a - MO ow ot pe tere btn soe 0 eee Bean wet ol we aaa rete oes esata webote vavpenenste remem or yaigen semen ptt eee oe - ) in i : ' T 29e@TEOO TOEO O WMA A 1OHM/181N Ftd, THE OCEANOGRAPHY OF SANTA MONICA BAY, CALIFORNIA Volume II by Robert E, Stevenson, Richard B. Tibby and Donn S, Gorsline A Final Report submitted to the Hyperion Engineers, by the Geology Department, University of Southern California September 18, 1956 iF ; Y rere ei 8 | = ® oS * / : 7 10) YRS AsCIMAROO: BAT ~ oT ae ~ ‘ ATAROA LIA (AR. ADTAGM ATVAS \ vd * rédiT .& Bredsil ,eoansves< .1 tan Dus anife19D ,2 moo! pa0qgak fears ‘ ers6nkyes no lieayF eaf¢ oF hg f * Letra eirentasget yg¢las? ong | slototilesa? waetzne? to YPER avka O2Ct BE andwarged es For TABLE OF CONTENTS and LIST OF ILLUSTRATIONS See Volume I oe) wer: pai i [pee y. ee CO ee yen Re Le Vita \ r j ie ae ; : PN ; a enone 19t ‘ PTetTHod WAT Pte wus y AAT SRL, WW Tatd 4 4; * re) *4 3 * -~ 140 of 5° or more were required in the inshore area to retain the desired track, which were followed in a few minutes by similar corrections in the opposite direction. These fluctuations in the water motion were not due to tidal action, for the same corrections were necessary on subsequent traverse lines to remain on course. WATER SALINITY AND NUTRIENTS Methods Salinity determinations were made using the titration methods described by Knudsen (1901). Only one titration was made per sample, except in cases where the results were questionable. At intervals checks were made on randomly chosen samples. The resuits of some of these are shown in Table V. In addition, a series of repeat analyses were made to determine if variations existed due to the different types of bottles used for collection. These data are shown in Table VI. To minimize the changes due to storage, samples were stored in the same type of bottles aboard ship and analyzed immediately after each cruise. No salinity deter- minations were made aboard ship. Subsurface samples were collected from Nansen bottles except for some bacteriological stations where the water sample collected for bacteria determinations was later used for sali- nity analysis. This, of course, was necessary in order to eliminate the chance of sampling different parts of the variable nearshore diluted water. Surface samples were collected with a large rubber bucket. , » : \ " Ra bee wht <4 ¥ Pad : rir ty | ee i : si@atetes QF sane ot vdzok off° @E er tepe+ seae i ad 4 itinte od abaecke «cl » QP Poh? easy erie aoest ? 9 b ue 7 7 visi tgedanl” c* dation 1th, SPiaaqo 1. OA : . i * - ; ube oes? ee AR Lee. Se eee aa ee eo ee 4 edt! eryave Creevessa oia8 ¢ (y > J 5, * - = STMATTVe (BAN YRMETAS Nae siwdtsl ’ wei ei+ at? Qakaw ciew saQetlehotton) costeb Qaae Bnw: aor Feist wae viet FeLi as eit ji G beds 2 one Ne syow etioees sf+ svetwaaagi- al ' (cone sete -Wieotos? no obaa 4% eX oets 2iny¥ “4 Sh ae le , ee xa 90682 oO Shon $6 -e2ir» : mtr » Seba e x Sing: stow cesyiaae 4+pndes i | RBERe « ans FE Sty el! sur? S$apistzib eff of sb Dates Br ‘tol 3eveRe 30 a ei awode ozs efeb sacdt “BObRtS°t Loo RR REee eee esiduan .wgaxots.67 ocd gogekek> vs ssiegein-wt OF te Gide trsede avlited to ogy) siiae oft af be seteth vtinilee oM ceekeee ver aot elataltogak be qits tintde, Stew 220s tod ven aont Betee ica s1ew Epigaae oes rn atomes tstew 4%) suse adebtare tooigohehaseoee eee kien 16% toon sotael eae ins tsciars? ere aed: 307, ) vetee ai ¥edeeesse gee .eereep ae Ahet 7 ainylona 4 avi ) e5gaq Nee tes gnkiqnea lo vine et ven teree Dek ids .tetand aoedtp? onret » pti baiagh 7? wa be é 141 TABLE V SAMPLE TITRATIONS INDICATING PRECISION OF OPERATOR Sample Number | Duplicate Titeations | Average C1™ 1014, 3/28/56 | 18.61 | 18.60 | 18.61 18.61 1104, 3/28/56 18.60 18.60 18.61 18.60 meee,ss/23/56 «YY 18.60 ¢2 ce 18.59 | 1316, 3/28/56 | 18.62 18,62 18.62 18.62 1342, 3/28/56 | 18.61 i | 18.61 18.61 | 18.61 y wy - 7 . - row _ ” Ahi he ae f Lbt V S.1aaT im - et wi ey Greene = AQTASIO 40 iO) 1210684 mnrteo gaunt avorrasT TT é Se ae rere ae eee ae ne Sa teeter oe (aaa — = ; vr aL “£9 agaxevA enoktess iT staobiqutl | La - en ee FG A TN I EE I Sa Re A 7 ne anes eee la ot Z . 18,81 04 BL “ DSLBL $0.85 $8.84 wa Soler 1d.8f 19,84 | A ! y ’ — , 7 al irr j a Wh ” =a « f f i 3 ig f 7 ‘ i Dh | h _. ; Saree oa * | er a ee 7 142 TABLE VI a COMPARISON OF BOTTLES USED FOR WATER SAMPLES Station Number Bottle Type | Initial Final | Chlorinity | Chlorinity H i 4217-56 A | 17634 | 17.49 B let 1RbaS 17.35 Cc 17,36 17.41 ——— ——————— ae A | 4218-56 A lc LAGOS 18,07 B 17.96 18.00 | Cc 17.95 17.96 scans 5S 2 } — | se ete ad _ + 2S a See 4219-56 | A | 18,24 18,34 | B 18.24 18.23 | Cc 18.24 18.23 4220-56 SK A 17.77 17.89 | B 17.77 17.78 S | 17.76 | 17276 4221-56 os A 18.48 | 18.56 B 18,48 18.48 c 18,49 18.49 4224-56 be 18,42 | 18.56 B i iwyey43 18.43 c | 48.43 18.42 The initial chlorinity was determined within four days after collection, The final chlorinity was titrated three and one-half months after collection. Polyethylene bottle A was capped with an ordinary plastic screw cap. The citrate bottle B was standard with a glass cap and a rubber ring seal. Polyethylene bottle C was capped with a plastic-cone-seal screw top. This latter type of seal was the standard used on this survey. | he Wh 7 ae } \ Ww i) Vite . \ ,« bas " tb ee ' re Se a a ‘ -. Vee 7 rv agar Be i ate - _ + eee ot ea “so Sintec — - aa : connie RT ot omen gr3O HO — a0) fenk4 tee dev? atftetl 29cm y2inzrolio ee a | eat L | | bE NE A RET RETE ai ra.o | ac, Th | e 0.82 ) COL TEN A 10,82 oe,T£ . 5 49.7 | RON + A is porate $6.82.) AS 85 €s.&s ' bS Sl ; ES,82 of aa J €6,VE / Tru tz ) f SVT! / TT els oy, ti rea | | ac Sf ‘oe A,Bl A SRL OS rare | a Ch at i 52,8! S332 A £b,et ) ch,8L | a Sh. Bs Ch sr | | 2 evabd igo? sbitiw bonimsetsl eew «tinksefdo 16b8R ‘Devestl? sew Ye tarwelap Leni? eV 2tOSLies srstie ad:com Yigt-oné Sitasiq. yrsadhse we ad bew Hoediss aaw ‘ “AT §6omvkioS A alrtod a rf & bis quo ‘avety, F Aoew brabhusia exw'h eltted ret Leow erent % @iiw bogged 2aw) 2 elites tahoe te eed taw inde to sqyt 5 «F498 = ie et) aR Tad if om nh 7 ah i Cis 143 Equipment The Nansen bottles were used, as noted previously, for obtaining subsurface samples. Reversing thermometers were placed on each bottle in order that the temperature and density of the water sampled at particular levels could be determined. The water samples collected during the bacteria studies were obtained with a slightly modified Zobell Bacteria Sampler. Additional Sources of Salinity Data Personnel of the Los Angeles City Bureau of Sanitation, directed by C. G. Gunnerson, have collected numerous water samples in Santa Monica Bay during the past two to three years. Chlorinities were determined by silver nitrate titration, but a potentiometric end-point was used. The chlorinities obtained for identical water samples by both Hyperion and Hancock Foundation show that the values differed by about 0.06 o/oo, or about 0.11% in salinity (Table VII). This is a rather large difference, and in any future work the two methods should be more carefully compared and the source of error eliminated. Some salinity data gathered by the Scripps Institution of Oceanography were examined, but their stations lay beyond the area of investigation in almost all cases. Salinity Data for Shelf Water Vertical Variation The vertical chlorinity variation in the bay as a whole is shown in Figure 72, in which the chlorinity is plotted against depth for the shelf water down to 300 feet. wenivaag boted sis Ubhae Seow apiaroe foe 4 Lpe Steen 77) BRPaRre 4? As ,#eige@at 7 2 bo Gee ¥ , i Lol teh Sis : eis Los aval 39 p74eq te hel4aaee TO% a2 7 3° :¢ ont Oe tieo Ppalcase wh Pas ee wil od i i leth vi ; a ne iG ‘> 2445087) ‘io Llecage mee “ye (fa rin & °.8o . ; A | od rid ¢a TES) | 72% psgz aee7et enh btarrods ys j ep as & @k2a7 Se rox @ 2a ek 3 aat sis ide 2els ee weds Jmonse Ge al : ‘ ' ai &Li.Y +) eee 60 @ [087 ' o7ect yediaz bi tapteels ' nT hd a te eh &2eo rsiakige be tigta Iieed ov oA Leap eaew, Yaqs se ensued Ja} ne at cokianitasra@k te 7H etsy R , sate : orntFot aay 1 token 29 taokrsee | a" ttate of weenleeitp oat sate mi i) eg = ? ue » “ - ¥ ym 1G | on i » ioe) OUE, 63 ati, anita. Be ae + : 144 TABLE VII COMPARISON OF CHLORINITY TITRATIONS BY AHF AND HYPERION TECHNICIANS AHF Method- Knudsen titration with colorimetric end point. Hyperion Method- Knudsen titration with potentiometric end point. Station Number. Depth 0 Se ee, ee aL ET¥ AJGAT. cag i oc eee me ee Ya porte YTIM DOIN 40 woe tanioo UIVHORT WOLAIIYH GMA SHA = ~ Sp anigaageeateteeas enema = a ee te ae ee etuniog bas skatemizotes anil toitssdt? osebuok -boagy >ixtomokinetog dtiw mokjeatts asabpad «bodtoM .tatog” Bre SEGUE Mamie arm) . nogreq yi | f } nu “——— po (eh C&.BE 7; ¢& Op Br | he sGZ Sb. 8! he BL os.8! £2.82: 145 Figure 72. Vertical salinity distribution in Santa Monica Bay, 1955-56 (= uJ uJ ie Fa, x= KE a uJ a) o fe) 1D) (o) (e) CHLORINITY IN %o (eo) SEWAGE DILUTION AND EVAPORATION ZONE NORMAL_ SHELF WATER SHELF BREAK AND SLOPE G fw ba o , J 1G J0AW Re Qua vO’ VOTTAROFAYS mest + omeewlint 1132 _JAMAOW Afirhly OT AW pre eating on ee eof Vi YT) +p Wi Gi 8 ie oh ] a afk i AGJHO 146 It is obvious from the diagram that the salinity (chlori- nity) of the shelf water is essentially uniform from a depth of 40 feet down to the approximate break in slope at the outer edge of the shelf. The median value of 33.50 o/oc €1=18.55 o/oo) has been used in all computations of dilution as the value of normal shelf water. Above a depth of 40 feet, the salinity varies over a considerable range. This variation is due to two factors. First, the effect of dilution of the normal shelf water by effluent; and second, reduction in the salinity of the surface layer by natural runoff and precipitation, and increases in salinity due to evaporation. It is obvious from an examination of the curve in Figure 73 that the highest surface salinities are still close to 33.50 o/foo (18.55 o/oo), indicating that dilution and replacement by currents rather than evaporation is the dominant factor maintaining salinities in the bay. The overlap of points taken from samples obtained at dif- ferent times of the year indicates that there is practically no seasonal variation taking place in the shelf water due to dilution or evaporation. This probably means that the water of the bay under natural conditions is entering and leaving under steady state conditions. There is no marked variation in salinity at any depth over the shelf, showing that there are no locations where water stays in place long enough to be appre- ciably changed by natural or man-made factors from its entering State. The uniformity of the salinity value of shelf water off the southern California coast is further shown by the identical median values for shelf water obtained off Whites Point and Orange County Uuring the survey period. It would appear that 7 Terra. i vias Fir i. iy De eee Peas, oy) GE' ORD re ery, «2e@in) (ohh edt tat) Od 194k ae neo tee at U bs meat ere 1 lite Tilei tase a2. ory ae + Lear «ft 765 J ‘ i" ‘> Peim | MA aveagei: of Baw wT per x9 3eGe “A? of een Oe V0) € OL cn BBA | i Se ale on! (Lo oe liet off o ayiaw eat we wot PEER We maphiptaqms isa a ae VILetin ¢> steel OF ea aigebe Gs sofaw bles out ot out wi wottetuiy e8at payee éapitves & x4 ssfaw 7ione aid hs. To nok teeta 10 tu od Seen “da 2x2 ' Lo fintine @fd ob Babel bao oot Bie OF ' ai 2eeeei7n Hite , nol Spl iquaoeed> G: ws te‘euT og - | gok? attics t ‘ wikwdo. BE Bhat is¥® of. Sos a ii : (4 Patias : 1 a taea- eat edt: mit et 6 : : rad ; ( d SL) ae { 4 saole Ss aA ,} ay . 2h aetiared * man «ez ajeeraes, ye ? oelges 28 ’ } gt Od Re r7hatipea gran Lew Torde? See | i %6b te heckatao evlaner ova) 62447 qj oa Czeeve ' efliesziGatG 2 reds td? eat gars ay safle see . ; roisaw Visa® Sar. Ba eigiq firs x- 00a ceer Lawed | F 47 tedt eaada vi dado? nna! ‘teewoekve 26 iY a fh i vet tod eahbeethe ef WHOL) 2 IC™ (etedaem wale ved } ‘ F dven of wi ied yep | +i bee, ete7n ‘ey ir bw ssa: i ety siged Yau Te wT 4 a ., f a : ~ oe “ of eee Ben aealg » ‘vale feta soe esta a aft } oe? gyetan) gine 00 10 ARR Te testi 4 ' ble er: oye pe Sages De iy Oe Pisorise ott mad rel dewneein: ayuely Gs are) sinaolites na » setod wotide Vie dewie te 1a Wade As hn saeqqe Moow tA eetiails hee one pas auf, ia wars ; i. Fig’ 4 are 147 Figure 73. Cumulative percentage of chlorinities, Santa Monica Bay, 1955-56 0 o = oe = e a O a ce O Oo O © Vv LN3ADY4d AAILV INWND D 9 a e > - > = % ; a ase 148 the shelf water is a well-mixed mass having its origins out- side of the area of investigation and remaining essentially uniform along much of the southern coast due to the absence of large rivers or streams which, if present, would tend to Cause a progressive dilution. The only variations are restricted to surface changes due to evaporation and dilution. Dilution from Salinity Data The principal area of diluted sea water in Santa Monica Bay surrounds the terminus of the Hyperion outfall. This field is the result of the mechanical diffusion of effluent into normal shelf water at depths of 40 to 60 feet at the outfall terminus, and subsequent eddy diffusion. Secondary areas of dilution occur at the mouth of Ballona Creek and at the mouths of the various creeks draining the Santa Monica Mountains during the rainy months. The water discharged from the Edison plant is shelf water and no noticeable change in salinity results. These latter areas are of little importance. The zone that is recognizably diluted is almost always confined to the upper 10 to 20 feet of the water in the bay. It normally ranges in salinity from 31.80 0/oo to 33.42 o/oo, as is shown in Figure 72. The Effect of Diffusers on Dilution It has been observed during the course of the survey that effluent tends to form a column which mainly rises to, or close to, the surface. In shallow water, as at the Hyperion and Orange County outfalis, the individual ports (Hyperion) or the terminal port produces a rising turbulent column containing . —2 ‘i : i ; ro iaigaaoress yoives peat Sexnie- flew’ a at rehee TF th ci'epeee Brinicwan beta morgaginzervot: 1 4226 Sat s7eoeds “atte 09 2090) Pieter e7f lo ‘Son BRE ot based blwew.,icece rd RR Gokew amerets 72° eee ieet) orm onottela:* _ ees wifulth opisebanon olioiib bee SBERetegers. 03 275 4pgeaRS > ( hint ia abs? &e! vet af s8taw Ste Bagel? : Iegionizg ®t bo Sita ‘ exul i was ~tl af ; aA? S¢ it 3 *¢ 7 eae, .< % i 2 ite) to sah 1 Tisieere bea tit? yey orege bas ers iow 3 5 bee : gto ELAN Ve ; F iu? Ta 2no08 oAtadb autetored ablne/t ATMA BAe gcin woot. aorta , ey ii ny ee Pe ee 2a700m s+Seg ah AGeel® Sides n: ‘ ew fetew nuopeqnel at? + et ee, gw! wunke BE Beane dae o4x ) / Datly Cara a eat Ot ? 5; ow i? .% $95 i “Sia “42 29 & RS Bio Wa = key h) ; na pk 25a 1 a qos ol me mer 1) S2SeP 7 520 5. i) 207% ' OES) St . om a] ~ tou, ot eeely Tit Bakde son !op eGR pr Conds ae = a Gu Tipges yea 1<¢ wh ve Ee bee ipa Py 4 tet wy! ipas ax \ aaa aie ed J ep > 7 7 eS / 7 va (notisqyh> wires MWR RReh tek 342. pe eee sees. sj T ay a ah yi, anen wares tape see entars & revi eed Fae F 4 ‘ Pe ie il n wiser! y= Sy y 149 fragments of water of widely differing composition. This requires that several samples be taken simultaneously in order to compute an average dilution. It has also been noted that the dilution initially produced within the column or within subsidiary columns, is similar for virtually all outfalls examined. The average dilutions range from 15 to 30 parts of sea water to one part effluent. In deeper water there are indications (Whites Point) that a slightly higher initial dilution is achieved, probably because of the greater length of the turbulent column (50 parts of sea water to one part effluent). The dilutions were computed using the following formula: x = 100(Smw-Seff) . parts sea water in (33.5-Seff) 100 parts mixed water Dilution = X 1L00-X where X is the parts sea water per 100 parts mixed water Smw is the salinity of the mixed water Seff is the salinity of the undiluted effluent 33.5 is the salinity of normal shelf water in parts per thousand Dilution is the parts sea water to one part effluent The effluent salinity (chlorinity) can be measured at the shore end of the outfall, the mixed water salinity (chlorinity) can be measured by sampling the sewage field, and the value for normal sea water can be obtained by statistical analyses of many Salinity determinations of bay water at various depths and seasons. The resulting equation is useful for computing dilutions of as much as 200 to one, depending on the errors in * * if ) a i ur sas sow (eSi Tine ips! pet otiy 4 a awe eT tao cde PuAd 29%, ‘) ol rinae gf S').: vo He O2ae as POE af 110 £2 a ; j Me Loo a: aa » ad Yi re pie Tat | igaAa ‘ns tnd 1 Panic Hote LZR 7 i> ee it Mm A, - x Oi j EE =? 6 Mee 2 PeeIG - 7 140 Ges)? Tra) eA tn Tivo edd 46 . upe vd heQRe =F a 4 ; pe v1 par gue! nites haat eh 9 282, rt ~ ns ae erntsces ade ie ny er *\ - x ae ot Set oe Com, edt - baer) 150 determining the salinities and in choosing a value for the salinity of normal shelf water. Extent of the Sewage Field Figures 74 and 75 are typical representations of the sewage field, as shown by surface salinities. On both charts limits are defined by a salinity of 34.40 o/oo, representing a dilution of one part sewage to 332 parts of normal shelf water. On June 20 and August 10, 1955, the sewage field was better defined by salinity than by temperature. On June 20, the field was restricted to an area extending between Playa del Rey and Manhattan Beach and approximately 23 miles from shore. On August 10, the effects of a northerly flow are evident, with the field occupying an area between Santa Monica and Manhattan Beach and 3} miles from shore. Minimum sali- nities were encountered at the outfali, and were less than approximately 32.60 o/oo and 32.90 o/oo, respectively. Nutrients On January 13, 1956, and on subsequent cruises the central and northern parts of the bay were not covered, but on that date and at a point about 15 miles off Palos Verdes Point the concentrations of silicate-silicon and phosphate-phosphorus were approximately half that present on August 16 and 17, 1955, and they showed a slight increase with depth. Nitrate-nitrogen at this time could not be detected in the surface water, but it did occur at deeper levels (2.0 pg-at/L). Only a trace of ammonia was found in the surface water, and oxygen was near saturation. i hae mE yl) ] Bi aaa Sa Toe r / te a ee ey ee eet eee | fie hee Lions f er) oon? ii ia wi Nt, be adit yer » ba +9 gookiagn it'S2 hi & “ > due th 3 en ee UCTS 4 f ey Yarlit & ree 4 zat) ee oe 1 aw , omar oR | ae Bees; / it: no me. ‘ef tps ‘ : : r ‘ i go ee Tt ee 35 “2 z cer rie Mating: ARS « goats: TS esas a ? A H7o4 Baei gy c wh err. J = i {AS ats . a4 4 Ge KI PERSP thea cprddpe a 2 rs vannle oi veow Ys : oak At ‘pied & Meat + Yee vealin 2 te tntow « 1a fs cle b ealeys dq ore pet nv Se Sogn 7 a Caan aig “ea at fae Pac ; fs wilt At: Wernsin uy id bhai at Pitan Od! hayes vga 7 wea Es be Sy SMC a AE 4 ont enn 1's pier 4 151 Figure 74, Surface salinity, June 20, 1955 Va OR ae eT STIUH S30N3A SO Wd HoOv3e OONOG3Y HOV38 WSOWY3H HOVW3G NVLLIVHNYN ——— SS Oanno3s 73. ee AaYu 130 VAVId ssél ‘oz 3nnr ry SOINZSA idd NI S3ILINIVS + ALINITVS dovauns VOINOW VLNVS SS —_— — —— —_— 1334 NI SYNOLNOD WOLLOS S270IN 34inNivis ——_ —_—_-——— ese » & » be | 5 c 26 ; , oes iy be mw 152 Figure 75. Surface salinity, August 10, 1955 i. a =i | “Ty T Nels ws! a \ \ %, ° 0,°8. ° On STH S30N3A SO 1WWd) ( SO l / HOv3e ° OaQNOoG3uy HOV3@ VSONY3H 1\ e et HOV38 NVLIVHNYN ABABA BABARAT “$s OQGNNS3S 13 AaY¥u 130 VAV 1d L sséi ol LSNONv SSINGA ‘dd NI ALINIIWS + | ALINI'IVS HOVAANS r VOINOW WLNWS Ve: ° 1334 NI SYNOLNOD WOLLOG L S37IN_-31nivis € 2 ' ° | WE VYIINON VYWINYS SE Ov SY ( its (Basta ’ ~ ; > 7 Sal Pprwisan OMteUE. = os 153 A detailed survey in the area of Redondo Canyon on June 7 and 8, 1956, gave surface values of 0.3 pg-a/L of phosphate- phosphorus and 4,0 pe-a/L of silicate-silicon offshore. These values increased toward shore to maxima 0.5 and 6.0 pg-a/L, respectively. An attempt was made to determine ammonia, but the method was not sensitive enough to detect the small amounts present in offshore water (0 to 0.5 pema/L ). On the north side of the head of Redondo Canyon measurable amounts (between 0.5 and 1.0 psna/L ) began to appear. Phosphate, silicate, and oxygen values in the surface water were considerably higher than on the previous cruise in January. Throughout the area no oxygen values below 95% saturation were found, and a number of stations indicated a supersaturation of up to 7%. Conditions at the Hyperion Outfall In the vicinity of the Hyperion outfall the nutrient salts were concentrated considerably over the values found in sur- rounding shelf waters. A detailed traverse parallel to the coast was made both north and south of the boil on January 12 and 13, 1956. The dispersai pattern of the nutrients in the effluent was found to be different than at either Orange County or Whites Point. It is believed that this difference is associated with differences in oceanographic conditions and with differences in the character of the effluents. The higher concentrations of nitrate and silicate and, to a degree, phos- phate were found in the subsurface and bottom layers with an | intermediate layer of lower concentration at a depth of 20 feet. On the other hand, ammonia-nitrogen decreased from a relatively high value in surface water to a depth of 15 feet, where it he id ivrees Be , : -of¥stes @ = p 7 . 1 ' ioe e io A ge Brag es RR ++ =k - ‘ i * Bas + | (sz spree REE ts s ip 2acdspusas ad : : : a 0 7 soe 154 approached the value found in shelf water generally. South of the boil, although there was a decrease in concentration due to dilution, minor maxima occurred at 6,000 and 9,000 feet. The maximum values recorded within 3,000 feet of the boil are 23 pg-a/L for silicate-silicon, 10 pg-a/L for phosphate- phosphorus, 6.5 pg~a/L for nitrate-nitrogen, and 68 ps-a/L for ammonia-nitrogen. In comparison with the Orange County and Whites Point outfalls, Hyperion had the highest ammonia value, the lowest nitrate value, with intermediate phosphate and silicate concentrations. The oxygen concentration of the surface water was low in the boil, but to the north and the south it approached saturation within a few thousand feet. On both days large tongues of supersaturated water (up to a maximum value of 33% above the saturated value) were found in the intermediate depths and at the surface. The large increase in oxygen content above saturation values is normally attri- buted to phytoplankton; however, vertical net hauls in the surrounding area showed low plankton counts. With the exception of one or two pockets of low oxygen at intermediate depth (ranging from approximately 40 to 50% of the saturated value) the area, with the exception of the boil, appears to be well oxygenated. Generally, the average oxygen values at Hyperion are higher than those of Orange County or Whites Point. An average value of 5.02 m1/L for both days was found in the surface waters of the boil, implying that there | is an adequate amount of oxygen to meet the present oxidation requirements of the effluent. i ‘ o a) : # .« stisediing anedel Homey beast staan coe an bs > 4 087% 4 ae 4».15 ss Ran | wotktie - oi : tj ers ee tat*, bis ? 7 yim volta 7 fete i acm 9 ~“saiav Sng , tf Lor esbifze aot? Ze ee} if ino @eO-a alagiyeg ma a 12 > eowvse BOSE iogao 347. a58 ' noo 2 iat) aivob ioe - ! +4 4 ‘o,a ve bots we 52 . - “ i iow og ot a » ddeath’ ses i ate Mebroqr Gace oS Kin £0.24 ' ‘he im ‘a9. yoko 4 - ) ’ —p hom 1s mE LP bOd wel + «ap? te pha'tees oad wah ’ | ’ ze. Peano yy Coty FE “nee wham sha | \ a -¥ on ts ie bee bt | eter cory a r ia oe - 155 Radioactive isotopes were used on the cruise on May 22, 1956, to trace the dispersion of sewage in the immediate vicinity of the Hyperion outfall. Previous to this, direct information on dilution factors around the outfall with which to compare the nutrient salts had not been available. Twenty curies of scandium 46 were injected in the sewage and on its appearance in the boil, the radioactive count was picked up by a scintillator probe over the stern of the VELERO IV and followed for the next 24 hours. At the time vertical profiles of the radioactivity were made, phosphate and ammonia deter- minations were also made. The limit of measurable dilution of the scandium 46 in the sewage field was 1 to 10,000. Sur- face samples of the station occupied in the boil on the first appearance of radioactivity gave the highest values yet found, in the area of 11.6 pe-a/L for phosphate-phosphorus and 112 ps-aL for ammonia-nitrogen. The ammonia-nitrogen concentration is the highest recorded at any of the outfalls. The approxi- mate dilution of the scandium at this time was 40. At a depth of 45 feet, the dilution was not measurable and the phosphate and ammonia had decreased rapidly to 0.8 ps-4/L and 4 ps-a/L, respectively. In tracking the radioactive field, the concentrations of ammonia and phosphate did not decrease in the proportions indicated by dilutions derived from the radioactivity. This can be partly explained on the basis that the radioactive field was being mixed with water from the surrounding area, which it- self contained variabie and unknown quantities of nutrients. Therefore, the time rate of change in ammonia and phosphate could Fl not be determined from the radioactive experiment. Pais ) eae : om | ; tS ly, \, 2p 156 TRANSPARENCY Methods The transparency of the water in Santa Monica Bay was measured using both the Secchi disc and a hydrophotometer. The Secchi disc, a white metal plate 30 cm in diameter, was lowered at all hydrographic stations as a standard procedure. In 1955 and the early months of 1956, no particular concern was expressed about the transparency of the water in the bay, so that no attempt was made to determine any Seasonal trends which may have existed, Aithough numerous readings had been obtained during the summer of 1955, the meaSurements taken throughout the remainder of 1955 and 1956 were scattered, and the density of the stations was mot enough to allow the com- pilation of seasonal charts. Newertheless, determinations of transparency in the bay taken throughout the year were in sufficient numbers to compile a composite chart of the average depth to which a Secchi disc can be seen (Fig. 76). In spite of the antiquity of the instruement and method, definite expectable patterns are apparent that show the normal offshore water conditions as well as the influence of sewage discharge. The hydrophotometer was loaned to the Hancock Foundation by the U. S. Navy Electronics Laboratory, San Diego. It consists of a metal frame holding a light source and a receiving prism-photocell, one meter apart. The light reaching the photocell is transmitted through a waterproof cable to the deck where the electrical impulse is read in micro-amperes. In the first few feet of water light not only came from. the i] o , ~ : : ; ; , . ss a f { , ny yt 157 Figure 76. Average transparency of Santa Monica Bay, June 1955 to August 1956, based on Secchi disc. Os ¢ Ss Ve HOv3¢e OQNOoG3ay ¥ HOV38 VWSONY3H HOV38 NVLLIVHNYN OGNNS3S 13 L334NI SYNOLNOD ADNIAYVdISNVEL \ AIN3SYVIDSNVYL JOVYEIAV SYNOLNOD WOLLOP S31IN__ 3inivis e 2 | i?) ' We YIINON VWLNYS se 1334 Ni XESII K X 9S6! 1SNONW -Ssel 3NAr DS OF: OS {SS SE Ov ve : i _ +: a - ; 5 ' ? t ; . 4 _ | ; * ' ; \ HAIP MAG T T iA | y > D a Pal oer 04 . rao u2e5eh WAT TAKAAY ' Fi f if ; } ot Sage AeOMASH f j 'F. ; Tg30¢ 3% a a94340 : : ¥DWIAAAZUART JOARSVA Le eee: T2EUDUA~ ELC! SMOL i. Pe 158 electric bulb, but also from ambient light from the sun. The resultant of these two was computed against the standard calibration inti and presented as percentage of light transmission, The hydrophotometer was used primarily in water surrounding sewer outfalls to detect layers of debris-ladden water. Several lowerings of the device were made in Santa Monica Bay well away from the outfall, but no detailed pattern of stations was occupied (Fig. 77). Around the sewer outfalls, hydrophotometer casts were made at each bacteriological station and from the determinations of light transmission, many valuable profile patterns were produced. In Figure 78, for example, the surface portion of the sewage field can easily be recognized, as can the subsurface debris layer. In several instances the trans- parency profiles followed closely those plotted from bacteria Samples and they were, therefore, helpful in reaching the con- clusion that sedimentation of bacteria in the sea is an impor- tant factor in their disappearance, Transparency in Santa Monica Bay The average transparency of the water in Santa Monica Bay as measured by the Secchi disc is shown in Figure 76.. The waters within two miles of shore usually have a transparency of less than 20 feet and in the vicinity of outfalls or streams discharging detrital material into the bay, the readings are normally less than 10 feet. In deeper water and farther from shore, the transparency increases to a maximum of about 45 feet. Here the waters originate offshore and have little + “ ; ; 3 } 2aet Lae b “i It ® wa ’ -4 ia suwores ood 4 OTs, te i. ea ‘7 ' . q if : ' + et testi 2 r 8 7 a +> “ « sifes 3 . r>at > 1% “¢ ‘ rae rf Lae ~~ : ‘ . ’ j “i 4 - ‘ ‘ Me a ; 7 Low Lest r Dit & iF 7 s { cz : : ro} oe a 7 : '¢ ! ae f ‘ . - sat 7 ‘ ae? > 2 ait? » Pat Oe r i, t 7 « ; rane jyagnnat® Wass 159 Figure 77. Per cent light transmitted at depth of five feet for winter months (1955-56). FP Lai ere i) i] T vy? i ‘' ‘ es s to. fitast 7H Det? nensit tity it in ec tik Ai sotniw 40% 992 avis HOv36e OONOG3Y HOV38 WSOWY3H + | HOV38 NVLIVHNYW OGNNS3S 13 ve 13343 NI SYNOLNOD WOLLOd S37IN 3inivis ° ' fe 2 i We VYIINON VLNVS Se —— 05 pa ce “SHINOW YSLNIM Os Viva Hueaa4 “faa 6 ly dd THWSNVYL LHOIT LN3DY3d ee ‘ - \ \ / ) / / Bee / (Gea aes Sons ae iy eae a 48s = x \ Woke fe ee ee See ooe— ve (he = fee OL id ee ae "| ewen Kole] SE ord SY of “35436 A2CMREN } ns ek - a) e FIMeVART fe 160 Figure 78. North-south profiles of light transmission at Orange County sewer outfall, 7000 feet offshore, December 19 and 20, 1955, VW1WW4LNO YSaMSS ALNNOD AON VHO og <| | 08-02 WW Hie 3G. Z nm m m + NOISSINSNVUL LHI) INJD8iad- . 1 SJO00€ 0002 AaVsaENO F WO00c 3 > oss = sit = inte a 000! ne See er? es ee 0 ees abe, May trie) tte r 161 detrital material from the land to contribute to the turbidity. There are occasions, however, when plankton or other algal blooms in the offshore area increase the turbidity to the extent that the transparency may drop to less than 20 feet. This is a normal occurrence in all coastal waters along southern California. One notes from this chart that in areas well removed from any point of sewage discharge the trans- parency nearshore is much lower than that offshore. This is completely normal, for along any shore bordered by a low coastal plain or by hills or mountains composed of soft shales and sandstones, as are the Palos Verdes Hills and the Santa Monica mountains, the nearshore waters are turbid to a certain extent due to silt and clay contributed by streams and kept in suspension by wave action. Thus, the direct contribution by sewage to the turbidity of the water is confined to a relatively small area in the immediate vicinity of the outfall site. Santa Monica Bay, then, has waters that are naturally more turbid than those along the Laguna coast to the south or around Catalina Island, because of the geology of the adjacent hinterland and the nature of the circulation. Where- as along these latter shores a Secchi disc reading of 60 to 70 feet is not uncommon within a mile of shore, or closer, such transparencies have never been observed within 12 miles of shore in Santa Monica Bay. Any additional contribution of detrital or organic material into these inshore waters will, therefore, decrease the transparency to an even greater extent. ‘ wk e ; if4 49 mfudisiea : f natt ocd faieovem Bag vowel , Oe £Be990 Bae ee - + uy - ~ ~ i , ‘A er is Cas a” 4 ee LaF al ine Ceo & bog of she ha , 5 t ; C ¢ tractifaa al éva- ‘i enpw 3 cou wort BS faite %eGt ‘ * «i o7oneraa@ i‘ ‘4 ber4bae 6eodn * lamio8 ri r o tembqeey eelke den ys oh ea iee ’ a = = ‘1 ; I 29ce te + ~— _ a0 cey Gee sia » % wit bw 3 . fia oF Se tie : ong! a ‘cw 7S Beem oe 1? oft of @ ao a © tilawgea vison ‘ 7 255 20 é ; f 1 wet? aclo i Leia us si selzetnia bass cu oon retta? o¢sdt. a geade Aq ide o° a2 i guodes 16h SPR a are , byvre ede. Gerad wy = "aa 2°) OMS Ta Gaml i ’ amsrtinne a) ofl «sivas a?aee ab ov ‘een? oTae (elIIvtS n Jee ga? re AS i _ ay hae) gs 7ftaye ae ady 28R020Dd 98 | Fi 7 = ue : t 162 Compliance with State Standards On May 2, 1956, the State Water Pollution Control Board established transparency standards for Santa Monica Bay which are to be conformed to “insofar as such conditions are affected by the waste discharges from Hyperion". The conditions, as stated are that, "The transparency at each sampling station (B and C), as measured by the Secchi disc, shall equal or exceed 20 feet in 50% of all readings and shall exceed 15 feet in 80% of any 20 consecutive readings.” It is apparent that at the C stations in the nearshore part of the bay, this requirement cannot be met at the present time. It is also apparent that a transparency of 15-20 feet may not be met at specific times at the other C stations, nor at the B stations. This second condition, however, is not likely to be prolonged over periods great enough to constitute 50% of consecutive weekly readings. The question then arises as to whether the turbidity in the nearshore waters can be attributed to the present discharge of sewage. Analyses of the data gathered during the bacteriological work to determine the extent of the sewage field indicates that for distances greater than two miles from the outfall, the presence of sewage is undetectable from particulate material and detectable to less than 1% from chemical data. It is reasonable to assume, therefore, that turbidity resulting from the addition of particles by the sewage extends for only two, or slightly more, miles from the outfall. The low transparency of the water along the shores of the rest of Santa Monica Bay must, then, be caused by natural conditions. os + eo Te? nisy ay oft , 2.72 eee cf is nijaaw ron ttkw awoke offi it . y - a wt. an | aQe? «4 ia bie * oe ‘we 2) m - nesanasdg Laseta A oe © . 7 Aor od 164 The Relative Merits of Transparency Instruments The antiquity, simplicity, and obvious inherent errors in the use of the Secchi disc for the determination of the trans- parency of water has lead to much skepticism as to the validity of data obtained from the instrument. Many conditions other than water turbidity effect the depth to which an observer can see a Secchi disc. The amount of cloud cover, the state of the sea, the seasom of the year, in addition to the experience of the observer are certainly among the most important. Even so, the compilation of data gathered by the use of the Secchi disc by astute observers has vielded remarkably correlative information (Emery, 1954). Obwiously, the readings cannot be considered absolute, but the relative values have been so frequently exhibited in the past three years in the nearshore areas of the Les Angeles region, that they cannot be considered» to be completely aberrant. This coupled with the simplicity of operation and the ready umderstanding of the results by the non-scientist make it seem that the instrument may still be of some value im any marine program. The hydrophotometer, because of the theoretical precision of its measurements, has been considered to be a much more accurate method of determining the transparency of sea water. The instrument can be calibrated, the calibration standardized, and the intensity of the light source set so that a constant reproducibility in readings may be obtained, The instrument May be lowered to any depth so that the transparency within a narrow horizontal layer can be measured with accuracy at any interval desired and reproduced under any set of sea or sky tr ' | ; ‘ ® i T2008 vfy4 rt te ' if s fr r 4 i ' } > ay } fy : ¢ - 1 4 ‘ % ew j : i mt) : yer j : Pag t 2 nal 17 By a Q : : sas i f : A int. A ’ } o8 MIgsh Yaa as it ® oe 4 " i 4 vived t phe hha Dey Decugabe) ae 4b er Maerey tem he 165 conditions. The personal aptitude of the operator is in no way involved. On the other hand, with the instrument used during this survey, many peculiarities were encountered which could not be explained and which led to light trans- mission percentages that could not be rectified. There were occasions when the instrument was in obviously clear sub- surface waters and values higher than those of the 100% calibration value were obtained. There were several stations occupied in sewage fields when no transmitted light was received, although ambient light was present at that depth. An instrument check showed no irregularities and subsequent lowerings repeated the performance. On other occasions, when in water with strata of sewage debris, the motion of the ship was such that wide fluctuations allowed no reasonable average reading to be obtained. Thus, despite its theoretical pre- cision, the photometer has inherent failings which may lead to spurious results. These, coupled with the fact that the meter determines the horizontai transparency of discrete layers rather than the net vertical transparency of a water column, a factor of considerable importance when one must relate the transparency to the non-scientist, leads one to suspect the immediate value of the hydrophotometer in its present form in a monitoring program such as that required in Santa Monica Bay. A Comparison of Hydrophotometer and Secchi Disc Readings In an attempt to relate simultaneous hydrophotometer and Secchi disc readings, two graphs were drawn using the same Secchi disc readings, but different averages of those obtained oste fara. Pel Beate OR ard >>. 3% ee tN fe 22 ream vv We pals @ ake ak gaa ksy } ; Or Pe Pee at tng Da Pea ti) soe ah Pay a wit’ CVA Tas . ' : , Tod KR bs. ' wei colt ae rs iy fod iwie¥ fae éoad sie a 19% staat i § p mw YULAY wuk ice id) ay gawen mh isensy aw ey » dpwontign ; : yO > tire . nm . ~ 4 ¢ Sartor p Pazyewn st @ + Byi-a i o*ntee: (oe, ey 62m ' | sbia Tans iM 1 ee pifivy od @Fe ‘ig ii 4 7am ug eat iy? | ley. ay d?aw Tie 67 ieee ageee . BN hatin reach tel ngmemrets tah * I ; ined vetlel sues 4 Line, We tet pe i an LTO hielo LU) of erat ok Limi sits | cilaetahaliomnd oA oe WH a ‘taplkwes aoa re i bh eae 1 iseoen | pate stan obi te wu 3 if wd ririieke felts oe es brl — swetb wie edges re - 0 yas #8 fo t 7 (Fat geDe rave dwopat easibe A % : a Sui al niet 166 from the meter. In Figure 79, the Secchi disc depths are plotted against the per cent of light transmission at a depth of five feet. Assuming the Secchi disc readings to be accurate with the limitations imposed, and the photometer readings accurate, within their limits, then it is apparent that a low light transmission at 5 feet is effective in limiting the depth to which the Secchi disc cam be seen. In Figure 80, the average of the hydrophotometer readings at five-foot intervals to the depth of the corresponding Secchi disc is plotted against the transparency as determined by the Secchi disc. For example, if the Secchi disc was visible to a depth of 15 feet, the photometer readings at 5, 10, amd 15 feet were averaged and piotted against the trans- parency of 15 feet. Of course, ome must recognize that since the transparency of the water usually improves with depth; then if completely erroneous Secchi disc readings were taken and plotted in this method, a similar curve would resuit. On the other hand, one meeds to assume the Secchi disc observer Was competent and the readings as noted are as nearly accurate as possible. Aliso, one must assume that the measurements made with the meter are true, for just as there is a spread in Secchi disc readings, there is one for the hydrophotometer. With these assumptions in mind, a Similar conformity to each mode of measurement as is shown in Figure 79 exists with this plot. | A relationship does exist, therefore, between the trans-= parency as determined by the meter and that by the Secchi disc. In some instances the relationship is not close and without a6oF és itive @ei pBiqeh mtan 'e3y {are 4 “ P 143 4:, s f if avts 344 54 { o> Sie oe 35 - yearn niger ASH 7 Fem ‘ 2 ah 24 ) ie A ? yar. wr . 72 i Qekieaier s TT Sigh" + “~@ a) a i u 5 Oe. Os " ie tte, BAIR FY 22 eft be isint : AP | (aia pine ] — ro fa” Ny. , ae ot geeges al ‘Laeree 3 ins | sift ums i » ot) yelewewk OFS8E mi 2ookdatiabi@ i vpial@ apttce np Waleriace PA = Tits ovih Laaee > ~~ n \ yo ifaeh e ¢ ‘tye | bye? me 2-@ jas) S108 yy Ta a? vegh ' 19 -Yie7a ieee irae SLR a2 hos ‘ “oi Sho a Paed : & ii ma O26) eeta “te <* .egelbee bar af Gry ir. ooh _ “ie Sawer’ Jeeee, f am eng yo 167 Figure 79. Comparison of Secchi disc readings with hydrophotometer determinations of percent- age light transmission at a depth of five feet. = itt ae Se { *y Tm s “ te aa s+thwel ( 1 rts yh tary ; m . z 7 PF +5 Live ’ si oD s ee , e P| Te S-. 02 4 Ray Or SECCHI DISC —*— — BEST Fit CURVE kr uJ LJ iL Zz > 0) Zz LJ a < a Yn Z < a = fe) fe) © v Y¥31 3WOLOHdOYGAH - 1354 GS JO HLd3d V LV NOISSINSNVYL LHOIT LN3D83d ~ ae is WW SSOP Ns Sa! 7 * . j ie J u j ii i meensty trate ane aan ate on a c ; > —— * el Ot oe ; OS S10) (HOD2¢-T 423 Me vaMzAns ea ee ape ee be ny. : et Pe | Sie es 168 Figure 80. Comparison of Secchi disc readings with average light transmission to depth of Secchi disc. (va WJ SS uJ = e) = e) ac a ie) a [a) = S ae E a WW (a) SS 2) Zz ve) a < a 2) Zz < a = ie) = Zz 2 ” a = ” z < ing = E ab o a © < 74 WW oO a Ww a uw re) uJ Oo < a WJ > < O TRANSPARENCY FROM SURVEYS OF ENTIRE BAY @ TRANSPARENCY NEAR OUTFALLS (PRIMARILY FROM BACTERIA SURVEYS) 4 AVERAGE TRANSPARENCY FOR EACH 10 PERCENT LIGHT TRANSMISSION INTERVAL — BE Siri CURVES 30 40 TRANSPARENCY IN FEET (SECCHI DISC) IAS YDMaRATEMART @ ; [A8 MOORS YAM EAS) py 3 VSM eM SR AT2MAR Ty ROAR EA THO) THIWII9 OF HORS 3TH WeHee MeMAM T 1197338 Lan Meh lo ee on bs nace’ im oo wneng.7a araaa OT LT. Pes eee ST) pe /~~eor « 169 further comparative analyses one would hesitate to say that at a light transmission figure of X,the transparency with the disc is Y. Nonetheless, there is a correspondence and it is believed that each method has a certain degree of validity. It is recognized, however, that should a photometer be devised that measures the net vertical transparency of a water column and reduces the measurement to the distance an observer could see down into the water, it would be vastly superior to either of the instruments now available. THE CIRCULATION OF SANTA MONICA BAY Statement of the Problem Of the physical factors which determine the dispersal of sewage after it has passed through an outfall into the sea, first consideration must be given to the rate and direction of transport by currents, and to the process of eddy dif- fusion. It was proposed early in the survey period by members of the project staff that an investigation be made of eddy diffusion. However, in view of the complexity of the pro- blem, it was not at all certain that within the time limit of one year a satisfactory answer could be obtained which would make it possible to forecast the dispersal of sewage from the specific outfalls under consideration. Because one major point of concern revolved about the related problem of the rate of disappearance of coliform bacteria, an intensive study was begun on the organisms themselves, the result of which are described in another section of the report of the tont You ot Sinttaed Diver ens aney tans sitkaenem dtiw Yoartaqnaat? S07 * 46 enegkht xo Lesimemet? 4 a 23 ti tna sodehnogeateM « = 08) , reel earpaek. “ c tiny te osteeh aiytees « cat bottom om, rads! 4 setesotoda «a himeie fadf ,1ovowel . bagingaoes ta youstacenged Papbigey 100 o¢% casnonge tam is yon tot a3 of FRarswen ‘+ secites fae ae vy od Dienw 72 [8086 e017 ot=) Bred Ome biesg = - alice fl t 27h We 25a amu: ies nF is 208344 of 4 YAH AOTWOM ATHAS So MOI lost. SAT ~ \ a on itt eo bare anakh eit stkuseteh @obte ezotce) Eas havea aaee ,tnt lle?tue ge Weis? veceaq a8 FE See rnittsexth tra oia1 st? oF Gee ‘aum. golive hie : en oui ie F LP ri rn eo We et} mt ae , 29S 7300 wd sdmem vd bokseq yewriee sis | rizae baengoIg cs rhhHo , ee | vi roe ir tVao75 ; ts tail Yipie toate v sta ets te vraxeiqebe wciv Af gisvewo!! « eae mti sh Ghai iw Par) 23190 Sf 38 fon esau; nzgitde af blwe> reeens en a ‘ to Entaegeite ede t2009007 ad) prog i rake » =| + aple ne wn (dor ojotes of Pires nae Laity nezono te 0 , as wih +2uK 904 aeigepableeso zsbhne €F cae | vienetk) na ,abversall @poiiias ‘eo acim 6 tlener 17 - cord? Benenagae: 5 ont, to ack oh eA? meee | eo” wee) oe ew y 170 Hancock Foundation. The disappearance rate established included the effects of eddy diffusion, although its magni- tude in relation to mortality, sedimentation, and other factors could not be determined. Eventually, an intensive experimental and theoretical investigation into eddy diffusion in shallow or coastal water must be undertaken, because along with currents it isa physical process of the utmost importance in determining the rate of dispersal of any component of sewage, and the con- centration of waste material in surrounding waters. As long as this is neglected, forecasts as to the behavior of sewage will remain largely on an empirical basis. In the investigations of the University of Southern California the rate of disappearance of coliforms under specified conditions was determined. The next problem was to establish the direction and velocity of the ocean currents, for if the bacteria were carried ashore or in any direction at such a rate that their numbers could not be reduced to the numbers required by law, then pollution by legal definition would occur. Of course, currents are important in distri- buting other components of the sewage as well. During the past year the circulation of Santa Monica Bay has been measured by three methods; (1) current meters, (2) drogues, and (3) drift cards. In addition, a radioactive tracer study was conducted on May 22, 1956, from which it was hoped that additional infers mation on the trajectory of a tagged body of water could be determined. a2 aorve to 2d osiis a iwomtindy ich mp «Vi Ag ie) ‘Aé ewott? ‘neato of w aL tes tf? tog? s WA d ya ie , SE 307 if sinshoqna t?e7 uo es3tup (id sor her aoe 27 rg 2 tS: ASL & ores , SS 9am o° 30° see 22t aft ac himson | 7S ont opi Leutne®. norkd? to ite OS > Y daricee xd «cay 2363 6s LUD i s Tho ‘ ae 330° hba al ss + pI It had been the experience of previous investigators working in the bay that currents were generally slow, and it was widely believed that they were erratic and unpre- dictable. The work during the present survey has confirmed the fact that velocities are often low, but it is now evident that the currents are not erratic and random in nature; on the contrary, there are several well-defined patterns of flow. Because of the lack of basic data from other sources, it has not yet been possible to adequately investigate the causes of these patterns or to correlate their occurrence with meteorological or other conditions. In this sense only are the currents unpredictable. Current Meter Observations Between June 26 and October 19, 1955, 114 current meter observations were made in Santa Monica Bay using a Gemware meter at depths from 15 to 190 feet, in the following localities: the head of the Santa Monica Submarine Canyon, off the Hyperion outfall, over the rocky portion of the central shelf, off Malibu, and off Santa Monica. At many stations where subsurface and deep meter readings were taken, the surface direction and velocity was also determined by means of a current cross. On June 6, 1956, another series of 24 readings were obtained with an Ekman meter between the surface and 80 feet near the Redondo Submarine Canyon. | Velocities ranged from negligible to 0.45 statute miles per hour. (Note: all distances and velocities in this section on circulation are given in statute miles and statute miles oS ; . i] I rn i ee g L* 4 = z 6 . * oe ; spicaijeswed Bidl¥etq Jo vorskasgee SA8 pees bad? a weg woke @Liswaen stew fiacrrws tent ¥ed Off ae ernqau beg> pits i ie 819" 1S OA svelied thoba wiettines Aad Yor ieee sere at neissb ¢tew sat wor i rH ° git) ne? tc ; £3 599407 te ,50n 4 a Shi bh isa sua! ed? bag? 14 * ew ie veveg -O7 é 3 7ROD ef + bo fy roe in Qual off i » ts wol? 6 ei4i2an : J+ cnOq. Dee aed Tk gh50 P : . 3 to 4 : ives red a? -*srr nd 4% 334 => ew? ws we ~ ad ' : = 7 a SHOL7 rei7 5 ne oe stim opmes ae Ne ; ei1aqnn efaeti2 7{ao Seeee wiitnvuieedD e353 : Gi 2° S shu] sere al k nol 139 STW “ae k d , Pe a ) c . stsite aw > ml ; roost eaegqee 10 vii OPT set bt nat as ‘cad on? 19 ‘¢ nM i Ss 66) 16 sor SKIS R409 24 F ‘ss BAD! es ts A solic yicad ‘saiyer of iat ore apoklet? 399 = . “we i" "impeieh cate oa ry e o io8 eyatty, Es eth POR BOE TOvea 7 i { . an be pour Oe) bad saetcet vt game: ot | 207 Re ; L ao gol¢e b.0 af pidayitasa airwl, nee. eas | se2ose Traries lre @oSnaeeld thee Paie | i _ uae rye oatim etotste San eftia beatae geo eee y 7 O} f of 9 wr, 1% ‘ 1 a 172 per hour.) Only 29 readings exceeded 0.23 MPH, and the majority were less. Many of the higher readings were obtained either in the Malibu region or in the vicinity of Redondo Canyon. On two cruises when winds were light or absent, the direction and velocity of surface currents were obtained concurrently with 28 meter observations by means of a current cross. There are too few of these to allow any statistical treatment, but one receives the general impression that sur- face velocities under these conditions are from one-half to one-fourth those at 15 feet, and that the direction of flow is in much the same direction as the subsurface currents. This difference in velocities was rather unexpected, and it probably reflects errors in measuring low velocity currents by either current crosses or meters, rather than any real differences in currents themselves. Other series of surface current observations using current crosses (without concurrent meter readings) also showed, under conditions of little or no wind, velocities ranging from negligible to 0.38 MPH. From our own results and from earlier observations by other investigators, it was evident that velocities were generally low, so low in fact that the current meters. themselves probably were unreliable both as to direction and velocity (the limit of accuracy is reached somewhere between 0.1 and 0.2 MPH). While the velocities often decreased with increasing depth, there was no consistent relationship, nor were the directions obtained of much value. With one exception, the longer time-series showed no clear oF , ‘* a , — ie] ; a . iil ody bas ~RGM ES.9 Sevepoe* Funk eaes eet, | (oa niesido sasw egakbeey sertgil ort to Yah .tastreiaeie ibn bed. looFPARADTY Gt he 10 HlgS2 witlen. oA7 oft ,faseda 26 O6R)L @2% 2bekw aotw astse12 OF bonts?do stew BS@ppaed scctiee to Ys loots tata jnersws 2 ty ensom @@ BabEkPay roto +5700 SE Blige gs inoiteifet« yuo wotie a? geent to ws) O57 Sim PEeeee wh sat! coivaee toe: Isitegen h -vieiss sao dag 4 of tisht-~ono mosi Sin SERRE ‘ rr nelis mokt te Goitsesib sia 9agi Ga st { 1A S6ORS atastis® sostiwedee Sar Ba iio) 1ib omse sd7 2 72 DRS betosqes at redté% enw o ole¥ @& sonszs ime13zao> yYiisolov web Basiebene ar 270075 rtopliss © [ss1.Vns teh? 196 + .-8149344 x0 2va20TS TRSTAls Sle Tie 10 a2acss sodd0 ee% aH ' atgue tago- Ge ee fneyiwoarneo tootttiw) Sanaa" Pasbets> ported rao ktaweeedy: so sii tl to sheds pho? teoc0 t vote oobetepas Ge HOM SE.9 of =! tsi Lune — 722 9us5 seltiosisyv (od. eottayie:ée 2a) igea wos! one 2740898 Bo =n vig setttooiwe fe Grobive sew Th epategiic sion teeteeD sit cit cist #iowet oe ,wol ve anijoerrh 29 eq Wied o(dullssawage Gidedot steisenos OS0paS9 68 VOAIL OOK $7 ' wars ec han & voteedee) eee): £3 any @o fog © 2%) ioe s#lyted ot c + t~ t xoltayv sidazrsblanod Fe Peet « bea Sel ew Gee of) Yo etosite eat? aedtise : y FA So Lwaweo he iia , “il? “ug. TOR 295271 ; i Sg ec lynne ace io sen ed is sirebiscgays ; + eutitt ena teen + die Lp yer (ant ine oda 2a8 @0bipo OS 51s eid? at adad Rew Gece i 2 -iutte+ i ¥ tivck? riizb adi unt bwonas te ee) 2 ee ee claojeeeg out ig bend | fw 90 a} icy ape i747 en" setlita~ ied RL iat ’¢ by avdetythan S°h Save t9hTS 1 ‘483 Dasencoei Dread, SOT ABsOMR | : B55 30¢) 2287292 & a aq. hee 10 si 4 @f rah 2 6 ila Fe ‘ \ 7 7 ‘tewene Hho wot vol , vei epeier ateel th @ ‘on & cry J sjiemiquo> yow VAL fedl of beseropes geRal ee oes Site ; = Pes) -f theb tetsu an Us ‘ j o i oe > 179 It is believed that the drift cards reflected with a reasonable degree of accuracy the direction and velocity of the upper foot or two of water. To some unknown extent they are directly influenced by the wind. While the magnitude of this error is not known, it seems reasonable to assume that over short periods of time, during the 1 to 3 days required for many of the cards to reach the beach, and during the periods of relatively low wind velocities which were present following most cruises, they were not deflected enough to invalidate the general conclusions which have been drawn from their drift. One annoying occurrence was that obvious errors in date of recovery were made by those returning the cards. Perhaps this was to be expected, especially since many of the returns were made by children. Such errors were difficult to elimi- nate, because at some stations returns were spread out over many days and there was no valid basis on which to decide whether or not any early find was actually made on the date recorded. Consequently, ali cards were accepted at their face value except a few which gave quite impossible velocities, even negative ones. It is for this reason that the highest velocities described for each cruise may sometimes be open to question. In general, however, high velocities at any one Station were supported by more than one card or by similar velocities from adjacent stations and the general picture, therefore, is unchanged. The drift card cruises were scheduled at more or less regular intervals, and because of the nature of the whole wy Ee? ye 7? 2% e * i sreiae wih 30,48 neat ll oad « : | ; Oc : to bed rvleb ef} Fan moval tall F bay srjsem = i } 2é63n Coe ats ew 70 aw BF ay tH ; * vd. hese eet a | Oa 5 ‘Tai? thew wy ¥ ter» ’ ' i ‘ ’ 7 itw «<« . . a: -- a i a ¢eouesy J 5 oe el da ed a if ' Te ; eae) 70 ate @ yt? f “Ay (we eh. 's an Trou om n at? y pr i re 4 qesss Wey 2 ’ acd weet ry ‘ tenet wert) yoasl ie vet dpiriee il : 3» Wa gies venque oreee U ae ~~ inetalie oor eae . 7 . Layewate WE yas: . An Ee bis _. wo tpeotte lead ® fae od ‘i 180 program, no attempt was made to distribute them according to selected weather conditions. Except for the fact that no cruises were conducted during the passage of major weather disturbances, the coverage of the bay as a whole and of the different seasons, probably gives a reasonable picture of conditions during the 1955-56 season. It is to be expected that during periods of strong westerly winds the surface water may be driven toward shore. Whether or not this is always true of the main mass of water is not certain. It has been observed by the lay of the ship at anchor in various parts of the bay, as well as by drogues at a depth of 15 feet and by current meters at various depths, that waters within a distance of 5 miles from shore frequently take a direction at a considerable angle or even directly opposed to the wind, even though that wind may have been blowing for many hours. By the inherent limitations of the survey, this and many other fundamenta’ questions relating to winds, waves, and currents remain yet to be investigated. On the earlier cruises, drift cards were released during the course of an ordinary day's work, usually between about 9 a.m. and 3 p.m. From some stations cards were recovered during the early morning hours on subsequent days. This was of little consequence as long as velocities were low and the currents were not directed toward the neighboring beaches. However, on the February, March, and April cruises, there was a consistent shoreward pattern of currents as well as an increase in velocities. When it was apparent that a time of drift for bacteria of less than 24 hours might be critical, sntiraoos ments stud. o> sian ape forests on 4 . if 4581. 2439 304 ” .2nekttbaos tedtedy yotnm 56 sgeeRa wh besoatba ot wane’ it to bes sloste 2 26 a9 ’ \rwrsve> naz) -eSso8 o suvfsia siducwtnetis inion id) «saoensa TH é Se dimen - aha 17. st} gnbsal oe .* c ise i> aloiryw ¥ irs) 12 ' 16 tte) Bate 7 wi eri ter 76 xodT ae ot roy saver ody ; 3 at742 Toon sm ML) OTe " ions ; ide reta: to | id On VasEeS « asgsct ib 4 ep 2 «ae sit 30 a? 704 ; . j } Atqe! teV Es siazv3a VO ite 9 un iI0 vse) ooh in 7 sistebh @ ani _ rh u uo slece Sides rs oo btsoua ks *. red van baie Pee a >. Orkw off GRY ' “it ¥o enor’ neroddk .s2u0t Yen Got ‘ in b Mop »tasee@glec ) Vase tas 2lar ‘a ys elie “> bax pene VOB th 6 ain 370 ave rztuto Sstipes, o89'g ten coowtsd (iltgua@l ,#'yo* Lu vine higovia ta oe aD: ww eiphec , -oom aag4 ute lt baa® ¢ Zeit val *neupe edi , vod yedeigm ¢inao wee i 8) ‘ ae? Lois .p of #8 SBNReLeeTOD or ood ancradgaypeewt Si) Tiwee un Sage ten a: a Sons thogk San ,dotel UF aunts ore aw se : i MS REG cyetteq, toawviede PATA BC s ere to sah” « ted? tosteadae oo 8 70RAR -eebrhags 5IRY 292, oy. Pull qed’ Se eee a _ ’ - —=— T 7 ” 181 from the standpoint of meeting pollution standards at the beach, it also became apparent that there was a possible gap in recoveries during the important interval of from 8 to 22 hours after releasing the cards. Accordingly, on the cruises of May 23, July 26, August 9, and August 20, 1956, cards were dropped between about 9 p.m. and 3 a.m. This procedure made it possible to recover cards should they wash ashore during the critical interval. In no instance was a card recovered early the following morning from a sludge or effluent station. This fact increases the reliability of computations of maximum drift velocities from those stations. Explanation of Drift Card Charts The distribution of stations over the bay on most cruises was Similar to that on September 8, 1955 (Fig. 81). Station charts for individual cruises, therefore, are presented only when special conditions require their being included. Stations located at or near the proposed outfall terminals are indicated by solid circles; all other stations are indi- cated by open circles. On charts showing the returns of drift cards, the station number and the number of returns over the number released (i.e., 6/25) are written immediately below each point of release. Lines representing assumed paths or directions of flow from individual stations or from groups of stations are drawn. When- ever two sets of figures are written at the ends of the arrows or along the flow lines, the first indicates the travel time in days (unless otherwise indicated) and those in parentheses give the number of cards recovered at each locality. Whenever ; i a 4+ tn aDxyabnate saliutieg varies ie tmboqiagsi s - . : a isang. gn Bow Used Fant netetde omeosd ozlw. Ee Sc of & eet lo Lavasin: fesi icant of2 Qeetub enuk a esztux> =% wo. 7 i waibresor a: i? agieacied ae new AbIBO TOL ,O8 ‘aeeih : “gah ,AL glial & «hem #70 be rq ad] aie § i ” gunda neow? snivob sien ivaw yoaul® Olu: rs¥o3973 2 old a Kaen vyooer-hrted « iw “gig! ey : fayvyetas iad 7 H ; toda? A “Vv 7% ~ Ey hee & hf “2 f 372°O £0 mizu 10 ' 7a é Or ia c P fan? it san iw 240 129 S11! fav bivtbak 10% ¢ i eal ,7an) ean tritgas isi Sa aro? finatlivo be eogesy anf, * i bet,ool saokim £ Bifeital dH £f1 ufiea ya bse “taxis seqocw oun gstata P1Sh Ww evieis is golewute eptests sealay t ula deuny ab oe0dd base (horeaibet oes stlte g-yenelt v9 tiaoo! does fa he pgveess Bae reer i ~ 182 Figure 81. Drift card stations, September 8, 1955 - a a er a | ,OS os | ognoaay V~ | HOv3e VSONY3H HOV3S NVLLVHNVW O oe (@) ‘ } € / < , ® Ivauy J / | —— 7 Ze | eve) | ye ae | SS . 4 O (a seca Or 171

‘ j it 7 5 4 ad j 4 ‘ oat | 4 — — — - — a az ; eé> t fy = white? to = : ; r .. ~ f r 1 j athe j 7 ‘ | , > -% i : é } } & L Aare | f 1 ' ¢ d ct AS@ AatrTaiaw ; : j oF } z . J d s | | ey * J f. -# ' j | | ipoaze AtCURSe | - é i ; 5 ; os ‘ { o2eoG20 = ‘ it =n noasae 6S a - c ; “ - = :. c | ' ’ 2 a Sd | : or ii - Je 23¢6n4 eo ‘ - = ; | } et tt ‘ 7 ‘- 7 i: - a i —————— t 7 2 =< « _ —— and a — ange, Ah ome pi — 183 two figures are given for travel time, the first figure in all cases is the minimum time. The second figure is not always the maximum, but represents the highest significant travel time, for it would be misleading to include additional figures for cards whose recovery was obviously delayed for reasons not directly associated with the currents themselves. Cruise of September 8, 1955 When returns from the first drift card cruise were plotted, it was obvious that the cards released within 3 miles of shore | behaved in a manner quite different than those from the 5- and 7-mile stations. Accordingly, the region has been divided into Areas I and II (Fig. 81). Area I is the more offshore and Area II the more inshore portion of the bay. Points of release and recovery of cards from Area I are shown in Figures 82 and 83. Most of these cards drifted for a relatively long time, 5 days to 3 weeks, before they were recovered on beaches which, at this time of the year, were still well populated by late-season swimmers. Conclusions as to the early paths of flow from these stations might be uncertain were it not for a few cards which were picked up only 2 to 4 days after release. A detailed time-sequence of recoveries of cards from Area I indicate a current which flowed north along the central coast and then west past Malibu, depositing a few cards along the shore as it went. However, the path of flow after leaving the vicinity of Point Dume is uncertain. After many days, the cards, now widely scattered, drifted back into the region between Zuma Beach on the north and Palos Verdes on the south. One card appears iave1? so? asvin O8%n 25 NE 5 fmintaika od? at I HS = Om woty 2b sqauw wisi avanh b' of s orien wolls atu tieoqsbd ad] R | a wolt Yeo dvaq sa? 0 1O¥e ms 399%A mistvooms ab @ aes oted Ased bed tiab ) bepeeen 184 Figure 82, Drift card returns, September 8, 1955 Area I, ~ ud a; -* * SE Or Sv [oo 9 Fe | 2S swovas WO 7 ‘ OGNND3S 13 WOU ; SS ys | N S85 . ee - pee acer os ae pan \ a LEVE avasouNvay SN ‘f , arg Gees OL 31N390\ Id\_\S ov3e BObeday OL = (2) vI-O} is v VSONY3H \ fara aug ( NS \ } \ % \ 02/1 ca [ \ 9ere ene HOV38 NVLLVHNVN \ ta \ \ ae A3Y 130 VAVId OL / } \ WOINOW vNWS Woud (+) S|-9 / / ) a ye Z| aang: ened ss | —— i ae OErE- {gg Se OQGNOG3¥ 01 \Q) GLE» O oP \ WINOW WINS mous \ 27 OaNn9das 73 \ ie \ E x os y S | \ | S e/g | \ \ “~. 62re \\ % nein Wows Gav 31 OS (a 91 $ x [ \ \ —— \ ie = SS ~S i b I vauv \ eee | ee were SS6I'8 YAGWIALdaS 2 r 4 : ' ) fy ~ ey f ee a q : Ritu? ‘ , 4 Artie ATAAS kept Te) Cio ; \ i i ; ; pesate agganin ; é 4 & u a ‘ : A A RE SA I IN ’ ] ’ f i > |. I i ) nd) oe Ol nee 2274 @30R35Y fal 185 Figure 83, Drift card returns, September 8, 1955 Area I, bet . Xe 4 ' a is 7) ee ee STH S3083A SO 1Wd y ae: Y / ee rd fa / 434 J30 WAVId OL / Ps, INOW WINWS 7 pte) go WG- ee ee =i Ae eA a \ \\t ) SNE eee! \ | \ NVLLV HOV38 VWSONYSH \ \ \ | N HOV38 NVLLIVHNVYAN x aX x ) ie ¥ \ Hov3a_wWnZ | -——— yy, Ae) eee ae a aN ore oa bel ee | Saris \ iB aes on OQNNO93S 13 \ \ \ SX (2) \ So woud dauziavos O!-9 \ =~ \ SI/7 x “ Ber Howay VNNZ WoI-g ; tien ys \ Ke Se SS6l‘8 YSaW3LdaS eae Sl ete 4O 3SINYD x PE SNYNL3SY GYVD 1LsINa Se) = ve 1334 NI SYNOLNOD WOLLOG er ene as agit eas oe S37IN 3LNivis ee ee ee eee 2) [5 2 i} ° ' HOV3B Wag neinv se . SE Ov Se SESIl a + —* — oe ee ee oe 186 to have escaped the bay on its voyage and drifted out through the San Pedro Channel. It was recovered at Alamitos Bay two weeks after it had been released. Whether the cards were trapped in a large counter-clockwise gyral extending well outside the bay, or simply drifted about for a time offshore and then were carried eastward by a reversal in current direction, is not known. Inspection of Figures 84 and 85 shows that in Area II a well-defined current flowed to the north in the inshore region. At least a portion of this current rounded Point Dume and four cards were deposited near Zuma Beach. ‘Two cards, one from Station 3427 and one from Station 3434 came ashore near Redondo after 10 to 12 days. These may have been carried along with cards from Area I and returned to the bay only after a relatively long journey. A total of 334 cards were released, and 145 returned (42%). Current velocities were generally low, of the order of 6 miles per day (0.25 MPH) or less. Cruise of September 29, 1955 An entirely different current pattern existed three weeks later. The only similarity to the September 8 cruise was that the bay could likewise be divided into areas, in this’ case three, depending upon the behavior of the cards released (Fig. 86). Area I lay offshore and included all of the 7-mile stations but one, and two 5-mile stations in the southern sector. From this area all recoveries without exception were made to the south and outside the bay. These recoveries are shown in 7 . — a x Be A A ? " : tuo bePi 27D beh eucvov sft wo wad sag hadgoss ql wt val eepometl 96 Dexsvoso: zsw tI ‘teecads orbet, Fe row 2bren’ sae. farte oc? segetss aesd bad 22 388 Liow gabkbaeatke texye ocf> ico lo-aedapes Sgzes es al uM siotetio o#tt ® apt féduy bottind yiqnke Seyved ame t1972W> HF ‘(eeteven a «oc so oskrah> pew" ¥ ‘ th -awour For £22 oa {i estA al edt ayode Gh bere es 2rehl 16 getioaee fv siofbeak adt #k Aon Sat of cell) Pos t3we backtal aiot boleteos I9qaGn 203 LiTOY «© Saeed 7 oF 27 i93454 avs sta6n Getreods ! raw BS2ao 100 As onn> BESLE noeteiet std SAG tur nokyere mos? an ’ vat yam, sage tveb Gi. o 9+ 1/8 obnobet om ‘t bDonantex bite 0 Sana mor! jac A9tw anoly io EE oot AMer ¥! 2 a xrstis Ving Y . banivtey Cl bee’ Beageetes 16 SLE is istas 10 2s to ,wol yPheaemey ¢ : i Mi av rao IMD, | _a@el xo (it \ vat ong wl Ke €& 3S tors fg 2% 2¥sow gomls Detzckxs Geese Peowws tao tstize witved bad si? esw salugo 8 weemeegee sc) Lboke yine 37 ceso ahdd ab » sees Ofek Do hivis of sabwedet bivess gate thysy BAR Te 19 :¢ sf2 HogyV got iaeged ~ P ° odd Yd £Le ete too! oboe o2oder ty vk a apm mest ,4otooe nasdveoe Oa at aeottele sthier cos be sa t of shaw srow desTqsone twodr iw za kanvuoss ; e. ig vn? weede ote Bpliewooss 2 aT ged. add a) Cine Salt » ) aan tah yp 200! nog MARA) Sel Bee Oe 187 Figure 84, Drift card returns, September 8, 1955 Area II, i TMH S30N3A SO 1Wd HOv39g OGNOG3u HIV38 VWSOWYSH [ HOV38 NVLIVHNVYN OGNN93S 13 (01) AVO |-SYH PZ. II V3uvV SS6I‘8 YAEGW3Ld3S JO 3SINYD SNUN Lad GYVD LAG 1334 NI SYNOLNOD WOLLOG S31IN--34Nivis € 2 | ° | We YOINOW VYILNVYS ae — 47 te Pad ~ : a - auauTa A ORAS TAIRG | 30 32iURD Lt Hon te PASART: ates 220! 8 ASEGMITISe _ ; a ama oe a a PN! Sa I | TA {> Fa Shae — A, A j 4 / wens ; ) = a eo + - a z 72 a = FO : 4 ' es [or " 5 j ! ’ ' , _ j = f : : ' \ . \ ~ . LRA @70r?y¥ aout, 5 ra — ie, - r ex “ - On 6 Be he = - =a a = a ——— -_ a we a — = —= = os eeetentimeting marcel _ —_ ay 188 Figure 85. Drift card returns, September 8, 1955 Area II. HoOv39g =~ OGNoG3u es Me r (1) HIV38 VWSONY3H } HOV3G NVLLIVHNVYN OQNN93S 13 SS61‘'8 YAGWILdgS 4O 3SINYD SNYNLIY GYVD LsIYa 1334 NI SYNOLNOD WO1LLOG S31IN31nivis €: 4 | ° | We VYIOINON VLNYS se i oer . we ke 40d fw 2 > : — ie : : Se > is % Ye ra, t : {Uv tig » al \ ~ wy “ may C) i 0 * 7 ‘ ws it a ‘ f ; ar a r whe 7 er ae ‘ pet Tt — f > 1) ol \ . ry PP LAD mnie { Hi “sy ty ps ‘ ~ OO 4 : i Ms hat { i hs 4 ‘ ~ 712) rms f ts y - fot } I F _ ¥ ‘ ' ' b> " 4a 3 ~~, ut { iy a 1 ; ' nh ‘ Ana \ « (yas ‘ he ae ( I { : - = \ : : . 4 a ; Lf ite. i nen eal ‘ ho AC} bs +. \ Ut & % p- : ' aN. ' ee . ‘ eS ' Py . ? } ‘ihe Me. J : : | 7 | Zz : ee or t - j j > a eee Soe . t oa y ts SP ee ae at i. 2. irene 190 Figure 87, together with those from Area II which drifted outside the bay. Of the 140 cards released in Area I, 45 (32%) were recovered 6 to 31 days later along the southern California coast between Long Beach and Pacific Beach (San Diego). Area II (Fig. 88) is an intermediate one consisting of three stations in the central and southern half of the bay, from which cards were recovered both inside and outside of the bay. Although substantial numbers, 23% of the cards released in this area, were scattered between Huntington Beach and La Jolla, an equal number were picked up on the beaches of Santa Monica Bay mostly between Manhattan and Malaga Cove. Cards recovered in the bay indicate a southerly component to the inshore drift and maximum velocities of about 6 miles per day (0.25 MPH). There were two recoveries at Venice from Station 3516. These are not necessarily related to a diverging current in the inshore area because the time of drift was long (9 days) and the actual trajectory cannot be determined. Returns from Area III are shown in Figure 89. This area lies inshore and includes the 5-mile stations in the northern half of the bay and all but one of the 3-mile stations. From all except the most northerly stations the cards came almost directly ashore with maximum velocities of about 5 miles per day (0.2 MPH). Returns from this area give the first indi- cation of a divergence in the water as it flows toward shore. The divergence will be shown to be characteristic of Santa Monica Bay whenever a general flow from the west occurs. On ji p > — . ' > bs7i:36 dostdw 11 ssi1A 07} oad? ciiw sadteae? .ti a ce if @ nz Oenaoios ‘ft oft 7 .¥ad See - s1edtvon sit weetiga gotel ave 67 ¢& Ds 34*vp96s Ss une) doask (120ee bee docs wm or7ed fenos «he ; io BA ¢ Osi TALIS PRE . eka) I ao Yad ont i ad wesd?eoe Le: a1ti d? a: auoitee :Biua bey enki fidod w abuso th ‘7 g ‘tomy otedus Mawoas rh notagnitn nsoewzed DHDewetias eint wl eat a! ~~ £ om = 7 of 70 q 29 ow 3Sde ‘ sol £ 7¢ GatzarmiuaM wiead witvea , fom egtasd {ltedtwoe met Yad aed ti sbrs0 ve jmixvewm | Af “ny Sit * ’ 2 ed. ’ I r Be* ve oF ay ¢ or ate noy? eis t "ye > £ “rie é 7 “AL R1SaVie £ vaofnai sti fos of ban (2 caw P7kul i tmteaTtTepD : iT] S18R84 Ae twodes [i st74 Mot] en2eze ’ : fara slia : ioeiscot bes s10otee ol * Ti ie fe) ; wa if ae Yad is an S938? #@00t7i ’ m732gn Jaom eo) xg * ¥ fr tuade Ia eektiso! umbtin dtin scotize Tie | Svin SLA *ti5 “oz 7 or 2wiras (Has $9 (i bs wolt 8 gk ew of) al apasg2ovib a; ie) i : istrerseteds> s3 at agwoda ua Jigen oom Pema — . ne : : ~Y shee = .21u229 teow 30) mos! wold Setenog e aavens ; — went... AD) oe 7 191 Figure 87, Drift card recoveries outside Santa Monica Bay, September 29, 1955, Areas I and II. ge rae ebietoo 4 q {It boa I peeth ,tPk gh: to ca i) LYALL a ai / DRIFT CARD RETURNS CRUISE OF SEPTEMBER 29, 1955 / Vi A 6-99 DAYS (33 CARDS) 6-31 DAYS (I9 CARDS) e > = ° _ 192 Figure 88. Drift card recoveries, September 29, 1955, Area II, SS ° 18 30° 25° il 7 T a { Tar T | SANTA MONICA BAY ° | 2 STATUTE MILES BOTTOM CONTOURS IN FEET DRIFT CARD RETURNS CRUISE OF PN OO a ~————~, SS ~ SEPTEMBER 29, 1955 AREA IL SEGUNDO MANHATTAN BEACH HUNTINGTON BEAC TO LA JOLLA 9-30(6) HURLTANG TON BEACKN2 (1) SSX PALOS VERDES HILLS POINT VICENTE TO DANA POINT 6 - 16 (7) Nie 7 é ps - . ~ — = - — en _. - = = _ - onwd = _ : : 4 - = ‘ d 7 -— i . a: 7 ee 3 7 ee a nn 0 Ce a ns dh ea ae a ee le Ei eee ee oe a ne — oP a ef = 193 Figure 89, Drift card recoveries, September 29, 1955 Area III, an ‘ er7eor % \ 2k.’ _astravor ie te rai70 : a 27A ' i) HOV38 WSONY3H x F HOV38 NVLIVHNYN OGNN93S 13 SSG6I‘62 YSAEGW3SLdgS 4O 3SINYD SNYNLIY GYVD L4SIYG 1334 NI SYNOLNOD WOLLOE S37IN-34Nivis € 2 ! oO ' We VYOINOW VWLNVYS ase oc Bll AMEQI|I Se ——_ — =the} od a< 0 ~ . ‘ ‘4 ee | eMaAUT 39 GRAD F3AG } ~~ Sos q es _—_ ab — (eS r4) ies 194 this cruise not only do the lower stations show a southerly and the upper stations a northerly component superimposed upon a spreading of cards due to random dispersal, but returns from individual stations demonstrate beyond question the existence of such a divergence. After diverging,the water flows out and rounds the points of land at the northern and southern limits of the bay. The earlier anology between Santa Monica Bay and a bowl with water spilling over the edges is valid whenever the bay is being filled by an onshore drift. However, it will be shown by later cruises that the currents frequently flow either from the north or from the south and that during those times the bowl analogy does not apply. Cruise of December 29, 1955 The results of this cruise are presented on a single ‘chart (Fig. 90), because of the 288 cards released in Santa Monica Bay and of the 49 (17%) that were recovered; all but two were returned from outside the bay and were scattered along the coast between Long Beach and Rosarito Beach, Baja California. One card was found floating in the water at Avalon Bay, Catalina Island. The maximum velocity determined was 4 miles per day (0.16 MPH). Two cards were picked up by boatmen in Santa Monica Bay the day following release. Each had drifted about 3 miles from the stations of origin and were headed in such a direction (west of south) as to take them out of the bay had they con- tinued in their drift. During the day of release and during the following night and morning the sea was calm. There was no wind of any conse- yw 9) Vy) ee 1% a et i aa 1) KEY = ~ Vicedtve2 a -olln Baobectm tamed af? of vino 2608 a | hozngméesave tooooghes yy Praitigon « stok reds reqde! esxsutsr ferd”,.fe=19¢71D MONRE oF svh «=iascs 10 gaiteside st? eolicesp teorad Staafeuomsd evolista Iapbiee Stew SAT Woresors Sse rons vib @ dave Yos e nrett ron oft D2 Seek Teataioe 17" ghagor bia ® ¥ i = a ; z= - Aw nolors Wktyee sei 4% Jo artgtiag geghe dt seve aakibiqe Jetew ariw fwoo : bas ysh sc tae ¢ ttiueb guatene me Yd pelt? Beked at tad aa asvencdw f A) esnexwws off Indt esehoap Peek «oO : ‘in ef (2iw iia ‘ os * ; ine aiaoe ods mez? £6 Gipaw ges wor -odtie\wolt ate wigqn you aseb yaddama Iwo St eomk? edods yerng + «S329 7 SLAP Le ‘so Seve SaS9G Se sei td i ginal oi béeastes ele B88 oft te saweoed - a. ut ted [fn sbetSvosdt Srew cals ‘> sft 30. Ore Vau i ! hezsatigos stow Dig yee on? > moa? Seastsa) re ' stat ,dosek of D5A8GR, Tie Aves! pros nsawted f2e0c one ts 1stow s@¥ mk Qmttact) ocx exw bia ond she bowtarretat ytiooloy mmeeam oT tnetel ni tated a 4M O1.0) Yad zOq noth 6 erlwoM ates? eh @eageed +o qe beaaig e208 zbred ¢ ne atin § Yuode BefRbad bas 2g “a 8 pakwol Lod: 7a : bbe dose of Babood 2 ~¢ niyese 30 anoiteare od, y - ar. at Ps -ne> vodt bad Yad @f% lo. feo «ote edee @F Be (StmoB | 200d) Phin sbedd ahd Aes ee f wy or fuia subwoilto? ed? noraeo pes seentes 10 ab adt ga! wt ree 7 Hi - : ny ° o 7 / I Ok a a ak es oe ©, -s0r90 "ay lo hale of cae CENT) eee ee 195 Figure 90, Drift card recoveries, December 29, 1955 YNIIWLV2 18 DAYS () y, DRIFT CARD RETURNS CRUISE OF BacemBeR /29, \955 O- 4 y 38-59 DAYS (3 CARDS) NO RECOVERIES IN SANTA MONICA BAY yi Jf Ae 2-31 DAYS (21 CARDS) (24 CARBS) Co Be BEACH , B.C. ———2 — sh emma ale PO / é = a re ell 196 quence and only a barely perceptible swell was present. Between 9 a.m. and 1 p.m. on the day after releasing the cards, the VELERO IV recovered several of the cards and Sighted at least three other groups of cards floating in the water. The ones recovered were from two different stations and had drifted only about one mile south from their points of release. All of these cards were returned to the water, but were not subsequently recovered. Under these conditions of extreme calm and weak currents, the cards were observed in clusters of four to ten or more whose radii were of the order of 50 to 200 yards even after nearly twenty four hours of drift. Cruise of January 18, 1956 The current pattern in January was diametrically opposed to that on December 29 (Fig. 91). Drift within the bay was strongly to the north instead of to the south. In principal, the pattern was reminiscent of the one on September 8, when currents flowed to the north and then turned west past Malibu and Point Dume. However, the currents on January 18 were more strongly developed. On September 8, a great many cards were recovered in the bay. On January 18, only two cards were found on the same beaches, but twelve were, returned from the coast between Point Dume and Ventura. There were four returns from Catalina Island and one from La Jolla. This fact, together with the low percentage of returns (4% from all stations) clearly indicates that after escaping from Santa Monica Bay via its northern portal most of the cards were carried well out to sea and to the south. -: {¢ = : ‘ ; Lb, 41 : c Se 73 Tu s i 7 ie J ari my) 8) S2nunted ! ad — . go> roe etdadé matt Raiqat . a two Licw heated eane, €bg48 9G: * t - 7 Age; £97 Figure 91, Drift card returns, January 18, 1956 acer (Br yauutal: Semmes: (>. Rie TO es VENTORA 77% H EME 10-56 oW 8-I0 (6, yNIIVLV¥2 DRIFT CARD RETURNS CRUISE OF JANUARY 18, 1956 raf = § , ¥ ’ i Ya { ' . = ste ’ é * | J } \ eat tr rh a ae rm al i Los y * /) 7 24et WwW. CRaD Pye * 2eUAD Ace @ YHA Wes ‘ 4 ad * - a a 5 * ; - oT Pe) oes Eh até cea ee 198 Maximum velocities were of the order of 3 miles per day (0.12 MPH). This figure probably is somewhat low as the coast north of Malibu is not frequented to any extent at this time of the year. Cruise of February 16, 1956 This was an extra cruise not planned as part of the regular schedule (Fig. 92). Twenty cards were released at each of three stations, at the proposed terminals of the sludge and effluent outfalls, and one to the south, seven miles west of Redondo. Only one card was returned. It was released at the sludge outfall and picked up near Lunada Bay, Palos Verdes, sixteen days later. The travel time of this isolated card cannot be considered significant because the area is one of high cliffs and rocky shores, and recoveries even in the summer time are likely to be infrequent -or delayed. Its direction of travel, together with the poor returns from all three stations, seems to indicate a dominant southerly flow from the portion of the bay in which the stations were located. Cruise of February 22, 1956 As on certain other cruises, the bay was divided into two areas determined by significant differences in direction of flow (Fig. 93). From the southern portion of the bay (Area I, Fig. 94), a few recoveries were made at Malaga Cove. However, one card rounded the Palos Verdes Hills and was recovered at Torrey Pines, eighty miles to the south. No cards were recovered from three stations of the seven, and the percentage of 4 4 est tan to webs 40% to wane enadboo las waren 2 20 #0) 3ettwanne ai yidsniew Syutat?d ear “ie t Sas? ia 1? MasNeyrett ton ef sdile# te. tesa ~Taey ody 2s) «Sf Jeeeess wit > aa begaalyG t> vtD SYIX9 2S Soe sw 259%89 Gian att) siubeisae Sere3bs Hiei ean étars rosie i fe? eF ogo fe > ftnsulite 4 hnwshs. cow eee bres v! ) bo HAR as Dn sae sor go beeoty Baa | culefre edt ta ztdt ni [overs Ang 1+ ) £99TRKLa 2onag ois waoed tasotlinyie: hegebi«: d toanes biao Ee wwO5ST bas .2s70te ea “4 (> dsid fo one ; Tsepey tal a0 ab yts i 2 om? 198hee off oco>g 3173 dicw w9ene? .for0xs 2 mitastzth eff Oo .& STg2fhaek OF SEaae , ac! + eegd? ifs os ‘tocdw ctl ao sft tn ew ; a? moxt wot? vit -~beTavol show ei .b8 Y1gu3deF “ Vit 2awW Yee ats , 1oe lets gedie nlabseo ae! suonsaeteeh josc mise wd benbursyet + t it £80 .giad ‘4 BOTA? Yeo Si? ta’ anh sedtibhatias ont mo "Hho . re vrawoll ov.) cael RM e sah oeow aAsiasvess? | s » a parol Fr iv voonz see bog 25 igh eviigs¥ eolst odd 2 bi erin: fo79vO994 s¥ow 2h4e9 off) ditege Mee Me Seiko Vidger. 9 fo” a S SHINAI Oy hee anes aa) te mes 2 199 Figure 92, Drift card returns, February 16, 1956 d - oy Sew eo ; _ , ~— a JOS ISS | ‘ b STH S3083A SO Wd HOv3a ae OaGNoG3y My HIV3G VWSOWNY3H HOV38 NVLLIVHNVYW OQNNS3S 13 \ 9S6l 91 AYVNYss4s L JO 3ASINYD SNYNL3AY GYVD 141d | 1334 NI SYNOLNOD WOLLOG S31IN 31iNnivis € z | ° 1 Wed VYIINON VWLNYS "Se a Pe a 0 0S es ce a rs eed ia —— a a a oe Ov Ze © S2iVUAL &i YRAUSES4 200 Figure 93, Drift card stations, February 22, 1956 f i = is ore . re t ) ators L230 i i ,os} ———. HOV38 OQNOG3Y HIV38 WSONY3H HOV3E NVLLIVHNYN 2S SS ai OaNnnoas 173 \ 9s6l'22 AYVWNHagS vet Jo 3sinuD 14luyq 4O SV3uV 13343 NI SYNOLNOD WOLLOG S31IN- -31Nivis e€ 2 ' ° 1 WE YOINON VWLNYS ae 201 Figure 94, Drift card returns, February 22, 1956 Area I. ws) +0 ->Y Siege ° 18 30° 2 25 SANTA MONICA BAY ' ° ' 2 3 STATUTE MILES BOTTOM CONTOURS ,IN FEET DRIFT CARD RETURNS CRUISE OF FEBRUARY 22,1956 AREA I EL SEGUNDO MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH SS a TORREY PINES “\\ 14 DAYS \ (| CARD) ne! ee ee i e ’ : D 5 ne f a i : , : v = a 4 . i ‘ * vf , 7 - 202 returns from the other four was extremely low (only 1 card of 14 released at each station, or 7%). These facts combine to indicate that a well-defined southerly current waS present which flowed past the Palos Verdes Hills and carried most of the cards south and to sea. The one 86-day recovery from Station 3435 is of no special significance. The adjacent coast is rocky and precipitous, is seldom visited in Feb- ruary, and a card easily may be hidden or overlooked for a considerable period of time. Within Area II (Fig. 95) the general trend was toward the shore and there is a clear indication of an inshore divergence similar to that noted previously on September 29. Because of the relatively long travel time of 6 days from Stations 3949 and 3950 on the northernmost line of stations, a small gyral may have been present in the northern portion of the bay. Cards returned were only 55 out of 272 released (20%), although the recoveries were better from the northern than from the southern stations. Maximum velocities were 4 3/4 miles per day (0.20 MPH). Cruise of March 28, 1956 On this cruise the customary stations were eaaumed but with one additional group of cards being released at the southernmost entrance to the bay, about one mile west of Flat Rock Point. A large number of recoveries were made, 243 out of 550 cards (44%) being returned. Because of the large recovery and of the relatively simple current pattern, a slightly mm) 4ae ; i os é aeAC0C r — avVS —— * i al a beno £ vfoo) woh ekomattes enw a¢o? sedio ess nowt Fe snidmed 2tie ost (2% ao ~noltatée f989 72 inseol sa seS2q tae fas tes Fred iro bet ctob... abana - 203 Figure 95, Drift card returns, February 22, 1956 Area II, cS VE OQNOoG3 K SINUTLSsd) Gay a sida 1334 Ni STH S30N3A SO Wd HOv38 uy (€) 7 HoOw39 secnaan HOV38 NVLIVHNYN Ss OGNN93S 13 i Vaey. gsél'Z22 AYvNHasS COME SI {Ale|®) SYNOLNOD WOLLOE S31IW_3inivis (€) e-9 yan 1 ys om we YHAVUES ret . 7 ey" “s ao tiie ita ae. - _ PYUAUT AR GAAS TAG Fintan ' f e: FO 921veD ty . ‘| aa innas@ AgtEY?eJe ? — —t— 204 different method of presentation of results is used for this cruise. In Figures 96, 97, and 98, returns for groups of stations are plotted and the general areas of recovery from each group indicated by brackets. The dashed lines on these charts and those for succeeding cruises separate areas of different times of drift. Several salient facts are evident. From all stations including the one off Flat Rock Point the general drift was to the north and inshore. Cards were recovered between Topanga Canyon on the north and Malaga Cove on the south. Only one card was returned from Malibu and none from outside the bay. Although the general trend was to the north, some evidence of an inshore divergence can be seen. Because the divergence was not as prominent as on other occasions, the spread of cards in this case might be interpreted as due to a littoral dirft which carried them farther to the south than would have been expected on the basis of random physical diffusion alone. The maximum velocity encountered on this cruise was 5 miles per day (0.21 MPH), but most values were considerably less. Cruise of April 25, 1956 The general pattern of circulation within the bay was Similar to that on the preceeding cruise, inshore and to the. north from all stations. Here also returns from many stations can be grouped together and their graphic representation Simplified. 1 t . ; jo 1 A # ~ yo A uy) re ooh J eidt sot bead eh atimena to notistustaay jo Hono ts 2qno29 20] aasmhs: ,82 bos .T? .O) egtwQna mt a 013 yievers? 16 seth Javeres of? bee bettolt”d stn @ nly wo eonil boriigh OMT .etsiceid 7d bareol hes qua 1) seote Sisiages. @etiuto aoibso.ows 167 sted? ‘YE2b Yo eomlt fe anotiste tfe mort% Fae@bive our otoacl dasiias 1678 i enw tikab Ign2enen ott FRbot 42: ial 320 sao Oc? Qae F ip nsewisd bstevosa2 SIee mine: ssordank baa Of 2e8 .tvo2 sf? oo ove) agelew brs «iron on? no nOyoOaae fyo mos} anon baa odiier acti | niet @ew bres Se qsHoe ,«txren odt of sem beset I,uvoen silt mavolt iA ae r i ' ect save nea -neea Sd Ged sozSn19 y sioMank te 19 38 2n0t2zso°0 167970 WO 2B fn2 ota 2s Jon Zzaw iy ouh 26 Osi saqisteh Oe Janie 9 eid? mi ealzad Tag i q ¥y divoz si} 09 te@?apt mods GLI iniviw Pisib Leg obaveq sobags1 to abeg@ otf 4 bolosaxs aesd svad Bias 2 ; .Soyls ao: @ ¢aw 2stuin eid} Be betetnvuocas "itu lSv apie Sf da:shbiencs ssw Sekew teom tud ,(AUM 06.0) ¥eb vem . Qt?s .te Legos ‘* 8 -aaw ved od nidsiv moteeteouro to maee2aq 1at269g SR wi? oF twe stodent ,SRhwio gu tleensag en no tedt OF 32 af . ra a : s - ks : yogm mov) enseder orle sxth .Saottete Lie we7 i ad : i: tan : 7 dotisinsreiget sfiiqeda whett Lee Geaeepo? bequar od . oa Ve I Ey - ‘ S ri t are <4 vere wer TY J 205 Figure 96. Drift card returns, March 28, 1956 - = _ PE nl —+-7 cevsi 8ZOb OaGNoag3ay \ \ x Jo ax =< raAc SAVO ¥ = SS HIV38 WSOWY3H | wovae NVLIVHNVIAN \ OGNNS3S 13 ae, ——— = 9S6| 8c HOYVW JO SSimao SNYNL3Y GYVvdD LslYd 13343 NI SYNOLNOD WOLLOG S37IN 31iNivis 2 ' Wa VOINOW VLINVS— se a oS a SS € ° oe les —— q0 32 iil ce! SS a we r WATS AtounOY } - i oanooms J. ft ,F ; iy iS,g7 ~ zs + | | ay = j Na | AY MS >! x = is ¢im 220879" eae! € —— - 206 Figure 97. Drift card returns, March 28, 1956 HOv3¢e OQNog3y HIV38 WSOWYS3H HOV38 NVLIVHNVIN = 1 ix \ EON OaNnodas 13 9S6I‘82 HOYVW 4O 3SINYD SNYNLIY GYVD LslYud 1334 NI SYNOLNOD WOLLOP L S31IN- 34nivis € 2 ' fe) | INKS] YIINON YLNYS OES ) . 207 Figure 98, Drift card returns, March 28, 1956 VE HOV38 WSOWY3H OQNOG3Y HOV38 NVLIVHNVYN OQNNS3S 13 9S6I'82 HOYVW JO ASINUD SNYNL3AY GYVdD LslYdd aN 13343 Ni SYNOLNOD WOLLOd S37IW-341Nivis € 2 ' ° | WE YIINON YWILNVS Se ESil CUHUTSIAR GRA T 10 AShUAS 84201,8S HOxHANM 7i>gt ' ? } ' sey © | 208 Cards from the southern half of the bay (Fig. 99) were scattered mostly between Santa Monica and Manhattan Beach, with only six from Redondo and Torrance Beach. All the latter cards originated from the southernmost Station, No. 4197. From the northern half of the bay (Fig. 100), recoveries were predominantly from Malibu to El Segundo. A number of cards were recovered from the Manhattan-Redondo region, but all of these came from the same Station, No. 4208. In general, the trend of the currents seemed to be inshore, with a moderate northern component, but on this cruise there was little evidence of any well-developed inshore divergence in currents. The spread of cards from each of the various Stations could be explained on the basis of shoreward move- ment and random dispersal. Because of the predominant inshore drift from all stations, 53% of the cards released during the cruise were returned (276 eut of 520). The maximum velocity on this cruise was obtained from Station 4203 in the southern part of the bay. From here one card was picked up at Santa Monica 29 hours after its release and on the afternoon of the following day, at a point about 15 miles distant (0.52 MPH). From all other stations, the maximum recorded velocities were less, but in some cases were appreciably greater than on previous cruises. For this reason all of the most rapid drifts on this cruise are summarized in Table X. Bat tas J ree ir) i nacsvadee® bas i a HR 78 te 4 pi Gee ¢ a5 ¥ t taj)“ varel iis G¢) : t sat of cUgs6 be: oe al sets ry ~ +7 ted axvedtuce site eo2? ebiad Tna2 canwt se ¥ijeton beta ceantT tun Obrobsl moat keene ‘,oa stit aot? peFarte nett 4ore Gy ai i wont VOkenee@Om besevooeo! Se @ oy ee =4 ac? taersasa es 5 Aston 73208 sfaiste i bet f ae to sogebivs sim Trt .&3n08F% v ‘ r ~~ crt : if ‘7? io s2u22gn vay ® ej c ; adres »ae aa 7 {oce 4 a0 =i is0lsv SHmL xem Oe asin s¢° ta oe Detoiq) ame & obwe 6 i? Ye nooresttq Stiae ita ao Hom 62.0) ttazvekS Om , at ' “% : tztrvao r a sO700845 M i im gait 1288819 Ts 1, lsnes¢gae fel * , : 2 ng etlinl? bigni tenom@ ofy-16 ta ? k stdat wi box a - aa faa 209 Figure 99, Drift card returns, April 25, 1956 gan Yul bubs 22820 y ts 4 - / / a o0er Pl Aa S275 / &. JOS 7 OSs HOV3a ama OQGNOG3u \ Szvel\ €02r HOV3@ VWSONY3H bt | = NVLIVHNYAW IGS 1$S | OGNNO3S 13 je \ [ < N \ Ne [ ss IS \ % ‘ \ ; \ \ Se SS = SS. ee = ee eee OF Pee ee ~~———~909— | 9S6I'SZ TIddv eT iia oe SS ver JO 3SINYD ae re SNYNL3SY GYVD 14IYad es Son Pe Ne pe | +334 NI_SYNOLNOD WO1LOa a eke Se —-09—— S3TIN 3inivis \ es Se 4 € ro 1 ° i} INAS! VYIOINON VLNYS ase Ps ia . bs d | 2iAAU T3A GAAD TIA 30 Seiuno aeel eS IATA “oe 28 MATTANEAM / ? ' STV ear nJABe ACOORDH / oy ven _ 210 Figure 100, Drift card returns, April 25, 1956 rraqA mt ae Priest 00s Si! STH S30N3A SO 1Wd 0S io HOV3E OGNOoG3Yy HIV38 WSONY3H \ HOV38 NVLIVHNWN SAWO v-I x / / ) S2/el wes \ 602r | | ~—_Sevel-— a og) © CST hee ee a SS \ Z| FIG - gs / OQNN93S 13 y, . /szei \4. €lZy SAvd S-€ SS) | \ \ love L Ries ha. | Se So ee eae al t ee ee a Shh S66l>Se. Way eee NN Ne] i a Se —ooe ber dj0> SSINael re : iO SNYNL3aY GYVD LsIYd 13343 NI SYNOLNOD WOLLOP ea Yap oe ae ~~ —-09—— S3270IN 3iNivis SS — 4 € 2 ' ° 1 HOV nenv Wea YIINON VLNVYS de . 4 he | Tet evnuraa csaa tana fo 4-7 7 ; 30 S2turRnD x ij Wr. Fi a ) wa gavias uaa fk ea - a =. | - . ~ | zt 2 A t . = | | Se : “ 2 | : f ‘ ita, _ = { _. >. =. CESS D AG — > = = tae _ 7 a ’ é 7 —— . = ; 7 a a 7 7 zs a, j ese 7 E = t 7 = oT we pm j a, we Rae ee! eT ny 211 TABLE X MAXIMUM VELOCITIES OF DRIFT CARDS April 25, 1956 Station Point of Distance Time of Velocit Recovery |Travelled |Travel |Miles/day| MPH 4197 Redondo to 2,54 mi. 0.50 Torrance (4 cards) | 4199 South Playa 0.39 del Rey (1) 4202 0.45 4203 Santa Monica 0,36 (5 cards) 0.52 0.37 0536 0.43 4204 Wili Rogers Beach (1) 9 27 8 0.33 Sunset Bivd. (2 cards) 10 27-29 83-9 0.37 It is to be noted that these relatively high velocities are ali from stations in the southern and more inshore portions of the bay. No such velocities were recorded from any other station; most of the cards drifting at a rate of 5 miles per day (0.21 MPH or less). ear) |) aes ‘eaten Teves! SI F ai 8-8 \ (iad cian edleticseappe' ay SS —a = \ ia — 2 $y ee a yee } A Pe eS. * gS | ee he ee | 9 | Pate . | Q a e4 0 o-£8 | Of-TS Loolew Agitt, yhewstat e+ eee e108 baa mss yeah € 4 % wy Sait ) oe3 Stew Bolt toolsy ab3e0 31 nati bab ) “aQese! *yo In = 4) } =o WOM Mepiy el a a ; Vv Rum TAM aah. sasieaae nowt 5 ra gy a i eo A ee (ie hae 0 ta ko yasoosh | | a 4 a it bezon ad of SEa pone zrot (ebm “gyals mtaoe Ct) posh Isb ' —— pay SLs. 3 ino stent (hxe5 1) wane? szicoM winae ( abyeo *) ———————— | axsgon cle tr) ioaed ov iG Seanwe of ad edt 20 a roltatea ree vab $9q athe 212 Cruise of May 23=24, 1956 On May 22, 1956, an experiment at the Hyperion outfall was conducted using a radioactive tracer in the effluent. Between 10 p.m. and 3 a.m. on the night of May 23-24, drift cards were released over the usual series of stations in Santa Monica Bay. In Figures 101 and 102 are the results of these releases. Thirty eight per cent of all cards were recovered (95 out of 252). They demonstrate a modification in direction of flow from the April 25 cruise. The predominant direction was still inshore, but there was a moderate to strong southerly component from most stations instead of a moderate northerly one as on the previous cruise. With few exceptions, cards from all but the northern two station lines went inshore and south. A few rounded Point Vicente and were recovered from Lunada Bay, Portuguese Bend, and San Pedro. From Station 4257 the one card returned was from San Onofre. There were no recoveries from Station 4263, as these cards probably went south through San Pedro Channel and were lost. Another point of evidence for a strong southerly flow from the lower half of the bay is found in the fact that along the three southernmost lines the percentage of recoveries decreased with increasing distance from shore, from 50% to 10%. . From the northern lines of stations (4248, 4249, and 4250), the cards were carried more directly inshore to the area between Santa Monica and Playa del Rey, but from the line just below (4251, 4252, and 4253) a definite southerly drift was apparent. aget \ RS=ER" wt trotted GORRe SAP Pe sromtisgze AA seek SS aid +9 ig l Ve (BEI BE BHOR I? evitoack hes » Bntee betout bhiah hSHES SEM Pe dagta oct fhe . aa bas «mq OF ni smokjute Bo elder Iaven s(t 1970 PeeeeeeE ols to eticees adf oie SQL Ban [0. 2954 “% gl vad go 2oznctet } ‘| oa ce) bexsvoord uxow 2baao | is ass weg tdnis “7 bf tooth mk WORSSORTEBOW a 2741) 200ma5 “ont OSES nektaotiy tenakmaberg 987 .08.5> S L[AagA, on2 mon? gnuosrte oF sta2ebeo s 4a” cz ted setae Lee: statrebom s To beehemk ‘BHeitsts % >< or? raouoaued vie snoiiqooxes wet MPEW .eakwae exotve:d 97 BO as site re stofznt tasw @em€L AGEIATE OWS GION? 2°! é+ ted Lie moze be,erooos a tew Bas sfuenty waind bebwe wst A aa moet ot het de? bas’ ,hned cescqatso8 eae at sient 422 mem? sew boouvis: tied Sao Bae TUGH me ebua> sawtt ee gEOSE Bostste wo: eatsavooez oF Re saat erae bao Reeeed? osbet ace oy: vor? dfvoa Taow ‘a cor) wolt ¢iaamiaer grote & 2? sonebeva tnied, : rnols teh Phat eet “i bugo? ax ved. add) te Pind. 7a8 -a5¢ene8 ¥0 omaha isd of) eenil Peommredsuog | conk .orgale mo2? Soustatb yrtesotoek ain ci Ored Sas , CRS ,AdSR> ahoktare Fo esnht neers ton od? moxt aeze 9h ‘of saatiiad CLiastkp Sxom bokzieo ora Re: bagi sali off mort ded ee feb eatt boo Se eaw ttétb ¢ fredtoo ot hakioe, ? Siccren * any 1 vied ie iba j 213 Figure 101, Drift card returns, May 23-24, 1956 °o 18 30° v T 1 55 ° ' 2 STATUTE MILES BOTTOM CONTOURS IN FEET DRIFT CARD RETURNS CRUISE OF MAY 23-24, 1956 EL SEGUNDO SAN ONOFRE 13 DAYS MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH 2-172 TO 3 DAYS PALOS VERDES HILLS JOAYS SN Demos) i ¥. 214 Figure 102, Drift card returns, May 23-24, 1956 ¢ ve STH S30N3A SO Wd HOvV38 OGNOG3y HOV38 WSONY3H HOV38 NVLIVHNVN OQNN93S 13 L - LNSWIY3dx3 SAIL OVOIAVY- - 9S6I‘v2-E2 AVW 4O 3SINYD SNYNLIY OS |SS Vie GdvV> talyud 13343 NI SYNOLNOD WOLLOP S21IN__-34ANivis (3 2 ! ° 1 We YOINON VILNVS Se LSI AE —— ——— . GRAD TAO bone’ eVAUTSIN 40 321URO y, ie ay i mentsc-es YAM fo bane i SVIT DACHIAH- ‘ “he ¥ ? f - | : } y ‘ tn c . 215 The only indication of a northward littoral drift was given by a single recovery from the effluent outfall station (4255). From here one card was found at Trancas Beach north of Point Dume 18 days after release. All others from this station made their way to shore between Hermosa Beach and Flat Rock Point within 2} to 4 days. Because of the long delay in recovery of the single card, its path was uncertain and likely it represented a change in current pattern occurring some time after the cruise of May 23-24. The maximum velocity to the shore within the bay was lower than on the previous cruise, about 5.2 miles per day (0.22 MPH). Cruise of June 19, 1956 On this date 525 cards were dropped in the usual pattern and of these 279 (53%) were returned. This was to have been the last scheduled drift card drop under the contract. From the 7 and 5 mile stations (Figs. 103 and 104), cards drifted toward the shore with perhaps a suggestion of a slight northerly component. However, those returns, together with the ones from the 3 mile stations (Fig. 105), give strong evidence of both a divergence in the central inshore portion of the bay and a split into two branches, one running north and the other south. Returns from Station 4313 (Fig. 103) suggest either a large counter-clockwise gyral in the northern portion of the bay, or a drift to sea west past Point Dume and a subsequent delayed return into the bay. Moderate to high velocities were encountered on this cruise from several stations, including those located at the | are hg ‘th Lsaet¢il Soewiition s ico wottaotbah yieo ¢ Le p foting tansy tiie aft nor) vaeveoss elgate 5 yes Pas noavg AA ODHYT 76 lwwo? 2aw (565 of Seek moRA t i not? snedio LLA 8 -oRar! tte syn SL sowvd | ms 9499 \eeoinagh moawtre! S204 3 Yaw 2zisdi obsm 4 of off Yo Saas .evab ! » £5 wkdtiw satot 29% nisiisony aaw dtaqeeze taco 91; 141 to Y29Vvo0S3588 4 ‘197764 SSIS ME SRmetio « boinsessaqay th Vee ‘ » 2 ; ;. HOLS VAM IS Seto ody iotte sak? smok BE d ait aenyiw erode od; Loolev munikaen sm tod aelta (8.2 thoge .seacirro ‘NOLVSid sd? oo Bega mest | tC ,@L anh] tum = [sueu eft gf hegqeth s19ow sbiss 268 steb ekae ee > mf \ Of “ow, ERD .beitwier orsw (FEL) OTS paste RiinOD eth) gabe ti 1s2 T2235 bolebudsa Fae " - ~ : s \ bos SOL ,;@58%) sneitaty slim 2 bee 7 sd? aoe fof 3 SaReWe RP agqaiicd titiw erode oi? .biswor Be aity N1S302 »OPSTSt seeatt . woll .dnenoqmos ¥iasg é > svi » CROL) nbd) wtiste silm © odd mezk oan otek Lettieas, att wt sooaaguevib » dated te ean 7 i LEAL ORO geenkonssd Ow? ofa: lilqe #« fas yaa ae [LES Ge29nt2 worl eqaysed .dtuoe seria 1k (aay), S#twisehs-rsiaes geal s sodhks Sam ig 77 oe 990 09 PS Sto eed ait Jo notjzeg) azeue SG oc) OF OL SINT St Hoye LAO Te ewpSs bine «. Bite, Seg WAS Bee ti oe Leal sdmeogres 9" See rao ney iiehd ot Saaeneee Py Ay a > 0 ped ie a - s * *, dl ’ Le ” - a . Sf7 Se deteno!l one) BLS AE fists mh dy Ov = : i vi i) rh : - ee or ee ee ee eee een es te ¥ » 216 Figure 103. Drift card returns, June 19, 1956 — ZUMA BEACH 3-5 DAYS 11 (| CARD) 34 be 4313 W725 SANTA MONICA BAY ° ' 2 3 STATUTE MILES BOTTOM CONTOURS IN FEET DRIFT CARD RETURNS CRUISE OF JUNE 19, 1956 EL SEGUNDO MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH PALOS VERDES HILLS Figure 104, Drift card returns, June 19, 1956 NO ant or | —600~~———-—~~ ee —-—-—-~——~——— ~ ~ SANTA MONICA BAY ' {°) ' rd 3 STATUTE MILES BOTTOM CONTOURS IN FEET DRIFT CARD RETURNS CRUISE OF JUNE 19,1956 EL SEGUNDO MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH N 2 PALOS VERDES HILLS 218 Figure 105. Drift card returns, June 19, 1956 " a = on = : a be STH $30N3A SO Vd SAVO II1-'S SUHY, YH 1I-YL fe (0S HOvV3e OQNOG3Y eee VSONWY3H L HOV38 NVLIVHNVN OGNN93S 13 save —O ‘ Sumer H 8] SS SS, 9S6!'6I SNA 4O 3SINYD [ jaa NI SYNOLNOD WOLLOEd S370IN 31iNivis € 2 ' We YOINOW VILNVS se ° Se/9l SNYNLAY GYVD L3slyd Olev ees Se ee i (GYVD |) SAVO 6) HOV3d VWNZ ve yee = 7 —vaa ’ - ; a de HDA S4-AMUS IQHAS ) SAG e if i H } ™~ = 1 2 S =... | ory fi { | 7 iff i Ty; i. 3 A> Aw a é . x ' tz t —_—— r ‘ a aver 7 ~ < 219 proposed sludge and effluent outfall terminals. All high velocity returns from these stations are summarized in Table XI. Cruise of June 29, 1956 In connection with a salinity survey of the inshore area, drift cards were released on June 29 at each of ten stations along a line three miles from shore between Playa del Rey and Manhattan Beach. Station locations and results are presented in Figure 106. Sixty per cent of the cards were returned. With few exceptions the cards drifted north and inshore, coming to the beach in the area between Santa Monica and Playa del Rey. The drift of only one card, from Station 4458, ended at a point south of its place of release. Seven returns are of special interest because they were recovered on the same day, between 7 and 9 hours after release. All other cards were recovered the following morning, on June 30 or later. The velocities of these seven cards ranged between 0.38 and 0.54 MPH, or between 9.1 and 13.0 miles per day. The significance of these high velocities, as well as those found on the previous cruise of April 25, is discussed elsewhere. Cruise of July 26-27, 1956 This was the first of three additional cruises made for. the purpose of extending the drift card data through the summer months. On this cruise, as well as on the two following, cards were released during the night hours in order to make possible recoveries during the critical 8-20 hour period sveld ons aoinoM peruse 8.0708 notwolict sf} Bersvess1 sis ‘Ciss ted7q ZEA ae! fT” Uvrmhm a ; a Lins ; i, ‘ ed indy { -Qiatimis? Listivo insuttis bag sybots Ge it Mos taawine pte enoitsts seod? mot) anakisl ¥ 6cet ,eS savt * 65't! iodani ent Yo vewnwe viinits2 « dtiw nottoonmms @ diitsta met fo Megs Je PS en no boeasisy srow es > £ysiht apswied sied2e sort) astin seat? nti’ if @’ivesz tae anottaso! a rst@ floss aade toe ebzas sAY to THe asd + tx} -OOL Bimpia ne q Stofteak Bus dAtsom Bev 7keb abhiss. et 2 wkiqagzs wet dee GS9wIsd £°° iS mx togsd sity oF { Chb anktde22 most sbeas sm (no lo #2256 sat sas9162 io eoels | to mtvee Satog « Fame isw ¥odt saunzed Sasasteat Iai i2 19 938 enigies as tS9tis esuoed ? bia T woowted .vyeb omsz add no’ Bae * 185 o5v92 seeds Ye eeaktisol -1stal.s0o OF mg 4, meewied ww .HTm 52.0 bus BE.0 -deowtad by ;tecTsoolow Aged spent to sonactiingie sat .veb oq tiqh& to sakgs® auoives4 eft ao bavot szons #2 ig _svetweels besensee 2202 . 3-08 yin Soe ; : scivi9 feaobitht. 293? Yo Dee? of? enw aint . i 4 + ated bray P)iah ego enkbnetxs te ean bie 5 Lweo 3 1) ao an lisw 2s ,eeinze side oO _edtnom 298 m of a9b7o nt ated drtséa sean jatzsb ren intizeg sod OS-8 Laskiivo ost! poke ghia he ent "8 9) | yates 220 TABLE XI MAXIMUM VELOCITIES OF DRIFT CARDS JUNE 19, 1956 Station 4297 4298 4304 4308 4311 : ——— Area of Distance Time of Velocit Recovery Travelled Travel Miles/day| MPH Palos Verdes 184 |0.78 Bluff Cove 12 (0.50 Malaga Cove 123- 0.52 (10 cards) 85 0.34 E1 Segundo 65 0.28 Hermosa (2) 9 3/4 0.41, E1 Segundo to Hermosa (11) Santa Monica to Playa del Rey 53-9 20-28 65- 0.27 “J wW oe pL (eo) e wW Nw tx Saat | be puttemene emp, ar aes 2cRAD) TAA 30 SR TTIOOISY UM TXAM. oa ae = cores Grr ct) yiizetev . a Key op k't . eons t25G Yo sesA 93 : tonk Padest: | BekievsxT | YiIsvouss a apie np —— . if ipmaares \abieed LN” Sian = 433 a ee B\E | ' e¢hae¥ soled : t ayo) Viwlh | | bd oe 2 He - “ —--t wrermcneees Trae aN Se a | ; m * | ; bS\E E-4 evo. spata. at. 0) bS ey Cabreo. Of) ; PB hes a ce Rae Nee . += S a) Od | obnugad sy > 7 j yi: Ml cile a fae ) Cs) seomral i ot ohauged Lz att OG) el v " ty =i ~ iy + = Se P) ) ad J 1) el. io bY in BE Li 4 $0) 222 following release. On the night of July 26 between 9 p.m. and 1 a.m., 491 cards were released. The station lines on this and subsequent cruises were spaced slightly farther apart to include more of the northern part of the bay. A total of 227, or 45%, were recovered. Once more the predominant drift was toward the shore with a moderate trend to the south (Figs. 107 and 108). Some cards from the lower stations escaped through San Pedro Channel. However, there was no evidence of a divergence in the central part of the bay or of a westward drift in the Malibu region. From Station 4474, 4 returns gave velocities of 4 to 4 3/4 miles per day (0.16 - 0.20 MPH), but there was one whose velocity was 123 miles per day (0.52 MPH). From Station 4475, 2 cards gave velocities of 63 and 12} miles per day (0.25 and 0.52 MPH), and one anamolous card gave 16% miles per day (0.68 MPH). Cruise of August 9-10, 1956 The current pattern on August 9-10 (Figs. 109, 110, and 111) was much like the one on the previous cruise, in that the cards drifted toward the shore. Only two differences in pattern were evident. There was some divergence in the central part of the bay with a weak northerly branch, and the drift to the south in the lower and offshore portions of the bay was much better developed. This southerly trend is well illustrated by the lack of returns from Stations 4507, 4508, and the three returns from 4513 (Long Beach to Huntington Beach), in the lower offshore portion, and by the fact that ve. Mi napwied OF vlvl tc tiigte oft oO (sbgetes Raine nokepse2 ef! zeoley $19w ababo [OB . lm “2 ‘Yani Vigwuils beorc ‘ow 2eciuz9 tuevpoedna Eg iif HO Pted aredscon * ig stom sletank w 2h so , TRE mt Deewod aaw ftin uimobs7q eddy s75n 4 bog VOL, wey) city {1 of Gmez? sists b3ee ‘ eva? beqngee enol ts sswol off moxt ebm vsb qa to wageshbive : xait ,29vowol ttoolesy hen an i S°hh mortss? ow 7 yo, 39683 Bod , (HIM Os,¢ ‘) Y¥eb 19g sekia CHIM S€.0) vad’ 207 Pil. esw yi Loois# 'S 6 esiidions | gbhapo & ,2vhe me (So 20uGLOMAARE St mo .4 f S¢.0 ‘hoe £8.20) va a 2 ¥ab 1989 2ske gcvl Din? seeauh Jog . 5 ce 5 Z . * VOL .eptt2 OL Jlaeqva no fisitaqd tay tanvo Sie S2EUSG #BOkverg od? no sro ott stk] Agum B ‘tb ows Yin «storie od? brawot Se) }i7b aby tOEtOVED smoot ¢hw stedT .insbive stse aya fonead Yfasttazon dAsew a dtiw vad sit to t1eq | srodetio bas tewol sit ab difwoe sds of F¥E55 ~ j ra Virsidios e£c Dujoteve 1933ed dsum eaw vag i 7% moxt anvursy Yo gual ad? yd botextewcee Ee nacre” 7 i AV } - » fee 2 eee nes 223 Figure 107. Drift card returns, July 26-27, 1956 STH S30N3A SO Wd HOv3¢g OQNOG3Y HIV38 WSONWY3H HOV38 NVLLIVHNVYN \ SAVQ cere SAV 2-% | ~ \ — ee - vOTMG 2 wel TGe ra e | F ‘ ' yt . a aC) ya i . ¢ F | J ’ f | ' 4 : | f | y . vig 3 / f ' “ee j ; i f ; \ ~ { fa ) i VA a . 3 j k \ c f ~, : ' r i r. " Oe~ A ~~ | TING + \ h \ \ ‘ 2 ot + a | FA { i. yi j 5 ’ we al " é gua’ . , ppt , ¥ i y~ 4 ‘ is ” he os il 7 U me |. - toes oat ag manele th ad mente om ne tin ‘ ee z a —< o te a eee me ee ee Se De 7 225 Figure 109, Drift card returns, August 9-10, 1956 . LD 5 eros my # ; \ 4 7 ve ee et hall « = y 1 I } . ree i ; Red ‘avy e ; | 7 : ™ N dtCi ,OF-8 SawMBA yatiseto>: b2«> F2inG =. POE o1sgk f iv AP nd ADM 0 tks ALM a ied Bet ° 18 30° Isa NTA MONICA BAY ie) ' 2 STATUTE MILES BOTTOM CONTOURS IN FEET DRIFT CARD RETURNS CRUISE OF AUGUST 9-10,1956 EL SEGUNDO MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH PALOS VERDES HILLS SAN PEDRO LONG BEACH TO HUNTINGTON BEACH ‘ . ae 1m e . ’ pte Gh ae ee eee ee a ce * ’ * . 4 weary Fs 2 wg toe * i J, d | | \ Ae Fiat ~ “, - fi we — oF HOARE DOS : AI MOT OME ' | | i es oe oe ea © cs 4 a are win i" ‘ee Si “2 vs - > So rn’ eee ——— 226 Figure 110. Drift card returns, August 9-10, 1956 aah 2 . , AROL ,O1-0 SauguA ,Braites D5: ° 4 40’ 35’ 18 30° 25 a Wr ] ai T UF rrr To sh im Tir = T T ils = T 5 | ANTA MONICA BAY i) fe} i] 2 3 ere ey STATUTE MILES Os BOTTOM CONTOURS IN FEET Ir xe DRIFT CARD RETURNS CRUISE OF AUGUST 9-10, 1956 34 S00 | EL SEGUNDO MANHATTAN BEACH HERMOSA BEACH REDONDO BEACH (l PALOS VERDES HILLS oy —, n 1 n 1 L 1 eee eee | 40’ 35’ 1830” 25’ P07 Sea. ~ ~~ ar 5S) i ue rt nes “ A * ve Bas r be ' a Ve rm ; cn ss New i . f fa a j 2 rf f eae ' Mey a A ers. 7 | oi 1 a a ‘ ia 1. J | Sey [ey soe neh - oe pti ‘ Aye : — > a, § He | Pa + ’ ! sacs , air : | } pin noel tenet tometer ‘eta 227 Figure 111. Drift card returns, August 9-10, 1956 ,Ol-0 seugaA ~@nzestex biao tirsd ——_ < - = SSS HOv38 OagNnoGg3ay HOV38 WSOWYSH HOV38 NVLLIVHNYN OGNNS3S 13 9S6I‘OI-6 LSNONV 4O 3SINHD ~SNYNLIY GHYVD L43INad 13343 NI SYNOLNOD WO1LLOP S271IN--31nivis ) | 4 [ op ERM mE eUAUTSAQAAD TIIAG | _f_/. ge ESN | =e 40 a2iuAD | Ae a iy | gaer,oi-e TEUOUA VS: + Pat ie = ; y J be —) " AO & at ty fe a a } i f / & 38 1, | fs Nh eS : } ; i { = a te ves if ae Paid } ; j \ 4 j BIE fo , J i és ot ' ’ ; f f \ H H } i = POG &) ?. | HDASG HATTAMMAM J - 2 [ j . ; i lL ff e%agg © } AZ 5 2a i ff! Fe, ’ ; J ‘ a 4 2 [ } : A “S® Tt: « a | c . poate asounsn st 4. “Ag. ; j ; re ok ’ 228 only one card from Station 4502 was picked up (near Portuguese Bend). A total of 491 cards were released, of which 154 (31%) have been returned. At the time of writing returns were still incomplete, but the number of recoveries is sufficient to make it improbable that any important departure from this description will occur. Maximum drift velocities were from three inshore (3-mile) stations, 4495, 4504, and 4510 and amounted to 5 3/4 to 6 3/4 miles per day (0.24 - 0.28 MPH). Cruise of August 20-21, 1956 At the time this report was written returns were incom- plete, 52 cards out of 491 having been recovered. However, all of these returns are consistent in showing a strong northerly trend (Fig. 112) with no evidence of divergence. Many cards, particularly those from the outer stations, were returned from the Malibu area. Two recoveries were made about 30 hours after release, and all others were at least 48 hours after release (including 15 from the sludge station and 3 from the effluent station). Maximum velocities were 8 miles in 30 hours, or 0.27 MPH from Station 4638 on the southernmost line of stations, and all others were less than 0.17 MPH. Drift Card Results from Sludge and Effluent Outfall Stations Current directions and velocities from the sludge and effluent outfall stations are of particular interest. For this reason they are discussed separately in this section. Results from each cruise are presented in Figures 113 to 125, inclusive. | 2S! - i a § * ** . o> , , s2ousut 30% 1968) Ge bewotg 2sw SOD mottare mot) biso 3 > he (FTE) PEL Aobdw Yo beagsloxn e29w ebrss £06 To Letod | )19~ entutes Qakiiaw to emit off SA .benawtez st tooloidwe st eeitevooss Yo sods afd tod ,eteiqmoogs zid? mor? siePanqsh tastscqmrk yus ts207 sidadotami £8 SS ; | . .wsono Ifkw aok . Calim-£) gsedenk seadt mor? grow eotitoolov St24b oumk b\f O-et O\E @ oF Bedmwoms Dae O!ch bas ,602h Leh ‘\ -noomk Siow answFet weettizw eaw Sxr1oqos eidd emty ont ay (oh Jo too sbuad SOG . qnozjt2 « sniwote ni $neicizuos o1% ehawis: seesiy .tsyewoh be 1eve9a7, mead guived .sonegievib lo aanme@bkve on Atiw (St! .9fi) bast vine Siow anoidsinz tot¢u0. 98% mor) «2odi vlsaivotizseq ,2bmae eben Sisw 85i29veo8a owl .eots uGilaM edt moxt bon tose! tk s1usw epedifo Ile ban ,oceesta1 19tis_emod 0F : \ tokiste esabwle 989 még Tl antbceical) veselsa t3tis Ome oiew a9itloolew temixeM ,(noitate tnewiie sf7 goals sit co 8£8b gobsese mort HI °S.0 10 ,eneeel OF at cacy asel s1ew apedtto Ife boa .snoriata to ott taome c , » . HIM auoitat2 IfetsuO-feegtti2 bas opbul? meget 2itueot bred” eden iene a bin souls oft moxl esttiootev Sag eqoltoeséb das 19D) eidtd 10% .+esretnk telwottusg te ozs anoksate Sle tino. ; > & etivesi .nmottose ekdd nme ini szaqee beseuseib 218 Neds n ~ovieutong ,2SL of ELL aorugtl ak betapanxq 2 » sokw rie © * aw on - 229 Figure 112, Drift card returns, August 20-21, 1956 p cA ,en’s STH S30N3A SO 1Wd Jos HOv3¢8 OQNOG3uY HOV38 WSOWY3H t HOW38 NVLLIVHNVIN Ss OQNNS3S 13 £ teeteeis a ees A 8 ye ee 009° | 9S61‘oZ-er LSNONV he er ees oor Q 4O asiInyod : ve VE SNYNLIY GYVD L4IYd i 1334 NI SYNOLNOD WOLLOE kee Se ‘eae, eae (> ra i} fe) FEET: Wed YOINON VWIiNVS ; | Sze ESI se OP Se eo sa TTAMAAM re a | i 230 Figure 113, Drift card returns from sludge and effluent outfall stations, September 8, 1955. inmeultie bas bule moe? @nxwis- : 3230 5 > =< , ‘a a - ae > tedmetdge ei t Jis?tuso | os a HOV38 WSONY3H HOV38 NVLLVWHNYWW iss | L OQNNO3S 13 L | | SS6l'e YIaWaLdas val JO-4SiINdD ° lea GHVD L4iua 13343 Ni SYNOLNOD WO1LLOG S27IN 31nivis € 2 \ oO ' We YIOINOWN VWLNYS pss VE se re aes ly Fe Be) vats : fp t A : / ; } 8 i r fi) f \ fh ‘ \ 3 4 i i y se . . ' : 4 - Lat , 4 HSAS@ atcve Nas ; i owe ose ad i : e : * " « av “pf =r eta 7 SS ny ra 231 Figure 114. Drift card returns from sludge and effluent outfall stations, September 29, 1955, & se ~ra? fasuists bas snbule mori enti " o t i ete 6 20r ,oS sedatetgee , 200% HOV38 OQNOQG3y HIV3G WSONYSH QuVD!1 SYHb2 HOV38 NVLIVHNVYN OQNNS3S 13 JO 4S indd : SNYNLAY GYVD Lj | 9S61'62 YIaWIALdaS e 4 13343 Ni SYNOLNOD WOL1L08 S21IN31Nivis € 2 ' ° | We VYOINOWN YINVS ae ecosicananee~ Snag 2VIRUTSA OSAD 30 32ivAd 922! 0S AREMATI32 TAUAG ' - 1 ; bo i ae - i : i ’ ' : . ‘ + t i" { H ‘ a - ; ws yes a ; “s "4 pti Zz — = ae a | : —— =m rr &. ee eo ' a 232 Figure 115. Drift card returns from sludge and effluent outfall stations, December 29, 1955. »el@l ,©S sodmasetd ,enotiata Lieituc F i eek < e — | S ¢ ‘ogo. | 1 S374 SIGMIA oar ' Pee. | | | (2S '49v3e OLIuVSOY ei ©) "WOds aYVd 1) Dee pore 6b / / Saf rae {| ee | i (HOW3E~LYOdM3N OL — { 4s _ --49V38 NOLONILNAH YO OG eal =n WOU 4 SOYVD €) = Hov3e aes ‘i Oy l€-6 a SS sancday YY \ I) \ i es = \ = \ Bite ae = \ \ ) Bias f ¥29 SSONYNaH \ \ as \ \ i \ | Ns =e > ~S 23 NWVLLVYVHNVN \ \ 3 > CELE ) ®@ \ (aa — _ \ a See VADAN oanno3s 13 \ SLE. ‘ \ ey \ \ | \ ay | < ‘ Ne N % \ | SS se \ i Bs t ¢ \ SS6I'6e YSIEW3I550 s be JO 3SiNYD 7 | [- = — 2 SNYNLSY GYVd LsIdG Ky me ie oN ~\ SS L334 NI SYNOLNOD WOLLoOg I ae SM 210 iVLS = € r 1 Oo j wae _. ie es 40 32iUHD | led | tt . 220105 RIEM3II30 0 Of Cane 7 : | : , ad ’ ae, Sep \ i a ee ee 2 233 Figure 116. Drift card returns from sludge and effluent outfall stations, January 18, 1956. tasuitie boas ogbula most entetes buss T2ha0 ,920r ,8f guaumal, ,eccitsta Iiattue 0s HOv38 =~ oanogay Wa \ HIV38 WSOWY3H HOV3G NVLIVHNYN OQNNS3S WU NLINGA WoY¥s NYAL3Y |) 9S6I'81 AYWANVS be JO 3SINYD ° “ISNYNLSY GYVvo L4lYd | 1334 NI SYNOLNOD WOLLOd S3J1IN- 31Nnivis [3 2 | ° | We YOINOWN VYLINYS coe OE Sil ce Pio eae Se ; if 4 ee ie > Po {ARUTSA GRAD TIAA | | REP 30 32ival ; | : 4 | f; ~8801,8) YAAUMAL f pe eee om | z = | 4 7 Sa Mon MAgr a | hod ; / A > aa fAnUT MEY = 4 te ee } r Lo ‘ | | | : yeas nesta / ~ saad j i . ; - ’ 234 Figure 117. Drift card returns from sludge and effluent outfall stations, February 16, 1956. » » Ov Sv. | T I he a aa | / ee 7, CL / / (S3lvis3 S3GYzZA SOT1Vd f io, WON+ NStTL SBN) ) oo ENE Ne OP 7} = \ vd Se SS >= 0s - SN ees \ = os a oonoasu ae ( j | SS as ‘ ie J \ ROLES ~~ aa \ a ) ra ae \ ba \ ) af : oe ae of \ ct eae ae \ Ms ee ss t ——— 13S Eee \ Ie6E as r co ‘ @ ee x [ Oanno3s 73 se AN ¥ | \ \ Ss 7 kee \ \ NN x x \ Ye) \ \ L x \ ne \ ~~ \ \ a = | \ "3 as \ Se eee |e =~ ~009~ || ( cee rt nn nnrnntnnrtnt (uc unnr nnn nts Si iui\clicnr it nists! (hats e-——-——-—— = eS —O00E— 9S6!1 91 AYVNYas4 N bt yep 40 3asinYyo — +e SNYNLSY GYVD LIANG ; os ay L TN SAS =o eer 1334 NI SYNOLNOD WO1LL08 ee ee ee rm L CeIn Me Wi a SO ES € rd | ie) i} | PEYE: nainv INAS YOINON VYWINYS ; Sv Se PE ero SE Ov os ia os 2URUTSA GAAD TFIAG » | 3 3G S2tunS tf ain eas Saar ia. = S2¢1 81 YAAUAASI 2 | | # | : . — , j . = ; co bug R i Ps / 1 r 1 | . H > j 4 s q H » 22 “; = Si i i * ve ~ * a ” t # a a : apie a ee a { { es, — ve Pa faa = eh Dy r f ; a oe 5 i & ; : j = = * a > eA 8." ig =F a> i = f | ae, (exes . } f = ; | ret ! A i : = * nase eran f ; ) + j E i “ | =. | | : ' i : ; > : f | aa fr c~ | , ; ’ Be Nein . —- 237 Figure 120. Drift card returns from sludge and effluent outfall stations, April 25, 1956. SS ve 0s oe Sl HOv3e - OaNnogay Ay \ HOV38 WSONY3H HOV38 NVLIVHNYN | OGNNS3S 13 9S6I'SZ TlddVv JO 3SsInYD 1334 Ni SYNOLNOD WOLLOP L S37IN-31Nivis € 2 ' ° i} We YIOINOW VYILNVS ise SNYNLAY GYVD 1L4lYdd 10S SS ve B2ee),cS AGA f / § ey he et O 32iVAD in A 7 f - . } | t ; : 1 ! 4 icomsrshe & | | | ——? | ; 505.6 | : HAS MART AIAN | J O28 ; | 4 ! ; j ' J | . , f jf | : # / f H2eSe ACEH / i : j ; t j } ; f “OC Se r 5 i 5 : : ‘3 € { ' ooe ! ~ \ 5 ‘ i} ) i er | ¢ 5 ) ' : 238 Figure 121. Drift card returns from sludge and effluent outfall stations, May 23-24, 1956. Sz STH S30N3A sl ao) OOQNOG3Y nova VSONUSE HOW38 NVL aL Male is¢ OaNnnoas aa° + ———————_— E 9g6l ‘Ez-22 AVA ve 4O 3SINYD SNUYUNLIY GYVD Lala 13343 NI SYNOLNOD WOLLOG S37IN 31Nivis € 2 | te) 1 We [VOINOW - VLINVS s. * 239 Figure 122. Drift card returns from sludge and effluent outfall stations, June 19, 1954. HIV38 WSONY3H WGid-I HOV3G NVLLVHNWN OGNNS3S 13 9S6!'6! 3NAr 4O 3SINYD SNYNLIY GYVD Lala 13343 Ni SYNOLNOD WOLLOE L S21IN- -31Nivis € r4 ! ° | WE VYIINONWN VYLNYS se MEDI h * Yi 240 Figure 123, Drift card returns from sludge and effluent outfall stations, July 26-27, 1956. wed aytwe’ fy > ttrxwW 7 ~ ie * . Vint, ,2@uci! % Li FTC. 2 ISG HOV38 OQNOG3Y HIV3S WSONWY3H HOV38 NVLIVHNVN OGNN93S 13 nae AN \ or ee ee OS6li-Je-92 Ming “2X. 8 4-0 a JO 3SINYD YNLaY GYVvVD L4lYa 1334 Ll sange noo nelto9 a oa en ~o | ae nave Wa YOINOWN VINVS sz SESil SE io) SS Sv weoA aN et Meo Al te 241 Figure 124. Drift card returns from sludge and effluent outfall stations, August 9-10, 1956. - z he STH S30N3A SO 1Wd OQNOQG3Y HIV38 WSONY3H HOV38 NVLIVHNVYN "SUH 8S -LE OGNN93S 13 9s6!‘Ol-6 LSNONV JO 3SINUD SNYNLIY GYVD LING 13343 NI SYNOLNOD WOLLOG S3TIN--31Nivis WG YIINOW VWINYS *TARMA SHAD T3IRO if — 242 Figure 125, Drift card returns from sludge and effluent outfall stations, August 20-21, 1956. q & ~4 Hov3e OQNOG3y HIV38 VWSONY3H HOV38 NVLIVHNWN OGNN93S 13 961 ‘C2-s! LSNONV 4JO 3SINYD SNYNLIY GYVD L4lYva 1334 NI SYNOLNOD WOLLOP S37IN--34Nivis € 2 ' ° 1 We VYIINON VLNVS se S—— S———— —— a a a a ce ee ee 0 e Se -_ ‘1 ss Ln 14 m" a : 4 j ‘ se | ~~ if dS eel : abd - = ~~ i 4 . fa% < ~ » ° : » \ ’ Z ; 1 . \\ x | aa ‘? i] i ‘a 4 ' to» ee f lo Sy ils Pi ve - = c Co ‘ by ° rr iq ry , a= 243 Between September 9, 1955 and February 16, 1956, five drift card cruises were made. On all but one the cards Showed at least an initial drift outside the bay, and on three cruises the surface waters from the outfall areas appeared to have been completely flushed either to the north or to the south. The one exception was the cruise of September 29, on which the cards moved toward shore but at relatively low velocities, generally requiring 48 hours or more to reach the beach. However, a single card from an outfall station on this cruise was reported 24 hours after its release at 1:30 p.m. The next card recovered was 46 hours after release. Anomalous cards of this kind appear not infrequently. It may be sus- pected that an error was made in recording the date when the card was filled out by the finder, but it should be remarked that in tabulating and discussing drift card results, all cards are taken at face value and none are omitted except those which obviously are impossible (recorded as being recovered two hours before they were released, etc.). The case under discussion is the only one in which a card from an outfall station has assumed such importance. If this card be elimi- nated, the minimum time of drift to the nearest beach would be about 34 instead of 19 hours. Beginning February 22, the situation changed and cards from outfall stations on all eight cruises between that date and August 9-10 came inshore with varying velocities. At first the maximum velocities were low, of the order of 2 miles per day, but they increased until on April 25 they were 6 miles per day and again on June 19 from the effluent station they 0.49 Off ts ceueler 892 Beste exon OS hetzoqet saw oahaws ee a eel ry) ye a i i . i} by ee £ *S _ * «a Aer i oa ‘ T i oe eee . | ee th) evil ,OtOL ~AD Wipezds4 bas 2201 -,¢ isdmetqs2. mss tem 4 «2 ebtso off ono tod ils nO .sbem a36w @enkuats b ipo SS3nt 80 Res ~Yae Wat Shéetuo ttixb Caisint ow teget +01 7 ot heraseqys efeas Lfeltvo sat mort e19tew sontawe sae as v1 oni of 40 APtam SAF oF asiit is hbodant} vletsiqmeos ase 2S 1sdwotqed Be C2201 oli exw nobtasoxs eno eat 4 wol vieovisals? $e Md atorie binwot bavom ebaao sae 9, d5393 of stom 26 savor 8) goitivpey ¥ilessmea 2oktk no woltsts Lip itwollee eet biso olfgnte - , wsvswoH -4288 suoismoaA .senstss 2993p atiod of 2nw DOTSPORES bisd x ava sd yom 1. % rok ie eta ede fi ' mo kas qent yd 3 izve- anit sth @0 fa. Die. djotew eupst sicanete ” od? anvenedW o /ARERs Jo quote saspkiingds s21t 88 zi tiiah Yo some VOQR TOV igin asqwisd =o0eR ' , , wo!) £ ,THOM Te . 30 4 tad! esteotint thre , : © f is‘ Lvoas fanciiinaie i221) of? % eomevhe ae teq 2dt.woetd Detataoigo 2. vod 24¢ Bolsa Oca oi) ot Qeofod feat sit ued Levbled taki te t Jei0qn »~it ta sien Sf aes aeth 9) 19 20% beghitpss asec »vedebi vow ton? r3 iny at} ted? gatewaen ,cr0de teaxnaa oad & bueo ott bet yiaqa Bibow beatweeted-~ cagsepqge Le s2ney ebb 4 «hued oft bse sie nyt aids ¥ Wee v2 245 ( ponut zuo09) yUTOd Yooy ¥TY 0} Bsoursdy uez}VeyUeW OF eoTUOW e1UeS Opuopsy OF Ady Tep ehketd Opunsss TT R BOTUOW ByueS *nqrrew Opun3es Ta 0} POTUOW eyURPS Opunsss Tq 02 uodueg esuedoy eSOWTON 3 Opunges Tg a nee €c-ee ACW eres Tidy lash Ovor 8c Yorew See | arse | ee -a2y jrxvoe | suo | x | ero] “ep o| ssw os j-suoo | su cy | s0-0| tro | -2u 09] -2u 4) 10) “FTT2D Bl eg ‘yorag ere sOY Yovog ooUeI IO], O1 ue4yzeYyUeW 2 Ea Se ee es eS a summyoa oul ceoe|._—_*d| ee Seek ee ep oT Sepreh SO1Vd| si Teel) 9G “een ee es a a a Ve EL ee a I x «| samyer ow cree | 8 |x | ep oe] sep gel moaausiuma| ce] CLLE Tid a ale OZSE 62 °3das ive) og) st - “OAV “UTW “SAY °xBW “OAV “UTW °TJJT PBpnTs esTtniy eToys 4sSaervsu yoraz (Hdw)--*- 3jTI1q SaTIaAO.DyY jo suotze1s 0} pertnbar suty ALTIOTSA jO SUT] uoT}eo0T Tedtoutrsg IIX FIdvL +2420 tatz. = .OvA iM.” — _. Pl yaa ws oe) ni) wee el x .it BS oo | “2k. 2b 8} aa St “oa “aged eausS acea ’ . E : OAR OUD. : ae A ten Sanae Se Sone «8a 8 ,ad Bb... Ay. |“ 61.0: seb SE | in §F ven Leb oeald =. ; } — / : = 024 i “ad BEE oad Pt | 2¢.04 @5.0 | .14 BS) .18 BS} of sattstinalé) -Bb af Vai oe > Ge 3 os sL3Sik ——— 4 ae , |} . -ESSE aoe)! ie vo lob at sist j : a ee i TT IIE — too ns : - nine Geer “6k A eet aD : =~ ef Ob i ~~ sd SF, } e> i -2F.o ¢ .¥8 St . Te CS} at Sieurgee in} EROS : acomrent iC t ? t bt i ee an NR ———— ——— ——— ee / - —— G [ 7, rr; 5 : ‘ae VELi : ac i | - 28-0" .7 4th +6 x 7 et. | of { rf seal : POD 8S totem { ; : 7 : i Es Ss i = ee eae Seer eT eee at oe ~s rae : } su sta £2 x- i i : : Li ; £204 | 4 pa Dats os ieee 4 — ———— 7 — ——s emo SS —— Se - = “ ~ ; i > s i AA j t 223% Bt ; #8f. of OR] ecinol Stimee .was ; Lies os E vs = s - > 2 / : obepes2 au 2 a —— ES — ae a aN e771 ee anh ; : Sf | $3.0 i? tH PSs yaa Isb sysit{; 80S4 : : ; ; , GODS Oo? ‘ i i. nn A a = —— —_ o- — nian se ng ee a Re IR — ow ~~ eee ear ae — ~ —_—_—-— — — —s. ra : an A 7 1 : = rs : = of a~ er eels «i Ti ‘6 Ve | re 1 bf an | ae : ic) ¥ 3 rol S Arta > = £ : | __agstadisM 03 : aT. F ra a tT 7 er ¢ P ¢ 5; i ; > i : (o. = . - Cdoeuntteco) 246 9C6T ‘Le °sny jo se ‘azetd -wo oUt SUIN{ION ue EYUEW 0} SoTUSA "aq 8p ueyy 1a ,eeI3 . | | LZOvViOC-6T °Sny z 4 i res] | OOSt| OT=6 °sny | SLPV |S 0} ueyQ eYyUeW | O17 ue. eyueW ‘Aad Tap PACT ELby Le-9e¢ Atel IO agpnts ou Zz ounft | Opuopoy | QO} ue 1eUUeLW ‘opunzes Tq °1u_ ve “24 eT £¢-0 cv’ oO “ay O€}| “AU BT| 0F bakit dated a pauee 80EV | a TTEv 6T eunf ° SAY °uTW ° SAY °xXeW ° SAY °TjJJX 8pnts astnig aIoYys }.SeIvau yore (HdW) ope SOTISAOISY jo suot}eis 0} pertnber owty AYTIOTOA jO owTy #wUoTtTzed.07T TedtoutTIag (penutzuos) TIX AIadVL °° ee oe ee MS it » < ' | ietessa fiat? .y_ —_ Ee ee so vVre: Var @ 5 velidorwg SAP at soMesitienle sonia (ioviveten tee sf , iy 2099089 8 @E .¥ tari: b sidt (SYR RRE Same ot! tw 22 NOLS TIE wbb ‘Liaever ef Shem 64a Bigous I2iS799d? £ De Beraset toc: notes tik yah io od; io obgm 3¢@ @ee eno ke >i ram foldw #eganfadsre 4 sluoitiray to 2 watt: gewoz to stunted wine to: fn? ytilidedow sdf Yo 2293y to voosed Yimgaraes Litw jnstin on ,Yovave Bi Yo =z "bbe to taslokitsom- 4a? oc sowot 6 VR oF Bes -2eie rotten i? £259n7¢ga0 HF 2 ijue 2nceakes esobiey nt tt ,79Vewal ,fed2i Woo Ss ete d is hb fang els B , fin Sisw 2aRe? by biz \tone si? brawe? yitagetaoh z ORF G2 ef dhe of TT een Donon AT s2B280 sat € be oe ¥ een ‘2nd estade ile e$QROL) new Ch i 2 A= \ (s oy > =e A. , of? oo ,eehawtTEb ybbe Vino bebesote #2 SOnma nolemvosib & taut yiqu iis seine) on feild ¥ siwees stoled shee a [USL 2OLaw © BE TORE ‘tives? of dasasaq OF) Ss) BAN eitzG edt cok > = ss ‘ted ho sogemonsia al reaver! tavdsod? AW nozinitb lesteyig. ie aoe si? ome bsoqm olonat £ol, ong tod ,otean sia} 008 s eswitoaothes to ae ‘tat 2200: ef? abe t tTartz2? ott gak ioiar miesdo oF obp a3 7 rkab waxt vttyves e22eosn smanosd df Tog agW maATQoT!W Od, 'o epaytaas yi aewh edateas emo e' ay * sl Jeb pee re iL 247 possible conditions using both maximum and "average" velo- cities. Whenever the time of drift was greater than about 4 days and the flow was out of the bay, no velocities were computed. It is believed that the reliability of the information presented here is good. It is true that the actual trajec- tories of individual cards is not known, but those which Showed the greatest velocities were, in nearly all cases, those which came most directly inshore. The distances travelled were measured along a line between the station and the points of recovery, and in those instances where the cards described an arc on their journey, or came inshore and were then carried to the south or north by a littoral current, some error therefore may be introduced. But whenever it appeared that the drift departed significantly from a straight line, a correction factor, arbitrary in each case to be sure, was applied. In short, every consideration was given so that the results, if they erred, would err on the side of increasing velocities. This approach is justified considering the pur- pose of the survey. Eddy Diffusion Sewage discharged into the ocean may be transported by currents, but its dilution with the passage of time can be accomplished only by turbulent mixing and by vertical and horizontal eddy diffusion. In Santa Monica Bay turbulent mixing due to convectional overturn (cooling or evaporation), or to stirring of the waters by strong winds occurs infrequently ' he 2 me tail ok fe! od f ' ’ hi a ; rl vn yy ; o-° “sosteve®” Doan temixem diod eatanr 200)7t bees’ ; 1 ; yi * tuods and? 07 p0RR aew +tivt to onl?. sav yavenadWelee siew #6) boefewvan ywad 243 to too. ¢aw wold) Say bee * yw ‘ J ‘cohiawr vo turk dt de yehlidsciio: oct Sat? Bovekiod ake “99Le22 Ieutoe, SAP GON? sexl vi 11, «Boog ah szsd Be (Coidw seokt Fuad yore foe > jo paeisk¥ises one at , lke ' vededso ight? bec Leitiak ey to thoes: tt r ~ t, ‘ i me Re pareont 9 ig BOWE? ‘SA? O22 iT B a inane ,*.% se 4h 8 ok? 90 ea ty ‘<2 A 7 : at eoltgwiketqqa fen’ : siomae? skid yasee ap tie pools eek! ogede Fo dtae ity ILed@sa0 ep ase aa lial fotdw sSeno vact ; ‘yen ,Sihsm o38W eoks® . , fownk eiat uegmalakb grol x zomtt gaol yidanceso%e 2BwW vise dog ery ac ja Sait : ft oF 82 roma gba ‘| zbxao to segm oth Dade Pativp . mie «oitexsneg 4% rsvocsd Sigua ge Lien: ts dosed ad? aoe } -Sigas stock’ S408 £3 st00e * begoeotqds 2biaS to i bigs iT. iis Ae ited) ap itiw rab 2ew bodton olqa wrow ody iwedane od Vika xu .w Sirens ted heote b t tas OED BO SEA 94) enokista dove shoke 22s tnt beavith® Samy ony * rye Yio Deus BA | love Io iowiot & bagotevah (7: ay ,arvorte sf? a . been ad nen : ; evticb The Fo tasksltisoo oc: 101 beteqmoo eee v | i x £,%0 of YOL 0 Sad> mort bogus aokiata tow bev et » F be ror « & neowred Yal eeolav beog ,Tavawol “a pluesy act ,BoR\, KD "or x (S.1 ssw sukey as Hh) 9 rtasvnt ontacgd bemtatdo ecodit diiw sastekeags,” t¢e 2.ce" vd Beerspenme, oxa dotdw 2 bottom 1H te va of vad ot ot & e6e) Bebtav f)ixh tov oe gots 23% bas aensiog Ye eaten reewted belioval ‘ seoten (as 250 In the twenty cases, there was no correlation between the value of the coefficient and either the time of travel or the distance travelled. This is not necessarily contrary to the known variation in the value of A with the scale of the phenomenon, but is simply means that within the limits of accuracy of these computations for A, and within the time or distance scales here involved, no correlation was apparent. Discussion and Conclusions The circulation of water within Santa Monica Bay is Maintained by a combination of many forces. Among then, not necessarily in order of their importance, are these: 1. General coastal circulation 2. Winds 35) lides 4. Waves 5. Local thermal conditions The influence of general coastal circulation certainly is feit within the bay, either as a general northerly or southerly current or perhaps as an eddy, the inshore portion of which may affect the direction and velocity of currents within a few miles of the beaches. Winds can establish currents either by direct frictional drag or indirectly by setting up density currents due to mass transport of less dense surface water away from, or toward, - the shore. Rotary currents in deeper water are associated with tides. Those closer to shore are oscillating currents, moving in and out of the bay or up and down the shore, changing direc- tion with each ebb and flow. 7 1) ; ni? i Lee eek Om er ee! ae) } a iy @ovlies aokteletzes oniesw o1587 .AdasR ¢toawd odd ey - (evext to Sk? ea totic bus teetoebiees edt Te: ou La vrasioo.s Yliresiegee faa #6 excl bollevasy sonetekb § siase 2Aag shite A te euvinv oft uti moktartiay woud, gi a Simi sald nahn JuHS enussa (lqmke ak Sed ion oied 40 omkt odd obtPewWi Son ,A to) euckisingmap sand? to Wal tas zacqs ssw aoteegiatgo> or vv lovak #298 agtene se y SHO Leb1sRe) hos col eavoekd si ¥ cf an kwolt adage ain) iw tew to aolisiveaprs ,nont anomA ,@8WReR Ynem 1 tTentdmo2 @ ¥a) ® | toned ove , Stost nogms szos abo ak ities ‘ + coitelwayto 7 o> Jexsase. af chokW .& obit ,& aovew s& Snes hiro 9 ot, Inoot 28 Yintstie2 colisinomeayEeteaes Cotsong to somoulink to yYiters 100 Qe2Geee es OS 2507) “vad od? “‘akdtiw » nolktioc e10tenk ot SORDe a6 2046796 Ww tee tno ok etusaiys to yiisedew Bie molrooih oft Poet iaaen sgodaned oft te asian wot os, wtrokst tooth eC) gees ttossies deiidatee) mas ebnew, + ond etooTsae Qeimeeh qe gakitee yo yi sosaehme ae btawot to ,so2) Walie tev son tied SBroh oaet) Ieee at itcu berersosca ore Gedew 29qSSD ah Wapato YreIoey Rem ivom ,sttro.7two aeblatlioeo #2 BaOHe OF IS80Le 2 7 : ye, \. itb gatasedo \stode ott pwol ieeuge a yal ama tena * coe a . 251 Over most of the bay waves, whether due to local winds or to swell coming from distant storm areas, will result in only a small net transport in their direction of progress, but inshore they play an important role in establishing a fitteral drift. There is some evidence that the large quantities of warm, fresh water introduced into the bay by the Hyperion disposal plant, Ballona Creek, and the two Edison Company steam plants may cause local modifications of flow. There are no data at present upon which these factors can be satisfactorily isolated and their relative importance determined, but we can deal with observational data which will show variations in net effects. Surface Film The behavior of surface films or of floating objects whose bulk lies largely above the surface of the water did not come within the scope of this survey. Neither did the collection of meteorological data upon which predictions of the behavior of such films from the region of the proposed outfalls can be made. The only statement possible is the general one that if an appreciable wind is present, surface films will be transported in the direction of the wind at a velocity greater than that of the water beneath. ‘During periods of relative calm or during periods of strong winds when the surface is broken by extensive white-caps, their drift will correspond more to that of the upper layers of water. oaat roams 2 Pa 4 (fim .eaoo0 wedge tanrebb-ans?) gpakwto Eke cq. De EP OSe ER 2 bos i Satoqens's? tan tiemas io ecoftsitneep spiel edi eho amon af Sz »nidekidetes ab vio tu: yak a Take your sxrom - | a, of Suh vatitadw ,sovew vad ORF Te Taos ITO: »t¥rabe sokreqvH 2A2 @doysd sis o sow bosdRk tet aw dastt yor.qreD noelhht ew? Sao bn: »32) apoliad, ,Teeig wolt te mm ftaat th & ol stiwao Yam stastel i szgTost eest? dori neq Tao*5: s ainb of Sim 9S AF ; a { doldw sish JenoisavaRedo ft: b nad @w Nod » OOme ib-404 14 lo sGgttaa sits rloyaat askit of eit bih yecdtish vowiwe piety io jonas sf9 atdtiw wot beaq daktw Pome wtel jlorxoaioa to Ae 920d 1 oi to sovkeea oe? mo icky dose to TORY. tt 2f oldiasod JeemRPRIe Yi ‘t Shae 90 fen: tt tnecene @b Bebe eldaicvsaqga ae VE ted? er” ? w ott to nolkyoweeh “et i botaogenaze soar tm .ttsescad eeewien? bo Tal? mad? 79testy “a vitales wiegh bese L- ak ¥litotoe tetige Jatoro sa dk Sool? site Woe mt £4 cttnol? Ye YO el wa tO sol veted > to pbokasq qaizes to atao pvitalor to. + ct? » > bow awkeraiad 9d amodotd ar sot all raqqe sf Yo. 2eadh ot rion ba oq ested DE ora J ema! = 252 Surface Currents The main focus of interest probably is in the upper layer of water because it is within this layer that a large part of the effluent and at least part of the sludge initially will be found. They will remain there until they become so diluted by settling of particulate matter and by vertical and horizontal mixing that the waters are no longer recognizable as containing material of sewage origin. It is also in this layer that maximum current velocities generally will be found. During the period ot September 8, 1955 through February 16, 1956, the pattern of surface flow was variable, but the bay appeared to be well flushed, at least intermittently, by relatively strong currents directed either to the north or to the south. Of the five cruises during this interval, on only one (September 29, 1955) was there a general drift to the east and inshore from part of the area. On one (September 8, 1955) the initial drift was to the north and outside the bay, and on the other three the surface waters appeared to have been removed almost completely from the bay (December 29, January 18, and February 16). Beginning on February 22, and extending through the cruise of August 9-10, 1956, the predominant drift was toward the shores of the bay, but frequently superimposed upon this was a moderate southerly or northerly component. Many of these later cruises, as well as the earlier one of September 29, 1955, showed signs of a divergence in the current as the water approached the shore. It is most clearly marked on the charts showing drift card returns of September 29, Area III, and of ready sditebh eke Ededio 4 Au’) tad sawel end? ne itiew akvia opheioa sab fe Ban ne geooed wet 02088 wiser Inntausyv 0 Ree Set ne (daricegozue7 tenmel Gm ox 1 ot obta =b aR paid yo} od thw ol Satanee) Oars savittet dogo? BSGk oh iescd ois jud .alds ita aaw welt wos Litwyedr EE tet! tetvesrsoe} Pe 1: $2 eatuaeded- 3976" 1a in bea tapvl?ts ott 3 nas o% 9 ttapq to gabisiae bi ¥ ce od? ose ga teem fade YT Yo lobtetaw goterags 7 Us eoitgo oomixam 3am bolLired’ sa? Re © 5 atettag odd .am i 4 noltiazeta® Peer ga 2 Dlew ad ot boing 19 Aron ot of seRtag he 21rd RooTtte WE v no no ,.favaotnt ebay grew. avil st? 30) /aae 0 stint teams a7 . 2e2Pl ef. andere 19% “ofa iaatqe2) snere® Re o 23att wort srxod bre vad eft ehihedego Ge alt i be PED iak® A ood event of Lexssqie wa of nw lage ef? geese? r9dtO . senna] PS yodmeagth) vad oA is otquoa’ rem eet viavadettl fy tpi LDS PRS Bev Lawident to griantg® wo im Titvh tapheRepss4 43 5605 Of" Jepawh ae rtd nogqu beeoqahsedne etehoupo:? red 1nd. wee a) 29301 pif tisangmer vitariyor 1 Tinga wte79hn PL yf rodmotew ‘to Sab woh htme Sit 4 Et ax “A jeontune A _ ry; eit vo teachers Qa BP GONVQIerTes « +o ie Bet ; = Hf y Dette Vigseolks Jee ee 27+ gape ont — Le : Ci soTtA OS aegadagee tenes ri dic ast rs hag Hee af hed ae oY (hel So 253 August 9-10, where returns from stations north of a parti- cular line were separated by an evident gap from those below the line. The cruise of August 19-20, 1955, with its strong northward component and low velocities suggest a return to conditions noted in the fall of 1955. The location of this divergence varied somewhat in position from north to south. Its distance from shore is difficult to estimate, but it usually extended at least to within three miles of shore. Whenever an inshore drift was well developed and a general southerly or northerly component was of no great importance, the divergence appeared to occupy a place generally near the center of the bay. If the spread of cards from individual stations be examined in detail, there is evidence of a littoral drift close to the shore. Occasionally this spread was greater than could be accounted for by either random dispersal or by the divergence described above, and cards appeared well to the south or to the north of the main group, the time of travel being not much greater. Such cards may well have been carried by a littoral drift in some cases opposite in direction to that of the main current pattern. The general inshore drift of surface currents in the spring and summer of 1956 has important implications as far as the transport of sewage is concerned. Certainly such a drift is less favorable than a situation in which the currents are directed offshore, because it means that material dis- charged from the proposed outfalls would have been carried shoreward. However, the direction of flow is not, in itself, yqunde oF bexesgca atmegzevtt oc! ,comatsogm’ Saeag 7 @itx6¢ « to ation aeahtate aor? anivt92 oxstiw: (Ot : woled oeont miatogdig taebivo as ve bos eaedee O20" sokt ghoris 29% Gthw yAROk (OS-°! sanwA Bo enters ome, Iwwios & SSBRRwe Cott toolovy wol has daagegmes t ’ 220! to tiak edi ak bsdon ni jadwomie Beataav eooos:ovib eid? te mektasor ai siod2 mart epgetetds 211 ‘tvos of dtseq mom ri yen, ot ten tn bo bare x4 Wilda Ts] r yud , siamited or 7) ; ese Tit s1sckank Qe Aeversch stooge lo aolim esaney 1 taenoqmoo ylrodi zon 326 yisedinc .78099 #.. baa beqelsvs ved eur Yeoretoos ott 190m eter 4 ed etoltate Lethhvihei mo1't «>ote9° to Sastge sist? fdinh Lexottel ss So somebiv syoht ,Linteb as se7eeTtn caw beowge BER PiLao Leo e1oda sit 6 so: Insuxvoqzth wohaae Fen» iot Detevonoas sduit ° tfow bexzasdan abxegl Bek sevocdso boditeasd sonspro ved. = | lo amit ett .quom @bemed? jo «?1on eff of 0 Aieomy BS . avend itow vem aibpad ase TURD ticem 7¢on anked 4 pe 4 ni otkeoqqo #5489 ORR BE Tiish Levees hiow ea eee asovteu #esx0> niae 30) 30 tad. oF sit wk etoss te ORR RERe Yo / lish erodgas tnasneg es ecotlsckiqak gaerseqn, | 00k Je 2pmmre me . se ftove vlaratteGel ORO TORO? = SaNee de Hroqenext 9% : ie fanwaago of2 Soltdw @b) Bei teurse w nei Mei oot ak # R ; at rs eit tniustem tadé S2heom ne yeuaoad Louda Ne hans 325 a as 20m ‘ae - Na Lee byiazes eed eved) biwow attalave Owtoee tay oad ee bani + jtieeti ne . ton ab wold te ce eetLe eet eae 254 the limiting factor. Given a shoreward transport, the rate of disappearance of coliform organisms then becomes the all-important criteria by which conditions at the beach must be judged. This intimately involves the velocity of trans- port. The general statement has been made that current velo- cities in Santa Monica Bay are relatively slow, but this is not sufficient. Because current velocities are of critical importance, it is necessary to analyze them in more detail. Current measurements involving the use of current meters, current crosses,and drogues have shown that outside of the littoral zone velocities of the order of 0.6 MPH are rare, those of the order of 0.4 are infrequent, and the usual velocity is 0.2 MPH or less. Current meter observations showed the highest velocities in the Malibu region and near the Redondo Submarine Canyon. Drogues have given values as high as 0.6 MPH in the general region of the proposed out- falls, but it is to be noted that these observations were of drift of a few hours, and the net transport toward the beach would probably have been at a lesser speed over a period of twelve hours or more. The maximum current velocity obtained from drift card recoveries was 0.78 MPH. However, of the 1,803 cards recovered to date, only those from two cruises showed velocities greater than 0.58 MPH, and the number of individual cards travelling at that speed were few indeed. On only 4 cruises were maximum velocities in excess of 0.31 MPH. Moreover, almost without exception those high velocities were obtained from stations De" a.) a icy Pe be, al) j Has - adr \?xodaietd baawsiode «6 werd odt eompnse meth jametasn 20 ato 1k leo fe 221s TOs eh VW jaum toned orl) Ree es bbnos aunt? Yo ¥ tion Paw sa? sovioves lev teex72o Bade Shem, ae: az 2td? tod ,wele eiewituien (scitixs to e328 BBkP Root ov ts -tketeb ovem a2, 6G? eny lace 2zotem tuez199 to 280 9a? arev! sbketve Same gwone sv ? o car ates 2181 218 HIM 6.0 to wehao laveq ont bite |. Sogipet ta: énotiavisedo se7am Feeate. t290 bas noiges 6de han Se) «i ao 2oulsev nevin Sven Seen rU -tro bsevgotd sat WO @orRes if sasw tlosed off baswo? Psogegete fo io, boizsq a 29v0 Deege geer tlisb mox) beateige iy avons: ebres £08. 0 eae to 127 aOoUD anidlovaext abseo Lamhe viiee umixnam eyow eseioco +) ¥iRe- (nO volute seouia ~2evoen04 v3“? ard dnamretazve tazemeg oie Yor pokaoM ataae \wry ieroosg odt ot BOM Slo arokiavyie¢do Seany tac: © ot sapyowall zetiioolay bewode emerers ow? mow), seodt ying, vst to MIM L£6.0) to ex9oRe! ak } benédatde soow seetagolery sii) Peres 2 gurke Hab, doidwi vd) skeet ewe reer latent tak abt wo Seegnoe -ra9hab as of yaseesoen Ok Pk at etnometaasom Jas on goxh bab 25eeos Ra o 2akttootee ones. ‘o &,.0, 320 29530, enaeme a9! so HIM SD abe ‘ eottisolor tagnned oft & io rand) onizamdes ohaodg ay on wdiod at th aeaiy i) tne -etwed wo) ss toi c to aged sve yidsdor - 910m, 30 savodil liev treovewo momkxap : 3% °> MIM 89.0 wow nok xO 7 bas HIM) 8%..0\M baba wel ate banana retin 983 255 lying in the southern or inshore stations. For the vast majority of cards a figure of 0.2 MPH is a reasonable average velocity. More important than the maximum velocities for special regions such as the southern end of the bay, are the data obtained from the stations located at the approximate sites of the proposed sludge and effluent outfalls. Reference is again made to Table XII, in which those data are summarized. In no case was a velocity greater than 0.58 MPH recorded from a sludge or effluent outfall station. The single case of a maximum velocity greater than 0.31 MPH was recorded from the effluent station on June 19, 1956. These figures are significant because the velocities represent the limits within which coliform organisms from primary effluent of the type found at Hyperion will be reduced to legal specifications at the beach. This matter is discussed in detail in the section of the report of the University of Southern California which deals with the bacteria, but the general conclusion is that under the conditions specified, the coliform standards as now established by the State Water Pollution Board probably will be met. The obvious question now arises, can velocities in excess of those described ever occur at the outfall stations in the central part of the bay? The answer must be in the affirmative. It seems reasonable that under conditions of strong westerly winds, and perhaps rarely under other circumstances, higher velocities may occur. None of our observations were made under storm conditions. Exactly how often this might occur, e besy oo oO» ehoddare ctodeak ao 2 eeeeos ody it) i wo oidedeasea ke Bh HIM 5.0 to one ghiie Shas ie Us aa soa2 rot wbbe¥ieotey mecivrcs 247 wedt PeetaOqMekss do ete ated quis Yo bao nuedives eas te dove oka op esttxoigge SRF Joa Desens! 2noktyse off) mor? | + sonotetod @tlateeo srov bee 2ehuis baeoqoxgis . wehysadeon ore pie egeme dolcw of , DIX oidsel of eae ul bab30D92 ae er S20 aut tolsorsy eTkoolev 2) sae 5 > a2 cin off mo kinye [inisoo teowlTte.c6 nybule € 49 ooo2 caw AGM) DELO ws ‘coug vrroolev momaay sayzukt szedt? yOROE GUE.aqvl co aoktare taoultie asvimt! od? Inseaxgesy Beidiooloy odt oeeaced) fussh Ties iY to tnowl tio VReReRg een? ee o10 mretites dokiweil el trortissqe trys] ee bbsrbe. »! .c aglzogyl te bagem ‘ eft of Lintol @E BeRepoeth co) vod oem) Veet - toned? h etwxotiiad w29di0o8 POS RRaTSVE 14 lo.tzeqe2 sith to ae tt dokevlogsos Lueeeee eee Gad .ot1otced! edt aete eleoba Bs iebnuete mxo Tiles SRR yBattiosqe anole stages ect soba [dadorq braof soétetio® gegaw ots e odd yd) bedaridatem 10 ‘ i ,?ou a j ro pt aairisolawemep peeaess won noLrregep evoivde oar rT t+ at anokreaté Cbgkeeo’ ei? tn ued0>o 14¥o ted nase Ss ey aerté idea o6¢ gk sO eee vowena off Syed ott Fe Jxsq- os fyetecw atorvds 16) eno r2eb008 1ee0r tna? oldeodeast @ | a) oo ke aint ssotptameorts wetie 2etne ¢Loun» eqadzeq Base : ite fia cre awiobtevsends a9 2b eho .9990 eR eae 256 in terms of percentage frequency, cannot be stated because there is too little basic information on the relationship between winds and currents in general, and in the relatively Shallow water of Santa Monica Bay in particular, by which a definite figure can be established. Deeper Currents The circulation in the deeper layers of the bay poses somewhat more of a problem. Current meter and drogue experi- ments seem to show that whenever an appreciable current is present the deeper water flows in the same general direction but with a substantially lower velocity. There is some indication from current meter data that deep currents may sometimes flow in a direction different than that of the surface layers, but this is by no means certain. When such differential flow was indicated the deeper currents usually were slow, less than 0.2 MPH, and so lay within the range where the current meters were inaccurate both with respect to direction and velocity. On purely argumentative and theore- tical grounds, it is not impossible that currents near the bottom in the deeper parts of the bay may depart somewhat from the direction of flow at the surface, and it is not at all unlikely that they may do so in regions of complicated topography such as the heads of the submarine canyons of f Redondo and Santa Monica. But over the bay as a whole there is no basis in fact for supposing that deeper currents may move out of the bay when the surface currents are directed toward shore. vyiovitelot 90% Ab tak \tarenen ak ao bat me ep doidw yd, sehwokotag of yok sdiholipine2 to x9t ow WO .bodelidatae ¢¢ os> Sickie gseoqg yad odd AO azeyat secood edt mt Botielworks @ -kxeqxs eugorh be r9TS9M QeaTiv]§ .mneidomwy s to stom: 2 ei tusi3s9 9 idatosrqae me rsvonenw Fads wore ot noe noktostib Lnzomep omae ofy mk ewolt 2edew. zaqesd shel i emoz ek srsd? Jighhgetev iswol yileitastadue’s ay van atroxit> gead deh? ateb «x2tom suszxD oT? nots efit to fads madd OMRSTILD sottoostb es me woth eam dowe nodW .aketaeo SNARE Or vd ci aka? tod ereyel 9 yifesew 2tasiiws 19qeeh OAT betsoi hak sew wort tehtaot ogan: of? nidtirw yah @@ tes , HIM &.0 pact) seat ole ot tosqzox dtiw sted SRRRWoReut 19" arotem tnextes Saay ro ~-100H% bas svitstasppgge Fiewsq: sO .¥3ivelsv bre mORF oft rset atnersws Heme Sidrescont som eb Ht .ebavo7g tsfwomoe tiseqsb yam Yao sts le eimeq asqesh od? mbm te Yon 2k 2: bes ,3ae2ame en? ta woit To nott0er2b ont bsisviiqmoo lo enpkget at oe ob yam Yom? Tens ¢iedi ti ito enovns>s sabaeagee ofr to abesdd ont an dove ea : scont sfodw s 2a°¢ed Sat te¥0" teh hes: stnse. bas ot betosskb sap! etepeaeo sostave | ot ed vad ont ye aee 9 ( it Fy f ‘Sup ils 2 +a Abs ny 257 The deeper circulation may be related to the divergence in surface current pattern which was found to exist in the central part of the bay. Whenever such a divergence exists, subsurface water must be brought to the surface. This might be reflected in lower surface temperatures or higher salinities in the region of divergence, but apparently the rate of up- welling in this area was so Slow that in view of the relative uniformity of temperature and salinity conditions normally found in the inshore area, and of the shallowness of the water, the presence of such deeper water was completely disguised. It was often true that whenever a thermocline existed offshore, a Similar marked temperature gradient was absent inshore, but because of the probable intensification of vertical mixing as one approaches the beach and the shoaling of the water, it cannot be concluded that the loss of a thermocline necessarily was due to the divergence and its accompanying upwelling. In short, there is no reason to assume that herein lies a neGhanian of sufficient velocity by which material from the bottom in the offshore areas, particularly those adjacent to the sludge out- fall, could by brought to the surface and inshore. SUMMARY Santa Monica Bay, a large crescent-shaped indenture of the coast, is in open communication with the ocean over the continental borderland of southern California,and the character- istics of the water in the bay are mainly controlled by the conditions farther from shore. Protected as they are by the offshore channel islands and the mountains to the north, the PQ TeVI OOF Oe Hatpies od y ast worialvoatig ssqgem oat, va ott at testo ot (bnuoty any dotiw atsip egestas soe -efakxe souogaewh® @ fore sx98vonad¥ ./, ved, sit, 80. 2ae0q) ae ‘ rdaim. ebdt -Jeoetawe af3 of tdovosd of feum ustaw een soitiniine 29a gid), 20) aeaheesoqa: cvs lige Towel mt tetoshe : in qe to ste: SS ebimezeqds +: iomey saves Jo aolgoam e ovitelor off 10 \webw ae Pad? wo | 2 pow Bere ebo? az (iisazou aco tte btee) OFank La is Mu s29qued- louyee i sotew edd to eeanwo ligt eat. ic eran stedamk saz 3 Hsetenerch vietolqtes gar 121 19ob dows to so aeee ,o1etietio bsoieéixo snifoonmeeny «a % cw tad? S27 astiogg tud ,orodent taosede Gav theibaxs ufaweqnet Sotism sa Bs ’ pe goixim Igo. t72V We M@APEDE* +: i: sidadesq aa) 3a th , retaw ott 20 sep twpene oc) ‘yned ef? sonssose® vituzezedean aniinemisdy & Fa. exe rod? bebe Lones. oda nl Hrllowge- ari eggepen. 47: fOATSVED oA? OF mztinndbom s ese rope DEG? smc 2487 On ch aneds we az az mottod ed? mote Beereren 4 v vd ¥?inotlsn tnekos ee ygbula of? of \Smegah ee or \ralwok?tad) .ensaR 5 ontenk hey goets: nt) of Styeord v¢ Bigeeas TRAMME! 2 to sagtaebur Dageaaeggedseons ser9) © » yet, AOROOM Eas B edy xsvo oeose e@tiuitiw netteotavans. sege ah ak eeeaee : vy otostaso ot? bes, eto tele atadinses to Sal sobre Iesneads . « ) if ¢d ballestaom inten sam Yad) oc7 ae 2oSe8 302 Yo) ack deff tt vd ean vom ea beroolows |; openeta aos t tad tay cps ae oft .ttior eddy of eain¢neda 686 Des elaaias isnssds ona Y ais a ae i ‘oes fn eere ai 1 i" 258 waters in the bay are generally calm with only light to moderate afternoon seas, and low short swells to disturb the surface. Rarely, winds of Force 5 or greater blow from the northwest causing rough water in the southern and central part of the bay, but leaving the protected northern portion still in a state of near-calm. A swell with a period longer than 10 seconds is rare. Destructive waves are, therefore, nearly unknown in the bay except in the vicinity of Redondo where the bottom topography causes extreme modifications of the wave trains in the surf zone. Current action in the waters is likewise gentle. It is established primarily by winds, and since they are usually of low velocity, the resulting wind drift and density currents are also slow. In the shallow nearshore area there is an oscillating motion due to the tides. Such tidal motion is normally parallel to the coast, but is frequently modified by density currents which also move in a north or south direction parallel to the eastern shores of the bay. Because the water moves slowly in and out of the bay and because the net motion is determined by the interaction of several different forces, complicated patterns of water structure result. The Shelf Water Mass, which exhibits characteristics of deeper water from over the continental borderland, is almost always capped nearshore by a warm low- Salinity water unit originating from the Hyperion outfall, . Ballona Creek, and the Edison Company power plant. At times, this unit may become so dominant that it establishes density Slopes and subsequent water motion over and above that normal 8? . a ij 7 —_ - @ 9) rdeli efao at iw also vilaxceoe one vad ada aie 3 davieth of Affews trod: wo! bas) ensapneéarest tare BT no2% wold 2608898 ge 0¢ ea210% tc, 2baiw syisian $08 tae Letina bets nxreeaen Soy ai 1976w davos,-grteuss: teomtsaan nok fT toq int ocd 2a fetoetorq of? voivesl aud: wed sage Ls seol bori0q # Agee LLewe / [somngen to state gg an A ' “Io loiedtt .stedevaw evi | Vote 2t etdooss Eva a, ' ; ae obitobal Jo vitrmioky eg? nt tc sd alt of nwoming ib 5 it} io enoltects iba siesta 20a: dqstRoqo? mot tod omg . . : is ie O8F ME Satges a ek 71. .eltest spéwatat ef 2: i? at aottos tneaae 7 7 } to Vilsuev ese 19dt Soeee baz iw yOu Lbanaibeq: beg etasuso yticoeb bee PEERS bn: ‘tines edt 4vtiookh os 2h sxed+ so1@ S7eneteec wo lL. efi al jwoleid ht nokhtam ([ebid wee Paehiy «: +S anb nobtom nite bsitibow vlineepsee Me ged . ifs if of Latligzasaq vee , dtvoe 10 dts08 8 RE avon cw atassiuo viiees ad + Jo esven ese: ; o> telistaq aokge ¥sd sdt ic tod Bae eiwo | ve stew sif sauvenae nolstonzsin£ onF en hom t wads sl vokion ten oad? edged ‘ sotsw to en1377eq@ SORRER Ramo , 200107 jnoxeTikb 1s73ee etididus da bie RGR TetaW tled= only .2 twas sw 9 sinenkinos stieeewa Meek 22iaw. 12q96b' te 2oitetrsyae , “wok Weew ¢ VO @OtMigeiee Seggey avyerian caenia at , baaktel ’ / f al ay ' ‘ ‘ ‘A tue cotsoagyl ond mia? cettdaeciaise” 3 icp sotew ys ae . yf — + rpamis ¢f tesla eeeéq yanqadD epe|etts ef), bie jdasasd > (itaesh avcetidedas bh Tant tekeimaed oe smoved yamE has 2 is ge Mee [narran fect svode Bas. tsve metiem Teeean Jaoupaating as <) 9 , 7 e > U om Ae rvs oe a7 — = 259 to the shelf water. Under such conditions a rather strong flow to the north along the coast is apparent. Other water units with colder or warmer temperatures, but with normal Salinities occur at intervals in various parts of the bay and are related to minor complex patterns of currents. Some of these patterns recur with a frequency that can be correlated with weather conditions on a seasonal or non-seasonal basis. Others represent single isolated instances of unusual reactions by the water to weather and tidal conditions that happened to occur concurrently. Because the patterns of water units are complex, as are the resultant currents, prediction of water motion under a given set of conditions is still somewhat hazardous with the data at hand. However, the currents are by no means erratic and the net motion over a period of several days can be forecast with a reasonable degree of accuracy. Water Temperature Thermoclines and substantial temperature differences between the surface and bottom water were best developed during the summer. These temperature conditions are most favorable for the suppression of the effluent below the sur- face, although even then the rising sewage may reach the surface. Inversions were characteristically present in the boil. area, indicating the turbulent nature of the rising effluent column. Inversions were also encountered in both the southern and northern reaches of the bay where upward displacement of vee Ah at2 sedted &B snektibmo> dove sot -19tsw Ms : of we agate 1stew 21990 vineteqge 2 tccoo of? gnole dzxem) ipmion dtiet ted jeettarccoot ts8raw 10° 19bLo9) tk vad ot to @iaeq aboiazey oi elavretak ta 20990 eorts ray smo2 .eteetawd Ie @anetiaq « 9d Hao Teas Yomeupes' + dtiw 2997, efissitaq tiesG Lencesee-nOR Wa Ignoesse a 0 anoktitaos rodtam enottose1 Laneunw to egonetent tetatoek signute tronsxqen | 7 ot bemedgsil tad? em@hgitmod Iehit box redtsew O7 1stew s Sin etinw “Sstaw %6 anrettad eft couace® .yitneszxo0¢ aetsw io notioiberg yadeeraus tcsilvees oft ots 28 eae tedwemoe ILkte Bk @apddi bao > to tse navig & zebag #8 sis etesztav> oft \aeWoWOH .Sosct ts adab ed? atiw 6 te boixeq s a9ve @6ktom ten oni bas ofte279 Shae fo eszpeb cidsnoshee B dikw tesco702 9d ago eynd. | eisaepzeq@et ss! 2sonsietiib owteasgmet Latinas sdve bas aloe beqaleveb tead oso 19 T8W motiod bas oon iwe ad? d teom ste anoltibaog gts: ou: ) saenT ,x9cmme ‘seam L ~ise af? woled sagw Otte ef) to aolaeendgae ogg 63 ae edt dosot (oo Spewed Ybets fit oot? asve squods te, A's Liad oft ak tueeoaag ss NSS axptltwos sat dtod ak beistavooke oale oteyw eno: to tromeasiqatb .biswqg, ay Yad. ant at ae 260 subsurface water commonly occurs. These latter inversions do not reflect any essential instability of the water column. Water Masses and Units The water in the bay has been classified according to temperature salinity relationships as follows: Shelf Water Mass - 48° to 73°F, 33.0 to 33.5 o/oo Surface Water Unit - 48° to 73°F, 33.0 to 33.5 o/oo Subunit 1 - 60° to 62°F, 33.5 o/oo Subunit 2 - 64° to 66°F, 33.5 o/oo Sewage Field Subunit - 75° to 58°F, 0 to 33.4 o/oo Intermediate Subunit - 54° to 57°F, 0 to 33.5 o/oo Subsurface Water Unit - 53°F, 33.5 o/oo Slope Water Mass - 46° to 50°F, 33.6 to 34.3 o/foo Basin Water Mass - 43°F, 34.3 o/oo The seasonal distribution of the various water units shows a biannual variation. The nearshore waters are normally colder than offshore waters in the winter season, November through May, and warmer in the summer, June through October. More or less steady state conditions exist along the Malibu and Palos Verdes coasts. Here cool water is adjacent to shore through- out the year. The conspicuous area of cold water along the Malibu coast is due either to a vertical displacement of iso- therms following a period in which warm surface water is removed from the coast by westerly winds, or to active up- welling. The cold area to the south is due either to an upward displacement of cool water near the coast associated with the presence of a southerly current in that area, or to Os ; i" age lesevins vattel swad? .2:v95%0 eloomed BeTswleas 7 gmnulod totawW SHR 9a yeiitidatent Letianeeo yas josfter ati? bre eveesh 19d BW ot yottrooge Bekigsegt> aood san Veded? mi tetaw onT 7 ewe Lo? én egidvenckiaion yi saeioe cists colo 2. CROP GLEE VASES of [8b =) eee gezew bea. e ooo Sift oF ORR GHP es os ria rotaw sos tee PONG BLOG | tSo oc 900 4 L siawdaz oole Beh yA de of ChO =) S Phaodwe OON® PLE of O (~RPRBaereey } fincdse brett snawed eo\o BEL oF 0 AOR $s Oh - sinvdut etek bemrasal oo\o BLEE QAPEt - sin taheW sontosedae cole £L BE Ge RURE yaeot of 5% = Beat’ vera sqonea ove f. 06 ,7°°) =~ 228M a93en are swotis ettay istee seokvav/ em? Yo col tvudiatéib Ignoaase & rebfLoo ¢ilamion #28 @eetaw Baetes: onr nett abaad ounsae igo xit ssdmevenw .meMAae wins wt #k eretaw oxode tio 1¢@ s2oM «6. rsdo}00 AgQUerne Savy roms aa ae yomTaW bas solsY bee ditem eet paéie tetx: cacktihaos stage rhsotel -fiquoad? stod2 oF PeseBL RA B2 totraw foods sitet 2428802 - ¥ eft paola rst aWw REGS te S828 ¢vouosigeneo eff ,Tasy * if i io Snensoelyekh EAOETUSV 2 of sort he ob 82 Beage eh i ystew sou Tmyel axe mointw of boizeg a gabwollot® “pr ovitos of 26 yaboiw eineiiaw yootracs | sar mom bevom os of tottio oul eb Mtuos 643 of abt bien ott na tis ietaiwoees teaod ett team eedew 1660 Pe ‘xemesuniaaa is Wie as 30 rca Tact ab daouxva yttedtacs @ 2 poeszone ont hh if 261 the intrusion of cold water from deeper levels caused by the passage of tidal currents over a shallow bottom of complicated submarine topography. The sewage field determined from temperature distribution is embodied in a large unit of slightly diluted sea water varying in thickness from 5 to 20 feet and covering an area of from 10 to 20 square miles. However, it should be remarked that the field thus determined by refined methods is con- siderably larger than that detectable by visual observation or by other qualitative standards. Temperature and the Rising Effluent The effective heat contributed to the bay from man-made sources is now 3.9% of the total amount in summer and 10.7% in winter. These figures will rise to 10.7% and 18.7%, res- pectively, when installations that are now being planned are placed in operation. Most of the sea water for initial mixing with effluent from the existing outfall is derived from layers at or near the bottom. Thus, considering the annual range of bottom temperatures and the spread between the bottom and the sur- face waters, both sludge and effluent will rise to the surface aS visible boils when normal winter temperature conditions exist. In summer, due to the greater temperature differential between bottom and surface, they may sometimes be at least . partly suppressed. aie 3 2002 Blew.) ote: not t TSF a BLOF a Fay ont. "TX as beats o> Linch » ST S| We «VOQR EROQST oak iy jixnturh om epee? os “uoteh biest Ssaswee retew eve, DOtRRER WLo duets * it ogxek « of 5OtOOGRs 6 Os ve eves ata Tony | * ave? brewed eo bevounmay 30 bi aewe Pa eseve ‘etre See Se OF Ox net Bt Lend dan Syedy k 3 , ¥ ; wrereb omy f tet? se oOtCPaAVySSstk meee e yo aiCe7 sik nedd Genabl we ~ LA Pig ey}. tatilaup Taste on a ,_™- ri Tm Rite CoN “iy ,a% a w a “Ws F ' “eo? Hetty ee (Kt09779 Bm ; PCO tee comin ib Pema |, iy ©. wom af et be: A! ;f dng Wh ae ees med $2 “tT ~ a joo pak tates ott | . re ari i i becoad wo tT Ao 3 FOS i i to Fe 219V 8s Ot koyr i La ft To. ORMMT Teun et i Dre mer reg bad spain righ oi0S brs 2a tues j inne ent a, ke 2 itde Paes ts. one tboefa fed ,&roce tr bros > ie eeene? idtniw lantd4 pedw elled otdial ‘Yih Sta eget 0 ReweaR eal of wu ey 1 TD enw nd a od adatd setoe’ yell Hem pede loos bos mortod a ‘i de 262 Water Temperature and Related Motion On the assumption that density currents can exist in Shallow water as well as in the open ocean, an attempt is made to develop a qualitative method by which at least the general patterns of flow can be derived from horizontal temperature distributions in Santa Monica Bay. A general correspendence existed between the drift of drogues and the current directions deduced from the slopes of isothermal surfaces. In general, the flow from thermal slopes was toward the south during the winter period, and to the north during the summer. This is correlated with the annual cycle of wind conditions. Water Salinity and Nutrients The salinity of the water is essentially uniform (33.5 o/oo) from a depth of 40 feet down to the approximate break in slope (300 feet) at the outer edge of the shelf. In the surface layer, above 40 feet, salinities almost never rise above 33.7 ofoo, and usually lie between 33.55 o/oo and 33.60 o/oo. Salinities lower than 33.50 o/oo are found in the region of the Hyperion outfall, Ballona Creek, and the mouths of small canyons leading from the Santa Monica Mountains. There is no signifi- cant seasonal variation in salinity. Average dilutions of effluent from the surface boil at Orange County and Hyperion range from 15 to 30 parts of sea water to one part effluent. At Whites Point the average dilution is 1:50. In the summer months, the limits of the Os ° nolt0OM bedeled time ow isr9qneT 79308 i i \ 7 ’ “1 wk 2¢ix¢ okd ateewee> viieneb tad}? gokiquigen sade noe et iqwette me yARgo0 osgo lt al esc ifew a4 29TaW we " sdt tesel $e oid yd bedisa sviletiiaep #6) dolores 7 ietanon tied bent beviecs>.«d 159 wel? We geretT isda Is ieuroy A ae pakion sicat cb smoktd@iateth ozgea * bus asupoih 20 FIFBS ost: wiet betaine sonsbas | Insrisatoei te esdode Sd? Ment Laovbeb exottoents 9958 aew acqole Eemerem? Mert wel) sit ,Lazeneg at, seem dtxon sdt of due ,bokss@ aetuiw oct ankaeb digo ot | ; sfovo [evans oft &0 be BehALozs oc eheat. - tee saz on .enokti bao. &inei se Mie YTiwilae seesaw Coo\o 2.££). mrotine yilatiaeeae ef x59 it 6 vFkeiket 5 egele at dAsont stamixowgyeeee? 0! «. tso7 0A Yo stqeb ‘ Sogizne sit ak . Finney 3 be as%ee sd? te ($9087 ; . i e fs 5 -svods oait 29v¥en JHORER euvtiiotios ,dee7 0% s¥oda ies D r .oo\o UG. Rb bos o@\0 22, Sk teens od olf yi laway bas Geum at ‘ ) : a sit to nolgex sit aE Bitte? Ste oo\c G2.0t ment tewel aol tha » eovttes Ifeme to ad¥wom ed? GH ,to°.> snetinph , lisiive none ' i ve -f3inyia om et e19e® ventethbe’ solaom wtrs2 odt mond Smee 1 } ry i. ¢f#imilsce ct goktebiov fesossom si : fe Te | - tr Liod sosiwwe sae most Pepe btis Yo eae eh ae 7 hig ase to #t1nq OF Gy EE moa) sgane Ok TSqVH hate ot oad _— eqeisve oft tniot eerie th wient die Di | one of 392 ot to atimit ont ,enf¥aom panmee sis nti Red, e A yA at 7) re) : A a» Pay. - 263 sewage field dilutions of 1:300 are more easily determined from salinity data than from temperature because the tem- perature of the effluent is nearly that of the surface layers in the bay. The nutrient salts, in concentrations much greater than that normally found in shelf water, were confined to an area within a few thousand feet of the Hyperion outfall. The small pockets of high concentration were distributed erratically throughout the effluent field. Variations in nutrient concentrations between the Orange County, Whites Point, and Hyperion outfalls are believed to result from differences in the character of the effluent discharged. Oxygen concentrations in the vicinity of the outfall indicate no serious areas of oxygen depletion during the time of the survey. Transparency The transparency of the water in Santa Monica Bay is controlled partly by plankton, but primarily by the amount of detrital debris contributed from the mountains, hills, and low coastal plains bordering the bay. Rocks in the mountains and hills are mainly fine-grained loosely consolidated shales and sandstones so that material eroded from them and carried to the bay during infrequent rains is usually in the clay to fine sand particle range. The resultant turbidity in the waters within a mile of shore is normally high and the transparency subsequently is lower than desirable from an aesthetic point of view. During the summer and fall a relatively high turbidity is maintained by wave action. The bare .@Llin ,asietawen sui @pst bs )lvdkititos st3d90 teshast antetawomw sit ck foe! ged sit snisrebred ansalq Tete volese tetebiloenes wistook Govies,-ont? yiatam Sam aes H Wf , cid nh. - 7 My ig wid Wy ai hi mserot tikeee cs0m ote 90525 Yo anokeel ib brisk? 4 iW cot of waeened savtevsamet mort! asd? ste Pte 01a eosiaue S&F Yo tart yix)esn #&) taseitte edt Yo acu: t v4 enoltertassmey kh petiee inci17en 9eT .ved eat Eee Ai’ stow ytorew Viete mh bevel vi (orton, Seay neat 2eFeere adit to *oee besepoers? wol « afasiw O78 ne of 7 nokteryioe.a09 Mee We eieatoog sive OAT i ftattao nok . bf aki tooult?s (ene Vimo? i {ao bP 23 tS baveeeanal i? if ; ‘ J : Ae anes) any oyews 6G BRodts 1) mod tneiaten ak sack ' os boveited sie #bletiwe moixs:!i one y raked 2ottaw a snowlite edt to sePSeteas oA? «i 2 mets TIES mom? rt adit to ytkntoiv ed? nh Resi en1t nese ave bag ted wniiwh noiroiqed CSyYRO FO Beets “sol Tss on otaot tak yoviue et 10 Omg « YRS tAGene | a a ee ak ys noimoM stasé GE wetew =i to yYoustegenaay sae ss - tnooms oft yd viivemiag Fed .acvinsiq ya yivaag bette x. as \ } i ill bek33740) dns oes? ment bathers [sixrsvies ted? o2 Bahotet wr "ots eit of Wibgtem @2 @itar ya pupsa tak gaiwwb vad hates ¥sibidxe7 toes inews si! ane oheii1eq basa sail ot bra dgit ¥ikembot ab stode to ot im s mada iw anata ie ry my Ma? tn mon? sidaatesh nett towod 2s yi toowpoade Ys ipl, 13 itet Sew tame, SAP Qube \wotv Fo takog: h ‘ae eit wngstde, vaw vd bliin ii 2 ai atria pti a i " Pon tid Le gts ee caTY a an yr 264 depth to which a Secchi disc can be read in these waters is usually less than 15 feet. With increasing distance from shore the amount and size of detrital fragments in the water naturally decreases. A consequent increase in transparency occurs until at a distance of 10 to 12 miles from shore an average transparency of 30 to 40 feet exists. As the sewage boil over the outlet of the Hyperion out- fall is approached, a continuous decrease in transparency occurs until in the boil itself, a Secchi disc can often be seen no deeper than one foot. For a distance of about two miles around the outfall, the transparency is normally less than 10 feet. Such a condition would, of course, be relieved if the outfall were removed, but the increase in transparency would be no more than 5 feet except under the most unusual conditions, due to the natural turbidity of the inshore water. Circulation of Santa Monica Bay The currents in Santa Monica Bay were measured by current meters, drogues, and drift cards. Current velocities were generally low. With current meters, the maximum velocity measured was 0.45 MPH, but most were less than 0.25 MPH. Drogues were used to measure subsurface currents at depths of from 15 to 90 feet. Velocities were somewhat greater than those observed with current meters or drift cards, at 15 feet varying between 0.17 and 1.07 MPH. At greater depths velocities were lower than near the surface; between 0.17 and 0.46 MPH at depths of 75 to 90 feet. There was no significant difference in direction of flow between 15 feet and deeper level. Bw i poet abe GAkenetont « en? ee earHea ams ra Dee fe 1 META TY oe a cad jane Pee SO py ea 7 t Pov peter Wee t ) os jet ee ed oe cy. et en ea rtf Seater Geet ot ose 70 Partya » Senqane 2d y RD SS) 1woda Mt aes wted ‘(eee Tae ‘odd 18s Lely | Vee, raw paper A Saw Sie nevh EXSaer « oanetehb. A 904 “rp ee nk oaths: U Set Ree 7 eo te en zi y+: Tie FEaos ty WS Rapa 2 Ctio aaNet eee ma 2a" gta 5 bo pe aetna ly guard LP ae ty 4 yedaneyy> we Tavanuny Tao Ttetaw sTonars ys 12 Fk ‘a. Ore ‘y6wW Aor t ton YI EAOLOY 7 me MM eh. 5 reat iz iw i hte I Rl ray + ei it yew eet a] ae ROSE, wate Fe: ow 2SttiooLt ov tA. oN SOU deme 54.0 neowrad why samy 4987 si ab ig, tant ef esta seek ee OM toed) ak song pees Cae a Do diet Teo basen OF bree Seay ronyoTd b Lh hit oih ties ath ttboo@ a donde on a o *nke. bas) tawoes eh wera sy A ,zaeasotoeh Vis somatekh @ #2 ce + Gelato yonora genes) al vo Liod wiewee oda 109 #: , batososqaeee | Pe '; Liod edt 2k Leeeee »} oto sedd -seqeed 6m i) ,~Sigtteo oe bane teil ha bao Ou tare. mrs omen sow Dla tool ae roo) 2) medy) orem On Ste a ody et sob ,enoke wy “ 8 LG QE? A ¢ ’ ‘léizth fore (oonrgesb eae , fe tooagwo OFEW!: .wolpwide : LB’ rud HOM @*.0) Sen eam 1 O8 pt Zh iweRte ae i) _ qu 9 hee Yio 8 ae veod? 265 On fourteen cruises in the bay, between September 9, 1955 and August 21, 1956, 5,326 drift cards were released, of which 34% were recovered. Included in the patterns were stations near the terminals of the proposed sludge and effluent outfalls. During the period of September 8, 1955 through February 16, 1956, the pattern of surface flow was variable, but the bay appeared to be well flushed, at least intermittently, by relatively strong currents directed either to the north or to the south. Of the five cruises during this interval, on only one (September 29, 1955) was there a general drift to the east and inshore from part of the area. On one (September 8, 1955) the initial drift was to the north and outside the bay, and on the other three the surface waters appeared to have been removed almost completely from the bay (December 29, January 18, and February 16). Beginning on February 22, and extending through the cruise of August 9-10, 1956, the predominant drift was toward the shores of the bay, but frequently superimposed upon this was a moderate southerly or northerly component. Many of these later cruises, aS well as the earlier one of September 29, 1955, showed signs of a divergence in the current as the water approached the shore. It is most clearly marked on the charts showing drift card returns of September 29, Area III and of August 9-10, where returns from stations north of a particular line were separated by an evident gap from those below the. line. The cruise of August 19-20, 1955, with its strong north- ward component and low velocities suggests a return to con- ditions noted in the fall of 1955. Ceyvz * rodine Mises teow! Tw Hotdw Va, bodaeatorietey 2h: ito £7 49 a3 3oW SaaS Na ¢ Us oes) y to enna: $n br LBs SOG L Lee he PAG oe — WOrtes . 8) wot iucd vitae stim yeted deeel 24 “eo dtsen edo. of Oped S. Doton- t ° a “' ra) a a 1930 eeht gakueh ene2:: thish Lax saopies (CORRE? tow 190ins? oe] iT ng - &978 Ste, ts) oitetue box ttred. aay) os St oft Dbo2seqqs #29tew gon Tue Of 4odmane0) yed off moat vierte exturs oft duverwd? akkbaetee Ors edi Biswas a2aW # Dia 8 ARE er > vie! perenne umeeo ye. 3 3 snc 38. TROTTE eeue Ll Ee SR! 29am Ty sc Lise A* “Siew 3c ome vu: sit Ao pay emey bhasets Pag! Puri i : y BA : A ,2S coins 1gS< coiwotited & to dtm taditeie wea: cnmiwepessde) sOieO era ; hd , ped sft+ woled eeodt wet) qen tirehi vs, ca 0 SStatagge oy ie =f + ee mtv Tes OOCt to Lint ode "a art cgi Ue OE oa *eCmo7g | ae rsd ont ck spehend) #S0oamo?) Be ‘ie OSEé /% ,orel sis Jarry : ir th bobo toa obo s¥ese> sage 2 to hokesq odd gatiag Jin us lise Qo ntrettaqg edt otme ‘ y! bie nael? Lise sive Ls ta sgge vogs besegtireg@E yiievrpsst god. vad gas to es » aro7te ath dt kw yteeh yOGeee seogns ict —2RUed att) i ; Pe respume Sssivioaior wol Dae Faw ‘ 5 d 7 1 ar f(t Val See Be q udt: Wo etenkeset a ie hi i LsnoTvweo phewte vistas : hy wowed’ ett 20. ees ‘L y@S 2zidmetqea) mod #4oreade baa F ~~ f *® 5 th1B Lnitink sat Chem dPiedte sat oo bee! jconie bSevomp) ASaam irantde. bow ,~8l ‘2 zi vyage2dst ne yniankgod , aty ,Ot0L 01-8178 © a@ yliedjvoe sta788 on Liow es -2e2iu19/% 1 4 ccoptewkb » To engia fae ‘2 lLédede eff bondomst ssutdeo titag ftinto yee A | ob F Mr Pe. pre fen ‘ ar hate ish! | Pil { Lone? 266 From all sources of information on surface currents, it can be stated that outside the littoral zone velocities of greater than 0.6 MPH are rare, those of the order of 0.4 MPH are infrequent, and usual velocities are 0.3 MPH or less. Maximum velocities are usually found in the southern inshore portion of the bay. More important than the maximum velocities for special regions such as the southern end of the bay, are the data obtained from the stations located at the approximate sites of the proposed sludge and effluent outfalls. In no case was a velocity greater than 0.58 MPH recorded from a sludge or effluent outfall station. The single case of a maximum velocity greater than 0.31 MPH was recorded from the effluent station on June 19, 1956. These figures are significant because the velocities represent the limits within which coli- form organisms from primary effluent of the type found at Hyperion will be reduced to legal specifications at the beach. This matter is discussed in detail in the section of the report of the University of Southern California which deals with the bacteria, but the general conclusion is that under the conditions specified, the coliform standards as now established by the State Water Pollution Board probably will be met. Velocities in excess of those values will occur in the central part of the bay, but it is believed that the frequency of such rapid flow will certainly be less than 20%. is PAS a nm i } ey bn if all: i, fa iat oe & ; fl ai =I ne ony . figs y x oo ow a he aoitamno ttt nyoINOR its? , en: | ‘s aeivioolow geet Temog iil ent site tee raatt bot ate es to shin, epi peodt , ox" eq HOM 0.0 padt setae ade inl ay" aN ) erp Beeersolsy Lecren bam Shee pepe “witues. elt db Rawat ¢llsvas Sie & sttivoley wmrinke "i ; : \ ian to vadodd ho motdaoqe yode 3OL aed fino tey Pract dK at igs rns Yaoqat o19M pint: sels » (ve SAF Flo & uiaittooe sit an dowe ne oes) oi me sy SHRdR ‘boisooi endtdete std mond Bam eeen on nl 5a Phettue) sas | ban guiete deaeqomgig Key oR Be nox Bebsooea Ha * itact ee bi ee mio to pane. Hig nokiate Ltstvee ra rns it mort hbebaeses, aiw ' Omarlt 19¢2407y VOR . a 4nsoktianie oc BORMEET Beit: of ,0L sas mo Bex ~kioo dotiw atditiw @2kmbt ear We 1% gettzooler ofr s fa be yet oath teetamneaet 31: salrg mor? emséinegiey foesd oft ta eno ktnod teenage tan! woh: od Likw none \ ; -~ sit: to nolYooe edt Ab fats: raaavsech 8k aottam i: | | i afesb dokdiw cine telsao grein vihevowkal! off LO i | aun tobms tadt 2s negBeDoNOm Pavers d+ tud ,abystsso° saag eon 2s ebvabmete aothinc bal iinoqe eno lst baom ‘) ’ a liw yidadorq bree mest te lied 127 eV otete odt yd bad Idi . af ‘ 7 ‘3 tou ly haat | " hl ie eer lav sands Yo eno pa myyns sshatbons “a ay : ipaat weds salt bawedk tod wh #2. bus ved on? to, aaa BIG eA POS wads Beet so vidtariee tt br welt a ~ mer 1 i - i my, i" Ler : | al : : okey 267 Deeper currents in the bay flow generally in the same direction as the surface currents, but at a lower velocity. This conclusion may not hold in special regions of complicated bottom topography, but it will apply to the waters over most of the shelf. There appears to be no mechanism by which deep water can be continuously brought to the surface with any appreciable speed. “Taras We oe taom zswo e v9?aW ef of vlqis Sliw 92 Sed ,yeqeagoger geeb doldw yd makesisem on od of erseqqs suedtt .tieds vhs ttiw sontaire @67 of tdsvoid vlevouniingo ad aad, ,basqe ofdadt 268 REFERENCES CITED Emery, K. O., 1954, Transparency of Water off Southern California, Am. Geophysical Un, Trans. Knudsen, M., 1901, Hydrographical Tables, G. E. C. Gad, Copenhagen McEwen, G. F., 1950, A Statistical Model of Instantaneous Point and Disc Sources with Applications to Oceanographic Observations, Trans. Am. Geo. Un., Vol 31, No. 1 Pearson, E, A,, 1955, An Investigation of the Efficacy of Submarine Outfall Disposal of Sewage Sludge, for the State Water Pollution Control Board, State of California Stevenson, R. E. and D. S. Gorsline, 1956, A Shoreward Movement of Subsurface Cool Water, Trans. Am. Geo. Un. (in press). ~~ ae toe ‘ ina hit ha Br aeeiad ey