline -
Tekmarine). Between 1980 and 1989, the Mean Higher High Water (MHHW) shoreline immediately
south of the harbor retreated at a rate of approximately 40 ft/yr. The rate of retreat decreased withgl
increasing distance to the south, averaging approximately 5 ft/yr at Agua Hedionda and 1 ft/yr at
m Encinitas. Factors contributing to this erosional trend appear to be the cluster storms of 1982-1983,
gfl and the reduced rate at which artificial nourishment material has been supplied. The provision of
increased quantities of nourishment material will be of critical importance in stabilizing these
downcoast beaches." (Page xi)
m
m.
"Carlsbad Subreach (Mile 47-53)
Since early 1940, changes in the MHHW shoreline in this six miles reach have been minor
with occasional small accretions (see Figure 3-6a - excerpted on page 4.). During the period
1980-1989, this subreach has experienced moderate erosion ranging from 1.6 ft/year at Mile
49 to 10 ft/year at Mile 53. (Page 3-21) (Tekmarine comments: Miles are counted northward
from the US-Mexican border.)
On Impacts of the January 1988 Storm
"By November 1989, most of the San Diego Region shoreline seemed to have recovered (net
accretion of about 25 ft above the September 1987 shoreline) from the January 1988 storm erosion
with the exception of the Imperial Beach area (Mile 3), Carlsbad and the south beaches of Oceanside
(see subreaches III and IV of Figure 3-27a - listed on the following page) where a net average erosion
of approximately 15 feet was estimated." (Page 3-52)
On Predicted Shoreline Changes
"Based on the assumption that the future climate (1989-2010) will resemble that which has prevailed
during the past 50 years, it appears that the most important factor, which could impact San Diego's
• future shoreline, is the intensity of future sand nourishment activities. Therefore, any suggested
scenarios for predicting the future shoreline positions should consider future variations in the
amounts and rates of sand nourishments along the 3 San Diego littoral cells."
"The following three scenarios are examples of a methodology which could be used for predicting
future shoreline change for the San Diego Region.
Scenario 1: Sand nourishment will continue through the year 2010 at the same average annual rates
and locations which took place during the period 1940-1989.
Scenario 2 and 3; The nourishment rates will be reduced by 50 and 25 percent respectively.
These two scenarios are important in assessing the impact of future reduction in nourishment rates
on possible shoreline retreat at key coastal location."
The results of the above suggested approach to predict the approximate future shoreline changes to
the year 2010 for the San Diego region's three man (main?) cells ate (are?) shown in Figures 3-21.
3-22, and 3-23 (Silver Strand, Mission Bay and Oceanside).
The main results at Key Location are summarized in Table 3-8. The data presented in Table 3-8
should be used with extreme caution and their application should be limited as guidelines for
reconnaissance planning and development scenarios." (Page 3-62, 63)
(ft/yr)OCEANSIDE LITTORAL CELL
RATE OF SHORELINE MOVEMENT
•frHWK; /=>rr==
(••la MirjtrlU
Xlrtr
30 35 40 45 50 55 60 65 70 75 80I »i J3J.('LJ(.(3i -J- £i -I- 0 .L <«)-
OCEANSfflE SUB REACHES
m
FIGURE 3-63 SHORELINE RATE OF MOVEMENT
OCEANSIDE CELL
Figure CCSTWS 3-6a (Page 3-23)
Table CCSTWS 3-5 (Page 3-25)
*l
tf
LOCATION
LJ 443
LJ 445
LJ 450
LJ 460
TP 470
TP 520
TP 530
TP 540
DH 560
DH 580
DM 590
SO 600
SD 630
SO 670
CB 720
CB 760
CB 800
CB 830
OS 900
OS 930
OS 1000
OS 1030
OS 1070
PN 1080
PN 1110
PN 1180
PN 1240
PN 1280
PN 1290 .
SO 1340
SO 1470
SO 1530
SC 1623
SC 1660
SC 1680
SC 1720
DB 1805
DB 1850
DB 1895
DB 1900
MHHW SHORELINE CHANGE RATE (ft/yr)
pre 40 's 1940- 1960- 1980-
1960 1980 1989
La Jol la-Del Mar Sub Reach
1.00 -1.00 1.20 5.50
-1.50 1.40 -1.50 -4.10
0.50 0.80 -2.00 7.80
1.00 -0.10 -1.60 8.10
3.00 2.60 -0.30 13.80
0.50 0.80 -0.80 4.70
1.00 1.60 -4.30 5.10
2.00 0.70 0.00 5.90
. 1.50.. -0.60 . 0.70 0.90
2.50 0.00 -0.40 3.50
4.00 -2.20 8.50 28.00
Encinitas-Leucadia Sub Reach
1.00 -1.30 0.10 -0.70
1.00 -1.50 1.30 0.90
2.00 -1.90 3.20 -3.10
-1.00 1.10 0.00 -0.90
Carlsbad Sub Reach
0.50 0.00 1.00 -1.60
-1.00 2.60 4.30 -2.60
-1.00 4.80 0.00 -6.50
0.00 0.00 0.00 -9.90
Oceanside Sub Reach
-0.50 -0.70 2.60 2.00
3.00 -3.70 0.00 -4.00
4.00 -6.70 2.40 -14.00
4.00 -5.20 9.00 -33.40
4.00 13.90 3.50 -30.60
4.00 6.11 1.38
3.00 5.40 0.20 -0.10
Camp Pendleton Sub Reach
-1.00 3.30 0.00 15.60
-1.00 7.00 -1.00 4.20
0.00 1.50 -1.40 -2.00
0.00 3.00 -0.20 3.70
0.00 1.10 2.00 6.00
-0.50 -1.10 1.20
San Mateo-Dana Point Sub Reach
-0.20 -0.70 7.10
0.00 0.60 -2.00
2.50 -0.40 1.40
0.00 0.00 4.80
-1.90 8.10 -12.30
-0.60 9.30
2.50 -0.40 -0.50
0.00 -1.90 -10.00
MAX SEASONAL
NHHU MOVEMENT (ft)
SUMMER
12.7
41.4
73.2
74
77.9
47.4
79.1
43
41.6
93.4
23.1
53.2
72
58
37
5.1
20
85.3
44
34
46
60
140
96
340
107
37
23
12
24.9
35.5
34.7
25.4
17
45.5
30
25
2.7
24.6
59.8
WINTER
-13
-63.5
-21.8
-80.8
-147.5
-36.7
-80
-14
-49.5
-91.8
-90.8
-71.9
-110
-50
-39
-4.2
-20
-24.5
-59
-35
-106
-65
-55
-188.7
-82
-114
-12
-27
-37.9
-18.7
-25.3
-71.5
-26
-34
-57.4
-27
-45.6
-70.2
-31.4
-91.4
•II
IV
STORM INDUCED EROSION AND RECOVERY
RELATIVE VOLUME CHANGE [MSL] VS DISTANCE ALONG SHORELINE
( SEP 1987 BASELINE )
8O
—J- SEP 1907 TO NOV. 1989
OCEANSIDE SUB REACHES
V
5 1O 15 2O 25 3O 35 4O 45 5O 55 6O 65 7O 75 BO
MILAQE FROM U.S./MEXICAN BORDER
FIGURE 3-27a
m
m
m
Figure CCSTWS 3-27a (Page 3-54)
Table CCSTWS 3-7 (Page 3-56)
Ml
H
mm
TABLE 3-7
THE JANUARY 1988 STORM IMPACT
VOUME ( GAIN OR LOSS ) CD YD X 10
RELATIVE TO SEPTEMBER 1917 SURVEY
REACH
OR SUI-REACH
SILVER STRAND CELL
MISSION IAY CELL
OCEANS1DE CELL
Li Jol la-Del Mir
tub- retch
Enclnltit-Leucidli
tub- retch
Cirltbad
•ub-mch
Oceimlde
tub- retch
Cwp Ptndlitontub- retch
Sin Htteo-Dml Pt
tub-reich
TOTAL
REACH LENGTH
MILES *
11.15
3.2
9
6.6
1.1
5.2 .
9.3
7
52.55
JAN 1988
-1.85
-0.29
-1.0*
-O.M
-0.05
-0.85
-0.21
-0.12
-5.04
HOT 1989
1.29
0.15
0.41
-0.24
O.M
O.M
-0.20
-0.11
1.37
OBSERVATION
conplete recovery
conplete recovery
ccnplete recovery
pirttilly recovery
recovered
recovered
pirtlilly recovery
part III ly recovery
JAN 1988 STORM
EROSION
(CU YD/I In ft)
-31.39
-17.39
-21.88
-18.33
-9.23
-30.93
-*.36
-3.38
-18.2*
- Loll
* Limited by ivillibti ivirvey*
OCEANSIDE LITTORAL CELL
2010 Predicted MHHW Shoreline Position Change
£J ::n ~
... F.i.l
30 35 40 45 50 .55 (0 (5 70 . 75 80
(5)
OCEANSIDE SUt REACHES
Shoreline Position Difference
from 1989 Shoreline Position
to
FIGURE 3-31
Figure CCSTWS 3-31 (Page 3-64)
vu
Table CCSTWS 3-8 (Page 3-63)
Cell
Silver Strand
Table 3-8 Predicted Shoreline Position
Changes by the year 2010
MHHW Shoreline position change (1989-2010)
Location 100% nourishment 50%N.
Mission Bay
Oceanside
Tijuana River/ -15
Imperial- Beach
Coronado +200
Ocean Beach +20
Mission Beach +25
Carlsbad
(mile 47 - 53} +5
Oceanside, South
Beaches -50
-120
+30
0
+10
-20
-75
25%N.
-170
-50
-15
0
-40
-120
* - Erosion
* + Accretion
m
m
m
Vlll
(Tekmarine comments - The report does not show the method used for this prediction. Even
if the future climate (1989-2010) were the same as that during the past 50 years, the sequence
in which individual storms and climatic events would occur vary from the past and result in
producing quite different cumulative impacts on the shoreline than in the past. This has been
verified with numerical model experiments in which two climates, equivalent to each other in
an average sense but different in sequences of occurrence of individual events, resulted in
distinctly different shorelines. For this reason, these long-term predictions, should be
considered only of academic interest. Furthermore, the prediction does not show the so-called
accelerated trends towards erosion as asserted elsewhere in the report.)
"Summary and Conclusions
(3) Carlsbad Subreach (Mile 47-53)
Since early 1940, changes in the MHHW shoreline in this six-mile reach have been minor, with
occasional small accretions. During the period 1980 - 1989, this subreach experienced moderate
erosion ranging from 1.6 feet per year at Mile 49 to 10 feet per year at Mile 53." (Page 3-69).
IX
Appendix B
KEY ELEMENTS OF COASTAL PROCESSES IN CARLSBAD
«• KEY ELEMENTS OF COASTAL PROCESSES IN CARLSBAD
«*•
m This appendix summarizes significant data and information underlying the beach processes
unique to Carlsbad based on the data and observations from the ongoing Carlsbad Beach Monitoring
m Program.
m State of the Beach
m
Major landmarks along the coastline of the City of Carlsbad is shown in Figure B-l. The
indicated miles from Oceanside Harbor show that the Carlsbad shoreline starts only 3.7 miles south
jjH of the harbor and terminates at approximately 9.7 miles, approximately 6 miles long. According to
•» the U.S. Army Corps of Engineers CCSTWS system which uses miles northward from the U.S.-
m Mexican border, the Carlsbad shoreline is located between 47 and S3 miles.
Figure B-2 shows the-survey stations which are occupied for semi-annual beach surveys.
Two of these stations, OS-0960 and OS-0930, are located within the City of Oceanside as an outpost
to sense the impacts of any man-made changes occurring at the harbor, such as sand bypassing,
"" . dredging, and sand disposal on the beach.
*• Figure B-3 show thickness of sediment cover (consisting of both sand and gravel) and beach
^ widths in the Oceanside littoral cell. Table 1 consolidates the sediment thickness data based on the
jet probing surveys conducted by Tekmarine in 1987. It is evident that Carlsbad has the least amount
of sand cover in the entire cell, as well as the least amount of beach widths in the entire cell. An
"~" excellent parallelism between sand thickness and beach width as revealed in Figure B-3 indicates that
** the narrow beach widths which characterize the Carlsbad shoreline are essentially the result of
... sediment starvation in the region.
mm
Impacts of Oceanside Harbor
In Figure B-3, sand thickness falls sharply across Oceanside Harbor from the north to the
m south, suggesting that the large sand thickness north of the harbor may be related to the impounding
gtf of the southerly moving coastal sedimeni by the protruding breakwaters of the harbor. Furthermore,
the presence of a small but conspicuous fillet on the south side of the harbor suggests that sediment
converges on the harbor from the south as well as from the north. This explains the fact that the
shoaling rate at the entrance of Oceanside Harbor averaging 300,000 cy/year exceeds the net
m southerly transport ranging between 100,000 and 250,000 cy/year.
II Our field reconnaissance trips which have been continued since the fall of 1987 on a bi-
monthly basis have indicated that the south fillet of the Oceanside Harbor is only about 1.5 miles
^PB
^ long. At the terminus of the south fillet, the natural beach disappears abruptly and is replaced by
HI
m
m
m
OCEANSIDE
BATIQUITOS •**-:
LAGOON
CARLSBAD
NOTE: UNDERLINED NUMBERS DENOTE MILES SOUTH FROM OCEANSIDE HARBOR.
Figure B-l Carlsbad shoreline relative to Oceanside Harbor
11 BEST ORIGINAL
LEGEND:
CB-0720 RANOE LINE NUMBER
A WADINO SURVEY
• WAOINQ AND (OAT SURVEY
fACiriCOCtAH
• CB-O720
Figure B-2 Survey Locations
m
m
111
THICKNESS (FT)BEACH WIDTH [FT]
800 600 400 200 0
OFFSHORE BEACH
DOHENY
SAN ONOFRE
OCEANSIDE
HARBOR
BUENA VISTA
LAGOON
BATIQUITOS
LAGOON
- DEL MAR
LA JOLLA
TEKMARINE, INC.
Figure B-3 Sediment thickness and beach widths
IV
Table B-1 Sediment thickness data
SEDIMENT THICKNESS DATA
HANOI
Lilt
HOIK LOCATION SMID THICKNESS (FT)ro» FIOIE 10.
SITS DESOItTION
CB 130
C» 110
Cl 110
Cl DOct 130
Cl 1)0
OS fOO
03 100os tooos too
OS 100os too
os loioas 10)0
OS 10)0os 10)0
OS 10)0
OS 10)0
OS 1070os 1010
OS 1070
OS 1070
OS 1070
OS 1070
10/11/17
10/11/17
10/11/17
11/13/17
11/11/17
11/13/17
10/11/17
10/11/17
10/11/17
11/13/17
11/13/17
ll/D/17
10/11/17
10/11/17
10/11/17
11/K/I7
11/U/I7
11/K/I7
10/11/17
10/11/17
11/K/I7
11/1 (/I 7
11/K/I7
1
2
3
4
9
«
1
2
3
4
9
(
1a
3
4
9
(
i])
4
9
(
(ALL COBBLE)
(ALL jCOBBLS)
(JILL COI
104.1
10(9.1
1(12.1
4(.l
103. (
110.)
711.0
1109.0
2099.0
10.1
111.1
219.4
999.0
1)12.0
2422.0
(9.4
191.7
321.3
1)24.)
1111. 1
)44(.)
lit! I
-12.4
-11.4
-21.)
11. (
9.2
1.1
-19.9
-22.0
-12.0
D.4
10.2
2.9
-13.3
-20.)
-31.)
14.0
12.7
4.1
-12. (
-21.1
-31.1
0.0
0.0
0.0
0.0
0.0
0.0
7.J
1.2
1.1
20.0
4.1
3.0
11.9(.(
11.2
(.9
3.5
K.O
1.7
!.(__.»
1).)
20.0
0.0
0.0
0.0
0.0
0.0
0.0
7.2
7.1
(.2
20.0
4.1
3.0
11.2(.0
11.2
7.0
4.0
It.l
1.4
1.4
K.O
14.1
20.0
20.0
0.
0.
0.
0.
0.
0.
7.
1.1.
20.
4.
1.
11.
(.
11.
(.
1.
17.
1.
1.
1(.
14.
20.
20.0
ONSNOB.C - COBBLE BEACH WITH SANDSTONE OUTCIOM.
BACKED BX SEAWALL AND BLUFFS TO HOBTH XXD AQUA
HEDIONDA LAOOOM TO SOUTH.oFFSHoxz - XEEF ouxcaots i»xnj»t»»iD WITH SAID
CHANNELS. BOTTOM HILItf Of 2-3 FT. XELF BED AT
LOCATION MO. (.
OHSaOKK - VAX1OW SX»D BEACH BACKED BT KOCX IETST-
HEVT, LOW BLUrr AHD DWELLIIOS.
orrsuonx - SMOOTH SAMD >LAI* AT LOCATION >os. 4
AHD 9, SMOOTH SILT 7LAII AT LOCATION HO. (.
OHSHOXS - WIDE SAND BEACH BACKED BX LOW-LXINO
DEVELOPMENT AND HIGH BLUFFS. JUST SOUTH OF
SAN LUIS BET 1IVE1.
OFFSHOBE - SMOOTH SAVD »LXIH.
ONSHOSt - WIDE SAND BEACH BACKED BX LOW-LXINO
DEVELOFHEHT AND OCEAHSIDE HAXBOX. JUST SOUTH
OF OCEAHSIDI HAB.BOB, EHTKANCE JETTY.
OFFSHOUX - SMOOTH SAHD FLAIN.
Data Source: Tekmarine Inc., surveyed for U.S. Army Corps of Engineers
October, 1987
** a 2-mile long quarry revetment along the entire South Oceanside shoreline, as far as the boundary
m with the City of Carlsbad. It is not difficult to reason that the south fillet owes its existence to the
m littoral drift arriving from the south, i.e., along the beaches to its south, hence that it exists at the
m expense of this 2-mile stretch of South Oceanside and perhaps further south in Carlsbad.
Figure B-4 depicts schematically the perceived behavior of littoral sediment along a 5-mile
— shoreline south of the Oceanside Harbor as far south as Beach Avenue, Carlsbad. As already stated,
-*jjt the sandy beach of the south fillet terminates north of Wisconsin Avenue. The 2-mile revetment
m section further south functions as the feeder area to nourish the south fillet to its north. Part of the
m sediment converging on the south fillet ends up in the harbor entrance and part of it in the deep
water offshore after being deflected seaward by the south breakwater.
On the other hand, the feeder area is considered to extend beyond the revetment section of
•South Oceanside into Carlsbad, but it is difficult to speculate the length of this extension beyond the
*»• city boundary because of the overlapping influence of the offshore natural kelp bed off Beech
m Avenue. Here, the reduced wave action in the lee of the kelp bed has given rise to a bulged
shoreline, and it is reasoned that retardation of longshore currents was responsible for local sediment
accretion and hence the formation of a bulged shoreline. It appears that while some sand from this
beach has been lost to the Oceanside Harbor south fillet, the accretion associated with the natural
"™ .kelp bed has been more than enough to make up for this loss.
p. Seasonal Reversal of Longshore Currents
mm
Figure B-5 summarizes two-year observations of longshore currents performed by the park
"" rangers at two locations within the South Carlsbad State Beach on behalf of the Corps of Engineers
*" LEO (Littoral Environment Observation) program. The data was sorted and processed by the U.S.
.. Army Coastal Engineering Research Center in 1979 for Tekmarine, Inc. It is obvious that longshore
^ currents reverse themselves from season to season. The summer months, June through September,
are the period of northerly currents, whereas the winter months, December through April, are the
period of southerly currents. The months of May, October and November represent the time of
""* transition between the two contrasting seasons.
MM Changes in Beach Profile
Figure B-6 shows 1) typical seasonal profiles and 2) maximum depth (or closure depth) of
profile changes. In this region, sediment moves onshore during the summer season when the wave
w climate is dominated by the long-period swell from the Southern Hemisphere, and it moves offshore
Hi in the winter months under the dominant influence of the local storm-generated waves. In Figure
B-6, the fall profiles represent the aftermath of the summer regime and the spring profiles that of
™RI^ the winter regime.
In the Oceanside littoral cell, the closure depth usually occurs at 20 to 25 ft below MLLW,
m VI
m
m
as shown in Figure B-6. It is important to realize that the closure depth relates only to normal wave
activities. Under extreme waves, significant profile changes can take place at depths much greater
than the closure depth. A case in point is the profile changes associated with the historical January
18, 1988 storm. Waves during this storm reached a peak height of about 30 ft in the deep water, and
a peak height of about 15 ft in the nearshore zone off Oceanside. As shown in Figure B-7, profile
changes associated with this extreme event extended far beyond the closure depth. Conspicuously,
off Tamarack, profile changes in the nearshore region down to -15 ft (MLLW) were very small,
simply because there was not much sand to lose here anyway.
IH
m
m
m
Vll
KELP
FH.UT
OCEANSIDE HARBOR
BUENA VISTA LAGOON
Figure B-4 Schematic illustration of beach sediment behavior south of Oceanside Harbor
via
h
SEASONAL LONGSHORE CURRENT REVERSAL
AT CARLSBAD, CALIFORNIA
o o
o
JAN FEE MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
NORTH CARLSBAD o SOUTH CARLSBAD
DATA PROCESSED BY TEKMARINE, INC.
DATA SOURCE: US ARMY CERC LITTORAL ENVIRONMENTAL
OBSERVATION (LEO) PROGRAM- 1969 & 1970
Figure B-5 Seasonal longshore currents along the Carlsbad shoreline
30T
I
o»»
TP
20H
u
CJ -30-1
-SO-l
FAIL
LEGEND
*• HONUHENT
OCTOBER . IMSAPRIL i ISM
• MAX DEPTH OF
PROFILE CHANCE (FT)
2000 4000
HORIZONTAL SCALE (FT)
6000 8000
Figure B-6 Typical profile changes and closure depths for Oceanside Littoral Cell
»IL li. 1*11
FORSTER AVE, OS
NEARSHORE PROFILE COMPARISON FOR RANGE LINE OS-0930
: EROSION ACCRETION
TAMARACK, CB
••—• JAXVAKV J7, !*••
•—• *»»IL n. i»tt
NEARSHORE PROFILE COMPARISON FOR RANGE LINE CB-0830
Figure B-7 Profile changes during the January 18, 1988 storm
XI
Appendix C
Beach and Nearshore Profiles to April, 1993
(Wading Profiles)
I t 1 II I i i I 1 I I I i i 1 f 1 I 1 I 1 I I • 1 • 1 I I 1 1 I 1 I 1
35 I i i i i I 35
30 —
25 —
20 —
I
-U
10 —co
to
> 503i— 1
LU
0 —
-5 —
-10 —
APR93
APR92
APR91
APR90
APR89
APRSB
MLLW
- 30
— 25
— 20
15
— 10
— 5
— 0
— -5
— -10
-15 -15II I I I
100 200 300 400 500 600 700 800
RANGE (feet seaward of range line monument)
900 1000
LINE 960
ii ii li ii i i ii i i 11 ii 11 if 11 I i • i ii ii ii
30
25 —
20 —
15 —
_1
Z
I 10 —
co
•rl
•4J
CD
0}i—I
LU
5 —
-5 —i
-10 —
-15
30
— 25APR93
APR92
APR91
APR90
APRB9
APR88
i — i — i — — i — r~i — r~ — i — i — i — i — — i — TH — i — — i — i — i — i — — i — i — i i — i — i — i — — i — i — i — i — — rn — r
RANGE (feet seaward of range line monument)
LINE 930
• i ii • i • i 11 • i • i i i i i ii i i r i • § Bi I « • * • •
30 I I I I I I I I I I I I I I I I I
25
30
— 25APR93
APR92
APR91
APR90
APR89
APR88
-15
100 200 300 400 500 600 700 800
RANGE (feet seaward of range line monument)900 1000
LINE 880
I 1 J 11 II II I k , , , , , , , I I I 1 I I I I • I I 1 I I 1 I I I
50 50
APR93
APR92
APR91
APR90
APR89
APR88
— -10
-15 -15
100 200 300 400 500 600 700
RANGE (feet seaward of range line monument)
800 1000
LINE 850
litiijlltiiiiifiiflilitllillllliliiiii
30
APR93
APR92
APR91
APR90
APR89
APR88
30
— 25
— 20
— 15
— 10
L— 0
-5
h- -10
-15 -15
100 200 300 400 500 600 700 BOORANGE (feet seaward of range line monument)900 1000
LINE 840
I ] I 1 I I I I 1 1 I if i 1 1 f i I i I 1 I I I 1 I I • I • 1 t 1 1 i i i
30
25
20 —
15 —I
10 —
30
co
""*4J
CO>
0)
5 —
o —
-5 —
-10 —
APR93
APR92
APR91
APR90
APR89
APR88
-15
MLLW
— 25
— 20
i— 15
— 10
— 5
— 0
-5
I— -10
-15I T 1 | I \ I
100
i i I T r i i \ \ i i r
200 300 400 500 600 7DO BOORANGE (feet seaward of range line monument)900 1000
LINE 830
II II 1 i II 11 if I J fi II f i II II I 1 I 1 II II II II II
30 30
25 —
20 —
APR93
APR92
APR91
APR90
APR89
APR88
15 —
•X.
_J
10 —
co
•rH
4J
CO
•>
CD
i—1
LU
5 —
0 —
-5 —
-10 —
-15
MLLW
— 25
— 20
— 15
— 10
r— 0
— -5
— -10
i i i i i i i i i i i i i i i i -15
100 200 300 400 500 600 700 BOORANGE (feet seaward of range line monument)900 1000
LINE 820
1 I 1 1 I 1 1 I 1 I i I ! fill III Iflll-llllllllllll
65 65
APR93
APR92
APR91
APR90
APR89
APR88
100 200 300 400 500 600 700
RANBE (feet seaward of range line monument)
LINE 780
BOO 900 1000
II II 11 II 1 1 11 I I t i II II II II 1111 I i II II I i I I
75
APR93
APR92
APR91
APR90
APR89
APR88
100 200 300 400 500 600 700
RANGE (feet seaward of range line monument)
LINE 740
800 900 1000
, , , | j I I I I 1 I i 1
30
— 25APR93
APR92
APR91
APR90
APR89
APR88
— -10
-15 -15
100 200 300 400 500 600 700 800RANGE (feet seaward of range line monument)900 1000
LINE 760
I 1 I i 1 i I i I i ! i I ! f 1 I 1 • 1 I 1 • I I 1 I 1 I I I I
30 30
— 25
— 20
APR93
APR92
APR91
APR90
APR89
APR88
— -10
-15 -15
100 200 300 400 500 600 700 800RANGE (feet seaward of range line monument)900 1000
LINE 720
Appendix D
Entire Profiles to April, 1993
(Wading + Boat Profiles)
1 I • I • i I I 1 I I I i I I I i I i i i I i i 1 • i I 1 • i i i
30
I
4J
co
-rt
4J
(0>
0)
f-l
ID
APR93
APR92
APR91
APR90
APR89
APR88
1000 1500 2000 2500 3000 3500 4000 4500
RANGE (feet seaward of range line monument)
5000 5500
-50
6000
LINE 930
II II t J II II II I ! I I II f I II II fill 11 11 11 I*
30
25
20
15
10
5
5
I -54JM-
-10co
-|H
-P -15
CD
I -20
LU
-25
-30
-35
-40
-45
-50
MLLW
30
25
20
15
10
5
0
--20
;-25
:-30
—35
:-40
--45
-50
500 1000 1500 2000
RANGE (feet seaward of range line monument)
2500 3000
LINE 830
1 j • I 1 i 1 I I i i f 1 f ! f 1 I i t 1 ft i i i • 1 * *
CO
ILU
30
25
20
15
10
5
°
-5
-10
-15
-20
-25
-30
-35
-40-
-45 :
-50
500 1000 1500 2000 •
RANGE (feet seaward of range line monument)
LINE 820
2500
MLLW
30
25
20
15
10
5
°
--5
:-20
•-25
--30
;-35
--40
:-45
-50
3000
II i 1 II I i II II If II fi II II II III! i i
30 30
APR93
APR92
APR91
APR90
APR89
APR88
-50 -50
500 1000 1500 2000
RANGE (feet seaward of range line monument)
2500 3000
LINE 760
I I I 1 I I I I I I I i 1 t 1 i I 1 f I I 1 I I I 1 1 i I I 1 I 1 I
30
APR93
APR92
APR91
APR90
APR89
APR88
500 1000 1500 2000.
RANGE (feet seaward of range line monument)
2500
-50
3000
LINE 720
Appendix £
Time History of MLLW Shoreline Position to April, 1993
I I I i I i l i I i I I t I I i I i I 1 I 1 • 1 • i l 1 • 1 I 1 I i I i I 1
Carlsbad MLLWShoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
720
740
760
780
820
830
840
850
880
930
SEP '87
416
360
280
422
326
165
235
390
325
358
APR '88 OCT'88
183
162
117
210
220
208
245
265
125
. 298
^':''-f^S^ •"•'' ^^1^^^
253
182
182
307
260
177
200
350
293
308
APR '89
216
175
235
270
206
210
236
300
230
295
MONTH AND
OCT'89
220
270
240
365
220
330
163
323
284
322
YEAR
APR '90
173
232
281
401
156
235
240
339
265
304
OCT90
307
380
245
321
240
160
192 "'
382
336
415
llKi^
APR -91
192
231
126
216
278
204
159
353
250
307
OC7"9f
328
385
321
407
332
212
223
406
349
355
APR "92
270
240
209
247
343
253
111
366
227
290
OCT'92
356
361
311
332
328
172
312
354
300
391
APR -93
181
227
169
238
342
248
153
304
186
292
l|i|WKIft^iSl^^/^'1*$^«-' '"'s,^3§S~/~.; i ' 3BG
425
Shoreline Position (ft.): Line 960/Oceanside Blvd.
UNIT: FEET
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR"90 OCT90 APRW OCT"91 APR"92
MONTH AND YEAR
OCT'92 APR "93
II 11 11 II 11 I! I
tj
J I if 1 f ! I I I 1 1 1 1 1 1 1 1 I 1 I 1 I I !
Carlsbad MLL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
SEP '87
416
360
280
422
326
165
235
390
325
iillllllillfi
320
APR '88
183
162
117
210
220
208
245
265
125
iii'Silllliii
345
OCT'88
253
182
182
307
260
177
200
350
293
400
APR '89
216
175
235
270
206
210
236
300
230
Illllll
325
MONTH AND
OCT'89
220
270
240
365
220
330
163
323
284
iillllaliiiiii1!!
370
YEAR
APR "90
173
232
281
401
156
235
240
339
265
IlliSflill
335
OC790
307
380
245
321
240
160
192 »
382
336
111 11 111
321
APR -91
192
231
126
216
278
204
159
353
250
11 111 1
346
OCT-91
328
385
321
407
332
212
223
406
349
355
313
APR "92
270
240
209
247
343
253
277
366
227
340
OCT92
356
361
311
332
328
172
312
354
300
392
APR "93
181
227
169
238
342
248
153
304
186
350
UNIT: FEET
Shoreline Position (ft.): Line 930/Morse Avenue
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR'90 OCT90
MONTH AND YEAR
APR "91 OCT91 APR '92 OCT-92 APR "93
ii ii ii ii ii ii ii ii 11 ii ii-ii 11 11 ii ii i i
Carlsbad MLL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
720
740
760
780
820
830
840
850
SEP '87
416
360
280
422
326
165
235
390
APR '88
183
162
117
210
220
208
245
265
OCT'88
253
182
182
307
260
177
200
350
MONTH AND
APR '89 OCT'89
216
175
235
270
206
210
236
300
220
270
240
365
220
330
163
323
YEAR
APR -90
173
232
281
401
156
235
240
339
OCT90
307
380
245
321
240
160
192 '
382
APR -91
192
231
126
216
278
204
159
353
OCT91
328
385
321
407
332
212
223
406
APR "92
270
240
209
247
343
253
277
366
OCT'92
356
361
311
332
328
172
312
354
APR -93
181
227
169
238
342
248
153
304
'ii^^
358
320
• 298
345
308
400
295
325
322
370
304
335
415
321
307
346
355
313
290
340
391
392
292
350
930
560
UNIT: FEET
Shoreline Position (ft.): Line 880/Buena Vista Lagoon
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR W OCT90
MONTH AND YEAR
APR "91 OCTW APR "92 OCT'92 APR "93
I I I I I I I I I I I i I f i I i I 1 I I 1 1 1 I I 1 I 1 I I I 1 I 1 1 I
Carlsbad MLLW Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
SEP '87
416
360
280
422
326
165
235
APR '88
183
162
117
210
220
208
245
OCT'88
253
182
182
307
260
177
200
IliillllS®^
325
358
320
125
• 298
345
293
308
400
APR '89
216
175
235
270
206
210
236
230
295
325
MONTH AND
OCT'89
220
270
240
365
220
330
163
284
322
370
YEAR
APR "90
173
232
281
401
156
235
240
iiiiniiiibiii
265
304
335
OCT-90
307
380
245
321
240
160
192 '
APR "91
192
231
126
216
278
204
159
OCTW
328
385
321
407
332
212
223
APR "92
270
240
209
247
343
253
277
OCT-92
356
361
311
332
328
172
312
APR "93
181
227
169
238
342
248
153liiiiffl
336
415
321
250
307
346
349
355
313
227
290
340
300
391
392
186
292
350
STATION
720
740
760
780
820
830
840
880
930
960
UNIT: FEET
425
Shoreline Position (ft.): Line 850/Pine Avenue
SEP '87 APR'88 OCT'88 APR'89 OCT'89 APR '90 OCTW
MONTH AND YEAR
APR "91 OCT"91 APR "92 OCT'92 APR'93
ii ii ii it i i i i i i i i i I i r i ii till ii 11 11 11 i i
Carlsbad MLLW Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
SEP '87
416
360
280
422
326
165
APR '88
183
162
117
210
220
208
OCT'88
253
182
182
307
260
177
APR '89
216
175
235
270
206
210
MONTH AND
OCT'89
220
270
240
365
220
330
YEAR
APR '90
173
232
281
401
156
235
OCT90
307
380
245
321
240
160
APR "91
192
231
126
216
278
204
OCT"9J
328
385
321
407
332
212
APR 92
270
240
209
247
343
253
OC7"92
356
361
311
332
328
172
APR "93
181
227
169
238
342
248
; W":/f .ij^g^i'i,.",.,, 1'.'$% i.y? f i|i|||!piii»* 1i'$Pii|!W^^ • •'< : ^3t2'^ ft: "' IfiilS
390
325
358
320
265
125
. 298
345
350
293
308
400
300
230
295
325
323
284
322
370
339
265
304
335
382
336
415
321
353
250
307
346
406
349
355
313
366
227
290
340
354
300
391
392
304
186
292
350
STATION
720
740
760
780
820
830
VWSi
650
880
930
960
UNIT: FEET
Shoreline Position (ft.): Line 840/Acacia Avenue
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR'90 OCTW
MONTH AND YEAR
APR "91 OCT91 APR '92 OCT"92 APR'93
• I II II 11 I! 11 il f! li 11 11 II 111! II II II II II
Carlsbad MLL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
720
740
760
780
820
•,;;£» i
540
050
880
930
960
SEP '87
416
360
280
422
326
APR '88
183
162
117
210
220
OCT'88
253
182
182
307
260
APR '89
216
175
235
270
206
MONTH AND
OCT'89
220
270
240
365
220
YEAR
APR "90
173
232
281
401
156
OCT-90
307
380
245
321
240
APR "91
192
231
126
216
278
OCTW
328
385
321
407
332
APR '92
270
240
209
247
343
;,«,;%/;'' ipi^
235
390
325
358
320
245
265
125
. 298
345
200
350
293
308
400
236
300
230
295
325
163
323
284
322
370
240
339
265
304
335
192
382
336
415
321
159
353
250
307
346
223
406
349
355
313
277
366
227
290
340
OCT-92
356
361
311
332
328
APR "93
181
227
169
238
342
NyW^™^ i-SlS
312
354
300
391
392
153
304
186
292
350
UNIT: FEET
350
Shoreline Position (ft.): Line 830 / Tamarack Avenue
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR"90 OCT"90
MONTH AND YEAR
APR "91 OCTW APR "92 OCT-92 OCT93
t I •: I I • I I 1 I I I f ! I I f ] I 1 I I I 1 • 1 I 1 I 1 I 1 I i I 1
Carlsbad MLL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
720
740
760
780
830
840
850
880
930
960
SEP '87
416
360
280
422
liliiiiiliiJilsSiili.'!!,!
165
235
390
325
358
320
APR '88 (
183
162
117
210
fliiiflilMifcifll
208
245
265
125
. 298
345
JCT'88
253
182
182
307
177
200
350
293
308
400
APR '89
216
175
235
270
ii!ii|28ii!
210
236
300
230
295
325
MONTH AND
OCT'89
220
270
240
365
iiiiiWiiiii!
330
163
323
284
322
370
YEAR
APR "90
173
232
281
401
i''!iiliiliiil
235
240
339
265
304
335
OCT-90
307
380
245
321iiiiiiiiii
160
192 '
382
336
415
321
APR "91
192
231
126
216
204
159
353
250
307
346
OCT-91
328
385
321
407
IlilllljiN
212
223
406
349
355
313
APR '92
270
240
209
247
:ia«giiii'<liPil
253
277
366
227
290
340
OCT-92
356
361
311
332
i'lli "IIIPP
172
312
354
300
391
392
APR "93
181
227
169
238
^•folB
248
153
304
186
292
350
UNIT: FEET
350
325
300
275
250
225
200
175
150
SEP '87
Shoreline Position (ft.): Line 820/Agua Hedlonds South
/
APR'88 OCT'88 APR'89 OCT'89 APR'90 OCT90
MONTH AND YEAR
APR "91 OC7"9J APR ^2 OCT92 APR "93
• 1 II II II il tl II II 11 II II II 1111 II II 11 II II
Carlsbad MLLWShoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
SEP '87
416
360
280
APR '88
183
162
117
OCT'88
253
182
182
APR '89
216
175
235
MONTH AND
OCT'89
220
270
240
YEAR
APR '90
173
232
281
OCT'90
307
380
245
APR "91
192
231
126
^; ^fj^t^^pv^^ $i!ifl^
326
165
235
390
325
358
320
220
208
245
265
125
298
345
260
177
200
350
293
308
400
206
210
236
300
230
295
325
220
330
163
323
284
322
370
156 .
235
240
339
265
304
335
240
160
192
382
336
415
321
278
204
159
353
250
307
346
OCT91
328
385
321
APR '92
270
240
209
OCT92
356
361
311
APR -93
181
227
169
iilllllliji.i^M.i^^c, :.''f$&%.v. • 1.238
332
212
223
406
349
355
313
343
253
277
366
227
290
340
328
172
312
354
300
391
392
342
248
153
304
186
292
350
STATION
720
740
760
820
830
840
850
880
930
960
UNIT: FEET
Shoreline Position (ft.): Line 780 / Palomar AP Road
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR"90 OCT'90
MONTH AND YEAR
APR "91 OCT-91 APR "92 OCT-92 APR "93
ft 1 ft 1 I ft I ft I II II 11 I I I I II II 1111 II II II II II
Carlsbad MIL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
SEP '87 APR '88 OCT'88
416
360
'^.mm^
422
326
165
235
390
325
358
320
183 253
162 182
illil^^lR^IISlSi^'l1
210 307
220 260
208 177
245 200
265 350
125 293
298 308
345 400
MONTH AND YEAR
APR '89 OCT'89 APR "90 OCT'90 APR "91 OCT"91 APR '92 OCT92 APR -93
216 220 173 307 192 328 270 356 181
175 270 232 380 231 385 240 361
i'SfciS^Wl'ii'Sii^i^ftiWi
270 365 401
llllH^
227
'f,i *t lin ,' Vj ,&>$.:, ±yW" "'.','>'W:
321 216 407 247 332 238
206 220 156 240 278 332 343 328 342
210 330 235 160 204 212 253 172 248
236 163 240 192 * 159 223 277 312 153
300 323 339 382 353 406 366 354 304
230 284 265 336 250 349 227 300 186
295 322 304 415 307 355 290 391 292
325 370 335 321 346 313 340 392 350
STATION
720
740
780
820
830
840
850
880
930
960
UNIT: FEET
Shoreline Position (ft.): Line 760/Encinas Creek
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR'90 OCT'90
MONTH AND YEAR
APR-91 APR "92 OCT-92 APRV3
I I I I I • 1 II ft 1 II • I II II II II lit! II II II II II
Carlsbad MLLWShoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
720
760
750
820
830
840
850
880
930
960
SEP '87
416!iii!si3W!:
280
422
326
165
235
390
325
358
320
APR '88 OCT'89 APR '89
183 253 216ili
117 182 235
210 307 270
220 260 206
208 177 210
245 200 236
265 350 300
125 293 230
. 298 308 295
345 400 325
MONTH AND
OCT'89
220i!!!!£|$!!!
240
365
220
330
163
323
284
322
370
YEAR
APR "90
173.yillllli
281
401
156
235
240
339
265
304
335
OCT90
307
1111! 11 111
245
321
240
160
192 v
382
336
415
321
APR "91
192
126
216
278
204
159
353
250
307
346
OC7"9J
328
321
407
332
212
223
406
349
355
313
APR "92
270iiiiiiii!1!
209
247
343
253
277
366
227
290
340
OCT-92
356
311
332
328
172
312
354
300
391
392
APR -93
181
.r'i'll^f
169
238
342
248
153
304
186
292
350
UNIT: FEET
Shoreline Position (ft.): Line 740 /Poinsettia Lane
SEP'87 APR'88 OCT'88 APR'89 OCT'89 APR'90 OCT9Q
MONTH AND YEAR
APR "91 OCTS/APR "92 007-92 APRW
I I I I I I I I I 1 I I I 1 I I I 1 I 1 I I I 1 I i I 1 I I 1 I I I I I I 1
Carlsbad MLL W Shoreline Position
Data 3: Mean Lower Low Water (MLLW) Shoreline Position
STATION
740
760
780
820
830
840
850
880
930
960
SEP '87 APR '88 OCT'88 APR '89
liXK^^^K''^
360 162
280 117
422 210
326 220
165 208
235 245
390 265
325 125
358 , 298
320 345
1^^1111^1^!182 175
182 235
307 270
260 206
177 210
200 236
350 300
293 230
308 295
400 325
MONTH AND YEAR
OCT'89 APR "90 OCTW APR W OCT"91
270 232 380 231 385
240 281 245 126 321
365 401 321 216 407
220 156 240 278 332
330 235 160 204 212
163 240 192 ' 159 223
323 339 382 353 406
284 265 336 250 349
322 304 415 307 355
370 335 321 346 313
APR '92 OCT-92 APR "93
l^^Q^'^^^^^-^^\240 361 227
209 311 169
247 332 238
343 328 342
253 172 248
277 312 153
366 354 304
227 300 186
290 391 292
340 392 350
Shoreline Position (ft.): Line 720 / Batiqultos Lagoon
UNIT: FEET
APR'88 OCT'88 APR'89 OCT'89 APR'90 OCT90
MONTH AND YEAR
APRW OCTW APR'92 OCT'92 APR '93
Appendix F
Beach Profile Survey Method
m
m
m
m
m
mm
Figure F-l provides a schematic illustration of the procedures used for the sand survey and
beach profile program. The procedures employed in the April 1992 survey are consistent with those
used in the previous surveys since September 1987. These procedures have been designed to satisfy
the accuracy and quality control criteria stipulated by the U.S. Army Corps of Engineers in support
of the survey program for the Coast of California Storm and Tidal Waves Study.
Survey Type
Wading
Boat
Survey Accuracy Criterig.
Vertical Accuracy
± 0.1 ft
± 0.5ft
Horizonal Accuracy
± 1.0ft
± 10.0 ft
m
a
Ha
m
m
WAGING SURVEY
SVYIMMO WITH EXIEHOAeii HOP
RANGE TARGET SHORE SURVEYOR WITH
-"ELECTRONIC DISTANCE METER (60M|
FAJHOMUlll SURVEY
INflAIAUt IOATWITHFATHOMtnUAHOCOM «EH£CTO«
RANCE LINE MONUMENT
RANGE TARGET
Figure F-l Survey Methods