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This paper presents the results of morphodynamic modelling and analysis of onshore and offshore sandbar migration based on a depth-integrated approach. The coastal flow was modeled using the Boussinesq equation and the morphological evolution was modeled using the suspended sediment transport equation and bed load formulae based on the instantaneous velocity and acceleration. The proposed model was applied to the accretive and erosive conditions and the model reproduced the onshore and offshore sandbar migration and the formation of a berm around the shoreline reasonably. An analysis of the computed results revealed the following. (i) The vertical flow velocity can affect the suspension time of the sediments considerably and the bottom evolution. (ii) The suspended load is the main contributor to the morphological changes in terms of the quantity and quality, regardless of the accretive or erosive conditions. (iii) Regardless of accretive or erosive conditions, in terms of the time-average, the instantaneous flow velocity and acceleration-based bed load models always yielded an offshore and onshore direction sediment flux, respectively, except in the swash zone. On the other hand, the suspended sediment flux calculated by the advection-diffusion equation results in the sediment transport in either direction depending on the flow field.

This paper deals with the question of how to manage vulnerable coastal systems so as to make them sustainable under present and future climates. This is interpreted in terms of the coastal functionality, mainly natural services and support for socio-economic activities. From here we discuss how to adapt for long term trends and for short terms episodic events using the DPSIR framework. The analysis is presented for coastal archetypes from Spain, Ireland and Romania, sweeping a range of meteo-oceanographic and socio-economic pressures, resulting in a wide range of fluxes among them those related to sediment. The analysis emphasizes the variables that provide a higher level of robustness. That means mean sea level for physical factors and population density for human factors. For each of the studied cases high and low sustainability practices, based on stakeholders preferences, are considered and discussed. This allows proposing alternatives and carrying out an integrated assessment in the last section of the paper. This assessment permits building a sequence of interventions called adaptation pathway that enhances the natural resilience of the studied coastal systems and therefore increases their sustainability under present and future conditions.

The use of a pressuremapping system formeasuring wave impact induced pressures is evaluated in this paper. A set-up and a calibrationmethodology are suggested and employed for thiswork. The system is validated against pressure transducer and load cell measurements and for a range of waves breaking on a vertical seawall. For a large number (120 measurements for each case considered) of breaking and broken waves interacting with the wall, the peak pressure (Ppeak) profiles and the pressure distribution maps reported by the system agree wellwith results acquired using pressure transducers. Although the pressuremapping system tends to underestimate Ppeak, differences on themean of the 3, 5 and 10 highest Ppeak rangewithin±10%, while for themajority of the measurements the error on the integral of the acting pressures (the acting force compared with the force measured by the load cell) ranges within ±20%. It is concluded, that through careful calibration and set-up the pressure mapping system has the capacity to provide pressure distribution maps with a good accuracy. It is not, however, considered to constitute the absolute alternative to pressure transducers and thus a combined use is suggested for applications where a very high level of accuracy is required.

The turbid plume formed at many river mouths influences the adjacent coastal area because it transports sediments, nutrients, and pollutants.; The effects of the main forcings affecting the Ebro turbid plume were analyzed using data obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Aqua and Terra satellites over the period 2003-2011. Composite images were obtained for days under certain river discharge conditions (different flow regimes) and different types of wind (alongshore and cross-shore winds) in order to obtain a representative plume pattern for each situation.; River discharge was the main driver of the Ebro River plume, followed by wind as the secondary force and regional oceanic circulation as the third one. Turbid plume extension increased monotonically with increased river discharge. Under high river discharge conditions (>355 m(3) s(-1)), wind distributed the plume in the dominant wind direction. Seaward winds (mistral) produced the largest extension of the plume (1893 km(2)), whereas southern alongshore winds produced the smallest one (1325 km(2)). Northern alongshore winds induced the highest mean turbid value of the plume, and southern alongshore winds induced the lowest one. Regardless of the wind condition, more than 70% of the plume extension was located south of the river mouth influenced by the regional oceanic circulation.

The applicability of recommendations of the Eurosion project to define a policy to manage coastal erosion has been tested at the “beach” scale in the Mediterranean coast. Thus, a favourable sediment status has been defined for these beaches taking into account their main functions: recreation and protection. Because they act at two different seasons, this status needs to be seasonally defined. For the protection function, the favourable sediment status depends on the level of safety fixed by the manager taking into account the importance of existing infrastructures and, for recreation it depends on the use density of the beach. The concept has been formalized for beach management within a framework where benchmarking plays a crucial role to determine the need of intervention. This has been illustrated for open cell beaches where one of its boundaries can permit variations in the sediment budget and for pocket beaches that act as closed sediment cells.

This paper summarises the main findings of the Conscience research project, whose primary objective was to define and validate, through pilot applications, a methodology to support the implementation, for European coasts, of concepts such as coastal resilience, favorable sediment status, strategic sediment reservoirs and coastal sediment cells. The Conscience conceptual framework to managing coastal erosion has proved to be an efficient tool, because it provides a consistent approach where objective (data) and subjective (desired status) information are analyzed and compared from the standpoint of a consensus target (objective). Moreover, this is done using the best available knowledge and observations, considering always their level of uncertainty, to conduct a sustainable management policy for coastal erosion. The methodology has been tested in field cases from The Netherlands, Poland, Romania, Spain, United Kingdom and Ireland, to cover different time and space scales, together with a wide range of processes and different management objectives.

The main objective of the Conscience project was to develop and test concepts, guidelines and tools for the sustainable management of erosion along the European coastline, based on the best available scientific knowledge and on existing practical experience. Four concepts are potentially capable of providing the nexus between scientific knowledge and management: coastal resilience, coastal sediment cell, favourable sediment status and strategic sediment reservoir. The project has tested the use of these concepts and found that they are useful, provided that they are positioned and linked within a logical structure that we shall call the Conscience “Frame of Reference”, defined in time and space and supported through data and monitoring. Practical experience in six coastal sites in Europe has shown that the use of this Frame of Reference together with these concepts can make management objectives explicit and transparent. It can therefore support the design of an appropriate, resilience based coastal erosion management practice.

This special issue presents the main research results from the SANDS project in Hydralab-III, a research project of the European Union. The papers review the scaling and design of mobile bed tests, the role and limits of conventional and new instrumentation and the extrapolation to full scale. The project has focused on innovative systems of opto-acoustic instrumentation, able to recover water and sediments fluxes at an unprecedented level of accuracy and resolution. The research also included large scale experiments at different scales and a critical comparison of experimental and numerical results to improve the state of the art in Coastal Engineering.

This paper is focussed on the derivation of a set of general scaling laws valid for both beach and dune erosion volumes based on scaling law analysis, existing and new experimental results. This latter experiments concern beach profile changes in three different laboratory flumes using identical wave conditions based on Froude scaling. The experiments with planar sloping beaches have been done at three scales: large-scale Hannover wave flume experiment (beach slope of 1 to 15), medium scale Barcelona wave flume experiment (beach slope of 1 to 15) and small-scale Delft wave flume experiments (beach slopes of 1 to 10, 15 and 20) using an identical wave train of irregular waves (single topped spectrum). The available data sets have been used to derive a general set of scaling laws which is valid for both beach and dune erosion under storm conditions. The morphological time scale depends on the depth scale and the length scale, and only indirectly on the sediment size scale. The analysis of the scaling laws shows that laboratory scale models can be operated at distorted scales, if necessary. Finally, two applications of the scaling laws are presented.

The levels of uncertainty for morphodynamic analysis in the present state of art require field measurements and, whenever possible, large scale mobile bed tests to reproduce what happens in Nature under controlled conditions. Following this idea, the paper will revise the procedure to design reduced scale mobile bed tests, including the criteria for scaling and those for selecting an experimental facility. This will be followed by the description of a set of carefully designed erosion and accretion beach profile tests, carried out at 2 different scales (prototype, large and small scales) and in three different wave flumes in such a way that the results should be fully compatible. From here we shall discuss the fundamental issues about test repeatability, error bounds and the feasibility to extrapolate to other scales. The paper will present next the measurements carried out within the swash zone in one of the flumes. This zone, relatively less studied until recently in the state-of-art, is now the focus of considerable research attention. Its reduced dimensions and the fact that it is alternatively wet and dry will serve to review the advanced observational systems used in the hydraulic tests, and which have allowed recording swash/surf zone processes with an unprecedented level of resolution and accuracy. The paper will end with some discussion about the present and future role of mobile bed tests.

The continuous research and improvement of ocean modelling helps to provide a more sustainable development of coastal and offshore regions. This paper focuses on ocean modelling at the NW Mediterranean using the POLCOMS–WAM model with new developments. The Stokes’ drift effect on currents has been included and the distribution of surface stress between waves and currents has also been considered. The system is evaluated in the NW Mediterranean and an evaluation of different forcing terms is performed. The temperature and salinity distributions control the main patterns of the Mediterranean circulation. Currents are typically small and therefore the modification of waves due to the effect of currents is minimal. However, the wave induced currents, mainly caused by a modified wind drag due to waves, produce changes that become an important source of mass transport. POLCOMS was able to reproduce the main Mediterranean features, its coupling with WAM can be a very useful tool for ocean and wave modelling in the Mediterranean and other shelf seas.

Most of the marine pollution attributable to ship actions is associated with the illicit discharge of oily residues or ballast water, in what is commonly termed operational pollution. In the particular case of ballast water, careless disposal can lead to severe ecological damage, including the irreversible establishment of communities of invasive species. In its 2004 Convention on ballast water management, the International Maritime Organisation defined the measures to be followed to prevent these environmental issues, including the exchange with mid-oceanic water at a minimum distance from the shore. This paper uses two numerical models to analyse the effects of several factors on the dilution of a discharge from a ship moving in the Spanish Mediterranean waters, in order to determine under which conditions the environmental impact of the discharge will be minimum. The results highlight the dual role played by a freshwater plume, which may contribute either to decrease or to enhance the onshoreward transport of the discharged substance, and the relevance of the ship's speed in determining the dilution rates.

The phenomenon of overtopping is traditionally studied for well-emerged harbour structures and often focuses on safety and stability. In this paper laboratory tests are presented and analysed to sharpen the hypothesis that overtopping is capable of changing the horizontal circulation pattern around low-crested structures. A unique data set from laboratory experiments was acquired in the wave basin at Delft University of Technology. The experiments were performed using an emerged impermeable low-crested structure (three freeboards and three different wave conditions for each freeboard) and yielded nine different combinations of set-up and overtopping driving forces. Using this information it was possible to quantify the changes in cross-shore and longshore velocity induced by the overtopping and the set-up changes under the different freeboard and wave conditions described. It is found that overtopping enhances the outgoing flows (longshore velocities parallel to the structure) away from the lee side of the structure and dampens the water level gradient driven flow towards the structure.

The increase in maritime traffic means that ports have to continuously improve their efficiency. This involves reducing the inactivity caused by adverse climatic conditions. Adverse conditions that inconvenience port users include short and long waves. In this paper, the effect of long waves on port operations in Gijon harbor (Spain) is analyzed by means of a numerical model. Short wave propagation inside the harbor was compared with two different combinations of short and long waves. Taking into account the wave heights that limit operations, the periods of inactivity due to waves were computed for every dock. The results show that the harbor offers very good protection against wind (short) waves. Nevertheless, the port's inefficiency is significantly increased if long waves are present in the wave trains affecting the harbor. This illustrates the importance of taking into account long waves in port management. Finally, other limited effects of long waves in harbor environmental management issues are pointed out.

This paper analyses 10 years of wave data from the Mediterranean Spanish (Catalan) coast considering the mean wave climate and storm events from the standpoint of wind-wave momentum transfer and wave prediction. The data, registered by a buoy at about 12 km from the coastline, revealed two main groups of wave storms, with NW and E directions. NW storms correspond to a fetch-limited situation since the intense wind blows from land. Low-pressure centres located over the Mediterranean Sea produce easterly storms. Near the coast the eastern winds from the sea are replaced by NW winds coming from meteorological patterns over northern Spain and south-western France. Wave storms are classified and studied to obtain their main features (including spectral width, wave length, wave age and bimodality) and discussed in terms of wind-wave momentum transfer for operational wave predictions. Observations show a complex coastal wave climate. Fetch-limited storms presented smaller spectral widths while varying wind situations presented larger widths due to the presence of bimodal spectra. These wave features are highly relevant for wind–ocean momentum transfer and, thus, for current and wave predictions. The spectral width proved to be a good indicator of sea complexity and is thus applicable for improved wind drag estimations. A new drag coefficient formulation is proposed, based on existing wind dependent drag expressions, but including also spectral wave properties (a spectral width parameter) that highlights the characteristics of wind-wave generation under pre-existing swell. Such a formulation, once properly validated with field observations, is expected to improve wind-wave predictions.

A model is presented to simulate the long-term (decadal) evolution of microtidal spit-barrier systems. The model has been derived from the analysis of coastal processes taking place along the Trabucador-La Banya complex in the Ebro delta (Spanish Mediterranean coast). It is composed of two submodels to simulate the evolution of the seaside and bayside barrier shorelines. The outer coast submodel is of the one-line type, but formulated in curvilinear coordinates to reproduce the evolution of strongly curved coasts, which is a common configuration for spits. The model makes use of a long-term parameterization of the longshore sediment transport rate, which is formulated in terms of a morphological wave and a local transport constant. The inner coast submodel is based on a morphological equilibrium approach. It considers the overwash transport to be the dominant driving term contributing to the sediment budget of the inner coast. It makes use of the concept of critical barrier width to estimate the conditions under which overwash is able to contribute to bayside shoreline accretion. The model has been verified/calibrated for the Trabucador-La Banya system and it has been used to simulate its evolution under different climatic scenarios.

A steady-state quasi-3D finite element model is forced with in situ measured wind conditions in order to obtain an estimate of the mean circulation off the Ebro delta and to assess its consequences upon water fluxes. The model is spectral in the vertical direction and is run with a reduced number of vertical degrees of freedom (modes). The boundary conditions prescribed on the ocean contours account for the existence of a slope jet. The hypothesis is that the direct wind forcing on the upper layer and the shelf mesoscale circulation are the main mechanisms driving the flow in the area and that it should be possible to reproduce the main current features even in the vicinity of the Ebro river mouth with this relatively simple model setup, as the usual river freshwater discharge rates are rather low. This is clearly different from the case of other region of freshwater influence systems, in which the river plume dynamics and the related density currents play relevant roles. The model results are compared with surface drifter trajectories obtained during field campaigns.

[EN] In this paper the results of two field campaigns (Ebro-I and Ebro-II) carried out during the spring and summer of 1997 are used to examine the differences in nutrient behaviour between the estuary and plume of the Ebro River in the Spanish Mediterranean coast. These campaigns are representative of typical conditions existing during a rainy season (spring) and a dry one (summer). In the estuary, the most determinant processes are nutrient transport-strengthened by agricultural irrigation-and phytoplankton death in the surface, followed by its sinking and breakdown below the saline interface. These processes lead to higher levels of ammonium and phosphorus (SRP) below the halocline. In the river plume region the most important process is the phytoplankton uptake which leads to very low levels of SRP in the points of higher salinity. Both ammonium and SRP are always lower below the saline interface than in areas adjacent to the river mouth. (C) 2002 Elsevier Science Ltd. All rights reserved., The authors wish to acknowledge the support given to this work by the projects FANS and PIONEER fromthe EC MAST-III Research Programme (contracts No. MAS3-CT95-0037 and MAS3-CT98-0170, respectively) and the CYTMAR Programme from the Spanish Comision Interministerial de Ciencia y Tecnolog ! !ıa (project MAR96-1856). The collaboration of all the people who endured the fieldwork is also strongly appreciated as well as the affability of the Confederacion Hidrogr ! afica del Ebro supplying ! river discharge data and the Centro de Estudios de Puertos y Costas (CEDEX) lending some of the equipment employed during the field campaigns.

Due to the limited supply of sediment from the Ebro river, its delta is mainly subject to reshaping processes in the form of alongshore alternation of erosive and accretive coastal stretches, without a significant change in the overall subaerial surface of the delta. The main agents presently forcing these processes (waves and mean water-level oscillations) are analysed in detail as a function of their contribution to coastal processes. In this manner, waves are characterised in terms of short-term/seasonal changes, longshore sediment transport pattern, long-term cross-shore transport at the shoreface and storm impacts. Although the study area is a microtidal one, and waves are the main agent forcing coastal evolution at yearly scales, mean water-level oscillations (meteorological tides and long-term relative mean sea-level variations) play a non-negligible role. Additionally, a joint analysis of waves and storm surges has been done in order to characterise conditions inducing an ‘impulsive’ type of coastal response. At last, the classical ternary classification of deltas has been applied in a ‘dynamical way’ by considering the river vertex in terms of the variation in sediment supply. Moreover, the effects of considering mean water-level variations (other than tides) on the deltaic classification has also been tested. The inclusion of RSLR influence becomes relevant for ‘river-independent’ deltas since it indicates the inability of the delta to withstand it. The main problem to include this agent in the ternary classification is that RSLR is more of a ‘passive’ factor, whereas the other considered agents are ‘active’ in the sense that they induce more perceivable morphological processes.

The aim of this paper is to present an analytical expression for the vertical distribution of the correlation between the horizontal (ũ) and vertical (w) wave velocity components. This quantity, 〈ũw〉, which appears explicitly in the time-averaged momentum balance equations, has been shown to play an important role in the vertical distribution of wave-induced currents. The proposed formulation for 〈ũw〉 is based on an identity that relates the effective (wave) shear stress 〈ũw〉 to the effective (wave) normal stresses (〈ũ〉2 and 〈w〉2) and to the vorticity of the oscillatory flow \ gw. This general expression has been applied to simplified situations and has been shown to degenerate into other existing formulations with comparable simplifying assumptions, viz. irrotational waves in shallow water over an arbitrary bottom topography and breaking waves over a horizontal bottom. The model has also been applied to the case of waves interacting with a depth-varying current over a horizontal bottom, in which preliminary results have been obtained for a simplified situation invoking linear (small-amplitude) wave theory.

Measurements of shoreline displacements along the Ebro delta coast have been used to estimate the medium-term evolution of the coastline. Aerial photographs and beach profile surveys covering the last 35 years have been used. Shoreline data obtained from beach surveys have been analysed using a linear regression technique in order to filter out short-term components. The medium-term scale has been derived from the asymptotic trend with this filtered analysis. Results have been compared with trends observed in the past and a similar qualitative behaviour has been found. Rates of change have decreased because the shoreline has slowly evolved towards a more stable configuration. A profile closure depth of 7 m has been estimated based on morphological changes in the submerged profiles and then used to convert shoreline displacements into yolume changes. From these, a medium-term sediment budget has been calculated. Based on the available evidence it has been assumed that these changes are mainly due to wave-induced longshore transport gradients. Assuming proper boundary conditions, the net longshore transport scheme has been estimated for each hemidelta. The results obtained using this method are in good agreement with the longshore transport rates predicted by well-known transport formulae.

A descriptive investigation on the wind wave climate off the Ebro delta has been conducted on the basis of time series of data collected after 1978. Sea states have been classified into phenomenological cathegories according to available directional data. For selected records, illustrating the different wave conditions, statistical and spectral analyses have been performed so as to assess the short-term characteristics of the wave climate. Regarding the longer-term evolution, correlations among the main wave parameters have been established. Theoretical probability distributions have been fitted to the observed frequency histograms in order to complete the description of the average wave climate. Furthermore, some statistics of extreme wave heights have also been considered.