18 research outputs found

    Geomorphology, beach classification and seasonal morphodynamic transition of a Mediterranean gravel beach (Sardinia, Gulf of Cagliari)

    Get PDF
    This paper presents an innovative multi-thematic map (1:2500) that integrates morpho-sedimentological data, hydrodynamic processes, seasonal morphodynamic transitions and the distribution of the benthic habitat of a Mediterranean microtidal, wave-dominated gravel beach system. It is part of a larger cartography of coastal areas, and is based on an interdisciplinary sea-land approach that is applicable worldwide and aims to facilitate coastal management practices and future scientific research. The applications to coastal management include: the facilitation of coastal vulnerability assessments; easy-to-access, up-to-date digital geospatial data; and baseline studies for the future assessment and monitoring of environmental changes. The main environmental features that control the marine processes of this gravel beach appear to be linked to geological and morphological contexts such as the presence of the river mouth, the outcropping of a beach-rock along the coastline, the deposition of gravelly sediment in the beachface and the seagrass cover

    PRE-FEASIBILITY STUDY OF A WAVE FARM OFFSHORE ALGHERO: RESOURCE, TECHNOLOGY AND PLANNING CONSIDERATIONS

    No full text
    Marine renewable energy could represent part of the solution to climate change by producing clean energy from high density sources like waves, without CO2 emissions. Although the highest wave resource is located in the oceans, the Mediterranean Sea potential represents a viable resource and should not be ignored, particularly for countries with long coasts and numerous islands such as Italy. The case study of Alghero, in Sardinia has been chosen because it is subjected to the most powerful wave resource in the Mediterranean Sea. The methodology to undertake a pre- feasibility assessment of MREP is tested in Alghero, but is applicable elsewhere. Its energetic wave climate has been monitored through an 18-year time series from a wave buoy located offshore of Alghero, for the period 1989-2008. In this work three main aspects are covered, to reach a site selection for the best location of WECs in the study area. Firstly, the wave resource assessment offshore of Alghero is carried out on an annual, and more detailed monthly base. Secondly, the performances of R115 (fully developed) WEC, in shape of power matrix, are applied to the resource assessed. The annual electricity output producible by the farm is calculated and related to the city’s household electricity requirements. Thirdly, marine planning considerations are taken into account, through site visits, to evaluate potential conflicts with other sectors user of the marine area (e.g. fishery, natural conservation and tourism sectors) and to identify the logistic information for WEC installation. These foundlings have been summarized in geo-referenced maps for WEC site selection, resulting into two most promising areas and corroborating the validity of the methodology proposed

    An Assessment of Swash Excursion Predictors using Field Observations

    No full text
    Accurate predictions of swash excursion are fundamental for improving the understanding of swash zone dynamics and for coastal management and hazard applications. Researchers have provided several formulas for predicting the swash excursion on sandy beaches. However, the problem of the universality of these formulas is still open. In fact, it is not clear whether the existing formulations are applicable to a wide range of beaches and wave conditions. This study verifies 13 existing swash (total, incident and infragravity) formulations using 13 published experiments (636 swash measurements). The experiments were carried out on beaches worldwide (dissipative intermediate and reflective) under a wide range of wave conditions (including extreme events). Results show that formulas behave differently with under and over prediction. However, some trends can be recognized, which are indeed critical for coastal hazards and management applications: generally, for large swash events (swash >1.5 m) large scatter are found for all formulas. During extreme conditions (swash>2.5 m) total and incident swash are strongly underestimated, while infragravity swash varies for each formula. The maximum errors and the root mean square errors can exceed 2.5 m and 1 m, respectively

    Geomorphology of four wave-dominated microtidal Mediterranean beach systems with Posidonia oceanica meadow: a case study of the Northern Sardinia coast

    Get PDF
    The results of this geomorphological study, which focuses on four Mediterranean embayed microtidal wave-dominated beach systems and the related inner shelf, are reported on a detailed geomorphological map (1:12,000 scale). The study area is located between Punta di Li Francesi and Lu Poltiddolu in NW Sardinia, W of the Strait of Bonifacio. The Main Map presents geomorphological, sedimentological, hydrodynamical and ecological (underwater vegetation) features indicated in nine sections of the map legend. Integrative maps (1:40,000 scale) of side-scan sonar surveys, sedimentary facies, survey routes and sampling point locations are also represented on the Main Map. This work summarizes 25 years of historical geomorphological datasets and can be considered as a reference for future comparisons of the study area as indicated by current European legislation. In addition to the scientific value of this study, the proposed map can be an important tool for coastal, beach and inner shelf management

    The use of genetic programming to develop a predictor of swash excursion on sandy beaches

    No full text
    We use genetic programming (GP), a type of machine learning (ML) approach, to predict the total and infragravity swash excursion using previously published data sets that have been used extensively in swash prediction studies. Three previously published works with a range of new conditions are added to this data set to extend the range of measured swash conditions. Using this newly compiled data set we demonstrate that a ML approach can reduce the prediction errors compared to well-established parameterizations and therefore it may improve coastal hazards assessment (e.g. coastal inundation). Predictors obtained using GP can also be physically sound and replicate the functionality and dependencies of previous published formulas. Overall, we show that ML techniques are capable of both improving predictability (compared to classical regression approaches) and providing physical insight into coastal processes

    Assessing the performance of an operational wave system within a Mediterranean beach monitoring programme

    No full text
    This work assesses the performance of an operational wave system in the Mediterranean Sea by comparing computed data with nearshore and deep water measured datasets. Nearshore data measurements were collected through a field experiment carried out at Poetto beach (Southern Sardinia, Italy) during April and May 2017. In addition to coastal observations, we use deep water wave data measured by a wave buoy in the Gulf of Lion. During the period of the experiment, an operational system including an atmospheric and a wave model ran once a day to predict the wave evolution out to 5 days in advance. We used a multi-grid approach in which a large grid extended over the entire Mediterranean basin and a fine grid covered the coastal seas surrounding the island of Sardinia. The comparison between simulations and measurements show that the operational wave system is able to satisfactorily reproduce the evolution of the significant wave height in deep waters where the relative error was 17%. The error exceeding 25% in coastal waters suggests that the use of a finer grid is advisable to accurately address nearshore wave transformation processes and wave generation driven by local meteorological forcing

    An operational wave system within the monitoring program of a Mediterranean beach

    No full text
    This work assesses the performance of an operational wave system in theMediterranean Sea by comparing computed data with measurements collected at different water depths. Nearshore data measurements were collected through a field experiment carried out at Poetto beach (Southern Sardinia, Italy) during spring 2017. In addition to coastal observations, we use intermediate and deep water wave data measured by two buoys: one situated North-West of Corsica and the other in the Gulf of Lion. The operational wave system runs once a day to predict the wave evolution up to five days in advance. We use a multi-grid approach in which a large grid extends over the entire Mediterranean basin and a fine grid covers the coastal seas surrounding the islands of Sardinia and Corsica. The comparison with measurements shows that the operational wave system is able to satisfactorily reproduce the wave evolution in deep and intermediate waters where the relative error of the significant wave height is 17%. The error exceeding 25% in coastal waters suggests that the use of a finer grid and the coupling with an atmospheric model able to catch local effects is advisable to accurately address nearshore wave processes driven by coastal wind forcing
    corecore