1,721,045 research outputs found
Evoluzione recente del sistema dunale di Lido di Dante-Foce Bevano (Ravenna): fattori naturali ed impatto antropico
No full textIl presente articolo descrive sei anni di monitoraggio della fascia dunale tra Lido di Dante e la Foce del torrente
Bevano, una delle poche aree naturali della costa dell’Emilia-Romagna. Il monitoraggio ha identificato uno
stato di degrado, ormai diventato irreversibile, di circa metà della fascia dunale, che tenderebbe a migrare verso
l’entroterra, attualmente occupata da una pineta costiera. I rilievi effettuati hanno identificato che, in seguito
alla progressiva riduzione dell’ampiezza della spiaggia a Sud delle opere di protezione di Lido di Dante, durante
le mareggiate si osserva il contatto tra l’azione del moto ondoso ed il fronte della duna. Il processo genera
una progressiva perdita di quota e la morte dell’ammofileto, esponendo quindi la duna stabilizzata all’azione
diretta delle onde e dello spray marino, in seguito all’obliterazione della duna mobile ad essa antistante. Sono
stati identificati due meccanismi di erosione della duna, in funzione della quota della cresta al di sopra del
l.m.m. e del volume in sezione: erosione del fronte della duna dovuta al crollo del lato esposto verso mare o
scavalcamento della cresta e progressiva formazione di morfologie “a collinetta”, che vengono erose lateralmente
fino alla loro obliterazione durante eventi di washover. Si pensa che l’indiscriminato accesso dei bagnanti alla
spiaggia attraverso i varchi presenti in punti dove il cordone è più basso sia un ulteriore fattore destabilizzante.
Nonostante siano stati tentati due ripascimenti della spiaggia (2005 e 2007), il volume di sabbia utilizzato non
è probabilmente stato sufficiente per dare respiro al sistema spiaggia-duna nelle zone più critiche, dove ad oggi
le dune sono ormai scomparse
A SIMPLIFIED METHODOLOGY FOR THE ESTIMATION OF WAVE RUNUP ON ARMOURED RUBBLE SLOPES FOR VULNERABILITY ASSESSMENT
No full textEvaluation of XBeach predictions for a real-time warning system in Emilia-Romagna, Northern Italy
No full textThe ability to predict coastal hazards several days in advance is a valuable tool for coastal managers to carry out necessary hazard-reduction measures. The project MICORE aims to develop an early-warning system of coastal hazards at nine distinct sites across Europe using a train of numerical models from the prediction of forcing parameters to the localized hydro/morphodynamics. A vital component of this project is the evaluation of morphology predictions of storm erosion, using the recently-developed XBeach model. In this study, XBeach predictions of two storms events on the Emilia-Romagna coastline in Northern Italy are assessed against measured beach response. This site is unique in that as well as consisting of relatively pristine natural areas, it also contains a series of offshore breakwaters protecting urban settlements and hence represents the first time XBeach has been run in such a setting. 1DH model runs at a natural section of the site predict the relatively minor dune erosion relatively well, with best results obtained by increasing the critical avalanching slope below water. For the section with offshore breakwaters, a 1DH model is found to be inappropriate due to the unreasonable increase in water levels modeled in lee of the structures. Water levels are observed to reduce significantly when running the model in 2DH, where return flow currents through the gaps in breakwaters are also included
Studio della variazione della linea di riva tramite l’analisi di immagini video e strumenti GIS
No full textCoastal Risk Assessment Framework tool for the identification of hotspots along the Emilia-Romagna coastline (northern Italy)
No full textThe Emilia-Romagna coastline is located in northern Italy, facing the Adriatic sea. The area is especially exposed to
the flooding hazard because of its low lying nature, high urbanisation and the large exploitation of beach resources
for tourism. The identification of hotspots where marine flooding can cause significant damages is, therefore, a key
issue.
The methodology implemented to identify hotspots is based on the Coastal Risk Assessment Framework tool that
was developed in the RISC-KIT project (www.risckit.eu). The tool combines the hazard component with different
exposure indicators and is applied along predefined coastal sectors of almost 1 Km alongshore length. The coastline
was divided into 106 sectors in which each component was analysed. The hazard part was evaluated through the
computation of maximum water levels, obtained as the sum of wave set-up, storm surge and tide, calculated along
representative beach profiles, one per sector, and for two return periods (10 and 100 years). The data for the
computation of the maximum water level were extracted from the literature. The landward extension of floodprone
areas in each sector was the extension of the flood maps produced by the regional authorities for the EU
Flood Directive and for the same return periods. The exposure indicators were evaluated taking into account the location and type of different assets in each sector and in flood-prone areas. Specifically, the assets that were taken into account are: the transport network, the utilities (water, gas and electricity) networks, the land use typologies, the social vulnerability status of the population and the business sector. Each component was then ranked from 1
to 5, considering a scale based on their computed value (hazard), importance and location (exposure indicators). A final coastal index (CI) was computed as the root mean square of the geometrical mean of the exposure indicators
multiplied by the hazard indicator. Land use typologies were valued taking into account a classification produced by the regional authorities for the Flood Directive. The social vulnerability status of the population was derived from data produced by the National Statistic Institute. The regional managers provided the location of transport and utilities networks. The business indicator was built considering the tourist arrivals in each coastal municipality
compared to the total number of arrivals. The results showed that the coast is very exposed to flooding and that the 100 year return period event leads to the identification of a large number of hotspots (65 over 106) defined as sectors with CI > 2.5. The main drivers for the hotspot identification were the hazard indicator and the land use typologies, because important transport/utilities network are not located in flood-prone areas. The most critical sectors are situated in the central-southern part of the coastline, where the most attractive tourist facilities are located and where the coastal corridor is occupied by a continuous urbanisation
Towards a pan-European coastal flood awareness system: Skill of extreme sea-level forecasts from the Copernicus Marine Service
Full text linkEuropean coasts are regularly exposed to severe storms that trigger extreme water-level conditions, leading to coastal flooding and erosion. Early Warning Systems (EWS) are important tools for the increased preparedness and response against coastal flood events, hence greatly reducing associated risks. With this objective, a proof-of-concept for a European Coastal Flood Awareness System (ECFAS) was developed in the framework of the H2020 ECFAS project, which capitalizes on the Copernicus products. In this context, this manuscript evaluates for the first time the capability of the current Copernicus Marine operational ocean models to forecast extreme coastal water levels and hence to feed coastal flood awareness applications at European scale. A methodology is developed to focus the assessment on storm-driven extreme sea level events (EEs) from tide-gauge records. For the detected EEs, the event peak representation is validated, and the impact of forecast lead time is evaluated. Results show satisfactory performance but a general underprediction of peak magnitudes of 10% for water levels and 18% for surges across the detected EEs. In average, the models are capable of independently flagging 76% of the observed EEs. Forecasts show limited lead time impact up to a 4-day lead time, demonstrating the suitability of the systems for early warning applications. Finally, by separating the surge and tidal contributions to the extremes, the potential sources of the prediction misfits are discussed and consequent recommendations for the evolution of the Copernicus Marine Service forecasting models towards coastal flooding applications are provided
Sediment transport pattern and coastal evolution at lido di dante beach, Adriatic Sea
No full textInter-disciplinary medium term monitoring of a small coastal cell of the Northern Adriatic, Lido di Dante Beach, was undertaken starting from 2001. In association with the EU-CoastView Project, coastal state indicators were developed and surveyed. This paper presents the observations done during 3 years of surveys: beach morphodynamics, intertidal bars, dune morphology and vegetation, overwash observation and risk. Results evidence two areas with different dynamics: the Southern part of the beach is dependent on the Bevano River by-pass processes and all indicators are positive (stable vegetation, large beach) while the Northern part is very narrow, eroding (10m/year) and the dune is easily overwashed. This atypical behavior is though to be due to the groin that disturbs the protective function of the nearshore bar system. Copyright ASCE 2006
Morphological thresholds for the definition of the vulnerability of coastal dunes in northern Italy
No full textEsame della fascia costiera Adriatica (settore italiano). Studio di dettaglio sulle aree che presentano le condizioni migliori per avviare lo studio avanzato sulla fattibilità del “sand engineering”. FASE 2
No full textConvenzione di ricerca tra Eni s.p.a. e il Dipartimento di Fisica e Scienze della Terra dell'Università di Ferrara (responsabile scientifico prof. Paolo Ciavola) - Le ben note problematiche legate ai processi di erosione costiera mantengono alta l’attenzione sulle aree litorali, spesso investite da fenomeni di arretramento della linea di riva. Molteplici sono gli interventi adottati per ridurne l’impatto negativo, ma non sempre l’esito è risultato essere quello atteso o, altrimenti, un mero palliativo. Per questo motivo ultimamente è stata concepita l’idea di realizzare sulla costa emiliano-romagnola un ripascimento artificiale caratterizzato da quantitativi di sabbia molto maggiori rispetto a quelli effettuati sinora, secondo caso in Europa dopo quello sulla costa olandese: il cosiddetto Sand Engine. Dopo un primo studio di fattibilità volto alla selezione dei siti idonei all’attuazione del progetto, il presente lavoro è finalizzato a produrre una piena caratterizzazione delle dinamiche sedimentarie e morfologiche dei due tratti di litorale scelti come potenziali Sand Motors, ovvero Lido di Spina – Bellocchio a nord e Lido di Dante – Lido di Classe a sud. Report finale
Run-up computation behind emerged breakwaters for marine storm risk assessment
No full textFlood vulnerability assessment due to marine storms is very important for integrated coastal zone management. The case study site is a highly developed area (Rimini) along the Emilia Romagna coastline, facing the north Adriatic sea in Italy. This area is composed of low sandy beaches and is completely protected by emerged breakwaters. Rimini was chosen in order to assess the vulnerability of a very important tourist resort that represents one of the most significant revenue for the regional economy. For the vulnerability assessment it was decided to consider the worst scenarios, using a joint probability of occurrence for a 1, 10 and 100 years return period storm, happening at the same time as an atmospheric surge and with the maximum spring tidal level of +0.45 m above MSL (run-up + surge + tide). The beach slope of different profiles was calculated using the a 2004-DTM (Lidar-based). The attenuation effect of the breakwaters was considered inside the run-up formula using the following method: (i) a 1-d model was used to evaluate the wave height at the seaward foot of each structure; (ii) the Van der Meer formula was applied to calculate the wave height behind structures; (iii) the calculated wave height was transported back to deep water conditions using a 1-d model. Different damage categories were created. The results reveal that, even with the one year event, most of the infrastructures are damaged and the areas behind the beach are flooded
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