Foreshore sedimentation on a shelly beach, Indian Rocks Beach Florida

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Foreshore sedimentation on a shelly beach, Indian Rocks Beach Florida

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Title:
Foreshore sedimentation on a shelly beach, Indian Rocks Beach Florida
Creator:
Haney, Rebecca L.
Place of Publication:
Tampa, Florida
Publisher:
University of South Florida
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Language:
English
Physical Description:
xii, 128 leaves : ill. (some col.) ; 29 cm.

Subjects

Subjects / Keywords:
Coast changes -- Florida -- Indian Rocks Beach ( lcsh )
Beach nourishment -- Florida -- Indian Rocks Beach ( lcsh )
Dissertations, Academic -- Geology -- Masters -- USF ( FTS )

Notes

General Note:
Thesis (M.S.)--University of South Florida, 1993. Includes bibliographical references (leaves 87-94).

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University of South Florida
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Universtity of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
029674298 ( ALEPH )
29822599 ( OCLC )
F51-00102 ( USFLDC DOI )
f51.102 ( USFLDC Handle )

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FORESHORE SEDIMENTATION ON A SHELLY BEACH, INDIAN ROCKS BEACH FLORIDA by REBECCA L. HANEY A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Geology University of South Florida August 1993 Major Professor: Richard A. Davis, Jr., Ph.D.

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Graduate School University of South Florida Tampa, Florida CERTIFICATE OF APPROVAL Master's Thesis This is to certify that the Master's Thesis of REBECCA L. HANEY with a major in Geology has been approved by this Examining Committee on May 20, 1993 as satisfactory for the thesis requirement for the Master of Science degree Examining Committee: Richard A2ZDavis, Jr., Ph.D. Member: Sam B. Upchurch, Ph.D. Member: T. Stewart, Member:;?John W. Ph.D.

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ACKNOWLEDGEMENTS I would like to thank my major professor, Dr. Richard A. Davis, Jr., for his advice and suggestions throughout this project. I also thank Dr. Sam B. Upchurch, Dr. Mark T. Stewart, Dr. James c. Gibeaut, and Dr. John Haines for their guidance and review of this manuscript. The field work for this project was completed with the help of Barbara Belling, Gary Creaser, Kelly Cuffe, Ann Gibbs, David Inglin, Jason Kiefert, and Dan Press. Special thanks to Eric Shock, Eric Wright, David Inglin, and Wang Ping for their patience and assistance with the settling analysis of gravelsized particles. I also wish to express my gratitude to Jason Kiefert, who provided invaluable assistance, both in the field and in the laboratory.

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TABLB OF COIITENTS LIST OF TABLES .. iii LIST OF FIGURES . . iv ABSTRACT INTRODUCTION . . . . . . Beach Morphology . Location . . . . . . . . . . Indian Rocks Beach Nourishment Project Geologic Setting Previous Work . . Summary . . . . . . . . METHODS AND PROCEDURES Field Methods . Monthly . Continuous Tidal-Cycle Studies . . . Data Analysis . . Beach Profiles . . . Grain-size Analysis Hydrodynamic Analysis Wave Data . . . . . . . . Statistical Analysis SWASH SEDIMENTS . . Composition . . . . Particle shape and density . . Sediment distribution in the swash zone. Low vs. high energy levels ...... Hydrodynamically equivalent sediments Long-term change . . Summary . . . . . . . . PROFILES Plunge step Beach slope . Backswash ridges Swash width . Backbeach . . summary i X 1 4 6 11 14 14 24 26 26 26 30 30 31 31 32 33 39 40 43 43 44 46 54 62 63 65 67 67 7 1 7 5 78 79 81

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CONCLUSIONS . . . . . . . 83 REFERENCES CITED . 87 APPENDICES 95 APPENDIX 1 -BEACH PROFILES 96 APPENDIX 2 CHI DISTRIBUTION FOR THE SAND FRACTION OF SEDIMENT SAMPLES o o o 101 APPENDIX 3 CHI DISTRIBUTIONS FOR GRAVEL SIZE/SHAPE CLASSES o 107 APPENDIX 4 -WAVE AND TIDE DATA FROM THE USGS WAVE GAUGE 120 APPENDIX 5 -GRAIN SIZE PARAMETERS 122 APPENDIX 6 OUTPUT FROM PEARSON'S CORRELATION MATRICES o 125 ii

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Ll:ST OF TABLES Table 1. Gaps in USGS Wave Gauge Data 8 Table 2. DNR monument elevations and traverse azimuths . . . . . . 28 Table 3. variables used in Pearson's Correlation Matrix 42 Table 4. Properties of select sizejshape classes Table 5. Tide conditions, wave energy, and number of beach profiles surveyed for each tidal-46 cycle study . . . . . . . 67 Table 6. Characteristics of beach profiles used as input for Pearson's correlation matrix from the spring tide, low-energy study and the neap tide, low-energy study . . . . . 99 Table 7. Characteristics of beach profiles used as input for Pearson's correlation matrix from the spring tide, high-energy study . 100 Table 8. Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the spring tide, low-energy study. 24 hour times are indicated . 101 Table 9. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the spring tide, low-energy study. 24 hour times are indicated 102 Table 10. Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the neap tide, low-energy study. 24 hour times are indicated 103 Table 11. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the neap tide, low-energy study. 24 hour times are indicated . . 104 iii

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Table 12. Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the spring tide, high-energy study. 24 hour times are indicated 105 Table 13. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the spring tide, high-energy study. 24 hour times are indicated 106 Table 14. Average settling velocities (cmjsec), chi values, and phi sizes for gravel sizejshape classes . . . . . 107 Table 15. Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, low-energy tidal study . . . . . 108 Table 16. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, low-energy tidal study . 110 Table 17. Chi weight-percent distributions for the gravel fraction of the lower swash samples from the neap tide, low-energy tidal study 112 Table 18. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the neap tide, low-energy tidal study 114 Table 19. Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, high-energy tidal study ...... Table 20. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, high-energy tidal 116 study . . . . . . . . . 118 Table 21. Wave and tide data from the USGS wave gauge at R-75 used in the Pearson's correlation matrix . . . . . . . . 120 Table 22. Grain size and compositional data for the surface-sediment samples from the spring tide, low-energy study. Data used as input for the Pearson's correlation matrix . . 122 iv

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Table 23. Grain size and compositional data for the surface-sediment samples from the neap tide, low-energy study. Data used as input for the Pearson's correlation matrix 123 Table 24. Grain size and compositional data for the surface-sediment samples from the spring tide, high-energy study. Data used as input for the Pearson's correlation matrix 124 Table 25. Output from the Pearson's correlation matrix for the spring tide, low-energy study. Geologically significant correlation coefficients are shaded . 125 Table 26. output from the Pearson's correlation for the neap tide, low-energy study. Geologically significant correlation coefficients are shaded . . matrix Table 27. Output from the Pearson's correlation matrix for the spring tide, high-energy study. Geologically significant correlation 126 coeffients are shaded . . 127 Table 28. Output from the Pearson's correlation matrix for three tidal studies: spring tide, lowenergy: neap tide, low-energy: and spring tide, high-energy 128 v

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Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. LIST OF FIGURES Mean wave height (em) vs. mean tidal range (em), showing the classification scheme of Hayes (1979) (from Davis and Hayes, 1984) IRB=Indian Rocks Beach study area . Terminology used to describe parts of the beach. MHT = Mean high tide, MLT= Mean low tide level. .......... Location map of Pinellas County, Sand Key, and Indian Rocks Beach . . . . . Location of monuments R-70A through R-87, USGS wave gauge, and study area (See Figure 3) . . . . . . . Data collected from the USGS wave gauge at Indian Rocks Beach for February 1991 through March, 1992. A. Wave heights. B. Peak wave periods . . . . . . . . Location of Egmont channel source area for Indian Rocks Beach Nourishment Project Surface sampler used to collect top 1-2 em of sediment. Photograph taken looking down at the beach face . . Photographs of survey instruments used to collect beach profile data for December, 1990 through September, 1991. A. Optical transit. B. Electronic theodolite . Photographs of size/shape class for -2.5 t. A. Equant whole shells (Chione). B. Elongate whole shells (Area) Photographs of size/shape class for -2.5 t. A. Decomposed shell fragments. B. Mineralized shell fragments vi 2 5 7 9 10 13 27 29 35 36

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Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Photographs of size/shape class for -2.5 t. A. Elongate shell fragments. B. Equant shell fragments Photographs of sizejshape class for -2.5 t. A Lithic fragments. B. Phosphate . . Data from the USGS wave gauge at R-75 for tidal-cycle studies. A. Wave heights (em) B. Relative tide levels (em). .... Mean grain size (t) vs. percent calcium carbonate for surface-sediment samples from the spring tide, low-energy tidal study . Sediment data for surface-sediment samples vs. tide level data from the USGS wave gauge for the neap tide, low-energy tidal study. A. Mean grain size (t). B Percent calcium carbonate . Hourly weight-percent distributions of grain size data (t) for the upper swash surface-sediment samples for the neap tide, low-energy tidal study . Hourly weight-percent distributions of hydrodynamic data (X) for the upper swash surface-sediment samples for the neap tide, low-energy tidal study. A. Sand size fraction. B. Gravel-size fraction Hourly weight-percent distributions of grain size data (t) for the lower swash surface-sediment samples. A. Spring tide, low-energy tidal study. B. Spring tide, high-energy tidal study . . Hourly weight-percent distributions of hydrodynamic data (X) for the lower swash surface-sediment samples for the spring tide, high-energy tidal study. A. Sand size fraction. B. Gravel-size fraction . Hourly weight-percent distributions of hydrodynamic data (X) for the lower swash surface-sediment samples for the spring tide, low-energy tidal study. A. Sand size fraction. B. Gravel-size fraction . vii 37 38 41 48 49 51 52 55 57 58

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Figure 21. Percent gravel for surface-sediment samples and tide level data from the USGS wave gauge for the spring tide, high-energy tidal study . . . Figure 22. Sediment data for samples collected i n the swash zone at R-75 during the monitoring of the nourishment project 60 from January, 1991 through December, 1992 64 Figure 23. standard deviation of grain size for sediments collected in the swash zone at R-75 during the monitoring of the nourishment project from January, 1991 through December, 1992 . . . 65 Figure 24. Hourly beach profile data from the foreshore, for the neap tide, low-energy study at R-75. Tide levels are based on measured data from USGS wave gauge. Dashed line indicates bottom of plunge step through time . . . . 68 Figure 25. Beach profile data from the foreshore, for the 1200 survey of the spring tide, lowenergy tidal study at R-75. Both plunge steps, the berm crest and the NGVD datum are indicated . . . . . . . 70 Figure 26. Beach profile data for the foreshore from the 1000 and 1600 surveys at R-75 for the spring tide, low-energy tidal study. Predicted water levels, plunge step locations, and NGVD datum are indicated 72 Figure 27. Beach profile data for the foreshore from the 1230 and 1330 surveys at R-75 for the spring tide, low-energy tidal study. Predicted water level, plunge step location, and the NGVD datum are indicated 73 Figure 28. Swash zone beach slope and tide level data for the spring tide, high-energy tidal study 75 Figure 29. Photographs of backswash ridge at R-75. A. Facing north. B. Close-up of ridge with land towards the top of the page; the two scales are 4 inches and 10 centimeters 76 vii i

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Figure 30. Percent swash vs. tide level data from the USGS wave gauge. A. Spring tide, lowenergy tidal study. B. spring tide, high-energy tidal study . . 80 Figure 31. Beach profile data from the backbeach, for the 1230 and 1330 surveys of the spring tide, high-energy tidal study at R-75. The explanation indicates 24 hour time of each survey and the tidal stage (H=high; F=falling) . . . . . . . 82 Figure 32. Serial plot of beach profiles from the spring tide, low-energy tidal-cycle study at R-75 . . . . . . . . 96 Figure 33. Serial plot of beach profiles from the neap tide, low-energy tidal-cycle study at R-75 . . . . . . . . 97 Figure 34. Serial plot of beach profiles from the spring tide, high-energy tidal-cycle study at R-75 . . . . . . . . . 98 ix

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FORESHORE SEDIMENTATION ON A SHELLY BEACH INDIAN ROCKS BEACH, FLORIDA by REBECCA L. HANEY An Abstract Of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the Department of Geology at the University of South Florida August 1993 Major Professor: Richard A. Davis, Jr., Ph. D X

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Analysis of the hourly changes in beach profiles, wave climate, tide data, and surface-sediment samples from the swash zone during a single tidal cycle provide information about the patterns of sedimentation on the foreshore at Indian Rocks Beach, Florida. This beach was nourished in 1990 with material dredged from an ebb-tidal delta at the mouth of Tampa Bay with sediments composed of quartz sand, phosphate, broken shell, whole shell, and lithic fragments. The shells exhibit the greatest variation in shape, yet they can change both size and shape over a relatively short period of time due to abrasion and breakage. The range of grain sizes on the foreshore is fine sand to gravel; the sand fraction is dominated by quartz, whereas the gravel fraction is almost entirely carbonate of various types. The rate of change in sediment texture and composition within the swash zone is greatest when tide level is changing the most rapidly. The samples changed sequentially across the foreshore with varying tide level and wave energy conditions. As the tide rises, the energy level increases in the lower swash zone first, whereas on a falling tide, the energy level decreases at the top of the swash first. The patterns of change in sediments across the swash zone are due to shear sorting in the backswash. The xi

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increase in energy associated with the rising tide or increasing wave height alters the sediment interactions in the swash and backswash processes, and the surface sediments are dominated by shell, phosphate, and lithic fragments. As the tide falls, or wave energy decreases, the sediments are predominantly quartz sand. Greater variation in grain size and texture occurs during low-energy conditions than high-energy conditions due to the delicate balance between tide and wave influence. Swash sediments range in size from medium-sand to medium-pebble size during low-energy conditions, whereas during the high-energy conditions the range is only from coarse sand to medium-pebble size. The tides have the greatest influence on the foreshore sedimentation during low-energy conditions, whereas the waves are the most influential during high energy conditions. Abstract Approved: Major Professor, Richard A. Davis, Jr., Ph.D. Distinguished Research Professor Department of Geology Date 6f Approval xii

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1 INTRODUCTION The processes which influence the morphologic shape and size of a beach are complex, and often difficult to measure. The forces which act on a beach include currents, waves, tides, and winds. The relative dominance of waves or tides at the shore will determine which process has the greatest effect on coastal morphology. The west-central coast of Florida is characterized by low wave energy, a small tidal range, and a morphology which places it in the mixed energy coast classification of Hayes (1979); (Figure 1). A slight change in wave climate or tidal range can easily upset the equilibrium, and therefore change the dominant coastal process . The balance between waves and tides allows for the existence of coastal features characteristic of both waveand tide-dominated coasts within a few kilometers. The swash zone is the most dynami c section of the beach due to the interaction of waves, tides, sediment distribution, and the presence or absence of nearshore bars (Wright and Short, 1984). The temporal and spatial variations in these conditions result in a complex and sometimes unpredictable set of possible morphologies. The changes in morphology can occur at different frequencies and can involve variations in beach volume, beach state,

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5 _4 e 1M c.= a: -=: Q ,_2 z -=: ""' :E 1 . . . o 100 200 MEAN WAV'E HElG HT (em) 2 Figure 1. Mean wave height (em) vs. mean tidal range (em), showing the classification scheme of Hayes (1979) (from Davis and Hayes, 1984). IRB=Indian Rocks Beach study area.

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3 sediment distribution, or any combination of these factors. Much of the literature involving beach change has focused on large-scale variation. Some studies have focused on smallscale changes which occur in the swash zone, but few attempt to study areas where there are heterogeneous populations of sediments with different shapes, densities, and compositions. One of the most difficult populations to quantify is shell material due to the complex shape and density variations which occur among individual shells, between different species, and in comparison with the other sediment types. The hydrodynamic properties of the whole shells and shell fragments are significantly influenced by particle density and shape, resulting in a wide range of grain behaviors in response to the same wave conditions. In this study, patterns of change in the composition, hydrodynamics, size, and texture of the sediments at Indian Rocks Beach are compared to the wave climate, tidal range, and other environmental factors to determine their relative influence on the changes observed in the swash zone. The analysis is based on a comparison of sediment characteristics with wave and tide data, as well as beach profile changes, and environmental observations at discrete points in time. Sediment samples were collected hourly from stationary points in the swash zone over a tidal cycle to determine the effects of tide level, wave climate, and other environmental factors.

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4 Beach Morphology Terminology used in the literature to describe the parts of a beach is often inconsistent. This section will establish the names and definitions of each part of the beach as they will be used in this study. The backbeach, as shown in figure 2, is usually dry and is only acted upon by waves or covered by water during storms or extremely high tides. At Indian Rocks Beach the backbeach extends from the seawall to the berm crest. The seaward limit of the backbeach is characterized by a break in slope, called the berm crest. The foreshore is located seaward of this change in slope, and is defined as the zone regularly covered and uncovered by the rise and fall of the tides. The percent of the foreshore covered by water varies with the spring and neap tides. The swash zone is defined as the zone of active uprush and backswash of water. The seaward extent of the swash zone is the base of the plunge step, and the landward extent is the top of the active uprush, which varies with tide level and wave energy. The plunge step is located at the base of the swash zone, where the waves are actively breaking. This feature is characterized by a step-shaped morphology whose height varies with tide level in the study area. The steep face on the seaward side of the plunge step is called the plunge face. Anything seaward of the plunge step will be referred to as offshore.

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-OFFSHORE --t-FORESHORE -1BACKBEACH _swash_ zone MHT----------------------------berm crest Figure 2. Terminology used to describe parts of the beach. MHT =Mean high tide, MLT= Mean low tide level. U1

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6 Location Indian Rocks Beach is located on Sand Key (Pinellas county) along the west-central coast of Florida (Figure 3). sand Key is a 20 km long, narrow barrier spit bounded by Clearwater Pass to the north and Johns Pass to the south. The Pinellas County coast is a barrier-inlet complex with barrier spits and detached barrier islands (Davis and Andronaco, 1987). The orientation of the coastline changes at Indian Rocks Beach; the coast has a north-south trend to the north of the headland, and northwest-southeast trend to the south. The Gulf coast shoreface in Pinellas County has a very gentle gradient, which causes considerable attenuation of wave energy during the passage of fronts and major storms (Davis, 1989). The headland at Indian Rocks Beach has a steeper gradient across the inner shelf than the rest of the county; the gradient to the 3.5 meter contour at Indian Rocks Beach is 1:50, whereas the gradient is 1:308 at Clearwater Beach Island (see Figure 3), and 1:120 at Long Key to the south (McKenna, 1990). Because of the higher gradient, Indian Rocks is subject to higher wave energy than the rest of the county. Another unique characteristic of the Pinellas County coast is the irregular bottom configuration of the shoreface, caused by the outcrop of limestone bedrock and the presence of local sand bars (Davis, 1985). These shoreface characteristics affect the

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N Sand Key Indian Rocks Beach Study area Redington Treasure Island .... 0 .5 lOkm Pinellas Counly Figure 3. Location map of Pinellas County, Sand Key, and Indian Rocks Beach. 7

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8 wave climate along the shoreline, and therefore should also affect the longevity of the nourishment project. The Pinellas County coast is microtidal, with low to mixed energy conditions. The tides are typically <1 meter and are mixed with semi-diurnal cycles of unequal heights (Davis and Hine, 1989). wave heights average <30 em with 4 second periods during non-storm conditions (Tanner, 1960: Rosen, 1976). Wave data at Indian Rocks Beach have been recorded by a directional wave gauge deployed by the United states Geological Survey in January, 1991. The gauge is located 100 meters offshore from the post-nourishment shoreline at the Division of Natural Resources (DNR) monument R-75 (Figure 4). Data collected from February, 1991 to March, 1992 show a mean significant wave height of 0.36 meters, and a modal wave height of 0.25 meters (Figure SA), and a modal wave period of 6 seconds (Figure 5B). These means are slightly biased towards low-energy conditions due to gaps in data collection listed in Table 1. Table 1. Gaps in USGS Wave Gauge Data Started Collectinq stopped Collectinq February 5, 1991 February 22, 1991 May 20, 1991 June 27, 1991 August 1, 1991 August 21, 1991 August 28, 1991 September 27, 1991 October 4, 1991 October 14, 1991 November 1, 1991 December 29, 1991 December 31, 1991 February 17 1992

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0 N Study area Gulf of Mexic o lkm 9 Figure 4. Location of monuments R-70A through R-87, USGS wave gauge, and study area (See Figure 3).

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10 Significant Wave Height (m) 10 -* -e-d 0 = 0" 0 5 Peak Period (sec) Figure 5. Data collected from the USGS wave gauge at Indian Rocks Beach for February 1991 through March, 1992. A. wave heights. B. Peak wave periods.

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11 The annual wind rose has a distinct mode from the east which has little affect on the coast compared to that of the prevailing and predominant winds. During the spring and summer months (March-September), winds are out of the southwest to southeast. Daily afternoon thunderstorms of short duration are common in the summer months, but they are localized and have a limited effect on coastal processes. During the winter months (November-March), predominant winds are out of the north to northeast associated with the west to east passage of frontal systems (Davis and Hine, 1989). Most of the energy which affects this coast is associated with the large waves created by onshore winds associated with these frontal systems. The orientation of the coastline and the shoreface gradient are such that a divergence of littoral drift direction occurs at Indian Rocks Beach. Localized changes in the general littoral drift direction also occur with changing wind and storm patterns. Indian Rocks Beach Nourishment Project Indian Rocks Beach was nourished in 1990 as the second part of a three-phase beach management plan for Sand Key. The first phase involved nourishment of North Redington Beach and Redington Shores in 1988, while the third phase involved nourishment of Indian Shores in 1992 The sediment source for Indian Rocks Beach nourishment was the ebb-tidal

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12 delta of Egmont channel (Figure 6). The sediment dredged from the channel was transported by barge approximately 32 km to the nourishment site. The sediment was pumped from the barges onto the beach in a slurry, and then bulldozed to form the design profile. Dredging began in September, 1990, and was completed in December, 1990. The project design called for 1.0 million cubic meters placed on about 4.2 km of beach. The nourishment area extends from DNR monument R71A through R85 (Figure 4). The construction profile was designed with a berm width of between 80 and 115 meters and a berm elevation of 1.8 meters above Mean Low Water (MLW); (U. S. Army, 1989). The monitoring of this project was carried out by the coastal Research Laboratory, University of South Florida Geology Department and the u. s. Geological survey in st. Petersburg, Florida from March, 1990 to December, 1992. The monitoring consisted of onshore and offshore beach profiles, sediment samples from several locations along each profile, wave data, wave-refraction analysis, and shoreline maps from aerial photographs. Although the nourishment project is 4.2 km long, this study will focus on a 350 m-long section of the beach. The study area includes three profile lines associated with the Division of Natural Resources benchmarks on Sand Key; monuments R-74A, R-75, and R-75A (Figure 4). The majority of the field work and data collection is focused on the

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N Nourishment Area GULF OF MEXICO Borrow Area 0 s lOkm 13 PINELLAS COUNTY TREASURE ISLAND EGMONT KEY Figure 6. Location of Egmont channel source area for Indian Rocks Beach Nourishment Project.

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foreshore at monument R-75, which is located approximately 1000 meters south of the northern extent of the nourished beach. Geologic setting 14 The position of the barrier islands along the Pinellas County coast relative to the mainland is partly controlled by the bedrock underlying the Holocene sediments (Evans et al., 1985; Davis and Hine, 1989). The bedrock is composed of a Miocene unit which dips gently to the southeast; the Arcadia Formation is predominantly limestone and dolostone containing varying amounts of quartz sand, clay and phosphate grains (Scott, 1988). This unit is unconformably overlain by sediments of Pleistocene and Holocene age, which range from 0 to 20 m in thickness. In the study area, the Holocene sediments are 4,000 5,000 years old (Stapor and Matthews, 1980; Davis and Kuhn, 1985). The sediment supply for the barrier system is primarily derived from the shoreface of the barriers themselves, and the composition of the native beach sediment is bimodal, consisting of fine quartz sand and shell gravel. Previous Work One of the most interesting aspects of a beach involves the dynamic changes which are constantly occurring in response to waves, tides, currents, and storms (Komar,

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15 1976). Cycles of change have been studied at temporal scales of variation ranging from minutes to decades, and spatial scales from centimeters to kilometers. The recognition of seasonal changes in beach profiles which occur in areas such as southern California (Aubrey, 1979), eastern Massachusetts {Hayes, 1972), and Delaware (Dubois, 1989) has been widespread. These changes are caused by the influence of seasonal variations in wave frequency and height on the nearshore distribution of sediments (Aubrey, 1979). Others, such as Camfield (1991), focus on the longterm cycles of change and emphasize the importance of considering longer reaches of coastline. Although the processes of beach and wave interaction have been discussed in studies by Gorsline (1966), Clifton {1969), Fox & Davis (1976), Aubrey {1979), Bryant {1982), Bowles (1991), Camfield (1991), Dean (1991), and many others, beaches with shell are rarely addressed due to the complex hydrodynamic nature of shell particles caused by variations in shape and density. Limited analysis of shell has been performed in association with beach nourishment monitoring studies, such as Herrygers {1990), to determine the affects of shell on the longevity of beach fill. Other research includes the analysis of differential separation of right and left valves of pelecypod shells on beaches by Nagle {1964); the comparison of wave and current oriented shells by Nagle {1967); estimation of energy level and

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16 average breaker height using size analysis of shell debris by Austin (1970); the description of fair-and foul-weather shell accumulations on a Georgia Beach by Frey (1988), and the examination of beach shell accumulations in relation to onshore and alongshore processes by Dorjes et al. (1986). The sediments on the surface of the swash zone at Indian Rocks Beach contain 5% to 95% gravel which is composed of shell, phosphate and lithic fragments. The other main constituent is fine quartz sand. The effects of composition and sorting of grains on the hydrodynamic characteristics which affect particle behavior in the swash zone have been studied extensively by Sneed and Folk (1958), Briggs et al. (1962), Folk and Robles (1964), Hand (1967), Maiklem (1968), Gibbs et al. (1971), and Matthews (1991). The swash zone varies in time with changing wave and tide conditions and the rate of change in sediments can vary spatially with environmental conditions (Wright and Short, 1984). Bryant (1982) emphasized that the existence of grain-size and sorting patterns on the foreshore is universal regardless of sediment size and wave-energy levels. This is due to the fact that the swash is the zone of maximum sediment movement, and the sediment-water interface is always active, regardless of the relative energy level (Howard and Reineck, 1981). Some of the variables which have been studied to explain changes occurring in swash sediments include wave

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17 climate, tidal range, sediment size and composition, interaction of tides and ground-water levels in the foreshore, and bedslope. Sediment supply and longshore currents also play a dominant role in determining the nature of the beach (Chauhan et al., 1988). Gorsline (1966) compared beach profiles, sediment distributions, wave conditions, water characteristics, and wind speed for fifteen different beach stations in northwest Florida. A similar study was conducted by Hogue (1991) at four locations along the west-central coast of Florida, which also discussed the presence of shell in these locations. The changes which occur in sediment composition and texture in response to these environmental changes are complex, and they can vary greatly between study areas. Bryant (1982) set up a classification of beaches according to their morphology, sediments, currents, and the transport of coarse sediments in comparison with fine sediments. on dissipative beaches dominated by littoral transport, such as those in Pinellas County, the coarse particles (such as shell) undergo preferential movement over fine particles due to the greater particle intrusion through the viscous boundary layer into the turbulent flow zone, where the shear force required for incipient motion is greatly reduced. Clifton (1969) found similar patterns when working with coarse materials. Selective transport of coarse over fine particles results from stratification

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18 within the bedload transport during backswash. This process is related to the high concentration of particles within the bedload which places the flow mechanically in the region where the effects of grain inertia dominate (Inman and Filloux, 1960; Kuenen, 1968). The textural sorting which occurs during backswash is also important in determining the composition of the sediments found on the surface of the swash zone. Inman et al. (1966) and Sallenger (1979) found that the dispersive pressure between sediment particles tends to segregate the coarser grains of any particular density toward the top of the flow and the finer grains of the same density toward the base of the flow within a moving layer of densely concentrated particles, such as the backswash. For grains of equal size, those with greater densities work their way towards the bottom of the flow relative to the less dense grains. Inman et al. (1966) defined this segregation of grain sizes as shear sorting. Coarse, denser particles are therefore under the influence of higher current velocities and can travel faster than the smaller, less-dense particles. Because this process separates grain sizes, Moss (1972) found that it also results in better sorting of sediments in the backswash. As the flow decelerates in the backswash, the finer particles closer to the bed will settle out first, then the coarser particles will be deposited on the bed surface, available for re-entrainment and transport.

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19 This segregation of grain sizes and densities is analogous to the forces which govern debris flows. Hampton (1979) looked at the presence of coarse granular solids in debris flows which were supported within a clay-water matrix by buoyancy. The grains which were coarser than the competence of the flow required a certain level of dispersive pressure to remain in transport. Duncan (1964) studied the affects of water table and tidal cycle fluctuations on sediment distributions in the swash zone. He found that the tide-level fluctuations above and below the general water table caused the zone of deposition to shift its position within the swash-backwash zone. The swash water, after crossing over the intersection of the water table with the foreshore surface, rapidly percolates into the sand. The reduction of water volume is accompanied by a significant decrease in velocity and the deposition of sediment carried in suspension (Sonu, 1972). Thus, deposition is facilitated above the interface of the water table and foreshore until the beach slope changes sufficiently to increase backswash velocities and prevent further net accretion. However, on a coarse beach, the backswash velocities were significantly decreased due to increased percolation. Duncan (1964) also noted a 1-3 hour lag of the water table behind the tide. Because the surface sediments of the swash zone are in equilibrium with the existing wave climate, tide range, and

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20 other factors already discussed, they can be very useful indicators of change. There are many descriptors which could be used to characterize sediment samples; grain size, settling velocity, and grain shape are just a few. Matthews (1991) emphasized that the method of analysis should be designed around the information which is needed about the sediments. For example, if the purpose is to describe the hydrodynamic properties of sediments which affect their behavior in a moving fluid during entrainment, transport and deposition, he recommended the use of settling velocity. Because particle mobility in fluids (air, water) is dependent on the ratio between shear velocity and settling velocity, the settling velocity distribution is argued to be more valid for the characterization of sand texture than sieve-determined size distributions (Middleton, 1976; Bridge, 1981). Although there are several formulae used to calculate values similar to sedimentation diameter, Syvitski et al. (1991) emphasize that there is still no agreement on the formulae used to convert settling velocity to an equivalent particle diameter. Matthews (1991) suggests that a combination of methods may be necessary to obtain a complete description of the sediments if they contain many different grain shapes and densities. Reed et al. (1975) found that settling analysis was more valuable because the results exhibited hydraulically important modalities that result

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21 from variations in settling velocities through the interrelationships of grain size, shape, and density. Size analysis using sieves may result in grain-size distributions unrelated to the hydromechanical properties of the sediment. Komar and Reimers (1978) found that settling velocities of sediment grains from a river determined whether they were transported by bedload or suspended load. The parameters of the settling tube which can have an affect on the settling velocity of particles include tube diameter, length, fluid temperature, fluid salinity, and calibration of the tube. These parameters have been studied at length by Payne and Pell (1960), Alger and Simmons (1968), Muir Wood (1969), Gibbs et al. (1971), Taira and Scholle (1977), Vanoni (1975), Middleton and Southard (1978), Mehta et al. (1980), May (1981), Allen (1984b), Syvitski et al. (1991), and numerous others. Their work involved the calculation of a correction coefficient for Stoke's Law and Reynolds number, which allows comparison of spherical and non-spherical particles by taking into account the affects of inertia, boundaries in the fluid, particle shape and surface roughness. The Corey Shape Factor is another parameter which has been used to show the influence of surface area and volume of on fall velocity (Krumbein, 1941; Komar and Reimers, 1978; Baba and Komar, 1981). The stability of a falling shell can greatly influence its fall velocity and turbulence (Mehta et al., 1980). The

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22 factors which control the stability of freely falling mollusk shells were described by Allen (1984a) to be the drag coefficient, relative loading, particle elongation, and particle flatness. Steady fall is restricted to particles with relatively equant valves of little to moderate flatness. Unsteady fall is typical of relatively flat and elongate particles. A terminal settling velocity is reached when the upward draft acting on the sinking shells equals the downward-acting immersed weight (Mehta et al., 1980). Valves of all studied species eventually fall concave-up, in their most hydraulically stable position (Menard and Boucot, 1951; Clifton and Boggs, 1970; and Braithwaite, 1973). The interaction with other particles can complicate these standard behaviors described for individual shells. Extensive work has been done to quantify the relationships between grain size, density, shape, settling velocity, and other characteristics which affect the hydraulic properties of the particles in a moving fluid. Glass spheres have been used to estimate terminal settling velocities for commonly occurring sands, such as quartz. The spheres simplify analysis because they do not have as much variation in shape and density as natural particles (Hallermeier, 1981). The application of this work can be limited due to the significant differences between spherical and non-spherical particles. The drag coefficient is greater for non-spherical grains than it is for spheres, due

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23 to the increased ratio of surface area to mass, particle rotation during settling (Graf, 1971), and the presence of edges and corners (Folk and Robles, 1964). Surface roughness increases the drag coefficient and causes the transition to turbulence to occur at a lower Reynolds number than it would for smooth grains (Graf, 1971; Allen 1984b). If the edges of the particle are made rough by breakage (ex: shell fragments) than the drag coefficient increases sharply (Folk and Robles, 1964; Williams, 1966; Graf, 1971; Syvitski et al. 1991). Mitchell-Tapping (1977) determined the swash zone to be the zone of highest shell abrasion. Additional experiments on shell breakdown were done by Driscoll (1967), who determined that shells with higher surface area to weight ratios abrade faster. His results were based on experiments with mollusc shells in two different beach environments: one with fine sand and the other with gravelly sand. He found more abrasion occurred with the presence of gravel, therefore concluding that the grain size is of overriding importance in determining the modification of valves by abrasion. A comparison of his results with those conducted in a tumbling barrel by Chave (1964) showed that the experiments in the tumbling barrel produced much more rapid abrasive affects on shell material than moderate surf action. The abrasive reduction achieved in two hours by Chave approximated the reduction of 100 hours in the surf

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zone found by Driscoll. Additional studies by Driscoll (1970) found that shell destruction is 150 to 1000 times more rapid in surf zones where abrasion is the principal agent, than it is in low energy sublittoral environments. 24 The breakdown of skeletal material was examined by Upchurch (1970) in sediments on the Bermuda Platform. He studied mechanical attrition as well as the separation and concentration of many skeletal materials according to their resistance to attrition differentiation using observations on the Platform and tumbling-barrel experiments. His results showed that skeletons of calcareous organisms tend to break into predictable size fractions, controlled by the architecture of the test, not mineralogy. Force (1969) studied the abrasion of sediments from Siesta and Casey Keys on the west coast of Florida. He found that a wide variety of mollusc shells break down into three preferred size ranges. These sizes appeared to be related to the basic architectural units of the shells. summary Although many studies of swash zone sedimentation have been cited, few have examined the interaction of shell with other sediments. The processes which occur in the swash zone are complex and difficult to measure when sediments are uniform in shape and density. Therefore, the added complication of a study area where the sediments have

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heterogenous shapes, densities, and compositions has not been addressed in much detail. 25 Some of the research discussed in this section addresses differences in particle density and shape, such as Inman et al. (1966), Clifton (1969), Sallenger (1979), and Bryant (1982). Their work explains some of the sorting processes which occur in the swash zone in the presence of different grain sizes and densities. The interaction of the water table and tide level is also very important to the swash and backswash processes (Duncan, 1964; Sonu, 1972). The complexity of these processes increases where grains of varying shape and density, as well as sediments with a mixture of compositions occur. Shells are one of the most complex grain types, yet they have received very little attention in sedimentation studies. Although the processes associated with the presence of many grain types are complex, more attention needs to be focused on them in order to better understand coastal environments in which the sediment shapes and compositions are diverse.

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26 METHODS AND PROCEDURES The types of data collected for this study include beach profiles, surface-sediment samples, wave data, tide data, and weather data. The data were collected on several different time scales: monthly, continuously, and hourly over a tidal cycle. Field work began in January, 1991 and was completed in April, 1992. Field Methods Monthly Four surface-sediment samples were taken across the shoreface at each of three DNR monuments, R-74A, R-75, and R75-A, located along the seawall at 150 meter intervals (Figure 4). The surface samples were designed to represent the sediments in equilibrium with the wave and tide conditions at the time of sampling. Therefore only the top 1-2 em of sediment was collected from each site with the sampler shown in figure 7 Four samples were taken; one each at the top, middle, and bottom of the swash zone, and a fourth sample was taken at -1 meter water depth. The samples, collected on a monthly basis, were not used extensively in this study.

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27 Figure 7. Surface sampler used to collect top 1-2 em of sediment. Photograph taken looking down at the beach face.

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28 Beach profiles were surveyed from DNR monuments R-74A, R-75, and R-75A to 1.2 meters below the National Geodetic Vertical Datum (NGVD). The elevations of the monuments and the azimuths along which the surveys were conducted are listed in Table 2. NGVD represents the mean sea level of 1929. The surveys were conducted using a White transit, model Realist TR-300, and standard stadia rod for December 1990 through August, 1991, and a Sokkia SET 4B electronic theodolite and a prism mounted survey rod for September, 1991 through April, 1992 (Figures SA & SB). Beach-profile surveys were conducted by taking distance and elevation readings perpendicular to the shoreline at 6 meter intervals, or closer where changes in morphology occur. Offshore profiles were measured every three months on the same day as the onshore profiles. A sled-mounted prism is used to measure the offshore profiles to a depth of 4.5 meters below NGVD. Table 2. DNR monument elevations and traverse azimuths. Monument Azimuth Elevation (m) R-74A 285 2.83 R-75 280 2.77 R-75A 282 2.70 Environmental observations made at each monument include: wind speed and direction, nearshore wave height,

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A B Figure 8. ..,. --... ... -. 29 --. Photographs of survey instruments used to collect beach profile data for December, 1990 through September, 1991. A. Optical transit. B. Electronic theodolite.

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30 breaker height, wave period, direction prior to breaking, swash width, presence or absence of cusps on the foreshore, and distribution of shell and sand across the swash zone. Photographs of the sample sites, profile orientation, and textural distributions were taken, and sketches were drawn of the morphologic features present. Continuous A directional wave gauge was deployed offshore at DNR monument R-75 by the USGS in January, 1991. Cables run from the offshore pressure transducers underneath the beach to a data acquisition system located on the shore. Data collection began in February, 1991 with sampling occurring every 8 hours for 24 minute periods. The sampling interval was modified to every 6 hours in March, 1991. The gauge was set up for hourly data collection as needed to coincide with hourly sediment sampling for this study. The data were downloaded directly from the shore station and processed by the USGS office in St. Petersburg, Florida. The significant wave heights, peak periods, and central angles were calculated according to Herbers and Guza ( 1989) and Kuick et al. ( 1988) Tidal-Cycle Studies The monthly sampling encompassed only one point in time, which was usually during relatively low wave-energy

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32 and swash zone were calculated from the distance and elevation coordinates obtained from ISRP. To facilitate the comparison of swash zone widths between tidal-cycle studies, the percent swash was calculated by dividing the swash width by the foreshore width. Thus, the percent swash is a function of relative tide level and wave energy. The values for beach slope, swash width, foreshore width, and percent swash are listed in Appendix 1. Grain-size Analysis Sediment samples were rinsed three times with distilled water, dried, and split using a Humboldt Splitter to obtain two 30-50 gram subsets per sample. One subset of each sample was sieved at half phi (t) intervals from -2 t to and including 4 t using a mechanical sieve shaker for a period of five minutes. The shorter-than-normal sieve time was designed to prevent shell breakage during analysis. The sediments retained on the -2 t sieve were hand shaken through a sieve stack consisting of -4, -3.5, -3, -2.5, and -2 t sieves. Each fraction of sediments retained on the sieves from -4 to 4 t was weighed, placed in a pre-weighed beaker, and immersed in a 10% solution of hydrochloric acid to dissolve the carbonate material. The samples were then rinsed three times with distilled water, dried, and reweighed. The individual weight percentages for each half

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33 phi before and after the carbonate was dissolved were entered into two LOTUS 123 spreadsheets which calculated the cumulative weight-percent distribution of carbonate. Hydrodynamic Analysis The second subset of each sediment sample was divided into sand (-1.0 4.0 t) and gravel (-4.0 --1.5 t) fractions. Approximately one gram of the sand fraction was introduced into a settling tube with a diameter of 12.5 em and a fall length of 190 em. The chi distribution for each sample was calculated using Sedidat (Wright and Thornberg, 1988). Chi (X) is a log transform which is a function of settling velocity: Equation 1 where s is settling velocity in metersjsecond and s0 is a standard settling velocity of 1 meterjsecond (Wright & Thornberg, 1988). Because the chi scale is logarithmic, the data could be easily compared to grain-size data in phi, which is also a logarithmic scale. The individual chi weight-percentages were entered into a spreadsheet program which standardizes the weight-percents, and calculates cumulative weight-percent for each chi distribution. The individual weight-percent distributions for the tidal-cycle study samples are listed in Appendix 2.

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34 In order to analyze the gravel fraction of the tidalcycle study samples, 50 -75 gram subsets from ten of the monthly samples were combined to obtain a representative population of shell, phosphate, and lithic fragments in the beach fill at R-75. The gravel fraction of these samples was divided first into half phi sizes, and then into 6-8 classes of similar shapes and densities per half-phi size. Grains from each of the shape classes are shown in figures 9-12. The grains in each sizejshape class were dropped individually in a settling tube with 45 em diameter and 190 em fall length. Settling times were measured for each shell with a stopwatch. The number of grains dropped per size/shape class was determined by the variance within the class. A spreadsheet program was used to calculate the settling velocity for each grain, average settling velocity of each size/shape class, and the variance within the class. The average settling velocities and equivalent chi values for each size/shape class are presented in Appendix 3. To determine the chi distribution for the gravel fraction from each of the tidal-cycle study sediment samples, the grains were divided into half-phi units. The percentage of each sizejshape class was visually estimated, and the data entered into a spreadsheet program which calculates the weight-percent of sediment in each size/shape class. The assumption made in this calculation is that all clasts have the same density within each sizejshape class.

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A 0 5 CM 10 CM 8 5 CM Figure 9. Photographs of sizejshape class for -2.5 t. A. Equant whole shells (Chione). B. Elongate whole shells (Area) 35

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A 0 5 CM 10 CM B Figure 10. Photographs of sizejshape class for -2.5 t. A. Decomposed shell fragments. B. Mineralized shell fragments. 36

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A 0 5 CM B 0 5 CM Figure 11. Photographs of size/shape class for -2.5 t. A. Elongate shell fragments. B. Equant shell fragments. 37

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38 A 0 5 CM 10 CM 8 0 5 CM Figure 12. Photographs of sizejshape class for -2.5 t. A. Lithic fragments. B. Phosphate.

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39 Individual weight-percent distributions of gravel in each size/shape class for the tidal study samples are listed in Appendix 3. Densities were measured for some of the size/shape classes to determine the amount of variation which affects the hydrodynamic properties of the sediments at Indian Rocks Beach. The shells for each class were weighed, then put into a 25 ml graduated cylinder which could be read to the nearest tenth ml. The density was calculated by dividing the mass by the change in the volume of water in the cylinder. wave Data Data obtained from the USGS wave gauge were expressed in terms of Julian Days and Greenwich Mean Time. These were converted to month/day format and Eastern Standard Time. The deep-water wavelength and wave steepness were calculated as follows: 0 21t H wave Lo Equation 2 Equation 3 where L0 is deep water wavelength, g is the gravitational constant, T is wave period, and Hsia is significant wave

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40 height. Wave steepness was used as an additional variable to characterize the wave climate. All wave parameters for each tidal study are listed in Appendix 4. Based on the data collected from the wave gauge from February, 1991 through March, 1992 (Figures SA & 5B), the conditions experienced during low-energy tidal studies are the most common, occurring 15% of the time. The conditions during the spring tide, high-energy study occurred less than 1% of the time, while the conditions during the neap tide, highenergy study occurred 4% of the time. Figure 13A shows the wave-height distributions during all four tidal studies. The pressure readings collected by the wave gauge were averaged to determine the mean water level, which was subtracted from the raw data to obtain relative tide levels. The hourly tide levels calculated for the tidal-cycle studies are compared in figure 13B, and listed individually in Appendix 4. statistical Analysis The method of moments was used to calculate the mean and standard deviation for the grain-size distributions from the tidal-cycle sediment samples. A Pearson's correlation matrix was used to determine the geologic significance of relationships observed between the sediment samples, wave climate, tide conditions, and environmental observations. The variables used as input for this matrix are listed in

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2 1.5 --6/26/91 -o-8/1/91 --9/3/91 -o-2/6/92 .. .J: OJ Q) 1 ::1: CD 3: 0 5 0 ... 600 900 1200 1800 2100 24 Hour Time 40 --6/26/91 -o-8/1/91 --9/3/91 20 E -2/6/92 .. C5 > CD 0 ...J CD .... -20 ; s CD a: -40 600 900 1200 1500 1800 2100 24 Hour Time Figure 13. Data from the USGS wave gauge at R-75 for tidal-cycle studies. A. Wave heights (em). B. Relative tide levels (em). 41

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42 Table 3. The actual values from the tidal-cycle studies, which were used as input for the matrix, are listed in the following appendices: beach profile data in Appendix 1, wave and tide data in Appendix 4, and grain-size parameters in Appendix 5. The correlation coefficients (r values) were determined by running the matrix through ABSTAT version 6.03. Those correlations with an r value of >0.7 or <-0.7 will be referred to as "geologically significant", because they indicate that more than 50% of the variability can be accounted for by the linear relationship between the two variables being compared (Upchurch, personal communication, 1993). Correlations with values >0.39 or <-0.39 are statistically significant at an alpha level of 0.05. Several different matrices were used; one for each tidalcycle study data set, and one with data from the three studies combined. The correlation coefficients output by ABSTAT are presented for all four matrices in Appendix 6 Table 3. Variables used in Pearson's Correlation Matrix Sediments Profiles Waves & Tides Mean grain size Swash width Wave height Standard deviation Foreshore width Wave Period % CaC03 % swash Wave angle % Gravel Beach slope Wave steepness Tide level

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43 SWASH SEDIMENTS During the neap tide, high-energy tidal-cycle study, there was a sand bar present at the base of the plunge step which was emergent for several hours at low tide. Due to the size of the bar, the waves were breaking seaward of or on top of the bar for most of the tidal cycle. The swash zone, as previously defined, was therefore not affected by the same processes as the other tidal studies. The processes observed in the swash zone during the other studies were occurring on the seaward side of the bar. Therefore, the sediment samples taken in the swash zone were not comparable to the other three tidal studies. The results presented will only compare the three similar studies (the spring tide, low-energy study on 6/26/91, the neap tide, low-energy study on 9/3/91, and the spring tide, high-energy study on 2/6/92} and will not include the results from the fourth study (the neap tide, high-energy study on 8/1/91). Composition The sediments at Indian Rocks Beach are composed of quartz sand, phosphate, broken shell, whole shell, and lithic fragments. The range of grain sizes present in the

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44 surface sediments collected during the tidal-cycle studies is fine sand to gravel (4.0 to -4.0 t). The only mud-or silt-sized particles are found seaward of the plunge step where wave enerqy is less dominant, or occasionally in small percentages on the backbeach. The beach fill for the nourishment project does contain some small-to medium-sized boulders, but these are usually found on the backbeach or seaward of the plunge step. The quartz grains are fairly homogeneous fine-to medium-sized sands, the shells range from carbonate mud to pebble-sized grains, while the other constituents of these sediments can range from medium sandsized grains to pebbles. Particle shape and density Particle shape and density vary greatly with composition at Indian Rocks Beach, with the most variation occurring among the shell taxa. Some of this variation is evident in the size/shape classes for the -2.5 t shells shown in the photographs in figures 9-11. The physical and chemical alteration of the whole shells subsequent to their original deposition in the beach nourishment source area also influences their density and shape. The decomposed shell class in figure lOA contains shell fragments which have been chemically, biologically, or physically broken down. In the swash zone, the shell particles are easily broken and abraded in the presence of constant but variable

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45 wave action. This breakdown occurs over a relatively short period of time in comparison with other grains such a phosphate and quartz. Further studies need to be conducted in the laboratory and at the beach to determine the rate of abrasion for the shells at Indian Rocks Beach. Information about the breakdown of these shells would be useful to the study of sediment transport, and distribution in the swash zone. The shells may break down into a few preferred size ranges, similar to those located approximately 60 km to the south of the study area in Sarasota, Florida, which were studied by Force (1969). Because the breakdown is related to shell architecture, the abrasion and breakage of shells should also be a factor in future beach sedimentation studies (Force, 1969; Upchurch, 1970). Based on monthly observations of swash sediments from January, 1991 to April, 1992, there are cycles of whole shell input and abrasion which take place at Indian Rocks Beach. As more beach fill is eroded by a high-energy storm event or frontal system, whole shells enter the system at the foreshore, and then break or abrade slowly into smaller shell fragments. The length of these cycles is determined by the spacing between high-energy events, the recovery between events, and by the amount of beach fill eroded by each event. The lithic fragments have a very irregular shape whose angularity increases with grain size, due to the large

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46 spells present in these rocks. The phosphate particles also exhibit a variety of shapes, ranging from spheres, to plates, to rods. The densities measured for some of these size/shape classes are listed in Table 4. Other known densities include quartz (2.65 gjcm3), calcite (2.71 gjcm3), and aragonite (2.95 gjcm3), which are constituents of the lithic fragments. Table 4. Properties of select sizejshape classes. Phi size Size/Shape Settlinq vel. Chi Value Density (I) Class (emf sec) (X) (q/CID.:s) -3.0 Whole Arks 17.35 2.53 2.43 -3.0 Sm. whole 16.65 2.59 2.81 -3.0 sm. whole 16.65 2.59 2.94 -3.0 Lithic 33.51 1. 58 3 .14 fragments -3.0 Phosphate 32.83 1.61 2.76 -2.5 Lithic 30.04 1.73 2.64 fragments -2.5 Phosphate 31.56 1.66 2.64 -2.0 Whole bivalves 12.58 2.99 2.59 -2.0 Lithic 29.56 1.76 3.73 fragments -2.0 Phosphate 28.07 1.83 2.63 -1.5 Whole bivalves 12.61 2.99 2.90 Sediment distribution in the swash zone The distribution of grain size and composition across the swash zone varies with wave energy and tide level. Whole shell, lithic fragments, phosphate, and broken shells

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47 in the coarse sand to gravel size range may be found in the plunge step and in the landward reaches of the swash zone. The active swash zone varies the most in composition and texture; the relative percentages of quartz sand, phosphate, and broken shell in the surface sediments varies with tidal stage, and wave energy. The mean grain size (t) of the surface sediment samples is well correlated with the percent calcium carbonate; correlation coefficients are -0.91 or better. Figure 14 from the spring tide, low-energy tidal-cycle study shows the grain-size data and percent carbonate values for upper and lower samples which plot along a straight line. The correlation coefficient is -0.98 for percent carbonate and mean grain size, which is very significant. The gravel present in the sediments is all carbonate, and the quartz population is fine sand. Therefore, in order to see a decrease in grain size (t), the percent carbonate in the samples must increase. The patterns of change in the surface-sediment grain size and composition are directly correlated to the rising and falling tides in all three studies. The sediments coarsen and percent carbonate increases as the tide rises while they fine and percent carbonate decreases as the tide falls. This relationship is demonstrated in figures 15A & 15B for data from the neap tide, low-energy tidalcycle study. The correlation coefficient for mean grain

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48 0 0 0 o Upper swash o Lower swash 80 0 0 0 0 60 0 0 0 tP 40 0 0 0
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o Upper swash -o-Lower swash _._Tide level __ 630 830 1030 1230 1430 1630 1830 2030 80 60 40 20 o Upper swash -<>-Lower swash --Tide level Time (24 hour) 630 830 1030 1230 1430 1630 1830 2030 Time (24 hour) 49 Figure 15. Sediment data for surface-sediment samples vs. tide level data from the USGS wave gauge for the neap tide, low-energy tidal study. A. Mean grain size (t). B. Percent calcium carbonate.

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50 are usually found at the top of the active swash, where they are deposited due to their buoyancy. The rate at which changes in sediment texture and composition occur in the surface sediments is also important to consider. The fastest rate of change in mean grain size and percent carbonate for the neap tide, low-energy study samples coincide with the fastest rate of tide-level change. Most of the shift in grain size and carbonate occurs in the first two to three hours after the tide change due to the different hydrodynamic conditions on the beach face. Once the new equilibrium condition is reached in the sediment, the grain size and percent carbonate stay relatively constant for about five hours. The rate of change did vary between rising and falling tides; change occurred faster on a rising tide than on a falling tide. For example, in figure lSA the sediment distribution fines gradually over at least five hours as the tide falls. However, the sediment at this site coarsens very quickly as the tide rises, with the change only taking three hours. The same patterns of gradual and quick change at this sample site are reflected in the phi and chi weight-percent distributions shown in figures 16, 17A & 17B. Although these figures show only the data for samples collected in the lower swash, the same patterns were present in the upper swash. The rate of change in sediment composition, size, and texture is related to the wave energy and tide level. When

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1700 1500 1300 1100 900 700 2 0 301 u 1 0 0 . . ... ....................... ................... -2 1 0 Phi 1 I Upper Swash I ............... ... 2 3 51 High Tide Low TJdl High T1d8 4 Figure 16. Hourly weight-percent distributions of grain size data {t) for the upper swash surfacesediment samples for the neap tide, low-energy tidal study. the tide level begins to change, the energy conditions in the swash zone are affected. The energy levels increase on a rising tide, and decrease on a falling tide. The sediments in the surface of the swash zone respond to these changes within minutes. The thickness of sediments on the surface which is affected by the variations in energy conditions will be greater for higher levels o f energy, and therefore will increase as the tide level increases. The collection of surface samples during the tidal-cycle studies was more difficult when the tide just started to rise, or just started to fall because the thickness of sediments in

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53 equilibrium with the waves was 1 em or less. As the tide level continued to change, the thickness of sediments in equilibrium with the waves increased. The thickness of this layer varies with the depth of disturbance by the waves (Clifton, 1969). No measurements of the layer's thickness were taken in the field, but observations were made with respect to the relative changes in the depth of disturbance. The more energy in the swash zone, the thicker the layer of sediments disturbed by the waves. During the spring tide, high-energy study, the sediments in the swash zone exhibited the greatest thickness of sediment in equilibrium with the waves because of the high wave energy level, and relatively large depth of disturbance. During the low-energy tidalcycle studies estimates of the depth of disturbance ranged from 1-5 em, whereas during the high-energy surveys, they were 5-15 em. The upper and lower swash samples taken hourly during the tidal-cycle studies display the same pattern of change in sediment size, composition, and texture, but the change does not occur simultaneously for both samples. As the tide rises, the lower sample is affected first, whereas the upper sample is affected first as the tide falls. In figure 15A the upper samples shift to the finer grain size before the lower samples as the tide level falls between the 730 and 1030 surveys, with the lower sample attaining a similar mean grain size as the rate of change slows at the 1130 survey.

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54 The energy conditions decreased in the upper swash first, and as the tide fell, the energy conditions continued to decrease in the rest of the swash. The lower samples coarsen before the upper samples as the tide rises between the 1330 and 1730 surveys (Figure 15A). In this case, the increase in energy caused by the rising tide changes the conditions in the lower swash first, with the changes gradually moving landward as the tide rises. Low va. biqb enerqy levels The amount of variation in sediment size, composition, and texture which occurs over a tidal cycle was less durinq the high-energy tidal-cycle study, than it was for the lowenergy tidal-cycle studies. Figures 18A & 18B demonstrate the changes in grain size which occurred in the lower swash samples from the spring tide, low-energy study and the spring tide, high-energy study. The mean grain size change as the tide fell between the 1200 and 1900 surveys of the spring tide, low-energy study, was approximately 5 t. The change for the spring tide, high-energy study was only 2 t as the tide fell between the 1230 and 1930 surveys. The surface samples for the 1000 and 1100 surveys are omitted from figure 18A due to sampling error. The difference in the amount of change in grain size between low and high energy conditions is similar for the upper swash samples collected during these two tidal-cycle studies.

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55 I Lower Swash j A ......... / ........ } : -. \ LowTKie High Tide 2 3 4 Figure 18. Hourly weight-percent distributions of grain size data (t) for the lower swash surfacesediment samples. A. Spring tide, low-energy tidal study. B. Spring tide, high-energy tidal study.

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The chi weight-percent distributions exhibit less variation than the phi distributions in the lower samples from the spring tide, high-energy study (Figure 19A) in comparison with the spring tide, low-energy study samples (Figure 20A). There is a shift of approximately 2 chi for the spring tide, low-energy study during the rising tide, whereas the shift is only about 0.5 chi for the spring tide, high-energy study during the rising tide. Even though the shift in the chi distribution is small for the high-energy study (Figure 19A), as the tide falls the variance of the chi distribution increases whereas the phi distribution does not show a corresponding increase (Figure 18B) The spring tide, low-energy samples did not demonstrate a similar change in variance (Figures 18A, 20A). Although the chi data in figures 19A and 20A represent only the sand fraction, the gravel analysis supports these findings. Figure 19B shows the weight-percent distribution of gravel as a function of the entire sample weight. The amount of gravel in the chi plot increases around high tide, and the chi range in which this data plots demonstrates more shift in the chi range toward the lower chi values. The chi weight-percent distribution of the gravel fraction for the spring tide, high-energy study is presented in figure 18B. The amount of gravel is greater around high tide, but the chi range in which it plots is almost the same as the sand fraction. Therefore, the gravel doesn't show any additional

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4) E ... :::l 0 : "' A "I j 20 1 0 0 1930 1730 1530 1330 1100 .............................. ... ..................... 930 ........ .. ..................... .................. ...... ..... .......... 730 0 1 2 3 4 5 8 7 8 Chi 8 "I GRAVB. Lower Swash : ............................. ....................... _______ ......... ..................... ---.... 4----.. '"' I : Low Tide High Tide Low Tide .. ..... .. . .... .... ... .. .. .. ... .... .. .. .. ..... .. .. .. .. .... . . .. .... . 1330 -t J High llde 1100 930 0 t .. .............. 1 2 3 4 Chi 5 6 7 8 57 Figure 19. Hourly weight-percent distributions of hydrodynamic data (X) for the lower swash surface-sediment samples for the spring tide, high-energy tidal study. A. Sand-size fraction. B. Gravel-size fraction.

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Q) E I= .... :J 0 J: C\1 Q) E I= A 1700 1500 1300 1100 900 700 B SAND Lower Swash "I .... 20 .c 011 u 10 0 ----------------..... ..................................... .......................................... 0 1 2 I GRAVEL Lower Swash 30 I 20 u 10 0 Low Tide H i gh Tide 3 4 5 6 7 8 Chi Low Tide 1700 1100 900 .. .... .......................... ............................................................ .. . ...... ... ....... 700 0 1 2 3 4 Chi 5 6 7 8 High Tide 58 Figure 20. Hourly weight-percent distributions of hydrodynamic data (X) for the lower swash surface-sediment samples for the spring tide, low-energy tidal study. A. Sand-size fraction. B. Gravel-size fraction.

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59 shift in chi at high tide. The relative wave heights for these two studies are given in figure 13A; the spring tide, low-energy study had a mean wave height of 0.13 meters, while the spring tide, high-energy study had a mean wave height of 1.3 meters. The composition and texture of the sediments also changed more during the spring tide, low-energy tidal study than during the spring tide, high-energy tidal study. The range of grain sizes present provides some information about the composition and texture of the sediments. The quartz grains are only found in the medium-to fine-grained sand sizes, and the coarse sand and gravel fraction of the samples is all carbonate material. Therefore, the fact that the percent gravel never exceeded 60% in the spring tide, high-energy study {Figure 21), indicates that some of the carbonate in the swash was sand-sized. The total percent calcium carbonate for the lower swash samples ranges from 5% to 98% for the spring tide, low-energy study and from 67% to 98% for the spring tide, high-energy study. Because the carbonate content doesn't drop below 67% carbonate in the spring tide, high-energy study samples, and the percent gravel is relatively low, most of the sand fraction must be carbonate material, not quartz sand. Therefore there was less compositional variation during this study than during the spring tide, low-energy study. Because all the carbonate present was within the coarse sand-sized sediments

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80 so 40 20 830 1030 1230 1430 Tune (24 hour) <>-Upper swash -Lower swash level 1630 1830 60 Figure 21. Percent gravel for surface-sediment samples and tide level data from the USGS wave gauge for the spring tide, high-energy tidal study. for the spring tide, high-energy study, the carbonate would have been almost all broken shell particles. The spring tide, low-energy study contained grains from fine sand to gravel, some of which were whole shell, broken shell, phosphate, lithic fragments, and quartz sand. Therefore the amount of textural variation was greater during the spring tide, low-energy tidal-cycle study than it was during the spring tide, high-energy study. The reason for the different amounts of change in sediment size and composition during low-and high-energy conditions deals with the delicate balance between wave and

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61 tide influence on the west-central coast of Florida (Davis, 1987). During low-energy conditions, the tide range has the most influences the amount of variability which occurs in the swash sediments, because it limits the affect of the waves on the foreshore. During high-energy conditions, the wave energy has the most influence on the swash zone and therefore limits the amount of variability in the sediments; there was less variation because only one specific range of sizes and compositions was in equilibrium with the narrow range of energy conditions present. The tide range of 0.6 m had less influence on the changes in sediments than the waves did. According to Davis and Hayes (1984), dominance of a particular process is strictly relative; it is not based on any absolute wave or tide parameters. Therefore, because the waves had more affect on the sediments during the highenergy study, the most influential force was the waves. The minor changes which did occur in the sediment size and settling velocity of the sediments collected during the spring tide, high-energy study were due to changes in wave height, which correspond to the changes in tide level (Figures 13A & 13B). Likewise, in the spring tide, lowenergy study, the tides were the most influential process because the variations in sediments were affected most by changes in tide level.

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62 Hydrodynamically equivalent sediments The hydrodynamic properties of the sediments also have an affect on the grain-size distribution present at any given point in the tidal cycle. The chi distributions are used as indicators of the hydrodynamics of each sediment population. At high tide during the spring tide, low-energy study, the grain-size distribution has a distinct bimodality in the surface samples taken during the 900 and 1200 surveys (Figure 18A). (Surveys for 1000 and 1100 hours are omitted due to sampling error). These two modes occur at -1.0 phi and -3. 0 phi. The chi distribution for the sand fraction of these samples shown in figure 20A does not show the same bimodality. Because the gravel fraction of the sample was removed, the chi gravel distribution in figure 20B must also be taken into account. These data show the gravel plotting within the same range as the modal population of the sand fraction in figure 19A. Therefore the two distinctly different grain sizes are hydrodynamically equivalent. This illustrates the point made by Matthews {1991), that the relationship between energy levels in the swash zone and the sediment size is not as simple as coarsening grain size for higher wave energy. Due to the many shapes and densities present in the samples, it is possible for two different sized grains to be present in equilibrium with the waves. They can be quartz and shell, phosphate and quartz, or any other combination of compositions and densities.

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63 Lonq-term chanqe The grain-size data from sediment samples taken alonq the entire nourishment project at Indian Rocks Beach were examined to determine if any long-term trends exist. The samples collected during the nourishment monitoring consisted of one 15 em core taken at each profile in the active swash zone. The location of the sample is not consistent, and the depth of the sample varies greatly. The mean grain size, percent calcium carbonate, and standard deviation of the sediment samples collected at R-75 during the monitoring for 1991 and 1992 are shown in figures 22A, 22B, and 23. There is a slight decrease in the mean grain size over the two year period, and there are also seasonal cycles; the grain size coarsens during the winter months when storms are more frequent, and fines during the summer months. Because the samples consist of 15 em cores taken at various points in the tidal cycle the data are relatively noisy. The percent calcium carbonate increased slightly (Figure 22B), and the standard deviation was relatively constant for the two year period (Figure 23). In order to define the long-term changes occurring in the sediments at Indian Rocks in more detail, the sampling plan would have to be modified. Most of the variation in sediment composition, size, shape, and texture occurs over a tidal cycle. In addition, there are cycles of abrasion and breakage in the shell which influence the grain size of the

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64 A 4 3 2 s 1 c 0 -c m -1 -2 I I 1991 1992 8 100 m u 00 E 0 u c 0 1991 1992 Figure 22. Sediment data for samples collected in the swash zone at R-75 during the monitoring of the nourishment project from January, 1991 through December, 1992. A. Mean grain size. B. Percent calcium carbonate

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I j 2 1 0.5 0 1991 1992 Figure 23. Standard deviation of grain size for sediments collected in the swash zone at R-75 during the monitoring of the nourishment project from January, 1991 through December, 1992. sediments on the foreshore. The sampling would have to be 65 more closely spaced than the monthly monitoring in order to document the temporal variability in these cycles. The method of sampling should also be modified. The amount of sediment collected, as well as the location of the sample should be uniform. The method of sampling should also be changed: surface samples are more useful than the 15 em cores to characterize the sediments present in the swash zone. The cores may collect material from two or three previous tidal cycles. sw=acy There is a great deal of compositional, size, and textural variation within the sediments at Indian Rocks

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66 Beach. The differences in hydrodynamic behavior are due to composition, shape and density variations among the particles. The shells exhibit the most variation in shape and settling behavior in the water column. They can also change shape over a relatively short time due to breakage and abrasion. The rate of change in sediment texture and composition was greatest when the tide level was changing the most. The direction of change in the surface sediments samples with varying tide level and wave energy was related to the section of the swash zone affected first. As the tide rose, the changes occurred in a landward direction, while on a falling tide, the change occurred in a seaward direction. The distribution of grain size and composition across the swash zone varies with wave energy and tide level. The patterns of change in the surface sediments are directly correlated to the variation in tide level and wave energy for all three studies; the tides are the most influential process during the low-energy studies, and the waves are the most influential during the high-energy studies. This also determined the relative amount of change in the sediment size and texture. During the higher energy conditions there was less change in the grain size, composition, and hydrodynamic properties of the sediments because only one specific range of sizes and compositions was in equilibrium with the narrow range of energy conditions present.

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67 PROFILBS Beach profiles were surveyed hourly during each tidalcycle study for thirteen hours, or as daylight and weather permitted. The number of profiles completed for each tidal study, as well as the relative tide conditions and wave climate are listed in Table 5. Table 5. Tide conditions, wave energy, and number of beach profiles surveyed for each tidal-cycle study. Tidal study Tides Waves f Profiles June 26, 1991 Spring Tide Low energy 13 September 3, 1991 Neap Tide Low energy 14 February 6, 1992 Spring Tide High energy 9 Plunqe step The changes in the beach profiles over a tidal cycle occurred primarily in the swash zone, where sediment was actively being transported. The greatest variation occurred in the relative size, shape, and position of the plunge step. In figure 24, the profile data collected on the lower foreshore are plotted for each hour of the neap tide, lowenergy study. The plunge step moved approximately 4 meters seaward as the tide fell from 800 to 1400 hours, and

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1900 1700 1500 G l: 1100 900 700 76 n 78 79 80 81 82 Distance fran mcrunant (metars) 83 84 68 High Tide Low Tide High Tide Figure 24. Hourly beach profile data from the foreshore, for the neap tide, low-energy study at R-75. Tide levels are based on measured data from USGS wave gauge. Dashed line indicates bottom of plunge step through time. 1.5 meters landward as the tide began to rise from 1500 to 2000 hours. These estimates of movement are based on the data points surveyed at the top and bottom of the plunge step. The movement of plunge step is due to changing wave energy and tide level (Miller and Zeigler, 1959). These factors combine to vary the location at which waves break on the beach. Because the plunge step at Indian Rocks was located wherever the energy of the breaking waves was greatest, the location of the plunge step was translated landward during a rising tide, and seaward during a falling tide.

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69 During the spring tide, low-energy and neap tide, lowenergy, tidal-cycle studies, a second plunge step feature formed as the tide rose. In figure 25, the profile data for the lower foreshore taken during the 1200 survey of the spring tide, low-energy study show the presence of two plunge steps. The landward plunge step was located at the point where waves were breaking, and was made up of loosely packed gravel sized shell, with some phosphate and lithic fragments. The seaward plunge step was composed of wellpacked quartz sand, and some sand-sized shell and phosphate. Both plunge steps moved landward as the tide rose, but the wave energy was not sufficient to move the entire step feature as the tide rose. The reason only select sediment sizes and compositions are moved landward is related to the segregation of grain sizes and densities; the coarser, less dense grains are segregated toward the top of the large concentration of sediments in the water column where the waves are breaking. This segregation is due to the dispersive pressure between the moving particles (Inman et al., 1966; Sallenger, 1979). Coarser particles are therefore under the influence of higher current velocities and can travel faster than finer particles. The two studies in which two plunge steps were observed did have different tidal ranges; the spring tide, low-energy study had a tide range of 0 .96 meters, and the neap tide, low-energy study had a range of 0.75 meters. The mean wave

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70 1.3 ._.__ Berm crest 1 w '-a> 0.7 CD E .---Plunge steps c: .Q 0.4 co > J CD w 0.1 NGVD 65 68 71 74 n 80 83 Distance from monument (meters) Figure 25. Beach profile data from the foreshore, for the 1200 survey of the spring tide, low-energy tidal study at R-75. Both plunge steps, the berm crest and the NGVD datum are indicated. heights were 0.12 meters for the spring tide, low-energy study, and 0.21 meters for the neap tide, low-energy study (Figure 13). The profile data collected during the spring tide, high-energy study did not extend to the base of the plunge step for every survey due to extremely high wave energy. Therefore, the relative position of the plunge could not be documented, but a second plunge step was not observed near high tide. Of the hundreds of beach profiles taken near high tide at Indian Rocks Beach, few have exhibited this double plunge step. If additional data points had been taken in the swash zone, the presence of two

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71 plunge steps could have been documented more frequently. The monthly profiles were usually surveyed at relatively low wave energy conditions similar to the two low-energy tidal studies. Further observation of the sediment composition and texture present in the plunge step would be necessary during various wave and tide conditions to determine the conditions necessary for the complete landward translation of the plunge step with a rising tide. The other characteristics of the plunge step which changed over a tidal cycle were the size and shape. In figure 26, the height of the plunge step decreased from 1.2 m at the 1000 survey (high tide) to 0.3 m at the 1900 survey (close to low t ide). The changes in height occurred as the plunge step moved seaward with the falling tide and decreasing wave energy. The gradual landward translation of the plunge by the waves is responsible for the variation in plunge height. The plunge face flattens out as sediment is translated landward, spreading over a wider area, and decreasing the height of the plunge. Beach slope Landward of the plunge step, the swash zone also experienced changes in slope over a tidal cycle. The profile data measured with the optical transit for the first three tidal-cycle studies were not precise enough to measure these changes. For the spring tide, high-energy study,

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1 0.7 tn ... .s 0.4 c: 0 i w 0.1 -0.2 -0.5 70 Water level 1000 .... -........ ...... \. l-1ciiOHl Water level1600 \ . ..,.Plunge steps NGVD 73 76 79 82 Distance from monument (meters) 72 Figure 26. Beach profile data for the foreshore from the 1000 and 1600 surveys at R-75 for the spring tide, low-energy tidal study. Predicted water levels, plunge step locations, and the NGVD datum are indicated. however, the electronic theodolite was used, and much more precise data were obtained. In figure 27, the beach slope decreased as the tide fell from the 1230 survey to the 1530 survey. The wave heights during this study also decreased from about 1.6 meters to 1 .15 meters as the tide level fell between the 1230 and 1930 surveys (see Figure 13). Therefore, these results can be interpreted as a flattening of the beach face with falling tide or decreasing wave height. The decrease in slope corresponds to the fining of sediments on the beach face as discussed in the previous section. The beach slope data for the e ntire spring tide

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73 2 1 5 F -Water level 1230 (I) 1 '-CD ... CD E c ..Q 0.5 t ... Water level 1530 as > . NGVD CD 0 [j .... {).5 \ Plunge step .-\ .............. -1 55 58 61 64 67 70 73 76 79 Distance from monument (meters) Figure 27. Beach profile data for the foreshore from the 1230 and 1330 surveys at R-75 for the spring t ide, low-energy tidal study. Predicted water level, plunge step location, and the NGV D datum are indicated. high-energy study are shown in figure 28. The data show a decrease i n beach slope as the tide level fell between the 1230 and 1430 surveys. No additional surveys were conducted after 1530 due to rain. There was not a geologically significant correlation between the beach slope and the measured wave heights, or the measured tide levels i n the Pearson's correlation matrix for this tidal-cycle study. For w a v e height and beach slope, the r-value was 0.5, and for tide level and beach slope, the r-value was only -0.3. N either of these correlations are geologically significant, but they are statistically significant at the 0.05 alpha level.

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74 The decrease in beach slope with falling tide is associated with the changes in the surface sediments in the swash zone. As the tide falls, the wave energy affecting the swash also decreases. The surface sediments in the swash zone become finer, dominated by quartz sand, and the beach slope flattens out. Duncan (1964) documented similar changes in the swash during a study in southern California. The variations in beach slope which occur over a tidal cycle at Indian Rocks Beach are small (only 2-3 degrees). Although change in beach slope were observed in the field, they could not be documented by the beach profile data collected for this study. The elevations of each data point surveyed with the optical transit for the first three tidalcycle studies, were not accurate enough to measure changes of this scale. The data collected with the electronic theodolite for the spring tide, high-energy tidal study were much more accurate, but the data still did not document the changes. Very closely spaced data points (on the order of 0.3 m or less) surveyed with the total station may be able to measure these changes. Other methods, such as the placement of metal rods vertically in the surface of the foreshore, have accurately documented the changes in sediment elevation which occur in the swash zone (Duncan, 1964; Clifton, 1969). A technique similar to this may be necessary to detect the small changes which occur in the beach slope at Indian Rocks over a tidal cycle.

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7 5 60 -+-Beach slope ....... Tide level 7 (I) a> a> .... E 0 6 5 a> s en 6 u cu 5.5 5 630 830 1030 1230 1430 1630 1830 Time (24 hour) Figure 28. Swash zone beach slope and tide level data for the spring tide, high-energy tidal study. Backsvash ridqea A backswash ridge formed on the foreshore just above 75 the active swash zone as the tide rose. The ridge, shown in figures 29A & 29B, is oriented parallel to the shoreline, and formed on a rising tide just above the active swash zone where waves only reach every fourth or fifth wave. The ridge has 2-3 em of relief, is discontinuous along the beach, has an average length of 3 meters, and forms at a change in beach slope. The surface sediments landward of the ridge are primarily fine quartz sand. They comprise a thin veneer of approximately 1 em which i s underlain by

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76 A 8 Figure 29. Photographs of backswash ridge at R-75. A. Facing north. B. Close-up of ridge with land towards the top of the page; the two scales are 4 inches and 10 centimeters.

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gravel-sized shell, phosphate, and lithic fragments. The sediments seaward of the ridge are gravel-sized shell, phosphate, and lithic fragments. There were several of these ridges present along the shore with similar sediment characteristics and lengths. 77 The top of the uprush washed up over this ridge, with permeability decreasing as the water reached the fine sand on the landward side of the ridge. As the backwash occurred, there was flow separation over the ridge, and permeability was noticeably greater when the water began to flow over the shell on the seaward side of the ridge. The relief on the slip face of the ridge increased with each successive backwash. There appeared to be a change in beach slope at this ridge, with the seaward side having a steeper slope than the landward side. This change is due to the contrast in sediment size, composition, and texture across the The variation which occurs in the surface sediment as the tide rises, begins at the base of the swash and progress landward. The increase in energy associated with the rising tide level alters the sediment interactions in the backswash. A situation similar to that described by Inman et al. (1966) and sallenger (1979) occurs, where the dispersive pressure between particles in the backswash tends to segregate coarser and finer particles. The finer particles settle out first as the flow decelerates, leaving the coarse shell

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78 particles on top. This process takes place as the tide level rises, and thus increases the energy level in the swash zone to a point where the grain segregation can take place in the backswash. The backswash ridge forms just landward of this critical velocity. Therefore, the surface sediments landward of the ridge are quartz sand, because they have not been affected by the higher velocity backswash yet. The change in permeability across the backswash ridge affects the increase in relief (Figure 29B). As the backswash begins to move seaward across this ridge, the permeability increases sharply as the water moves over the ridge which separates the quartz sand and shell sediments. The permeability of the shelly sediments and the increased turbulence which occurs around the shell fragments causes some erosion at the base of the ridge, therefore increasing the relief. The increase in turbulence around shell fragments is caused by the presence of edges and corners on the broken shell (Folk and Robles, 1964). The surface roughness increases the drag coefficient and causes the transition to turbulence at a lower Reynolds number than for smooth grains (Graf, 1971; Allen 1984b). swash width The swash width changes in magnitude according to the wave energy and tide level; the width increases as the tide

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79 level rises, and decreases as the tide falls. All swash widths, foreshore widths, wave heights, and tide levels for the tidal studies are listed in Appendix 1. To compare the changes in swash width between tidal-cycle studies, the percent swash is calculated (swash width/foreshore width). This calculation standardizes the swash width and takes into account the wave climate and tide level to facilitate the comparison of changes between tidal studies. In figures 30A & 30B the percent swash is compared with tide level for the spring tide, low-energy tidal study and the spring tide, high-energy tidal study. From these two graphs, the response of swash width to tide level appears similar. The percent swash increases with tide level, and starts to fall after the tide level begins to drop. The correlation coefficient for percent swash and tide level is 0.87 for neap tide low-energy study, 0.95 for the spring tide, lowenergy study, and 0.97 for spring tide, high-energy study. These relationships correlate with the processes of increasing wave energy with increasing tide level. Backbeach The changes which occur on the backbeach at Indian Rocks Beach are usually wind-dominated, and therefore take place over a much longer period of time than a tidal-cycle study. The only time water reaches the backbeach is during storm conditions, or unusually high tides.

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A100 60 80 ....._Tide level 40 80 20 -60 ..0 ., cu 4) 0 > tn 40 0 -20 E: 20 -40 0 600 800 1000 1200 1400 1600 1800 24 Hour Time 8120 60 -+%swash ....... Tide level 40 100 20 -80 ..0 ., cu 4) 0 > tn 60 0 -20 E: 40 -40 630 830 1030 1230 1430 1630 1830 24 Hour Time Figure 30. Percent swash vs. tide level data from the USGS wave gauge. A. Spring tide, low-energy tidal study. B. Spring tide, high-energy tidal study.

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81 Some minor changes did occur on the backbeach during the spring tide, high-energy study. The swash actively washed over the berm from the 930 survey through the 1430 survey. The highest rate of deposition on the backbeach occurred between the 1230 and 1330 surveys (Figure 31). The sediments deposited range in size from mud to gravel. The gravel-sized particles were washed up as bedload in the swash, and were deposited as the velocity of the water decreased. Near high tide there was approximately 0.3 meters of standing water on the backbeach, allowing time for fine sediments to settle out of suspension on top of the gravel overwash deposits. summary The spatial and temporal changes in plunge step location, size, and shape, were influenced by wave and tide conditions as well as the shear sorting of sediments in the swash zone. The amount of sorting which occurs is dependent on the wave energy and tide level. The segregation of grain sizes and densities in the backswash influences the composition of grains which form the second plunge step near high tide in the presence of low wave energy conditions. The relative position of the plunge step is determined by the increasing wave energy levels which affect the lower foreshore as the tide rises and falls.

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82 -1230 H -1330 F (/) '-G) Backbeach -1.9 G) Berm crest E . . ..... c: 0 :;:; co > 1 6 G) w 1 3 1 0 10 20 30 40 50 60 70 Distance from monument (meters) Figure 31. Beach profile data from the backbeach, for the 1230 and 1330 surveys of the spring tide, highenergy tidal study at R-75. The explanation indicates 24 hour time of each survey and the tidal stage (H=high; F=falling).

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83 CONCLUSIONS Sedimentation on the foreshore at Indian Rocks Beach is complex, due to the variations in composition, density, size, and texture of the sediments. The range of sediment sizes present on the foreshore is fine sand to gravel. The sand fraction is dominated by quartz sand with some carbonate, whereas the gravel fraction of the sediments is almost all carbonate; the lithic fragments contain minor amounts of quartz. Therefore the mean grain size of the sediments is directly related to the percent calcium carbonate. There are significant amounts of variability in the hydrodynamic properties of the whole shell and shell fragments.in the swash zone; the shells exhibit more change in size and shape over time than the other sediments due to breakage and abrasion. As the number of rough edges increases, so does the drag coefficient which affects the behavior of each particle in water. These results provide a field example of the work done by Syvitski et al. (1991) which compares the hydrodynamic properties of particles with different compositions, shapes, and densities using a settling tube. The settling velocity of shell fragments decreases as the drag increases, causing the shell particle

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84 to be hydrodynamically equivalent to a smaller size particle. This hydrodynamic equivalence of different size particles due to variations in shape has been observed in laboratory experiments, but has not been documented in many sedimentation studies conducted in the field. The sediment interactions in the swash zone at Indian Rocks Beach are similar to the processes described by Inman et al. (1966), Clifton (1969), Sallenger (1979), and Bryant (1982). In the sediments with which they worked, increasing grain size was directly related to increasing density. Most shell material at Indian Rocks Beach is coarser than the quartz sand, but their average density is less than that of quartz. In addition, the turbulence around the shell particles due to their shape causes their behavior in water to be even more unpredictable. The patterns of change in sediments across the swash zone are due to shear sorting which occurs primarily in the backswash. The increase in energy associated with the rising tide or increased wave height alters the sediment interactions in the swash and backswash processes. When the energy levels in the swash zone increase, there is preferential movement of the coarse particles over fine particles due to increased intrusion through the viscous boundary layer into the turbulent flow zone, where the shear force required for incipient motion is greatly reduced. This is accentuated by the increase in turbulence around the

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shell fragments due to their corners, edges, and curved shape (Folk and Robles, 1964). The finer particles settle out first as the flow decelerates, leaving the coarser particles on the surface of the swash zone. Thus, the surface sediments are dominated by gravel-sized shell, phosphate, and lithic fragments. As the tide falls, the backswash energy decreases, the turbulent flow in the backswash decreases, and fine quartz sand particles become the dominant grains in the surface sediments. 85 The changes in the beach profile which occur over a tidal cycle are the location, size, and shape of the plunge step, as well as small variations in the beach slope. The relative position of the plunge step is determined by the increasing wave energy levels which affect the lower foreshore as the tide level rises or wave heights increase. The changes in size and shape of the plunge step are due to movement of the plunge step, and are also determined by the sorting of sediments in the swash zone. Greater variation in grain size and texture occurs during low-energy conditions in comparison with high-energy conditions due to the delicate balance between tide and wave influence. swash sediments range from fine quartz sand to coarse shell gravel during the low-energy conditions, whereas the sediments in the swash zone during the highenergy conditions range from coarse sand-size to fine pebble-sized shell fragments, phosphate, and lithic

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86 fragments. During the low-energy conditions, the tide range controls the amount of variability which occurs in the swash sediments. During the high-energy conditions, the wave energy influences the swash zone the most and therefore limits the amount of variability in the sediments: there is less variation because only one specific range of sizes and compositions is in equilibrium with the narrow range of energy conditions present. This delicate balance between wave and tide influence has been documented on a larger scale by Davis and Hayes (1984) and Davis (1987). The high-energy conditions under which wave influenced sedimentation patterns were observed occurred less than one percent of the time at Indian Rocks Beach in 1991. The low-energy conditions were the most frequent, occurring 15% of the time in 1991. The events in which the energy level is sufficient for the waves to influence.the sedimentation patterns are the frontal systems, which are relatively short in duration, occurring mostly in the winter months. Therefore, tides influence the sedimentation at Indian Rocks Beach for a greater proportion of time than waves. Wright and Short (1984) found that although the morphology of a beach at any point in time is a function of the sediment characteristics, wave climate, and tide conditions, the long term beach will tend to exhibit the most frequently occurring state. At Indian Rocks beach, the modal state is tide influenced.

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REFERENCES CITED Alger, G. R., and Simons, D. B., 1968. Fall velocity of irregular shaped particles: Journal of the Hydraulic Division, v. 94, p. 721-737. Allen, J R. L., 1984a. Experiments on the settling, overturning and entrainment of bivalve shells and related models: Sedimentology, v. 31, p. 227-250. 87 Allen, J. R. L., 1984b. Experiments on the terminal fall of the valves of bivalve mollusks loaded with sand trapped from a dispersion: Sedimentary Geology, v. 39, p. 197209. Aubrey, D. G., 1979. Seasonal patterns of onshore/offshore sediment movement: Journal of Geophysical Research, v. 84, p. 6347-6354. Austin, H. M., 1970. Shell debris and shoreline energy on Florida Gulf beaches: Florida Academy of Sciences Quarterly Journal, v 33, p. 90-96. Baba, J., and Komar, P. D., 1981. Measurements and analysis of settling velocities of natural quartz sand grains: Journal of Sedimentary Petrology, v. 51, p. 631-640. Birkemeier, w. A., 1989. The Interactive survey Reduction Program: Department of the Army, Kitty Hawk, NC. Bowles, w. D 1991. The effect of bedslope on bedload transport and erosion threshold for fine-grained, noncohesive sediments at low roughness Reynolds numbers and lower flat-bed flow regime: Unpublished masters thesis, Department of Marine Science, University of South Florida. Braithwaite, c. J. R., 1973. Settling behavior related to sieve analysis of skeletal sands: Sedimentology, v. 20, p. 251-262. Bridge, J. s., 1981. Hydraulic interpretation of grain-size distributions using a physical model for bedload transport: Journal of Sedimentary Petrology, v. 51, p. 1109-1124.

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Briggs, L. I., McCulloch, D. s., and Moser, F., 1962. The hydraulic shape of sand particles: Journal of Sedimentary Petrology, v. 32, p. 645-656. 88 Bryant, E., 1982. Behavior of grain size characteristics on reflective and dissipative foreshores, Broken Bay, Australia: Journal of Sedimentary Petrology, v. 52, p. 431-450. Camfield, F. E., 1991. When erosion is not erosion: Proceedings of the 1991 National Conference on Beach Preservation Technology: Florida Shore and Beach Preservation Association, Tallahassee, FL, p. 194-201. Chauhan, 0. s Verma, V. K., and Prasad, c., 1988. Variations in mean grain size as indicators of beach sediment movement at Puri and Konarak beaches, Orissa, India: Journal of Coastal Research, v. 4, p. 27-36. Chave, K. E., 1964. Skeletal durability and preservation, IN: Imbrie, J., and Nurall, N., (eds.), Approaches to Paleoecology, J. Wiley & Sons, p. 377-387. Clifton, H. E., 1969. Beach lamination: nature and origin: Marine Geology, v. 7, p. 553-559. Clifton, H. E., and Boggs, s., 1970. Concave-up pelecypod (Psephidia) shells in shallow marine sand, Elk River Beds, Southwestern Oregon: Journal of Sedimentary Petrology, v. 40, p. 888-897. Davis, R. A., Jr., 1985. Coastal morphodynamics: Egmont Key to Anclote Key field trip log, IN: Davis, R. A., Hine, A. c., and Belknap, D. F., (eds.), Geology of the barrier island and marsh-dominated coast, west-central Florida: Guidebook for The Geological Society of America Annual Meeting, Orlando, Florida, 119 p. Davis, R. A Jr., 1987. Morphodynamics of the West-Central Florida barrier system: the delicate balance between wave-and tide-domination, IN: Coastal Lowlands, Geology and Geotechnology, Kluwer Academic Publishers, Netherlands, p. 225-235. Davis, R. A., Jr., 1989. Management of drumstick barrier islands: Proceedings of the 6th Symposium on Coastal and Ocean Management, American Society of Civil Engineers, New York.

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Davis, R. A., Jr., and Andronaco, M., 1987. Hurricane effects and post-storm recovery, Pinellas County, Florida (1985-1986): Coastal Sediments '77, American society of civil Engineers, New York, p. 1023-1036. Davis, R. A., Jr., and Hayes, M. o., 1984. What is a wavedominated coast?: Marine Geology, v. 60, p. 313-329. 89 Davis, R. A., Jr., and Hine, A. c., 1989. Quaternary geology and sedimentology of the barrier island and marshy coast, West-Central Florida, U.S.A.: American Geophysical Union, Washington, 38 p. Davis, R. A., Jr., and Kuhn, B. J 1985. Origin and development of Anclote Key, West-peninsular Florida: Marine Geology, v. 63, p. 153-172. Dean, R. G., 1991. Equilibrium beach profiles: Characteristics and applications: Journal of Coastal Research, v. 7, p. 53-84. Dorjes, J., Frey, R. w., and Howard, J. D., 1986. origins of, and mechanisms for, mollusk shell accumulations on Georgia Beaches: Senckenbergiana Maritima, v. 18, p. 1-43. Driscoll, E. G., 1967. Experimental field study of shell abrasion: Journal of Sedimentary Petrology, v. 37, p. 1117-1123. Driscoll, E. G 1970. Selective bivalve shell destruction in marine environments, a field study: Journal of Sedimentary Petrology, v. 40, p. 898-905. Dubois, R. N., 1989. Seasonal variation of mid-foreshore sediments at a Delaware Beach: Sedimentary Geology, v. 61, p. 37-47. Duncan, J. R., Jr., 1964. The effects of water table and tide cycle on swash-backwash sediment distribution and beach profile development: Marine Geology, v. 2, p. 186-197. Evans, M. w., Hine, A. c., Belknap, D. F., and Davis, R. A., 1985. Bedrock control on barrier island development, Pinellas county, Florida: Marine Geology, v. 63, p. 263-283. Folk, R. L., and Robles, R., 1964. Carbonate sands of Isla Perez, Alacran Reef Complex, Yucatan: Journal of Geology, v. 72, p. 255-292.

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90 Force, L. M., 1969. Calcium carbonate size distribution on the west Florida shelf and experimental studies on the microarchitectural control of skeletal breakdown: Journal of Sedimentary Petrology, v. 39, p. 902-934. Fox, w. T., and Davis, R A., Jr. 1976. Weather pattern and coastal processes, In: Davis, R. A., Jr. and Ethington, R. L. (eds.), Beach and Nearshore Sedimentation, Society of Economic Paleontologists and Mineralogists Special Publication No. 24, p. 1-23. Frey, R. w., 1988. Fair-and four-weather shell accumulations on a Georgia Beach: Palaios, v. 3, p. 561-576. Gibbs, R. J., Matthews, M. D., and Link, D. A., 1971. The relationship between sphere size and settling velocity: Journal of Sedimentary Petrology, v. 41, p. 7-18. Gorsline, D. s., 1966. Dynamic characteristics of West Florida Gulf Coast Beaches: Marine Geology, v. 4, p. 187-206. Graf, w. H., 1971. Hydraulics of sediment transport: McGraw-Hill Book Co., New York, 513 p. Hallermeier, R. J., 1981. Terminal settling velocity of commonly occurring sand grains: Sedimentology, v. 28, p. 859-865. Hampton, M. A., 1979. Buoyancy in debris flows: Journal of Sedimentary Petrology, v. 49, p. 743-758. Hand, B. M., 1967. Differentiation of beach and dune sands, using settling velocities of light and heavy minerals: Journal of Sedimentary Geology, v. 37, p. 514-520. Hayes, M. o., 1972. Forms of sediment accumulation in the beach zone, IN: Waves on beaches and resulting sediment transport, Academic Press, New York, p. 297-356. Hayes, M. o., 1979. Barrier island morphology as a function of tidal and wave regime, IN: Leatherman, s P., (ed.), Barrier Islands, Academic Press, New York, 325 p. Herbers, T. H. c., and Guza, R. T., 1989. Estimation of radiation stresses from slope data array: Journal of Geophysical Research, v. 94, p. 2099-2104.

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91 Herrygers, R. F., 1990. Effect of shell on nourishment performance, Redington Beach, Pinellas County, Florida, University of South Florida, unpublished M.S. thesis, 119 p. Hogue, R.C., 1991. Time-series investigation of sediments, Pinellas County, Florida, University of South Florida, unpublished master's thesis, 160 p. Howard, J. D., and Reineck, H., 1981. Depositional facies of high-energy beach to offshore sequences: comparison with low-energy sequences: American Association of Petroleum Geologists Bulletin, v. 65, p. 807-830. Inman, D. L., and Filloux, J., 1960. Beach cycles related to tide level and local wind wave regime: Journal of Geology, v. 68, p. 255-232. Inman, D. L., Ewing, D. c., and Corliss, J. B 1966. Coastal sand dunes of Guerrero Negro, Baja California, Mexico: Geological Society of America Bulletin, v. 77, p. 787-802. Komar, P. D., 1976. Beach processes and sedimentation: Prentice-Hall Inc., Englewood Cliffs, New Jersey, 429p. Komar, P. D., and Reimers, c. E., 1978. Grain shape effects on settling rates: Journal of Geology, v. 86, p. 193209. Krumbein, w. c., 1941. Measurement and geological significance of shape and roundness of sedimentary particles: Journal of Sedimentary Petrology, v. 11, p. 64-72. Kuenen, Ph. H., 1968. Settling convection and grain-size analysis: Journal of Sedimentary Petrology, v. 38, p. 817-831. Kuick, A. J., van Vledder, G. Ph. and Holthuijsen, L. H., 1988. A method for the routine analysis of pitch-and roll buoy wave data: Journal of Physical Oceanography, v. 18, p. 1020-1034. Lotus Development Corporation, 1991. Lotus 1-2-3 Release 2.3, Cambridge, MA. Maiklem, w. R., 1968. The Capricorn Reef complex, Great Barrier Reef, Australia: Journal of Sedimentary Petrology, v. 38, p. 785-798.

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92 Matthews, M. D., 1991. The effect of grain shape and density on size measurement, IN: Syvitski, J. P. M., (ed.), Principles, methods, and application of particle size analysis, Cambridge University Press, New York, 368p. May, J P., 1981. A proposed standard parameter for settling tube analysis of sediments: Journal of Sedimentary Petrology, v. 51, p. 607-610. McKenna, K., 1990. Time-series analysis of beach morphology, Pinellas County, Florida: University of South Florida unpublished M.S. thesis, 149 p. Mehta, A. J Jieh Lee, A. H., and Christensen, B. A., 1980. Fall velocity of shells as coastal sediment: Journal of the Hydraulic Division, v. 106, p. 1727-1744. Menard, H. w and Boucot, A. J., 1951. Experiments on the movement of shells by water: American Journal of Science, v. 249, p. 131-151. Middleton, G. v., 1976. Hydraulic interpretation of sand size distributions: Journal of Geology, v. 84, p. 405426. Middleton, G. v., and Southard, J. B 1978. Mechanics of sediment movement: Society of Economic Paleontologists and Mineralogists, Binghamton, New York, 246 p. Miller, R. L and Zeigler, J. M., 1959. A study of the relation between dynamics and sediment pattern in the zone of shoaling wave, breaker, and foreshore: Ecologae Geologicae, v. 51, p. 542-551. Mitchell-Tapping, H. J., 1977. Abrasion rates of certain marine shells and corals: Florida Scientist, v. 43, p. 279-284. Moss, A. J., 1972. Bed-load sediments: Sedimentology, v. 18, p. 159-219. Muir wood, A.M., 1969. Coastal hydraulics: Gordon and Breach Science Publishers, New York, 187 p Nagle, J. s., 1964. Differential sorting of shells in the swash zone: Biological Bulletin, v. 127, p. 353. Nagle, J. s., 1967. Wave and current orientation of shells: Journal of Sedimentary Petrology, v. 37, p. 1124-1138.

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93 Payne, L. E., and Pell, W. H., 1960. The stokes flow problem for a class of axially symmetric bodies: Journal of Fluid Mechanics, v. 7, p. 529-549. Reed, W. E., LeFever, R., Moir, G. J., 1975. Depositional environment interpretation from settling-velocity {Psi) distributions: Geological Society of American Bulletin, v. 86, p. 1321-1328. Rosen, D. s., 1976. Beach and nearshore sedimentation of Caladesi Island state Park, Pinellas county, Florida: University of South Florida unpublished M.S. thesis, 114p. Sallenger, A. H., Jr., 1979. Beach-cusp formation: Marine Geology, v. 29, p. 23-37. Scott, T. M., 1988. The lithostratigraphy of the Hawthorn Group {Miocene) of Florida: Florida Geological Survey, Tallahassee, Florida, Bulletin 59, 148 p. Sneed, E. D., and Folk, R. L., 1958. Pebbles in the lower Colorado River, Texas: a study in particle morphogenesis: Journal of Geology, v. 66, p. 114-150. Sonu, c. J., 1972. Field observation of nearshore circulation and meandering currents: Journal of Geophysical Research, v. 77, p. 3232-3247. Stapor, F. w., and Matthews, T. D., 1980. C-14 chronology of Holocene barrier islands, Lee County, Florida, shorelines past and present: Department of Geology, Florida State University, 45 p. Syvitski, J. P. M., Asprey, K. w., and Clattenburg, D. A., 1991. Principles, design, and calibration of settling tubes, IN: Syvitski, J. P.M., (ed.), Principles, methods, and application of particle size analysis: Cambridge University Press, New York, 368p. Taira, A., and Scholle, P. A., 1977. Design and calibration of a photo-extinction settling tube for grain size analysis, Journal of Sedimentary Petrology, v. 47, p. 1347-1360. Tanner, w. F., 1960. Florida coastal classification: Gulf Coast Geological Society Transactions, v. 10, p. 259-266.

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Upchurch, s B., 1970. Sedimentation on the Bermuda Platform: National Oceanic and Atmospheric Administration, Department of Commerce, Detroit, Michigan, 172p. U.S. Army, 1989. Beach erosion control project, Pinellas County Florida: Plans for Beach Nourishment 2nd Contract (Advance Copy), Jacksonville District Corps. of Engineers, 24p. Vanoni, v. A., 1975. Sedimentation Engineering: American Society of Civil Engineers, New York, 745 p. Williams, G. P., 1966. Particle roundness and surface texture effects on fall velocity: Journal of Sedimentary Petrology, v. 36, p. 255-259. Wright, L D., and Short, A. D., 1984. Morphodynamic variability of surf zones and beaches: a synthesis: Marine Geology, v. 56, p 93-118. 94 Wright, R., and Thornberg, s. M., 1988. Sedidat: a BASIC program for the collection and statistical analysis of particle settling velocity data: Computers and Geosciences, v. 14, p. 55-81.

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95 APPEND I CBS

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1900 ''--2 ,-... .! 1700 k --11 g 1500 -lo 0 1300 -. 1100 6 :I: 900 700 I 0 10 20 30 40 50 60 70 80 90 100 Distance from monument (meters) Figure 32. Serial plot of beach profiles from spring tide, low-energy tidalcycle study at R-75. t til I 110 > tO tO l:%j z 0 H >< ..... tJj l:%j > () :I: tO 0 tor:! H &; (/) 10 0\

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1900 t--... -2 ........ g 1700 k -1 I g 1500 l= _.o v 1300 E--4 1100 .... ::s 0 900 v N 700 I I 0 10 20 30 40 50 60 70 80 90 100 Distance from monument (meters) Figure 33. Serial plot of beach profiles from neap tide, low-energy tidalcycle study at R-75. ] I I 110 > 10 10 t%j z 0 H >:: ..... -0 0 rt ..... ,::: (1) 0. \0 -....1

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1530 1330 0 1130 930 730 0 10 20 30 40 50 60 70 80 Distance from monument (meters) 90 100 2 g 1 m 0 110 Figure 34. Serial plot of beach profiles from spring tide, high-energy tidalcycle study at R-75. > 'tl z 0 H :>< ....... 0 0 ::s rt 1-' ::s ,:::: (I) p, ...... C.

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APPENDIX 1. (continued) 99 BEACH PROFILE CHARACTERISTICS Spring tide, low-energy tidal-cycle study (June 26, 1991) Time Beach Slope Swash Width Foreshore Wi dth Percent (24 Hour} (degrees} (meters} (meters} Swash 700 9 72 4.50 10 98 41.0 800 8 25 6.50 11. 28 57 6 900 7 65 7.50 10.67 70.3 1000 8 43 8.75 10.98 79 7 1100 5 55 9 00 10.98 82.0 1200 5.51 9 25 11.28 82 0 1300 5 78 8 25 11.28 73 1 1400 7 43 6.86 1 1.59 59.2 1500 10 36 5 00 11.59 43.2 1600 6.67 3.75 12 80 29 3 1700 5 .91 4 00 14 63 27 3 1800 5.57 4.00 15 24 26 2 Neap tide, low-energy t idal-cycle study (September 3 1991) Time Beach Slope Swash W i dth Foreshore Width Percent (24 Hour} (degrees} {meters} (meters} Swash 730 5 .81 9.50 2.79 103.8 830 5 60 8.70 2 97 89.2 930 6.11 7.00 3.35 63 8 1030 5.89 6 75 3 35 61. 5 1130 6.01 5.50 3 .81 44 0 1230 6.84 5 10 3 90 39.8 1330 7 69 4.50 4 02 34.1 1430 6.08 4.60 4 09 34.3 1530 7 55 5 00 4 46 34.2 1630 7 35 4 27 4 37 29 8 1730 5 36 5 49 4 09 40.9 1830 6 .31 5.75 4 37 40.1 1930 6.71 7 50 4 .46 51.3 2030 5 19 6 00 4.18 43 7 Table 6. Characteristics of beach profiles used as input for Pearson's correlation matrix from the spring tide, low-energy study and the neap tide, low-energy study.

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APPENDIX 1. {continued) 100 BEACH PROFILE CHARACTERISTICS Spring tide high-energy tidal-cycle study (February 6 1992) Time Beach Slope Swash Width Foreshore Width Percent {24 Hour} {degrees} {meters} {meters} Swash 730 6 68 15 90 24 5 64 8 830 6.77 16. 00 24.4 65 5 930 6 94 19 10 23.5 81.1 1030 6.48 21.60 21. 6 100 0 1130 6.91 23.00 20 8 110.7 1230 6.33 25. 00 21. 4 116 7 1330 6 07 24. 00 22 5 106 6 1430 5.54 23. 00 23 3 98 6 1530 5 .31 20.80 24.0 86 7 1630 1.33 17. 00 25 0 68 0 1730 1.29 16.00 27 0 59 3 1830 1.26 13.00 26 0 50 0 1930 1.16 16. 00 25 0 64 0 Table 7. Characteristics of beach profiles used as input for Pearson's correlation matrix from the spring tide, high-energy study

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Spring tide low-energy tidal-cycle study (June 26 1991) Lower swash samol --700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 O.Ochi 0 .00 0 00 0 .00 0 .00 0 .00 0 00 0 .00 0.00 0 .00 0.00 0.00 0 .5chi 0 00 0 .00 0 .00 0 .00 0 .00 0 00 0.00 0 00 0 .00 0 .00 0.00 1 0 chi 0 00 0 .00 0 .00 0 .00 0 .00 0 00 0 .00 0 00 0 .00 0 .00 0 .00 1.5 chi 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0.00 0.00 2.0chi 0 .00 0 .00 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 00 0 00 2.5 chi 1 .50 0 .70 0.00 0 .00 0.00 0 .00 0 .80 0 .40 0 .00 0 .00 0 .30 3 .0chi 1 .00 2 70 0 00 0 .00 0 .00 0.00 0 .00 0.60 7.80 0 80 0 .10 3 5 chi 8.10 13.70 0.00 0 .00 0 .00 0 00 0 .00 0.80 11.00 0 .50 0 .90 4.0chi 10.40 12.70 0 .00 0 .00 0 .00 0 00 0 .30 0 .10 0 90 1 .70 0 .90 4.5 chi 11.40 10.30 0 .00 0 .00 0 .00 0 .00 0 .20 1.20 0 .50 0 .40 3 .00 5.0chi 14.20 13.40 0 .50 10. 20 9 .30 0.80 6.40 9.20 6 .00 3 .30 5.80 5 .5chi 25.60 31.10 0 20 32.70 31.90 0 .00 10.70 43.60 29.70 33 00 34 80 6 .0chi 18. 50 10. 30 0.20 18.30 32.30 0 50 7 .30 24.30 23.70 44.70 42.10 6.5 chi 7 .30 1.90 0 .80 4 .00 5 .80 0 00 2 .70 5 .90 4 50 10. 50 9 60 7.0chi 0 .20 1.30 0 .00 1 .60 1 .90 0.50 0.50 1.20 1 50 0 .90 1.10 7 .5chi 0 .50 0 .50 0 .30 1 .10 0 .30 0 .20 0 .60 0 .90 1.40 0 .70 0 30 8.0chi 0.00 0.30 0.60 0.00 0 .00 0.00 0 .50 0 .00 0 .00 0 .80 0 .10 ------------Table 8. Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the spring tide, low-energy study. 24 hour times are indicated. 1800 0 .00 0 .00 0 .00 0 .00 0 .00 0 20 1.20 0 .50 0 .40 1 .701 2.30 28.70 52.90 8 20 2 .30 0 .10 0 .00 > "d "d tr:l z 0 H >< I\) t-.j(') (')0 8H HC/l 08 oH 88 :;x:H C/lt-.j tr:lo H C/lC/l 0 .... 0 ....

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Spring tide low-energy tidal-cycle study (June 26, 1991) Uooer swash samol -700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 0.0 chi 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.5 chi 0 .00 0 .00 0.00 0.00 0 .00 0 00 0 .00 0 .00 0.00 0 .00 0.00 1.0 chi 0 .00 0 00 0.00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 1.5 chi 0.00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 2 0 chi 0.00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0.00 2.5 chi 0.00 0.00 0 .00 0 .00 0 .00 0.30 0 .60 0 .00 0 .50 0.30 1.10 3.0 chi 0 .00 0 .00 0.00 0.00 0.50 12.10 2 .80 0 .00 1 10 0.30 2.60 3.5chi 0 .00 0 .00 0.00 0.00 0.30 0.30 11.30 4.30 12.00 1 .10 0 .30 4.0chl 0 .00 0.00 0 .00 0 .00 1 .10 2 .60 0 .30 5.20 13.90 2 .00 1.80 4.5chi 0 .00 0 .00 0 .00 0.00 0.50 0.80 0.90 0.90 10.90 1.40 1.80 5.0 chi 11.20 9.30 0.20 6.90 3.60 6.80 12.30 9 .70 13. 20 5.70 4 .00 5 .5chi 29 .70 33.00 0 .40 19 .60 11.20 17. 90 27.10 36.50 30.00 40. 30 41.30 6.0chl 20 .50 20 .00 0.20 8 .40 7.40 10.00 14.50 28.60 13.60 37.70 38.80 6 5 chi 4.50 4 30 0 .10 2 50 1.40 3.10 3.20 5 .80 2.20 8 80 5 50 7 0 chi 0 50 0 .00 0 .50 0 .70 0 .80 0 .60 1 .20 1 .70 0.00 0 60 0 70 7 .5chi 0 00 0.40 0 .10 0.00 0.00 0.20 0.40 0.00 0 20 0.80 0.00 8.0chi 0.40 0.50 0 20 0 70 0.00 0 .20 0 .10 0.00 0 70 0 00 0.00 Table 9. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the spring tide, low-energy study. 24 hour times are indicated. 1800 0 .00 0 .00 0.00 0.00 0.00 0.50 0 .80 0 .90 0.90 0.70 4 90 32.10 46.80 8 80 0.40 1.90 0 00 > "t1 "t1 l:%j z 0 H >< I\) 0 0 ::;, rt ...... ::;, It) 0. .... 0 I\)

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Neap tide, low-energy tidal-cycle study (September 3, 1991) Lower swash samol ------------r--700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 0.0 chi 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0.00 0.5 chi 0.00 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 0 .00 0.00 1 0 chi 0 00 0 .00 0.00 0 .00 0 .00 0 00 0 .00 0.00 0.00 0 00 0 .00 0.00 1.5 chi 0.00 0.00 0.00 0 .00 0 .00 0 00 0 .00 0.00 0 .00 0 00 0.00 0 00 2 0 chi 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.5 chi 1 .70 0 .10 1.00 0 .60 0.00 0 .20 0.30 0 .00 0 .00 0.30 0.10 0 .20 3 .0chi 30.50 22.30 22.40 7.50 1.40 3 .10 0 .80 0.80 1 .20 1.40 2.60 5 .00 3 .5chi 46.50 51.00 56.80 33.30 10. 60 13. 30 1 .70 1 .80 2.00 6 .80 18.50 11. 20 4.0 chi 14.60 16.50 14.90 20.70 13.10 14.40 3.80 2 .20 1.70 6 .30 1 2 .70 13 80 4.5chi 1 .10 4.70 1.50 9.50 15.00 11.70 5.60 6 .70 2.80 5.60 10.60 10.00 5.0 chi 1.40 1 .10 0 90 8 .90 18.50 17.50 9 .10 9 .60 6 .80 10.10 17.20 17. 20 5.5 chi 1 .30 0 .90 0 .80 9 40 24.60 19.70 36.80 32.80 32.10 33.60 19.90 25 50 6.0chi 0 .10 0 .00 0 .00 6 10 11.40 14.20 30.30 31.60 40.40 24.60 11.90 10.10 6.5chi 0 .00 1.20 0.20 1 .60 3.00 2 .90 7 .80 9 .90 10.10 6 60 3 60 4.10 7.0chi 0.90 0 .60 0 40 0 .30 0 .50 1.30 1.70 2.90 0 .80 2 .70 0 .80 1.10 7 .5chi 0 .00 0.30 0 .30 0 .70 0.80 0 .60 0.50 0 .00 0 .80 0.30 0.60 0 80 8 .0chi 1.30 0.00 0 .00 0.50 0.50 0.10 0.40 1 .50 0 .00 1.10 0 .30 0 00 Table 10. Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the neap tide, low-energy study. 24 hour times are indicated. 1900 0 .00 0 .00 0.00 0 .00 0 .00 0 .30 16.70 39.70 18.00 6.60 4 .60 5 .90 4.10 0 .60 2.70 0 .00 0 .00 2000 0.00 0 .00 0.00 0 .00 0.00 1.40 22.00 53.00' 17.40 1.90 0 .50 1.20 0.00 0 00 0 00 0 00 0 00 "d "d l:xj z 0 H >< !\.) 0 0 ::s rt 1-' (I) 0. 0 w

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Neap tide, low-energy tidal-cycle study (September 3, 1991) Uooer swash samol -l"""r-------r---700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 O.Ochi 0.00 0.00 0.00 0.00 0 00 0.00 0 .00 0 00 0.00 0.00 0.00 0.00 0.5 chi 0 .00 0 00 0.00 0.00 0 00 0 .00 0 00 0.00 0 00 0.00 0.00 0 00 1.0 chi 0 00 0 .00 0 00 0.00 0.00 0 .00 0 00 0.00 0 00 0.00 0.00 0 00 1 5 chi 0 00 0.00 0.00 0.00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 00 2.0chi 0 00 0 .00 0.00 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 0 .00 0 00 2 5 chi 0 .40 0.00 0.00 0.00 0 .30 0.30 0.10 0.10 0.10 0.10 0 .00 0.30 3.0chi 10.50 11.60 3 .40 3 .40 3.10 0.40 0.60 0 60 0.60 0.60 1.20 2.40 3.5 chi 58.80 49.40 19.00 15.70 15.20 7 .30 2 .80 2 .80 2.80 2 .80 1.80 11.40 4 0 chi 18.70 23 60 18.20 14.40 14.80 7.90 5.70 5.70 5.70 5 .70 0 .00 9 30 4 .5chi 5 .40 5.70 14. 60 11. 20 11.90 13.00 7.60 7 60 7.60 7.60 2 .30 5 80 5.0chi 1 .10 3.00 14.20 11. 80 16.60 18.80 15.10 15.10 15.10 15.10 9.20 9.40 5 5 chi 1 .50 2 .10 15.80 26 20 19.90 26 .10 41.40 41.40 41.40 41.40 27.00 30.10 6 .0chi 0 .80 1 .70 8.10 10. 90 11.80 16.10 19.30 19.30 19.30 19.30 38.90 21.10 6 5 chi 0.10 0.40 3.00 3.30 3.40 4.10 4.70 4 70 4.70 4.70 13.40 7.20 7.0chi 0 00 0.80 0.70 1.60 1.50 2.50 1.20 1.20 1.20 1.20 2.10 1 20 7.5chi 0.00 0.80 0.00 0.00 0.20 0.50 0.50 0.50 0.50 0.50 0.70 1.10 8 .0chl 0 .00 0 00 0.20 0.00 0.50 0.00 0.60 0.60 0.60 0 .60 0 60 0 00 Table 11. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the neap tide, low-energy study. 24 hour times are indicated. 1900 2000 0 00 0.00 0.00 0 .00 0.00 0 .00 0.00 0.00 0.00 0 .00 0.80 0.00 33.30 25.80 45.30 50. 90 12.30 14. 90 2.30 2 90 1.70 1 .80 1 50 0 .80 0 .80 0 50 0 00 0.00 0.00 0.30 1 30 0.00 0 00 0.40 > I'd z 0 H >< t\) 0 0 ::s rt ,.... s (I) p. .... 0 ol:ao

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Spring tide, high-energy tidal-cycle study (February 6, 1992) Lower swash samol --730 830 930 1030 1130 1230 1330 1430 1530 1630 1730 1830 O.Ochi 0 .00 0 .00 0.00 0 .00 0 .00 0.00 0.00 0.00 0.00 0 .00 0 .00 0 .00 0.5chi 0 .00 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 1.0 chi 0.00 0.00 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 1.5 chi 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0.00 0.00 0.00 0 .00 2 .0chi 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0.00 0.00 0 .00 0.00 2.5chi 1 .90 0.00 0 .00 0 50 0 .80 0 .00 0 .00 1 .40 0 .00 0.00 0 .50 1 .20 3 .0chi 11. 50 6.30 15.50 23.80 20.00 24. 80 15 .20 24. 60 9 .50 21.90 7.70 7.80 3.5chi 35.50 48 .10 53.80 56 .00 62.60 50.30 60.70 56.00 64.30 49.50 33.30 25.80 4.0chi 24.00 31. 40 18 20 14.60 9 00 14.60 15 .00 7.80 14.90 20.90 29.50 43.20 4.5chi 13.50 8 .60 3.50 0.00 1.40 3 .30 0 .00 0.00 4 .30 4 .10 10.80 13. 40 5.0chi 3.70 1 20 0 .40 0 .00 0.90 0 .70 4.40 0 .00 1.00 1.10 7.10 3.70 5 .5chi 1 .90 0 50 2.10 1 10 1 .30 0 .00 0.00 0.70 0 .00 0 .00 5.90 1 40 6 .0chi 2 .00 1 .00 0.20 1 .90 0.00 0 .00 0 .00 0.00 0 .60 0 20 0 .30 0 .30 6.5 chi 0 .90 0 .00 0.00 0 .00 0.00 0.00 0 .00 1.20 0 .00 0 .20 2 .60 0 .50 7 .0chi 0.00 0 .30 0.90 0.00 0 .00 0.00 0 .00 0 .00 0 20 0.10 0.00 1 .00 7 .5chi 2 .70 0 .70 0 00 0 .00 0 .00 0.60 0 .00 1 .10 0.90 0 .00 0 .00 0 .00 8.0chi 0 .00 1 10 1 00 0 .00 0 .00 0.00 0.00 0.00 1.60 0.10 0 .00 0 .00 Table 1 2 Chi weight-percent distributions for the sand fraction of the lower swash sediment samples from the spring tide, high-energy study. 24 hour times are indicated. 1930 0 .00 0 .00 0 .00 0 .00 0.00 1.00 9 .30 33.60 24.40 13.60 8 .50 4 .50 0 .00 0 .00 3.70 0.00 0 .00 > 'U 'U tr:l z 0 H :>< N ....... C'l 0 ::s rt 1-' s 10 p., ..... 0 U1

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Spring tide high -energy tidal-cycle study (February 6, 1992) Uooer swash samol -730 830 930 1030 1130 1230 1330 1430 1530 1630 1730 O .Ochi 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 00 0 .00 0 .00 0 .5chi 0 .00 0.00 0.00 0 00 0 .00 0.00 0 .00 0.00 0 00 0.00 0 .00 1 0 chi 0 .00 0 .00 0 .00 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 1 5 chi 0.00 0 .00 0 .00 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 2.0 chi 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 2 .5chl 2 20 1.40 0.40 1.00 0.40 0 .00 0.00 0.00 0 .00 1 .10 0 .00 3.0chi 3.30 8 00 4 9 31. 70 15.00 20. 70 9 .90 8 .40 10.00 4.00 1.40 3 .5chi 20.60 24.10 19 .60 50 20 53 .90 52. 00 52.90 50 00 39.70 25.80 8 50 4 0 chi 26.40 35.10 21.80 10. 20 20.00 17.00 23.20 26 .20 26.70 28.10 12.20 4 5 chi 16.20 15.50 25.10 2 30 4 90 4 .10 4 .10 9.00 8 .80 14.10 16.50 5.0 chi 18.40 5 .30 16.10 0.00 1 20 1.40 3 .60 0 .00 3 .10 12.30 20 .70 5 5 chi 4 .70 2 .00 7 .10 0 .00 1 20 0 .40 0 .90 1 .20 5 .60 8 .00 27 .10 6.0 chi 1.50 2 .90 0.00 0.00 0 00 0 .00 1 .30 1 .30 2.20 1.30 8 .00 6 5 chi 2.20 0.00 0 .70 0 .00 0 .60 0 .60 0 .00 0 .00 0 .00 0 .00 1.60 7 0 chi 0.00 0 .00 0 80 0 .80 1.30 0 .00 1 20 2 .20 0.00 3 .10 0 .30 7.5 chi 1 .50 0 .00 0 .00 0.00 0 00 0.00 0 .50 0 .00 0 .00 0 .00 0.00 8 0 chi 0.00 0 .00 2 50 0 .00 0 .20 0.50 0 .90 0 .00 1 .70 1 .10 0 .00 Table 13. Chi weight-percent distributions for the sand fraction of the upper swash sediment samples from the spring tide, high-energy study. 24 hour times are indicated. 1830 0 .00 0.00 0 00 0 .00 0 .00 0 .40 0.00 10. 50 18.90 17.70 26.90 14.10 3 50 1 .80 2 .30 0 .00 0 .00 1930 0 .00 0.00 0 .00 0 .00 0.00 0.50 0 .90 2 .90 10.20 15. 20 17. 70 1-34.10 c 12.10 2.40 ; 2 .70! 0 00 i 0 .00 I .... 0 0\

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C i rcular whole Circular whole Circular shell Whole Elongate shell Phosphatized Decomposed Phosphate Uth ic bivalves bivalves (sm) fraaments Ar1 "0 "0 t%j z 0 H X w Cll() H::X: NH CllH "':;d t%JH ()1-3 Cllo Cllz t%:1(/l Clll'%j 0 :;d G') t-4 1-' 0 "-1

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APPENDIX 3. (continued) 108 Spring tide, low-energy tidal-cycle study {June 26, 1991) Lower swash samples PHI CHI 700 800 900 1000 1100 1200 Lithic fragments -3.0 1 58 0 00 0 .00 0 .00 0 .00 0 .00 0.00 Phosphate -3. 0 1 .61 0 00 0 .00 0 .00 0 .00 0.00 0 .00 Phosphate -2.5 1 66 0 00 0 00 0 97 0 .00 0 .00 0 .00 Lithic fragments -2. 5 1 73 0 .00 0 .00 0 .77 0 .00 0 .00 0 .00 Lithic fragments -2. 0 1.76 0 00 0 .00 0 .19 0 .00 0 .00 0 .00 Phosphate -3. 5 1 82 0 00 0 .00 0 00 0 .00 0 .00 2 56 Phosphate -2. 0 1 83 0 .00 0 .00 0 .00 0 .00 0 00 0.15 Lithic fragments 1 5 1 98 0 .00 0 .00 0 .38 0.00 0.00 0 .00 Equant whole bivalves -3. 5 2 .06 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 Elongate shell fragments -1. 5 2 .11 0.00 0 05 1 .14 0 .00 0 .00 0 26 E longate shell fragments -3. 0 2 .26 0 .00 0 00 0 .60 1.09 0 .00 1 .79 Equant shell fragments -3. 0 2 28 0 .38 0 47 1 .81 0 .00 0 .00 1 .08 Equant shell fragments -2. 5 2.35 0 .00 0 .30 1 74 0.00 0.00 0 .91 E l ongate shell fragments -3. 0 2 38 0 .00 0 00 1 .21 0 .00 0 .00 1 .51 Mineralized shells -2. 5 2 .41 0 .00 0 00 0 39 0 .00 0 00 1 .35 Decomposed shells -2. 0 2 .41 0.24 0 .20 2 .41 0 .21 0 .00 1 .88 M i neralized shells -2. 5 2 43 0 .00 0 .00 0 00 0 .00 0 .00 0.00 Whole Arks -3. 0 2 47 0 .00 0 00 0 .00 0 .00 0 00 0 .50 Decomposed shells -3. 0 2 48 0 .00 0 00 1 .21 0 .00 0 .00 0 .50 Equant shell fragments -3. 0 2 .53 0 .00 0.00 0 .60 0 .00 0.00 1.79 Equant whole bivalves {sm) -2. 5 2 55 0 .00 0 00 0 .00 0 .00 0 .00 0 .00 Mineralized shells -2. 0 2 56 0 .00 0 20 3 .38 0 .00 0 .17 1 .50 Whole Arks -3. 0 2 .59 0 .00 0.00 0 .60 0 .00 0 .00 0 .00 Decomposed shells -2. 0 2 .60 0 .00 0 .20 0 .77 0 .00 0.00 1.50 Equant whole bivalves -2. 5 2 64 0 .00 0.00 0 .00 0.00 0 .00 0.85 Elongate fragments 2 0 2 65 0 .00 0 20 0 48 0 .00 0.00 0.75 Mineralized shells -2. 5 2 69 0 .00 0 00 0 .00 0 .00 0.00 0.27 Whole Arks -1.5 2 .79 0 .09 0 39 2 .85 0 32 0 .12 2 .34 Equant shell fragments -1. 5 2 .81 0 .00 0 44 3 .80 0 .19 0.00 1 .95 Decomposed shells -2. 0 2 86 0 .00 0 00 0 48 0 .00 0 .00 0 .60 Coquinas -1. 5 2 87 0 .00 0 85 4 .18 0 .43 0 .00 3 .25 Equant whole bivalves -1. 5 2 .89 0 .00 0 00 1 .90 0 .00 0 .00 0 65 Equant whole bivalves -3. 0 2 94 0 .00 0 00 0 .00 0.00 0 .00 0 .00 Whole Arks -1. 5 2 99 0 .00 0 65 3 .80 0 .25 0 .00 3 .25 Equant whol e b i valves -2. 0 2. 99 0.00 0 .00 1 .93 0 .00 0 .00 1 .13 Whole Arks -1. 5 3 .07 0 .00 0 .21 0 .95 0 08 0 .00 1 .30 Table 15. Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, low-energy tidal study.

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APPENDIX 3 (continued) 109 Spring t ide, low-energy tidal-cycle study L h I owerswas samples PHI CHI 1300 1400 1500 1600 1700 1800 Lithic fragments -3. 0 1 .58 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 Phosphate -3. 0 1 .61 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -2.5 1 .66 0 .16 0 .00 0 .00 0 .00 0 .00 0 .00 Lithic fragments -2. 5 1 .73 0 .47 0 .00 0 .00 0 .00 0 .00 0 .00 Lithic fragments 2 0 1 .76 0.19 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -3. 5 1 .82 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate 2 0 1 .83 0 .08 0 .00 0 .00 0 .00 0 .00 0 .00 Lithic fragments -1. 5 1 .98 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Equant whole bivalves -3. 5 2 .06 3 .04 0 .00 0.00 0 .00 0.00 0 .00 Elongate shell fragments -1.5 2 .11 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Elongate shell fragments -3. 0 2 .26 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 Equant shell fragments -3. 0 2 .28 0 .22 0 .00 0 .00 0 .00 0 .00 0 .00 Equant she ll fragments -2. 5 2 .35 0 .39 0 .00 0 .00 0.00 0 .00 0 .00 Elonga t e shell fragments -3. 0 2 .38 0 .45 0 .00 0 .00 0.00 0 .00 0 .00 Mineralized shells -2. 5 2 .41 0.65 0 .00 0.00 0 .00 0 .06 0 .00 Decomposed shells -2. 0 2 4 1 0 .49 0 .00 0 .00 0 .00 0 .00 0 .00 Mi neralized shells -2. 5 2 .43 0.16 0 .00 0 .00 0 .00 0 .00 0 .00 Whole Arks -3. 0 2 .47 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Decomposed shells -3. 0 2 .48 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Equan t shell fragments -3.0 2.53 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Equant whole bivalves (sm) -2. 5 2.55 0 31 0 .00 0 .00 0 .00 0 .00 0 .00 Mineralized shells -2. 0 2 .56 1 .03 0 .00 0 .00 0 .00 0 .00 0 .00 Whole A r ks -3. 0 2 .59 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Decomposed shells -2.0 2 .60 0 .95 0 .00 0 .00 0 .00 0 .00 0.00 Equan t whole bivalves -2.5 2 .64 0 .00 0 .00 0.00 0 .00 0.00 0 .00 Elongate fragments -2. 0 2 .65 0 .38 0 .00 0.00 0 .00 0.00 0 .00 Mineralized shells -2.5 2.69 0 .47 0.00 0.00 0.00 0 .00 0 .00 Whole Arks -1.5 2 .79 0.00 0 .00 0 .16 0.00 0 .00 0 .00 Equant shell fragments -1.5 2 .81 0 .00 0 .03 0 .00 0 .00 0 .00 0 .00 Decomposed shells -2. 0 2.86 0 .00 0 .00 0.00 0.00 0 .00 0 .00 Coquinas -1. 5 2 .87 0 .00 0 .03 0 .00 0 .03 0 .00 0 .00 Equan t whole bivalves -1. 5 2 .89 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Equant whole bivalves -3. 0 2 .94 0 .22 0 .00 0 .00 0 .00 0 .00 0 .00 Whole Arks -1. 5 2 .99 0 .00 0 .00 0 .08 0 .06 0 .00 0 .00 Equant whole bivalves -2. 0 2.99 0 .68 0 .00 0 .09 0 .00 0 .00 0 .00 Whole Arks -1. 5 3 .07 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Table 15. (cont'd) Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, low-energy tidal study.

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APPENDIX 3. (continued) 110 Spring tide, low-energy tidal-cycle study (June 26 1991) Upperswas h samples PHI CHI 700 800 900 1000 1100 1200 Lithic fragments -3. 0 1.58 0 00 0.00 0 00 0 00 0 00 0 00 Phosphate -3.0 1 .61 0 00 0 00 0 .00 0.00 0 .00 0 00 Phosphate -2. 5 1.66 0 00 0 00 0.00 0.00 0.00 0 00 Lithic fragments -2.5 1.73 0.00 0 00 0.00 0 00 0.00 0.00 Lithic fragments -2. 0 1.76 0 00 0 00 0 42 0 .71 0.29 0 00 Phosphate -2. 0 1 83 0 00 0 00 0 .00 0 00 0 00 0 19 Phosphate -3.5 1.96 0 00 0 00 0 .00 2 73 0 .00 0 .00 Lithic fragments -1. 5 1.98 0 00 0 00 0 .11 0 00 0 .00 0 10 Equant whole bivalves -1. 5 2 .11 0 00 0 53 0 .21 0 54 0 .27 0 00 Elongate shell fragments -3.5 2 13 0 00 0.00 0.00 1 40 0 00 0 00 Elongate shell fragments -3.0 2 26 0 00 0.56 1.89 5.25 0 00 0 00 Equant shell fragments -3.0 2 28 0 00 0 56 1.89 2 25 0 63 0 .45 Equant shell fragments -2. 5 2 35 0 00 0 45 1.29 0.24 0.00 0 53 Elongate shell fragments -3. 0 2.38 0 00 0 00 1 .51 3 75 1.69 0.00 Mineralized shells -2.0 2.41 0 16 0 .71 0 .61 1 78 2 89 0 76 Decomposed shells -2. 5 2.41 0 00 0 00 1 08 0 00 0 .50 0 27 Mineralized shells -2. 5 2.43 0 00 0 00 0 22 0 73 0.88 0 27 Whole Arks -3. 0 2.47 0 00 0 00 0.00 0 75 0.00 0 00 Decomposed shells -3. 0 2.48 0 00 0 00 0.00 1.20 1 90 0.00 Equant shell fragments -3.0 2.53 0 00 0 00 2 27 1 80 0.00 0 00 Equant whole bivalves (sm) -2.5 2.55 0.00 0 00 0 22 0 53 0 43 0 .00 Mineralized shells -2.0 2 56 0 15 1.25 2.00 3 08 5 .35 0.83 -3. 0 2 59 0 00 0 48 0 00 0 00 0 .00 0 .00 Decomposed shells -2.0 2.6 0 15 0 .71 1.21 1 42 1 74 ..., Equant whole bivalves -2. 5 2.64 0.00 0 00 0.43 0 24 0.25 Elongate fragments -2.0 2.65 0.00 0 00 0 30 0 95 0.72 .. o M i neralized shells -2.5 2.69 0.00 0 00 1.08 0 24 0 45 0.00 Whole Arks -1. 5 2.79 0.04 0 88 1 58 2 68 2.04 1 .00 Equant shell fragments -1.5 2.81 0 07 0 97 2.11 2 14 2 72 1.00 Decomposed shells -2.0 2 86 0 00 0 00 0 00 0.95 0 58 0 00 Coquinas -1.5 2 87 0 20 0 88 2 85 2 68 3.39 1 .40 Equant whole bivalves -1. 5 2.89 0 04 0 00 0 85 0 86 1 36 0 40 Equant whol e biva l ves -3. 0 2.94 0 00 0 00 0 00 0.00 0.00 0 00 Whole Arks -1. 5 2.99 0 07 0 88 2 64 1 .61 2 72 1.10 Equant whole bivalves -2. 0 2.99 0 00 0 .17 1 52 2 96 2 .89 0.19 Whole A rks -1.5 3 07 0 04 0 26 0 .21 0 .21 1.09 0 .00 Table 16. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, low-energy tidal study.

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APPENDIX 3. (continued) Spring tide, low-energy tidal cycle study U h I Jpper swas samples Lithic fragments Phosphate Phosphate Lithic fragments Lithic fragments Phosphate Phosphate Lithic fragments Equant whole bivalves Elongate shell fragments Elongate shell fragments Equant shell fragments Equant shell fragments Elongate shell fragments Mineralized shells Decomposed shells Mineralized shells Whole Arks Decomposed shells Equant shell fragments Equant whole bivalves (sm) Mineralized shells Whole Arks Decomposed shells Equant whol e bivalves Elongate fragments Mineralized shells Whole Arks Equant shell fragments Decomposed shells Coquinas Equant whole bivalves Equant whole bivalves Whole Arks Equant whole bivalves Whole Arks Table 16. (cont'd) PHI CHI 1300 1400 1500 1600 1700 1800 -3. 0 1 .58 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 -3.0 1.61 0 .00 0.00 0 .00 0 .00 0.00 0 .00 -2.5 1.66 0 .00 0.00 0 .00 0.00 0.00 0.00 -2. 5 1.73 0 .00 0 .00 0.00 0.00 0 .00 0 .00 -2. 0 1.76 0 .00 0 .00 0 .00 0.00 0.36 0 .00 -2. 0 1.83 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 -3. 5 1 .96 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 1. 5 1 .98 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -1. 5 2 .11 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 5 2 .13 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 0 2 .26 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 -3. 0 2 .28 0 .00 0.00 0 .00 0.00 0 .00 0 .00 -2. 5 2 .35 0.00 0.00 0.00 0.00 0.00 0 .00 -3.0 2.38 0 .00 0 .00 0 .00 0.00 0 .00 0.00 -2. 0 2 .41 0 .00 0.20 0 .17 0.00 0 .00 0 .00 -2. 5 2 .41 0.00 0 .00 0.47 0.00 0 .00 0 .00 -2. 5 2 .43 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 -3. 0 2 .47 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 0 2.48 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 -3. 0 2.53 0 .00 0 .00 0 .00 0 .00 0.00 0.00 -2. 5 2.55 0 .00 0 .00 0 .00 0.00 0 .00 0.00 -2. 0 2 .56 0 .00 0 .20 0.00 0.00 0 .00 0.21 -3. 0 2.59 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 0 2 6 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 5 2.64 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -2.0 2 .65 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 -2.5 2 .69 0 .00 0 .00 0 .00 0.00 0 .00 0.00 -1. 5 2 .79 0 .00 0 .00 0 .00 0 .07 0 .00 0.37 -1. 5 2 .81 0 .00 0 .00 0 .00 0.00 0 .00 0.00 -2. 0 2 .86 0.00 0 .00 0 .00 0.00 0 .00 0 .00 1. 5 2 .87 0.00 0 .15 0 11 0.00 0 .11 0.55 -1. 5 2 .89 0 .00 0 .00 0 .00 0.00 0 .00 0.00 -3. 0 2.94 0 .00 0 .00 0.00 0.00 0 .00 0.00 -1. 5 2 .99 0 .00 0 .00 0 .05 0.00 0 .00 0 .00 -2.0 2 .99 0 .00 0 .00 0 .00 0.00 0 .36 0 21 -1. 5 3 .07 0.00 0 .00 0 .00 0.00 0.00 0.00 Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, low-energy tidal study.

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APPENDIX 3. (continued) 112 Neap tide, low-energy tidal-cycle study (September 3, 1991) L h I ower swas samples PHI CHI 700 800 900 1000 1100 1200 1300 I Lithic fragments 3 0 1.58 0 00 0 .00 0 .00 0 .00 0 .00 0 00 0 .94 Phosphate -3. 0 1 .61 0.00 0 .00 0 .00 0 .00 0.00 0.00 0 .00 Phosphate -3. 5 1 .66 0 00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 Lithic fragments -2. 5 1.66 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Lithic fragments -2.5 1 .73 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -2.0 1 .76 0 28 0 .65 0 .00 0 00 0.00 0 .00 0 .00 Phosphate -3.5 1.82 2.57 0 .00 0.00 0.00 0 .00 0.00 0.00 Lithic fragments -2.0 1.83 0 00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 Equant whole bivalves -3. 5 1.86 3.89 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Elongate shell fragments -3. 5 1 86 0.00 0 .00 0 .00 0 .00 0 .00 0 00 0.00 Elongate shell fragments -3. 5 1 .92 2 95 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 Equant shell fragments -1. 5 1 .98 0 36 0 .11 0 .00 0 .00 0.00 0 00 0 .00 Equant shell fragments -3.5 1 .98 0.00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 Elongate shell fragments -1.5 2.11 0.89 0 42 0 .48 0 04 0 .00 0.00 0 .00 Minera lized she ll s -3.0 2.26 4.19 0 .00 0 .80 0.00 0 .00 0.00 0.00 Decomposed shells -3.0 2.28 1.34 0 65 0.00 0 .00 0 .00 0.00 0.00 Mineralized shells -3.5 2 .29 0 00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 Whole Arks -2. 5 2.35 0 53 0 26 0 63 0 .00 0 .00 0 .00 0.00 Decomposed shells -3. 0 2 38 5 36 0 65 0 .00 0.30 0 .00 0 00 0 .00 Equant shell fragments -2. 0 2.41 1.42 0 43 0.34 0 .10 0 .35 0 .28 0.00 Equant whole bivalves ( sm) -2.5 2.41 1.51 0.00 0.63 0 .00 0.00 0.00 0 .00 Mineralized shells -2.5 2.43 0.53 0 00 0 .00 0 .00 0.00 0 .00 0.00 Whole Arks -3.0 2.47 1.34 0.00 0.00 0 .30 0 .00 0.00 0 .00 Decomposed shells -3. 0 2 .48 2.01 0.00 0 .00 0 .00 0.00 0.00 0.00 Equant whol e bivalves -3. 0 2 53 2.51 1.31 0.00 0 .00 0.00 0 .00 0.00 Elongate fragments -2. 5 2 55 0 53 0 00 0 .21 0 .00 0.00 0 .00 0 .00 Mineralized shells -2. 0 2 .56 6 82 1 90 0 89 0 22 0 .12 0 .55 0 .00 Whole Arks -3.0 2 .59 0 00 0 00 0 80 0.00 0 .00 0 .00 0 .00 Equant shell fragments -2. 0 2 .60 1.42 0 .81 0 20 0 .21 0 .00 0 .00 0 .00 Decomposed shells -2.5 2.64 0.00 0 26 0 00 0 00 0 .00 0 .00 0.00 Coquinas -2. 0 2 .65 1.42 0 27 0.00 0 .10 0 .00 0 .00 0 .00 Equant whole bivalves -2. 5 2 69 1 33 0 26 0 63 0 .00 0 .00 0 00 0 .00 Equant whole bivalves -1. 5 2.79 1 78 2 .11 0 .71 0 .21 0 .30 0 .04 0 .00 Whole Arks -1. 5 2 .81 4 45 1 58 0 89 0 .21 0 .19 0 04 0 .00 Whole Arks -2. 0 2.86 0 .71 1 08 0 00 0 .10 0 .00 0 .00 0 .00 Circular shell fragments -1. 5 2 .87 5.87 2 .11 2.62 0 .76 0.26 0 .14 0 .20 Decomposed shells -1. 5 2.89 0.89 0 53 0 30 0 00 0.00 0 .00 0 .00 Coquinas -3. 0 2.94 0 00 0 00 0 00 0.60 1 12 0 .00 0 .00 Circular whole bivalves -1. 5 2 99 2 67 2 63 0.00 0 .17 0 .00 0 04 0.00 Circular whole bivalves -2.0 2.99 2 .13 0 27 0 25 0 .10 0 .00 0.00 0.07 Whole Arks -1. 5 3 07 0 89 1 05 0 06 0 00 0 .00 0.00 0.00 Table 17. Chi weight-percent distributions for the gravel fraction of the lower swash samples from the neap tide, low-energy tidal study.

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APPENDIX 3. (continued) 113 Neap tide, lowenergy t idal-c ycle study L h I ower swas samples Lithic fragments Phosphate Phosphate Lithic fragments Lithic fragments Phosphate Phosphate Lithic fragments Equant whole b i valves Elongate shell fragments Elonga t e shell fragments Equant shell fragments Equant shell fragments Elongate shell fragments Mineralized shells Decomposed shells Mi neralized shells Who l e Arks Decomposed shells Equant shell fragments Equant whole b i va l ves (sm) Mineralized shells Whole Arks Decomposed she ll s Equant whole b i valves Elongate fragments Mi neralized shells Whole Arks Equant shell fragments Decomposed shells Coquinas Equant whole bivalves Equant whole bivalves Whole Arks Whole Arks Circular shell fragments Decomposed shells Coquinas Circular whole bivalves Circular whole b iv alves Whole Arks Table 17. (cont'd) PHI CHI 1400 1500 1600 1700 1800 1900 2000 -3.0 1 .58 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -3.0 1 61 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 -3.5 1 .66 0 .00 0 .00 3.10 0 .00 0 .00 0 .00 0.00 2 5 1 .66 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 5 1.73 0 .00 0 .00 0.00 0.00 0 .00 0 .00 0 .00 -2. 0 1 .76 0 .00 0 .00 0.00 0 .00 0 .00 0 .20 0 .30 -3. 5 1 .82 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 2 0 1 .83 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 5 1 .86 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 -3. 5 1 .86 0 .00 2 .96 0 .00 0.00 0 .00 0 .00 0 .00 -3. 5 1 .92 0 .00 0.00 0 .00 0.00 0 .00 0.00 0 .00 -1.5 1 .98 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 -3. 5 1.98 0 .00 4 .48 0 .00 0 .00 0 .00 0 .00 0 .00 -1.5 2.11 0 .00 0 .00 0 .00 0 .00 0.00 0 .57 0 .37 -3. 0 2.26 3 .51 1 .58 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 0 2.28 0 .00 0.73 0 .68 0 .00 0 .00 0 .00 0.00 -3. 5 2 .29 0 .00 2 .68 0.00 0 .00 0 .00 0 .00 0 .00 -2. 5 2 .35 0 .00 0 .00 0 .58 0 .00 0.00 0.00 0.00 -3. 0 2 .38 1.17 0.00 0 .00 0 .00 0.00 0.58 0.00 -2. 0 2.41 0.00 0.47 0.00 0 .00 0 .00 0 .75 0 .56 -2. 5 2.41 0.00 0.00 0.00 0.00 0 .00 0 .00 0 .18 -2. 5 2.43 0.00 0.00 0 .00 0.32 0 .00 0 .00 0.00 -3. 0 2.47 0.00 1.52 0 .00 0 .00 0 .00 0 .00 0.00 -3.0 2.48 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 -3. 0 2 .53 0.00 1.52 1 .02 0.00 0.00 0 .00 0 .00 -2. 5 2 .55 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 -2. 0 2 .56 0.00 0 .23 0.75 0 .00 0 .00 2 51 1.50 -3. 0 2 5 9 0.00 0 .73 0.00 0 .00 0 .00 0 .00 0.41 -2. 0 2 .60 0 .28 0 .47 0 1 6 0 .00 0 .00 0 .75 0.64 -2.5 2.64 0.00 0 .24 0 .00 0.00 0.00 0 .00 0 .00 -2.0 2 .65 0 .00 0 .00 0 .00 0.00 0.00 0.40 0 .30 -2. 5 2 .69 0 .00 0.24 0 .00 0 .00 0.00 0 .00 0.18 -1.5 2.79 0 .06 0.1 2 0.45 0.25 0 .21 1 .37 1.49 -1.5 2.81 0 .06 0 .06 0.22 0 .12 0.10 1.71 2.48 -2. 0 2 .86 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0 .00 -1. 5 2 .87 0 .06 0 .10 0 .07 0.57 0 .00 4 .68 6 .44 -1. 5 2 .89 0 .00 0 .00 0 .00 0 .00 0 .00 1.71 0 .62 -3. 0 2 .94 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 -1. 5 2 .99 0 .00 0 .12 0 .00 0 .05 0.00 1.37 0.99 -2. 0 2.99 0 .00 0 .00 0.16 0 .00 0.00 0 .40 0 .45. 1 5 3 .07 0 .06 0 .00 0 .00 0.00 0.00 0 .00 0.00 Chi weight-percent distributions for the gravel fraction of the lower swash samples from the neap tide, low-energy tidal study.

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APPENDIX 3. (continued) 114 Neap tide, low-energy tidal-cycle study (September 3, 1991} Upper swas h samples PHI CHI 700 800 900 1000 1100 1200 1300 Lithic fragments 3.0 1 58 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Phosphate -3.0 1 .61 0 .00 0 .00 0.00 0 .00 0 .00 0 00 0 .00 Phosphate -2. 5 1 66 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 Lithic fragments -2.5 1 73 0.00 0 .00 0.00 0.00 0.00 0 .00 0 .00 Lithic fragments -2.0 1 76 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0.00 Phosphate -2. 0 1 63 0 .00 0 .00 0.00 0.00 0 .00 0 00 0 .00 Phosphate -3.5 1 90 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 Lithic fragments -1.5 1.98 0 .16 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Equant whole bivalves -1. 5 2 .11 0 .24 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 Elongate shell fragments -3.0 2 26 0 .40 0 .00 0.00 0 .00 0 .00 0 .00 0.00 Elongate shell fragments -3.0 2.28 0 .00 0 .00 0.00 0 .00 0.00 0 .00 0.00 Equant shell fragments -2. 5 2 35 0.00 0 .00 0.00 0 .00 0 .00 0.00 0.00 Equant shell fragments -3. 0 2 38 0 .40 0 .43 0.00 0.00 0 .00 0 .00 0 .00 Elongate shell fragments -2.5 2 .41 0 .33 0 .06 0.00 0 .00 0.00 0 00 0 .00 Mineralized shells -2.0 2 .41 0 44 0 .44 0.00 0.00 0 .20 0.00 0.00 Decomposed shells -2. 5 2 43 0.00 0 .00 0.00 0 .00 0.00 0.00 0 .00 Mineralized shells -3. 0 2 47 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Whole Arks -3. 0 2 48 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 Decomposed shells -3. 0 2.53 0 .81 0 .00 0.00 0.00 0 .00 0.00 0 .00 Equant shell fragments -2.5 2 55 0 .16 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Equant whole bivalves (sm) -2.0 2 .56 0 88 0 50 0.00 0 .00 0.00 0 .10 0 .00 Mineralized shells -3. 0 2.59 0 40 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 Whole Arks -2. 0 2 .60 0 44 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 Decomposed shells -2. 5 2 .64 0 00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 Equant whole bivalves -2.0 2 65 0 00 0.15 0.00 0 .00 0.00 0.00 0 .00 Elongate fragments -2. 5 2 .69 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 Mineralized shells -1. 5 2 .79 1.19 0 50 0 .11 0.14 0.00 0 .05 0 .08 Whole Arks 1 5 2 .81 0 95 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 Equant shell fragments -2. 0 2 .86 0 00 0 .00 0 .00 0.00 0 .00 0 .11 0.00 Decomposed shells -1.5 2 87 2 .63 1.24 0 .23 0 .34 0 .08 0 .15 0 .00 Coquinas -1. 5 2 .89 0 80 0.25 0.11 0 .07 0 .00 0 .00 0 .00 Equant whole bivalves -3.0 2 94 0.00 0 .00 0.00 0 .00 0.00 0.00 0.00 Equant whole bivalves -1.5 2 .99 1.19 0 .37 0 .00 0.00 0 .00 0 .05 0.00 Whole Arks -2. 0 2 .99 0.44 0 .16 0.00 0.00 0 .00 0 .10 0 .00 Whole Arks -1.5 3 .07 0 .80 0 .07 0.06 0 .00 0.00 0 .00 0 .00 Table 18. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the neap tide, low-energy tidal study.

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APPENDIX 3. (continued} 115 Neap tide, low-energy tidal-cycle study Upper swash samples Lith i c fragments Phosphate Phosphate Lithic fragments Lithic fragments Phosphate Phosphate Lithic fragments Equant whole bivalves Elongate shell fragments Elongate shell fragments Equant shell fragments Equant shell fragments Elongate shell fragments Mineralized shells Decomposed shells Mineralized shells Whole Arks Decomposed shells Equant shell fragments Equant whole bivalves (sm) Mineralized shells Whole Arks Decomposed shells Equant whole bivalves Elongate fragments Mineralized shells Whole Arks Equant shell fragments Decomposed shells Coquinas Equant whole bivalves Equant whole b i valves Whole Arks Whole Arks Table 18. (cont'd} PHI CHI 1400 1500 1600 1700 1800 1900 2000 -3.0 1.58 0.00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 -3. 0 1 .61 0 .00 0.00 0.00 0 .00 0 .00 0 .00 0 .00 -2. 5 1 .66 0 .00 0.00 0.00 0 .00 0.00 0.00 0.00 -2.5 1.73 0 .00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 -2.0 1.76 0 .00 0.00 0 .00 0.00 0 .00 0.00 0.00 -2.0 1 .83 0 .00 0.00 0 .00 0.00 0 .00 0.00 0.00 -3. 5 1 .90 0.00 0.00 0.00 0.00 0.00 3.16 0.00 -1.5 1 .98 0 .00 0.00 0 .00 0 .00 0.00 0 .00 0.00 -1. 5 2.11 0 .00 0.00 0 .00 0 .00 0 .00 1.18 0.32 -3. 0 2 .26 0 .00 0 .00 0 .00 0 .00 2.29 5 01 0.00 -3.0 2.26 0 .00 0 .00 0 .00 0.00 0 .00 2 .01 0.00 -2.5 2.35 0 .00 0 .00 0 .00 0 .00 0 .30 0 .69 0.00 -3.0 2 .36 0 .00 0 .00 0 .00 0.70 1.13 13.03 0 .00 -2.5 2.41 0 .00 0 .00 0 .00 0.00 0 .00 3.39 0 .00 -2.0 2 .41 0.00 0 .00 0.00 0 .00 0 .00 5 .35 0.15 -2. 5 2.43 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 -3. 0 2.47 0.00 0 .00 0 .00 0 .00 0.00 0.00 0.00 -3.0 2.48 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0.00 -3. 0 2.53 0 .00 0 .00 0.00 0 .00 0.00 1.25 0.00 -2. 5 2.55 0 .00 0 .00 0 .00 0.00 0.00 0.00 0 .00 -2. 0 2.56 0.00 0.00 0.00 0 .00 0.23 10.16 0 .15 -3. 0 2 .59 0.00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 -2. 0 2.60 0.00 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 5 2.64 0 .00 0.00 0 .00 0 .00 0 .00 0.69 0 .00 -2. 0 2.65 0.00 0.00 0 .00 0 .00 0.23 2 .67 0 .00 -2. 5 2.69 0.00 0 .00 0.00 0 .00 0 .00 0.69 0.00 -1.5 2 .79 0 .08 0.08 0.08 0 .09 0.09 3.54 0 .97 -1.5 2 .61 0 .00 0 .00 0 .00 0.00 0.00 0.00 0 .00 -2. 0 2.66 0 .00 0 .00 0 .00 0.00 0.00 0.53 0 .00 -1.5 2.67 0 .00 0 .00 0 .00 0.09 0.52 7.07 2.90 -1. 5 2.69 0 .00 0 .00 0.00 0.00 0 .09 2.36 0.32 -3. 0 2.94 0 .00 0 .00 0.00 0.00 0.00 0 .00 0 .00 -1. 5 2 .99 0.00 0 .00 0.00 0.00 0 .09 3.54 0 .32 -2. 0 2.99 0.00 0 .00 0.00 0 .00 0.24 4 01 0.00 -1. 5 3.07 0.00 0 .00 0.00 0 .00 0.00 1 .18 0.00 Chi weight-percent distributions for the gravel fraction of the upper swash samples from the neap tide, low-energy tidal study.

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APPENDIX 3. (continued) 116 Spring t ide, highenergy tidal-cycle study (September 3, 1991) Lowerswas h I samples PHI CHI 730 630 930 1030 1130 1230 Lithic fragments -3. 0 1 .56 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 Phosphate -3. 0 1 6 1 0 .00 0 .00 0 .00 0 .00 0.00 0.00 Phosphate -2.5 1.66 0 .00 0.00 0.00 0.00 0 .00 0 .00 Lithic f ragments -2. 5 1.73 0 .00 0 00 0 .00 0.00 0 .00 0 .00 Lithic fragments -2. 0 1.76 0 .00 0.00 0 .00 0 .00 0.17 0 .00 Phosphate -2. 0 1 .63 0 .00 0.00 0 .00 0.00 0.17 0.00 Phosphate -1. 5 1 .96 0 .00 0.00 0 .00 0 .11 0 .72 0 .36 Lithic fragments -1. 5 2 .11 0 22 0 .06 0 .00 0 .11 0 .29 0 36 Equant whol e bivalves -3.0 2 .26 0 .84 0 .00 0 .00 0 .00 0 .00 0 .00 Elongate shell fragments -3. 0 2 .26 0 .84 0 .00 0 .46 0 .00 0 .67 0 .00 Elongate shell fragments -2. 5 2.35 0 .00 0 .00 0 .00 0 .00 0 .52 0 .34 Equant shell fragments -3. 0 2 .36 0 42 0 .00 0 .46 0 .00 1 .29 0 .36 Equant shell fragments -2. 5 2.41 0 .23 0.00 1 .01 0 .00 0 69 0 .33 Elongate shell fragments -2. 0 2 .41 0 .99 0 .26 0 .71 0 .00 0 .66 0 16 Mineralized shells -2. 5 2 .43 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 Decomposed shells -3. 0 2 .47 0 .00 0.00 0 .00 0 .00 0 .00 0 .36 Mineralized shells -3. 0 2 .46 0 .00 0.00 0.00 0.00 0 .00 0.00 Whol e Arks -3.0 2 53 0.00 0 .00 0 .00 0 .00 0.00 0 00 Decomposed shells -2. 5 2 55 0.00 0.00 0 .00 0 .00 0 .00 0 00 Equant shell fragments -2. 0 2 56 2 35 0 14 0.91 1 .11 3 .53 0 .76 Equant whole bivalves (sm) -3. 0 2 59 0.00 0.00 0 .00 0.00 0 .00 0 .00 Mineralized shells -2. 0 2 60 0 00 0.00 0 .00 0 .00 0.17 0 .00 Whole Arks -2.5 2 64 0 .00 0.00 0 .00 0 .00 0.00 0 .33 Decomposed shells -2. 0 2 65 0 32 0.00 0 .34 0.00 0.00 0 .16 Equant whole bivalves -2. 5 2 69 0 .00 0 .00 0 .00 0 .00 0.26 0 .00 Elongate fragments -1. 5 2 79 0.87 0 .35 0 .37 0 1 5 1 .01 0 .23 Mineralized shells -1. 5 2 .61 0 .00 0 .00 0 .00 0.11 0.72 0.36 Whole Arks -2. 0 2 66 0.00 0 .00 0 .00 0 .00 0 .00 0 .00 Equant shell fragments -1. 5 2 67 4 34 0 32 5.40 2 19 9 49 4 .11 Decomposed shells -1. 5 2.69 0.14 0 .08 0 .37 0 22 0 72 0.06 Coquinas -3. 0 2.94 0 .00 0.00 0.00 0.00 0 .00 0.00 Equant whole bivalves -1. 5 2 99 0 22 0 .00 0 .37 0 15 0 72 0.36 Equant whole bivalves -2. 0 2 99 0 .00 0 .00 0 .71 0 .00 0 .28 0.00 Whole Arks 1 5 3 07 0 .00 0 .00 0 .07 0 .00 0 .00 0 .15 Table 19 Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, high-energy tidal study.

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APPENDIX 3. (continued) 117 Spring t ide, high-energy tidal-cycle study L h I ower swas samples Lithic fragments Phosphate Phosphate Lithic fragments Lithic fragments Phosphate Phosphate Lit hic fragments Equant whole bivalves Elongate shell fragments Elongate shell fragments Equant shell fragments Equant shell f ragmen t s Elongate shell fragme nt s Mineralized she ll s Decomposed shells Mineralized shells Whole Arks Decomposed shells Equant shell fragments Equant whole b i valves (sm) Mineralized shells Whole Arks Decomposed she lls Equant who l e bivalves Elongate fragments Mineralized shells Whole Arks Equant shell fragments Decomposed shells Coquinas Equant whole bivalves Equant whole bivalves Whole Arks Table 19. (cont'd) PHI CHI 1330 1430 1530 1630 1730 1830 1930 -3. 0 1 .58 0 .59 0 .00 0.00 0.00 0 .00 0.00 0 .00 -3. 0 1.61 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 -2. 5 1 .66 0.00 0 .00 0.00 0 .00 0 .00 0.00 0 .00 -2. 5 1 .73 0 .00 0 .28 0.00 0 .00 0 .00 0 .00 0 .00 -2. 0 1.76 0 .00 0.18 0 .00 0 .00 0.00 0 .00 0 .00 -2. 0 1 .83 0.00 0 .36 0 .00 0 .00 0.00 0 .00 0.00 -1. 5 1 .98 0.00 0 .62 0.00 0 .00 0.00 0.00 0 .00 -1. 5 2 .11 0.35 0.00 0 .00 0 .09 0 .00 0 .00 0 .00 -3. 0 2 .26 0.00 0 .51 0 .94 0 .00 0 .00 0 .00 0 .00 -3. 0 2 28 0.00 1 .02 0 .94 0 .00 0.00 0 .00 0 .00 -2.5 2 .35 0 .00 0 .00 0 .19 0 .27 0 .00 0 .00 0 .00 -3.0 2 .38 0 .59 0 .85 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 5 2 .41 0 .00 0 .74 0 .18 0.27 0 .00 0.00 0 .00 -2. 0 2 .41 0 .89 0 .73 0 .00 0 .52 0 .27 0 .00 0 .00 -2. 5 2.43 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 -3. 0 2 47 0 .00 0 .51 0 .00 0 .00 0 .00 0 .00 0 .00 3 0 2 48 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -3. 0 2 .53 0 .00 0 5 1 0.00 0.00 0 .00 0 .00 0 .00 -2.5 2 .55 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 0.00 -2. 0 2 .56 0 .72 3.09 0 .80 1 .02 0 .27 0.12 0.00 -3. 0 2.59 0.00 0.00 0.00 0.00 0 .00 0.00 0.00 -2. 0 2 .60 0.00 0.36 0 .00 0 .00 0 .00 0.00 0 .00 -2. 5 2 .64 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 0 2 .65 0 .07 0 .91 0 .14 0 .00 0 .00 0 .00 0 .00 -2. 5 2 .69 0 .00 0.28 0 .18 0 .00 0 .00 0 .00 0.00 -1. 5 2 .79 0 .70 0.87 0 .43 0 .91 0 .19 0 .00 0 .00 -1.5 2 .81 0 .00 0.62 0 .00 0 .00 0 .00 0 .00 0 .00 -2. 0 2.86 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 0.00 -1.5 2.87 3 .62 8 .08 2.47 1 .51 1 .14 0 .34 0 .14 -1. 5 2.89 0.21 0 .37 0 .09 0 .00 0 .09 0 .00 0 .00 -3. 0 2 .94 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -1. 5 2.99 0.35 0 .62 0 .64 0 .69 0 .09 0 .00 0.00 2 0 2.99 0.72 0 .18 0.00 0 .41 0 .00 0 .00 0.00 1 5 3 .07 0 .00 0 .00 0.00 0 .23 0 .00 0.00 0 .00 Chi weight-percent distributions for the gravel fraction of the lower swash samples from the spring tide, highenergy tidal study.

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APPENDIX 3. (continued) 118 Spring tide, high-energy tidal-cycle study (September 3 1991) Upper swash sam pies PHI CHI 730 830 930 1030 1130 1230 Lithic fragments -3. 0 1.58 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -3. 0 1 .61 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -2.5 1 66 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 Lithic fragments -2. 5 1 73 0 00 0 .00 0 .00 0 00 0 .00 0 .00 Lithic fragments -2.0 1.76 0 00 0 .00 0 .00 0 00 0 .00 0.00 Phosphate -2. 0 1 83 0 00 0 .00 0 .00 0 .00 0 .00 0 .00 Phosphate -1. 5 1 98 0 .14 0 .00 0 .00 1 64 0 .00 0 .00 Lithic fragments -1. 5 2 .11 0 00 0 .00 0 .00 0 55 0 .16 0 .12 Equant whole b i valves -3.0 2 26 0 00 0 .00 0 .00 0.00 0 00 0.00 Elongate shell fragments -3. 0 2 28 0 00 0 .00 0 .00 0.45 0 .00 0 .00 Elongate shell fragments -2. 5 2.35 0 .00 0 .00 0.00 0.00 0 .00 0 .00 Equant shell fragments -3. 0 2 38 0.00 0 .00 0.00 0.88 0 .35 0 .63 Equant shell fragments -2.5 2.41 0 00 0 .00 0 .00 0 64 0 .00 0 .20 Elongate shell fragments -2. 0 2 .41 0 00 0 .00 0 .00 0 79 0 .00 0 .00 Minera lized shells -2. 5 2.43 0 .00 0 00 0 .00 0 00 0 .00 0 .00 Decomposed shells -3. 0 2.47 0 00 0 00 0.00 0.00 0 .00 0 .00 Mineralized shells -3.0 2 48 0 00 0 .00 0 .00 0 00 0 .00 0.00 Whole Arks -3. 0 2 53 0 00 0 .00 0 .00 0 00 0 .00 0 .00 Decomposed shells -2. 5 2 55 0 .00 0 .00 0 .00 0 24 0 .00 0 .00 Equant shell fragments -2. 0 2 56 1 24 0 .29 0 .13 2 .12 0 94 0 .67 Equant whole bivalves (sm) -3. 0 2 59 0 .00 0 .00 0 .00 0 .00 0 .00 0.00 Mineralized shells -2. 0 2.60 0 .00 0.00 0 .00 0 .00 0 00 0 .00 Whole Arks -2. 5 2 64 0 .00 0 37 0 .00 0.00 0 00 0 .00 Dec om posed shells -2. 0 2 65 0.00 0 .00 0 .00 0 .26 0 .00 0 .00 Equant whole bivalves -2. 5 2 69 0 .00 0 .00 0 .00 0.24 0 .00 0 00 Elongate fragments -1. 5 2 79 0 .27 0.16 0 .00 1 .64 0 32 0 .29 M i neralized shells -1. 5 2 .81 0 .14 0.00 0 .00 1.64 0 .00 0 .00 Whole Arks -2. 0 2 86 0 .00 0 .00 0 .00 0.26 0.00 0 .00 Equant shell fragments -1. 5 2 87 1 .49 0 .19 0.22 3.83 1 .89 2 45 Decomposed shells -1. 5 2 89 0 .14 0 .00 0 .00 0 .77 0.09 0 .17 Coquinas -3. 0 2 94 0 .00 0 .00 0 .00 0.00 0.00 0 .00 Equant whole bivalves -1. 5 2 99 0. 27 0 .00 0 .00 0.33 0.32 0 .21 Equant whole bivalves -2. 0 2.99 0.41 0 .00 0 .00 0 .79 0.00 0 .10 Whole Arks -1. 5 3 07 0 .00 0 .00 0 .00 0 .00 0 .00 0 .08 Table 20. Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, high-energy tidal study.

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APPENDIX 3. (continued) 119 Spring tide, high-energy tidal-cycle study Upper swash samples Lithic fragments Phosphate Phosphate Lithic fragments Lithic fragments Phosphate Phosphate Lithic fragments Equant whole bivalves Elongate shell fragments Elongate shell fragments Equant shell fragments Equant shell fragments Elongate shell fragments Mineralized shells Decomposed shells Mineralized shells Whole Arks Decomposed shells Equant shell fragments Equant whole bivalves (sm) Mineralized shells Whole Arks Decomposed shells Equant whole bivalves Elongate fragments Mineralized shells Whole Arks Equant shell fragments Decomposed shells Coquinas Equant whole bivalves Equant whole bivalves Whole Arks Table 20. (cont'd) PHI CHI 1330 1430 1530 1630 1730 1830 1930 -3.0 1 .58 0 .00 0 .00 0 .00 0.00 0.00 0 .00 0 .00 -3. 0 1.61 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 -2. 5 1.66 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 0.00 -2. 5 1.73 0.00 0 .00 0.00 0.00 0.00 0 .00 0.00 -2.0 1 .76 0.00 0.00 0 .18 0 .00 0 .00 0.00 0 .00 -2.0 1 .83 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -1.5 1 .98 0 .08 0 .00 0.00 0 .00 0 .07 0 .00 0.00 -1. 5 2 .11 0.00 0.00 0 .00 0.00 0.00 0 .00 0 .00 -3. 0 2 .26 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 -3.0 2 .28 0 .00 0.00 0.00 0 .00 0.00 0 .00 0 .00 -2. 5 2 .35 0.00 0 .00 0 .00 0.00 0 .00 0 .00 0 .00 -3. 0 2 .38 0 .00 0.00 0 .00 0.00 0.00 0.00 0 .00 -2. 5 2 .41 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 -2. 0 2 .41 0 .16 0.00 0 .00 0 .00 0 .47 0 .00 0 .00 -2. 5 2 .43 0 .00 0 .00 0 .00 0.00 0.00 0.00 0 .00 -3. 0 2.47 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 -3. 0 2 .48 0 .00 0 .00 0.00 0.00 0 .00 0.00 0 .00 -3. 0 2 .53 0.00 0 .00 0.00 0 .00 0 .00 0 .00 0 .00 -2.5 2 .55 0 .00 0.00 0.00 0.00 0 .00 0.00 0 .00 -2. 0 2 .56 0 .16 0 .16 0.18 0 .00 0.00 0.00 0.00 -3.0 2.59 0 .00 0.00 0 .00 0.00 0.00 0 .00 0 .00 -2. 0 2 .60 0 .00 0.00 0 .00 0.00 0 .00 0 .00 0 .00 -2.5 2.64 0 .00 0.00 0.00 0.00 0.00 0 .00 0.00 -2.0 2 .65 0 .00 0.00 0.00 0.00 0.00 0.00 0 .00 -2.5 2.69 0.00 0.00 0 .00 0.00 0 .00 0 .00 0.00 -1. 5 2.79 0.20 0.00 0 .00 0 .13 0 .09 0.07 0.05 -1.5 2.81 0 .08 0.00 0 .00 0.00 0 .07 0.00 0.00 -2.0 2.86 0.00 0.00 0 .00 0 .00 0 .00 0.00 0 .00 -1. 5 2.87 1.88 0 .28 0 .37 0 .52 0 .77 0.22 0.05 -1.5 2.89 0 .08 0 .04 0 .04 0 .00 0.18 0 .00 0 .00 -3. 0 2 .94 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -1.5 2 .99 0 .00 0 .00 0 .00 0 .07 0 .00 0 .00 0.00 -2. 0 2.99 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 0 .00 -1.5 3.07 0 .00 0 .00 0 .00 0 .00 0.00 0 .00 0 .00 Chi weight-percent distributions for the gravel fraction of the upper swash samples from the spring tide, highenergy tidal study.

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APPENDI X 4 WAVE AND TIDE DATA FROM THE USGS WAVE GAUGE WAVE AND TIDE PARAMETERS Spring tide, low-energy tidal-cycle study (J.me 26, 1991) Time Wave Height Peak Period Central Angle Wave Wavelength Tide L.evef (24 (meters} (seconds} (radians} Steepness (meters} (an} 700 0 .12 5 .56 4 .10 0.003 33.36 12.78 800 0 .11 5 .31 4 .10 0.003 40.09 25.93 900 0.13 5 .71 4 .17 0.004 34.62 38.65 1000 0.13 5 .41 3.98 0.004 32.41 46.27 1100 0.15 5.62 4 .09 0.004 33.85 46.08 1200 0 .13 5.34 4 .15 0.004 31.96 44.69 1300 0 .13 5 .80 4 .19 0.004 35.15 27.44 1400 0 .13 5 .49 4.18 0.004 33.12 9.44 1500 0 .13 6 .39 4 .17 0 .003 39.40 -9.66 1600 0 .13 6 .23 3 .92 0.003 37.77 -29.22 1700 0.13 5 .69 4.22 0 .004 34.36 -44.17 1800 0.19 5 .73 4 .13 0.005 34.89 -50.20 Neap tide, low-energy tidal-cycle study (September 3 1991) Time Peak Period Central Angle Wave Wave length Tide Level (24 (meters} (seconds} (radians} Steepness (meters} (an} 730 0 .26 5.31 4.41 0 .008 31.74 25.56 830 0 .26 5.25 4.41 0.008 31.30 32.71 930 0 .25 3 .93 5.72 0.012 21.16 21.78 103) 0 .26 4 .94 4 .87 0.009 28.92 13.59 113:> 0 .24 3 .57 5 .74 0.013 18. 2 8 0.49 123:> 0 .19 8.77 4 .03 0.003 56.42 -17.25 133:> 0.19 7 .82 4 .07 0 .004 49.67 -33.17 143:> 0.19 8.13 4 .24 0 .004 51.93 -42.17 153:> 0.18 8 .83 4 .43 0 .003 56.42 -40.65 163J 0.18 7 .69 4.11 0.004 48.62 -37.74 173:> 0 .22 7 .65 4 .29 0.005 48.11 -28.29 183:> 0 .22 8 .99 4 .24 0.004 57.85 -15.34 193:> 0 .31 3.00 5 .96 0.023 13.60 -8.65 203) 0.29 3.01 5 .96 0.021 13.72 -0.43 Table 21. wave and t ide d ata from the USGS wave gauge a t R-75 used i n the Pearson's correlation m a t rix. 120

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APPENDIX 4 (continued) 121 WAVE AND TIDE PARAMETERS Spring tide, t i dal-cycle study (February 6 1992) Time Peak Period Central Angle Wave Wave length Tide level {24 Houtl {meters} {seconds} {radians} Steepness {meters} {an} 730 1.08 11.15 4 .70 0.015 72.54 -23.32 830 1.16 10.20 4 .57 0 .018 66.23 -18.45 930 1.28 11.99 4 .53 0 .016 78.79 -6.36 103) 1 .35 11.79 4 .59 0 .017 n .46 10.39 113) 1.41 11.70 4 .74 0 .018 76.17 22.79 123) 1.49 11.51 4 .69 0 .020 74.92 28.15 133) 1 .57 10.98 4 .76 0 .022 71.41 25.64 143) 1.47 11.51 4 .80 0.020 74.92 13.76 153) 1 .42 6.n 4 .79 0.025 56.42 0 70 163) 1 .33 10.28 4 .70 0 .020 67.21 -11 .85 173) 1 .29 11.51 4 .80 0 .017 74.92 -25.54 183) 1 .26 11.70 4 .70 0 .017 76.17 -34.07 193) 1.16 10.98 4 .74 0 .016 71.41 -37.91 Table 21. (cont'd) Wave and t ide data from the USGS wave gauge at R-75 used in the Pearson's correlation matrix.

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APPENDIX 5 GRAIN SIZE PARAMETERS 122 GRAIN SIZE AND COMPOSITIONAL DATA Spring tide, low-energy tidal-cycle study (June 26, 1991) Lower swash samples Time Mean Grain Size Standard Percent Percent (24 Hour} Deviation Gravel CaC03 700 2 60 1.49 2 .61 41.22 800 2 .11 2 06 13.19 43.88 900 -1.61 1.10 74 23 98.36 1000 2 .57 1.56 4 .01 37.38 1100 3.11 1.13 0 74 22.40 1200 -0.50 0.95 49 60 97.89 1300 1.05 1 96 15 82 73 36 1400 3 .24 1 10 1 95 17.08 1500 2 .59 1 70 2 70 31.24 1600 3.52 0 .61 0.07 7.65 1700 3.51 0 60 0.12 7 .18 1800 3.53 0.50 0.14 4.99 Uppe r swash samples Time Mean Grain Size Standard Percent Percent (24 Hour} Deviation Gravel CaC03 700 2.53 1. 71 4 67 39.27 800 2 09 2 .18 15.77 40 23 900 -1.10 1.44 59 17 96 75 1000 -0.21 2 27 45 06 81. 83 1100 -0.31 1.98 46.80 86.84 1200 0.36 1 53 21.64 74.61 1300 2.37 1 .5 8 4.56 45.66 1400 3 .16 1.00 0 74 17.85 1500 2 .73 1 29 1.73 38. 02 1600 3 .47 0 88 0 .81 8.04 1700 3.47 0 73 0 .46 7.40 1800 3.49 0.73 0 59 6.44 Table 22. Grain size and compositional data for the surface-sediment samples from the spring tide, low-energy study. Data used as input for the Pearson's correlation matrix.

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APPENDIX 5. (continued) 123 GRAIN SIZE AND COMPOSITIONAL DATA Neap tide, low-energy t idal-cycle study (September 3 1 991) Lower swash samples Time Mean Gra i n Size Standard Percent Percent (24 Hour) Deviation Gravel CaC03 730 -1.79 1 52 79 26 98 27 830 -0. 40 1.48 34 08 94.40 930 -0. 06 1.33 22 13 94.81 1030 1 02 1.52 7 39 83 14 1130 2.59 1 .26 1 45 40 37 1230 2 37 1 .41 1 96 47 24 1330 3 .31 0 90 0 94 12.69 1430 2.99 1.54 5 20 18 06 1530 2 90 1 84 7.69 17.42 1630 2 72 1.74 6 52 25 95 1730 2 .21 1.56 2.65 48.54 1830 2.31 1.61 4 48 43.67 1930 0 54 1.68 17. 45 86 26 2030 -0.65 1 02 36. 72 97 43 Upper swash samples Time Mean Grain Size Standard Percent Percent {24 Hour} (phi} Deviation Gravel CaC03 730 -0. 44 1 53 32.17 95.82 830 0 .61 1.51 10 .91 88 .60 930 1 94 1.57 3 86 61.52 1030 2 44 1.50 2 56 41.93 1130 2 55 1.29 1.19 42.74 1230 2 73 1 26 1 92 36 74 1330 3 24 0 85 0 50 14.41 1430 3.24 0 .85 0 50 14 .41 1530 3 24 0 85 0 50 14 .41 1630 3 24 0 .85 0.50 14 85 1730 3 35 0 .79 0 19 10.50 1830 2.45 2 00 7 70 33 68 1930 -1.10 1 88 65. 32 91.71 2030 -0. 19 1.25 22 .51 94 77 Table 23. Grain size and compositional data for the surface-sediment samples from the neap tide, low-energy study. Data used as input for the Pearson's correlation matrix.

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APPENDIX 5. (continued) 124 GRAIN SIZE AND COMPOSITIONAL DATA Spring tide, high-energy tidal-cycle study (February 6 1992) Lower swash samples Time Mean Grain Size Standard Percent Percent (24 Hour} Deviation Gravel CaC03 730 0 30 1 56 1.35 89.14 830 1.22 1.23 57.10 76.46 930 -0.33 1.19 13.88 97.44 1030 -0.35 0.94 58.79 98.18 1130 -0. 45 1.21 2.98 95 27 1230 -0.25 1 .23 1.05 96 53 1330 -0. 17 1 35 20. 37 95.48 1430 1.30 1.03 30 99 82 .53 1530 0.05 1 16 35.00 95 54 1630 0.58 1.47 26.72 84.13 1730 1 14 1.44 17 90 74 .90 1830 1 .81 0 86 7.97 67 43 1930 1.29 1.22 1.37 76 66 Upper swash samples Time Mean Grain Size Standard Percent Percent (24 Hour} Deviation Gravel CaC03 730 1.96 1 .31 4.65 50 16 830 2 00 1.08 1 .29 71.04 930 2.00 1.11 13 00 52 09 1030 -1.09 1.04 12 35 97.98 1130 0.46 1 37 3.88 91.42 1230 0 14 1 19 5 53 93.02 1330 0.43 1 .27 0.33 90.90 1430 -1.13 1.04 3.96 97.81 1530 1 26 1.31 24 28 76.07 1630 1.95 1.23 28.11 50.69 1730 2 28 1.48 1 71 36.64 1830 2 53 1.08 14 34 33.48 1930 2.89 0 83 0.40 21.56 Table 24. Grain size and compositional data for the surface-sediment samples from the spring tide, high-energy study. Data used Pearson's correlation matrix. as input for the

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nme 1 000 Mean Grain Size 1 .000 Standard Deviation (phijl -o:e110 I -0. 420 1 000 %Grawl -o ...s 0.277 1 000 %Calcium Carbonate I -0.572If0.39 or <-0.39 are statistically significant at the 0.05 alpha level. > '0 '0 tt:1 z 0 H :>< 0\ g t-3 t-3 >rj '0 tt:1 CJl 0 z .. CJl () 0 H 0 z ::0 H () tt:1 CJl ,_. 1\J l11

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Tlme 1 000 Mean Grain Size 0 2041 1 000 Standard Deviation (phQI -0. 0441 -0.3!521 1 000 %Gra1181 -0. 1231 .. -o:aa&l o 3131 1 000 --.. %Calcium Carbonate I o .37el 0;'7201 1 000 s-Jhaq,. 0 133 1 -0. 1031 -0. 2801 -O. !!ee 1 000 IWave Height -0. 0 1 3 -0.8311 0 .335 o .eeo 1.:.::::o :en -0.5771 1 000 jwave Period 0 .1M O ell7 -0. 138 o .4871:;::,Tt:i.o : e i! 1.000 Wave Angle 0 133 0 .1o4CS o .31 e 1 o .683 1 000 !wave Steepnesa 0 220 O .C572 0 183 0 .51111. c;: --o.3a2 o .011 1 000 Ttdel.ewl -0. 0 304 o 4851 ,,,. '''o e27 -O.Mel:.: -O.ell1 0 424 0 .442 1 000 %Swuh .,.0 717 -:-:-0 733 0.28G 0 8131 ;: ,., :. 0 737 -0.4N 0 558 I -0.4S1 0 112 0 2 1 e I \::;=:o .an 1 000 SwuhWidlh -0. 532 :: o .&311 0 400 ::=o .'eGe 1.>}' -0. 582 0 .21111 o .4111l :::::::::=: o :87o 1 t:!,t 1 000 0 .481 1 0001 0.00111 Foreahofe width 0 .{1()71 0 .41121 -o.oae 1 -0. 3331 -O.M7 .. -0.305 0.3411 O .OOQ Tlme I MGS I Std Dev I% Gra\1811 %CaC031 8-Mlah aq,. I Wave Height IWv Period IWv Angle IWv Steepnestl Tlde Levell % s-Jh I s-Jh Wldlhl Foreshore width Table 26. Output from the Pearson's correlation matrix for the neap tide, low-energy study. Geologically significant correlation coefficients are shaded, and values >0.39 or <-0.39 are statistically significant at the 0.05 alpha level. > ttl ttl tr:! z 0 H X 0'1 0 0 !j rt f-' !j (t) 0. .... IIJ 0'1

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Time 1 .000 Mean Grain Size 0 .3eol 1 000 Standard Deviation (phQI -0. 1531 -O.OQ21 1 000 %Gravel O .OGel -O.OG41 0 1181 1 .000 %CalclumCarbonate 0 1441 0 1c&l 1 000 Swash slope -o:aast o 1eo1 -0. 2021 -o.22a 1 .000 !wave Hei ght o 1..e1 -o.&401 -0. 0131 o .oeel o .I!.2SI -0.541 1 000 lwaw Period 0 1421 -0. 1581 -0.3231 0 007 1 O .ee!S 0 00$ 1 .000 !wave Angle O .!!GGI 0 0381 0 .2MI -0. 2311 0 0431 0 .3!!G -0.2!50 1 000 !wave Steepnes1 0 .2131 0 307 0 .10G 0 .2!57 0 3SS ::::o :eoel.-:=::;::,;;::,:,.:_o .74f -0.8152 0 448 1 000 Tide Level 0 3421"";., 0 : 7211 0 0451 0 045 L = O .J13 -o .2tlal====::::::::;::::=:o .&s1 0 104 0 084 0 .15615 1 .000 %Swash 0 .321 1"_;..0 .7241 0 .030 0 0171 :=:.-:., 0 .57 -0.218 0 .1!50 o .oeo o.45!51 )/) 1 000 Swash Width -0.281 I ,.;;0.7111 0 0041 0 0021 0 .1588 -0. 358 1 0 .083 o .1eo o .!Sc& I 1 .000 Foreshore width 0 .!502 0.1381 -0. 0031 -0.871 0 .1715 -0.15&4 -0.208 o .1n -0. 278 1 0001 Time I MGS I Std Oevl% Gravell %CaC031 Swah lope !Wave Height IWv Period IWv Angle IWv Steepne11l Tide Levell %Swash I Swash Wldthl width Table 27. Output from the Pearson's correlation matrix for the spring tide, high-energy study. Geologically significant correlation coeffients are shaded, and values >0.39 or <-0.39 are statistically significant at the 0.05 alpha level. 't1 't1 t%j z 0 H >< 0'1 0 0 :::1 rt 1-' :::1 c:: CD p.. ...... l'J -..1

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Time 1 000 Mean Gra i n S i ze 0 .3CXI 1 .000 Standard Deviation (phQ 0 325 0 273 1 .000 % Gravel -0.227 -0. 707 0 227 1 000 % Calcium Carbonate 0 331 0 .1154 0 .2eg o eo:z 1.000 Swuhslope -0.3&4 0 204 0.420 -O.OD1 -0. 2 1 3 1 000 Wave Height O .OS7 0 .3112 0 .188 0 .033 0 472 -0.315G 1.000 Wave Period 0 .0&4 -0. 011 -0. 222 -o.1e& 0 .14 -0.2ea 1 000 Wave Angle 0 110 0 383 0 041 0 13'1 0 .4315 0 .375 0 287 -0. 127 1.000 wave Steepness 0 101 -o. 502 -o.ow o .18:2 o .eo1 -o.402 o .44 '=:/;o it o 1 000 TKiel.eYel o eo:z o .eoo 0 .444 0 .423 0 .010 o 0 7 3 0 .01a -0. 257 0 034 0 .043 1.000 % Swash -0. 438 Q .722 o .1ee o .3112 0 .1112 0 317 o .I5Ge o .3M 0 130 1'{:)= o .;1a 1 000 SWash Width -0.1011 -0.514 -0. 081 0 133 o .eos o 380 : : : : o .231 ' o 252 :::i: 1 000 Foreshore width o 081 -o.1ea -0. 237 -o.ooe o .253 -o. 400 o o11 o .eot -o.on o .423 1 000 Time MGS Std Dev %Gravel %CaC03 Swash slope Wave Height Wave Perir: Wave Ang Wv Steepneat Tide Level % Swash Swash Width Foreshore width Table 28. Output from the Pearson's correlation matrix for three tidal studies: spring tide, low-energy; neap tide, low-energy; and spring tide, high-energy. Geologically significant correlation coefficients are shaded, and the values >0.22 or <-0.22 are statistically significant at the 0.05 alpha level. )" I'd "d t%j z 0 H >< 0\ 0 0 ::s rt 1-' ::s r:: !D s:L ():)


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