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WHO 

DOCUMENT 

COLLECTION 



CcA^^ En^' t^^^ -c-tr . 
MR 77-7 V. 5- 



Laboratory Effects in Beach Studies 

Volume Itt 
Movable-Bed Experiments with Ho/Lo = 0.021 (1971) 

by 

Charles B. Chesnutt and Robert P. Stafford 

MISCELLANEOUS REPORT NO. 77-7 
NOVEMBER 1977 




Approved for public release; 
distribution unlimited. 



U.S. ARMY, CORPS OF ENGINEERS 

COASTAL ENGINEERINe 
RESEARCH CENTER 



Kingman Building 
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 22151 

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. 



DOCUMENT 

COtLECTiON 



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SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) 



REPORT DOCUMENTATION PAGE 



READ INSTRUCTIONS 
BEFORE COMPLETING FORM 



1. REPORT NUMBER 

MR 77-7 



2. GOVT ACCESSION NO. 



3. RECIPIENT'S CATALOG NUMBER 



«. TITLE (end Subtitle) 

LABORATORY EFFECTS IN BEACH STUDIES 
Volume III. Movable-Bed Experiments With 
U^/Lo = 0.021 (1971) 



5. TYPE OF REPORT a PERIOD COVERED 

Miscellaneous Report 



6. PERFORMING ORG. REPORT NUMBER 



7. AUTHORfo; 

Charles B. Chesnutt 
Robert P. Stafford 



8. CONTRACT OR GRANT NUMBERfsJ 



9. PERFORMING ORGANIZATION NAME AND ADDRESS 



Department of the Army 

Coastal Engineering Research Center (CERRE-CP) 

Kingman Building, Fort Belvoir, Virginia 22060 



031192 



11. CONTROLLING OFFICE NAME AND ADDRESS 

Department of the Army 

Coastal Engineering Research Center 

Kingman Building, Fort Belvoir, Virginia 22060 



12. REPORT DATE 

November 1977 



13. NUMBER OF PAGES 

111' > \o f 



14. MONITORING AGENCY NAME 8 ADDRESSfy/ d///eren( from Controlling Office) 



IS. SECURITY CLASS, (of this report) 



UNCLASSIFIED 



16. DISTRIBUTION STATEMENT (of thia 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 revere 

'~^ Breakers 

Coastal engineering 

Currents 

Model studies 



Je If necessary and Identify by block number) 

Movable-bed experiments Wave height variability 
Wave envelopes ^, ' Wave reflection 
Wave generators ,■.■ , •<P'Wave tanks 



20. ABSTRACT CCanitmje aa r*veram attfi* ff n*c»>TO«ry and Identify by block number) 

Two movable-bed experiments were conducted in 6- and 10-foot-wide wave tanks 
for 375 and 335 hours, respectively, with a wave period of 1.90 seconds and 
a generated wave height of 0.36 foot. 

Significant lateral variations occurred in the profile development rate and 
profile shape in the 10-foot tank, which did not occur in the 6-foot tank, 
indicating that tank width can affect the study of littoral processes in 



movable-bed experiments. 



(Continued) 



on ""^ 



EOrTlON OF t NOV 6S IS OBSOLETE 



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SECURITY CLASSIFICATtOPf OF THIS PAGE (When Data Entered) 



UNCLASSIFIED 



SECURITY CLASSIFICATION OF THIS PAGEfWin 



Wave reflection from the movable-bed profile varied considerably as the 
profile in both wave tanks developed from an initial planar (0.10) slope 
to one closer to equilibrium. The reflection coefficient, Kn, varied from 
0.08 to 0.30 in the 6-foot tank and from 0.03 to 0.16 in the 10-foot tank. 
The variations in K^ can be related qualitatively to profile development. 

Even with the fine-grained, well-sorted sediment used, a measurable 
sorting occurred as the finer material was eroded and deposited offshore. 



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PREFACE 

Ten experiments were conducted at the Coastal Engineering Research 
Center (CERC) from 1970 to 1972 as part of an investigation of the Lab- 
oratory Effects in Beach Studies (LEBS), to relate wave height varia- 
bility to wave reflection from a movable-bed profile in a wave tank. The 
investigation also identified the effects of other laboratory constraints. 
The LEBS project is directed toward the solution of problems facing the 
laboratory researcher or engineer in charge of a model study; ultimately, 
the results will be of use to field engineers in the analysis of model 
studies. The work was carried out under the CERC coastal processes 
program. 

This report (Vol. Ill) is the third in a series of eight volumes on 
the LEBS experiments. Volume I describes the procedures used in the 
10 LEBS experiments, and also serves as a guide for conducting realistic 
coastal engineering laboratory studies; Volumes II to VII are data reports 
covering all experiments; Volume VIII summarizes the LEBS experiments 
detailed in the earlier volumes. 

This volume analyzes two movable-bed experiments run under nearly the 
same conditions as the experiments described in Volume II. As in Volume 
II, these repeat experiments show a slower approach to equilibrium profile 
than normally anticipated in movable-bed experiments, and a probable re- 
lation between tank width and profile development. These experiments 
indicate an even greater effect of profile change on reflection coeffi- 
cient, and thus on wave height variability. However, the effect of 
temperature on the profile development indicated in Volume II is not 
supported by these experiments. 

This report was prepared by Charles B. Chesnutt, principal investigator, 
and Robert P. Stafford, senior technician in charge of the two experiments. 
Dr. C.H. Everts, now Chief, Geotechnical Engineering Branch, supervised 
3 months of the testing reported in this volume. Dr. C.J. Calvin, Chief, 
Coastal Processes Branch, provided general supervision. 

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. 




/JOHN H. COUSINS 
Colonel, Corps of Engineers 
Commander and Director 



CONTENTS 

Page 

CONVERSION FACTORS, U.S. CUSTOMARY TO METRIC (SI) 8 

I INTRODUCTION 9 

1. Background 9 

2. Experimental Procedures 10 

3. Subexperiment with H^/L^ = 0.002 11 

4. Scope 11 

II RESULTS 15 

1. Wave Height Variability 15 

2. Profile Surveys 29 

3. Sediment -Size Distribution 64 

4. Breaker Characteristics 79 

5. Water Temperature 82 

III PROFILE DEVELOPMENT AND REFLECTIVITY 82 

1, Profile Development 82 

2. Profile Reflectivity 92 

IV DISCUSSION OF RESULTS 97 

1. Wave Height Variability 97 

2. Profile Equilibrium 98 

3. Other Laboratory Effects 98 

V CONCLUSIONS AND RECOMMENDATIONS 99 

1. Conclusions 99 

2. Recommendations 100 

3. Further Analysis 100 

LITERATURE CITED 101 

APPENDIX EXPERIMENTAL PROCEDURES FOR 71Y-06 AND 71Y-10 103 

TABLES 

1 Summary of experimental conditions 10 

2 Experimental schedule for experiments 71Y-06 and 71Y-10 12 

3 Data collection schedule within runs for experiments 71Y-06 

and 71Y-10 14 

4 Wave heights during first 10 minutes for experiments 71Y-06 

and 71Y-10 16 

5 Incident wave heights in fixed-bed tanks 17 

6 Incident wave heights in movable-bed tanks 19 

7 Wave heights during first 10 minutes of long waves near 

end of experiment 71Y-06 22 



CONTENTS 

TABLES-Continued 

Page 

8 Reflection coefficient by manual method for experiments 71Y-06 

and 71Y-10 23 

9 Slope of beach face at the SWL intercept in experiments 71Y-06 

and 71Y-10 44 

10 Sediment-size analysis at various hours for experiment 71Y-06. . . 71 

11 Sediment-size analysis at various hours for experiment 71Y-10. , . 75 

12 Summary of median grain-size values within profile zones for 

experiments 71Y-06 and 71Y-10 78 

13 Summary of profile development for experiment 71Y-06 87 

14 Summary of profile development for experiment 71Y-10 90 

FIGURES 

1 Reflection variability in fixed-bed tanks 26 

2 Reflection variability in movable-bed tank of experiment 

71Y-06 27 

3 Reflection variability in movable-bed tank of experiment 

71Y-10 '. 28 

4 Interpretation of contour movement plots 30 

5 Definition of coordinate system 32 

6 Definition sketch of profile zones (experiment 71Y-06) 33 

7 Profile changes along range 1, experiment 71Y-06 34 

8 Profile changes along range 3, experiment 71Y-06 35 

9 Profile changes along range 5, experiment 71Y-06 36 

10 Profile changes along range 1, experiment 71Y-10 37 

11 Profile changes along range 3, experiment 71Y-10 38 

12 Profile changes along range 5, experiment 71Y-10 39 

13 Profile changes along range 1 , experiment 71Y-10 40 

14 Profile changes along range 9, experiment 71Y-10 41 



5 



CONTENTS 

FIGURES-Continued 

Page 

15 Comparison of initial contour movement on the foreshore zone 

in experiment 71Y-06 42 

16 Comparison of initial contour movement on the foreshore zone 

in experiment 71Y-10 43 

17 Shape of foreshore zone near end of experiment 71Y-10 48 

18 Comparison of the shoreline (0 contour) movement in experiments 

71Y-06 and 71Y-10 49 

19 Changes in the inshore zone along range 1, experiment 71Y-06 ... 50 

20 Changes in the inshore zone along range 3, experiment 71Y-06 ... 51 

21 Changes in the inshore zone along range 5, experiment 71Y-06 ... 52 



22 Comparison of the -0.3-, -0.4-, -0.6-, -0.7-, and -0.8-foot 
contour movements in experiment 71Y-06 



23 Movement of bars and troughs along range 3 in experiment 71Y-06 

24 Changes in the inshore zpne along range 1, experiment 71Y-10 

25 Changes in the inshore zone along range 3, experiment 71Y-10 

26 Changes in the inshore zone along range 5, experiment 71Y-10 

27 Changes in the inshore zone along range 7, experiment 71Y-10 

28 Changes in the inshore zone along range 9, experiment 71Y-10 



53 
55 
56 
57 
58 
59 
60 



29 Comparison of the -0.3-, -0.4-, -0.6-, -0,7-, and 0.8-foot 

contour movements in experiment 71Y-10 61 

30 Comparison of the -0.9-, -1.2-, and -2.1-foot contour 

movements in experiment 71Y-06 63 

31 Comparison of the -0.9-, -1.2-, and -2.1-foot contour 

movements in experiment 71Y-10. . 65 

32 Comparison of profiles along range 3 at 375 and 380 hours in 

experiment 71Y-06 66 

33 Profile changes along range 1 in experiment 71Y-06 between 

375 and 380 hours 67 



CONTENTS 

FIGURES-Continued 

Page 

34 Profile changes along range 3 in experiment 71Y-06 between 

375 and 380 hours 68 

35 Profile changes along range 5 in experiment 71Y-06 between 

375 and 380 hours 69 

36 Long wave deposition on foreshore between 375 and 380 hours in 

experiment 71Y-06 70 

37 Movement of breaker position in experiment 71Y-06 80 

38 Movement of breaker position in experiment 71Y-10 81 

39 View of breakers from backshore at 330 hours in experiment 

71Y-10 83 

40 Contour maps of experiment 71Y-10 at 135 and 

335 hours 84 

41 Seaward directed ripples on the inshore along range 1 in 

experiment 71Y-10 85 

42 Water temperature data from experiments 71Y-06 and 71Y-10 86 

43 Comparison of water temperature and shoreline position in 

experiments 71Y-06 and 71Y-10 89 

44 Erosion and accretion in 6- and 10-foot tanks 93 

45 Comparison of the -0.7-foot contour position and K,-, in 

experiments 71Y-06 and 71Y-10 95 

46 Correlation of the -0.7-foot contour position and % in 

experiment 71Y-06 96 



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 in dies 


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 


1.8532 


kilometers per hour 


acres 


0.4047 


hectares 


foot-pounds 


1.3558 


newton meters 


millibars 


1.0197 X 10" 


^ kilograms per square centimeter 


ounces 


28.35 


grams 


poiiiids 


453.6 


grams 




0.4536 


kilograms 


ton, long 


1.0160 


metric tons 


ton, short 


0,9072 


metric tons 


degrees (angle) 


0.1745 


radians 


Fahrenheit degrees 


5/9 


Celsius degrees or Kelvins^ 



^To obtain Celsius (C) tem])erature 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. 



LABORATORY EFFECTS IN BEACH STUDIES 
VolLime III. Movable-Bed Experiments With H^/L^ = 0.021 (1971) 

by 

Charles B. Chesnutt and Robert P. Stafford 

I. INTRODUCTION 
1. Background . 

Profiles in movable-bed, coastal engineering laboratory experiments 
and models with constant wave and sediment conditions are expected to 
reach an equilibrium shape after a sufficiently long time. Laboratory 
studies of longshore transport often depend on having an equilibrium 
profile to accurately determine the longshore transport rate (Savage, 
1959, 1962; Fairchild, 1970a) . Coastal engineering models are frequently 
based on simulating an equilibrium profile, which implies a profile whose 
mean position is fixed in space for the given wave and sediment condi- 
tions, with the expectation that the actual profile at any given time 
will deviate from the mean profile. However, equilibrium profiles are 
not always easily attained (Savage, 1962; Fairchild, 1970a) . 

The Laboratory Effects in Beach Studies (LEBS) project was initiated 
at the Coastal Engineering Research Center (CERC) in 1966 to investigate 
the causes of wave height variability and other problems associated with 
movable-bed coastal engineering laboratory studies. Ten movable-bed 
laboratory experiments were conducted from 1970 to 1972 in the CERC 
Shore Processes Test Basin (SPTB) to measure the variations in reflec- 
tion as the profile developed toward equilibrium. The 10 experiments 
are described in an 8-volume series of reports; this study is Voliime III 
of the series. An extended discussion of the contents and purposes of 
this series is available in Volume I (Stafford and Chesnutt, 1977). 

The first two experiments discussed in Volume II (Chesnutt and 
Stafford, 1977) led directly to the two experiments described in this 
report. These two experiments were conducted primarily to relate the 
variation in wave height to changes in the movable-bed profile. The 
experiments were to continue until the profile reached equilibrium, at 
which point it was assumed that the wave height variability would be 
significantly reduced. 

However, the beach had eroded to the back of the tank before the 
profile had reached equilibrium, and the two experiments were continued 
by periodically adding sand to the backshore. Even with the periodic 
nourishment, the profile never reached equilibrium and the wave heights 
remained variable. 



The two experiments discussed in this study were repeats of the first 
two experiments with more sand added so that the initial test length 
(distance from the wave generator to the initial Stillwater level (SWL) 
intercept) was shortened by 7 feet (2.1 meters) in both tanks, in hopes 
that the erosion would not reach the back of the tank before the profile 
attained equilibriiom. 

The two experiments covered in this study have been discussed in part 
in earlier reports. Chesnutt, et al. (1972) discussed the development of 
the profiles in four LEBS experiments, including the two in this study. 
Chesnutt and Galvin (1974) analyzed the relationship between reflection 
variability and profile development in the same four experiments discussed 
by Chesnutt, et al . (1972). Chesnutt (1975) analyzed other laboratory 
effects observed in three LEBS experiments, including one of the two in 
this volume. 
2. Experimental Procedures . 

The experimental procedures used in the LEBS experiments are described 
in Volume I (Stafford and Chesnutt, 1977) which provides the necessary 
details on the equipment, quality control, data collection, and data 
reduction for all 10 experiments. 

The data collection and reduction procedures unique to the two experi- 
ments in this study are documented in the Appendix. The conditions of 
these two LEBS experiments (71Y-06 and 71Y-10) are summarized in Table 1. 
The table shows that the initial slope, water depth, wave period, wave 
fieight, and sand size were the same in both experiments. 



Table 1 


Summary of 


experimental cond 


itions. 


Experiment^ 


Initial test 

length 

(ft) 


Initial 
slope 


Wave 

period 

(s) 


Generated 

wave height 

(ft) 


71Y-06 
71Y-10 


93.0 

54.7 


0.10 
0.10 


1.90 
1.90 

— ;= — TTS s =: 


0.36 
0.36 



^Refer to Volume I (Stafford and Chesnutt, 1977) for 
relation between these experiments and the other eight 
LEBS experiments. 

NOTE. --The same sediment was used in both experiments; 
the initial d^Q (by dry sieve analysis) was 0.23 milli- 
meter. 

Two experimental facilities were used (see Figs. 3 and 4 in Vol. I 
and Fig. A-1 in the App.). Each facility consisted of two side-by-side 
wave tanks, one with a 0.10 concrete slope and the other a sand slope. 
A generator was common to each pair of tanks so that each had identical 
wave energy input. The operation of the generators is described in 
Section IV and Appendix B of Volume I. The concrete slope provided a 
control (a bench-mark value) for the varying reflection measured in the 
neighboring tank with the movable bed. 



10 



The basic difference between the two facilities was the tank width. 
One pair of tanks, each 6 feet (1.8 meters) wide, was used for experi- 
ment 71Y-06; the other pair, each 10 feet (3.0 meters) wide, was used 
for experiment 71Y-10. The initial test length on the sand side was 93 
feet (28.3 meters) in experiment 71Y-06 and 54.7 feet (16.7 meters) in 
experiment 71Y-10 (Table 1). The initial test length was 7 feet greater 
on the concrete side in both tanks. 

The initial grading of the sand slope in experiment 71Y-06 v.'as on 3 
May 1971. The first run was on 11 May 1971, the last run was on 8 Decem- 
ber 1971 after 380 hours, and the data collection was completed 13 Decem- 
ber 1971. Experiment 71Y-10 began 18 June 1971, stopped on 30 November 
1971 after 335 hours, and data collection completed 16 December 1971. 
The dates are important because the experiments were run in outdoor 
facilities with water temperature varying with ambient air temperature. 
The major events of each experiment and the cumulative time at the end 
of each run are summarized in Table 2„ 

Table 3 gives the data collection schedule within each run for 1- , 
2-, and 5-hour runs. During the first 2 hours when the runs were less 
than 1 hour long, the same data were collected, with the schedule 
depending on the length of the run„ 

3. Subexperiment with H^/L^ = 0.002 . 

After 375 hours in experiment 71Y-06, the beach had eroded to the end 
of the tank. The experiment was continued for an additional 5 hours with 
a much longer, lower wave, which resulted in accretion on the foreshore. 
The experimental conditions unique to this subexperiment are given in the 
Appendix. 

4. Scope . 

This report describes and analyzes the reduced data from LEBS experi- 
ments 71Y-06 and 71Y-10. The original data are available in an unpub- 
lished laboratory memorandum (No. 2) (Chesnutt and Leffler, 1977) filed 
in the CERC library (CERTI-LI) . 

Wave reflection, profile evolution, sediment-size distribution, 
breaker characteristics, and water temperature data are discussed in 
Section II. Section III discusses (a) profile development, including 
the interrelation of changes in profile shape, sediment-size distribu- 
tion, breaker characteristics, and water temperature; and (b) profile 
reflectivity, including the interrelation of changes in profile shape, 
breaker characteristics, and wave reflection. Section IV discusses the 
results of wave height variability, profile equilibrium, and other 
laboratory effects. 

The conclusions and recommendations (Sec. V) are directed toward the 
identification and solution of problems facing the laboratory researcher 

II 



TaUe 2. Schedule for experiments 71Y-06 and 71Y-10. 



Cumulative time 


Date 


Wave record No. 


Su.-vey No. 


Special data 


(hr:min) 


(1971) 






collected 


Experiment 71Y-06 


0:00 






1 


sand samples 


0:10 


12 May 


001 


2 




0:25 




002 


3 




0:40 




003 


4 




1:00 




004 


5 




1:30 




005 


6 




2:00 




006 


7 




3:00 

2 




007 
2 


« 2 




9:00 




013 


14 




10:00 


28 May 


014 


15 




12:00 
3 




015 

2 


16 

2 




26:00 


9 June 


022 


23 


ripple photos, 


3 




2 


2 


sand samples 


52:00 


14 July 


035 


36, 36S 


profile survey, 
ripple photos. 


3 




2 


2 


sand samples 


98:00 




058 


59 




100:00 


5 Aug. 


059 


60,61 


profile survey, 
ripple photos, 
sand samples 


105:00 




060 


62 




4 




2 


2 




200:00 


10 Sept. 


079 


81,82 


profUe survey, 
ripple photos. 


4 




2 


2 


sand samples 


300:00 


14 Oct. 


099 


102, 103 


profile survey, 
ripple photos, 
sand samples 


4 




2 






370:00 




113 


117 




375:00 


11 Nov. 


114 


118,119 


profile survey, 
ripple photos, 
sand samples 


375:10 




115 


120 




375:40 




116 


121 




376:30 




117 


122 




378:00 




118 


123 




380:00 


8 Dec. 




124, 125 


profile survey, 
ripple photos, 
sand samples 



'Wave records were taken during run ending at cumulative time shown; surveys, sand samples, and ripple 
photos were taken after tlie run ending at the cumulative time shown (see also Table 3). 
Increments of 1. 
Increments of 2. 
Increments of 5. 



12 



Table 2. Schedule for experiments 71Y-06 and 71Y-10.— Continued 



Cumulative time 
(hr:min) 


Date 
(1971) 


Wave record No. 


Survey No. 


Special data 
collected 


Experiment 71Y-10 ] 


0:00 






1 




0:10 
0:25 
0:40 
1:00 
1:30 
2:00 

3:00 

2 

9:00 


18 June 


001 
002 
003 
004 
005 
006 

007 

2 

013 


2 

3 

4 

5 

6 

7 

8 
2 

14 




10:00 

12:00 
3 


9 July 


014 
015 

2 


15 
16 

2 




24:00 
3 


16 July 


021 
2 


22,23 

2 


profile survey, 
ripple photos, 
sand samples 


50:00 

3 

98:00 


2 Aug. 


034 

2 
058 


36,37 

2 

61 


profile survey, 
ripple photos, 
sand samples 


100:00 

105:00 

4 


30 Aug. 


059 

060 
2 


62,63 
64 

2 


profile survey, 
ripple photos, 
sand samples 


200:00 

4 


4 Oct. 


079 
2 


83,84 

2 


profile survey, 
ripple photos, 
sand samples 


300:00 

4 


9 Nov. 


099 

2 


104, 105 

2 


profile survey, 
ripple photos, 
sand samples 


335:00 


30 Nov. 


106 


112,113 


profile survey, 
ripple photos, 
sand samples 



Wave records were 
photos were taken afte 
Increments of 1. 
Increments of 2. 
Increments of 5. 



taken during run ending at cumulative time shown; surveys, sand samples, and ripple 
r the run ending at the cumulative time shown (see also Table 3). 



13 



Table 3. Data collection schedule within runs for experiment 


s 71Y-06 and 71Y-10. 


Event 


Time within runs (hrrmin)' 




1-hr runs 


2-hr runs 


5-hr runs 


Photo at foreshore before start 


before start 


before start 


before start 


Photos of breaker and runup 


0:01 


0:01 


0:01 


Photos of breaker and runup before wave envelope 


0:19 


0:59 


3:59 


Recording of wave envelope started 


0:20 


1:00 


4:00 


Preparation of visual observation form 




1:50 


4:50 


Photos of breaker and runup; entry of breaker and 
runup stations in logbook 


0:59 


1:59 


4:59 


Photo of foreshore after water surface had calmed 


after stop 


after stop 


after stop 


Profile survey 


after stop 


after stop 


after stop 


Water temperature data collected in morning and 
afternoon of eacli day of testing; however, there 
may have been more than one run during each day. 









See Table 2 for distributdon of 1-, 2-, and 5-hour runs. 



or engineer in charge o£ a model study. Field engineers should also be 
aware o£ these results when analyzing model studies for coastal engineer- 
ing projects. 

The data in this study (particularly the profiles) may have other 
uses. The researcher can use these data, after consideration of the 
laboratory effects, to analyze short- and long-term changes in profile 
shape. After an analysis of the scale and laboratory effects, the field 
engineer may use these data to determine generalized shoreline recession 
rates. 

II, RESULTS 

1. Wave Height Variability . 

a. Incident Wave Heights . 

(1) 1.90-Second Wave . Wave height measurements from the con- 
tinuous recording of water surface elevation along the center range at 
station +25 during the first 10 minutes of each experiment are shown in 
Table 4. The wave heights in the movable-bed tanks varied from 0.26 to 
0.52 foot (7.9 to 15.8 centimeters) in experiment 71Y-10, and from 0.20 
to 0.41 foot (6.1 to 12.5 centimeters) in experiment 71Y-06. Ignoring 
the first group of waves, the range of wave heights within the first 10 
minutes was 0.11 foot (3.4 centimeters) in experiment 71Y-10 and 0.10 
foot (3.0 centimeters) in experiment 71Y-06„ In the fixed-bed tanks, 
again ignoring the first group, the range of wave height variation was 
0.12 foot (3.7 centimeters) in experiment 71Y-10 and 0.07 foot (2.1 
centimeters) in experiment 71Y-06, The range of wave height variation 
was as great in the fixed-bed tanks as in the movable-bed tanks. 

The average wave height in the movable-bed tank for each record was 
determined by averaging the average of the last 10 waves in the last 
20-second interval for each of the 10 minutes. In experiment 71Y-10, 
the average wave height was 0.33 foot (10,1 centimeters) in experi- 
ment 71Y-06, the average wave height was 0.36 foot (11.0 centimeters). 
Because the waves were recorded at the same distance from the profile, 
the difference in the average wave height is likely due to the difference 
in the initial test length which affects the development of secondary 
waves or re-reflection from the wave generator. During the first 10 
minutes, there was little difference in the average wave height between 
the movable- and fixed-bed tanks for either experiment, even though the 
gages in the fixed-bed tanks were 7 feet farther from the profile. 

The average incident wave heights in the fixed-bed tanks from the 
two experiments are shown in Table 5. These heights were determined as 
part of the manual method for determining the reflection coefficient, K^ 
(see Vol. I). This variation is probably caused by generator operation 
variation, measurement errors, and all errors not caused by a changing 
profile in both movable- and fixed-bed tanks. The range of variation 
was 0.03 foot (0.9 centimeter) in experiment 71Y-10 and 0.04 foot (1.2 
centimeters) in experiment 71Y-06. 



15 









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16 



Table 5. Incident wave heights in 


[ixed-bed tanks. 


Time (hr) 


Incident wave heiglit (ft)' 


Experiment 71Y-06 


Experiment 71Y-10 


1.5 


0.38 


0.35 


6.0 


0.39 


2 


7.0 




0.35 


12.0 


0.38 


0.36 


22.0 


0.36 





24.0 




0.34 


32.0 


0.38 


0.37 


42.0 


0.37 




44.0 




0.35 


52.0 


0.38 


0.35 


62.0 


0.39 


0.36 


72.0 


0.39 


0.37 


82.0 


0.37 


0.36 


92.0 


0.38 


0.35 


105.0 


0.40 


0.35 


130.0 


0.39 


0.35 


155.0 


0.40 


0.37 


180.0 


0.39 


0.37 


205.0 


0.40 


0.37 


230.0 


0.39 




235.0 




0.37 


250.0 




0.34 


255.0 


0.38 





280.0 


0.38 


0.36 


305.0 


0.39 


0.37 


324.0 


0.39 




330.0 


0.38 


0.36 


334.0 


0.38 





339.0 


0.38 





344.0 


0.38 





349.0 


0.38 





354.0 


0.38 




359.0 


0.37 




364.0 


0.38 





369.0 


0.38 





374.0 


0.37 





Avg. 


0.38 


0.36 



Each value is an average of wave heights at the nodes and 
antinodes of the wave envelope for run ending at indicated time. 
^Data for these times were not reduced. 



17 



The average incident wave heights in the movable-bed tanks from the 
two experiments are shown in Table 6. These heights were determined as 
part o£ the automated method for determining K^ (see Vol. I). The 
range of wave heights was 0.09 foot (2.7 centimeters) in both experiments. 
The difference in range of variation between fixed- and movable-bed tanks 
is due to the changing shape and position of the profile, causing a vary- 
ing re- reflection from the wave generator. The re-reflected wave super- 
posing with the generated wave created an incident wave which varied in 
time. Thus, the variation due to re-reflection was 0.06 foot (1.8 centi- 
meters) in experiment 71Y-10 and 0.05 foot (1.5 centimeters) in experi- 
ment 71Y-06. 

(2) 5.75-Second Wave . Table 7 shows the wave height measure- 
ments from the continuous recording of water surface elevation during 
the first 10 minutes of waves with the 3.75-second wave period. A well- 
developed profile was created by 375 hours of 1.90-second waves. Wave 
heights varied from 0.09 to 0.15 foot (2.7 to 4.6 centimeters) in the 
movable-bed tank and from 0.09 to 0.16 foot (2.7 to 4.9 centimeters) 
in the fixed-bed tank. The average wave height was 0.12 foot in both 
movable- and fixed-bed tanks. 

The average incident wave height for runs with cumulative times of 
375:40, 376:30, and 378:00 were 0.15, 0.15, and 0.16 foot in the fixed- 
bed tank and 0.16, 0.14, and 0.14 foot (4.9, 4.3, and 4.3 centimeters) 
in the movable-bed tank, respectively (i.e., the incident wave height 
variations were small). 

b. Wave Reflection . The reflection coefficient data determined by 
the manual method in experiments 71Y-06 and 71Y-10, are given in Table 
8. Kfl data determined by the automated method and a comparison of the 
two methods are included in the Appendix. 

(1) 1.90-Second Wave . The variation in K^ from the concrete 
slope in experiments 71Y-06 and 71Y-10 is shown in Figure 1. The K^ 
varied from 0.10 to 0„16 in experiment 71Y-06 and from 0.09 to 0.12 in 
experiment 71Y-10. In both fixed-bed tanks, the K^ increased during 
the early part of the tests and then gradually decreased. The explana- 
tion is not apparent. The reason for a higher Kp in the narrower tank 
is unknown. The variation in K^ in the fixed-bed tank indicates the 
total of the measurement error in determining K^ from the changing 
movable-bed profile. The average K^ in the fixed-bed tanks was 0.13 
in experiment 71Y-06 and 0.10 in experiment 71Y-10. Chesnutt and Galvin 
(1974) gave average K^ values between 0.03 and 0.0 7 for these experi- 
ments; however, those values were determined by the automated method 
which gives values lower by 0.04 to 0o05 (see App.). 

The variation in K/? from the movable-bed profile in experiments 
71Y-06 and 71Y-10 is shown in Figures 2 and 3. The two experiments show 
the same pattern of variation. The Kj^ during the first 10 minutes on 



Table 6 


Incident wave heights in movable-bed tanks. 


Time (hr) 


Incident wave height (ft)' 


Experiment 71Y-06 


Experiment 71Y-10 


0.3 


0.41 


0.35 


0.5 


0.39 


0.35 


0.8 


0.38 


0.34 


1.3 


0.39 


0.35 


1.8 


0.38 


0.35 


2.3 


0.40 


0.36 


3.3 


0.38 


0.36 


4.3 


0.37 


0.36 


5.3 


0.38 


0.36 


6.3 


2 


0.36 


7.3 


0.35 


0.36 


8.3 


0.37 


0.36 


9.3 


0.36 


0.35 


11.0 


0.36 


0.35 


13.0 


0.37 


0.35 


15.0 


0.37 


0.34 


17.0 


0.36 


0.34 


19.0 


0.36 


0.34 


21.0 


0.35 




23.0 


0.36 


0.34 


25.0 


0.36 


0.35 


27.0 


0.37 


0.34 


29.0 


0.38 


0.36 


31.0 


0.37 


0.36 


33.0 


0.38 


0.35 


35.0 


0.38 


0.34 


37.0 


0.38 


0.35 


39.0 


0.36 


0.34 


41.0 


0.37 




43.0 


0.37 


0.32 


45.0 


0.37 


0.35 


47.0 


0.36 


0.35 


49.0 


0.36 


0.34 


51.0 


0.38 


0.34 


53.0 


0.39 


0.35 


55.0 


0.38 


0.34 


57.0 


0.38 


0.35 


59.0 


0.38 


0.36 



Each value is an average of wave heights along the tank for run ending at indicated time. 
Data for these times were not reduced. 



Table 6. Incident wave lieights in movable-bed tanks.— Continued 



Time (hr) 


Incident wave height (ft)' 


Experiment 71Y-06 


Experiment 71Y-I0 


61.0 


0.38 


0.36 


63.0 


0.39 


0.36 


65.0 


0.38 


0.35 


67.0 


0.38 


0.35 


69.0 


0.38 


0.35 


71.0 


0.38 


0.35 


73.0 


0.37 


0.35 


75.0 


0.38 


0.34 


77.0 


0.36 


2 


79.0 


0.38 


0.35 


81.0 


0.37 


0.36 


83.0 


0.37 


0.34 


85.0 


0.36 


0.36 


87.0 


0.37 


0.35 


89.0 


0.36 


0.35 


91.0 


0.37 


0.36 


93.0 




0.35 


95.0 


0.37 


0.36 


97.0 


0.38 


0.36 


99.0 


0.38 


0.36 


104.0 


0.40 


0.36 


109.0 


0.37 


0.38 


114.0 


0.36 


0.38 


119.0 


0.36 


0.37 


124.0 


0.38 


0.38 


129.0 


0.35 


0.38 


134.0 


0.36 


0.38 


139.0 


0.36 


0.36 


144.0 


0.37 


0.38 


149.0 


0.38 


0.36 


154.0 


0.36 


0.36 


159.0 


0.37 


0.36 


164.0 


0.38 


0.36 


169.0 


0.36 


0.37 


174.0 


0.34 


0.38 


179.0 


0.34 


0.36 


184.0 


0.36 


0.37 


189.0 


0.40 


0.37 



Each value is an average of wave heights along the tank for run ending at indicated time. 
Data for these times were not reduced. 



20 



Table 6. Incident wave heights in movable-bed tanks.— Continued 



Time (hr) 


Incident wave height (ft)' 


Experiment 71Y-06 


Experiment 71Y-10 


194.0 


0.38 


0.37 


199.0 


0.40 


0.35 


204.0 


0.40 


0.38 


209.0 


0.40 


0.41 


214.0 


0.39 


0.40 


219.0 


0.36 


0.40 


224.0 


0.35 


0.38 


229.0 


0.37 


0.39 


234.0 


0.34 


0.40 


239.0 


0.39 


0.38 


244.0 


0.41 


0.38 


249.0 


0.40 


0.38 


254.0 


0.40 


0.36 


259.0 


0.38 


0.34 


264.0 


0.40 


0.33 


269.0 


0.38 


0.33 


274.0 


0.36 


0.35 


279.0 


0.35 


0.35 


284.0 


0.35 


0.34 


289.0 


0.35 


0.35 


294.0 


0.36 


0.35 


299.0 


0.34 


0.36 


304.0 


0.36 


0.34 


309.0 


0.33 


0.36 


314.0 


2 


0.36 


319.0 


0.36 


0.36 


324.0 


0.38 


0.36 


329.0 


0.40 


0.38 


334.0 


0.40 


0.36 


339.0 


0.38 




344.0 


0.38 




349.0 


0.39 




354.0 


0.39 




359.0 


0.38 




364.0 


0.35 




369.0 


0.34 




374.0 


0.32 



Each value is an average of wave heights along the tank for run ending at indicated time. 
Data for these times were not reduced. 



Table 7. Wave heights during first 10 minutes of long waves near end of experiment 71Y-06. 





Wave height (ft) 




Movable-bed tank 


Fixed-bed tank 


(miu:s) 


(avg) 


(max) 


(min) 


(avg) 


(max) 


(min) 


0:00 to 0:35^ 
0:40 to 1:20 
1:40 to 2:20 
2:40 to 3:20 
3:40 to 4:20 
4:40 to 5:20 
5:40 to 6:20 
6:40 to 7:20 
7:40 to 8:20 
8:40 to 9:20 
9:20 to 10:00 


0.131 
0.109 
0.117 
0.112 
0.112 
0.117 
0.122 
0.126 
0.121 
0.116 
0.115 


0.145 
0.122 
0.134 
0.124 
0.126 
0.132 
0.147 
0.143 
0.138 
0.132 
0.133 


0.110 
0.090 
0.100 
0.095 
0.093 
0.090 
0.108 
0.102 
0.100 
0.098 
0.094 


0.140 
0.114 

0.108 

0.114 

0.114 

0.112 


0.158 
0.121 

0.119 

0.119 

0.128 

0.128 


0.124 
0.100 

0.097 

0.093 

0.098 

0.094 


Avg2 


0.118 




0.117 





'Waves 2 to 5. 
^Excludes to 0:35 



measurement. 



22 



Table 8. 


Reflection coefficient by manual method for 


experiments 71 Y-06 and 71 Y-10. 


rime(hr) 


K/{ in Experiment 71Y-06 


Kr in Experiment 71Y-10 


Movable bed 


Fixed bed 


Movable bed 


Fixed bed 


0.3 


0.169 




0.177 




0.5 


0.127* 




0.160 




0.8 


0.108' 




0.119 




1.3 


0.113' 


0.122 


0.173 


0.088 


1.8 


0.130' 




0.134 




2.3 


0.126 




0.119 




3.3 


0.101 




0.156 




4.3 


0.095 




0.139 




5.3 


0.098 


0.138 


0.104 


0.107 


6.3 


0.132 




0.099 




7.3 


0.100 




0.092 




8.3 


0.091 




0.066 




9.3 


0.080 




0.073 




11.0 


0.097 


0.142 


0.070 


0.110 


13.0 


0.106 




0.059 




15.0 


0.081^ 




0.067 




17.0 


0.090 




0.056 




19.0 


0.097 




0.058 




21.0 


0.086 


0.142 


3 




23.0 


0.104 




0.048 


0.112 


25.0 


0.108 




0.056 




27.0 


0.092 




0.089 




29.0 


0.098 




0.095 




31.0 


0.102 


0.146 


0.070 


0.095 


33.0 


0.110 




0.053 




35.0 


0.115 




0.068 




37.0 


0.103 




0.076 




39.0 


0.088 




0.080 




41.0 


0.097 


0.130 


3 




43.0 


0.094 




0.063 


0.099 


-1.5.0 


0.099 




0.065 




47.0 


0.099 




0.066 




49.0 


0.098 




0.065 




51.0 


0.112 


0.150 


0.069 


0.102 


53.0 


0.112 




0.090 




55.0 


0.112 




0.069 




57.0 


0.106 




0.065 




59.0 


0.114 




3 




61.0 


0.086 


0.136 


0.098 


0.106 



'Out only. 
In only. 
Not analyzed by this method. 



23 



Table 8. Reflection coefficient by manual metliod for experiments 71Y-06 and 71 Y-10.— Continued 


Time (hr) 


Kr in Experiment 71Y-06 


Kr in Experiment 71 Y-10 | 


Movable bed 


Fixed bed 


1 

Movable bed 


Fixed bed 


63.0 


0.114 




0.108 




65.0 


0.108 




0.087 




67.0 


0.102 




0.103 




69.0 


0.117 




0.104 




71.0 


0.112 


0.130 


0.088 


0.119 


73.0 


0.108 




0.100 




75.0 


0.126 




0.099 




77.0 


0.102 




3 




79.0 


0.108 




0.085 




81.0 


0.090 


0.120 


0.067 


0.102 


83.0 


0.096 




0.053 




85.0 


0.100 




0.095 




87.0 


0.101 




0.078 




89.0 


0.092 




0.105 




91.0 


0.101 


0.137 


0.097 


0.121 


93.0 


3 




0.093 




95.0 


0.094 




0.101 




97.0 


0.111 




0.090 




99.0 


0.143 




0.089 




104.0 


0.126 


0.142 


0.075 


0.106 


109.0 


0.103 




0.119 




114.0 


0.100 




0.071 




119.0 


0.113 




0.078 




124.0 


0.087 




0.094 




129.0 


0.126 


0.156 


0.085 


0.109 


134.0 


0.113 




0.086 




139.0 


0.128 




0.033 




144.0 


0.112 




0.098 




149.0 


0.122 




0.102 




154.0 


0.145 


0.126 


3 


0.099 


159.0 


0.140 




0.064 




164.0 


0.134 




0.080 




169.0 


0.144 




0.067 




174.0 


0.139 




0.099 




179.0 


0.195 


0.144 


0.074 


0.092 


184.0 


0.146 




0.102 




189.0 


0.135 




0.114 




194.0 


0.145 




0.093 




199.0 


0.168 




0.093 





Not analyzed by this method. 



24 



Table 8. Reflection coefficient by manual method for experiments 71Y-06 and 71 Y-10.— Continued 



Time (hr) 


Kr in Experiment 71Y-06 


Kr in Experiment 71 Y-10 


Movable bed 


Fixed bed 


Movable bed 


Fixed bed 


204.0 


0.150 


0.150 


0.102 




209.0 


0.161 




0.131 




214.0 


0.157 




0.129 




219.0 


0.156 




0.123 




224.0 


0.215 




0.136 




229.0 


0.192 


0.147 


0.136 




234.0 


0.245 




0.138 


0.098 


239.0 


0.231 




0.131 




244.0 


0.140 




0.135 




249.0 


0.154 




0.152 




254.0 


0.162 


0.137 


0.153 


0.116 


259.0 


0.169 




0.131 




264.0 


0.169 




0.159 




269.0 


0.137 




0.141 




274.0 


0.143 




0.112 




279.0 


0.178 


0.130 


0.122 


0.106 


284.0 


0.171 




0.110 




289.0 


0.177 




0.095 




294.0 


0.186 




0.147 




299.0 


0.174 




0.156 




304.0 


0.179 


0.126 


0.137 


0.104 


309.0 


0.229 




0.108 




314.0 


0.246 




0.099 




319.0 


0.271 




0.060 




324.0 


0.234 


0.137 


0.080 




329.0 


0.132 


0.122 


0.089 


0.093 


334.0 


0.128 


0.127 


0.110 




339.0 


0.109 


0.124 






344.0 


0.107 


0.125 






349.0 


0.141 


0.125 






354.0 


0.143 


0.127 






359.0 


0.257 


0.121 






364.0 


0.184 


0.113 






369.0 


0.232 


0.109 






374.0 


0.296 


0.099 






375.3^ 


0.285 


0.338 






376.2'* 


0.360 


0.311 






377.3^* 


0.271 


0.354 







^ave period is 3.75 seconds; wave period is 1.90 seconds for all other times. 



25 



o 
o 



o 
o 



U3 

o 



>- 



o 
o 



o 

lO 



o 
o 



o 



o 

CVJ 



L 

in o "" 

— — c 

doc 



o 



26 



0.20 



0.15 



~ 0.10 





50 100 150 200 250 300 350 400 

Time ( hr) 



Figure 2. Reflection variability in movable-bed tank o£ experiment 71Y-06. 



27 



O.ZOr 




50 200 
Time ( hr ) 



300 350 



Figure 3. Reflection variability in movable-bed tank of experiment 71Y-10, 



28 



the movable-bed side is assumed to be about the same as the average K^ 
values in the fixed-bed tanks; i.e., 0.13 in the 6-foot tank and 0.10 
in the 10-foot tank. The first measured values of K^ from the movable- 
bed profile (recorded between 12 and 20 minutes) increased to 0.17 in the 
6-foot tank and 0.18 in the 10-foot tank. These are significant increases 
but not as great as inferred in Chesnutt and Galvin (1974). After the 
initial high values and for the first 10 hours, K^ varied from 0.07 to 
0.17. For an extended period of time, the K^ was relatively small 
(K^ < 0.14 for 148 hours in the 6-foot tank and < 0.13 for 210 hours in 
the 10-foot tank). For the remainder of each experiment, the K^ in- 
creased in mean value and variability, varying from 0.11 to 0.30 in 
experiment 71Y-06 and from 0.06 to 0.16 in experiment 71Y-10. 

In general, the reflection coefficient varied from 0.0 3 to 0.30, 
which is a large variation considering the generated wave conditions 
were held constant. 

(2) 3.75-Second Wave . During the 5 hours of experiment 71Y-06 
when the wave period was 3.75 seconds, the Kj^ at cumulative times of 
375:20, 376:10, and 377:20 was 0.29, 0.36, and 0.27 in the movable-bed 
tank and 0.34, 0.31, and 0.35 in the fixed-bed tank. Reflection from 
the movable bed was slightly lower on the average, but the values varied 
over a greater range. 

2. Profile Surveys . 

a. Interpretation of Contour Movement Plots . The profile surveys 
(discussed in Vol. I) measured the three space variables of onshore- 
offshore distance (station), alongshore distance (range), and elevation 
at fixed times (Table 2) during the experiment. The CONPLT method (see 
Vol. I) for presenting the data involves fixing the alongshore distance 
by selecting data from a given range and analyzing the surveys along 
that range. The surveyed distance-elevation pairs along that range are 
used to obtain the interpolated position of equally spaced depths; e.g., 
-0.1, -0.2, and -0.3 on the hypothetical profile in Figure 4(a). These 
contour positions from each survey are then plotted against time (Fig. 
4,b). 

A horizontal line in Figure 4(b) represents no change in contour 
position. An upward-sloping line indicates landward movement of contour 
position (i.e., erosion); a downward-sloping line indicates deposition. 
The slope of a line indicates the horizontal rate of erosion or deposi- 
tion at that elevation. The three x's at time t2 (Fig. 4,b) indicate 
multiple contour positions at elevation -0.2 which is shown by the inter- 
section of the dashline with profile tz in Figure 4(a). 

Three types of contour movement plots included in this study are: 

(a) The seawardmost intercepts along one range for specified depths; 

(b) the seawardmost intercepts for one selected depth along all ranges; 
and (c) all contour intercepts including multiple intercepts along one 

29 



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to 




o 
Q. 



=» 


o 




^ 


o 




o 




t/l 




v»— 


■(-> 


E 


o 


o 


»- 33 






C_3 


^■~ 






c 


+-> 




(U 


c 




E 


1 




cu 


<D 


o 


> 
o 


> 

o 

e 




s 


^ 



- C\J <£ 



— c 



O 
Q- 



csj 


^ 


O 


o 


U0!{DA3|3 





6 



30 



range, for up to 12 selected depths. The coordinate system used for 
the contour movement plots is shown in Figure 5. 

The following elevations are referred to in the discussion that 
follows: 0.2 foot (6.1 centimeters), 0.3 foot f9.1 centimeters), 0.4 
foot (12.2 centimeters), 0.5 foot (15.2 centimeters), 0.6 foot (18.3 
centimeters), 0.7 foot (21.3 centimeters), 0o8 foot (24.4 centimeters), 
0.9 foot (27.4 centimeters), 1.2 feet (36.6 centimeters), 1.4 feet (42.7 
centimeters), and 2.1 feet (64.0 centimeters). 

b. Profile Zones . Definitions of coastal engineering terms used in 
LESS reports conform to Allen (1972) and the Shore Protection Manual (SPM) 
(U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 1975) 
For the profile zones in this study, the boundary between the foreshore 
and inshore zones is defined at elevation -0o2 foot. 

The seaward edge of the inshore zone is defined as extending through 
the breaker zone. The boundary between the inshore and offshore zones 
for these experiments is at elevation -0.8 foot. 

A definition sketch of the profile zones is shown in Figure 6. The 
profile in each experiment developed in a similar sequence. Early pro- 
files (broken line in Fig. 6) had a steep foreshore, a short inshore 
zone with a longshore bar, and a gently sloping offshore zone. Later 
profiles (dashline in Fig. 6) also had a steep foreshore zone, but the 
inshore zone widened to a long, flat shelf which terminated in a rela- 
tively steep offshore zone. This development is shown by contour move- 
ment plots (Figs. 7 to 14) of the seawardmost contour intercepts for 
elevations at 0. 1-foot-depth increments from +0.2 to -2.1 feet. Figures 
7, 8, and 9 are for ranges 1, 3, and 5 in experiment 71Y-06; Figures 10 
to 14 are for ranges 1, 3, 5, 7, and 9 in experiment 71Y-10. The heavier 
lines for the -0.2- and -0.8- foot contours distinguish the three profile 
zones in the figures. In the foreshore and offshore zones the contour 
lines are close together indicating steeper slopes; in the inshore zone 
the lines are spaced farther apart indicating flatter slopes. 

(1) Foreshore Zone . Within the first hour of each experiment, 
the foreshore developed the basic shape which it maintained throughout 
experiment 71Y-10 and until the wave period was changed in experiment 
71Y-06, as shown in the contour movement plots of the foreshore zone for 
the first 10 hours of experiments 71Y-06 (Fig. 15) and 71Y-10 (Fig. 16). 
The foreshore maintained basically the same shape (see Figs. 7 to 14) but 
retreated as material was eroded from the foreshore and backshore (upward- 
sloping lines in the figures) . 

Although the contour lines of the foreshore moved together, the lines 
were not always parallel, indicating a variation in foreshore slope with 
time at each range (Figs. 7 to 14). Table 9 gives slope values at the 
SWL intercept for the regularly surveyed profiles in experiments 71Y-06 
and 71Y-10. The steepest slope was about 0.56, and the flattest slope 
was 0.08; the average slope was about 0.20. 

31 



sa5uDy 




uoi;da9|3 




<: 

_i 



LU 



LU 



O 

cr 

Q_ 



32 




(U) 1MS 9AoqD uo!|DAai3 



33 




00 



150 200 250 300 350 400 
Time ( hr) 



Figure 7. Profile changes along range I, experiment 71Y-06. 



34 




50 100 150 200 250 300 350 400 

Time ( hr) 

Figure 8. Profile changes along range 3, experiment 71Y-06. 



35 




50 100 



150 200 250 300 350 400 
Time ( hr ) 



Figure 9. Profile changes along range 5, experiment 71Y-06. 



36 




100 150 200 250 300 
Cumulative Time (iir) 



350 400 



Figure 10. Profile changes along range 1, experiment 71Y-10, 



37 




50 100 150 200 250 300 350 400 

Cumulative Time (hr) 

Figure 11. Profile changes along range 3, experiment 71Y-10. 



38 




100 150 200 250 300 350 400 

Cumulative Time (hr) 



Figure 12. Profile changes along range 5, experiment 71Y-10, 



39 




00 150 200 250 300 350 400 

Cumulative Time(hr) 



Figure 13. Profile changes along range 7, experiment 71Y-10. 



40 




50 



100 150 200 250 300 350 400 

Cumulative Time (hr) 



Figure 14. Profile changes along range 9, experiment 71Y-10, 



o 

e 




Range 5 



Range 3 



Range 1 



012 34567 8 9 10 
Cumulative Time ( hr) 

Figure 15. Comparison of initial contour movement on the foreshore 
zone in experiment 71Y-06. 



42 



-5r 



^ +5 





01 234 56789 10 
Cumulative Time (hr ) 



01 23456789 10 
Cumulative Time ( hr ) 

Figure 16. Comparison of initial contour movement on the foreshore 
zone in experiment 71Y-10. 



43 



Table 9. Slope of the beach face at the SWL intercept in experiments 71Y-06 and 71Y-10. 



Cumulative time (hr) 


Tangent of the slope 


Range 1 


Ranges 


Range 5 


Range 7 


Range 9 


71Y-06 


71Y-10 


71Y-06 


71Y-10 


76Y-06 


71Y-10 


71Y-10 


71Y-10 


0:00 


0.12 


0.08 


0.08 


0.10 


0.10 


0.06 


0.08 


0.08 


0:10 


0.20 


0.20 


0.18 


0.20 


0.22 


0.20 


0.44 


0.18 


0:25 


0.24 


0.20 


0.12 


0.18 


0.20 


0.18 


0.12 


0.18 


0:40 


0.22 


0.20 


0.20 


0.20 


0.20 


0.24 


0.18 


0.18 


1:00 


0.24 


0.20 


0.22 


0.22 


0.20 


0.20 


0.22 


0.18 


1:30 


0.16 


0.20 


0.16 


0.18 


0.20 


0.22 


0.24 


0.20 


2:00 


0.16 


0.22 


0.22 


0.24 


0.20 


0.18 


0.14 


0.18 


3:00 


0.24 


0.20 


0.22 


0.22 


0.18 


0.14 


0.14 


0.20 


4:00 


0.18 


0.14 


0.20 


0.22 


0.18 


0.18 


0.20 


0.18 


5:00 


0.12 


0.20 


0.22 


0.16 


0.18 


0.22 


0.14 


0.16 


6:00 


0.20 


0.14 


0.22 


0.20 


0.24 


0.16 


0.24 


0.18 


7:00 


0.24 


0.20 


0.24 


0.24 


0.20 


0.22 


0.20 


0.20 


8:00 


0.14 


0.20 


0.22 


0.20 


0.20 


0.20 


0.16 


0.18 


9:00 


0.44 


0.16 


0.24 


0.24 


1 


0.14 


0.18 


0.12 


10:00 


0.14 


0.20 


0.16 


0.20 


0.34 


0.20 


0.20 


0.22 


12:00 


0.20 


0.18 


0.24 


0.20 


0.22 


0.26 


0.22 


0.26 


14:00 


0.20 


0.18 


0.20 


0.26 


0.20 


0.20 


0.14 


0.20 


16:00 


0.14 


0.14 


0.14 


0.32 


0.20 


0.16 


0.22 


0.16 


18:00 


0.22 


0.20 


0.26 


0.10 


0.18 


0.20 


0.20 


0.18 


20:00 


0.10 


0.22 


0.20 


0.16 


0.18 


0.22 


0.22 


0.26 


22:00 


0.22 


0.20 


0.22 


0.18 


0.24 


0.14 


0.24 


0.22 


24:00 


0.16 


0.20 


0.24 


0.48 


0.20 


0.16 


0.14 


0.22 


26:00 


0.28 


0.22 


0.14 


0.20 


0.24 


0.20 


0.20 


0.20 


28:00 


0.20 


0.22 


0.14 


0.20 


0.26 


0.18 


0.20 


0.16 


30:00 


0.28 


0.14 


0.12 


0.18 


0.20 


0.20 


0.20 


0.10 


32:00 


0.14 


0.18 


0.14 


0.18 


0.20 


0.26 


0.12 


0.18 


34:00 


0.18 


0.14 


0.14 


0.22 


0.22 


0.20 


0.26 


0.26 


36:00 


0.16 


0.28 


0.12 


0.20 


0.22 


0.20 


0.24 


0.16 


38:00 


0.20 


0.18 


0.16 


0.20 


0.26 


0.22 


0.24 


0.20 


40:00 


0.20 


0.32 


0.12 


0.16 


0.20 


0.20 


0.18 


0.26 


42:00 


0.30 


0.28 


0.12 


0.14 


0.16 


0.26 


0.18 


0.16 


44:00 


0.18 


0.20 


0.22 


0.14 


0.24 


0.30 


0.20 


0.18 


46:00 


0.18 


0.22 


0.14 


0.18 


0.20 


0.18 


0.26 


0.20 


48:00 


0.18 


0.54 


0.24 


0.12 


0.18 


0.14 


0.30 


0.36 


50:00 


0.28 


0.22 


0.08 


0.24 


0.18 


0.32 


0.24 


0.20 


52:00 


0.22 


0.26 


0.12 


0.24 


0.28 


0.26 


0.26 


0.10 


54:00 


0.24 


0.20 


0.16 


0.10 


0.18 


0.16 


0.28 


0.18 


56:00 


0.20 


0.20 


0.12 


0.14 


0.18 


0.30 


0.36 


0.16 


58:00 


0.20 


0.26 


0.16 


0.16 


0.24 


0.18 


0.26 


0.22 


60:00 


0.20 


0.12 


0.12 


0.12 


0.26 


0.32 


0.28 


0.22 


62:00 


0.16 


0.32 


0.18 


0.12 


0.24 


0.18 


0.28 


0.16 



Suspect data. 



44 



Table 9. Slope of the beach face at the SWL intercept in experiments 71Y-06 and 71Y-10.— Continued 



Cumulative time (hr) 


Tangent of the slope 


Range 1 


Range 3 


Range 5 


Range 7 


Range 9 


71Y-06 


71Y-10 


71Y-06 


71Y-10 


71Y-06 


71Y-10 


7IY-10 


71Y-10 


64:00 


0.24 


0.26 


0.12 


0.18 


0.12 


0.22 


0.22 


0.20 


66:00 


0.22 


0.16 


0.24 


0.22 


0.18 


0.20 


0.20 


0.16 


68:00 


0.24 


0.46 


0.22 


0.12 


0.24 


0.24 


0.16 


0.18 


70:00 


0.24 


0.18 


0.22 


0.20 


0.24 


0.14 


0.16 


0.18 


72:00 


0.18 


0.26 


0.14 


0.14 


0.20 


0.12 


0.20 


0.20 


74:00 


0.18 


0.20 


0.18 


0.12 


0.24 


0.18 


0.20 


0.16 


76:00 


0.20 


0.26 


0.20 


0.28 


0.20 


0.26 


0.26 


0.18 


78:00 


0.26 


0.26 


0.14 


0.14 


0.22 


0.24 


0.18 


0.14 


80:00 


0.20 


0.26 


0.26 


0.12 


0.16 


0.18 


0.22 


0.24 


82:00 


0.16 


0.18 


0.26 


0.38 


0.24 


0.44 


0.20 


0.18 


84:00 


0.52 


0.50 


0.30 


0.12 


0.40 


0.16 


0.22 


0.20 


86:00 


0.20 


0.24 


0.14 


0.12 


0.16 


0.42 


0.22 


0.24 


88:00 


0.32 


0.34 


0.30 


0.10 


0.20 


0.18 


0.22 


0.18 


90:00 


0.20 


0.24 


0.20 


0.14 


0.24 


0.22 


0.22 


0.20 


92:00 


0.20 


0.26 


0.14 


0.16 


0.18 


0.16 


0.20 


0.24 


94:00 


0.36 


0.18 


0.10 


0.22 


0.24 


0.20 


0.18 


0.20 


96:00 


0.16 


0.22 


0.26 


0.14 


0.32 


0.14 


0.12 


0.18 


98:00 


0.28 


0.20 


0.22 


0.16 


0.28 


0.28 


0.16 


0.22 


100:00 


0.22 


0.28 


0.26 


0.16 


0.18 


0.36 


0.22 


0.18 


105:00 


0.14 


0.16 


0.22 


0.14 


0.22 


0.22 


0.14 


0.20 


110:00 


0.22 


0.22 


0.20 


0.24 


0.18 


0.22 


0.24 


0.28 


115:00 


0.32 


0.10 


0.30 


0.20 


0.26 


0.10 


0.20 


0.18 


120:00 


0.18 


0.20 


0.20 


0.24 


0.20 


0.18 


0.20 


0.20 


125:00 


0.22 


0.24 


0.24 


0.16 


0.20 


0.16 


0.24 


0.20 


130:00 


0.20 


0.22 


0.14 


0.20 


0.22 


0.18 


0.22 


0.16 


135:00 


0.24 


0.24 


0.24 


0.14 


0.20 


0.12 


0.24 


0.20 


140:00 


0.20 


0.14 


0.20 


0.20 


0.18 


0.14 


0.20 


0.10 


145:00 


0.20 


0.16 


0.20 


0.20 


0.22 


0.38 


0.38 


0.32 


150:00 


0.22 


0.12 


0.20 


0.26 


0.18 


0.20 


0.24 


0.22 


155:00 


0.18 


0.20 


0.22 


0.20 


0.20 


0.26 


0.24 


0.08 


160:00 


0.20 


0.20 


0.20 


0.18 


0.18 


0.18 


0.14 


0.24 


165:00 


0.24 


0.18 


0.18 


0.26 


0.14 


0.12 


0.24 


0.16 


170:00 


0.24 


0.22 


0.24 


0.24 


0.12 


0.14 


0.24 


0.18 


175:00 


0.18 


0.18 


0.24 


0.22 


0.28 


0.18 


0.44 


0.20 


180:00 


0.20 


0.20 


0.28 


0.16 


0.18 


0.16 


0.32 


0.16 


185:00 


0.16 


0.22 


0.20 


0.14 


0.12 


0.14 


0.20 


0.18 


190:00 


0.18 


0.22 


0.22 


0.32 


0.18 


0.14 


0.20 


0.22 


195:00 


0.18 


0.24 


0.20 


0.18 


0.10 


0.14 


0.20 


0.14 


200:00 


0.14 


0.16 


0.12 


0.18 


0.14 


0.20 


0.56 


0.24 


205:00 


0.22 


0.24 


0.20 


0.20 


0.20 


0.14 


0.18 


0.14 


210:00 


0.18 


0.22 


0.18 


0.22 


0.10 


0.22 


0.12 


0.18 



45 



TaUe 9. Slope of the beach face at the SWL intercept in experiments 71Y-06 and 71Y-10.— Continued 



Cumulative time (hr) 






Tangent of the slope 








Range 1 


Range 3 


Range 5 


Range 7 


Range 9 


71Y-06 


71Y-10 


71Y-06 


71Y-10 


71Y-06 


71Y-10 


71Y-10 


71Y-10 


215:00 


0.14 


0.22 


0.16 


0.14 


0.18 


0.16 


0.14 


0.22 


220:00 


0.22 


0.20 


0.16 


0.20 


0.18 


0.24 


0.14 


0.16 


225:00 


0.20 


0.18 


0.16 


0.22 


0.18 


0.18 


0.16 


0.22 


230:00 


0.20 


0.20 


0.18 


0.16 


0.18 


0.18 


0.16 


0.12 


235:00 


0.20 


0.18 


0.18 


0.20 


0.18 


0.12 


0.20 


0.56 


240:00 


0.18 


0.06 


0.14 


0.18 


0.20 


0.20 


0.18 


0.20 


245:00 


0.14 


0.18 


0.20 


0.18 


0.14 


0.14 


0.16 


0.20 


250:00 


0.22 


0.18 


0.16 


0.16 


0.22 


0.16 


0.22 


0.34 


255:00 


0.16 


0.28 


1 


0.18 


0.16 


0.20 


0.16 


0.18 


260:00 


0.18 


0.20 


0.12 


0.18 


0.28 


0.10 


0.20 


0.18 


265:00 


0.22 


0.16 


0.16 


0.20 


0.22 


0.18 


0.18 


1 


270:00 


0.18 


0.18 


0.16 


0.16 


0.16 


0.10 


0.18 


0.20 


275:00 


0.18 


0.18 


0.16 


0.24 


0.14 


0.08 


0.18 


0.14 


280:00 


0.20 


0.20 


0.20 


0.18 


0.18 


0.08 


0.24 


0.24 


285:00 


0.14 


0.20 


0.22 


0.14 


0.16 


0.20 


0.12 


0.18 


290:00 


0.20 


0.20 


0.24 


0.22 


0.44 


0.10 


0.20 


0.20 


295:00 


0.14 


0.22 


0.18 


0.24 


0.18 


0.10 


0.20 


0.20 


300:00 


0.18 


0.16 


0.30 


0.18 


0.18 


0.10 


0.10 


0.18 


305:00 


0.18 


0.16 


0.16 


0.30 


0.08 


0.16 


0.16 


0.18 


310:00 


0.16 


0.16 


0.20 


0.24 


0.26 


0.14 


0.18 


0.16 


315:00 


0.14 


0.22 


0.18 


0.14 


0.16 


0.16 


0.24 


0.14 


320:00 


0.16 


0.22 


0.12 


0.20 


0.20 


0.16 


0.14 


0.14 


325:00 


0.16 


0.14 


0.16 


0.18 


0.18 


0.16 


0.12 


0.18 


330:00 


0.16 


0.26 


0.16 


0.16 


0.14 


0.20 


0.14 


0.18 


335:00 


0.16 


0.26 


0.16 


0.28 


0.08 


0.16 


0.16 


0.20 


340:00 


0.16 




0.16 




0.40 








345:00 


0.14 




0.16 




0.18 








350:00 


0.18 




0.22 




0.22 








355:00 


0.18 




0.16 




0.20 








360:00 


0.16 




0.18 




0.18 








365:00 


0.26 




0.16 




0.18 








370:00 


1 




0.24 




0.18 








375:00 


0.14 




0.16 




0.20 








375:10 


0.26 




0.10 




0.18 








375:40 


0.12 




0.14 




0.16 








376:30 


0.12 




0.18 




0.18 








378:00 


0.12 




0.12 




0.18 








380:00 


0.28 




0.10 




0.16 








Avg 


0.20 


0.21 


0.18 


0.19 


0.20 


0.19 


0.21 


0.19 


Overall avg 




0.20 













Suspect data. 



46 



The lateral variation in the slope of the foreshore developed as a 
result of concentrations of backwash, which created gullies or flatter 
slopes. The flow of the wave uprush and backrush for the same wave con- 
ditions that shaped the foreshore is discussed in Volume II (Chesnutt 
and Stafford, 1977) . 

Near the end of experiment 71Y-10, the changes in the foreshore zone 
became more complex (Fig. 17) , Erosion of the backshore was greatest 
along the outside ranges. A large concentration of backwash occurred 
along the center of the tank and at various times was skewed toward 
different sides of the tank. The steepest slopes were not perpendicular 
to the wave approach. A greater lateral variation occurred in the fore- 
shore zone of the 10-foot tank than in the 6-foot tank. 

The shoreline (0 contour) movement along the several ranges of the 
two experiments is compared in Figure 18. The slope of the contour 
indicates the shoreline recession rate. Because the slope of the back- 
shore was 0.10 (and not flat), the volume rate of erosion was not con- 
stant and increased at a rate proportional to the square of the shore- 
line recession rate. The lateral variations discussed previously are 
also shown in the top set of curves in Figure 18 for experiment 71Y-10. 
The rate of shoreline recession increased along the sides of the tank, 
as indicated by the widening of the family of curves, with range 5 on 
the bottom and ranges 1, 7, and 9 on the top. 

During the first 15 hours the shoreline retreated 1.7 feet (0.52 
meter) in experiment 71Y-06 and 2 feet (0.61 meter) in experiment 71Y- 
10. The average erosion rate in experiment 71Y-06 between 15 and 375 
hours was 0.025 foot (0.76 centimeter) per hour. The rate along range 
5 in experiment 71Y-10 between 15 and 335 hours was 0.016 foot (0.49 
centimeter) per hour. At 205 hours the erosion rate along the outside 
ranges increased from 0.016 to 0.025 foot per hour. 

(2) Inshore Zone . Within the first hour of each experiment, a 
longshore bar developed at the shoreward end of the inshore zone between 
elevations -0.2 and -0.5 foot. Later, but at different times, the bar 
disappeared, and the area between elevations -0.2 and -0.5 foot steepened, 
and a long, flat shelf developed between elevations -0.5 and -0.8 foot. 
The shelf continued to grow in length for the remainder of the experi- 
ments. Changes in the inshore zone are divided into an inner region 
(between elevations -0.2 and -0.5 foot) and an outer region (between 
-0.5 and -0.8 foot) . 

(a) Inner Region (Experiment 71Y-06) . The movement of all 
contour intercepts in the inshore zone along the three ranges for experi- 
ment 71Y-06 is shown in Figures 19, 20, and 21; the movement of selected 
individual contours along the three ranges is compared in Figure 22. 

During the first 10 minutes of testing a longshore bar formed at sta- 
tion +4. For the first 200 hours the bar crest elevation varied between 
-0.3 and -0.4 foot, and the bar moved in the shoreward direction at an 



47 




stjSfv.-. :l ■ ::M.^Bi^^ 



i / 



\ \ \ 



A 



Scorp 

Berm or Ridge Crest 

•^ Poth Line of Backwosh 



Figure 17. Shape of foreshore zone near end of experiment 71Y-10. 



48 




o 


t/) 1 


o 


•H >H 




U --1 




cti r-- 




Cl4 




6 -O 




° C 



lo o u") m Q 

{\^) |d93J9jU| "IMS IDUlbUQ UJOJ| aOUDISIQ 



49 



-20 



^-15 



lultiple Contour Positions (ft) 

o - 0. I #-06 

o - 0.2 ♦ -0 7 

» -0.3 X -0.8 

+ -04 1 -0.9 
>c -0.5 




50 100 150 200 250 300 350 

Cumulative Time ( hr ) 



400 



Figure 19. Changes in the inshore zone along range 1, experiment 71Y-06, 



50 



-20 



^ -15 



Multiple Contour Positions (ft 

o - I #-0 6 

9-0.2 ♦ -0.7 

* - 3 n -0.8 

+ - 0.4 1 -0.9 




50 100 150 200 250 300 
Cumulative Time ( hr) 



350 400 



Figure 20. Changes in the inshore zone along range 3, experiment 71Y-06, 



51 



■20 r 



15 



^_ 
O 

e 

o 



<^ 10 



Q 15 



20 



lultiple Contour Positions (ft] 

D - 0. 1 ♦ -0.6 

a -0.2 ♦ -0.7 
* -0.3 ^ -0.8 

+ - 0.4 I -0.9 

X -0.5 




50 100 150 200 250 300 350 

Cunnulative Time ( hr) 



400 



Figure 21. Changes in the inshore zone along range 5, experiment 71Y-06. 



52 



-0.3-£t contour 




Range 01 
Range 03 
Range 05 



150 200 250 300 350 

Cumulative Time ( hr) 



4C0 



Figure 22. Comparison of the -0.3-, -0.4-, -0.6-, -0.7-, and -0.8-foot 
contour movements in experiment 71Y-06. 



53 



average rate o£ 0.018 foot (0.55 centimeter) per hour. After 205 hours 
the bar was eroded, as indicated by the shoreward movement of the -0.3-, 
-0.4-, and -0.5-foot contours in Figures 19, 20, and 21. The inner region 
maintained a fairly steep slope from 220 to 375 hours (shown by the close 
spacing of the -0.2-, -0.3-, -0.4-, and -0.5-foot contours in Figs. 19, 
20, and 21). 

The movements of the -0.3- and -0.4- foot contours along the three 
ranges are compared in Figure 22. No lateral variation apparently 
occurred in the changes of the inner region, other than minor differences 
in the bar crest elevation between and 200 hours (see the different 
positions of the -0.3- foot contour in Fig. 22). 

(b) Outer Region (Experiment 71Y-06) . Although some deposi- 
tion occurred during the first 2 hours which moved the -0.6-, -0.7-, and 
-0.8-foot contours 1 foot in the seaward direction, the outer region 
remained unchanged for 175 hours. After 175 hours the -0.7- and -0.8-foot 
contours began moving in the seaward direction as material was deposited 
at the seaward edge of the inshore zone, and the -0.6-foot contour began 
moving in the shoreward direction as erosion of the bar began in the inner 
region. After 200 hours the outer region became a long, relatively flat 
shelf, as shown by the divergence of the -0.8- and -0.5-foot contours. 

The several intercepts of the -0.6- and -0.7- foot contours indicate 
several small bars and troughs. Figure 23 shows the appropriate contour 
intercepts connected and the bars and troughs indicated by shaded areas. 

The length of the shelf continued to increase as material eroded from 
the foreshore and was deposited offshore. The largest fluctuations in 
contour position were two temporary shifts of about 10 and 12 feet in 
the -0.7-foot contour position (Figs. 19, 20, and 21). The same shifts 
occurred simultaneously at all three surveyed ranges (Fig. 22), showing 
that this change was two-dimensional, and suggesting that significant net 
sand transport occurred across the inshore zone during these periods. The 
large shifts in the -0.7- foot contour represent an increase in the depth 
over the inshore zone. 

The -0.6-, -0.7-, and -0.8-foot contours indicate no significant 
lateral variations (Fig. 22). The variations in the -0.6-foot contour 
show that the bar crest elevation reached -0.6 foot at different times 
along the different ranges. 

(c) Inner Region (Experiment 71Y-10) . Contour movement in 
the inshore zone along the five ranges for experiment 71Y-10 is shown in 
Figures 24 to 28. Movements of the seawardmost intercepts along ranges 
1, 3, 5, 7, and 9 are compared at depths of -0.3, -0.4, -0.6, -0.7, and 
-0.8 foot in Figure 29. 

Within the first 10 minutes a longshore bar formed at station +4. The 
bar remained stationary for the first 100 hours, while the crest elevation 
varied between -0.3 and -0.4 foot, as shown by the movement of the -0.3- 
foot contour in Figure 29. Erosion of the longshore bar began first along 



54 



lultiple Contour Positions (ft' 





-20 




-15 


— 


-10 


Q. 
CD 
<_> 


- 5 


_l 

CO 




o 

c: 

en 






ei - 0. 1 


* -0.6 


-0.2 


♦ -0.7 


* -0.3 


"t -0.8 


♦ - 0.4 


2 -0.9 


X -0.5 




pli;*;liKi:j 


Bar 








Trougti 




50 100 150 200 250 300 350 
Cumulative Time (hr) 

Figure 23. Movement of bars and troughs along range 3 in experiment 



400 



71Y-06, 



55 



-20 



^ -15 



-10 



O 



15 - 



20 



Multiple Contour Positions (ft' 






- 0.1 


« 


-0.6 


a 


- 0.2 


♦ 


-0.7 


» 


-0.3 


K 


-0.8 


+ 


- 0.4 


I 


-0.9 


X 


-0.5 








■0,1 ft 
■0.2 ft 
•0.3 ft 

■0.4 ft 
■0.5 ft 
■0.6 ft 



•0 8 ft 
0.9 ft 



50 100 150 200 250 300 350 400 

Cumulative Time ( l^r) 



Figure 24. Changes in the inshore zone along range 1, experiment 71Y-10, 



56 



-20 r 



r -15 



10 - 



-J -5 - 



o 

E 



15 - 



20 



Multiple Conto 


ur Positions 


(ft) 










- 0. 1 


# -0.6 












-0.2 


♦ -0.7 












* -0.3 


n -0.8 












+ - 0.4 


1 -0.9 












X -0.5 










^^\ ^— -ISTToT 


/ -0.1 ft 

4—' 


' ^^ 


^/Tif 


% 


i 


^ 




5L -0.3 ft 
'3/ -0.4 ft 
^ -0.5 ft 

--^1 -0.6 ft 




f}jyir-f 


/V 


/\ 




r v/ T + . *f 




iv^^^V^ 


^ 


*3 


r^ 




♦x 


^^^Ll >H 


^ ?^!it| ^ 


TV 


V 


^ :-:J 


!/ Wf 




^^^^^&^ 


--;XCiw 




\ .--/J^ 


jMhl 


'x 


%^^h^rh 


s 


♦ / 


$ 




#1:4 i 




%Jy^\MTJs.ALrJ\/ftJ^ 


♦yW- -sy^^ 


""^ ♦ 






» ♦ ^ ♦ 


X 


♦ «¥y*v¥^i*^ 


^:linr-x ♦ 


♦ 




»7 


^ ♦♦♦ ■»♦> 


1 


>*VV-V\^^^-"^'^" 


^-^^ ^ v^ 


-^^ 


V 


v^y^ 


*♦♦♦♦♦♦ 




-^^^JvT^ 




A 

.'~- 


X 


♦♦ ♦ 


♦ -0.7 ft 




1 










^^^^^•''Ay 


^ ^/V 


V " 












\_r^ 


*"« -0.8 ft 


1 


1 1 




1_ 


1 


\ 

1 


"^^ -0.9ft 

1 1 



50 100 150 200 250 300 350 400 

Cumulative Time ( hr) 

Figure 25. Changes in the inshore zone along range 3, experiment 71Y-10, 



57 




100 150 200 250 300 350 400 
Cumulative Time (hr) 

Figure 26. Changes in the inshore zone along range 5, experiment 71Y-10. 



58 



-20 r 



^-15 




100 150 200 250 300 350 400 
Cumulative Time (hr) 

Figure 27. Changes in the inshore zone along range 7, experiment 71Y-10, 



59 



-20 



15 



O 

E 



10 



Q 15 



20 



Multiple Contour Positions (ft) 



o 


- 0.1 


* 


-0.6 





-0.2 


♦ 


-0.7 


s 


-0.3 


X 


-0.8 


+ 


- 0.4 


z 


-0.9 


X 


-0.5 








0.1 ft 
0.2 ft 
0.3ft 
0.4 ft 
0.5 ft 



0.8 ft 
0.9 ft 



50 100 150 200 250 300 350 400 
Cumulative Time ( hr) 



Figure 28. Changes in the inshore zone along range 9, experiment 71Y-10, 



60 




Range 01 

Range 03 

Range 05 

Range 07 

Range 09 



150 200 250 

Cumulative Time ( hr) 



350 400 



Figure 29. Comparison o£ the -0.3-, -0.4-, -0.6-, -0.7-, and 0.8-foot 
contour movements in experiment 71Y-10. 



range 9 at 115 hours, advanced across the tank, and began along range 1 
at 190 hours (shov\m by movement of the several -0.4-£oot contours in 
Fig. 29) . After the bar eroded, the inner region maintained a fairly 
steep slope for the duration of the experiment. 

(d) Outer Region (Experiment 71Y-10) . Although some deposi- 
tion occurred during the first 5 hours which moved the -0.6-, -0.7-, and 
-0.8-foot contours 2 feet in the seaward direction, the outer region re- 
mained unchanged until after 100 hours. The development of the flat shelf 
in the outer region followed erosion of the longshore bar in the inner 
region, as indicated by the movement of the -0.6-foot contour along the 
five ranges in Figure 29. The shelf began developing first along range 
9 at 115 hours and along range 1 at 215 hours. The shelf widened as 
material was eroded from the foreshore and deposited in the offshore. 
At different times along the five ranges, the seawardmost -0.7-foot 
contour made significant shifts, first along ranges 7 and 9 and later 
along ranges 1, 3, and 5. These shifts correlate with the progressive 
development of the shelf across the tank from range 9 to range 1 and 
indicate a net movement of sediment across the inshore zone. 

(3) Offshore Zone . 

(a) Experiment 71Y-06 . The movement of contours in the 
offshore zone is shown in Figures 7, 8, and 9 for ranges 1, 3, and 5. 
The offshore zone developed from the initial 0.10 slope to a relatively 
steep slope as a result of the deposition of material seaward of the 
breaker. 

During the first 10 hours, more deposition occurred at the higher 
elevations, but after that time, all the contour movements were parallel 
in the offshore zone until 200 hours. Between 200 and 250 hours and 
between 315 and 340 hours, significant deposition occurred again at the 
higher elevations, increasing the offshore zone slope. 

The movement of contours at the three ranges for elevations of -0.9, 
-1.2, and -2.1 feet is compared in Figure 30. No lateral variations 
occurred in the movements of the -1.2- and -2.1-foot contours, and only 
minor variations in the movement of the -0.9-foot contour. 

(b) Experiment 71Y-10 . Figures 10 to 14 show the contour 
movements in the offshore zone for the five ranges in experiment 71Y-10. 
During the first 10 hours sediment was deposited between depths of 0.9 
and 1.4 feet. After 10 hours the contours along a given range were par- 
allel (indicating uniform deposition at all depths), but there was vari- 
ation from one range to the next. Along range 9 the contours moved 
seaward at an average rate of 0.025 foot per hour. Along range 5 the 
offshore remained essentially stationary for the next 100 hours (until 
110 hours) and then began prograding seaward at an average rate of 0.024 
foot (0.73 centimeter) per hour; along range 1, the offshore remained 
stable until 170 hours and then prograded seaward at a rate of 0.019 
foot (0.58 centimeter) per hour. 

62 




o 


tn u 


o 


• H <U 




U CI, 




03 X 




Qh 0) 



o mo 

(il) idaojaiu] "|/v\S IDuiDuq luoj| 90UD|sia 



63 



The movement of contoiars at the five ranges for elevations of -0.9, 
-1.2, and -2.1 feet is compared in Figure 31. The lateral variation in 
the movement of the offshore zone is quite noticeable at -1.2 and -2ol 
feet; e.g., the positions of the -2 = 1-foot contour at 335 hours are sta- 
tions 25.6, 26.3, 27.0, 27.2, and 27.5 feet along ranges 1, 3, 5, 7, and 
9, respectively. 

The offshore slope, measured between the -0.9- and -2.1-foot contours, 
varied from 0.113 along range 1 to 0.098 along range 9. 

c. Profile Adjustment Under 3.75-Second Wave . For 375 hours, the 
profile in experiment 71Y-06 was attacked by a fairly steep (H^/L^ = 
0.021) wave. Then, for the next 5 hours, the profile was subjected to 
a low (Hq/Lq = 0.002) wave. As expected, this low wave moved sediment 
back toward the shoreline and onto the foreshore. The profiles along 
range 3 at the beginning and the end of this subexperiment are compared 
in Figure 32. The low wave flattened out the many small bars and troughs 
within the inshore zone and deposited material on the foreshore. Move- 
ment of the seawardmost contour intercepts during the 5-hour period is 
plotted in Figures 33, 34, and 35. These plots indicate deposition at 
elevations 0.2, 0.1, 0, -0.1, -0.2, and -0.5 foot, and erosion at eleva- 
tions -0.3, -0.4, -0.6, -0.7, and -0.8 foot. A photo in Figure 36 shows 
deposition on the foreshore zone at 380 hours. After the experiment was 
stopped, a trench was dug along the middle of the test area. The light- 
toned sediment on top in the photo is the deposition during the 5 hours 
of long-period waves. 

3. Sediment-Size Distribution . 

The sand for these experiments was the same sand used by Savage (1959, 
1962) and Fairchild (1970a, 1970b). Because the samples collected in this 
study were surface samples, and therefore subject to winnowing action, the 
median grain size may have been slightly less when Savage and Fairchild 
performed their tests. The data reported here are the Rapid Sediment 
Analyzer (RSA) values, which were generally 0.04 millimeter greater than 
that determined by the dry sieve method (see Vol. I). The RSA values are 
used here only because all the data were reduced by this method. 

Tables 10 and 11 give the sediment-size analysis results from experi- 
ments 71Y-06 and 71Y-10. Sediment samples were collected along the pro- 
file before the beginning of experiment 71Y-06, and the results of the 
size analysis are given in Table 10. The average median grain size was 
0.27 millimeter, which is assiamed to represent the median grain size, 
dsoj for the unsorted sediment in both experiments. 

a. Experiment 71Y-06 . A summary of the median grain sizes for ex- 
periment 71Y-06, including the mean of the medians, range of values, and 
the number of samples within each profile zone for each time, is given in 
Table 12. The median grain size on the foreshore remained above 0.27 
millimeter (with one exception). This value of 0.27 was the same as the 
mean of the medians of all san^jles from the beach at hours. The increase 



64 



o 
-I o 




o 




^ 




(-) 


cu 


1 


■M 


rvl 


> 




C 












o 


o 
1 


e 

•H 








f-l 




E 




01 



e > 



(H) ^ci83J8|U| IMS |DU|5nO lilOJ^ aOUDiSIQ 



65 



c? 



-2 - 



-4 



.380 hr 



375 hr 




Datum - Beach Intersect 



8 16 24 32 

Distance from Original SWL Intercept (ft) 



40 



Figure 32. Comparison o£ profiles along range 3 at 375 and 380 hours in 
experiment 71Y-06. 



66 



-I5r- 



■10 



-5 




o 

E 



15 



20 



25 



30 



375 376 377 378 

Cumulative Time (hr) 



379 



02 ft 



-0.6 



-0.8 



- 1.0 
-1.2 

- 1.4 



380 



Figure 33. Profile changes along range 1 in experiment 71Y-06 between 375 and 
380 hours. 



67 



■15 



-10 



- 5 




O 

£ 



10 



20 



25 



30 



375 376 377 ' 378 379 

Cumulative Time (hr) 



2ft 



- 


1 .0 


- 


1 .2 




1 4 


- 


1 .6 


- 


1 e 


- 


2.0 ft 



380 



Figure 34. Profile changes along range 3 in experiment 71Y-06 between 375 
and 380 hours. 



68 




- 5 




o 

E 



15 



20 



25 



30 



375 376 377 378 379 

Cumulative Time (hr) 



0.8 
I .0 




380 



Figure 35. Profile changes along range 5 in experiment 71Y-06 between 
375 and 380 hours. 



69 




<u 


c 


> 


(U 


oj 


e 


S 


•H 




U 


00 


<U 


c 


Pi 



70 



Table 10. Sediment-size analy 


sis at various 


liours for experiment 71Y-06 


. 




Range 2 


Range 4 


Station 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 



OHr 



-6 


0.30 


0.28 


1.84 


0.30 


0.27 


1.87 


-4 


0.30 


0.26 


1.99 


0.30 


0.26 


1.93 


-2 


0.20 


0.26 


1.96 


0.20 


0.28 


1.84 





-0.10 


0.26 


1.94 


-0.10 


0.26 


1.95 


2 


-0.20 


0.26 


1.92 


-0.20 


0.26 


1.93 


4 


-0.30 


0.25 


1.99 


-0.30 


0.27 


1.92 


6 


-0.45 


0.26 


1.94 


-0.45 


0.25 


2.03 


8 


-0.70 


0.26 


1.93 


-0.70 


0.27 


1.90 


10 


-1.00 


0.27 


1.92 


-1.00 


0.28 


1.83 


12 


-1.15 


0.26 


1.97 


-1.15 


0.26 


1.95 


14 


-1.30 


0.27 


1.87 


-1.30 


0.26 


1.94 


16 


-1.60 


0.26 


1.97 


-1.60 


0.28 


1.91 


18 


-1.75 


0.26 


1.94 


-1.75 


0.28 


1.90 


20 


-2.00 


0.27 


1.87 


-2.00 


0.28 


1.84 


22 


-2.33 


0.26 


1.94 


-2.33 


0.28 


1.82 



26 Hr 



-6 


0.30 


0.28 


1.84 


0.30 


0.24 


2.08 


-4 


0.30 


0.29 


1.76 


0.30 


0.28 


1.86 


-2 


0.00 


0.31 


1.71 


0.05 


0.32 


1.67 





-0.20 


0.29 


1.77 


-0.10 


0.31 


1.71 


2 


-0.28 


0.28 


1.83 


-0.32 


0.27 


1.88 


4 


-0.40 


0.30 


1.73 


-0.60 


0.30 


1.75 


6 


-0.60 


0.27 


1.91 


-0.50 


0.29 


1.81 


8 


-0.75 


0.26 


1.95 


-0.70 


0.28 


1.86 


10 


-0.90 


0.25 


2.02 


-0.90 


0.25 


2.00 


12 


-1.15 


0.24 


2.07 


-1.08 


0.25 


1.99 


14 


-1.40 
-1.60 


0.24 
0.24 


2.07 
2.05 


1 






16 


-1.50 


0.23 


2.10 


18 


-1.75 


0.24 


2.08 


-1.75 


0.24 


2.05 


20 


-2.00 


0.24 


2.05 


-1.95 


0.23 


2.11 


22 


-2.33 


0.25 


2.02 


-2.33 


0.26 


1.93 


24 


-2.33 


0.30 


1.75 


-2.33 


0.27 


1.90 



Samples not collected at these stations. 



71 



Table 10. Sediment-size analysis at various hours for experiment 71 Y-06.— Continued 



Station 



Range 2 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



Range 4 



Elevation 
(ft) 



Median 
(mm) 



50 Hr 



100 Hr 



Samples not collected at these stations. 
NOTE.- At 100 hours, one sediment sample was taken on range 1 at station 
median grain size, 0.25 millimeter (1.99 phi), elevation —1.65 feet. 



19; 



-7 


0.30 


0.27 


1.87 


0.30 


0.26 


1.92 


-5 


0.30 


0.26 


1.97 


0.30 


0.35 


1.54 


-3 


0.10 


0.28 


1.83 


0.00 


0.31 


1.69 


-1 


-0.10 


0.31 


1.69 


-0.10 


0.31 


1.71 


1 


-0.15 


0.30 


1.75 


-0.30 


0.30 


1.73 


3 


-0.30 


0.29 


1.79 


-0.50 


0.30 


1.76 


5 


-0.55 


0.28 


1.85 


-0.50 


0.29 


1.77 


7 


-0.60 


0.28 


1.85 


-0.65 


0.29 


1.77 


9 


-0.85 


0.26 


1.96 


-0.75 


0.29 


1.80 


11 


-0.95 


0.25 


1.98 


-0.95 


0.27 


1.90 


13 


-1.18 


0.25 


2.00 


-1.15 


0.24 


2.08 


15 


-1.40 


0.24 


2.04 


-1.37 


0.26 


1.97 


17 


-1.65 


0.23 


2.12 


-1.60 


0.24 


2.07 


19 


-1.80 


0.23 


2.11 


-1.80 


0.24 


2.06 


21 


-2.00 


0.24 


2.05 


-2.04 


0.23 


2.09 


23 


-2.33 


0.25 


2.01 


-2.33 


0.26 


1.96 



-7 


0.30 


0.27 


1.88 


0.30 


0.30 


1.76 


-5 


0.20 


0.25 


2.00 


0.25 


0.28 


1.84 


-3 
-1 


1 






-0.10 
-0.20 


0.35 
0.31 


1.51 
1.70 


-0.23 


0.30 


1.75 


1 


-0.40 


0.31 


1.70 


-0.30 


0.33 


1.61 


3 


40 


0.32 
0.28 


1.62 
1.83 








5 


-0.61 


-0.52 


0.29 


1.80 


7 


-0.66 


0.28 


1.83 


-0.66 


0.28 


1.85 


9 


-0.85 


0.26 


1.93 


-0.82 


0.27 


1.91 


11 


-0.95 


0.26 


1.96 


-0.95 


0.26 


1.96 


13 


-1.12 


0.25 


2.02 


-1.10 


0.24 


2.03 


15 


-1.32 


0.24 


2.07 


-1.32 


0.25 


2.01 


17 


-1.47 


0.25 


2.00 


-1.47 


0.26 


1.96 


19 


-1.65 


0.25 


2.00 













72 



Table 10. Sediment-size analysis at various hours for experiment 


71Y-06.-Continued 




Range 2 


Range 4 


Station 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 



200 Hr 



-9 


0.30 


0.28 


1.85 


0.30 


0.27 


1.91 


-7 


0.20 


0.28 


1.85 


0.30 


0.27 


1.92 


-5 


-0.12 


0.31 


1.67 


-0.12 


0.28 


1.85 


-3 


-0.20 


0.32 


1.67 


-0.25 


0.31 


1.67 


-1 


-0.40 


0.34 


1.56 


-0.50 


0.34 


1.57 


-1 
3 
5 
7 
9 


1 






40 


31 


1 67 








n 6? 


^1 


1 69 








66 


31 


1 71 








70 


29 


1 76 


-0.77 


0.30 


1.76 


-0.80 


0.29 


1.77 


11 


-0.90 


0.28 


1.86 


-0.85 


0.28 


1.86 


13 


-0.98 


0.27 


1.87 


-0.95 


0.28 


1.85 


15 


-1.08 


0.26 


1.95 


-1.10 


0.27 


1.89 


17 


-1.30 


0.26 


1.94 


-1.30 


0.27 


1.90 


19 


-1.40 


0.26 


1.95 


-1.45 


0.26 


1.93 


21 


-1.60 


0.24 


2.09 


-1.65 


0.26 


1.93 



300 Hr 



-13 


0.30 


0.27 


1.90 


0.30 


0.28 


1.82 


-11 


0.30 


0.34 


1.58 


0.30 


0.34 


1.56 


-9 


0.05 


0.35 


1.50 


0.15 


0.33 


1.59 


-7 


-0.20 


0.34 


1.55 


-0.10 


0.41 


1.29 


-5 


-0.45 


0.32 


1.66 


-0.48 


0.30 


1.73 


-3 


-0.50 


0.27 


1.91 


-0.52 


0.25 


1.99 


-1 


-0.60 


0.29 


1.80 


-0.65 


0.28 


1.82 


1 


-0.60 


0.28 


1.84 


-0.80 


0.31 


1.71 


3 


-0.80 


0.28 


1.86 


-0.80 


0.28 


1.83 


5 


-0.70 


0.29 


1.8t) 


-0.80 


0.27 


1.89 


7 


-0.70 


0.27 


1.92 


-0.82 


0.28 


1.82 


9 


-0.70 


0.28 


1.82 


-0.60 


0.29 


1.80 


11 


-0.70 


0.28 


1.84 


-0.70 


0.27 


1.88 


13 


-0.70 


0.30 


1.76 


-0.70 


0.29 


1.78 


15 


-0.80 


0.28 


1.85 


-0.84 


0.26 


1.95 


17 


-0.85 


0.26 


1.94 


-0.92 


0.28 


1.83 


19 


-1.10 


0.25 


2.00 


-1.10 


0.28 


1.86 


21 


-1.35 


0.24 


2.04 


-1.35 


0.25 


1.99 



Samples not collected at these stations. 



73 



Table 10. Sediment-size analysis at 


various hours for experiment 


71Y-06.-Continued 




Range 2 


Range 4 


Station 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 


Elevation 
(ft) 


Median 
(mm) 


Median 
(phi) 



375 Hr 



-13 


0.30 


0.34 


1.54 


0.30 


0.29 


1.78 


-11 


0.10 


0.34 


1.56 


0.10 


0.41 


1.28 


-9 


-0.20 


0.27 


1.89 


-0.20 


0.28 


1.85 


-7 


-0.35 


0.27 


1.88 


-0.30 


0.26 


1.93 


-5 


-0.50 


0.26 


1.95 


-0.50 


0.31 


1.71 


-3 


-0.50 


0.26 


1.93 


-0.50 


0.27 


1.88 


-1 


-0.55 


0.27 


1.89 


-0.50 


0.30 


1.75 


1 


-0.59 


0.24 


2.04 


-0.60 


0.30 


1.76 


3 


-0.70 


0.26 


1.96 


-0.60 


0.26 


1.94 


5 


-0.75 


0.28 


1.86 


-0.70 


0.29 


1.77 


7 


-0.70 


0.26 


1.92 


-0.70 


0.26 


1.92 


9 


-0.80 


0.28 


1.82 


-0.70 


0.29 


1.77 


11 


-0.70 


0.25 


2.01 


-0.70 


0.25 


2.02 


13 


-0.70 


0.31 


1.71 


-0.70 


0.31 


1.69 


15 


-0.72 


0.26 


1.96 


-0.72 


0.26 


1.96 


17 


-0.78 


0.30 


1.73 


-0.76 


0.29 


1.80 


19 


-0.85 


0.27 


1.90 


-0.90 


0.26 


1.94 


21 


-1.10 


0.25 


2.01 


-1.18 


0.25 


2.03 


23 


-1.30 


0.28 


1.86 


-1.33 


0.25 


2.00 


25 


-1.60 


0.27 


1.90 


-1.60 


0.26 


1.93 



380 Hr 



-13 
-11 
-9 

-7 

-5 

-3 

-1 

1 

3 

7 

11 

13 

15 

17 

21 

23 

25 



0.30 
0.10 
-0.20 
-0.35 



-0.55 
-0.59 
-0.70 
-0.70 
-0.70 
-0.70 
-0.72 
-0.78 
-1.10 
-1.30 
-1.60 



0.29 
0.25 
0.29 
0.26 



0.30 
0.27 
0.26 
0.26 
0.28 
0.32 
0.29 
0.29 
0.26 
0.26 
0.26 



1.79 
1.99 
1.78 
1.95 



1.72 
1.90 
1.93 
1.95 
1.84 
1.66 
1.81 
1.81 
1.97 
1.93 
1.92 



0.10 
-0.20 
-0.30 
-0.50 
-0.50 
-0.50 
-0.60 



-0.70 
-0.70 

-0.76 
-1.18 
-1.33 
-1.60 



0.28 
0.28 
0.23 
0.29 
0.24 
0.30 
0.26 



0.26 
0.30 

0.29 

0.26 
0.26 



Samples not collected at these stations. 



74 



Table 11. Sediment-size analysis at various hours for experiment 71Y-10. 



Station 



Range 4 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



Range 6 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



24 Hr 



-6 


0.30 


0.26 


1.93 


0.30 


0.26 


1.93 


-4 


0.25 


0.28 


1.86 


0.25 


0.30 


1.74 


-2 


-0.10 


0.28 


1.85 


0.00 


0.34 


1.57 





-0.15 


0.29 


1.77 


-0.20 


0.31 


1.70 


2 


-0.30 


0.30 


1.72 


-0.50 


0.30 


1.74 


4 


-0.40 


0.32 


1.66 


-0.40 


0.30 


1.73 


6 


-0.56 


0.28 


1.85 


-0.55 


0.29 


1.81 


8 


-0.70 


0.26 


1.93 


-0.65 


0.27 


1.88 


10 


-0.90 


0.25 


2.00 


-0.85 


0.26 


1.97 


12 


-1.10 


0.24 


2.06 


-1.00 


0.25 


2.02 



50 Hr 



-6 


0.30 


0.26 


1.95 


0.30 


0.27 


1.91 


-4 


0.20 


0.25 


1.99 


0.20 


0.28 


1.85 


-2 


-0.10 


0.30 


1.72 


-0.20 


0.33 


1.62 





-0.20 


0.32 


1.66 


-0.20 


0.31 


1.69 


2 


-0.20 


0.33 


1.61 


-0.30 


0.30 


1.76 


4 


-0.45 


0.36 


1.47 


-0.40 


0.29 


1.78 


6 


-0.55 


0.26 


1.95 


-0.52 


0.29 


1.79 


8 


-0.70 


0.24 


2.05 


-0.70 


0.30 


1.75 


10 


-0.90 


0.26 


1.97 


-0.81 


0.27 


1.88 


12 


-1.00 


0.25 


2.01 


-1.00 


0.26 


1.96 


14 


-1.20 


0.26 


1.97 


-1.25 


0.25 


2.00 


16 


-1.40 


0.23 


2.15 


-1.45 


0.25 


2.00 


18 


-1.70 


0.24 


2.06 


-1.70 


0.25 


2.00 


20 


-1.95 


0.24 


2.08 


-1.92 


0.25 


2.03 



75 



Table 11. Sediment-size analysis at various hours for experiment 71Y- 10.— Continued 



Station 



Range 4 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



Range 6 



Elevation 
(ft) 



Median 
(mm) 



100 Hr 



-6 


0.30 


0.29 


1.81 


0.30 


0.28 


1.85 


-4 


0.10 


0.26 


1.99 


0.15 


0.28 


1.83 


-2 


-0.10 


0.32 


1.66 


-0.20 


0.33 


1.61 





-0.22 


0.32 


1.66 


-0.24 


0.30 


1.74 


2 


-0.30 


0.32 


1.63 


-0.50 


0.30 


1.76 


4 


-0.45 


0.28 


1.82 


-0.40 


0.31 


1.67 


6 


-0.55 


0.26 


1.93 


-0.58 


0.29 


1.77 


8 


-0.73 


0.26 


1.93 


-0.70 


0.29 


1.80 


10 


-0.85 


0.27 


1.88 


-0.83 


0.28 


1.84 


12 


-1.05 


0.25 


1.98 


-1.00 


0.27 


1.89 


14 


-1.28 


0.26 


1.97 


-1.18 


0.26 


1.96 


16 


-1.60 


0.24 


2.05 


-1.38 


0.25 


1.99 


18 


-1.70 


0.24 


2.05 


-1.60 


0.26 


1.93 


20 


-1.89 


0.25 


2.00 


-1.89 


0.25 


2.01 



200 Hr 



-8 


0.30 


0.30 


1.72 


0.30 


0.37 


1.44 


-6 


0.15 


0.34 


1.56 


0.10 


0.34 


1.56 


-4 


-0.10 


0.37 


1.43 


-0.15 


0.39 


1.37 


-2 


-0.32 


0.34 


1.54 


-0.40 


0.34 


1.54 





-0.51 


0.30 


1.74 


-0.52 


0.31 


1.71 


2 


-0.58 


0.32 


1.63 


-0.70 


0.29 


1.78 


4 


-0.65 


0.28 


1.82 


-0.70 


0.29 


1.81 


6 


-0.70 


0.27 


1.90 


-0.70 


0.30 


1.75 


8 


-0.70 


0.29 


1.78 


-0.70 


0.28 


1.82 


10 


-0.80 


0.29 


1.80 


-0.80 


0.27 


1.88 


12 


-0.80 


0.29 


1.77 


-0.86 


0.28 


1.82 


14 


-1.10 


0.26 


1.93 


-1.00 


0.27 


1.90 


16 


-1.27 


0.26 


1.95 


-1.15 


0.27 


1.91 


18 


-1.45 


0.27 


1.90 


-1.30 


0.26 


1.97 


20 


-1.72 


0.27 


1.91 


-1.50 


0.28 


1.85 


22 


-1.95 


0.26 


1.96 


-1.75 


0.25 


2.01 


24 


-2.10 


0.28 


1.83 


-2.00 


0.26 


1.92 



NOTE.— At 200 hours, one sediment sample was taken on range 8 at station— 4; 
median grain size 0.78 millimeter (0.37 phi). 



76 



Table 11. Sediment-size analysis at various hours for experiment 71 Y-10.— Continued 



Range 4 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



Range 6 



Elevation 
(ft) 



Median 
(mm) 



Median 
(phi) 



300 Hr 



-10 


0.30 


0.41 


1.28 


0.30 


0.29 


1.79 


-8 


0.30 


0.33 


1.58 


0.20 


0.40 


1.34 


-6 


-0.20 


0.47 


1.08 


-0.02 


0.42 


1.26 


-4 


-0.40 


0.34 


1.58 


-0.54 


0.34 


1.57 


-2 


-0.60 


0.34 


1.55 


-0.65 


0.30 


1.72 





-0.80 


0.30 


1.76 


-0.70 


0.35 


1.51 


2 


-0.75 


0.30 


1.73 


-0.66 


0.25 


2.02 


4 


-0.70 


0.23 


2.12 


-0.60 


0.23 


2.13 


6 


-0.65 


0.29 


1.79 


-0.60 


0.31 


1.70 


8 


-0.70 


0.27 


1.91 


-0.70 


0.29 


1.81 


10 


-0.70 


0.29 


1.79 


-0.70 


0.30 


1.74 


12 


-0.75 


0.26 


1.93 


-0.80 


0.27 


1.89 


14 


-0.80 


0.25 


2.01 


-0.83 


0.28 


1.82 


16 


-1.04 


0.25 


2.01 


-1.00 


0.28 


1.83 


18 


-1.22 


0.24 


2.04 


-1.15 


0.27 


1.90 


20 


-1.29 


0.27 


1.89 


-1.25 


0.28 


1.85 


22 


-1.62 


0.28 


1.86 


-1.50 


0.27 


1.91 


24 


-1.94 


0.26 


1.93 


-1.80 


0.25 


2.03 



335 Hr 



-10 


0.30 


0.29 


1.80 


0.30 


0.40 


1.33 


-8 


-0.10 


0.31 


1.70 


0.10 


0.31 


1.67 


-6 


-0.24 


0.35 


1.53 


-0.15 


0.36 


1.46 


-4 


-0.40 


0.37 


1.43 


-0.42 


0.33 


1.62 


-2 


-0.60 


0.29 


1.80 


-0.70 


0.30 


1.73 





-0.80 


0.32 


1.65 


-0.70 


0.30 


1.74 


2 


-0.80 


0.33 


1.60 


-0.70 


0.28 


1.86 


4 


-0.80 


0.26 


1.93 


-0.70 


0.21 


2.26 


6 


-0.80 


0.25 


2.02 


-0.70 


0.25 


1.99 


8 


-0.80 


0.26 


1.95 


-0.70 


0.21 


2.24 


10 


-0.70 


0.31 


1.70 


-0.70 


0.29 


1.79 


12 


-0.75 


0.26 


1.96 


-0.75 


0.26 


1.97 


14 


-0.80 


0.27 


1.88 


-0.80 


0.27 


1.88 


16 


-0.92 


0.27 


1.89 


-0.90 


0.26 


1.95 


18 


-1.12 


0.25 


1.98 


-1.05 


0.25 


2.00 


20 


-1.27 


0.27 


1.90 


-1.18 


0.27 


1.90 


22 


-1.50 


0.26 


1.95 


-1.40 


0.27 


1.92 


24 


-1.78 


0.25 


2.03 


-1.80 


0.26 


1.94 



77 



TaMe 12. Summary of median grain-size values within profile zones for experiments 71Y-06 and 71Y-10. 



Cumulative time 
(hr) 



Profile zones 



Mean 
(nrni) 



Range 
(mm) 



Inshore 



Mean 
(mm) 



Range 
(mm) 



Mean 
(mm) 



Range 
(mm) 



Experiment 71Y-06 



26 


0.31 


0.31 to 0.32 


3 


0.28 


0.27 to 0.30 


9 


0.25 


0.23 to 0.30 


15 


50 


0.30 


0.28 to 0.31 


5 


0.29 


0.28 to 0.30 


8 


0.25 


0.23 to 0.29 


15 


100 


0.29 


0.25 to 0.35 


3 


0.30 


0.28 to 0.31 


9 


0.25 


0.24 to 0.27 


11 


200 


0.29 


0.28 to 0.31 


3 


0.31 


0.29 to 0.34 


10 


0.27 


0.24 to 0.30 


12 


300 


0.36 


0.33 to 0.41 


3 


0.29 


0.27 to 0.34 


22 


0.26 


0.24 to 0.31 


7 


375 


0.38 


0.34 to 0.41 


2 


0.28 


0.24 to 0.31 


28 


0.26 


0.25 to 0.30 


8 


380 


0.27 


0.23 to 0.29 


6 


0.28 


0.24 to 0.32 


15 


0.26 


0.26 


5 


All times (except 380) 


0.32 


0.25 to 0.41 


19 


0.29 


0.24 to 0.34 


86 


0.26 


0.23 to 0.31 


68 



Experiment 71Y-10 



24 


030 


0.28 to 0.34 


5 


0.29 


0.26 to 0.31 


9 


0.25 


0.24 to 0.26 


4 


50 


0.28 


0.25 to 0.30 


3 


0.30 


0.24 to 0.32 


12 


0.25 


0.23 to 0.27 


11 


100 


0.29 


0.26 to 0.32 


3 


0.30 


0.26 to 0.33 


11 


0.26 


0.24 to 0.28 


12 


200 


0.36 


0.34 to 0.39 


4 


0.30 


0.28 to 0.34 


15 


0.27 


0.25 to 0.29 


13 


300 


0.41 


0.29 to 0.41 


2 


0.30 


0.23 to 0.35 


21 


0.27 


0.24 to 0.28 


10 


335 


0.33 


0.29 to 0.40 


3 


0.28 


0.21 to 0.37 


21 


0.26 


0.25 to 0.27 


10 


All times 


0.32 


0.26 to 0.41 


20 


0.29 


0.21 to 0.37 


89 


0.26 


0.24 to 0.29 


60 



Samples collected on the backshore not included. 
NOTE.-The mean of the median sizes at hour was 0.27 millimeter. 



78 



in the mean median size on the foreshore at 300 and 375 hours could have 
been the result of the profile eroding into the relict profile from 1970, 
which had coarser material. The median grain size in the inshore zone 
was 0,2 7 millimeter or greater for the first 300 hours and at 375 hours 
a few samples had a djg lower than 0.27 millimeter; the median grain 
size in the offshore zone was as low as 0o23 millimeter. As expected, 
more of the finer material eroded from the foreshore (raising the dso 
in that zone) and deposited in the offshore (lowering the d^Q in that 
zone) . The material deposited on the foreshore by the long-period wave 
was finer material, thus significantly lowering the dso on the fore- 
shore at 380 hours. 

b. Experiment 71Y-10 . A similar summary of median grain-size data 
for experiment 71Y-10 is given in Table 12. The same trend in median 
grain-size changes occurred, but was even more distinct. With one ex- 
ception, the median grain size in the foreshore zone remained above 0.27 
millimeter. The increase in the mean median size in the foreshore zone 
could have been the erosion into the relict profile. In the offshore, 
dso varied only between 0,24 and 0.29 millimeter. 

4. Breaker Characteristics . 

a. Experiment 71Y-06 . Breaker position superimposed on contour move- 
ment along range 3 is shown in Figure 37 for experiment 71Y-06. During 
the first 180 hours the wave broke mostly at a depth of 0.6 foot, breaking 
by plunging for the first 105 hours and by plunging and spilling for the 
next 75 hours. After 180 hours the breaker position coincided with the 
general seaward movement of the -0.7- foot contour, and the breaker type 
was primarily spilling. Between 220 and 315 hours the wave broke twice-- 
by spilling at a depth of 0.7 foot and by plunging at the toe of the fore- 
shore. 

Between 375 and 380 hours the 3. 75-second wave was a surging-type 
breaker on the foreshore. 

b. Experiment 71Y-10 . Breaker position superimposed on contour move- 
ment along range 5 is shown in Figure 38 for experiment 71Y-10. The wave 
broke by plunging at a depth of 0.6 foot for the first 125 hours with no 
lateral variation in the breaker position. From 125 to 265 hours the wave 
type varied between plunging and spilling, and the breaker position varied 
from stations 8 to 10 along range 9 (breaker depth about 0.7 foot), and 
from stations 5 to 7 along range 1 (breaker depth about 0.6 foot). 

From 265 to 280 hours the breaker type was spilling and the breaker 
position along range 9 remained at about station 9. Along range 1, the 
breaker position moved to station +2 at 270 hours and -2 at 275 and 280 
hours . 

The most significant change occurred between 280 and 285 hours. Be- 
tween range 10 (station 8) and range 3 (station 2) the wave broke by spill- 
ing; between range 3 and range the wave broke by plunging at station -2 



79 




150 200 
Time (hr) 



Figure 37. Movement of breaker position in experiment 71Y-06, 



80 



-lOr 



Breoker Position 



0.2 Ft. 
0.0 Ft. 

0.3 Ft. 
0.6 Ft. o 




50 



100 



150 200 250 

Time (tir) 



300 



350 



400 



Figure 38. Movement of breaker position in experiment 71Y-10, 



(Fig. 39) . This pattern was maintained for the remainder of the experi- 
ment. During the last 10 hours of this experiment, a strong seaward 
current was observed in the inshore zone between ranges and 2, in the 
region where the wave did not break until reaching the toe of the fore- 
shore. 

Contour maps in Figure 40 show the profile at 135 and 335 hours. 
Figure 41 shows ripple formations between ranges and 2 and stations 
+2 to +5, where large ripples are oriented in the seaward direction. A 
plausible explanation for the breaking pattern and current development 
is that: (a) As the wave broke first along range 9, energy moved along 
the wave crest toward this range; (b) this loss of energy along the lower 
ranges decreased the wave height along the lower ranges causing the waves 
to break even farther inshore so that eventually the waves along range 2 
lost enough height (energy) to not break until the waves had traveled 
farther up the profile; and (c) the flow of energy along the wave crest 
toward range 9 increased the shoreward mass transport along that side of 
the tank, and the seaward return flow of mass transport chose the path 
of least resistance--along range 1. 

5. Water Temperature . 

Figure 42 gives data on daily average water temperature versus both 
cumulative test time and dates for experiments 71Y-06 and 71Y-10. 

III. PROFILE DEVELOPMENT AND REFLECTIVITY 

Results are analyzed by: (a) Profile development, in which the inter- 
dependence of the changes in the profile shape, sediment-size distribu- 
tion, breaker characteristics, and water temperature is analyzed; and 
(b) profile reflectivity, in which changes in profile shape and breaker 
characteristics are related to the variability of the reflection coeffi- 
cient. Profile development is discussed first to provide an introduction 
to profile reflectivity. 

1. Profile Development . 

a. Experiment 71Y-06 . The important changes in the foreshore, in- 
shore, and offshore zones, the breaker conditions, median grain size, and 
water temperature during experiment 71Y-06 are summarized and tabulated 
as a function of time in Table 13. 

During the first hour the foreshore zone developed the basic shape 
which was maintained throughout the remainder of the experiment, and a 
longshore bar was formed by the plunging breaker in the inner inshore 
region. The eroded material during this early development was deposited 
at elevations -0.6 to -1.2 feet in the first 2 hours. As the foreshore 
retreated at 0.113 foot (3.44 centimeters) per hour for the first 15 hours 
and the bar moved shoreward at 0.018 foot per hour, the eroded material 
was deposited mostly at elevation -0„9 to -1„2 feet up to 10 hours and 
uniformly at all depths in the offshore zone after 10 hours (see Figs. 7, 
8, and 9). After 15 hours the shoreline recession rate dropped to 0.025 
foot per hour. 

82 




83 



-5 



_ 



10 



15 



20 



25 



C^° 





0.2 
0.1 
0.0 
■0.1 



-0.2 

-0.3 
-0.4 
-0.5 

-0.6 



•0.7 
08 



-0.9 

- 1.0 

- I.I 

- 1.2 

- 1.3 

- 1.4 

- 1.5 

- 1.6 

- 1.7 

- 1.8 

- 1.9 
-2.0 
-2.1 



-lOi- 



-5 



o 

e 



15 



20 



25 




-0.80 



0.2 
0.1 
0.0 
-0 1 
-0.2 
-0.3 
-0.4 

-0.5 



■0.6 



-0.7 



■0.8 
■0.9 
■1.0 



■I.I 
■1.2 
■1.3 
■ 1.4 
■1.5 
■1.6 
■1.7 
■1.8 

■1.9 
■2.0 
-2.1 



a. I35hr b. 335hr 

Figure 40. Contour maps of experiment 71Y-10 at 135 and 335 hours 



84 



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50 100 150 200 250 

Cumulative Time [\\\\ 



300 350 



400 



7-. 30 




50 



100 150 200 250 300 350 400 
Cumulative Time (hr) 



Figure 42. Water temperature data from experiments 71Y-06 and 71Y-10, 



86 



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87 



At 105 hours the breaker type became mixed between plunging and spill- 
ing, indicating that the flatter slope in the offshore had begun to affect 
the waves. At 175 hours, erosion at elevation -0.6 foot and deposition at 
-0.7 and -0.8 foot caused the breaker at 180 hours to become consistently 
spilling and to move seaward with the -0.7-foot contour. After 200 hours, 
with the wave no longer breaking near the bar, the bar eroded and a shelf 
developed (erosion at -0o5 and -0.6 foot, and deposition at -0o7 and -0.8 
foot; see Fig. 37). Deposition mostly at elevations -0.9 to -1.3 feet in 
the offshore zone steepened the offshore slope and caused a farther sea- 
ward extension of the inshore zone (Figs. 7, 8, and 9). 

From 220 to 315 hours the wave broke a second time (in the inner in- 
shore) , further eroding and steepening that region. Continuous erosion 
of the foreshore and inner inshore, and deposition in the offshore caused 
the flat shelf in the outer inshore to grow in both directions (Fig. 37). 

More finer material eroded from the foreshore and inner inshore zones 
leaving the sediment-size distribution coarser in those areas and decreas- 
ing the median grain size in the offshore zone where it was deposited 
(Table 12). 

The daily mean water temperature with shoreline position is compared 
in Figure 43. For the first 15 hours the shoreline recession rate was 
0.113 foot per hour; after 15 hours the shoreline recession rate was an 
average 0.025 foot per hour. Because the backshore slope was 0.10 and 
not flat, the volume rate of erosion was continually increasing. The 
water temperature was increasing for the first 25 hours and then fairly 
high and constant until 200 hours. From 200 hours to 345 hours the 
temperature gradually dropped; from 345 to 365 hours the temperature 
dropped sharply. The drops in temperature, particularly the sharp drop, 
were not accompanied by an increase in the shoreline recession rate. 

b. Experiment 71Y-10 . The major events of the profile development 
in experiment 71Y-10 are summarized in Table 14. During the first hour 
the foreshore developed a characteristic shape, and a longshore bar was 
formed in the inner inshore by the plunging breaker. This material was 
deposited at depths of 0.6 to 1.4 feet. As the shoreline retreated at 
a rate of 0.133 foot (4.05 centimeters) per hour (for the first 15 hours), 
the eroded material was deposited along all ranges at depths from 0.6 to 
1.4 feet until 5 hours, and along all ranges at depths from 0.9 to 1.4 
feet until 10 hours (Figs. 10 to 14)-. 

After 10 hours the lateral variations became significant. The ero- 
sion rate dropped to 0.016 foot per hour after 15 hours. For an unknown 
reason, all the material was deposited in the offshore zone along the 
range 9 side of the tank, while the erosion from the foreshore and inner 
inshore was uniform across the tank. This situation continued for 100 
hours when the offshore along the center of the tank (range 5) began to 
prograde at the same rate. However, by this time the offshore zone along 
range 9 was already 2 feet farther offshore (Fig. 31). 



88 



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At 115 hours along range 9 the bar in the inner inshore began to erode 
and a flat shelf began to develop. This pattern continued progressively 
across the tank: progradation of the offshore zone, erosion of the long- 
shore bar, and development of the flat shelf in the outer inshore region. 

With the profile along range 9 closer to the generator, the waves began 
to refract and break first along the range 9 side of the tank, draining 
energy along the wave crests toward range 9 (see Fig. 41, a at 135 hours). 

Deposition in the offshore along range 1 began at 170 hours. Erosion 
of the bar and development of the shelf were completed by 215 hours. Depo- 
sition in the offshore zone along the other ranges continued, thus main- 
taining the refraction pattern and the skewed breaker position. By 265 
hours the refraction had decreased the wave energy (and wave height) 
along range 1 so that the breaker position was even farther inshore at 
a shallower depth where the smaller wave would break. At 280 hours the 
waves along range 1 did not break as part of the continuous breaker line 
between ranges and 2, but broke separately at the base of the foreshore 
(Fig. 39). The refraction increased the mass transport along the range 9 
side and the return flow was concentrated along range 1 where the incident 
wave energy was least. 

The concentration of energy along range 9 due to refraction also 
accounts for the increased shoreline recession along the range. The 
increased shoreline recession along range 1 may have been the result of 
the wave breaking closer to the foreshore, thereby increasing the tur- 
bulence at the foreshore (Fig. 18) . 

Water temperature and shoreline position for experiment 71Y-10 are 
compared in Figure 43. For the first 15 hours the shoreline recession 
rate was 0.133 foot per hour; from 15 to 205 hours the rate was 0.016 
foot per hour. At 205 to 335 hours the shoreline recession rate varied 
across the tank, from 0.016 foot per hour along the center to 0.025 foot 
per hour along the outside ranges of the tank. The water ten^ierature rose 
sharply during the first 2 hours and then remained fairly high and constant 
until 125 hours. The temperature dropped gradually between 125 and 280 
hours, then dropped sharply between 280 and 300 hours. The increase in 
the recession rate along the outside ranges occurred during a period when 
the temperature was gradually dropping, but the sharp drop in temperature 
at 280 hours was not accompanied by an increase in recession rate. 

c. Comparison of the Two Experiments . The general shape of the pro- 
files and the sequence of events during the development of the profiles 
appeared to be similar in the two experiments, and neither experiment 
reached equilibriiom. Significant lateral variations in the rate of pro- 
file development, which occurred in the wider tank, did not occur in the 
narrower tank. 

(1) Shoreline Recession Rate . In experiment 71Y-06 the shoreline 
retreated at a uniform (across the tank) rate of 0.025 foot per hour after 
15 hours. In experiment 71Y-10 the shoreline recession rate was lower 
(0.016 foot per hour) and more uniform across the tank between 15 and 205 



hours. After 205 hours in experiment 71Y-10 the recession rate increased 
to 0.025 foot per hour along the sides of the 10-foot tank while remain- 
ing at 0.016 foot per hour in the center. Figure 44 compares the shore- 
line movement along the center ranges of the two tanks and shows that the 
erosion rate was slightly greater in the 6- foot tank. 

(2) Inshore and Offshore Zones . In both experiments along a 
given range, the sequence of events in profile development was the same: 
development of a longshore bar, deposition in the offshore zone, seaward 
movement of the breaker, erosion of the bar, and development of the shelf. 
In the narrower tank, this development occurred along all ranges almost 
simultaneously; in the wider tank, it occurred first along range 9 and 
then progressed slowly across the tank. This unusual development caused 
significant lateral variations in breaker depth, breaker type, and lit- 
toral currents. The slower development is further amplified by the fact 
that the center range in the 6-foot tank (solid line in Fig. 44) was rep- 
resentative of all three ranges; whereas, the dashline in Figure 44 was 
the mean value of contour position in the 10-foot tank and this mean was 
more representative of changes along range 1 where the development was 
slower than the mean, 

2. Profile Reflectivity . 

The basic profile shapes which evolved during the profile development 
are shown in Figure 6. Early profiles (solid line in Fig. 6) had a steep 
foreshore, a short inshore with a longshore bar formed by the plunging 
breaker, and a gently sloping offshore zone. Later profiles (dashline in 
Fig. 6) also had a steep foreshore, but the inshore widened to a long, 
flat shelf which terminated in a relatively steep offshore zone. 

Chesnutt and Galvin (1974) discussed the processes which reflect wave 
energy from movable beds in these experiments. The processes include the 
conversion of potential energy stored in runup on the foreshore into a 
seaward-traveling wave, the seaward radiation of energy from a plunging 
breaker, and reflection of the incident wave from the movable bed, par- 
ticularly where the depth over the movable bed changes significantly. 
Depth changes are significant if the depth difference is an appreciable 
fraction of the average depth over a horizontal distance less than a 
wavelength. For conditions of these experiments, the wavelength is 14.3 
feet (4.36 meters) in the section seaward of the movable bed and approxi- 
mately 9 feet (2.74 meters) over the inshore zone. 

a. Reflection From the Foreshore . The foreshore zone developed 
within the first hour of testing, well before the other elements of the 
movable-bed profile had become prominent. The developed foreshore had a 
slope of about 0.20, considerably steeper than the original 0.10 slope. 
The initial high values of K^ are probably the result of reflection 
from the foreshore of waves which dissipated little energy until almost 
at the foreshore. Reflection from the foreshore is a function of the 
height of the wave reaching the foreshore, and this height would diminish 
due to increased bottom friction as the inshore and offshore segments of 
the profile (Fig. 6) became prominent. 



92 



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93 



b. Reflection as a Result of Wave Breaking . On the concrete slab 
the wave broke as a plunging breaker and on the movable-bed profile, the 
wave was initially a less well-developed plunger and evolved to a spill- 
ing breaker. The reflection from the concrete slab was an average 0.12 
for both experiments, where the plionger is assumed to contribute more 
significantly to the total reflection. The lowest values of reflection 
in the movable-bed tanks were slightly lower than the K„ for the fixed 
bed and occurred during the period when the wave broke by plunging. The 
reflection from the spilling breaker later in the experiments is assumed 
to be negligible. 

c. Effect of Inshore and Offshore . As the experiments proceeded, 
the inshore widened and flattened and the offshore steepened. At first, 
the widening of the inshore dominated; the lowering of the reflection 
after the high initial values (Figs. 2 and 3) is attributed to the 
greater energy dissipation in the inshore. The later steepening of the 
offshore correlates well with the trend toward higher K^ later in the 
experiments (compare the offshore contour positions in Figs. 8 and 12 
with the appropriate reflection values in Figs. 2 and 3). 

With the development of the two reflecting zones (foreshore and off- 
shore) separated by a relatively flat inshore zone, the measured reflected 
wave was composed of two reflected waves. A change in phase or amplitude 
of either reflected wave would change the phase and amplitude of the 
measured wave. Part of the long-term K^ variability can be attributed 
to the change in phase difference between these two reflected waves as 
the foreshore retreated landward and the offshore built seaward. 

Chesnutt and Galvin (1974) examined results from experiment 71Y-06 
and pointed out an apparent correlation between the movement of the -0.7- 
foot contour and the variability of the reflection coefficient, and sug- 
gested that the reflection is very sensitive to small changes in the depth 
near the seaward edge of the inshore zone. These depth changes would 
cause variability in the reflection of the incident wave from the offshore 
slope and variability in the amount of energy trapped on the inshore shelf. 

The position of the -0.7- foot contour and the reflection coefficient 
versus time for the two experiments are compared in Figure 45. The sea- 
ward (downward) movement of the -0.7- foot contour in the figure is an 
indication of the development of the steeper offshore slope. Both ex- 
periments show a general increase in the reflection coefficient as the 
-0.7- foot contour moved seaward (and the offshore slope increased). 

In experiment 71Y-06, the K^ values are highest at 320, 360, and 
375 hours when the -0.7- foot contour is at the seawardmost position; the 
K^ values are low at 225 and 335 hours when 4:he -0.7- foot contour is at 
the landwardmost position. The same relationship exists at other times 
(275, 290, and 300 hours), but the variation is not as great. A scatter 
plot (Fig. 46) of K^ versus position of the seawardmost -0.7- foot con- 
tour for all times after 220 hours indicate the correlation. 



94 



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Range 03 

Range 05 




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Experiment 7IY-06 



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150 200 250 

Cumulative Time ( hr ) 



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Range 05 
Range 09 




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Cumulative Time ( hr) 



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Figure 45. Comparison of the -0.7-foot contour position and Kn in experiments 
71Y-06 and 71Y-10. 



95 



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Position of Seawardmost -0.7 Contour (ft) 

Figure 46. Correlation of the -0.7-foot contour position and K^ in 
experiment 71Y-06. 



96 



In experiment 71Y-10 the -Oo 7-foot contour varied in position, but not 
uniformly across the tank. The K^ in this experiment did not fluctuate 
in response to any particular contour movements; however, with the com- 
plex profile development, a lack of correlation is expected. These lateral 
variations in profile development certainly contributed to a complex wave 
reflection pattern, which appeared simple and less variable when only re- 
corded along the center of the tank. 

IV. DISCUSSION OF RESULTS 

1. Wave Height Variability . 

Three probable causes of wave height variability in the two experi- 
ments are: (a) Wave reflection from the changing profile, (b) re- 
reflection from the wave generator, and (c) secondary waves. These 
experiments were designed primarily to quantify the amount of variability 
due to reflection. 

a. Wave Reflection From the Profile . The Kj? in the fixed-bed tanks 
increased during the early hours of the experiments and decreased in the 
later hours. In the narrower fixed-bed tank, the K^ was always higher. 
The K/? in the movable-bed tanks varied from 0.08 to 0.30 in experiment 
71Y-06 and from 0.03 to 0.18 in experiment 71Y-10 (Figs. 2 and 3). K^ 
values during the development of the foreshore were relatively high, then 
decreased as the remainder of the profile began to adjust. Later, after 
the profile had developed a relatively steep offshore slope, the K^ in- 
creased and the variation in Kj^ increased. The variations appear to 
have been caused by small changes in depth near the seaward edge of the 
inshore zone (the top of the offshore reflecting surface) and by the 
gradual separation of the two reflecting surfaces as the offshore slope 
prograded seaward (see Fig. 45, and Chesnutt and Galvin, 1974). 

b. Re-Reflection From the Generator . The reflected wave advanced to 
the generator and was reflected. As the height of the reflected wave 
varied, the height of the re-reflected wave varied; as the phase differ- 
ence between the reflected wave and the generator motion varied with 
changes in the profile, the height and phase of the re-reflected wave 
varied. The height of the wave incident to the profile, which was the 
average of wave heights along the full tank length and was composed of 
the generated wave and the re-reflected wave, varied from 0.32 to 0.41 
foot (9.8 to 12.5 centimeters) in experiments 71Y-06 and 71Y-10 (Tables 

6 and 7). Part of that variation (0.04 foot in experiment 71Y-06 and 
0.03 foot in experiment 71Y-10) could be attributed to measurement errors, 
variations in the generated wave, and all other errors not caused by a 
changing profile. The remainder of the variation (0.05 and 0.06 foot) is 
likely due to varying re-reflection. 

c. Secondary Waves . Along the length of the tank, between the gener- 
ator and the toe of the profile, wave heights on a given recording varied 
as the result of secondary waves. Galvin (1972) and Hulsbergen (1974) 



97 



described secondary waves (called salitons by Galvin) and their effects. 
Although secondary waves were observed on the wave records, these waves 
were not analyzed in this study; wave height variations due to secondary 
waves did not affect the wave height data presented here. 

2. Profile Eqmlibrium . 

The experiments were extended over several hundred hours in hopes of 
defining the equilibrium profile for the given wave and sediment condi- 
tions. At the end, there was no indication that either experiment was 
close to equilibrium (see Figs. 7 to 14). In experiment 71Y-10 the 
profile had great lateral variation, which seemed to be getting con- 
tinually more complex. 

The decreasing water temperature at the end of the experiments, 
increasing the viscosity and presumably the sediment-carrying capacity 
(Chesnutt, 1975; Chesnutt and Stafford, 1977), may have contributed to 
the continuing erosion and lack of equilibrium. However, the lack of 
an increase in recession rate at the times of the sharpest temperature 
drop seems to discount this explanation. The continually changing dis- 
tances between the wave generator and parts of the profile (foreshore and 
offshore) causing variations in re-reflection and secondary waves may 
also have prevented the profile from reaching equilibrium. 

To further complicate the question of profile eqmlibrium, Collins 
and Chesnutt (1975, 19 76) showed that, even with constant water tempera- 
ture, the final, unchanging profile for the same wave and sediment condi- 
tions was not always repeatable. 

A constant rate of volume erosion might be an acceptable alternative 
to profile equilibrium for defining steady-state conditions in some 
coastal engineering experiments, but that may also be affected by water 
temperature and other variables. 

3. Other Laboratory Effects . 

The differences in test conditions (tank width, initial test length, 
and the loncont rolled water temperature) provide possible explanations 
for the differences in rate of profile development discussed in Section 
III,l,c, but also prevent a rigorous proof of the effect of any one of 
these differences as definite causes. Chesnutt (1975) discussed the 
effects of initial test length and water temperature. 

a. Water Temperature . The water temperature varied from 29° to 1° 
Celsius for the experiments which began in May and June and continued 
into early December. The dynamic viscosity varied from 1.7 x 10"^ to 
3.0 X 10-5 pounds-second per square foot (7.98 x 10-3 ^g 14. 30 x lO'^ 
grams-second per square centimeter). The existence of a temperature 
effect seems to be disproven by the data presented in this study. How- 
ever, the possibility of a temperature effect prevents the drawing of 
strong conclusions about, profile equilibrium and other laboratory effects, 

98 



b. Initial Test Length . Two possible phenomena are affected by 
varying tank length, re-reflection and secondary waves. Chesnutt (1975) 
and Chesnutt and Stafford (1977) discussed these phenomena and the possi- 
ble effects on the rate of profile development. 

c. Tank Width . Experiments 71Y-06 and 71Y-10 probably serve their 
greatest purpose by pointing out the effect of tank width. This study 
(Sec. 111,1) discussed the significant lateral variations in the wider 
tank, which must have resulted from a minor perturbation in profile de- 
velopment. Lateral variations in profile shape occur on natural beaches, 
and variations on a wide laboratory beach would not be unexpected. In 
the 6-foot tank, the profile was essentially two-dimensional; in the 10- 
foot tank, the natural lateral variations were most likely distorted by 
the tank walls. 

V. CONCLUSIONS AND RECOMMENDATIONS 

1. Conclusions . 

(a) In two experiments with a water depth of 2.33 feet (0.71 meter) 
a wave period of 1.90 seconds, and a generator stroke of 0.39 foot (11.9 
centimeters), the average incident wave height was 0.38 foot (11.3 centi- 
meters) in experiment 71Y-06 and 0.36 foot in experiment 71Y-10. Reflec- 
tion measurements in the control tanks with a fixed-bed profile varied 
from 0.10 to 0.16 in experiment 71Y-06 and from 0.09 to 0.12 in experi- 
ment 71Y-10, indicating that the wave generators were operating uniformly 
and that the error in determining reflection from the changing profile 
was about ±0,03 for experiment 71Y-06 and ±0.015 in experiment 71Y-10. 
The lower K^ in the wider tank is probably due to an unknown width 
effect (Tables 6 and 8). 

(b) Kji varied from 0.08 to 0.30 in experiment 71Y-06 and from 0.03 
to 0.16 in experiment 71Y-10. The variation in K^ correlates with pro- 
file changes. K^ was high during the development of the foreshore and 
decreased as the inshore widened. Later increases in Kj^ occurred when 
the offshore slope steepened. Large fluctuations in Kj^ occurred at 
times of large shifts in contour position on the flat inshore zone, sug- 
gesting that reflection is quite sensitive to small changes in depth at 
the shoreward edge of the submerged reflecting surface (Figs. 3, 4, 45, 
and 46) . 

(c) Profiles along given ranges in the two experiments developed in 
the same sequence, but did not reach equilibrium. In the wider tank, the 
development of the flat shelf in the inshore zone began along one side of 
the tank and the development progressed slowly across the tank, causing 
significant differences in breaker type and depth across the tank and a 
strong seaward current along one side of the tanko This development 
suggests that tank width can significantly affect laboratory studies of 
coastal processes (Figs. 7 to 14). 



99 



(d) The shoreline recession rate was a constant 0.025 foot per hour 
uniformly across the tank after 15 hours in experiment 71Y-06. In experi- 
ment 71Y-10, the shoreline recession rate was a constant, uniform 0.016 
foot per hour between 15 and 205 hours; for the last 130 hours, the rate 
along the outside ranges of the tank increased to 0.025 foot per hour 
(Fig. 18). 

(e) The slower development of the inshore shelf across the full width 
of the tank and slightly slower shoreline recession rate in the wider tank 
indicate that even wider beaches (closer to an infinitely long beach) 
would develop more slowly. Until tank width effects can be quantified, 
engineers should be careful in extrapolating shoreline recession rates 
from two-dimensional laboratory tests to field problems (Fig. 44). 

(f) Changes in the sediment-size distribution along a laboratory 
profile appear to be measurable, even for fine, well-sorted sand. The 
median size along the initial profile was 0.27 millimeter. At the end 
of the experiments the mean median was 0.32 millimeter in the foreshore 
zone, 0.29 millimeter in the inshore zone, and 0.26 millimeter in the 
offshore zone (Tables 10 and 11) . (Sand sizes are RSA values which tend 
to average 0.04 millimeter higher than sieve analyses of the same sample.) 

(g) The long, low wave run near the end of experiment 71Y-06 on the 
steep wave profile quickly began the natural healing process of the beach, 
which occurs after storms in nature (Figs. 33, 34, and 35). 

2. Recommendations . 

(a) Becaiise of varying reflectivity of the profiles, incident wave 
measurements to characterize a three-dimensional coastal engineering 
experiment should be based on calibration of the wave generator rather 
than isolated wave measurements during the experiment. 

(b) Experimenters should be cautious in defining equilibrium profile 
conditions and should consider the possibility of using other means for 
characterizing steady-state conditions in coastal processes experiments 
and models. 

(c) In conducting two-dimensional studies of profile development, 
the tank width should not be too gre^t, probably less than half the 
incident wavelength. But extrapolation of narrow tank results should 
assume variability in profile development in the longshore direction. 

3. Further Analysis . 

These experiments were essentially the same as the experiments dis- 
cussed in Volume II except for the 7- foot difference in initial test 
length. These results will be compared with results from Volume II in 
Volume VIII. 



100 



LITERATURE CITED 

ALLEN, R.H., "A Glossary of Coastal Engineering Terms," MP 2-72, U.S. 
Army, Corps of Engineers, Coastal Engineering Research Center, 
Washington, D.C., Apr. 1972. 

CHESNUTT, C.B., "Laboratory Effects in Coastal Movable-Bed Models," 

Prooeedings of the Symposium on Modeling Techniques, 1975, pp. 945-961. 

CHESNUTT, C.B., and LEFFLER, M.W., "Reduced Data from the Laboratory 
Effects in Beach Studies (LEBS) Experiments 71Y-07 and 71Y-10," 
Laboratory Memorandum No. 2, U.S. Army, Corps of Engineers, Coastal 
Engineering Research Center, Fort Belvoir, Va. , unpublished, Oct. 1977. 

CHESNUTT, C.B., and GALVIN, C.J., Jr., "Lab Profile and Reflection Changes 
for Hq/Lq = 0.02," Proceedings of the 14th Conference on Coastal Engi- 
neering^ 1974, pp. 958-977. 

CHESNUTT, C.B., and STAFFORD, R.P., "Movable-Bed Experiments with Hq/Lq = 
0.021 (1970)," Vol. II, MR 77-7, Laboratory Effects in Beach Studies, 
U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 
Fort Belvoir, Va., Aug. 1977. 

CHESNUTT, C.B., et al., "Beach Profile Development on an Initial 1:10 
Slope of 0.2 millimeter Sand," Transactions of the American Geophysical 
Union, Vol. 53, 1972, p. 411. 

COLLINS, J.I., and CHESNUTT, C.B., "Tests on the Equilibrium Profiles of 
Model Beaches and the Effects of Grain Shape and Size Distribution," 

Prooeedings of the Symposium on Modeling Techniques , 1975, pp. 907-926. 

COLLINS, J.I., and CHESNUTT, C.B., "Grain Shape and Size Distribution 
Effects in Coastal Models," TP 76-11, U.S. Army, Corps of Engineers, 
Coastal Engineering Research Center, Fort Belvoir, Va., July 1976. 

FAIRCHILD, J.C, "Laboratory Tests of Longshore Transport," Proceedings 
of the 12th Conference on Coastal Engineering, 1970a, pp. 867-889. 

FAIRCHILD, J.C, "Wave Diffraction in a Laboratory Movable-Bed Set-up," 
Bulletin and Summary of Research Progress Fiscal Years 1967-69 , Vol. 
Ill, U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 
Washington, D.C., 1970b, pp. 29-40. 

GALVIN, C.J., Jr., "Finite-Amplitude, Shallow Water -Waves of Periodically 
Recurring form," Proceedings of the Sumposium on long Waves, 1972, 
pp. 1-32. 

HULSBERGEN, C.H., "Origin, Effect, and Suppression of Secondary Waves," 

Proceedings of the 14th Conference en Coastal Engineering , 1974, pp. 
392-411. 



101 



SAVAGE, R.P., "Laboratory Study of the Effect of Groins on the Rate of 
Littoral Transport: Equipment Development and Initial Tests," TM-114, 
U.S. Army, Corps of Engineers, Beach Erosion Board, Washington, D.C. , 
June 1959. 

SAVAGE, R.P., "Laboratory Determination of Littoral-Transport Rates," 

Joiamal of the Waterways and Harbors Division, Vol. 88, No. WW2, May 
1962, pp. 69-92. 

STAFFORD, R.P., and CHESNUTT, C.B., "Procedures Used in 10 Movable-Bed 
Experiments," Vol. 1, MR 77-7, Laboratory Effects in Beach Studies, 
U.S. Army, Corps of Engineers, Coastal Engineering Research Center, 
Fort Belvoir, Va. , June 1977. 

U.S. ARMY, CORPS OF ENGINEERS, COASTAL ENGINEERING RESEARCH CENTER, Shore 
Protection Manual , Vols. I, II, and III, 2d ed. , Stock No. 008-022- 
00077-1, U.S. Government Printing Office, Washington, D.C, 1975, 1,160 
pp. 



102 



APPENDIX 

EXPERII-ffiNTAL PROCEDURES FOR 71Y-06 and 71Y-10 

This appendix docioments those aspects of the experimental procedures 
unique to experiments 71Y-06 and 71Y-10. The procedures common to all 
experiments are documented in Volume I (Stafford and Chesnutt, 1977). 

1. Experimental Layout . 

At the beginning of the 1971 experiments, the movable-bed profiles 
were constructed with sufficient sand to move the initial SWL intercept 
7 feet closer to the generator. Because the initial SWL intercept on the 
movable bed is the standard reference point, the tapes along the center 
of each pair of tanks were moved to establish the new origin 7 feet 
seaward of the origin used in experiments 70Y-06 and 70-10 (Chesnutt and 
Stafford, 1977) . This resulted in a 7-foot offset of the origin in the 
fixed-bed tanks. Figure A-1 shows the position of the initial profiles 
within each pair of tanks and the adjusted x-axis. 

2. Data Collection , 
a. Regular Data . 

(1) Wave Height Variability . During the first 10-minute run of 
each experiment and from 375 to 375:10 hours in experiment 71Y-06, a con- 
tinuous water surface elevation was recorded at station 25 near the toe 
of the movable-bed slope (Fig. A-1). Wave envelopes in all subsequent 
runs were recorded with wave gages moving toward and away from the gen- 
erators along the center of each tank from station +15 to +85 in experi- 
ment 71Y-06 and +15 to +50 in experiment 71Y-10 with the instrument 
carriage moving at a near-constant speed of 10 feet per minute. Wave 
records 002 to 006 from experiment 71Y-06 contain only one envelope because 
the runs were too short to permit recording of two envelopes. 

(2) Breakers . Table 3 indicates the times during runs when 
breaker data were collected, which included taking 35-millimeter slides 

of the breakers three times during each run, recording the breaker position 
in the logbook just before the end of each run, and preparing the visual 
observation form near the end of each run. The first two procedures were 
used throughout the two experiments and the use of the visual observation 
form was initiated 18 August 1971, at 78 hours in experiment 71Y-10 and 
140 hours in experiment 71Y-06. 

Unlike the two experiments in 1970, the carriage and camera locations 
were not maintained at the same positions throughout the tests; therefore, 
the slides were not useful for determining breaker position. Since the 
breaker station recorded in the logbook was the position along the center- 
line of the tank, lateral variations in breaker positions were not recorded. 
The visual observation form was used to sketch the breaker position 



103 



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J0tDJ3U99 
9ADM 



104 



and type, allowing technicians to record lateral variations in breaker 
position, and the positions of profile features, such as the shoreline 
and the scarp on a plan view drawing of the wave tank. 

b. Special Data . Three types of special data were collected at 
less frequent intervals, and Table A-1 indicates the times when each 
type of data was collected. 

3. Data Reduction . 

a. Wave Height Variability . All wave reflection data collected from 
the movable-bed profiles in the two experiments were reduced by both the 
manual and automated methods. Table A-2 presents the K/^ data determined 
by the automated method. Plots of K/^ versus time (Figs. A-2 and A-3) 
compare results from the two methods for experiments 71Y-06 and 71Y-10. 
Figures A-4 and A-5 are plots of manual K;^ values versus automated K^ 
values. These plots show that the automated method gave consistently 
lower results and that the difference is not a function of the magnitude 
of K/?. 

b. Sand-Size Distribution Data . All samples were analyzed in the 
CERC Petrology Laboratory using the RSA. Approximately 5 percent of the 
samples were analyzed by project personnel using the dry sieve method as 
a quality control measure. 

c. Breaker Data . Breaker type was determined from slides and, after 
84 hours in experiment 71Y-10 and 140 hours in experiment 71Y-06, from 
the visual observation forms. Breaker position data were determined from 
the logbooks and the visual observation forms. 



105 



Table A-1. Summary of special data collection. 


Time (hr) 


Limits (It) 


Profile survey' 


Photo survey 


Sand sample^ 


Experiment 71Y-06 







Not taken 


Not taken 


-6 to +22 


26 


Not taken 


-7 to +23 


-6 to +24 


52 


-6.5 to +19.0 


-7 to +23 


-5 to +23 


100 


-6.5 to +19.0 


-7 to +25 


-7 to +19 


200 


-5.0 to +20.0 


-9 to +25 


-9 to +21 


300 


-11.0 to +21.0 


-13 to +31 


-9 to +21 


375 


-13.5 to +21.0 


-14 to +31 


-13 to +25 


380 


-13.5 to +21.0 


-14 to +31 


-13 to +25 




Experime 


nt 71Y-10 







Not taken 


Not taken 


Not taken 


24 


-6.5 to +12.0 


-7 to +26 


-6 to +20 


50 


-6.5 to +14.5 


-7 to +26 


-6 to +20 


100 


-6.5 to +14.5 


-7 to +26 


-6 to +20 


200 


-7.5 to +20.0 


-10 to +29 


-8 to +24 


300 


-10.5 to +21.0 


-13 to +29 


-8 to +24 


335 


-10.5 to +21.0 


-13 to +29 


-10 to +24 



'Elevation measurements at 0.5-foot intervals between the given 
stations along ranges 0.5 foot apart. 

^Samples collected at 2-foot intervals between given limits along 
ranges 1 foot either side of centerline. 



106 



Table A-2. Reflection coefficients by automated method for experiments 71Y-06 and 71Y-10. 



Movable bed Fixed bed 



Experiment 71Y-06 



Movable bed 



Experiment 71Y-10* 



Time (hr) 



Movable bed Fixed bed 



Experiment 71Y-06 



Movable bed 



Experiment 71Y-10 



0.102 
0.075 
0.039 
0.077 
0.079 
0.066 
0.045 
0.026 
0.034 

0.033 
0.019 
0.007 
0.024 
0.024 
0.005 
0.024 
0.030 
0.020 
0.035 
0.050 
0.038 
0.043 
0.050 
0.055 
0.053 
0.049 
0.033 
0.046 
0.048 
0.060 
0.049 
0.049 
0.047 
0.044 
0.048 
0.053 
0.058 
0.046 
0.050 
0.056 
0.048 
0.057 
0.055 
0.045 
0.055 
0.044 
0.039 
0.020 
0.032 
0.033 
0.040 
0.008 
0.033 

0.031 
0.050 
0.071 



0.057 
0.054 
0.040 
0.044 
0.048 
0.058 
0.059 
0.032 
0.048 
0.045 
0.058 
0.054 
0.054 
0.045 
0.060 
0.058 
0.059 
0.051 
0.047 
0.054 



0.079 
0.059 
0.077 
0.084 
0.089 
0.090 
0.106 
0.099 
0.088 
0.061 
0.055 
0.049 
0.045 
0.026 
0.045 
0.020 
0.018 
0.020 

0.020 
0.006 
0.038 
0.049 
0.023 
0.009 
0.029 

0.036 

0.048 

0.031 
0.052 
0.058 
0.065 
0.046 
0.040 
0.038 
0.060 
0.065 
0.048 
0.062 
0.067 
0.056 
0.072 
0.078 

0.059 
0.040 
0.025 
0.057 
0.053 

0.071 
0.069 
0.076 
0.071 
0.071 



104.0 


0.060 


109.0 


0.012 


114.0 


0.022 


119.0 


0.033 


124.0 


0.011 


129.0 


0.049 


134.0 


0.042 


139.0 


0.053 


144.0 


0.045 


149.0 


0.058 


154.0 


0.083 


159.0 


0.086 


164.0 


0.082 


169.0 


0.074 


174.0 


0.064 


179.0 


0.121 


184.0 


0.078 


189.0 


0.064 


194.0 


0.049 


199.0 


0.087 


204.0 


0.064 


209.0 


0.078 


214.0 


0.083 


219.0 


0.083 


224.0 


0.145 


229.0 


0.137 


234.0 


0.189 


239.0 


0.173 


244.0 


0.104 


249.0 


0.072 


254.0 


0.091 


259.0 


0.107 


264.0 


0.104 


269.0 


0.044 


274.0 


0.053 


279.0 


0.094 


284.0 


0.112 


289.0 


0.092 


294.0 


0.107 


299.0 


0.089 


304.0 


0.111 


309.0 


0.151 


314.0 





319.0 


0.214 


324.0 


0.176 


329.0 


0.067 


334.0 


0.068 


339.0 


0.045 


344.0 


0.051 


349.0 


0.062 


354.0 


0.083 


359.0 


0.178 


364.0 


0.118 


369.0 


0.159 


374.0- 


0.225 


375.7^ 


0.207 


376.5^ 


0.240 


378.0^ 


0.243 



0.056 
0.059 
0.046 
0.050 
0.065 
0.065 
0.070 
0.014 
0.074 
0.063 
0.042 
0.040 
0.051 
0.036 
0.074 
0.056 
0.044 
0.073 
0.068 
0.040 
0.066 
0.087 
0.104 
0.103 
0.105 
0.100 
0.112 
0.104 
0.110 
0.126 
0.134 
0.115 
0.129 
0.120 
0.076 
0.082 
0.091 
0.077 
0.110 
0.127 
0.106 
0.079 
0.073 
0.070 
0.053 
0.051 
0.089 



Fixed bed in experiment 71Y-10 not analyzed by this method. 

Not analyzed by this method. 

Standing wavelength 15.70 feet; standing wavelength was 7.0 feet at all other times. 



107 




52 o 



o 




3 


o 




cti 


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<u 






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o d o 



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108 




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109 



0.25 




• 
• • * / 


0.20 


_ 


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• 


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• • 


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♦^» 


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■ 

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iO.IO 


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n 


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0.05 0.10 0.15 0.20 0.25 

Kr, Automated Mettiod 

Figure A-4. Correlation o£ manual and automated Kj^'s, experiment 71Y-06 



0.20r 



0,15 



1 0.10- 



0.05 






... /. 




0.05 0.10 0.15 0.20 

Kr, Automated Method 

Figure A-5. Correlation o£ manual and automated Kn's, experiment 71Y-10. 



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