Loading...
HomeMy WebLinkAbout1985-07-30; City Council; Minutes( 0 MINUTES 0 Meeting of : CITY COUNCIL (Adjourned Meeting) Date of Meeting: July 30, 1985 Time of Meeting: 6:OO p.m. Place of Meeting: City Council Chambers CALL TO ORDER: The meting was called to order by Mayor Casler at 6:02 p.m. ROLL CALL was taken by the City Clerk, as follows: Present: Council Members Casler, Lewis, Kulchin, Chick and Pettine. Absent: None. APPROVAT; OF MINUTES: (one mtion) The Minutes of the Regular Meeting held July 16, 1985, were approved as presented. The Minutes of the Adjourned Regular Meeting held July 17, 1985, were approved as presented. 70) Batiquitos Lagoon Enhancement Plan Report Council Member Chick gave a status report on a recent meeting in Laguna Niguel, and the discussions regarding the possible enhancement of Batiquitos Laqoon by Pacific Texas Pipeline Company and the Port of Los Angeles . Mr. John Briggs, 2650 Camino Del Rio Worth, San Diego, representing Smis Corporation, stated they had been working on the lagoon enhancement plan for six mnths. He reported on one of the elements, which was a study from Scripps on the possibility of opening the lagoon to regular tidal action. David Skelly, 2440 Locust Street, San Diego, representing Scripps Institute, explained the methods used in mnducting the study of the lagoon. He stated the study is not complete, as they intend to measure tidal elevation at Carlsbad Boulevard, the railroad tracks, 1-5 and the middle of the lagoon, to determine how to keep the lagoon self-maintaining. John Walters, 4955 Ridgehaven Court, San Diego, representing George Nolte, stated he has been involved in a study o€ the lagoon for a number of years. He told of different plans for the lagoon area, including the present plans. Council Member Chick made a motion to approve the recomndation to have the City of Carlsbad be the lead agency and enter into a joint agreement with the Port of Los Angeles and direct the City Manager to prepare papers and documents to be brought back for approval. Motion died for lack of a second. Mayor Casler stated it was fortunate that Scripps had made this study. However, she felt Council should wait for the Conservancy report before entering into any agreement, as it was important to have all information first, Council Member Chick stated it was pssible that if Carlsbad did not indicate its willingness to take the lead agency role, that another site might be selected. He felt it was necessary to mve ahead rapidly. 4349 - \v 5 COUNCIL % 3 MEMBERS % c Casler Lewis Kulchin Chick X Pettine - , 0 MINUTES July 30, 1985 Page 2 Council approved the reconmendation for the City of Carlsbad to be the lead agency in pursuing the enhancement of Batiquitos Lagoon by the Port of Los Angeles and the Pacific Texas Pipeline Company, with the City Manager to investigate further Council actions , CONSENT CALENDAR: Council confirmed the action of the Consent Calendar, as follows: I I WAIVER OF ORDINANCE TEXT READING. Council waived the reading of the text of all ordinances and resolutions at this meeting. (81 ) 1. AB #8262 - ACCEPTANCE OF CONTRIBUTION FROM TOURNAMENT OF CHAMPIONS FOR PARAMEDIC TRUST FUND. Council adopted RESOLUTION NO, 8119, accepting a gift of mney for the paramedic trust fund. (81) 2, AB #8263 - ACCEPTANCE OF GIFT ON BEHALE' OF THE LIBRARY. Council adopted RESOLUTION NO, 8120, accepting a gift of book shelving for the Carlsbad City Library. (81 ) 3. AB #8264 - ACCEPTANCE OF A PORTION OF TAMARACK AVENUE. Council adopted RESOLUTION NO. 8121, accepting a grant deed from Margaret Brownley, conveying an easement for road purposes for a portion of Tamarack Avenue. (97) 4. AB #7577 - Supplement #4 - AIx;A WATI PRcxTEcT NO. (45) 3141. Council accepted the mnstruction of Alga Road Project No. 3141 as complete and directed the City Clerk to have the Notice of Completion recorded; and Council adopted RESOLUTION NO, 8122, approving an additional appropriation of funds for the construction of project no. 3141 - Alga Road. (50,) 5. AB #8265 - REFUND OF FEES. Council approved the refund of $600.00 to Tom Trevino; $545.00 to Ronald Wilson; and $550.00 to Michael and Vicki O'Gara, (81 ) 6. AB #8266 - ACCEPTANCE OF A POFCPION OF CHINQUAPIN AVENUE. Council adopted RESOLU!l?ION NO, 8123, accepting a grant deed for an easement for public access and utility purposes from Jack D. and Dorothy D. Hall, HOUSING AND REDEVELOPMENT COMMISSION: Council adjourned to the Housing and Redevelopment Cmission at 6:38 p.m., and re-convened at 6:45 p.m., with all Members present. 24Q \p 5 COUNCIL 3 % MEMBERS % f Casler Lewis Kulchin Chick X Pettine Casler Lewis Kulchin X Chick Pettine - 0 0 MINUTES :571 :551 :281 (281 145 1 \p 5 COUNCIL 3 9A July 30, 1985 Page 3 MEMBERS % q 7. AB #8147 - Supplement #I - HISTORIC PRESERVATION ElEMEWT TO THE GENERAL PLAN. Chris Salomne, Corranunity Redevelopment Manager, gave the staff report as contained in the Agenda Bill. He introduced the Chairman of the Ad Hoc Consnittee, Marge Hmard-Jones . Marge Howard-Jones, 3985 Park Drive, gave a brief history background for the City of Carlsbad and the historical sites in the City. She then narrated a slide presentation showing the different types of architecture in the City and some of the historical sites . Marylynn Brown-Bellman, 2638 Luciemaga, addressed Council, asking them to adopt the Historic Preservation Element. Kay Christiansen, 2802 Carlsbad Boulevard, gave a brief history of the City of Carlsbad, Council referred the Historic Preservation Element to Casler the General Plan with implementing draft ordinance to Lewis the Planning Cdssion for report and recomndation. Kulchin X Chick Pettine 8. AB #8219 - Supplement #1 - TRASH COLLECTION RATE STUDY. Bob Holmes, Chairman, gave the report of the Trash Rate Comittee, as contained in the Agenda Bill. Council Members mentioned a letter received today from a Committee rnember asking for other mnsiderations. Mayor Casler stated if any actions were to be taken on this letter, it should be at a future meeting. Council Mer Chick expressed disappointment with the structure of the connnittee and their refusal to deal with some of the issues, Council reviewed and approved the Trash Rate Cmittee Casler Reprt . Lewis Kulchin X Chick Pettine 9. AB #8267 - Ix>AN To REDEXEIDP" AGENCY FOR MAF!KEF FEASIBILITY STUDY. Chris Salomone, Comunity Redevelopment Manager, gave the staff report on this item as contained in the Agenda Bill, Council adopted the following Resolution: Casler X Lewis RESOLUTION NO, 8124, Al?P€XIVlX A LOAN TO THE Kulchin REDEVELOPMENT XENCY EOR A MARKET FEASIBILITY STUDY OF Chick THE REDEVELDPMENT AREA AND AUTHORIZING TRANSFER OF Pettine FuM>S. 10. AB #8628 - PUBLIC WORKS AGREEMENT - CARI;sBAD REDEVELOPMENT PROJECT. Chris Salomone, Cornunity Redevelopment Manager, gave the staff report as contained in the Agenda Bill. - 3 49 - c ( ( ~ 0 e MINUTES July 30, 1985 Page 4 Council adopted the following Resolution: RESOLUTION NO. 8125, AU'IHORIZING THE MECUTION OF A PUBLIC W3RKS ACWEMENT WITH THE CARISBAD REDEVELOPMENT AGEWCY RELATING 'IO PUBLIC IMPROVEMENTS IN 'IHE CARLSBAD VILLAGE REDEVELOPMENT PROJECT. 62) 11. AB #8269 - RESOLUTION ENDORSING WED FOR MEW LEGISLATION TO AID IN THE FIGHT AGAINST Low-FLYING AIRCRAFT ALQE COASTLINE, 62) 11. AB #8269 - RESOLUTION ENDORSING WED A_, LvY.. LEGISLATION TO AID IN THE FIGHT AGAINST Low-FLYING W ~~~ . ~ 0. Council approved the adoption of a resolution in opposition to low-flying aircraft, as presented in the Agenda Bill. CLOSED SESSION: : 41 ) 1 2. CIQSED SESSION - PENDING LITIGATION. Council determined to hold a closed session pursuant to Government Code Section 54956.8 to give instructions to Marty Orenyak concerning negotiations with John Chabot (or his agent) for 30,340 square feet of land located at 2742-52 State Street, AP 203-181-19. Council adjourned to a Closed Session at 7:30 p.m. Council re-convened at 7:59 p.m., with all Council Members present. Mayor Casler announced that Council instructed their negotiator on the acquisition of the property, ADDITIONAL BUSINESS: Insurance Council Member Pettine requested clarification of Council action at the previous meeting regarding Council direction to shop the insurance contract. The City Manager stated that Council had directed that The Wyatt Cobnpany be retained to prepare the employees' insurance program and to submit proposals from other insurance companies. Further, that the program would contain the same benefits. 7- The City Manager additionally suggested that the City solicit other insurance consultants for proposals for preparation of the bid documents. Mayor Casler stated this should be on a regular agenda for discussion. COUNCIL REmm : Senior Citizen Association Council Member Lewis and Mayor Casler reported on the last two metings. 246 \v 5 COUNCIL % 94 MEMBERS % f 1 Casler Lewis Kulchin Chick X Pettine Casler Lewis X Chick Kulchin Pettine Casler Kulchin Lewis X Chick Pettine 1 - c * m MINUTES \? 5 COUNCIL % 9A July 30, 1985 Page 5 MEMBERS % f City Attorney Additional Business The City Attorney reported that Council Memhers Rulchin and Pettine had inquired regarding a letter received by some City residents from the Manager of North County Resource Recovery Associates containing a notice of eligibility for a Homeowner Protection Plan. He stated he learned that the City of San Marcos required the developer to offer a homeowner protection plan as one of the conditions of approval for the plant. He explained that participation in the plan requires the homeowner to pay $125.00 for an appraisal of their home. Then, if the home is sold within five years for less than that appraised value, the developer will either buy the home, or pay the difference between the sale price and the appraised amount. If the price goes up, however, the developer gets 50% of the appreciation. In essence, the homeowner signs an agreement which is recorded and becomes a lien on the home. In conclusion, he stated that participation in the plan is a private contractual arrangement between the developer and homecwner. Further, if questions are directed to Council Members, they should suggest that the homeowners mnsult with their personal attorney. AI": By proper mtion, the meeting was adjourned at 8:20 p.m. Rspectfully submitted, WR. - ALExwA L. RAUTENKRANZ City Clerk Harriett Babbitt Minutes Clerk 6\45 <Vr' ALTERNATIVES FOR MAINTAINING TIDAL CIRCULATION IN THE BATIQUITOS LAGOON, CALIFORNIA JULY 1985 BY Scott A. Jenkins, Ph.D. and David W. Skelly, MS. CENTER FOR COASTAL STUDIES SCRJPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA, CALIFORNIA Alternatives for Maintaining Tidal Circulation in the Batiquitos Lagoon, California by Scott A. Jenkins, Ph.D. and David W. Skelly, MS. Center for Coastal Studies Scripps Institution of Oceanography La Jolla, California I. Sea Level and Tidal History Batiquitos Lagoon is a feature of the most recent period of the Pleistocene Epoch. In fact it did not exist as a lagoon structure as recently as 18,000 years before present. Figure 1 shows the sea level variations for Southern California over the last 40,000 years of the Pleistocene Epoch. We note that sea level was about 120 meters below its present level at the end of the Mid-Wisconsin Regression. Thus Batiquitos Lagoon was "high and dry" 18,000 years ago. It Was not in fact a lagoon then, but rather a stream valley cut in the Linda Vista Terrace. Following the melting of glacial ice at the end of the Mid-Wisconsin Regression, sea level gradually rose to nearly its present level some 6,000 years before present. This sea level rise drowned the seaward end of the San Marcos river valley, thus forming the Batiquitos Lagoon system. During this sea level rise, fluvial material filled the floor of the San Marcos River valley with sand and gravel deposits up to 10 meters thick (Inman, 1983; Inman and Jenkins, 1983). During the last 6,000 years, the rise in sea level has been very slight, about 15 cm per century. However the fluvial deposits of sediments on the lagoon floor has continued, steadily reducing the mean depths and tidal prism of the lagoon. Whatever species utilize the lagoon as a MSL 0 50 3 £. too J I 35 30i i i i i i 25i Thousondi ol Yeori Before Present 1520i i i 150-J Mid-Wisconsin Tronsgression Mid-Wisconsin Regression Flondrlon Tronsgression -IOO Modern -< L|50 Figure 1. Late Quaternary fluctuations in sea level. Solid line is the "generalized" sea level curve (from Curray, 1965); dashed line is detailed curve for northwestern Gulf of Mexico (from Curray, 1960; 1961). -3- shallow water breeding ground must be relative newcomers to the lagoon, sometime during the last 6,000 years. In fact, prehistoric La Jolla and Del Mar Man have had a presence around the lagoon and neighboring river valleys even before this time (Masters, 1983). In modern times, sedimentation in the lagoon has taken a rapid up- turn due to Man's development of the San Marcos River valley and the construction of the road beds for the railroad, Highway 101 and the Interstate-5 Freeway which directly encroach on the lagoon. These developments are summarized in Table #2 together with recorded rainfall and the sources for these records. Periods of heavy rainfall concurrent with some of these man made developments resulted in higher erosion rates and episodes of high sedimentation in the Jagoon. The corresponding reduction in tidal prism (the volume of water exchanged between the lagoon and the sea in one tide cycle) has been dramatic. Table 1 gives a listing of tidal prism estimates for Batiquitos Lagoon as a whole with separate estimates for the west basin (west of 1-5) and east basin (east of 1-5), from 1887 to 1978, based on work by Gayman, 1978; and Inman and Frautschy, 1965. Table 1: Loss of Tidal Prism at Batiquitos Lagoon 1887-1978 Year 1887 1888 1960 1965 1978 Tidal Prism West Basin (meters) 3 g2.15 x 10b c1.85 x 10° g1.63 x 10° g1.34 x 10° Tidal Prism East Basin (meters)^ 2.17 x 1.86 x 1.66 x 1.43 x g10b g10b g10b g10b Tidal Prism for Total Lagoon (meters) 3 g 4.32 x 10° g3.71 x 10° g3.29 x 10° g2.77 x 10° 9.43 x 103 GRAPHIC RECORD OF HISTORIC EVENTS . CLIMATIC RECORD AND OTHER OCCURRENCES PERTINENT TO THE TIDAL HISTORY OF BATIQUIJOS LAGOON I05O I860 '1870 1080 IQ90 1900 1910 1920 I93O 1940 I95O I960 7970 BED HISTORIC MOSIGNIFICANTEVENTS MAPS c(OH h'.AP M.-.JOR FLOODS DHXSEtSiNG CRKR0? MAGNITUDE A\".:1JAL RilMFALLCITY OFSAN OI£CO CSY ANDV.'ilT PERIODS CONSTRUCTIONANDDEV£XOr:/£NT LAND USE 1 1 1 1 1 1 1 '"'fu'ssgEG0 I-LAMO CnAI.'lS iB'fhrK^ZRCLST jcj^ffL^rca, 1 1 1 1 1 1 1 1 1 Tninn •'. '-'.ExiCAM pn HANOO ,1, 115 REY I-?GU\' '"Cw^If IOO YR AVER \\tT tltAZlNG (CATTLE *f;D SMECP)I 1.1 i ii i i i i °r .CtMITOS..c/v;>>.:..'iA eccav.ES l-VflCELER I-UJC6GS1 SUrtvET 1 10 7 S 56 6 KO • 10 15 J7JOI8 15 iOE • 100" _ 1 11 AKOliKE 1 1 1 ' 1 1 1 1 1 1 ' 1 STATE »flGHV;AY 101JiNCf&OCO HIOr.VAY O 1 'CHAWING5l» hOAO .-MTRAIS i \.j AFRIAIMTaicT Q<M-I:« 1 P,OIOSH.*H SiN WtRCOSCftEEK fLOOO, • O HOO • O ODD X^ 9 K 2 11 II 4 18 . 12(7 16 12 7 6079 28 6 866 J \ } t 1 1 1 1 1 1 H88WP I-Z6UIB* o 15 6 I *1 JUvra-Lnj-^-n- r 111! HIGHWAY lOt l-RilL^CiO Rt-AtlEK'UENT ^-^-{nenioGC t-moK-.vif o< OC^STB (vc-vsyssE) VsyviGt. . (i'i v 1 K?v.' '-LAND FILL LfiGrvSr'^ CJS-H.1RG£[-»"AS V-HrSAl'/iY IOI ItrtioSt j-l-5 FKEEV/AY BRiDGt ^ |_ gj^ gjp-j-j rjiCEK Table 2. From G.G. Kuhn (in prep) <*.OL\V.V ' ' -•:• •: ••.-.V" •• '.:. '.•••.v". '\, *-•-•- ••• . •„., • .'• ... M•:* '••• ;;v^Me'*-o;o '•-!:^^i^y-.uc-;t< -: ••-. A/r-v\'mi*^ •• /^- •• v. •*• •^4W^-;/:^^^^,:'. :•'< -!>\4v>$w$<ti;$<f* .•*&*'< s .-J^1'-" "-' v ,-v, .-»..».,•.. ,v» • ..."^MrtvV'^A • ic-4* -v • v .•••'•• >: '••; j• '.•''. ,•••''•>;.'••»• v -v. ; !i'«.f.V .v\x\!,rk'>' >..\. 'si^-1 ; • .'•• v* ' -W ,,v.h-i >''-v ..:;•. ... •.'(• 'VA."-N\ '• .»/?.•»" ;•i>.,"U V / ,."'•»"• .;.;•... --^^^vuSv :• i.^,*'-1* •• •-'• •' •••/ '^UV:r:^M-«:;';M--v:::.,.'v •' -. SCALE: I'11 = 2000'» . ...... • .' >• '••\. > ' V- "•'. '. .•.M.;,V: '.;:'•••••;» \-...;-':, '.I''.'.••, '/.JVt.A-i.V:'.;;.,.. .}•••• >' ;- ...',. ., i ;. \?•:>«..•!»>••('•\ T • i • , 1 -i*> v) • •:• >• V- • i. '. ,-\ i • U. .'t.ip y-i \,a^\^^v*i|a:M^u%-ir -:A*A1':.- '"''' Figure 2 California Southern Railroad Map, 1881. Three parallel lines indicate proposed railroad route. Note 3000 ft. long south tidal channel and 1100 ft. north channel. Lagoon Entrance channel is about 6-700 ft. south of present highway bridge. -6-BEST QMGINAL :.<-tv.C*rv - v .A •' :vi . - • .:-.v- ••;-__> •--.• j. '• ^ -:^^-r .-.--r-vv. • -..^-^^=L-C-> ^ SCALE: 1" = 2000' Figure 3. U.S. Coast & Geodetic Survey 1887-8 Map (#1899) of northern half of Batiquitos Lagoon. No entrance channel is shown. Reduced copy is not too clear, but suggests road may run across beach between lagoon and ocean. Note 3300 ft. road (or wagon track) across northern lagoon embayment. O SCALE: 1:62,500 Figure 4. U.S. Geological Surgey Map, Oceanside 15' Sheet 1898 clearly shows no channel connecting lagoon with sea. Road without bridge runs between lagoon and the ocean. V Figure 5. Lagoon area map showing the total acreage and the bridges at Carlsbad Blvd., the Santa Fe Railroad and Interstate 5. -9- We find that Batiquitos Lagoon maintained an excess of 3 x 10 meters of tidal prism up until the mid-1960's. Historical photos and surveys indicate a natural open inlet throughout most of this period. A detailed analysis of the inlet configuration shown in historical survey data is contained in the University of San Diego Report, 1978. The inlet channel was permanently stabilized at the northern side of the lagoon by the construction the Highway 1 bridge in the late 1920's. Before bridge construction the inlet channel would naturally move back and forth between the adjacent headlands. The movement of the inlet channel was caused by wave climate changes and the consequent changes in longshore transport rate and direction. Figure 2 shows the inlet channel near the southern headland. Figures 3 and 4 not only show no inlet channel but show a road across the lagoon entrance. With rapid development of the drainage basin from the mid 1960's on, combined with record rainfall and flooding during the winters of 1977-78, 1979-80 and 1982-83, the tidal prism of the lagoon has suffered a drastic reduction. The records of the aerial photo bank indicate that the inlet to the sea under the Highway 101 and railroad bridges was open only sporadically at the reduced tidal prisms during the 1970-80 period. The inlet sill depth plays a critical role in determining the magnitude of the tidal prism. Only that portion of the tidal excursion laying above the inlet sill depth will force an exchange of water between the lagoon and the sea. Batiquitos Lagoon has two such critical sill depths, one beneath the Highway 101 bridge and the other beneath the 1-5 bridges. The road bed of these two bridges constrain natural adjustments to the sill depths, see Figure 5. 10 15 9 - 14 UJ 6 1 • 0 1 13 ho} 12 10 * BATIQUITOS LAGOON TIDES 1 1 1 1 I I I 1 1 1 1 1 1 1 1 0 15 BRIDGE RR BRIDGE PIER • / •\ \ i ; \ \ //1*' , •. /\ \ , 1 1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 ' I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I 024 6 8 10 12 14 16 18 20 22 24 2 4 6 8 10 12 14 16 18 20 22 24 2 4 6 8 10 12 14 16 18 20 22 24 P.4FEB80 25FEB80 26FEB80 (NOAA Tide Stations #9410339, #9410342 and #9410230.) i o Figure 6. Spring Tides over three day period when lagoon was open to tidal action in 1980. -n- The resultant effects on tidal range inside the lagoon is clearly shown by tide gauge measurements taken in 1980 and plotted in Figure 6. The tidal variation measured in the west basin beneath the railroad bridge follows the tidal variation in the open sea as measured at Scripps Pier, with about a one-foot attenuation in tidal amplitude due to frictional losses through the inlet. However, the tidal variations at the 1-5 bridge are flat over the low tide portions of the records with no change below -1.0 ft MSL. Thus the sill depth in front of or beneath the 1-5 bridge must be about -1.0 ft MSL with the effect of greatly diminishing the tidal prism in the east basin. Since the lagoon was receiving flood runoff during this period, these tidal variations are more representative of a "best case" from the standpoint of tidal exchange in the lagoon during the recent past. During the summer months no exchange at all occurs beneath the railroad bridge. Figure 7 is a photograph of the lagoon in late July, 1975 showing the inlet channel clogged with sand and mud flats beneath the railroad bridge. Figure 8 shows the inlet channel when there is some exchange of lagoon and ocean water during high tides with wave overwash. Figures 9 and 10 show the lagoon when it is open to tidal action with the sill at about MSL. Besides inlet(s) sill depth, tidal extremes will also periodically alter the tidal prism of the lagoon. Figure 11 gives plots for the extreme high tides for several locations on the California coast from 1983 until the year 2000 (Cayan and Flick, 1985). From the standpoint of maintaining tidal circulation and an adequate tidal prism, the times of greatest concern are the minimums, e.g., 1987, 1991, 1995, 1996 and 2000. At these times the amount of tidal range above the inlet sill depths will be the smallest, and the tidal prism and tidal circulation will be minimal. This is of particular concern to the inlet(s) themselves. If high waves Figure 7. Aerial photograph taken July 31, 1975 showing the lagoon entrance channel plugged with sand. (Aerial Photobank, Sorrento Valley, CA.) /3 c>$*«T . "* f J ^ Figure 9. January 27, 1979. (Aerial Photobank, Sorrento Valley, CA.) Figure 10. January 1, 1985, (Aerial Photobank, Sorrento Valley, CA.) ' PREDICTED EXTREME HIGH TIDES fl 9.0 r 8.0'- 7.0 6.0 L- 7.0 6.0 L HUMBOLDT crii LOS ANGELES 1983 1984 1985 1986 1987 1988 1989 1990 199! 1992 1993 1994 1995 1996 1997 1998 1999 2000 Figure 11. Plots of predicted extreme high tides 1980-2000. -17- happen to occur at these same periods when tidal flow and scour through the inlets is smallest, than the inlets may permanently close. II. Inlet Processes A natural inlet maintains a precise equilibrium with the tidal prism which is dependent upon the amount of wave power that is directed along shore. A natural inlet maintains its stability through a steady state balance between tidal scour and wave induced sand transport. This balance may be expressed in terms of the energy fluxes associated with these two competing processes. If the energy delivered longshore by wave action during the flood phase of the tide cycle is less than the energy available in the ebb flow of the same tidal cycle, than the inlet will remain open. The wave energy varies as the breaker height H. , and breaker angle,oC» whereas the ebb flow energy is dependent upon the tidal prism V and the tidal range above the sill depth, ~r. Thus there is a minimum tidal prism V . , that will maintain an open inlet under attack by waves of a given height and direction. Following the work by O'Brien 1980, the minimum tidal prism is given by 2T.-W Hr; Cn sine*. cosoC V - F b (1)vPmin - u; where TF is the duration of flood tide, C is the group speed of the breaking waves and W is the constrained channel width as determined by the available span beneath the bridges = 43.8 meters. There is no possible unique answer for a minimum tidal prism from equation (1) since the wave climate and tidal ranges will vary in time as independent random variables. Instead we calculate a minimum tidal prism for a set of recurrence intervals of closure based on wave and tide statistics -18- (thati.s the time between inlet closure if the tidal prism were a particular value). To do this, deep water wave statistics published as occurrence tables in DNOD (1977) and Marine Advisors (1960) were shoaled to Batiquitos Lagoon inlet on a digital computer using a linear ray shoaling trans- formation adapted from Dobsen (1967). The resulting shoaled breaker heights, directions, and group speeds after accounting for directional island shadowing effects from San Clemente, Santa Catalina, San Nicolas and Santa Barbara using a data adaptive technique from Pawka, et al., 1982, are tabulated in Appendix Tables Al through A12. Fortunately the largest waves and lowest tides seldom occur simultaneously. For this reason the minimum tidal prism for a given closure recurrence interval is less than the sum of the individual components (waves and tides) for the same recurrence interval. Instead, the recurrence interval of closure for a given minimum tidal prism must be calculated from the individual probability distribution using a double convolution integration given in Papoulis (1965), The results are found in Table 3, Table 3: Recurrence Interval of Inlet Closure for a Minimum Tidal Prism at Batiquitos Tidal Prism Vpml-n (meters) 3.12 x 106 3.05 x 106 2.72 x 106 1.89 x 106 8.24 x 105 3.26 x 104 Recurrence Interval of Closure, years 30 20 10 5 1 0.2 -19- Th us the pre-1960 values of tidal prism for the combined east and west basins of the lagoon are all above the critical minimum necessary to maintain the inlet open to the sea against attack by the largest waves and minimum tides recurring every 30 years. Comparing Table L-and Table 3, we find the present small tidal prism will result in inlet closures about five times each year. It should be remembered that such statistical manipulation is better suited for identifying trends rather than absolute values. The figures in Table 3 do however support the available survey and photo evidence. Having identified the approximate size of minimum tidal prisms which will maintain an open inlet against wave attack, we can now specify the required inlet cross sectional area. The relation between tidal prism and inlet cross section has been understood for some time. O'Brien (1931) was one of the first to show this relation plotted in Figure 12 but with limited data. Inman and Frautschy extended this to values 0 (106m3) and below, and Inman and Harris (1966) found additional supporting data. Reading Figure 12 for the value of a 30-year recurrence closure, V = 3.12 x 106 m3, we find that an inlet cross-section of 2215 m would be required. III. Methods to Maintain Tidal Circulation Two basic approaches are offered to maintain tidal circulation in the west basin of the Batiquitos Lagoon. These are equilibrium and non-equilibrium methods. Equilibrium methods basically involve restoring sufficient tidal prism to maintain the lagoon entrance by natural tidal scour. Non-equilibrium methods involve power augmented systems to maintain an open lagoon in spite of a non-equilibrium configuration. The primary motivation for non-equilibrium methods is to avoid excavation of large volumes of material. I05 San Francisco Bay Columbia R. .. Willapa Bay . no4 - LJ 22 < I O UJ O ABSECON INLET Gray's Harbor . San Diego Bay •jHumbolt Bay Coos Bay .oQui Nhon Umpqua R . / xjillamook Chu Lai '/ Absecon Channel ^ X, »H.ue I0 2 UJ O Main Channel- Coquille Newport Bay »v >i»Yaquina Bay ,AJ\lehalem R. Mission Bay (Mar. 1954) ro oi UJtr I02 'Gamp Pendleton (Feb. 1956) • DIURNAL RANGE A MEAN RANGE a TROPIC RANGE J L 1 ' 1 ' ' 1—L.• • i 1 L. 10 =I06 I07 I0e TIDAL PRISM , M3 10s 1010 Figure 12. Tidal prism versus inlet area (Inman and Frautschy, 1965; Inman and Harris, 1966). -21- A) Equilibrium Method According to Table 2, excavation of the 'lagoon to create a tidal fi ^prism of 3.12 x 10 m will essentially restore a self-maintaining inlet. Considering the existing tidal prism, this would require excavation of fi "34.07 x 10 yd from the lagoon system. If both the west and east basins are included together in this excavation, it appears feasible to remove this large volume of material without endangering California Least Tern nesting sites. One possible scheme would not disturb the existing perimeter region of the lagoon above the +3.5 feet MSL contour. Below the +3.5 feet MSL contour, the bank would be graded downward at an average slope of -3% until -5.0 feet MSL is reached, where 0 feet MSL corresponds to +2.88 feet MLLW. Along the existing stream bed and flood channel the bottom will be maintained at -5.0 feet MSL to form a flood channel of at least 144 feet in width. In certain bottleneck sections of the lagoon there will have to be local bank slopes steeper than -3% in order to maintain a flood channel of sufficient width at -5.0 feet MSL depths. The resultant excavated volumes by this scheme are about 1.0 million cubic yards removed from the west basin and 3.0 million cubic yards from the east basin. In the process a wetlands belt whose average width is about 180 feet is created between the MLLW and MHHW shore contours inside the lagoon. On the other hand a sufficient deep water cross section is maintained in the tidal channel to permit tidal flux without extreme bottom friction losses. The borings conducted in the east and west basins by Woodward and Clyde, 1985, indicate three-dimensional sedimentary deposits in the portion of the upper two feet of this proposed excavation containing significant fractions of fine silts and clays. This material totaling about 581,000 cubic yards will have to be dispersed in landfill sites. The remaining fi }sediments in the proposed excavation, totaling about 3.488 x 10 yds , are suitable sand sized material (0.16 to 0.25 mm) for beach nourishment. -22- Thus the high costs of excavating such a large volume of material could be offset by selling that material to neighboring communities who are suffering extreme beach erosion. If these communities are not capable of accepting part or all of the suitable sand fractions at the time of excavation, then that material could be stored as a vegetated beach dune behind the berm crest of the beaches in the immediate neighborhood. The excavation should take place during the summer months when the lagoon is dry. A dry lagoon would enable large earth moving equipment to remove a considerable amount of material at one-fifth the cost of dredging. The earth moving equipment will be effective only down to the water table and then clam shell or dredging will be required. The dredging would proceed systematically from west to east utilizing the ocean as a water source. Because the lagoon is partitioned into three sections by the bridges there will most likely be three dredge mobilization costs ($200K-$300K each). Even though there is no reason to expect the dredge spoils to be contaminated they will need to be analyzed for EPA priority pollutants (organics and trace metals). There are EPA certified labs in the area who will know the required number of samples and analysis procedures. The top few feet of the lagoon sediments are silty clays which can be used for fill in the adjacent developments. The sand beneath this silty clay can be sold for beach nourishment. B) Non-Equilibrium Methods Bull-dozer and Pilot Channel: This is the most common stop-gap method in use on both coasts today. For one reason or another, the minimum tidal prism cannot be restored and the inlet closes on a regular basis. Evacuation of only 1.065 x 10 yds will result in an inlet closure about once every year. However, a pilot channel dug by a bull-dozer at low tide -23- 5 3will release a prism of 8.3 x 10 meters that will scour open a channel Pwith 72 meters cross section. This channel should remain open for another year under statistically normaly seasons of waves and tides. The bull-dozer must remain on standby since the time of the next closure is uncertain. The required dredged project depth for this method would be -5.04 feet MSL for the 131.2 acres comprising the west basin. The channel depth that would maintain the required cross section and yet fit between the 144 foot span of the Carlsbad Blvd. bridge would be at -5.38 feet MSL. Because of the bridge clearance a smaller piece of earth moving equipment such as a "bobcat" will be required to work beneath the bridge. The smaller equipment will feed the bulldozer which will in turn push the material to the downdrift beach. C) Fluidizer System with Jetties This approach has the same dredging requirements as the bull-dozer pilot channel method. It would use a permanent fluidizer/eductor system to maintain the channel against periodic closure (Jenkins et al., 1980). It requires two 400 foot long jetties which span the beach berm and protect the system from ingesting cobbles. The entrance will be artificially narrowed by placing the jetties at 106 feet apart, yielding maximum flood currents of 89 cm/sec. Thus the jetties are also required to prevent bank erosion. However the high flow speeds prevent shoaling of longshore transport in the channel. Instead a shoal will result inside the lagoon as the flow diverges and the suspended load is deposited. The fluidizer system is placed on this shoal where it is protected from direct attack by waves. The fluidizer system is shown schematically in Figure 13. It consists of a pipe with high pressure jets injecting water into the shoal, causing it to form a slurry which moves readily down shallow gravity slopes. At the base of the shoal an eductor pump collects the slurry and pumps the CRATER- SINK WATER LEVEL- INJECTION WATER FLUIDIZING PIPE '\ ,SAND FLOW BUNDER PIPE •WATER LEVEL INITIAL SURFACE ',f|fi*W SURFACE \ S / ,' .'' ' l|f l' I i i ' \>—^f t ' t D I D C l!'1 l *" ' ' i i ' * '' . i '' , ' t V' '. '* IV t, i J' , i' f»\ .^ ''l':jv !';;OUCT' 'FLOW •.',•;.," .•; (^'^:^'' 1,., v , >' ' ,\i, *'',') '* A" % Figure 13. Schematic diagram of duct-flow fluidization: (A) angled water jets from bottom nozzles in the fluidizing pipe suspend sand and move it along the oval duct formed beneath the pipe; and (li) sand feeds down the natural angle of repose (about 30°) perpendicular to the fluidized duct. As the sand enters the duct it is carried along axially and finally dis- • . charged into deeper water or into a crater-sink, (from Bailard and Ionian, 1975). rv>-c»i -25- sand back to the downdrift beach which will normally be that portion south of the jetties. The nominal longshore transport of sand which the fluidizer must bypass across the inlet in this manner is 215,000 yds . The pumping system required to bypass this amount of 0.2 mm size sand would have a 2,000 gpm flow rate and operate a 158 hp at a todal head of 244 feet. The fluidizer pipe required would be 6" diameter and 400 feet long, having 1,920 jets, each with a diameter of 0.064 inches. Figure 14 shows the water jets and fluidizer pipe used to open the Los Penasquitos Lagoon in May 1977 (Figure 15). D) Drag Bucket and Pier With this method a very small design tidal prism is chosen while 3"brute force" is employed to maintain the inlet. As little as 30,000 yds could be excavated from the west basin. Closures of the inlet could be expected about five times annually, perhaps more. A 400-foot long pier is built from the Highway 101 bridge out across the surf zone. A mobile crane is operated from the deck of the pier which drags a bucket from the lagoon, seaward. The material dug from the inlet channel is deposited in the surf zone where longshore transport by waves moves the material away from the inlet. Since no hydraulic equilibrium is involved, any arbitrary channel depth and width which permits tidal circulation may be chosen. E) Syphon This method abandons an open channel inlet to the lagoon altogether. Instead a 6.0 foot diameter syphon pipe is buried at -2.0 feet MSL between the lagoon and the 025 feet MSL contour on the ocean side of the inlet. Tidal variations in the ocean side will circulate water in and out of the lagoon. The concept requires as little as 30,000 yds of excavation to the present lagoon. However, it has a practical limitation due to biofouling. A killing agent of some sort is required. Back flushing with hot water ;-26- f£-~" •"•'• 'K-VvV vvrt*-- '.-.&*. _>*-. \_ •- ""-^^M^E»»u.i.-i -• -tliSiuft*,:- ,k 7-^.'.'--.>tj<s: Figure 14. Figure 15. -28- is commonly done by coastal power plants. Anti-fouling paints are not environmentally acceptable. Two pipes with one being reamed while the other functions as a syphon was used successfully by Scripps Aquarium. The long term maintenance costs of reaming are a serious detraction to this approach. VI. Effects of Salt Water Flux from the East Basin. A plan for restoration of the east basin of Batiquitos Lagoon has been advanced that will impact the west basin alternatives for maintaining tidal circulation to the extent that relatively small quantities of high salinity water will be introduced. According to the recent version of the east basin plan, the two basins will be partitioned by a weir situated near the 1-5 bridge as shown in Figure 5. Because of this weir only that portion of tidal prism held by the west basin will be free to circulate with ambient sea water through the inlet under the Highway 101 bridge. Ground water of about 34 /oo salinity will be pumped into the east basin at a rate of 4,000 gallons per minute. This flow rate is roughly three times the evaporation rate over the acreage of the east basin. Because evaporative losses are replaced by 34 /oo salinity ground water, the salinity in the east basin will exceed the ground water salinity. To stabilize both the water level and the salinity in the east basin during the dry summer months, approximately 2,666 gpm must be passed continuously over the weir from the east basin to the west basin. This action will stabilize the salinity in the east basin near 50 /oo. In the winter months, the salinity in the east basin will be considerably less than this due to the infusion of fresh water runoff from Pacific storms. The pumping of ground water and the bypassing of water from the east to the west basin can be greatly reduced, cutoff altogether, or regulated according to the design water level. -29- Thus, the greatest potential adverse effect from the east basin restoration plan appears to be the flux of 2,666 gpm of 50°/oo salinity water introduced over the weir into the west basin during summer months. This will have the greatest effect on salinity elevations during the flood tide interval when the west basin is holding water. The longest durations .of flood tide occur near the railroad bridge and have been observed for as long as eight hours. The west basin could therefore receive and hold as much as 6,338 cubic yards of high salinity water, before releasing it into the sea with the insuring ebb tide. The amount by which salinities are elevated in the west basin during this time depends upon which of the alternatives outlined in the previous section are implemented. If the equilibrium methods are adopted in the west basin, then 4.081 x 106 yds3 of 32°/oo ambient sea water will mix with 6,338 yds3 of 50°/oo bypass water during the flood tide phase. As a result, the salinity in the west basin will be elevated to 32.028 /oo by the time ebb tide insues. This is a negligible amount of salinity elevation, only 28 ppm, and is barely measurable with a standard Beckman analytical salinometer. If non-equilibrium methods are implemented, then somewhat higher salinities result in the west basin near the end of the flood tide phase, For either the bull dozer or fluidizer plan, 1.077 x 10 yds of 32 °/oo sea water will mix with the high salinity water released from the east basin. This will elevate salinities in the west basin to 32.105 /oo, or an increase of 105 ppm above ambient sea level. If the Pier and Drag 4 3line or the Syphon method is implemented, then as little as 4.23 x 10 yds of 32°/oo sea water will mix with the high salinity discharge from the east basin. The resulting salinities will rise by the end of flood tide in the west basin to 34.34°/oo, an increase of 2.34°/oo. This much salinity elevation during the insuing ebb flow may have measurable effects on the local marine communities. -30- In conclusion, the large tidal prisms afforded by the equilibrium methods serve as a dilution basin to buffer the beach ecology from the effects of high salinity discharges from the proposed east basin plan. The non-equilibrium methods have much less dilution capacity. Some damage to organisms populating the neighboring beach seems possible for the small tidal prisms associated with the Pier/Drag line method or the Syphon method. This damage could be mitigated by increasing the project dredge volumes above projected minimum values of 3 x 10 yds . How much additional dredge volume would be needed cannot be determined until lethal salinity levels for the beach ecology are established. -31- PRELIMINARY COST ESTIMATES 1. - Equilibrium Method 6 3Remove 4.07 x 10 yd (Can remove about 581,000 by earth moving, can dredge about 3.488 x 105). a. Remove 581,000 yd by earth moving equipment @ .70/yd3 $ 406,700 b. Dredge 3.488 x 106 yd3 @ $4/yd3 • 13,952,000 c. Total Excavation Estimate Cost 14,358,000 d. Value of removed sediments 3.488 x 106 @ $2.50/yd3 8,720,000 e. Net cost $ 5,638,000 .2. Bulldozer and Pilot Channel Method Remove 1.065 x 10 yd 3a. Remove approximately 300,000 yd by earth moving equipment @ $ .70/yd3 210,000 b. Dredge 765,000 yd3 @ $4/yd3 3,060,000 c. Sell removed sands 765,000 yd3 @ $2.50/yd3 1,912.500 d. Net cost to remove 1.065 x 106 yd3 $ 1,357,500 e. Bull doze opening channel 5' x 40' x 100' Approximately $2,000.00 per opening 3. Fluidizer Method- ~~~ fi "3Remove 1.065 x 10 yd •a. Remove approximately 300,000 yd by earth moving equipment @ $ .70/yd3 210,000 b. Dredge 765,000 yd3 <? $4/yd3 ' 3,060,000 c. Sell removed sands 765,000 yd3 @ $2.50/yd3 1,912.500 d. Net cost to remove 1.065 x 106 yd3 $ 1,357,500 e. Fluidizer to maintain channel (1) System cost $ 14,300 (2) 4 man days labor per opening and minor energy costs Preliminary Cost Est. Page Two -32- f. Jetty Construction 2 & 400' (1) Materials 12,000 tons of 5-ton rock $ 240,000 (2) Mobilization, design installation $ 100.000 $ 340,000or $375.00/ft. 4. Pier and Drag Line Method 43'Remove 3 x 10 yd and build pier a. Dredge 3 x 104 yd @ $4/yd b. Pier construction c. Dragline system d. Maintenance 50 Syphon Method 4 3Remove 3 x 10 yd and syphon a. Dredge @ $4/yd b. Syphon system c. Maintenance $ 120,000 515,187 30,000 approx 8,000/yr. $ 120,000 3,000,000 10,000/yr or more REFERENCES Bailard, J. A. and D. L. Inman, 1965, "Analytical model of duct-flow ' fluidization," Proc. Symp. on Modleing Techniques, ASCE, San Francisco, CA, p. 1402-1421. Bailard, J. A. and D. L. Inman, 1978, "Opening tidal inlets using sand fluidization," NOAA Sea" Grant annual report, Scripps Institution of Oceanography. Benton Engineering, Inc. , 1964, "Soils Investigation, La Costa Beach Inn, West of Highway 101, North of Leucadia, California" prepared for Tracy Price Associates, Planning, Engineering, Architects, 21 pp. Bruun, P. 1966 Tidal Inlets and Literal Drift, Norway. Cayan, D. R. and R. E. Flick, 1985, "Extreme Sea Levels in San Diego, California, Winter 1982-1983," Scripps Institution of Oceanography, University of California, SIO Reference No. 85-3, 58 pp. COE LAD, 1971, "Flood Plain Information San Marcos Creek, San Diego County California," U. S. Army Corps of Engineers, Los Angeles District, April 1971, 30 pp. with plates and appendices. Costa, S. L. and 0. D. Isaacs, 1975, "Anisotropic sand transport in tidal inlets" Proc. of the Symposium on Modeling Techniques, ASCE/San Fran- cisco, CA Sept. 3-5, 1975 p. 254-273. Curray, J. R., 1961, "Late Quaternary Sea Level:! a discussion", Geoldgical Soc. Amer.. Bull., v. 72, n. 11, p. 1707-12. Curray, J. R., 1965, "Late Quaternary history, continental shelves of the United States", p. 723-735 in H. E. Wright, Jr. and D. G. Frey (eds) The Quaternary of the United States, Princeton Univ. Press, 922 pp. DNOD, 1977, "Deep water wave statistics for the California Coast, Station 5." Department of Navigation and Ocean Development, Sacramento, California, 37 pp. Dobson, R. S., 1967, "Some applications of digital computer to hydraulic engineering problems", Tech. Rep. No. 8£, Dept. of Civil Engineering, Stanford University. Gayman, W., 1978, "Estimation of Present and Past Tidal Prisms in Batiquitos Lagoon," June 3, 1978, 17 pp. Harris, R. W., D. L. Inman, J. A. Bailard, and R. L. Oda, 1976, "Study and Evaluation of Remedial Sand Bypassing Procedures," U. S. Army Engineers Waterways Experiment Station Contract Report H-76-1. Hagyard, T., I. A. Gilmour, and W. D. Mottram, 1969, "A Proposal to Remove Sand Bars by Fluidization," New Zealand Journal of Science, , v. 12, p. 851-864. Inman, D. L., 1983, "Application of coastal dynamics to the reconstruction of paleocoastlines in the vicinity of La Jolla, Calif.," p. 1-49 in P. M. Masters and N. C. Flemming (eds) Quaternary Coastlines and Marine Archaeology, Academic Press, London, 641 pp. Inman, D. L. and J. D. Frautschy, 1965, "Littoral Processes and the Development of Shorelines," Coastal Engineering. (Santa Barbara Specialty Conference), Amer. Soc. Civ. Engrs.. p. 511-536. Inman, D. L. and R. W. Harris, 1966, "Investigation of sedimentation and dredging requirements, various locations, Republic of Vietnam," prepared for U.S. Navy, OICC Republic of Vietnam, under contract by 78944 with Daniel, Mann, Johnson and Mendenhall, Saigon, 237 pp. Inman, D. L. and S. A. Jenkins, 1984, "Oceanographic Report for Oceanside Beach Facilities," prepared for the City of Oceanside, 266 pp. Jenkins, S. A., D. L. Inman and J. A. Bailard, 1980, "Opening and Maintaining Tidal Lagoons and Estuaries," Proc. 17th Conf. on Coastal Engineering, Sydney, ASCE, p. 1528-1547. Kuelegan, G. H., 1951, "Water Level Fluctuations of Basins in Communication with Seas," Third Progress Report on Tidal Flow in Entrances, U.S. Beach Erosion Board. Kuhn, G. G. and F. P. Shepard, 1984, Sea Cliffs, Beaches and Coastal Valleys of San Diego County: Some Amazing Histories and Some Horrifying Implications.University of California Press, Berkeley and Los Angeles, California, 193 pp. Marine Advisors, 1961, "A Statistical Survey of Ocean Wave Characteristics in Southern California Waters," prepared for the U.S. Army Corps of Engineers, L. A. District, Technical Report. EN 14714, 30 pp. Masters, P. M., 1985, "Coastal Evolution and Marine Archaeology in Southern California," Oceanus, v. 28, n. 1, p. 27-34. Murray, W. A. and A. G. Collins, 1978, "Fluidization Applied to Sediment Transport - II," Lehigh University, Fritz Engineering Lab Report 710.2. Newitt, D. M., et al., 1955, "Hydraulic Conveying of Solids in Horizontal Pipes," Trans. Inst. Chem. Engin., v. 33, p. 93-110. George S. Nolte and Associates, 1983, "The Batiquitos Lagoon plan: a feasible solution to the restoration and enhancement of an important natural resource", prepared for Hunt Properties, Inc., Dallas, Texas, 13 pp. O'Brien, M. P., 1931, "Tidal prisms related to entrance areas," Civil Eng., v. 1, n. 8, pp. 738-739. O'Brien, M. P., 1980, "Comments on tidal entrances on sandy coasts," Proceedings, ASCE Coastal Engineering Conference, v. 3, p. 2504-2516. Papoulis, A.,, 1965, "Probability, Random Variables, and Stochastic Processes," Geological Soc. Amer..Bull., v. 72, n. 11, p. 1707-1712. Pawka, S., 1983, "Island shadows in wave directional spectra," Jour. Geophysical Res., v. 88, n. C4, p. 2579-2591. Richardson, T. W. and E. C. McNair, Jr., 1981, A Guide to the Planning and Hydraulic Design of Jet Pump Remedial Sand Bypassing Systems, U. S. Army Engineer Waterway Experiment Station, Instruction Report HL-81-1. Salazar, M. H., S. C. U'ren, and S. A. Steinert, 1980, "Sediment Bioassays for NAUSTA San Diego Dredging Project," Naval Ocean Systems Center. Technical Report #570, April 1980, 46 pp. University of San Diego, Environmental Studies Laboratory,1978, "Tidal As- pects of Batiquitos Lagoon 1850 to Present" prepared for County of San Diego. Weisman, R. N., A. G. Collins and J. M. Parks, 1980, "Stabilization of Tidal Inlet Channels by Fluidization," Proc. Conf. on World Dredging, WODCON IX, Vancouver, B. C. Woodward-Clyde Consultants, 1985, "Soil Test Boring Logs Grain Size Distribution Data Batiquitos Lagoon, Carlsbad, California," prepared for Sammis Properties, San Diego, CA. APPENDIX TABLES A 1 - A 13 NORTH SWELL SHOALED BREAKER HEIGHTS, ANGLES AND GROUP SPEED (From DNOD data, station # 5) Hoo = deep water wave height (meters) K = breaker height (feet) "^b = breaker angle (degrees) Cn = group speed (feet/sec) Table A-l INTRA-ISLAND DEEP WATER DIRECTION =245° Hb=ft. , °*> =deg. , Cn=ft./sec. T HQQ Hb 9.4 sec °<b Cn Hb 12.2 °U sec Cn Hb 17.0 o<b sec Cn O.lm 0.57 +1.95° 4.62 0.99 +2.02° 6.13 1.45 +3.51° 6.96 0.5m 2.58 +1.31° 9.65 2.94 1.30° 10.58 3.18 +2.81° 11.14 1.0m 4.70 +1.01° 12.98 5.13 +1.55° 14.05 5.34 +2.10° 14.39 1.5m 6.64 +0.68° 15.33 7.26 +1.65° 15.95 5.21 +3.51° 13.89 2.0m 8.55 +0.38° 17.15 9.14 1.51° 18.16 9.01 +2.65 18.42 2.5m .10.22 +0.001° 19.62 10.94 +1.18° 20.09 10.57 +3.07 20.08 3.0m 12 ,09 0.09° 20.55 12.74 +0.62° 21.59 12.00 3.33° 21.74 TABLE A-2 ZNTRA-ISIAND DEEP WATER DIRECTION =267° rn TT ^^ Hb 9.4 ^ sec Cn Hb 12.2 o<b sec Cn Hb 17.0 <*b sec Cn O.lm 0.94 3.33° 6.01 1.77 3.73° 8.25 0.70 3.77° 5.26 0.5m 3.31 3.57° 11.46 3.26 2.44° 10.94 3.01 0.34° 10.42 1.0m 5.82 4.7° 14.53 5.64 4.21° 14.50 5.89 0.37° 14.44 1.5m 8.10 5.92 16.86 6.94 2.91° 16.26 7.87 1.06° 17.15 2.0m 10.10 7.5° 19.50 8.88 2.99° 17.68 9.79 1.44° 19.02 2.5m 11.23 5.8° 19.81 10.38 2.98° 20.26 10.64 0.29° 20.16 3.0m 13.03 7.04° 21.58 12.15 2.94° 21.23 12.64 0.54° 21.35 TABLE A-3: INTRA-ISLAND DEEP WATER DIRECTION =277° rn TT Hb 9.4 °^b sec Cn Hb 12.2 <*b sec Cn Hb 17.0 <Xb sec Cn O.lm 0.99 2.22° 5.96 0.78 5.8° 5.31 0.81 4.76° 5.74 0.5m 3.23 2.02° 11.28 3.06 4.63° 10.74 3.86 4.71° 11.86 1.0m 5.17 5.47° 14.09 5.22 4.28° 14.40 7.07 2.12° 16.08 1.5m 7.18 6.49° 15.94 7.43 6.31° 16.76 9.75 2.57° 18.71 2.0m 8.87 7.92° 18.33 10.09 4.53° 19.67 11.79 2.84° 21.74 2.5m 9.14 8.19° 18.73 12.19 5.42° 21.14 13.96 2.85° 23.34 3.0m 12.57 8.76° 20.63 14.31 6,03° 22.13 15.95 2.75° 24.65 TABLE A-4 INTRA ISLAND DEEP WATER DIRECTION =287° O.lm 0.5m 1.0m 1.5m 2.0m 2.5m 3.0m Hb 0.64 3.98 6.84 9.60 12.00 14.33 16.22 9.4 <*,. 5.92° 7.43° 11.32° 13.25° 15.27° 16.58° 18.21° sec Cn 4.94 11.98 16.34 18.51 20.76 22.44 24.50 SOUTH SWELL SHOALED BREAKER HEIGHTS, ANGLES AND GROUP SPEED (from Marine Advisors data, station C) = deep water wave height Hb = breaker height (feet) °<-b = breaker angle (degrees) Cn = group speed (feet/sec) TABLE A-5 INTRA ISLAND ITOP WATER DIRECTION T 13 sec 15 sec 17 sec 19 sec HOO Hb *b Cn Hb *b Cn Hb *b Cn Hb ^ Cn 0.5ft. 0.94 -10.50° 5.87 1.19 -10.78° 6.76 1.49 -9.66° 7.38 2.77 -11.97° 10.40 1.5ft. 3.13 -12.91° 11.02 3.23 -11.19° 11.21 3.34 -7.19° 11.34 3.13 -8.22° 10.81 2.5ft. 4.83 -15.62° 13.43 4.02 -17.29° 12.66 5.07 -9.86° 13.93 4.49 -11.79° 12.99 3.5ft. 6.28 -15.14° 15.45 5.33 18.33° 13.86 6.74 -10.96° 15.62 5.73 -14.58° 15.05 TABLE A-6 INTHA ISLAND DEEP WATER DIFECTICN =202o T HOO Hb 13 <*b sec Cn Hb 15 ^b sec Cn Hb 17 ^ sec Cn Hb 19 tffe sec Cn 0.5ft. 1.06 -8.4° 6.24 0.88 -7.74 5.69 0.89 -7.82° 5.79 1.03 -6.99° 5.99 1.5ft. 3.51 -11.42° 11.52 3.56 -10.40° • 11.40 3.29 -6.80° 11.35 3.75 -7.96° 11.67 2.5ft, 5.36 -12.98° 13.86 4.42 -8.42° 12.61 5.40 -3.55° 14.58 5.41 -8.49° 14.23 3.5ft. 6.99 -14.56° 16.19 5.79 -9.43° 14.70 7.04 -3.77° 16.77 6.97 -8.73° 16.05 TABLE A-7 INTRA ISLAND DEEP WATER DIRECTION =225° T Hoo Hb 13 C*b sec Cn Hb 15 ^b sec Cn Hb 17 %,sec Cn Hb 19 «k sec Cn - 0.5ft. 0.92 -0.39° 6.01 1.07 -0.84° 6.35 1.01 +1.63° 6.09 1.36 +4.06° 6.94 1.5ft. 3.06 -5.41° 11.54 3.08 -3.74° 10.78 3.10 -5.86° 10.58 3.11 -1.28° 10.48 2.5ft. 4.09 -6.63° 12.12 3.73 -4.05° 11.57 4.53 -5.67° 12.86 4.57 -3.98° 12.75 3.5ft. 5.37 -6.41° 14.08 5.83 -6.06° 15.11 5.93 -5.61° 14.50 5.89 -5.53° 14.73 TABLE A-8 H7TRA ISLAND DEEP WATER DIRECTION =240° m TT Hb 9.5 <** sec Cn Hb 12.2 <*b sec Cn Hb 17.0 °^ Cn 0.5m 2.72 +2.06° 10.20 5.56 +0.23° 14.93 3.22 +0.80° 11.11 1.0m 4.73 +3.46° 13.55 9.54 +0.62° 18.56 5.69 +0.85° 14.31 1.5m 6.59 +3.63° 15.76 12.53 +0.63° . 21.98 7.77 +0.45° 17.20 2.0m 8.33 +3.67° 17.55 15.07 +0.56° 23.91 ' 9.86 +0.33° 18.90 2.5m 10.14 +3.80° 18.54 16.90 +0.75° 25.36 11.64 +0.25° 21.11 3.0m 11.04 +4.32° 19.93 18.46 +0.65° 26.40 13.35 +0.34° 23.00 SHOALING WAVES DUE TO LOCAL WIND GENERATION (from Marine Advisors data, station C) TABLE A-9 DEEP WRIER DIRECTION BAND; 304-326° T Hoo 0.5ft. 1.5ft. 2.5ft. 3.5ft. Hb 2.74 9 sec 3 b 19.61° sec Cn 9.31 Hb 5 4.01 4.57 Sec ^V> 21.07° 23.41° Cn 11.52 12.96 Hb 4.31 7 ^ 16.52° sec C* 12.13 TABIE A-10 DEEP WATER DIRECTICN BAND; 282-303' T 3 sec 5 sec 7 sec Hoo Hb Cn Hb Cn Hb «b Cn 0.5ft. 1.5ft. 2.5ft. 3.5ft. 3.06 23.59° 10.74 3.86 6.89 12.86° 19.13° 11.86° 15.77 7.32 18.38° 16.34 TABLE A-ll DEEP WATER DIRECTION BAND 259-28Oc T HOO Hb 3 sec *i Cn Hb 5 sec °^i> Cn Hb 7 sec <*v, Cn Hb 9 sec o^ Cn 1.5ft. 1.74 15.40 7.71 1.88 17.84° 8.47 2.48 10.82° 9.87 2.5ft. 2.83 13.96 10.32 4.16 20.68° 12.09 4.47 18.12° 12.5 3.5ft. 6.94 19.67° 14.88 5.43 20.66° 13.97 5.82 19.23° 14.60 TABLE A-12 DEEP WATER DIFECTICN BAND 237-258° T 3 sec 5 sec 7 sec 9 sec H.» Hb <*b Cn Hb Cn Hb Cn Hb Cn 1.5ft. 2.5ft. 3.5ft. 1.76 9.21° 8.24 1.80 3.53 11.61° 7.79° 8.34 11.40 2.25 4.99 11.49° 11.84° 9.17 13.45 6.19 7.01° 15.13 TABLE A-13 HFFP WATER DIRECTICN BAND 180°-225e rn TJ Hb 3 b sec Cn Hb c oa't,•J "0 sec Cn Hb 7 C^uo sec Cn Hb 9 ^sec Cn 1.5ft. 2.5ft. 3.5ft. 4.5ft. 1.93 14.38 ' 8.26 2.02 3.0 6.28 7.04 19.74 19.47 16.73 18.33 8.08 10.22 15.45 16.17 3.01 5.45 6.99 18.86 19.27 14.56 10.28 13.9 16.19 2.63 17.36 10.21