[From the U.S. Government Printing Office, www.gpo.gov]




                   Rorida
                           Tech
                   (
                     Shoreface Sediment Distribution Patterns:
                                   A Measure of Inlet Influence?





                                                          Submitted to
                                                 Sebastian Inlet Tax District





                                                          Submitted by

                                            Randall W. Parldnson, Ph.D., P.G.
                                                      Assistant Professor


                                                   Phillip F. Venanzi, M.S.
                                                     John R. White, M.S.
                                               Graduate Research Assistants











                                                          March 1993





                                Deparunent of Oceanography, Ocean Engineering, Enviromnental Science
                                     150 West University Boulevard 9 Melbourne, Florida 32901
                     S]





























                                        FLORIDA DEPARTMENT OF COMMUNITY AFFAIRS
                                             Linda Loomis Shelley, Secretary
                                         FLORIDA COASTAL MANAGEMENT PROGRAM
                                                 2740 Centerview Drive
                                             Tallahassee, Florida 323W-2100




                                          This report was financed in part by funds
                                                made available through the
                                      National Oceanic and Atmospheric Administration
                                                        Me    r











                                   EXECUTIVE SUMMARY

                  This study was designed to establish the area of inlet

             influence   based   upon    surficial   sediment    grain-size

             distribution patterns. It was hypothesized that ebb tidal

             currents at Sebastian inlet jet fine-grained littoral drift

             seaward such that the surficial sediments proximal to the

             inlet are coarser than updrift (northern) areas or distal

             downdrift (southern) areas.



                  Surficial sediment samples were collected on two

             occasions representing summer and winter climatic conditions.

             The summer samples were collected over a ten day period in

             September, 1991. The winter samples were collected over a

             fifteen day period in late April and early May, 1992.



                  To establish the area of inlet influence the graphic

             depictions of alongshore and cross-shore grain-size data

             (%gravel, %sand, %mud, and 24 phi sand-size classes) were

             visually inspected. A significant shift in the relative

             abundance of the grain-size data in the proximity of the inlet

             was interpreted to be a consequence of the inlet effect. The

             alongshore distance to this shift was then assumed to be the

             limits of inlet effect.




                  The grain-size surficial sediment distribution pattern

             within the study area suggests the area of inlet influence


                                           i









             within the shoreface is approximately -5,000 ft (updrift) to

             +6,000 ft (downdrift). Inner shelf sediment patterns suggest

             the area of influence is also approximately ï¿½5,000 ft.



                  The area of inlet influence is not masked by winter storm

             conditions although the elevated wave climate did coarsen the

             distal updrift shoreface. A fining of the distal downdrift

             inner shelf was also noted and may be genetically related to

             the shoreface coarsening.



                  This study has demonstrated that textural distribution

             patterns of surficial sediments can be used as a method to

             delineate the area of inlet influence. Within the Sebastian

             Inlet area the presence of coquina rock outcrops in downdrift

             areas proximal to the inlet has resulted in highly variable

             grain-size   distribution   patterns   which   have    hampered

             quantification of the area of inlet effect.



                  It should also be noted that the estimates of inlet

             effect presented herein are based upon the surficial sediment

             grain-size distribution patterns. Therefore, these estimates

             can only be used to delineate the limits of hydrodynamic

             influence. The data presented herein can not be used to infer

             how this hydrodynamic activity has- effected the local sediment

             budget and therefore coastal accretion or recession.rates.




                                           ii











                                       TABLE OF CONTENTS


              EXECUTIVE SUMMARY    ..........................................


              TABLE OF CONTENTS    .........................................      ii


              LIST OF FIGURES    ............................................      v


              LIST OF TABLES   ...........................................       vii


              ACKNOWLEDGEMENTS   ........................................       viii


              INTRODUCTION   ...............................................       1


              GOAL AND OBJECTIVES    ........................................      3


              BACKGROUND AND PREVIOUS WORK     ...............................     4


              STUDY AREA  .................................................        9

                    A. Location and History    ..............  o ................  9

                    B. Hydrodynamics    .....................................     10

                    C. Winds ..... o........  o........................    o ..... 11


                    D. Waves  .............................................       12


                    E. Littoral Dirft    ....................................     12


              METHODS  ...................................................        15

                    A. Design of Sampling Program      ........................   15

                    B. Data Collection and Analysis      ......................   16

                    C. Construction of Sediment Distribution Plots         ....... 18

                    D. Quantify Area of Inlet Influence       ..................  19

              RESULTS  ...................................................        21


                    A. General Sediment Distribution      .....................   21

                    B. Alongshore Sediment distributions       .................  23

                          1. Average Freauency of Occurrence       .............. 23

                          2. Three Point Moving Averages      ..................  25




                                               iii










            DISCUSSION  ................................................ 36


                  A. Area of Inlet Effect  .............................. 36

                  B. Summer vs Winter Sediment Distribution Patterns   ... 41


            CONCLUSIONS  ............................................... 43

            REFERENCES  ................................................. 45












































                                           iv










                                      LIST OF FIGURES

             Figure 1. Regional location map of study area     ............. 14

             Figure 2. Generalized shore-normal profile showing location

                   of ten sampling stations within three cross-shore

                   geomorphic zones  .....................................  20

             Figure 3. Shore-normal grain size plot showing average

                   frequency of occurrence of gravel, Band and mud

                   fractions within the three geomorphic zones    .......... 28

             Figure 4. Sand-sized frequency distribution of entire data

                   set plotted as a function of location north and

                   south of the inlet  ...................................  29

             Figure 5. Average frequency of occurrence of coarse,

                   medium and fine sand within the foreshore    ............ 30

             Figure 6. Average frequency of occurrence of coarse,

                   medium and fine sand within the shoreface    ............ 31

             Figure 7. Average frequency of occurrence of coarse,

                   medium and fine sand within the inner shelf    .......... 32

             Figure 8. Three point moving average of the coarse-,

                   medium- and fine-sand size frequeny data within the

                   foreshore  ............................................  33

             Figure 9. Three point moving average of the coarse-,

                   medium- and fine-sand size frequency data within the

                   shoreface   ...........................................  34

             Figure 10. Three point moving average of the coarse-,

                   medium- and fine-sand size frequency data within the

                   inner shelf  ..........................................  35



                                             v








            Figure 11. Idealized surficial    sediment distribution

                 map of coarse, medium and fine sand classes .......... 42















































                                         vi











                                  LIST OF TABLES

            Table 1. Summary of successful and unsuccessful summer

                 grab samples arranged according to transect and

                 station location ..................................... 26

            Table 2. Summary of successful    and unsuccessful

                 winter grab samples arranged according to

                 transect and station location ........................ 27
















































                                       vii











                                   ACKNOWLEDGEMENTS

                  Funds for this project were provided by the Department of

             Environmental Regulation, Office of Coastal Management using

             funds made available through the National Oceanic and

             Atmospheric Administration under the Coastal Zone Management

             Act of 1972, as amended. Matching funds were provided by the

             Sebastian Inlet Tax District.




















































                                          viii














                                      INTRODUCTION

                  It is widely accepted that most of Florida I s improved

             navigational inlets interrupt longshore sand migration and

             often promote accelerated erosion of down drift beaches (Dean

             and Walton, 1973; Jones and Mehta, 1980; Stauble et al.,

             1987). However, the magnitude and extent of erosion

             attributable to a specific inlet is generally unknown. In

             light of the recent Florida circuit court case involving the

             town of ocean Ridge and the South Lake Worth Inlet District it

             appears imperative that the "inlet effect" be quantified.



                  During the South Lake Worth Inlet hearings an expert

             witness testified that the first 2,000 ft of beach south of

             the inlet was in a state of critical erosion. However, the

             court ordered the Inlet District to initiate a restoration

             program along 2.5 miles (13,200 ft) of beach south of the

             inlet and a long term monitoring program to include a 10 mile

             area centered on the inlet. Because beach restoration projects

             stress natural and recreational resources and are always

             costly, the scale of such beach restoration projects should be

             limited to downdrift beaches documented to have erosion

             problems attributable to the presence of the inlet.



                 Attempts have been made to establish the degree to which

             an inlet contributes to downdrift shoreline erosion. These

             studies are usually based upon an analysis of a series of












             2

             aerial photographs or beach profiles (e.g., Foster and Savage,

             1989). In many areas however, an appropriate data set is not

             available (i.e., long term beach profile data) or the margin

             of error is very large (e.g., aerial photography; Smith and

             Zarill6, 1990).



                  This study was designed to establish the area of inlet

             influence   based    upon   surficial    sediment    grain-size

             distributions. Dean and Walton (1973) noted that inlets modify

             prevailing wave and current patterns and impound material that

             would otherwise drift along an uninterrupted segment of the

             coastline. Therefore, a distinct pattern of surf icial-sediment

             texture should be present in the.coastal areas proximal to an

             inlet that is distinguishable from distal areas. Tsein (1986)

             and Liu and Zarillo (1989) noted an increase in the mean grain

             size of surficial sediments in the vicinity of Shinnecock and

             Moriches Inlets (Long Island), although they did not attempt

             to spatially quantify the inlet effect.



                  In this study, it is hypothesized that ebb tidal currents

             at Sebastian Inlet jet fine-grained littoral drift seaward

             such that the surficial sediments proximal to the inlet are

             coarser than updrift (northern) areas or distal downdrift

             (southern) areas. The inlet effect will be quantified using

             closely spaced (1,000 ft) shore normal sampling transects.










                                                                          3


                                 GOAL AND OBJECTIVES

                  The goal of this study is to delineate the area of inlet

             influence using shore-normal and shore-parallel distribution

             patterns of selected grain-size classes within the foreshore,

             shoreface and inner shelf. To achieve this goal four

             objectives must be met:



                  (1) Design a sampling program of sufficient spatial

                       resolution,



                  (2) Collect and analyze sediment samples,



                  (3) Construct plots of cross-shore and longshore

                       sediment distributions,



                  (4) Delineate the area of inlet influence as revealed by

                       sediment distribution plots.











             4


                             BACKGROUND AND PREVIOUS WORK

                  A variety of methods have been employed to study the

             effects of physical processes operating on or within the

             coastal zone. The    most common methods included aerial

             photography, beach profiling, wave and current measurements

             and surficial sediment mapping. All of these methods vary with

             respect to time scale resolution, availability of data, cost

             and work effort required to collect and analyze the data.



                  Foster and Savage (1989) utilized aerial photography to

             document historic shoreline changes and predict future

             shoreline evolution. Available photographic data sets allow

             historical trends to be investigated, however the margin of

             error in estimating shoreline change is often large (Smith and

             Zarillo, 1990).



                  Beach profiles have been used by Aubrey (1979),, Bowen

             (1980) and Dean (1983) to examine seasonal shoreline changes,

             as well as the impact of storm events. While relatively

             inexpensive to collect, profiles are labor intensive and most

             regions lack profile data prior to the early 1970's.



                  Measurements of.currents, wind and waves have been used

             by Niedoroda and Swift (1981), Dally et al. (1985), and Fox

             and Davis (1976) to model and predict shoreline response to

             various physical conditions. However, reliable measurements











                                                                             5

             are costly and require considerable effort to obtain. Also,

             these measurements quantify instantaneous conditions which may

             not represent the long-term processes driving coastal sediment

             dynamics.



                  Surficial sediment distributions have also been used in

             the study of coastal processes. Pettijohn (1975) demonstrated

             that sediments contain valuable information regarding the

             depositional setting. Miller and Zeigler (1964) and Zenkozich

             (1967) concluded that although sediments are subject to

             temporal modifications such as seasonal changes, the general

             distribution patterns will remain unchanged. Thus, these

             patterns represent the equilibrium, time-averaged response of

             the sediment to shoreface hydrodynamics. In this study,

             surficial sediment distributions were chosen for analysis

             because (1) they represent long-term conditions and (2) the

             cost and work effort required for data collection are

             reasonable in light of the amount of information that can be

             deduced from the samples.



                  There are three primary factors that influence the

             characteristics of surf icial sediments in the coastal zone (1)

             sediment   source,    (2)  biologic    productivity   and     (3)

             hydrodynamic processes (Carter, 1988). The primary source of

             coastal sediment is terrigenous material which is ultimately

             derived from the weathering and erosion of continental rocks.











              6

              However, biogenic material may also be an important sediment

              constituent, particularly within the subtropical and tropical

              climatic regions of high carbonate productivity (Davis, 1978).

              For example, along the southeastern U.S. Atlantic coast there

              is a concomitant. decrease in quartz sand and increase in

              biogenic sediment from north to south (Milliman, 1972). This

              change reflects both increasing distance from the quartz

              source area and increasing carbonate production associated

              with the lower latitude climatic conditions (Gorsline, 1963;

              Giles and Pilkey, 1965). Localized terrigenous source areas

              (e. g. , eroding headlands) and productivity (e. g. , patch reef s)

              can also influence the characteristics of surf icial sediments


              in the coastal zone.



                   Hydrodynamic processes also inf luence nearshore surf icial

              sediment patterns (Komar, 1976; Davis and Ethington, 1976;

              Leatherman, 1979; Greenwood and Davis, 1984). These include

              shallow water waves, astronomic tides and oceanic circulation

              patterns.



                   Surficial marine sediment distribution patterns are

              generally mapped using the physical attributes of texture and

              composition. Visher (1969), Folk and Ward (1957) and Friedman

              (1967) concluded that the texture of natural sediment contains

              information regarding the source, mode of transportation and

              energy level of the transporting processes. The most common











                                                                           7

             method to resolve textural patterns utilizes grain-size

             frequency distributions whereby statistical (granularmetric)

             parameters such as sample mean, mode, sorting and skewness are

             used to characterize surficial sediments (Taney, 1961). Visher

             (1969) attempted to divide grain-size frequency distributions

             into subpopulations which he suggested were indicative of

             specific depositional environments (see also Bein and Sass,

             1978; Liu and Zarillo, 1989).



                  Mineral composition can also be used to quantify sediment

             distribution patterns and source area. In studies by Cherry

             (1965) and Judge (1970), heavy mineral analysis was used to

             determine the source of sediment along the California coast.

             Visual inspection of the surficial sediments within the study

             area suggest heavy mineral concentrations are less than one

             percent. Lenard and Cameron (1981) and Hoskin and Nelson

             (1971) studied the composition of rare carbonate beaches in

             Maine and Alaska in an effort to determine source and

             transport pathways.



                 Regional sediment distribution patterns along the east

             central Florida coast have been described by the Coastal

             oceanographic and Engineering Laboratory (1970, 1987), Field

             and Duane (1974), Meisburger and Duane (1971), and Ferland and

             Weishar (1984). The region's inlet systems have been described

             by the Coastal Engineering Laboratory (1965), Bruun et al.











             8

             (1966), Mehta et al. (1976), Davis and Fox (1981), Stauble

             (1988) and Coastal Technology Corporation (1988). These

             studies focused primarily on inlet geomorphology and

             hydrodynamics.



                  Bruun et al. (1966) constructed the first physical model

             of Sebastian Inlet in an effort to predict the effects of

             inlet stabilization on shoreline stability and inlet

             navigability. Mehta et al. (1976) examined the effect of the

             inlet on the economics, recreation, water quality and

             shoreline stability. Stauble et al. (1987, 1988) conducted

             research on sediment dynamics and the evolution of the flood

             tidal delta. Walther and Douglas (1991) presented data

             supporting the hypothesis that tidal inlets selectively remove

             fine-grained sediment from the littoral system. Studies by

             Wang et al. (1991, 1992) utilized a physical model designed to

             examine the effects of different jetty configurations on local

             hydrodynamics and sediment transport. Prior to the study

             presented herein however, no detailed investigation of

             sediment distribution patterns had been undertaken at

             Sebastian Inlet.











                                                                           9


                                      STUDY AREA

             A. Location and History

                  Sebastian Inlet (Figure 1) is one of f our inlets that

             interrupt the continuity of a narrow barrier island complex

             that separates the Indian River Lagoon from the Atlantic

             Ocean. It is located along the central part of Florida's east

             coast, approximately 45 miles south of Port Canaveral and 23

             miles north of Fort Pierce Inlet. The barrier island complex

             is composed of recent sediments which are underlain by the

             Pleistocene Anastasia Formation. Along portions of the open

             ocean shoreline, coquina rock outcrops occur just below mean

             low water. A narrow, sandy beach continuously borders the

             seaward side of the island.and a marshy lowland fringes the

             lagoon side. The barrier island rarely exceeds 1 mile in width

             or 20 ft in elevation (Meisburger and Duane, 1071).



                 Based upon a detailed history of the inlet compiled by

             Coastal Technology Corporation (1988), the first attempt to

             construct an inlet in the Sebastian area was made in 1886.

             Over the next 70 years the inlet closed, re-opened and shifted

             location numerous times. The present configuration was

             maintained after a major dredging operation in 1947-48 to

             establish a new channel. Since 1948, a series of dredging

             projects and jetty improvements have kept the inlet open in

             it's existing configuration. In 1970, the north and south

             jetties were extended to their present length. The south jetty











             10

             is a sand tight rubble mound structure. The north jetty, on

             the other hand, is a composite of the original rubble mound

             section built before 1955 and a pier structure supported by

             concrete pilings. The net southerly longshore drift entrapped

             by the north jetty has created an updrift offset. The strong

             flood tidal currents cause sediment to be transported through

             the inlet throat and deposited on the flood tidal delta. In

             1962, a sand trap was constructed at the western edge of the

             inlet channel to capture sediment entering the lagoon on a

             flooding tide. This material is then mechanically transferred

             to downdrift feeder beaches. This sand trap was dredged in

             1972, 1978, 1985 and 1989. Existing maintenance permits

             provide for sand transfer over the next 25 years.



             B. Hydrodynamics

                  Physical   conditions   at   Sebastian    Inlet  make    it

             hydrodynamically unique because the sides of the inlet are

             limited by rock. As a consequence the cross-sectional area is

             approximately one-half what would be expected if the inlet

             were free to enlarge, while admitting the existing tidal prism

             (Jones and Mehta, 1980). Consequently, the current through the

             inlet is exceptionally strong, causing sediment to be

             transported a considerable distance into and out of the inlet

             (Jones and Mehta, 1980).



                  The tidal range at Sebastian inlet is microtidal (less











             than 6.0 ft; Hayes, 1975). The spring tidal range is about 5

             ft in the offshore region and reduces to less than 1.5 ft in

             the lagoon (Wang et al., 1991). This reduction in range is due

             to the friction between the water and the rock lined throat

             section, as well as the curvature of the channel (Mehta et

             al., 1976). The phase lag between lagoonal high or low tide

             and slack water in the main channel is approximately 2 hrs.



                   Bruun et al. (1966) estimated the tidal prism of the
             inlet to be equal to 3.5 x    108 ft3 during spring tides. Tidal

             currents measured in the inlet throat section ranged from 6. 6

             ft/s on the flood tide to 5.0 ft/s on the ebb tide (Wang et

             al., 1991). Current velocities such as these keep the throat

             section free of sand since the currents are too swift to allow

             deposition (Mehta et al., 1976).



             C. Winds

                    The   prevailing    winds    at   Sebastian    Inlet    are

             northeasterly during the winter and east to southeasterly

             during the summer. Localized convective thunderstorms or

             tropical storms and hurricanes are characteristic of the

             summer and fall months. Thunderstorms generate winds with

             variable directions whereas most of the tropical storms and

             hurricanes follow tracks that are out of the southwest, south,

             or southeast, in order of decreasing frequency (Mehta et al.,

             1976).    Winter months are characterized by northeasters











              12

              generated by high pressure systems. These storms are usually

              more destructive than the tropical storms due to a larger

              fetch and longer duration (Mehta et al., 1976).




              D. Waves

                   Coastal Technology Corporation (1988) compiled a summary

              of available wave data which indicates that wave height and

              approach   are   dominantly    controlled by      local weather

              conditions. In the fall and winter months wave heights average

              4.5 ft and approach from the east-northeast. During the spring

              and summer months wave heights average 3.0 ft and approach

              from the east-southeast. During the passage of summer

              hurricanes and winter northeasters, average wave heights range

              from 6 to 10 ft. Wave heights greater than 10 ft occur only

              about 5 days a year.



              E. Littoral Drift

                   The net southerly littoral drift into the northern
              boundary of the study area averages.234,,000 yd   3 yr-1, of which
              1,300 yd3 yr-1 is removed from the budget via the accretion of
              updrift beaches (Wang et al., 1992). Approximately 75,000 yd      3
              yr-1 accumulates within the flood shoal complex and 6,800 yd3
              yr-1 is added to the sediment budget from the erosion of

              downdrift    beaches    (Wang    et   al.,    1992).    Therefore,
              approximately 164,500 yd.3 yr-1 or nearly 70% of the initial
              drift exits through the southern boundary of the study area by











                                                                        13

            natural sand bypassing processes.



                 On average approximately 60,000 yd3 yr-1 of sand is

            removed from the sand trap and mechanically transferred to a

            downdrift feeder beach. Thus, on average, there is a net
            sediment loss of approximately 9,500 yd3 yr-1 (approximately 4%

            of initial drift) in the vicinity of Sebastian Inlet.












                           14





                                                                                                                                                     Study
                                                                                                                                                     Area



















                                                              Indian River


                                                                                                            15M





                                                                                                                                  Atlantic Ocean






                                                                             Sebastian
                                                                                Inlet







                                                                                                                                           E



















                                    1 cm= 1 km
                                 Contour in meters


                               0         1         2 Miles
                                                                                                                                     .10



                                    0      WW Feet
                         Figure 1. Location map of study area which consists                                                         of a ten
                                    mile section of coastline centered at Sebastian Inlet,
                                    Florida. Ten sediment samples were collected along twenty
                                    seven shore-normal transects f rom mean high water to -42
                                    ft water depth.










                                                                          15


                                        Methods

                  In order to delineate the area of inlet influence using
             surficial sediment distribution patterns, the methods

             described below were employed to achieve each of the f our

             specific objectives described above.



             A. Design of Sampling Program

                  Determining the longshore and cross-shore limits of the

             study area was critical to the success of this project. Mehta

             et al. (1976) indicated that downdrift erosion occurred at

             least 2,000 ft south of the inlet. Clark (1989) identified a

             2.2 mile stretch of downdrift beach as an area of critical

             erosion. Work and Dean (in press) present data suggesting

             accelerated shoreline erosion is occurring along approximately

             3 miles of beach south of the inlet.




                  Therefore, based upon review of available published

             information and personal communication with a number of

             experts on coastal processes and engineering, a sampling

             program consisting of a ten mile section of coast centered on

             Sebastian Inlet was chosen for this study (Figure 1). This

             length exceeds the inlet effect limits suggested by the above

             mentioned studies.



                  Twenty seven shore-normal transects were established at

             f ixed DNR survey marker locations. Sampling transects were











             16

             spaced 1,000 ft apart within the first mile proximal to the

             inlet, thereafter transects were spaced    2,000 ft apart. This

             longshore sampling density is considerably greater than other

             surficial sediment    distribution studies conducted on the

             shoreface (c.f., Chauhan et al., 1988; Liu and Zarillo, 1989;

             TBien, 1986). Ten sediment sampling stations were established

             along each transect: mean high water, mean low water, the base

             of the beach face in the landward trough of the longshore bar

             and at depths of 6, 12, 18, 24, 30, 36 and 42 ft (Figure 2).

             This cross-shore sampling interval was designed to extend

             below the fair weather wave base (W. Dally, personal

             communication, 19 9 0) and therefore includes the zone of active

             sediment transport.



             B. Data Collection and Analysis

                  Surficial sediment samples were collected on two

             occasions representing summer and winter climatic conditions.

             The summer samples were collected over a ten day period in

             September,, 1991. The winter samples were collected over a

             fifteen day period in late April and early May, 1992. Along

             each transect a bathymetric profile was acquired using a Sytex

             depth recorder and LORAN C navigational system. The offshore

             samples were collected with a modified Ponar grab sampler from

             the R/V Phoenix. The penetration depth of the grab sampler

             is approximately 5 inches. This depth is considered adequate
             to include the maximum mixing depth of the surf icial shoref ace











                                                                              17

             sediments which are reworked under fair-weather hydrodynamic

             conditions (Stubblefield et al., 1977; Davis, 1985).

             Therefore, the surficial sediment samples collected during

             this study are assumed to represent a time-averaged seasonal

             cycle of erosion and deposition.        Intertidal and surfzone

             samples   were    collected   by   hand.    In   the    laboratory

             approximately 150 g of sediment were separated from each bulk

             sample using a sample splitter. Each sample was treated with

             3% hydrogen peroxide solution to reduce organic material

             content and then dried at 60 OC for 48 hrs. After drying, the

             samples were weighed and the bulk dry weight recorded.



                   Samples were then thoroughly wet-sieved to separate

             gravel (larger than 2mm or -1 phi) and mud (finer than 0.063mm

             or 4 phi). The sand and gravel fractions were transferred to

             separate beakers, dried at 60 OC for 48 to 72 hrs and weighed.

             The sum of the gravel and sand fractions was then subtracted

             from the sample's bulk dry weight to determine the mud

             fraction.



                  Approximately 2 g of the sand fraction was subjected to

             grain-size analysis using a custom built rapid sediment

             analyzer (RSA). This technique determines sediment grain size

             using an empirical equation derived by relating the fall

             velocity of sand grains through a fluid medium to the grain

             diameter (Krumbein and Sloss, 1951; Gibbs et al., 1971; Gibbs,












             18

             1974; Komar and Cui, 1984). The grain-size frequency

             distribution was recorded at 24 quarter-phi intervals between

             -2 phi (2mm) and 4 phi (0.063mm). The mean, standard

             deviation, skewness and kurtosis of the samples was then

             calculated. using the moments method (Friedman and Sanders,

             1978).



             C. Construction of Sediment Distribution Plots

                  To determine cross-shore trends in sediment size, plots

             of the relative abundance of gravel, sand, and mud were

             plotted as a function water depth. The northern and southern

             data were plotted separately.



                  The grain-size data obtained from the 24 phi size

             intervals was then grouped according to Udden-Wentworth sand-

             size classes (e.g., fine, medium, course),, Emery's (1960)

             geomorphic cross-shore zone (foreshore, shoreface, inner

             shelf; Figure 2) and proximity to the inlet. Plots of the

             average frequency of occurrence for each grain-size class were

             then constructed for each cross-shore zone. Three point moving

             averages of each grain-size class were also computed by taking

             the average of three adjacent data points and plotting that

             value at the position of the second data point. This method

             was used to smooth the data while preserving any significant

             trends (Davis, 1973).











                                                                          19

            D. Quantify Area of Inlet Influence

                   To establish the area of inlet influence the graphic

            depictions of alongshore and cross-shore grain-size data were

            visually inspected. A significant shift in the relative

            abundance of the grain-size data in the proximity of the inlet

            was interpreted to be a consequence of the inlet effect. The

            alongshore distance to this shift was then assumed to be the

            limits of inlet effect.











                20
                         Cross-Shore Sample Location
                            20-



                            10-
                                            MHW \Fore Shore
                                             MLW
                            0 . ................... SW ........ ...........................................................................
                                                   6
                           _10-                        12
                                                                   Shore Face
                       E                                   18
                       a   -20-                                 24
                       0
                                                                     30              @Inner @Sheff
                       W   -30-
                                                                            336
                           -40-                                                              42


                           -50 i
                            -1000                   1000       2000       3000        4000       5000

                                                       Distance from MLW (feet)

















                 Figure 2. Generalized shore-normal profile showing location of
                       ten sampling stations located within the three cross-
                       shore geomorphic zones.











                                                                          21


                                        RESULTS

                  A total of 246 "summer" samples were collected over a ten

             day period in September of 1991. A total of 222 "winter

             samples were collected over a fifteen day period in April and

             May, 1992. Tables I and 2 illustrate the location of

             successful and unsuccessful sediment grab sample recovery. An

             unsuccessful recovery is defined as any location where three

             attempts failed to collect a sediment sample.



             A. General Sediment Distribution

                  Figure 3 depicts the average frequency of occurrence of

             the gravel, sand and mud fractions for all samples plotted as

             a function cross-shore sample location. In both the summer and

             winter profiles, the sand-size fraction is the most abundant

             grain-size class. A typical bulk sample contains on average

             >90% sand-size material in the foreshore. Sand decreases in


             the offshore direction to minimum value of 50% at the seaward

             limits of the study area. The gravel fraction averages <10% in

             the foreshore and increases offshore to about 40%. Mud is the


             least abundant constituent as it is absent in the foreshore

             zone and gradually increases to about 10% on the inner shelf.



                 A textural transition zone occurs between -18 and -30 ft

             water depth in which there is a concomitant decrease in the

             abundance of sand and increase in the abundance of gravel and

             mud. This textural transition marks the shoreface-inner shelf











             22

             boundary (Meisberger and Duane, 1971) and confirms the

             successful sampling of the zone of active sediment transport.



                  Because the san d fraction is the most abundant grain-size

             class within the study area, granularmetric analysis focused

             on this fraction.    The average frequency of occurrence for

             each of the 24 phi intervals plotted as a function of location

             north and south of the inlet is presented in Figure 4. The

             bimodal abundances obtained during both the summer and winter

             sampling correspond to two of the three grain-size classes

             defined by Udden-Wentworth: (1) fine sand [A.0 phi to <2.0

             phi] and (2) medium sand [>2.0 phi to <-1.0 phi]. The fine-

             grained sand collected during this study is composed

             predominately of quartz, the medium sand is composed

             predominately of carbonate material. Coarse sand [ >-1. 0 phi to

             <-2.0 phi] was a very minor component of the surficial

             sediment and consisted entirely of carbonate material

             (shells).



                  There are slight differences in the shape of the
             frequency distribution curves for the data collected north and

             south of the inlet within both modes (Figure 4). These

             differences are minor (<2% shift) within each data set (e.g.,

             summer, winter) and the direction of the shift (e.g., finer,

             coarser) is not consistent between the two data sets. However,

             the variations between updrift and downdrift sand-size classes











                                                                         23

             suggests that the inlet is exerting an influence on the

             textural patterns of surficial sediment.



             B. Longshore Sediment Distributions

                  To further examine the apparent variation in grain-size

             distributions north and south of the inlet, the three sand-

             size classes (fine, medium, coarse) were plotted for the

             foreshore, shoreface and inner shelf zones as a function of

             longshore location. In this study, distances or locations

             north of the inlet are referenced using negative numbers

             and distances or locations south of the inlet are referenced

             using positive numbers



             1. Longshore Sand-Size Frequency Distribution

                 Figures 5, 6 and 7 are paired summer and winter plots

             depicting the average frequency of occurrence of coarse,

             medium and fine sand within each geomorphic cross-shore zone

             as a function of their proximity to the inlet.



                 Within the foreshore or intertidal zone (Figure 5)

             coarse, medium and fine sand show a fairly uniform

             distribution throughout the study area. In both the summer and

             winter plots medium sand is most abundant size class

             (averaging 90 to 95%), while fine and coarse sand are

             uniformly low (<10%). The distribution patterns are slightly

             asymmetric about the inlet with greater variability (ï¿½10%) on











             24

             the downdrift beaches. A comparison between the two profiles

             suggests the foreshore zone is slightly finer during the

             winter, especially on the downdrift beaches.



                  Within the shoreface or subtidal zone (Figure 6), fine

             sand is the most abundant grain-size class, although the

             spatial variability is high. Medium sand is of intermediate

             abundance and coarse sand is uniformly low (<2%). In both

             profiles, the southern locations exhibit greater variability

             than the northern locations. Although the spatial variability

             of fine and medium sand is high, a decrease in fine sand and

             a corresponding increase.in medium sand can be observed in the

             immediate vicinity of the inlet (approximately ï¿½4,000 ft) in

             both the summer and winter profiles. Also, between +6,000 and

             +14,000 ft (summer and winter) a significant decrease in fine

             sand and a corresponding increase in medium sand can be

             observed. In the winter profile, the appears to be a trend of

             increasing fine sand and decreasing medium sand towards the

             inlet. A significant coarsening of updrift beaches during the

             winter is apparent.



                  The most distinct longshore grain-size distribution

             trends were found on the inner shelf (Figure 7). In the summer

             data set, medium sand has the highest abundance in the distal
             portions of the study area (>+6,600 ft). In the area proximal

             (<+61000 ft) to the inlet the abundance of medium sand










                                                                          25


             decreases concomitant with an increase in the abundance of

             fine sand. The abundance of coarse sand remains very low (<2%)

             throughout the inner shelf. The winter profiles are similar to

             the summer except that the inner shelf area distal to the

             inlet (>+6,000 ft) does not grade into medium sand; it is a

             mixture of fine and medium sand.




             2. Three Point Moving Average

                  Figures 8, 9 and 10 are paired summer and winter plots

             depicting the three point average of the sand-size frequency

             plotted for each geomorphic cross-shore zone as a function of

             their proximity to the inlet. These plots are considerably

             smoother (less variability) than the average frequency plots

             although the general trends (discussed above) in the data Bet

             are preserved. Inferences regarding the area of inlet

             influence will be based upon these figures.

















                                                                                                             Ch


                                             GRAB SAMPLE RECOVERY TABLE


                       Sample                             Summer
                       Depth

                       42 o o o o o o o o o o o o o o           0 0 0 0 0 0 0 0 0 0 0 0         0

                       36 o o o o o o o o o o o o o o           0 0 0 0 0 0 0 0 0 0 0 0         0

                       30 o o o o o o o o o o o o o o           0 0 0 0 0 x x 0 0 0 0 0         0

                       24 o   o  x   x o o o o o o o o o o      0 0 0 0 0 x x x   x   x  0  0   0

                       18 o   01 x   0 0 0 0 0 0 0 0 0 0 0      0 0 0 0 0 x x x   x   0  x  x   0

                       12 o   o  o   o o o o o o o o o o o      0 0 0 0 0 x x x   x   0  0  x   x

                       6   o  o  o   o o o o  o o 0 o  o 0 o    0 0 0 0 0 0  0 x  x   0  0  0   0

                       Sw  0  0  0   0 0 0 0  0 0 0 0  0 0 0    0 0 0 0 0 0  0 0  0   0  0  0   0


                       LT  o  o  o   0 0 0 0  0 0 0 0  0 0 0    0 0 0 0 0 0  0 0  0   0  0  0   0


                       HT  o  0  o   0 0 0 0  0 0 0 0  0 0 0    0 0 0 0 0 0  0 0  0   0  0  0   0

                          -25  -20    -15    -10  -5         0          5    10   15     20     2.5

                                          LONGSHORE DISTANCE    (x1,000  feet)



            Table 1. Summary of successful and unsuccessful summer grab samples arranged according
                  to transect and station location. Successful grabs are denote by "o" and
                  unsuccessful grabs are denoted by "x".












                                            GRAB SAMPLE RECOVERY TABLE


                       Sample                          Winter
                       Depth

                       42 o o o x o o x o o o o o      o   x 0 0 0 0 0 0 0 0 0 0 0 0        x

                       36 o  x   o  o x o o o o o o o  o   0 0 0 0 0 0 x 0   0  0   0  0  0 0

                       30 o  o   o  o o x x o o o o o  o   0 0 0 0 0 0 0 0   0  0   0  0  0 0

                       24 o  o   o  x x o o 0 0 0 0 0  0   0 0 0 0 0 x x 0   0  0   0  0  0 0

                       18 x  0   o  o x o x o o o o o  o   0 0 0 0 x x x x   x  0   0  x  0 0

                       12 o  o   x  o o o o o o o o o  o   o o o x o x x x   x  x   o  x  x x

                       6  x  x   o  o x o x o o  o x o o   x 0 0  0 0 x 0 0  x  0   x  x  x 0

                       SW 0  0   o  o 0 o o o 0  o o o o   x 0 0  0 0 0 x x  0  0   0  0  0 0


                       LT o  o   o. o o o o o o  o o o o   x 0 0  0 0 0 0 0  0  0   0  0  0 0


                       HT o  o   o  o o o o o o  o o o o   x 0 0  0 0 0 0 0  0  0   0  0  0 0


                         -25   -20   -15   -10   -5      0         5   10    15     20     25

                                         LONGSHORE DISTANCE (x1,000 feet)



            Table 2. Summary of successful and unsuccessful winter grab samples arranged according
                  to transect and station location. Successful grabs are denote by "o" and
                  unsuccessful grabs are denoted by "x".






                            28                                             SUMMER GRAVELSAND:MUD
                                                                                                      ALL STATIONS

                                                         100-
                                                         90  . ...............    .....
                                                                                                .............        .........*........            ........


                                                                                                                            . . .............................................
                                                         80  . ................................................................................ ................ ..
                                                         70  . .....................................................................................................................
                                                  Z
                                                  U'     60  . ........................................................................................................... . ........ . ......  ................
                                                  cc
                                                  Ri     so-
                                                  ln@    40_..F0RESH(TRE.J._                                 ............................................
                                                               ................... ................................... @T@@tj         ...       ,0
                                                         30  . ............................................................................................................................... ............
                                                         20  . ............................................................................................................... .an ..................................

                                                                                                                                  ..........
                                                         10                    ......... ... ............................ 101; . .......... . .....................  ......
                                                             0
                                                                          0                -6       -12     -18       -24     -30 . -i6         -4,2
                                                                                          SAMPLE ELEV./DEPTH


                                                                         ......  GPIAVEL       ........... SAND             MUD


                                                                          WINTER GRAVEL:SAND:MUD
                                                                                                    ALL STATIONS

                                                       100   . ..........
                                                         90  . ...................................................................... . ........... ................... . ...... . ...........................
                                                         so  . ..................................... . .......................... . .................................. @!"' ..... . .......................................

                                                         70  . ...................................................................................................... .... .....I..................I......... . ..
                                                 Z                                                                                '" - -I.
                                                 W                                                                                7777_.,    . ..........
                                                         60  . ............ ................................... . ........ . .................... . .............. . . . . . ........ . ...  .....
                                                 cc
                                                 Uj      so  . ..............   ------------------------------------------------------------ - -------------- - -------- --
                                                                                                            qk                           I INNER SHELF
                                                         40-               ................. . ........ . ........... Rtiqagm . .............. . . . ...
                                                         30  . .......................... . . . .......... . ......... . ........ . .................... . ......... .............. . ...................  _71 .... . . . ....
                                                                                                                                  0....... 00.
                                                         20  . .......................... ................................... ........... . . . ........... . . . ............. ;.P.^ ---- ------- ---
                                                         10  . ........... . ................... . ....                                   . ............... .....


                                                                3        0        -3       -6       -12 -18 -24 -30 -36 -42
                                                                                          SAMPLE ELEL./DEFrH



                                                                                 GRAVEL ---- SAND                           MUD




                            Figure 3. Shore-normal grain-size plot showing average
                                       frequency of occurrence of gravel, sand and mud fractions
                                       within the three geomorphic zones. Summer prof ile is
                                       shown in top panel, winter profile in bottom panel.






                                                    SUMMER DISTRIBUTION                                                                                    29
                                                                SAND SIZE FRACTION


                                            14  . ........................... I............................................................ ................. .......................................
                                                   CMARSE 84D
                                            12  . .......................... ...................... .................................. .............  .................
                                       d    10  . ................;........................................................................................................ .....  .........................
                                       LU
                                       cc
                                       LL                                                             ............................ ............... . ..................
                                                . ........................................................................................


                                                6. ................................................................................................................ ......................

                                                4. .......................................... ............. ... ............ .................................. .........
                                                01 .......     ........... .... ................. ......       ....... .................. .......
                                                  2 -1.5 -1 -0.5 0                   0.5            1:5              2 5          3'6
                                                                                            PHI




                                                                                NOUH        ------  SOUTH


                                                  WINTER DISTRIBUTION
                                                             SAND SIZE FRACTION


                                                                   ...................... ..........................................  ;:@7 . . . .1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
                                           12-                  ....................        ............................... .......  .....................
                                     0     10   . ...................................................... . ......................................................................... . ....... . ...........
                                     W
                                     cc
                                                                                                               ...... . ......./. ..........  ................
                                     U.     8   . ................................................... . ..
                                            6   . ....................................................... ---**-, .. ........................ .. . .......... .Z..... ......... . ......  \11

                                            4   . ................ . .................................. . . . .....  ...................................... .. . ....... ...... ...................


                                                       ............................... ...  ................................................ . ... . .........................................
                                            2   . .............
                                            0-                                      0.'6            1 : F> ' 2' '26        3      3'6
                                                -2 -1.5 -1 -0.5
                                                                                            PHI



                                                                                  North     ------  South




                           Figure 4. Sand-size frequency distribution of entire data set
                                      plotted as a function of location north and south of the
                                      inlet. Boundaries of three sand-size classes, as def ined
                                      in this study, are also                                  indicated. Summer profile is
                                                                                                  ..................


                                                                                                ..................................... ........... 11 .. ...............


                                                                                                                                  .. ..........
                                                                                                ................................. .....................
                                                   ...................................... ... . ..........           . .........................  @11

                                                   ..............
                                                                                                 .................................................................


























                                      shown in top panel, winter profile in bottom panel.







                              30                                               SUMMER FORESHORE
                                                                    AVERAGE FREQUENCY OF OCCURRENCE
                                                                100-                                                                        %
                                                                               *............
                                                                .90 . ............................................................................. . ................................ :X.,c ............... '.'.'n%  ............
                                                                so  . .......................................................................................................................................................
                                                                70  . ........................................................................................................................................................
                                                                60  . .................................................................................................................................... . ..................
                                                        LU
                                                                so  . .......................................................................................................................................................

                                                                40  . ...............................................................  .......................................................................................
                                                                30  . ..............................................................................  ........................................................................
                                                                20  . .......................................................................................................................................................
                                                                10  . ...............................................................................................................  ........

                                                                    0        1             -
                                                                    30 -25 -@o -@6__ -40 4                           6       6       10 1'5 iO i5 30
                                                                                         LONGSHORE DISTANCE (x 1,000 FT.)



                                                                                        COARSE         ........... MEDIUM - FINE


                                                                               WINTER FORESHORE
                                                                    AVERAGE FREQUENCY OF OCCURRENCE

                                                              100-
                                                                                      .. . ... -__% "o   ..............I......
                                                                90  . .....................I.......................... :@'@ ............................. . ........ 4en . .....  ..............
                                                                                                                             %. i         V
                                                                so  . ............................................ ................................................  ........................................................
                                                                70  . ...... . .............................. . .... ..................................................................................  ........................
                                                                60  . ........................................................................................................................................... . ..........
                                                       LU
                                                       cc       so  . ..................................................................................... . . .I.......................................................... .
                                                                40  . ......................................... . ........... . . . ...................... ....... . ........................................ . ..................
                                                                30  . ............................................ . . ............................................................................................ . ..........
                                                                20  . ................................ . ......... ................................................ ..................... . ................... ..............
                                                                10  . ............................................. ........... . . . ................... ....... ......  ..... ....... ............. .........

                                                                0
                                                                    iO -iB -iO -i5 -iO 4                            6       6       10 16 iO 26 30
                                                                                        LONGSHORE DISTANCE (x 1,000 FT.)



                                                                               ...... COARSE          . .. . ..... MEDIUM*- FINE





                              Figure 5. Average frequency of occurrence of coarse-, medium-
                                          and fine-sand classes within the foreshore. Summer
                                          profile is shown in top panel, winter profile in bottom
                                          panel.






                                                             SUMMER SHOREFACE                                                                                31
                                                   AVERAGE FREQUENCY OF OCCURRENCE

                                              100-

                                               90  . ...... ......................... ................................................................................. . ..............................

                                               80  . ............................ ...... ....... ....................... ........................................... .......  ..........................

                                               70  . ........................... ......... ..... .... ......... . . ........ ..... ........... ... .............  ....... ..............
                                        d      60  . ...............  ..........................
                                                                                          .......... ........
                                                                                                            ..... ........ ................... ................
                                        LU
                                        a:     5o  . ..................... . ............................................. ..... .......... .................  .......................  ...........
                                        LL                                                           *                               .
                                                                                                     . ..4?. . ........ . .....................i....  ........
                                               40  . ..............   ........................... i;  ..............

                                                                                                                     .. ...............  ...................
                                               30  . ...................  _.- ......... -@*@"% ... ... . ........ . .... ............. -----

                                                        ......................            ........
                                               20  . ......           i...... ...................... .......... . . ............. ...........%.........  ........................
                                               10  . ............................... @'l ........................I...................................................... .
                                                                                                                             ...............

                                                 01
                                                   -60 -@5 -io -15 -10 -5                            0 5     1b      i's io 2,5 30
                                                                      LONGSHORE DISTANCE (x 1,000 Fr.),



                                                              ......  COARSE       ........... MEDIUM



                                                             WINTER SHOREFACE
                                                   AVERAGE FREQUENCY OF OCCURRENCE

                                              100-
                                               90  . ................................................................................. ...................................................... ............

                                               80  . .............................................................................. .... ............................... ................... ............
                                               70  . ............... . .............................................. ... ....... ....... ...................I..... .. ...........  ?3;;-: ............
                                                                .. ........... .. ................ ....... ................ ............. . ..%. ....... ... ;r  ......................
                                        (3     60  . .....................
                                        W
                                        Cc     50  . ........... ... . . ..... .......  .................... **'**'* ............. ..... ..........  ............ ............
                                        LL                                          ........
                                               40  . ....................... ........... .. ................%....... 3r; .............. .... ....  ........
                                                                                                                           ... ..........
                                               30  . ...............................................................;... ....... ....... ....... ..... . ......j.......... ... ........
                                                                          ...........................          .. .. .........i ..............................
                                               20  . .....................................           ........... ........ .....
                                               10  . ................................................................................w..................................................................
                                                 01
                                                   -30 -25 -20 -16 -10 -5                            0 5     10 15 io 25 30
                                                                      LONGSHORE DISTANCE (x 1000 FT.)



                                                             ......   COARSE      ........... MEDIUM - FINE





                            Figure 6. Average frequency of occurrence of coarse-, medium-
                                        and fine-sand classes within the shoreface. Summer
                                        profile is shown in top panel, winter profile in bottom
                                        panel.






                            32                                        SUMMER INNER SHELF
                                                              AVERAGE FREQUENCY OF OCCURRENCE

                                                         100-

                                                                                                                          ............ ........ P% ...................................
                                                         90   . .......................................1.. . ............. .. ....... .........
                                                                                A
                                                                                  ............ .... .V ........ ... ...... . ............ ......E....... . ...........
                                                         so   . .................... .... .....

                                                                                                                                 ......................................
                                                              . ....................V.......... . . . ....... .... .... .. "j
                                                         70
                                                  d      60   . ......................................................... . ...... ......... ..... ...........
                                                  LLI
                                                  cc     so   . .......................................................... ... ................. .. ...........................................................

                                                         40   . ......................................................... ...... . ..........a...... ............. ........................................
                                                                                                            A

                                                                                .................. .... ....... ...... .. .... .......... ... .......................................
                                                         30   . ..............................              :"
                                                                                        . ....  .........   ... I ......U
                                                         20   . .......................... ... ...........       ... ...... ....... ..... .......
                                                         10   . ........................ ........... ..... ......... ......... . .. TV .... .....*... . ......  .........
                                                              01
                                                              -30 -25 -20 -15 -10 -5                        0    5        10 15       20 25          30
                                                                                LONGSHORE DISTANCE (x 1,000 FT.),



                                                                        ......  COARSE        . .........   MEDIUM - FINE


                                                                        WINTER INNER SHELF
                                                              AVERAGE FREQUENCY OF OCCURRENCE

                                                         100-
                                                         90   . .................. .......  .........................L
                                                                                                            . . ...... .......... ............t..................... . ..........  ..........

                                                                                                            . . ............... ....... . ................  ..................
                                                         so   . .................

                                                                                              .... ... ...........
                                                         70   . ................ -- - - - ---------------  ---- ... ........ ... ..... ...... ---- ------  ....................
                                                  a      60   . ............... f..........................               A ...... . ...... . . ....................
                                                                                              . .... ................... . ......

                                                  cc     so   . .............. ------------------------     .. ......... . ........ **"* ... .....  .... . ........ .. ............. . .......
                                                         40   . ...............  ...... .......... . ............... ................. . ....... .... .....
                                                                                                                                         . ...... . .............


                                                                       .. .... .. ....... . ..... . ........ ... ... .................. . ...... .. . .. ...................
                                                         30   . ..............

                                                         2
                                                              0-                                            . ..............;..... . ............
                                                                                                                                    7
                                                         10   . .................. ........                      .... ....... .. .......... . ....... . ..........  ..............

                                                              0- -------
                                                              -30 -26 -20 -15 -10 -6                        0             510 15       20 26           30
                                                                                 LONGSHORE DISTANCE (x 1000 FT.)



                                                                         ...... COARSE        . ... . ...   MEDIUM -FINE






                           Figure 7. Average frequency of occurrence of coarse-, medium-
                                      and fine-sand classes within the inner shelf. Summer
                                      profile is shown in top panel, winter profile in bottom
                                       panel.






                                                             SUMMER FORESHORE                                                                              33
                                                   AVG. FREQ. OF OCCURRENCE (3 PT AVG)
                                              100-

                                               90  . ..........................................I....................................................................................... . ....................

                                               so  . ........................................................................................................................................................
                                               70  . ........... . ...........................................................................................................................................

                                               60  . .......................................................................................................................................................
                                        LU
                                        cc     so  . .......................................................................................................................................................
                                        U_
                                               40  . .......................................................................................................................................................
                                               30  . .......................................................................................................................................................
                                               20  . ..................................... ......... ......_ ................... .......... . ...............  ...............................................
                                               10  . .......................................................................................................................................................

                                                   0
                                                   30 -@5 -20 -15 -10 -5                        0      5      10 15 20 25 30
                                                                      LONGSHORE DISTANCE (x 1,000 FT.)



                                                             ......  COARSE       ........... MEDIUM


                                                             WINTER FORESHORE
                                                   AVG. FREQ. OF OCCURRENCE (3 PT AVG)
                                             100-           *...
                                              90   . .............................................................................  ............. ............

                                              so   . ....................................... . .................................................................................................. ............
                                              70   . ........................................................................................................................................................
                                       d      60   . ............................................................................................................. . ....... . ...............................
                                       LU
                                       cc     so   . ........................................................... . ......................................... . ....... . ............................. . .......
                                       U_
                                              40   . .................................................................................................................................... . .................
                                              30   . ...................... . .......................................................... . ..................... .............................................

                                              20   . ............................ ........................................ . .... . ....................... . ................. . ..............................
                                              10   . .............................................. . ................................ ........  ......................................

                                               0
                                                   30 -26 -@o 46 -iO                           6     i      110 I'S 20 26 30
                                                                    LONGSHORE DISTANCE (x 1,000 FT.)



                                                            ...... COARSE               MEDIUM - FINE






                          Figure 8. Three point moving average of the coarse-, medium-
                                      and fine-sand size frequency data within the foreshore..
                                      Summer profile is shown in top panel, winter profile in
                                     bottom panel.






                          34                                          SUMMER SHOREFACE
                                                             AVG. FREQ. OF OCCURRENCE (3 PT AVG)
                                                        '100-
                                                             90 . ........................................................................................................................................................

                                                             so . ............................  ...............................I.......................................................................................
                                                             70 . ....................... .............  .................. ... ........... .. ..............I...... ... .. ...................................

                                                                                                                     . ........
                                                 d           60 . ........... .... ................................................. ....... ..... ... . . .. ..........................................
                                                 Uj
                                                 cc          50 . ...........a ........................................................... . ............*.............. ............................................
                                                 LL
                                                                                          .....................      .... .. .......... ...Z
                                                             40 . ...............                                            ...........................................
                                                             30 . .................... . 1Z .................. -`-  ....... .........I.. .......... .........-................
                                                                                                                                       v-
                                                             20 . ........................... @V  .................................................I..................................................................
                                                             10 . .......................................................................................................................................................

                                                             0      ,              i
                                                             30 -25 -20 -`15 -10 -6                      0           5       10 15 iO iS '30
                                                                                LONGSHORE DISTANCE (x 1,000 FT.)



                                                                       ......   COARSE       ........... MEDIUM - FINE


                                                                         WINTER SHOREFACE
                                                                AVG. FREQ. OF OCCURRENCE (3 PT AVG)
                                                             100-
                                                             90 . .................. ....... ........ ......-........ *** ....... .........*......... .......

                                                             80 . ..........................*........ ..... ** ...* ....... ** ........ *** ...... '** ... *** ....... -* ........ -* ......*.........  -* ..........
                                                    ZE       70 . ........... . ................................... ............ . .... .......... .................................................................
                                                    d        60 . .................................................... ............................... ......... ...... .........P..........................
                                                    W
                                                                                   . ................................ . ...... . ... ........ ........... ...............................
                                                    cc       so . ..............
                                                    LL
                                                             40 . .................................................... . ................................ . ........ .......... !!..; ...... ...........................
                                                             30 . ...................................... . ....................\... . ....:...............................I............... .................
                                                             20 . ................................ . ... . .... . .. . ..........................i.......................................... ...... . ...............
                                                             10 . .................... . . . ................ ..................... . ................................................... . .................................
                                                             0.       1         1 ----------             ---         I                 _U __9F ...1
                                                                30 -25 -20 -iS 40 -6                                 05      10 15 20 25 30
                                                                                LONGSHORE DISTANCE (x 1000 FT.)



                                                                                COARSE                   MEDIUM - FINE





                          Figure 9. Three point                            moving average of the coarse-, medium-
                                                                                             ......... .. ........   .....   .....
                                                                         /0"*N                                               . . .........
                                                                          ....................................................................... .i............... .......

                                                                      . . ................................................. ...... . .. ......... ---- ----------
                                                                      ....... ................ _.  ............ . .............  @.; .. ............ ............ ...





                                                                         .................................. ........... . ... ......... .............................. ...............


                                                                         ...................................... .............................. ........ :I .......... ........
                                                                                         ................................ . ..... . .i.. ....... . ........... .............
                                                                         ...................................... . .......................................... ....... @-! .. . ..... .........

                                                                         ........................ . ................... . ...... :@ .... . ... . ........ .....................................


















                                     and fine-sand size frequency data within the shoreface.
                                     Summer profile is shown in top panel, winter profile in
                                     bottom panel.






                                                              SUMMER INNER SHELF                                                                           35
                                                   AVG. FREQ. OF OCCURRENCE (3 PT AVG)
                                                   100-

                                                   90 . ..................................... __ ......_...................... __  ............... __ ............  .............................................
                                                   so . .............. 1W  ......... ".1.% ................. .. .......................t.................................
                                       pq          70 . ...............................................%........... .................. .........;..............................................I .............
                                       d           60 . ...............................................   ........................I.....................................
                                       W
                                       a:          6o . ........................................................ .......................... ..............................................................
                                       U_
                                                   40 . ...............................................  ......... . ...............................................................
                                                   30 . ............................................... ...q...... ............................................................

                                                   20 . ............................................ ................... V_@  .................... .... ........................................
                                                                                          V
                                                   10 . .................................. ....................................................-...........................................
                                                              ..............
                                                   01     1      1       1                                                    1
                                                   30 -25 -20 -16 -10 -5                      0           6 10 15 20 25 30
                                                                     LONGSHORE DISTANCE (x 1,000 FT.).



                                                              ......  COARSE              ........... MEDIUM



                                                              WINTER INNER SHELF
                                                   AVERAGE FREQ. OF OCCURRENCE (3 PT AVG)
                                                   100-

                                                   90 . .......................................................................  ........ .....................................................................
                                                   so . .................... .. ........  r............. .................. ..................................................................
                                                   70 . ............... J
                                                              ..........................  .......... .................... ......0............................... jr ........................

                                       CY          60 . ......................................................
                                                                                          ...... ...................... ............... ....... ...... . ...........................
                                       W
                                       cc          50 . ......................................................... ............................. ................. ...............................
                                       U_

                                                                                              ............... .............
                                                   40 . ..................................................... ...... @;k-.1,; ..... ............................
                                                                                          Z

                                                        .... . ..................................-.......  .............. . ...................................0..................
                                                   30 . .........
                                                   20 . .................. . ............ ......................i.................i................................................................
                                                   10 . ........................................................................ ......... ...................................................................
                                                   01
                                                   -30 -25 -20 -16 -iO 4                      0           5 10        I'S iO 25 30
                                                                     LONGSHORE DISTANCE (X 1000 FT.)


                                                              ......  COARSE              ........... MEDIUM  Fi@E
                                                              ............
                                                                                                            .........
                                                                                                                 .........
                                                              .............. . ............ P"            .............................
                                                              ................................. ........ ..................I...... ...........................
                                                                                          _- t -.-
                                                              ........................... ............... .. .. .................... ... ..........
                                                              --------------- ... ..............................  .................. ............................

























                                                              ................................. ......
                                                              .......................................... ............................
                                                                                          . . . ....................................... .......
                                                              ....................................... .....I-         -
                                                              ................................. .........I................... . .......................................

                                                                         ... ...................... .
                                                                                          I @..................i........................................




                          Figure 10. Three point moving average of the coarse-, medium-
                                     and fine-sand size frequency data within the inner shelf.
                                     Summer profile is shown in top panel, winter profile in
                                     bottom panel.











             36


                                      DISCUSSION


             A. Area of Inlet Effect

                  The cross-shore distribution of gravel, sand and mud

             recognized during this study (Figure 3) correlates well with

             the sediment distribution patterns documented on Florida's

             shelf by Meisburger and Duane (1971). It is also consistent

             with the erosional shoreface retreat model of a transgressive

             barrier island system as presented by Swift et al. (1971).



                  The foreshore, located between mean high water and mean

             low water, is a high energy zone, dominated by the swash and

             backwash of breaking waves (Komar, 1976). Within the study

             area it is characterized by a high concentration of coarse and

             medium sand, as well as a relatively high (10%) concentration

             of gravel. Mud is scarce (<2%) within this zone.



                  The shoreface extends 2,500 ft seaward of the foreshore

             to a maximum depth of approximately 30 ft. Fine sand is the

             most abundant sediment type in this zone, which is dominated

             by wave driven f low associated primarily with shoaling waves.

             The asymmetry of shoaling waves leads to differential net

             transport. This favors the onshore migration of larger

             particles and the offshore movement of finer material,
             generating a graded textural pattern (Carter, 1988). This is
             confirmed by the abundance of coarse and medium sand within

             the foreshore and the abundance of fine sand within the











                                                                          37

             shoref ace. Coquina outcrops occur within this zone, providing

             a local source of coarse- and medium-sand sized shell

             material.




                  The inner shelf is located seaward of the modern sand

             prism in water depths greater than approximately 36 ft. The

             inner shelf is a low energy zone characterized by a decrease

             in the abundance of sand and an increase in the abundance of

             gravel (up to 40%) and mud (up to 10%). The gravel and mud

             deposits are primarily produced during erosional shoreface

             retreat (Civil, 1990) although modern biological productivity

             contributes some coarse-skeletal material to these palimpsest

             beds (Swift et al., 1971). Therefore the inner shelf gravel is

             comprised of both relic broken, bored and oxidized shell

             material as well as modern, well preserved shell material.



                  The three geomorphic cross-shore zones are oriented

             parallel to the shoreline throughout the study area except in

             the vicinity of the inlet (Figure 11). In this area, a lobe of

             fine-grained sand approximately 10,000 ft wide and centered on

            .the inlet protrudes 4,000 ft out from the shoreface and into

             the inner shelf zone. In addition, a 6,000 ft wide zone of

             medium-grained sand protrudes approximately 3,000 ft out from

             the foreshore and into the Bhoreface zone. The presence of

             these seaward protruding sediment lobes, identified on the

             basis of grain size, is consistent with the tidal jetting











             38

             hypothesis presented above. The lobe of fine-grained sand is

             a direct effect of the strong tidal currents which jet this

             material out from the shoreface and onto the inner shelf.

             Fine-grained sand is also selectively transported into the

             inlet where it accumulates within the flood shoal complex

             (Stauble et al., 1987). The medium-grained sand lobe

             identified within this area is interpreted to be a lag deposit

             of slightly coarser material not mobilized by tidal jetting-



                  If this fine-grained sand is jetted seaward and deposited

             below wave base or just within wave base it may not return to

             the shoreface or, if returned, the process may be very slow

             (Dean and Walton, 1973). Based upon the sediment budget of

             Wang et al. (1992) the loss of littoral drift to the inner

             shelf appears to be insignificant. Therefore, most fine-

             grained sand deposited on the lower shoreface and inner shelf

             must be migrating landward at the same rate as it is being

             jetted seaward.



                  Tidal currents are not 100% effective in winnowing fine

             sand from littoral drift. Between +3,000 and +5,000 ft the

             abundance of fine-grained sand on the shoreface is equivalent

             to updrift shoreface values (Figure 9). This zone corresponds

             to the location of the shore connected ebb shoal. Athough the

             crest of the shoal is comprised of medium-grained sand

             (Parkinson, 1990) the flanks and surrounding area are










                                                                          39

             blanketed with fine-grained sand. Studies conducted by Hubbard

             (1975) and Dean (1988) have suggested that the presence of a

             shore connected ebb shoal is indicative of the effective

             transfer of littoral sediment across the inlet opening.

             Therefore, based upon the distribution of medium-grained sand

             on the shoreface and the location of the shore connected ebb

             shoal, approximately 6,000 ft of downdrift shoreface is

             directly affected by inlet hydraulics.



                  Within the shoreface area extending approximately +6,000

             to +14,000 ft, a reduction in fine-grained sand and

             corresponding increase in medium-grained sand is observed

             (Figures 9 and 11). Outcropping coquina of the Anastasia

             Formation occurs in this area and this material may be

             providing a local source of medium- and coarse-grained sand to

             produce higher abundances of these grain-size classes. The

             outcrops could also cause localized turbulence (breaking

             waves) which may winnow and remove fine-grained sand from the

             area. A similar sediment coarsening is observable at

             approximately -20,000 ft. This area also hosts outcropping

             coquina rock (Figure 11). The presence of coquina rock may

             also be responsible for the greater degree of grain-size

             variability noted in the foreshore and shoreface cross-shore

             grain-size plots (Figures 5, 6, 8 and 9).



                  The presence of outcropping coquina rock within the











            40


            shoreface zone south of the inlet has been attributed to the

            inlet and it's influence on the littoral sediment budget. Wang

            et al. (1992) have indicated that significant downdrift

            shoreline erosion (averaging 5 ft per yr) occurred between the

            years 1947-1970. This erosional interval is attributed to the

            reopening and stabilization of the inlet in 1946. However,

            between the years 1970-1986 downdrift shoreline erosion slowed

            to an average of 1.5 ft per yr (Wang et al., 1992). This

            reduction in the rate of shoreline retreat and the development

            of a stable (Wang et al. , 1992) shore connected ebb shoal

            strongly suggests the inlet has reached a state of equilibrium

            in which most of the littoral drift effectively bypasses the

            inlet opening.



                 Beyond +14,000 ft, the abundance of fine sand in the

            shoreface zone increases and is similar to values observed

            north of the inlet (Figure 6 and 9). This increase is probably

            the result of (1) onshore return of fine-grained sand jetted

            out onto the inner shelf and (2) the absence of coquina

            outcrops, which locally coarsen the surficial sediments.



                 The area of inlet effect can also be estimated using the

            inner shelf data. Based upon the surficial sediment grain-size

            distributions obtained from this zone during the both the

            summer and winter the area inlet influence appears to be

            approximately ï¿½5fOOO ft (Figures 7 and 10).











                                                                          41


             B. Summer vs Winter Sediment Distribution Patterns


                  Because the east-central Florida coastline is wave

             dominated, a comparison was made between winter and summer

             seasons to determine whether the inlet effect persists

             throughout the year or is masked by a strong seasonal signal

             (e.g., winter storms). Variations in the grain-size data which

             can be attributed to the inlet are present in both of the data

             sets. Therefore, the inlet effect is not masked by winter

             storm conditions although the textural pattern of surficial

             sediments is modified. During the winter the updrift distal

             shoreface coarsens while the downdrift distal inner shelf


             fines. These shifts are consistent with seasonal.cross-shore

             sediment transport (Komar.,, 1976). A coarsening of the

             shoreface would generate a surplus of fine-grained sand which

             could accumulate in downdrift (southern) inner shelf areas.











            42



                                              04;V 9 A





























































            Figure 11. Idealized summer surficial sediment distribution
                map of coarse-, medium- and fine-sand classes. Map is
                 representative of both summer and winter conditions.











                                                                         43


                                      CONCLUSIONS

                  (1)     This study has demonstrated that textural

             distribution patterns of surficial sediments can be used as a

             method to delineate the area of inlet influence. Within the

             Sebastian Inlet area the presence of coquina rock outcrops in

             downdrift areas proximal to the inlet has resulted in highly

             variable grain-size distribution patterns which have hampered

             quantification of the area of inlet effect.



                  (2) The hypothesis that strong tidal currents jet fine-

             grained sediment offshore is supported by the decreased

             abundance of fine-grained sand within the shoreface and

            .increased abundance of fine-grained sand on the inner shelf

             adjacent to the inlet as well as within the flood-shoal

             complex.



                  (3) The grain-size surficial sediment distribution

             pattern within the study area suggests the area of inlet

             influence within the shoreface is approximately -5,000 ft

             (updrift) to +6,000 ft (downdrift). Inner shelf sediment

             patterns suggest the area of influence is also approximately

             ï¿½5,000 ft.



                  (4) The area of inlet influence is not masked by winter

             storm conditions although the elevated wave climate did

             coarsen the distal updrift shoreface. A fining of the distal











             44

             downdrift inner shelf was also noted and may be genetically

             related to the shoreface coarsening.



                   (4) It should be noted that the estimates of inlet ef f ect

             presented herein are based upon the surf icial sediment grain-

             size distribution patterns. Therefore, these estimates can

             only be used to delineate the limits of hydrodynamic

             inf luence. The data presented herein can not be used to infer

             how this hydrodynamic activity has effected the local sediment

             budget and therefore coastal accretion or recession rates.











                                                                           45


                                        REFERENCES


             Aubrey, D.G., 1979. Seasonal pattern of on/offshore sediment
                  movement. J. Geophys. Res., 84:6347-6354.

             Bein, A. and Sass E., 1978. Analysis of log probability plots
                  of recent Atlantic sediments-analogy with simulated
                  mixtures and implications to mode of transport.
                  Sedimentology, 25:57.5-581.

             Bowen, A.J., 1980. Simple models of nearshore sedimentation;
                  bea'ch profiles and longshore bars. In: The Coastline of
                  Canada, S.B. McCann (ed.), Geologic Survey of Canada, pg.
                  1-11.

             Bruun, P., Battjes, J.A., Chiu, T.Y., and Purpura, J.A.,1966.
                  Coastal engineering model studies of three Florida
                  coastal inlets (Sebastian, Hillboro, and South Lake
                  Worth): Coastal Engineering Laboratory, University of
                  Florida, (66/006).

             Carter, R.W.G. , 1988. Coastal Environments. Academic Press,
                  London, 617 pp.

             Chauhan, O.S., Verma, V.K., Prasad, C., 1988. Variations in
                  mean grain size as indicators of beach sediment movement
                  at Puri and Konark Beaches, Orissa, India. Jour. Coastal
                  Research, 4:27-35.

             Cherry, J., 1965. Sand movement along a portion of the
                  northern California coast. Tech. Memo. No. 14, U.S. Army
                  Corps of Engineers, Coastal Engineering Research Center,
                  Washington, DC, 125 pp.

             Civil, M.T., 1990, Holocene evolution of the inner continental
                  shelf, Ft. Pierce, Florida: (unpubl. M.S. thesis]:
                  Florida Institute of Technology, 136 pp.

             Coastal Technology Corporation, 1988. Sebastian Inlet District
                  Comprehensive Management Plan. Vero Beach, Fl. 53 pp.

             Coastal and Oceanographic Engineering Laboratory, University
                  of Florida, 1970. Tracing of coastal sediments movement
                  at Cape Canaveral, (70/012).

                       1987. Historical Florida offshore bathymetry's: an
                  atlas, Brevard County, pg. 1925-1965.











            46

            Clark, R.R., 1989. Beach conditions in Florida: a statewide
                  inventory and identification of the beach erosion problem
                  areas in Florida. Florida Department of Natural
                  Resources, Beaches and Shores Technical and Design
                  Memorandum 89-1, 43 pp.

            Davis, J.C., 1973.   Statistics and Data Analysis in Geology.
                  John Wiley & Sons, Inc., 550 pp.

            Davis, R.A., 1978. Sedimentology of Mustang and Padre Islands,
                  Texas; a time-series approach. J. Geol., 86:35-46.

                  , 1985. Beach and nearshore zone. In Coastal Sedimentary
                  Environments, Davis, R. A. (ed.), 2nd. ed., Spring-
                  Verlag, New York, 716 pp.

            Davis, R.A., and Ethington, R.L., 1976. Beach and Nearshore
                  Sedimentation. Soc. Econ. Paleont. Mineral. Spec. Publ.
                  24, 187 pp.

            Davis, R.A., and Fox, W.T., 1981. Interaction of beach and
                  tide generated processes in a microtidal inlet. Mar.
                  Geol., 40:49-68.

            Dally, W.R., Dean, R.G., and Dalrymple, R.A., 1985. Wave
                  height variation across beaches of arbitrary profile. J.
                  Geophys. Res., 90:11917-11927.

            Dean, R.G., 1983. Shoreline erosion due to extreme storms and
                  sea level rise. Univ. of Florida, Coastal and
                  Oceanographic Eng. Dept., UF/COEL-83/007.

            Dean, R.G.,   1988. Sediment interaction at modified coastal
                  inlets: processes and policies. In: Lecture Notes on
                  Coastal and Estuarine Studies, Vol. 29, D.G. Aubrey, L.
                  Weishar (eds.), Springer-Verlag, New York, Inc., pg. 412-
                  439.

            Dean, R.G.    and Walton, T.L., 1973. Sediment transport
                  processes in the vicinity of inlets with special
                  reference   to   sand  trapping.    Proceedings,    Second
                  International Estuarine Research Conference, Myrtle
                  Beach, pg. 1187-1200.

            Emery, K.O., 1960. The sea off southern California. Wiley &
                  Sons, New York, 366 pp.

            Ferland, M.A. and Weishar, L.L., 1984. Interprative analysis
                  of surficial sediments as an aid in transport studies of
                  dredged materials, Cape Canaveral, Florida: United States
                  Army Corps of Engineers, Coastal Engineering Research
                  Center, Miscellaneous Paper, CERC-84-3.











                                                                               47

              Friedman, G.M., 1967. Dynamic processes and statistical
                   parameters compared for size frequency distribution of
                   beach and river sand. Jour. Sed. Petrol., 37:327-354.

              Field, M.E. and Duane, D.B., 1974. Geomorphology and sediments
                   of the inner continental shelf, Cape Canaveral, Florida:
                   United States Army Corps of Engineers,                 Coastal
                   Engineering Research Center, Tech. Memo. #42.

              Folk, R.L. and Ward, W.C., 1957. Brazos River bar: a study in
                   the significance of    grain size parameters. Jour. Sed.
                   Petrology, 27:3-26.

              Foster, E.M. and Savage,     R.J., 1989. Methods of historical
                   shoreline analysis. Proc. Coastal Zone '89, Sixth
                   Symposium on Coastal and Ocean Management, Charleston,
                   S.C., 5:4420-4433.

              Fox, W.T. and Davis, R.A. 1976. Weather patterns and coastal
                   processes. In: Beach and Nearshore Sedimentation, Davis,
                   R.A. and Ethington, R.L., (eds.), SEPM Spec. Publ. #24,
                   pg. 1-23.

              Friedman, G.M. and Sanders, J.E., 1978. Principles of
                   Sedimentology. John Wiley & Sons, New York, 792 pp.

              Gibbs, R.J., 1974. A settling tube system for sand-size
                   analysis. Jour. Sed. Pet., 44:583-588.

              Gibbs, R.J., Mathews, M.D. and Link, D.A., 1971. The
                   relationship between sphere size and settling velocity.
                   Jour. Sed. Pet., 41:7-18.

              Giles, R.T. and Pilkey, O.H., 1965. Atlantic beach and dune
                   sediments of the southern United States. Jour. Sed. Pet.,
                   35:900-910.

              Gorsline, D.S., 1963. Bottom sediments of the Atlantic Shelf
                   and slope off the southern United States. Jour. Geol.,
                   71:422-440.              1

              Greenwood,    B.,   and   Davis,    R.A.,   Jr.   (eds.),     1984.
                   Hydrodynamics and sedimentation in wave-dominated coastal
                   environments. Mar. Geol., v. 60.

              Hayes, M.O., 1975. Morphology and sand accumulations in
                   estuaries. In: Cronin, L.E. (ed. ), Estuarine Research, v.
                   2, Academic Press, New York, pg. 3-22.

              Hoskin, C.M. and Nelson, R.V., 1971. Size modes in biogeni@c
                   carbonate sediment, southeastern Alaska, Jour. Sed. Pet.,
                   41:1026-1037.











             48

             Hubbard, D.K., 1975. Morphology and hydrodynamics of the
                  Merrimack River ebb-tidal delta. In: Cronin, L.E. (ed.),
                  Estuarine Research, v. 2, Academic Press, New York, pg.
                  253-266.

             Judge, C.W., 1970.. Heavy minerals in beach and stream
                  sediments as indicators of shore processes between
                  Monterey and Los Angeles, California. U.S. Army Corps of
                  Engineers,    Coastal    Engineering    Research     Center,
                  Washington, DC. Tech. Memo. #33, 44 pp.

             Jones, C.P. and Mehta, A.J., 1980. inlet sand bypassing
                  systems in Florida. Shore and Beach, 48:25-34.

             Komar, P.D., 1976. Beach Processes and Sedimentation.
                  Prentice-Hall, Englewood Cliffs, N.J., 429 pp.

             Komar, P.D. and Cui, B., 1984. The analysis of grain-size
                  measurements by sieving and settling-tube techniques.
                  Jour. Sed. Pet., 54:603-614.

             Krumbein, W.C. and Sloss, L.L., 1951. Stratigraphy and
                  Sedimentation. W.H. Freeman and Company, San Francisco,
                  Ca., 660 pp.

             Leatherman, S.P., 1979. Barrier Islands, from the Gulf of
                  St.Lawrence to the Gulf of Mexico. Academic Press, New
                  York, 325 pp.

             Lenard, J.E. and Cameron, B.W., 1981. origin of high-latitude
                  carbonate beach: Mt. Desert Island, Maine. Northwestern
                  Geol., 3:178-183.

             Liu, J.T. and Zarillo, G.A., 1989. Distribution of grain sizes
                  across a transgressive shoreface. Mar. Geol., 87:121-136.

             Meisburger, E.P. and Duane, D.B., 1971. Geomorphology and
                  sediments of the inner continental shelf, Palm Beach to
                  Cape Kennedy, Florida: U.S. Army Corps of Engineers,
                  Coastal Engineering Research Center, Tech. Memo. #54.

             Mehta, A.J., Adams, W.D. and Jones, C.P., 1976. Sebastian
                  Inlet: Glossary of Inlets Report Number 3: Florida Sea
                  Grant Report #14, pg. 5-15.

             Miller, R.L. and Zeigler, J.M., 1964. A study of sediment
                  distribution in the zone of shoaling waves over
                  complicated bottom topography. In: Papers in Marine
                  Geology, Shepard Commemorative Volume. Macmillan, New
                  York, pg. 133-153.











                                                                             49

             Milliman, J.D., 1972. Atlantic continental shelf and slope      of
                   the United States-Petrology of the sand fraction          of
                   sediments, Northern New Jersey to Southern Florida.
                   Geological Survey Professional Paper 529-J, 40 pp.

             Niedoroda, A.W. and Swift, D.J.P., 1981. Maintenance of the
                   shoreface by wave orbital currents and near bottom flow:
                   observations from the Long Island coast. Geophys. Res.
                   Lett., 8:337-340.

             Parkinson R.W., 1990. Summary report of Sebastian Inlet ebb
                   shoal core borings. Florida Institute of Technology,
                   Melbourne, FL., 15 pp.

             Pettijohn, F.J., 1975. Sedimentary Rocks. Harper and Bros.,
                   New York, 526 pp.

             Reineck, H.E. and Singh, I.B., 1980. Depositional Sedimentary
                   Environments. Springer-Verlag, New York., 549 pp.

             Smith, G.L. and Zarillo, G.A., 1990. Calculating long-term
                   shoreline recession rates using aerial photographic and
                   beach profiling techniques. Jour. Coastal Research,
                   6:110-120.


             Stauble,, D.K.,, 1988. Inlet flood tidal delta development
                   through sediment transport processes, In: Hydrodynamics
                   and Sediment Dynamics of Tidal Inlets, Springer-Verlag,
                   New York, pg. 319-347.

             Stauble, D.K., Da Costa, S.L., Monroe, K.L., Bhogal, V.K. and
                   de Vassal, G., 1987. Sediment dynamics of a sand bypass
                   inlet: American Society of Civil Engineers, Proc. of
                   Coastal Sediments '87, pg. 1624-1639.

             Stubblefield, W.L., Permenter, R.W. and Swift, D.J.P., 1977.
                   Time and space variation in surficial sediments of New
                   Jersey shelf. Jour. Sed. Pet., v. 45:337-358.

             Swift, D.J.P., Sanford, R.B., Dill, C.E. and Avignone, N.F.,
                   1971. Textural differentiation of the Bhoreface during
                   erosional retreat of an unconsolidated coast, Cape Henery
                   to   Cape   Hatteras,    Western    N.   Atlantic     shelf.
                   Sedimentology, 16:221-250.

             Taney, N.E., 1961. Littoral material of south shore of Long
                   Island, New York. U.S. Army Corps of Engineers Beach
                   Erosion Board, Washington DC., Tech. Memo. #128, 50 pp.

             Tsien, H.S., 1986. Differential transport of sand on the south
                   shore of Long Island. [unpubl. M.S. thesis]: State
                   University of New York at Stony Brook, 101 pp.











             50

             Visher, G.S., 1969. Grain-size distribution and deposition
                  processes. Jour. Sed. Pet., 39:1074-1106.

             Walther, M.P. and Douglas, B.D., 1991. Sorting characteristics
                  of tidal inlets. Proc. Coastal Sediments 91', pg. 1-3.

             Wang, H., Lin, L.,   Zhong, H. and Miao, G., 1991. Sebastian
                  Inlet Physical Model Studies, Part 1. Coastal Engineering
                  Laboratory, Univ. of Florida (91/001), 70 pp.

             Wang, H. , Lin, L. and Miao, G., 1992. Sebastian Inlet Physical
                  Model Studies, Final Report. Coastal Engineering
                  Laboratory, Univ. of Florida (92/006), 60 pp.

             Work, P.D., and Dean, R.G., in press, Even odd analysis of
                  shoreline change: Coastal Zone 191, 15 pp.

             Zenkovich, V.P., 1967. Process of Coastal Development.
                  Interscience Publisher, New York, 738 pp.





                                                                                                                           NOAA COASTAL SERVICES CTR LIBRARY


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