bluuebunny/crossref_metadata_2025 huggingface dataset:
A PRE-DREDGING SAND MOBILITY STUDY USING A RADIOISOTOPE TRACER
Authors: Davison A.
Published: June 2019

The wave-driven movement of sand across the alignment of a proposed navigation channel was investigated using radioactive chromium-51 labelled tracer sand. The mean particle velocity and thickness of the mobile layer were determined over a two-month period, and an annual infill rate estimated. Wave height and period were measured concurrently. Despite two storms, during which near-bed oscillating velocities of 1.5 m s-1 were calculated the sand transport at 10 m (BMWL) appears to occur within the wave boundary layer. Onshore transport in the direction of wave propagation, due to mass transport velocity and wave asymmetry effects, was easily identified. Tidal currents up to 1.2 m s-1 (at 3 m above bed) had less than the expected effect on the tracer dispersion pattern.
EFFECT OF RIP CURRENT BARRIER ON HARBOR SHOALING
Authors: Sasaki Tamio O. , Sakuramoto Hiroshi
Published: June 2019

Prototype experiments on rip currents and sediment transport around structures were conducted at two fishery harbors on microtidal high energy beaches facing the Pacific Ocean. The purpose of the experiments was to examine the performance and mechanism of rip current barrier structures on harbor shoaling. Based on the results of five experiments, the wave breaker heights during which varied from 1.1 m to 3.0 m, it is concluded that shore-parallel rip current barriers are effective if their length is greater than the surf zone width and if they are located outside the surf zone. When the above conditions are satisfied, the rip current barrier is a cost-effective measure against shoaling of small craft harbors.
SHORELINE CHANGE AT OARAI BEACH: PAST, PRESENT AND FUTURE
Authors: Kraus Nicholas C. , Hanson Hans , Harikai Soichi
Published: June 2019

Large breakwaters and groins are being constructed at Oarai Harbor, Japan. As a result the beach is significantly deforming. The first part of this paper documents past and recent shoreline change at Oarai. The general characteristics of the offshore waves, breaking waves, and longshore current pattern are described and used to explain qualitative features of the observed shoreline change. The second part presents results of numerical simulations of shoreline change at the site which occurred over different time periods. The model includes three sources of wave diffraction, a rigorous formulation of the seawall boundary condition, and sand bypassing at groins. The modeling of historical shoreline change was reasonably successful. As an exercise in investigating problems associated with prediction, the model was used to forecast the shoreline position at the site five years from now. The prediction of the wave history was the main problem encountered. A simple intuitive method was devised to estimate the probable range in variation of the wave history, and the results are discussed in connection with the shoreline forecast.
QUANTIFICATION OF SHORELINE RHYTHMICITY
Authors: Garrow Holly C.
Published: June 2019

The study of beach morphology, for example, its changes with wave and tide conditions, is facilitated by the development of simple numerical values which characterize the morphology. Multivariate (EOF) analysis of topographic contour data is a means for determining important morphologic components which vary independently. If these components correspond to familiar shoreline features the researcher considers important, then the development of each component can be quantified by its significance, or weighting, in each sample. Alternatively, the components may be complicated and not useful in quantifying beach morphology. A study of these morphologic components, however, can provide insights into the dynamics of the beach system. If multivariate analysis produces complicated components, an alternative approach, of subjectively identifying shoreline characteristics of interest, can be taken. The characteristics may be the same as those frequently used in past studies, such as beach slope or sand volume. It is likely, though, that EOF analysis of topographic data will suggest more sophisticated characteristics which should be used. Some of these, for example, mean shoreline position or amplitude of a rhythmic shoreline, may be easily quantified, whereas, others such as longshore position of rhythmic features or cusp width relative to embayment width, may be more difficult to quantify. Both of these analysis approaches were applied to beach survey data obtained over a period of ten months (including the El Nifto winter of 1982/83) on Siletz Spit, Oregon. The shoreline was rhythmic with an 800-850 m wavelength throughout the duration of the study. Rhythmic topography has been associated with significant past beach and dune erosion at this site. Hence, it is of interest to describe the beach morphology quantitatively, and relate three dimensional beach changes to wave and tide conditions.
MODELLING OF THE DEPOSITIONAL PATTERNS IN HANGZHOU BAY
Authors: Jilan Su , Weiyi Xu
Published: June 2019

Prediction of depositional patterns in estuaries is one of the primary concerns to coastal engineers planning major hydraulic works. For a well-mixed estuary where suspended load is the dominant transport mode, we propose to use the divergence of the distribution of the net suspended load to predict the depositional patterns. The method is applied to Hangzhou Bay, and the results agree well qualitatively with measured results while quantitatively they are also of the right order of magnitude.
UNIFORM LONGSHORE CURRENT MEASUREMENTS AND CALCULATIONS
Authors: Visser P.J.
Published: June 2019

A description is given of laboratory experiments on uniform longshore currents and the comparison of the data with longshore current profiles predicted by a mathematical model. For the mathematical model it is assumed that longshore current generation takes place between the plunge line and the shoreline (instead of shoreward of the breaker line) and Battjes' (2,3) lateral friction model is applied. Good agreement between theory and laboratory data is achieved with realistic values of the bottom roughness.
ASPECTS OF WAVE CURRENT BOUNDARY LAYER FLOWS
Authors: Coffey Felicity C. , Nielsen Peter
Published: June 2019

Field measurements of steady current profiles under the influence of waves are described, including a technique for obtaining an extra independant estimate of the friction velocity. Field and laboratory measurements are analysed for the effect on apparent bed roughness by superimposing waves on a current. Finally the applicability of the eddy viscosity concept to combined flows is examined. The conclusion is that in general, different eddy viscosities must be applied to different flow components.
SOME TECHNIQUES TO CALCULATE DESIGN CURRENTS IN SHELF AND STRATIFIED COASTAL WATERS
Authors: Murray Stephen P. , Young Myron H.
Published: June 2019

Increasing use of marine environments for (a) petroleum-related structures (both explorational and production), (b) subsea mining (e.g., sulfur and salt), (c) brine disposal from onshore salt domes excavated for oil storage, and (d) offshore waste disposal has necessitated more frequent and more accurate predictions of current speeds and directions in coastal and shelf waters. No analytical techniques for such predictions of wind- and density-driven currents in coastal waters are presented at all in the Shore Protection Manual (1973). Wiegel (1964), however, does discuss wind-driven currents, but offers no modern methodologies for their application to coastal and ocean engineering problems. Simple predictive models as outlined in this paper are especially valuable in feasibility studies, where the expense of a field measurement program is not yet justified. The prediction of oil spill trajectories is another important application for these procedures.
A NUMERICAL HINDCASTOF STORM CURRENTS ON THE NORWEGIAN SHELF
Authors: Cooper Cortis K.
Published: June 2019

This paper describes an initial effort to model storm-driven currents and surge in the region indicated in Figure 1. The model results ultimately will be used in the design and operation of offshore oil platforms in the region. The study consisted of four major tasks: I) review of the data base and selection of the hindcast storms, 2) hindcast of the selected storms, 3) set-up and testing of the current model, and f) hindcast of currents for the selected storms.
REPRODUCTION OF NEARSHORE CURRENTS BY A MATHEMATICAL MODEL
Authors: Tanaka Hiroyoshi , Wada Akira
Published: June 2019

In order to cope with such environmental problems as shoreline change and diffusion of discharged warm water and contaminations in the surf zone, it is necessary to predict velocity vector field due to nearshore currents accurately. The present study is aimed at establishing a mathematical model applicable to the prediction of nearshore currents on actual coasts which have complicated bottom configurations. First, to investigate the mechanism of nearshore current generation hydraulic experiments were carried out. By the experiment it was made clear that the generation of a longshore current depends mainly upon a difference in mean water level in the longshore direction. After investigating estimation of radiation stress terms on the basis of the information obtained from the basic experiments a mathematical model of nearshore currents was developed and validity of the model was verified by both hydraulic model tests and field survey.
SIMULATION OF TIDES AND STORM SURGES IN THE GREAT BARRIER REEF REGION
Authors: Stark K.P. , Bode L. , Mason L.B.
Published: June 2019

The Great Barrier Reef Region which constitutes the north-eastern continental shelf waters of Australia, is an area that is subject to both large astronomical tides and the passage of tropical cyclones (hurricanes). One section of this area, centred on Mackay, is characterised by particularly high tides, with a springs range of order 10 metres. Numerical hydrodynamic modelling is used in the present study to: (a) simulate the M tide to investigate possible effects of the reef barrier on tidal amplification; (b) simulate the passage of a tropical cyclone across the continental shelf; (c) investigate the effect and consequences of non-linear surge/tide interactions. The recent discovery of a major shipping route through the reef in this area and the continuing development of natural resources makes a much more detailed understanding of the region's hydrodynamics essential for coastal engineering.
A TURBULENT TRANSPORT MODEL OF COASTAL PROCESSES
Authors: Sheng Y. Peter
Published: June 2019

A second-order closure model of turbulent transport and recent model applications to some problems of practical importance in coastal engineering are presented. Particular examples considered are the turbulent wave boundary layer under a linear and a cnoidal wave; current-wave interaction within the bottom boundary layer; mixed layer dynamics; wind-driven currents in a channel. Comparisons are made between the computed results and field/laboratory data.
PHOTOGRAMMETRIC MONITORING OF DOLOS STABILITY, MANASQUAN INLET, NEW JERSEY
Authors: Gebert Jeffrey A. , Clausner James
Published: June 2019

Photogrammetry has been applied as a technique to monitor the stability of dolosse on the Manasquan Inlet, New Jersey jetties. These jetties were rehabilitated between 1979 and 1982 with 16-ton steel-reinforced dolosse. The jetties have been exposed to a number of storms since 1982, including a design-level storm in March 1984. The photogrammetric measurements have provided a detailed record of the magnitude and direction of dolos movements in response to these storm events. Standard leveling techniques have been used to check the accuracy of the elevation data derived from photogrammetry. This paper describes the methods used in this monitoring effort and the results obtained from the photogrammetric measurements. Also presented are data on the structural integrity of the steelreinforced dolosse.
SHIP-WAVE ATTENUATION TESTS OF A PROTOTYPE FLOATING BREAKWATER
Authors: Nece Ronald E. , Skjelbreia Norman K.
Published: June 2019

Limited data are presented for the ship-wave attenuation of a prototype concrete pontoon floating breakwater. Results are compared with wave attenuation performance of a breakwater of identical crosssection and similar anchoring configuration as predicted by model tests using monochromatic waves. Field test procedures and limitations are described.
CASE HISTORY OF A SPACED PILE BREAKWATER AT HALF MOON BAY MARINA AUCKLAND, NEW ZEALAND
Authors: Hutchinson P.S. , Raudkivi A.J.
Published: June 2019

Half Moon Bay Marina is a privately owned small boat harbour located on the Tamaki Estuary of the Auckland Harbour. The marina was built in 1970 for 485 boats moored to floating marina berths, Fig. 1, and is sheltered by a spaced pile breakwater.
HURRICANE SURGE PROTOTYPE DATA COLLECTION
Authors: Flor Thomas H. , Scott Susan C.
Published: June 2019

Storm surges from hurricanes have even more devastating effects on human lives and property than the high wind velocities associated with such storms. Storm surge forecasts are necessary as a guide for emergency action to prevent disasters due to coastal flooding caused by tropical storms. The design and evaluation of coastal structures are also dependent on estimates of storm surge levels. Several numerical models have been developed that appear to reasonably predict the surge from storms of given size and intensity, but they sometimes differ significantly among themselves. A comprehensive data set is needed to quantitatively evaluate these models. These data will also provide a better understanding of coastal processes during periods of severe wave activity and high water levels, and will better define coastal and inland water elevation time histories, high water marks, and water velocity fields caused by tropical storms and hurricanes. The U. S. Army Engineer Waterways Experiment Station (WES), Coastal Engineering Research Center (CERC), under the sponsorship of the Office Chief of Engineers (OCE), has been involved for several years in a project entitled Hurricane Surge Prototype Data Collection Work Unit, the primary objective of which is to collect such a data set. In addition to the work being performed by CERC personnel, a cooperative program has been established with the Nuclear Regulatory Commission (NRC) and the University of Florida to collect surge data along the coast of Florida. A cooperative program has also been established with the National Ocean Service (NOS) to "harden" tide stations in the Gulf of Mexico and along the Atlantic Coast of Florida to survive hurricane forces and record the full range of anticipated surge levels. This paper describes CERC's long term, ongoing Hurricane Surge Prototype Data Collection project, as well as the data collected.
NEW TYPE BLOCKS FOR SEAWALL SLOPE PROTECTION
Authors: Toyoshima Osamu
Published: June 2019

Japan is a mountaineous country, and coastal areas have been looked upon quite valuable. In most cases, shorelines were slightly advancing until 1950, although there are some exceptional coasts which have been under continuous erosion for more than a thousand years. However, in the last thirty years, beaches began to be eroded one after another, and the countermeasure against beach erosion has become one of the most important problems in the national land preservation. Since the early 1960's, many seawalls against the beach erosion have been constructed. The table shows the amounts of the shore protection works constructed in the last twenty years.
STRUCTURAL DESIGN PROCEDURES FOR CONCRETE ARMOUR UNITS
Authors: Hall Kevin R. , Baird W.F. , Turcke D.J.
Published: June 2019

A rational design procedure for rubblemound breakwater protection which will ensure both the structural integrity and hydraulic stability of individual concrete armour units and the overall armour system is presented. The procedure involves new experimental techniques for measuring strains in model concrete armour units in a hydraulic model of a breakwater subjected to simulated prototype wave attack and analytical techniques for determining equivalent prototype loads on units. Selected design loads are used to define the resultant stress distribution to allow the designer to take the necessary measures to ensure the structural performance of the unit in a breakwater environment-
FATIGUE IN BREAKWATER CONCRETE ARMOUR UNITS
Authors: Burchath Hans F.
Published: June 2019

The reliability of rubble mound breakwaters depends on the hydraulic stability and the mechanical strength of the armour units. The paper deals with the important aspect of fatigue related to the strength of concrete armour units. Results showing significant fatigue from impact tests with Dolosse made of unreinforced and steel fibre reinforced flyash concrete are presented. Moreover universal graphs for fatigue in armour units made of conventional unreinforced concrete exposed to impact load and pulsating load are presented. The effect of fibre reinforcement and the implementation of fatigue in a stochastic design process are discussed.
SURVEYS OF COASTAL STRUCTURES USING GEOPHYSICAL TECHNIQUES
Authors: Dingler John R. , Anima Roberto J.
Published: June 2019

Coastal engineers have long relied upon bathymetric surveys to determine the extent of underwater damage to jetties and breakwaters. Though such surveys supply important information about variations in water depth around structures, they alone do not show in sufficient detail the nature of the material on the structure, the extent of subbottom features, or the nature of the subbottom upon which the structure sits. However, by conducting bathymetric surveys in conjunction with other remote-sensing techniques and diving observations, it is possible to obtain more complete knowledge of the subaqueous condition of coastal structures. During the summer of 1983 and the spring and summer of 1984, we conducted side scan sonar and shallow subbottom surveys in conjunction with bathymetric and diving surveys along three northern California coastal structures to determine the condition of the structures before extensive damage occurred. Then, we evaluated the applicability of the data collection techniques for condition surveys in general. Two of the structures surveyed are the parallel jetties that protect the entrance to Humboldt Bay, California, and the third structure is the outer breakwater at Crescent City, California. Bathymetric records and sonographs from Humboldt Bay show deep holes along much of the inside of the south jetty and off the heads of both jetties. The subbottom record from inside Humboldt Bay shows a subsurface fault, the extension of which would run under the south jetty. Sonographs from Crescent City show significant bedrock outcrops throughout the area outside the breakwater, making it difficult in places to identify the toe of the structure. The subbottom record shows that pockets of sand exist amidst the bedrock, but they are generally less than 2 m (6 ft) in thickness. We found that the side scan sonar is an excellent tool for defining the toe of the structure; also, when waves are low, it can be useful in determining armor types and the slope of structures Our subbottom system provided information on fault and bedrock locations; however, other systems need to be tested to see if any of them can locate buried armor near the structures.
RIGID BODY MOTION OF A FLOATING BREAKWATER
Authors: Miller Robert W. , Christensen Derald R.
Published: June 2019

Predictions of the dynamic response of a floating breakwater obtained from a frequency domain analysis are compared with full-scale field measurements. Those parameters prominently affecting accurate response predictions are identified and discussed.
HURRICANE ALICIA: STORM SURGES AND SHORE PROCESSES
Authors: Savage R.P.
Published: June 2019

Hurricane Alicia moved inland over the Texas coast during the night of August 17, 1983 creating waves and surges in the Gulf of Mexico and adjacent bays. Waves eroded beaches and dunes and surges overtopped low-lying areas of barrier islands and inland areas adjacent to the bays behind the barriers. A three-day survey of field evidence of water levels and flow directions was carried out one week after the storm. Physical evidence, such as the elevation of debris lines, water marks in buildings and debris caught on fences was used along with additional data from tide gages operating in the area to estimate the maximum flood levels and flow directions associated with the storm. Before and after aerial photography was used to obtain data on beach recession, retreat of the vegetation line behind the beach and extent of oyerwash deposits. The evidence gathered shows that the barrier islands were overtopped from front-to- back in some areas and from back-to-front in other areas with quite different results. There was little or no beach erosion to the left of the storm as it came ashore; however, serious beach erosion occurred for 18 miles (29.0 km) to the right of the storm and there was significant erosion for 55 miles (88.5 km) to the right of the storm. Maximum water levels in the Gulf, including the effects of normal tides and storm effects, were 9 to 11 feet (2.74 to 3.35 m) and maximum water levels along the nothern portion of Galveston Bay were 11 to 14 feet (3.35 to 4.27 m).
ASPHALT STABILIZATION OF RUBBLE SLOPES
Authors: Schmeltz E.J. , McCarthy M.J. , Lopez N.
Published: June 2019

During the spring of 1982 a new container terminal was under construction at the Port of Haina, Dominican Republic. Changes in design conditions due to damages to the protective breakwaters at the port entrance required modifications to the design of slope protection under the pier. The stabilization of the rubble slope was, in fact, a stop gap measure in that repairs would be instituted on the breakwaters in the near future. Due to a lack of suitable stone, the location of structural elements already in place and severe time constraints, an asphalt coating over relatively light weight rubble was selected to armor the slopes under the pier. The asphalt coating was prepared in a locally available batching plant and placed on-site using a crane equipped with a 4 cubic yard bucket. As a result of the use of the asphalt coating, construction delays were minimized and adequate slope protection was provided for the container pier without extensive design modifications. The purpose of this paper is to discuss the advantages and disadvantages of the use of asphalt in the construction of shore protection facilities in the context of the site specific application at the Port of Haina.
THE USE OF SAND IN BREAKWATER DESIGN
Authors: Van Damme L.V. , Kerchaert P.A. , Capentier R.L. , De Rouck J.N. , Bernard A.
Published: June 2019

The design scheme of the Zeebrugge Outer Harbour, Belgium, consists of two breakwaters protruding into the sea as far as 1,750 m beyond the existing mole or 3,000 m out from the coastline. The west outer breakwater is 4,280 m long, the east breakwater runs 4,030 m out from the sea-wall. The east outer harbour will accommodate terminals for liquid bulk products such as LNG. The west outer harbour will provide space to install two harbour basins to suit general cargo, hazardous cargo, container and ferry traffic. In the paper emphasis is put on the use of sand in the design of the breakwaters, firstly as part of the foundation by replacing the little resistant top layers by dumped sand, and secondly as part of the core, by dumping sand above the original sea-bottom. In as far as proposed criteria were not fulfilled, the dumped sand had to be compacted. Two methods are discussed : compaction by vibrating needles and compaction using explosives.
A REVIEW OF BREAKWATER DEVELOPMENT IN AUSTRALIA
Authors: Foster D.N.
Published: June 2019

Prior to 1970 rubble mound breakwaters in Australia were armoured with rock or concrete rectangular prisms. Model testing was rarely undertaken. During storms some damage to the breakwaters was tolerated with repairs being undertaken as and when necessary. This procedure is still successfully used today. However since 1970 there has been a move towards designing breakwaters to minimise or eliminate maintenance and to optimise costs. This paper reviews some of the less conventional developments that have taken place over this period, with references to reports and papers for those who wish to obtain more detailed information on any of the projects.
BREAKWATER ARMOR DISPLACEMENT THRESHOLDS: A POSSIBLE CORRELATION WITH CUMULATIVE WAVE ENERGY
Authors: Behnke Daniel L. , Raichlen Frederic
Published: June 2019

An extensive program of stability experiments in a highly detailed three-dimensional model has recently been completed to define a reconstruction technique for a damaged breakwater (Lillevang, Raichlen, Cox, and Behnke, 1984). Tests were conducted with both regular waves and irregular waves from various directions incident upon the breakwater. In comparison of the results of the regular wave tests to those of the irregular wave tests, a relation appeared to exist between breakwater damage and the accumulated energy to which the structure had been exposed. The energy delivered per wave is defined, as an approximation, as relating to the product of H2 and L, where H is the significant height of a train of irregular waves and L is the wave length at a selected depth, calculated according to small amplitude wave theory using a wave period corresponding to the peak energy of the spectrum. As applied in regular wave testing, H is the uniform wave height and L is that associated with the period of the simple wave train. The damage in the model due to regular waves and that caused by irregular waves has been related through the use of the cumulative wave energy contained in those waves which have an energy greater than a threshold value for the breakwater.
A DETAILED MODEL STUDY OF DAMAGE TO A LARGE BREAKWATER AND MODEL VERIFICATION OF CONCEPTS FOR REPAIR AND UPGRADED STRENGTH
Authors: Lillevang Omar J. , Raichlen Frederic , Cox Jack C. , Behnke Daniel L.
Published: June 2019

Ten years after it was completed, and intact as originally built, West Breakwater at Diablo Canyon on the central coast of California was severely damaged during a wave storm in January 1981. The paper describes uncommonly detailed site investigations that followed and the development of a large three-dimensional hydraulic model for discovering the specific mechanism that precipitated the damage, and then for verification of the effectiveness of concepts for rebuilding the breakwater to resist greater storm events than had been used for the original design. Unique procedures for modelling contorted terrain, for producing reflection-corrected irregular wave systems, for eliminating abnormal waves at the start and at the end of test runs are discussed. The tested final concept for reconstruction is described and surveyed results of closely packed Tribar armoring, as reconstructed in 1983-84, are illustrated. The authors conclude that investigations of problems involving wave attack on the termini of rubble mound breakwaters should always be undertaken with the aid of three-dimensional physical modelling unless owner and engineer are in a position knowingly to take large risks. Further, that physical modelling at suitably large scale is virtually mandated if the submerged terrain at a site is not regular.
ANALYSIS OF UPRIGHT STRUCTURE FOR WAVE DISSIPATION USING INTEGRAL EQUATION
Authors: Hagiwara Kazuhiro
Published: June 2019

A theoretical analysis using an integral equation derived for the unknown horizontal velocity component in a pervious wall is proposed for estimating the reflection and transmission coefficients of upright structures for wave dissipation, and various factors related to wave and structural conditions having influences on the wave dissipating characteristics are investigated for a breakwater with pervious vertical walls at both seaward and landward sides, In two-dimensional experiments, the theoretical results are in. good agreement with experimental data with respect to reflection and transmission coefficients, and therefore, the wave dissipating characteristics of upright structures for wave dissipation can be explained by the integral equation method theory.
COASTAL DESIGN CRITERIA IN SOUTHERN CALIFORNIA
Authors: Walker James R. , Nathan Robert A. , Seymour Richard J. , Strange R. Rea
Published: June 2019

Southern California was subjected to a series of severe winter storms in 198 3 that caused record damages to the coast. In the aftermath of the storms, emergency repairs were made and new designs were developed that responded to the severe conditions. These designs were often considerably more conservative than those previously undertaken. Agencies, owners, and engineers were compelled to use both higher design criteria and longer recurrence intervals to account for the wave characteristics and water levels that caused damages along the coast. This paper briefly discusses the unusual circumstances of the storm conditions and the associated damages. The primary purpose of the paper is to present new data that incorporates the effects of the 1983 winter storms to estimate the change in perception of what the wave climate and design criteria may be in this highly developed coastline. The results indicate that the design wave height for a given recurrence interval has increased approximately 26 percent, the wave periods are longer than previously used, and the severe storms tend to coincide with the extreme water levels. The engineer should consider the impacts of the 1983 winter storms in future designs. Despite the record damages, many structures survived. Merely using the highest water elevations and most severe waves of record may not be the most prudent design criteria. The concept of project life and economics must be employed to develop a design.
MEASUREMENT OF SURFACE WAVES FROM SUBSURFACE GAGE
Authors: Lee Dong-Young , Wang Hsiang
Published: June 2019

Wave measurement using subsurface pressure gage has many advantages, especially in coastal waters. However, there are some disadvantages associated with indirect measurement of surface waves. This paper deals with the problems in the recovery of surface waves from the subsurface pressure measurement. Two problems are examined: more exact recovery of the surface waves from subsurface pressure signal and a simple real time recovery of surface waves from the pressure record. The commonly used linear transformation from the subsurface pressure to surface elevation is evaluated and possible sources of error are examined. The effect of nonlinearity and effect of current are shown to be small in the intermediate water depth. For the case of shallow water where effects of nonlinearity and current are not negligible, a method of proper recovery of surface waves from the combination of pressure and current measurements is given. A simple method to recover the time series surface waves from subsurface record is proposed which enables speedy near real-time recovery of surface waves from pressure measurement using a microprocessor.
HYDRODYNAMIC FORCES ON A CIRCULAR CYLINDER DUE TO COMBINED WAVE AND CURRENT LOADING
Authors: Iwagaki Yuichi , Asano Toshiyuki
Published: June 2019

The hydrodynamic force acting on a circular cylinder in a wavecurrent co-existing field and its generating mechanism are discussed. This study focuses on the asymmetries of both the water particle movement and the resultant vortex property with respect to the cylinder, which produce inherent characteristics in the hydrodynamic forces in the wave-current co-existing field. First of all, the vortex property around a circular cylinder in the wave-adverse current co-existing field has been examined by flow visualization tests. It has been found that the vortex property depends on the flow characteristics around the trough phase when the wave-current composite velocity becomes maximum and can be represented with a newly proposed K.C. number for the co-existing field. Secondly, the characteristics of the in-line force has been made clear by evaluating the drag coefficient and the mass coefficient in the expanded Morison's equation for the co-existing field. These coefficients can be well arranged by (/CC. )-$, which is one of the newly proposed K.C. numbers, and their characteristics coincide with the existing results in the wave only field. The in-line hydrodynamic force in the co-existing field can be explained sufficiently by considering the vortex property in the same manner as clarified in the wave only field. Thirdly, the characteristics of the transverse force (lift force) are discussed in connection with the vortex properties. It has also been found that the fluctuating frequency of the lift force is synchronized with the loading wave frequency.
THE WAVE PRESSING PLATE FOR PROTECTING COOLING WATERWAYS OF COASTAL POWER PLANTS
Authors: Chow S.C. , Tang Frederick L.W. , Hwung H.H.
Published: June 2019

A horizontal plate laid on water surface to reduce the wave motion is proved to be effective theoretically and verified by model tests done at Tainan Hydraulics Laboratory. This principle has been put into practice on the northern coast of Taiwan for protecting a nuclear power plant cooling water intake against intruding waves. The design and construction of wave prevention works of such type are described succinctly in the paper. Also the effect of wave diminishing has been affirmed by measuring the respective waves heights outside and inside of the wave pressing plate.
ATTENUATION OF WAVE INDUCED OSCILLATION IN PORTS BY IMPROVING THE CONDITIONS AT THE HARBOR ENTRANCE
Authors: Kubo M. , Aoki S. , Segura J.J. Avitia
Published: June 2019

The authors developed the numerical method to calculate the wave height distribution around a pair of breakwaters with arbitrary shape of the edge. The effect of the resonators equipped in the breakwaters on the diffracted wave height is simulated by using this method. Simulated results show that the resonators have remarkable effect to reduce wave heights in a harbor. However, in the experiments, resonators are not so effective as predicted by the theory.
A SHALLOW WATER DIRECTIONAL WAVE RECORDER
Authors: Buchan S.J. , Steedman R.K. , Stroud S.A. , Provis D.G.
Published: June 2019

Shallow water wave theory shows that estimates of directional wave climate may be obtained from the measurement of near-bottom pressure and horizontal velocity components. Recent developments in low powered sensors and high density data loggers, incorporated into a bottom-mounted directional wave recorder, make the collection of directional shallow water wave data possible on a routine basis. The instrument is compact, robust, reliable and easily manageable from small craft, providing deployment capacities of up to four months. Analysis methods have been developed which provide for conversion of the recorded data to useful, convenient information.
SEDIMENTATION PATTERNS IN A TIDAL INLET SYSTEM MORICHES INLET, NEW YORK
Authors: Vogel Michael J. , Kana Timothy W.
Published: June 2019

A detailed study of the historical development of Moriches Inlet, Long Island (New York), was completed to determine the morphodynamic interaction of tidally influenced processes and the effects of man-made alterations on the inlet channel and affiliated flood and ebbtidal deltas. The south shore of Long Island in the vicinity of Moriches Inlet is a microtidal, wave-dominated (mixed-energy) environment. Characteristic of this setting, the inlet bisects a low-lying barrier island backed by an open bay and has a prominent flood-tidal delta. In this study, bathymetric charts of the inlet, bay, and barrier nearshore zones were contoured for analysis. Using a polar planimeter, the areas between isobaths from mean high water to the bottom surface were measured. This information was used to determine the volumetric distribution of sediment and water in the system. In addition, harmonic analysis was applied on digitized bay-tide records to ascertain the relationships of the semidiurnal overtide constituents. From the results, mean rise/fall duration differences, related to the conservation of mass, were calculated. The results of the quantitative spatial analysis indicate that Moriches Inlet was flood-dominant from breach in 1931 until closure in 1951. After reopening in 1953, the inlet became ebb-dominant as a result of inlet stabilization and extensive dredge-and-spoil operations in the inlet and bay. Good correlations exist between net sedimentation in the inlet with (1) bay-surface area change, (2) water storage capabilities of the flood-tidal delta, and (3) the cross-sectional area of the inlet. The relationship among these variables suggests that there is a system-wide response to the change in the hydrodynamics caused by man-made alterations, resulting in ebb dominance.
NUMERICAL MODELING OF SHORELINE EVOLUTION AROUND THE RIVER MOUTH
Authors: Lin Ming-Chung , Wang Jyh-Cherng
Published: June 2019

The river sediments transport into coastal water together with wave induced longshore sediment transport make shoreline evolution much complicated. Fig.l shows typical feature of shoreline shape around a river mouth. Recently there are some investigators treated this problem (Grijm, 1964, Bakker §Edelmen,1964; Komar,1973; Tsuchiya § Yasuda,1978),and had developed some mathematical or numerical models. This paper proposes a numerical model for predicting long-term shoreline evolution around a river mouth by incorporation certain river parameters into the Willis beach evolution model (1978). The proposed model is at first applied to four ideal cases to investigate its general characteristics and adaptability, and reasonable results are found. In our results the accretion on updrift side is faster than downdrift side under the oblique incident wave condition and the width of the river mouth increase steadily. These results are different from other approachs that the shoreline shape is always nearly symmetrical with respect to the centerline of the river mouth. Finally, as an field case application of the model, a numerical simulation of shoneline changes around the Cho-shui River mouth is performed and compared with field data.
LATERAL DISTRIBUTIONS OF WATER, SALT, AND SEDIMENT TRANSPORT IN A PARTLY MIXED ESTUARY
Authors: Uncles R.J. , Elliott R.C.A. , Weston S.A.
Published: June 2019

The transverse structure of the residual transport of water, salt and suspended sediment in the upper reaches of the Tamar Estuary is investigated. Data were obtained at three cross-sections for spring and neap tides. The transport for each variable is analyzed in terms of the governing physical processes.
THE EXCHANGE OF HATER IN FJORDS: A SIMPLE MODEL OF TWO-LAYER ADVECTIVE REACHES SEPARATED BY MIXING ZONES
Authors: Cokelet E.D. , Stewart R.J. , Ebbesmeyer C.C.
Published: June 2019

He propose a model for the two-layer, mean transport within a branched, recirculating fjord system. The recirculation is parameterized in terms of efflux/reflux coefficients at distinct mixing zones. The mass fluxes and efflux/reflux coefficients are determined from long-term salinity and current meter observations. The model provides a way to predict the mean concentrations of pollutants introduced within the system. An application to Puget Sound shows that different discharge sites markedly affect the concentrations landward of the sites themselves.
US ARMY CORPS OF ENGINEERS FIELD WAVE GAGING PROGRAM
Authors: Hemsley J. Michael
Published: June 2019

While the timely collection and reporting of climatological and environmental data have become routine in many countries, a similar capability for waves, currents, and coastal winds has not. The need for long-term, high quality wave data, in particular, has long frustrated the coastal engineer. In 1974, both Prof. Robert Wiegel and Dean Morrough P. O'Brien commented publically on the need for information on the nearshore wave climate comparable to data routinely available on many other natural phenomena. O'Brien further expressed his concern for improving the accuracy of wave forecasting and hindcasting techniques through comparison with reliable measurements (2). The need for characterizing the nearshore wave climate is much like the experience of conventional meteorological measurement programs. Along coastlines with high population densities, usage of the resource is intense. Ignorance of the processes at work carries a significant penalty. Past programs either have emphasized the collection of deepwater wave climatology or have been too regional or even site specific. With the Field Wave Gaging Program (FWGP), the US Army Corps of Engineers intends to collect the long-term, nearshore wave data that are necessary for planning, design, construction, operation, and maintenance of coastal projects.
OPTIMIZING DUMPING SITES NEAR DREDGED CHANNELS
Authors: Kogel Ulrich , Ohlmeyer Friedrich
Published: June 2019

To maintain the depth of the deepwater channel of the Elbe-Waterway extensive dredging has to be done permanently. Dumping should be optimized, choosing sites near the dredging area but with a small risk of recirculation of the dumped material. In order to estimate this risk field measurements with current meters and radioactive tracer tests in field and model were carried out.
CALIBRATION AND ADJUSTMENT PROCEDURES FOR THE RHINE-MEUSE ESTUARY SCALE MODEL
Authors: Van der Heijden H.N.C.M. , De Jong P. , Kuijper C. , Roelfzema A.
Published: June 2019

At the Delft Hydraulics Laboratory the hydraulic model of the Rhine- Meuse estuary has been rebuilt and extended after being destroyed by fire in 1979. The new model has been operational since the summer of 1982 for water quantity and water quality research. The present paper deals with the calibration and adjustment procedures for this hydraulic model. Successively the (physical) backgrounds for the calibration process, the techniques used for provision of boundary conditions and the procedures for adjusting flows and salinity distribution are discussed. Finally, the results of calibration and verification and the experiences gained on the employed techniques will be analysed.
COMPARISON OF TURBULENT LATERAL MIXING MODELS
Authors: McDougal William G. , Hudspeth Robert T.
Published: June 2019

A variety of different lateral mixing models have been employed in the equation of motion for determining wave-induced longshore currents. The equation of motion is cast into a general form which enables a comparison of the various models. Analytic solutions for longshore currents are developed for seven different mixing models. A nonplanar beach profile is employed because it has been found to be representative of many beaches and it allows for a distinction between offshore and depth scaling of eddies. The seven different mixing models include models which vary monotonically with horizontal distance offshore and models which change form at the breaker line. Numerical results indicate that the longshore current profile is rather insensitive to the form of the mixing model for nonplanar beach profiles.
IRREGULAR WAVE OVERTOPPING RATES
Authors: Douglass Scott L.
Published: June 2019

Methods for estimating wave overtopping of coastal structures are reviewed and compared with the very limited available data and with each other. The different methods yield results which can vary more than an order-of-magnitude. For vertical seawalls, the U. S. Army Engineer Shore Protection Manual method estimates more overtopping than Goda's method except in very shallow water. For sloped structures, the Shore Protection Manual method usually estimates less overtopping than Battjes' method and Owen's method. However, data for adequately evaluating how well these methods predict overtopping has not been published.
EFFECTS OF MEASUREMENT ERROR ON LONG-TERM WAVE STATISTICS
Authors: Le Mahaute Bernard , Wang Shen
Published: June 2019

The effect of sample size on confidence band in predicting the extreme wave height is related to the return period and the duration of the sample record length. An estimate of errors resulting from various methods of data acquisition is given. The uncertainties corresponding to various number of years of observation and various measurement errors are analyzed for various return intervals. It is shown that data accuracy and record length are equally important in long term wave predictions. At the present time, the determination of extreme event benefits more from relatively less accurate long-term hindcast calculation rather than short-term high quality measurements. In the long run, a long-term accurate measurement program is imperative if more definite descriptions of extreme events are sought.
ON A DESIGN WAVE SPECTRUM
Authors: Liu Paul C.
Published: June 2019

We propose the use of a generalized representation for acquiring a design wave spectrum. The generalized form, free from any predetermined coefficients and exponents, requires only significant wave height and average wave period as input for practical applications. The usefulness of this representation has been demonstrated with over 2000 measured deep-water wave spectra recorded from NOMAD buoys in the Great Lakes during 1981.
WAVE COHERENCE IN COASTAL WATERS
Authors: Hughes Steven A.
Published: June 2019

The spatial variability of the nearshore wave field is examined in terms of the coherence functions found between five closely spaced wave gages moored off the North Carolina coast in 17 meters depth. Coherence was found to rapidly decrease as the separation distance increased, particularly in the along-crest direction. This effect is expressed as nondimensional coherence contours which can be used to provide an estimate of the wave coherence expected between two spatial positions.
A NONLINEAR MODEL OF IRREGULAR WAVE RUN-UP HEIGHT A D PERIOD DISTRIBUTIONS ON GENTLE SLOPES
Authors: Sawaragi Toru , Iwata Koichiro
Published: June 2019

This paper discusses the probability distributions of irregular wave run-up height and period on gentle slopes. Assuming that the long period component appeared on the run-up oscillation corresponds to the incident envelope wave period, a nonlinear model to estimate the probability distributions of run-up heights and periods is proposed. Laboratory experiments on gentle slopes of 1/15,1/30 and 1/40, and field measurements on a natural sandy beach with swash slopes of 1/6 to 1/14 were performed to examine the proposed model. The proposed model is shown to agree with the experiments.
DESCRIPTION OF NATURAL SEA STATES: REQUIREMENTS TO THE REPRODUCTION IN MODELS
Authors: Lundgren H. , Davidsen Elias
Published: June 2019

In order to attain a satisfactory reproduction in physical and numerical models of Nature's sea states, much development of the description of these sea states has to take place. This paper gives a discussion (i) of the problems that can be considered as solved today, and (ii) of the problem areas where much research is still needed. Firstly, the paper presents the basic definition of the directional spread of energy (for a given frequency) as derived from a field record. This definition is necessarily a statistical one and leads directly to the determination in practice of the directional spectrum. Secondly, the parameterization of spectra is discussed and it is proposed to express one-dimensional storm spectra by means of the four -parameter F.1 .-spectrum, which is more manageable than the JONSWAP-spectrum. Thirdly, it is concluded that the first order components of any spectrum have random phases.
SHALLOW-WATER SPECTRAL WAVE MODELING
Authors: Jensen Robert E.
Published: June 2019

A parametric shallow-water spectral wave modeling technique is developed and is tested against extensive field measurements of wave height, period and spectral shape. The wave model considers wave growth and finite water depth mechanisms such as spectral wave shoaling, wave-bottom interactions, wave-wave interactions and wave breaking. The key to this approach is that the resulting wave conditions are provided by transformation mechanisms rather than transforming spectral components during wave propagation. Thus long-term wave hindcasts can be performed economically without the loss in accuracy.