WorldWideScience

Sample records for breakwaters

  1. Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Frigaard, Peter

    1987-01-01

    at The Hydraulics Laboratory, Department of Civil Engineering, University of Aalborg. The object was to study the stability/erosion of the breakwater head and the trunk, the latter exposed to both head-on and oblique irregular waves. To avoid too many parameters a simple breakwater geometry and only one class...

  2. The Design Of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1994-01-01

    The main purpose of a breakwater is to reduce the waves in an area. More often than not the objectives are to obtain acceptable mooring and manoeuvring conditions for ships, but breakwaters are also used for beach protection. Moreover, many of the principles related to the design of breakwaters...... and erosion, not only close to the structures but also at a distance....

  3. Design of the Ciervana Breakwater

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Frigaard, Peter; Uzcanga, J.

    1995-01-01

    A major expansion of Port Bilbao includes some 4.5 km of breakwaters in water depths up to 28 metres. Construction cost is approximately 190 mill. USD. The paper presents the lay-out and the cross section of the most exposed breakwater section.......A major expansion of Port Bilbao includes some 4.5 km of breakwaters in water depths up to 28 metres. Construction cost is approximately 190 mill. USD. The paper presents the lay-out and the cross section of the most exposed breakwater section....

  4. Rubble Mound Breakwater Failure Modes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Z., Liu

    1995-01-01

    The RMBFM-Project (Rubble Mound Breakwater Failure Modes) is sponsored by the Directorate General XII of the Commission of the European Communities under the Contract MAS-CT92- 0042, with the objective of contributing to the development of rational methods for the design of rubble mound breakwate...

  5. Analysis of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Mettam, J.D.; Allsop, N.W.H.; Bonafous, P.

    Working Group 12 was set up to consider the analysis of rubble mound breakwaters with a view to achieving a better understanding of safety aspects. The working group decided to develop the practical application of risk analysis in the design of rubble mound breakwaters by using partial coefficien...

  6. On Optimum Design of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2005-01-01

    Because breakwaters belong to the most important and costly coastal structures it is of importance to optimise the design with respect both to function and lifetime costs. The paper presents a short discussion on choice of type of breakwater and functional aspects. The main content of the paper i...

  7. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough...

  8. Optimum Safety Levels for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    2005-01-01

    statistics and structure response. The study comprises the influence of interest rate, service lifetime, downtime costs and damage accumulation. Design limit states and safety classes for breakwaters are discussed. The results indicate that optimum safety levels are somewhat higher than the safety levels......Optimum design safety levels for rock and cube armoured rubble mound breakwaters without superstructure are investigated by numerical simulations on the basis of minimization of the total costs over the service life of the structure, taking into account typical uncertainties related to wave...

  9. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1994-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...

  10. The Lessons From Recent Breakwater Failures:developments in breakwater design

    OpenAIRE

    Burcharth, Hans F.

    1987-01-01

    The design and construction of breakwaters is a classical task in coastal engineering. Breakwaters have been built, damaged and repaired for hundred of years. It is generally believed that coastal engineering science has improved a lot during the last 20 years. The profession was therefore taken by surprise when a series of major breakwater failures occurred very recently in a four year period.

  11. The PIANC Safety Factor System for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2000-01-01

    The paper presents a summary of the recommendations for implementation of safety in breakwater designs given by the PIANC PTC IT Working Group No 12 on Analysis of Rubble Mound Breakwaters with Vertical and Inclined Concrete Walls. The working groups developed for the most important failure modes...

  12. Breakwaters with Vertical and Inclined Concrete Walls

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk

    Following the PIANC PTC II working group on Analyses of Rubble Mound Breakwaters it was, in 1991, decided to form Working Group (WG) n° 28 on "Breakwaters with vertical and inclined concrete walls" The scope of the work was to achieve a better understanding of the overall safety aspects...

  13. The Lessons From Recent Breakwater Failures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    The design and construction of breakwaters is a classical task in coastal engineering. Breakwaters have been built, damaged and repaired for hundred of years. It is generally believed that coastal engineering science has improved a lot during the last 20 years. The profession was therefore taken...

  14. Breakwater for the Port of Dande, Angola

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Francesco, Comola

    This report deals with a 3-D model test study of the new breakwater at Porto de Dande, Angola. Part of the trunk and the roundhead were tested in 3-D for stability, overtopping and run-up under various sea conditions. The model testing of the breakwater in a 3-D basin was requested for some...

  15. The Design Philosophy for a Vertical Breakwater

    DEFF Research Database (Denmark)

    Vrijling, J. K.; Burcharth, H. F.; Voortman, H. G.

    2000-01-01

    A consistent risk-based design philosophy for vertical breakwaters is proposed. The design philosophy consists of a two-step approach. The first step is the definition of the main function of the breakwater, which leads to a definition of failure. The second step is the choice of the acceptable...

  16. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...... the construction stage. Anyway, it is seldom that a fair amount of rocks of mass larger than 10-15 t can be produced, even in good quality quarries. If heavier blocks are needed concrete armour units or vertical structures must be considered....

  17. 2-D Model Test of Dolosse Breakwater

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou

    1994-01-01

    ). To extend the design diagram to cover Dolos breakwaters with superstructure, 2-D model tests of Dolos breakwater with wave wall is included in the project Rubble Mound Breakwater Failure Modes sponsored by the Directorate General XII of the Commission of the European Communities under Contract MAS-CT92...... of the method of placing and packing the blocks on the hydraulic stability. The Dolosse were more carefully put on the slope and the hydraulic stability of such slope was compared with that of the more randomly packed slope. The whole experiment was carried out in the period of August - November 1993...

  18. Innovative Breakwaters Design for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Stagonas, D.; Müller, G.

    2012-01-01

    This paper intends contributing to an economically and environmentally sustainable development of coastal infrastructures by investigating the possibility of combining together breakwaters and Wave Energy Converters (WEC). The latter change the wave energy to electricity, which may serve both...... the rubble mound breakwaters and seawalls related activity and the energy demand of small human communities. Wave loadings and overtopping on a seawall and rubble mound breakwater with front reservoir are discussed on the basis of physical 2-D model tests carried out at University of Southampton (UK...

  19. On Front Slope Stability of Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2013-01-01

    The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison...... test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height......, relative berm width, method of armour stone placement, and hydraulic parameters. The formulae should cover the structure range from statically stable berm breakwaters to conventional double layer armoured breakwaters....

  20. Numerical prediction of shoreline adjacent to breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Mahadevan, R.; Chandramohan, P.; Nayak, B.U.

    Existing mathematical models for prediction of shoreline changes in the vicinity of a breakwater were reviewed The analytical and numerical results obtained from these models have been compared Under the numerical approach, two different implicit...

  1. Introduction to Coastal Engineering and Breakwaters

    NARCIS (Netherlands)

    Bijker, E.W.

    1972-01-01

    Collegedictaat f11a and f11b. Lecture notes, short waves, waves near shoreline, coastal formation, sediment transport by waves, coastal protection, delta coasts, muddy coasts, tidal rivers, density currents, breakwater design.

  2. Design and construction of mound breakwaters

    Directory of Open Access Journals (Sweden)

    Josep R. Medina

    2014-08-01

    Full Text Available This paper describes the evolution of design techniques applied to mound breakwaters as well as some key tools, equipment and construction techniques. The influence of the theoretical and laboratory research is analyzed in detail, from the pioneering research by Iribarren eighty years ago to the construction of single-layer armored breakwaters in recent decades. The economic optimization and the new embodied energy and carbon concepts associated to the construction of mound breakwaters are studied. New concepts as well as the invention of new armor units are examined as is their impact based on the observations from small-scale physical experiments and the relevance of the equipment and logistic constraints to explain the evolution of the way mound breakwaters have been designed and built over time.

  3. Stability of a Perforated Quarter Circle Breakwater

    Directory of Open Access Journals (Sweden)

    ArkalVittal Hegde

    2015-12-01

    Full Text Available Many new types of breakwaters have been constructed of lateto fulfill the ever increasing demand of marine traffic. The quarter circle breakwater (QBW is a recent type of breakwater developed on the lines of an earlier semicircular breakwater (SBW. QBW may be without perforations, seaside perforated or both sides perforated. A series of laboratory experiments were conducted in a two dimensional monochromatic wave flume on an emerged seaside perforated non-overtopping quarter circle breakwater model to study its stability against sliding. The scale of the model was 1:30. A range of incident wave heights (Hi and wave periods (T were generated in the flume simulating the wave climate off Mangaluru coast in the Karnataka State of India. The experimental data so collected was analyzed to understand the variation of the non-dimensional stability parameter with incident wave steepness for different values of dimensionless depth parameter In the end a nomogram was developed for computing the sliding stability of the breakwater.

  4. Coastal Response, a system of detached breakwaters

    Science.gov (United States)

    García Ortiz, Isabelo; Negro Valdecantos, Vicente; Santos López, Jose; Esteban, María Dolores

    2017-04-01

    The coastline's sedimentary response in the form of a tombolo or semi-tombolo (salient) as a result of the construction of detached breakwaters is an aspect that should be known in the design phase so that these marine structures may be properly designed. In achieving an ecological, social and economic value, such areas must also be properly managed. All design methods in existence since Dean (1978) are mainly based on hypotheses formulated from geometric studies on existing formations. No relationship at all is established with climate and littoral dynamics typical of the location (only Suh and Darlymple (1987) and the Japanese Ministry of Construction (1986) present relationships depending on wave variables). Neither has the influence on systems with more than two breakwaters been studied. These methods are not fully adapted to the cases existing on the Spanish Mediterranean littoral. The lines of investigation as proposed by L. Bricio and V. Negro (2010) were continued with for this study. These researchers developed a method for dimensioning isolated, detached breakwaters and their semi-tombolo or tombolo associated formations using all the characteristics of the site (energy, geometric and structural), specific climate and geomorphology and littoral dynamics' characteristics. This methodology is currently acknowledged and accepted in works undertaken on the Spanish Mediterranean littoral. A linear regression was obtained in the investigation undertaken on the 18 detached breakwater systems along the whole of the 1670 km of the Spanish Mediterranean littoral using the proposals made by L. Bricio and V. Negro. The adjustment of R2 ≥ 0.90 was used for the sandy, tombolo formations behind all the detached breakwater systems between several non-dimensional monomials displaying the most representative characteristics of the site. L/H12 + (2ṡB)/G =12,15ṡ(X/Xc)+7,3231 X: Distance of breakwaters from coastline Xc: Distance from coastline where the closure depth

  5. Rehabilitation of Yzerfontein breakwater by Dolos armour units

    CSIR Research Space (South Africa)

    Letsie, Masupha M

    2015-07-01

    Full Text Available The Yzerfontein breakwater was constructed in 1950 and has since been subjected to extensive deterioration. In order to extend the lifespan of the breakwater a maintenance program was to be carried out. Various options are described...

  6. Choice of Breakwater Type and Optimum Safety Levels

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2009-01-01

    Breakwaters belong generally to the more expensive part of port and coastal protection structures. The fact that the main function of breakwaters is to provide shelter for wave action defines automatically the two main problems related to breakwater engineering, namely construction in often very ...

  7. Coastline Protection by a Submerged Breakwater

    Science.gov (United States)

    Valentine, B. D.; Hayatdavoodi, M.; Ertekin, R. C.

    2016-02-01

    Coastal communities are in danger of the impact caused by storm surge and waves. Storm surge brings the water level to a higher elevation and farther inland. This rise in water level increases the chance of a higher number and larger set of waves approaching shorelines, and it can potentially devastate the coastal infrastructure. In this study, we evaluate the performance of a submerged, horizontal breakwater located near shore. Unlike other types of breakwaters, such as the ones that extend to the surface, either fixed or floating, a submerged horizontal breakwater does not create any visual distraction or limit most of the recreational and commercial activities in the nearshore areas. The Level I Green-Naghdi (GN) nonlinear water wave equations are utilized here to study the wave transformation over a submerged breakwater that is located in shallow water. The GN theory is based on the theory of directed fluid sheets and assumes an incompressible and inviscid fluid; no assumption on the rotationality of the flow is required. In this approach, the nonlinear boundary conditions and the averaged conservation laws are satisfied exactly. The reflection and transmission coefficients due to nonlinear shallow water waves are determined implementing two approaches which use Goda's (1976) and Grue's (1992) methods. The results are compared with the existing laboratory experiments, and close agreement is observed overall. Preliminary results of the performance of the breakwater on dissipating storm waves during Hurricane Ike (2008), approaching the shore of Galveston, Texas, are presented.

  8. Numerical wave interaction with tetrapods breakwater

    Directory of Open Access Journals (Sweden)

    Dentale Fabio

    2014-12-01

    Full Text Available The paper provides some results of a new procedure to analyze the hydrodynamic aspects of the interactions between maritime emerged breakwaters and waves by integrating CAD and CFD. The structure is modeled in the numerical domain by overlapping individual three-dimensional elements (Tetrapods, very much like the real world or physical laboratory testing. Flow of the fluid within the interstices among concrete blocks is evaluated by integrating the RANS equations. The aim is to investigate the reliability of this approach as a design tool. Therefore, for the results' validation, the numerical run-up and reflection effects on virtual breakwater were compared with some empirical formulae and some similar laboratory tests. Here are presented the results of a first simple validation procedure. The validation shows that, at present, this innovative approach can be used in the breakwater design phase for comparison between several design solutions with a significant minor cost.

  9. Numerical wave interaction with tetrapods breakwater

    Directory of Open Access Journals (Sweden)

    Fabio Dentale

    2014-12-01

    Full Text Available The paper provides some results of a new procedure to analyze the hydrodynamic aspects of the interactions between maritime emerged breakwaters and waves by integrating CAD and CFD. The structure is modeled in the numerical domain by overlapping individual three-dimensional elements (Tetrapods, very much like the real world or physical laboratory testing. Flow of the fluid within the interstices among concrete blocks is evaluated by integrating the RANS equations. The aim is to investigate the reliability of this approach as a design tool. Therefore, for the results’ validation, the numerical run-up and reflection effects on virtual breakwater were compared with some empirical formulae and some similar laboratory tests. Here are presented the results of a first simple validation procedure. The validation shows that, at present, this innovative approach can be used in the breakwater design phase for comparison between several design solutions with a significant minor cost.

  10. Toe rock stability for rubble mound breakwaters

    NARCIS (Netherlands)

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges.

  11. Wave transmission by suspended pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Mani, J.S.; Jayakumar, S.

    ratio of 0.46), a 5% reduction in incident-wave height can be achieved. The cost and performance of conventionally adopted pile breakwater (involving a row of closely spaced piles driven on the seabed) were compared with the present system...

  12. Experimental Investigation on Caisson Breakwater Sliding

    DEFF Research Database (Denmark)

    Ruol, Piero; Martin, Paolo; Andersen, Thomas Lykke

    2014-01-01

    This note presents wave flume experiments, carried out at Aalborg University, measuring the horizontal sliding distance of a vertical breakwater in 1:40 scale. Horizontal and uplift wave induced pressures were accurately measured simultaneously with the caisson movements. Caissons of different we...

  13. Shoreline response to detached breakwaters in prototype

    NARCIS (Netherlands)

    Khuong, T.C.

    2016-01-01

    An accurate prediction of shoreline changes behind detached breakwaters is, in regard to the adjustment to the environmental impact, still a challenge for designers and coastal managers. This research is expected to fill the gaps in the estimation of shoreline changes by developing new and

  14. Reliability Analysis of Geotechnical Failure Modes for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    2000-01-01

    Vertical wall breakwaters are usually designed as concrete caissons placed on the top of a rubble mound foundation or a rubble bedding layer. The purpose of the breakwater is usually to protect the area behind the breakwater from being flooded by large waves. The area protected can for example...... be a harbour of small or large importance, an important industrial area or a heavily populated coast line. This implies that vertical wall breakwaters are used under quite different conditions and therefore the consequences of a complete or partial failure also are very different. This implies...

  15. Partial Safety Factors for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1995-01-01

    lifetimes from 20 to 100 years and different qualities of wave data. A code of practice where safety is taken into account using partial safety factors is called a level I code. The partial safety factors are calibrated using First Order Reliability Methods (FORM, see Madsen et al. [1]) where...... in section 3. First Order Reliability Methods are described in section 4, and in section 5 it is shown how partial safety factors can be introduced and calibrated. The format of a code for design and analysis of rubble mound breakwaters is discussed in section 6. The mathematical formulation of the limit......On the basis of the failure modes formulated in the various subtasks calibration of partial safety factors are described in this paper. The partial safety factors can be used to design breakwaters under quite different design conditions, namely probabilities of failure from 0.01 to 0.4, design...

  16. Ashtabula Breakwater Common Tern (Sterna Hirundo) Nesting

    Science.gov (United States)

    2016-05-01

    Breakwater Common Tern (Sterna Hirundo) Nesting By Thomas J. Fredette, Richard J. Ruby , Paul Bijhouwer, Burton C. Suedel, Michael Guilfoyle, Marleen...young terns. This analysis used worst- case conditions, which are most likely to occur during the fall or winter, and thus there should be relatively...from falling over the edge. Figure 8. Gull roosting deterrent spikes on fence post caps. ERDC TN-EWN-16-1 May 2016 9 Tern decoys purchased

  17. Monitoring and maintenance of breakwaters which protect port entrances

    CSIR Research Space (South Africa)

    Tulsi, K

    2009-07-01

    Full Text Available to annually monitor the main breakwaters of the South African ports to ensure they remain in good condition. This paper presents a brief description of the performance of the dolos breakwaters in South Africa, and the filed monitoring techniques used to record...

  18. The use of physics engines in quantifying breakwater damage

    CSIR Research Space (South Africa)

    Gledhill, Irvy MA

    2013-07-08

    Full Text Available The response of proposed breakwater packing strategies to incident waves is usually tested and evaluated in a model hall. There is currently also increasing interest in using numerical simulations to model both the packing of a breakwater, and its...

  19. State-of-the-Art of Designing and Constructing Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Hedar, P. A.; Ouemeraci, H.

    Berm breakwaters are different from ordinary rubble mound breakwaters. A conventional rubble mound breakwater is required to be almost statically stable for the design wave conditions, while the berm breakwater has traditionally been allowed to reshape to a statically stable or a dynamically stable...

  20. Fatigue in Breakwater Concrete Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    1985-01-01

    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......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...

  1. Pore Pressure Measurements Inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    2004-01-01

    The present paper presents pore pressure measurements from large scale model tests performed at the Large Wave Channel, Hannover, Germany and small scale model test performed at the Hydraulic & Coastal Engineering Laboratory, Aalborg University, Denmark. Information on pore pressure attenuation...... and wave damping in the core and important for the scaling of core materials in small scale hydraulic models. The main objectives are to study and examine the wave damping in the core of rubble mound breakwater models. the acquired test results are compared with results available from the literature...

  2. Application of Reliability in Breakwater Design

    DEFF Research Database (Denmark)

    Christiani, Erik

    methods to design certain types of breakwaters. Reliability analyses of the main armour and toe berm interaction is exemplified to show the effect of a multiple set of failure mechanisms. First the limit state equations of the main armour and toe interaction are derived from laboratory tests performed...... by Bologna University. Thereafter a multiple system of failure for the interaction is established. Relevant stochastic parameters are characterized prior to the reliability evaluation. Application of reliability in crown wall design is illustrated by deriving relevant single foundation failure modes...

  3. Floating Breakwater Field Experience, West Coast

    Science.gov (United States)

    1982-07-01

    OF PAGES Kingman fluildiny,, Fort Belvoir, Virginia 22960) 64 IS. N-loSSYiNG AGENCY NAME a AOONE5Sit dIove mnI tem CoatUa 3oW.) IS. SECURITY CLASS...speeds of 60 knots are common. However, the annual summary of winds at Japon - * liski Airport (see Table) indicates that 40-knot winds are rare...section in the initial breakwater layout broke during a storm (D. Miller, personal communication ). This connection has been eliminated by the new alinement

  4. Functional design of breakwaters for shore protection: empirical methods

    National Research Council Canada - National Science Library

    Rosati, J.D

    1990-01-01

    ... for the primary purpose of shore protection. The data set used to develop each design method is discussed, and the empirical procedures are evaluated based on available Corps-built breakwater project data...

  5. Flow and Turbulence at Rubble-Mound Breakwater Armor Layers under Solitary Wave

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2015-01-01

    . To isolate the processes involved with the flow in the porous core, experiments were conducted with increasing complexity. Specifically, three parallel experiments were performed including (1) an impermeable smooth breakwater slope, (2) an impermeable breakwater slope with large roughness elements added...... to the breakwater, and (3) a porous breakwater where the porous core was added below the breakwater front. One breakwater slope of 1:1.5 was applied. In this paper the focus is on the details of a single sequence of wave approach, run-up, and rundown. To isolate this sequence the experiments were performed applying...

  6. Interaction of Submerged Breakwater by a Solitary Wave Using WC-SPH Method

    Directory of Open Access Journals (Sweden)

    Afshin Mansouri

    2014-01-01

    Full Text Available Interaction of a solitary wave and submerged breakwater is studied in a meshless, Lagrangian approach. For this purpose, a two-dimensional smoothed particle hydrodynamics (SPH code is developed. Furthermore, an extensive set of simulations is conducted. In the first step, the generated solitary wave is validated. Subsequently, the interaction of solitary wave and submerged breakwater is investigated thoroughly. Results of the interaction of solitary wave and a submerged breakwater are also shown to be in good agreement with published experimental studies. Afterwards, the effects of the inclination and length of breakwater as well as distance between two breakwaters are evaluated on damping ratio of breakwater.

  7. Reliability Analysis and Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.; Christiani, E.

    1994-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified and relia......Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified...

  8. Innovative rubble mound breakwaters for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, Pasquale; Nørgaard, Jørgen Quvang Harck

    2014-01-01

    This paper intends contributing to the development of an economically and environmentally sustainable coastal infrastructure, which combines rubble mound breakwaters with Wave Energy Converters (WEC). The energy is produced by collecting wave overtopping in a front reservoir, which is returned...... experiments. The formulae are provided with the aim to be of direct use to engineers in the preliminary design of a first prototype of combined breakwater and wave energy converter....

  9. Stability Of Rubble Mound Breakwaters Using High Density Rock

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Beck, J. B.

    2000-01-01

    The present paper discusses the effect of mass density on stability of rubble mound breakwaters. A short literature review of existing knowledge is give to establish a background for the ongoing research. Furthermore, several model tests are described in which the stability of rubble mound...... breakwaters with armour stones of different densities are investigated. The results from the model test are discussed with respect to application and further research....

  10. Evaluation of Breakwaters and Sedimentation at Dana Point Harbor, CA

    Science.gov (United States)

    2011-05-01

    manmade and is protected from ocean waves by a pair of riprapped breakwaters constructed in the late 1960s. The breakwaters, consist of a long shore...Fugro West 2010). Bathymetric data were also collected in the marina basins, harbor entrance and nearshore areas outside the harbor. Two ADCPs were...tidal range (mean higher high water - mean lower low water) is 1.67 m. Wind data were available from NOAA coastal stations at Los Angeles Pier S

  11. Wave Run-Up on Rubble Breakwaters

    DEFF Research Database (Denmark)

    Van de Walle, Bjorn; De Rouck, Julien; Troch, Peter

    2005-01-01

    Seven sets of data for wave run-up on a rubble mound breakwater were combined and re-analysed, with full-scale, large-scale and small-scale model test results being taken into account. The dimensionless wave run-up value Ru-2%/Hm0 was considered, where R u-2% is the wave run-up height exceeded by 2......% of the wave run-up events and Hm0 is the significant wave height. The wave run-up data sets were compared and a clear influence of the spectral shape, characterised by the spectral width parameter epsilon, on wave run-up was noticed: high values of epsilon correspond to high values of Ru-2%/Hm0 and vice versa...... or rip-rap with a slope steeper than 1 : 2, surging waves and a JONSWAP-type wave spectrum....

  12. On the Evaluation of Failure Probability on Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, Jørgen S.; Christiani, E.

    1994-01-01

    The paper presents a level II, FORM-evaluation of the reliability against sliding of a caisson breakwater. Further, a reliability-based optimal design procedure for breakwaters exposed to multifailure mode is discussed....

  13. Adaptive neuro fuzzy inference system modeling to predict damage level of non-reshaped berm breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Mandal, S.; Rao, S.; Lokesha

    The Adaptive Neuro Fuzzy Inference System (ANFIS) model is constructed using experimental data set to predict the damage level of berm breakwater. Experimental data for non-reshaped berm breakwater are collected from Marine Structures Laboratory...

  14. A Comparison of Homogeneous and Multi-layered Berm Breakwaters with Respect to Overtopping and Stability

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Skals, Kasper; Burcharth, Hans F.

    2008-01-01

    The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm.......The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm....

  15. Ground Liquefaction and Deformation Analysis of Breakwater Structures Under Earthquakes

    Directory of Open Access Journals (Sweden)

    Zhao Jie

    2016-10-01

    Full Text Available Ground liquefaction and deformation is one of the important causes that damage engineering structures. Chinese current code for seismic design of breakwater is based on the single-level seismic design method as well as code for port and water-way engineering. However, this code can not exactly reflect the seismic performance of breakwater structures which experience different seismic intensities. In this paper, the author used a finite difference software, namely, FLAC3D, to analyze the state and compute seismic responses of breakwater structure. The breakwater foundation’s pore pressure ratio and displacement due to different earthquake have been studied. And the result show that: Smaller earthquakes have little influence on serviceability of the foundation, and severe earthquakes can liquefy some parts of the foundation; In the latter case , obvious changes of pores and foundation displaces can be found. Particularly, when seismic peak acceleration reachs 0.2g, Liquefaction appears in the foundation and mainly concentrated in the upper right side of the structure. In addition, the survey of ultra-hole pressure and displacement values of sand layers of the breakwater, manifests when the ultra pore pressure near 1.0, displacement and overturning structure is relatively large, resulting in varying degrees of damage to the structure. This paper’s research can provide theoretical and designable reference for similar engineering structures

  16. Overtopping of Berm Breakwaters Evaluation of Overtopping Formula

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2005-01-01

    The berm breakwater concept is basicly rather old, but was not used very much until it was “reinvented” in the early 1980’ties, when a slope protection for an airfield runway extending into the sea in the Alutian Islands, Alaska was designed.......The berm breakwater concept is basicly rather old, but was not used very much until it was “reinvented” in the early 1980’ties, when a slope protection for an airfield runway extending into the sea in the Alutian Islands, Alaska was designed....

  17. Scour at the head of a vertical-wall breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    1997-01-01

    This paper presents the results of an experimental investigation on the near-bed flow patterns, the bed shear stress amplification and scour around the head of a vertical-wall breakwater, using regular waves. The Keulegan-Carpenter number (KC), based on the diameter of the breakwater head, is found...... to be the major parameter that governs the flow and the equilibrium scour depth. Basic flow structures are identified as function of KC. The scour depth is found to increase with increasing the Keulegan-Carpenter number. The necessary extent of the conventional stone protection is studied. An empirical formula...

  18. Simulating the rubble mound underlying armour units protecting a breakwater

    CSIR Research Space (South Africa)

    Cooper, Antony K

    2010-01-01

    Full Text Available A variety of concrete armour units laid on top of rubble mounds are used to protect breakwaters and other harbour infrastructure. Coastal engineers build three-dimensional physical scale models to understand the dynamic processes caused by seas...

  19. Design of Vertical Wall Caisson Breakwaters using Partial Safety Factors

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    1999-01-01

    The paper presents a new system for implementation of target reliability in caisson breakwater designs by means of partial safety factors. The development of the system is explained, and tables of partial safety factors are presented for important overall stability failure modes related to caisso...

  20. Definition of Geometry for SSG Breakwater at Hanstholm Location

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    study “Definition of Geometry for SSG breakwater at Hanstholm location”, Contract Report no 89. This became necessary as requirement from the turbine people who claimed it was not feasible for a turbine to work to work with less than 1.7 m of head. Despite this had already been proven not to correspond...

  1. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2006-01-01

    The admissible overtopping discharge is a key parameter in fundamental design of breakwaters. Quite often there is a wish to limit the crest level of the structure, mainly for aesthetic reasons as a high structure might block the sea view from restaurants, promenades etc....

  2. 2-D Model Test Study of the Suape Breakwater, Brazil

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Sopavicius, A.

    This report deals with a two-dimensional model test study of the extension of the breakwater in Suape, Brazil. One cross-section was tested for stability and overtopping in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given...

  3. Probabilistic design of breakwaters in shallow hurricane-prone areas

    NARCIS (Netherlands)

    Tsimopoulou, V.; Kanning, W.; Voortman, H.G.; Verhagen, H.J.

    2011-01-01

    One of the failure mechanisms of a rubble mound breakwater is the failure of its armour layer. In order to determine the stability of an armour layer, the design load has to be defined, which is in fact the wave that attacks the structure. Being a highly stochastic phenomenon, the wave action is not

  4. Design And Construction Of Mounds For Breakwaters And Coastal Protection

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Barends, F.B.J.; Brebner, A.

    Design and construction of mound breakwaters has during the last 5 to 10 years entered a new era. The major reason for that is the realization of problems encountered as it became necessary to erect port structures on more exposed shores and in deeper waters. As a consequence of that the P.I.A.N....

  5. Generating electricity at a breakwater in a moderate wave climate

    NARCIS (Netherlands)

    Schoolderman, J.; Reedijk, B.; Vrijling, J.K.; Molenaar, W.F.; Ten Oever, E.; Zijlema, M.

    2011-01-01

    A new concept for wave energy conversion is examined as a proof of concept for generating electricity in a moderate wave climate while being integrated in a caisson breakwater. Physical model testing is performed to analyse the preliminary efficiency of the device and to identify areas of

  6. Overtopping And Rear Slope Stabillity Of Reshaping Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Lykke Andersen, Thomas

    2003-01-01

    An experimental study of overtopping and rear slope stability of reshaping breakwaters has been carried out. The variation of those two parameters with crest width, crest freeboard and sea state was investigated. The tests showed that the variation in overtopping discharge with crest freeboard...

  7. A New Formula for Front Slope Recession of Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2010-01-01

    The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter for descri......The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter...... for describing the reshaping. The formula has also been calibrated and validated against model test data from other researchers. The significance of the new design formula is that it predicts berm recession much better than the existing methods, especially in case of more stable structures....

  8. Wave loadings acting on Overtopping Breakwater for Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Nørgaard, Jørgen Harck; Contestabile, Pasquale

    2013-01-01

    Any kind of Wave Energy Converter (WEC) requires information on reliability of technology and on time required for the return of the investment (reasonable payback). The structural response is one of the most important parameters to take in to account for a consistent assessment on innovative...... distributions. Load measurements were compared with the most used prediction method for traditional breakwaters, available in the Coastal Engineering Manual (U.S. Army Corps of Engineers, 2002). These results suggest to use the experimental data as design loadings since the design criteria for the innovative...... the incoming wave to produce electricity. 2D hydraulic model tests were carried out at the Department of Civil Engineering, Aalborg University (Denmark). The analyses of hydraulic model tests have identified the main shapes assumed by wave surfaces at the breakwater and respective spatial and temporal pressure...

  9. Experimental investigation of rubble mound breakwaters for wave energy conversion

    DEFF Research Database (Denmark)

    Luppa, C.; Contestabile, P.; Cavallaro, L.

    2015-01-01

    The paper describes recent laboratory investigation on the breakwater integrated device named “OBREC” (Overtopping BReakwater for Energy Conversion). This technology recently appeared on the wave energy converter scene as an executive outcome of improving composite seawalls by including overtopping...... type wave energy converters [1]. Two complementary experimental campaigns were carried out, in 2012 and in 2014. Several geometries and wave conditions were examined. Preliminary comparison of hydraulic behaviour has been summarized, focusing on reflection analysis and overtopping flow rate....... Preliminary design formulae are presented to predict overtopping at the rear side of the structure and in to the front reservoir based on both datasets. Moreover, some important results have been presented on hydraulic behaviour of OBREC with saturated reservoir. Particularly attention is paid to wave...

  10. Wave transmission prediction of multilayer floating breakwater using neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Patil, S.G.; Hegde, A.V.

    in unison to solve a specific problem. The network learns through examples, so it requires good examples to train properly and further a trained network model can be used for prediction purpose. Proceedings of ICOE 2009 Wave transmission... prediction of multilayer floating breakwater using neural network 577 In order to allow the network to learn both non-linear and linear relationships between input nodes and output nodes, multiple-layer neural networks are often used...

  11. Horizontal Coherence of Wave Forces on Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Archetti, R.; Frigaard, Peter; Lamberti, A.

    2001-01-01

    of breaking waves for increasing wave height are estimated and compared with existing empirical formulae. The horizontal dimension of the breaker is investigated using two different methodologies: the first analyses the decreasing of the highest 1/250 force with increasing horizontal dimension of the caisson......, with special attention to the effects of wave spreading, and the second analyses the spatial correlation of impulsive force per unit length along the breakwater....

  12. Numerical test for single concrete armour layer on breakwaters

    OpenAIRE

    Anastasaki, E; Latham, J-P; Xiang, J.

    2016-01-01

    The ability of concrete armour units for breakwaters to interlock and form an integral single layer is important for withstanding severe wave conditions. In reality, displacements take place under wave loading, whether they are small and insignificant or large and representing serious structural damage. In this work, a code that combines finite- and discrete-element methods which can simulate motion and interaction among units was used to conduct a numerical investigation. Various concrete ar...

  13. Wave Reflection and Loss Characteristics of an Emerged Quarter Circle Breakwater with Varying Seaside Perforations

    Science.gov (United States)

    Binumol, S.; Rao, Subba; Hegde, Arkal Vittal

    2017-09-01

    Breakwaters are one of the most important harbour structures constructed to withstand and dissipate the dynamic energy due to the action of the waves. Due to fast growing need of the universe and advances in technology different types of breakwaters are being developed. Quarter circle breakwater is a new type of breakwater emerged from semi circular breakwater and the first model was developed in Peoples Republic of China (2006). Quarter circle breakwater with perforations posses merits of caisson as well as perforated breakwaters such as low weight, requires less materials, suited for poor soil conditions, easily transported, handled and placed at the site, aesthetically pleasing, cost effective, eco-friendly and stable. Therefore it is necessary to carry out detailed studies on hydrodynamic characteristics to investigate the suitability and applicability of various types of quarter circle breakwaters. The present study investigates the wave reflection and loss characteristics of an emerged seaside perforated quarter circle breakwater of radius 55 cm and with varying ratios of spacing to diameter of perforations, for different water depths and wave conditions. The tests were conducted in the two-dimensional monochromatic wave flume available in Marine Structures laboratory of Department of Applied Mechanics and Hydraulics of National Institute of Technology, Surathkal, Karnataka, India. The results were plotted as non-dimensional graphs and it was observed that the reflection coefficient increases with increase in wave steepness for all values of ratio of height of breakwater structure to water depth. For a constant water depth, wave reflection increases with increase in ratio of spacing to diameter of perforations. It was also found that the loss coefficient decreases with increase in wave steepness for all values of ratio of height of breakwater structure to water depth, and ratio of spacing to diameter of perforations.

  14. Damage Accumulation in Vertical Breakwaters due to Combined Impact Loading and Pulsating Wave Loads

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, Søren R. K.

    1999-01-01

    Vertical wall breakwaters used to protect for example an harbour from large waves usually consist of large concrete caissons placed on the seabed. The wave loads can be divided in two types, pulsating and impact loads. For some types of breakwaters especially the impact wave loads can be very large...

  15. Optimal inspection strategy for rubble-mound breakwaters with time-dependent reliability analysis

    NARCIS (Netherlands)

    Nguyen, D.V.; Van Gelder, P.H.A.J.M.; Verhagen, H.J.; Vrijling, J.K.

    2010-01-01

    This paper presents a comprehensive maintenance strategy with optimal inspection planning and its application to rubble mound breakwaters. In order to fulfil designated functions, a breakwater has to be inspected during its lifetime and has to be repaired if necessary. Actions of inspecting and

  16. Innovative Design for Sea Dikes and Breakwaters for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Stagonas, Dimitris; Müller, Gerald

    2012-01-01

    This paper intends contributing to an economically and environmentally sustainable development of coastal infrastructures by investigating the possibility of combining together breakwaters and Wave Energy Converters (WEC). The latter change the wave energy to electricity, which may serve both...... the rubble mound breakwaters and seawall related activity and the energy demand of small human communities....

  17. Wave loadings acting on innovative rubble mound breakwater for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Contestabile, Pasquale; Iuppa, Claudio; Lauro, Enrico Di

    2017-01-01

    Highlights •An innovative breakwater for overtopping wave energy conversion has been studied. •Physical model tests have been carried out and analysed. •Breakwater design information on loadings acting on various parts of the structure has been presented. •Design formulae and validation of some...

  18. Model Test Study of the Breakwater at the Dubai Port Terminal in Callao, Peru

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    This report deals with a two-dimensional model test study of the new breakwater for the Dubai Port terminal in Callao, Peru. Two cross-sections were tested namely the outer part of the breakwater (Section C) and a cross-section at the container terminal area (Section A). The length scale used...

  19. Investigation of Hydrodynamic Parameters and the Effects of Breakwaters During the 2011 Great East Japan Tsunami in Kamaishi Bay

    Science.gov (United States)

    Ozer Sozdinler, Ceren; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Suppasri, Anawat; Imamura, Fumihiko

    2015-12-01

    The March 2011 Great East Japan Tsunami was one of the most disastrous tsunami events on record, affecting the east coast of Japan to an extreme degree. Extensive currents combined with flow depths in inundation zones account for this devastating impact. Video footage taken by the eyewitnesses reveals the destructive effect and dragging capability of strong tsunami currents along the coast. This study provides a numerical modeling study in Kamaishi Bay, calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the Froude number Fr 2 ; and also other calculated hydrodynamic parameters, such as the distribution of instantaneous flow depths, maximum currents and water surface elevations that occurred during this catastrophic tsunami. Analyses were performed by using the tsunami numerical modeling code NAMI DANCE with nested domains at a higher resolution. The effect of the Kamaishi breakwater on the tsunami inundation distance and coastal damage was tested by using the conditions of "with breakwater," "without breakwater," and "damaged breakwater." Results show that the difference between the hydrostatic pressure on the seaward side of the breakwater and the leeward side of the breakwater is quite high, clarifying conditions contributing to failure of the breakwater. Lower water surface elevations were calculated in the case of a breakwater existing at the entrance, a partly valid condition for the damaged breakwater case. The results are different for current velocities and Fr_{max}2 in the "with breakwater" condition due to the concentration of energy through the breakwater gaps.

  20. Hydrodynamic performance of multiple-row slotted breakwaters

    Science.gov (United States)

    Elbisy, Moussa S.; Mlybari, Ehab M.; Helal, Medhat M.

    2016-06-01

    This study examines the hydrodynamic performance of multiple-row vertical slotted breakwaters. We developed a mathematical model based on an eigenfunction expansion method and a least squares technique for Stokes second-order waves. The numerical results obtained for limiting cases of double-row and triple-row walls are in good agreement with results of previous studies and experimental results. Comparisons with experimental measurements of the reflection, transmission, and dissipation coefficients ( C R , C T , and C E ) for double-row walls show that the proposed mathematical model adequately reproduces most of the important features. We found that for double-row walls, the C R increases with increasing wave number, kd, and with a decreasing permeable wall part, dm. The C T follows the opposite trend. The C E slowly increases with an increasing kd for lower kd values, reaches a maximum, and then decreases again. In addition, an increasing porosity of dm would significantly decrease the C R , while increasing the C T . At lower values of kd, a decreasing porosity increases the C E , but for high values of kd, a decreasing porosity reduces the C E . The numerical results indicate that, for triple-row walls, the effect of the arrangement of the chamber widths on hydrodynamic characteristics is not significant, except when kdrow slotted breakwaters may exhibit a good wave-absorbing performance at kd>0.5, where by the horizontal wave force may be smaller than that of a single wall. On the other hand, the difference between double-row and triple-row vertical slotted breakwaters is marginal.

  1. Numerical Modelling of Solitary Wave Experiments on Rubble Mound Breakwaters

    Science.gov (United States)

    Guler, H. G.; Arikawa, T.; Baykal, C.; Yalciner, A. C.

    2016-12-01

    Performance of a rubble mound breakwater protecting Haydarpasa Port, Turkey, has been tested under tsunami attack by physical model tests conducted at Port and Airport Research Institute (Guler et al, 2015). It is aimed to understand dynamic force of the tsunami by conducting solitary wave tests (Arikawa, 2015). In this study, the main objective is to perform numerical modelling of solitary wave tests in order to verify accuracy of the CFD model IHFOAM, developed in OpenFOAM environment (Higuera et al, 2013), by comparing results of the numerical computations with the experimental results. IHFOAM is the numerical modelling tool which is based on VARANS equations with a k-ω SST turbulence model including realistic wave generation, and active wave absorption. Experiments are performed using a Froude scale of 1/30, measuring surface elevation and flow velocity at several locations in the wave channel, and wave pressure around the crown wall of the breakwater. Solitary wave tests with wave heights of H=7.5 cm and H=10 cm are selected which represent the results of the experiments. The first test (H=7.5 cm) is the case that resulted in no damage whereas the second case (H=10 cm) resulted in total damage due to the sliding of the crown wall. After comparison of the preliminary results of numerical simulations with experimental data for both cases, it is observed that solitary wave experiments could be accurately modeled using IHFOAM focusing water surface elevations, flow velocities, and wave pressures on the crown wall of the breakwater (Figure, result of sim. at t=29.6 sec). ACKNOWLEDGEMENTSThe authors acknowledge developers of IHFOAM, further extend their acknowledgements for the partial supports from the research projects MarDiM, ASTARTE, RAPSODI, and TUBITAK 213M534. REFERENCESArikawa (2015) "Consideration of Characteristics of Pressure on Seawall by Solitary Waves Based on Hydraulic Experiments", Jour. of Japan. Soc. of Civ. Eng. Ser. B2 (Coast. Eng.), Vol 71, p I

  2. Overtopping of Rubble Mound Breakwaters with Front Reservoir

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke

    2007-01-01

    The design and performance of breakwaters with front reservoir are discussed on the basis of physical 2-D model tests with a number of cross sections, in which vertopping discharge and spatial distribution, wave forces on inner parapet walls, and stability of reservoir armour were studied....... The sensitivity of these quantities to the width of the reservoir is discussed. It is demonstrated that front reservoir solutions are more economical than conventional cross section solutions, such as bermed structures and mild slope structures, in cases where low crests and small overtopping discharges...

  3. Parameter optimization using GA in SVM to predict damage level of non-reshaped berm breakwater.

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Lokesha.; Mandal, S.; Rao, S.; Patil, S.G.

    In the present study, Support Vector Machines (SVM) and hybrid of Genetic Algorithm (GA) with SVM models are developed to predict the damage level of non-reshaped berm breakwaters. Optimal kernel parameters of SVM are determined by using GA...

  4. Fiducial-based monocular 3D displacement measurement of breakwater armour unit models.

    CSIR Research Space (South Africa)

    Vieira, R

    2008-11-01

    Full Text Available This paper presents a fiducial-based approach to monitoring the movement of breakwater armour units in a model hall environment. Target symbols with known dimensions are attached to the physical models, allowing the recovery of three...

  5. Flow under standing waves Part 2. Scour and deposition in front of breakwaters

    DEFF Research Database (Denmark)

    Gislason, Kjartan; Fredsøe, Jørgen; Sumer, B. Mutlu

    2009-01-01

    and routines for, updating the computational mesh based on the mass balance of sediment. Laboratory experiments of scour also were conducted in a wave flume to obtain data for model verification. Both in the numerical simulations and in the laboratory experiment, two kinds of breakwaters were used: A vertical-wall...... breakwater; and a sloping-wall breakwater (Slope: 1:1.5). Numerically obtained scour-deposition profiles were compared with the experiments. The numerical results show that the equilibrium scour depth normalized by the wave height decreases with increasing water-depth-to-wave-length ratio. Although...... the numerical results obtained for vertical-wall breakwaters are consistent with the existing experimental data (including the present experiment), the numerical results for the sloping-wall case appear to be not very satisfactory....

  6. Overtopping of Berm Breakwaters Extension of Overtopping Formula

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, H. F.

    2005-01-01

    In this paper is presented an improved version of the overtopping formula by Lykke Andersen & Burcharth (2004)valid for berm breakwaters with initial slopes of 1:1.25. In the present paper guidelines is given on how to modify the formula to take into account the initial slope angle. Further...... the formula is improved so it gives reliable estimates also for more stable structures. The extension of the overtopping formula is based on analysis of front slope stability data from many different data sets. In most cases there is only a small difference between the Lykke Andersen & Burcharth (2004......) formula and the present improved formula. However, for a more stable structure and low wave steepness the improved formula performs better. Six different data sets are used to study the validity of the Lykke Andersen & Burcharth (2004) formula, the present improved formula and the CLASH neural network...

  7. Armor stability of hardly (or partly) reshaping berm breakwaters

    DEFF Research Database (Denmark)

    Moghim, M. N.; Andersen, Thomas Lykke

    2015-01-01

    of the simple method based on measured data of Rec and hf is better than the presented stability equation based on wave momentum flux parameter. When using the best prediction formulae for recession and depth of intersection the simple method and the momentum flux stability equation provide similar uncertainty.......This paper deals with stability of hardly (or partly) reshaping berm breakwaters. A simple physical argument is used to derive a new stability formula based on the assumption that the maximum wave force causing damage of armor layer is proportional to the maximum wave momentum flux near...... momentum flux approach the damage to the front slope (eroded area) can be very well predicted. Moreover, a simple method to estimate the eroded area based on measured or calculated berm recession (Rec) and depth of intersection of reshaped and initial profile (hf) is presented. The performance...

  8. Numerical investigation of floating breakwater movement using SPH method

    Directory of Open Access Journals (Sweden)

    A. Najafi-Jilani

    2011-06-01

    Full Text Available In this work, the movement pattern of a floating breakwater is numerically analyzed using Smoothed Particle Hydrodynamic (SPH method as a Lagrangian scheme. At the seaside, the regular incident waves with varying height and period were considered as the dynamic free surface boundary conditions. The smooth and impermeable beach slope was defined as the bottom boundary condition. The effects of various boundary conditions such as incident wave characteristics, beach slope, and water depth on the movement of the floating body were studied. The numerical results are in good agreement with the available experimental data in the literature The results of the movement of the floating body were used to determine the transmitted wave height at the corresponding boundary conditions

  9. Effect of Short-Crestedness and Obliquity on Non-Breaking and Breaking Wave Forces Applied to Vertical Caisson Breakwaters

    DEFF Research Database (Denmark)

    Martinelli, Luca; Lamberti, Alberto; Frigaard, Peter

    2007-01-01

    This paper addresses wave forces applied to vertical caisson breakwaters. Design diagrams are proposed to evaluate the reduction of the breaker wave force with increasing horizontal length of the units. A model in 1:100 scale of a typical Italian vertical breakwater was tested under multidirectio......This paper addresses wave forces applied to vertical caisson breakwaters. Design diagrams are proposed to evaluate the reduction of the breaker wave force with increasing horizontal length of the units. A model in 1:100 scale of a typical Italian vertical breakwater was tested under...

  10. A SYSTEM TO MAKE USE OF EXISTING BREAKWATERS AS OVERTOPPING WAVE ENERGY CONVERTERS

    Directory of Open Access Journals (Sweden)

    DENIZ ÜNSALAN

    2016-06-01

    Full Text Available The main purpose of building breakwaters is to produce safe havens for ships and boats in rough seas. The general architecture for a breakwater is a wall with a trapezoidal -shaped cross section extending parallel to the shoreline. As the waves from the open sea approach, they are encountered by the so- called slope and revetment of the breakwater, where the wave is broken and its energy is dissipated and/or reflected back. However, the ever -increasing attractiveness of the utilization of waves as energy sources, paralleling to the increasing monetary and envir onmental costs of energy, has led the authors to consider the vast amounts of this otherwise dissipated energy into useful electrical energy. A wave energy conversion concept, which can be classified as an “overtopping” wave energy converter was conceived, where the open sea-facing (revetment side of the breakwater is fitted by a water collecting channel at a suitable height above the calm water level, running alongside the breakwater. The channel leads the collected water to a powerhouse containing a low head turbine (or a set of such turbines discharging it to the calm water of the inner harbour. Power obtained from these turbines can be converted to electrical energy. In this study, an estimation of the volume of water collected by the channel and the energy production for a proposed breakwater - power station system for a typical rough weather shall be made. It is deemed that the feasibility of this system is comparable to and even higher than the other wave energy conversion systems since it does not require additional facilities and power supply lines to be built due to its proximity to the existing energy transmission lines, except for the addition of new features/installations to the existing breakwaters.

  11. Oyster reefs as natural breakwaters mitigate shoreline loss and facilitate fisheries.

    Directory of Open Access Journals (Sweden)

    Steven B Scyphers

    Full Text Available Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards "living shoreline" approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m(-2 at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus were the most clearly enhanced (+297% by the presence of breakwater reefs, while red drum (Sciaenops ocellatus (+108%, spotted seatrout (Cynoscion nebulosus (+88% and flounder (Paralichthys sp. (+79% also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study

  12. Investigation of structural responses of breakwaters for green water based on fluid-structure interaction analysis

    Directory of Open Access Journals (Sweden)

    Chi-Seung Lee

    2012-06-01

    Full Text Available In the present study, the structural response of breakwaters installed on container carriers against green water impact loads was numerically investigated on the basis of the fluid-structure interaction analysis. A series of numerical studies is carried out to induce breakwater collapse under such conditions, whereby a widely accepted fluid-structure interaction analysis technique is adopted to realistically consider the phenomenon of green water impact loads. In addition, the structural behaviour of these breakwaters under green water impact loads is investigated simultaneously throughout the transient analysis. A verification study of the numerical results is performed using data from actual collapse incidents of breakwaters on container carriers. On the basis of the results of a series of numerical analyses, the pressure distribution of green water was accurately predicted with respect to wave mass and velocity. It is expected that the proposed analytical methodology and predicted pressure distribution could be used as a practical guideline for the design of breakwaters on container carriers.

  13. Comparison of Homogenous and Multi-layered Berm Breakwaters with Respect to Overtopping and Front Slope Stability

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.

    2009-01-01

    A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...

  14. Report on 3D-model Testing of the Breakwater for a new Port at Puerto de la Cruz, Tenerife

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Meinert, Palle; Andersen, Thomas Lykke

    The report contains a 3-dimensional model test study of the round head and outer part of the breakwater for the new port at Puerto de la Cruz, Tenerife.......The report contains a 3-dimensional model test study of the round head and outer part of the breakwater for the new port at Puerto de la Cruz, Tenerife....

  15. Partial Coefficient System for the Design of Monolithic Vertical Breakwaters Considering Sliding and Rupture Failure of the Foundation

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Christiani, Erik; Sørensen, John Dalsgaard

    1995-01-01

    The main object is to present a set of calibrated partial coefficients for monolithic vertical breakwater failure modes. A preliminary design of the monolithic breakwater will be considered, which will be designed from existing partial coefficients, documented in Eurocode 7 (1994). From this desi...

  16. Experimental Study and Numerical Modeling of Wave Induced Pore Pressure Attenuation Inside a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Troch, Peter; Rouck, Julien De; Burcharth, Hans Falk

    2003-01-01

    attenuation is studied using experimental data (in Section 2) and using a numerical wave flume (in Section 3). The experimental study includes the analysis of large scale data from a physical breakwater model and prototype data from the Zeebrugge breakwater. The large scale data are taken from literature...... and have been re-analysed in detail with respect to the attenuation characteristics. The analysis follows the method by Burcharth et al. (1999) and confirms the practical calculation method for the attenuation of the pore pressure in the core given in this reference. The attenuation of pore pressures...... in a breakwater core is also studied in the numerical wave flume VOFbreak. The numerical results are compared to the results from the experimental study....

  17. Damage level prediction of non-reshaped berm breakwater using ANN, SVM and ANFIS models

    Directory of Open Access Journals (Sweden)

    Sukomal Mandal

    2012-06-01

    Full Text Available The damage analysis of coastal structure is very important as it involves many design parameters to be considered for the better and safe design of structure. In the present study experimental data for non-reshaped berm breakwater are collected from Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, NITK, Surathkal, India. Soft computing techniques like Artificial Neural Network (ANN, Support Vector Machine (SVM and Adaptive Neuro Fuzzy Inference system (ANFIS models are constructed using experimental data sets to predict the damage level of non-reshaped berm breakwater. The experimental data are used to train ANN, SVM and ANFIS models and results are determined in terms of statistical measures like mean square error, root mean square error, correlation coefficient and scatter index. The result shows that soft computing techniques i.e., ANN, SVM and ANFIS can be efficient tools in predicting damage levels of non reshaped berm breakwater.

  18. Design Formulae for Hydraulic Stability and Structural Integrity of Dolos Breakwater Round-Heads

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Jensen, Jacob Birk; Liu, Z.

    1995-01-01

    A rational design of Dolos armour unit should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) resulted in design formulae for the trunk of a 1:1.5 slope Dolos breakwater without superstructure including both the hydrau......A rational design of Dolos armour unit should incorporate both the hydraulic stability and the structural integrity. The previous tests performed by Aalborg University (AU) resulted in design formulae for the trunk of a 1:1.5 slope Dolos breakwater without superstructure including both...

  19. Validity of simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    2011-01-01

    Wave slamming on vertical breakwaters cause a sudden, impulsive load that may cause a caisson to slide on its foundation. Alternatively, geotechnical failure may occur in the subsoil. This paper investigates whether simple analytical solutions, accounting only for the sliding along the caisson–foundation...... interface, can be utilized to properly determine the deformations of the breakwater. Comparisons are made with results obtained by numerical models that include the material response of the soil. Firstly, a computational model is suggested that assumes a fully drained behavior of the subsoil. Secondly...

  20. Innovative Seawalls and Rubble Mound Breakwater Design for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, P.; Ferrante, V.

    2012-01-01

    The development of contemporary coastal infrastructure is nowadays dictated by the need for economical and environmental sustainability, which can however be provided by the combination of breakwaters and Wave Energy Converters (WEC). The latter convert wave energy to electricity, whilst previous...... research has shown that they can also enhance the protective roll of coastal structures such as rubble mound breakwaters and vertical seawalls. Such WECs can in theory provide sufficient energy to partly cover the needs of small communities and although retrofitting solutions for vertical seawalls have...... that such a structure will convert wave energy to electricity and in the same time it will reduce run-up and overtopping....

  1. Stability of Low-Crested Breakwaters in Shallow Water Short Crested Waves

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Burcharth, Hans Falk

    2003-01-01

    The paper presents results of 3D laboratory experiments on low-crested breakwaters. Two typical structural layouts were tested at model scale in a wave basin at Aalborg University, Denmark, to identify and quantify the influence of various hydrodynamic conditions (obliquity of short crested waves......, wave hight and wave steepness) and structural geometries (crest width and freeboard) on the stability of low-crested breakwaters. Results are given in terms of recommendations for design guidelines for structure stability. Damage parameters for the trunk and the roundhead are proposed based on analysis...

  2. Analytical Study on an Oscillating Buoy Wave Energy Converter Integrated into a Fixed Box-Type Breakwater

    Directory of Open Access Journals (Sweden)

    Xuanlie Zhao

    2017-01-01

    Full Text Available An oscillating buoy wave energy converter (WEC integrated to an existing box-type breakwater is introduced in this study. The buoy is installed on the existing breakwater and designed to be much smaller than the breakwater in scale, aiming to reduce the construction cost of the WEC. The oscillating buoy works as a heave-type WEC in front of the breakwater towards the incident waves. A power take-off (PTO system is installed on the topside of the breakwater to harvest the kinetic energy (in heave mode of the floating buoy. The hydrodynamic performance of this system is studied analytically based on linear potential-flow theory. Effects of the geometrical parameters on the reflection and transmission coefficients and the capture width ratio (CWR of the system are investigated. Results show that the maximum efficiency of the energy extraction can reach 80% or even higher. Compared with the isolated box-type breakwater, the reflection coefficient can be effectively decreased by using this oscillating buoy WEC, with unchanged transmission coefficient. Thus, the possibility of capturing the wave energy with the oscillating buoy WEC integrated into breakwaters is shown.

  3. Optimal inspection planning with time-dependent reliability analysis, application to rubble-mound breakwaters

    NARCIS (Netherlands)

    Nguyen, D.V.; Van Gelder, P.H.A.J.M.; Verhagen, H.J.; Vrijling, J.K.

    2010-01-01

    In order to avoid failure in its lifetime, a breakwater system has to be inspected and, if necessary, has to be repaired. In this paper, a comprehensive maintenance strategy with optimal inspection planning is formulated. Rational maintenance decision-making approaches are discussed. The proposed

  4. Analyses of Stability of Caisson Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Lars; Andersen, Thomas Lykke

    2009-01-01

    The paper deals with the analysis of the overall stability of caisson breakwaters exposed to impulsive wave loadings, in particular regarding sliding failure and failure in the subsoil. A comparison is made between prediction of sliding distances by a simple onedimensional (1-D) dynamic analysis ...

  5. Rationalization of safety factors for breakwater design in hurricane-prone areas

    NARCIS (Netherlands)

    Tsimopoulou, V.; Kanning, W.; Verhagen, H.J.; Vrijling, J.K.

    2011-01-01

    This paper presents the development of a semi-probabilistic method for armour layer design of rubble mound breakwaters, which is based on the use of safety factors. The objective is to introduce an approach that is both attractive to designers and sufficiently reliable when a high degree of

  6. Final Report for Full-Scale Load Monitoring of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Frigaard, Peter; Helm-Petersen, Jacob

    As associated partner, Aalborg University (AU) has participated in different aspects of "the Zeebrugge project" . At an early stage AU has developed and tested an algorithm aiming at deducing incident waves at the prototype breakwater by reflection analysis. Secondly AU, has been engaged with the...

  7. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2006-01-01

     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  8. Effect of hydraulic and structural parameters on the wave run-up over the berm breakwaters

    Directory of Open Access Journals (Sweden)

    Farzad Milanian

    2017-05-01

    Full Text Available The main aim of this study is to investigate the effect of berm breakwater on wave run-up. A total of 200 numerical analysis tests have been carried out in this paper to investigate the effect of berm width, wave height, and wave period on the wave run-up, using an integrating technique of Computer-Aided Design (CAD and Computational Fluid Dynamics (CFD. Direct application of Navier Stokes equations within the berm width has been used to provide a more reliable approach for studying the wave run-up over berm breakwaters. A well tested Reynolds-averaged Navier–Stokes (RANS code with the Volume of Fluid (VOF scheme was adopted for numerical computations. The computational results were compared with theoretical data to validate the model outputs. Numerical results showed that the simulation method can provide accurate estimations for wave run-up over berm breakwaters. It was found that the wave run-up may be decreased by increasing the berm width up to about 36 percent. Furthermore, the wave run-up may increase by increasing the wave height and wave period up to about 53 and 36 percent, respectively. These results may convince the engineers to use this model for design of berm breakwater in actual scale by calculating the Reynolds numbers.

  9. 2-D Model Test Study of the Breakwater at Porto de Dande , Angola

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Ramirez, Jorge Robert Rodriguez; Burcharth, Hans F.

    This report deals with a two-dimensional model test study of the new breakwater at Porto de Dande, Angola. One cross-section was tested for stability and overtopping in various sea conditions. The length scale used for the model tests was 1:32. Unless otherwise specified all values given in this ...

  10. Riprap stability on the inner slopes of medium-height breakwaters

    NARCIS (Netherlands)

    Verhagen, H.J.; Van Dijk, B.; Nederpel, A.

    2003-01-01

    Medium height breakwaters are subjected to a considerable amount of overtopping. This implies the armour on the inner slope has to stable against overtopping waves. Existing equations do lack some basic understanding of the process of starting up movement of rock on the inner slopes. In case one

  11. Riprap stability on the inner slopes of medium-height breakwaters

    NARCIS (Netherlands)

    Verhagen, H.J.; Van Dijk, B.; Nederpel, A.

    2003-01-01

    Medium height breakwaters are subjected to a considerable amount of overtopping. This implies the armour on the inner slope has to stable against overtopping waves. Existing equations do lack some basic understanding of the process of starting up movement of rock on the inner slopes. In order to get

  12. Verification of Overall Safety Factors In Deterministic Design Of Model Tested Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2001-01-01

    The paper deals with concepts of safety implementation in design. An overall safety factor concept is evaluated on the basis of a reliability analysis of a model tested rubble mound breakwater with monolithic super structure. Also discussed are design load identification and failure mode limit st...

  13. Three-Dimensional Model Test Study of Xbloc Armoured Breakwaters at Punta Catalina, Dominican Republic

    DEFF Research Database (Denmark)

    Røge, Mads Sønderstrup; Andersen, Thomas Lykke

    The present report presents results from a three-dimensional model test study carried out at Aalborg University in the period June 2015 – August 2015. The objectives of the model tests were to study the stability of the Xbloc armoured breakwaters at Punta Catalina under short-crested wave attack...

  14. Application of Reliability Analysis for Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard; Christiani, E.

    1995-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of some of the most important failure modes are described. The failures are sliding and slip surface failure of a rubble mound and a clay foundation. Relevant design vari...

  15. Wave Loads on Rubble Mound Breakwater Crown Walls in Long Waves

    DEFF Research Database (Denmark)

    Røge, Mads Sønderstrup; Færch Christensen, Nicole; Thomsen, Jonas Bjerg

    2014-01-01

    This paper evaluates the formulae by Nørgaard et al. (2013) for predicting wave loads on rubble mound breakwater crown walls on new model tests. The formulae are tested outside their validation area by means of waves with a low wave steepness and low run-up height compared to the armour freeboard...

  16. Three-Dimensional Model Test Study of Modified Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    caisson breakwater at Port of Castellon, Spain, tested earlier (Nørgaard & Lykke Andersen, 2013). Associate Prof. Thomas Lykke Andersen and M.Sc. Jørgen Quvang Harck Nørgaard were in charge of the model tests. Engineer assistant Niels Drustrup assisted in the laboratory with the construction...

  17. Wave Transformation and Attenuation near the Submerged Breakwater and Vegetation: Field investigation and Numerical simulation

    Science.gov (United States)

    Shin, S.; Kim, I.; Hur, D.; Lee, W.; Kim, J.; Lee, J. L.; Lee, H. S.; Kim, H. G.

    2016-12-01

    The large scale decreasing of beach width in the Anmok beach had occurred due to the coastal erosion caused by the short-term events, such as unexpected high waves and storms. Hence, the city officials decided the installation of hard construction, and the first submerged breakwater, which is a structure that parallels the beach and support as a wave absorber, was constructed on this beach in September 2014. In order to deduce the correlation equation of the transmitted wave heights (TWH) after the breakwater installed, we have observed the transmitted wave height at four sites nearby the breakwater, two wave gauges were mounted on the front side of the breakwater, and the others were placed in the behind side of it. We found that the TWH using the formula suggested by Takayama et al. (1985) for the submerged breakwaters (crown elevation: D.L. (-)0.5 m, crown width: 18.5 m, bottom width: 22.8 m) was 0.501, whereas the value which was measured by the wave gauge showed 0.547. Therefore, we suggested a formula for estimating the TWH based on the field observation data. 3D numerical model (LES-WASS-3D) was employed to estimate hydrodynamic chracteristics near the submerged breakwater. The results showed that the predicted TWH agreed well with the field field observation data results. In order to consider evironmet-friendly measure, the model also simulated the wave transformation and attenuation phenomina near the area of submerged vegetation. The model was already verified in two-dimensional laboratory experiments. In this study, the numerical model is used to predict the three-dimensional wave transformation and attenucation through the underwater vegetation. The results are compared with those in the case of submerged breakwater. This research was partially supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1A2B4015419) and Korean Institute of Marine Science and Technology

  18. Particle swarm optimization based support vector machine for damage level prediction of non-reshaped berm breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Harish, N.; Mandal, S.; Rao, S.; Patil, S.G.

    breakwater. Soft computing tools like Artificial Neural Network, Fuzzy Logic, Support Vector Machine (SVM), etc, are successfully used to solve complex problems. In the present study, SVM and hybrid of Particle Swarm Optimization (PSO) with SVM (PSO...

  19. Investigation on bragg reflection of surface water waves induced by a train of fixed floating pontoon breakwaters

    Directory of Open Access Journals (Sweden)

    Huei-Tau Ouyang

    2015-11-01

    Full Text Available The water wave characteristics of Bragg reflections from a train of fixed floating pontoon breakwaters was studied numerically. A numerical model of boundary discretization type was developed to calculate the wave field. The model was verified by comparing to analytical data in literature and good agreements were achieved. Series of parametric studies were conducted systematically to investigate the dependence of the reflected coefficients by the Bragg scattering on the design variables, including the spacing between the breakwaters, the total number of installed breakwaters, the draft and width do the breakwater, and wave length. Certain wave characteristics of the Bragg reflections were observed and discussed in details which might be of help for practical engineering applications in shoreline protection from incident waves.

  20. Application of a Spectral Wave Model to Assess Breakwater Configurations at a Small Craft Harbour on Lake Ontario

    Directory of Open Access Journals (Sweden)

    Amelia H. Cooper

    2016-08-01

    Full Text Available A surface wave model using three nested grids is applied to the eastern end of Lake Ontario to investigate wave propagation from an open lake environment to a small craft harbour protected by a breakwater. The Simulating WAves Nearshore (SWAN spectral wave model, coupled with the Delft3D hydrodynamic model, is applied to simulate a series of storms in November, 2013. The model results are compared to observations from two pressure sensors, and used to quantify wave properties around existing and future breakwaters to evaluate the bulk changes to the harbour configuration. Overall, the results indicate that the rubblemound breakwater reduces wave heights in the existing harbour by 63% compared to no breakwater, and that the addition of a surface breakwater extension could reduce wave heights by an additional 54%. Wave height attenuation was found to be highly dependent on the incident wave direction relative to breakwater orientation. The spectral wave model is useful for simulating wave transformation for broad directional spectra in wind-sea conditions over large scales to semi-protected areas such as small craft harbours.

  1. Transmission coefficients of a floating rectangular breakwater with porous side plates

    Directory of Open Access Journals (Sweden)

    Il-Hyoung Cho

    2016-01-01

    Full Text Available The interaction between incident waves and a floating rectangular breakwater with the vertical porous side plates has been investigated in the context of the two-dimensional linear potential theory. The matched eigenfunction expansion method(MEEM for multiple domains is applied to obtain the analytic solutions. The dependence of the transmitted coefficients and motion responses on the design parameters, such as porosity and protruding depth of side plates, is systematically analyzed. It is found that the non-dimensional wavelength where the sudden drop of transmission coefficients occurs, corresponds to the heave resonant frequency obtained from Ruol et al. (2013 for π-type floating breakwater. It is concluded that both properly selected porosity and deeper protruding depth of side plates are helpful in reducing the transmission coefficients and also extending the wider applicable extent of incident wavelength for performance enhancement.

  2. Prototype Scale Mooring Load and Transmission Tests for a Floating Tire Breakwater.

    Science.gov (United States)

    1978-04-01

    2 J¶ TESTS FOR A FLOA flNG lIRE BREAKWATER ~~~ 6. P TW RG. REPORT UMBER 7. AUTHOR(. __________ ~ . cONTRA cT OR GR~~~T~~ y MB~~R~~ Michael L...ij~ ct ~ent..wave height/wavelength H~ t ransmit ted w ave hei ght (centimeters~ K t ransmiss ion coe f f i c i e n t ; F{~ / fL,’ L incident...F loa t ing breakwaters pre vent wave energy transmission by r e f l ec t ion and by dissi pat i on p r imar i ly through the generation of tur

  3. Parameters Influencing Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Walle, Björn Van de; Rouck, Julien De; Damme, Luc Van

    2002-01-01

    Full scale wave run-up measurements have been performed on the Zebrugge rubble mound breakwater. Wave run-up also has been investigated on various small scale models of the Zeebrugge breakwater. A significant difference between the results has been noticed. Additional small scale model testing has...... been carried out on a slightly modified scale model: a regular armour unit pattern has been applied in stead of an irregular pattern as in full scale. The aim of the additional laboratory tests was to investigate the influence of the spectral width parameter and the influence of the position...... of the wave run-up step gauge with respect to the armour unit pattern and the water level....

  4. Validity of Simplified Analysis of Stability of Caison Breakwaters on Rubble Foundation Exposed to Impulsive Loads

    DEFF Research Database (Denmark)

    Andersen, Lars; Burcharth, Hans F.; Andersen, Thomas Lykke

    Excessive sliding and foundation failures are common failure modes for caisson breakwaters on rubble foundations. An accurate evaluation of these failure modes demands a dynamic analysis in the time domain, and due to the complexity of the material response, numerical solution methods must...... be applied. The waveload time series as well as elastic-plastic modelling of the seabed soil, the rubble foundation and the caisson are needed as input for such an exercise....

  5. Wave Loading and Overtopping on Caisson Breakwaters in Multidirectional Breaking Seas

    DEFF Research Database (Denmark)

    Grønbech, J.; Hald, Tue; Frigaard, Peter

    1997-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as a part of the framework programme "Dynamics of Structures" financially supported by the Danish...... Technical Research Council, during the period of January 97 to July 97. The tests were carried out in 3D wave basin at the Hydraulics and Coastal Engineering Laboratory, Aalborg University....

  6. Wave Loading and Overtopping on Vertical Wall Breakwaters in Multidirectional Breaking Seas

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Grønbech, J.; Hald, Tue

    1998-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamics of Structures" financially supported by the Danish...... Technical Research Council, during the period of January 97 to December 97. The test were carried out in the 3D wave basin at the Hydraulics and Coastal Engineering Laboratory, Aalborg University....

  7. Peak mooring forces in the horizontal interlaced multi-layered moored floating pipe breakwater

    Directory of Open Access Journals (Sweden)

    Vishwanath Mane

    2011-06-01

    Full Text Available Present study aims to investigate the influence of relative breakwater width W/L (W=width of breakwater, L=wavelength, wave steepness Hi/gT2 (Hi=incident wave height, T=wave period and relative wave height d/W (d=water depth on forces in the moorings of horizontal interlaced multi-layered moored floating pipe breakwater (HIMMFPB model. Studies were conducted on scaled down physical models having three layers of Poly Vinyl Chloride (PVC pipes, wave steepness Hi/gT2 varying from 0.063 to 0.849, relative width W/L varying from 0.4 to 2.65 and relative spacing S/D=2 (S=horizontal centre-to-centre spacing of pipes, D=diameter of pipes. Peak mooring forces were also measured and data collected is analyzed by plotting non-dimensional graphs depicting variation of fs/γW2 (fs=Sea side Mooring force, γ=specific weight of water & fl/γW2 (fl=Lee side Mooring force with Hi/gT2 for d/W varying from 0.082 to 0.276 and also variation of fs/γW2 and fl/γW2 with W/L for Hi/d varying from 0.06 to 0.400.

  8. Economic Assessment of Overtopping BReakwater for Energy Conversion (OBREC: A Case Study in Western Australia

    Directory of Open Access Journals (Sweden)

    Pasquale Contestabile

    2016-12-01

    Full Text Available This paper constructs an optimal configuration assessment, in terms of the financial returns, of the Overtopping BReakwater for wave Energy Conversion (OBREC. This technology represents a hybrid wave energy harvester, totally embedded in traditional rubble mound breakwaters. Nine case studies along the southern coast of Western Australia have been analysed. The technique provides tips on how to estimate the quality of the investments, for benchmarking with different turbine strategy layouts and overlapping with the costs of traditional rubble mound breakwaters. Analyses of the offshore and nearshore wave climate have been studied by a high resolution coastal propagation model, forced with wave data from the European Centre for Medium-Range Weather Forecasts (ECMWF. Inshore wave conditions have been used to quantify the exploitable resources. It has been demonstrated that the optimal investment strategy is nonlinearly dependent on potential electricity production due to outer technical constraints. The work emphasizes the importance of integrating energy production predictions in an economic decision framework for prioritizing adaptation investments.

  9. Wave transmission over permeable submerged breakwaters; Transmision del oleaje en rompeolas sumergidos permeables

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-y-Zurvia-Flores, Jaime Roberto; Fragoso-Sandoval, Lucio [Instituto Politecnico Nacional(Mexico)

    2008-10-15

    The permeable submerged breakwaters represent a coastal protection alternative, where some degree of wave energy transmission is acceptable. Such would be the case of tourist beach protection in Mexico. In previous researches, like those performed by D'Angremond et al. (1996), Seabrook and Hall (1998), and Briganti et al. (2003), the empirical formulas developed, give only some limited information over the spatial distribution of wave energy over the structure. Therefore, a decision was made to conduct a study on a reduced physical model of a permeable submerged breakwater based on the results presented by those researchers and with possible applications. Therefore this paper presents the development of a study of wave transmission over permeable submerged breakwaters performed in a reduced physical model of different sections of a submerged rockfill breakwater of the trapezoidal type. This was done in a narrow wave flume with a hydraulic irregular wave generator controlled by a computer that was used to generate and to reproduce different types of irregular waves to be used in the tests. It also has a wave meter with four sensors, and they are connected to a computer in order to process the wave data. The main objective of the study was to determine in an experimental way the influence of the several parameters of submerged breakwater over the wave transmission coefficient. Our experimental results were comparable to those obtained by D'Angremond et al. (1996) and Seabrook and Hall (1998). The results show that the sumerged breakwater parameters of most influence over the wave transmission coefficient were relative submergence and the relative width crest of the sumerged breakwater, and that the formula by Seabrook and Hall correlates best with our results. [Spanish] Los rompeolas sumergidos permeables representan actualmente una alternativa de proteccion de costas, donde un cierto grado de transmision de energia del oleaje es aceptable, como seria el

  10. Estimation of Partial Safety Factors and Target Failure Probability Based on Cost Optimization of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Kim, Seung-Woo; Suh, Kyung-Duck; Burcharth, Hans F.

    2010-01-01

    The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors...... were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years...... in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state...

  11. Numerical study of breakwater failure due to tsunami-like undular bore impacts: The case of the port of Soma.

    Science.gov (United States)

    Martin-Medina, Manuel; Morichon, Denis; Abadie, Stephane; Le Roy, Sylvestre; Lemoine, Anne

    2017-04-01

    The Tohoku tsunami, that impacted the Japanese coast in 2011, caused great damages on many offshore vertical breakwaters ranging from the erosion of the rubble mound to the partial displacement or total collapse of caissons. The breakwater failure mechanisms were function of the tsunami wave types that vary along the Japanese coast according to the bathymetry features. The Iwate coast, characterized by deep water depths and steep slopes, was mainly impacted by tsunami overflow leading in particular to the failure of the world's deepest breakwater of Kamaishi. In the shallow waters of the Sendai bay, observations showed that breakwaters protecting harbor entrances were impacted by short waves train resembling to undular bore. This work aims to investigate this latter type of tsunami wave impacts that are less reported in the literature. We chose to focus on the highly damaged offshore breakwater of Soma, located in the south part of the Sendai bay. The hydrodynamics conditions during the tsunami impact are investigated using the VARANS Thetis code (Desombre et al., 2012), which allows to simulate both the free surface flow and the flow inside the rubble mound simulated by a porous medium. The model is forced at the offshore boundaries by the Funwave Boussinesq code that describes the transformation of the tsunami waves from the source to the generation of undular bores in shallow waters. The study includes the computation of forces acting on the caissons. We discuss the relevance of describing the hydrodynamics at the short wave scale to assess breakwater stability in the course of tsunami-like undular bore impact. References Desombre, J., Morichon, D., & Mory, M. (2012). SIMULTANEOUS SURFACE AND SUBSURFACE AIR AND WATER FLOWS MODELLING IN THE SWASH ZONE. Coastal Engineering Proceedings, 1(33), 56.

  12. Geometry Optimization of an Overtopping Wave Energy Device Implemented into the New Breakwater of the Hanstholm Port Expansion

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Stratigaki, Vasiliki; Troch, Peter

    2012-01-01

    The study presented here describes the geometry optimization of the Sea wave Slot cone Generator (SSG) overtopping wave energy converter as part of the feasibility study for the implementation of the device in the development plan of Hanstholm harbour in Denmark. The total length of the new planned...... breakwater is 1.5 km and the water depth ranges approximately from 8.0 m up to 14 m with localized influences on the wave climate. The study is conducted numerically in order to present the expected power production and overall performance of the SSG breakwater in Hanstholm. The price par kWh is also...

  13. Two-Dimensional Model Test Study of New Western Breakwater Proposal for Port of Hanstholm

    DEFF Research Database (Denmark)

    Eldrup, Mads Røge; Andersen, Thomas Lykke

    The present report presents results from a two-dimensional model test study carried out at Aalborg University in December 2016 with the proposed trunk section for the new western breakwater in Port of Hanstholm. The objectives of the model tests were to study the stability of the armour layer, to...... erosion, overtopping and transmission. The scale used for the model tests was 1:61.5. Unless otherwise specified all values given in this report are prototype values converted from the model to prototype according to the Froude model law....

  14. Hydraulic Response of Caisson Breakwaters in Multidirectional Breaking and Non-Breaking Waves

    DEFF Research Database (Denmark)

    Grønbech, J.; Kofoed, Jens Peter; Hald, Tue

    1998-01-01

    The present paper concerns the results and findings of a physical study on wave impacts on vertical caisson breakwaters situated in irregular, multidirectional breaking seas. The study has taken place as part of the framework programme "Dynamic of Structures" financially supported by the Danish...... Technical Research Council, during the period of January '97 to December '97. The tests were carried out in the 3D wave basin at the Hydraulics and Coastal Engineering Laboratory, Aalborg University. The objective of the study was to asses the effects of wave obliquity and multidirectionality on the wave...

  15. Damage pattern and damage progression on breakwater roundheads under multidirectional waves

    DEFF Research Database (Denmark)

    Comola, F.; Andersen, Thomas Lykke; Martinelli, L.

    2014-01-01

    An experimental model test study is carried out to investigate damage pattern and progression on a rock armoured breakwater roundhead subjected to multidirectional waves. Concerning damage pattern, the most critical sector is observed to shift leeward with increasing wave period. Taking angles...... over the roundhead is developed. Thus the formula also considers the shifting of the critical sector due to increasing wave period which existing formulae do not include. Finally, analysing the damage produced by double peaked spectra, it is shown that the armour may be designed by the formula when...

  16. Stability of Monolithic Rubble Mound Breakwater Crown Walls Subjected to Impulsive Loading

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke

    2012-01-01

    This paper evaluates the validity of a simple onedimensional dynamic analysis as well as a FEM model to determine the sliding of a rubble mound breakwater crown wall. The evaluation is based on a case example with real wave load time series and displacements measured from two-dimensional physical...... model tests. The outcome is a more reliable evaluation of the applicability of simple dynamic calculations for the estimation of sliding distances of rubble mound superstructures. This is of great practical importance since many existing rubble mound crown walls are subjected to increasing wave loads...

  17. Hydraulic Performance of an Innovative Breakwater for Overtopping Wave Energy Conversion

    Directory of Open Access Journals (Sweden)

    Claudio Iuppa

    2016-11-01

    Full Text Available The Overtopping BReakwaterfor Energy Conversion (OBREC is an overtopping wave energy converter, totally embedded in traditional rubble mound breakwaters. The device consists of a reinforced concrete front reservoir designed with the aim of capturing the wave overtopping in order to produce electricity. The energy is extracted through low head turbines, using the difference between the water levels in the reservoir and the sea water level. This paper analyzes the OBREC hydraulic performances based on physical 2D model tests carried out at Aalborg University (DK. The analysis of the results has led to an improvement in the overall knowledge of the device behavior, completing the main observations from the complementary tests campaign carried out in 2012 in the same wave flume. New prediction formula are presented for wave reflection, the overtopping rate inside the front reservoir and at the rear side of the structure. Such methods have been used to design the first OBREC prototype breakwater in operation since January 2016 at Naples Harbor (Italy.

  18. Wave pressure acting on V-shaped floating breakwater in random seas

    Science.gov (United States)

    Yu, Yang; Ding, Ning; Lin, Jie; Hou, Jiajia

    2015-12-01

    Wave pressure on the wet surface of a V-shaped floating breakwater in random seas is investigated. Considering the diffraction effect, the unit velocity potential caused by the single regular waves around the breakwater is solved using the finite-depth Green function and boundary element method, in which the Green function is solved by integral method. The Response-Amplitude Operator (RAO) of wave pressure is acquired according to the Longuet-Higgins' wave model and the linear Bernoulli equation. Furthermore, the wave pressure's response spectrum is calculated according to the wave spectrum by discretizing the frequency domain. The wave pressure's characteristic value corresponding to certain cumulative probability is determined according to the Rayleigh distribution of wave heights. The numerical results and field test results are compared, which indicates that the wave pressure calculated in random seas agrees with that of field measurements. It is found that the bigger angle between legs will cause the bigger pressure response, while the increase in leg length does not influence the pressure significantly. The pressure at the side of head sea is larger than that of back waves. When the incident wave angle changes from 0° to 90°, the pressure at the side of back waves decreases clearly, while at the side of head sea, the situation is more complicated and there seems no obvious tendency. The concentration of wave energy around low frequency (long wavelength) will induce bigger wave pressure, and more attention should be paid to this situation for the structure safety.

  19. Estimation of Wave Conditions Along a New Breakwater for the Hanstholm Harbour, Using the Numerical Model MILDwave

    DEFF Research Database (Denmark)

    Stratigaki, Vasiliki; Troch, Peter; Margheritini, Lucia

    2012-01-01

    Extension of the Hanstholm harbour (Denmark) is being planned, including the construction of a new breakwater. Within the general frame of the development plan of the harbour, numerical modelling has been carried out using the ild-slope model MILDwave developed at Ghent University, for estimating...... with analytical (Goda’ method) and numerical results (SWAN-1D)....

  20. Computer aided optimum design of rubble-mound breakwater cross-sections : Manual of the RUMBA computer package, release 1

    NARCIS (Netherlands)

    De Haan, W.

    1989-01-01

    The computation of the optimum rubble-mound breakwater crosssection is executed on a micro-computer. The RUMBA computer package consists of two main parts: the optimization process is executed by a Turbo Pascal programme, the second part consists of editing functions written in AutoLISP. AutoLISP is

  1. Model Testing and Reliability Evalution of the New Deepwater Breakwater at La Coruña, Spain

    DEFF Research Database (Denmark)

    Burcharth, Hans Falk; Maciñeira, Enrique; Canalejo, Pedro

    2003-01-01

    A new deepwater port development at Punta Langosteira near La Coruña is under design. Shelter is provided by a 2 km long rubble mound breakwater fully exposed to Atlantic waves. Max. water depth is 45 m, crownwall crest level is + 25 m and main armour blocks are 150 t cubes. Moorings for oil tank...

  2. Pressure-induced forces and shear stresses on rubble mound breakwater armour layers in regular waves

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2014-01-01

    measurements in the core material: (1) core material with an idealized armour layer made out of spherical objects that also allowed for detailed velocity measurements between and above the armour, and (2) core material with real rock armour stones. The same core material was applied through the entire...... and turbulence measurements showed that the large outward directed pressure gradients in general coincide, both in time and space, with the maximum bed-shear stresses on the armour layer based on the Reynolds-stresses. The bed-shear stresses were found to result in a Shields parameter in the same order......This paper presents the results from an experimental investigation of the pressure-induced forces in the core material below the main armour layer and shear stresses on the armour layer for a porous breakwater structure. Two parallel experiments were performed which both involved pore pressure...

  3. Reduction in Design Stability Number of Monolayer Armour Units for Singular Conditions of Projects in Rubble Mound Breakwaters

    Directory of Open Access Journals (Sweden)

    Hugo Juan Donini

    2015-07-01

    Full Text Available The evaluation of concrete single layer of breakwaters is based on the application of design coefficients obtained in laboratory tests, primarily two-dimensional and under controlled conditions. With the experience of more than 30 years in structures of this type in the world, it is important to compare the values of stability numbers used in the design with those who are in breakwaters as built. In this paper, update and increase the data collected with respect to previous publications, developing an analysis of particular situations in which the amour layer stability coefficients are reduced. A series of Accropode® and Core-LocTM recommendations concerning the design elements is also made. Also there are conclusions related to increases in the volume and the reduction in the number of blocks needed for different numbers of stability proposed.

  4. Wave Overtopping over Crown Walls and Run-up on Rubble Mound Breakwaters with Kolos Armour under Random Waves

    OpenAIRE

    A. Arunjith; S. A. Sannasiraj; V. Sundar

    2013-01-01

    The design of rubble mound structures like breakwaters and seawalls are influenced by the wave run-up and overtopping over them. The above phenomena largely depend on the type of the armour units as they directly interact with the incident waves. The hydrodynamic characteristics of various concrete armour units have been established by several researchers. A new armour block, ‘Kolos’, a modified version of Dolos, is considered in this study for a detailed investigation. An attempt is made to ...

  5. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Sang Kil Park

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (γν = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  6. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Park Sang Kil

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  7. A non-intrusive and continuous-in-space technique to investigate the wave transformation and breaking over a breakwater

    Directory of Open Access Journals (Sweden)

    Ferrari Simone

    2016-01-01

    Full Text Available To design longshore breakwaters, the evaluation of the wave motion transformations over the structures and of the energy they are able to absorb, dissipate and reflect is necessary. To characterize features and transformations of monochromatic wave trains above a breakwater, both submerged and emerged, we have designed and developed a non-intrusive and continuous-in-space technique, based on Image Analysis, and carried out an experimental campaign, in a laboratory flume equipped with a wave-maker, in order to test it. The investigation area was lighted with a light sheet and images were recorded by a video-camera. The working fluid was seeded with non buoyant particles to make it bright and clearly distinct from dark background and breakwater. The technique, that is based on a robust algorithm to identify the free surface, has showed to properly work also in prohibitive situations for traditional resistive probes (e.g., very shallow waters and/or breaking waves and to be able to measure the free surface all over the investigation field in a non-intrusive way. Two kind of analysis were mainly performed, a statistical and a spectral one. The peculiarities of the measurement technique allowed to describe the whole wave transformation and to supply useful information for design purposes.

  8. Functional and environmental design of detached, low crest level breakwaters; Diseno funcional y ambiental de diques exentos de baja cota de coronacion

    Energy Technology Data Exchange (ETDEWEB)

    Bricio Garberi, L.; Negro Valdecantos, V.; Diez Gonzalez, J. J.; Lopez Gutierrez, J. S.

    2010-07-01

    The research work as presented in this article covers the design of detached breakwaters since they constitute a type of coastal defense work with which to combat many of the erosion problems found on beaches in a stable, sustainable fashion. The main aim of this work is to formulate a functional and environmental (non structural) method of design enabling the fundamental characteristics of a detached breakwater to be defined as a function of the effect it is wished to induce on the coast whilst meeting social demands and preserving or improving the quality of the littoral environment. The general applicability of the method is also sought by means of considering relations between variables od different natures (climatic, geomorphologic and geometric) influencing the changes experienced on the coast after the detached breakwater has been built. The study of the relations between the different variables is carried out on the data from a abase of nineteen actual, existing detached breakwaters on the Spanish Mediterranean coastline and follows a methodology based on the implementation of non-dimensional monomials and on a search for relations of dependency between them. Finally, a discussion on the results obtained lead to a proposal for a design method that uses some of the graphic relations found between the variables studied with which the aforesaid main objective is achieved. (Author) 9 refs.

  9. Subtidal eelgrass/macroalgae surveys for the proposed breakwaters at the US Coast Guard Station at Ediz Hook, Washington, March 1993

    Energy Technology Data Exchange (ETDEWEB)

    Shreffler, D.K. [Battelle/Marine Sciences Lab., Sequim, WA (US)

    1993-05-01

    In 1993, the US Coast Guard proposed to construct two breakwaters and a debris boom to protect its existing pier and moored vessels inside Ediz Hook in Port Angeles Harbor, Washington. To assist the US Army Corps of Engineers -- Seattle District in determining the potential environmental impacts of the proposed breakwaters, Battelle/Marine Sciences Laboratory performed subtidal SCUBA surveys as specified in the Washington Department of Fisheries intermediate eelgrass/macroalgae habitat survey guidelines. The objectives of the subtidal surveys were to (1) quantify the shoot densities of eelgrass; (2) provide percent cover estimates for non-eelgrass macroalgae species; (3) develop a site map indicating the qualitative distribution of eelgrass/macroalgae species, substrate characterization, approximate depth contours, and the approximate location of the proposed project features; and (4) document the time and date of the surveys, turbidity/visibility, presence of invertebrate/vertebrate species, and anecdotal observations pertinent to habitat characterization of the project site. A total of 14 dives along 12 transects (T1--T12) were successfully completed between March 15 and March 17, 1993. Eelgrass was observed on all of the transects except T7 and T8 at the western debris barrier and T12 along the waterward margin of the existing T-pier. The vicinity of the proposed east breakwater had the highest eelgrass shoot densities (up to 89 shoots/m{sup 2}) observed by the divers. Macroalgae and invertebrate species diversity were also highest at the east breakwater site. The low eelgrass densities observed at the west debris barrier site (0 to 14 shoots/m{sup 2}) can be attributed mostly to the lack of suitable substrate. The existing layer of wood debris armoring the bottom at the west project site currently limits, and in the areas of heaviest deposition probably precludes, the growth of eelgrass. As was expected, no eelgrass was observed at the south breakwater site.

  10. Seasonal dynamics of fish assemblages on breakwaters and natural rocky reefs in a temperate estuary: consistent assemblage differences driven by sub-adults.

    Directory of Open Access Journals (Sweden)

    Ashley M Fowler

    Full Text Available Development of infrastructure around cities is rapidly increasing the amount of artificial substrate (termed artificial reef, 'AR' in coastal marine habitats. However, effects of ARs on marine communities remain unknown, because it is unclear whether ARs can maintain similar communities to natural reefs. We investigated whether well-established (> 30 years old breakwaters could consistently approximate fish assemblages on interspersed rocky reefs in a temperate estuary over 6 consecutive seasons using regular visual surveys between June 2009 (winter and November 2010 (spring. We examined whether assemblage differences between reef types were driven by differences in juvenile recruitment, or were related to differences in older life-stages. Assemblages on both reef types were dominated by juveniles (61% of individuals and sub-adults (34% of individuals. Seasonal fluctuations in assemblage parameters (species richness, diversity, sub-adult abundance were similar between reef types, and levels of species diversity and assemblage composition were generally comparable. However, abundance and species richness were consistently higher (1.9-7.6 and 1.3-2.6 times, respectively on breakwaters. These assemblage differences could not be explained by differences in juvenile recruitment, with seasonal patterns of recruitment and juvenile species found to be similar between reef types. In contrast, abundances of sub-adults were consistently higher (1.1-12 times at breakwaters, and assemblage differences appeared to be driven by this life-stage. Our results indicate that breakwaters in temperate estuaries are capable of supporting abundant and diverse fish assemblages with similar recruitment process to natural reefs. However, breakwaters may not approximate all aspects of natural assemblage structure, with differences maintained by a single-life stage in some cases.

  11. Wave Overtopping over Crown Walls and Run-up on Rubble Mound Breakwaters with Kolos Armour under Random Waves

    Directory of Open Access Journals (Sweden)

    A. Arunjith

    2013-06-01

    Full Text Available The design of rubble mound structures like breakwaters and seawalls are influenced by the wave run-up and overtopping over them. The above phenomena largely depend on the type of the armour units as they directly interact with the incident waves. The hydrodynamic characteristics of various concrete armour units have been established by several researchers. A new armour block, ‘Kolos’, a modified version of Dolos, is considered in this study for a detailed investigation. An attempt is made to establish empirical relationships for the estimation of wave overtopping discharges over crown wall and run-up on Kolosarmoured slope exposed to random wave from the results of a comprehensive experimental program. Further, the results are compared with that of a tested section with natural rocks as armour layer and with that of other investigators.

  12. On Methods of Establishing Design Diagrams for Structural Integrity of Slender Complex Types of Breakwater Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Howell, Gary J.

    1988-01-01

    Many of the recent dramatic failures of a number of large rubble mound breakwaters armoured with Dolosse and Tetrapods were caused by breakage of the concrete armour units. Breakage took place before the hydraulic stability of intact units in the armour layers expired. Thus there was not a balance...... was first presented by NRC (Timco 1981 ). Work based on direct strain-gauge measurement of stresses on large concrete model armour units was presented by Nishigori et al. in 1986.So far, none of the mentioned methods have produced general applicable tools for the design of armour layers. This is mainly...... an application of the method based on the results obtained from the extensive prototype research program with 42 t Dolosse at Crescent City performed by the U.S. Army Corps of Engineers WES Vicksburg (Howell 1986). The reason for and the object of this early presentation of the method is that, if accepted...

  13. Post-construction monitoring of a Core-Loc™ breakwater using tripod-based LiDAR

    Science.gov (United States)

    Podoski, Jessica H.; Bawden, Gerald W.; Bond, Sandra; Smith, Thomas D.; Foster, James

    2010-01-01

    The goal of the technology application described herein is to determine whether breakwater monitoring data collected using Tripod (or Terrestrial) Light Detection and Ranging (T-LiDAR) can give insight into processes such as how Core-Loc™ concrete armour units nest following construction, and in turn how settlement affects armour layer stability, concrete cap performance, and armour unit breakage.  A further objective is that this information can then be incorporated into the design of future projects using concrete armour units.  The results of this application of T-LiDAR, including the challenges encountered and the conclusions drawn regarding initial concrete armour unit movement will be presented in this paper.

  14. Environmental Impact Research Program. Ecological Effects of Rubble-Mound Breakwater Construction and Channel Dredging at West Harbor, Ohio (Western Lake Erie).

    Science.gov (United States)

    1985-09-01

    would provide new habitat that would be rapidly colonized by periphyton and benthic macro- -, invertebrates (macrozoobenthos). Although the environmental...consumed by invertebrates which are eaten by fish and therefore may attract fish to the breakwater. However, a nuisance aspect of the Ciadophora is that...Harbor, Ohio (August 1981-1983) Taxa* Percent Porifera (Spongil a) 0.01 Cnidaria (Hydra) 0.30 Rhabdocoela 0.35 Tricladida 0.16 Nemertinea 0.14 Nematoda

  15. STUDY OF EFFECTIVENESS OF BREAKWATER STRUCTURES OF THE “EASTERN PETROCHEMICAL COMPANY” JSC OIL REFINERY AND PETROCHEMICAL PLANTS PORT COMPLEX

    Directory of Open Access Journals (Sweden)

    Prikhod’ko Oleg Alekseevich

    2017-05-01

    Full Text Available The article presents the research of MGSU Corporation for testing of design solutions of the “Eastern petrochemical company” JSC oil refinery and petrochemical plants port complex using the physical modeling method. Construction of the marine terminal of the oil refinery and petrochemical plants port complex is planned to be on the Eastern shore of the Vostok Bay which is the part of Peter the Great Bay in the Sea of Japan. The port area is created by means of an artificial land site. The water area of the terminal will be guarded against sea waves by a breakwater. Experiments on the study of wave propagation in the port model water area at the Eastern and Western breakwaters were performed in the laboratory wave basin in three-dimensional layout, with the aim of obtaining of data about wave heights at berthing facilities. Effectiveness of the breakwater designs was studied in two-dimensional layout in a wave flume. During the port model construction all the designed waterworks as well as the project bathymetry of the port water area were reproduced at a scale of 1:100. Analysis of the experiment results with the slope protection embodiment version demonstrates that this engineering solution is able to withstand waves of the design parameters.

  16. Subsidence estimation of breakwater built on loosely deposited sandy seabed foundation: Elastic model or elasto-plastic model

    Directory of Open Access Journals (Sweden)

    Jianhua Shen

    2017-07-01

    Full Text Available In offshore area, newly deposited Quaternary loose seabed soils are widely distributed. There are a great number of offshore structures has been built on them in the past, or will be built on them in the future due to the fact that there would be no very dense seabed soil foundation could be chosen at planed sites sometimes. However, loosely deposited seabed foundation would bring great risk to the service ability of offshore structures after construction. Currently, the understanding on wave-induced liquefaction mechanism in loose seabed foundation has been greatly improved; however, the recognition on the consolidation characteristics and settlement estimation of loose seabed foundation under offshore structures is still limited. In this study, taking a semi-coupled numerical model FSSI-CAS 2D as the tool, the consolidation and settlement of loosely deposited sandy seabed foundation under an offshore breakwater is investigated. The advanced soil constitutive model Pastor-Zienkiewics Mark III (PZIII is used to describe the quasi-static behavior of loose sandy seabed soil. The computational results show that PZIII model is capable of being used for settlement estimation problem of loosely deposited sandy seabed foundation. For loose sandy seabed foundation, elastic deformation is the dominant component in consolidation process. It is suggested that general elastic model is acceptable for subsidence estimation of offshore structures on loose seabed foundation; however, Young's modulus E must be dependent on the confining effective stress, rather than a constant in computation.

  17. Morpholithodynamical changes of the beach and the nearshore zone under the impact of submerged breakwaters – a case study (Orłowo Cliff, the Southern Baltic

    Directory of Open Access Journals (Sweden)

    Agnieszka Kubowicz-Grajewska

    2015-04-01

    Based on the conducted research and analysis, it has been found that the construction has a minor impact on the modification of the shore and nearshore zone morpholithodynamics, which is evidenced by a sinuate shape of the shoreline and a relatively stable cape in the central part of the area, present both before (1966–2005 and after SBWs were built. Furthermore, the progressive abrasion, the lack of significant changes in the morphology and particle size distribution of the beach and the nearshore zone, as well as the fact that those changes are limited only to the immediate surroundings of the submerged breakwaters prove their neutral impact.

  18. Crablock Concrete Breakwater Armour Unit

    CSIR Research Space (South Africa)

    Phelp, D

    2012-02-01

    Full Text Available concrete armour units. This paper describes the development and use of CRABLOCK, which is similar to the Hexapod in shape (SPM, 2006). The results of physical model tests carried out at CSIR, in South Africa, are also presented and discussed....

  19. Kaumalapau Harbor, Hawaii, Breakwater Repair

    Science.gov (United States)

    2012-05-01

    multiple degrees of freedom related to ship motion ( surge , sway , heave, roll, pitch, and yaw), and the associated position corrections needed by an...conditions. Local barge operators were using multi-ton ballast weights on the barges fore and aft to counter the harbor surge during loading operations...harbor basin to measure the breakwater’s effectiveness in damping waves that interfere with loading operations. These wave data will be compared to

  20. Foundation Design of Caisson Breakwaters

    DEFF Research Database (Denmark)

    Groot, M.B. De; Andersen, K.H.; Burcharth, H. F.

    1996-01-01

    This document has been prepared as a part of the dissemination of results of the MCS-Project (Contract No. MAS2-CT92-0047) which was led by the University of Hannover (Coordinator: H. Oumeraci) within the 2nd Research Programme of the European Union (EU) on Marine and Science Technology. The supp...

  1. Pore Pressure Measurements inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    Large scale model tests have been performed in the LARGE WAVE CHANNEL (GWK) of the Coastal Research Centre (FZK).......Large scale model tests have been performed in the LARGE WAVE CHANNEL (GWK) of the Coastal Research Centre (FZK)....

  2. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten; Zanuttigh, B.; van der Meer, J.W.

    2005-01-01

    in a wave channel at small scale, and scale effects regarding wave transmission and reflection were studied in a wave channel at a large scale facility. The paper describes the experiments and associated databank with respect to objectives, test program, set-ups and measurements. Results, guidelines...

  3. Safety Aspects for Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.; Christiani, E.

    1996-01-01

    and possible level I and D code formats. In the following first the most important failure modes are briefly described, see section 2. It is assumed that the failure modes can be modelled by limit state functions. Wave load models are described in section 3. In section 5 uncertainties related to the parameters...

  4. Stability analysis of rubblemound breakwater using ANN

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Rao, S.; Manjunath, Y.R.; Kim, D.H.

    1993, Nielsen 1988). Networks have an ability to recognize the hidden pattern in the data and accordingly estimate the values. The biggest merit is its ability to deal with fuzzy information whose interrelation us ambiguous or whose functional...

  5. Structural Stability Of Detached Low Crested Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Kramer, Morten; Lamberti, Alberto

    2006-01-01

    determining armour stone size in shallow water conditions is given together with a rule of thumb for the required stone size in depth-limited design waves. Rock toe stability is discussed on the basis of prototype experience, hard bottom 2-D tests in depth-limited waves and an existing hydraulic stability...

  6. Case Study for Breakwater SSG Application

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Kofoed, Jens Peter

    -u-005, April 2008). The optimization of the structure has been done by maximizing the hydraulic efficiency and used by DMC for relative study on construction and installation. The overall efficiencies have been assessed using the simulation program SSG Power Simulation 2 (Meinert 2006) and used by DMC...

  7. Laboratory Experiments on Low-crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Zanuttigh, B.; van der Meer, J. W.

    2004-01-01

    The ducument describe 3D tests at scale 1:20 performed in the Laboratory at Department of Civil Engineering, Aalborg University.The wave obliquity was one of the main parameters, which were studied in the wave basin experiments. The experiments provide unique information about the influences of t...

  8. Structural Stability of Low-Crested Breakwaters

    DEFF Research Database (Denmark)

    Kramer, Morten

    A more and more widespread way to protect the coast against ongoing erosion is to build so called Low Crested Structures (LCS’s). Despite a large number of coast parallel LCS’s exist, the structural performance of these structures are not fully clarified. The LCS’s dealt with are coast parallel...

  9. Point Judith, Rhode Island, Breakwater Risk Assessment

    Science.gov (United States)

    2015-08-01

    trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are...height on 31 October 1991, made famous by the novel and feature movie, was ranked 15th for wave height but ranked 5th by surge. The maximum tidal

  10. Periodic Inspections of Cleveland Harbor East Breakwater, Ohio, and Burns Harbor North Breakwater, Indiana

    Science.gov (United States)

    2015-05-01

    hyperspectral imagery, and aerial photographs using the Coastal Zone Mapping and Imaging Lidar (CZMIL) system ( Tuell et al. 2010; Reif et al. 2013...0.7 meters (m) on land and shallow water and is 2 m in optically deep water ( Tuell et al. 2010; Wozencraft 2013). A Compact Airborne Spectrographic...204. Tuell , G., K. Barbor, and J. M. Wozencraft. 2010. Overview of the coastal zone mapping and imaging lidar (CZMIL); A new multisensory airborne

  11. Navier-Stokes wave models for investigations of breakwater characteristics

    CSIR Research Space (South Africa)

    Cannoo, BR

    2008-03-01

    Full Text Available observations, including turbulence in surging and plunging waves, is encouraging, but quantitative comparisons are still to be made. Loads on a semi-submerged beam are modelled in preparation for studies of the dolos geometry...

  12. Landward Distribution of Wave Overtopping for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2006-01-01

    Overtopping data from seven model test projects has been analyzed with respect to the landward spatial distribution of the overtopping discharge. In total more than 1000 overtopping tests have been analysed and a formula derived for prediction of the landward distribution of overtopping behind ru...... rubble mound structures with a super structure. The analysis led to the conclusion that although the overtopping discharge, for identical wave heights, decreases with increasing wave steepness, then the maximum travel distance increases with increasing wave steepness....

  13. Stability prediction of berm breakwater using neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Rao, S.; Manjunath, Y.R.

    .manjunatha@gmail.com Seventh International Conference on Coastal and Port Engineering in Developing Countries - Best practices in the coastal environment. Proceedings. 24-28 February 2008. Dubai Municipality; Dubai; UAE; 11 pp. 2 Table 1: ANN...

  14. Numerical Study on Tsunami Hazard Mitigation Using a Submerged Breakwater

    OpenAIRE

    Taemin Ha; Jeseon Yoo; Sejong Han; Yong-Sik Cho

    2014-01-01

    Most coastal structures have been built in surf zones to protect coastal areas. In general, the transformation of waves in the surf zone is quite complicated and numerous hazards to coastal communities may be associated with such phenomena. Therefore, the behavior of waves in the surf zone should be carefully analyzed and predicted. Furthermore, an accurate analysis of deformed waves around coastal structures is directly related to the construction of economically sound and safe coastal struc...

  15. Numerical study on tsunami hazard mitigation using a submerged breakwater.

    Science.gov (United States)

    Ha, Taemin; Yoo, Jeseon; Han, Sejong; Cho, Yong-Sik

    2014-01-01

    Most coastal structures have been built in surf zones to protect coastal areas. In general, the transformation of waves in the surf zone is quite complicated and numerous hazards to coastal communities may be associated with such phenomena. Therefore, the behavior of waves in the surf zone should be carefully analyzed and predicted. Furthermore, an accurate analysis of deformed waves around coastal structures is directly related to the construction of economically sound and safe coastal structures because wave height plays an important role in determining the weight and shape of a levee body or armoring material. In this study, a numerical model using a large eddy simulation is employed to predict the runup heights of nonlinear waves that passed a submerged structure in the surf zone. Reduced runup heights are also predicted, and their characteristics in terms of wave reflection, transmission, and dissipation coefficients are investigated.

  16. Numerical Study on Tsunami Hazard Mitigation Using a Submerged Breakwater

    Directory of Open Access Journals (Sweden)

    Taemin Ha

    2014-01-01

    Full Text Available Most coastal structures have been built in surf zones to protect coastal areas. In general, the transformation of waves in the surf zone is quite complicated and numerous hazards to coastal communities may be associated with such phenomena. Therefore, the behavior of waves in the surf zone should be carefully analyzed and predicted. Furthermore, an accurate analysis of deformed waves around coastal structures is directly related to the construction of economically sound and safe coastal structures because wave height plays an important role in determining the weight and shape of a levee body or armoring material. In this study, a numerical model using a large eddy simulation is employed to predict the runup heights of nonlinear waves that passed a submerged structure in the surf zone. Reduced runup heights are also predicted, and their characteristics in terms of wave reflection, transmission, and dissipation coefficients are investigated.

  17. Scaling of Core Material in Rubble Mound Breakwater Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.; Troch, P.

    1999-01-01

    The permeability of the core material influences armour stability, wave run-up and wave overtopping. The main problem related to the scaling of core materials in models is that the hydraulic gradient and the pore velocity are varying in space and time. This makes it impossible to arrive at a fully...... correct scaling. The paper presents an empirical formula for the estimation of the wave induced pressure gradient in the core, based on measurements in models and a prototype. The formula, together with the Forchheimer equation can be used for the estimation of pore velocities in cores. The paper proposes...... that the diameter of the core material in models is chosen in such a way that the Froude scale law holds for a characteristic pore velocity. The characteristic pore velocity is chosen as the average velocity of a most critical area in the core with respect to porous flow. Finally the method is demonstrated...

  18. State of the Art in the Conceptual Design of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    2000-01-01

    Design and construction of coastal structures have always been a challenge as engineers are working in still more exposed locations, and the former acceptance of some failures caused by the inpredictable sea is no more valid . Today it is generally expected that the coastal engineer can cope...... with the vagaries of nature and produce structures which will survive and function for several generations. The design tools available to us are better than ever and we can, in a rational way, deal with the uncertainties inherent in sea states and structural responses. Provided no failure mode is overlooked we can...... in fact design on the basis of target probability of specific damage within structure lifetime, identified by economic optimization....

  19. An Alternative Stability Equation For Rock Armoured Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue; Burcharth, H. F.

    2000-01-01

    equations and model test results still exists. When turning toward prototype the situation is even worse. With the objective to reduce some of the variability an alternative approach based on force considerations is presented. The paper will describe a new stability equation for rock armoured slopes derived...

  20. Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Walle, B. Van de

    2001-01-01

    Physical processes such as wave run-up and wave overtopping are very important with regard to the design of sloping coastal structures. However, these are not yet fully understood. Preliminary prototype measuring campaigns (1993-1996) indicated clearly higher wave run-up values than the values fo...... are noticed....

  1. Flow in Porous Media with Special Reference to Breakwater Structures

    DEFF Research Database (Denmark)

    Andersen, O. Holst

    A literature study concerning porous flow is carried out. For the stationary case, the hydraulic radius theory, for which some justification can be given based on Navier-Stokes equations, appears to be adequate. Three different porous flow regimes are identified and the associated flow resistance...... coefficients are found from the literature. For the non-stationary flow case, existing expressions are discussed, and with the aim of decribing the inertia term a new analogy based on cylinders/spheres is presented. The predicted variation of the virtual mass coefficient with the porosity compares to a series...

  2. Floating Breakwaters: State-of-the-Art Literature Review.

    Science.gov (United States)

    1981-10-01

    waves, vertically weighted to trap long-period waves) (Fig. IbO ). The valve sheets are shown in 219 Horizontal Wave Trap Vertical Wave Trap Anchor...channels, the mooring line consisted of a solid strand of stainless steel music wire (0.01-inch diameter). For tests in the 9-foot channel, the line

  3. Horizontal Coherence of Wave Forces on Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Archetti, Renata; Lamberti, Alberto; Martinelli, Luca

    2001-01-01

    Evaluation of spatial coherence of breaking waves is of great importance and of recent interest.......Evaluation of spatial coherence of breaking waves is of great importance and of recent interest....

  4. Wave Loadings Acting on an Innovative Breakwater for Energy Production

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Ciardulli, F.; Buccino, M.

    2011-01-01

    The paper reports on 2D small scale experiments conducted to investigate wave loadings acting on a pilot project of device for the conversion of wave energy into electricity. The conversion concept is based on the overtopping principle and the structure is worldwide known with the acronym SSG...

  5. Stability of Reshaping Breakwaters with Special Reference to Stone Durability

    DEFF Research Database (Denmark)

    Frigaard, Peter; Hald, Tue; Burcharth, H. F.

    1996-01-01

    movements. Also tensile stresses occur, as a result of stone against stone impact are discussed in order to make a more close connection between wave climate, stone movements and abrasion/breakage. Finally, a comparison to selected prototype structures is made to compare the armour stone movement model...

  6. Page 1 Irregular waves and submerged breakwater 353 These ...

    Indian Academy of Sciences (India)

    Bao (1969) reported that this simple spectrum corresponds well with measured wave spectra from the Black sea and Atlantic Ocean. Mihailov et al (1974) has shown that it corresponds to Caspian Sea conditions also. This spectrum has been used in many investigations (Mihailov et al 1969, 1974; Wiemer & Halfin 1977; ...

  7. Periodic Inspections of Hilo, Kahului, Laupahoehoe, and Nawiliwili Breakwaters, Hawaii

    Science.gov (United States)

    2011-10-01

    Flute -shank – break occurs across the fluke near the intersection of the fluke and shank (Figure 24); ERDC/CHL TR-11-8 23 Figure 23. Typical...elevation lowers for last 200 ft 87 98+50 OS, fissure extending from crest down to waterline; about 2 ft wide Note: Erosion at head from centerline to

  8. Variação do número de estômatos e micropêlos em Paspalum vaginatum Sw: em relação às condições abióticas numa marisma do estuário da Lagoa dos Patos, RS-Brasil Variation in the number of stomata and microhairs of Paspalum vaginatum Sw: en relation to abiotic conditions in a breakwater in the Lagoa dos Patos estuary, RS-Brazil

    Directory of Open Access Journals (Sweden)

    Eleci de Oliveria Bastos

    1992-12-01

    Full Text Available Paspalum vaginatum Sw., gramínea perene, estolonífera, com folhas anfistomáticas e pequenas é característica de pântanos salgados, crescendo em condições estressantes na marisma da lagoa dos Patos, molhe oeste da Barra do Rio Grande, RS. Foram feitas contagens mensais de estômatos e micropêlos nas superfícies adaxial e abaxial das lâminas e relacionadas às características abióticas do ambiente. O número de micropêlos da superfície foliar abaxial variou significativamente e diretamente com a temperatura da água intersticial junto às rizosferas. Estes, porém, não mantiveram correlação com a salinidade intersticial. Os resultados sugerem que a espécie seja uma halófita facultativa. O número de estômatos da superfície abaxial manteve um relacionamento inverso com a pluviosidade. Paspalum vaginatum, apresenta-se como uma espécie com características xeromórficas.Paspalum vaginatum Sw., a perennial, stoloniferous grass with small leaves presenting stomata on both epidermises is characteristic of salt marshes, growing under stressful conditions near the west breakwater of the Rio Grande outlet, Lagoa dos Patos, Rio Grande do Sul, Brazil. Monthly counts of stomata and microhairs on the adaxial and abaxial surfaces were related to the abiotic characteristics of the enviroment. The number of microhairs of the abaxial leaf surface varied significantly and directly with interstitial water temperature close to the rhyzosphere. However, these counts did not correlate with the interstitial salinity. The results suggest that the species is a facultative halophyte. Stomata counts of the abaxial surface showed an inverse relation to precipitation. Paspalum vaginatum appears to be a species with xeromorphic characteristics.

  9. Ecology and Distribution of the Benthic Community on the Monterey Breakwater, Monterey, California.

    Science.gov (United States)

    1981-03-01

    further subdivisions (i.e. classes, families, orders) given IIfor clarity. The invertebrate keys found in Smith and Carltohi (1975) were used in making...insculupta and Bugula californica were the dominant invertebrates . There were fewer quadrats containing rubble on the inner transect than the outer...Numbers given in Appendix C P Present Numbers were impossible to determine 99 APPENDIX C SPECIES LIST ANIMALS PORIFERA DEMOSPONGIAE Halisarca §R. Found

  10. Two-Dimensional Model Test Study of the New Caisson Breakwater at Playa Blanca, Lanzarote

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    This report present the results of 2-D physical model tests (length scale 1:42.5) carried out in a wave flume at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted b...

  11. Three-Dimensional Model Test Study of the New Breakwaters at Playa Blanca, Lanzarote

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Garborg, Karsten; Stagsted, Esben Rubech

    This report present the results of 3-D physical model tests (length scale 1:42.5) carried out in a wave bassin at Department of Civil Engineering, Aalborg University (AAU) on behalf of SENER Ingenera y Sistemas S.A. Associate Prof. Thomas Lykke Andersen was in charge of the model tests, assisted ...

  12. Power Production from Integration of SSG in a Breakwater at Liseleje

    DEFF Research Database (Denmark)

    Borgarino, Bruno; Kofoed, Jens Peter

    This report presents the steps carried out in order to propose a SSG setup at Liseleje location. The goal is to give an estimation of the available power and  flow in the harbour. These data will assist the projects managers in their applications for funds and consents. Because the project...

  13. Damage level prediction of non-reshaped berm breakwater using ANN, SVM and ANFIS models

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; SubbaRao; Harish, N.; Lokesha

    Marine Structures Laboratory, Department of Applied Mechanics and Hydraulics, NITK, Surathkal, India. Soft computing techniques like Artificial Neural Network (ANN), Support Vector Machine (SVM) and Adaptive Neuro Fuzzy Inference system (ANFIS) models...

  14. Large Scale Experiments on the Interaction of a Caisson Breakwater with Breaking Waves

    DEFF Research Database (Denmark)

    Stagonas, Dimitris; Marzeddu, Andrea; Buccino, Mariano

    2014-01-01

    measurements were complimented with high speed and high definition video records. ln addition, a pressure mapping system employing tactile pressure sensors was deployed in cornbination with force panels, both positioned at still water level. Although at a very early stage, data analysis yields promising...

  15. Why do we not have a Consistent Design Method for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    probability density functions of the involved parameters supplied with statistical information on the related persistance. The following presentation is not in accordance with this since each parameter is treated separately. This is done of the sake of simplicity and also because it will still serve the main...

  16. On The Use Of High-Density Rock In Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.

    2005-01-01

    Natural rock with high density is widely used in the Scandinavian countries. However, the use of natural rock with density higher than 2:9t=m3 is ordinarily associated with some kind of problem solving, e.g. where normal density stones have to be replaced with heavier stones without increasing...... the construction volume or layer thickness. Most common design formulae do not give a clear conclusion on the in°uence of the rock density on the stability. The present paper presents results of small and large scale model tests in which is used rock with different densities. It is shown that the positive effect...

  17. Analysis of Wave Reflection from Wave Energy Converters Installed as Breakwaters in Harbour

    DEFF Research Database (Denmark)

    Zanuttigh, B.; Margheritini, Lucia; Gambles, L.

    2009-01-01

    loads on the structure, i.e. better survivability. Nevertheless these devices must comply with the requirements of harbour protection structures and thus cope with problems due to reflection of incoming waves, i.e. dangerous sea states close to harbors entrances and intensified sediment scour, which can...... lead to structure destabilization. The present paper aims to analyse wave reflection from OWC and Sea Slot-cone Generator (SSG) converters, based on experimental results obtained in 2D and 3D facilities. The applicability of formulae available in the literature and derived from costal structures...

  18. Epifaunal Community Development on Great Lakes Breakwaters: An Engineering with Nature Demonstration Project

    Science.gov (United States)

    2014-08-01

    302–313. Chapman M. G. and D. J. Blockley. 2009. Engineering novel habitats on urban infrastructure to increase intertidal biodiversity . Oecologia...Ecologically informed engineering reduces loss of intertidal biodiversity on artificial shorelines. Environ. Sci. Technol. 45:8204–8207. Chapman M. G. and A

  19. Littoral Hydrodynamics and Sediment Transport Around a Semi-Permeable Breakwater

    Science.gov (United States)

    2015-09-18

    primary access channels within the marina basins were also surveyed. 2.2 ADCP measurements Two Acoustic Doppler Current Profilers ( ADCPs ) were...Figure 1). The current data were collected from both ADCPs , and water level and directional wave data were collected on the ocean side. Due to...instrument failure, the outside ADCP collected only about six days of data. Figure 1 Bathymetric and LiDAR survey area. Red dots show the location of

  20. Experimental study of 2D scour and its protection at a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    2000-01-01

    investigated for the following cases: (1) the protection apron with one layer of stones and (2) that with several layers of stones. The mechanism of slumping down of stones of the protection apron was also considered. The results of the toe protection study are given in the form of diagrams....

  1. Estimating transmitted waves of floating breakwater using support vector regression model

    Digital Repository Service at National Institute of Oceanography (India)

    Mandal, S.; Hegde, A.V.; Kumar, V.; Patil, S.G.

    to diameter of pipes (S/D). The radial basis functions performed well than the polynomial function in the regressive support vector machine as the kernel function for the given set of data. The support vector regression model gives the correlation coefficients...

  2. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    The scientific progress of our understanding of the interaction between coastal structures and the sea has greatly improved in the recent years. The present state of knowledge includes structural and financial optimization of the structures based on reliability evaluations. The first requirement...

  3. Influence of the density of placement on the stability of armour layers on breakwaters

    NARCIS (Netherlands)

    Van den Bosch, A.; D' Angremond, K.; Verhagen, H.J.; Olthof, J.

    2002-01-01

    Studies on the stability of the amour layer (d’Angremond et. al. [1999] revealed the importance of density of placement. The current research focuses on the influence of the density of placement on the stability of cubes in a double armour layer and tetrapods and rocks in a single armour layer. The

  4. Optimum Safety Levels and Design Rules for the Icelandic-Type Berm Breakwater

    DEFF Research Database (Denmark)

    Sigurdarson, Sigurdur; van der Meer, Jentsje W.; Burcharth, Hans F.

    2009-01-01

    strategies and possible failure with corresponding downtime have been taken into account, as well as actual market prices (in Iceland and Norway) for rack material and construction. Calculations show that low stability numbers for the largest rock armour layer give the optimal safety level....

  5. Portable floating breakwater for controlling bar formation and sediment transport near tidal inlets

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; Krishnakumar, V.; Swamy, G.N.

    stream_size 4 stream_content_type text/plain stream_name Inst_Eng_India_J_76_185.pdf.txt stream_source_info Inst_Eng_India_J_76_185.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  6. Characterization and properties of breakwater structures modelled by a physics engine

    CSIR Research Space (South Africa)

    Greben, JM

    2010-01-01

    Full Text Available these structures are exposed to (wave) forces of varying magnitude. The authors found that the damage is roughly proportional to the force squared, and that there is not a clear transition point where one can talk of the collapse of the structure. A range...

  7. Three-Dimensional Model Test Study on the Existing Caisson Breakwater at Port of Castellon, Spain

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    This report present the results of 3-D physical model tests (length scale 1:60) carried out in a wave basin at Department of Civil Engineering, Aalborg University (AAU) on behalf of the client; BP OIL ESPAÑA. Associate Prof. Thomas Lykke Andersen and M.Sc. Jørgen Quvang Harck Nørgaard were in cha...

  8. Geotechnical Failure of a Concrete Crown Wall on a Rubble Mound Breakwater Considering Sliding Failure and Rupture Failure of Foundation

    DEFF Research Database (Denmark)

    Christiani, E.; Burcharth, H. F.; Sørensen, John Dalsgaard

    1995-01-01

    Sliding and rupture failure in the rubble mound are considered in this paper. In order to describe these failure modes the wave breaking forces have to be accounted for. Wave breaking forces on a crown wall are determined from Burcharth's wave force formula Burcharth (1992). Overtopping rates...... in friction based soil. Rupture failure modes for a crown wall with a plane base and a crown wall with an extended leg on the seaward side will be formulated. The failure modes are described by limit state functions. This allows a deterministic analysis to be performed....

  9. Effect of water depth on the performance of intelligent computing models in predicting wave transmission of floating pipe breakwater.

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.

    (children). In cross over, chromosomes are paired randomly. The intermediate crossover principle is used and offspring’s are produced according to the following rule: Offspring = parent1 ± (parent2 – parent1) (15) Where α is the scaling factor chosen...

  10. Hybrid genetic algorithm tuned support vector machine regression for wave transmission prediction of horizontally interlaced multilayer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.; Muruganandam, A.

    (Holland, 1975) was used to select chromosomes for reproduction. ii) [Crossover]: with crossover probability cross over the parents to form new offspring’s (children). In cross over, chromosomes are paired randomly. The intermediate crossover principle...

  11. Neuro-fuzzy based approach for wave transmission prediction of horizontally interlaced multilayer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.; Alavandar, S.

    University New York City, NY 10003-6603 and Systems Neurobiology Laboratory Salk Institute for Biological Studies La Jolla, CA 92037. A. Srinivasan and M.J. Nigam, Neuro-fuzzy based approach for inverse kinematics solution of industrial robot manipulators...

  12. Reliability Evaluation of a Concrete Crown Wall on a Rubble Mound Breakwater considering Sliding Failure, Overturning and Rupture Failure of the Foundation

    DEFF Research Database (Denmark)

    Christiani, E.; Sørensen, Jørgen S.; Burcharth, Hans F.

    1994-01-01

    Wave breaking forces on a crown wall will be determined from Burcharth 's wave force formula. Based on these formulae a deterministic design is found. A reliability evaluation of the same structure is then performed using a level II FORM analysis. In this only the failure modes sliding1 overturning...

  13. Genetic algorithm based support vector machine regression in predicting wave transmission of horizontally interlaced multi-layer moored floating pipe breakwater

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.

    with crossover probability crossover of the parents is done to form new offspring’s (children). In cross over, chromosomes are paired randomly. The intermediate crossover principle is used and offspring’s are produced according to the following rule...

  14. Repair, Evaluation, Maintenance, and Rehabilitation Research Program. Laboratory Techniques for Evaluating Effectiveness of Sealing Voids in Rubble-Mound Breakwaters and Jetties with Grouts and Concretes

    Science.gov (United States)

    1990-03-01

    Ship Repairg. U, S. Dept. of Labor FLAS PONT 95*7 C..C. AUT01GNIT ION. FLAMMABLE LIMITS IN AlIA. % by volumeLOEUPR EXTINGUISHING MEDIA Foam , dry...distribution of the sand component, (b) percent bitumen , (c) percent voids, (d) density, (e) specific gravity, and (f) percent water absorption. Table 6...Percent bitumen 9.0 12.6 12.0 Pen grade of removed bitumen 20 30 Percent voids of total mixture 6.2 Percent voids filled 76.2 Density, lb/cu ft 142.5

  15. Numerical modelling of structures of dolosse and their interaction with waves

    CSIR Research Space (South Africa)

    Greben, JM

    2008-11-01

    Full Text Available The authors have applied various numerical techniques to describe the stability of breakwater structures under the exposure of waves. These studies are intended to get a better understanding of the parameters playing a role in breakwater stability...

  16. Vermilion Harbor, Ohio. Condition Survey Report. Study of the Impact of the Offshore Breakwater on A. Municipal Water Supply. B. Swimming Area and Beaches. C. Ice Jam Flooding. D. Free-Flow Flooding. E. Sedimentation. F. Navigation. G. Aesthetics.

    Science.gov (United States)

    1982-09-01

    that might be worth investi- gating is the beach nourishment method used at Cedar Point a few years ago. Specially shaped solid concrete units were...private citizens, have to fight a government agency, to get one of their "goofs" corrected? We thank you for reading the attached, and for any help that...R!VEESIDE DRINVE and Olympic Club Under the orders of the Corps the Cost was standing ont the monster that will residents evrcuated their homes

  17. Material, Structural Design of Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    Stone and concrete are two materials generally used for the construction of rubble mound breakwaters. This paper deals with concrete only.......Stone and concrete are two materials generally used for the construction of rubble mound breakwaters. This paper deals with concrete only....

  18. Permeability of Rubble Mound Material

    DEFF Research Database (Denmark)

    Williams, A.F.; Burcharth, H. F.; Adel, H. den

    The flow of water through the pores of rubble mound breakwaters has two effects upon breakwater performance. The pore pressures generated within the rubble material will effect the stability of the mound. The flow of water in and out of the pores plays a critical part in the dissipation of wave...... energy....

  19. Wave Reflection

    DEFF Research Database (Denmark)

    Helm-Petersen, J.; Frigaard, Peter

    1994-01-01

    This report is Aalborg University's first contribution to the MAS2-CT92 project: Full scale dynamic load monitoring of rubble mound breakwaters.......This report is Aalborg University's first contribution to the MAS2-CT92 project: Full scale dynamic load monitoring of rubble mound breakwaters....

  20. Safety of Marine Structures

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1990-01-01

    of a "future safe" design code for exposed marine structures like breakwaters should be different from the ones usually applied in modern design standards for conventional structures within civil engineering. Moreover, results from ongoing development of a design code for rubble mound breakwaters are presented....

  1. Experimental Study of Wave Field Around the Outer Part of a Rubble Mound Roundhead Solution for the new Port of La Coruña at Punto Langosteira

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Pedersen, Thomas Schmidt

    The wave agitation in the port and at the entrance to the port depends on the length of the outer part of the breakwater (west of the spur breakwater) and on the type of structure, e.g. caissons or rubble mound. In the present study is investigated the wave field around a rubble mound head armoured...

  2. Application to Representative Structures. Other Representative Structures: Mutsu-Ogawara, Niigata East and West

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.

    1999-01-01

    Reliability analyses are performed for three Japanese vertical wall breakwaters in this chapter. Only the geotechnical failure modes described in chapter 3 are investigated. For none of the breakwaters detailed data are available for the wave climate and for the soil conditions. Therefore...

  3. 33 CFR 207.480 - Lake Huron, Mich.; Harbor of refuge, Harbor Beach; use and navigation.

    Science.gov (United States)

    2010-07-01

    ...) Passenger boats will, in general, have the preference as to location and attention by the officer in charge... floating property making fast to the breakwater must at once place such fenders between themselves and the... piece of floating property made fast to the breakwater, or anchored in the harbor, must keep outboard...

  4. Numerical simulations of tsunami waves impacts on Ulee Lheue Harbour in Banda Aceh-Indonesia

    Science.gov (United States)

    Fachrurrazi; Syamsidik; Al'ala, M.; Mahardi, W.

    2017-02-01

    This paper reports the effects of 2004 Indian Ocean tsunami onto the Ulee Lheue harbour facility, Banda Aceh - Indonesia. The breakwater that had damaged after tsunami were rebuilt into its original design once more due to UNDP funding source. As the existing construction knowing how much the chance it stands againts the tsunami in various terms would be decent for further improvement. This research aim is to measure the capabilities of the breakwater againts the various tsunami scenario. performing the numerical simulation to analyze the hydrodynamics we used both COMCOT and Delft3D-flow for tsunami propagation in line with the hydrodynamics. Several observation points were deployed representing each part of the breakwater. The process revealed that the breakwater only able to hold 8.0 Mw induced wave from overtopping. uniquely when 8.2 Mw tsunami wave strikes the breakwater till overtopped but not giving enough energy to move the boulder aside. Potential movement of the boulder occurred when the 8.4 Mw tsunami wave come through the breakwater produced 77.12 m (5.88 %) damaged structure. The 8.6 Mw single fault highest magnitude gave 209.32 m long (15.97%) destruction upon this Ulee Lheue Harbour breakwater.

  5. Directional waverider buoy in Indian waters - Experiences of NIO

    Digital Repository Service at National Institute of Oceanography (India)

    AshokKumar, K.; Diwan, S.G.

    Information on directional waves is extremely important in the design of harbour structures, such as breakwaters and jetties and to study the sediment transport pattern. Till recent days our country has been using waverider buoys which give all wave...

  6. Variations in wave direction estimated using first and second order Fourier coefficients

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Anand, N.M.

    In most design applications such as alignment of the berthing structure and breakwater alignment, it becomes necessary to determine the direction of design wave. There are two different approaches to determine wave direction. One involves the use...

  7. The Importance of Pressure Sampling Frequency in Models for Determination of Critical Wave Loadings on Monolithic Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Meinert, Palle

    2008-01-01

    Wave induced pressures on model scale monolithic structures like caissons and concrete superstructures on rubble mound breakwaters show very peaky variations, even in cases without impacts from slamming waves....

  8. Coastal Harbors Modeling Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Coastal Harbors Modeling Facility is used to aid in the planning of harbor development and in the design and layout of breakwaters, absorbers, etc.. The goal is...

  9. Wave modelling for the North Indian Ocean using MSMR analysed winds

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; Sudheesh, K.; Rupali, S.P.; Babu, M.T.; Jayakumar, S.; Saran, A.K.; Basu, S.K.; Kumar, R.; Sarkar, A.

    are very essential for activities such as exploitation of natural resources, ship-routing, design of harbors, breakwaters and jetties, loading and unloading of ship?s cargo and estimation of sediment transport. Adequate reliable wind and wave data has...

  10. 78 FR 78353 - Hydro Green Energy, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Science.gov (United States)

    2013-12-26

    ... vertical access tunnel approximately 400 feet high and 30 feet in diameter; (9) a breakwater constructed... the ``eLibrary'' link of Commission's Web site at http://www.ferc.gov/docs-filing/elibrary.asp . Enter...

  11. 78 FR 78355 - Hydro Green Energy, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

    Science.gov (United States)

    2013-12-26

    ... vertical access tunnel approximately 400 feet high and 30 feet in diameter; (9) a breakwater constructed... the ``eLibrary'' link of Commission's Web site at http://www.ferc.gov/docs-filing/elibrary.asp . Enter...

  12. 77 FR 30891 - Special Local Regulations and Safety Zones; Recurring Events in Northern New England

    Science.gov (United States)

    2012-05-24

    ...'' W (NAD 83). Ellis Short Sand Park Trustee Fireworks Event Type: Fireworks Display. Sponsor: William...]36'25'' W (NAD 83). Rockland Breakwater Swim Event Type: Swim Event. Sponsor: Pen-Bay Masters. Date...

  13. 78 FR 6317 - Public Utility District No. 1 Chelan County; Notice of Application for Amendment of License and...

    Science.gov (United States)

    2013-01-30

    ... extending three existing docks and installing two new docks. A total of approximately 115 steel piles will be installed for the new docks. Concrete panel walls associated with a new fixed breakwater system...

  14. Local scour at roundhead and along the trunk of low crested structures

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen; Lamberti, Alberto

    2005-01-01

    not exhibit the pattern experienced in the case of emerged breakwaters where the scour and deposition areas are bcorrelatedQ with the nodal and antinodal points of the standing wave in front of the structure. Furthermore, it was found that scour occurs not only at the offshore side of the breakwater but also...... observations undertaken in the present study. Recommendations are made for toe protection for both the trunk scour and the roundhead scour....

  15. Zonação de comunidade bêntica do entremarés em molhes sob diferente hidrodinamismo na costa norte do estado do Rio de Janeiro, Brasil Zonation of intertidal benthic communities on breakwaters of different hydrodynamics in the north coast of the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno P. Masi

    2008-12-01

    Full Text Available O presente estudo pretende comparar a distribuição vertical da comunidade bêntica na zona entremarés em dois locais compostos por matacões graníticos caracterizados por hidrodinâmica distinta, reflexo da diferença na orientação dos molhes nas praias do Farol de São Tomé (Píer e na Barra do Furado (Barra, norte do Estado do Rio de Janeiro. Quadrados de 400 cm² foram sobrepostos ao longo de três perfis verticais de ambos os sítios e amostrados através do método de fotoquadrats, desde o nível 0,2 m da maré até o limite superior de Littorina spp. O limite superior dos organismos marinhos foi ampliado na Barra (3,8 m em relação ao Píer (2,2 m. Quanto à composição taxonômica, nove espécies foram comuns. Chaetomorpha sp., Chondracanthus teedii (Mertens ex Roth Fredericq e Grateloupia sp. foram exclusivas na Barra, enquanto Tetraclita stalactifera (Lamarck, 1818, Fissurella clench, Gracilaria domingensis (Kützing Sonder ex Dickie e Hypnea musciformis (Wulfen in Jacqu. Lamouroux ocorreram somente no Píer. Em ambos os locais, a riqueza e a diversidade de espécies foram superiores nos quadrados intermediários. Os maiores valores foram registrados na Barra. As maiores diferenças nos agrupamentos entre faixas equivalentes de locais distintos ocorreram na faixa eulitorânea superior, seguida pela faixa eulitorânea inferior e franja sublitorânea. Apenas a orla litorânea não revelou diferença significativa entre os locais, mas uma maior extensão desta franja e da faixa eulitorânea superior era bastante evidente. As demais faixas na Barra do Furado foram caracterizadas em grande parte por espécies típicas de ambientes mais expostos como Chaetomorpha sp. na faixa eulitorânea superior e Perna perna (Linnaeus, 1758 na eulitorânea inferior, além de C. teedii e Ulva fasciata Delile, 1813 na franja sublitorânea. No Píer, as diferentes faixas apresentavam distribuição eqüitativa, refletindo um ambiente menos estressante. As diferenças observadas na distribuição vertical dos organismos bênticos, principalmente na extensão das faixas superiores, evidenciam condições de exposição a ondas variáveis.The present study aims to compare the vertical distribution of intertidal benthic communities in two sites composed by granitic boulders with distint hydrodynamics due to different wave swells at Farol de São Tomé (Pier and Barra do Furado beaches (Barra, both in northern state of Rio de Janeiro. Quadrats of 400 cm² were overlapped along three vertical profiles on each site and were sampled by the photoquadrat method from 0.2 m of the tide level to the upper limit of Littorina spp. The upper limit of the marine organisms was higher at Barra site (3.8 m than at Píer site (2.2 m. Nine species were common to both sites. Chaetomorpha sp., Chondracanthus teedii (Mertens ex Roth Fredericq, and Grateloupia sp. were unique to Barra, whereas Tetraclita stalactifera (Lamarck, 1818, Fissurella clench, Gracilaria domingensis (Kützing Sonder ex Dickie, and Hypnea musciformis (Wulfen in Jacqu. Lamouroux occurred only at Píer boulders. On both sites species richness and diversity were superior at the intermediate quadrats of the intertidal zone. The highest values were recorded at Barra. The most pronounced assemblage differences between equivalent areas of either site occurred on the lower upper eulittoral band followed by the lower eulittoral and the sub-littoral fringe, respectively. The littoral fringe assemblage was the only one that did not show significant differences among the studied sites, yet a larger range of this fringe and the upper eulittoral band at Barra was quite evident. This site was mostly characterized by species of more exposed areas, such as Chaetomorpha sp. and Perna perna (Linnaeus, 1758 on upper and lower eulittoral bands, and by C. teedii and Ulva fasciata Delile, 1813 on the sub-littoral fringe. At Píer, the intertidal zone showed an even distribution, reflecting a less stressful environment. The differences on vertical distribution of the local benthic, particularly in the extent of the upper bands, indicate the variable conditions of wave exposure.

  16. Valobran Kaše: tijek i način izgradnje, primijenjene antičke tehnike gradnje u renesansi

    Directory of Open Access Journals (Sweden)

    Željko Peković

    2017-05-01

    Full Text Available Kaše breakwater, doubtless, is a remarkable monument of Renaissance civil engineering, masterly designed and executed by Paskoje Miličević. This boldly conceived project witnessed many problems from the very beginning of its construction. Serious damages due to heavy storms happened to be so severe at times that, as evidenced by archival data, the breakwater faced collapse, which called for emergency repairs. It was built in four stages between 1486 and 1514, in dry docks. The fi rst, smaller part was built in 1486, while the other, somewhat bigger, in 1487, to be joined in 1498, and expanded to the north in 1514. The breakwater was built in a submerged and later dried out dock (kašeta. The latter was framed with sheet piles (a layer of joint wooden posts, while the bottom consisted of two layers of bars upon which the breakwater is bedded. The breakwater was built from large stone blocks, joined by hydraulic mortar composed of red clay and lime, with no pozzolanic additives. Stone blocks were fi rst connected with iron and later bronze joints and clamps covered with lead. The central part of the breakwater is ‘cemented’ with lime mortar, red clay and sand, with an addition of crushed stone. Some ancient construction techniques, reinvented in the Renaissance, were applied in this building project. The reason why the breakwater still stands in place lies in two major facts: the use of large and high quality stone blocks and their connection, and in the section below the waterline, with metal joints and clamps covered with lead.

  17. Modelling of Sediment Transport in Beris Fishery Port

    Directory of Open Access Journals (Sweden)

    Samira Ardani

    2015-06-01

    Full Text Available In this paper, the large amount of sedimentation and the resultant shoreline advancements at the breakwaters of Beris Fishery Port are studied. A series of numerical modeling of waves, sediment transport, and shoreline changes were conducted to predict the complicated equilibrium shoreline. The outputs show that the nearshore directions of wave components are not perpendicular to the coast which reveals the existence of longshore currents and consequently sediment transport along the bay. Considering the dynamic equilibrium condition of the bay, the effect of the existing sediment resources in the studied area is also investigated. The study also shows that in spite of the change of the diffraction point of Beris Bay after the construction of the fishery port, the bay is approaching its dynamic equilibrium condition, and the shoreline advancement behind secondary breakwater will stop before blocking the entrance of the port. The probable solutions to overcome the sedimentation problem at the main breakwater are also discussed.

  18. Wave Forces on Crown Walls

    DEFF Research Database (Denmark)

    Pedersen, Jan; Burcharth, H. F.

    1993-01-01

    This paper presents some of the results from a large parametric laboratory study including more than 200 long-duration model tests. The study addresses both the wave forces imposed on the breakwater crown wall as well as the performance of the structure in reducing the wave overtopping. The testing...... programme includes variations of the sea state parameters and of the geometrical configuration of the breakwater and crown wall. Basic relations between forces/overtopping and the varied parameters are examined and preliminary design guidelines for structures within the tested range of variations...

  19. Description of Model Tests Carried Out by Aalborg University

    DEFF Research Database (Denmark)

    Frigaard, Peter; Schlütter, F.; Andersen, H.

    1996-01-01

    As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects.......As associated partner, Aalborg University (AU) have participated in different aspects of "the Zeebrugge project". AU has carried out an extensive number of small-scale model tests (1:65) with the Zeebrugge breakwater with the aim of investigating scale-effects....

  20. Zeebrugge Model

    DEFF Research Database (Denmark)

    Liu, Zhou; Frigaard, Peter

    This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University.......This report presents the model on wave run-up and run-down on the Zeebrugge breakwater under short-crested oblique wave attacks. The model test was performed in March-April 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University....

  1. A theory for the impact of a wave breaking onto a permeable barrier with jet generation

    OpenAIRE

    Cooker, MJ

    2013-01-01

    We model a water wave impact onto a porous breakwater. The breakwater surface is modelled as a thin barrier composed of solid matter pierced by channels through which water can flow freely. The water in the wave is modelled as a finite-length volume of inviscid, incompressible fluid in quasi-one-dimensional flow during its impact and flow through a typical hole in the barrier. The fluid volume moves at normal incidence to the barrier. After the initial impact the wave water starts to slow dow...

  2. A Case Study of Nearshore Wave Transformation Processes along the Coast of Mexico near the Laguna Verde Nuclear Power Plant Using a Fast Simulation Method

    Directory of Open Access Journals (Sweden)

    Israel-Enrique Herrera-Díaz

    2010-01-01

    numerical method was developed using a split proposed version of the mild-slope equation and solved by an implicit method in a finite volume grid; this technique easily allows model the wave effects caused by the breakwater building in coastal waters, where industrial and other economic activities take place. Controlled case studies have been made and the results match very well with the reference solution. The capability and utility of the model for real coastal areas are illustrated by application to the breakwater of the Laguna Verde Nuclear Power Plant (LVNPP.

  3. EPro Non-contact erosion profiling

    DEFF Research Database (Denmark)

    Meinert, Palle

    Pro is a profiling program build to measure the same surface or work piece multiple times and track changes due to erosion. It was developed during 2001 - 2002 at Aalborg University and was part of a Master of Science project dealing with stability of rubble mound breakwaters. The goal was to aut......Pro is a profiling program build to measure the same surface or work piece multiple times and track changes due to erosion. It was developed during 2001 - 2002 at Aalborg University and was part of a Master of Science project dealing with stability of rubble mound breakwaters. The goal...

  4. RESERCH STUDIES ON THE LOCATION OF A WAVE ENERGY POWER PLANT WITHIN CONSTANTA AREA

    Directory of Open Access Journals (Sweden)

    SAMOILESCU Gheorghe

    2015-05-01

    Full Text Available This paper is based on a research project on the development and installation of the first hydropneumatic plant in the Black Sea. It shows the location and its particularities, existing and previous hydrometeorological conditions, required work, plant qualities and standards to be met. The wave characteristics calculation and the hydrotechnic studies were presented: articulated concrete blocks demolition of the existing breakwater; dredging for the foundation of the plant; accomplish the foundation of the plant; installation of the plant; testing; consolidation and assuring protection of the breakwater; consolidation and assuring protection of the plant. Environmental protection measures are an important part of any research project of this type.

  5. Ceodouro project : overall design of an OWC in the new OPorto break water

    Energy Technology Data Exchange (ETDEWEB)

    Martins, E.; Carrilho, L. [EDP, Lisboa (Portugal); Neumann, F. [Centro de Energia das Ondas, Lisboa (Portugal); Ramos, F. Silveira [Consulmar, Lisboa (Portugal); Justino, Paulo Alexandre [INETI/DER, Lisboa, (Portugal); Gato, L.M.C. [Dep. de Engenharia Mecanica, IST, Lisboa, (Portugal); Trigo, L. [Kymaner, S. Domingos de Rana, (Portugal)

    2005-07-01

    The purpose of this work is to present and describe the design approach of the integration of an OWC wave energy plant in a caisson breakwater to be built at the Portuguese northern coast as a promising solution towards sustainable port structures. The presentation of different case study results by Neumann and Sarmento (2000) suggested that such a combination turns out to be a realistic alternative to the traditional coastal protection schemes. The large Portuguese engineering consulting company Consulmar, being responsible for a number of coastal and maritime engineering projects, has accepted the challenge of leading a project for an OWC integration in a caisson breakwater head in Northern Portugal. After the concession of the breakwater construction in 2004, a Consortium has proceeded with preliminary works concerning the integration of an OWC into the breakwater. The Portuguese companies Labelec (EDP group), Kymaner (mechanical components), EFACEC (electrical components) and the Institutions IPTM (Port and Maritime Institute), LNEC (Hydraulic Laboratory), INETI (National Laboratory), IST (University) and the WEC (Wave Energy Centre) are further contributors in the planning phase. This paper presents an overall description of the project, its steps and present state of development.

  6. A probabilistic approach to investigate the effect of wave chorology on process-based morphological modelling

    NARCIS (Netherlands)

    Dastgheib, A.; Rajabalinejad, M.R.; Ranasinghe, R.; Roelvink, D.

    2012-01-01

    This paper demonstrates the sensitivity of morphological process-based models to the chronology of input wave conditions. In this research the effect of an emerged offshore breakwater on the morphology of the beach is investigated. A 30 day long morphological simulation with real time history of the

  7. Wave Pressures on Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Kofoed, Jens Peter; Frigaard, Peter

    2006-01-01

    This paper presents results on loading action on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full- scale demonstration of robust a...

  8. New Formula for Stability of Cube Armoured Roundheads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2007-01-01

    Design of armour for rubble mound breakwater roundheads constitutes in many cases a problem due to the limitation of available data and guidelines. The objective of the paper is to present the results of a comprehensive model test study on the stability of cube armoured roundheads, resulting...

  9. Anatomical studies of timber and EPMA analysis of brass artefacts collected from steam engine shipwreck of Minicoy Island, Lakshadweep, India

    Digital Repository Service at National Institute of Oceanography (India)

    Tripati, S.; Shukla, S.R.; Som, V.; Sundaresh; Khedekar, V.; Shashikala, S.; Sharma, S.K.

    to rolling surf and the amidships and cabins were filled with water. Colombo formed a breakwater against the rolling waves, and the dis- tance between the ship and the land was short that women, children and the sick were dragged by the natives through...

  10. Role of grounded ship 'MV River Princess' in triggering erosion: A case study from Candolim Sinquerim Coast, Goa.

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.; Babu, M.T.; Sudhesh, K.; Mascarenhas, A.; Vethamony, P.

    to this grounded vessel. The results suggest that the orientation and length of the vessel and more importantly the direction of the waves prevailing over the region, have prompted the grounded ship behave like an offshore breakwater. Based on satellite imageries...

  11. Feasibility design of a floating airport and estimation of environmental forces on it; Futaishiki kuko no sekkei to kankyo gairyoku no suitei ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Tabeta, S.; Takei, Y. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-12-31

    A rough design was performed on a floating airport. On this floating structure, environmental external force was estimated, mooring design was carried out, and discussions was given on the position retaining performance important for airport functions and behavior of the floating structure. The discussion was given on cases that the airport is surrounded and not surrounded by floating breakwaters. A floating structure which becomes super-large in size requires considerations on force due to sea level gradient as a result of a tide. Deriving flow condition changes and force acting on the floating structure simultaneously by using numerical calculations makes it possible to estimate current force given with considerations on influence of the flow conditions created by installing the floating airport. Estimation was carried out by using a zone dividing method on wave drifting force acting upon the floating airport. As a result, it was found that installing floating and permeating type breakwaters can reduce the wave drifting force acting on the floating airport. The wave drifting force working on the floating airport can be reduced by installing the floating and permeating type breakwaters to lower levels than when no such breakwaters are installed. The airport may be moored with less number of fenders when the fenders of the same type are used. 18 refs., 10 figs., 5 tabs.

  12. Utilization of steel melting electric arc furnace slag for development ...

    Indian Academy of Sciences (India)

    Administrator

    Steel melting through electric arc furnace route is gaining popularity due to its many advantages, but generates a new waste, electric arc furnace slag, which is getting accumulated and land/mine filling and road construction are the only ... is a key factor, in such constructions as breakwater blocks, foundations, shoring walls, ...

  13. Computation of a coastal protection, using classical method, the PIANC-method or a full probabilistic approach ?

    NARCIS (Netherlands)

    Verhagen, H.J.

    2003-01-01

    In a classical design approach to breakwaters a design wave height is determined, and filled in into a design formula. Some undefined safety is added. In the method using partial safety coefficients (as developed by PIANC [1992] and recently also adopted by the Coastal Engineering Manual of the US

  14. Video monitoring of sandbar-shoreline response to an offshore submerged structure at a microtidal beach

    Science.gov (United States)

    Bouvier, Clément; Balouin, Yann; Castelle, Bruno

    2017-10-01

    In early 2013, an 800-m long and 12-m wide submerged breakwater with its crest in 2-m depth was implemented at the wave-dominated barred beach of Sète, SE France, to fight against erosion and submersion hazards. Daily video images from April 2011 to April 2016 covering an alongshore distance of 3.5 km are used to analyse the response of both the sandbar(s) and the shoreline to the structure implementation. Results show that the breakwater had a profound impact on the nearshore system, both shoreward of the structure and well away from it alongshore. A progressive rotation and linearisation of the sandbar was observed shoreward of the submerged breakwater. This resulted in the splitting of the sandbar adjacent to the structure during a net offshore sandbar migration event driven by a severe storm in December 2013. The typical formation of a salient or tombolo was not observed. Instead, shoreline coupled to the sandbar geometry, which resulted in a slight seaward migration of the shoreline in front of the structure. Overall, this study highlights that the role of the sandbar is critical to shoreline response to the implementation of breakwaters on barred beaches.

  15. 77 FR 26521 - Withdrawal of Notice of Intent To Prepare a Joint Draft Supplemental Environmental Impact...

    Science.gov (United States)

    2012-05-04

    ... address navigational safety and surge-related problems in Maalaea Harbor. Based on careful consideration... internal breakwater structures were investigated to address the navigational safety and surge-related...-initiated the project in 2009, with a focus on using stakeholder input and updated technical information to...

  16. Durability and Testing of Stone for use in Rubblemound structures

    DEFF Research Database (Denmark)

    Magoon, O.T.; Baird, W.F.; Ahrends, J.P.

    1993-01-01

    Rubblemound structures protected from wave action by a layer of quarried rock (stones) are the most common form of breakwaters. While extensive guidelines and procedures exist to select the size of stone there is very little information available on procedures to be followed to assure the quality...... of the in-place stone....

  17. The ideal flip-through impact: experimental and numerical investigation

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Hunt-Raby, A.; Jayaratne, R.

    2010-01-01

    Results from a physical experiment and a numerical computation are compared for a flip-through type wave impact on a vertical face, typical of a seawall or breakwater. The physical wave was generated by application of the focused-wave group technique to the amplitudes of a JONSWAP spectrum, with ...

  18. Implementing Engineering With Nature within the Corps: A Workshop

    Science.gov (United States)

    2013-09-01

    area for the Maasvlakte‐2 land reclamation, oyster reef stabilization of intertidal areas , sand import in the...for staying informed about what the USACE and others are doing in this area .  documenting projects and opportunities: The future of EWN... intertidal biodiversity on artificial shorelines: Mark Anthony Browne, University College Dublin 10:55 – 11:25 Breakwaters for the

  19. 78 FR 27196 - Modification of Permit Application and Intent for Additional Public Scoping for an Environmental...

    Science.gov (United States)

    2013-05-09

    ... Sound from the construction of wharfs, bulkheads, terminal facilities, container storage areas... construction of a breakwater of approximately 4,000 linear feet. The recently received permit application... be requested based on results of planned ship simulations. Final channel design and associated...

  20. Stage 2 Report for Reformulation Phase I General Design Memorandum, Cleveland Harbor, Ohio. Volume II. Appendices. Revision.

    Science.gov (United States)

    1983-02-01

    conditions inside the Lakefront Harbor with the spur breakwaters removed. 4. Ray then presented a slide show illustrating the evolution of the pro- posed...Asehelminthes Class Nematoda Alaimus sp. Dorylaimus sp. Mesodorylaimus sp. Phylum Annelida Class Polychaeta Manayunkia speciosa Class Oligochaeta. Aulodrilus

  1. Uncertainty related to Environmental Data and Estimated Extreme Events

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    The design loads on rubble mound breakwaters are almost entirely determined by the environmental conditions, i.e. sea state, water levels, sea bed characteristics, etc. It is the objective of sub-group B to identify the most important environmental parameters and evaluate the related uncertaintie...

  2. Probabilistic Design

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    This chapter describes how partial safety factors can be used in design of vertical wall breakwaters and an example of a code format is presented. The partial safety factors are calibrated on a probabilistic basis. The code calibration process used to calibrate some of the partial safety factors...

  3. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...... wave overtopping was studied as well....

  4. Coastal Changes due to the Construction of Artificial Harbour Entrances and Practical Solutions, including Beach Replenishment

    NARCIS (Netherlands)

    Bijker, E.W.; Van der Leijé, J.P.; Pilon, J.J.; Svasek, J.N.; In 't Veld, J.K.; Verhagen, H.J.

    1981-01-01

    When longshore sediment transport is interrupted by a construction along a coast, e.g harbour moles or a dredged approach channel, the equilibrium of the coastline may be disturbed. When the disruption is caused by breakwaters, the longshore transport that is held back will cause accretion updrift

  5. EPro user manual

    DEFF Research Database (Denmark)

    Meinert, Palle

    EPro is an Erosion PROfiling program, which was original, developed for the Hydraulics and Coastal Engineering group at Aalborg University. Its purpose was/is to make non-contact 3D-measurements of breakwaters, seabed etc. in order to determine erosion. The distances are measured by laser. All...

  6. Zeebrugge Model

    DEFF Research Database (Denmark)

    Jensen, Morten S.; Frigaard, Peter

    In the following, results from model tests with Zeebrugge breakwater are presented. The objective with these tests is partly to investigate the influence on wave run-up due to a changing waterlevel during a storm. Finally, the influence on wave run-up due to an introduced longshore current...

  7. Zeebrugge Model

    DEFF Research Database (Denmark)

    Sclütter, Flemming; Frigaard, Peter; Liu, Zhou

    This report presents the model test results on wave run-up on the Zeebrugge breakwater under the simulated prototype storms. The model test was performed in January 2000 at the Hydraulics & Coastal Engineering Laboratory, Aalborg University. The detailed description of the model is given...

  8. Stability of Armour Units in Oscillatory Flow

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Thompson, A. C.

    1983-01-01

    As part of a program to study the hydraulics of wave attack on rubble mound breakwaters tests were made on model armour units in a steady flow through a layer laid on a slope. The flow angle has little effect on stability for dolosse or rock layers. The head drop at failure across each type...

  9. Stability of Armour Units in Flow Through a Layer

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; C. Thompson, Alex

    1984-01-01

    As part of a program to study the hydraulics of wave attack on rubble mound breakwaters tests were made on model armour units in a steady flow through a layer laid on a slope. The flow angle has little effect on stability for dolosse or rock layers. The head drop at failure across each type...

  10. Temporal variability of macrofauna from a disturbed habitat in Zuari estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sivadas, S.; Ingole, B.S.; Nanajkar, M.

    ore berth and two multipurpose general cargo berths. A breakwater of 522.40 meters long protects the harbour from the SW monsoon. The harbour is dominated by periodic tidal exchange of oceanic and estuarine water (Cherian et al., 1974; Shetye et al...

  11. Transmisi dan Refleksi Gelombang pada Pemecah Gelombang Ambang Rendah Ganda Tumpukan Batu

    Directory of Open Access Journals (Sweden)

    Bambang Surendro

    2015-10-01

    Full Text Available Protection of beaches for tourism development, protection planning in addition to aiming to keep the damage to the beach will also need to think about the authenticity and beauty of the beach area . Building protective beaches that can meet these objectives include low threshold breakwaters (submerged breakwater. Some of the excessuse of low threshold breakwaters are: 1. No disturbing beauty of the beach; 2. because construction is under water, then when the wave comes partially absorbed wave energy, will be partially reflected, and the rest will be transmitted; 3. can become breeding grounds for fish, because the construction is hollow. The disadvantages are: 1. requires a large stone with a large number, 2. in the assembly requires a supporting infrastructure such as transport  equipment, long bridge, lifting equipment etc, thus requiring a lot of cost. Based on that research conducted by the title of the transmission and reflection of waves on double sumerged breakwater. Methodology of research, conducted with with physical models, and then continued with theoretical studies in order to obtain the equation for calculating the coefficient of wave  transmission and wave reflection coefficient. The results showed that to calculate the magnitude of the coefficient of wave transmission and wave reflection coefficient can be approximated by the following equation: , .

  12. Marine Structures with Extreme Overtopping Rates

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter

    2000-01-01

    In design of sea defence structures like seawalls, breakwaters and dikes, one of the main objectives is to minimize or even eliminate wave overtopping. For this reason numerous investigations have been performed over the past many years to determine the amount of overtopping occurring for typical...

  13. 3-D Hydraulic Model Testing of the New Roundhead in Suape, Brazil

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Sipavicius, A.

    This report deals with a three-dimensional model test study of the extension of the breakwater in Suape, Brazil. The roundhead was tested for stability in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given in this report...

  14. The Use of Gabbro Rock Armour in Rubble Mound Structures

    DEFF Research Database (Denmark)

    Beck, J. Blow; Burcharth, H. F.; Danielsen, S. W.

    2000-01-01

    Throughout several years Gabbro rocks have been used for various coast protective constructions and breakwaters at the North Sea Coast and in inner Danish waters. So far the use of Gabbro has been based solely on calculations from Shore Protection Manuals, i.e without model tests. Compared to ord...

  15. 78 FR 75249 - Safety Zone: Google's Night at Sea Fireworks Display, San Francisco Bay, Alameda, CA

    Science.gov (United States)

    2013-12-11

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone: Google's Night at Sea Fireworks Display... the breakwater in Alameda, CA in support of Google's Night at Sea Fireworks Displays on December 7.... Google will sponsor the Google's Night at Sea Fireworks Displays on December 7, 2013 and December 14...

  16. Measuring damage in physical model tests of rubble mounds

    NARCIS (Netherlands)

    Hofland, B.; Rosa-Santos, Paulo; Taveira-Pinto, Francisco; Lemos, Rute; Mendonça, A.; Juana Fortes, C

    2017-01-01

    This paper studies novel ways to evaluate armour damage in physical models of coastal structures. High-resolution damage data for reference rubble mound breakwaters obtained under the HYDRALAB+ joint-research project are analysed and discussed. These tests are used to analyse the way to describe

  17. Effects of exotic amphipod invasions on fish diet in the Lower Rhine

    NARCIS (Netherlands)

    Kelleher, B.; Bergers, P.J.M.; Brink, van den F.W.B.; Giller, P.S.; Velde, van der G.; Vaate, bij de B.

    1998-01-01

    To assess the importance and effect of recent exotic species invasions on components of food webs of common Lower Rhine biotopes (breakwaters and channel-connected sandpits), the diets of two important macrozoobenthivores, perch (Perca fluviatilis L.) and eel (Anguilla anguilla (L.)) were compared

  18. Stability of Cubipod Armoured Roundheads in Short Crested Waves

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Medina, Josep R.

    The roundhead is generally the most exposed part of the breakwater. Moreover, in case of rubble mound structures the needed armour size is larger than in the adjacent trunk. Typically units of almost double mass are needed in the roundhead if high density stones or concrete are not used in the head....

  19. 2 CFR 176.140 - Award term-Required Use of American Iron, Steel, and Manufactured Goods-Section 1605 of the...

    Science.gov (United States)

    2010-01-01

    ... 2009. When awarding Recovery Act funds for construction, alteration, maintenance, or repair of a public... construction site for incorporation into the building or work that has been— (i) Processed into a specific form..., docks, piers, wharves, ways, lighthouses, buoys, jetties, breakwaters, levees, and canals, and the...

  20. 29 CFR 3.2 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... part: (a) The terms building or work generally include construction activity as distinguished from..., docks, piers, wharves, ways, lighthouses, buoys, jetties, breakwaters, levees, and canals; dredging... building or work within the meaning of the regulations in this part. (b) The terms construction...

  1. Proceedings of the Meeting of the Coastal Engineering Research Board (43rd) Held at Vicksburg, Mississippi on 22-24 May 1985.

    Science.gov (United States)

    1985-08-01

    extensive renovation , as shown in Fig- ure 3. Total rehabilitation usually costs one-tenth to one-fourth as much as replacement with a new structure. 29...presented by Dr. Manuel da Silva, Ministerior Da Industria E Energia , Portugal. Dr. da Silva discussed the Sines breakwater failures of 1978 and 1979

  2. Cyclic Triaxial Tests on Eastern Scheldt Sand with Three Different Densities

    DEFF Research Database (Denmark)

    Jakobsen, Kim Parsberg

    This report contains the results of numerous cyclic triaxial tests performed within the framework of the project "Probabilistic Design Tools for Vertical Breakwaters (PROVERBS), MAST III". The performed tests constitute a part of an established data base to be used to estimate the undrained cycli...

  3. Modelling nourishments through the Durban piers: Research of sediment transport and surf conditions

    NARCIS (Netherlands)

    Bronsvoort, K.; Radermacher, M.; Van der Spek, B.J.; Spruit, R.; Van Tongeren, B.

    2011-01-01

    The Durban bight has a very dynamic and variable coastline which is constantly under attack by the Indian Ocean. To protect the Durban harbour from this energetic ocean, already in 1855 breakwaters have been constructed to protect the harbour and prevent sedimentation inside. The construction of

  4. An observation on the main factor for the high fatalities by the March 11 earthquake

    Science.gov (United States)

    Ishida, M.; Baba, T.; Ando, M.

    2011-12-01

    On 11 March 2011, Mw9.0 earthquake occurred in Tohoku district, the northeastern Japan, and caused a large tsunami which affected the greater part of the area. During 115 years prior to this event, large tsunamis have struck the Tohoku region in 1960, 1933 and 1896. Therefore, disaster mitigation efforts have been undertaken in the Tohoku region, such as the construction of incomparably strong breakwaters, the annual practice for tsunami evacuation drill, the preparation of hazard maps, etc. Despite these long-term efforts, ca. 25,000 deaths and missing persons were reported by the National Police Headquarters, Japan. In order to clarify the causes of such high number of the fatalities, we interviewed 120 tsunami survivors in 7 cities mainly in Iwate prefecture in several periods after the earthquake. Since the tsunami arrived more than 20-30 min later after the strong ground shaking stopped and highlands are within about 10 to 20 minutes on foot, residents would have been saved if people had taken an immediate action. We found several major reasons why the residents delayed their evacuation actions as follows: 1. Earthquakes that were forecast for the offshore Tohoku by the governmental committee had been much smaller than the March 11 event. Accordingly, evacuation shelters were located at the lower level than that required for the incoming tsunami; 2. The earthquake magnitude and tsunami height of the first warning issue by Japan Meteorological Agency (JMA) was significantly smaller than those of the actual events. Majority of local residents thought that breakwaters would protect them. The JMA renewed the earthquake magnitude and tsunami height step by step, but the corrected information did not reach to the local residents because of the blackout of electric power. Consequently, the residents were unable to get the renewed information through TV or radio; 3. Fifty percent of the local residents experienced the 1960 Chile tsunami that significantly smaller than

  5. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure, in...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs.......Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...

  6. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.

    2005-01-01

     Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure, i...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs....... Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...

  7. Hydraulic Characteristics of Seawave Slot-cone Generator Pilot Plant at Kvitsøy (Norway)

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Vicinanza, Diego; Kofoed, Jens Peter

    2007-01-01

    This paper presents results on wave overtopping and loading on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union FP6 priority 6.1 (Sustainable Energy System). The design of the structure consists of three reservoirs one on the top...... of each other to optimize the storage of potential energy in the overtopping water. The wave loadings on the main structure can be estimated using experiences from breakwater design, but the differences between the structures is so large that more reliable knowledge is needed. Model tests were carried out...... in a second phase the model has been adapted and equipped with pumps to measure the overtopping flow rates in the single reservoirs. The results of the tests highlight differences between 2D and 3D conditions in terms of pressures and hydraulic efficiency....

  8. Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Liu, Zhou; Howell, Gary L.

    1991-01-01

    Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... for structural integrity. The paper presents the results and the analyses of model tests with 200 kg and 200 g load-cell instrumented Dolosse. Static stresses and wave generated stresses were studied as well as model and scale effects. A preliminary design diagram for Dolosse is presented as well....

  9. Bivalves and Gastropods of the Gulf of Tehuantepec, Mexico: A Checklist of Species with Notes on Their Habitat and Local Distribution

    Directory of Open Access Journals (Sweden)

    Eduardo Ríos-Jara

    2009-01-01

    Full Text Available The taxonomic composition of 160 species of bivalves and gastropods recorded in the Gulf of Tehuantepec is presented with information on their habitat and distribution along 10 different localities of the shoreline and 42 stations of the continental shelf. The species were on sandy and rocky beaches, coastal lagoons, estuaries, mangroves, rocky breakwaters of ports, and shallow subtidal areas (14–47 m depth. A total of 78 bivalve species and 82 gastropod species were recorded. Most of these were associated with sandy and rocky beaches and breakwaters of ports. The estuaries host 30 species and the coastal lagoons only two. In the shallow subtidal there were 18 gastropod species and 40 bivalve species representing 36.3% of all. This study adds 24 bivalve species and 29 gastropod species not recorded in previous studies for a total count of 213 species (102 bivalves and 111 gastropods for Gulf of Tehuantepec.

  10. A Coupling Simulation Between Soil Scour and Seepage Flow by Using a Stabilized ISPH Method

    Directory of Open Access Journals (Sweden)

    Nogami Tomotaka

    2016-01-01

    Full Text Available In 2011, the example that breakwaters collapsed because of the basic ground’s destabilization was reported by Tohoku-Kanto earthquake tsunami. Fluid-Structure-Soil coupling simulation is desired for a systematic comprehension of the breakwater collapse mechanism, and it may help to develop next disaster prevention method. In this study, A particle simulation tool based on the SPH has been modified and improved to analyze seepage flow and soil scouring. In seepage flow analysis, as a first step, this simulation treat the surface flow and seepage flow interactions by using governing equation. In the scouring analysis, soil scour is judged by an empirical criteria based on quicksand quantity formula.

  11. The Identification of Land Subsidance by Levelling Measurement and GPR Data at Tanjung Emas Harbour, Semarang

    Directory of Open Access Journals (Sweden)

    Purnomo Raharjo

    2017-10-01

    Full Text Available Recently, the main problem in Semarang City is flood. This area has low relief that consists of coastal alluvial deposits, swamp and marine sediments. The coastline is characterized by muddy, sandy, and rocky coasts, and mangrove coast. Ground Penetrating Radar (GPR records, show that subsurface geological condition of northern part of Semarang is coastal alluvial deposit and in the south is volcanic rocks. The aims of this this research is to determine land subsidence by levelling measurement in 2005 in Tanjung Emas Harbour area built on 1995. During ten years, there are various land subsidance in this area: in Coaster Street (21 – 41 cm, container wharf (62 – 94 cm, north breakwater (64 – 79 cm, west breakwater (74 – 140 cm, east groin (76 – 89 cm, and stacking area ( 77 – 109 cm. According to this research, it is concluded that one reason causes of flooding in this area is land subsidence.

  12. Wave Interaction with Porous Coastal Structures

    DEFF Research Database (Denmark)

    Jensen, Bjarne

    . The present study seeks to extend the methods currently applied to gain more insight into the physical processes involved with armour layer destabilisation. Both experimental and numerical methods are treated. In Chapter 2 the flow and turbulence around armour layer stones as well as the shear stresses...... the contribution to generation of turbulence, and destabilizing shear stresses, from the wave breaking, the armour layer, and the porous core was singled out. In Chapter 3 a similar detailed approach was taken towards experimental investigation of the pressure induced forces in the filter layers below the main...... with the simulation of a rock toe structure on a rubble mound breakwater. The stones in the toe structure were resolved directly in the model while the rest of the breakwater was included with the porosity model. In Chapter 6 both experimental and numerical topics are included. The physical experiments includes...

  13. Scour around coastal structures

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Whiteouse, J. S.; Tørum, A.

    2001-01-01

    This paper summarizes the results of the European Union Marine Science and Technology (EU MAST) III project "Scour Around Coastal Structures" (SCARCOST). The summary is presented under three headings: (1) Introduction; (2) Flow and scour processes with the subheadings: flow and scour processes...... around vertical cylinders; flow and scour processes at detached breakwaters; flow and scour processes at submerged breakwaters; and the effect of turbulence on sediment transport; and (3) Sediment behaviour close to the structure with the subheadings: field measurement and analysis of wave-induced pore......) to calculate wave-induced pore pressures-the effect of liquefaction on sediment transport; penetration of blocks in non-consolidated fine soil, and cyclic stiffness of loose sand. The paper also includes a discussion of the role of scale effects in laboratory testing and the applicability of the results...

  14. Oluvil Port Development Project

    DEFF Research Database (Denmark)

    Frigaard, Peter; Margheritini, Lucia

    Oluvil Port Development Project is the first development of a large port infrastructure in the entire eastern coastline of Sri Lanka. The project is supported by the Danish Foreign Ministry. Feasibility studies and detailed design studies were carried out by Lanka Hydraulic Institute Ltd during...... the years 1995 to 2003. The design was reviewed by COWI a/s. Construction of the port was started in 2008. MT Højgaard a/s acted as contractor. The outer breakwaters were constructed as first part of the project. During and after completion of the breakwaters a serious beach erosion and sand accumulation...... has been observed. Severe erosion is seen north of the harbour and some accumulation of sand is seen south of the harbour. On a sandy coastline like the one in Oluvil such erosion problems as observed are very typical. The report: Oluvil Port Development Project: Studies on Beach Erosion written...

  15. Marine and Coastal Morphology: medium term and long-term area modelling

    DEFF Research Database (Denmark)

    Kristensen, Sten Esbjørn

    evolution model and apply them to problems concerning coastal protection strategies (both hard and soft measures). The applied coastal protection strategies involve morphological impact of detached shore parallel segmented breakwaters and shore normal impermeable groynes in groyne fields, and morphological...... solution has a two dimensional nature. 1.5D shoreline model A so-called “1.5D” implementation which introduces redistribution of sediment within a coastal profile in response to horizontal 2D currents makes it possible to simulate the morphological development in areas where 2D evolution occurs....... The 1.5D model is seen to produce reasonable results when subject to cases with detached breakwaters and groynes. The computational efficiency of the model is however reduced compared to the 1D model, because the increased freedom of the model reduces the maximum stable morphological time step. Bar...

  16. The SSG Wave Energy Converter

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Kofoed, Jens Peter

    2012-01-01

    The Sea-wave Slot-cone Generator concept (SSG) is a Wave Energy Converter based on the wave overtopping principle utilizing several reservoirs placed on top of each other, in which the energy of the incoming wave will be stored as potential energy. The water captured in the reservoirs will then run...... through turbines for electricity production. The system utilizes a wide spectrum of different wave conditions by means of multiple reservoirs, located at different levels above the still water level. Thereby, it obtains a high overall efficiency and it can be suitable for shoreline and breakwater...... at the Svaaheia site (Norway), Port of Hanstholm (Denmark) and Port of Garibaldi (Oregon, USA). In the last-mentioned two projects, the Sea-wave Slot-cone Generator technology is integrated into outer harbor breakwater and jetty reconstruction projects. Comprehensive studies have been performed in the last years...

  17. THESEUS Deliverable ID2.4

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Nørgaard, Jørgen Harck; Andersen, Thomas Lykke

    . The tested technologies are: - by reducing incident wave energy with a totally innovative solution, wave energy converters placed nearshore (WT 2.1, Part B), and with multi-purpose coastal defences characterised by low environmental impact, as artificial reefs (WT 2.2, Part C) and floating breakwaters (WT2.......4, Part E); - by increasing wave overtopping through an innovative dike reinforcement or by increasing wave overtopping resistance, through improved stability of dike inner slope and use of dike covering layers (WT 2.3, Part D); - by upgrading breakwater armour and crown elevation of existing defences...... to account for sea level rise (WT 2.5, Part F); The objectives of WP 2 are measurable and verifiable as the WP can show steady progression from innovative concepts through modelling to verified results. Based on the climate scenarios developed within WP 1, and on literature review, the WP progresses...

  18. Multiscale Simulation of Breaking Wave Impacts

    DEFF Research Database (Denmark)

    Lindberg, Ole

    The purpose of this project is to make an accurate, robust, geometric flexible and efficient model for calculation of forces on structures from nonlinear ocean waves and breaking wave impacts. Accurate prediction of the extreme forces on wind turbine foundations, breakwaters and tidal or wave power...... devises are important for enhancement structural designs. The proposed model is based on an incompressible and inviscid flow approximation and the governing equations are applied in an arbitrary Lagrangian-Eulerian moving frame of reference (ALE). The Runge-Kutta method (RK) is used for time integration...... compare reasonably well. The incompressible and inviscid ALE-WLS model is coupled with the potential flow model of Engsig-Karup et al. [2009], to perform multiscale calculation of breaking wave impacts on a vertical breakwater. The potential flow model provides accurate calculation of the wave...

  19. Distribution of Wave Loads for Design of Crown Walls in Deep and Shallow Water

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck; Andersen, Thomas Lykke

    2014-01-01

    This paper puts forward a new method to determine horizontal wave loads on rubble mound breakwater crown walls with specific exceedance probabilities based on the formulae by Nørgaard et al. (2013) as well as presents a new modified version of the wave run-up formula by Van der Meer & Stam (1992......). Predictions from the method are compared to measured horizontal wave loads from scaled model tests, and the new method provides results which are in agreement with measured values as long as the wave loads on the crown wall are relatively impulsive. Another aim of the paper has been to compare...... the displacements of a crown wall exposed to wave loads with different exceedance probabilities in an overload situation (in this case the loads exceeded by 0.1 % and 1/250 of the incident waves). The comparison is made using the assumption that the Eigenfrequency of the crown wall and breakwater is significantly...

  20. Hydrodynamic Conditions and Sediment Movement at Port of Port Orford

    Science.gov (United States)

    2015-05-15

    the Coastal Modeling System (CMS) (Sanchez et al. 2011; Lin et al. 2011) and the Particle Tracking Model ( PTM ) (MacDonald et al. 2006). The CMS and... PTM simulations by the CHL and NWP are conducted under various hydrodynamic and wave conditions, and different configurations of the breakwater...navigation channel. 122 18/03/2015 14 pp 3 Method CMS and PTM The flow and wave modeling for Port Orford is conducted using the CMS. The CMS is an

  1. Detection of decadal shoreline changes along Dhamara and Maipura coast, Odisha, India

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.; Dhiman, R.; Jayakumar, S.; Ilangovan, D.; Vethamony, P.

    activities in the area. Keywords: Remote sensing; Erosion; Accretion; Odisha coast; DSAS. 1. INTRODUCTION The coastline of India comprises of variety of habitats and ecosystems such as sandy and rocky beaches, cliffs, water and lagoons to bays.... These changes are attributed to construction of artificial barriers like breakwater, jetties, etc. (Nayak, 1992). The rising number of coastal disasters along the world’s coastlines throws light on the need for better and more efficient methodologies...

  2. Erosion Control of Scour during Construction; Report 3. Experimental Measurements of Refraction, Diffraction, and Current Patterns Near Jetties.

    Science.gov (United States)

    1980-09-01

    British Columbia, Canada. Blue, F. L., Jr., and Johnson, J. W. 1949 (Oct). "Diffraction of Water Waves Passing Through a Breakwater Gap," Transactions...Offshore Harbor," Technical Report No. 190, Massachusetts Institute of Technology , Cambridge, Mass. Dunham, J. W. 1951 (Oct). "Refraction and Diffraction...Engineers, Vol 104, No. WW2 , pp 119-133. Liu, P. L., and Lozano, C. J. 1979 (Mar). "Combined Wave Refraction and Diffraction," Proceedings, Coastal

  3. Capabilities of the Large-Scale Sediment Transport Facility

    Science.gov (United States)

    2016-04-01

    Facility by Ernest R. Smith, Duncan B. Bryant, and Anthony M. Priestas PURPOSE: This Coastal and Hydraulics Engineering Technical Note (CHETN...the facility. Figure 2. Experiments showing a tombolo forming leeward of a detached breakwater. Experiments examining the fate of nearshore placed...concluded that advancements in electronics and decreases in cost made it economically advantageous to buy new capacitance wave gauges. The Akamina AWP

  4. "The Way Ahead"

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    It is true for all structures that the design and the location affects the loads. Breakwaters are extreme examples of this thesis, since even small variations in waterdepth, orientation slope etc. produce large variations in the load. As the dominant load is stochastic in nature and exhibits extr...... basic knowledge. One could say that the available knowledge did not reach the engineers on time. One way ahead is, therefore, and always has been, to ensure good communication of up-to-date knowledge....

  5. Optimal Reliability-Based Code Calibration

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Kroon, I. B.; Faber, Michael Havbro

    1994-01-01

    Calibration of partial safety factors is considered in general, including classes of structures where no code exists beforehand. The partial safety factors are determined such that the difference between the reliability for the different structures in the class considered and a target reliability...... level is minimized. Code calibration on a decision theoretical basis is also considered and it is shown how target reliability indices can be calibrated. Results from code calibration for rubble mound breakwater designs are shown....

  6. Assessment of Modifications for Improving Navigation at Hilo Harbor, Hawaii

    Science.gov (United States)

    2016-06-01

    proposed modifications, (5) develop hydrodynamic conditions for the ship simulator study, and (6) document study results by a technical report. The...breakwater, and (f) developing hydrodynamic conditions for the ship simulator study. 1.3 Study area Hilo Harbor is a deep-draft port located in Hilo Bay...on the Island of Hawaii at the mouth of two rivers, the Wailuku River and the smaller Wailoa River. There is also a small- boat harbor in Radio Bay

  7. Stability for Structures Armored with Core-LocTM

    OpenAIRE

    ÇEVİK, Esin ÖZKAN; CİHAN, Kubilay; Yüksel, Yalçın

    2014-01-01

    In conventional two-layer systems various armor units such as tetrapod, dolos, and tribar have been commonly used. Recent developments are accropode and core-locTM, which can be used in a single layer of armoring. The units for one-layer systems have an interlocking response under waves and hence their stability is high. The structure slope, wave conditions and placement methods are other areas of interest related to the stability of breakwater armor units. This study was intended ...

  8. History of the Honolulu Engineer District 1905-1965

    Science.gov (United States)

    1970-01-30

    project of the same period was the removal of the Martha Davis, an American bark which burned and sank in HHo Harbor in May 1905, less than a...breakwater and dredging in the bay at HHo . The Nawiliwili Harbor project received its 16 first appropriation of $296,000 in fiscal year 1926 and the next...the completion of dredg- ing operations at Honolulu, HHo , Kahului, Nawili- wili, Port Allen, and Kaunakakai, each of the major islands were serviced

  9. Conceptual Regional Sediment Budget for USACE North Atlantic Division

    Science.gov (United States)

    2015-03-01

    breakwaters, or through beach nourishment . Virginia coastal cells are stable because of beach nourishment whereas the coastal cells along southern Maryland...to just north of Chincoteague have not had beach nourishment and are erosional. Cells were added as placeholders for reaches in which there were no...hospitals, emergency response facilities) and population density. Social vulnerability emphasizes older , younger, and lower-income populations

  10. Environmental Investigations and Analyses for Los Angeles-Long Beach Harbors, Los Angeles, California, 1973-1976.

    Science.gov (United States)

    1976-12-01

    Ealanus amphitrite Balanus amphitrite Boccardia proboscida** S Capitella capita ta* Cirrifarmia luxuriosa** *Elasmo pus rapax* Eumida sanguinea ** Halos...May 1 through May 18, 1973. PARULIDAE (Wood Warblers) vermivora celata ( Orange -crowned Warbler). Two seen on one day along the breakwater in early May... orange -crowned Warbler) Vireo gilvus (Warbling Vireo) hilsonia pusilla (Wilsons Warbler) 354. 0"~~ owe4 At"S 2% ’.e ’.e * -- ’... Chapter 9

  11. Low to high performance recycled cementitious materials: case studies

    OpenAIRE

    Etxeberria Larrañaga, Miren

    2015-01-01

    In this work, four real case studies using concrete produced with recycled aggregates are described. The four real cases carried out in Barcelona are: 1) Pavement filling with control low strength material (CLSM) employing fine recycled aggregates, 2) pervious recycled aggregate concrete employing coarse mixed recycled aggregates in the works undertaken at Cervantes park; 3) Concrete blocks produced employing recycled and slag aggregates as well as sea water for a new breakwater dyke and 4) R...

  12. Riparian Buffers for Runoff Control and Sensitive Species Habitat on U.S. Army Corps of Engineers Lake and Reservoir Projects

    Science.gov (United States)

    2016-10-01

    success and recruitment. Brown-headed Cowbirds (Molothrus ater Boddaert 1783), which lays eggs in the nests of flycatchers and other birds, also... eggs , which can result in viability failure. Habitat degradation and fragmentation ERDC WQTN-16-1 October 2016 5 has impacted the Yellow-billed...establish good root systems (Allan and Clark 1999). Geotextile rolls can be used as breakwaters, and they can also support planted vegetation (Allan

  13. Abu Dhabi’s New Urban Islands and Shorefront Development

    Directory of Open Access Journals (Sweden)

    El Amrousi Mohamed

    2017-01-01

    Full Text Available Abu Dhabi is in the process of urbanizing a group of Islands that surround its northern and eastern coastlines. Al-Lulu, Al-Saadiyat, Al- Maryah, Al-Reem and Yas Islands are all new urban enclaves that were desert islands and marshlands yet, have been developed over the past decade to urban islands that include epic and entertainment centres such as the Abu Dhabi Louvre, Guggenheim Museum, Ferrari World, NYU Abu Dhabi, the Paris Sorbonne Abu Dhabi in addition to iconic and exclusive waterfront residential units. These new islands re-brand the image of the main archipelago of Abu Dhabi that for decades retained a grid street pattern and pragmatic concrete blocks created in the late 1970s. The new urban islands transform Abu Dhabi’s image into a multinational modern Arab city seeking to become part of the global city network. Abu Dhabi’s new urban islands also act as breakwaters that protect the main archipelago’s coastline from erosion resulting from tidal change, because they are designed to include concrete and stone breakwater barriers. This paper represents a cross-disciplinary research between Civil Engineering and Architecture Departments in an attempt to explore the emerging infrastructure and urban expansion of Abu Dhabi from a multi-disciplinary perspective. We also highlight through simulating the effect of breakwaters on wave heights two scenarios for Al-Lulu Island the importance of these new barrier Islands on the urban expansion of Abu Dhabi.

  14. Influence of the Barrie de la Maza dock on the circulation pattern of the Ría of A Coruña (NW-Spain

    Directory of Open Access Journals (Sweden)

    Moncho Gómez-Gesteira

    2002-12-01

    Full Text Available A 3D hydrodynamical model is applied to the ria of A Coruña to analyze the evolution of the circulation pattern in the ria after the building of a breakwater (Barrie de la Maza dock in the sixties. This circulation pattern has changed greatly. On the one hand, the circulation, which was almost parallel to the shore line under the original conditions, now shows a gyre near the end of the dock. On the other hand, a considerable increase (about 30% in the velocities near the end of the breakwater and in the main channel of the estuary has been observed after the building of the dock. A stronger bottom shear stress has been generated in the estuary areas where the velocity increased. The bottom shear stress increase was particularly great (over 100% near the end of the dock. This increase in the shear stress produced bottom erosion and matter resuspension, and consequently major changes in the bathymetry. In addition, in situ sedimentary measurements carried out by Lopez-Jamar (1996 corroborate the bottom erosion in the main chanel of the estuary and at the end of the dock produced by the velocity increase generated by the building of the breakwater.

  15. EXPERIMENTAL STUDY OF WAVE FLOWS AROUND THE FINITE LENGTH VERTICAL WALL

    Directory of Open Access Journals (Sweden)

    Tran Long Giang

    2012-10-01

    Full Text Available Construction of breakwater structures of modern seaports requires computational models describing interaction of waves with structural elements of ports. The model should be based on numerical hydrodynamic models that contemplate all constituents of interaction between waves and structures, including those at various stages of construction. The above model makes it possible to have construction works performed in accordance with the pre-developed plan. Experimentalresearch of the behaviour of breakwater structures is to be conducted in laboratories. A scaled natural model is to be used for the above purpose to verify the model behaviour. The authors consider the methodology and results of experiments involving models of wave loads produced on vertical breakwater structures at various stages of their construction. On the basis of the experiments conducted by the authors, it is discovered that the value of the total wave force, that the vertical wall is exposed to, increases along with the wall length in the event of a constant wave mode, which is natural. However, the per-meter value of the wave force increases along with the increase in the length of the wall until it reaches the value of the length of a transverse obstacle divided by the length of waves equal to 0.28; thereafter, the wave force goes down. The authors assume that this phenomenon is caused by the change in the nature of interaction between waves and an obstacle and a transition from a diffraction-free flow to a diffraction flow. The authors believe that further researches are necessary to explore the phenomenon.

  16. Preliminary physics-engine model of dolosse interacting with one another

    CSIR Research Space (South Africa)

    Cooper, Antony K

    2008-03-01

    Full Text Available ://www.ageia.com/physx/index.html 2. Araki S & Deguchi I (2005), Numerical Simulation on 3-D Deformation of Submerged Rubble Mound Structure with DEM, International Coastal Symposium 2005, Hörn, Iceland. 3. Bierawski LG & Maeno S (2006), DEM-FEM Model of Highly Saturated Soil... Y, Higashira K and Kim T-M, “Computation of Composite Breakwater Deformation Modelled by Discrete Element Method”, International Coastal Symposium (ICS) 2005, p 222, Höfn, Iceland, 6-8 June 2005. http://www.itv.is/ics2005/Data/B5.4/Takayama...

  17. The Use of Numerical Modeling in the Planning of Physical Model Tests in a Multidirectional Wave Basin

    DEFF Research Database (Denmark)

    Carci, Enric; Rivero, Francisco J.; Burcharth, Hans Falk

    2003-01-01

    For the development of a new port of the A Coruña Port Authority, an extensive and careful analysis of wave propagation had to be done to determine design wave characteristics along the main breakwater, placed behind an irregular shoal. Preliminary numerical simulations showed that wave focusing...... improved the knowledge on the problem studied. Read More: http://www.worldscientific.com/doi/abs/10.1142/9789812791306_0042?prevSearch=The+Use+of+Numerical+Modeling+in+the+Planning+of+Physical+Model+Tests+in+a+Multidirectional+Wave+Basin&searchHistoryKey=...

  18. Erosion Control of Scour during Construction. Report 4. Stability of Underlayer Material Placed in Advance of Construction to Prevent Scour; Hydraulic Model Investigation.

    Science.gov (United States)

    1983-06-01

    raised .... Whenever a rock-mound breakwater is to be constructed on a soft bottom it is important first to place a layer of rock over the bottom for a...laerexen .0 twdl74 tprttp;nme fwae 4 lp IV~ ~ ~ mI 251 lae tikes2 tpr oye-wa-e et 6 f rtt~ ;wj pht 15 aeri al 20 toe l prototypiu we hegh 175 l protot...omm mmm eem mmtmemmm m *.~... .... . g. . . .. .m.. Still-Water Depth, ft iieme mimmemm iae lae mem em em ee .S~ . ~ *** . . me.... Model: 1.0 e. ee

  19. Coastal Erosion and Flooding Hazards on the North Sea Coast at Thyboron, Denmark

    DEFF Research Database (Denmark)

    Sørensen, Per; Sørensen, Carlo Sass; Nielsen, Peter

    Since a breach of the coastal barrier in 1862, the Thyboron Channel connecting the North Sea and the Lim Fiord has been artificially maintained by construction of breakwaters and groins on the North Sea coast and inside the channel, respectively. Sand nourishment schemes have since the 1980s coun...... counteracted the natural erosion in the upper profile on the North Sea coast where the alongshore sediment transport converges towards the channel and deposits up to 1 million m3/y on the flood tidal delta inside the fiord, Figure 1....

  20. A coupled soil-pore fluid formulation for modeling soil liquefaction and cyclic mobility in seabed using the finite volume method

    DEFF Research Database (Denmark)

    Tang, Tian; Roenby, Johan; Hededal, Ole

    The stability of offshore structures, such as wind turbine foundations, breakwaters, and immersed tunnels can be strongly affected by the liquefaction and cyclic mobility phenomena in the seabed. Our goal is to develop a numerical code for analysis of these situations. For this purpose, we start...... matrix solver, are discussed as well. Overall, investigations in this paper provide a methodology for developing a numerical code simulating liquefaction and cyclic mobility. In future work this will be implemented in practice with the aid of the open source CFD toolbox, OpenFOAM....

  1. Industry, Port, City (1879-1964). How Barranquilla took shape (Colombia)

    OpenAIRE

    Bell-Lemus, Carlos; Universidad del Atlántico

    2014-01-01

    The emergence of Barranquilla as Colombia’s most important maritime and fluvial port at the beginning of the 20thCentury was the result of the need for connecting the young republic to global markets. This process took place throughoutthe second half of the 19th Century and was consolidated with Bocas de Ceniza´s breakwater construction andended with the strengthening and supremacy of Buenaventura’s port, which became connected to the main exportdestination when the Panama Channel was complet...

  2. Design of Dolos Armour Units

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1993-01-01

    The slender, complex types of armour units, such as Tetrapods and Dolosse are widely used. Many of the recent failures are such rubble mound breakwaters revealed that there is an imbalance between strength (structural integrity) of the units and the hydraulic stability (resistance to displacements......) of the armour layers. The paper deals only with dolos armour and presents the first design diagrammes and formulae where stresses from static, quasistatic and impact loads are implemented as well as the hydraulic stability. The dolos is treated as a multi shape unit where the thickness can be adjusted...

  3. Wave Reflection in 3D Conditions

    DEFF Research Database (Denmark)

    Zanuttigh, Barbara; Andersen, Thomas Lykke

    2010-01-01

    Based on recent experiments carried out in wave basin on breakwaters with armour layer of rocks and cubes, this paper examines the dependence of the reflection coefficient on wave directional spreading and obliquity. Results suggest that long-crested and short-crested waves give similar reflection....... The reflection coefficient is markedly dependent on the wave angle of incidence. The performance of formulae available in the literature is checked against the new dataset and a significant improvement is proposed by including the wave obliquity factor that appears in the traditional expression...

  4. Special Foundation by means of reinforced-concrete caisson in Valencia Port; Cimentaciones especiales de los cajones del Muello Este. Puerto de Valencia

    Energy Technology Data Exchange (ETDEWEB)

    Gama Costa, P. M.

    2010-07-01

    This paper describes the process to construct a foundation by means of reinforced-concrete caisson on breakwaters. the project required to develop minimal dredging solutions as well as to improve the foundation areas of the what caissons. The improvement technique applied to the foundation area was based on gravel columns, since this solution was the most suitable for areas with high fine fraction contents, as it was the case. Gravel columns were executed following a bottom-feed method, and two different techniques: gravel tank top-feeding and gravel pumping. (Author)

  5. A rational methodology for the study of foundations for marine structures; Una metdologia racional para el estudio de cimentaciones de estructuras marinas

    Energy Technology Data Exchange (ETDEWEB)

    Mira Mc Willams, P.; Fernandez-Merodo, J. A.; Pastor Perez, M.; Monte Saez, J. L.; Martinez Santamaria, J. M.; Cuellar Mirasol, V.; Martin Baanante, M. E.; Rodriguez Sanchez-Arevalo, I; Lopez Maldonando, J. D.; Tomas Sampedro, A.

    2011-07-01

    A methodology for the study of marine foundations is presented. The response in displacements, stresses and pore water pressures in obtained from a finite element coupled formulation. Loads due to wave action of the foundation are obtained from a volume of fluid type fluid-structure interaction numerical model. Additionally, the methodology includes a Generalized Plasticity based constitutive model for granular materials capable of representing liquefaction fenomena of sands subjected to cyclic loading, such as those frequently appearing in the problems studied. Calibration of this model requires a series of laboratory tests detailed herein. This methodology is applied to the study of the response of a caisson breakwater foundation. (Author) 10 refs.

  6. The Application of Load-cell Technique in the Study of Armour Unit Responses to Impact Loads Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1995-01-01

    The slender, complex types of armour units, such as Tetrapods and Dolosse are widely used for rubble mound breakwaters. Many of the recent failures of such structures were caused by unforeseen early breakage of the units, thus revealing an in balance between the strength (structural integrity......) of the units and the hydraulic stability (resistance to displacements) of the armour layers. Breakage is caused by stresses from static, pulsating and impact loads. Impact load generated stresses are difficult to investigate due to non-linear scaling laws. The paper describes a method by which impact loads on...

  7. Regeneración del frente litoral del Marenyet. Término municipal Cullera (Valencia)

    OpenAIRE

    ALBIÑANA BARRA, MIGUEL

    2016-01-01

    [EN] Regeneration of the coast front of Marenyet in the municipality of Cullera (Valencia). Consists of three submerged breakwaters and artificial feeding. [CAT] Regeneració del front litoral del Marenyet al terme municipal de Cullera (València). Constituït per tres dics exempts submergit i una alimentació artificial. [ES] Regeneración del frente litoral del Marenyet en el término municipal de Cullera (Valencia). Constituido por tres diques exentos sumergido y una alimentación artificia...

  8. Spatial Distribution of Wave Pressures on Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Frigaard, Peter

    2009-01-01

    This paper presents results on loading acting on an innovative caisson breakwater for electricity production. The work reported here is part of the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full-scale demonstration of robust and high......-efficiency wave energy converter" (WAVESSG). Information on wave loadings acting on Wave Energy Convert (WEC) Seawave Slot-Cone Generator (SSG) exposed to extreme wave conditions are reported. The SSG concept is based on the principle of overtopping and storing the wave energy in several reservoirs placed one...

  9. A General Discussion of Problems Related to the Determination of Concrete Armour Unit Stresses Including Specific Results related to Static and Dynamic Stresses in Dolosse

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1989-01-01

    Recent breakwater failures revealed the shortcomings of the traditional design procedures for concrete armour units. This paper deals with one of them, which can be expressed as the "lack of balance between the hydraulic stability of the armour layer and the mechanical strength or integrity...... of the units". This problem is related mainly to the slender types of armour units. The paper discusses the various types of loads, and the practical determination of the wave and gravity induced loads and stresses, especially the model test technique and its restrictions. Examples related to Dolosse...

  10. Interviewing insights regarding the fatalities inflicted by the 2011 Great East Japan Earthquake

    Directory of Open Access Journals (Sweden)

    M. Ando

    2013-09-01

    Full Text Available One hundred fifty survivors of the 11 March 2011 Great East Japan Earthquake (Tohoku-oki earthquake (Mw = 9.0 were interviewed to study the causes of deaths from the associated tsunami in coastal areas of Tohoku. The first official tsunami warning underestimated the height of the tsunami and 40% of the interviewees did not obtain this warning due to immediate blackouts and a lack of communication after the earthquake. Many chose to remain in dangerous locations based on the underestimated warning and their experiences with previous smaller tsunamis and/or due to misunderstanding the mitigating effects of nearby breakwaters in blocking incoming tsunamis. Some delayed their evacuation to perform family safety checks, and in many situations, the people affected misunderstood the risks involved in tsunamis. In this area, three large tsunamis have struck in the 115 yr preceding the 2011 tsunami. These tsunamis remained in the collective memory of communities, and numerous measures against future tsunami damage, such as breakwaters and tsunami evacuation drills, had been implemented. Despite these preparedness efforts, approximately 18 500 deaths and cases of missing persons occurred. The death rate with the age of 65 and above was particularly high, four times higher than that with other age groups. These interviews indicate that deaths resulted from a variety of reasons, but if residents had taken immediate action after the major ground motion stopped, most residents might have been saved. Education about the science behind earthquakes and tsunamis could help save more lives in the future.

  11. Analysis on the Effects of Flood Damage Mitigation in Coastal City according to Coastal Structure Construction : focusing on Busan-Si Marin City in South Korea

    Science.gov (United States)

    Youngseok, Song; Moojong, Park

    2017-04-01

    Recently, as sea level rise and rainfall increase due to climate change, Urban development in the coastal area has caused multiple flood damages in coastal cities with a mixture flood mitigation as well as wave overtopping. flood damage of coastal floods that occur continuously in the coastal area is the main cause of flood mitigation rather than wave overtopping when a typhoon occurs. coastal structures that can reduce the flood damage of coastal cities due to wave overtopping include breakwaters and tetraport located near the coast. but, tetraport are facilities to reduce the impact of waves, it is not a facility to reduce flood damage. in this study, the reduction effects of depending on flood damage area and expected damages cost before and after installation of breakwaters were analyzed for Marine City located on the coast of Busan Acknowledgement This research was supported by a grant [MPSS-NH-2015-77] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

  12. Desing and construction of caissons for wave activated power generation at Haramachi thermal power plant; Haramachi karyoku hatsudensho haryoku hatsuden`yo keson no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M.; Saski, A.; Otaka, M. [Tohoku Electric Power Co. Ltd., Sendai (Japan)

    1995-11-05

    At the Haramachi thermal power plant, demonstration tests are planned for the water valve intensive wave activated power generation system which utilizes a part of the caisson composite breakwater of the south breakwater. Power is generated by combining a 130KW rated output power generating system to the caisson for wave activated generation, and power is sent to a 6KV power system to collect and analyze the basic data in actual sea area, verify the efficiency of each member, verify the rectification effect of water valves, and verify power generation and as system interconnection characteristics. A report is made on the establishment of the basic form of the wave force caisson, design method, result of hydraulic model test, fabricating method, and the processes. The fabrication of the wave force caisson started in 1994, and completed with the fabrication made on land and on sea. The construction joint of two wave force caissons on the sea has been completed and cured on a temporary placing mound, and compaction of the wave force caisson foundation mound is now underway. The installation is scheduled to start in November, 1995, and the verification test is expected to be made from 1996. 4 refs., 18 figs., 4 tabs.

  13. Cube or block. Statistical analysis, historial review, failure mode and behaviour; Cubo o bloque. Ajuste estadistico, analisis historico, modo de fallo y comportamiento

    Energy Technology Data Exchange (ETDEWEB)

    Negro, V.; Varela, O.; Campo, J. M. del; Lopez Gutierrez, J. S.

    2010-07-01

    Many different concrete shapes have been developed as armour units for rubble mound breakwaters. Nearly all are mass concrete construction and can be classified as random placed or regular patterns Placed. the majority of artificial armour unit are placed in two layers and they are massive. they intended to function in a similar way to natural rock (cubes, blocks, antifer cubes,...). More complex armour units were designed to achieve greater stability by obtaining a high degree of interlock (dolosse, accropode, Xbloc, core-loc,...). finally, the third group are the regular pattern placed units with a greater percentage of voids for giving a stronger dissipation of cement hydration (cob, shed, hollow cubes,...), This research deals about the comparison between two massive concrete units, the cubes and the blocks and the analysis of the geometry, the porosity, the construction process and the failure mode. The first stage is the statistical analysis. the scope of it is based on the historical reference of the Spanish Breakwaters with main layer of cubes and blocks (ministry of Public Works, General Directorate of Ports, 1988). (Author) 9 refs.

  14. Wave Energy Exploitation System Integrated in the Coastal Structure of a Mediterranean Port

    Directory of Open Access Journals (Sweden)

    Stefania Naty

    2016-12-01

    Full Text Available A feasibility study for installing Wave Energy Converters (WECs in a Mediterranean port is presented here. The final aim is to evaluate the possibility of building a green touristic infrastructure in a site having ordinary wave energy. In particular, the site of interest is Giardini Naxos, which is located in the northern Ionian coast of the island of Sicily (Italy. A preliminary estimation of the available energy has been carried out. The chosen type of WEC device is the Oscillating Water Column (OWC system, which is found here to allow for good integration with the vertical breakwater needed for the extension of the existing port. Its feasibility is evaluated from the structural and economic point of view. Towards this aim, the system is tested in the laboratory for estimating the reflection coefficients and the pressures on the structure, which allow us to carry out the optimization of the OWC breakwater. Furthermore, the air turbine noise is estimated and an attenuation chamber is designed to reduce such noise to within acceptable levels. The economic feasibility study allows for an evaluation of the recuperation period of the investment, which is slightly less than the service life of the WEC device.

  15. Shore Protection for a Placer Deposit Rich Beach of the Southwest Coast of India

    Directory of Open Access Journals (Sweden)

    L. Sheela Nair

    2013-03-01

    Full Text Available The placer deposits dominated Neendakara-Kayamkulam sector along the Kerala coast on the southwest coast of India may be characterized as a dynamic, unstable beach based on shoreline oscillations observed over the past years. Both long-term and short-term shoreline variations can be easily linked directly to a number of factors – both natural and anthropogenic. Of these, activities such as large scale mining for heavy minerals; dredging and construction of hard structures such as breakwaters and groins; have contributed significantly to the changes in shoreline. The coastal hydrodynamics of the area is highly complex because of the variation in shoreline orientation and near shore slope. The present work is an attempt to understand the coastal processes and to identify the factors responsible for the shoreline oscillations by conducting numerical model studies. The studies on the shoreline changes are also carried out as a part of this study in order to identify the critical areas of the shore that need immediate protection. The study shows that the northern part of the study area (barring the 2km stretch lying to the immediate south of the Kayamkulam inlet has been eroding significantly which requires immediate protection. The proposed shoreline protection measure is to provide detached offshore submerged breakwaters.

  16. The SSG Wave Energy Converter: Performance, Status and Recent Developments

    Directory of Open Access Journals (Sweden)

    Mariano Buccino

    2012-01-01

    Full Text Available The Sea-wave Slot-cone Generator (SSG is a Wave Energy Converter based on the wave overtopping principle; it employs several reservoirs placed on top of each other, in which the energy of incoming waves is stored as potential energy. Then, the captured water runs through turbines for electricity production. The system works under a wide spectrum of different wave conditions, giving a high overall efficiency. It can be suitable for shoreline and breakwater applications and presents particular advantages, such as sharing structure costs, availability of grid connection and recirculation of water inside the harbor, as the outlet of the turbines is on the rear part of the system. Recently, plans for the SSG pilot installations are in progress at the Svaaheia site (Norway, the port of Hanstholm (Denmark and the port of Garibaldi (Oregon, USA. In the last-mentioned two projects, the Sea-wave Slot-cone Generator technology is integrated into the outer harbor breakwater and jetty reconstruction projects. In the last years extensive studies have been performed on the hydraulic and the structural response of this converter, with the aim of optimizing the design process. The investigations have been conducted by physical model tests and numerical simulations and many results have been published on both conference proceedings and journals. The main scope of this paper is reviewing the most significant findings, to provide the reader with an organic overview on the present status of knowledge.

  17. Biorock Electric Reefs Grow Back Severely Eroded Beaches in Months

    Directory of Open Access Journals (Sweden)

    Thomas J. F. Goreau

    2017-10-01

    Full Text Available Severely eroded beaches on low lying islands in Indonesia were grown back in a few months—believed to be a record—using an innovative method of shore protection, Biorock electric reef technology. Biorock shore protection reefs are growing limestone structures that get stronger with age and repair themselves, are cheaper than concrete or rock sea walls and breakwaters, and are much more effective at shore protection and beach growth. Biorock reefs are permeable, porous, growing, self-repairing structures of any size or shape, which dissipate wave energy by internal refraction, diffraction, and frictional dissipation. They do not cause reflection of waves like hard sea walls and breakwaters, which erodes the sand in front of, and then underneath, such structures, until they collapse. Biorock reefs stimulate settlement, growth, survival, and resistance to the environmental stress of all forms of marine life, restoring coral reefs, sea grasses, biological sand production, and fisheries habitat. Biorock reefs can grow back eroded beaches and islands faster than the rate of sea level rise, and are the most cost-effective method of shore protection and adaptation to global sea level rise for low lying islands and coasts.

  18. Mineral accretion technology for coral reef restoration, shore protection, and adaptation to rising sea level

    Energy Technology Data Exchange (ETDEWEB)

    Goreau, T.J.; Hilbertz, W. [Global Coral Reef Alliance, Chappaqua, NY (United States)

    1997-12-31

    Electrolysis of seawater is used to precipitate limestone on top of underwater steel structures to create growing artificial reefs to enhance coral growth, restore coral reef habitat, provide shelter for fish, shellfish, and other marine organisms, generate white sand for beach replenishment, and protect shore lines from wave erosion. Films and slides will be shown of existing structures in Jamaica, Panama, and the Maldives, and projects being developed in these and other locations will be evaluated. The method is unique because it creates the only artificial reef structures that generate the natural limestone substrate from which corals and coral reefs are composed, speeding the settlement and growth of calcareous organisms, and attracting the full range of other reef organisms. The structures are self-repairing and grow stronger with age. Power sources utilized include batteries, battery chargers, photovoltaic panels, and windmills. The cost of seawalls and breakwaters produced by this method is less than one tenth that of conventional technology. Because the technology is readily scaled up to build breakwaters and artificial islands able to keep pace with rising sea level it is capable of playing an important role in protecting low lying coastal areas from the effects of global climate change.

  19. Changes in the physical characteristics of the water column at the mouth of a torrent during an extreme rainfall event

    Science.gov (United States)

    Capello, Marco; Cutroneo, Laura; Ferretti, Gabriele; Gallino, Stefano; Canepa, Giuseppe

    2016-10-01

    The city of Genoa (Italy) was hit by a severe flash flood on the 4th November, 2011. The effects of this event on the water column at the mouth of the Polcevera Torrent, the main water course flowing into the Port of Genoa, are presented in this paper. The hydrological characteristics were measured with two conductivity-temperature-depth probes equipped with a turbidimeter, one fixed on the port breakwater and one used at mobile stations around the mouth of the torrent. The dynamics were measured with a horizontal acoustic Doppler current profiler (H-ADCP) fixed on the breakwater. Data collected before, during and after the flash flood were analysed to quantify the changes due to the event. The weather conditions during the event showed extremely heavy rain associated with strong weather instability, the convergence of a low-level southerly flow and the persistence of a squall line over a restricted area. The temperature, salinity, turbidity and dissolved oxygen measurements taken during the event showed the strong influence of the weather conditions and the fresh water input of the torrent itself on the water column at its mouth, an influence that dissipated during the following days. Instead, the dynamics measured at the mouth of the torrent were affected more by the strong south-easterly wind and the sea than the flow of fresh water.

  20. What caused a large number of fatalities in the Tohoku earthquake?

    Science.gov (United States)

    Ando, M.; Ishida, M.; Nishikawa, Y.; Mizuki, C.; Hayashi, Y.

    2012-04-01

    The Mw9.0 earthquake caused 20,000 deaths and missing persons in northeastern Japan. 115 years prior to this event, there were three historical tsunamis that struck the region, one of which is a "tsunami earthquake" resulted with a death toll of 22,000. Since then, numerous breakwaters were constructed along the entire northeastern coasts and tsunami evacuation drills were carried out and hazard maps were distributed to local residents on numerous communities. However, despite the constructions and preparedness efforts, the March 11 Tohoku earthquake caused numerous fatalities. The strong shaking lasted three minutes or longer, thus all residents recognized that this is the strongest and longest earthquake that they had been ever experienced in their lives. The tsunami inundated an enormous area at about 560km2 over 35 cities along the coast of northeast Japan. To find out the reasons behind the high number of fatalities due to the March 11 tsunami, we interviewed 150 tsunami survivors at public evacuation shelters in 7 cities mainly in Iwate prefecture in mid-April and early June 2011. Interviews were done for about 30min or longer focused on their evacuation behaviors and those that they had observed. On the basis of the interviews, we found that residents' decisions not to evacuate immediately were partly due to or influenced by earthquake science results. Below are some of the factors that affected residents' decisions. 1. Earthquake hazard assessments turned out to be incorrect. Expected earthquake magnitudes and resultant hazards in northeastern Japan assessed and publicized by the government were significantly smaller than the actual Tohoku earthquake. 2. Many residents did not receive accurate tsunami warnings. The first tsunami warning were too small compared with the actual tsunami heights. 3. The previous frequent warnings with overestimated tsunami height influenced the behavior of the residents. 4. Many local residents above 55 years old experienced

  1. Development of High Precision Tsunami Runup Calculation Method Coupled with Structure Analysis

    Science.gov (United States)

    Arikawa, Taro; Seki, Katsumi; Chida, Yu; Takagawa, Tomohiro; Shimosako, Kenichiro

    2017-04-01

    The 2011 Great East Japan Earthquake (GEJE) has shown that tsunami disasters are not limited to inundation damage in a specified region, but may destroy a wide area, causing a major disaster. Evaluating standing land structures and damage to them requires highly precise evaluation of three-dimensional fluid motion - an expensive process. Our research goals were thus to develop a coupling STOC-CADMAS (Arikawa and Tomita, 2016) coupling with the structure analysis (Arikawa et. al., 2009) to efficiently calculate all stages from tsunami source to runup including the deformation of structures and to verify their applicability. We also investigated the stability of breakwaters at Kamaishi Bay. Fig. 1 shows the whole of this calculation system. The STOC-ML simulator approximates pressure by hydrostatic pressure and calculates the wave profiles based on an equation of continuity, thereby lowering calculation cost, primarily calculating from a e epi center to the shallow region. As a simulator, STOC-IC solves pressure based on a Poisson equation to account for a shallower, more complex topography, but reduces computation cost slightly to calculate the area near a port by setting the water surface based on an equation of continuity. CS3D also solves a Navier-Stokes equation and sets the water surface by VOF to deal with the runup area, with its complex surfaces of overflows and bores. STR solves the structure analysis including the geo analysis based on the Biot's formula. By coupling these, it efficiently calculates the tsunami profile from the propagation to the inundation. The numerical results compared with the physical experiments done by Arikawa et. al.,2012. It was good agreement with the experimental ones. Finally, the system applied to the local situation at Kamaishi bay. The almost breakwaters were washed away, whose situation was similar to the damage at Kamaishi bay. REFERENCES T. Arikawa and T. Tomita (2016): "Development of High Precision Tsunami Runup

  2. Modelling of Tsunami Flow and Impact in Inundation Zone, Case Study for 2011 Great East Japan Tsunami

    Science.gov (United States)

    Ozer, C.; Yalciner, A. C.; Zaytsev, A.

    2011-12-01

    It has been clarified by 2004 Indian Ocean and 2001 Great East Japan tsunami events that the major reasons of impacts and damage of tsunamis depend on the flow parameters in nearshore and inundation zone. Hence the determination of impact level or tsunami drag force becomes essential. The square of Froude number (Fr2) which depends on the relation between current velocity and flow depth at any instant and any location is one of the effective parameters that represents the level of drag force exerted by the flow. Current velocity and flow depth change spatially and instantaneously in inundation zone. Therefore, maximum values of Fr2 occur in relation to the instantaneous values of current and flow depth. In this study, a series of fine grid simulations of tsunami inundation are performed using the numerical code NAMI DANCE which is modified in the frame of Joint Research Project MORAT between Russia and Turkey. A study domain having 1:20 beach slope is selected. At the coastal area, specially arranged rectangular coastal structures are located. The coastal area is selected as unprotected or protected by a seawall with different heights and/or a breakwater. The maximum values of Fr2 are computed at each grid node during the simulations of different incoming tsunami amplitudes. Furthermore the current velocities and flow depth at the time of maximum Fr2 are also computed. The spatial changes of these parameters along the lines perpendicular to the shore are plotted and the results are compared. A scale of Fr2 values for the assessment of the spatial change of damage level is developed. Damage level is also evaluated and discussed considering i) the presence of the coastal protection structures (i.e. tsunami walls etc.), ii) the presence of breakwaters, iii) the layout of the structures and roads, iv) type of the structures (R/C, timber, half-timbered, truss etc). The results are used to discuss the coastal damage by 2011 Japan tsunami event. In the case study, the

  3. Optimization of power take-off equipment for an oscillating water column wave energy plant

    Energy Technology Data Exchange (ETDEWEB)

    Gato, L.M.C.; Falcao, Antonio de F.O. [Dept. de Engenharia Mecanica do IST, Lisboa (Portugal); Paulo Alexandre Justino [INETI/DER, Lisboa (Portugal)

    2005-07-01

    The paper reports the optimization study of the electro-mechanical power take-off equipment for the OWC plant whose structure is a caisson forming the head of the new Douro breakwater. The stochastic approach is employed to model the wave-to-wire energy conversion. The optimization includes rotational speed (for each sea state), turbine geometry and size, and generator rated power. The procedure is implemented into a fully integrated computer code, that yields numerical results for the multi-variable optimization process and for the electrical power output (annual average and for different sea states) with modest computing time (much less than if a time-domain model were used instead). Although focused into a particular real case, the paper is intended to outline a design method that can be applied to a wider class of wave energy converters.

  4. Numerical prediction of the natural frequency of an Oscillating Water Column operating under resonant conditions

    Directory of Open Access Journals (Sweden)

    Marco Torresi

    2016-12-01

    Full Text Available Among the different technologies developed in order to harness wave energy, the Oscillating Water Column devices are the most accredited for an actual diffusion. Recently, Boccotti has patented the REWEC1 (REsonant sea Wave Energy Converter solution 1, a submerged breakwater that performs an active coast protection, embedding an Oscillating Water Column device, which is capable of operating under resonant conditions with that sea state, which gives the highest yearly energy contribution. The REWEC1 dynamic behavior can be approximated by means of a mass-spring-damper system. According to this approximation, a criterion for evaluating the oscillating natural frequency of the REWEC1 has been derived. This criterion has been validated against both experimental results and computational fluid dynamics simulations, performed on a REWEC1 laboratory-scale model. The numerical simulations have shown a good agreement between measurements and predictions.

  5. Design, Construction, Reliability and Hydraulic Performance of an Innovative Wave Overtopping Device

    DEFF Research Database (Denmark)

    Frigaard, Peter; Andersen, Thomas Lykke; Margheritini, Lucia

    2008-01-01

    The SSG (Sea Slot-cone Generator) is a wave energy converter of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level, in which the water of incoming waves is stored temporary. In each reservoir, expressively designed low...... head hydroturbines are converting the potential energy of the stored water into power. A yearly energy production of 320 MWh is foreseen for a 10 meter wide section. A key to success for the SSG will be the low cost of the structure and its robustness. During the last 2 years such a 1350 tonnes...... is that some breakwaters under design are being investigated as a possible places for integrating the SSG structure. The paper describes the concept of the SSG wave energy converter, the structure and the studies that led to its design....

  6. Stability of Cubipod Armoured Roundheads in Short Crested Waves

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Medina, Josep R.

    2011-01-01

    The paper presents a comparison of the stability of concrete cube armour and Cubipod armour in a breakwater roundhead with slope 1:1.5, exposed to both 2-D (long-crested) and 3-D (short-crested) waves. The model tests were performed at the Hydraulics and Coastal Engineering Laboratory at Aalborg...... University, Denmark. The model tests showed that Cubipod armour is more stable than cube armour when exposed to longer waves (steepness approx. 0.025) and has equal stability to cubes in shorter waves. The Cubipod armour layer contained due to its high porosity approximately 6-17% less concrete than the cube...... armour layer. Therefore, it was concluded that per used volume of concrete the Cubipods perform better than the cubes....

  7. Numerical simulation of wave-induced currents combined with parabolic mild-slope equation in curvilinear coordinates

    Science.gov (United States)

    Cui, Lei; Tong, Fei-Fei; Shi, Feng

    2011-09-01

    Researches on breaking-induced currents by waves are summarized firstly in this paper. Then, a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline. The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation. The wave module actually serves as the driving force to provide the current module with required radiation stresses. The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module, respectively. The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater. The numerical results are compared with the measured data and published numerical results.

  8. On the Degradation of Concrete in Marine Structures

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Hofman Frisch, P.; Freisleben, P.

    1985-01-01

    Concrete is a cheap and extremely handy material and as such used extensively also in marine structures. Everybody dealing with this material knows examples of concrete apparently of almost infinite durability but also examples where serious degradation started shortly after completion...... of the structure. It is a fact that despite the tremendous amount of research and despite the material having been used for generations, the difference between success and failure is still small. The paper is in three parts. In the first part, which deals with concrete in breakwater structures, the conventional...... practice and inherent problems are dealt with. Some recommendations on concrete specifications and production technique are also presented. The second part of the paper presents conventional concrete problems as observed in quaywall structures in harbour basins. On the background of the first two parts...

  9. Key Aspects of Wave Energy

    DEFF Research Database (Denmark)

    Margheritini, Lucia; Nørgaard, Jørgen Harck

    2012-01-01

    Diversification of renewable energy sources is fundamental to ensure sustainability. In this contest, wave energy can provide a substantial contribution as soon as the sector breaks into the market. In order to accelerate shift from a technology to a market focus and reduce technical and non...... be used as a breakwater therefore providing a solid structure for harbor protection; the Wave Star can be used as a base for offshore wind and photovoltaic installation in the middle of the sea, realizing an hybrid renewable energy platform. It is the authors´ believe that taking wave energy devices......-technical risks, it is critical to provide comprehensive and reliable information on the technologies without neglecting attractive advantages. It is possible to underline a different key of lecture of wave energy performance by considering efficiency and power production as well as device versatility...

  10. Predictive model for wave-induced currents and 3D beach evolution based on FAVOR Method

    Directory of Open Access Journals (Sweden)

    Masamitsu Kuroiwa

    2010-06-01

    Full Text Available The development of a numerical model using the fractional area/volume obstacle representation (FAVOR method for predicting a nearshore current field bounded by complicated geometric shapes, and a three-dimensional (3D beach evolution was described in this article. The 3D model was first tested against three cases to simulate the nearshore current fields around coastal structures, a river mouth, and a large scale cusp bathymetry. Then, the morphodynamic model tests, which are adopting the nearshore current model, were applied for the computations of beach evolution around a detached breakwater and two groins. It was confirmed that the presented model associated with the FAVOR method was useful to predict the nearshore current field in the vicinity of the complicated geometric shapes. Finally, the model was applied to a tombolo formation in a field site of Kunnui fishery port, which is located in Hokkaido, Japan.

  11. Bathymetry and acoustic backscatter: Elwha River Delta, Washington

    Science.gov (United States)

    Finlayson, David P.; Miller, Ian M.; Warrick, Jonathan A.

    2011-01-01

    Between February 22 and March 3, 2010, scientists from the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), acquired bathymetry and acoustic-backscatter data from the Elwha River Delta, Strait of Juan de Fuca, Washington, under PCMSC Field Activity ID S-6-10-PS. Three ancillary surveys were conducted when sea conditions were too rough for surveying outside the harbor breakwaters. The first ancillary survey was of the area surrounding the abandoned Rayonier Pier site in Port Angeles Harbor, a former log-storage facility on the southern side of Ediz Hook near the Port Angeles Coast Guard Station. Finally, several lines of bathymetry and backscatter data were collected on the outer face of Ediz Hook as the vessel transited to and from the Elwha River Delta. These data were collected to inspect failure features along the northern edge of Ediz Hook that were first observed in 2005 during USGS cruise K-1-05-PS.

  12. Beach nourishment alternative assessment to constrain cross-shore and longshore sediment transport

    Science.gov (United States)

    Karasu, Servet; Work, Paul; Uzlu, Ergun; Kankal, Murat; Yuksek, Omer

    2016-01-01

    A combined field and laboratory investigation was conducted to assess five options for creation of a recreational beach on a steep, armored shoreline on the eastern Black Sea coast. All designs incorporated a beach nourishment project placed between two existing, shore-normal, rubble-mound groins. Alternatives included the placement of a nearshore berm, longshore extensions added to the existing groins, and shore-parallel breakwaters. Several alternatives are reviewed for quantifying the performance of each design, including assessment of the change in shoreline position and project volume retained between the groins. Dimensionless benefits and benefit-cost ratios are quantified, and recommendations made on how to select the best outcome from a benefit-to-cost standpoint when options including hard structures are incorporated into a beach nourishment project design.

  13. The effectiveness of coral reefs for coastal hazard risk reduction and adaptation

    Science.gov (United States)

    Ferrario, Filippo; Beck, Michael W.; Storlazzi, Curt D.; Micheli, Fiorenza; Shepard, Christine C.; Airoldi, Laura

    2014-01-01

    The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97%. Reef crests alone dissipate most of this energy (86%). There are 100 million or more people who may receive risk reduction benefits from reefs or bear hazard mitigation and adaptation costs if reefs are degraded. We show that coral reefs can provide comparable wave attenuation benefits to artificial defences such as breakwaters, and reef defences can be enhanced cost effectively. Reefs face growing threats yet there is opportunity to guide adaptation and hazard mitigation investments towards reef restoration to strengthen this first line of coastal defence.

  14. Violent breaking wave impacts

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Peregrine, D.H.; Bullock, G.N.

    2009-01-01

    a better understanding of the processes involved. The wave's approach towards a structure is modelled with classical irrotational flow to obtain the different types of impact profiles that may or may not lead to air entrapment. The subsequent impact is modelled with a novel compressible-flow model...... local error. The high pressures measured during wave impacts on a breakwater are reproduced and it is shown that trapped air can be compressed to a pressure of several atmospheres. Pressure shock waves, reflected off nearby surfaces such as the seabed, can lead to pressures comparable with those...... for a homogeneous mixture of incompressible liquid and ideal gas. This enables a numerical description of both trapped air pockets and the propagation of pressure shock waves through the aerated water. An exact Riemann solver is developed to permit a finite-volume solution to the flow model with smallest possible...

  15. Subcellular evidences of redox imbalance in well-established populations of an endangered limpet. Reasons for alarm?

    Science.gov (United States)

    Espinosa, Free; Rivera-Ingraham, Georgina A

    2016-08-15

    Intertidal species are more vulnerable to anthropogenic disturbances than others inhabiting subtidal and offshore habitats. Coastal development frequently results in trace-metal pollution. For endangered species such as Patella ferruginea it can be a high risk that leads local populations to extinction. Three localities were surveyed, one within a natural and unpolluted area and the other two within the harbor of Ceuta (Strait of Gibraltar), on breakwaters outside and inside. The specimens collected inside the harbor reached 3-fold higher Hg content than for those incoming from the natural area. PERMANOVA test indicated that metal composition of the specimens from inside the harbor was different from the rest. In addition, evidence of cell damage was detected in the specimens from the harbor area. This highlights the urgency of undertaking a physiological evaluation of some of the most vulnerable populations, establishing eco-physiological protocols for monitoring and managing populations settled on artificial substrata. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Analysis of some solutions to protect the western tombolo of Giens

    CERN Document Server

    Van Than, Van; Liardet, Pierre; Leandri, Didier

    2014-01-01

    The tombolo of Giens is located in the town of Hyeeres (France). We recall the history of coastal erosion, and proeminent factors affecting the evolution of the western tombolo. We then discuss the possibility of stabilizing the western tombolo. Our argumentation relies on a coupled model integrating swells, currents, water levels and sediment transport. We present the conclusions of the simulations of various scenarios, including pre-existing propositions from coastal engineering offices. We conclude that beach replenishment seems to be necessary but not sufficient for the stabilization of the beach. Breakwaters reveal effective particularly in the most exposed northern area. Some solutions fulfill conditions so as to be elected as satisfactory. We give a comparative analysis of the efficiency of 14 alternatives for the protection of the tombolo.

  17. Long term morphological modelling

    DEFF Research Database (Denmark)

    Kristensen, Sten Esbjørn; Deigaard, Rolf; Taaning, Martin

    2010-01-01

    in the surf zone. Two parameterization schemes are tested for two different morphological phenomena: 1) Shoreline changes due to the presence of coastal structures and 2) alongshore migration of a nearshore nourishment and a bar by-passing a harbour. In the case of the shoreline evolution calculations......, a concept often used in one-line modelling of cross-shore shifting of an otherwise constant shape cross-shore profile is applied for the case of a groyne and a detached breakwater. In the case of alongshore bar/nourishment migration an alternative parameterization is adopted. All examples are presented......, analysed and discussed with respect to the question of realistic representation, time scale and general applicability of the model concept....

  18. Erosion Pressure on the Danish Coasts

    DEFF Research Database (Denmark)

    Sørensen, Carlo Sass; Sørensen, Per; Kroon, Aart

    Coastlines around the world are receding due to coastal erosion.With rising sea levels and a potential climatic deterioration due to climate change, erosion rates are likely to increase at many locations in the future.Together with the current preference of people to settle near or directly...... by the ocean, coastal erosion issues become increasingly more important to the human values at risk. Along many Danish coastlines, hard structures already act as coastal protection in the form of groins, breakwaters, revetments etc. These eroding coasts however still lack sand and where the public, in general......, neglects the need for sand replenishment i.e. in the form of repeated sand nourishments. Here we present a conceptual model and method for dividing coastal erosion into acute and chronic erosion pressure, respectively. We focus on the model use for management and climate change adaptation purposes...

  19. Mirmecofauna (Hymenoptera, Formicidae de Duas Marismas do Estuário da Lagoa dos Patos, RS: Diversidade, Flutuação de Abundância e Similaridade como Indicadores de Conservação

    Directory of Open Access Journals (Sweden)

    Cristiane Bolico

    2012-03-01

    Abstract. The aim of this investigation was to assess the myrmecofauna of two distinct salt marshes and to estimate the diversity, similarity, as well as to estimate the effects of temperature, relative humidity and rainfall on the fluctuation patterns of these insects. Additionally, the species that act as environmental indicators were recognized. The study was conducted in two salt marshes located in the Patos Lagoon Estuary: Torotama’s Island and West Breakwater. A total of 853 ants were sampled, distributed in 19 genera. Both marshes showed similar diversity and abundance, Ds = 0.958 and I = 0.042 in Torotama’s Island and Ds = 0.8889 and I = 0.111 in West Break Water. Trends in ant composition coincided in both areas, with a peak during the warmer months. Areas showed no similarity, due to anthropogenic factors and species’ biology. Groups considered as biomarkers were recorded in the samples, providing parameters for environmental conservation.

  20. COMPARISON OF NUMERICAL AND EXPERIMENTAL RESULTS FOR OVERTOPPING DISCHARGE OF THE OBREC WAVE ENERGY CONVERTER

    Directory of Open Access Journals (Sweden)

    A. YAZID MALIKI

    2017-05-01

    Full Text Available OBREC is the latest innovation of overtopping wave energy converter (WEC which is coalesced with the rubble mound breakwaters. The acquisition of wave overtopping in a front reservoir and consequently releasing process through turbine is the concept of energy production in OBREC. The physical scale model studies of overtopping discharge of the OBREC have recently been done by previous researcher in wave flume at Aalborg University. This paper demonstrates the overtopping behavior of OBREC device using a VOF method with capabilities to solve RANS equation in the numerical suite Flow3D. The purpose of this research is to validate the overtopping discharge performance of the numerical model against the experiments of the OBREC. Based on the observation, the results have shown a good agreement between the validation and physical experiment.

  1. Geoarchaeology and geomorphology of Phoenicus ancient harbor, NW coast of Egypt

    Science.gov (United States)

    Moustafa, Samah; Torab, Magdy

    2016-04-01

    Phoenicus Greek harbor located in SE coastline of Ras El Hekma area, west of Alexandria city for about 220 km. It is shaped as triangle with its headland extending into the Mediterranean Sea for about 15 km. It is occupied by sedimentary rocks belonging to the Tertiary and Quaternary Eras, the western coastline consists of Pleistocene, Separated polygons of limestone sheets and fossil lime stone, where there are coastal platforms, fluvial forms and solution holes. The location and description of Phoenicus ancient harbor were mentioned by some late writers (Fourtau,1893) & (Muller,1901), some geoarchaeological indicators were discovered by the authors such as fish tanks, well, remains of breakwater and wine press. The present work is mainly devoted to define the geomorphological and geoarchaelological indicators of Phoenicus Greek harbor site, based on detailed geomorphological and geoarchaelogical surveying, sampling, dating and mapping as well as satellite image interpretation and GIS techniques.

  2. Design and construction of an export harbour in Persian Gulf

    Energy Technology Data Exchange (ETDEWEB)

    Karimzadegan, K. [Horizon Engineering Inc., North Vancover, BC (Canada); Raissi, H. [Tehran Berkeley Engineers, Tehran (Iran, Islamic Republic of)

    2001-07-01

    Design and construction of the Pars Sulphur Export Harbour near the city of Beshar, in southern Iran on the Persian Gulf, to accommodate 15,000 DWT (deadweight) general cargo vessels is described. Although the steep drop of the ground near the shore was ideal for ship-berthing facilities, the construction of the associated breakwater in very deep waters required a significant amount of land reclamation (102,000 sq m, with a depth of backfilling up to eight metres and volume of about 550,000 cu m). The paper provides design details for filling the reclamation area in an economical way. It also describes the construction management and control issues that had to be dealt with to allow for the successful completion of the project within the approved budget. 5 tabs., 5 figs.

  3. Mathematical and Numerical Modeling in Maritime Geomechanics

    Directory of Open Access Journals (Sweden)

    Miguel Martín Stickle

    2012-04-01

    Full Text Available A theoretical and numerical framework to model the foundation of marine offshore structures is presented. The theoretical model is composed by a system of partial differential equations describing coupling between seabed solid skeleton and pore fluids (water, air, oil,... combined with a system of ordinary differential equations describing the specific constitutive relation of the seabed soil skeleton. Once the theoretical model is described, the finite element numerical procedure to achieve an approximate solution of the overning equations is outlined. In order to validate the proposed theoretical and numerical framework the seaward tilt mechanism induced by the action of breaking waves over a vertical breakwater is numerically reproduced. The results numerically attained are in agreement with the main conclusions drawn from the literature associated with this failure mechanism.

  4. Lactuca tatarica (Asteraceae in embryonic dunes on Wolin Island (NW Poland

    Directory of Open Access Journals (Sweden)

    W. A. Wojciech Kowalski

    2015-09-01

    Full Text Available By the end of the 19th century, Lactuca tatarica was reported for the first time from an adventive occurrence on the North Sea and Baltic Sea coasts. In Wolin Island, the species has become established in the natural habitat and is clearly spreading in recent years. The community with L. tatarica was studied currently on the western point of Wolin Island along the stretch between the mouth of the Świna (Swine River and a newly constructed breakwater of the external harbour. The taxon occupies relatively low parts of the sandy elevations of dune ridges, in patches of the Honckenyo-Agropyretum juncei association (habitat 2110. Furthermore, L. tatarica has been reported in recent years from some locations in Świnoujście (Usedom (Uznam Island, Międzyzdroje, Wisełka and Międzywodzie.

  5. Impulse waves due to avalanche impact into Kuehtai reservoir; Impulswellen infolge Lawineneinstoss in den Speicher Kuehtai

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Helge; Pfister, Michael; Boes, Robert [ETH Zuerich (CH). Versuchsanstalt fuer Wasserbau, Hydrologie und Glaziologie (VAW); Perzlmaier, Sebastian; Reindl, Robert [Tiroler Wasserkraft AG (TIWAG), Innsbruck (Austria). Bereich Engineering Services

    2011-07-01

    The Tyrolean Hydropower Company TIWAG-Tiroler Wasserkraft AG plans the Kuehtai reservoir as an addition to the existing pump-storage scheme Sellrain-Silz. Two relevant natural hazards potentially affecting the dam were identified: an avalanche near the dam axis and a rockslide further upstream, both possibly impinging the reservoir at full supply level and thereby generating impulse waves. A preliminary analysis based on literature led to the conclusion that dam overtopping cannot be excluded. The Laboratory of Hydraulics, Hydrology and Glaciology (VAW) of ETH Zurich was therefore assigned to perform related hydraulic model tests. However, no overtopping occurred in these model tests, such that no measures as breakwater or increase of the freeboard were required. The article discusses the effect of avalanche generated impulse waves and compares an analytical estimation with results derived from the model tests. (orig.)

  6. The numerical model of the sediment distribution pattern at Lampulo National fisheries port

    Science.gov (United States)

    Irham, M.; Setiawan, I.

    2018-01-01

    The spatial distribution of sediment pattern was studied at Lampulo Fisheries Port, Krueng Aceh estuarial area, Banda Aceh. The research was conducted using the numerical model of wave-induced currents at shallow water area. The study aims to understand how waves and currents react to the pattern of sediment distribution around the beach structure in that region. The study demonstrated that the port pool area had no sedimentation and erosion occurred because the port was protected by the jetty as the breakwater to defend the incoming waves toward the pool. The protected pool created a weak current circulation to distribute the sediments. On the other hand, the sediments were heavily distributed along the beach due to the existence of longshore currents near the shoreline (outside the port pool area). Meanwhile, at the estuarial area, the incoming fresh water flow responded to the coastal shallow water currents, generating Eddy-like flow at the mouth of the river.

  7. Gas transfer under breaking waves: experiments and an improved vorticity-based model

    Directory of Open Access Journals (Sweden)

    V. K. Tsoukala

    2008-07-01

    Full Text Available In the present paper a modified vorticity-based model for gas transfer under breaking waves in the absence of significant wind forcing is presented. A theoretically valid and practically applicable mathematical expression is suggested for the assessment of the oxygen transfer coefficient in the area of wave-breaking. The proposed model is based on the theory of surface renewal that expresses the oxygen transfer coefficient as a function of both the wave vorticity and the Reynolds wave number for breaking waves. Experimental data were collected in wave flumes of various scales: a small-scale experiments were carried out using both a sloping beach and a rubble-mound breakwater in the wave flume of the Laboratory of Harbor Works, NTUA, Greece; b large-scale experiments were carried out with a sloping beach in the wind-wave flume of Delft Hydraulics, the Netherlands, and with a three-layer rubble mound breakwater in the Schneideberg Wave Flume of the Franzius Institute, University of Hannover, Germany. The experimental data acquired from both the small- and large-scale experiments were in good agreement with the proposed model. Although the apparent transfer coefficients from the large-scale experiments were lower than those determined from the small-scale experiments, the actual oxygen transfer coefficients, as calculated using a discretized form of the transport equation, are in the same order of magnitude for both the small- and large-scale experiments. The validity of the proposed model is compared to experimental results from other researchers. Although the results are encouraging, additional research is needed, to incorporate the influence of bubble mediated gas exchange, before these results are used for an environmental friendly design of harbor works, or for projects involving waste disposal at sea.

  8. Experimental study on the method of estimating the vertical design wave force acting on a submerged dual horizontal plate

    Directory of Open Access Journals (Sweden)

    Hyuck-Min Kweon

    2013-12-01

    Full Text Available A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005, and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011 proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011, and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011 was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974 that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011. The method of Kweon (2011 was already verified in the real sea test of Kweon et al. (2012, where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011 can be satisfactorily used for estimating the uplift force of a pile.

  9. The Geomorphic System and the Effects of Human Interference at Gold Coast Beach in Tainan, Taiwan

    Science.gov (United States)

    Lin, Tsung-Yi

    2017-04-01

    The Gold Coast beach in Tainan, Taiwan, located between Anping harbor and Ur-Jen river mouth, is the subject of this study, which characterizes the beach's geomorphic system through the analysis of information such as sediment grain size, mineral composition, and periodic measurements of morphological changes of the beach. Based upon such characterizations, further analysis is conducted on the effects that human activities of the last 15 years have upon the geomorphic changes within the Gold Coast beach. The study shows that the median grain size of the Gold Coast beach's sediment is medium sand. The mineral composition includes mainly slate fragments and quartz grains, with small amounts of feldspar, sandstone and shell fragments. Based on a comprehensive study of the longshore distribution of beach sediment size and mineral composition of southwestern coast of Taiwan, as well as, the long-term, monitored data of waves, tides, and currents in this region, we conclude that the main process responsible for the sand accumulation at Gold Coast beach is the prevailing longshore sand transport from south to north. The southern breakwater of Anping harbor plays a role in intercepting the longshore transport sand and helps form the beach. Since the Ur-Jen river flows through a mudstone region, the suspended sediment plume during the flood season does not provide much sediment source to the sandy beach. A monthly beach profile survey project conducted between the years 1999 to 2000 revealed that the beach elevation and width had experienced an obvious seasonal change. The beach widened during the winter, but narrowed in the summer due to typhoon wave erosion. When the subaerial beach was eroded, a submerged longshore bar that was oriented almost parallel to the shoreline had formed at a distance about 400-600 meter away. With this observation, we can conclude that beach morphology is also influenced by various seasonal wave actions that affect onshore and offshore sand

  10. Morphodynamic changes as an impact of human intervention at the Ras El-Bar-Damietta Harbor coast, NW Damietta Promontory, Nile Delta, Egypt

    Science.gov (United States)

    El-Asmar, Hesham M.; Taha, Maysa M. N.; El-Sorogy, Abdelbaset S.

    2016-12-01

    Due to the absence of a national strategic plan for coastal management, the Nile Delta coast is no longer described as a fully dissipative, divergent, low-gradient beach face composed of fine to very fine sand. Instead, new patterns have emerged depending on rock type, geomorphology of the coast, direction of the shoreline in relation to waves and current, and the implemented defense measures. This study attempts to record the morphodynamic changes which occurred due to human intervention. Landsat satellite images acquired for the periods of time of 1973, 1984, 1989, 2003, and 2015 are used together with geomorphologic observations in order to monitor the changes along the coastal strip between Ras El-Bar and Damietta Harbor. This study reveals two beach segments; one of which lies to the east, it is protected with detached breakwater system, and shows average shoreline accretions of +4.73 myr-1, +5.0 myr-1, and +0.89myr-1 during the periods of 1984-1998, 1998-2003, and 2003-2015 respectively. This segment still has the geomorphologic imprints of the dissipative beach, wave divergence, low-gradient beach face, fine grained sand and spilling breakers. The second is to the west, between the detached breakwaters and the eastern jetty of the Damietta Harbor. It is an erosional segment with shoreline retreat of -7.43 myr-1, -10.90 myr-1, and -3.11myr-1 for the same periods. This segment shows intermediate "d" beach or intermediate-reflective, wave convergence, rip currents, with the characteristic steep sloped and cuspate beach face, cliffy, reworked sediments of coarse grained sands, mud clasts, discoidal gravels, shelly beach, and plunging breakings. The presence of convergent waves along this segment confirms the concept of an emergence of a new wave pattern of reversed eddy which enhances the steepness of the beach face, accelerates erosion, and increases the possibility of drowning of swimmers at Ras El-Bar resort. Under such circumstances the plunge step

  11. Environmental policy in the north-eastern sector of the Black sea coast

    Science.gov (United States)

    Kosyan, Ruben; Godin, Evgenii; Kosyan, Alisa

    2015-04-01

    becomes crucial. For a long period of time the coast protective activity was concentrated on elimination of localized zones of washout, without consideration of lithodynamic system in which the protected area is located, that led to disturbance of sediments flows, and, consequently, to acceleration of abrasion on the related parts of the shore. Main technical solutions regarding coast protection constructions for creation of artificial beaches, are borrowed from the experience of coast protection (construction of bunas, breakwaters and wave walls) at Caucasus and Crimean shores of the Black Sea. Application of bunas and breakwaters is formally divided by the steepness of the underwater slope equal to 0.03. However, this division did not and does not have any physical grounds and is not confirmed by materials of study of surf zone's hydro- and lithodynamics. Types of constructions and their composition in the coastal protective complexes were assigned subjectively. Because of general deficit of the sediments, the free beaches with big length were difficult to create. It was neces- sary to build the sediment retaining constructions like bunas, on the landslide sections - underwater breakwaters. Thus, the beaches in the coast protective complexes were having a primary role, and the constructions - secondary.

  12. An innovative early warning system for floods and operational risks in harbours

    Science.gov (United States)

    Smets, Steven; Bolle, Annelies; Mollaert, Justine; Buitrago, Saul; Gruwez, Vincent

    2016-04-01

    Early Warning Systems (EWS) are nowadays becoming fairly standard in river flood forecasting or in large scale hydrometeorological predictions. For complex coastal morphodynamic problems or in the vicinity of complex coastal structures, such as harbours, EWS are much less used because they are both technically and computationally still very challenging. To advance beyond the state-of-the-art, the EU FP7 project Risc-KIT (www.risc-kit.eu) is developing prototype EWS which address specifically these topics. This paper describes the prototype EWS which IMDC has developed for the case study site of the harbour of Zeebrugge. The harbour of Zeebrugge is the largest industrial seaport on the coast of Belgium, extending more than 3 km into the sea. Two long breakwaters provide shelter for the inner quays and docks for regular conditions and frequent storms. Extreme storms surges and waves can however still enter the harbour and create risks for the harbour operations and infrastructure. The prediction of the effects of storm surges and waves inside harbours are typically very complex and challenging, due to the need of different types of numerical models for representing all different physical processes. In general, waves inside harbours are a combination of locally wind generated waves and offshore wave penetration at the port entrance. During extreme conditions, the waves could overtop the quays and breakwaters and flood the port facilities. Outside a prediction environment, the conditions inside the harbour could be assessed by superimposing processes. The assessment can be carried out by using a combination of a spectral wave model (i.e. SWAN) for the wind generated waves and a Boussinesq type wave model (i.e. Mike 21 BW) for the wave penetration from offshore. Finally, a 2D hydrodynamic model (i.e. TELEMAC) can be used to simulate the overland flooding inside the port facilities. To reproduce these processes in an EWS environment, an additional challenge is to cope

  13. Archaeogeophysical Studies in Ancient Tios, Zonguldak-Caycuma-Filyos, Turkey

    Science.gov (United States)

    Ahmet Yuksel, Fethi; Hoskan, Nihan; Sumer Atasoy, Yusuf

    2010-05-01

    Ancient Tios is located in the Filyos township of the Caycuma District of Zonguldak on the western Black Sea region, Turkey. The ancient city was probably founded by Milesians in the 7th cent. B.C. The region was inhabited through the centuries by Persians, Romans, Genoese and all the way to the Ottoman times. About the archaeological history of the city , we have relatively limited knowledge both in ancient records and in contemporary archaeological research. In the Roman period coastal defensive walls, acquaduct, theatre, defensive tower and the port with its breakwater are the only visible remains of the city. The acropolis of the ancient city is located immediately to the east of the present Filyos township on a hill. The original architectural form of the defensive wall located in the acropolis will be revealed after research to its foundation completed. A partially destroyed stone building is another remaining ruin in the acropolis .The Roman period theatre of Tios is located in the north of the road leading into Filyos. Built on a sloping land, local stones were used in its construction. Mostly ruined its original stones have been used later in other buildings. Only a few of the arches of the aquaduct, located to the north of the theatre, are still standing. There are the remains of another structure which could have been a defensive tower located in 200 meters to the west of the theatre. GPR measurements display the exact location of any sub-surface structures. To the west of the acropolis and within the ancient port, there are the under water remains of a breakwater. The local sandstones, quarries were studied archaeogeologically as they provided the main building materials. Since there has been no archaeological research done on the site until the 2006 season, archaeogeopysical data are reveal additional information about ancient Tios. Surface survey and georadar, magnetic and geoelectric studies have been done and after that, excavations were started

  14. High Resolution Tsunami Modeling and Assessment of Harbor Resilience; Case Study in Istanbul

    Science.gov (United States)

    Cevdet Yalciner, Ahmet; Aytore, Betul; Gokhan Guler, Hasan; Kanoglu, Utku; Duzgun, Sebnem; Zaytsev, Andrey; Arikawa, Taro; Tomita, Takashi; Ozer Sozdinler, Ceren; Necmioglu, Ocal; Meral Ozel, Nurcan

    2014-05-01

    Ports and harbors are the major vulnerable coastal structures under tsunami attack. Resilient harbors against tsunami impacts are essential for proper, efficient and successful rescue operations and reduction of the loss of life and property by tsunami disasters. There are several critical coastal structures as such in the Marmara Sea. Haydarpasa and Yenikapi ports are located in the Marmara Sea coast of Istanbul. These two ports are selected as the sites of numerical experiments to test their resilience under tsunami impact. Cargo, container and ro-ro handlings, and short/long distance passenger transfers are the common services in both ports. Haydarpasa port has two breakwaters with the length of three kilometers in total. Yenikapi port has one kilometer long breakwater. The accurate resilience analysis needs high resolution tsunami modeling and careful assessment of the site. Therefore, building data with accurate coordinates of their foot prints and elevations are obtained. The high resolution bathymetry and topography database with less than 5m grid size is developed for modeling. The metadata of the several types of structures and infrastructure of the ports and environs are processed. Different resistances for the structures/buildings/infrastructures are controlled by assigning different friction coefficients in a friction matrix. Two different tsunami conditions - high expected and moderate expected - are selected for numerical modeling. The hybrid tsunami simulation and visualization codes NAMI DANCE, STOC-CADMAS System are utilized to solve all necessary tsunami parameters and obtain the spatial and temporal distributions of flow depth, current velocity, inundation distance and maximum water level in the study domain. Finally, the computed critical values of tsunami parameters are evaluated and structural performance of the port components are discussed in regard to a better resilience. ACKNOWLEDGEMENTS: Support by EU 603839 ASTARTE Project, UDAP-Ç-12

  15. HySEA model verification for Tohoku 2011 Tsunami. Application for mitigation tsunami assessment

    Science.gov (United States)

    Macias, Jorge; González-Vida, José Manuel; García, Javier; Castro, Manuel; Ortega, Sergio; de la Asunción, Marc

    2015-04-01

    In many aspects Tohoku-Oki 2011 mega tsunami has changed our perception of tsunami risk. The tsunami-HySEA model is used to numerically simulate this event and observed data will we used to verify the model results. Three nested meshes of enhanced resolution (4 arc-min, 32 arc-sec and 2 arc-sec) will be used by the numerical model. The propagation mesh covers all Pacific Ocean with more of 7 million cells. An intermediate mesh with 5 millions cells contains the Japanese archipelago and, finally, two finer meshes, with nearly 8 and 6 millions cells, cover Iwate and Miyagi Prefectures at Tohoku region, the most devastated areas hit by the tsunami. The presentation will focus on the impact of the tsunami wave in these two areas and comparisons with observed data will be performed. DART buoys time series, inundation area and observed runup is used to assess model performance. The arrival time of the leading flooding wave at the vicinity of the Senday airport, as recorded by video cameras, is also used as verification data for the model. After this tsunami, control forests as well as breakwaters has been discussed as suitable mitigation infrastructures. As particular case, we will analyse the evolution of the tsunami in the area around the Sendai airport (Miyagi Prefecture) and its impact on the airport. A second simulation has been performed, assuming the existence of a coastal barrier protecting the area. The role of this barrier in modifying tsunami wave evolution and mitigating flooding effects on the airport area are discussed. The protection effect of the breakwaters near Kamaishi (Iwate Prefecture) is also assessed. The numerical model shows how these structures, although did not provide a full protection to tsunami waves, they helped to largely mitigate its effects in the area. Acknowledgements. This research has been partially supported by the Junta de Andalucía research project TESELA (P11-RNM7069), the Spanish Government Research project DAIFLUID (MTM2012

  16. Insights from interviews regarding high fatality rate caused by the 2011 Tohoku-Oki earthquake

    Science.gov (United States)

    Ando, M.; Ishida, M.

    2012-12-01

    The 11 March 2011 Tohoku-Oki earthquake (Mw9.0) caused approximately 19,000 casualties including missing persons along the entire coast of the Tohoku region. Three historical tsunamis occurred in the past 115 years preceding this tsunami. Since these tsunamis, numerous countermeasures against future tsunamis such as breakwaters, early tsunami warning systems and tsunami evacuation drills were implemented. Despite the preparedness, a number of deaths and missing persons occurred. Although this death rate is approximately 4 % of the population in severely inundated areas; 96 % safely evacuated or managed to survive the tsunami. To understand why some people evacuated immediately while others delayed; survivors were interviewed in the northern part of the Tohoku region. Our interviews revealed that many residents obtained no appropriate warnings and many chose to remain in dangerous locations partly because they obtained the wrong idea of the risks. In addition, our interviews also indicated that the resultant high casualties were due to current technology malfunction, underestimated earthquake size and tsunami heights, and failure of warning systems. Furthermore, the existing breakwaters provided the local community a false sense of security. The advanced technology did not work properly, especially at the time of the severe disaster. If residents had taken an immediate action after the major shaking stopped, most local residents might have survived considering that safer highlands are within 5 to 20 minute walking distance from the interviewed areas. However, the elderly and physically disabled people would still be in a much more difficult situation to walk such distance into safety. Nevertheless, even if these problems occur in future earthquakes, better knowledge regarding earthquakes and tsunami hazards could save more lives. People must take immediate action without waiting for official warning or help. To avoid similar high tsunami death ratios in the future

  17. Vulnerability of the Nigerian coast: An insight into sea level rise owing to climate change and anthropogenic activities

    Science.gov (United States)

    Danladi, Iliya Bauchi; Kore, Basiru Mohammed; Gül, Murat

    2017-10-01

    Coastal areas are important regions in the world as they host huge population, diverse ecosystems and natural resources. However, owing to their settings, elevations and proximities to the sea, climate change (global warming) and human activities are threatening issues. Herein, we report the coastline changes and possible future threats related to sea level rise owing to global warming and human activities in the coastal region of Nigeria. Google earth images, Digital Elevation Model (DEM) and geological maps were used. Using google earth images, coastal changes for the past 43 years, 3 years prior to and after the construction of breakwaters along Goshen Beach Estate (Lekki) were examined. Additionally, coastline changes along Lekki Phase I from 2013 to 2016 were evaluated. The DEM map was used to delineate 0-2 m, 2-5 m and 5-10 m asl which correspond to undifferentiated sands and gravels to clays on the geological map. The results of the google earth images revealed remarkable erosion along both Lekki and Lekki Phase I, with the destruction of a lagoon in Lekki Phase I. Based on the result of the DEM map and geology, elevations of 0-2 m, 2-5 m and 5-10 m asl were interpreted as highly risky, moderately risky and risky respectively. Considering factors threatening coastal regions, the erosion and destruction of the lagoon along the Nigerian coast may be ascribed to sea level rise as a result of global warming and intense human activities respectively.

  18. Effects of reverse waves on the hydrodynamic pressure acting on a dual porous horizontal plate

    Directory of Open Access Journals (Sweden)

    Kweon Hyuck-Min

    2014-03-01

    Full Text Available The seaward reverse wave, occurring on the submerged dual porous horizontal plate, can contribute to the reduction of the transmitted wave as it reflects the propagating wave. However, the collision between the propa¬gating and seaward reverse waves increases the water level and acts as a weight on the horizontal plate. This study investigated the characteristics of the wave pressure created by the seaward reverse wave through the analysis of expe¬rimental data. The analysis confirmed the following results: 1 the time series of the wave pressure showed reverse phase phenomena due to the collision, and the wave pressures acted simultaneously on both upper and lower surfaces of the horizontal plate; 2 the horizontal plate became repeatedly compressed and tensile before and after the occur¬rence of the seaward reverse wave; and 3 the seaward reverse wave created the total wave pressure to the maximum towards the direction of gravity, primarily on the upper plate. It was also confirmed that the wave distributions showed a similar trend to the wave steepness. Such outcome of the analysis will provide basic information to the structural analysis of the horizontal plate as a wave dissipater of the steel-type breakwater (STB.

  19. Effects of reverse waves on the hydrodynamic pressure acting on a dual porous horizontal plate

    Directory of Open Access Journals (Sweden)

    Hyuck-Min Kweon

    2014-03-01

    Full Text Available The seaward reverse wave, occurring on the submerged dual porous horizontal plate, can contribute to the reduction of the transmitted wave as it reflects the propagating wave. However, the collision between the propagating and seaward reverse waves increases the water level and acts as a weight on the horizontal plate. This study investigated the characteristics of the wave pressure created by the seaward reverse wave through the analysis of experimental data. The analysis confirmed the following results: 1 the time series of the wave pressure showed reverse phase phenomena due to the collision, and the wave pressures acted simultaneously on both upper and lower surfaces of the horizontal plate; 2 the horizontal plate became repeatedly compressed and tensile before and after the occurrence of the seaward reverse wave; and 3 the seaward reverse wave created the total wave pressure to the maximum towards the direction of gravity, primarily on the upper plate. It was also confirmed that the wave distributions showed a similar trend to the wave steepness. Such outcome of the analysis will provide basic information to the structural analysis of the horizontal plate as a wave dissipater of the steel-type breakwater (STB.

  20. Depth-Averaged Non-Hydrostatic Hydrodynamic Model Using a New Multithreading Parallel Computing Method

    Directory of Open Access Journals (Sweden)

    Ling Kang

    2017-03-01

    Full Text Available Compared to the hydrostatic hydrodynamic model, the non-hydrostatic hydrodynamic model can accurately simulate flows that feature vertical accelerations. The model’s low computational efficiency severely restricts its wider application. This paper proposes a non-hydrostatic hydrodynamic model based on a multithreading parallel computing method. The horizontal momentum equation is obtained by integrating the Navier–Stokes equations from the bottom to the free surface. The vertical momentum equation is approximated by the Keller-box scheme. A two-step method is used to solve the model equations. A parallel strategy based on block decomposition computation is utilized. The original computational domain is subdivided into two subdomains that are physically connected via a virtual boundary technique. Two sub-threads are created and tasked with the computation of the two subdomains. The producer–consumer model and the thread lock technique are used to achieve synchronous communication between sub-threads. The validity of the model was verified by solitary wave propagation experiments over a flat bottom and slope, followed by two sinusoidal wave propagation experiments over submerged breakwater. The parallel computing method proposed here was found to effectively enhance computational efficiency and save 20%–40% computation time compared to serial computing. The parallel acceleration rate and acceleration efficiency are approximately 1.45% and 72%, respectively. The parallel computing method makes a contribution to the popularization of non-hydrostatic models.

  1. Bleaching drives collapse in reef carbonate budgets and reef growth potential on southern Maldives reefs

    Science.gov (United States)

    Perry, C. T.; Morgan, K. M.

    2017-01-01

    Sea-surface temperature (SST) warming events, which are projected to increase in frequency and intensity with climate change, represent major threats to coral reefs. How these events impact reef carbonate budgets, and thus the capacity of reefs to sustain vertical growth under rising sea levels, remains poorly quantified. Here we quantify the magnitude of changes that followed the ENSO-induced SST warming that affected the Indian Ocean region in mid-2016. Resultant coral bleaching caused an average 75% reduction in coral cover (present mean 6.2%). Most critically we report major declines in shallow fore-reef carbonate budgets, these shifting from strongly net positive (mean 5.92 G, where G = kg CaCO3 m-2 yr-1) to strongly net negative (mean -2.96 G). These changes have driven major reductions in reef growth potential, which have declined from an average 4.2 to -0.4 mm yr-1. Thus these shallow fore-reef habitats are now in a phase of net erosion. Based on past bleaching recovery trajectories, and predicted increases in bleaching frequency, we predict a prolonged period of suppressed budget and reef growth states. This will limit reef capacity to track IPCC projections of sea-level rise, thus limiting the natural breakwater capacity of these reefs and threatening reef island stability.

  2. Biofouling protection for marine environmental sensors

    Directory of Open Access Journals (Sweden)

    L. Delauney

    2010-05-01

    Full Text Available These days, many marine autonomous environment monitoring networks are set up in the world. These systems take advantage of existing superstructures such as offshore platforms, lightships, piers, breakwaters or are placed on specially designed buoys or underwater oceanographic structures. These systems commonly use various sensors to measure parameters such as dissolved oxygen, turbidity, conductivity, pH or fluorescence. Emphasis has to be put on the long term quality of measurements, yet sensors may face very short-term biofouling effects. Biofouling can disrupt the quality of the measurements, sometimes in less than a week.

    Many techniques to prevent biofouling on instrumentation are listed and studied by researchers and manufacturers. Very few of them are implemented on instruments and of those very few have been tested in situ on oceanographic sensors for deployment of at least one or two months.

    This paper presents a review of techniques used to protect against biofouling of in situ sensors and gives a short list and description of promising techniques.

  3. An alternative approach for addressing the failure probability-safety factor method with sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Enrique; Conejo, Antonio J.; Minguez, Roberto; Castillo, Carmen

    2003-11-01

    The paper introduces a method for solving the failure probability-safety factor problem for designing engineering works proposed by Castillo et al. that optimizes an objective function subject to the standard geometric and code constraints, and two more sets of constraints that simultaneously guarantee given safety factors and failure probability bounds associated with a given set of failure modes. The method uses the dual variables and is especially convenient to perform a sensitivity analysis, because sensitivities of the objective function and the reliability indices can be obtained with respect to all data values. To this end, the optimization problems are transformed into other equivalent ones, in which the data parameters are converted into artificial variables, and locked to their actual values. In this way, some variables of the associated dual problems become the desired sensitivities. In addition, using the proposed methodology, calibration of codes based on partial safety factors can be done. The method is illustrated by its application to the design of a simple rubble mound breakwater and a bridge crane.

  4. Conservation status and updated census of Patella ferruginea (Gastropoda, Patellidae in Ceuta: distribution patterns and new evidence of the effects of environmental parameters on population structure

    Directory of Open Access Journals (Sweden)

    Rivera–Ingraham, G. A.

    2011-06-01

    Full Text Available The Strait of Gibraltar has important populations of the highly endangered patellid limpet Patella ferruginea. Between 2006 and 2010, an exhaustive census was carried out in Ceuta. The total coastline was divided into 17 sectors. The coast of each sector was examined by using 10 m transects. For the case of those sectors composed of breakwaters, jetties or islets, no transects were used, and instead, the total number of individuals was recorded. Each individual was measured to the nearest millimetre using a calliper. Moreover, the complete rocky shore length where the species could potentially be present was calculated, and an estimation of the total number of individuals that each sector could host was made. Results indicate that Ceuta could be home to around 44,000 individuals. The species found in Point Benzú, its westernmost limit of distribution on the North African coasts. The largest populations were recorded on the South Bay, with higher Mediterranean influence. Our results indicate that substrate roughness (topographic heterogeneity and the area’s accessibility highly influence the abundance and population structure. Those populations located on high topographic heterogeneity substrates show higher recruitment rates and lower percentages of larger individuals, while medium to low rugosity surfaces presented the opposite pattern. Additionally, easily accessible areas (and frequented by humans presented smaller average shell sizes. Implications of the results for conservation purposes are discussed.

  5. A hydrodynamic model of nearshore waves and wave-induced currents

    Directory of Open Access Journals (Sweden)

    Ahmed Khaled Seif

    2011-09-01

    Full Text Available In This study develops a quasi-three dimensional numerical model of wave driven coastal currents with accounting the effects of the wave-current interaction and the surface rollers. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. The surface roller associated with wave breaking was modeled based on a modification of the equations by Dally and Brown (1995 and Larson and Kraus (2002. Furthermore, the quasi-three dimensional model, which based on Navier-Stokes equations, was modified in association with the surface roller effect, and solved using frictional step method. The model was validated by data sets obtained during experiments on the Large Scale Sediment Transport Facility (LSTF basin and the Hazaki Oceanographical Research Station (HORS. Then, a model test against detached breakwater was carried out to investigate the performance of the model around coastal structures. Finally, the model was applied to Akasaki port to verify the hydrodynamics around coastal structures. Good agreements between computations and measurements were obtained with regard to the cross-shore variation in waves and currents in nearshore and surf zone.

  6. Hydrodynamic conditions in front of a vertical wall with an overhanging horizontal cantilever slab

    Science.gov (United States)

    Kisacik, Dogan; Ozyurt, Gulizar; Troch, Peter

    2017-12-01

    Transforming wave heights from offshore to the shoreline is the first step of any coastal engineering work. Wave breaking is analyzed to understand hydrodynamic conditions. For vertical breakwaters and sea walls, wave reflection is an important process that affects the determination of the wave height. Many of the design formulas presented in the literature depend on empirical studies based on the structures tested. In this study, the hydrodynamic conditions in front of a vertical wall with an overhanging horizontal cantilever slab with a foreshore slope of 1/20 are determined experimentally under regular wave conditions to assess the applicability of the formulas of Goda (2000) for predicting the nearshore wave height and breaker index equation (Goda, 2010). The selection of wave measurements used to determine the design wave height, the reflection coefficients, and wave breaking is also analyzed, and the reflection equations are derived from the dataset covering different breaker types. Small-scale tests show that the incident wave height is a good representative of the design wave height and that the values predicted by Goda are in good agreement with actual measurements. However, the predicted H max values are overestimated. In addition, the inception of the wave breaking point is postponed because of the reflection and/or turbulence left over from preceding waves, which is an effect of the vertical wall. At higher water levels, the effect of the vertical wall on the inception point becomes more significant.

  7. Liquid spray experiments

    Science.gov (United States)

    Lapham, Gary; McHugh, John

    When waves on the ocean surface interact with a solid object, the result is often a complex pattern of spray. The solid object may be a coastal barrier such as a breakwater, or a ship or drilling rig. Another spray-related case is the presence of large industrial tanks of liquid, and often dangerous liquids, that exist around the world. Tens of thousands of such tanks are rapidly becoming obsolete. Recent experience has shown that when such tanks burst, the resulting spray may shoot several hundreds of meters from the tank. These tanks often have a wall or dam (barrier) surrounding them in an attempt to contain any leakage, catastrophic or otherwise. When the tank bursts it is akin to the dam-break problem. A wall of water rushes forth and impinges on the barrier creating spray. Previous experiments (McHugh and Watt, 1998) considered the related configuration of a solitary wave impinging on a vertical wall. The present experiments more closely model the bursting tank case, and treat the effect of the distance between the tank and barrier. Results show that there is a sweet spot where height and horizontal distance of spray droplets are maximized. This ideal distance between tank and barrier is constant when scaled by the initial tank depth.

  8. On the role of impermeable groins on barred beach morphodynamics: Example of Matalascañas beach, Spain

    Science.gov (United States)

    Sedrati, Mouncef; Morales González, Juan Antonio

    2017-04-01

    Several studies on barred beaches in settings with mesotidal to macrotidal regimes have focused on cross-shore and alongshore bar mobility. Whereas the general link between hydrodynamics, sediment transport and the response of the intertidal bars and shoreline evolution has been recognized in the literature, the role of coastal defense structures (Breakwaters, groins, seawalls) on bar-trough systems morphodynamics have received more much less attention and the field-based experimental studies of these environments are rare. The main aim of this paper is to highlight the contrasting behavior of a natural and protected barred beach under several hydrodynamics conditions. This paper presents detailed hydrodynamic and morphological data from a field experiment spanning 10 days undertaken in Matalascañas beach, a mesotidal protected vs natural barred beach in the Southern Spanish coast. This mesotidal beach experienced intense erosion in the recent past and therefore it has been partially protected by groins (protection of sea-front touristic residences). During the fieldwork, an intertidal bars in the protected and non-protected areas highlighted contrasting morphological behaviour. The non-protected barred beach shows a less pronounced bar-trough system than the protected zone. Under low energy conditions (significant wave height 1m), the protected and non-protected zones show a flattening bars processes. The findings of the present study suggest that cross-shore vs longshore bar mobility may even be mitigated by the presence of the groins, which favour onshore than longshore bar migration.

  9. Modeling of coastal water contamination in Fortaleza (Northeastern Brazil).

    Science.gov (United States)

    Pereira, S P; Rosman, P C C; Alvarez, C; Schetini, C A F; Souza, R O; Vieira, R H S F

    2015-01-01

    An important tool in environmental management projects and studies due to the complexity of environmental systems, environmental modeling makes it possible to integrate many variables and processes, thereby providing a dynamic view of systems. In this study the bacteriological quality of the coastal waters of Fortaleza (a state capital in Northeastern Brazil) was modeled considering multiple contamination sources. Using the software SisBaHiA, the dispersion of thermotolerant coliforms and Escherichia coli from three sources of contamination (local rivers, storm drains and submarine outfall) was analyzed. The models took into account variations in bacterial decay due to solar radiation and other environmental factors. Fecal pollution discharged from rivers and storm drains is transported westward by coastal currents, contaminating strips of beach water to the left of each storm drain or river. Exception to this condition only occurs on beaches protected by the breakwater of the harbor, where counterclockwise vortexes reverse this behavior. The results of the models were consistent with field measurements taken during the dry and the rainy season. Our results show that the submarine outfall plume was over 2 km from the nearest beach. The storm drains and the Maceió stream are the main factors responsible for the poor water quality on the waterfront of Fortaleza. The depollution of these sources would generate considerable social, health and economic gains for the region.

  10. Long-Term Assessment of an Innovative Mangrove Rehabilitation Project: Case Study on Carey Island, Malaysia

    Directory of Open Access Journals (Sweden)

    Shervin Motamedi

    2014-01-01

    Full Text Available Wave energy and storm surges threaten coastal ecology and nearshore infrastructures. Although coastal structures are conventionally constructed to dampen the wave energy, they introduce tremendous damage to the ecology of the coast. To minimize environmental impact, ecofriendly coastal protection schemes should be introduced. In this paper, we discuss an example of an innovative mangrove rehabilitation attempt to restore the endangered mangroves on Carey Island, Malaysia. A submerged detached breakwater system was constructed to dampen the energy of wave and trap the sediments behind the structure. Further, a large number of mangrove seedlings were planted using different techniques. Further, we assess the possibility of success for a future mangrove rehabilitation project at the site in the context of sedimentology, bathymetry, and hydrogeochemistry. The assessment showed an increase in the amount of silt and clay, and the seabed was noticeably elevated. The nutrient concentration, the pH value, and the salinity index demonstrate that the site is conducive in establishing mangrove seedlings. As a result, we conclude that the site is now ready for attempts to rehabilitate the lost mangrove forest.

  11. The Damage To The Armour Layer Due To Extreme Waves

    Science.gov (United States)

    Oztunali Ozbahceci, Berguzar; Ergin, Aysen; Takayama, Tomotsuka

    2010-05-01

    The sea waves are not regular but random and chaotic. In order to understand this randomness, it is common to make individual wave analysis in time domain or spectral analysis in frequency domain. Characteristic wave heights like Hmax, H%2,H1-10, H1-3, Hmean are obtained through individual wave analysis in time domain. These characteristic wave heights are important because they are used in the design of different type of coastal structures. It is common to use significant wave height, H1-3,for the design of rubble mound structures. Therefore, only spectrally derived or zero-crossing significant wave height is usually reported for the rubble mound breakwaters without any information on larger waves. However, even the values of H1-3are similar; some train of irregular waves may exhibit a large fluctuation of instantaneous wave energy, while another train may not show such a fluctuation (Goda, 1998). Moreover, freak or rogue wave, simply defined as the wave exceeding at least twice the significant wave height may also occur. Those larger waves were called as extreme waves in this study and the effect of extreme waves on the damage to the armour layer of rubble mound breakwaters was investigated by means of hydraulic model experiment. Rock armored rubble mound breakwater model with 1:1.5 slope was constructed in the wave channel of Hydraulics Laboratory of the Disaster Prevention Research Institute of Kyoto University, Japan. The model was consisted of a permeable core layer, a filter and armour layer with two stones thicknesses. Size of stones were same for both of the slopes as Dn50(armour)=0.034m, Dn50(filter)=0.021m and Dn50(core)=0.0148m for armour, filter and core layers, respectively. Time series which are approximately equal to 1000 waves, with similar significant wave height but different extreme wave height cases were generated. In order to generate necessary time series in the wave channel, they were firstly computed by numerically. For the numerical

  12. Application of X-Band Wave Radar for Coastal Dynamic Analysis: Case Test of Bagnara Calabra (South Tyrrhenian Sea, Italy

    Directory of Open Access Journals (Sweden)

    Michele Punzo

    2016-01-01

    Full Text Available Sea state knowledge has a key role in evaluation of coastal erosion, the assessment of vulnerability and potential in coastal zone utilization, and development of numerical models to predict its evolution. X-band radar measurements were conducted to observe the spatial and temporal variation of the sea-state parameters along a 3 km long sandy-gravelly pocket beaches forming a littoral cell on Bagnara Calabra. We produced a sequence of 1000 images of the sea state extending offshore up to 1 mile. The survey has allowed monitoring the coastline, the directional wave spectra, the sea surface current fields, and the significant wave heights and detecting strong rip currents which cause scours around the open inlets and affect the stability of the submerged reef-type breakwaters. The possibility to validate the data acquired with other datasets (e.g., LaMMA Consortium demonstrates the potential of the X-band radar technology as a monitoring tool to advance the understanding of the linkages between sea conditions, nearshore sediment dynamics, and coastal change. This work proves the possibility to obtain relevant information (e.g., wave number, period, and direction for evaluation of local erosion phenomena and of morphological changes in the nearshore and surf zone.

  13. Magnetic imaging of a submerged Roman harbour, Caesarea Maritima, Israel

    Science.gov (United States)

    Boyce, J. I.; Reinhardt, E. G.; Raban, A.; Pozza, M. R.

    2003-04-01

    The harbour built by King Herod's engineers at Caesarea represented a major advance in Roman harbour construction that incorporated the use of large (390 m^3), form-filled hydraulic concrete blocks to build an extensive foundation for the harbour moles and breakwater barriers. Marine geophysical surveys were recently conducted across the submerged harbour in an attempt to map the configuration of the buried concrete foundation. A total of 107 line km of high-resolution marine magnetic surveys (nominal 15 m line separations) and bathymetry data were acquired over a 1 km^2 area of the submerged harbour using an Overhauser marine magnetometer, integrated DGPS and single-beam (200 KHz) echosounder. The feasibility of magnetic detection of the concrete was established before the survey by magnetic susceptibility testing of concrete core samples. All concrete samples contained appreciable amounts of fe-oxide-rich volcanic ash ('pozzolana') and showed uniformly high susceptibility values (k > 10^-^4 cgs) when compared to harbour bottom sediments and building stones (k construction of the harbour moles and quays.

  14. Tidal energy conversion. Renewable energy; 3-3 choseki / choryu hatsuden. II. saisei kano energy ni yoru hatsuden

    Energy Technology Data Exchange (ETDEWEB)

    Makino, T. [Tobishima Corp., Tokyo (Japan)

    1998-10-15

    There are not much examples applying tidal energy conversion, but tide and tidal current phenomena can be forecasted so correctly regardless of weather that the applying tidal energy is to be expected in the future. The largest tidal power plant is at Reims in France and install 24 Kaplan turbines each of which outlet power is 10,000kW (rotational direction is reversible) on the breakwater (750m is length). Tidal range at this place being 8.5m on an average, during the period of flowing seawater into the reservoir and on the contrary during the period of discharging seawater to the sea generation is both performed. Though there is no actual result of tidal power plant in Japan, in tidal current power system experimental generators have been installed at Kurushima channel and Naruto channel. Nihon University carried out various kinds of experiment using a Darius turbine (1.6m in dia.) at Kurushima channel and got outlet power of 3kW at the maximum (1983-`88). There are few coasts which have sufficient tide range in Japan, but there are so good many applicable coasts in China and Southeast Asia that the tidal power generation is to be expectatively. 12 refs., 5 figs., 1 tab.

  15. Quantification of midkine gene expression in Patella caerulea (Mollusca, Gastropoda) exposed to cadmium

    Science.gov (United States)

    Stillitano, Francesca; Mugelli, Alessandro; Cerbai, Elisabetta; Vanucci, Silvana

    2007-10-01

    The release of cadmium into many coastal areas represents a threat to ecosystems and human health; cadmium is carcinogenic in mammals and in both marine invertebrates and vertebrates. The use of molluscs to assess the ecologic risk associated with contaminants is strongly recommended on account of their ecological role and on their highly conserved control and regulatory pathways that are often homologous to vertebrate systems. We previously identified a midkine family protein in the limpet Patella caerulea; the midkine is a recently discovered cytokines family with unequivocal informative value on repairing injury and neoplastic processes in mammals. Here we report on midkine ( mdk) and α-tubulin ( α-tub) gene expression patterns in P. caerulea exposed to cadmium. Limpets, collected on two occasions from a breakwater at a marina (Tyrrhenian Sea) were exposed to sublethal cadmium concentrations (0.5 and 1 mg l -1 Cd) over a 10-day exposure period. RNA was extracted from the viscera of unexposed and exposed specimens. Real time TaqMan RT-PCR was performed to measure the relative mdk and α-tub gene expression levels. A remarkable mdk over-expression was observed in all exposed animals with respect to unexposed ones; mdk over-expression was significantly higher in both treatments when compared with un-treatment (mean expression levels: 23- and 38-fold, for 0.5 and 1 mg l -1 Cd treatment, respectively; ANOVA, for both P < 0.01). The study also indicates that the mdk up-regulation was significantly Cd-concentration dependent ( P < 0.05). A significant up-regulation of the constitutive α-tub gene was also observed in 1 mg l -1 Cd-treated animals (mean expression level: 4-fold; ANOVA, P < 0.05). In conclusion, these data provide the first evidence paving the way for the use of the midkine as a promising new biomarker of effect in the environment risk assessment policy.

  16. Coastal monitoring through video systems: best practices and architectural design of a new video monitoring station in Jesolo (Veneto, Italy)

    Science.gov (United States)

    Archetti, Renata; Vacchi, Matteo; Carniel, Sandro; Benetazzo, Alvise

    2013-04-01

    Measuring the location of the shoreline and monitoring foreshore changes through time represent a fundamental task for correct coastal management at many sites around the world. Several authors demonstrated video systems to be an essential tool for increasing the amount of data available for coastline management. These systems typically sample at least once per hour and can provide long-term datasets showing variations over days, events, months, seasons and years. In the past few years, due to the wide diffusion of video cameras at relatively low price, the use of video cameras and of video images analysis for environmental control has increased significantly. Even if video monitoring systems were often used in the research field they are most often applied with practical purposes including: i) identification and quantification of shoreline erosion, ii) assessment of coastal protection structure and/or beach nourishment performance, and iii) basic input to engineering design in the coastal zone iv) support for integrated numerical model validation Here we present the guidelines for the creation of a new video monitoring network in the proximity of the Jesolo beach (NW of the Adriatic Sea, Italy), Within this 10 km-long tourist district several engineering structures have been built in recent years, with the aim of solving urgent local erosion problems; as a result, almost all types of protection structures are present at this site: groynes, detached breakwaters.The area investigated experienced severe problems of coastal erosion in the past decades, inclusding a major one in the last November 2012. The activity is planned within the framework of the RITMARE project, that is also including other monitoring and scientific activities (bathymetry survey, waves and currents measurements, hydrodynamics and morphodynamic modeling). This contribution focuses on best practices to be adopted in the creation of the video monitoring system, and briefly describes the

  17. A geological perspective on the degradation and conservation of western Atlantic coral reefs.

    Science.gov (United States)

    Kuffner, Ilsa B; Toth, Lauren T

    2016-08-01

    Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs-as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species-cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of resources

  18. Changes in the shoreline at Paradip Port, India in response to climate change

    Science.gov (United States)

    Gopikrishna, B.; Deo, M. C.

    2018-02-01

    One of the popular methods to predict shoreline shifts into the future involves use of a shoreline evolution model driven by the historical wave climate. It is however understood by now that historical wave conditions might substantially change in future in response to climate change induced by the global warming. The future shoreline changes as well as sediment transport therefore need to be determined with the help of future projections of wave climate. In this work this is done at the port of Paradip situated along the east coast of India. The high resolution wind resulting from a climate modelling experiment called: CORDEX, South Asia, was used to simulate waves over two time-slices of 25 years each in past and future. The wave simulations were carried out with the help of a numerical wave model. Thereafter, rates of longshore sediment transport as well as shoreline shifts were determined over past and future using a numerical shoreline model. It was found that at Paradip Port the net littoral drift per metre width of cross-shore might go up by 37% and so also the net accumulated drift over the entire cross-shore width by 71%. This could be caused by an increase in the mean significant wave height of around 32% and also by changes in the frequency and direction of waves. The intensification of waves in turn might result from an increase in the mean wind speed of around 19%. Similarly, the horizontal extent of the beach accretion and erosion at the port's southern breakwater might go up by 4 m and 8 m, respectively, from the current level in another 25 years. This study should be useful in framing future port management strategies.

  19. The beneficial role of rubble mound coastal structures on seawater oxygenation

    Directory of Open Access Journals (Sweden)

    E. I. Daniil

    2000-10-01

    Full Text Available The beneficial role of rubble mound coastal structures on oxygenation under the effect of waves is discussed, based on analytical considerations and experimental data from laboratory experiments with permeable and impermeable structures. Significant oxygenation of the wave-protected area was observed as a result of horizontal transport through the permeable structure. A two-cell model describing the transport of dissolved oxygen (DO near a rubble mound breakwater structure was developed and used for the determination of the oxygen transfer coefficients from the experimental data. Oxygen transfer through the air–water interface is considered a source term in the transport equation and the oxygen flux through the structure is taken into account. The mass transport equations for both sides of the structure are solved analytically in terms of time evolution of DO concentration. The behaviour of the solution is illustrated for three different characteristic cases of initial conditions. The oxygen transfer through the air-water interface in the wave-influenced area increases the DO content in the area; the resulting oxygen flux through the structure is discussed. The analytical results depend on the initial conditions, the oxygen transfer coefficient and the exchange flow rate through the structure. Experiments with impermeable structures show that air water oxygen transfer in the harbour area is negligible in the absence of waves. In addition the ratio of the horizontal DO flux to the vertical flux into the seaward side tends towards a constant value, independent of the initial conditions.Key words: Oceanography: physical (air-sea interactions; surface waves and tides

  20. Anthropogenic disturbance can determine the magnitude of opportunistic species responses on marine urban infrastructures.

    Directory of Open Access Journals (Sweden)

    Laura Airoldi

    Full Text Available BACKGROUND: Coastal landscapes are being transformed as a consequence of the increasing demand for infrastructures to sustain residential, commercial and tourist activities. Thus, intertidal and shallow marine habitats are largely being replaced by a variety of artificial substrata (e.g. breakwaters, seawalls, jetties. Understanding the ecological functioning of these artificial habitats is key to planning their design and management, in order to minimise their impacts and to improve their potential to contribute to marine biodiversity and ecosystem functioning. Nonetheless, little effort has been made to assess the role of human disturbances in shaping the structure of assemblages on marine artificial infrastructures. We tested the hypothesis that some negative impacts associated with the expansion of opportunistic and invasive species on urban infrastructures can be related to the severe human disturbances that are typical of these environments, such as those from maintenance and renovation works. METHODOLOGY/PRINCIPAL FINDINGS: Maintenance caused a marked decrease in the cover of dominant space occupiers, such as mussels and oysters, and a significant enhancement of opportunistic and invasive forms, such as biofilm and macroalgae. These effects were particularly pronounced on sheltered substrata compared to exposed substrata. Experimental application of the disturbance in winter reduced the magnitude of the impacts compared to application in spring or summer. We use these results to identify possible management strategies to inform the improvement of the ecological value of artificial marine infrastructures. CONCLUSIONS/SIGNIFICANCE: We demonstrate that some of the impacts of globally expanding marine urban infrastructures, such as those related to the spread of opportunistic, and invasive species could be mitigated through ecologically-driven planning and management of long-term maintenance of these structures. Impact mitigation is a

  1. The unexpected response of kelp to wave motion

    Science.gov (United States)

    Mullarney, J. C.; Pilditch, C. A.

    2014-12-01

    Kelp ecosystems offer many ecosystem services such as providing critical habitat for numerous species, trapping contaminants and nutrients and influencing coastal morphology. However, the extent to which kelp 'goes with the flow' as opposed to dissipating wave and current energy is unclear. We present innovative measurements of the wave-forced motion of the giant kelp Macrocystis pyrifera at different heights along the length of the stipe using a series of accelerometers attached at fixed intervals. Observations were taken at the Aramoana breakwater ("the Mole"), located at the entrance to Otago Harbor, New Zealand. This field site encompassed a wave-exposed region open to Pacific swells and a sheltered (harbor) region. Analysis of wave gauge measurements revealed that forcing was dominated by the swell frequency (0.11 Hz). However, the spectra also indicated periods of substantial energy at lower, infragravity wave frequencies (0.011 Hz). Preliminary analysis of the accelerometer data shows significant differences in displacement over the stem length, with large motions apparent at both the top and bottom of the kelp (consistent with visual observations from divers). Initial observations also revealed an unexpected result; different sections of the kelp responded most strongly to different forcing frequencies. In particular, the lowest sensor showed peaks in energy close to both swell and infragravity periods, whereas the higher sensor revealed the surprising result of a strong response at the infragravity frequencies but little movement at the swell frequencies. We discuss how these results may allow us to determine the extent to which aquatic plants are adapted to minimize stresses imposed by fluid flow and potential consequences for present and future plant community distributions.

  2. Modelling of sediment transport and morphological evolution under the combined action of waves and currents

    Directory of Open Access Journals (Sweden)

    G. Franz

    2017-09-01

    Full Text Available Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH, which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

  3. Maintaining a way of life for São Miguel Island (the Azores archipelago, Portugal): an assessment of coastal processes and protection.

    Science.gov (United States)

    Ng, K; Phillips, M R; Borges, P; Thomas, T; August, P; Calado, H; Veloso-Gomes, F

    2014-05-15

    Traditional hard engineering structures and recently emerging soft engineering alternatives have been employed to protect vulnerable coastlines. Despite negative publicity, they have ensured community survival where socio-economic benefits outweigh adverse impacts. This is especially true for Small Islands (SI) where increasing sea levels and storm intensities threaten already limited land availability. This paper presents coastal vulnerability in São Miguel Island (the Azores SI archipelago) and considers SI issues with regard to coastal land loss. Regional wave statistics using 1998 to 2011 wind record showed: periods ranging from 7 to 13s (circa 83%); wave heights between 1 and 3m (circa 60%); and increasing trends in westerly (p=0.473), easterly (p=0.632) and southeasterly (p=0.932) waves. Sea level analyses between 1978 and 2007 indicated a statistically significant rising trend (2.5 ± 0.4 mm yr(-1); p=0.000), while between 1996 and 2007 it was 3.3 ± 1.5 mm yr(-1) (p=0.025), agreeing with other global sea level studies. Based on 2001 and 2008 population data and using zonal statistics, circa 60% of the Island's population was found to reside within 1 km of the sea and the percentage of total population was linearly correlated with distance from the shoreline (r(2)=99%). Three case studies show hard coastal engineering solutions preserved Azorean coastal lifestyle and had little or no observed negative impacts on their environs. Although hard engineering is likely to remain a valuable and feasible coastal protection option, an inventory of São Miguel's population distribution, surf breaks, bathymetry and coastal erosion rates showed the potential of using multifunctional artificial reefs as a soft engineering solution. These offshore submerged breakwaters offer coastal protection while providing additional benefits such as surfing amenity and beach widening. Consequently, findings of this work can inform other SI communities. Copyright © 2014 Elsevier B

  4. Beamline 12.3.2 at the Advanced Light Source: direct strain measurements and micron-scale phase maps

    Science.gov (United States)

    Stan, C. V.; Tamura, N.; Wenk, H. R.; Jackson, M. D.

    2016-12-01

    Analytical techniques implemented at the microdiffraction beamline 12.3.2 of the Advanced Light Source (ALS) provide valuable and innovative support for mineral investigations in the geoscience community. We have developed angular (ADXRD) and energy (Laue) dispersive diffraction techniques coupled with elemental identification using parallel x-ray fluorescence (XRF) compositional analysis. Here, we present two recent applications specific to the fields of mineralogy and petrology. The first application is the characterization of residual strain state in boudins collected from Bastogne, Belgium, demonstrating the use of Laue diffraction ( 1 μm x-ray beam spot diameter) as a measure of rock deformation. Measurement of the residual lattice strain in layer-perpendicular quartz crystals (30-800 μm grain size) indicates that elastic shortening occurs perpendicular to the vein walls irrespective of the quartz grain size or orientation. This cohesive signal shows that boudins formed through layer-parallel shortening, a finding that would not have been possible using standard diffraction equipment. In the second application, ADXRD (2 x 5 μm x-ray beam spot size) is coupled with XRF to create point-to-point mineral maps with μm-scale spacing of cementitious microstructures in both 2000-year-old Roman harbor concrete (Baianus Sinus breakwater, Bay of Pozzuoli, Italy) and Campi Flegrei pumice clasts. We find that Al-tobermorite, a rare layered Ca-Si hydrate mineral, crystallized through pozzolanic processes in association with ettringite and hydrocalumite in relict lime clasts, and through post-pozzolanic, diagenetic processes in association with phillipsite in adjacent pumice clasts. The results provide new insights into developing environmentally-friendly concretes using seawater and into the formation of natural volcanic rock aggregates. The techniques available at beamline 12.3.2 have the potential to address a wide range of research topics within the geoscience

  5. California Shoreline Sand Retention: Existing Structure Performance and Future Potential

    Science.gov (United States)

    Kinsman, N. E.; Griggs, G. B.

    2008-12-01

    Amidst rising sea level, climate change and expanding coastal populations, sandy beaches are frequently exposed to erosional processes. Effective sea level rise will lead to recreational beach loss as a result of coastal inundation. Beach nourishment is growing in popularity as a mitigation approach to meet the increasing need to protect coastal resources. The practice of beach nourishment along high energy shorelines, such as in California, is often improved by the construction of sediment retention structures (groins) to enhance project lifespans. However, our current ability to design effective littoral barriers is extremely limited. An underutilized and cost-effective resource for critically analyzing engineered retention structure performance is the record of existing structures within California. The impacts of 205 structures along California's 1700 km shoreline have been systematically explored though measurements collected from aerial imagery and historic shoreline positions. The findings of this study suggest that approximately 30 million m3 of sand and 18% of California's total exposed sandy beach area is presently retained in fillet and salient beaches associated with man-made structures such as groins, breakwaters, piers and jetties. Preliminary results suggest statistically significant correlations between structure effectiveness and key characteristics such as orientation, littoral cell position and construction materials. The central product of this study is a complete and robust GIS catalog of retention structures along California's coastline. A detailed analysis of historic structure performance combined with a systematically measured record of structure characteristics for the entire state results in a useful product to help coastal planners use the lessons of the past to plan future beach management.

  6. A comparative study of diffraction of shallow-water waves by high-level IGN and GN equations

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, B.B. [College of Shipbuilding Engineering, Harbin Engineering University, 150001 Harbin (China); Ertekin, R.C. [Department of Ocean and Resources Engineering, University of Hawai' i, Honolulu, HI 96822 (United States); College of Shipbuilding Engineering, Harbin Engineering University, 150001 Harbin (China); Duan, W.Y., E-mail: duanwenyangheu@hotmail.com [College of Shipbuilding Engineering, Harbin Engineering University, 150001 Harbin (China)

    2015-02-15

    This work is on the nonlinear diffraction analysis of shallow-water waves, impinging on submerged obstacles, by two related theories, namely the classical Green–Naghdi (GN) equations and the Irrotational Green–Naghdi (IGN) equations, both sets of equations being at high levels and derived for incompressible and inviscid flows. Recently, the high-level Green–Naghdi equations have been applied to some wave transformation problems. The high-level IGN equations have also been used in the last decade to study certain wave propagation problems. However, past works on these theories used different numerical methods to solve these nonlinear and unsteady sets of differential equations and at different levels. Moreover, different physical problems have been solved in the past. Therefore, it has not been possible to understand the differences produced by these two sets of theories and their range of applicability so far. We are thus motivated to make a direct comparison of the results produced by these theories by use of the same numerical method to solve physically the same wave diffraction problems. We focus on comparing these two theories by using similar codes; only the equations used are different but other parts of the codes, such as the wave-maker, damping zone, discretion method, matrix solver, etc., are exactly the same. This way, we eliminate many potential sources of differences that could be produced by the solution of different equations. The physical problems include the presence of various submerged obstacles that can be used for example as breakwaters or to represent the continental shelf. A numerical wave tank is created by placing a wavemaker on one end and a wave absorbing beach on the other. The nonlinear and unsteady sets of differential equations are solved by the finite-difference method. The results are compared with different equations as well as with the available experimental data.

  7. Modelling of sediment transport and morphological evolution under the combined action of waves and currents

    Science.gov (United States)

    Franz, Guilherme; Delpey, Matthias T.; Brito, David; Pinto, Lígia; Leitão, Paulo; Neves, Ramiro

    2017-09-01

    Coastal defence structures are often constructed to prevent beach erosion. However, poorly designed structures may cause serious erosion problems in the downdrift direction. Morphological models are useful tools to predict such impacts and assess the efficiency of defence structures for different scenarios. Nevertheless, morphological modelling is still a topic under intense research effort. The processes simulated by a morphological model depend on model complexity. For instance, undertow currents are neglected in coastal area models (2DH), which is a limitation for simulating the evolution of beach profiles for long periods. Model limitations are generally overcome by predefining invariant equilibrium profiles that are allowed to shift offshore or onshore. A more flexible approach is described in this paper, which can be generalised to 3-D models. The present work is based on the coupling of the MOHID modelling system and the SWAN wave model. The impacts of different designs of detached breakwaters and groynes were simulated in a schematic beach configuration following a 2DH approach. The results of bathymetry evolution are in agreement with the patterns found in the literature for several existing structures. The model was also tested in a 3-D test case to simulate the formation of sandbars by undertow currents. The findings of this work confirmed the applicability of the MOHID modelling system to study sediment transport and morphological changes in coastal zones under the combined action of waves and currents. The same modelling methodology was applied to a coastal zone (Costa da Caparica) located at the mouth of a mesotidal estuary (Tagus Estuary, Portugal) to evaluate the hydrodynamics and sediment transport both in calm water conditions and during events of highly energetic waves. The MOHID code is available in the GitHub repository.

  8. Geomorphic factors related to the persistence of subsurface oil from the Exxon Valdez oil spill

    Science.gov (United States)

    Nixon, Zachary; Michel, Jacqueline; Hayes, Miles O.; Irvine, Gail V.; Short, Jeffrey

    2013-01-01

    Oil from the 1989 Exxon Valdez oil spill has persisted along shorelines of Prince William Sound, Alaska, for more than two decades as both surface and subsurface oil residues. To better understand the distribution of persistent subsurface oil and assess the potential need for further restoration, a thorough and quantitative understanding of the geomorphic factors controlling the presence or absence of subsurface oil is required. Data on oiling and geomorphic features were collected at 198 sites in Prince William Sound to identify and quantify the relationships among these geomorphic factors and the presence and absence of persistent subsurface oil. Geomorphic factors associated with the presence of subsurface oil were initial oil exposure, substrate permeability, topographic slope, low exposure to waves, armoring on gravel beaches, tombolos, natural breakwaters, and rubble accumulations. Geomorphic factors associated with the absence of subsurface oil were impermeable bedrock; platforms with thin sediment veneer; fine-grained, well-sorted gravel beaches with no armor; and low-permeability, raised bay-bottom beaches. Relationships were found between the geomorphic and physical site characteristics and the likelihood of encountering persistent subsurface oiling at those sites. There is quantitative evidence of more complex interactions between the overall wave energy incident at a site and the presence of fine-scale geomorphic features that may have provided smaller, local wave energy sheltering of oil. Similarly, these data provide evidence for interactions between the shoreline slope and the presence of angular rubble, with decreased likelihood for encountering subsurface oil at steeply sloped sites except at high-angle sheltered rubble shoreline locations. These results reinforce the idea that the interactions of beach permeability, stability, and site-specific wave exposure are key drivers for subsurface oil persistence in exposed and intermittently exposed mixed

  9. Balancing Power Absorption and Structural Loading for an Assymmetric Heave Wave-Energy Converter in Regular Waves: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M.; Madhi, Farshad; Yeung, Ronald W.

    2016-07-01

    The aim of this paper is to maximize the power-to-load ratio of the Berkeley Wedge: a one-degree-of-freedom, asymmetrical, energy-capturing, floating breakwater of high performance that is relatively free of viscosity effects. Linear hydrodynamic theory was used to calculate bounds on the expected time-averaged power (TAP) and corresponding surge restraining force, pitch restraining torque, and power take-off (PTO) control force when assuming that the heave motion of the wave energy converter remains sinusoidal. This particular device was documented to be an almost-perfect absorber if one-degree-of-freedom motion is maintained. The success of such or similar future wave energy converter technologies would require the development of control strategies that can adapt device performance to maximize energy generation in operational conditions while mitigating hydrodynamic loads in extreme waves to reduce the structural mass and overall cost. This paper formulates the optimal control problem to incorporate metrics that provide a measure of the surge restraining force, pitch restraining torque, and PTO control force. The optimizer must now handle an objective function with competing terms in an attempt to maximize power capture while minimizing structural and actuator loads. A penalty weight is placed on the surge restraining force, pitch restraining torque, and PTO actuation force, thereby allowing the control focus to be placed either on power absorption or load mitigation. Thus, in achieving these goals, a per-unit gain in TAP would not lead to a greater per-unit demand in structural strength, hence yielding a favorable benefit-to-cost ratio. Demonstrative results in the form of TAP, reactive TAP, and the amplitudes of the surge restraining force, pitch restraining torque, and PTO control force are shown for the Berkeley Wedge example.

  10. Growth Rate of Acropora formosa Fragments that Transplanted on Artificial Substrate Made from Coral Rubble

    Directory of Open Access Journals (Sweden)

    NUR FADLI

    2009-10-01

    Full Text Available Coral reefs play an important physiological and ecological role in coastal ecosystems such as providing natural breakwaters that protect shorelines and human settlements from waves and storm. Corals killed by tsunami, waves and storms are often degraded into rubble. This rubble is dynamic, easily shifted by currents and storms, which effectively forms ‘‘killing fields’’ for coral juveniles, hindering coral recovery. In order to rehabilitate coral reefs, artificial substrates are used both for coral transplantation and recruitment. Unfortunately, most artificial substrates are expensive and use land-based material such as concrete/cement-bases. In order to develop a new low-cost artificial substrate that can replace concrete/cement-base as a media for coral transplantation, modified coral rubble was tested in a pilot study in Seribu Island, Jakarta. Two different nets (nylon and polyethylene were used to form rubble into a compact shape, stable and strong substrate. The stability of the rubble and the complexity of the surface which is created by the net make this substrate suitable for coral transplantation. Additionally, from an economic perspective the nets are very cheap and locally available. In a number of experiments, modified coral rubble successfully replaced the concrete/cement-base as a media for coral transplantation. The coral transplants were growing over time. With this method, we can try to rehabilitate the degraded coral reef destroyed by tsunami or other factors with material that already is available at the site and with less money. However, this approach requires testing at additional sites and for longer periods, to determine the replicability of the results.

  11. Seagrasses and sediment response to the changing physical forcing in a coastal lagoon

    Science.gov (United States)

    Figueiredo da Silva, J.; Duck, R. W.; Pereira, M. J.; Catarino, J. B.

    2003-04-01

    The Ria de Aveiro is an estuary - coastal lagoon system connected to the Atlantic Ocean by a channel with a cross-sectional area that has steadily increased over more than one century. Local ocean tides, with amplitudes of 1-3 m, are today transmitted to the lagoon by the single, engineered inlet channel and propagate to the end of the lagoon channels as a damped progressive wave. The natural channel connecting the lagoon to the ocean evolved during historical times, moving southward and reducing its cross-section. The natural evolution was reverted in 1808 by opening the new inlet channel that has since been protected by breakwaters and deepened by dredging. This controlled evolution has caused an increase in the tidal prism associated with a larger tidal oscillation inside the lagoon. The change in tidal amplitude has important effects on the lagoon ecosystem, which are related to the increase in tidal currents, water level and salinity of the water. The pollution load reaching the lagoon from its catchment area is now, however, more readily flushed to the ocean. Most affected by the change are mudflat and intertidal areas, including the old salt-pans, some showing signs of erosion while others accumulate sediment that is transported in suspension by the strong tidal currents. Important indicators of ecosystem change are the seagrass beds. Until 1980 large areas of the lagoon bed were covered by seagrasses (Zostera, Ruppia, Potamogeton), which were collected in large quantities for use in agriculture. After 1980, the collection declined and the seagrass beds became sediment-covered. This resulted in a large decrease in the area of seagrasses in spite of the decline in the quantity collected. Our results show a pattern in the change of the seagrass populations that can be related to the changes in the physical forcing associated with tidal wave propagation. A parallel change in sediment texture was also observed.

  12. A geological perspective on the degradation and conservation of western Atlantic coral reefs

    Science.gov (United States)

    Kuffner, Ilsa B.; Toth, Lauren T.

    2016-01-01

    Continuing coral-reef degradation in the western Atlantic is resulting in loss of ecological and geologic functions of reefs. With the goal of assisting resource managers and stewards of reefs in setting and measuring progress toward realistic goals for coral-reef conservation and restoration, we examined reef degradation in this region from a geological perspective. The importance of ecosystem services provided by coral reefs—as breakwaters that dissipate wave energy and protect shorelines and as providers of habitat for innumerable species—cannot be overstated. However, the few coral species responsible for reef building in the western Atlantic during the last approximately 1.5 million years are not thriving in the 21st century. These species are highly sensitive to abrupt temperature extremes, prone to disease infection, and have low sexual reproductive potential. Their vulnerability and the low functional redundancy of branching corals have led to the low resilience of western Atlantic reef ecosystems. The decrease in live coral cover over the last 50 years highlights the need for study of relict (senescent) reefs, which, from the perspective of coastline protection and habitat structure, may be just as important to conserve as the living coral veneer. Research is needed to characterize the geological processes of bioerosion, reef cementation, and sediment transport as they relate to modern-day changes in reef elevation. For example, although parrotfish remove nuisance macroalgae, possibly promoting coral recruitment, they will not save Atlantic reefs from geological degradation. In fact, these fish are quickly nibbling away significant quantities of Holocene reef framework. The question of how different biota covering dead reefs affect framework resistance to biological and physical erosion needs to be addressed. Monitoring and managing reefs with respect to physical resilience, in addition to ecological resilience, could optimize the expenditure of

  13. Comparison of Laboratory Experimental Data to XBeach Numerical Model Output

    Science.gov (United States)

    Demirci, Ebru; Baykal, Cuneyt; Guler, Isikhan; Sogut, Erdinc

    2016-04-01

    generating data sets for testing and validation of sediment transport relationships for sand transport in the presence of waves and currents. In these series, there is no structure in the basin. The second and third series of experiments were designed to generate data sets for development of tombolos in the lee of detached 4m-long rubble mound breakwater that is 4 m from the initial shoreline. The fourth series of experiments are conducted to investigate tombolo development in the lee of a 4m-long T-head groin with the head section in the same location of the second and the third tests. The fifth series of experiments are used to investigate tombolo development in the lee of a 3-m-long rubble-mound breakwater positioned 1.5 m offshore of the initial shoreline. In this study, the data collected from the above mentioned five experiments are used to compare the results of the experimental data with XBeach numerical model results, both for the "no-structure" and "with-structure" cases regarding to sediment transport relationships in the presence of only waves and currents as well as the shoreline changes together with the detached breakwater and the T-groin. The main purpose is to investigate the similarities and differences between the laboratory experimental data behavior with XBeach numerical model outputs for these five cases. References: Baykal, C., Sogut, E., Ergin, A., Guler, I., Ozyurt, G.T., Guler, G., and Dogan, G.G. (2015). Modelling Long Term Morphological Changes with XBeach: Case Study of Kızılırmak River Mouth, Turkey, European Geosciences Union, General Assembly 2015, Vienna, Austria, 12-17 April 2015. Gravens, M.B. and Wang, P. (2007). "Data report: Laboratory testing of longshore sand transport by waves and currents; morphology change behind headland structures." Technical Report, ERDC/CHL TR-07-8, Coastal and Hydraulics Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS. Roelvink, D., Reniers, A., van Dongeren, A., van Thiel de

  14. Integrated protecting plan for beach erosion. A case study in Plaka beach, E. Crete, Greece

    Science.gov (United States)

    Petrakis, Stelios; Alexandrakis, George; Kozyrakis, George; Hatziyanni, Eleni; Kampanis, Nikolaos

    2015-04-01

    Coastal zones are among the most active areas on Earth, being subjected to extreme wind / wave conditions, thus vulnerable to erosion. In Greece and Crete in particular, beach zones are extremely important for the welfare of the inhabitants, since, apart for the important biological and archaeological value of the beach zones, the socio-economic value is critical since a great number of human activities are concentrated in such areas (touristic facilities, fishing harbors etc.). The present study investigates the erosional procedures observed in Plaka beach, E. Crete, Greece, a highly touristic developed area with great archaeological interest and proposes a cost-effective solution. The factors taken into consideration for the proposed solution in reducing the erosion of the beach were the study of the climatological, geological and geomorphological regime of the area, the recent (~70 years) shifting of the coastline through the study of topographic maps, aerial photographs and satellite images, the creation of detailed bathymetric and seabed classification maps of the area and finally, a risk analysis in terms of erosional phenomena. On the basis of the above, it is concluded that the area under investigation is subjected to an erosional rate of about 1 m/10 years and the total land-loss for the past 70 years is about 4600 m2. Through the simulation of the wave regime we studied 3 possible scenarios, the "do-nothing" scenario, the construction of a detached submerged breakwater at the depth of 3 meters and, finally, the armoring of the existing beach-wall through the placement of appropriate size and material boulders, forming an artificial slope for the reducing of the wave breaking energy and a small scale nourishment plan. As a result, through the modeling of the above, the most appropriate and cost-effective solution was found to be the third, armoring of the existing coastal wall and nourishment of the beach periodically, thus the further undermining of the

  15. Unlocking the secrets of Al-tobermorite in Roman seawater concrete

    KAUST Repository

    Jackson, Marie D.

    2013-10-01

    Ancient Roman syntheses of Al-tobermorite in a 2000-year-old concrete block submerged in the Bay of Pozzuoli (Baianus Sinus), near Naples, have unique aluminum-rich and silica-poor compositions relative to hydrothermal geological occurrences. In relict lime clasts, the crystals have calcium contents that are similar to ideal tobermorite, 33 to 35 wt%, but the low-silica contents, 39 to 40 wt%, reflect Al3+ substitution for Si4+ in Q 2(1Al), Q3(1Al), and Q3(2 Al) tetrahedral chain and branching sites. The Al-tobermorite has a double silicate chain structure with long chain lengths in the b [020] crystallographic direction, and wide interlayer spacing, 11.49 Å. Na+ and K+ partially balance Al3+ substitution for Si4+. Poorly crystalline calcium-aluminum-silicate-hydrate (C-A-S-H) cementitious binder in the dissolved perimeter of relict lime clasts has Ca/(Si+Al) = 0.79, nearly identical to the Al-tobermorite, but nanoscale heterogeneities with aluminum in both tetrahedral and octahedral coordination. The concrete is about 45 vol% glassy zeolitic tuff and 55 vol% hydrated lime-volcanic ash mortar; lime formed <10 wt% of the mix. Trace element studies confirm that the pyroclastic rock comes from Flegrean Fields volcanic district, as described in ancient Roman texts. An adiabatic thermal model of the 10 m2 by 5.7 m thick Baianus Sinus breakwater from heat evolved through hydration of lime and formation of C-A-S-H suggests maximum temperatures of 85 to 97 °C. Cooling to seawater temperatures occurred in two years. These elevated temperatures and the mineralizing effects of sea-water and alkali- and alumina-rich volcanic ash appear to be critical to Al-tobermorite crystallization. The long-term stability of the Al-tobermorite provides a valuable context to improve future syntheses in innovative concretes with advanced properties using volcanic pozzolans.

  16. Tales of some ancient harbors in the Aegean back-arc region: Earthquakes, coastal changes, historical impacts

    Science.gov (United States)

    Stiros, Stathis; Saltogianni, Vasso

    2017-04-01

    this ancient town since approximately AD200 as a result of loss of the only significant harbor along the southern coast of the Gulf of Corinth. Farther west, in the south part of the Greek mainland, rising of the level of the dock shortly after its construction may imply response to seismic land subsidence, while at the nearby harbor of Palairos, remains of a submerged breakwater, offset by several meters, testify to strike slip faulting with seismic offset amplified by liquefaction.

  17. Time Evolution of Man-Made Harbour Modifications in San Diego: Effects on Tsunami Amplitudes and Currents

    Science.gov (United States)

    Barberopoulou, A.; Legg, M.; Gica, E.

    2014-12-01

    Harbors are typically modified to enhance operations and increase space in ports. Ports are usually designed to protect boats and docks against sudden vertical water fluctuations. Tsunami currents however are often ignored-current monitoring is usually not quantitative- in the design of harbor modifications. Damage from tsunami currents in ports has occurred in several recent tsunamis (Sea of Japan, 1983; Chile, 1960, 2010; Tohoku, 2011). Significant tsunami currents (>2 m/sec) often occur without substantial wave amplitudes (event "significance", the hazard from potentially strong currents may be overlooked. In order to evaluate the impact of anthropogenic effects on tsunami impact at ports, we examine the history of man-made modifications made to San Diego Bay since the late nineteenth century. Digital elevation models were created based on historic nautical charts of 1892, 1935, 1945 and at present. Tsunami simulations were conducted based on two distant events (1960 Chile and 2011 Tohoku) and two hypothetical severe local cases (San Clemente fault bend and Coronado Canyon landslide). The distant events provide historical comparisons with the model while the local events are based on offshore geology and tectonic activity. Most of the changes in San Diego Bay have included dredging, enlargement of the North Island/Coronado, widening of the Silver Strand, and creation of new marinas by enhancing already existing dunes or filling and creating breakwaters. Those changes mostly occurred during the first half of the 20th century. Post- 1965 the bay has sustained a similar appearance to the bathymetry/topography we know today. Early harbor configurations showed strong currents in the narrow channel between Point Loma and North Island/Coronado while overtopping of the narrow Silver Strand to the south occurred. The modern configuration finds increased currents at the harbor entrance and between Coronado and downtown San Diego, where the channel has been narrowed, while

  18. Wave-induced current considering wave-tide interaction in Haeundae

    Science.gov (United States)

    Lim, Hak Soo

    2017-04-01

    The Haeundae, located at the south eastern end of the Korean Peninsula, is a famous beach, which has an approximately 1.6 km long and 70 m wide coastline. The beach has been repeatedly eroded by the swell waves caused by typhoons in summer and high waves originating in the East Sea in winter. The Korean government conducted beach restoration projects including beach nourishment (620,000 m3) and construction of two submerged breakwaters near both ends of the beach. To prevent the beach erosion and to support the beach restoration project, the Korean government initiated a R&D project, the development of coastal erosion control technology since 2013. As a part of the project, we have been measuring waves and currents at a water depth of 22 m, 1.8 km away from the beach using an acoustic wave and current meter (AWAC) continuously for more than three years; we have also measured waves and currents intensively near the surf-zone in summer and winter. In this study, a numerical simulation using a wave and current coupled model (ROMS-SWAN) was conducted for determining the wave-induced current considering seasonal swell waves (Hs : 2.5 m, Tp: 12 s) and for better understanding of the coastal process near the surf-zone in Haeundae. By comparing the measured and simulated results, we found that cross-shore current during summer is mainly caused by the eddy produced by the wave-induced current near the beach, which in turn, is generated by the strong waves coming from the SSW and S directions. During other seasons, longshore wave-induced current is produced by the swell waves coming from the E and ESE directions. The longshore current heading west toward Dong-Back Island, west end of the beach, during all the seasons and eddy current toward Mipo-Port, east end of the beach, in summer which is well matched with the observed residual current. The wave-induced current with long-term measurement data is incorporated in simulation of sediment transport modeling for developing

  19. Monitoring Coastal Processes at Local and Regional Geographic Scales with UAS

    Science.gov (United States)

    Starek, M. J.; Bridges, D.; Prouty, D.; Berryhill, J.; Williams, D.; Jeffress, G.

    2014-12-01

    Unmanned Aerial Systems (UAS) provide a powerful tool for coastal mapping due to attractive features such as low cost data acquisition, flexibility in data capture and resolution, rapid response, and autonomous flight. We investigate two different scales of UAS platforms for monitoring coastal processes along the central Texas Gulf coast. Firstly, the eBee is a small-scale UAS weighing ~0.7 kg designed for localized mapping. The imaging payload consists of a hand held RGB digital camera and NIR digital camera, both with 16.1 megapixel resolutions. The system can map up to 10 square kilometers on a single flight and is capable of acquiring imagery down to 1.5 cm ground sample distance. The eBee is configured with a GPS receiver, altitude sensor, gyroscope and a radio transmitter enabling autonomous flight. The system has a certificate of authorization (COA) from the FAA to fly over the Ward Island campus of Texas A&M University-Corpus Christi (TAMUCC). The campus has an engineered beach, called University Beach, located along Corpus Christi Bay. A set of groins and detached breakwaters were built in an effort to protect the beach from erosive wave action. The eBee is being applied to periodically survey the beach (Figure 1A). Through Structure from Motion (SfM) techniques, eBee-derived image sequences are post-processed to extract 3D topography and measure volumetric change. Additionally, when water clarity suffices, this approach enables the extraction of shallow-water bathymetry. Results on the utilization of the eBee to monitor beach morphodynamics will be presented including a comparison of derived estimates to RTK GPS and airborne lidar. Secondly, the RS-16 UAS has a 4 m wingspan and 11 kg sensor payload. The system is remotely piloted and has a flight endurance of 12 to 16 hours making it suitable for regional scale coastal mapping. The imaging payload consists of a multispectral sensor suite measuring in the visible, thermal IR, and ultraviolet ranges of the

  20. Ecological Effects of Sea Level Rise: Advancing coastal management through integrated research and engagement

    Science.gov (United States)

    Kidwell, D. M.

    2012-12-01

    Rising sea level represents a significant threat to coastal communities and ecosystems through land loss, altered habitats, and increased vulnerability to coastal storms and inundation. This threat is exemplified in the northern Gulf of Mexico where low topography, expansive marshes, and a prevalence of tropical storms have already resulted in extensive coastal impacts. The development of robust predictive capabilities that incorporate complex biological processes with physical dynamics are critical for informed planning and restoration efforts for coastal ecosystems. Looking to build upon existing predictive modeling capabilities and allow for use of multiple model (i.e., ensemble) approaches, NOAA initiated the Ecological Effects of Sea Level Rise program in 2010 to advance physical/biological integrative modeling capabilities in the region with a goal to provide user friendly predictive tools for coastal ecosystem management. Focused on the northern Gulf of Mexico, this multi-disciplinary project led by the University of Central Florida will use in situ field studies to parameterize physical and biological models. These field studies will also result in a predictive capability for overland sediment delivery and transport that will further enhance marsh, oyster, and submerged aquatic vegetation models. Results from this integrated modeling effort are envisioned to inform management strategies for reducing risk, restoration and breakwater guidelines, and resource sustainability for project planning, among other uses. In addition to the science components, this project incorporates significant engagement of the management community through a management applications principle investigator and an advisory management committee. Routine engagement between the science team and the management committee, including annual workshops, are focused on ensuring the development of applicable, relevant, and useable products and tools at the conclusion of this project. Particular

  1. Integrated Modeling for the Assessment of Ecological Impacts of Sea Level Rise

    Science.gov (United States)

    Hagen, S. C.; Lewis, G.; Bartel, R.; Batten, B.; Huang, W.; Morris, J.; Slinn, D. N.; Sparks, J.; Walters, L.; Wang, D.; Weishampel, J.; Yeh, G.

    2010-12-01

    community to prioritize risk management strategies, reformulate set back requirements, improve guidelines for construction of breakwaters and other coastal infrastructure, and assess water resources impacts and protection needs.

  2. Medium-term shoreline evolution of the mediterranean coast of Andalusia (SW Spain)

    Science.gov (United States)

    Liguori, Vincenzo; Manno, Giorgio; Messina, Enrica; Anfuso, Giorgio; Suffo, Miguel

    2015-04-01

    Coastal environment is a dynamic system in which numerous natural processes are continuously actuating and interacting among them. As a result, geomorphologic, physical and biological characteristics of coastal environments are constantly changing. Such dynamic balance is nowadays seriously threatened by the strong and increasing anthropic pressure that favors erosion processes, and the associated loss of environmental, ecologic and economic aspects. Sandy beaches are the most vulnerable environments in coastal areas. The aim of this work was to reconstruct the historical evolution of the Mediterranean coastline of Andalusia, Spain. The investigated area is about 500 km in length and includes the provinces of Cadiz, Malaga, Granada and Almeria. It is essentially composed by cliffed sectors with sand and gravel pocket beaches constituting independent morphological cells of different dimensions. This study was based on the analysis of aerial photos and satellite images covering a period of 55 years, between 1956 and 2011. Aerial photos were scanned and geo-referenced in order to solve scale and distortion problems. The shoreline was considered and mapped through the identification of the wet / dry sand limit which coincides with the line of maximum run-up; this indicator - representing the shoreline at the moment of the photo - is the most easily identifiable and representative one in microtidal coastal environments. Since shoreline position is linked to beach profile characteristics and to waves, tide and wind conditions at the moment of the photo, such parameters were taken into account in the calculation of shoreline position and changes. Specifically, retreat/accretion changes were reconstructed applying the DSAS method (Digital Shoreline Analysis System) proposed by the US Geological Survey. Significant beach accretion was observed at Playa La Mamola (Granada), with +1 m/y, because the construction of five breakwaters, and at Playa El Cantal (Almeria) and close

  3. Sedimentary constraints on the development of a narrow deep strait (São Sebastião Channel, SE Brazil)

    Science.gov (United States)

    Alcántara-Carrió, Javier; Sasaki, Dalton Kei; Mahiques, Michel Michaelovitch de; Taborda, Rui; de Souza, Luiz Antonio Pereira

    2017-10-01

    The São Sebastião Channel (SSC), which separates São Sebastião Island from the continent, is a deep elongated strait on the inner shelf of the São Paulo Bight (SE Brazil). The aim of this study is to explain why it is presently sediment starved, instead of forming a tombolo. Wave data were obtained from both a WW3 model database and buoy records, and wave propagation patterns from the SWAN numerical model. Grain size trend analysis of 579 surficial sediment samples from the strait and the surrounding region served to estimate the residual transport directions. Bedload sediment transport was computed considering in situ currents and bottom sediment grain size. Moreover, six seismic profiles and one gravity core were obtained in the strait in order to evaluate the hickness of the sedimentary deposits. The geometry of the SSC (X/B=0.3, where B is the breakwater or island diameter and X is its cross-shore distance to the mainland) predicts that a tombolo should be formed, and wave patterns confirm that it is a zone sheltered from both S and NE waves. Previous studies have shown that the hydrodynamics of the SSC is controlled by wind-driven currents, which are more intense in the eastern and central sectors of the strait. The western sector is currently covered by sandy mud, whereas very coarse to fine sand prevails in the deeper eastern sector. Sediment patterns show a trend to deposition of fine sediment in the western sector of the SSC and two main depocentres located at the northern limit of the study area and at the southern mouth of the strait. Sandy mud in the western sector forms a 40-m-thick deposit close to the outer limit of Araçá Bay, whereas the remainder of the SSC is covered by a very thin layer of sandy sediments. Dominance of mud in the depositional western sector suggests low availability of sand in the area. Therefore, despite the geometry and wave patterns of the SSC favouring the formation of a tombolo, the dominance of wind-driven currents

  4. Comprehensive Prediction of Large-height Swell-like Waves in East Coast of Korea

    Science.gov (United States)

    Kwon, S. J.; Lee, C.; Ahn, S. J.; Kim, H. K.

    2014-12-01

    There have been growing interests in the large-height swell-like wave (LSW) in the east coast of Korea because such big waves have caused human victims as well as damages to facilities such as breakwaters in the coast. The LSW was found to be generated due to an atmospherically great valley in the north area of the East Sea and then propagate long distance to the east coast of Korea in prominently southwest direction (Oh et al., 2010).In this study, we will perform two methods, real-time data based and numerical-model based predictions in order to predict the LSW in the east coast of Korea. First, the real-time data based prediction method uses information which is collected by the directional wave gauge installed near Sokcho. Using the wave model SWAN (Booij et al., 1999) and the wave ray method (Munk and Arthur, 1952), we will estimate wave data in open sea from the real-time data and predict the travel time of LSW from the measurement site (near Sokcho) to several target points in the east coast of Korea. Second, the numerical-model based method uses three different numerical models; WW3 in deep water, SWAN in shallow water, and CADMAS-SURF for wave run-up (CDIT). The surface winds from the 72 hours prediction system of NCEP (National Centers for Environmental Prediction) GFS (Global Forecast System) will be inputted in finer grids after interpolating these in certain domains of WW3 and SWAN models. The significant wave heights and peak wave directions predicted by the two methods will be compared to the measured data of LSW at several target points near the coasts. Further, the prediction method will be improved using more measurement sites which will be installed in the future. ReferencesBooij, N., Ris, R.C., and Holthuijsen, L.H. (1999). A third-generation wave model for coastal regions 1. Model description and validation. J. of Geophysical Research, 103(C4), 7649-7666.Munk, W.H. and Arthur, R.S. (1952). Gravity Waves. 13. Wave Intensity along a Refracted Ray

  5. The Effectiveness, Costs and Coastal Protection Benefits of Natural and Nature-Based Defences.

    Directory of Open Access Journals (Sweden)

    Siddharth Narayan

    Full Text Available There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences-i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences and (ii analyses of the effectiveness of coastal habitats (natural defences in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become

  6. Sediment transport in the area of the Sopot pier

    Science.gov (United States)

    Przyborska, Anna; Jakacki, Jaromir; Andrzejewski, Jan

    2017-04-01

    Coastal sediment transport is a natural process that appears when energy of waves is sufficient for moving solid particles from the bottom. Sediment transport rate depends on the median diameter of local sand and it is compatible with the direction of wave propagation. Also it is natural, that any protruded from the beach construction disturbs continuity of beach transport caused by waves. The Sopot pier has been built over 100 years ago and it is the longest wooden pier on the Baltic Sea coast, it is about half kilometre long. The pier is located at the end of the Monte Casino street and it is one of the biggest attractions of the city as well as in the country. In the past and now we have observed the disturbed sediment transport in the area of the Sopot pier. But during recent years, this process has gained greater momentum. The beach at the Sopot pier has been growing by several meters. All indicates that the cause of the observed phenomenon is the marina. The marina structure which is in some distance from the shore, has been acting as a powerful, emerged breakwater boundary. As a tool the sediment transport model was implemented for Sopot pier area. The implemented numerical forecasting sediment transport model in the area of the Sopot pier reflects well the deposit growth rate for the archived data from 2010 to 2015. On the basis of differences in bathymetry data provided by the Maritime office and the analysis the model results the average deposits in accumulation in the pear area was determined to be about 16,000 m3 / year for the assumed area of analysis, the model have shown similar result. The analysis suggests that strong winds generating significant waves as well as meaningful sediment transport dominate in the autumn and winter. You cannot, however, rule out strong waves in summer. Under moderate waves the sediment transport is insignificant. The most intense movement of the sediment is observed in the vicinity of the shoreline, it disappears with

  7. Hurricane Sandy: Caught in the eye of the storm and a city's adaptation response

    Science.gov (United States)

    Orton, P. M.; Horton, R. M.; Blumberg, A. F.; Rosenzweig, C.; Solecki, W.; Bader, D.

    2015-12-01

    The NOAA RISA program has funded the seven-institution Consortium for Climate Risk in the Urban Northeast (CCRUN) for the past five years to serve stakeholder needs in assessing and managing risks from climate variability and change. When Hurricane Sandy struck, we were in an ideal position, making flood forecasts and communicating NOAA forecasts to the public with dozens of media placements, translating the poorly understood flood forecasts into human dimensions. In 2013 and 2015, by request of New York City (NYC), we worked through the NYC Panel on Climate Change to deliver updated climate risk assessment reports, to be used in the post-Sandy rebuilding and resiliency efforts. These utilized innovative methodologies for probabilistic local and regional sea level change projections, and contrasted methods of dynamic versus (the more common) static flood mapping. We participated in a federal-academic partnership that developed a Sea Level Tool for Sandy Recovery that integrates CCRUN sea level rise projections with policy-relevant FEMA flood maps, and now several updated flood maps and coastal flood mapping tools (NOAA, FEMA, and USACE) incorporate our projections. For the adaptation response, we helped develop NYC's $20 billion flood adaptation plan, and we were on a winning team under the Housing and Urban Development Rebuild By Design (RBD) competition, a few of the many opportunities that arose with negligible additional funding and which CCRUN funds supported. Our work at times disrupted standard lines of thinking, but NYC showed an openness to altering course. In one case we showed that an NYC plan of wetland restoration in Jamaica Bay would provide no reduction in flooding unless deep-dredged channels circumventing them were shallowed or narrowed. In another, the lead author's RBD team challenged the notion at one location that levees were the solution to accelerating sea level rise, developing a plan to use ecological breakwaters and layered components of

  8. Tsunami Induced Resonance in Enclosed Basins; Case Study of Haydarpasa Port In Istanbul

    Science.gov (United States)

    Kian, Rozita; Cevdet Yalciner, Ahmet; Zaytsev, Andrey; Aytore, Betul

    2015-04-01

    Coincidence of the frequency of forcing mechanisms and the natural frequency of free oscillations in the harbors or basins leads to formation of resonance oscillations and additional amplifications in the basins. This phenomenon becomes much more critical when it is caused by a tsunamis. In the cases of tsunami induced basin resonances, the wave amplifications may occur with more and unexpected damages. The harbor resilience against the marine hazards is important for the performance and success of recovery operations. Classifying the tsunami effects on the ports and harbors and on their functions is the main concern of this study. There are two types of impacts; direct impacts including structural damages due to strong currents, high water elevation and indirect ones because of basin resonance expose to seiche oscillations. The sea of Marmara has experienced numerous (more than 30) tsunamis in history where a highly populated metropolitan city Istanbul is located at North coast of Maramara sea. There are numerous ports and harbors located at Istanbul Coast. Haydarpasa port (41.0033 N, 29.0139 E) in Istanbul coast near Marmara sea, as a case study is selected to test its resilience under tsunami attack by numerical experiments. There are two breakwaters in Haydarpasa port with total length of three kilometers and the shape of basins are regular. Applying numerical model (NAMI DANCE) which solves nonlinear form of shallow water equations, the resonance oscillations in Haydarpasa Port is investigated by following the method given in Yalciner and Pelinovsky, (2006). In the applications, high resolution bathymetry and topography are used and an initial impulse is inputted to the study domain in the simulations. The computed time histories of water surface fluctuations at different locations inside the harbor are analyzed by using Fast Fourier Transform technique. The frequencies where the peaks of spectrum curves indicates the amplification of waves in the respective

  9. Mirmecofauna (Hymenoptera, Formicidae de Duas Marismas do Estuário da Lagoa dos Patos, RS: Diversidade, Flutuação de Abundância e Similaridade como Indicadores de Conservação

    Directory of Open Access Journals (Sweden)

    Cristiane Ferras Bolico

    2012-04-01

    Full Text Available O trabalho objetiva inventariar a mirmecofauna de duas marismas distintas e estimar a diversidade, similaridade, bem como relacionar a temperatura, umidade relativa do ar e a pluviosidade aos padrões de flutuação de abundância desses insetos. Além disso, foram reconhecidas as espécies que atuam como indicadores ambientais. O estudo foi realizado em duas marismas localizadas no Estuário da Laguna Lagoa dos Patos, Ilha da Torotama e Molhe Oeste da Barra. Foram capturados 853 formicídeos, distribuídos em 19 gêneros. As duas marismas apresentaram índices de diversidade e abundância semelhantes, Ds = 0,958 e I = 0,042 na Ilha da Torotama e Ds = 0,8889 e I = 0,111 no Molhe Oeste da Barra. As flutuações dos grupos de formicídeos coincidiram em ambas as áreas, ocorrendo os picos durante os meses quentes. Grupos considerados bioindicadores estiveram presentes na amostragem, fornecendo parâmetros de conservação ambiental.Myrmecofauna (Hymenoptera, Formicidae of the Two Salt Marshes Patos Lagoon Estuary, RS: Diversity, Fluctuation of the Abundance and Similarity as Indicators of ConservationAbstract. The aim of this investigation was to assess the myrmecofauna of two distinct salt marshes and to estimate the diversity, similarity, as well as to estimate the effects of temperature, relative humidity and rainfall on the fluctuation patterns of these insects. Additionally, the species that act as environmental indicators were recognized. The study was conducted in two salt marshes located in the Patos Lagoon Estuary: Torotama’s Island and West Breakwater. A total of 853 ants were sampled, distributed in 19 genera. Both marshes showed similar diversity and abundance, Ds = 0.958 and I = 0.042 in Torotama’s Island and Ds = 0.8889 and I = 0.111 in West Break Water. Trends in ant composition coincided in both areas, with a peak during the warmer months. Areas showed no similarity, due to anthropogenic factors and species’ biology. Groups

  10. Cladophora (Chlorophyta) spp. harbor human bacterial pathogens in nearshore water of Lake Michigan

    Science.gov (United States)

    Ishii, S.; Yan, T.; Shively, D.A.; Byappanahalli, M.N.; Whitman, R.L.; Sadowsky, M.J.

    2006-01-01

    Cladophora glomerata, a macrophytic green alga, is commonly found in the Great Lakes, and significant accumulations occur along shorelines during the summer months. Recently, Cladophora has been shown to harbor high densities of the fecal indicator bacteria Escherichia coli and enterococci. Cladophora may also harbor human pathogens; however, until now, no studies to address this question have been performed. In the present study, we determined whether attachedCladophora, obtained from the Lake Michigan and Burns Ditch (Little Calumet River, Indiana) sides of a breakwater during the summers of 2004 and 2005, harbored the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC),Salmonella, Shigella, and Campylobacter. The presence of potential pathogens and numbers of organisms were determined by using cultural methods and by using conventional PCR, most-probable-number PCR (MPN-PCR), and quantitative PCR (QPCR) performed with genus- and toxin-specific primers and probes. WhileShigella and STEC were detected in 100% and 25%, respectively, of the algal samples obtained near Burns Ditch in 2004, the same pathogens were not detected in samples collected in 2005. MPN-PCR and QPCR allowed enumeration of Salmonella in 40 to 80% of the ditch- and lakeside samples, respectively, and the densities were up to 1.6 × 103 cells per g Cladophora. Similarly, these PCR methods allowed enumeration of up to 5.4 × 102 Campylobacter cells/gCladophora in 60 to 100% of lake- and ditchside samples. The Campylobacterdensities were significantly higher (P < 0.05) in the lakeside Cladophora samples than in the ditchside Cladophora samples. DNA fingerprint analyses indicated that genotypically identical Salmonella isolates were associated with geographically and temporally distinct Cladophora samples. However, Campylobacter isolates were genetically diverse. Since animal hosts are thought to be the primary habitat for

  11. Coastal flooding hazard assessment on potentially vulnerable coastal sectors at Varna regional coast

    Science.gov (United States)

    Eftimova, Petya; Valchev, Nikolay; Andreeva, Nataliya

    2017-04-01

    Storm induced flooding is one of the most significant threats that the coastal communities face. In the light of the climate change it is expected to gain even more importance. Therefore, the adequate assessment of this hazard could increase the capability of mitigation of environmental, social, and economic impacts. The study was accomplished in the frames of the Coastal Risk Assessment Framework (CRAF) developed within the FP7 RISC-KIT Project (Resilience-Increasing Strategies for Coasts - toolkit). The hazard assessment was applied on three potentially vulnerable coastal sectors located at the regional coast of Varna, Bulgarian Black Sea coast. The potential "hotspot" candidates were selected during the initial phase of CRAF which evaluated the coastal risks at regional level. The area of interest comprises different coastal types - from natural beaches and rocky cliffs to man modified environments presented by coastal and port defense structures such as the Varna Port breakwater, groynes, jetties and beaches formed by the presence of coastal structures. The assessment of coastal flooding was done using combination of models -XBeach model and LISFLOOD inundation model applied consecutively. The XBeach model was employed to calculate the hazard intensities at the coast up to the berm crest, while LISFLOOD model was used to calculate the intensity and extent of flooding in the hinterland. At the first stage, 75 extreme storm events were simulated using XBeach model run in "non-hydrostatic" mode to obtain series of flood depth, depth-velocity and overtopping discharges at the predefined coastal cross-shore transects. Extreme value analysis was applied to the calculated hazard parameters series in order to determine their probability distribution functions. This is so called response approach, which is focused on the onshore impact rather than on the deep water boundary conditions. It allows calculation of the hazard extremes probability distribution induced by a

  12. PEMETAAN PASANG SURUT DAN ARUS LAUT PULAU BATAM DAN PENGARUHNYA TERHADAP JALUR TRANSPORTASI ANTARPULAU

    Directory of Open Access Journals (Sweden)

    Sudra Irawan

    2016-03-01

    Full Text Available TIDAL AND CURRENT MAPPING OF BATAM ISLAND AND THEIR EFFECT ON THE INTER-ISLAND TRANSPORTATIONThe strategic geographical position of Batam Island makes sea transportation become a basic means connecting the islands of the Riau Islands, Riau, Kalimantan, even with neighboring Singapore and Malaysia. The development of coastal areas and the determination of the transportation ways needs tidal and ocean currents data. This study measures and analyzes the tidal type usingmeasuring signs and current patterns using Lagrangian method, then presented in the web form. Five research sites were selected by purposive sampling method with a measurement time of 24 hours in one hour intervals. The results showed that the type of tidal in Batam Island in general is semidiurnal tide. Tidal period an average of 12 hours and 24 minutes. Wave height of about 0.2 to 2.77 meters from the south to the northwest. Batam Island ocean current patterns ranging from 0.02 m/s to 0.1 m/s from north towards the northeast. Tidal and current survey is one of the conditions in developing inter-island transportation. The tidal and current is useful in design port building, determining the route of transport, port basin design and planning of the breakwater.Keywords: current patterns, lagrangian, signs measure, tidal, transport route.ABSTRAKPosisi geografis Pulau Batam yang strategis membuat jalur transportasi laut merupakan sarana dasar menghubungkan antarpulau di Kepulauan Riau, Riau, Kalimantan, bahkan dengan negara tetangga Singapura dan Malaysia. Pengembangan wilayah pesisir dan penentuan jalur transportasi membutuhkan data pasang surut dan arus laut. Penelitian ini mengukur dan menganalisis tipe pasang surut dengan rambu ukur dan pola arus dengan metode metode Lagrangian, kemudian disajikan dalam bentuk web. Dipilih lima lokasi penelitian berdasarkan metode Purposive Sampling dengan waktu pengukuran 24 jam dalam interval satu jam. Hasil penelitian menunjukkan bahwa tipe pasang

  13. Ultra-High Resolution Four Dimension Imaging Across the Earth Sciences (Invited)

    Science.gov (United States)

    Bawden, G. W.

    2010-12-01

    Geodesy in the 21st century is embracing two distinct areas of research: “Geodetic Science” — the scientific discipline that deals with the measurement and representation of the kinematics and dynamics of the Earth’s size, shape, orientation, and gravity field; and “Geodetic Applications”— the wide range of applied geodetic techniques contributing to research not only within the geodetic community, but also across the broad natural science spectrum including, hazards, hydrology, ecosystems, geomorphology, and climate change. Ground-based LiDAR, known as Tripod/Terrestrial LiDAR (T-LiDAR) and Terrestrial Laser Scanning, is a rapidly evolving emergent ‘geodetic science’ technology that is also a forefront ‘geodetic application’ tool that will allow researchers from multiple disciplines to address questions that were unanswerable only 5 years ago. T-LiDAR has unsurpassed ability to collect ultra-high resolution detailed (cm to sub-centimeter) 3D and 4D point cloud measurements that are on scales ranging from individual tree branches and small outcrops to landscapes and glaciers upwards of a few square kilometers in extent. T-LiDAR is ushering in a new era of geodetically driven mesoscopic scale science with true 3D site characterization and 4D change detection. T-LiDAR has made it possible to image 4D postseismic surface change through tracking how elements on the land surface move over time; fence post, bridges, buildings, trees, and the unique land surface morphology elements are now becoming tractable benchmark-like objects whose 3D positions change. Similar approaches have been applied to a wide range of applications including landslides, rock falls, glacial motion, fissure growth, breakwater/structural stability, and mine collapses. T-LiDAR can image how basins respond to aeolian and fluvial processes following major fires through detailed 4D time-series that show how sediment and material move through a denuded landscape via dry ravel

  14. Assessment of tsunami resilience of Haydarpaşa Port in the Sea of Marmara by high-resolution numerical modeling

    Science.gov (United States)

    Aytore, Betul; Yalciner, Ahmet Cevdet; Zaytsev, Andrey; Cankaya, Zeynep Ceren; Suzen, Mehmet Lütfi

    2016-08-01

    domains in 3-m and 1-m resolutions and the water elevations computed from the previous simulations were inputted from the border of the large domain. A tsunami numerical code, NAMI DANCE, was used in the simulations. The tsunami parameters in the highest resolution were computed in and around the port. The effect of the data resolution on the computed results has been presented. The performance of the port structures and possible effects of tsunami on port operations have been discussed. Since the harbor protection structures have not been designed to withstand tsunamis, the breakwaters' stability becomes one of the major concerns for less agitation and inundation under tsunami in Haydarpaşa Port for resilience. The flow depth, momentum fluxes, and current pattern are the other concerns that cause unexpected circulations and uncontrolled movements of objects on land and vessels in the sea.

  15. X-Band wave radar system for monitoring and risk management of the coastal infrastructures

    Science.gov (United States)

    Ludeno, Giovanni; Soldovieri, Francesco; Serafino, Francesco

    2017-04-01

    The presence of the infrastructures in coastal region entails an increase of the sea level and the shift of the sediment on the bottom with a continuous change of the coastline. In order to preserve the coastline, it has been necessary to resort the use of applications coastal engineering, as the construction of the breakwaters for preventing the coastal erosion. In this frame, the knowledge of the sea state parameters, as wavelength, period and significant wave height and of surface current and bathymetry can be used for the harbor operations and to prevent environmental disasters. In the last years, the study of the coastal phenomena and monitoring of the sea waves impact on the coastal infrastructures through the analysis of images acquired by marine X-band radars is of great interest [1-3]. The possibility to observe the sea surface from radar images is due to the fact that the X-band electromagnetic waves interact with the sea capillary waves (Bragg resonance), which ride on the gravity waves. However, the image acquired by a X-band radar is not the direct representation of the sea state, but it represents the sea surface as seen by the radar. Accordingly, to estimate the sea state parameters as, direction, wavelength, period of dominant waves, the significant wave height as well as the bathymetry and surface current, through a time stack of radar data are required advanced data processing procedures. In particular, in the coastal areas due to the non-uniformity of sea surface current and bathymetry fields is necessary a local analysis of the sea state parameters. In order to analyze the data acquired in coastal area an inversion procedure defined "Local Method" is adopted, which is based on the spatial partitioning of the investigated area in partially overlapping sub-areas. In addition, the analysis of the sea spectrum of each sub-area allows us to retrieve the local sea state parameters. In particular, this local analysis allows us to detect the reflected

  16. Hazard Assessment and Early Warning of Tsunamis: Lessons from the 2011 Tohoku earthquake

    Science.gov (United States)

    Satake, K.

    2012-12-01

    . Tsunami hazard assessments or long-term forecast of earthquakes have not considered such a triggering or simultaneous occurrence of different types of earthquakes. The large tsunami at the Fukushima nuclear power station was due to the combination of the deep and shallow slip. Disaster prevention for low-frequency but large-scale hazard must be considered. The Japanese government established a general policy to for two levels: L1 and L2. The L2 tsunamis are the largest possible tsunamis with low frequency of occurrence, but cause devastating disaster once they occur. For such events, saving people's lives is the first priority and soft measures such as tsunami hazard maps, evacuation facilities or disaster education will be prepared. The L1 tsunamis are expected to occur more frequently, typically once in a few decades, for which hard countermeasures such as breakwater must be prepared to protect lives and properties of residents as well as economic and industrial activities.

  17. Headland-bay beach planform stability of Santa Catarina State and of the Northern Coast of São Paulo State

    Directory of Open Access Journals (Sweden)

    Lucas F. Silveira

    2010-06-01

    Full Text Available This paper presents the results of the planform stability classification for the headland-bay beaches of the State of Santa Catarina and of the Northern Coast of São Paulo, based on the application of the Parabolic Bay-Shape Equation (PBSE to aerial images of the beaches, using the software MEPBAY®. For this purpose, georeferenced mosaics of the QuickBird2® satellite imagery (for the State of Santa Catarina and vertical aerial photographs (for the northern coast of São Paulo State were used. Headland-bay beach planform stability can be classified as: (1 in static equilibrium, (2 in dynamic equilibrium, (3 unstable or (4 in a state of natural beach reshaping. Static equilibrium beaches are the most frequent along the coast of the State of Santa Catarina and the Northern Shore of São Paulo, notably along the most rugged sectors of the coast and those with experiencing lower fluvial discharge. By comparison, dynamic equilibrium beaches occur primarily on the less rugged sectors of the coast and along regions with higher fluvial discharge. Beaches in a state of natural beach reshaping have only been found in SC, associated with stabilized estuarine inlets or port breakwaters. However, it is not possible to classify any of these beaches as unstable because only one set of images was used. No clear relation was observed between a beach's planform stability and other classification factors, such as morphodynamics or orientation.Este trabalho apresenta resultados da classificação da estabilidade da forma em planta das praias de enseada do Estado de Santa Catarina e do Litoral Norte de São Paulo, realizada através da aplicação do modelo parabólico a imagens aéreas utilizando o software MEPBAY®. Para isso foram construídos mosaicos georeferenciados com imagens do satélite QuickBird2® (para o Estado de Santa Catarina e com fotografias aéreas verticais (para o Litoral Norte de São Paulo. Quanto à estabilidade de sua forma em planta, as

  18. Characterization of Mineral Assemblages in Ancient Roman Maritime Concrete with Synchrotron X-ray Techniques

    Science.gov (United States)

    Meral, C.; Jackson, M. D.; Monteiro, P. J.; Wenk, H.

    2012-12-01

    Romans used lime and aluminosilicate-rich volcanic ash to bind tuff aggregates in concrete structures that have remained durable for 2000 years. A major accomplishment of Roman engineers was to construct enduring coastal underwater structures in seawater, which were important to long-distance trade and military endeavors. Two millennia later, the reasons for the extraordinary durability of the maritime structures remain enigmatic. The concretes are highly complex composites composed of relict lime, tuff and pumice clasts and pozzolanic reaction products. Calcium-chloroaluminates and sulfoaluminates occur in certain relict voids. Further understanding of their mineralogical components would provide guidelines in designing future structures. Here, we use synchroton radiation applications to characterize certain phases within a Roman maritime mortar specimen from a breakwater in Pozzuoli Bay, Baianus Sinus, near Naples. We performed X-ray computed micro-tomography (μ-XCT) at beamline 8.3.2 of the Advanced Light Source (ALS) at Lawrence Berkeley Laboratories to segment the complex composite without damaging the specimen. We isolated certain relict sub-spherical voids and illustrated crystal morphologies with 3-D reconstructions. We then used beamline 12.3.2 at the ALS to provide highly accurate identifications of diverse crystal phases in various mortar components - relict lime clasts, tuff or pumice clasts, cementitious matrix and relict voids - in sites previously identified and characterized with petrogaphic techniques. X-ray micro-fluorescence (μ-XRF) mapping provided calcium and iron maps of the sites, which were useful in selecting fine-scale areas for scanning transmission X-ray micro-diffraction (μ-XRD) mapping at high spatial resolution, about 1 micron. The μ-XRD analyses utilized both monochromatic and polychromatic light measurements. Polychromatic light was more appropriate for phases with grain sizes larger than the doubly focused X-ray beam, about 1 x

  19. Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study

    Science.gov (United States)

    Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

    2010-05-01

    The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present

  20. A Powerful Method of Measuring Sea Wave Spectra and their Direction

    Science.gov (United States)

    Blasi, Christoph; Mai, Stephan; Wilhelmi, Jens; Zenz, Theodor; Barjenbruch, Ulrich

    2014-05-01

    Besides the need of precise measurements of water levels of the sea, there is an increasing demand for assessing waves in height and direction for different purposes like sea-wave modelling and coastal engineering. The design of coastal structures such as piles, breakwaters, and offshore structures like wind farms must take account of the direction of the impacting waves. To date, records of wave directions are scarce. The reason for this might be the high costs of purchasing and operating such measuring devices. These are usually buoys, which require regular maintenance. Against this background, the German Federal Institute of Hydrology (BfG) developed a low-cost directional sea-wave monitoring system that is based on commercially available liquid-level radar sensors. These sensors have the advantage that they have no contact to the fluid, i.e. the corrosive sea water. The newly developed device was tested on two sites. One is the tide gauge 'Borkum Südstrand' that is located in the southern North Sea off the island of Borkum. The other one is the 'Research Platform FINO1' approximately 45 km north of the island of Borkum. The main focus of these tests is the comparison of the data measured by the radar-based system with those of a conventional Directional Wave Rider Buoy. The general conditions at the testing sites are good for the tests. At the tide gauge 'Borkum Südstrand' waves propagate in different directions, strongly influenced by the morphological conditions like shallow waters of the Wadden Seas and the coast of the island of Borkum. Whereas on the open sea, at the site FINO1, the full physical conditions of the sea state, like heavy storms etc. play an important role. To determine and measure the direction of waves, the device has to be able to assess the wave movements in two dimensions. Therefore, an array of several radar sensors is required. Radar sensors are widely used and well established in measuring water levels, e.g. in tanks and basins

  1. Avaliação da qualidade microbiológica da água do açude Engenheiro Ávidos, Cajazeiras-PB

    Directory of Open Access Journals (Sweden)

    A. E. F. Marques

    2015-12-01

    causing different types of pollution, causing a great waste and water contamination. In this context, it is essential to know the quality of water that is consumed in a city. Therefore, this study aimed to carry out an assessment of the bacteriological water quality of the weir Engenheiro Avidos that supplies the city of Cajazeiras - PB. The work was performed by the quantitative study applied exploratory, in which they analyzed the presence of heterotrophic bacteria from fecal contamination, in other words, untreated sewage. Three samples were collected at different points of the weir, these being: intake weir, proximity to housing and seawall. After analysis it was identified that the weir Engenheiro Avidos is within the parameters required by CONAMA, since were identified 150 (intake weir, 30 (housing and 0 (the breakwater coliforms per 100 ml of water, while also being among the values allowed by CONAMA, identifying yet, an elevation the amount of micro-organisms in the intake weir, which can be explained by the proximity to the town of São José de Piranhas and possible sewage. In this context is emphasized the importance of water quality monitoring that are designed primarily for human consumption, acting preventively about contamination to man.

  2. Ampliación del puerto Lyttelton. Nueva Zelanda

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    Editorial, Equipo

    1965-05-01

    Full Text Available Lyttleton Port Authority has drawn up a project for the reform and construction of new wharves and breakwaters, to cater for the increasing sea traffic. The cost of the project is 4.5 million pounds. The main work consists of a 1,070 m long front wharf, built in deep water, and apt for use by large ships. The structure of the wharf consists of a filled in zone, taken from the sea, along the edge of which a row of piles has been arranged, to support the wharf itself. This has been made with hard Australian timber. But the platform over the filled in zone is built with soft local timber. The hills rising along the coastline have been traversed by two tunnels: one for the roadway and the other to take the railway. These communication lines, which save 11 km, will link the harbour with Christchurch, the most important city in South Island. The bottom, where the wharf has been made, was soft mud, awkward to contain and control. To overcome this difficulty a simple and ingenious method was adopted. Loads of stone, from nearby quarry residues, were thrown into the mud. The stones pushed out the mud in the manner of a wavefront. The mud was then dredged away, and the stone filling operation was continued. Stone had to be used as there was insufficient sand in the neighbourhood.La Junta de Obras del puerto de Lyttelton (Nueva Zelanda ha redactado un proyecto de reforma y construcción de nuevos muelles y rompeolas para absorber el creciente movimiento portuario, cuyo coste se eleva a 4,5 millones de libras. La obra consiste en un muelle frontal, continuo, de 1.070 m de longitud, en zona de gran calado, capaz para que atraquen barcos de gran tonelaje. La estructura está constituida por una zona de rellenos, ganados al mar, en cuyo frente se hallan unas filas de pilotes sobre los que descansa la estructura del muelle, construida a base de madera dura australiana; en cambio, la plataforma formada sobre el relleno es de madera blanda del país. Los montes

  3. 50 Years of coastal erosion analysis: A new methodological approach.

    Science.gov (United States)

    Prieto Campos, Antonio; Diaz Cuevas, Pilar; Ojeda zujar, Jose; Guisado-Pintado, Emilia

    2017-04-01

    that transect). While the proxy, the most recommended in the research literature, defined as the upper limit of the beach active profile (backshore/foredune, cliff or infrastructure limit if exists) guarantees the exclusion of uncertainties linked to either, tides regime (very important in the Atlantic sector) and any seasonal variations of the beach profile. Spatially, results show a predominance of sectors under erosion (52% -312km - for global period 1956-2011 and 42% -249 km- for most recent period of time 1977-2011), corresponding to mean retreats of 28 m and 20 m for each period respectively. Paradoxically, when incorporating the accumulative rates (positive and negative) for each period, accretional areas appear to be greater than erosional ones, as the methodology simplifies calculations and thus consider coastal erosion as two-dimensional (distances between proxies) whereas it is a three-dimensional process. Greater erosion occurs along the Mediterranean coast as well as progressive reduction of eroded and accreted sectors on behalf of an induced increment of stable sectors driven by the presence of coastal infrastructures (promenades, seawalls, and breakwater) which prevent the shoreline from migrating inland. The usability of the methodology and its integration on a web-based viewer undoubtedly offers a new opportunity of data exploitation, as combines natural and anthropogenic factors involved in coastal erosion/accretion in a simple but effective way.

  4. California State Waters Map Series--Hueneme Canyon and vicinity, California

    Science.gov (United States)

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Clahan, Kevin B.; Sliter, Ray W.; Wong, Florence L.; Yoklavich, Mary M.; Normark, William R.

    2012-01-01

    of three smaller, unnamed headless canyons incised into the shelf southeast of Hueneme Canyon. The shelf is underlain by tens of meters of interbedded upper Quaternary shelf, estuarine, and fluvial deposits that formed as sea level fluctuated in the last several hundred thousand years. Hueneme Canyon extends about 15 km offshore from its canyon head near the dredged navigation channel of the Port of Hueneme. The canyon is relatively deep (about 150 m at the California's State Waters limit) and steep (canyon flanks as steep as 25° to 30°). Historically, Hueneme Canyon functioned as the eastern termination of the Santa Barbara littoral cell by trapping all eastward littoral drift, not only feeding the large Hueneme submarine fan but acting as the major conduit of sediment to the deep Santa Monica Basin; however, recent dredging programs needed to maintain Channel Islands Harbor and the Port of Hueneme have moved the nearshore sediment trapped by jetties and breakwaters to an area southeast of the Hueneme Canyon head. Seafloor habitats in the broad Santa Barbara Channel region consist of significant amounts of soft sediment and isolated areas of rocky habitat that support kelp-forest communities nearshore and rocky-reef communities in deep water. The potential marine benthic habitat types mapped in the Hueneme Canyon and vicinity map area are related directly to the geomorphology and sedimentary processes that are the result of its Quaternary geologic history. The two basic megahabitats in the map area are Shelf (continental shelf) and Flank (continental slope). The flat seafloor of the continental shelf in the Hueneme Canyon and vicinity map area is dynamic, as indicated by mobile sand sheets and coarser grained scour depressions. The active Hueneme Canyon provides considerable relief to the continental shelf in the map area, and its irregular morphology of eroded walls, landslide scarps, and deposits and gullies provide promising habitat for groundfish, crabs

  5. California State Waters Map Series: offshore of Santa Barbara, California

    Science.gov (United States)

    Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Greene, H. Gary; Krigsman, Lisa M.; Kvitek, Rikk G.; Dieter, Bryan E.; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Conrad, James E.; Cochran, Susan A.; Johnson, Samuel Y.; Cochran, Susan A.

    2013-01-01

    utilized Santa Barbara coastal zone, including Arroyo Burro Beach Park, Leadbetter Beach, East Beach, and “Butterfly Beach.” There are ongoing coastal erosion problems associated with both development and natural processes; between 1933–1934 and 1998, cliff erosion in the map area occurred at rates of about 0.1 to 1 m/yr, the largest amount (63 m) occurring at Arroyo Burro in the western part of the map area. In addition, development of the Santa Barbara Harbor, which began in 1928, lead to shoaling west of the harbor as the initial breakwater trapped sand, as well as to coastal erosion east of the harbor. Since 1959, annual harbor dredging has mitigated at least some of the downcoast erosion problems. The Offshore of Santa Barbara map area lies in the central part of the Santa Barbara littoral cell, which is characterized by littoral drift to the east-southeast. Drift rates have been estimated to be about 400,000 tons/yr at Santa Barbara Harbor. Sediment supply to the western and central parts of the littoral cell, including the map area, is largely from relatively small transverse coastal watersheds. Within the map area, these coastal watersheds include (from east to west) San Ysidro Creek, Oak Creek, Montecito Creek, Sycamore Creek, Mission Creek, Arroyo Burro, and Atascadero Creek. The Ventura and Santa Clara Rivers, the mouths of which are about 40 to 50 km southeast of Santa Barbara, are much larger sediment sources. Still farther east, eastward-moving sediment in the littoral cell is trapped by Hueneme and Mugu Canyons and then transported to the deep-water Santa Monica Basin. The offshore part of the map area consists of a relatively flat and shallow continental shelf, which dips gently seaward (about 0.4° to 0.8°) so that water depths at the 3-nautical-mile limit of California’s State Waters are about 45 m in the east and about 75 m in the west. This part of the Santa Barbara Channel is relatively well protected from large Pacific swells from the north