Coastal Engineering

Coastal erosion poses a significant challenge along Africa's Atlantic coast, with flooding ranking as the second most pressing threat after erosion. This issue is particularly acute in Cameroon, especially along the Kribian coast and the Wouri estuary, where Cape Cameroon is undergoing severe erosional processes. The central research question of this study examines whether the erosion in the Wouri estuary is due to local factors or part of a broader dynamic affecting the entire Atlantic African shoreline. The study aims to achieve three main objectives: (i) to map shoreline dynamics in the Wouri estuary from 1975 to 2019, identifying and quantifying eroding segments; (ii) to analyze factors contributing to erosion in the Wouri estuary and those common to other Atlantic African coasts; and (iii) to contextualize these findings within current scientific literature. Utilizing Hilhorst's theory of "reciprocity" or "complexity", the study recognizes that coastal areas are shaped by both physical and human factors influencing natural hazards like erosion and flooding. To investigate the causes of coastal erosion, a smaller-scale map (1:5000) derived from Landsat images (30-m resolution) and a larger-scale map (1:1500) based on Pleiades and Google Earth images (0.5-m resolution) were employed, focusing on Cape Cameroon. The imagery covers various years:

This study deals with the sea-flood risk in a small lagoon called “Etang de La Palme” on the mediterranean coast of Languedoc (south of France). The risk of a sea-flood in this vulnerable area had been analysed through an integrated approach, combining the ...

Thermaikos Gulf, located in the northeastern Mediterranean Sea, faces significant anthropogenic pressures and natural hazards, requiring reliable metocean forecasts for weather, ocean circulation, sea levels, waves, and hazard predictions, including pollutant transport, coastal floods, and freshwater discharges. The Wave4Us operational platform addresses these needs by providing high-resolution and specialised forecasts, accessible to local authorities, researchers, and the public. Additionally, on-demand predictions for marine pollution, coastal inundation, and heatwaves offer real-time insights to emergency responders and coastal authorities during hazardous events. This study presents the platform's structure, modelling advancements, and predictive skill for specific hazards. Forecast efficiency is evaluated against satellite and field observations: (i) the simulated oil spill spreading is verified by satellite data; (ii) the modelled freshwater discharges are validated against field measurements (high correlation, RMSE < 10%); (iii) a pronounced river plume spreading is confirmed by ocean/tracer simulations and satellite imagery; (iv) the prediction of sea level, wave conditions, and coastal flooding under a severe low-pressure system is validated against measurements and documented events; (v) the marine heatwave predictions is confirmed by comparing simulated and satellite sea temperatures (error < 1%). These evaluations demonstrate the platform's reliability in forecasting key environmental risks, aiding decision-making and response efforts in the Thermaikos Gulf region.

The cost of reshaping a horizontally composite caisson breakwater (covered with wave-dissipating blocks) is estimated taking into account the effect of the sea level rise due to the global warming. The effect of the sea level rise on the water level at the toe of the breakwater is also discussed. When accounting for the sea level rise, the total expected repair cost increases due to increasing severity of the incident wave conditions at the toe of the breakwater.

Displacement of armor blocks on submerged breakwaters is computed with Discrete Element Method (DEM). The shape of the armor block is modeled as the coupling of nine spheres. The wave force acting on the armor blocks are estimated by Morison-type Formula using the water particle velocity calculated by CADMAS-SURF. The simulated results are qualitatively compared with experimental results. The numerical model approximately predicts the position where the armor blocks peels off.

Motions of pebbles on an artificial pebble beach were measured by tracking tracers. After the beach profile reached equilibrium, pebbles moved mainly in the longshore direction parallel to the shore line under the condition of oblique wave incidence. Intensive motions of pebbles were observed in the swash zone and the maximum displacement reached 30m during one week. The authors proposed a numerical procedure for analyzing pebble motion. The motion of pebble up to the maximum wave set-up point can be predicted numerically when the time and spatial variation of water particle velocity and fluid force on pebbles are given.

The repair cost over the lifetime for caisson breakwaters covered with wave-dissipating blocks is estimated. The repair cost is estimated as the sum of the cost for repairing the wave-dissipating works and the cost equivalent to the amount of damage to the harbor area. In this study, it is assumed that the subsidence of the crest height of the wavedissipating works due to wave attacks causes the increase in the transmitted wave height behind the breakwater. The variations of the repair costs under several conditions are discussed.

Motions of pebbles on an artificial pebble beach were measured by tracking tracers. After the beach profile reached equilibrium, pebbles moved mainly in the longshore direction parallel to the shore line under the condition of oblique wave incidence. Intensive motions of pebbles were observed in the swash zone and the maximum displacement reached 30m during one week. The authors proposed a numerical procedure for analyzing pebble motion. The motion of pebble up to the maximum wave set-up point can be predicted numerically when the time and spatial variation of water particle velocity and fluid force on pebbles are given.

This study explores new ways to estimate the exposure of properties (at the plot holding level) to coastal flooding based on highly detailed inundation hazard maps (Makris et al., 2024). These are produced by a recent version of the CoastFLOOD model (Makris et al., 2023), specifically designed for high-resolution (1-2 m grid-scale) simulations of coastal inundation driven by extreme SLE scenarios along South Florida’s shorelines over a 30-year timeframe (1994-2023). The primary aim is to analyze the interannual variability of urban flooding impacts on key residential areas in Miami while evaluating the building-level exposure to seawater floods along the Biscayne Bay coast and Miami Beach. The study also investigates long-term SLE trends and extremes using historical tide gauge records to minimize the uncertainty of environmental parametric inputs. The goal is to improve understanding of seawater inundation impacts and support coastal flood risk assessment at the building and property levels using detailed GIS flood maps.

Lack in function in the well-known MIKE 21 Sediment Plume modelling for simulation of dredging scenarios had brought to a level of discrepancies between the model results and MODIS TSS measurement. This paper aims to determine the suspension of passive plume from dredging using MODIS images, in relation to the bed shear stress (BSS). MODIS images with 250m resolutions were used as standard for TSS measurement while BSS was derived from a calibrated model of the study area. Correlation study was conducted between MODIS and In-situ TSS and it shows an acceptable correlation of ? 2 = 0.5258 and ? 2 = 0.2256 at Seagrass and Paroo stations. Lower correlation between sediment suspension and modelled bed shear stress was achieved at ? 2 = 0.2519, for BSS ranging from 0 to 0.3N/m 2 for BHD loading operation. However, strong correlation was observed for smaller bed shear stress range (from 0 N/m 2 up to 0.08 N/m 2 ) for TSHD loading operation with ? 2 = 0.9194. It was found that the concerns due to the lower correlation coefficients achieved are because of factors such as MODIS resolution and the limitations to separate the long-term and short term sources.

Water and Environment down stream Escherichia coli gigabyte geographical information system global positioning system Hydro Electric Corporation [was Hydro Electric Commission] King Point [in Macquarie Harbour] left hand side megabyte megahertz mean diurnal spring tide range Mt. Lyell Remediation, Research and Demonstration Program mean semi-diurnal spring tide range NUMERICAL MODELLING OF MACQUARIE HARBOUR

The effect of ceiling height on the symbolic distance effect Masashi Sugimoto Kyoto University Takashi Kusumi Kyoto University Tokika Kurita Nagoya University Atsuo Ishikawa Takenaka Corporation Takeshi Sakaguchi Takenaka Corporation Megumi Nabetani Takenaka Corporation Hiroki Takahashi Takenaka Corporation Megumi Nishida Takenaka Corporation Abstract: The present study investigated the effect of ceiling height on the symbolic distance effect (SDE). We hypothesized that a high/low ceiling height would produce a small/large SDE through divergent/convergent thinking. We prepared three SDE tasks: numerical, spatial, and temporal. Participants conducted these tasks in both high and low ceiling conditions. Results showed that in the spatial and temporal tasks, a high ceiling height produced smaller SDEs, and a low ceiling produced larger SDEs (but not in the numerical task). These results suggest that the environment affects not only cognitive performance but also the nature of mental re...

-Tests have been carried out to investigate the influence of toe berm on the recession of berm breakwaters. -Model tests showed that toe berm width and thickness both have considerable influence on recession reduction. -A design formula has been developed to account for the effects of toe configuration on berm recession. -Results of the present research can be used as a guideline for the conceptual design of berm breakwaters including a wide toe berm.

Berm breakwaters are rubble mound structures in which the seaward slope of the initial profile may be reshaped to become more stable under severe wave attack. The stones in the seaward slope move from the initial slope to an equilibrium profile. A 2D experimental study has been carried out in a wave flume at a hydraulic laboratory of Tarbiat Modares University to study the effects of sea state and structural parameters on the reshaped profile parameters of such breakwaters. A series of 287 tests have been performed to cover the effect of various sea state conditions such as wave height, wave period, number of waves and water depth at the toe of the structure, and structural parameters such as berm width, berm elevation above still water level and armor stone size. All the tests have been done employing irregular waves with a JONSWAP spectrum. In this paper, first the reshaped profiles are schematized, and then the key parameters of the reshaped seaward profiles such as step height, step length and depth of intersection point of initial and reshaped profile are investigated, using results of this experimental work. Eventually, formulae that include some sea state and structural parameters are derived for estimation of the reshaped profile parameters. To assess the validity of the proposed formulae, comparisons are made between the estimated parameters of reshaped profiles by these formulae and earlier formulae given by other researchers. The comparisons show that the estimation procedure foretells reshaping parameters well and with less scatter according to the present data and also other experimental results within the range of parameters tested.

Force identification, as a specific type of inverse problem, involves reconstructing the force distribution on a structure from measured data. Having an accurate knowledge of the exact loading on a structure or mechanical system is important in any situation where the loading forms a crucial component in the design of the structure, i.e. when the unknown load can be regarded as critical and dictates the design, but measuring these loads is not always possible resulting in the necessity to obtain them by means of such reconstruction. Since the wind load may constitute a critical loading for high towers or mass structures and since, furthermore, it is in general difficult to measure a time-varying force on a structure, especially if the force acts as a continuous loading, the identification of time-varying wind loads on a structure presents itself as an interesting and challenging force identification application. Obtaining these forces requires an indirect computation using measured response data in conjunction with a mathematical model of the structure.

Coastal environments are highly dynamic and sensitive to interference and variations caused by the numerous natural and anthropogenic agents. The northern coast of Northeastern Brazil has undergone intense erosion in recent years. However, the construction of the Pecém Port modified the beach and shoreline features differently from the adjacent areas. This article describes using remote-sensing images integrated with a Geographic Information System to evaluate the sedimentary balance and morphological changes observed in the sandy beach area that was affected by the construction of Pecém Port. Two methods were applied to the RapidEye images to quantify the short-time changes that occurred on the coast. The Digital Shoreline Analysis System method showed that the beach width increased west to the port, which was calculated by the Change Polygon Approach determined by intersecting and uniting polygons to estimate the difference between the areas over time. The short-time analysis results showed changing coastal morphology, demonstrating that the anthropic interventions in the region are transforming significantly the natural elements that make up the region landscape. Between 2011 and 2014, the investigated beach stretch of approximately 3 km suffered an accretion process of more than 102,000 m 2 over 3 years. The high spatial resolution of satellite images, digital processing imaging techniques and geostatistical methods were effective in this study, allowing understanding the recent changes in the area.

The two•dimensional steady flow of acoastal flow past a headland has been considered. Results froro a numerical model are presented to show the transient and steady state flow structures downstream of the headland, for a range of external parameter8. It is demonstrated that the flows are of two types, The first type, which is characterised by low values of the bottom friction parameter (M) and low values of the Froude number (Fr), shows deflection of the incident flow around the cape tip and attachment of the flow to the rear face of the headland. For higher values of M and Fr, separation of the flow occurs at t.he tip of the headland end an attached eddy is generated downstream. Eddy shedding is not observed. The results show that the size of the attached eddy and the vorticity distribution within it are controlled strongly b~the value of M, though the maximum vorticity within the eddy depends only upon the incident flow velOCity U and the horiwntal dimension L of the obstruction. Evidence of oscillatory behaviour is detected during the transient adjustment phase of flow development. with the period of the oscillations being of the same order as vortex shedding periods for the same geometry.

This research investigates the morphological response of coastlines to the construction of groins, focusing on both single groins and paired groins. The evolution of the coastline is analyzed with the aim of identifying a new stable coastline geometry. The approach involves modeling the stable coastline using polynomial functions, where the polynomial coefficients are determined through the application of point-specific and linespecific characteristics, as well as the principle of mass conservation. The resulting stable coastline configuration typically forms a crenulate-shaped bay an equilibrium shoreline geometry occurring between two headlands. The derived geometry, whether partial or complete, exhibits features consistent with the known characteristics and dimensions of a crenulate-shaped bay.The modeled stable coastline can be calibrated against empirical crenulate bay profiles, confirming its validity as a representation of an actual stable coastal form.

Complex fjord topography (bathymetry and coastline) may differentiate significantly wave conditions not only compared with the offshore ones but in the vicinity of few tens of meters. In the present work, possible inhomogeneities of wave conditions are investigated in a hypothetical bridge crossing in the area of Sulafjorden, central Norway. More specifically, wave conditions at ten positions across the bridge crossing have been derived by means of numerical modelling. The analysis has been carried out by transferring offshore wave conditions to the nearshore area by successive applications of the well-known third-generation wave model SWAN. As input, a very detailed bathymetry of the area, and time series of wind and wave parameters, derived from ERA5 database, have been used. At the target points, long-term time series of directional wave spectra have been used as input for the assessment of the inhomogeneity hypothesis. Various statistical features have been examined including, among others, the seasonal variability, the probability structure, the directionality, the correlation structure, and the long-term wave spectra.

LFCS (Design and Verification of Large Floating Coastal Structures) is a research project, funded by the Research Council of Norway, focused on producing recommendations for design of large coastal structures and developing methods and tools for hydroelastic analysis of coastal structures in spatially inhomogeneous environmental conditions and bathymetry. This paper provides a presentation of the project, and a summary of the related review work on environmental, loads, structural, mooring and physical scaled model tests. Focus is set on floating bridges for fjord crossings. Scaled physical model tests for a floating bridge at SINTEF Ocean&#39;s ocean basin (80m x 50m) for March 2020 are in preparation and it is expected that highlights of this activity can also be presented during the presentation at the conference.

Experimental and numerical study of the response of the offshore combined wind/wave energy concept SFC in extreme environmental conditions Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively. Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in LJMU Research Online to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain. The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Ce travail n'aurait pu être possible sans le soutien et les conseils avisés de nombreuses personnes. Je remercie en premier lieu mon directeur de thèse, Michel Benoit du laboratoire d'Hydraulique Saint-Venant, et mon co-encadrant de thèse, Pietro Bernardara d'EDF Energy R&D UK, de m'avoir suivi pendant ces années. Leurs conseils, leur expertise et le temps qu'ils m'ont consacrés m'ont été très précieux. Je considère avoir eu beaucoup de chance de pouvoir travailler avec eux. Je remercie l'ensemble des membres du jury pour le temps qu'ils m'ont consacré et les échanges techniques que nous avons pu avoir. J'espère que l'on pourra continuer à disserter sur ce sujet dans le futur. Je remercie aussi vivement le SHOM, Gaël André, Camille Daubord, Gwenaële Jan et Ronan Pronost, pour le travail effectué pour la mise à disposition des observations de niveau d'eau et des prédictions de marée, pour leur réactivité et les nombreux conseils qu'ils ont pu m'apporter. C'est en discutant et en partageant que j'ai pu avancer. Parmi les nombreuses personnes qui m'ont aidé à un moment ou un autre, il y a : -François Bouttes et Anne Souquière lors de leur passage au Cerema, -Marc Andreewsky et Jérôme Weiss d'EDF R&D, -Luc Hamm et Franck Mazas d'ARTELIA, -et Marc Prevosto de l'Ifremer. Merci à vous, et merci aussi à tous ceux que j'ai oubliés de citer. Je remercie aussi le Cerema et la DGPR de m'avoir offert l'opportunité de conduire cette thèse. Je remercie en particulier au Cerema mes collègues de la division Hydraulique et Sédimentologie, Guy Amis, François Bouttes, Alain Le Berre, Nathalie Metzler et Ronan Sanquer, d'avoir pris le relais sur de nombreuses tâches et missions afin que je puisse me libérer pour la thèse. Pour finir, et c'est peut-être le plus important, je remercie Marion, ma femme, de m'avoir toujours soutenu, et mes parents de m'avoir permis d'arriver jusque-là.

Pour caractériser le risque de submersion marine, il est très important d&#39;avoir une connaissance précise des lois de distribution des niveaux d&#39;eau marins, et plus particulièrement des niveaux d&#39;eau extrêmes. En effet ce sont eux qui sont à l&#39;origine des conséquences les plus dramatiques. Le programme de recherche mené au cours de cette thèse a été financé par le Ministère de l&#39;Écologie, du Développement Durable et de l&#39;Énergie. L&#39;objectif final est de fournir des valeurs de référence de niveau d&#39;eau marin le long des côtes françaises, par le biais d&#39;une méthode d&#39;analyse statistique des extrêmes. Ces niveaux comprennent les trois composantes suivantes : la marée, la surcote météorologique et le wave set-up. Le principe de base utilisé est le suivant : une analyse statistique est effectuée aux ports où la donnée marégraphique est disponible, puis le résultat est interpolé entre les ports. Différentes approches sont testées. Les points suivants...

Pour caracteriser le risque de submersion marine, il est tres important d&#39;avoir une connaissance precise des lois de distribution des niveaux d&#39;eau marins, et plus particulierement des niveaux d&#39;eau extremes. En effet ce sont eux qui sont a l&#39;origine des consequences les plus dramatiques. Le programme de recherche mene au cours de cette these a ete finance par le Ministere de l&#39;Ecologie, du Developpement Durable et de l&#39;Energie. L&#39;objectif final est de fournir des valeurs de reference de niveau d&#39;eau marin le long des cotes francaises, par le biais d&#39;une methode d&#39;analyse statistique des extremes. Ces niveaux comprennent les trois composantes suivantes : la maree, la surcote meteorologique et le wave set-up. Le principe de base utilise est le suivant : une analyse statistique est effectuee aux ports ou la donnee maregraphique est disponible, puis le resultat est interpole entre les ports. Differentes approches sont testees. Les points suivants...

Newly exposed concepts of POT declustering within the GPD-Poisson model are applied to the joint probability of tide and surge for determining extreme sea levels, as a variation of the Revised Joint Probability Method (RJPM, Tawn and Vassie, 1989). A mixture model is proposed for the meteorological residual (surge) component with a non-parametric (empirical) density for the bulk values and parametric models for both the lower and upper tails. In particular, a distinction is made between values observed at regular time steps, called sequential values, and the clusters of extreme values, or events, on which the statistical extrapolations are performed. The sea level distribution is obtained by convolution of the tide and surge density functions. Confidence intervals are also proposed. This model is applied to the case study of Brest, France using both hourly and high water values. Two methods for handling tide-surge interaction are presented and discussed and a comparison with a direct approach is made.

İzmir İli Çeşme İlçesi yerleşimi kıyılarında 38 yıllık bir süreç içerisinde alan kullanımında gözlenen zamansal değişimler uzaktan algılama yöntemleri kullanılarak değerlendirilmiştir. Topografik haritalar ile 1957, 1976 ve 1995 yıllarına ait hava fotoğraflarından yararlanılarak 8 alan kullanım kategorisi temelinde alan kullanım kategorileri büyüklüklerinin zamansal değişimleri hesaplanmıştır. Alan kullanım kategorilerinin baskınlıkları 1km2‟lik (1kmx1km) grid haritasının alan kullanım kategorileriyle sorgulanması soncunda elde edilmiştir. Sorgulamalar sonucunda; incelenen üç dönem içerisinde doğal bitki örtüsü ve tarım alanı kullanımlarında azalma, yerleşim alanı kullanımlarında ise artış belirlenmiştir. Bu alan kullanım kategorilerinin baskınlık değerleri incelendiğinde ise; doğal bitki örtüsü baskınlığında belirgin bir değişim gözlenmezken, yerleşim alanları baskınlığında belirgin bir artış ve tarım alanları baskınlığında ise belirgin bir azalma saptanmıştır.

Submarines which can change the direction of a war are unique units of a navy. Even little differences in naval technology between the sides provided great advantages to the superior side during the World War II. As small techological differences can have big advantages, the design stage of such critical watercrafts are of great significance. If the design stage of a submarine is successfully fulfilled in terms of hydrodynamic and technological aspects, low resistance at high velocities are achieavable, which makes submarines more effective. Submarine hull have conventional form types; parallel middle body, fore and aft body having smooth curves. In the present study, in order to get a better understanding of hydrodynamic characteristics of these watercrafts, 3 groups of bare hull submarine models which Corresponding Author: Metin Kemal GÖKÇE J OURNAL Kükner et al. / JEMS, 2017; 5(4): 348-360 DOI ID: 10.5505/jems.2017.65487 Original Research (AR) Received: 21 December 2016 Accepted:...

A generic module in which tides, surges and waves are incorporated has been developed, tested Ž and prepared for dissemination within the framework of the MAST III PROMISE PRe-Oper-. ational Modelling In the Seas of Europe project. Two existing pre-operational numerical models, a wave model and a hydrodynamic model, were incorporated into a coupling framework that allows an efficient exchange of information between them. Minimal adaptation of the models was needed. The module has then been implemented and applied to the North Sea, then a series of experiments were performed to investigate the sensitivity of waves and surges to coupling. These experiments show that the sensitivity of waves to coupling increases from deep to shallow water. The sensitivity of surges is more uniformly distributed. The sensitivity of surges to coupling along the Spanish coast was also studied. The model results were less sensitive than in the North Sea. This is explained by the relative importance of the two forcing components, the atmospheric pressure and the wind stress, in both areas.

We analyse the effects of coastal defence structures, mainly low crested (LCS), on the surrounding intertidal and subtidal infaunal assemblages and mobile fauna. The results summarise joint studies within the DELOS project in Spain (Mediterranean Sea), Italy (Adriatic Sea) and UK (English Channel and Atlantic Ocean). We demonstrate that univariate analysis did not generally identify LCS impacts, but multivariate analyses did, this being a general trend across all locations and countries. Changes in sediment and infauna seem to be inevitable and usually tend to induce negative changes, particularly on the landward side and in the presence of additional structures or after beach nourishment. The consequences of LCS construction always depend on the response of the assemblages inhabiting a given region. However, to assess the ecological importance of the induced changes and to provide additional monitoring criteria, likely indicator species should be taken into account. The presence of species either coming from the new hard bottoms or associated to physical disturbances is viewed as a negative impact, while the potential nursery role of LCS is a positive one. The combined use of monitoring and forecast models allows to identify these impacts and may play a relevant role in mitigation protocols. Finally, our work supports the feasibility of introducing design criteria tending to facilitate a positive evolution of the assemblages surrounding the structures once the changes due to the presence of the LCS are completed and the new situation tends to become more stable

In the framework of the LEAP 2017 exercise, two dynamic centrifuge tests on a gentle slope of saturated Ottawa-F64 have been performed at the IFSTTAR centrifuge. These tests were conducted in parallel with other tests performed in nine other centrifuge centers. The objectives were to compare the experimental results, e.g., effect of the experimental procedure or of test parameters on the results, and to provide a database for numerical modeling. In this framework, all the tests were performed on the same prototype geometry and the first base shaking was a 1 Hz ramped sine with an effective amplitude of 0.15 g at the prototype scale. Among some of the tests performed in the various centrifuge facilities, several parameters were modified, such as the density and the second input motion, in order to study their impact on the slope behavior when it is subjected to base shaking. This paper details the procedure followed at the IFSTTAR center for the buildup of dense sand and medium loose sand models and the deviations from the specifications provided by the leaders of the LEAP-UCD-2017 program. The main deviations are, for both tests, the absence of the measurement of the saturation degree and, for the first, the characterization of the soil properties with CPT test and bender element measurements during the test. Some results of the tests performed are briefly presented such as the acceleration, pore pressure buildup, and the deformation of the slope surface. S. Escoffier (*) IFSTTAR,

The research area, which includes five villages, namely Botubarani, Huangobotu, Biluango, Modelomo, and Botutonuo, is located on the south coast of Bone Bolango Regency. People in the coastal area still use shallow well water as a clean and drinking water source. The primary constituent lithology on the coast is limestone, so research on limestone is very important to support community expectations in the environmental field. For this reason, this research aims to assess the potential of limestone in the five villages as a groundwater reservoir rock based on the type and quality of porosity. This research will create a geological conservation area as a groundwater recharge area. The research methods to achieve the objectives consisted of field surveys and laboratory analyses. The laboratory analysis method includes the petrographic and specific gravity and water absorption test methods of coarse aggregate. Based on the research results, the site comprises four types of limestone: wackestone, packstone, rudstone, and boundstone. The four types of limestone have different porosities. The fabric selective porosity type is intercrystalline and moldic, while the non fabrnonfabricve porosity type is vuggy and channel. The porosity quality at the research ___location is divided into two levels, namely large porosity and medium porosity. These two levels of porosity quality make the potential of limestone in the study area as a groundwater reservoir rock very large. With the potential of limestone as a reservoir rock, the distribution of limestone can be used as a geological conservation area for groundwater recharge, so it must be preserved.

To protect scour around an offshore breakwater, prediction of scouring potential are desirable. In this study, scouring pattern by changing the alignment of an offshore breakwater has been investigated with subjected to uniform steady currents, using a 2-D numerical model such as DHI-MIKE21 module. Hydrodynamic analysis have been carried out for an offshore detached breakwater structure to simulate the flow field using Hydrodynamic (HD) model and sedimentation pattern using Sand Transport (ST) model. The calibrated model setup has been used for predicting the flow and scour conditions by changing alignment of an offshore detached breakwater for the following cases, viz., Case-I: an offshore breakwater oriented perpendicular to shoreline, Case-II: an offshore breakwater oriented parallel to shoreline, and Case-III: an offshore breakwater oriented 45° to shoreline. The simulated results show that by changing the orientation of an offshore breakwater with predominant current speed, the scouring can be minimized near the structure effectively. Moreover, it can be used as one of suitable shoreline protection methods to avoid shoreline erosion.

Six years after the catastrophe of the February 27th and 28th, 2010, this work aims at showing the mechanisms of a natural disaster which had not been really foreseen by the local populations, their elected representatives and the French State. Among the causes explaining the heavy death and material toll of the Xynthia storm, the fact that they did not take into account the historical experience largely explains the increase in the exposure of the littoral societies to the risks since the end of the World War II.

Six years after the catastrophe of the February 27th and 28th, 2010, this work aims at showing the mechanisms of a natural disaster which had not been really foreseen by the local populations, their elected representatives and the French State. Among the causes explaining the heavy death and material toll of the Xynthia storm, the fact that they did not take into account the historical experience largely explains the increase in the exposure of the littoral societies to the risks since the end of the World War II. For the lack of integrated research associating the exact sciences (climatology, oceanography, modeling, etc.) and social sciences, in particular the history, in France, the results which follow proceed mainly of the studies led within the framework of the historical report of inquiry (remained dead letter since) returned to the French Parliament on July 4th, 2010 and the European project FP 7 RISC-KIT (Impact strength-Increasing Strategies for Coastal-toolKIT)

Grain size distributions are traditionally analyzed using empirical percentiles (e.g., Folk and Ward, 1957), but analytical models offering direct parameter control remain scarce. In this paper, a new inverse logistic function is introduced that extends the approach of Tauber (1997) and explicitly includes parameters for mean grain size (ϕ50), sorting (so), skewness (sk) and kurtosis (KG). The function combines hyperbolic tangent (tanh) and arctangentsquared (arctan 2) terms to model asymmetric sorting and distribution peakedness. The function provides a unified framework for sediment characterization, reducing reliance on empirical percentile calculations.

Recent field studies have increasingly recognized the importance of tides in dominating the coral reef hydrodynamics. Aside from the tidal level, it is also important to evaluate the effect of tidal current on wave breaking over coral reefs. In this study, a series of laboratory experiments were performed in a wave-current flume in the presence of both flooding and ebbing tides. Experimental results are reported for a variety of combined wave-current conditions based on an idealized barrier reef model. Results analyses show that the relative reef-flat submergence (the ratio of reef-flat submergence to deep-water wave height) is a key parameter to characterize such breaking-wave characteristics as the breaker type, the breaking ___location, the surfzone width, and the breaker depth index. The influences of the current flowrate on the breaking ___location, the surfzone width, and the breaker height index appear to be significant within our tested ranges. Empirical formulas to predict these characteristics in the existing literature are also improved to account for the current effect.

The coastal region is characterized by dynamic changes in its coastline, which can be attributed to various factors. However, the main causes of change along the Gresik coast have yet to be thoroughly studied. Therefore, this research aims to examine the patterns of coastline change along the Gresik coast around the Madura Strait and the influence of wind-generated waves on them. Specifically, the study focuses on four coastal zones: Ujung Pangkah, Sidayu, Bungah, and Manyar districts. The research utilizes satellite imagery and geographic information systems (GIS) as well as methods for calculating ocean waves to analyze the coastline change patterns. The study also examines the impact of ocean wave energy on coastal abrasion and accretion. The findings revealed that the accretion rate in the study area was higher than the erosion rate. The accretion in the coastal area of Gresik is attributed to the flow of the Bengawan Solo River, which carries sediment from upstream. The accretion and abrasion areas for the entire period from 2002 to 2019 were 1063.16 ha and 425.23 ha, respectively. The study also found that the mangrove areas exhibit a higher rate of accretion than abrasion, indicating their potential as a reliable indicator of the effects of sea level rise resulting from global warming. This study revealed that the northern part of Ujung Pangkah District and Bungah District experienced the highest abrasion patterns, whereas no abrasion was observed in Sidayu District. Between 2002 and 2019, the abrasion areas in Ujung Pangkah and Bungah districts totaled 243.96 ha and 178.29 ha, respectively. Windgenerated waves were likely the primary cause of the abrasion in these areas, though other factors may also have contributed to coastline changes. It is essential to consider these factors for effective coastal management in the region.

Deze managementsamenvatting is gegoten in de vorm van meegevers over interactieve kennisprogrammering voor (in eerste instantie) de ZonMw-organisatie. De meegevers zijn gedestilleerd uit de in dit document beschreven eigen leerervaringen en hebben een brede reikwijdte: gezondheidszorgonderzoek is immers niet onderscheidend in zijn gebruiksgerichtheid. ZonMw-document -Interactieve kennisprogrammering Leerervaringen uit het programma Gezondheidszorgonderzoek juli 2014

Saltmarshes have the potential to protect coastal communities from the impact of waves caused by severe storms. While recent developments in numerical models are enhancing the simulation of wave-vegetation interactions, the estimation of the drag coefficient (C d ), used to account for the reduction of wave energy by vegetation, is still a source of uncertainty. In this study, we use a unique combination of field measurements (wave parameters, topo-bathymetric survey and vegetation characteristics) and numerical modelling (XBeach) to evaluate the significance of C d for calculating wave attenuation by vegetation, and ultimately, improve the representation of the wave propagation across these ecosystems. Wave height propagation simulated by five empirical C d formulations, including Jadhav 2012, Anderson & Smith 2014, Garzon 2018 (based on Reynolds [Re] and Keulegan-Carpenter [KC] numbers) and Ozeren et al 2014, was evaluated by comparing against wave heights collected at different locations of two saltmarshes of the Chesapeake Bay during two different storms. This analysis revealed that: 1) Garzon 2018 (based on Re number) and Anderson & Smith 2014 formulations provided the most reliable results (relative bias lower than 20%), especially at the first 100 m across the vegetation field; 2) Results provided by Garzon 2018 (based on KC) formulation yielded relative bias lower than 30%, and it mainly overestimated wave heights; 3) Jadhav 2012 simulations clearly underestimated wave heights, showing relative bias up to -60%; and 4) Ozeren et al 2014 (currently implemented in the model) simulations highly overestimated wave heights over the marsh field and displayed a large scatter. Finally, the validated formulation (Garzon 2018, based on Re number) and vegetation characteristic measurements collected during the fall and winter were employed to explore the seasonal coastal protection variability of these saltmarshes. Our simulations indicated that under similar hydrodynamic conditions, marshes offered between 15% and 30% less protection against waves in the winter than in fall. However, while saltmarshes would provide additional coastal protection from hurricanes in comparison to nor'easters (cool-season extratropical cyclones), we demonstrated that the marshes still offer more protection than non-vegetated fields in both seasons in these locations.

Faecal bacteria exist in both free-living and attached forms in estuarine waters. The deposition of sediments can take faecal bacteria out of the water column and to the bed. The sediments can subsequently be re-suspended to the water column, which can then lead to re-suspension of the faecal bacteria of the attached forms back to the water column. Therefore, the fate and transport of faecal bacteria is highly related to the governing sediment transport processes, particularly where these processes are significant, such as the Severn Estuary, UK. However, little attempt has been made to model such processes in terms of predicting the impact of the sediment fluxes on faecal bacteria levels. Details are given of the refinement of a numerical model of faecal bacteria transport, where the sediment transport processes are significant. After testing the sediment-bacteria interaction model favourably against known results in previous study, the model was applied to the Severn Estuary and Bristol Channel, UK, to investigate the impact of suspended sediment fluxes on the corresponding faecal bacteria transport processes. The model predictions have proved to be encouraging, with the results being compared to a traditional faecal bacteria modelling approach, where sediment bacteria interactions were not included. The new model provides improved predictions of faecal bacteria concentrations when sediment transport is included and for the Bristol Channel Severn Estuary it can be seen that the effects of the sediments on the bacterial levels in the water column can be significant.

The Miles' theory of wave amplification by wind is extended to the case of finite depth h and a shear flow with (constant) vorticity Ω. Vorticity is characterised through the non-dimensional parameter ν = ΩU 1 /g, where g the gravitational acceleration, U 1 a characteristic wind velocity and k the wavenumber. The notion of 'wave age' is generalised to account for the effect of vorticity. Several widely used growth rates are derived analytically from the dispersion relation of the wind/water interface, and their dependence on both water depth and vorticity is derived and discussed. Vorticity is seen to shift the maximum wave age, similar to what was previously known to be the effect of water depth. At the same time, a novel effect arises and the growth coefficients, at identical wave age and depth, are shown to experience a net increase or decrease according to the shear gradient in the water flow.

The effects of the feedback between the changing coastal morphology and the wavefield on the generation and propagation of large scale (O(1-10 km)) shoreline sand waves is examined with a quasi-2D morphodynamic model. Traditional shoreline change models do not include this feedback and are only able to describe diffusion of shoreline sand waves and furthermore they are unable to describe migration. It is found with the present model that if there is a dominant littoral drift, the feedback causes downdrift migration of coastline features no matter if they grow or decay. Consistently with previous studies, simulations show that a rectilinear coastline becomes unstable and sand waves tend to grow spontaneously from random perturbations, if the wave incidence angle is larger then about 42o (θc) at the depth of closure (high angle wave instability). The initial wavelengths at which the sand waves develop are 2-3 km and this is similar to previous linear stability analysis. The implicatio...

Observations of waves and setup on a steep, sandy beach are used to identify and assess potential applications of spatially dense lidar measurements for studying inner-surf and swash-zone hydrodynamics. There is good agreement between lidar-and pressure-based estimates of water levels (r 2 5 0.98, rmse 5 0.05 m), setup (r 2 5 0.92, rmse 5 0.03 m), infragravity wave heights (r 2 5 0.91, rmse 5 0.03 m), swell-sea wave heights (r 2 5 0.87, rmse 5 0.07 m), and energy density spectra. Lidar observations did not degrade with range (up to 65 m offshore of the lidar) when there was sufficient foam present on the water surface to generate returns, suggesting that for narrow-beam 1550-nm light, spatially varying spot size, grazing angle affects, and linear interpolation (to estimate the water surface over areas without returns) are not large sources of error. Consistent with prior studies, the lidar and pressure observations indicate that standing infragravity waves dominate inner-surf and swash energy at low frequencies and progressive swell-sea waves dominate at higher frequencies. The spatially dense lidar measurements enable estimates of reflection coefficients from pairs of locations at a range of spatial lags (thus spanning a wide range of frequencies or wavelengths). Reflection is high at low frequencies, increases with beach slope, and decreases with increasing offshore wave height, consistent with prior studies. Lidar data also indicate that wave asymmetry increases rapidly across the inner surf and swash. The comparisons with pressure measurements and with theory demonstrate that lidar measures inner-surf waves and setup accurately, and can be used for studies of inner-surf and swash-zone hydrodynamics.

The performance of a linear depth inversion algorithm, cBathy, applied to coastal video imagery was assessed using observations of water depth from vessel-based hydrographic surveys and in-situ altimeters for a wide range of wave conditions (0.3 < significant wave height < 4.3 m) on a sandy Atlantic Ocean beach near Duck, North Carolina. Comparisons of video-based cBathy bathymetry with surveyed bathymetry were similar to previous studies (root mean square error (RMSE) ¼ 0.75 m, bias ¼ À0.26 m). However, the cross-shore locations of the surfzone sandbar in video-derived bathymetry were biased onshore 18-40 m relative to the survey when offshore wave heights exceeded 1.2 m or were greater than half of the bar crest depth, and broke over the sandbar. The onshore bias was 3-4 m when wave heights were less than 0.8 m and were not breaking over the sandbar. Comparisons of video-derived seafloor elevations with in-situ altimeter data at three locations onshore of, near, and offshore of the surfzone sandbar over ~1 year provide the first assessment of the cBathy technique over a wide range of wave conditions. In the outer surf zone, video-derived results were consistent with long-term patterns of bathymetric change (r 2 ¼ 0.64, RMSE ¼ 0.26 m, bias ¼ À0.01 m), particularly when wave heights were less than 1.2 m (r 2 ¼ 0.83). However, during storms when wave heights exceeded 3 m, video-based cBathy over-estimated the depth by up to 2 m. Near the sandbar, the sign of depth errors depended on the ___location relative to wave breaking, with video-based depths overestimated (underestimated) offshore (onshore) of wave breaking in the surfzone. Wave speeds estimated by video-based cBathy at the initiation of wave breaking often were twice the speeds predicted by linear theory, and up to three times faster than linear theory during storms. Estimated wave speeds were half as fast as linear theory predictions at the termination of wave breaking shoreward of the sandbar. These results suggest that video-based cBathy should not be used to track the migration of the surfzone sandbar using data when waves are breaking over the bar nor to quantify morphological evolution during storms. However, these results show that during low energy conditions, cBathy estimates could be used to quantify seasonal patterns of seafloor evolution.