Yor. 7 We | " DEPARTMENT OF THE ARMY CORPS OF ENGINEERS THE BULLETIN / OF THE BEACH EROSION BOARD OFFICE, CHIEF OF ENGINEERS WASHINGTON, D.C. VOL. 7 JANUARY 1, 1953 NO. 1 TABLE OF CONTENTS Longshore and Coastal Currents at Scripps IbaSwalitmenieia PSE 4 6500000000000000000000000000 Charts and Tables for Determining Surface Stone Sizes for Rubble Mound Structures in Wave Action ........ Japanese Research in Physical Oceanography, 1948-1950 eeeeeeeeoevoeeeeeveeeeeseevreveeeeveeecveee 8 Progress reports on Research Sponsored by the BeachBHELOSTOnwS Oa dirrlelelehedehelonchenellelahelsiolehelelelelekels Beach Erosion Studies escoseneveveeeeeonesvsevesee se VOles ( JANUARY 1, 1953 wn 0 03 | nT l NIN 10 26 36 47 NO. 1 iy a we f ah FG easy oe by pe We at ee Reig gh enes eck aS iy { ee ar ‘vg QUT pu alr i CDE ERR ee Meme We ey gy wp i a Baers . F aah 1 BUEN Bee ig aye) Pee ee OEls a> , nt th VE FMR Rie eee ws eS ie fi } LONGSHORE AND COASTAL CURRENTS AT SCRIPPS INSTITUTION PIER F, P. Shepard and D. B. Sayner University of California Scripps Institution of Oceanography, La Jolla, California ABSTRACT ’ The relationship between currents inside and outside the breakers has been established by years of measurements at Scripps Institution pier. Veloc- ities in the outer surf zone are ordinarily several times those beyond the surf zone but there is little difference in the speed of currents just outside and those several hundred feet seaward of the breakers. The surf zone currents show some bias in favor of agreement in direction with those just outside but flow in the opposite direction is not uncommon. In general currents show an increased velocity with increase in breaker height. High winds have more effect on current velocity outside than inside the breakers. Introduction For five years the direction of currents have been observed at three points along the 1,000 foot pier at Scripps Institution as follows: (1) in- side the breakers, (2) just outside the breakers, and (3) at the end of the pier. For the past four years the observations have included measurements of velocity obtained by observing with a stop watch the time taken by a patch of dye in traversing the width of the pier. These measurements have been made on approximately 800 days. During these same years breaker height, wind velocity and direction, and general weather conditions have been recorded, In discussing the results of a large mass of observations of this type it should be remembered that they provide only a very incomplete picture of the general circulation of the area because they are limited to one line ex- tending less than 1,000 feet seaward. However, in conjunction with other studies on circulation patterns in the area (Shepard and Inman, 1950) they can serve some useful purpose and the comparisons of velocities inside and out- side the breakers are particularly informative. The study is somewhat strengthened by earlier records. Thus over a period of one year 210 observations of current directions inside and outside the breakers with 50 velocity measurements were obtained from Crystal pier at Mission Beach, six miles south of Scripps pier. Also a Dahl-Sverdrup current 1 Contributions from the Scripps Institution of Oceanography, New Series No. This work represents results of research carried out for the Beach Erosion Board, Corps of Engineers, Department of the Army, under contract with the University of California. meter was in somewhat intermittent operation at the end of Scripps pier between 1937 and 1910. Various other records are available but their nature has made it seem inadvisable to consider them in relation to the present study. The current measurements were made in a locality where conditions are greatly influenced by the presence of two submarine canyons (figure 1). The wave convergence just south of Scripps pier causes a predominant northward current which extends ordinarily as far as Scripps pier before turning sea- ward into a rip current. The latter is found most frequently a few hundred feet north of the pier but turns seaward at the pier on many occasions. The pier has some special influence both in retarding longshore flow and in deflect- ing currents seaward. The most common deep water wave approach in the area is from the west or northwest as is also the wind. Both of these factors tend to produce southerly currents although the wave fronts are much influenced by the canyon topography. Southerly wave approach is frequent during the summer but not important in the Scripps area due to screening by Pt. La Jolla. During most of the year the winds are light, that is, less than 10 miles per hour, but occasional winds have velocities up to 0 miles an hour. Almost all of the storms come from the northwest. The much shorter records of observations at Crystal Pier were made in an area where the submarine contours are essentially straight and parallel to the shoreline. Therefore these serve to check the results obtained at Scripps Pier where submarine canyons influence the currents. Statistical Relations of Currents along the Pier Current Velocities. The 800 measurements of velocities just inside, and outside of the breakers, and at the end of the pier allow a very substantial comparison of velocity and direction of these different environments. Figure 2 shows a cumulative curve comparing the velocities regardless of direction at the three localities. It will be noted that the median in the surf zone is six times as high as that outside the breakers, but that the velocities do not differ greatly between the zone just beyond the breakers, and at the end of the pier. Similarly the times of no measurable current are rare inside the breakers but constitute 17 per cent just outside and 11 per cent at the pier end. There were only 23 days when the current just outside the breakers or at the end of the pier was stronger than that in the surf zone. On nine of these occasions there was a strong wind which seemsto have much more influence on current velocities outside the surf zone than it does inside. On 5 other of these days the stronger current was in the opposite direction from that in the surf zone and on two other occasions there was little if any current in the surf zone. Current velocities increase roughly with breaker height as is indicated by a plot of median velocities for each foot of breaker height in the surf zone (figure 3). This is only a trend, however, and there are a consider- able number of days when relatively strong currents, mostly northerly, were 9 a | 3undl4 | 1334 NI 37Vv9S | ———— ss 5 s 0.9 po 0002 ooo! (0) Y3ld ... ° | Gn NOILVLS casters 1a34 NI auv SYNOLNOO PNG Mp NE eee ESN eee 66°66 6'66 866 S66 66 sé 06 08 OL 09 OS OF OF 0z OL S z tL Ss 20 10 S00 10°0 ° ro) fe Oo (e) 2} Oo (e) fs) B rr) dg oO S S © smaa(c) ‘ ‘ a ite) Ww ° wn = | q LEE ‘0 a= oO Cas add a ; D4 +H og | 1 | : 2 H E =H Sooo eS » eo. {| ees | 4 + sates alc Susatant asstitiantt a ¢ PEEEH H aaa Et ia HECNEEH is a 7 eo) be H gauge ee) CI I {| I [ak ae Oo (aX) $ : ig {tt ; oS e i. | eeaat x = peta oO FH (e) 10°0 G00 10 20 = 860 S Ol 0z 0€ Or oS 09 OL 08 06 sé 8 66 S66 8'66 6°66 66°66 NVHL Y3S3L1V3Y9D INS0NSd SAILVIAWNO FEET PER MINUTE FIGURE 2 observed with relatively small waves, On the other hand there are no cases where currents less than half a knot were recorded when the breakers were in excess of 9 feet. Just as most of the high surf zone currents with low breakers are to the north so most of the currents with high breakers are to the south, Outside the surf zone the current velocities are ordinarily so slow that the median velocities of all but the highest bresker heights fall in the O.1 knot grouping. Accordingly for each breaker height in these outer zones the velocity was chosen below which 75 per cent of the current velocities fell (figure 3). It will be seen that these fastest currents are roughly related to breaker height. However, as indicated previously, the high velocities are also related to high winds which accompanied many of the periods of high breakers. The latter were mostly accompanied by southerly currents outside the surf zone. Just beyond the breakers on days when breakers were 9 feet or more there were 23 south currents compared with 7 to the north. At the end of the pier with equally large breakers the notations show 22 south currents and 9 to the north. Current Directions. Table 1 shows the number of observations with north, south, and neutral* currents and the number of occasions when the current was dominantly offshore (rip currents). Table 1 Current Directions in the Different Zones Rip Currents North South (Dominantly Neutral@ Currents Currents seaward) Currents Surf Zone Number 86 213) 222 23 Per Cent 51.5 22.5 23.5 2.5 Cutside Breakers Number 334 370 96 161 Per Cent Niel 38.5 10.0 16.8 Pier end Number 30 367 ALi 102 Per Gent 36,2 39.2 14.90 10.6 The percentages show that there is a decided majority of north currents over south in the surf zone whereas the south currents are slightly in excess out~ side the breakers. The neutral currents show their largest number just out- side the breakers and their minimum in the surf zone. Rip currents are most common in the surf zone but are slightly more common at the pier end than directly outside the breakers. Since most of the rip currents in the surf 2 No net drift observed during about 10 minutes of observation. 5 zone have a northerly component the north movement is even more general than indicated by the figures. The relation between current directions in the three zones was compared for each day. The results (Table 2) show that there is a much greater agree- ment in the currents just outside the breakers with those at the pier end than Table 2 Comparison of Current Directions in Different Zones One Zone neutral or Agree in Opposed in rip current, the other Direction Direction North or South Surf Zone com- pared to Just Number 398 194 373 Outside Breakers Per Cent Nr 33 2001 38.6 Just Outside Breakers compared Number 556 126 306 with pier end Per Cent 56.3 W257) 31 there is between the surf zone currents and those directly outside. However, in view of the dominance of north currents inside the breakers and the slight majority of south currents on the outside one might have expected that more currents would disagree in direction than agree, which is not the case. There- fore, whatever produces a current ir one direction outside the surf has some tendency to produce a current in the same direction on the inside. Many of the direction disagreements are due to the fact that the current producer out- side the surf does not counteract the effect of the wave convergence on the south side of the pier. Furthermore, the cases where there is a south cur- rent all along the pier but a stronger current outside are times of strong north winds which must counteract the tendency for north flow inside the surf. Comparison with Crystal Pier The current statistics from Crystal pier observations are given in Table 3. Table 3 Crystal Pier Statistics North south Rip Neutral Currents Currents Currents Currents Surf Zone Number 92 66 ho 13 Per Cent 1.8 30.1 22 5.9 Outside Number 70 65 7 37 Breakers Per Cent 39.1 36.3 3.9 20a IN FEET o [o) @ BREAKER HEIGHT CURRENT VELOCITY IN KNOTS SURF ZONE IN FE BREAKER HEIGHT VELOCITY OF 50% OF CURRENTS LESS THAN THE VALUES GIVEN ~-—---~ NORTH x x SOUTH OUTSIDE BREAKER ZONE PIER END 10) I 2 ei OU Ge tar PEE} £) {1-@) KNOTS VELOCITY OF 75% OF CURRENTS LESS THAN THE VALUES GIVEN *------ NORTH »——« SOUTH FIGURE 3 One zone neutral or Agree in Opposed in rip current the other Direction Direction North or South Surf Zone Number 97 30 36 compared with Outside Per Cent 59.5 18.4 emi Breakers The velocity measurements are based on 49 measurements inside the breakers and 22 measurements outside. These give a median velocity of 0.55 knots in- side and 0.23 knots outside, that is, a ratio of 1 to 2... The faster average currents outside the breakers than at Scripps pier are probably re- lated to the larger agreement in direction in currents inside and outside the breakers at Crystal pier. It is also possible that the small group of ob- servations has not given an average picture. The agreement of currents in direction inside and outside is far larger than between the same two zones at Scripps pier. The larger number of north and south currents may not have much signifi- cance. Some weekly observations along the beach near the pier over the course of a year showed slightly more south than north currents. Current Meter Studies at Scripps Pier It is difficult to compare the Dahl-Sverdrup current recordings at the end of Scripps pier made during much of the period between 1937 and 1940 with the daily observations of recent years. The recordings were made by a current meter suspended 8 feet below the surface and operated electrically. The re- cords were averaged by E. G. La Fond for each hour, each day, and each month but the results were never published and some of the data are missing. The records indicate that the currents are predominantly slow as was the case in the recent observations, Daily averages show that the net current was north on 182 days and south on 212 days which is approximately the same as for our observations. Velocities of north and south currents are similar. Examina- tion of records indicates that the current direction frequently changed during the course of a twenty-four hour period and often when the current was pre- dominantly in one direction there were two periods in the course of the twenty-four hours when it was reversed. These reversals, however, did not take place with any clear relation to the tidal cycle. On many days the current was continuously in the same direction. It is difficult to be sure whether or not the tide is an important factor in these currents. Acknowledgments The writers desire to express appreciation for the help given by R. L. Wisner, Ruth Young, and J. R. Moriarty in making many of the observations. Suggestions in connection with the work were kindly supplied to us by Mr. D. L. Inman and Dr. R. S. Arthur. Reference Shepard, F. P., and D. LE. Inman, 1950. "Nearshore Water Circulation Re- lated to Bottom Topography and Wave Kefraction," Trans. Amer. Geoph. Union, Vol. 31, No. 2, pp 196-212, CHARTS AND TABLES FOR DETERMINING SURFACE STONE SIZES FOR RUBBLE MOUND STRUCTURES IN WAVE ACTION by W. H. Vesper and Kenneth Kaplan, Engineering Division Beach Erosion Board INTRODUS TION Data pertinent to the design and construction of rubble mound structures for resisting wave action have been compiled and are presented here in limited tabular and graphical form. The methods of calculation for stone sizes and related slopes are based upon translations of the works of Ramon Iribarren Cavanilles and Casto Nogales y Olano. These translations appeared in the Beach Erosion Board Bulletin, Volume 3, No. 1, January 199 and Volume 5, No. 1, January 1951. The equation used to calculate the stone sizes is the dimensionally homogeneous form of Iribarren's formula developed by Robert Y. Hudson, M. ASGE and presented in Transaction of the American Society of Civil Engineers, Volume 116, 1951. Terms and Symbols oe «ss Breakwater slope angle with the horizontal M « Effective coefficient of friction, rock on rock (= 1.09) da = Depth of water at the breakwater's position se u Wave height at the breakwater's position in the absence of the breakwater Hypothetical wave height with orbital velocity the same as exists at depth d with a surface wave height of H, = tt H, = Deep water wave height associated with H H' g = Deep water wave height associated with H, if refraction effects are ignored. Wave height over points on the breakwater slope showing the steepening effect of the breakwater a +33) fk K = An empirical dimensional coefficient in Iribarren's original equation (1) K! = An empirical dimensionless coefficient in Hudson's modified equation (2) 10 aw 5 i Refraction coefficient of the breakwater's depth d inal tl} Wave length at the breakwater's position Lo = Deep water wave length Sp = Specific gravity of the fluid in which the breakwater rests Sy = Specific gravity of the breakwater rock Yy = Unit weight of fresh water W = Stone weight General Equations In the article, "A Formula for the Calculation of Rock Fill Dikes," (1) Iribarren presented formulae for the design of rubble mound structures. These formulae permitted calculation of sea-side slopes and weight of individual stones above the water surface. His result for the calculation of the weight of cap rock, in wide use for many years, is WKS W = = (1) (cos & - sin & 3 (S, - 1)? where Sp = specific gravity of the rock e = the angle the sea-slopes makes with the horizontal (A slope is usually referred to as l/cot. ) H = wave height (in feet) W = weight of stone (in tons) _K = an empirically determined coefficient for all unevaluated variables 4.68 x 1074 for natural rubble 5.93 x 1074 for artificial blocks This equation however, is not dimensionally homogeneous and has been modified by Hudson (3 » using the same assumptions and force diagram as Iribarren ale to obtain 5) 3 3} K! er S S,A H wie ie r (2) (A cose - sine )? (oa a)" in which the additional symbols are: t i unit weight of fresh water Sp = specific gravity of the fluid in which the breakwater rests WZ) K! effective coefficient of friction rock on rock, & 1.09 a variable dimensionless empirically determined coefficient, values of which as determined by Hudson are plotted in Plate 4. the equivalent values for equation (1) are K' =0.015 for natural rubble K' = 0.019 for artificial blocks The Equations for the Weight of Above Surface Stones Equation (2) may be reduced to ta o 3 r W = 88.3 K! Yr H (3) (1.09 cose - sinee )? (Sp - 1.03) if the breakwater is founded in sea water; or may be reduced to c aia 1.7 el SB. Be W = 80.7 K! Yr H (1) (1.09 cose - sinee)? (Sii=a)iz if it is founded in fresh water. The wave height H to be used is that height which would exist in the absence of the breakwater, This wave height at the breakwater's position may be related to a decp water wave height H, by eo Tel (yA) os Tc (5) where H, = the deep water wave height a 7] x $ i the refraction coefficient at the breekwaters depth (determined from refraction diagrams) (H/H'..) = the shoaling coefficient, values of which are tabulated in fo) ROMerencemo (HE is the wave height at depth d if ume eee eee by refraction) . a2 The Equations for Weights of Subsur: fata of sub-surface stone gales.\¢) In this method, a % sd, whose maximum een velocity is the depth d. This value is The only method presently available weights is that suggested by Iriba hypothetical wave height H' is the same as that which exists a is 2 wu Ble (6) Oe esha ea L where awe the height of a wave steepened by the breakwater, is d etalaeas by SUA E Tg equation (5) to points over the breakwater slope. This hypothetical } 19 wave height is then substituted in equations (3) or ()) with K' - YG ke or 0,019 (as determined from Iribarren). Charts and Tables The following charts and tables have been included to facilitate the solution of the basic equation ; Comes (Hier He WW ON oy (7) (1.09 cosee - sinee )3 (S.= Se)3 where 1.03 for seawater Q fh Cc Cc 5 LSS) 5 t Q tw Lean} iy} =z 1.00 for fresh water. ta h —~ ro f= fut} 3} Q wm Hy tf Table 1 - lists values of _angleee , the slope ratio, and (1.09 cose - sino \3 for slopes ranging from 1 on 1.1 to aL igi ALO) Plates 1 to 5 - are curves showing the variation of W/K' from equation (7) for seawater, with wave height H (or H'). Values of the functions have been computed for slopes of 1 on 13 to 1 on 10 with stone density being used as @ parameter. hows the variation of K' with d/L for slopes ranging Plate 6 = sh nea dl copay de Te) AL xenay 3} f+ ww Applications Since the equations for above surface and sub-surface stone weights are not entirely compatible, the determination of sub-surface weights as outlined above should be restricted to depths below a wave height from the surface; slopes for above surface stones being carried down to that level. The crest height of a breakwater should be at least one and one-half wave heights above design water level. Sample Problem A breakwater is to be founded in sea water, in a depth at one place, of 70 feet below MHW. Inspection of the quarry indicates that the maximum average stone weight available will be 10 tons with a specific gravity of 2,05. To utilize the quarry to the fullest extent, three stone classes are to be used with average weights of 10 tons for class A stone, 5 tons for class B stone, and 500 pounds (quarry run) for class C stone. The wave attack for design at the structure's position was determined to have a height of 15 feet and a length of 450 feet, and to approach from such a direction that the refraction coefficient at that position is K,s l. From reference 6 when d/L = 70/450 = 0.1553, d/Lp = 0.1167 and H/H',) = 0.922 wimeneieres ll Oo TO & 600 feet and Eee SE: 56 ikea 3 0S ( aL 5 555) = 16227 feet. Above surface stone weights and slopes - From Plates 3a and 6 stable slopes for various stone weights may be fixed in the following manner. -W Slope W/K' (Fig. 3a) K' ("ig. 6) Pounds Tons Lon 3 B05 NO? 0.038 19,000 9.5 Jon 2) 1/25) x.1106 0.022 27,500 13.75 The last column shows stone weights stable on slopes of 1 on 3 and 1 on 2 respectively under this particular wave attack. For this problem since the class A stone averages 10 tons, the slope of 1 on 3 will be chosen for the cap rock. Sub-surface stone weights and slopes - The calculation sheet following summarizes the steps necessary for the determination of H, and H' of equation (6). These values are olotted on Figure 1. The cap rock and attendent slopes are carried down to a depth of one wave height (15 feet) and the class B 14 rock to a depth of 4O feet. At the depth of 15 feet, H' = 10,0 fret. for Kt = 20.8 feet and W = 10,000 pounds W/K! = 6,67 x 10°, Entering Figure 3a with these values the slope is found to be approximately 1.75. Similarly at the depth of 0 fect, H! = 2.33 feet and with W = 500 pounds and K! = 0,015, W/K!. 2 3.33 x 104, Fron plete 3a the slope is about 1 on 1.25. The following table summarizes the sea side slepes necessary for a stable section. Depth Stone Weight Stable Slope (feet) (tons) O 10 i ia 3) 15 5 i on 1 3/7) )0 = 1 on a U/l The resultant stable profile is plotted on Figure 2. Acknowledgment The writers wish to express their appreciation to Richard H, Allen for Calculaticus performed for this paper. 15 06° of BOLT "8TH" 00 (1 u0oy4 dg) B 0) qo 128 22-112 Gwar GS-9 HOTT °o OL ai rm us i i WHS NOTLVINOTYO OG eoual “One ashi io) (o) \o i (e) ri T6°0 007082 (Gite (O22 1 ie 98°90L YA OIES CO° ude 00°ST iB t/pee surs OF T/o “2 j4UTS S aL a i s 2 H °1.8/8 T/p42 yuts On fp p (G uotqendg) y x OH (°\H/H)= SH 16 Wave height Hor H. ie} 4 8 12 16 20 Ol ater ae Ge mea | oa , oral 20 30) H'= 1 HE L_sinh2 201d © L Wave height of hypothetical sub surface wave. Depth below still water level (feet) 50 Wave height of surface wave increased by the wave steepening effect of the structure. H=(4)xH xk Si ignecomn | H, AND H' VS. WATER DEPTH (See calculation sheet, page |6) Fig.l USS CA Ka 0 SEE SEA- SIDE PROFILE OF BREAKWATER Fig.2 17 (6) Bibliography Ramon Iribarren Cavanilles, "A Formula for the Calculation of Rock Fill Dikes" (Translation) Bulletin of B.B.B., Vol. 3, No. 1, January 1) 19h9 9 pp ue ~15.6 Ramon Iribarren Cavanilles and Gasto Nogales y Olano, "Generalization c of Rock Fill Dikes and Verification o the B.H.4., Vol. 5, No. 1, January 19 a ’ the Formula for the Calculation its Goefficients" Bulletin of 1, pp 4-2. y FS oO ST Hudson, Robert Y., Discussion of Paper No. 2372, "The Problem of Wave Action on Earth Slopes" by M. A. Mason, Transactions of the Am. SoC. of Civil Engineers, Vol. 116, 1951, pp LhON=1h05. Hudson, Robert Y., “Wave Forces on Breakwate: edings, American Ci I Tab sag Society of Civil Hngineers, Vol. 78, Separate No. 115, January 1952. U. S. Hydrographic Office, “Breakers and Surf, Principles in Forecasting", H. O. Pub. No. 234. November i9lh. The Bulletin of the Beach Erosion Board, “Oscillatory Waves", Bulletin of the B.E.B., Special Issue No. 1, July 19h6. Slope angle slope ratio Siope and friction function {ein degrees) (cot. o¢ } (1.09 cose = sine)? 5° 1 2° 161 Let 39° 118" sire 38° ho! 1525 Sie sou! 133) 25 ye Leb S13 sa LoS Bn OO! 1.6 29° si to 0.0912 26° 3h! 2.00 O.L7 23° 56) 2.25 0,205 PAN} 2.5 0.258 19° 59! .75 0.315 18- 26! 3 C.370 17° 06! 225 0.418 m 49 ORM ey Vie EE U1) COND en © Sa ~ 0 y) dans 65) ie ee): 52 0.503 ik? 02 0 0.541 5 025 0.576 We 30 65) 0,608 ae , fe) {2 0.636 aint cea} € 0.66 10" 16! 5 Oma ee 26! 3G Oey E 5 5 (8) m 0.86) . 4 fod Q Nat Lo (SY N92) We) 162) SON SGN ON WAG dS a) PEE OSS) MUONS) NG} [hel Th . © 081 0 0.878 rats} 5 0.906 ay 20" i 0,921 tO a) 0.939 shale 10.0 0.955 i 3291d (op'z=4S @ O¢'Z2 4S) 2d07S USAVANVSUS 4O SBNIVA SMOIMYA YOd LHOIBH aAvm Sa —#NBidiss909 3218 3NO1S rom tr eo) , 168 / IHSISM SNOLS z T6349 LNZISH BAVA 1334 NI LHSIBH 3AVA BL é : £ 41N319!3330) 3ZiS 3NO1S SGNNOd NI SANOLS dVD 430 LHOISM nm A 20 2 a1lvid 41N319143309 3ZIS ANOLS waLvmyvay"d JO SAMIVA SNOINVA YOd LHOISH 3AVM SA — = THSIaM «OSNOLS) SNOLS s 168 ft 9 Ig @ OG'z= 4S) 3d01S 1639 t z 16849 § (o9°2= 4 v £ @ I 1334 NI LHOIBH JAVM L N3I91 S 43309 32'S _ 3NOLS SONNOd NI SANOIS dvd JO LHOISM nono wo LHSIZH SAVM 12334 NI 2 € 31V1d (oz2=45 8 S9'2=4S) 3dO1S USLVMNVaYS JO SSMVA SNOIMVA HOs LHOISH 2AVM SA — ANS ao (GOR @ PS b & Zz WG RR 8) ¢ & a tO Ao GY € Zz (GR @ & Gv £ Zz WG @-O Gt £ Zz i = mn x= my £2) as =) z m | z ; ‘ele 1 i ah: | eal | @g i Ss as Sa ia a | es |e see | 6 a) b | Ses | se | es |S 3 E Fae eal L = - . ; 25 Se ee ee Siersiesiaee | [ z | § Teale] 5 = T z 5 F IE [| L al: | EEE . if 5 l SElscalesicsl i TI [ =I l caSSra iieeiesees ijieiereet , 6 | ae EAB 4 IES ; ! seal 001 Gok gy aay £ 5 Ol 68 £9 4N319133309 3ZiS ANOLS Oo SGNNOd N! SSNOLS dV¥D 4O LHOISM M 22 WEIGHT OF CAP STONES IN POUNDS STONE SIZE COEFFICIENT Ah Ki” aie eee BREE SAVY SIBEIE) Hee nc 7 AM WW A AY \ A i \\ cm \ SES siomtaar Vay Ne (asta fem DING Wea Ge es IE cI WAVE HEIGHT IN FEET | ae | aw bolaaieas bial cecal Oraneon - 4334 NI LHOIZSH 3AVM 23 peel = ; 45 891 2 3 6 7 2 3 VS WAVE HEIGHT FOR VARIOUS VALUES OF BREAKWATER SLOPE (Sr, 22.75 & S,-=2.80) STONE WEIGHT STONE SIZE COEFFICIENT PLATE 4 (oo'e=7S 8 O6 a= 4s) G 31LVid 3dO1S YW3LVMNVSES JO SSNIVA SNOIWWA YOS LHSISH SAVM SA RAZ F 168 4 9 41N3191333509 3ZIS 3NO1LS IHOIBM SANOLS 41N319133309 3Z!IS_ 3NOLS SONNOd NI SANOLS dVD JO LHOISM A 1334 NI LHOIZH 3AVM 24 VALUES OF K! 0.05 o AVAILABLE DATA (W:2.7 x 104LB., Sr 228, Us 1.09, Wr = 45%) 0.03 0.02 0.01 (1 ON 1.25) (1 ON 1) fo) 0. 0.2 03 04 0.5 VALUES OF s VALUES OF COEFFICIENT K'! PLATE 6 25 JAPANESE RES#ARCH IN PHYSICAL OCEANOGRAPHY ,19)8-1950 Recent infomation prepared by Dr. Koji Hidaka, Geophysical Institute, Tokyo University, Tokyo, Japan, regarding oceanographic research in Japan during the period 198 to 1950, has come to the attention of the Beach Erosion Board. Dr. Hidaka indicates that research institutions in Japan which normally accomplish oceanographic work are rapidly recovering from their period of forced inactivity in this field brought about by World War II. Agencies of the Japanese Government which have been accomplishing a program of oceano- graphic observations under control of the Occupational Forces are specified as follows: 1. The Hydrographic Office, Maritime Safety Agency, Tokyo. 20 Seven Fisheries Research Laboratories located throughout Japan, including the one at Tokyo. 3. The Central Meteorological Observatory at Tokyo, and subordinate Marine Observatories at Hakodate, Kob?, Maizuru and Nagasaki, with other lesser coastal meteorological stations. Organizations coordinating or publishing the results of the research are: (1) the Three Agency Marine Research Coordination Council, made up of re- presentatives from the agencies of the Japanese Government listed above; 2) the National Committee on Geophysics, Section of Physical Oceanography which Dr. Hidaka heads as chairman; and (3) the Oceanographical Society of vapane Dr. Hidaka's description of Japanese research accomplished concerning waves, tides and related subject is presented in the following paragraphs. Kee KEE Waves in General. The studies of waves in general are active throughout the world now and many eminent accomplishments have been done in the United States, Great Britain, Germany and so forth n this country, investigations in the same field are also active. Tonga made an attempt to obtain the approximate solutions of the wave equation and their applications. He also Teo the reflection coefficients for tide-waves, tsunami and swell. (30 In 1950 Kurihara and Teubaki (31) discussed the generation of roll waves in shallow, flat-bottomed channel, use being made of the theory of turbulence. Wind Waves and Swell. In 1950 Yoshida(32) published a theory of the period increase of waves in storm area. He also explains the surf beats as named by Munk in the same way as the overtides and compound tides are derived. Furthermore he suggests that their frequent occurrence may be ascribed to the general structure of the ocean-wave-spectrum. Ichie(33) discusses 26 the waves to be emitted when a pressure oscillation suddenly begins at a limited area of the sea, and intends to explain the generation of swell. Masamori Miyazaki(3l) published a statistical study of the breakers, use being made of the observations along the coasts near Tokyo during the period 194-1915. The relation between the typhoons and swell and microseisms was investigated by Kabazawa(35) and Kimura.(36) Recently Sato(36) published the investigation of the wind waves caused by the typhoon "Kitty" of 19h9. He(37) also examined the surfs by the stereophotogrammetry. In 1950 Yoshida(3& investigated how Comoe currents are deformed as they approach the coast. Miyazaki 39) showed that the amplitude of the surface waves in a fluid moving in a fixed direction depends upon its direction of propagation. Yamada\40) considers a method of obtaining electricity from ocean Waves. Tsunami. Many investigations have been carried out recently in this branch, presumably because this country abounds so much in this phenomenon. Yoshida's theory (30) on waves in general is, of course, applicable to tsunami. But there are many researches related to pure tsunami, especially after the Aleutian Tsumami attacked the Hawaiian Islands in 1946. Hidaka and Hikozaka\41) made a mathematical research on Hawaiian tsunami, obtained the waveheight on the coasts of Kauai Island, assuming this island to be circular in form, snd compared the result with the observations. (It should be remembered that nearly the same computation was made by Homma, 1) and by Omer in America, though the laws of depth around the island are different. Recently Okano(42) published a possible explanation of the un- equal heights of Aleutian Tsunami around the Hawaiian Islands. Hikozaka 3) recently treated the refraction o tidal waves by a shoal with parallel straight bottom contours. Yoshida 4) discussed the partial reflection of long waves travelling in a canal of varying section and its application to the occuirence of seiches in the sea. There are so many theoretical in- vestigations on tsunami. Matsuzawa) gave a Sate for the generation of tsunami due to the bottom disturbances. Ichie 4 treats the dissipation of the energy of tsunami by reflection and frictional effect during its course over the shelves, and the esppas (h7 caused by a distrubance travel- ling along the ocean floor. Takagi (45 discusses the theory of tsunami invading the continental shelf and intends to investigate whether the periods recorded in tsunami attack are those peculiar to the original pee ie or those caused on invading the bays as the stationary undulations. He 9) also obtained the records of sea shock on 10 August 1949 by installing a seismograph on board an anchored ship. Recently Homma O) treated the distribution of heights in tsunami obliquely attacking a straight coast. Several] authors made model experiments on the propagation of tsunami. In this respect we can mention the work of Ogiwara( 1) on the effect a viscosity on model experiments of tsunami and that of Ogiwara and Okita 52) for the case of aa? invading Shizukawa Harbor. Another model experi- ment was made by Ichie for the invasion of tsunami into Osaka Bay. Recently Ichie (54) discussed the sudden changes of the density and temperature of the coastal waters induced by the influence of typhoon and depressions offshore. Tides, Tidal Currents and the Mean Sea Level. Many researches on the tides and tidal currents have been done during the three years. In 19)8, Hidaka(55) made an attempt to analyse the tidal records without using the harmonic constants with a special intention to treat short series observations of tidal currents. He called it "the qualitative analysis" and result was not necessarily successful, though there may be cea anticipations to be applied to some geophysical phenomena. In 1949 Uda reported that, in the waters of complicated bottom configuration rich in islands near Nagasaki, the tidal currents near the bottom frequently flow in a direction opposite to those in the surface layers and discussed the stratified,currents with the internal waves which dominatedin summer of 198. Miyake(5? considers the use of statistical machine for carrying out the harmonic analysis of the tides. Yamada( 58) suggested a graphic method of constructing the ellipses of tidal currents. Recently Yasui and Ishiguro(29) made avery intensive study of the tidal currents in the Hirado Seto (Hirado Strait) near Nagasaki on the intention partly to protect the ships from wreckages and partly to treat this pheno- menon from the oceanographic interests. They made, in addition, a series of model experiments to make the description complete. Observations of tidal currents were mae ca the Irako Channel by Ono , (60) off Mera (Yamagata Pref.) by Umeda. \°L In 198, Hikozaka\62) applied Grace's method of numerical inves aes on the semi-diurnal lunar tidal motion of Shimabara-Kaiwan, Kyushu. He\©3) also tried a mathematical analysis on the diffraction of tide-waves by an island of an arbitrary shape. Recently Techie (OL) published a theoretical result on the abnormal high sea level (meteorological tides) caused by storms travelling off the coast. A theory of an abnormal piling-up of water against the coast due to travel- ling pressure disturbances was established by Yamada. (65) He took the effect of eddy viscosity into account. No outstanding investigation has Bae made in the field of dynamical theory of the tides. Recently Hidaka(© considers a possible method to treat the dynamical tides in a quadrangular ocean on a rotating globe by the use of Galerkin's method of approach, The problem on the variation of the monthly mean sea level were recently discussed by Shimizu 7) and Yamaguti,(68) the former by means of a statistical analysis and the latter on the reliability of the values. ; Seiches and Stationary Oscillations in the Sea. In 1948, Hidaka and Yasuil69) computed the seiches of Lake Inawashiro use being #385 of Proudman's integral method and Hidaka's node method. Recently Miyazaki 10 computed the undulations of the Miyazu Bay by using Chrystal's method. Wiehe studies of this phenomenon may be also mentioned. In 199 Saito 71) usea the total flow method to treat the seiches in lake. Ichie 12 computed the manner in which the energy of seiches escapes out of the bay, especially of small depths and the relation between the occurrence feasibility of seiches and the variation of winds. Nakano\?3) explained in 1949 the 1=3 minute <8 surf beats as the waves generated and propagated from the storm centers, and intensive study being made of the prevailing meteorological conditions in this connection. Recently Unoki (74) published a very important paper on the fluctuations of sea level caused by the variation of atmospheric pressure. He derived that the bottom friction of sea water can be considered proportional to the velocity of the water near the bottom and applied this conclusion for ex- plaining the lag between the travelling pressure disturbances and resulting level fluctuations, the agreement between theory and observations being satisfactory. Internal Waves. As to the study of internal waves, we may mention Ichie's recent work. He examined theoretically the effect of bottom configuration upon the internal waves, assumption being made that the undulations of bottom are small compared to the depth of the water. Under Water Illuminations. The cay oceanographer engaged in marine optics in this country is Takenouti. He 76) made a series of measurements of underwater illuminations by the use of photronic cells and color filters, and explained the results theoretically. He was thus able to determine the diffusion ratio of underwater illuninations. Submarine Deposits. Tayama(77) pave a chart of the bottom deposits in the adjacent seas of Japan. Niino also made a great contribution to the submarine geology in the adjacent waters of Japan. Instruments. S. Watanabe is a very able thermometer maker in this country and has supplied thousands of reversing thermometers for home use up to the present. Last year the writer recommended his products to Dr. Sverdrup, Norway, to Dr. T. G. Thompson, Seattle, and to Dr. Revelle, of the Scripps Institution of Oceanography, La Jolla, California. Dr. Dale Leipper, of the Agricultural and Mechanical College of Texas, uses Watanabe's thermometers for the hydrographic survey of the Gulf of Mexico. Dr. Thompson is now re= questing an additional supply for his laboratories. In 1949, another Watanabe(79) constructed resistance thermometers for hydrographic use and discussed on the Joule effect which brings difficulty for using this instrument at sea. Kohei Ono, of the Hydrographic Office, Maritime Safety Agency, devised an electric current recorder which can be used suspended from an anchored buoy. This instrument will be the sole current recorder now in practical use in this country. Shizuo Ishiguro (80) is a very able hydrographic mechanician and de- vised many instruments. In 1949 he constructed an electrical recorder for sea wave pressure. Recently he constructed two types of wave recorders for Wind waves and swell and an apparatus for the stroboscopic analysis for preparing the wave spectrum. He also constructed an electric remote wave recorder in which the pressure element is used submerged on the bottom of the sea near the coast, Hydrographic Office also devised a wave recorder of pressure type under Y. Tsukamoto's direction. Yoshida and Kajiura used this instrument for the observations of surfs along the Japan Sea Coast. In 199, Hishida(81) considered the shape of sounding wire in the water from the observations by the non-protected reversing thermometers. Publications. At present the following publications of oceanographical interests are issued from the institutions and societies in Japan. The Tokyo Fisheries Research Laboratories, Oceanographical Division (1) (2) (3) Kaiyo-zu (Oceanographical Charts, chiefly for fisheries workers, in Japanese) reports the distribution of temperature and salinity three times a month. Kaiyo Tyosa Yoho (The Oceanographic Observations): List of oceano- graphic data obtained by all fisheries agencies. Suisan Kenkyujo Gyoseki Shu (Contributions from the Fisheries Research Laboratories) 1950-. The Hydrographic Office, the Maritime Safety Agency, Tokyo. (1) (2) Suiro Yoho (Hydrographic Bulletin, in Japanese): bi-monthly, con- tains mainly quick information on the observational data in hydro- graphy and miscellaneous. Kaisho Iho (The Oceanographic Bulletin): irregular, contains the results of observations and miscellaneous, 197-1950, suspended from May 1950. The Central Meteorological Observatory, Tokyo (CMO), Division of Oceanography. (1) (2) (3) (h) Kaikyo Gaiho (Preliminary X.port on the States of the Seas adjacent to Japan, in Japanese). Three times a month, 196- (No. 1)2 in the middle decade of September 1950). Kaiyo Hokoku (Oceanographical Report of CMO, in Japanese) 1 (1) 199, L, (2). 1950, The Oceanographical Magazine (quarterly, in English and other languages) 1 (199), 2 (1950-): This contains papers on oceano- graphy and marine meteorology. Nippon Kinkai Kaikyo Gaiyo (in Japanese) reports the general hydrographic conditions in the seas adjacent to Japan as derived from the observations during past one year, 19)9-. 30 The Kobe Marine Observatory (1) Papers and Reports in Oceanography (In English), Nos. 1-) (199), No. 5 (1950). (2) Kaisho Geppo (Monthly Report on the Hydrography in the Adjacent Seas of Japan, in Japanese) reports the data observed in the seas, and along the coasts and other various oceanographical phenomena, 1950-. (3) Memoirs of the Kobe Marine Observatory (In English) being a con- tinuation of the Memoirs of the Imperial Marine Observatory. (4) Choseki Hokoku (Tidal Observations), 1950-. (5) Kaiyo Ziho (Journal of Oceanography, In Jepanese), irregular presently. The Maizuru Marine Observatory. (1) Oceanographical Reports (in English). (2) Kaikyo Gaiho (General Hydrographic Bulletins, in Janapese). (3) Kaiyo Kisho Kansoku Hokoku (Reports on Marine Meteorological Ob- servations, in Japanese). The Nagasaki Marine Observatory. (1) Kaisho to Kosho (Oceanography and Meteorology, in Japanese), 1 (1947)- (1950). (2) Kaikyo Ryakuho (Journal of Oceanography, in Japanese) 197-199: continued by "Kaiyo Kansoku Hokoku" (Reports of Oceanographical Observations, in Japanese). - : (3) Nishi Nippon Kaikyo Zyumpo (Western Japan Hydrographical Bulletin, in Japanese) Three times a month. (4) Nagasaki Kaiyo Kisyo Dai Hokoku (Report of the Nagasaki Marine Observatory, in Japanese and in English), 1 (198)- 3 (1950). The Hakodate Marine Observatory. (1) Kaiyo Ziho (Journal of Oceanography, in Japanese) irregular presently, The Oceanographical Society of Japan, Tokyo. (1) Journal (quarterly, scientific papers in Japanese, English and other languages). y 31 (2) Kaiyo no Kagaku (Science of the Sea), monthly, popular magazine, now suspended for economical reason. Kaiyo Kisho Gakkai (The Marine Meteorological Society), Kobe. (1) Umi to Soro (Sea and Sky, in Japanese) aaa contains papers on oceanography, meteorology and géophysic en Ue aa Tp te St ie Abbreviaticns: REFERENCES TAGU : Transactions of the American Geophysical Union GM : Geophysical Magazine OM : Oceanographical Magazine KS : Kisho Shushi (Journal of the Meteorological Society of Japan) US 2 Umi to Sora (Sea and Sky) MKMG : Memoirs of the Kobe Marine Observatory HB : Hydrographic Bulletin (Suiroe Yoho) OB : Oceanographic Bulletin (Kaisho Iho) BSSF : Bulletin of the Japanese Society of Scientific Fisheries. (Nippon Suisan Gakkaishi) JOS s Journal of the Oceanographical Society of Japan (Nippon Kaiyo Galena) GN : Geophysical Notes, Geophysical Institute for Fluid Engineering (Ryatal Kogaka Kenkyusho Hokoku) SRTH : Scientific Reports of the Tohoku University LT : Low Temperature Science (Teion Kagaku) FE 3 Reports of the Research Institute for Fluid Engineering (Ryutai Kogaku Kenkyusho Hokoku) ZIS : Zisin (Journal of the Seismological Society of Japan) CK 3 Chuo Kishodai Kenkyu Jiho (Journal of Meteorological Research) CL $ Chuo Kishodai Iho (Bulletin of CMO) JMR 3; Journal of Marine Research BGSI : Bulletin of the Geographical Survey Institute eferences (29) Yoshida, K.: GN 3 (13) 1-a- (1950) (30) Yoshida, K.: GN 3 (14) 1-5 (1950). (31) Kurihara, M. and T. Tsubaki: FE 6 (1) 1-27 (1950) @e; Yoshida, .K.: GN3(2) 1-8 (1950) (33) Ichie, T.: JOS 5 (1) 1-12 (199) (3h) Miyazaki, Masamori: US 28 (3) 12-15 (1950) (35) Kabazawa, M.: CK 1 (7) 198-206 (199) (36) Kimura, I.: CK 1 (11) 35-358 (1949) Sato, K.: HB 16 280-293 (1950). (37) Sato, Ke: HB 15 215- (199) (38) Yoshida, K.: GN 3 (15) 1-5 (1950). (39) Miyazaki, Masamori: OM 1 (2) 133-13h (199) (40) Yamada, H.: FE 5 (2) 11-15 (199) (41) Hidaka, K., and S. Hikozaka: JOB 5 (1) 28-31 (1949) Homma, S: GM 21 (3) 199-207 (1950) (42) Okano, T. : CK 2 (2) 23-53 (1950) (4.3) Hikozaka, S.: GN 3 (8) 1-8 (1950) (4) Yoshida, K.: GN 1 (31) 1-1h (198) (45) Matsuzawa, T.: ZIS 1 (1) 18-23 (1948) (46) Ichie, T.: US 27 1-15 (1949) (47) Ichie, T.: MKMO 8 12-18 (1950) (48) Takagi, S.: GM 16 (2-4) 71-76 (1948) 33 (49) Takagi, S: US 27 (5) 13-1h (1950) (SO) Homma, S.: KS 28 (lk) 130-136 (1950) (51) Ogiwara, S.: SRTH Ser. 51 (199) KS 27 (8) 253-256 (19h9) (52) Ogiwara, S., and T. Okita: SRTH Ser. 5 2 (1) 58-65 (1950) (53) Ichie, T,: US 26 (5-6) h-6 (1949). (54) Ichie, T.: MKMO 8 19-25 (1950) (55) Hidaka, K.: GN 1 (37) 1-11 (1948) (56) Uda, M.: Kaiyo to Kisho (Oceanography and Meteorology) 3 (1) 1-(19)9) (57) Miyake, T.: CK 1 (13) 439-l5 (1950) (58) Yamada, T.: OB 9-20 (199) (59) Yasui, Z., md S. Ishiguro: CI 31 (4) 1-111 (1950) (60) Ono, K.: HD 13 79-99 (199) (61) Umeda, T.: HD 13 100-102 (1949) (62) Hikozaka, S.: GN 1 (39) 1-1) (1948) (63) Hikozaka, S.: JOS 5 (1) 32-37 (1949) (6h) Ichie, T.: CK 1 (13) 426-433) (1949). (65) Yamada, H.: FE 6 (1) 28-38 (1950) (66) Hidaka, K.: GN 3 (9) 1-6 (1950) (67) Shimizu, T.: BGSI 2 (1) 1-1) (1950) (68) Yamaguti, S.: BGSI 2 (1) 15-26 (1950) (69) Hidaka, K., and M. Yasui: GM 15 (2-4) 5-9 (1948) (70) Miyazaki, Masamori: US 28 (2) 10-12 (1950) (71) Saito, Yasukazu: KS 27 (1) 20-25 (19h9) (72) Ichie, T.: JOS 6 (1) 8-1) (1950) Ichie, T.: US 26 (5-6) 17-18 (199) 34 (73) (7h) (75) (76) (77) (78) (79) (80) (81) Nakano, M.: OM 1 (1) 13-32 (199) Unoki, S.: OM 2 (1) 1-15 (1950) Echie, T.: JOS 6 (1) 1-7 (1950) Tekenouti, Y.: OM 1 (1) 43-48 (1949) Tayama, R.: HB 15 231-235 (199) Niino, H.: Journal of Sedimentary Petrology 18 (2) 79-86 (198); Japanese Journal Of Geology and Gecgraphy 21 (1-)) 193-225 (199); Report of the Fisheries Research Committee (Suisan Kenkyukai Hokoku) 1 64-77 (1949) Watanabe, K.: US 26 6-6) 8- (199) Ishiguro, S.: OM 1 (3) 135-11 (19,9) Hishida, K.: JOS 5 38-0 (1949) 35 PROGRESS REPORTS ON RESEARCH SPONSORED BY THE BEACH EROSION BOARD Abstracts from progress reports on several research contracts in force between universities or other institutions and the Beach Erosion Board, together with brief statements as to the status of research projects being prosecuted in the laboratory of the Beach Erosion Board, are presented as follows: Mo Scripps Institution of Oceanogra hy, Quarterly Progress Report No.13, July-September 1952. SEASONAL VARIATION IN BEACH AND NEARSHORE SEDIMENTS The study of the seasonal variation in texture and composition of beach and nearshore sediments in the La Jolla area is nearing completion. All of the laboratory work and drafting have bem completed. Among items of interest from this study are the extreme variations in the content of mineral components such as mica (see previous Prog. Report) and heavy minerals, and the effect these variations have on particle-size distribution when analyzed by sieve and by hydraulic methods. Comparison of Sieve and Settling Tube Results of the particle-size distributions obtained by sieve and Emery settling tube were compared for 137 samples having various amounts of heavy minerals, micaceous material, and shell fragments. In general the results could be divided into several groups, depending upon the size of the material and the percentage of heavy minerals, mica, and shell fragments. It was found that the concentration of these constituents must be 15 per cent or more of the total sample before having an appreciable effect on comparisons of sieve and settling tube data. However, when present in these concentrations, all of the constituents caused noticeable changes in the median diameter and in the measures of standard deviation and skewness. In general the measure of the standard deviation was numerically greater for cases where the sediment was analyzed by sieving than where analyzed by the Emery settling tube, particularly for samples with high concentration of heavy minerals and micaceous material. Since the standard deviation is a measure of spread or sorting, this indicates that the sediment distribution is more homogeneous when considered in terms of hydraulic size, as in the case of the settling tube rather than geometric size, as in sieving. Distribution of Heavy Minerals The total amount of heavy minerals varied from 1.7 to 26.7 per cent in the sediments from Scripps beach and intercanyon shelf, while the coarse sands from the Point La Jolla pocket beaches commonly contained less than 1 per cant and one sample from the beach north of Scripps had more than 70 per cent heavy minerals. 36 There is some correlation between the heavy mineral content and the median grain-size of the total sample. Sediments with sieve medians near 1/8 mm usually have the greatest amounts of heavy minerals, while the abundance decreases for coarser and finer sediments. However, location and season appear to be as important as size in determining the concentration of heavies. As shown in Figure 1, the greatest percentages occur on the beach foreshore, and the least in the adjacent surf zone. Another band of heavy-rich sediments occurs just outside of and parallel to the surf zone, There is a pronounced seasonal variation in the percentage of heavy minerals, particularly on the beach foreshore, where the apparent abundance of heavy minerals increases during the winter when the beaches are cut back. A possible explanation for this apparent seasonal migration of heavy minerals lies in the transportation of light minerals fromthe beach foreshore to deeper water during the winter and back again during the summer. Since only surface samples were used in this study, deposition of light minerals results in apparent decrease in heavy mineral concentrations, and vice versa. The extreme variability in the amount of heavy minerals both with location on the beach and with time raises some question as to the inter- pretation of heavy mineral suites in beach and nearshore studies. Certainly, no simple relationship exists between the kind and amount of any particular mineral specie and its position on the beach. ORBITAL CURRENT METER During the last three months laboratory experiments for the evaluation of the coefficient of virtual mass have been completed. These experiments indicate that the instrument is sensitive to both drag and accelerative forces, but that in most instances the orbital velocity of wave motion can be interpreted without undue interference from virtual mass. DEFINITION OF DEPOSITIONAL ENVIRONMENTS It was thought that the following definitions, which were prepared by F, P. Shepard relative to investigation of sedimentation in the northern Gulf of Mexico for the American Petroleum Institute would be of interest in beach erosion studies. Accordingly, they are given below: Open Bay or Bight - A broad indentation between two headlands or points, the bays being sufficiently open so that waves coming directly into the bay are essentially the same in height near the center of the bay as on open portions of the coast. Hooked bay - Similar to the preceding but having only one headland. Estuary - A bay extending roughly transverse to the coast and having an outline similar to a typical river valley contour. Ecologically a great difference may exist depending on whether or not a stream enters the head of the estuary. 7 ac BAe \\ \] os KX x) #-° AMeram AS ANaOuRE sTwuRen AAVEH W10L 13232 w! 21V98 Sr 12234 WI S¥NOLNOD 6v6l asnonvy 922-2 S1WUY3SNIN AAV3H TVLOL 1°63 I 3ONVY w1ior v1 ALNlOd 38 Lagoon - A bay extending roughly parallel to the coast and separated from the open ocean by elongate marine deposits such as barrier islands. Open sound = A bay similar to a lagoon but with large openings between the protecting islands. Bottleneck bay - A pay with a narrow entrance which is guarded from waves by features other than barrier islands. Inlet - The narrow channel leading into a bay. Distributary - One of the channels formed by the dividing of the lower course of a river. River delta marsh = A marsh with brackish or fresh water found adjacent to the mouths of river distributaries. Tidal delta marsh - A salt marsh found around distributary patterns of tidal streams inside an inlet. Barrier islend marsh - A salt or brackish marsh found on the low inner margin of a barrier island. Open coast marsh - A salt marsh found along the open coast. Mangrove swamp - A salt or brackish marsh along the coast where there are abundant mangrove trees. This type could be further subdivided according to the type of mangrove. In the preceding definitions no attempt has been made to cover all cases and it is realized that many features will be borderline cases and thus hard to fit into the list which has been presented. The latter can always be given special descriptions to show that they lie between two types. Furthermore, it is important to add to the physiographic description of both bays and swamps the typical salinity and turbidity of the water. Using the definitions one can qualify a confusing local name as follows: "Cedar Bayou, an inlet into Mesquite Bay"; "Baptiste Collette Bayou, a small distributary of the Mississippi River",; "Graveline Bayou, an estuary along the Mississippi coast"; "Aransas Bay, a barrier bay inside St. Joseph Island"; Mississippi Sound, a barrier bay with rather large gaps between barrier islands;" "Blind Bay, a bottleneck bay in the lower Mississippi Delta"; and "Apalachee Bay, an open bay along the northwest coast of Florida". 1. Note that "barrier island" is used rather than "offshore bar" which has unfortunate connotations since it implies that the feature is submerged. 39 THE REFRACTION OF GROUPS AND OF THE WAVES WHICH THEY GENERATE IN SHALLOW WATER The paper, The Reflection of Groups and of the Waves Which They Generate in Shallow Water, was published in the Transactions, American Geophysical Union, Vol. 33, No. 4, August 1952. This work was sponsored by the Beach Erosion Board. An abstract of the paper follows: A process is described which may be of importance in beach and nearshore development and which may account for surging in the surf zone as well as other phenomena. It is shown how a group front may be refracted accord- ing to one law as it approaches a coast and then, after reflection, pro- ceed seaward under quite a different law. This permits the outgoing wave to move in a direction that it could not ordinarily attain, and causes "trapping" under many conditions. Stoneley's theory of refraction of energy fronts is further developed to permit quantitative investigation of group refraction on various types of shores. On the basis of the assumed hypothesis, the outgoing surf beat may be totally reflected from deep water, then reflected from the beach, a process which can occur re-= peatedly and result in newly arriving groups with varying phase relation- ships. Theory and techniques are developed for the investigation of the surf-beat path. The refraction of the reflected groups is shown to dis- play regions of high convergence, divergence, and reinforcement. NEARSHORE TEMPERATURE FLUCTUATIONS AT OCEANSIDE, CALIFORNIA Additional bathythermograph lowerings were made from Oceanside Pier on 9 July, and temperature fluctuations similar to those previously reported were found. The installation of a thermograph at Oceanside is under con- sideration. The resulting temperature records would permit comparison with Scripps Pier records for determination of any similarities in time of occurrence and duration of temperature fluctuations. WAVE INTENSITY ALONG A REFRACTED RAY A return has been made to this problem in order to try out another ap- proximate solution for the wave intensity along a single ray. The exact solution for the ray equation for the case of circular contours and a linear variation in wave velocity has been obtained. The stepwise use of the solution along a general ray over complex underwater topography is being investigated. TSUNAMI RECORDER The tsunami recorders at La Jolla and Oceanside worked satisfactorily throughout the entire period. On two occasions unusual disturbances were noted on the recording of the microbarogram, the wind direction, and the wind speed. These consisted of quite regular oscillations of approximately 7-minute period, lasting for several hours and with definite correlation between the three records. Inquiries reveal that no indication of these oscillations could be found on nearby seismographs. An attempt will be made 40 during the forthcoming quarter to interpret these oscillations. DECOMPRESSION GAGE Deep-sea divers must carefully schedule their ascents from deep dives in order to avoid decompression sickness. The Army and Navy have prepared tables for scheduling decompressing, but they are inconvenient, expecially in the case of self-contained diving where the diver must schedule his own dive. A handy wrist gage is being designed which will automatically take into account the time-depth history of the diver's dive and predict for him a safe, optimum rate of ascent. The problem is to make the characteristics of the gage as close as possible to the characteristics of the diver's body. This is being done by having the gage give, as close as it is possible to do with a simple mechanism, the same rate of ascent as standard diving tables. WIND STRESS WATER A technical report, Wind Stress Over Water, by William G. VanDorn, is being prepared. This work has been supported by contract with the Air Force. An abstract is included here because the paper has some bearing on beach erosion problems. The wind-induced slope of the surface of an 800-foot model-yacht pond has been measured to a relative accuracy of 5 x Gn) Thas slope, which is proportional to the sum of the surface and bottom stresses, is shown to be the result of two effects: first, a tangential "friction" drag, which is invariably present and proportional to the square of the Windspeed; and second, a "form" drag, which occurs only after the wind has increased above a certain critical value. The second effect is re- lated to surface waves. Application of a detergent to the water eliminates both waves and form drag. The surface current was proportion- al to the windspeed and independent of waves. The slope increased with heavy rain, and a theoretical model is proposed which adequately pre- dicts the observed increase. The present study was modeled closely after Keulegan's experiments in a 60-foot laboratory channel. The results of the two studies agree quantitatively. PUBLICATIONS Article Submitted for Publication Shepard, F. P., and D. B. Sayner, Longshore and Coastal Currents at Scripps Institution Pier, submitted to Beach Erosion Board. Articles Published Inman, D. L., Measures for Describing the Size Distribution of Sediments, Jour. Sed. Petrol. Vol. 22, No. 3, 1952, pp. 125-15. Al Inman, D. Lo, and W. H. Quinn, Currents in the Surf Zone, Proc. Second Conf. on Coastal Engineering, Houston, Texas, November 1951, Council on Wave Research, 1952, pp. 2-36. Williams, E. Allen, and John D. Isaacs, The Refraction of Groups and of the Waves Which They Generate in Shallow Water, Trans. Am. Geophys. Union, Vol. 33, No. h, August 1952. II. New York University Bi-Monthly Progress Report, (Extracts from the 16th and 17th Reports, dated ‘ September and 5 November 1952) Part Il of "A Unified Mathematical Theory for the Analysis, Propagation, and Refraction of Storm Generated Ocean Surface Waves" has been completed and distributed to those on the mailing list. It treats the problem of the refraction of a short crested Gaussian Sea Surface and gives some actual examples of the determination of power spectra by numerical and electronic techniques. Work for Part IIl (the final part of the paper) has been started. One excellent example which verifies the forecasting theory, as far as the variation in /i of the power spectrum, has been found and worked up from the literature. A paper entitied "The Theory of the Refraction of a Short Crested Gaussian Sea Surface with Application to the Northern New Jersey Coast," written by Willard J. Pierson, Jr., John J. Tuttell, and John A.Woolley, was presented by Mr. Pierson at the Third Conference on Coastal Engineering and will appear in the conference publication. Messrs. W. J. Pierson, W. Marks, and R. Schotland attended a conference sponsored by the Beach Erosion Board in Washington, D. G., on wave recording and wave analysis methods and alse discussed plans for next year with Board representatives. The next bi-monthly report will conclude the research conducted for the Board under the current contract, and will serve also as the final report of the project, summarizing the successes and failures of the project. JOLILS The Agricultural and Mechanical College of Texas, Quarterly Report for Period Ending 30 September 1952. Progress During the Quarter - 1 July to 30 September 1952 1. Five fairly extensive field trips, of about one week each, were made during July and August to the Atchafalaya Bay region. The purpose of these field trips was to accumulate wave data on friction and percolation losses in the vicinity of the Pure Oil Platform, known as structure A. During only one of these trips were the waves greater than one foot in height. During this trip the wave heights and periods were between 13 to 3 feet and 3 to 4.5 seconds respectively. One wave recorder was 42 operating on structure A, ad one was installed on structure B. Mechanical difficulty of the boat prevented the installation of the third recorder. Structure A is in a depth of water about 12 feet. Structure B is located 250 yards southwest of structure A and is in a depth of water of about 18 feet. The bottom slopes gently from A to B and consists of a gelatinous mud, particle size range between .00]1 mm and ,00) mm with a means particle diameter of .002 mm. The waves approached from the southwest, a direct line between structures A and B. Ze A tripod was built for mounting the third pressure head in the vicinity of an old abandonded lighthouse off point Au Fer Reef (depth of water about 7 feet). However, it has been decided that this installation was impracticable, since it would require an excessive length of cable to reach the pressure head installed outside the influence of the reefs. In- stead, since the waves are unusually low in this vicinity, plans have been made tO operate the wave recorder from the boat in conjunction with the pressure head mounted on the tripod. If this proves feasible, the range of operation will be increased. Plans for Third Quarter - 1 October to 31 December 1952 1. The wave records obtained during the second quarter will be analyzed. 2. Several extensive field trips will be made to the Atchafalaya Bay region to accumulate additional wave data on friction and percolation losses. 3. One wave recorder will be installed permanently on structure B. Structure B is conveniently accessible from structure A without having to rent a boat. he The third wave recorder will be installed at temporary sites shore= ward and seaward of structures A and B respectively. This will necessitate the renting of a boat, as was done during the second quarter. At the shore- ward site of structure A the tripod for the pressure head will be used, and the recorder will be operated from the boat. At the seaward site of structure B, a structure in deeper water, where sandy bottom exists, will be used. ABH Waterways Experiment Station, Vicksbur Mississi Report for Quarter ending 30 September 1952. alt Model Study of the Effects of Tidal Inlets on Adjacent Beaches - Three tests involving stability of the unbroken beach for a tide range of 0.1 feet, a tidal cycle of 20 min.. a wave height of 0.1 feet, and a wave H/L ratio of 0.025 were completed. An inlet having a bottom width of 2.0 feet and a depth cf 0.2 feet at mean tide level was cut through the beach following stability for each test, and the cycle of operation repeated. The inlet closed completely during the second phase of each test, in~ dicating that the rate of littoral drift produced by the test 43 Quarterly waves was greater than could be removed from the inlet by the tidal currents. 2. Wave Run-Up on Shore Structures - Preparation of the first interim report, a revised testing program, and cost and time estimates were completed and forwarded to the Beach Erosion Board. Testing was deferred pending ap- proval of the revised testing program and cost and time estimates. The results of tests described in the first interim report (test data for a vertical-faced monolithic seawall) show that the volume of overtopping water and height of wave run-up vary with both wave height and length. The variation is discontinuous. The volume of over-topping water and height of wave run-up vary in cycles from minimum to maximum and increase as wave height and wave length increase. Ve Beach Erosion Board, Research Division, Project Status Report for Quarter ending 31 December 1952. In addition to the research projects under contract to the various institutions which are reported on above, the Research Division of the Beach Erosion Board is carrying out certain projects with its own facilities. The main projects were described in the last Bulletin (October 1952) and a short description of the work accomplished through the last quarter is given below. Study of Effects of Tidal Fluctuations on Wave Produced Beach Profiles - The priority projects which had interrupted work on this project have been completed, and the 85 foot concrete indoor tank is being converted back to its original condition for the completion of these tests, The resumed test schedule will nee the remainder of tests for a l-hour tidal cycle with 0.50 and 0.25 feet tidal range; thereafter eetne will be made on l-hour tidal eycles with 0.50 and 0.28 feet tidal range Stag of Quantity of Sand in Suspensibn in Coastal Waters (in two i ta Part 1. Laboratory development of a suspended sediment sampler for use in studies of sand transport by wave action - The report on this phase of study has been completed and is under review for possible publication. Part 2. Field investigation of suspended sediment in surf zone at Mission Bay, California - The report on this field investigation has been completed and is under review by the staff. A suspended sediment sampler, auxiliiary parts, instructions for operation and maintenance, etc., were shipped te Scripps Institution of Oceanography for use on similar work. Correlation of Effectiveness of South Lake Worth (Florida) Inlet By- Passing Plant with Rate of Drift Reaching Plant - The field data on this* study are being analyzed and areport is in preparation. Preliminary analysis of a portion of the collected data indicates that a relationship between wave energy and material pumped by the by-passing plant can be developed for the period of observation. The procured sand samples are being studied in an effort to correlate the material movemant with sediment characteristics. 44 It is estimated that this project report is approximately 60 per cent complete. Study of Wind Set-up and Wave Generation in Inland Waters - Arrangements are being made for additional laboratory study, probably by contract. Preparation of Reports Based on Mission Bay Field Data - A report on the probable magnitude of the errors involved in hydrographic surveying was pre-= sented at the Coastal Engineering Conference at MIT in October. Additional data on the error to be expected with lead line sounding is being analyzed, and will be incorporated in the final report. Statistical Wave Data on the Great Lakes = A report is being prepared on the data compiled for Lake Michigan and should be published early in 1953. The report will include an example showing how shallow water data at any point may be cbtained from the hindcast data at the five stations. Analysis of weather charts for the same three years (198-1950) has been initiated for the stations on Lake Ontario (Hamilton, Ontarios Rochester, N. Y.; Stony Point, Ne Ye) Statistical Data on the North Atlantic Coast ~ The three years of data obtained from the weather charts for each station is being compiled into a form suitable for engineering usage. = Wave Tank Study of Wave Energy Loss by Bottom Friction and Percolation = A report on the test results has been completed and is undér review by the staff. Study of Parailel Lines Method for Detecting and Measuring Wave Trains ~ Further work is in progress to determine the applicability of the method for practical use. The study of aerial photos is being continued, using the parallei line method to separate out the wave trains as a means of assessing the value of the method. Use of Raleigh Disc_as Wave Direction and Force Indicator - Study has been made of various damping systems and pressure celis for use with the Raleigh disc, and the component parts for a sensitive type pressure gage have been ordered. It isi believed this gage, when assembled, will record the very small pressures caused by the water motion. While awaiting delivery on these parts, a Rayleigh disc and damping system is being assembled, and will be tested initially without the pressure cell. Effect of Cylindrical Obstacles on Waves Passing Around Them = The tests have indicated that the energy distribution behind cylindrical obstacles can be predicted very closely by diffraction theory, at least for cases where the distance between obstacles is many times the obstacle diameter. The tests have shown the disirability of having the pipe supports in the ccast model basin not exceed 1 inch in diameter, and this size has been chosen for use there. Study of Methods of Sand Analysis by Sett, ing Tubes - Correspondence to other agencies concerning methods of sand size analysis applicable to beach 45 sands was undertaken. The pressure cells ordered for the Rayleigh disc direction and force indicator are being considered in connection with the Beach Erosion Board manometric settling tube. An kmery settling velocity tube has been constructed and set up for laboratory use, and a more complete unit is being ordered from the Federal Inter-Agency Sub-committee on Sedimentation. Correlation of Waves and Longshore Currents - The extensive (twice daily observations at three points along Mission Beach for a year and a half) longshore current data is being arranged in a usable form for statistical and analytic analysis. It is hoped that analysis of this data with the simultaneous observations of waves, winds, tides, rips, etc., may lead to a better method of current prediction---or at least to a means of telling the error (or variability) that may be involved in present prediction methods. Equilibrium Profile of Beaches = The report on this study has been com= pleted and is under review by the staff. Study of Effects on Beach Profile of Varying Wave Periods - The report on this study has been completed and is under review by the staff. 46 BEACH EROSION STUDIES Beach erosion control studies of specific localities are usually made by the Corps of Engineers in cooperation with appropriate agencies of the various States by authority of Section 2 of the River and Harbor Act ap- proved 3 July 1930. By executive ruling the costs of these studies are divided equally between the United States and the cooperating agencies. Informtion concerning the initiation of a cooperative study may be obtained from any District or Division Engineer of the Corps of Engineers. After a report on a cooperative study has been transmitted to Uongress, a summary thereof is included in the next issue of this bulletin. A summary of reports trans- mitted to Congress since the last jssue of the Bulletin and list of authorized cooperative studies follow: SUMMARIES OF REPORTS TRANSMITTED TO CONGRESS CALIFORNIA, CARPINTERIA TO POINT MUGU The area studied comprises the Pacific Ocean shore line of California from Sand Point to Point Mugu, a length of 38.5 miles. This stretch of shore lies in Santa Barbara and Ventura Counties. The principal communities along this shore are Ventura and Port Hueneme, both in Ventural County, and their populations are about 16,500 and 3,000 respectively, with increases of 10 to 20% during the summer. The population of Ventura and Santa Barbara Counties is about 211,000. The San Fernando Valley in Los Angeles County within about 50 miles of the Ventura beaches and having a population of nearly 1/2 million contributes considerably to beach use in the area. The terrain adjacent to the shore suggested division of the study area into two major subdivisions as follows: a. Sand Point to Ventura River - This portion of the study area com- prises about 17 miles of generally rugged shore extending in a general northwest-southeast direction along the foot of the Santa Ynez Mountains. 47 The coastal area is drained by a number of short, steep, intermittent streams which contribute sand and gravel to the shore during floods. The coast highway and the railway generally parallel the shore at the foot of the erosion resistant sea cliffs. The coastal plain is very narrow except for the Carpinteria plain with a maximum width of 2 miles and length of about h miles at the upcoast end of the area. A State beach park has been developed at Carpinteria. The development of the shore area in the remainder of this section is relatively minor. Three short sections of shore are publicly owned and are used for park purposes. Although most of the shore of this area has been reasonably stable during historic time, encroachment of the highway on the beach has necessitated its protection by seawalls and groins. b. Ventura River to Point Mugu - This portion of the coast comprises about 21.5 miles of shore extending generally in a northwest-southeast direction. The coastal plain includes the deltas of the Ventura and Santa Clara Rivers, which bring large quantities of materials to the shore, especially during flood periods. It gradually widens from the mouth of the Ventura River into the broad, flat Oxnard Plain, The Ventura-Pierpont Bay shore, lying between the mouths of the Ventura and Smta Clara Rivers is publicly owned or is in process of acquisition for park purposes. This stretch of shore line alternately advances and retreats due to the irregularity of supply of material by the Venture and Santa Clara Rivers. This instability limits the development of this shore area, The jettied entrmce to Port Hueneme lies about midway between the Santa Clara River and Point Mugu. The jetties have caused accretion to the west and erosion east of the entrance. The erosion east thereof and recommendations for remedial measures have been covered by a recent report on Port Hueneme and therefore were omitted from the present study. The tides in the area are diurnal, the diurnal range being 5.3 feet and the mean range 3.7 feet. The principal wave action affecting the area is from the west and northwest. The direction of predominant littoral drift is downcoast (southeastward). A relatively constant supply of material, estimated at 250,000 cubic yards annually, arrives at the problem area by littoral movement along the shore from northwest of Ventura River. The large quantities of material supplied at irregular intervals during floods by the Ventura and Santa Clara Rivers cause variations in the position of the shore line in the Ventura problem area. The shore line in this area since 1855 has been seaward of its position in that year, but, in general, it has receded since 1927. Investigations of shore waters in the Carpinteria area since 197 have indicated sewage pollution in this area and resulted in closing a portion of the beach. Planning is in progress for a new treat- ment plant which may be expected to remedy this condition. Although the Ventura sewage treatment plant operates satisfactorily, some contamination of the ocean waters occurs after high stages in the Ventura and Santa Clara Rivers. The district engineer developed a plan for protecting the shore at Ventura. He made an economic analysis of the proposed work and found that benefits from prevention of loss of beach area, creation of additional land 48 surface, and savings in automobile travel justify the work. He concluded that since the shore to be improved and protected is publicly owned, Federal par- ticipation to the extent of one-third of the cost of the groin construction would be justified. After reviewing the report of the district engineer, the State Lands Commission indicated its belief that a statement regarding ownership of land in the report was adverse to the interest of the State of California. In that connection, the Beach Erosion Board stated its position that nothing in the report, or in any action taken with respect thereto, should prejudice in any way the respective claims of the United States and the State of California in regard to the status, as open sea or inland waters, of that portion of the submerged lands to be filled as a result of the construction of the project, that question then being one of the matters before the Supreme Court in pending supplemental proceedings in the case of the United States v. State of California, No. 1], Original. In accordance with existing statutory requirements, the Beach Hrosion Board stated its opinion thats a. It is advisable for the United States to adopt a project authorizing Federal participation in the cost of shore protection at Ventura, California; b. The entire interest involved in the proposed protective measures is public. It is associated with increased earning power of public property, new public property created, sayings in automobile travel and unevaluated welfare benefits to the general public; ¢. The share of the expense which should be borne by the United States is one-third of the first cost of the recommended groin construction. The Federal share was estimated at $53,150. The Beach Erosion Board recommended that a project be adopted by the United States authorizing Federal participation by the contribution of Federal funds in an amount equal to one=third of the cost of construction of 3 groins fo: the protection of the shore at Ventura, California, substantially in accordance With the plan developed by the district engineer, the initial construction to consist of one groin, the other two to be deferred pending demonstration of the need thereof. Federal participation was recommended subject to the con- ditions that responsible local interests wills a. Adopt the foregoing plan of protection; b. Assure maintenance of the protective groins during their use- ful life, as may be required te serve their intended purpose; ec. Provide at their own expense all necessary lands, easements, and rights-of-way required for construction; 49 d. Hold and save the United States free from damages arising from the construction and maintenance of the project works; e. Control water pollution in the areas where beaches are to be improved to the extent necessary to safeguard the health of bathers; f. Assure continued public ownership of the beaches and their administration for public use only. The Board further recommended that the adequacy of work proposed by local authorities, detailed plans, specifications, assurances that the requirements of local cooperation will be met, arrangements for prosecuting the entire project be approved by the Chief of Engineers prior to commence- ment of work. The Board also recommended that all agencies concerned give full consideration to the effects on the downcoast shore of any littoral 0 barriers between Carpinteria and Point Mugu prior to undertaking such works, and, if warranted, make adequate provision for by-passing littcral material at such barriers. The amount of Federal participation in accordance with the foregoing recommendation was estimated at 20.250 for the initial construction consisting of one groin and $53,150 if all three groins are required. CONNECTICUT = PAWCATUCK RIVER TO THAMES RIVER The area of the State of Connecticut studied comprises the shores of Little Narragansett Bay and Fishers Island Sound between the mouths of Pawcatuck River and Thames River. It includes the shores of the Towns of Stonington and Groton, a total length of about 31.5 miles. This shore area is adjacent to and east of New London, Connecticut, and is about 130 miles east of New York City. It is developed to a minor extent as a resort and residential area. The permanent population of the two towns is about 21,000. The summer population is about 20 per cent greater. The United States owns the shore at Avery Point, the location of a Coast Guard Training Station. The State of Connecticut owns Barn Island Waterfowl area on Little Narragansett Bay and Trumbull Airport on Poquonock River, and there are several small publicly owned beaches included in the area. Fishers Island Sound is part of Long Island Sound, located at the north side of the eastern entrance thereof. Tides are semidiurnal, and their mean range is 2.6 to 2.7 feet. The spring range is 3.1 to 3.2 feet. The maximum tide of record was about 8.5 feet above mean high water. Tides 3 feet or more above mean high water occur about once a year. With a tidal stage of 3 feet above mean high water, the maximum height of breakers land- ward of the lowwater line is about .5 feet. Larger waves can reach the shore only during infrequent higher tides. Due to the limited size of Fishers Island and Long Island Sounds, the only waves of importance are those generated in the sounds. The movement of material by wave action is diverse in character. Ordinary short storm waves cause littoral movement and offshore loss of beach material. Absence of swells in most of the area probably precludes the possibility of return of material from offshore by wave action. 50 Along shores which are aligned generally in a north-south direction, the pre- dominant littoral drift is northward. Due to the irregularity of the shore characterized by numerous indentations and projections, there is no general littoral movement either eastward or westward. Movement of material along shores aligned generally in an east-west direction is largely influenced by the direction of the maximum lengths of open water fronting these shores, over which waves can be generated. The study area is characterized by headlands of unconsolidated glacial material with numerous rock outcrops, between some of which wave-built bars have been formed and the landward areas generally have filled and become marshy. The headlands formerly supplied ample material to the intervening beaches, but the headlands are now generally rocky or are protected by sea- walls and revetments. The supply of material is thus reduced or eliminated ana consequently the beaches have slowly deteriorated. Groins have been found to be capable of causing minor accretion areas and stabilizing a narrow band along the upper portion of the beach, but the natural supply of material is generally insufficient for the formation of adequate protective beaches by groins alone. The building and maintenance of adequate beaches may be accomplished by artificial placement of sand. The rate of loss of fill can be reduced by groins. The Beach Erosion Board concluded that the best plans for the protection and improvement of beaches within the study area were as follows: a. West View - Direct placement of a sand beach in front of seawalls and cottages, and construction of an impermeable groin at the west limit of the ifslibe b. Jupiter Point - Construction of a dumped riprap mound in front of the cottages along the west side of Jupiter Point; and c. Eastern Point Beach Park - Direct placement of sand along the narrow west end of the bathing beach and enlargement of the impermeable groin at the east limit of the park. the Board stated that the improvement of Eastern Point Beach Park ap- peared to be justified by evaluated benefits, but concluded that the limited public interest other than recreational, involved in the improvement, the local character of the public interest and the minor Federal aid for which the project would be qualified do not warrant adoption of a Federal project for protection of this area. The Board believed, however, that local interests should review carefully the benefits estimated by the Division Engineer for protective and improvement measures considered and should determine for them- selves the economic justification for undertaking those works as local pro- jects. As existing Federal law does not include a policy of Federal aid in protecting privately owned shores, no Federal participation was recommended by the Board in the cost of other work considered. In accordance with existing statutory requirements, the Board stated its opinion that: owl a. It is inadvisable for the United States to adopt projects authorizing Federal participation in the cost of protecting and improving the shores within the area studied ; b. The public interest involved in the proposed improvements for these shores is small; and c. No share of the expense should be borne by the United States. The Board recommended that. no project be adopted by the United States at this time authorizing Federal participation in the cost of measures for the protection and improvement of the shores within the area covered by this report. OHIO SHORELINE OF LAKE ERIE = SANDUSKY TO VERMILION The area studied is located in Erie County on the south shore of Lake Erie from about 27 to 57 miles west of Cleveland, Ohio. It lies between Cedar Point at the entrance to Sandusky Bay and Vermilion River, a distance of about 20 miles. Sandusky Bay, Vermilion Harbor and Huron Harbor, the latter located at the mouth of Huron River near the center of the study area, have all been improved by the United States for navigation. Erie County had a population of about 3,200 in 190. The cities of Sandusky and the lake front townships in the study area had a combined population of about 32,000 with an estimated increase of 250,000 vacationists during the summer months. The property along the shore line of the studv area has been developed mainly for private residential. agricultural md recreational purposes. Inland areas are devoted mainly to the agricultural uses. The shore is publicly owned at the Huron Waterworks and the State Roadside Park at Huron. These publicly owned properties are adequately protected by seawalis. They have no beaches nor bathing facilities. Beaches suitable for recreational use are located at Cedar Point and east of Huron Harbor. The pumping station at the Plum Brook Ordnance Works is a Federal installation, and is in need of further protection. Pollution found in water samples taken at the mouths of Huron and Vermilion Rivers in 1950 indicate that use of the intervening shore for bathing would be inadvisable. No apparent hazards from sewage contamina-= tion were found in lake waters along the Cedar Point Beach. \ The westerly 7.5 miles of the study area consists of a low lying barrier beach, separating Sandusky Bay and adjoining swamp land from Lake Erie. In general the beach is composed of fine sand moved westward by littoral currents from the eroding shores to the east. The shore line of the remainder of the study area consists principally of eroding biuffs of clay, silt, and sand varying from 10 to 30 feet in height with little or no beaches, except where littoral drift has been arrested by structures. Shale outcrops near low lake level appear northwest of Huron. It has been estimated that about 10 per cent of the bluff material is suitable for beach building. Bast of the Huron River and the Sandusky Bay entrance good beaches have formed by accretion caused by the jetties at the east sidesof these entrmces. The study area is divided into two parts by the harbor structures at Huron, and the entire area is separated from adjacent areas by structures at Vermilion Harbor to the east and the Sandusky Bay East jetty to the west. Material 52 for beach building cannot enter the area from either the east or west nor pass Huron Harbor in any appreciable quantity. Miscellaneous groins and walls have been constructed in an attempt te prevent erosion of the shore. Short groins have generally caused minor accretion on their east sides and have reduced recession of the bluffs to some extent. The accretion east of the jetties at Cedar Point and Huron Harbor indicates a westward predominance of littoral drift. The mean lake level for the months of April to November is about 1.7 feet above the established low water datum. The highest lake stage and the highest monthly mean recorded at Cleveland, Ohio, are respectively about 5 and ) feet above low water datum. Storms cause sharp changes in lake levels as winds move the water toward the ends of the lake. The greater fetch and movement of winds affecting the area are from the northeasterly quadrant, and because the area is near the western end of Lake Erie, it is estimated that, considering the effect of wind set up during easterly storms, the lake could reach a level in the study area of about 6.5 feet above low water datum. During a northeast storm waves may range up to 10 or 12 feet in height in deep water, but ordinarily waves of this height would break before reaching shore structures. The maximum wave height that need be considered in designing structures where no protective beach will remain is probably 5 feet. Existing groins with shore ends from about 6 to 10 feet above low water datum indicate that these elevations are generally adequate to impound a low protective beachwWerre a supply of sand by littoral drift is available. In the Cedar Point area the alignment of the shore line is such that it is exposed to a more direct approach of waves generated by winds of longer fetch than is possible at other points, and the beach is the only protection to the highway; therefore protection should be provided against wave action to a height of 10 feet above low water datum. For the remainder of the study area an elevation of 6 feet for the shore end of groins should be used. Ice forms a protective coating over beaches during winter months, but the lifting and battering action of shifting ice floes during the spring breakup must be considered in designing shore structures for structural stability. The district engineer developed plans for protecting and improving the shores of the study area, and concluded that the most suitable plan of improve- ment for the portion of Cedar Point westerly of the New Entrmce Road would be the artificial placement of fill to restore eroded beaches and construction of groins to reduce the rate of loss of the fill, with the groin construction deferred until it could be determined by maintenance experiance that their construction would reduce annual cost. He considered that the shore from Huron Harbor to Old Woman Creek could also be maintained by artificial nourishment, if cooperative action by owners could be obtained, otherwise an individual owner could protect his property by groins. He further concluded that for the remainder of the problem area, the most suitable methods of stabilizing the shore line include the protection of an existing or artificially created beach by groin construction and protection of the bluff by a seawall or stone revetment, selection of the method to be based upon the proposed use of the property. He also concludéd that the publicly owned Huron Waterworks and State Roadside Park properties are adequately 28) protected at the present time, that protection of the Fedérally operated Plum Brook Ordnance Works pumping station should be undertaken by the Federal agency controlling the property, and that no Federal interest is involved in any of the plans of improvement ffor private property. As aresult of an investigation of underwater sand and gravel deposits in the vicinity of Lorain and Fairport Harbors, the district engineer found that sand suitable for beach building is available in quantities in excess of amounts needed for recommended improwement of beaches along the Chio shore line. The district engineer recommended that owners of private property adopt the plan of improvement considered best suited to the immediate area and its desired utilization and further recommended that continuous sections of shore be protected at one time where justified by local benefits with no Federal participation in the cost of the improvements. The Beach Brosion Board stated that the area under consideration was the subject of areport by the Board in 191 and that the current report was initiated at the request of the cooperating agency primarily to develop plans suitable for protecting shorter reaches of shore frontage, since coordinated action of the many owners involved on the previously recommended plan had not been effected. The Board was still of the opinion that artificial nourishment by placement of a supply of material at the east end of each section, Vermilion to Huron or Huron to Cedar Point, would be the most effective and economical comprehensive plan for protecting and improving either complete section and should be tested before resorting to a bayhead beach system including groins, but stated that the method of artificial nourishment could also be used for smaller sections by placing material at the east limit of the section. The plans considered most suitable by the district engineer for the Cedar Point section and for the section from Huron Harbor to Old Woman Creek are extensions of this principle. The Board concurred in the conclusion of the reporting officers that the most suitable comprehensive plan of improvement for the Cedar Point area westerly from the New Entrance Road is restoration of eroded beaches by artificial placement of sand and construction of groins to reduce the rate of loss, with the groin construction deferred until it is determined by observation that annual maintenance costs without groins are great enough to justify their construction. However, the Board considered it unlikely that a plan of maintenance by the feeder beach method without groins would have higher annual costs than the combined plan of fill and groins. The Board's opinion that groins probably will not be justified for the Cedar Point area did not imply that groins will not be needed where short frontages are protected by individual owners. In those cases where the natural supply from littoral drift is small, the losses should be expected to be relatively large without adequate groins. In view of the probable high rate of loss and the high unit cost of sand fill for the small quantities involved, the Board concluded that groins would be essential prior to placement of fill. At the request of the cooperating agency, other plans of protection were developed by which individual owners can protect shorter lengths of shore. These plans com- prise groins to improve or retain existing or artificially filled beaches, or seawalls or revetments where beaches are not required. The Board con- curred in those plans, but pointed out that existing meager littoral drift a4, will be reduced as more protective works are installed, so that inclusion of artificial placement of fill would generally be desirable in connection with groin construction, Even though the foregoing plans can be used for relatively short frontages, the Board emphasized the desirability of coordinated action by owners to protect longer stretches of frontage under any plan of protection, and the necessity of adequately protecting the ends of the work to prevent flanking. The Board recommended that privage owners consider adoption of the plans of protection presented by the district engineer, based upon their own determination of economic justification, selecting that most suitable to the present condition and desired use of their shore frontage, consistent with the effect on adjacent shore sections. As non-Federal publicly owned shores did not require additional protection at the time, and existing Federal law includes no policy for Federal assistance in the cost of protecting privately owned shores, no project authorizing Federal participation in the cost of the work was recommended. In accordance with existing statutory requirements, the Board stated its opinion that: a, it is not advisable for the United States to adopt a project authorizing Federal participation in the cost of protecting and improving the Lake Erie shore of Ohio within the area studied; b. No public interest is involved in the proposed improvements; and c. No share of the expense should be borne by the United States. 55 AUTHORIZED COOPERATIVE BEACH EROSION STUDIES NEW HAMPSHIRE HAMPTON BEACH. CGooperating Agency: New Hampshire Shore and Beach Preservation and Development Commission Problem: To determine the best method of preventing further erosion and of stabilizing and restoring the beaches, also to determine the extent of Federal aid in any proposed plans of protection and improvement. MASSACHUSETTS PEMBERTON POINT TO GURNET POINT. Cooperating Agency: Department of Public Works. Problem: To determine the best methods of shore protection, prevention of further erosion and improvement of beaches, and specifical- ly to develop plans for protection of Crescent Beach. The Glades, North Scituate Beach and Brant Rock. CONNECTICUT STATE OF CONNECTICUT. Cooperating Agency: State of Gonnecticut (Acting through the Flood Gontrol and Water Policy Commission) Problem: To determine the most suitable methods of stabilizing and improving the shore line. Sections of the coast are being studied in order of priority as requested by the cooperating agency until fhe entire coast has been included. NEW JERSEY STATE OF NEW JERSEY. Cooperating Agency: Department of Conservation and Economic Development. Problem: To determine the best method of preventing further erosion and stabilizing and restoring the beaches, to recommend remedial measures, and to formulate a comprehensive plan for beach preservation or coastal protection. NCRTH CAROLINA CAROLINA BEACH. Cooperating Agency: Town of Carztolina Beach. Yroblem: To determine the best method of preventing erosion of the beach. FLORIDA PINELLAS COUNTY” Cooperating Agency: Board of County Commissioners. 56 Problem: ‘To determine the best methods of preventing further re- cession of the gulf shore line, stabilizing the gulf shores of certain passes, and widening certain beaches within the study area. tes E TEXs GALVESTON COUNTY. Cooperating Agency: County Commissioners Court of Galveston Gounty. Problem: To determine the best method of providing a permanent beach and the necessity for further protection or extend- ing the sea well within the area bounded by the Galveston South Jetty and Hight Mile Road. To determine the most practicable and economical method of preventing or retarding bank recession on the shore of Galveston Bay between April Fool Point and Kemah. CALIFORNIA STATE OF CALIFORNIA. Cooperating Agency: Division of Beaches and Parks State of California erosion and Calafornial. a Problem: To conduct a study of the problems of beach shore protection along the entire ee of ar The current study covers the Santa Cru e WISCONSIN KENOSHA. Cooperating Agency. City of Kenosha. Problem: To determine the best method of shore protection and beach erosion control. OHIO STATE OF OHIO, Cooperating Agency: State of Ohio (Acting through the Superintendent of Public Werks) Problem: To determine the best method of preventing further erosion of and stabilizing existing beaches, of PESO Ee and creat- ing new beaches, and appropriate locations for the develop- ment of recreational facilities by the State along the Lake Erie shore line. Sections of the coast were studied in order of priority as requested by the cooperating agency. Only study remaining to be completed includes the shore from Euclid City to Chagrin River. Bit) TERRITORY OF HAWATI WAIMEA & HANAPEPE, KAUAI. Cooperating Agency: Board of Harbor Commissioners, Territory of Hawaii. : Probiem: To determine the most suitable method of preventing erosion, and of increasing the usable recreational beach area, and to determine the extent of Federal aid in effecting the desired improvement. 58 i a oN c a3) yaa TULL ea ean