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HomeMy WebLinkAbout; ; Beach Sand Level Measurements 1981-1983; 1983-04-01BEACH SAND LEVEL MEASUREMENTS OCEANSIDE AND CARLSBAD, CALIFORNIA December 1981 to February 1983 Data Report by B. Walton Waldorf, Reinhard E. Flick and D. Murray Hicks SIO Reference No. 83-6 April 1983 Shore Processes Laboratory Center for Coastal Studies, A-009 Scripps Institution of Oceanography La Jolla, California 92093 TABLE OF CONTENTS BACKGROUND 1 PROCEDURE 1 RESULTS '2 OCEANSIDE ONSHORE WADING BEACH PROFILES 8-21 CARLSBAD ONSHORE WADING BEACH PROFILES . . 22-32 OCEANSIDE OFFSHORE FATHOMETER BEACH PROFILES 33-35 CARLSBAD OFFSHORE FATHOMETER BEACH PROFILES 36-37 BACKGROUND This report presents the beach profile data gathered in the monitoring program at Oceanside and Carlsbad, California. Since Oceanside and Carlsbad are so closely coupled within the Oceanside Littoral Cell, data collected from their separate beach monitoring projects are presented together. Systematic beach profile measurements identify seasonal fluctuations as well as trends in erosion or accretion, and may provide useful background information for future shorefront projects. Also, a secondary objective is to monitor the longshore transport of the beach fill completed at the Ocean- side City Beach in approximately May 1982. A quantitative evaluation of the dispersion rate of the beach fill and its effectiveness may be possible from the combined measurements from Oceanside and Carlsbad. PROCEDURE Nine range!ines in Oceanside, and seven in Carlsbad, have been profiled at monthly intervals to maximum wading depths (typically -1 m MSL) at low tide. Figures 1 and 2 show the location of range!ines. Figure 3 schematically illustrates the surveying procedure. Standard surveying practices using an automatic surveyor's level and leveling rod for elevation measurements, and a stainless steel line to determine distance were used. To provide vertical and horizontal reference points, permanent bench marks have been installed in a stable portion of the beach backshore. Each benchmark has a brass nameplate epoxyed into concrete with a unique number identifying the monument. Offshore fathometer profiles were conducted quarterly during times of high spring tide and an effort made to overlap with the subaerial survey. The offshore profiles were calibrated with diver measured brass reference rods to help remove wave induced uncertainty. The offshore fathometer profiles have been measured at Oceanside Ranges 1,4, and 7; and Carlsbad Ranges 1 and 6, extending the wading pro- files to approximately -10 m depth (see pages 33 to 37). For each of these profiles sand volumes have been calculated by integrating the area between / a given profile and an arbitrary horizontal level below any actual profile 2changes. This procedure gives an area (m ) or equivalently, a volume per 2unit length of beach (m /m of beach length). These volumes have been repre- sented as bar graphs and included on pages 33 to 37. The stippled portion of each bar represents the volume of sand on the onshore profile from 0 to 250 m offshore, while the unstippled bar represents the offshore portion of the profile from 250 to 500 m. RESULTS To nourish the depleted beach in south Oceanside, the city imported 3706,000 m of sand from the San Luis Rey River bed and distributed it along the portion of the beach between the Oceanside Pier and the Buena Vista Lagoon. The beach fill project has been successful in the sense that the early storms of this past winter dissipated much of their energy on the beach fill, redi- stributing the sand offshore to form sand bars. In subsequent storms, this pronounced offshore bar was effective in causing the waves to shoal and break farther to sea than would have been the case without the sand. The bar forma- tions exist about 250 to 500 m offshore in depths of about -5 to -8 m, as shown by the profiles on pages 33 to 37. This suggests the milder waves of spring and summer will be successful in returning most of the sand stored in the bar to the subaerial beach. Additional profile measurements will show how much of the fill currently in the offshore deposit returns to the beach face. Tracing the three dimensional movements of the beach fill will also yield the portion that moves southward onto Carlsbad's beach, although this is quantitatively less certain than documentation of on-offshore changes. Preliminary review of the data suggests the following sequence of fill sand dispersion. (See figures on pages 33 to 37). During the mild wave con- ditions of the 1982 spring and summer period, fill sand was dispersed along- shore, mainly to the north. This is evident by net accretion between May and September 1982 on Ranges 1 and 4, and by net erosion on Range 7 in Ocean- side. During the winter, storm waves caused generally severe erosion of the beach face and inshore zone along the entire Oceanside-Carlsbad reach. It is clear from the changes in the September to December 1982 fathometer profiles (Oceanside Ranges 1, 4, and 7; Carlsbad Range 1) that the eroded beach face has been deposited as an offshore bar. There is also evidence of a strong net southerly longshore movement associated with this on-offshore sand migra- tion: from September 1982 to February 1983, Oceanside Ranges 1 and 4 suffered net erosion, while those to the south, Oceanside Range 7 and Carlsbad Range 1, accreted overall. The accretion of Carlsbad Range 1, despite the severe wave conditions of this past winter, can only be accounted for by southerly migration of Oceanside beach sand. The more southerly Carlsbad rangelines show a comparatively smaller winter depletion of the beach face, simply because there was little sand there to be eroded. Most profiles are presently reduced to a discontinuous layer of cobbles over the wavecut bedrock platform. This also explains the lack of a winter bar off Carlsbad Range 6. The foregoing demonstrates that the fill-sand placed on the south Oceanside beaches last spring has benefited that city in two ways: by pro- viding an aesthetic beach during the summer and by forming a protective off- shore bar during the winter. The continued usefulness of the fill and the requirement for future fill now depends on how much sand returns to the beach face this summer, and where it returns. Only continued monitoring can answer these questions. ACKNOWLEDGEMENTS Ongoing financial support for the survey programs from the citizens of the City of Oceanside and the City of Carlsbad is gratefully acknwledged. 33°I2'30" USGS 7.5 QUAD. 1968 0 1/2 I km ALL CONTOURS IN FEET 117° 22'30" Figure 1. Map of Oceanside, California showing location of beach profile monitoring program rangelines. 10 - 33°07'30" USGS 7.5 QUAD. 1968 0 1/2 I Km ALL CONTOURS IN FEET II7°22'30"20' Figure 2. Map of Carlsbad, California showing location of beach profile monitoring program rangelines. LAND SURVEY A OFFSHORE SURVEY A HIGH £?•'" \ BENCH MARK A. PROFILE REFERENCE RODS RANGE 0 SURVEY BOAT B. PLAN Figure 3. Schematic illustration of onshore and offshore survey methods. pg 8 Oceanside 2M 3 82 13:51, RRNGE 1 21 >4 82 12:05 , RRNGE 1 20 5 82 11:22, RflNGE 1 25 6 82 9 :15, RRNGE 1 DISTANCE OFFSHORE (M) -4 180 160 140 120 100 80 60 40 20 0 Oceanside 28 7 82 1-0:11, RflNGE 1 20 8 82 16:39, RflNGE 1 17 9 82 12:00 .RflNGE 1 13 10 82 11:30, RRNGE 1 T 10 DISTRNCE OFFSHORE (M) CD 130 160 140 120 100 60 40 20 0 pg 9 Oceanside 11 11 82 11:25, RRNGE .1 16 12 82 8 :48, RflNGE 1 26 1 83 13:45, RRNGE 1 24 2 83 12:35, RflNGE 1 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 Oceanside 24 3 82 14:30, RRNGE 2 21 4 82 13:05 , RflNGE 2 21 5 82 15:36, RflNGE 2 25 6 82 8 :46, RflNGE 2 T 10 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 Oceanside 28 7 82 9 :48, RflNGE 2 20 8 82 16:28, RflNGE 2 16 9 82 13:08 , RflNGE 2 13 10 82 12:03 .RflNGE 2 pg 10 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 80 60 20 0 Oceanside 11 11 82 12:05 .RflNGE 2 14 12 82 14:45, RflNGE 2 26 1 83 14:21, RflNGE 2 24 2 83 13:15, RflNGE 2 T 10 - 8 -•6 DISTflNCE OFFSHORE (M) - 4 •• 2 •- 0 CL > UJ_J UJ •• -2 -4 180 160 140 120 100 60 40 20 0 Oceanside 2^ 3 82 1M:M9, RRNGE 3 21 >4 82 13:50, RflNGE 3 21 5 82 15:15, RRNGE 3 25 6 82 8 :22, RflNGE 3 DISTflNCE OFFSHORE (M) pg 11 T 10 •• 8 -6 o -.0 LU ••-2 -4 180 160 140 120 100 60 20 0 Oceanside 28 7 82 9 :24, RflNGE 3 20 8 82 15:57, RflNGE 3 16 9 82 13:29, RflNGE 3 13 10 82 12:21, RflNGE 3 DISTflNCE OFFSHORE (M) CL -4 180 160 140 120 100 60 40 20 0 Oceanside 11 11 82 12:30, RRNGE 3 14 12 82 15:00 .RflNGE 3 26 1 83 1M:37, RflNGE 3 2^ 2 83 13:35, RflNGE 3 DISTflNCE OFFSHORE (M) pg 12 T 10 •8 •6 .. 0 UJ -•-2 180 160 140 120 100 60 40 20 0 Oceanside 2M 3 82 15:34, RflNGE 4 21 4 82 m-M, RflNGE 4 20 5 82 12:03 .RflNGE V 25 6 82 8 :21, RflNGE 4 DISTRNCE OFFSHORE (M) \—.—I—.—I—. T 10 - 8 .. 0 cr> UJ_j UJ • -2 180 160 140 120 100 60 40 — 1 20 0 Oceanside 28 7 82 9 :00 ,RRNGE 4 20 8 82 15:37, RRNGE 4 17 9 82 12:30, RRNGE 4 13 10 82 12:44, RflNGE 4 P9 13 DISTflNCE OFFSHORE (M) • -2 -4 180 160 140 120 100 60 40 20 0 Oceanside 11 11 82 12:48, RflNGE 4 16 12 82 9 :15, RRNGE 4 26 1 83 14:52, RflNGE 4 24- 2 83 14:00 .RflNGE 4 10 8 DISTflNCE OFFSHORE (M) cr • -2 180 160 140 120 100 60 40 20 0 Oceanside 24 3 82 15:22, RflNGE 5 21 M 82 15:20, RRNGE 5 21 5 82 1M:53, RflNGE 5 25 6 82 7 :M3, RRNGE 5 P9 14 _ 10 DISTflNCE OFFSHORE (M) CD CE • -2 -4 180 160 140 120 100 80 60 40 20 0 Oceanside 28 7 82 8 :47, RflNGE 5 20 8 82 15:19, RflNGE 5 16 9 82 13:51, RflNGE 5 13 10 82 13:03 .RflNGE 5 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 80 60 40 20 0 Oceanside 11 11 82 13:07 .RflNGE 5 14 12 82 16:51, RflNGE 5 26 1 '83 15:15, RRNGE 5 24 2 83 15:40, RflNGE 5 pg 15 DISTRNCE OFFSHORE (M) 180 160 140 120 100 60 Oceanside 24 3 82 15:52, RflNGE 6 20 M 82 15:50, RflNGE 6 21 5 82 14:25, RflNGE 6 25 6 82 7 :24, RflNGE 6 DISTRNCE OFFSHORE (M) 180 160 140 120 100 60 40 20 0 Oceanside 28 7 82 8 :30, RfiNGE 6 20 8 82 14:56, RRNGE 6 16 9 82 14:82, RflNGE 6 13 10 82 13:23, RRNGE 6 pg 16 DISTflNCE OFFSHORE (M) 180 160 140 120 100 Oceanside 11 11 82 13:30, RRNGE 6 14 12 82 16:05 .RRNGE 6 26 1 83 15:30, RflNGE 6 24 2 83 14:30, RflNGE 6 60 40 20 0 T 10 • 8 ••6 DISTflNCE OFFSHORE (M) •• 2 cr> LU _J LU .. _2 -4 180 160 140 120 100 80 60 40 20 Oceanside 2M 3 82 16:20, RflNGE 7 21 4 82 16:20, RRNGE 7 20 5 82 12:M2, RflNGE 7 25 6 82 6 :59, RflNGE 7 T 10 -•8 •• 6 DISTRNCE OFFSHORE (M)J—,—\—,—I—, -• 4 ••2 cr 0[ -2 -4 180 160 140 120 100 60 40 20 0 Oceanside 28 7 82 8 :09 .RflNGE 7 20 8 82 14:34, RflNGE 7 17 9 82 12:46, RflNGE 7 13 10 82 13:42, RflNGE 7 T 10 ••8 -6 DISTflNCE OFFSHORE (M) •• 4 -• 2 -0 .. _2 -4 180 160 140 120 100 60 40 20 0 Oceanside 11 11 82 13:5M, RRNGE 7 16 12 82 9 ^2, RflNGE 7 26 1 83 15:50, RflNGE 7 2H 2 83 14:50, RflNGE 7 pg 18 DISTRNCE OFFSHORE (M) 10 •8 •6 ••4 : ». •• 2 - 0 CDi—I I—cc> LU -2 180 160 140 120 100 60 40 20^ 0 Oceanside 21 U 82 16:M5, RflNGE 8 21 5 82 1M-.07 .RflNGE 8 25 6 82 6 :36, RflNGE 8 DISTRNCE OFFSHORE (M) 180 160 140 120 100 0 Oceanside 28 7 82 7 ;54, RRNGE 8 20 8 82 lM:m, RflNGE 8 16 9 82 1M:27, RRNGE 8 13 16 82 14:01 , RRNGE 8 P9 19 T 10 • 8 •6 DISTflNCE OFFSHORE (M) •2 • 0 o LU -2 -4 180 160 140 120 100 60 40 20 0 Oceanside 11 11 82 m:10, RflNGE 8 15 12 82 m:53, RflNGE 8 26 1 83 16:10, RflNGE 8 24 2 83 15:20, RflNGE 8 r 10 • 8 •6 DISTflNCE OFFSHORE (M) ; 2 ••0 CE -4 180 160 140 120 100 60 40 20 0 Oceanside 27 7 82 9 :55, RRNGE 9 19 8 82 16:14, RRNGE 9 16 9 82 1M:M3, RRNGE 9 1M 10 82 12:69 , RRNGE 9 P920 DISTflNCE OFFSHORE (M) CE LU -4 180 160 140 120 100 60 40 20 0 Oceanside 24 3 82 16:50, RflNGE 9 21 M 82 17:10, RRNGE 9 21 5 82 13:39, RflNGE 9 2M 6 82 8 :25, RflNGE 9 DISTflNCE OFFSHORE (M) T 10 -•8 -6 -•4 : •• 2 - 0 o CE UJ -4 180 160 140 120 100 60 40 20 0 Oceanside 12 11 82 12:00 ,RRNGE 9 15 12 82 15:05 , RRNGE 9 25 2 . 83 13:35, RflNGE 9 DISTRNCE OFFSHORE "(M) pg 21 T 10. •-8 -6 - 4 : -2 cr • -2 -4 180 160 140 120 100 60 40 20 0 CarIsbad 22 12 81 12:56, RflNGE 1 22 1 82 m:00 , RflNGE 1 23 3 82 13:37, RflNGE 1 20 it 82 11:50, RflNGE 1 20 5 82 13:33, RflNGE 1 pg 22 T DISTflNCE OFFSHORE (M) .. _2 180 160 140 120 100 60 40 20 0 CarIsbad 2LJ 6 82 8 :04 .RflNGE 1 27 7 82 9 :28, RflNGE 1 19 8 82 15:53, RflNGE 1 17 9 82 13:03 .RflNGE 1 T 10 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 Carlsbad 14 10 82 12:36, RRNGE 1 12 11 82 12:28, RPNGE 1 15 12 82 15:22, RRNGE 1 25 2 83 14:00 , RRNGE 1 pg 23 DISTflNCE OFFSHORE (M) 8 6 • 0 - -2 180 160 140 120 100 60 40 20 0 CarIsbad 22 12 81 13:27, RRNGE 2 22 1 82 14:25, RflNGE 2 23 3 82 13:58, RflNGE 2 20 4 82 12:10, RflNGE 2 21 5 82 13:01 , RflNGE 2 DISTflNCE OFFSHORE (M) T 10 ••8 -6 180 160 140 120 100 60 40 20 0 CarIsbad 2M 6 82 7 :M1. RRNGE 2 27 7 82 9 :12, RRNGE 2 19 8 82 15:26, RRNGE 2 16 9 82 15:01 , RRNGE 2 P9 24 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 0 CarIsbad 14 10 82 12:56, RflNGE 2 12 11 82 12:M5, RRNGE 2 15 12 82 15:50, RflNGE 2 25 2 83 m:25, RRNGE 2 T 10 •• 8 •• 6 •• 4 DISTflNCE OFFSHORE CM) 180 160 140 120 100 60 40 20 CarIsbad 22 12 81 13:M2, RRNGE 3 22 1 82 m:M7, RflNGE 3 23 3 82,m:21, RflNGE 3 20 M 82 12:29, RflNGE 3 21 5 82 12:"40, RflNGE 3 P9 25 DISTflNCE OFFSHORE (M) • -2 -4 180 160 140 120 100 60 40 20 0 CarIsbad 24 6 82 7 :19, RflNGE 3 27 7 82 8 :56, RflNGE 3 19 8 82 15:07 .RflNGE 3 16 9 82 15:22, RflNGE 3 T 10 DISTflNCE OFFSHORE (M) 180 160 140 120 100 60 40 20 0 CarIsbad 14 10 82 13:31, RRNGE 3 12 11 82 13:17, RRNGE 3 16 12 82 14:30, RRNGE-3 25 2 83 14:50, RRNGE 3 P9 26 DISTflNCE OFFSHORE (M) cz -2 -4 180 160 140 120 100 60 40 20 0 CarIsbad 22 12 81 14:12, RflNGE 4 22 1 82 15:08 , RflNGE 4 23 3 82 14:45, RRNGE 4 20 4 82 12:50, RflNGE 4 20 5 82 15:11, RflNGE 4 T 10 DISTflNCE OFFSHORE (M) 180 160 140 120 100 60 40 20 0 CarIsbad 24 6 82 6 :57, RRNGE 4 27 7 82 8 :39, RflNGE 4 19 8 82 14:47, RRNGE 4 17 9 82 13:31, RRNGE 4 P9 27 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 20 0 CarIsbad m 10 82 13:57, RflNGE 4 12 11 82 13:37, RRNGE M 16 12 82 14:55, RflNGE 4 25 2 83 15:15, RflNGE 4 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 CarIsbad 22 12 81 WM, RflNGE 5 22 1 82 13:27, RflNGE 5 23 3 82 15:04 .RflNGE 5 20 4 82 13:10, RflNGE 5 20 5 82 14:46, RflNGE 5 pg 28 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 CarIsbad 24 6 82 6 :38, RRNGE 5 27 7 82 8 :26, RflNGE 5 19 8 82 14:29, RflNGE 5 17 9 82 13:54, RflNGE 5 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 CarIsbad 14 10 82 14:22, RflNGE 5 12 11 82 14:00 .RflNGE 5 16 12 82 15:22, RflNGE 5 25 2 83 15:40, RflNGE 5 pg 29 DISTflNCE OFFSHORE (M) 180 160 140 120 100 60 40 20 0 CarIsbad 20 4 82 13:26, RflNGE 6 20 5 82 13:59, RflNGE 6 T 10 DISTflNCE OFFSHORE (M) cz • -2 -4 180 160 140 120 100 60 40 20 0 CarIsbad 24 6 82 6 :15, RRNGE 6 27 7 82 8 :06 .RflNGE 6 19 8 82 14:08 , RRNGE 6 17 9 82 14:10, RflNGE 6 pg 30 IQ • 8 •• 6 DISTflNCE OFFSHORE (M) o -.0 180 160 140 120 100 80 60 20 0 CarIsbad 14 10 82 14:44, RflNGE 6 12 11 82 14:18, RflNGE 6 15 12 82 16:17, RflNGE 6 25 2 83 16:10, RflNGE 6 T 10 DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 CarIsbad 20 M 82 13:56, RRNGE 7 20 5 82 1M:20, RflNGE 7 pg si 10 • 8 •6 DISTflNCE OFFSHORE (M) -2 180 160 140 120 100 60. 40 20 0 CarIsbad 24 6 82 5 :50, RRNGE 7 27 7 82 7 :H6, RflNGE 7 19 8 82 13:U7, RflNGE 7 17 9 82 14:27, RflNGE 7 10 8 • 0 CT LU DISTflNCE OFFSHORE (M) -4 180 160 140 120 100 60 40 20 0 CarIsbad 14 10 82 15:03 .RflNGE 7 12 11 82 14:35, RflNGE 7 16 12 82 15:M3, RflNGE 7 25 2 83 16:30, RflNGE 7 pg 32 DISTflNCE OFFSHORE (M) 180 160 140 120 100 60 40 20 0 Oceanside 20 5 82 7 :19, RflNGE 1 [ 17 9 82 8 :52, RflNGE 1 [ 16 12 82 8 Sq8, RflNGE 1 [ 2^ 2 83 12:35, RflNGE 1 r i.v-'iiv**l 1 100 300 500 700 SAND VOLUME (m3/m of BEACH) ......j^^&&&&£**:^^l^f*'^j^^^\^»~t~ DISTflNCE OFFSHORE (M) - 15 •-5 20 .. 0 o • -10 -15 caco 150 400 350 300 250 200 150 100 50 Oceans!de T20 20 5 82 7 ;H9, RflNGE 17 9 82 9 :19, RflNGE '.•":;;;';•:'••"••••'•.' ••••.'•'-• •;•/ •••• -'.••«••• •;'. '•'. 1I :•.•::::•:; :.-.r...;r.-.;-^.v:...-A-.-.-.>.. •?.•;-«»! 16 12 82 9 :15, RflNGE ^ [ 2 83 9 :21, RflNGE 4 r -• 15 i 100 300 SAND VOLUME (m 500 °f BEACH) -•5 -0 o DISTflNCE OFFSHORE (M) ct LU I LJ -10 450 400 350 300 250 200 -15 150 100 50 0 T3CQ co-pi Oceans!de 20 5 82 8 :15, RflNGE 7 [ 17 9 82 9 :H RflNGE 7 C 16 12 82 9 :M2, RflNGE 7 [ 2^ 2 83 9 :50, RflNGE 7 r • 15 _L 100 300 500 SAND VOLUME (mVm of BEACH) - 10 - 5 DISTRNCE OFFSHORE (M) -0 cr LUi UJ •• -10 -15 450 400 350 300 250 200 150 100 50 0 •aca cocn Car 1sbad 20 5 82 8 :i*7, RflNGE 1 17 9 82 10:12, RflNGE 1 I te^^M 16 12 82 10:18, RflNGE 1 | 25 2 83 10:26, RflNGE 1 L 1 100 300 500 700 SAND VOLUME (m3/m of BEACH) T20 - 15 - 10 - -10 h- DISTRNCE OFFSHORE (M) 450 400 350 300 250 200 150 100 50 -15 0 T3 CO COcn Carlsbad 20 5 82 9 :20, RflNGE 6 C 17 9 82 10:3M, RflNGE 6 [ 16 12 82 10:145, RflNGE 6 r t~^•".'•"••. • W:-•*» •;".~'••'• 4^.".:<!^^:^ \I I 100 300 500 SAND VOLUME (m3/m of BEACH) DISTRNCE OFFSHORE (M) T 20 • 15 ••5 - 0 GC -5^ - -10 -15 450 400 350 300 250 200 150 100 50 0 co