Center for Harbours and Coastal Studies

Madrid, Spain

Center for Harbours and Coastal Studies

Madrid, Spain
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Kamarianakis Y.,Arizona State University | Ayuso S.V.,Arizona State University | Ayuso S.V.,Center for Hydrographic Studies | Rodriguez E.C.,Center for Harbours and Coastal Studies | Velasco M.T.,Center for Hydrographic Studies
Journal of Hydrology: Regional Studies | Year: 2016

Study region: 43 rivers in Spain with measurement stations for air and water temperatures. Study focus: River water temperatures influence aquatic ecosystem dynamics. This work aims to develop transferable river temperature forecasting models, which are not confined to sites with historical measurements of air and water temperatures. For that purpose, we estimate nonlinear mixed models (NLMM), which are based on site-specific time-series models and account for seasonality and S-shaped air-to-water temperature associations. A detailed evaluation of the short-term forecasting performance of both NLMM and site-specific models is undertaken. Measurements from 31 measurement sites were used to estimate model parameters whereas data from 12 additional sites were used solely for the evaluation of NLMM. New hydrological insights for the region: Mixed models achieve levels of accuracy analogous to linear site-specific time-series regressions. Nonlinear site-specific models attain 1-day ahead forecasting accuracy close to 1 °C in terms of mean absolute error (MAE) and root mean square error (RMSE). Our results may facilitate adaptive management of freshwater resources in Spain in accordance with European water policy directives. © 2016 The Authors.

Diaz-Sanchez R.,Center for Harbours and Coastal Studies | Lopez-Gutierrez J.S.,Technical University of Madrid | Lechuga A.,Center for Harbours and Coastal Studies | Negro V.,Technical University of Madrid
Journal of Coastal Research | Year: 2014

Equations for extreme runup worked out from several experimental studies are compared. Infragraviatory oscillations dominate the swash in a dissipative state but not in intermediate reflective states. Therefore two kinds of equation depending on either significant wave height, H0, or the Iribarren number, ξ0, should be used. Through a sand bed physical model with a uniform sand bed slope, equations are proposed for both beach states, and results are compared with precedent field and physical model experiments. Once the equations are chosen, the time-longshore variability in a medium long term time scale of the foreshore slope is evaluated in two extreme cases relating to the Spanish coast. The Salinas beach on the North coast (Bay of Biscay) displayed a permanent dissipative beach state with small variations in the beach foreshore slope both along the shore and in time, so foreshore slope deviations in a medium-long term period were irrelevant and extreme runup is predicted with the wave height worked out from the design return period. Peñíscola beach on the East coast (Mediterranean sea) displayed an intermediate state. If only time variations are analysed, variations in determining extreme runup are irrelevant. In contrast, significant differences were found when the longshore variations were studied in this Mediterranean beach. © Coastal Education & Research Foundation 2014.

Diaz-Sanchez R.,Center for Harbours and Coastal Studies | Lopez-Gutierrez J.S.,Technical University of Madrid | Lechuga A.,Center for Harbours and Coastal Studies | Negro V.,Technical University of Madrid | Esteban M.D.,Technical University of Madrid
Journal of Coastal Research | Year: 2013

The extreme runup is a key parameter for a shore risk analysis in which the accurate and quantitative estimation of the upper limit reached by waves is essential. Runup can be better approximated by splitting the setup and swash semi-amplitude contributions. In an experimental study recording setup becomes difficult due to infragravity motions within the surf zone, hence, it would be desirable to measure the setup with available methodologies and devices. In this research, an analysis is made of evaluated the convenience of direct estimation setup as the medium level in the swash zone for experimental runup analysis through a physical model. A physical mobile bed model was setup in a wave flume at the Laboratory for Maritime Experimentation of CEDEX. The wave flume is 36 metres long, 6.5 metres wide and 1.3 metres high. The physical model was designed to cover a reasonable range of parameters, three different slopes (1/50, 1/30 and 1/20), two sand grain sizes (D50 = 0.12 mm and 0.70 mm) and a range for the Iribarren number in deep water (ζ 0) from 0.1 to 0.6. Best formulations were chosen for estimating a theoretical setup in the physical model application. Once theoretical setup had been obtained, a comparison was made with an estimation of the setup directly as a medium level of the oscillation in swash usually considered in extreme runup analyses. A good correlation was noted between both theoretical and time-averaging setup and a relation is proposed. Extreme runup is analysed through the sum of setup and semi-amplitude of swash. An equation is proposed that could be applied in strong foreshore slope-dependent reflective beaches. © Coastal Education & Research Foundation 2013.

Sanchez-Gonzalez J.F.,Center for Harbours and Coastal Studies | Sanchez-Rojas V.,Ministry of Public Works | Memos C.D.,National Technical University of Athens
Journal of Hydraulic Research | Year: 2011

An experimental study carried out in a flume to a scale of 1/20 is presented to assess the wave height attenuation induced by submerged meadows of Posidonia oceanica. After examination of the appropriate scaling laws and selection of the model material, an extensive test programme included both regular and random waves. A semi-empirical formulation for estimating the wave height transformation along the meadow is obtained, based on energy conservation and considering that dissipation is only due to drag forces. The latter were linearized to obtain an exponential decay law. The formulation proposed depends on the drag coefficient and includes also an empirical parameter accounting for wave steepness. The model improves previous results and extends its applicability to random waves. The drag coefficient associated to the meadows is found to be better related to the Keulegan-Carpenter parameter than to the Reynolds number. Its value is given also for models proposed by others. © 2011 Copyright International Association for Hydro-Environment Engineering and Research.

Martin Soldevilla M.J.,Center for Harbours and Coastal Studies | Martin-Hidalgo M.,Center for Harbours and Coastal Studies | Martin-Hidalgo M.,Technical University of Madrid | Negro V.,Technical University of Madrid | And 2 more authors.
Coastal Engineering | Year: 2015

The different theoretical models related with storm wave characterization focus on determining the significant wave height of the peak storm, the mean period and, usually assuming a triangle storm shape, their duration. In some cases, the main direction is also considered. Nevertheless, definition of the whole storm history, including the variation of the main random variables during the storm cycle is not taken into consideration.The representativeness of the proposed storm models, analysed in a recent study using an empirical maximum energy flux time dependent function shows that the behaviour of the different storm models is extremely dependent on the climatic characteristics of the project area. Moreover, there are no theoretical models able to adequately reproduce storm history evolution of the sea states characterized by important swell components.To overcome this shortcoming, several theoretical storm shapes are investigated taking into consideration the bases of the three best theoretical storm models, the Equivalent Magnitude Storm (EMS), the Equivalent Number of Waves Storm (ENWS) and the Equivalent Duration Storm (EDS) models. To analyse the representativeness of the new storm shape, the aforementioned maximum energy flux formulation and a wave overtopping discharge structure function are used.With the empirical energy flux formulation, correctness of the different approaches is focussed on the progressive hydraulic stability loss of the main armour layer caused by real and theoretical storms. For the overtopping structure equation, the total volume of discharge is considered. In all cases, the results obtained highlight the greater representativeness of the triangular EMS model for sea waves and the trapezoidal (. nonparallel sides) EMS model for waves with a higher degree of wave development.Taking into account the increase in offshore and shallow water wind turbines, maritime transport and deep vertical breakwaters, the maximum wave height of the whole storm history and that corresponding to each sea state belonging to its cycle's evolution is also considered. The procedure considers the information usually available for extreme waves' characterization. Extrapolations of the maximum wave height of the selected storms have also been considered. The 4th order statistics of the sea state belonging to the real and theoretical storm have been estimated to complete the statistical analysis of individual wave height. © 2014 Elsevier B.V.

Martin-Hidalgo M.,Center for Harbours and Coastal Studies | Martin-Hidalgo M.,Technical University of Madrid | Martin-Soldevilla M.J.,Center for Harbours and Coastal Studies | Negro V.,Technical University of Madrid | And 2 more authors.
Coastal Engineering | Year: 2014

Storm evolution is fundamental for analysing the damage progression of the different failure modes and establishing suitable protocols for maintaining and optimally sizing structures. However, this aspect has hardly been studied and practically the whole of the studies dealing with the subject adopt the Equivalent triangle storm. As against this approach, two new ones are proposed. The first is the Equivalent Triangle Magnitude Storm model (ETMS), whose base, the triangular storm duration, D, is established such that its magnitude (area describing the storm history above the reference threshold level which sets the storm condition), HT, equals the real storm magnitude. The other is the Equivalent Triangle Number of Waves Storm (ETNWS), where the base is referred in terms of the real storm's number of waves, Nz. Three approaches are used for estimating the mean period, Tm, associated to each of the sea states defining the storm evolution, which is necessary to determine the full energy flux withstood by the structure in the course of the extreme event. Two are based on the Jonswap spectrum representativity and the other uses the bivariate Gumbel copula (Hs, Tm), resulting from adjusting the storm peaks. The representativity of the approaches proposed and those defined in specialised literature are analysed by comparing the main armour layer's progressive loss of hydraulic stability caused by real storms and that relating to theoretical ones. An empirical maximum energy flux model is used for this purpose. The agreement between the empirical and theoretical results demonstrates that the representativity of the different approaches depends on the storm characteristics and point towards a need to investigate other geometrical shapes to characterise the storm evolution associated with sea states heavily influenced by swell wave components. © 2013 Elsevier B.V.

Moreno I.,Center for Harbours and Coastal Studies | Del Barrio I.,Center for Harbours and Coastal Studies | Lloret A.,Center for Harbours and Coastal Studies | Perez-Puyol A.,Ministry of Agriculture
Proceedings of the Coastal Engineering Conference | Year: 2012

In 2008, the European Community adopted the Marine Strategy Framework Directive, aiming to achieve or maintain good environmental status in the European marine environment by 2020, applying an ecosystem-based approach to the management of human activities. Spatial information of the distribution of the human activities and their related pressures is essential to accomplish this task successfully. After compiling the available data from official sources, the spatial extent of the land-based and ocean-based human activities that could have an impact on the Spanish marine waters were estimated and mapped using GIS tools. In addition, a series of indexes were created in order to develop a cumulative analysis, taking into account the different relevance of pressures and that single pressures have different intensities. The identification of areas with an accumulation of pressures revealed that it is in coastal waters around big cities where the greater part of the pressures concentrates for each of the five Spanish marine districts. Human impacts emanating from the identified pressures could not be evaluated and this task is proposed to be accomplished in further projects. Nonetheless, the resulting information is considered very useful for managers and technical staff to support not only marine management but also other planning and decision making in Spain.

De La Pena J.M.,Center for Harbours and Coastal Studies | Sanchez Gonzalez J.F.,Center for Harbours and Coastal Studies | Diaz-Sanchez R.,Center for Harbours and Coastal Studies | Martin Huescar M.,Center for Harbours and Coastal Studies
Proceedings of the Coastal Engineering Conference | Year: 2012

Several formulations deduced from empirical studies are available for runup estimation. Scattering is high when applied to practical cases. Through a state of the art best formulations are chosen. These equations are also studied in a physical model carried out in the Laboratory for Maritime Experimentation of CEDEX with three beaches with slopes 1/20, 1/30 and 1/50 and with sand bed. The performance of each formulation is discussed. A new formulation is proposed in order to give more weight to the beach slope thus reducing scatter.

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