He rally wae Z Res. Ctr WHOI CETA@ 80-8 DOCUMENT COLLECTION Estimation of Flow Through Offshore Breakwater Gaps Generated by Wave Overtopping by William N. Seelig and Todd L. Walton, Jr. COASTAL ENGINEERING TECHNICAL AID NO. 80-8 DECEMBER 1980 Approved for public release; distribution unlimited. aa U.S. ARMY, CORPS OF ENGINEERS ae. COASTAL ENGINEERING) ee | RESEARCH CENTER Kingman Building no, 0-F Fort Belvoir, Va. 22060 Reprint or republication of any of this material shall give appropriate credit to the U.S. Army Coastal Engineering Research Center. Limited free distribution within the United States of single copies of this publication has been made by this Center. Additional copies are available from: National Technical Information Service ATTN: Operations Division 5285 Port Royal Road Springfield, Virginia 22161 The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) READ INSTRUCTIONS REPORT DOCUMENTATION PAGE BEPREAD INSTRUCTIONS 1. REPORT NUMBER 2. GOVT ACCESSION NO.| 3. RECIPIENT'S CATALOG NUMBER CETA 80-8 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED ESTIMATION OF FLOW THROUGH OFFSHORE BREAKWATER GAPS GENERATED BY WAVE OVERTOPPING Coastal Engineering Technical Aid 6. PERFORMING ORG. REPORT NUMBER 8. CONTRACT OR GRANT NUMBER(s) 7. AUTHOR(s) William N. Seelig Todd L. Walton, Jr. 10. PROGRAM ELEM AREA & WORK U NT, PROJECT, TASK IT NUMBERS 9. PERFORMING ORGANIZATION NAME AND ADDRESS Department of the Army Coastal Engineering Research Center (CERRE-CS) Kingman Building, Fort Belvoir, Virginia 22060 CONTROLLING OFFICE NAME AND ADDRESS Department of the Army Coastal Engineering Research Center Kingman Building, Fort Belvoir, Virginia 22060 14. MONITORING AGENCY NAME & ADDRESS(if different from Controlling Office) = N F31538 12. REPORT DATE December 1980 13. NUMBER OF PAGES 21 15. SECURITY CLASS. (of this report) UNCLASSIFIED DECL ASSIFICATION/ DOWNGRADING SCHEDULE 15a, 16. DISTRIBUTION STATEMENT (of this Report) Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, if different from Report) 18. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue on reverse side if necessary and identify by block number) ‘Breakwaters Wave height Wave period Offshore breakwaters Wave overtopping Waves 20. ABSTRACT (Continue on reverse side if necesaary and identify by block number) } 2 This report presents a method for estimating the net flow through the gaps of offshore segmented breakwaters caused by wave overtopping of the breakwaters. The method was developed so that either monochromatic or irregular waves can be specified. Example problems illustrate the effects of wave height and period, breakwater freeboard, spacing between breakwaters, and shore attachment on the flow rate. Computations may be done manually or by using the computer program, BWFLOW2, available from the Corps of Engineers Computer Library, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi. DD , FORM 1473 EDITIow OF 1 Nov 65 IS OBSOLETE TAN 72 UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) ; eshte ey vt ath ining helsay ah npeorag, 71 = : i le Gry ‘ a ee = heal starter a, TH if 7 ' ° i a 1 a! } i] \ La 0 ee a TL dL sees tied Ne ne y ‘we : yt com ater ip =n. — ieee shail —_ —, a» : ’ o : a eee feet! TF My bonny . = awe te ee i oe “ys ’ eee wv Oe tvin sie ASK ite eH pe See pi r iJ u », iy i ee ee : ne Nicer ink vy [to eyun aha in v/a wi jeden ae + we, aso an eh 1 ta day wow wie ya 04 TAD pytiy af ight De od MAb vere seraks heraog tiie a tel rc ce piblind had , ye a&t 16) goemayra ve Rani ‘ea Va TOF a ee | Par “AOVAG tir vg abe, o wy aki we. utr A) \ native “rn ey Nelle Set a PSO i es way e ar) PREFACE This report describes a method for estimating the flow rate through the gaps of offshore segmented breakwaters caused by wave overtopping. Factors that can be investigated using this method are the influence of breakwater freeboard, wave height and period, breakwater length and spacing, number of breakwaters, distance offshore, water depth at the breakwater, and shore attachment on the flow rate. Other wave effects on hydraulics, such as diffraction, refraction, reflection, and wave-current interactions, have not been considered. The work was carried out under the offshore breakwaters for shore stabilization and evaluation of shore protection structures programs of the U.S. Army Coastal Engineering Research Center (CERC). The report was prepared by William N. Seelig and Dr. Todd L. Walton, Jr., Hydraulic Engineers, under the general supervision of Dr. R.M. Sorensen, Chief, Coastal Processes and Structures Branch and Dr. J.R. Weggel, Chief, Evaluation Branch. Comments on this publication are invited. Approved for publication in accordance with Public Law 166, 79th Congress, approved 31 July 1945, as supplemented by Public Law 172, 88th Congress, approved 7 November 1963. ED E. BFSHOP Colonel, Corps of Engineers Commander and Director IIL 10 CONTENTS CONVERSION FACTORS, U.S. CUSTOMARY TO METRIC (SI) . SMMIBOLES ANNO) DIIMIMERONS, 56 6 6 69 6 60500 0000 IGNALOWDIOKCTEWOW 5 95 a 6 Go Oo oO O 0 0 ONG 0 0 0 GO 6 0 HYDRAULICS OF DETACHED BREAKWATERS. . ...-.. . -» 1. Enclosed Breakwater Systems ........ .- 2. Offshore Breakwaters with Gaps. ...... - ID VAMP, TROIS 5 5 6 06 590 6 5 6 Oo Go 0 060 oO DIO SUMMARY AND CONCLUSIONS . . ....-:....4.c4 © TAI VOI (IMDS 6 6 6 60000000 OOo OO 8 TABLES Computer program input for example problem 2... . Computer program output for example problem 2... . FIGURES Definition sketch. . ~~... +--+ «© + s+ s+ 2 ee eee Overtopping parameters, oa and Qs > riprapped 1:1.5 structure slope on a 1:10 nearshore slope ........ . - Ponding levels for porous multilayered breakwaters . An offshore breakwater system. . . . . « « » «= «= « « Dimensionless velocity as a function of K..... Design conditions for example problem 1. ..... . Effect of breakwater freeboard and gap spacing on V. Effect of incident wave height and gap spacing on V. Effect of wave period and PapEspacine mon ViEem iment Effect of shore attachment and gap spacing @m Woo 6 Page iL7/ 18 20 20 CONVERSION FACTORS, U.S. CUSTOMARY TO METRIC (SI) UNITS OF MEASUREMENT U.S. customary units of measurement used in this report can be converted to metric (SI) units as follows: Multiply ; by To obtain inches 25.4 millimeters 2.54 centimeters square inches 6-452 square centimeters cubic inches 16.39 cubic centimeters feet 30.48 centimeters 0.3048 meters Square feet 0.0929 square meters cubic feet 0.0283 cubic meters yards 0.9144 meters Square yards 0.836 square meters cubic yards 0.7646 cubic meters miles 1.6093 kilometers Square miles 259.0 hectares knots 1.852 kilometers per hour acres 0.4047 hectares foot-pounds 1.3558 newton meters millibars 1.0197 x 10 3 kilograms per square centimeter ounces 28.35 grams pounds 453.6 grams 0.4536 kilograms ton, long 1.0160 metric tons ton, short 0.9072 metric tons degrees (angel) 0.01745 radians Fahrenheit degrees 5/9 Celsius degrees or Kelvins! 1To obtain Celsius (C) temperature readings from Fahrenheit (F) readings, use formula: C = (5/9) (F -32). To obtain Kelvin (K) readings, use formula: K = (5/9) (F -32) + 273.15. Qn ZA td O Ol t=) SYMBOLS AND DEFINITIONS cross-sectional flow area of gap between breakwaters cross-sectional flow area between breakwaters and shoreline empirical runup coefficients breakwater gap width discharge coefficient for breakwater gaps discharge coefficient for space between breakwaters and shoreline water depth at the toe of the structure breakwater freeboard = h - ds acceleration due to gravity wave height at the structure equivalent deepwater wave height significant wave height at the structure structure height difference in mean water levels inside and outside of breakwaters a dimensionless parameter deepwater wavelength breakwater length log e number of breakwaters _ ponding level mean net flow rate through a breakwater gap or inlet net inflow by overtopping of a breakwater empirical overtopping parameter net inflow by overtopping per unit length of a breakwater overtopping per unit length of breakwater with no return flow runup SYMBOLS AND DEFINITIONS——Continued wave period mean net water velocity for flow through a gap = V/A, dimensionless velocity empirical overtopping parameter breakwater seaward-face slope angle surf similarity parameter Fy pasttid deve sn wl : re : i. 4 shen wc Diese tenia»: re ie a . oe QR, aet. Lot low he eimanepning | ofa eal ine , 7 + w soap ixtenl overtopping parnnst ex a = ast intice uy eer vogtitng tend Hott seat af 4 ae | en oor m iv : ty ieréontng, par wrod | oak of brava = he atiiiaty fm ei ‘ESTIMATION OF FLOW THROUGH OFFSHORE BREAKWATER GAPS GENERATED BY WAVE OVERTOPPING by William N. Seeltg and Todd L. Walton, Jr. I. INTRODUCTION Offshore breakwaters are often constructed to protect harbors or eroding coasts from wave action. Wave overtopping of segmented breakwaters generates a seaward flow through breakwater gaps. Low discharges and low water velocities are usually desirable in gaps between breakwaters. High velocities may be a hazard to navigation or swimmers, and large net exit flows through the gaps May transport sediment out of the breakwater area. This report illustrates a technique for predicting the net discharges and mean velocity through breakwater gaps caused by overtopping. II. HYDRAULICS OF DETACHED BREAKWATERS Since the cost of a breakwater increases with the height of the structure, it may be necessary to build the structure to allow some wave overtopping (Fig. 1). A moderate overtopping rate, which helps maintain water quality by encour- aging circulation, may also be desirable. If the breakwater is impermeable the volumetric rate of overtopping per unit length by breakwater, q, (assuming mo return flow over the breakwater), may be predicted (Weggel, 1976; U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1977) by (1) PROTECTED REGION Np = P= ponding level for an enclosed system SWL Figure 1. Definition sketch. where g = the acceleration due to gravity H5 = the equivalent unrefracted deepwater wave height R = the vertical: height of runup on the structure if the breakwater were high enough so that no overtopping occurred F = breakwater freeboard = h - d, h = the structure crest elevation ch ae the water depth at the toe of the structure. Qs and a are empirical overtopping coefficients found in the Shore Protection Manual (SPM) (U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1977, Ch. 7). Sample values of the empirical coefficients for an impermeable riprap structure with a 1 on 1.5 seaward slope are shown in Figure 2. A first approximation of the wave runup on rubble-mound breakwaters may be estimated using the equation of Ahrens and McCartney (1975): nS Re ge aca Lo where Ly is deepwater wavelength, and 6 is the slope angle of the seaward face of the breakwater; the empirical coefficients a = 0.692 and b = 0.504 are recommended. Note.--Other methods for estimating runup on various structures may be found in the SPM (U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1977) and Stoa (1979). Equations (1) and (2) were developed using monochromatic wave tests, so they should be used for swell wave conditions where the wave height and period from one wave to the next is approximately constant. The method of Ahrens (1977) for modifying equations (1) and (2) for irregular waves is recommended for irregular waves generated by nearby storms. The irregular wave overtopping prediction procedure is rather complicated, so the computer program BWFLOW2 (CERC program number 752X6R1ANC) is recommended for irregular waves. This pro- gram is available in the Corps of Engineers Computer Library at U.S. Army Waterways Experiment Station, Vicksburg, Mississippi. Note that the irregular wave overtopping method tends to be conservative because a Rayleigh wave height distribution is assumed, while the actual distribution may be truncated due to depth or steepness limited breaking. 1. Enclosed Breakwater Systems. If the breakwater system is enclosed on either end by impermeable groins and the breakwater has no gaps, water overtopping the breakwater would cause the water level landward of the breakwater, hp, to rise. Eventually, the zone landward of the breakwater would fill up to a ponding level where the sea- ward flow of water over the breakwater would equal inflow and the net flow, Shas would be zero. Diskin, Vajda, and Amir (1970) tested a number-of breakwaters 10 Bs Appr imate Breaking! Limi 1 ee (110 Nearshore slope), or ie x nei Feat | RE main pa ne - = 0.8 Non=Breaking}—|—|_|- Hi i ie eect att : S { Riprop roughly , ! Papal 3 ft. in diameter ah 0.08 sw. fe o [-2) 4 *& (ft/sec®) | 0048 @- ; + (0.1600) Figure 2. Overtopping parameters, a and Q&, riprapped 1:1.5 structure slope on a 1:10 nearshore slope (from U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1977). at various water depths, wave heights, and wave periods and found that the ponding level (Fig. 3) may be estimated from F = 0.6e -(-0.7 ‘ a) aie” (3) 0.1 for ae 2.05 where F is the breakwater freeboard defined as (h-d,). The maximum ponding level occurs at F/Hg = 0.7 because this is the point just before the seaward flow over the top of the breakwater occurs. Note that there is scatter in the data used to develop equation (3) with approximately 90 percent of all data points falling within 20 percent of the equation. A sensitivity analysis shows that this scatter is not important for this report, because flow rates are weakly influenced by the value of P. Note that the laboratory tests used to develop equation (2) show some ponding for high breakwaters not overtopped and submerged breakwaters. This ponding occurs because the breakwater reduces the wave height landward of the structure and the change in wave height causes wave setup (Longuet—Higgins, 1967). Overtopping tests by Diskin, Vajda, and Amir (1970) show that the net over- topping rate, q,, for breakwaters may be estimated from an = a (1 - 32) (4) P/Ho F/Ho Figure 3. Ponding levels for porous multilayered breakwaters (after Diskin, Vajda, and Amir, 1970). I2 2. Offshore Breakwaters with Gaps. Overtopping of breakwaters causes a buildup of water in the zone landward of the structure. If there are gaps between the breakwaters and the breakwaters are not connected to shore, the butldup of water landward of the breakwaters causes flow through the openings (Fig. 4). Ome method of estimating the exit flow through breakwater gaps or inlets is to use a combined continuity-—energy equation for discharge. Q = VAc = Cq 28h, A, (5) where Cg is a discharge coefficient, A, is cross-sectional flow area at the water level of interest, and V is the mean velocity of water flowing through the gaps. Many factors may influence the magnitude of Cy but, as a first estimate, Cq = 0.8 is recommended for gaps. The discharge coefficient for spaces between breakwaters and the pee Cge>, has a recommended value of Cg, = 1.0. Breakwater Ace = Cross- Sectional Area =f Gap b >— Gap Flow Q >—__:—SasV hp = Difference in Mean Water Overtopping Levels N=3 End Flow Shoreline Figure 4. An offshore breakwater system. Note that in this first approximation of breakwater gap flow that the waves. are assumed to approach approximately normal to the breakwaters and shoreline, so the longshore current can be neglected. Other effects such as diffraction, refraction, reflection, and wave-current interactions have not been considered. If incident wave conditions do not vary rapidly with time, a condition will be reached where water flowing into the zone protected by the breakwaters will equal the exit flow through breakwater gaps or inlets. The equation describing this condition is hy do (1 = ne) Ne = 2ehp (CqgBdg(N - 1) + 2CacAce) (6) where N is the number of breakwaters, Aca is the cross-sectional flow area between the breakwaters and shoreline at the end of the system, and B is the gap width between breakwaters (Fig. 4). Solving equation (6) and putting into dimensionless form, the dimensionless velocity, becomes a function of a single coefficient, K, where 2g P |cgBa,(N - 1) + 2c Ne N28 F [cabs - D+ 2achee] (7) qo LN Figure 5, which gives the relation between dimensionless velocity and K, shows that any combination of factors causing K to increase will produce a smaller dimensionless velocity. For example, keeping all other factors constant, if the gap spacing B is increased, K will increase and V will be reduced. K and the resulting velocity may be easily solved using equation (7) and Figure 5. The computer program BWFLOW2 can also be used to solve the velocity and flow through breakwater gaps due to overtopping. This program is recom - mended if a large number of calculations are needed. The program is also sug- gested any time irregular wave conditions are assumed, because irregular wave overtopping rates are a complex function of the overtopping rate given by equa- tion (1). The cost of running BWFLOW2 is a few cents per condition of interest. It is recommended that V be kept below 0.5 foot (0.15 meter) per second for extreme design conditions. Velocities much higher than this value could transport significant amounts of sediment out of the breakwater system and may cause scour around the breakwaters. Recall that V is an average velocity through the gap and that local velocities in breakwater vicinity may be con- siderably higher. See ee aaa SECS Se MESES eee Ee SPEC ee a a a EEC U LIE SE eo 2 EEUU OSS LLU PTET Pe a 0 pe — 0.1 0.2 0.4 0.60.8 | 4 6 810 20 40 6080 K Figure 5. Dimensionless velocity as a function of K. III. EXAMPLE PROBLEMS Example problems are presented to illustrate the steps required for manual or computer computation. The examples indicate the relative importance of the breakwater design variables on the magnitude of V. 2 kk kK kK KK K KOK & OK & & EXAMPLE PROBLEM 1 * *& & ¥& & RR KKK KK KEE GIVEN: Four rubble-mound offshore breakwaters have the design conditions illustrated in Figure 6. FIND: ve assuming a monochromatic wave height of 8.0 feet (2.44 meters) at the structure. SOLUTION: Manual computation is illustrated in this example. Ho = 7.8 ft T=7s Monochromatic Wave 3 V £=400ft ciate d,=l2 ft TID TD mr => EEE Het Ace= 1,000 ft@ ema B= 125 ft tan 8 = 0.667 Cqe =!.0 Figure 6. Design conditions for example problem 1. The first step in computations is to determine values for the dimensionless parameters: H! ) 7.8 = ———; = 0.0049 eT? 32.2(7)2 and d Sim eer Hot ee bobs From Figure 2, a and Q& are estimated as a = 0.053 and Q* = 0.019. surf parameter and resulting runup are determined using equation (2): = paORGG7alaD r= : = 3.74 5.12(72) and 0.692(8) (3.74) . R= = 7.17 feet (1 + 0.504[3.74]) The breakwater freeboard is F = h - dg = 13 - 12 = 1.0 foot. The overtopping rate, q,, given by equation (1) is 0.1085 ge (4 = 1.) 0.053 fe) HER DOUG) Gees) 7 old ail. 9.53 cubic feet per second per foot of breakwater crest. The From equation (3) the ponding level is a= 2s P = 7.8(0.6)e7 0"? * 1-0/7.8)2 = 3.36 feet From equation (7) z= V64.4 3.36 [0.8(125) 12(4 - 1) + 2(1.0) 1,000] - 9.53(400) 4 or K = 5.4 The corresponding dimensionless velocity is ee ee Ere - cay2e P = 0.18 for K = 5.4 from Figure 5 and V = 0.18(0.8) V64.6 3.36 = 2.11 feet per second. kK kK RK KK Kk kK kk & OK ® ® EXAMPLE PROBLEM 2 * *% * RK RRR RK KKK KKK GIVEN: The same breakwater system as in example 1. FIND: V_ for irregular wave conditions with a significant wave height, H, = 8.0 feet (2.44 meters). SOLUTION: The computer solution is illustrated in this example with the input shown in Table 1. Resulting computer output is given in Table 2. The predicted velocity is V =_1.33 feet (0.14 meter) per second. This velocity is lower than the V obtained for monochromatic waves in example 1 (2.11 feet per second), because irregular waves of a given significant wave height have less overtopping than monochromatic waves. Table 1. Computer program input for example problem 2. iva. GHCHHOCOHOHIND AHOHHHOOON OOLoIDOCHOHCHHOHHHH Boon0nnb8 OCDDKCHHOOHHHHODD0DDD0000 92245617868 91002 YW GH 19 20 21 2723 26 75 26 D 2875 $6 11 37 1) M4 46 37 35 4B 41 87 5 44 45 46 41 £2.49 90 51 5759 SE 55 SE ST SE S9EO G1 G7 694 ES ES 6/0869 N21 A) eo FVUVTATTTTT TAT DATTA ATTA TATA 19079709T TTT TTA ata Table 2. Computer program output for example problem 2. hee IRREGULAR WAVES #888 N LCFT) 8CFT) HOCET) MCFT) TCSEC) OSCFT) HSCET) TANT O8 aLPHa G@ 400000 125000 7.8 866 %0 1240 13560- e667 00190 .0536 Cp CDE ACECFT2) RUNUP(FT) G@O(CFS) PCFT) « WC(FPS) B 400 1000.00 7,17 5e91 2,048 7,12 1.33 Kk KK kK Kk KOK KX & & ® EXAMPLE PROBLEM 3 * & & XK RK K RK KKK KK GIVEN: Three rubble-mound offshore breakwaters are located with d, = 12 feet (3.7 meters), 2 = 250 feet (76.2 meters), tan 9 = 0.667, and Ace = 1,440 square feet (134 square meters). FIND: The influence of breakwater freeboard, incident wave height, wave period, gap spacing, and shore attachment on V. SOLUTION: The computer program was used to make these calculations and results are given in Figures 7 to 10. Figure 7 shows that an increase in breakwater freeboard or gap to length ratio causes V to decrease. An increase in in- cident wave height and in wave period produces an increase in V as expected (Figs. 8 and 9). Shore attachment with impermeable walls forces more flow through breakwater gaps than for a detached system (Fig. 10). The most dra- matic effect of shore attachment occurs for relatively small breakwater gaps. kk ek AR ORK ROK KOR Rk OR RN Kk Oe KCRG CRA) KOR Re WOR * ke IV. SUMMARY AND CONCLUSIONS A method is presented for estimating the first approximation of the water velocity and flow rate through breakwater gaps caused by wave overtopping. Calculations can be performed either by hand, using a dimensionless curve, or by a computer program, BWFLOW2, available in the Corps of Engineers Computer Library. Examples of both calculation methods are given to illustrate the relative influence of various design parameters on the magnitude of the gap velocity, V. It is suggested that V not exceed 0.5 foot per second. High values of V may produce scour around structures and transport sediment out of the zone protected by the breakwaters. *A uo 3ufoeds des pue 7YyZTey SAePM ZUSPTOUT FO JO9TTY v/a O'| °9 oinsTty ne) "A uo Suroeds des pue pieoqesry JaIeMyYeorq FO Wd9TTq gi Opp l= v JajDMyDa1g adois G1 /| 40S2¢ = Y 21 = P (S@AomM J0)NBass!) Sen Miya °f 9ain3Ttq (S/44) A 19 ‘A uo B3upfoeds des pue queuyoezje er10ys JO 3O9FTTT y/9 Or c‘| 0'| GO 0) Qul}as0yS ye "OT eansta euljasoys (S/43) A (SaaDm 40j)nbas!) *A uO sutoeds de3 pue pofied saeM JO 09zF5q y/a 0°} GO ) °6 21n3Tq €=N (S@ADM 91;DWOIYIOUOW ) (S/43) A 20 LITERATURE CITED AHRENS, J.P., "Prediction of Irregular Wave Overtopping," CETA 77-7, U.S. Army, Corps of Engineers, Coastal Engineering Research Center, Fort Belvoir, Va., Dec. 1977. AHRENS, J.P., and McCARTNEY, B.L., "Wave Period Effect on the Stability of. Riprap," Proceedings of Civil Engtneertng in the Oceans/III, American Society of Civil Engineers, 1975, pp. 1019-1034 (also Reprint 76-2, U.S. Army, Corps of Engineers, Coastal Engineering Research Center, Fort Belvoir, Va., NTIS A029 726). DISKIN, M., VAJDA, M., and AMIR, I., "Piling-Up Behind Low and Submerged Permeable Breakwaters," Journal of Waterways and Harbors Divtston, No. WW 2, May 1970, pp. 359-372. LONGUET-HIGGINS, M.S., "On the Wave-Induced Difference in Mean Sea Level Between the Two Sides of a Submerged Breakwater," Journal of Marine Research, Vol. 25, No. 2, 1967, pp. 148-153. U.S. ARMY, CORPS OF ENGINEERS, COASTAL ENGINEERING RESEARCH CENTER, Shore Proteetton Manual, 3d ed., Vols. I, II, and III, Stock No. 008-022-00113-1, U.S. Government Printing Office, Washington, D.C., 1977, 1,262 pp. WEGGEL, J.R., "Wave Overtopping Equation," Proceedings of the 15th Coastal Engineering Conference, American Society of Civil Engineers, 1976, pp. 2737-2755 (also Reprint 77-7, U.S. Army, Corps of Engineers, Coastal Engineering Research Center, Fort Belvoir, Va., NTIS AO42 678). 2| Le9 8-08 “ou BqTssn* €0720L °9-08 ‘ou pre TeOTUYDe, “1eqUeD YOTeEeSey BuTAs0UTSUY TeIsSeOD °*S°N :soTzeg “TIT *T ppol ‘uojTeM “IT °OTITL “TL *SOhEM °C *potaed DAPM °H e8utddoq19A0 9AeM °F *qy3tTey oAeM °Z *siloqemyeorg °| *petytoeds aq ued seAeM TeTNSe1AIT JO oTJeMOTYS -ouol zJoyITe Wey oS pedoTeAep sem poyqoW syy “*SieqeMyeeIq oy Jo Sutddojzea0 aaem Aq pesned siojzeMyeeIq pajyueMses e1oyszjo Jo sded 943 y8noiyj MOTF Jou oyR BuTJeWTIse I10F poyjzeM e squesead jaode1 sTUL *soouelesol TeoTydeiZ0TTGTq sepnTouy (8-08 °ou { deqUeD YOIReSeYy BuTAV.UTSUq qeaseop °s* -- pre jyeoTuysel) -- ‘md /Z + “ITF : “d [TZ] °0861 ‘e0TAIeS UOTJEWIOFUT TeOTUYDET TeUCTIEN WorZ oTqeTTeAe : ‘eA ‘pTetTssutads $ geaque) yoreesoy BuTAsquTSuq TeqIseoD °*S*n : “eA SATOATSG 3104 —- °3If ‘uOozTeM °T ppoy pue B3ITees °N werTTIM Aq / 3utddoj,1eA0 |AeM fq peqeisues sde3 azeqemyeer1q er0ysTyJO yYysnoi1yi MOTF JO uOoTIeUTISY °N WETTTIM ‘3TT28eS Lc9 8-08 *ou BITSSN* €0¢OL °9-08 °oU pre [eOTUYDeT *1eqUeD YOTeesey BuTIeeuTsUq TeISseOD °*S°f sseTzes *TIT *T ppoL ‘uojTeM “IT °OTITL “IT *“SOAeM °C *potaied DARPM °H *Zutddoj19A0 BsARM °C *qy3ToOU sAeM °Z *sIoJEMmyeoIg °T *petztoeds aq ued seAeM IeTNSeIIT 10 OTZeEMOAYD -ouow zeyITe Wey Os pedoTeAesp sem poyjew syuy “*SieqemMyYeeIq 9y} JO Sutddoz1eA0 aaem Kkq pasned siojeMyeeIq pequemses e1o0ysTyo jo sde3 ayy ysnoryi moTy Jou oy BuTJeMTAse AOF poyjem e squesead yiode1 sTyy *saouetesel [TeoTydersoTTqTq sepnTouy (8-08 °ou £ JoqUeD YDIeesey BuTIeeuTsUy qeaseon *s*n -- pre jeotuysey) -- wo /Z +: “TTF : ed [TZ] “0861 “20TAIeS UOTIeUIOFUT TeOTUYDe, TeUOCTIeN WorZ sTqeTTeae : “eA ‘pTeTssutads § geque) yoreesoy BuTAoouTSuq TeIseoD “Sen : “°eA SATOATOY 3104 == *if ‘u0qTeM *T ppoy pue B3TTees *N weTTTTM Aq / Butddoj1en0 sAeM hq poejereues sde8 azaqemyeoiIq ei10yszyo Yysnor1yI MOTZ JO UOT eUTISY °N WETTTIM “3TTeeg Le9 8-08 *ou eBaTSsn* €0cOL °9-08 °OU pTe TeoOTUYDe, *1oqUe) YoTeesey SuTIeeuTsuq TeISeOD °S°n *SseTtes “TIT *T ppoL ‘uoqTeM *IT °OTITL “I *SsoAeM °C *potied SAREM °h eS8utddoj19A0 SARM °¢ *3y3TOYy AEM °Z% *siloqemyeelg °T *potytoeds oq ued SeAPM ABTNSe1IT IO dTJeWOoIYS -ouou zayITe ey, os pedoTeAsp sem poyjem sy, *SieqzeMyYPeIq YR JO SutddojzeA0 aaem Aq pesned siojemyYPeIq peqUeMes eioysyTjo jo sdes 3y ysno1ry} MOTZ JOU oy. 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