bluuebunny/crossref_metadata_2025 huggingface dataset:
ANALYSIS OF. TIDAL RECORDS OF THE 1964 ALASKAN TSUNAMI
Authors: Wilson Basil W.
Published: June 2019

The 8. 5 magnitude Alaskan earthquake of March 27, 1964,generated a great tsunami in the Pacific Ocean. This paper presents results of energy spectrum analyses conducted on a sampling of 24 of the marigrams from some 105 tide-stations which recorded the waves. In the numerical digital procedure used, two important properties of the evolving energy spectra are invoked; the frequency resolution and statistical confidence. High confidence is obtainable only at the expense of poor resolution, and vice versa. Excessive resolution may give rise to physically unreal spectral peaks, just as excessive restrictions for confidence may cause blunting of the spectrum and possible loss of physically real spectral components. A trial-anderror compromise between these properties was sought by testing the effects on the energy spectra, for Hilo, Hawaii, of the parameters that control the digital process. An optimum selection of spectrum parameters was finally made so that the primary and secondary wave forms of components, identified by the analysis for the marigram of San Francisco, Calif., most closely agree with the corresponding wave forms obtained by use of Chrystal's (1904) graphical method of residvation analysis. Using the parameters so determined, and by application of band-pass filters in the digital analysis, the most prominent peaks of spectral energy in the marigrams of the 24 stations are isolated and their wave-forms computer-plot - ed. In all cases a recognizable long-period wave component is found having a frequency between 0.50 and 0.65 cy/hr (average period 1.73 hrs). General similarity of these primary wave forms as to period and shape of beats suggests their common origin at the source of the earthquake disturbance. The secondary wave forms of higher frequency (periods generally less than 40 mins) are ascribed to local free oscillations forced by the primary wave trains at the receiving stations. In some, but not all of the marigrams there is evidence of wave systems averaging 3.2 hrs in period. These are thought to be an independent wave-train originating at source.
WAVE RUN-UP CAUSED BY NATURAL STORM SURGE WAVES
Authors: Grune Joachim
Published: June 2019

This paper describes results of field measurements on wave run-up caused by storm surge waves. The measurements have been done with newly developed run-up probes at two locations at the German Bight with different dyke profiles. It was found from the results that the wave runup, measured under real sea state conditions, have greater values than predicted by commonly used formulae. Furthermore the wave climate and the breaker type seem to have an influence on the magnitudes of wave run-up.
WATER WAVES PROPAGATING ON BEACHES OF ARBITRARY SHAPE
Authors: Chen Y.Y. , Hwung H.H.
Published: June 2019

When a small amplitude wave climbing along an arbitrary sloping beach from deep water toward the shore, the variation of characteristics in the process of wave motion has been described in this paper. From the results of theoretical derivation, it is found out that the variation of water surface and amplitude are function of beach slope) and dimensionless distance (kx~) from the shore. And under the condition of the beach slope is a = 0 and a = °o that the solution will become a progressive wave and a standing wave respectively.
EXAMPLES OF STORM SURGE PREDICTION MODELS
Authors: Lencioni P. , Benque J.P. , Coeffe Y.
Published: June 2019

For a given site, deterministic models may be applied to predict the tide level with a rather good accuracy. However, a difference is observed between the observed and predicted tide level under storm condition. This difference is called storm surge. Two different storm surges prediction models are presented for the site of Le Havre ; an autoregressive model ; a model using wind and pressure local data. The autoregressive model can be used for a prediction 5 hours in advance. The availability of accurate wind and pressure predictions by the Meteorological Service of Le Havre within 36 hours in advance makes the use of the second model of great interest because it provides the possibility of predictions within 39 hours in advance.
APPLICATIONS OF A NUMERICAL SHALLOW WATER WAVES MODEL
Authors: Hauguel A. , Pechon Ph.
Published: June 2019

This paper relates three applications of a numerical model of storm waves in shallow waters developed in LNH. The equations are recalled at first and then the applications performed are presented. The numerical model has been used in the case of the port of Fecamp, on the English Channel coast, on which the results of a scale model were available. The computed results compare well with the scale model measurements. The second case is the s imulation of a t sumami induced by a submarine landslide which appeared in 1979 near Nice ; the mode 1 has permitted the simulation of the rising of the wave. The last applications consisted in simulating breaking waves by introducing a dispersion term in the equations. This simulation has been tested with a one-dimensional model at first. The results show that the numerical model reproduces the elevation of the mean sea surface due to the loss of energy in breakings. Then the longshore current induced by breaking waves coming obliquely over a rectilinear sloping shore has been reproduced with a two dimensional model. The results show that the model is able to compute with a good accuracy re fraction, diffraction and reflection, and that it appears to be very interesting for longshore currents simulation.
ON THE VARIATION OF CHARACTERISTICS OF TWO WAVE TRAINS CROSSING IN INTERMEDIATE DEPTH
Authors: Hwung H.H. , Tsai C.P.
Published: June 2019

In this paper , the authors paid attention to the non- linear interaction of two free wave trains crossing in intermediate water depth. From theoretical approaches , the velocity potential and water surface elevation have been expanded to the second-order by perturbation method. And wave height , velocity of fluid particles , pressure distribution , wave thrust and energy density of the common wave are also investigated. In order to verify the theoretical results , elaborated and numerous experiments have been performed. Some of the remarkable coincidence are obtained and the conclusions have been presented in this paper.
A SOUTH AFRICAN WAVE CLIMATE STUDY
Authors: Rossouw J. , Coetzee L.W. , Visser C.J.
Published: June 2019

A study was made, using all the available sources of deepsea wave data around the South African coast, to establish a statistical representation of the wave climate in this region. Data obtained from clinometer observations, the Datawell Waverider and voluntary observing ships were found to be the most useful. The most accurate source of height, period and spectral information came from the Waverider which has been in extensive use in the region since 1969. To optimise the information value of these data a sophisticated data qualification technique was developed for digitised Waverider data in order to exclude poor data. This technique was also found to be useful in optimising the operational efficiency of a Waverider station. A clear pattern was obtained for the general wave climate around the South African coast; this is in accordance with the pattern that may be expected from the weather climate affecting this region. Of interest are the SE'ly winds generating increased wave heights in proportion to the distance offshore from the west coast as well as the effect of the Agulhas current, opposing the SW'ly waves along the east coast, also creating high-wave conditions.
FIELD EXPERIMENTS ON LONGSHORE SAND TRANSPORT IN THE SURF ZONE
Authors: Kraus Nicholas C. , Isobe Masahiko , Igarashi Hajime , Sasaki Tamio O. , Horikawa Kiyoshi
Published: June 2019

Eight fluorescent sand tracer experiments were performed in energetic surf zones on natural beaches and on beaches near structures to measure the short-term longshore sand transport rate. Tracer of up to four distinct colors was injected on a line crossing the surf zone to investigate the on-offshore distributions of the longshore sand adveetion velocity and transport rate. The tracer advection velocity, v , and the depth of mixing into the bed, b, were determined from large numbers of cores taken in situ throughout the sampling area. The sand advection velocity and mixing depth were not constant across the surf zone, but usually exhibited a maximum either toward the shoreline or toward the breaker line, or in both regions. The local breaking wave height, H. , and horizontal current velocity in the surf zone (yielding an average longshore current velocity V) were also measured. The data were interpreted with simple dimensional arguments to give the following results: b = 0.027 H,, v = 0.011 V, and the volumetric transport rate Q = 0.024 H V. Agreement was also found between the measured total longshore sand transport rate and a predictive expression due to Bagnold involving the breaking wave power and average longshore current velocity. Although the results appear reasonable and consistent, a problem remains concerning the apparent decrease in tracer advection speed alongshore recorded in most experiments at the longer sampling times.
BARRIER BEACH FEATURES OF CALIFORNIA
Authors: Converse Hugh
Published: June 2019

Remarkable near-continuous examples of barrier beach features are found in many coastal areas, worldwide. The most notable North American examples are the margins of North America along the Atlantic and Gulf of Mexico, where barrier islands are found along more than 60 percent of the coastline. There are, in fact, 280 large-scale individual barrier features, 70 of which are highly developed and 100 more are being developed (Hobson, et al, 1980). These barriers have been built out of the enormous volumes of sediment available from the extensive watersheds of eastern and central North America and, through the ages, appear to have migrated long distances across a wide continental shelf in response to the interplay of waves and tidal currents, eustatic sea level fluctuations and sand supply. Barrier features are less in evidence on the west coast of North America though they are by no means absent. For example, along a 60-mile reach of the Oregon-Washington coast adjacent to the Columbia River mouth, impressive barrier spits have straightened the coast by blocking the bays and headlands. These are black-sand beaches, formed from the large sediment supply of the extensive inland basin of the Columbia (Bascom, 1980; Cooper, 1967), which has the 29thlargest discharge of the world's rivers (Inman and Nordstrom, 1971). The longest spit in this reach is about 19 miles long. The North Pacific coast is a high-energy wave environment, and these spits are continually shifting. Indeed, one of the most outstanding examples of continuing shore movement in North America is found at Cape Shoalwater at the north side of Willapa Bay, Washington where the inlet has migrated about 2.5 miles northward in the last 95 years across homesites, a cemetery and a lighthouse (Terich and Schwartz, 1981; US Corps of Engineers, 1971a).
SHORE PROTECTION AT VENICE: A CASE STUDY
Authors: Muraca A.
Published: June 2019

The lagoon of Venice (N. Adriatic) is the most important in Italy (Fig. 1). Between 1840 and 1933 the tifial entrances facing the lagoon were controlled by six large jetties, after the construction of which more evident erosion phenomena appeared in some tourist resort beaches near the inlets. Detailed historical, movable bed models, and field studies have recently been conducted with the aim of defining a proper defence system for these beaches. The results of these studies are reported here.
SEDIMENT BYPASSING AT MIXED ENERGY TIDAL INLETS
Authors: FitzGerald Duncan M.
Published: June 2019

Inlet sediment bypassing, through the previously recognized mechanisms of stable inlet processes and ebb-tidal delta breaching, has been documented at six mixed energy (tide-dominated) coasts around the world including the coasts of: central South Carolina, Virginia, southern New Jersey, New England, the East Friesian Islands, and the Copper River Delta in Alaska. Regardless of the mechanism, the end product of the bypassing process is the formation of a large bar complex that migrates onshore and attaches to the downdrift inlet shoreline. Thus sediment bypassing is a discontinuous process at mixed energy tidal inlets. The morphology of the bar complexes is highly variable with widths ranging from 40-300m and lengths from 300 to over 1500m. Generally, the size of the bar complexes increases as inlet size increases and as the rate of longshore sediment transport increases. The frequency of bar welding events at mixed energy inlets varies from 3-7 years. The location where the bars attach to the downdrift beach and length of shoreline that is affected by the bar welding process is dependent on inlet size, orientation of the main ebb channel and wave versus tide dominance of the shoreline.
SYNTHESIS OP HURRICANE RESPONSE HYDROGRAPHS
Authors: Sobey Rodney J.
Published: June 2019

A hindcasting methodology is described for the total water level and wave hydrographs at a coastal site during a hurricane. It accommodates phasing of the separate components of the sustained water level (astronomical tide, storm tide, breaking wave setup) , as well as storm variability and coastal bathymetry. Complete hindcast models are utilised, but an intermediate cost and precision is achieved by compromising the number of complete hindcast storms, rather than the precision of the hindcast model. A synthesis technique is developed to predict the response hydrographs of the remaining storms in the historical data set.
MODELING COASTAL CURRENTS AND SEDIMENT TRANSPORT
Authors: Sheng Y. Peter , Butler H. Lee
Published: June 2019

An efficient three-dimensional model of coastal currents and sediment transport has been developed. Simulations of tide- and wind-driven currents and sediment transport in the Mississippi Sound are presented. Results of a laboratory study on settling, resuspension, and deposition of sediment are briefly described. Wave effect on sediment resuspension is also addressed.
CHANNEL SHOALING PREDICTION: A METHOD AND APPLICATION
Authors: Harley R.B. , Dean R.G.
Published: June 2019

Due to concerns of possible shoaling problems, an extensive field survey program was carried out at the site of the proposed Cerrejon coal port on the Caribbean coast of northeast Colombia. The program yielded considerable data on winds, waves, currents, and sediment factors. Techniques for the primary measurement of sedimentation-related tendency included dredged test pits, scour crosses, and suspended sediment samplers. The port plan includes dredging a 4.6 kilometer long channel varying from 12 to 21 meters in depth. In order to assess the magnitude of maintenance dredging and related problems, a method was developed for incorporating the sediment response measurements into predictions of the areal and seasonal distributions of bed load and suspended sediment deposition. Offshore test pits were monitored for rate of filling and character of the material being deposited. Suspended sediment samplers were similarly observed and also provided data on concentration versus depth. The procedure which was developed for analysis and interpretation of the data included extrapolation of suspended sediment data to the seabed, investigation of correlations between wind activity and deposition rates, application of test pit data to a channel of larger dimensions, and testing of hypotheses regarding transport mechanisms. The procedure concluded that average annual shoaling would be approximately 300,000 m and predicted areal and seasonal variation of deposition rates.
CONSTRUCTION OF A BREACH CLOSURE IN A BARRIER ISLAND
Authors: McCarthy M.J. , Schmeltz E.J. , Lehan G.R.
Published: June 2019

A breach was opened in the barrier beach along the south shore of Long Island, New York during a winter storm in January, 1980. Due to public safety and environmental concerns, a contract to close the breach using sand fill was awarded to a local contractor. This paper discusses the evolution of the construction procedures developed to allow the contractor to successfully complete the project on schedule and on budget.
SPENDING BEACH BREAKWATER AT SALDANHA BAY
Authors: Zwemmer D. , Van 't Hoff J.
Published: June 2019

This paper describes the design and construction of a sand breakwater at Saldanha Bay exposed to the severe swell conditions of the south Atlantic. The design of this spending beach breakwater was aimed to establish a seaward profile with sufficient "playroom" to incorporate profiles resulting from extreme wave conditions. As far as the construction is concerned the emphasis is put on the sandlosses during execution of the works. Finally the designed profile is compared with the actual established beach profile.
SAND MOVEMENT INTO CARMEL SUBMARINE CANYON, CALIFORNIA
Authors: Dingler J.R. , Anima R.J.
Published: June 2019

Carmel Submarine Canyon heads in shallow water near Monastery Beach at the southeast corner of Carmel Bay, California, U.S.A. Very coarse sand, shaped into large oscillation ripples, covers the narrow shelf between the beach and the canyon; when this sand enters the canyon head, it lies at angles as great as the angle of repose. In some areas, these sand slopes show evidence of active grain flows in the form of downslope-coarsening, inversely graded deposits. The results of a dyed-sand tracer study adjacent to the canyon show that sand moved canyonward during the summer of 1979. Initially the dyed sand, which had been shaped into an oscillation ripple in the center of a 20-m by 60-m grid, moved offshore en ma sse. After a few days, though, the dyed sand dispersed with the center of mass moving canyonward. As wave-transported sand accumulates along the canyon rim, the upper slopes oversteepen, thereby causing some of the sand to avalanche downslope. Systematic changes in sand levels along three lines of rods over 15 months document preferential deposition of sand along the upper slopes; the greatest change occurred at the top of the lines (12-15 m depth) and the least at the bottom (30-40 m). Greater accretion during the spring months than during the summer months probably reflects the more energetic springtime wave climate. Between October 1981 and October 1982, 5.7 m3 of sand was deposited per meter alongslope on the middle line, which gives a calculated depositional rate of approximately 5 00 m /yr in the study area. Although we have monitored this area for over a year, we have not yet documented any large-scale events capable of flushing sand out of the canyon head. The only erosive event we have observed was a small grain flow we generated while digging on the slope.
MODEL TESTS ON LITTORAL SAND TRANSPORT RATE
Authors: Kamphuis J.W. , Sayao O.F.S.J.
Published: June 2019

This paper is an analysis of two sets of experimental results on littoral sand transport. A littoral sand transport expression is proposed, relating littoral transport rate to surf similarity parameter and hence to wave energy dissipation rate. The expression indicates that the "constant' in the CERC formula is dependent on the mobile bed beach slope and on the breaker index. The expression is also compared with some of the few published field measurements.
THE RATE OF LONGSHORE SEDIMENT TRANSPORT AND BEACH EROSION CONTROL
Authors: Tsuchiya Yoshito
Published: June 2019

The main purpose of this paper is to propose an ideal methodology for beach erosion control from the viewpoint of controlling the total rate of longshore sediment transport. For this, a new formulation of the rate of longshore sediment transport is made. The total rate is directly proportional to the longshore component of wave power in field coasts, but not in laboratory ones. How to control the total rate of longshore sediment transport is considered. There are two ways applicable for practical purposes. The first is to decrease the breaker depth by changing the bottom topography, and the second to decrease the incident angle of breaking waves by changing either the bottom topography or the inclination of shoreline to the incidence of predominant waves. Two typical, but ideal examples are explained for beach erosion control by this methodology.
SEDIMENT TRANSPORT UNDER SHEET FLOW CONDITION
Authors: Horikawa Kiyoshi , Watanabe Akira , Katori Sadakazu
Published: June 2019

A series of laboratory experiments in an oscillatory tank was carried out to investigate the sheet flow of sediment. Objectives of the study were to determine the criterion for inception of sheet flow, and to evaluate the sediment transport rate under the sheet flow condition. In order to proceed with the investigation, it was necessary to develop devices appropriate for tracing the sediment particle movement, and for measuring the extremely dense sediment concentration in the moving layer of sheet flow. The chief results are: 1) the criteria for the inception of sheet flow given by Manohar C1955) and by Komar and Miller (1974) are both applicable to materials composed of spheroidal particles, and 2) the average rate of sediment transport for sheet flow is well described by an empirical relationship given by Madsen and Grant (1976) for the bed load transport rate on a plane bed in oscillatory flow.
MEASURED AND COMPUTED COASTAL OCEAN BEDLOAD TRANSPORT
Authors: Niedoroda Alan William , Ma Chen-Mean , Mangarella Peter A. , Cross Ralph H. , Huntsman Scott R. , Treadwell Donald D.
Published: June 2019

A comparison is made between the measured infilling of two test pits off the coastline of San Francisco and predictions using a coastal bedload transport model. The model, based on the work of Madsen and Grant (1967), relates the bedload transport to the bottom shear stress through an empirical relationship based on laboratory experiments. The bottom shear stress is estimated from the bottom currents created by waves and low frequency currents. The model applies beyond the breaker zone in contrast to littoral transport. The test pits, dredged as part of the Southwest Ocean Outfall Project for San Francisco, were located 1.6 km (1 mi) and 3.2 km (2 mi) offshore in 13' m (42 ft) and 16 m (53 ft) of water. The depth of the pits relative to the natural seabed was about 8.4 m (25 ft). The comparison was conducted for a period up to 2 months in the fall of 1978. The paper discussed the quality and scope of available data required as input to the model and shows how regional wave data were trans formed to augment local measurements. Uncertainties in model results stemming from limitations in the input data are presented. With suitable adjustment of the scale of the gravitational term in the expression for the Shields parameter, overall agreement between computed and measured bedload was accomplished within the limits of accuracy of the bathymetric surveys. A sensitivity analysis of selected input conditions and coefficients was also conducted.
HEIGHT DISTRIBUTION OF ESTUARINE WAVES
Authors: Barthel V.
Published: June 2019

A field investigation program on waves was carried out in the Weser estuary, German Bight of the North Sea. Wave height and period distributions in this complicated wave climate can be approximated by a Rayleigh distribution. Empirical distributions of the wave heights characterise the different regions of the estuary. The presence of wave grouping as well as the group bounded long waves are shown in a few examples. The necessity of further investigations and analysis is highlighted.
RESUSPENSION OF DEPOSITED COHESIVE SEDIMENT BEDS
Authors: Mehta Ashish J. , Partheniades Emmanuel
Published: June 2019

Surfieial layers of estuarial fine, cohesive sediment beds are deposited from flow and often are in a state of partial consolidation. A series of laboratory investigations were carried out to elucidate the erosional behavior of deposited cohesive sediment beds in flumes using kaolinite. A significant feature of such beds is that they are stratified with respect to the density and the cohesive shear stength. Under a given bed shear stress, erosion occurs at a continuously decreasing rate up to a depth at which the bed shear stress equals the shear strength. This bed shear stress is therefore also equal to the critical shear stress for erosion at that depth. An expression for the rate of erosion relating this rate to the difference between the bed shear stress and the critical shear stress has been obtained. The critical shear stress increases both with depth and with the bed consolidation time. The rate of erosion decreases with increasing consolidation time.
BED LOAD TRANSPORT OF FINE SAND BY LAMINAR AND TURBULENT FLOW
Authors: Grass Anthony J. , Ayoub Ragaei N.M.
Published: June 2019

An experimental study is described in which the rate of transport of fine sand over a flat bed was measured as a function of the shear stress exerted on the bed by both laminar and turbulent flows, for a range of water temperatures. The results confirm the great sensitivity of the transport rate to changes in both shear stress and temperature over the test range. The hypothesis is propounded that in certain specified circumstances, the net rate of local bed load transport generated by an arbitrary unsteady flow, can be estimated by integration, using the measured steady laminar flow transport relationships in conjunction with the time history or probability distribution of the fluctuating bed shear stress. The concept has been tested using the measured data with encouraging results. It is suggested that this method of linking the characteristics of the near bed flow field to the local induced rates of sediment transport could be productively applied in a range of studies including the initiation and development of bed sand ripples by the action of various combinations of waves and steady currents.
SURVEY TECHNIQUES/PROCEDURES AND DATA PROCESSING FOR MONITORING NEARSHORE SEDIMENT TRANSPORT
Authors: Zacks J.
Published: June 2019

The cost of many coastal projects is often increased by the expensive beach repair and maintenance required to remedy the destabilising effects of structures on the adjoining coastline. Physical and/or mathematical models have been developed for use in planning these projects in order to predict and quantify the effects of marine sediment transport on the coastal topography. Such models need to be calibrated against prototype data and one method of gauging volumetric sediment movement is by successive bathymetric/ topographic profiting surveys which are performed seasonally and annually. Since large quantities of sediment are related to small changes in bed elevation it is clear that this profiling needs to be done with the utmost precision* The areas most affected extend from the beach through the surf zone to water depths of about 25 metres. The surf zone in particular is a dynamic and hostile area which falls outside the traditional activities of both the hydrographic and land surveyors. Consequently innovative methods, deficient in sound survey principle and practice, have often been pursued in this area without any attempt being made to assess the tolerance on the data. This paper attempts to show that it is possible to produce reliable and verifiable results to the required accuracy by using conventional survey equipment and techniques, also by taking the necessary precautions against the many possible sources of survey error. The procedures and techniques described have evolved from NRIO's involvement over the past decade in major projects at Richards Bay, Durban, Koeberg and in False Bay. The results of a recent verification investigation are fully reported in this paper.
NEW FRAMEWORK FOR PREDICTION OF LONGSHORE CURRENTS
Authors: Fleming C.A. , Swart D.H.
Published: June 2019

The accuracy of prediction of longshore sediment transport depends largely on the accuracy with which the wave-driven longshore currents within the breaker zone can be predicted. Longuet-Higgins (1970) developed a formulation for longshore transport which is widely used today. In the present paper the basic theory of Longuet-Higgins is reexamined. The effect of bed roughness on the magnitude of the longshore current is quantified with the aid of over 350 individual data sets and the theory is theoretically extended to include the effect of random waves, in a similar way to Battjes (1974), and higher-order waves. For this latter purpose the Vocoidal water wave theory of Swart (1978) is used. It is shown that the use of Vocoidal theory leads to a velocity distribution which is in closer correspondence to measured data than that predicted by using linear wave theory.
THE EXPERIMENTAL VERIFICATION OF NUMERICAL MODELS OF PLUNGING BREAKERS
Authors: Kjeldsen Soren Peter
Published: June 2019

Results of a WAVE-FOLLOWER EXPERIMENT are presented, in which a moving current meter entrained in the crest of a steep Stokes wave and a moving high-speed film camera follows the wave with its non-linear phase velocity. Measurements of wave particle velocities are then obtained both in non-breaking steep wave crests, and in breaking waves. The breaking waves in deep water conditions are obtained by the application of a non-linear sweep frequency modulation technique, and the Stokes wave becomes unstable due to interaction of 13 wave components focused into one single point in space and time, KJELDSEN 1982. The result of this interaction is a large freak wave, breaking as a plunging breaker in deep water. Measured crest particle velocities obtained with the current meter exceeded the phase velocity of this wave with 36 %. Digitalisation of the high-speed film showed that particle velocities at the very tip of the plunging jet obtained the value 2.65 times the linear phase velocity. These results are then compared with predictions obtained from numerical simulations by LONGUET-HIGGINS & COKELET 1976 and VINJE & BREVIG 1980.
LONGSHORE SEDIMENT TRANSPORT ON DEAN BEACH PROFILES
Authors: McDougal William G. , Hudspeth Robert T.
Published: June 2019

Natural beaches exhibit an equilibrium profile that is planar nearshore and non-planar, concave-up offshore. The longshore current on these Dean equilibrium beaches is shown to depend on the location of the intersection between the planar and non-planar profiles and on the dimensionless mixing strength parameter if the eddy viscosity coefficient is linearly dependent on the distance offshore. The effect of the profile intersection on the longshore sediment transport rate is demonstrated for two energetics based sediment transport models; viz. the Bagnold and energetics stress models.
BEACH RESPONSE TO COASTAL WORKS GOLD COAST, AUSTRALIA
Authors: Macdonald H.V. , Patterson D.C.
Published: June 2019

The paper outlines the results of comprehensive beach surveys carried out over more than 20 years showing the effects of seawalls, groynes and beach nourishment on the beaches of the beach resort city of Gold Coast, Australia. Beach profile changes and, in particular, quantification of the overall extent of accretion and erosion resulting from groynes which interrupt the longshore movement of sand are outlined. The paper confirms the already known principles of behaviour of these coastal works and documents clearly the full detrimental impact that inappropriate structures can have on a natural sand beach system.
A NEW OSCILLATORY FLOW TUNNEL FOR USE IN SEDIMENT TRANSPORT EXPERIMENTS
Authors: King David B. , Powell John D. , Seymour Richard J.
Published: June 2019

The details of a new oscillatory flow tunnel at Scripps Institution of Oceanography are discussed. The flow tunnel has a large crosssection and large water excursion distance. The piston motion is programmable. The test bed can be tilted. These, and other aspects, make the facility useful to a wide variety of oscillatory flow sediment transport experiments.
BEACH RESPONSE TO LONG PERIOD LAKE-LEVEL VARIATION
Authors: Wood William L. , Weishar Lee L.
Published: June 2019

A 4-year set of beach and offshore profiles, measured at monthly intervals, is evaluated to determine the effect of wind-wave forcing and long period (1 year or greater) lake-level variation on beach profile change in the "tideless" Great Lakes. This evaluation indicates two distinct regions of change in the beach and nearshore area of these profiles. The beach-berm region responds directly to lake-level modulation of wind-wave forcing. This response occurs on two time scales (seasonal and long period), but always in direct relation to mean lake-level variation. The inner-bar actively changes under the influence of wind-waves, but appears to lack a well-defined seasonal pattern. Empirical eigenfunction analysis is applied to these data in order to statistically quantify the significance of these observed changes. This analysis provides confirmation of a hypothesized long-period (years) variation of the beach and berm in direct response to lake-level variation.
ESTIMATING ERROR OF COASTAL STAGE FREQUENCY CURVES
Authors: Prater Mark D. , Hardy Thomas A. , Butler H. Lee , Borgman Leon E.
Published: June 2019

A computer intensive statistical procedure known as the bootstrap has been used to estimate the error in coastal stage-frequency relationships due to uncertainties in hurricane meteorological distributions. These stage-frequency relationships are developed through the use of a joint probability method, so that the probability of a storm event is the product of the probabilities of the individual independent components which comprise that storm event. The bootstrap technique provides an estimate of the error of the stage-frequency by determining the variation possible in each component's probability distribution. This variability is due to the construction of the distribution from a finite set of historical events. An example of the bootstrap is given and stage frequency results and error estimates typical of a coastal region are shown.
REDESIGN OF ENTRANCE STRUCTURES FOR TWO SMALL CRAFT HARBORS IN OHIO
Authors: Edge Billy L. , Sill Ben L. , Swartzmiller James A. , Fisher John S.
Published: June 2019

Wildwood Harbor and Chagrin River are two areas on Lake Erie at which intensive boating activities occur throughout the recreational months of April through October. At Wildwood Harbor (Figure 1) an enclosed basin exists with a relatively open mouth which allows excessive wave activity to enter. These waves often focus directly on the launch ramp opposite the entrance. At Chagrin River [Figure 2) a major project was recently completed to stabilize the river entrance which had experienced substantial shoaling, and to help prevent winter ice blockage. The jetties and associated spending beach in the River worked well to prevent continuous shoaling and allow the river to flood and carry the ice lakeward; however, significant reflected waves resulted from this construction affecting navigation through the entrance and boats in the adjacent Yacht Basin.
THE COMPUTATION OF BED SHEAR IN A NUMERICAL MODEL
Authors: Leeuwenstein W. , Wind H.G.
Published: June 2019

Obstructions located in coastal and offshore waters usually disturb the natural flow pattern. This disturbed flow will, in general, cause local morphological changes in the position of the erodable boundary. Often these changes should not be allowed to exceed certain limits, for example, when local scour around an offshore construction may endanger foundations. Local morphological changes result from changes in the local sediment balance, brought about by the flow disturbance. In the present paper a mathematical model is described which gives the bottom shear stresses and the configuration of the seabed around an obstruction using a computation of the two dimensional turbulent flow field. The obstruction considered is a submarine pipeline laid uncovered on a seabed consisting of non-cohesive sediment. A research project on the local scour near submarine pipelines is being carried out at the Delft University of Technology. Part of the project is the application and extension of an advanced numerical flow model for scour development near pipelines on the seabed exposed to current action. This work is being carried out in cooperation with the Delft Hydraulics Laboratory. The code of the flow model has been developed in a joint venture between the Delft Hydraulics Laboratory and the Laboratoire National d"Hydraulique in France. The turbulent flow field is computed taking into account the influence of turbulence generated at the bed and by the pipe. The bed shear stresses are assumed to play the key role in the interaction between the flow and the seabed. In the computer model the bed shear is related to the flow through the "law of the wall". The model operation is schematized in the diagram below in which the first loop represents the evolution of the velocity field through a series of hydraulic time steps. After the velocity field is stabilized, in the second loop one morphological time step can be used for the computation of the local seabed changes. In this second loop the computed bed shear is applied together with a sediment transport formula. After the morphological time step a new bed topography is obtained and a new grid is generated for the next flow computation.
NORTH SEA TIDE AND STORM SURGE INVESTIGATION
Authors: Siefert Winfried
Published: June 2019

An extensive investigation of tide and storm surge measurements in the coastal waters of the southeastern North Sea (German Bight) is now being concluded, giving new hints to tidal behaviour in a complex area, consisting of extended tidal flats, interrupted by islands, sand banks, estuaries and gullies. The analysis was promoted by the "German Coastal Engineering Board" (KFKI) and will be the basis of further investigations of the storm surge conditions in tidal estuaries. Tidal records and high and low water values of 130 gauges in 2 an area of 12.000 km (5.000 sq.mi.) were used to evaluate cotidal lines in the German Bight mean tide curves regressions between different locations neap and spring tide conditions secular changes over the last 80 years storm surge development.
NUMERICAL SIMULATION OF STORM SURGES BY MULTI-LEVEL MODELS
Authors: Yamashita Takao , Tsuchiya Yoshito
Published: June 2019

The numerical simulation of storm surges in shallow bays is investigated by multi-level models such as the 2-level and FE-FD models which are used to consider the velocity profiles in wind-induced currents. These models were applied to hindcast the storm surge caused by Typhoon 7916 in Osaka Bay with the result that the water surface elevations and currents induced by the storm surge were successfully simulated.
SEDIMENT RESPONSES TO NATURAL WAVES
Authors: Nielsen Alexander F. , Gordon Angus D.
Published: June 2019

This paper is concerned with wave-induced seabed forcing functions and sediment responses on the Australian South East Continental Shelf. The transfer of surface displacement energy to near-bed oscillatory water movement energy is examined with respect to linear and second order wave theories. Seabed sediment responses are examined by comparing field bedform size data to laboratory data with a view to determining characteristic spectral parameters that may be applied with existing theories to predict sediment responses under natural wave spectra. A rippled bed incipient motion criterion incorporating the contribution to boundary shear stress made by the presence of bedforms as well as particle size is developed empirically from field data using dimensional analysis techniques.
FIELD INVESTIGATIONS IN THE TOW STUDY PROGRAMME FOR COASTAL SEDIMENT TRANSPORT IN THE NETHERLANDS
Authors: Derks H. , Stive M.J.F.
Published: June 2019

Field campaigns were conducted in 1981 and 1982/83 on the Dutch coast near Egmond. Measurements were made of surface elevations, water velocities and sediment concentrations in 3 to 8 surf zone locations and 2 to 5 offshore locations simultaneously. A total of 50 measurement series was obtained under a variety of weather conditions, resulting in offshore wave heights of 0.2 to 4.6 m. A description is given of the field set-up, the instruments and measurements, and the collected data. The quality of the various measurement systems and the data produced has been investigated extensively by intercomparison of instruments and devices in the field. The results are reported here.
FIELD OBSERVATION ON SUSPENDED-LOAD IN THE SURF ZONE
Authors: Katoh Kazumasa , Tanaka Norio , Irie Isao
Published: June 2019

Both the concentration of suspended-load and the

current velocity have been measured continuously in

the surf zone. In order to measure the concentration

of the suspended-load in the surf zone, a optical

densitometer has been developed. The current

velocity was measured by means of electromagnetic

current meters. According to data analyses, the

mean concentration of the suspended-load is high in

the final breaking zone and in the breaker zone. In

the final breaking zone, the concentration

fluctuates with the period of the incident waves.

On the other hand, it fluctuates with the period

longer than 40 seconds in the breaker zone and it

becomes high when the current is offshoreward. The

directions of the net transport of the suspendedload

in the middle layer in and near the surf zone

are offshoreward.
SURVEY TECHNIQUES USED TO MEASURE NEARSHORE PROFILES
Authors: Gable Christopher G. , Wanetick Jerome R.
Published: June 2019

The three most common survey techniques used to measure nearshore profiles are (1) conventional boat-sonic depth sounder; (2) hydrostatic pressure profiler; and (3) the self powered Coastal Research Amphibious Buggy (CRAB)- Theory of operation and methodology used for each technique are summarized and evaluated. Three separate field tests using survey data from each technique are evaluated for system repeatability. Data reduction, sea surface correction, and filtering methods for boat-depth sounder survey data are examined.
LONGSHORE VARIABILITY OF WAVE RUN-UP ON NATURAL BEACHES
Authors: Holman R.A. , Sallenger A.H.
Published: June 2019

The longshore variability of wave run-up from a natural beach is examined using data from a large field experiment at the Field Research Facility in Duck, North Carolina, in October, 1982. Two particular runs were selected for intensive analysis. These were chosen to represent a dissipative and a reflective surf zone condition, so have I ribarren numbers 0.97 and 1.81 respectively. The dissipative data run showed much more uniform statistics in the longshore than did the reflective run. Also, the dissipative run was dominated by the infragravity band energy while the reflective run was dominated by the incident band. Selection of several important frequency bands for frequency-domain EOF analysis showed that the lower frequency peaks appeared to be associated with leaky modes (very long longshore wavelengths) and the pier had little influence. On the other hand, higher frequencies were clearly influenced by the pier in both amplitude and phase. An interesting subharmonic peak from the reflective run appeared to be a low (but not zero) mode standing edge wave. A new technique,time exposure photography, is introduced. It allows the quick determination of longshore variability such as would be produced by a dominant standing edge wave. It can also be used to image offshore bathymetry and sand bar systems.
ON PREDICTING INFRAGRAVITY ENERGY IN THE SURF ZONE
Authors: Sallenger Asbury H. , Holman Robert A.
Published: June 2019

Flow data were obtained in the surf zone across a barred profile during a storm. RMS cross-shore velocities due to waves in the infragravity band (wave periods greater than 20 s) had maxima in excess of 0.5 m/s over the bar crest. For comparison to measured spectra, synthetic spectra of cross-shore flow were computed using measured nearshore profiles. The synthetic spectra were calculated assuming a white runup spectrum of mode-4 edge waves of unit amplitude, although the results would be essentially the same for standing waves or any edge-wave mode above 2. The structure, in the infragravity band, of these synthetic spectra corresponded reasonably well with the structure of the measured spectra. Total variances of measured cross-shore flow within the infragravity band were nondimensionalized by dividing by total infragravity variances of synthetic spectra. These nondimensional variances were independent of distance offshore and increased with the square of the breaker height. Thus, cross-shore flow due to infragravity waves can be estimated with knowledge of the nearshore profile and incident wave conditions.
SEDIMENT TRANSPORT ON THE SOUTH-EAST AUSTRALIAN CONTINENTAL SHELF
Authors: Gordon Angus D. , Hoffman John G.
Published: June 2019

Engineering projects on the continental shelf off Sydney, Australia, have stimulated investigation into the sediment transport system of the shelf. Investigation activities associated with these projects have included: definition of sea bed morphology, sediment distribution and bedform characteristics; monitoring of steady and wave induced currents; wind data collection; suspended sediment sampling; bottom camera sediment movement investigations and analytical studies of sediment reaction to sea bed forcing functions. Sea bed velocity exceedence relationships for both wave oscillations and steady currents have been determined at depths of 24 m, 60 m and 80 m. Thresholds of sediment movement have been defined. Relative sediment transport computations have been undertaken and studies of suspended sediment concentration profiles are in progress so that absolute transport rates can be determined. The prevailing conditions, which include a mainly south bound current, are seldom sufficient to induce entrainment of shelf sediments. Transport events mainly result from major storms in the Tasman Sea which produce both high energy waves and north bound currents. Although these events are rare and short lived, the combined wave and current shear produced at the sea bed during the events gives rise to entrainment conditions which result in their dominance of the shelf sediment transport system.
DEPOSITIONAL EFFECTS OF OFFSHORE BREAKWATER DUE TO ONSHORE-OFFSHORE SEDIMENT MOVEMENT
Authors: Noda Hideaki
Published: June 2019

Physical parameters controlling the development of tombolo behind offshore breakwaters are clarified on the basis of the results obtained by laboratory tests. Especially, the depositional effects are evaluated by taking a permeable type structure into account. They are wave characteristics, sediment size, the water depth where the structures are to be placed and its dimension. The amount of sand deposition behind the structures is presented by non-dimensional parameters such as the relative distances from the initial shoreline to the structure and to the breaking point of waves, the ratio of the gap width to the wave length in deep water and the ratio of the length of the offshore breakwater to the wave length in deep water.
STUDY OF THE EVOLUTION OF DREDGED MATERIAL DISCHARGES BY MEANS OF RADIOACTIVE TRACERS
Authors: Tola F. , Caillot A. , Courtois G. , Gourlez P. , Hoslin R. , Massias J. , Quesney M. , Sauzay G.
Published: June 2019

The choice of a dumping area for dredged materials must be carried out taking into account the general movement of sediments in order to evaluate the risk they represent for the zone itself, the harbourworks and the coastal area* The use of radioactive tracers allows to study, in situ, transfer properties under tidal currents of fine sediments resuspended during the release, the distribution over the sea-bed of coarse particles and their future evolution due to currents and waves. In this way, parameters such as transport axis, mean velocity, dispersion, dilution and bed-load transport rates are determined- Four experiments which took place at OCTEVILLE, ANTIFER (FRANCE), SINGAPORE and ZEEBRUGGE (BELGIUM) during the ten past years illustrate the method.