bluuebunny/crossref_metadata_2025 huggingface dataset:
DEPTH OF DISTURBANCE OF SAND IN SURF ZONES
Authors: Gaughan Michael K.
Published: June 2019

A coring technique employed during wave action allowed accurate measurement of the depth of vertical mixing bm of fluorescent sand tracer grains within the surf zone of a gently sloping Pacific Ocean beach (beach slope tangent s = 0.012). The depth bm is the distance from the sediment surface to the lower limit of observed tracer grains within the inner portion of the core. Although this definition is only strictly applicable to a rectangular distribution of tracer concentration with depth, the bm results were quite similar to those using concentration-weighted depth averages of Crickmore (1967). For one winter regime experiment, vertical cross-sectional contour maps of tracer concentration normalized by the local core maximum were drawn with concentrations computed for each 0.4cm slice. Trends present are (1) in the onshore-offshore direction the maximum concentration is at the bed surface shorewards of the mid-surf position and 0.4 cm to 1.2 cm below the bed seaward of the mid-surf position, and (2) in the longshore direction (at the mid-surf position) the maximum concentration lies 0.4 cm to 1.6 cm below the bed surface. For spilling breaker heights Hb between 75 cm and 150 cm, histograms of bm were clearly different for spring/summer and fall/winter experiments: the mean and standard deviation (in parenthesis) are 0.5 cm (0.5 cm) and 1.1 cm (0.5 cm), respectively. These results are substantially less than both the 3.0 cm and the 20 cm to 40 cm disturbance depths per 100 cm of Hb reported by King (1951) and by Otvos (1965) and Williams (1970). The discrepancy with Otvos and Williams is due to the much different breaking process; in their experiments small breakers (Hb = 5 cm to 30 cm) plunged directly onto steep beach slopes (s = 0.1) causing large bm- The tracer grain's longer exposure to bottom stresses of passing surf bores may explain King's greater disturbance depths. Her sampling interval was one semi-diurnal tidal period T versus the span 0.02 T to 0.32 T in this study.
HF SKYWAVE RADAR MEASUREMENT OF HURRICANE WINDS AND WAVES
Authors: Maresca Joseph W. , Carlson Christopher T.
Published: June 2019

We measured significant wave height, and surface wind speed and direction for the first two Gulf of Mexico hurricanes of the 1977 season using a high frequency (HF) skywave radar. The radar measurements were made from California by using the SRI-operated Wide Aperture Research Facility (WARF). We recorded sea backscatter for hurricanes Anita and Babe, at distances more than 3000 km from the WARF, by means of single F-layer ionospheric reflection. We compiled real-time maps of the surface wind direction field within a radial distance of 200 km of the storm center, then estimated the hurricane position from these radar wind maps, and developed a track for Anita over a 4 day period between 30 August and 2 September 1977 as the storm moved westward across the Gulf of Mexico. The radar track was computed from 17 independent position estimates made before Anita crossed the Mexican coast, and was subsequently compared to the official track produced by National Hurricane Center (NHC). Agreement between the WARF position estimates and coincident temporal positions on the NHC smooth track was ±19 km. At approximately 0000Z on 1 September 1977, Anita passed within 50 km of the National Data Buoy Office (NDBO) open ocean moored buoy EB-71, and provided us with the opportunity to compare WARF estimates of the significant wave height, and surface wind speed and direction in all four quadrants of the storm with those made at the buoy. Agreement between the WARF and EB-71 measurements was within 10%. Two days after Anita crossed land, tropical storm Babe-a weaker, short-lived storm-developed. WARF estimates of the significant wave height, and surface wind speed and direction were made for selected regions of the storm.* No in situ wave measurements were available for comparison to the WARF measurements. WARF estimates of the wind speed were compared to wind speed measurements made at nearby oil platforms, and surface wind speeds computed from flight level winds (305 m) measured by a NOAA reconnaissance aircraft. Agreement was again within 10%. The purpose of this paper is to describe the capability of remotely monitoring hurricanes and other open ocean storms by using an HF skywave radar. We will describe the important aspects of the WARF skywave radar, the sea echo Doppler spectra, the method of analysis used to estimate the wave and wind parameters, and the accuracy of these radar-derived quantities.
THE NEARSHORE SEDIMENT TRANSPORT STUDY
Authors: Seymour Richard J. , Duane David B.
Published: June 2019

The models for predicting longshore transport of sediment along straight coastlines that are presently in general use were derived empirically from very sparse measurements of both the forcing function (waves and currents) and the response function (sediment motions). A detailed treatment of these data sets is contained in Greer and Madsen (1978). In addition to the generally unsatisfactory nature of the basic measurements upon which they were based, the models may be deficient because they fail to employ such potentially significant factors as wind stress, sediment size distribution, bottom slope and spatial variations in waves and currents, including the effects of rip currents. Although these models have served certain engineering needs, there is a strong measure of uncertainty in the coastal engineering community about their general applicability. Certainly, because they are empirical rather than physically reasoned models, there is no rational means for extending their usefulness to predicting transport where coastlines are not straight -- such as the case of a tidal inlet. The economic impact of sediment transport in the nearshore regime is enormous and the need for improved predictive tools appears to be universally accepted. To be most useful, these improved models must be globally applicable. This implies very strongly that they must be based upon a thorough understanding of surf zone dynamics and the details of the response of the sediment. The surf zone flow fields are highly complex and nonlinear, implying an equally complex and difficult system of sediment responses. Characterizing the entire forcing and response functions simultaneously requires large and expensive field measurement programs that greatly exceed the present state of the art of measurement and analysis.' The approach of the last two decades of single investigators working at laboratory scale or in the ocean with a few single point measurements would not appear to ever meet these needs. However, the present costs for coastal dredging and shoreline protection, which can be measured in billions of dollars on a world scale, argue for a major undertaking to develop better predictive tools. In an attempt to satisfy these needs, an ad hoc group was formed at the Fifteenth Coastal Engineering Conference in Honolulu to plan a large scale and coordinated series of investigations leading to improved sediment transport predictive models. Less than a year later, the Nearshore Sediment Transport Study was initiated under the sponsorship of the Office of Sea Grant.
SEDIMENT MOTION CAUSED BY SURFACE WATER WAVES
Authors: Davies A.G. , Wilkinson R.G.
Published: June 2019

This paper describes an experimental study of sand motion on the seabed caused by surface water waves. The observations were made close to a beach, but outside the breaker zone and in a location where steady currents were small. Measurements of water velocity components were made at various heights above both rippled and flat beds, together with measurements of the pressure gradients at the seabed, in order to examine the threshold of motion of the natural coarse sand ( © so ** 1.14mm). This motion was monitored with an underwater television system. The flow conditions were predominantly laminar and no flow separation occurred above the lee slopes of the ripples. Sediment motion was of 'bed load' type and was confined to the crests when the bed was rippled. This motion has been found to be caused by waves having an orbital velocity amplitude (measured in the free stream flow) of about one half of that required to cause motion on a flat bed of the same material. Wherever possible the threshold measurements have been compared with results obtained in the laboratory. The relative importance of forces on the seabed induced by velocity and pressure gradients has been assessed,, It appears that the latter effects are of little or no importance in situations of the kind described, as suggested elsewhere in the literature.
LITTORAL DRIFT ALONG BAYSHORE OF A BARRIER ISLAND
Authors: Wang Yu-Hwa , Chang T.H.
Published: June 2019

A barrier island is an easily recognized geographical land feature along the south-east Atlantic and Gulf of Mexico coasts of the United States. It is characterized by a large ratio of length to width. It has a bay on one side and an ocean on the other. The inlets, on the ends, connect the bay to the ocean. The sand movement along the bayshore side is subjected to steeper and shorter waves which respond to local wind conditions. The physical boundary constraint of a bay is also different from open coast shorelines. Virtually no information exists with regard to the littoral drift rate on a bay shoreline. This paper tries to answer the question of whether or not the drift on the bay shoreline is different from that of the open coast since it is under different wave climates and physical constraints.
SEDIMENT LOAD UNDER WAVES AND CURRENTS
Authors: Willis D.H.
Published: June 2019

A technique is proposed for calculating sediment load, the mass concentration of sediment in motion, under combinations of waves and currents. The technique is based on the unidirectional flow method of Ackers and White, Ref. 1. The calibration of the technique against measurements of sediment load under waves has only just begun.
A MODEL STUDY OF ALONGSHORE SEDIMENT TRANSPORT RAT
Authors: Kamphuis J.W. , Readshaw J.S.
Published: June 2019

Alongshore sediment transport rate was studied in a 3-dimensional mobile bed coastal model and was found to depend on the beach profile and rate of wave energy dissipation in addition to the normal wave and sediment parameters. Alongshore sediment transport rate was found to be strongly related to the surf similarity parameter, a single parameter simplistically describing beach profile and breaker type.
Complete Proceedings - Single PDF Download
Authors: ASCE ASCE
Published: June 2019

On behalf of the Organizing Committee for this 16th International Conference on Coastal Engineering, it is my special privilege as its Chairman to welcome you all very heartily here in the Congress-Center Hamburg to inaugurate a week of lectures and discussions on the manifold problems of Coastal Engineering. The Organizing Committee is very happy about the large number of participants being 621 up to now coming from 41 countries all over the world.
SOME IMPLICATIONS OF RECENT ADVANCES IN WAVE THEORIES
Authors: Chaplin J.R. , Anastasiou K.
Published: June 2019

Calculations using the 'Design Wave' approach in coastal and offshore engineering begin with the specification of wave conditions usually in terms of a wave height, wave period and mean water depth. These three dimensional parameters are sufficient to define all the wave characteristics uniquely if a number of assumptions are adopted, including those of periodicity in space and time, absence of viscosity, and twodimensional flow. Although these assumptions result in an enormous simplification of waves in the ocean, the ultimate idealised conditions hold some attraction in providing a standard description of wave mechanics for design purposes. Once the design wave approach has been adopted, it follows that the engineer needs to ensure that the theory which he uses to analyse waves generates results equivalent to those of the most accurate theory currently available. There are in engineering use several wave theories (e.g., Airy, Stokes 5th order, Cnoidal, Stream Function) by means of which required wave properties can be computed from an initial wave specification on the basis of ideal conditions. Unfortunately, none of these theories is exact and in general they disagree, most significantly in conditions of shallow water or high wave steepnesses. The differences between them have stimulated comparative studies based on boundary condition errors (Dean, 1970) and experimental data (Le Mehaute et al, 1968), leading to recommendations on the use of specific theories for given conditions. However, the value of these comparisons has been somewhat limited by the absence of an accurate solution to the problem valid over the whole range of interest. Such a solution has now been brought nearer by the work of Cokelet (1977), and it is the purpose of this paper to study the implementation of Cokelet's theory and other recent theories in an engineering context. The paper does not make any contribution to the analysis itself but is concerned with applications, and the question whether such developments should influence current engineering practice. Previously, the wave theory offering greatest analytical accuracy and widest range of application was the Stream Function Theory of Dean (1965).
THE BEACH IMPROVEMENT PROGRAMME : NEW SOUTH WALES
Authors: Philip Neale A. , Whaite Philip H.
Published: June 2019

The Coastal Engineering Branch of the Public Works Department N.S.W administers the Beach Improvement Programme, a programme of works with an average annual expenditure of one million dollars, for the improvement of the State's public recreational beach amenities. Priority is given to beaches with highest usage, resulting in the first two years' funds being allocated to the densely populated coastal strip between Newcastle and Wollongong. Priority is also assigned to various types of works:- 1. Preservation, conservation or restoration of the beach itself by sand nourishment, dune stabilisation, seawall demolition; 2. Erosion control where appropriate, by seawall and revetment construction and land acquisition; 3. Provision of facilities such as car parks, access roads, dressing sheds and toilet blocks; 4. Beautification such as grassing and tree planting. The near city beaches in Sydney, Newcastle and Wollongong have mostly been fully developed with seawalls and promenades behind the beach berm, while in outer Metropolitan areas, the beaches have been left in a more natural state, with some development such as car parks and dressing pavillions on or behind the sand dunes.
WAVE FORCES ON AN INCLINED CIRCULAR CYLINDRICAL PILE
Authors: Shigemura Toshiyuki
Published: June 2019

This paper describes experimental results on the in-line and lift forces acting on inclined circular piles which are placed in two different planes: (1) a vertical plane parallel to the direction of wave propagation; and (2) a vertical plane parallel to the wave crest. The in-line and lift force formulas for an inclined pile are formulated by referring to the conventional Morison and lift force formulas, respectively. Stokes third order wave theory is used for the estimation of flow kinematics induced around a pile. Based on these formulas, the time-independent and time-dependent values of the drag, mass and lift coefficients are determined by using several methods. Further, the time dependent coefficients are expanded into Fourier series which consist of several significant components. Reliability of these coefficient values are studied by examining the relative deviation of the predicted wave forces based on these coefficient values from the measured ones. The analysis finds that relative deviations of the in-line and lift forces exceed in many cases 15% and 100%, respectively, when the time-independent coefficients are used for the prediction of wave forces, but that they are reduced to 5% and 15%, respectively, when the time-dependent coefficients are used for it.
STABILITY ANALYSIS OF SEAFLOOR FOUNDATIONS
Authors: Yamamoto Tokuo , Suzuki Tasumasa
Published: June 2019

Stability analysis of homogeneous and inhomogeneous seabed foundations under attack by storm waves are made by calculating the wave induced effective stresses. Wave induced effective stress analysis of homogeneous seabed is made using the theory previously developed by the senior author which is based on the poro-elastic theory by Biot. Effective stresses in inhomogeneous seabeds induced by waves are calculated by approximating an inhomogeneous bed by many layers of homogeneous soils each of which has different geotechnical properties of soils. A good agreement is obtained between the theory and the pore pressure data in situ field measurements. For a given wave length, it is found that there exists a most unstable thickness of homogeneous seabed when the seabed thickness is one-fifth of the wave length. As a realistic example of an inhomogeneous bed, the effective stresses in a typical seabed formation at the Mississippi Delta area of the Gulf of Mexico under the attack of design storm waves are calculated. The numerical results indicate that the storm waves induce a continuous submarine landslide which extends as deep as 9 m from the mud line. Numerical calculations also indicate that such landslides and liquefaction of seabeds can be prevented by placing a layer of concrete blocks or rubbles on the top of the seabeds.
FULL SCALE TRAILS OF DOLOSSE TO DESTRUCTION
Authors: Burcharth Hans F.
Published: June 2019

It is well known that the relative dynamic strength of unreinforced slender concrete units decreases as the size increases. Big units can resist relatively smaller movements than small units. When model tests of cover layer stability are performed the determination of the damage criterion that should be adopted must therefore be based on knowledge of the dynamic strength of the corresponding prototype units. With the purpose of establishing a relation between the size and the dynamic strength of unreinforced units some full scale tests to destruction of 1.5 and 5.4 t units were performed. The set up and the procedure of the tests which simulates the impact from rocking of the units and from concrete pieces that are thrown against the units are designed to make a comparison between the behaviour of units of different sizes possible. The test method is described and proposed as a standard method. The theoretical expression for the dynamic strength is compared with the test results and it is shown that if the units are allowed to move there is an upper limit for the size of unreinforced units where a balance between the hydraulic stability of the cover layer and the strength of the units exists. Different ways of improving the strength of the units are discussed on the basis of the results from tests with different types of concrete. The tests included an investigation of the influence of reinforcement, and of different types of concrete and surface cracks on the performance of the units.
SEAWALLS IN DEEP SEAS
Authors: Nagai Shoshichiro , Kakuno Shohachi
Published: June 2019

Features in wave overtopping of two new types of seawalls designed to be built in considerably deep sea conditions are presented herein. One of those is the seawall of concrete caisson with a parapet wall and armor blocks on the top of the caisson, and another one is the seawall with a slitted box-type wave absorber. The former type of seawall has successfully been constructed in the Japan Sea and the Seto Inland Sea and is also to be constructed at a site directly exposed to an open sea of the Pacific Ocean in 1980 and 1981. The latter type of seawall was proposed in 1977 after numerous experiments and has been under construction in the Port of Osaka since 1978. The results of the experiments on the wave overtopping over the slit-type seawall were compared with the calculated results, obtained by an analysis in which the wave overtopping over a parapet wall was considered similar to the phenomenon of flow over sharp-edged weirs having time-dependent overflow-head. The calculated curves obtained are in good agreement with the experimental results. The designs of these two types of seawall are also presented herein.
SITING AND DESIGN CRITERIA OF DOCK STRUCTURES IN THE MARSHALL ISLANDS
Authors: Noble R.M. , Leslie K.C. , O'Day D.
Published: June 2019

In the summer of 1978, a siting/design investigation for dock structures (Marshall Islands Dock Project) was conducted at 15 atolls within the Marshall Islands group (see Figure 1). The Marshall Islands are within the U.S. Trust Territory of the Pacific Islands (TTPI), located in the North Pacific. The Marshall Islands Dock Project is part of the Capital Improvements Program currently underway in the Marshalls. The program, aimed towards making the Marshall Islands more selfsufficient in preparation for their independence in 1981, includes the construction of low cost dock structures for use by the design vessels described in this paper to load/unload agricultural products, supplies, and passengers. This study did not include the feasibility of this approach versus other alternative loading/unloading approaches. This investigation included site selection, development of design criteria, and the design and alignment schemes for 12 new dock structures. In addition, design criteria and plans were developed for the upgrading of three existing dock structures. The site selection was performed using a multidisciplinary approach which considered environmental, sociological, and archaeological impacts, in addition to the usual technical site selection. This paper only discusses the technical considerations to site selection. Overall responsibility for the project was assumed by the Pacific Ocean Division of the U.S. Army Corps of Engineers on behalf of the Government of the Trust Territory of the Pacific Islands. Our work was performed for Alfred A. Yee & Associates, Inc., the structural engineer and prime contractor for the project, and in collaboration with R. M. Towill Corporation.
LITTORAL DRIFT OF SAND NEAR PORT OF OARAI
Authors: Mizumura Kazumasa
Published: June 2019

To study the main direction of littoral drift of sand near the Port of Oarai, field observations were made. Through the analyses of the results the following facts were obtained. (1) The relative changes of foreshore gradients alongshore were correlated with the characteristics of beaches. (2) By investigating sand grain sizes on the coast the predominant direction of littoral drift of sand could be illustrated. (3) The direction of littoral drift of sand was almost coincident with the main nearshore currents.
NON-RESONANT WAVE AGITATION IN SMALL CRAFT HARBOURS
Authors: Kamphuis J.W. , Smith D.A.Y.
Published: June 2019

A model study of wave agitation in small craft harbours was performed using a square and a rectangular marina basin subjected to monochromatic waves. Wave agitation was measured in up to 273 points within the marina basin and overall wave energy levels were calculated from these measurements for 4 different wave periods, 6 different entrances and 5 different lengths of energy absorbing sections along the perimeter walls. These values were compared and found to correspond well with a rather simple theoretical expression.
NEW JETTIES FOR TUNG-KANG FISHING HARBOR, TAIWAN
Authors: Su Chi-Fu
Published: June 2019

Tung-Kang Fishing Harbor, which is about 16 km to the south of Kaohsiung Harbor, is a river harbor on the south-west coast of Taiwan. This harbor is located at the estuary of the Niu-Pu River, which meets the Tung- Kang River and the Kao-Ping River on the north side, (see Fig. 1) The original north and south jetties were constructed in 1959. Because the entrance is located at the meeting of the three rivers and the water depth at the entrance is shallower than that in the breaking zone, the entrance is easily chocked with sand during the summer season when the south-west wind and waves are strong. Therefore, dredging is always necessary to maintain the required depth. On. the other hand, because of the increasing number of fishing boats and deeper draft, the port cannot function effectively. There-fore, how to keep the required water depth at the entrance and to obtain a wider and stable water basin is an urgent problem with this harbor. Based on the sounding of 1973, the littoral drift is mainly from the south. In the next year the construction of a 176 m long new south jetty was begun to protect the entrance and to facilitate the sedimentation study. In 1975, the Taiwan Fisheries Consultants was appointed to undertake the investigation and long-term planning work. This project includes littoral process study, planning, model test and design. Finally it is recommended that an adequate layout of south and north jetties can solve the problem of accretation of the harbor entrance. The purpose of this paper is to describe some aspects with emphasis on how to prevent the shoaling of the entrance channel located at the meeting of the rivers.
WAVE ENERGY DISTRIBUTION IN AN ESTUARY
Authors: Barthel Volker
Published: June 2019

A field investigation program on waves in the Weser Estuary, German Bight of the North Sea, was started to learn about the complex wave climate in this region. The comparison of results in the various locations shows that most of the' wave energy is transferred from deep water across the reef region to the wadden area. The comparison of spectra in the different sites and the parametrization of these multipeak- spectra gives another feasibility to describe estuarine waves.
TIDAL INLET BEHAVIOURAL ANALYSIS
Authors: Nielsen A.F. , Gordon A.D.
Published: June 2019

For many years stability theories have been used both to design inlets and to appraise the performance of them. There are a variety of approaches to the formulation of stability criteria ranging from the purely empirical (Stevenson, 1884 - cited by Bruun & Gerritsen, 1958; O'Brien, 1931; Bruun, 1977) to the generalised analytical (Escoffier, 1940; Bruun & Gerritsen, 1958; Keulegan, 1967; O'Brien and Dean, 1972). In 1966 a seemingly small perturbation made to the inlet of Wallis Lake resulted in significant changes to the estuary. The direct application of existing stability theories was of marginal value in explaining these changes and predicting the stable regime that the estuary may ultimately reach.
SEDIMENTATION PROCESSES IN TIDAL CHANNELS AND TIDAL BASINS CAUSED BY ARTIFICIAL CONSTRUCTIONS
Authors: Renger E. , Partenscky H.W.
Published: June 2019

Tidal basins and tidal rivers especially in areas of agricultural and industrial interest are more and more regulated and improved for different reasons such as draining, disposal of waste water, shipping and storm flood protection. This is - up to now - mainly done by dams, dikes, training walls, channel dredging, storm surge control barriers, etc .. In general, the tidal motion (tidal range and tidal velocities) in the whole system is affected by these man-made changes in the cross-sectional area of the tidal river. The hydrographical effects caused by such artificial constructions in tidal rivers have been outlined in the papers of H.G. WITTMER and al.(12). However, the morphological consequences of such measures are largely unknown. The analysis of a real system, such as the EIDER-Estuary at the German Bay, which was affected by both a reduction in its tidal prism by the construction of a tidal dam in 1936, and by a reduction of its cross-sectional area by a storm surge control barrier in 19 72, must therefore be highly appreciated. In general, the most important changes of a tidal regime are caused by two different types of artificial influences: - horizontal reductions of the tidal volume (for instance by damming-off a tidal river) - vertical reductions of the cross-section(s) at any particular part of the tidal regime (for instance by storm surge control barriers or training walls) In both cases the existing equilibrium conditions are disturbed and the relationships between the horizontal and vertical components of the tidal motion are distorted more or less according to the distance from the structure.
COMMENTS ON TIDAL ENTRANCES ON SANDY COASTS
Authors: O'Brien Morrough O.
Published: June 2019

The information necessary for computation of the tidal prism is available in charts and tide tables for many inlet-bay systems. Empirical correlations have been developed by Le Conte in 1905, O'Brien in 1931 and 1969, and others, which showed the flow area to be a unique function of the tidal prism for the sets of data studied. However, the data underlying these correlations were derived from inlets with semidiurnal tides, typical of the Atlantic and. Pacific Coasts of the United States. Jarrett in 1976 showed that such correlations are not valid for diurnal and mixed tides, such as occur along the Gulf Coast. Stevenson in 1874 pointed out that the scouring capacity of the tide must include the number of tidal cycles per year. Since the number of tidal cycles in any period of time is inversely proportional to their duration, the integrated scouring capacity of the tidal flow through an inlet channel should be independent of the duration of the tidal cycle and should depend primarily on the tidal discharge. If the maximum rate of tidal discharge (Qmax) and the variation of discharge throughout the tidal cycle are identical for two inlets subjected to tidal cycles of different duration, the scouring capacity of the two inlets would be the same over equal periods of time. The conclusion is that Qmax should provide a more generally valid basis for correlation with the flow area than does the tidal prism alone and one which may be valid at hydraulic model scale and for inlets maintained by the seiching of nontidal lakes, as at Duluth. Bruun (1978) used the correlation of the flow area with 0 in his studies.
A COASTAL INLET WITH FIXED BED AND MOBILE SIDES
Authors: Nelson R.C. , Keats A.J.
Published: June 2019

The coastal inlet dealt with in this paper has a fixed bed of exposed rock and mobile side boundaries of sand that overlies the bed rock platform. The work was undertaken to investigate the response of the throat section to natural hydraulic and meteorological events and to observe the nature and rate of recovery of the inlet after the more extreme events. These events included sea and swell states, wind, freshwater flood flows and short term changes in mean sea level (storm surges or meteorological tides). The three year study involved the inlet at the mouth of the Barwon River, Victoria, Australia (see Figure 1). The work forms part of a continuing study to assess the impact of engineering works on the stability of the estuary and inlet, and was required to assist in delineating the natural inlet variability from that due to engineering works. The study described here looked specifically at the inlet throat section which refers to the short narrow waterway connecting the estuary with the sea. The inlet throat section at Barwon Heads is well defined and is shown in Figure 1. The inlet itself is free of training walls and is normally flanked by sandy beaches. However, the depth of the inlet is limited by a bed of rock (see Figure 2), there being, in effect, unlimited mobility on a side boundary only.
SATELLITE APPLICATIONS ON A COASTAL INLET STABILITY STUDY
Authors: Wang Yu-Hwa
Published: June 2019

It is known that longshore drift of alluvial material occurs along sandy barrier islands. Inlets between these barrier islands intercept the normal littoral drift, resulting in a net loss of sand from the beaches. During a flood tide, sand is brought into the inlet and part of it is retained to form the inner bar; during ebb cycle, part of the sand is jetted out into the ocean to form an outer bar. The reversing flows of flood and ebb cycles may also cause deposition or scouring on the bottom of inlet channels. There are two sets of parameters pertinent to the behavior of inlets. The first set deals with the changes in the dynamic bottom configuration (i.e. the movement of inner and outer bars, the choking or scouring of the inlet channel). The second set of parameters regards the driving forces of the coastal system (i.e. wave climate, tide, wind and currents). Understanding the interrelationship of these two sets of parameters lead to the solution of stabilizing the inlet. The time sequential dynamic interrelationships and natural tendencies of inlets are we11-portrayed on available Landsat imageries. The techniques of mapping the sand bars and their movements are traditionally done by a sounding boat and survey team. The derived point and line information are then used to produce the contour map of the bottom. Extensive interpolations are needed because many details between the points and lines are missing. The operation is expensive and the procedures are time consuming. Techniques using remote sensing can be used to monitor the changes that take place, reducing costs and increasing efficiency. Eventhough standard procedures have not yet been established, the satellite sensing of bottom features has progressed considerably in recent years. Sherman (1975), Middleton and Barber (1976), Hubbard (1977), and Lyzenga and Thomson (1978) all demonstrated that it is possible to correlate the radiance values of multi-spectral images, such as Landsat imagery, with the depth related information in shallow water. The present study is one more example of such an effort.
MECHANISMS OPERATING AT A JETTIED RIVER ENTRANCE
Authors: Druery Bruce M. , Nielsen Alexander F.
Published: June 2019

Between October 1976 and July 1977 a northern rubble mound jetty was constructed at the mouth of the Hastings River, transforming the entrance from a single to a double jettied system. Prior to the jetty construction the entrance was characterised by the presence of a substantial swash bar (alternatively called an ebb delta marginal shoal) which was a continuous feature over 100 years of hydrographic survey records. However, construction of the northern jetty triggered an unprecedented onshore movement of the swash bar. This movement was well documented by a field monitoring programme incorporating hydrosurveys, aerial* photographs, tidal gaugings, sediment sampling, float tracking and nearby wave rider buoy information. A semi-quantitative model was developed to aid understanding and quantification of the macro sedimentary processes associated with this phenomenon. The model demonstrated that the sudden reduction of the swash bar was due to the disruption of a circulation of sand which had previously aided the dynamic stability of the bar. The quantitative predictions of the model agreed well with subsequent entrance behaviour. The philosophical development of the model and its findings are discussed in detail. In the literature there is a general lack of attempts to quantify the sediment transport relationships between the gross morphologic features of tidal entrances. This paper presents a methodology for assessing the sedimentary process at tidal entrances.
STUDY ON VORTEX CURRENT IN STRAIT WITH REMOTE-SENSING
Authors: Onishi Sotoaki , Nishimura Tsukasa
Published: June 2019

With rapid increases of industrial activity in present time, water pollution in the coastal environment has "become an urgent problem to cope with. This problem is especially serious in enclosed bays or inland seas. Hydrodynamic character of the strait connecting the inland sea to the open ocean must be understood well in order to analyse the diffusion of pollutants in the Inland sea, because its character determine boundary conditions in the mathematical models of the water pollution problem. So far however, it is seemed that the main efforts exerted by coastal engineers have concentrated mainly on the development of mathematical models, lacking satisfactory knowledge of the boundary conditions through field measurements. One reason of this state is resulted from the fact that the relating phenomena in the field are of too large scale, in general, to perform the field measurements. Connecting with this point, the authors present in this paper, that remote-sensing technology is very useful to get information of the hydrodynaniical phenomena occurring in the water body around the strait. To show the above, the authors selected as an object of the study , Naruto Strait in the Seto Inland Sea, which is world famous for the existence of rapid tidal currents and dynamic vortices. Remote-sensing data both from the airplanes and from a space satellite Landsat are analysed with the aid of theoretical considerations and hydraulic mo-del tests to disclose the behavior of the vortices of various scales and the roles of them in the sea water mixing phenomena at the strait.
MOORING FORCES INDUCED BY PASSING SHIPS - MEASUREMENTS IN PROTOTYPE
Authors: Haffke K.
Published: June 2019

In the present study the mooring systems of four bulk carriers which were moored at a jetty located parallel to a navigable water were investigated with special regard to forces due to passing ships. The objective of this study was to verify in praxi the present knowledge of moored vessels berthed at more protected sites and to prove proposed models of forcing functions by passing ships as well as numerical models for the computation of ship mooring systems. For that purpose the mooring forces and also those data which characterized the properties of the mooring systems were recorded. On the basis of the also recorded wind and current data and the data of the passing ships with which the external forces could be estimated the mooring forces were computed. These computed forces are compared with the measured mooring forces.
RESONANCES OF COASTAL WATERS BETWEEN PERTH AND GERALDTON (WESTERN AUSTRALIA)
Authors: Allison H. , Grassia A. , Litchfield R.
Published: June 2019

Sea-level oscillations along the Western Australian coast, with periods in the range of 20-40 mins, have considerably greater amplitudes between Perth and Geraldton than at other locations along the coastline. It is shown that amplification of these oscillations is due to resonance in the near shore basin formed by the shore and a submerged reef-chain parallel to and 5 km from the shore. The rigorous analytical solution for the resonance frequencies is obtained for the two-dimensional hydrodynamic model. Comparison with results from spectral analysis of recorded oscillations indicates a satisfactorily agreement with the theory. Statistical estimation of damping of the observed oscillations indicates that the predominant resonance in the first mode is sharp, having the quality factor Q=10.
MODELLING OF PLANFORM INFLUENCE ON CIRCULATION IN HARBOURS
Authors: Falconer Roger A.
Published: June 2019

A two dimensional numerical model has been developed which is capable of predicting the tidal water elevations, depth averaged velocity components and horizontal concentration distributions in narrow entranced harbours and marinas. Particular attention has been paid to the numerical treatment of the convective accelerations where, as a result of narrow harbour entrances and the general nature of planform geometries, the resulting highly non-uniform flow fields can readily lead to nonlinear instabilities and unstable numerical solutions. In order to check the validity of the numerical results, a comprehensive study was carried out to compare, with scaled laboratory model studies, the predicted tidal velocity fields and flushing characteristics for a number of rectangular harbours of constant planform area but different length to breadth ratios. The experimentally measured average per cycle exchange coefficients and the observed mean water level pathlines agreed reasonably well with the corresponding numerically predicted exchange coefficients and depth averaged velocity fields. The results of both the numerical and laboratory model studies confirmed conclusively that the maximum gross flushing characteristics occurred within a rectangular harbour when the length to breadth ratio was close to unity. Also, further tests showed that the insertion of impermeable barriers as a possible means of increasing the flushing efficiency proved to be unsatisfactory.
ON A ROLE OF THE INTERFACIAL FROUDE NUMBER
Authors: Kashiwamura Masakazu
Published: June 2019

As already stated in the previous conference, the fresh-water flow which passes through a river mouth horizontally into the sea, exhibits a special characteristic due to the effect of buoyancy. Its dynamics belongs, essentially to the same category with the transonic flow in aerodynamics. The interfacial Froude number plays a dominant role in this case, as well as the Mach number does in the transonic gas flow. The supercritical zone, in which the interfacial Froude number exceeds unity, occupies the sea surface with some area, in response to a degree of the discharge amount of the fresh water. This zone begins at the river mouth and stretches in the offshore directions over the sea, accompanied with a lateral growth. As is well known, on the other hand, supersonic zones are sometimes formed partially along an airfoil, or in a tube with a varying crosssection, if they are placed in a subsonic gas flow. Those two different phenomena have been proved to be identical dynamically with each other [KASHIWAMURA and YOSHIDA 1978], [KASHIWAMURA 1979]. There have been a great number of researches in order to obtain an analytical solution of the transonic flow, in the past several decades, but there seem still many difficulties to attain a complete solution, except some particular cases such as a stream-lined approximation of immersed bodies being possible. Considering such circumstances, it may also be difficult for the present problem to be solved completely, although it Has not been decided yet to be impossible. The present author describes the process of his efforts for obtaining an analytical solution and its results, from a view point of the inspection on an applicability of the hodograph method, and its modification to this problem. In spite of incompleteness, they provide us several findings which are useful to understand the dynamics of the outflow of the fresh water. In addition to those, a few examples of field data concerning the horizontal distribution of the interfacial Froude number around a river mouth, and some experimental results are presented.
EXPERIMENTAL STUDY OF THE BUOYANT SURFACE JET WITH THE PRESENCE OF BOTTOM BOUNDARY AND CROSS CURRENT
Authors: Safaie B.
Published: June 2019

The problem of buoyant surface jet (BSJ) is relevant from the practical standpoint to the discharge of cooling water of power plants into the receiving water bodies. The buoyant surface jet has extensively been studied by numerous investigators both theoretically and experimentally. Most studies have been concerned with the problems of BSJ discharged horizontally into a surface of a deep ambient water with or without cross current. From a practical standpoint, however, the design engineers are often confronted with the design of thermal outfalls in the coastal regions which are frequently shallow and have the boundary effects. Few investigators have studied the problem of BSJ discharged horizontally over slopping bottom into quiescent receiving water (1), (2), (4), (5), (6), and (7). However, no information on the foregoing problem with moving ambient water is available. The purpose of this paper is (a) to present the experimental results of BSJ which is discharged over slopping bottom into moving ambient water, and (b) to see the degree of error which is introduced by applying the deep water integral models to the case of a buoyant surface jet with a bottom boundary.
CONSIDERATIONS IN THE DESIGN OP AN OFFSHORE DATA COLLECTION PROGRAM
Authors: Cooper Cortis , Febres German
Published: June 2019

In-situ data collection in the ocean is costly and unpredictable even when the program is relatively well planned and executed. Despite these inherent difficulties, designers of a data collection program will find little guidance in the literature to assist them in the planning and organizational stages. Some papers "have been published discussing particular aspects of a program such as instrumentation, and others have described some of the general experiences of various programs. However, there has been no attempt to conceptualize the process of design of an offshore data collection program and this is one of the purposes of the discussion which follows. The various steps involved in design are identified, ordered, and discussed in some detail. Specific examples are drawn from the authors' experiences with several offshore monitoring programs. The work presented is most applicable to the collection of oceanographic and meteorological (O/M) data since the authors' experience is essentially restricted to this particular type of data collection. However, it is suspected that a significant portion of the aspects considered would apply to offshore programs involving the collection of other types of data such as geotechnical. Many of the ideas presented originate from experience with two large 0/M programs conducted by Instituto Tecnoligico Venezolano del Petroleo (INTEVEP). One of the studies extended over the Orinoco Delta region of Venezuela with an area of roughly 150 x 150 kms. The program began in late 1977 and ended in the spring of 1979. O/M data were taken at nine stations in the region. Figure 1 shows the region and the location of the stations involved in the study. The second INTEVEP program was started in the summer of 1979 and covers the contiguous coastline of Venezuela, approximately 1200 x 100 kms. O/M data are being taken at nine stations during the three year life of the program. Figure 2 shows the coast of Venezuela and the station locations.
ENVIRONMENTAL ASPECTS OF OIL AND GAS PIPELINE LANDFALLS IN NORTHEAST SCOTLAND
Authors: Krueger William Ritchie
Published: June 2019

Oil and gas pipelines from the North Sea have reached the northeast coast of Scotland from offshore production platforms. The pipelines date from 1973 to 1976. The environmental effects of these pipelines are compared as are the relationships between engineering work, environmental impact assessment and planning procedures. There is also a discussion of methods used to protect and restore these three landfall areas.
WATER MOVEMENT STUDIES REQUIRED FOR PORT PLANNING
Authors: Dandy Graeme C. , Mills Desmond A. , Hinwood Jon B.
Published: June 2019

Some of the factors involved in the design of a programme of measurement and analysis of current, temperature and salinity data, required for the environmental assessment of an estuarine port, are considered in the context of a study carried out in the Port of Melbourne, Australia. The study was undertaken as part of the Port of Melbourne Environmental Study, 6 Webb Dock Marine Study which was aimed at assessing the present regime and the effects on the marine and coastal environments resulting from the construction of Berth 6, Webb Dock in Hobsons Bay (Figure 1). To this end, integrated investigations of water movement, water quality, coastal processes and marine ecology were conducted. Although the results presented in this paper are specific to Hobsons Bay, the approach taken is of general applicability to the environmental assessment of proposed physical changes in complex estuaries and embayments. In such cases, the prediction of changed patterns of currents and density structure is a key element in assessing likely changes in other environmental factors such as water quality and the biota. In general, an environmental study of water movement in an estuary will involve some measurements of the existing conditions of current, temperature and salinity, followed by appropriate analyses of these data to enable the likely changes to be predicted.
REPORT ON THE DAMAGES TO THE SINES BREAKWATER, PORTUGAL
Authors: Baird William F. , Caldwell Joseph M. , Edge Billy L. , Magoon Orville T. , Treadwell Donald D.
Published: June 2019

Possible contributing factors to the 1978 failure of the massive main breakwater at Sines, Portugal are presented in a selective summary of the report of the Port Sines Investigating Panel. A failure scenario involving the impact breakage of unreinforced concrete armor units is developed.