Дисертації з теми "Littoral erosion"
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Chenault, Carla D. "Understanding long-term beach width change in the Oceanside littoral cell, California." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.
Niang-Diop, Isabelle. "Erosion côtière sur la petite côte du Sénégal à partir de l'exemple de Rufisque : passé, présent, futur." Angers, 1995. http://www.theses.fr/1995ANGE0003.
Pettit, Don Joseph. "Distribution of sand within selected littoral cells of the Pacific Northwest." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4311.
Rouiha, Abdellatif. "Formes et processus de corrosion littorale de calcaires crétacés au sud de El Jadida (Maroc)." Brest, 1986. http://www.theses.fr/1986BRES1005.
Following André Guilcher and Fernand Joly's study on corrosion forms in limestones along the atlantic coast of Morocco, our work concerns, with more detail, the region situated at the south of El Jadida, which is made of cretaceous, homometric, fine-grained limestones, and will thus allow a comparaison with coastal forms found in Morocco in other types of limestones. These corrosion forms show a vertical distribution with, in the upper part, very sharp lapies and intervening ponds and ovverhangs; in the midle part, very flat ponds with low, sinuous rims; and finally a low tide microclif. Such forms are not the result of the mechanicl action of the surf, but the result of boring by endolithic cyanophyceae and animals, action of lichen, and, on the other hand, of physico-chemical processus such as alternanations of wetting and drying, sea-water aggressivity, and corrosion by salt
El, Akhdar Mohammed. "Problèmes de la corrosion littorale de roches carbonatées en trois sites de la côte atlantique marocaine : (Dar Bou Azza, Jorf El Ihoudi et cap Tafelney)." Brest, 1986. http://www.theses.fr/1986BRES1004.
The present study is included in a more general framework dealing with the coastal corrosion forms in limestone in the world. So far as it is presently known, the processes are mainly biochemical, but they show different aspects under the diverse latitudes and must still be precised in order to have a differenciation in data, the sites in which the observation have been made are distributed over three places of the atlantic coast of Morocco : Dar Bou Azza, near Casablanca ; Jorf El Ihoudi near Safi and cape Tafelney in the great Atlas. Previous work by A. Guilcher and F. Joly had show the diversity of corrosion forms, but detailed studies still missed. The distribution of forms in altitude shows their vertical differenciation, and the biochemical processus and agents in bioerosion are especially detailed
Moufak, Fatiha. "Attaque littorale par corrosion de calcaires pléistocènes au sud-ouest de Rabat (Maroc)." Brest, 1986. http://www.theses.fr/1986BRES1003.
This essay continues with more precision the work carried on in 1954 by Guilcher and Joly on the Atlantic coast of Morocco. It concerns the sector at the south west of Rabat over a little more than twenty kilometers. This area consists of a coastal plain, with a littoral karst developed in pleistocene eolianites under the influence of a strong surf. The intertidal zone shows a rochy platform with steps separated by low, continuous rims. In the supralittoral, spray zone, very sharp lapies are found. Such forms do not derive from mechanical erosion, but from a conbination of biological and physico-chemical factors influenced by the climate. These coastal forms resemble very much those found in some intertropical and subtropical countries. Atlantic Morocco seems to be one of the countries where such featover are but developed
Hellsten, S. (Seppo). "Environmental factors and aquatic macrophytes in the littoral zone of regulated lakes:causes, consequences and possibilities to alleviate harmful effects." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514256719.
Tavares, Correa Carlos, and Fabian Drenkhan. "Shoreline Variation between Puerto Chicama and Puémape, La Libertad, Perú (1961-2006)." Pontificia Universidad Católica del Perú. Centro de Investigación en Geografía Aplicada, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/119293.
Mediante el empleo de material cartográfico y sistema de información geográfica (SIG), se realizó un análisis espacio-temporal, donde se comparó el comportamiento de la línea de litoral de un sector costero mínimamente afectado por la ocupación humana (Puémape–Puerto Chicama) con otros sectores costeros con ocupación moderada (La Chira–Lurín) a fuertemente modificada (Salaverry–Las Delicias y la bahía de Miraflores). Durante el período comprendido entre 1961 y 2006 para el sector Puémape–Puerto Chicama, se identificó el predominio del avance o estabilidad de la línea de costa. El sector La Chira–Lurín presentó un comportamiento similar, con tendencia a la estabilidad y los sectores fuertemente intervenidos presentaron un comportamiento netamente erosivo. Al contrario de lo esperado, la elevación del nivel del mar debido el calentamiento global no parece ser la causa principal de la erosión de playas en el Perú. Esta se debe principalmente a la fuerte intervención en costa ya que en sectores no alterados el predominio es de estabilidad o avance de la línea de litoral.
Jadidi, Mardkheh Amaneh. "Towards development of fuzzy spatial datacubes : fundamental concepts with example for multidimensional coastal erosion risk assessment and representation." Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25589.
Current Geospatial Business Intelligence (GeoBI) systems typically do not take into account the uncertainty related to vagueness and fuzziness of objects; they assume that the objects have well-defined and exact semantics, geometry, and temporality. Representation of fuzzy zones by polygons with well-defined boundaries is an example of such approximation. This thesis uses an application in Coastal Erosion Risk Analysis (CERA) to illustrate the problems. CERA polygons are created using aggregations of a set of spatial units defined by either the stakeholders’ interests or national census divisions. Despite spatiotemporal variation of the multiple criteria involved in estimating the extent of coastal erosion risk, each polygon typically has a unique value of risk attributed homogeneously across its spatial extent. In reality, risk value changes gradually within polygons and when going from one polygon to another. Therefore, the transition from one zone to another is not properly represented with crisp object models. The main objective of the present thesis is to develop a new approach combining GeoBI paradigm and fuzzy concept to consider the presence of the spatial uncertainty in the representation of risk zones. Ultimately, we assume this should improve coastal erosion risk assessment. To do so, a comprehensive GeoBI-based conceptual framework is developed with an application for Coastal Erosion Risk Assessment (CERA). Then, a fuzzy-based risk representation approach is developed to handle the inherent spatial uncertainty related to vagueness and fuzziness of objects. Fuzzy membership functions are defined by an expert-based vulnerability index. Instead of determining well-defined boundaries between risk zones, the proposed approach permits a smooth transition from one zone to another. The membership values of multiple indicators (e.g. slop and elevation of region under study, infrastructures, houses, hydrology network and so on) are then aggregated based on risk formula and Fuzzy IF-THEN rules to represent risk zones. Also, the key elements of a fuzzy spatial datacube are formally defined by combining fuzzy set theory and GeoBI paradigm. In this regard, some operators of fuzzy spatial aggregation are also formally defined. The main contribution of this study is combining fuzzy set theory and GeoBI. This makes spatial knowledge discovery more understandable with human reasoning and perception. Hence, an analytical conceptual framework was proposed based on GeoBI paradigm to develop a fuzzy spatial datacube within Spatial Online Analytical Processing (SOLAP) to assess coastal erosion risk. This necessitates developing a framework to design a conceptual model based on risk parameters, implementing fuzzy spatial objects in a spatial multi-dimensional database, and aggregating fuzzy spatial objects to deal with multi-scale representation of risk zones. To validate the proposed approach, it is applied to Perce region (Eastern Quebec, Canada) as a case study.
Montoya, Luis Humberto. "Analysis of a 10-year Nearshore Wave Database and its Implications to Littoral Processes." UNF Digital Commons, 2014. http://digitalcommons.unf.edu/etd/494.
Caillosse, Pierre. "La paroisse de Soulac de la fin du XVIe au milieu du XIXe siècle : les transformations d’un territoire littoral entre la Gironde et l’Atlantique." Thesis, La Rochelle, 2015. http://www.theses.fr/2015LAROF002/document.
Situated at the pointe du Medoc region, the parish of Soulac (modern day communes of Soulac-sur-Mer and Verdon-sur-Mer) is according to a medieval expression “at the end of the lands”. Squeezed between the Atlantic to the west, and the Gironde estuary to the east, the area includes a long coastline (14km of ocean coastline and 11km of estuary banks) which exposes it to phenomenon of natural origin linked to these maritime and fluvial-maritime movements. Since the end of the sixteenth century, the sand accumulated along the length of the coastline in the forms of dunes and carried by the wind onto habitations and cultures, causing the abandonment of the Soulac church and the early initial village in the mid eighteenth century. Simultaneously, the coastline was strongly attacked by erosion that spread in the middle of the Age of Enlightenment. To the east, the flat salt marshes were getting wider, reducing half their surface in less than a century. Finally, the low-lying areas of the parish are exposed to marine submersions, despite beginning with little frequency. This micro space, of 50km2, encompasses a good observation point in order to study the transformations of coastal land and the adaptations of populations to these changes. Taking support from important documentary resources (textual archives and cartographic maps) and continuous in the time (from the end of the 16th century to the middle of the 19th century), the analysis combines traditional historic methods with the possibilities offered by the contemporary computer tools, such as GIS (geolocation, extraction of qualitative data and quantitative old maps). The spatiotemporal analysis allows for the geohistoric reconstruction of the Soulac landscape over a long period, reflecting the natural dynamics, the important transformations and the responses from the inhabitants. The inhabitants, firstly made powerless by the authorities and had given up on themselves, have adapted to the changes by adopting many strategies throughout the course of the 18th century. From the simple control of the sand, using boundaries that dry up the soft, dirty marshes, they are trying to respond to the constraints forced upon them by their environment. However, the actions of the government at the beginning of the nineteenth century which allow for the success of the preventative actions and the start of a new era. The dunes fixed by pine trees and the erosion, stopped by the construction of structures, has given birth to the current landscape at the point of Medoc. More than a simple parish monograph, this case study allows us to ask questions about our environment and the affect that the interactions of cultivation and people have. Reconstructing over a long period of time the transformations offers a better understanding of the risks and the phases of construction of a geographical area offering a historical reviews which allows for a better understanding recent events
Bujan, Nans. "Application d'un modèle de circulation quasi-tridimensionnel littoral à la dynamique des plages du Languedoc-Roussillon." Phd thesis, Montpellier 2, 2009. http://tel.archives-ouvertes.fr/tel-00438713.
Crapoulet, Adrien. "Évolution du trait de côte, bilans sédimentaires et évaluation des zones à risques sur le littoral du Nord-Pas-de-Calais : analyse multi-échelles par LiDAR aéroporté." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0383/document.
Sandy beaches and coastal dunes still represent a significant portion of the coastal of Nord-Pas-de-Calais, northern France. These sandy accumulation landforms, which sometimes constitute the only defense protecting low-lying coastal areas from coastal flooding, are particularly vulnerable to sea level rise associated with climate change. The main objectives of the thesis were to analyze shoreline change and coastal sediment budget at the regional scale, to assess the role of changes in sediment volume on shoreline stability,and to evaluate areas at risk from coastal hazards in the near future, using airborne topographic LiDAR data collected between 2008 and 2014 and aerial photographs from 1963 to 2009. Analyses of shoreline change revealed spatially as well as temporally variables evolutions.Seaward shoreline progradation occured along several stretches of coastline at multidecadal and short times-scales, while significant coastal retreat took place at other sites during the same time periods. The comparison between coastline evolution and the initial volume of the upper beach in 2008 showed that the higher retreat rates were mainly observed in areas where the upper beach was lacking at high tide. Our results also suggest that there is a sediment volume threshold on the upper beach at each site above which the coastline is stable or progrades seaward. Mapping of areas at risk of marine flooding in 2050, taking into account a projection of sea level rise due to climate change, clearly shows that the submersion of coastal dunes would take place at several sites during storm-induced high water level events. The mapping of these areas at risk being based on topographic data collected in December 2013 and January 2014, coastal flooding is very likely to occur much earlier than 2050 at several sites, however, where very high rates of coastal retreat result in severe erosion of the coastal dunes. The calculation of sediment budget based on the repetitive LiDAR surveys shows that, overall, sediment accretion predominates over the entire regional coastal zone. This accretion is particularly significant for the upper beach and coastal dunes, except for a few sites that are characterized by a strong sediment deficit (particularly Wissant bay and the Northern shore of the Authie estuary). These results suggest that the coastal zone of Northern France does not experience sediment shortage, but is rather dominated by sediment storage in the backshore of the sand beaches
Borie, Mariane. "Les massifs rocheux crétacés supérieurs du Labourd occidental : processus d'altération et instabilités littorales." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13732/document.
This work is an analysis of the consequences of the presence of weathered rocks, called alterites, on the coastal landslides of the Labourd (Basque country). The environmental context (geological, hydrogeological and morphological) of the landslides is studied to a better understanding of the failure processes. These studies allow to highlight the main triggering factors of the landslides, which are validated by numerical modelling. The knowledge of the processes so improved, a tool to estimate landslide hazards in the alterites is proposed
Bawedin, Vincent. "La Gestion Intégrée des Zones Côtières (GIZC) confrontée aux dynamiques territoriales dans le bassin d'Arcachon et sur la côte picarde." Phd thesis, Université de Nantes, 2009. http://tel.archives-ouvertes.fr/tel-00431534.
Hugo, Pierre-Malan. "The impact of climate change effects on the planform of a headland-bay beach on the southern coast of South Africa." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79917.
ENGLISH ABSTRACT: The various consequences of climate change pose a significant threat to developments near the coast. These threats include saltwater intrusion, coastal erosion and flooding. In the coastal context, the climate change effect often raising the most concern is that of sea-level rise. Much work has therefore been done on the linear setback caused by a rise in sea-level. In order to get the full picture of possible changes caused by sea-level rise, the secondary effects of a rising sea-level also need to be considered. Sea-level rise could cause changes to the nearshore wave climate and could have impacts such as coastal erosion and changes to the coastline shape. The primary objective of this study was therefore to investigate the effects of sea-level rise on the nearshore wave climate and, consequently, the coastline stability. Other consequences of climate change considered in this study include increasing average wave heights and a rotation of offshore wave directions. The many headland-bay beaches on the South African coastline are generally in a state of dynamic equilibrium and find their planforms based on the local wave climate. Changes to the wave climate may therefore disrupt the equilibrium shapes of these bays. This study was therefore also aimed at investigating the effects of the changes to the wave climate on the stability of headland-bay beaches. The three consequences of climate change expected to affect the nearshore wave climate were identified as (1) sea-level rise; (2) an increased wave height; and (3) changing offshore wave angles. Although changes to storm frequency and intensity are also possible, the impacts of these changes were not studied. In order to assess the impacts of the three considered changes on a typical headland-bay beach, two numerical models were set up for Mossel Bay – a headland-bay beach on the southern coast of South Africa. The modelling approach included a wave transformation model to calculate nearshore wave climates from offshore data and a coastline model to assess the stability of the bay under the changed nearshore wave climates. The model results indicated that the rising sea-level alone would cause changes in the nearshore wave direction. These changes were shown to alter the longshore sediment transport regime such that rotations are expected in the south-western corner and eastern end of Mossel Bay. These rotations do not include the cross-shore effects of inundation and erosion, as suggested by models such as the Bruun Model. The results for an increased offshore wave height were inconclusive. The southerly rotation in offshore wave angles was shown to affect the nearshore wave angles. These changes affected the longshore transport regime such that the outward sediment transports were reduced. A minor accretion resulted in the centre of the bay for a 1° southerly rotation in offshore wave angles. For a 2° rotation, the extent of accretion increased and shifted towards the eastern end of the bay, primarily due to the dominance of south-westerly waves in the local wave climate. A valuable observation was made regarding the current stability of Mossel Bay. Inter-tidal reefs are present along three sections of the bay. These reefs protect the coastline such that the current bay shape contains sharp bends between the reefs. Under a rising sea-level, however, the effect of the reefs will become less pronounced. If a water level should be reached where these reefs become less significant, the planform of the bay is expected to smooth out through a significant redistribution of sediment. This smoothing effect was shown to cause erosion of the coastline in the order of 80m near the town of Klein Brak River.
AFRIKAANSE OPSOMMING: Die verskeie gevolge van klimaatsverandering bied ‘n merkwaardige bedreiging vir ontwikkelings naby die kus. Hierdie bedreigings sluit die versouting van varswaterbronne, kuserosie en oorstromings in. Vir kusgebiede is seevlakstyging gereeld die effek van klimaatsverandering wat die meeste kommer wek. Dus is heelwat navorsing rakende die direkte erosie as gevolg van seevlakstyging reeds gedoen. Om die volle beeld van die gevolge van ‘n stygende seevlak te verkry, is dit egter nodig om ook die sekondêre effekte hiervan in ag te neem. Seevlakstyging kan veranderinge in die golfklimaat naby die kus veroorsaak, en kan impakte soos kuserosie en veranderende baaivorms tot gevolg hê. Die primêre doel van hierdie studie is dus om die effek van seevlakstyging op die golfklimaat by die kus en gevolglik die stabiliteit van die kuslyn, te ondersoek. Benewens die styging van die seevlak word die effekte van groter gemiddelde golfhoogtes en die rotasie van diepsee golfrigtings ook in hierdie studie ondersoek. Die vele landpunt-baaie (headlandbay beaches) op die Suid-Afrikaanse kus is meestal in ‘n dinamiese ekwilibriumtoestand, waarvan die vorm deur die lokale golfklimaat bepaal word. Veranderinge aan dié golfklimaat mag dus die ekwilibrium vorms van sulke baaie versteur. Hierdie studie het dus ook die stabilititeit van landpuntbaaie onder ‘n veranderende golfklimaat ondersoek. Die drie gevolge van klimaatsverandering wat verwag word om die golfklimaat naby die kus te beïnvloed is geïdentifiseer as (1) seevlakstyging; (2) vergrote golfhoogtes; en (3) veranderende diepsee golfhoeke. Veranderinge aan die frekwensie en intensiteit van storms is ook moontlike gevolge van klimaatsverandering, maar die impakte hiervan is nie in die studie ondersoek nie. Twee numeriese modelle is toegepas om die impak van die drie bogenoemde gevolge op Mosselbaai – ‘n tipiese landpunt-baai aan die suidkus van Suid-Afrika – te ondersoek. ‘n Golfmodel is ingespan om die golfklimaat naby die kus te bepaal waarna ‘n kuslynmodel gebruik is om die stabiliteit van die baai onder die veranderde golfklimaat te ondersoek. Die resultate van die studie dui daarop dat die golfhoeke naby die kus beïnvloed word deur seevlakstyging. Daar is aangetoon dat dié veranderinge die langsstroomvervoer sodanig sal verander dat kuslynrotasies in die suid-westelike hoek asook die oostelike rand van Mosselbaai verwag word. Hierdie rotasies sluit nie die lineêre landwaartse verplasing van die kuslyn as gevolg van erosie en oorstroming in nie. Die effek van vergrote golfhoogtes kon nie met akkuraatheid ondersoek word nie. Daar is wel gevind dat die suidwaartse rotasie van diepsee golfhoeke rotasies in die golfklimaat naby die kus veroorsaak. Hierdie rotasies verander die langsstroom sedimentvervoer sodanig dat die uitwaartse sedimentvervoer verminder word en ‘n klein opbou van sediment in die middel van die baai vir ‘n 1° diepsee rotasie verwag word. Vir ‘n 2° suidwaartse rotasie is daar ‘n groter opbou van sediment wat verder ooswaarts veplaas is. Die ooswaartse veplasing is primêr ‘n gevolg van die oorheersing van suid-westelike golftoestande in die golfklimaat. ‘n Waardevolle gevolgtrekking rakende die huidige stabiliteit van Mosselbaai is ook gemaak. Langs drie gedeeltes van die Mosselbaaise kus word riwwe in die gebied tussen hoog- en laagwater aangetref. Hierdie riwwe beskerm die kus sodanig dat skerp kinkels in die vorm van die baai tussen die riwwe gesien kan word. Wanneer die seevlak styg, word die beskermende effek van die riwwe egter minder doeltreffend. Indien ‘n watervlak bereik word waar dié effek genoegsaam verminder is, word daar verwag dat die baai deur ‘n merkwaardige verplasing van sediment die kinkels sal uitstryk. Deur hierdie proses word erosie in die orde van 80m naby die dorp van Klein Brakrivier verwag.
Herbette, Steven. "Erosion des tourbillons océaniques : influence de la topographie et d'un front isopycnal : Application aux Anneaux des Aiguilles." Brest, 2003. http://www.theses.fr/2003BRES2006.
Both satellite observations and measurements at sea show that the characteristics of the Agulhas Rings are strongly modified while they propagate north-westward across the Cape Basin, in the South Atlantic. Some get eroded by topography as they encounter seamounts ridges. Others may be cooled down by strong air/sea exchanges in austral winter at high latitudes and then subduct further north as they encounter lighter waters. We here study two processes of rings erosion, one related to topography, the other related to subduction under an outcropping isopycnal front. Our study is based on idealised numerical experiments with an isopycnal coordinate model, MICOM. We first initialize a stable vortex in the surface layers by carefully choosing its potential vorticity anomaly (PVA) profile. We then consider adiabatic erosion mechanisms for which the PVA is a lagrangian tracer. Thus, the latter is used in our experiments to quantify the erosion. We use the Okubo-Weiss quantity to show to that adiabatic erosion is always due to the lost of filaments of potential vorticity (PV) and is therefore a kinematic process. While the vortex encounters an isolated seamount, we show that erosion is induced by topographic vortices that form near the topography in the bottom layers and that generate strong strain effects in the surface adjacent layers. While subducting under an outcropping front, two main mechanisms cause the erosion of the vortex core. The first one is induced by the velocity shear associated with the front. The second mechanism occurs once the vortex has subducted. Entrainment of high PV fluid parcels from the front above the vortex low PV core modifies the stability properties of the latter. Meanders are observed to grow at the rim of the structure, which favours the expel of PV filaments
Quinquis, Michel. "Relations entre bassins versants et cellules sédimentaires littorales : les exemples du Maroc, de l'Algérie et de la Tunisie." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0330/document.
In this study conducted on the Mediterranean coast of Morocco, Algeria, and Tunisia at an extended spatial and temporal scale (2200 km of coastline and about 100 years), we determine, using a "source-to- sink ", the existing relationships between erosion produced in watersheds and sediment transported in suspension by wadis, with the redistribution of these sediments along the shoreline. We propose a new empirical model of suspended sediment transport along the watersheds of our study site. We then determine the impact of dams on the sediments, and then quantitatively estimate the sedimentary contributions to the sea. We analyze the morphological characteristics of the littoral according to its geometry and the morphodynamic indices from the literature . After mapping the position of the coastline at different periods, the kinematics of the shoreline is determined, as well as the shoreline drift. These analyzes are based on the concept of a littoral cell. We conclude with a general synthesis before drawing the main conclusions on the relations between watersheds and coastal cells, such as (1) the role of precursor and sediment buffer played by deltas to limit the erosion of beaches in the sector (3) the links between sediment inputs from pre-barrage wadis, minus the volume of sediment moved by the coastal drift, with the size of the deltas and the number of coastal bars
Calvet, Fabrice. "L'appréhension juridique du risque d'érosion côtière." Thesis, Perpignan, 2014. http://www.theses.fr/2014PERP1194.
The aim of this study is to analyze how the risk of coastal erosion is apprehended at a legal point of view. This natural risk is characterized by a gradual encroachment of the sea on land, intending to grow in the coming decades according to the latest scientific reports. However, it is observed that beside this, the metropolitan coast are home to an increasingly growing population ; so we find the meeting of two contradictory trends. Therefore, the purpose of this study is to observe the legal consequences of this confrontation. So, in order to achieve the reconciliation of these issues, we will demonstrate the importance of the development of public policies for managing coastal erosion in favor of an integrated approach, based on fundamental principles of ICZM. Our study will thus provide a legal expression of this development
Basara, Noémie. "L'érosion des littoraux à falaises meubles en Bretagne : aléa, enjeux et gestion du risque." Thesis, Brest, 2019. http://www.theses.fr/2019BRES0066.
The erosion of soft cliffs results from the denudation of inherited, superficial formations covering the current coastlines. Their retreat rate is unsteady and often smaller than on accumulation coasts. This type of cliffs represents, in Brittany, 20 % of the coastline. Although their evolution is not fully understood, urbanization and human activities have grown denser at the top of these soft cliffs and behind, in recent decades. This thesis addresses coastal erosion with a focus on coastal risks induced by current urbanization of these soft cliffs at regional scale. The analysis tackles the hazard, stakes and management components in order to assess erosion risk and to draw near the vulnerability of these territories.A systemic approach is adopted, nesting temporal and spatial scales, with the objective to identify the components contributing to the vulnerability of these coastal territories.A chronicle of erosion events at regional scale is produced to present the spatio-temporal distribution of erosion over the 20th and 21st centuries and to analyze the generating factors.Focusing on six representative sites, aerial photographs (between 1950 and 2015) and photogrammetric monitoring (from 2017 to 2019) allow a quantitative study of the kinematics of soft cliffs retreat. A new paradigm for assessing and mapping the erosion risk for soft cliffs is proposed.Finally, indicators for stakes and risk management allow assessing vulnerability at these sites, and a survey conducted among regional stakeholders identifies gaps in risk management policies. According to their type, soft cliffs show a range of erosion responses, controlled by a combination of subaerial and marine factors, including rainfall. In Brittany, their retreat threatens mainly residential and agricultural lands. The vulnerability indicators highlight the paucity of regulations, local management strategies, dialogue and public awareness. They allow a better understanding of the challenges raised by risk erosion management
Sinane, Kamardine Mohamed. "Les littoraux des Comores, dynamique d'un système anthropisé : le cas de l'île d'Anjouan." Thesis, La Réunion, 2013. http://www.theses.fr/2013LARE0027/document.
In the context of climate change and sea level rising, the activities of coastal communities can increase the vulnerability of the seashore to coastal erosion particularly in small developing islands as Anjouan in the Comoros archipelago where the human density on the coast is quite heavy. This thesis focuses on sandy beaches, studied as a system. The monitoring of topographic profiles of beaches and landscaped geoindicators show that a large part of the sandy coast of Anjouan is very degraded and eroded. The erosion is mainly localized to areas of high human pressure, including beaches subjected to the extraction of sediments . Combined with natural hazards, the erosion due to human activities generates serious damages for the economy, society and environment of Anjouan, including the degradation of ecosystem services on which the government could draw to initiate the development of the island . To reduce the vulnerability of the coastline to erosion, walls are built with the financial support of international and regional bodies, but they are inefficient and the risk of coastal degradation is even greater. For beach users, causes erosion are to be found in the work of the man and not in nature. Minimizing this risk requires socio-economic measures to reduce anthropogenic degradations. This study shows that a policy of ICZM in Anjouan in the Comoros and elsewhere will only be effective if those responsible for its implementation take into account local realities and perceptions of coastal users
Lequien, A. "DYNAMIQUE EROSIVE ACTUELLE ET TRANSFERTS FLUVIATILES DANS L'OUEST DU BASSIN DE PARIS. Exemple de bassins versants littoraux en Haute Normandie : le Dun, la Ganzeville et l'Yères." Phd thesis, Université de Rouen, 2006. http://tel.archives-ouvertes.fr/tel-00919196.
Vanhuysse, Charles. "Impacts de l'ostréiculture à mésoéchelle sur le microphytobenthos et ses performances photosynthétiques, la macrofaune benthique et rôle de l'érosion estuarienne dans les mortalités de naissains d'huitres Crassostrea gigas liées à OsHV-1 μ Var Drivers of epipelic mictophytobenthic photobiology and groth in oyster farm Benthic macrofaunal changes in oyster parks during an OsHV-1 µVar oyster spat mortality outbreak Environmental dynamics of the Ostreid herpes virus (OsHV-1 µVar) in oyster spats and microphytobenthic biofilms during an in situ mortality outbreak In situ resuspension of benthic sediments and biofilm components during an OsHV-1 µVar Crassostrea gigas oyster spat mortality episode". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC262.
Since 2008, the mortality of Pacific oyster spat Crassostrea gigas has mainly been linked to the Ostreid herpesvirus 1 μvariant (OsHV-1 μVar). Environmental parameters favoring the persistence and spread of the virus could affect its propagation dynamics. The objectives of this thesis were to study in situ the interactions between oyster spat and their benthic environment during an episode of mortality. The photobiology of the microphytobenthos beneath the tables seemed to be in a better state compared to that observed in aisles that could promote viral resilience. The oyster tables attenuated light, temperature and desiccation, thus avoiding thermo and photoinhibition of the microphytobenthos. The benthic habitat environmental quality indices based on the macrozoobenthic community showed a degradation of the environment following the influx of organic matter induced by oyster spat mortalities and strandings of the macroalgae. A significant amount of OsHV-1 was found on the surface of the biofilm before the mortalities. Resuspension was preferentially associated with microphytobenthic particles with small currents
Duguet, Timothée. "Le recul des falaises de craie de Normandie à l’échelle du Quaternaire, par approche terre-mer." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMLH29.
The chalky cliff coastline of Normandy is characterized by a vertical cliff at the foot of which develops an intertidal coastal platform, which is subject to strong erosion, illustrated by the rapid retreat of its cliffs. This thesis deals with the qualification of the '' short-term (annual) and long-term (multi-millennium) erosion of the Normandy chalk cliffs by the use of various methodologies: 1) A first quantitative approach by photogrammetry was carried out on the Senneville-sur Fécamp cliff with the aim of quantify the erosion of the cliff face over a period of one and a half years, and identify the main factors responsible for this erosion. 2) The acquisition of bathymetric data in coastal areas has made it possible to identify specific morphologies of rocky platforms underwater, indicative of the past erosive dynamics of the cliffs. 3) A morphometric analysis by numerical method of worm basins sants de Seine-Maritime was built on the hanging valleys of the chalky coast. It made it possible to locate the cliff paleo-position on the eroded platform by projection of the slope profile. Thus, long-term recoil speeds of the coast have been extended to the whole of the Seine-Maritime coast. 4) Cosmogenic dating using the 10Be isotope was carried out on flint relics of the stripped platform made it possible to validate the rates erosion determined over the period of several millennia
Mineo-Kleiner, Lucile. "L'option de la relocalisation des activités et des biens face aux risques côtiers : stratégies et enjeux territoriaux en France et au Québec." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0042/document.
Since 2012, the French government has carried out a national strategy for the integrated coastline management that promotes managed retreat (or relocation) included in a territorial project. In Quebec, such a strategy has not been developed, but houses are occasionally displaced or destroyed. This PhD focuses on how managed retreat is tackled in France and in Quebec. A first assessment of past experiences reveals that relocation has rarely been materialized as the French government conceives it. The aim of this research is to confront the ideas supported by governments through their public policy with the ground and to identify the obstacles and the possibilities of implementing relocation. To reach this goal, we have gathered the opinion of institutional stakeholders through semi-directive interviews. Two polls have also been carried out to get inhabitants point of view. These surveys reveal dissimilarities in the approaches taken by governments and institutional actors in France and Quebec. It reflects fundamental differences in public policy in both territories. Moreover, the implementation of relocation raises many common issues, financial, land management and social acceptability issues. Major constraints concern governance of relocation project, which is based on an unpopular idea and is a long term challenge. Interests at different scales seem to be sufficiently antagonistic to compromise the emergence of a territorial project integrating relocation. Nevertheless, a law proposal in France and a recent evolution of the Quebec government's action open up new perspectives
Blaise, Emmanuel. "Etude des dynamiques du trait de côte de la région Bretagne à différentes échelles spatio-temporelles." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0010/document.
This research is part of current context of increasing of human beings and human activities vulnerability face to coastal risks (erosion hazards and marine submersion), linked to global environmental changes (global relative sea level rise and growth of storms’ frequency and intensity) and the current concentration of the population on the coastline. Following the storm Xynthia (February 2010), France has adopted a national strategy dealing with coastal erosion and shoreline retreat, in order to define a new integrated national strategy of coastline management, promoting the relocation of stakes and properties. This strategy focuses on the monitoring of shoreline changes and the identification of coastal risks due to erosion.This work fall within this issue. The main objective was to study sedimentary coasts dynamics (sand dunes and gravel barriers) of Brittany, following different spatial and temporal scales. In the long term, the analysis consisted, first of all, in establishing a typology of sedimentary coasts according to several morpho-sedimentary criteria; then, coastline kinematic has been analyzed over the last sixty years (1950-2010) through a diachronic study using photogrammetry. In the medium term, analysis was carried out as part of topographic surveys performed at multi-annual to multi-decadal scale, on several Observatoire du Domaine Côtier (IUEM) and/or Service National d’Observation - Dynalitt survey sites. The morpho-sedimentary study was combined with a wave, tide, wind and atmospheric pressure analysis, in order to explain the role of these forcing in the erosion and recovery successive phases. Finally, in the short term, analysis was based on high frequency of topomorphological surveys carried out during the 2013-2014 stormy winter. Additionally, an experimental study to quantify runup process, in order to analyze extreme water levels impact on shoreline erosion.Overall, the quantification of coastline variations over the long term revealed an erosion tendency on 27% of the studied linear, a non-negligible progression of the shoreline on 20.5% of the studied linear, and a significant shoreline anthropogenic impact (34.5% of the studied linear). The similarity of the morpho-sedimentary responses of the littoral strands studied to the meteorological conditions allowed to identify five distinct phases. Three morphogenetic phases (1998 to 2003; winter 2006/07 to spring 2008; winter 2012/13 to the present), characterized by severe shoreline erosion combined with a high frequency of storm episodes, and two phases (2003 to winter 2006/07 ; spring 2008 to winter 2012/13) characterized by milder weather conditions, allowing shoreline recovery. During 2013-2014 winter, three storms were particularly morphogenetic for sedimentary coasts, because they were combined with high spring tides: January 4-5, February 1-3, and March 2-3. During this winter, the average retreat for all studied sites reached -6,3 m, with a maximum of -30,1 m and a minimum of -0,2 m
Capanni, Romain. "Étude et gestion intégrée des transferts sédimentaires dans le système Gapeau/rade d'Hyères." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10187/document.
The Var beaches have been gradually reduced during the second half of the twentieth century and they survive mostly thanks to costly artificial recharge. In this context, the response of the environment and the risk intensity depend primarily on the sedimentary support provided by the coastal rivers. This study looks to quantify the role of sediments transported by the Gapeau with particular reference to its mouth and neighbouring beaches during flood and storm events. We study the solid load measured in the river, theoretical transport equations in the literature and the evolution of the channel and Hyeres’s coastal bathymetry during the last century and during events. These analyses reveal important retraction and erosion that has impacted upon the area since 1896 and the current low sediment supply. The estimated average annual sediment losses along the coast are higher than the average annual river sediment supply
Brunier, Guillaume. "Côtes sablo-vaseuses sous influence deltaïque de l'Amazone et du Mékong : dynamique morpho-sédimentaire, stabilité et aménagement." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM3112.
This thesis is a geomorphic study of two separate sites associated with two large deltas: the Amazon and the Mekong, with a focus on a beach and chenier in French Guiana integrated into the mud dispersal system of the Amazon, and on the links between destabilization of the Mekong delta shoreline and morpho-bathymetric changes in the deltaic channels under increasing human influence.The study of Montjoly beach in French Guiana was carried out using a combination of an innovative approach in SfM (Structure from Motion) airborne photogrammetry, hydrodynamic and bathymetric measurements, and wave propagation modelling over the nearshore bathymetry. The results show the strong potential of SfM photogrammetry in high-resolution morphometric and sediment budget surveys of sandy beach, and confirm a previously proposed model of beach rotation under mud-bank influence.The second field site in French Guiana, a retreating chenier over a muddy abandoned polder formerly a rice fields, work based on a multi-decadal analysis of satellite images combined with short-term field topographic and hydrodynamic measurements highlighted high rates of chenier migration (up to 160 m a year) and retreat mechanisms over the muddy substrate due to its rheology.A GIS-based analysis of bathymetric changes in the deltaic channels of the Mekong over a 10-year period (1998 to 2008) enabled the quantification of a net loss of 200 million m3 of sediments and an increase in the mean depth of the channels, which appears as unnatural and due to sand mining.These important sediment extractions have serious repercussions on sediment supply to the Mekong delta coast, which shows important rates of erosion
Than, Van Van. "Modélisation d'érosion côtière : application à la partie Ouest du tombolo de Giens." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4736/document.
The objective of this thesis is the determination of the causes of sea erosion phenomenon, and the production of policy proposals for the protection of the beach. The study begins with the collection and analysis of all available data, to find evolution rules of tombolo of Giens. Which aims to explain how the hydrodynamic processes and sediment transport occur. Then MIKE modeling software was applied to confirm the hypothesis and get a better understanding of the dynamics at work in the Western tombolo. Then, we coupled factors simultaneously: waves, coastal currents and sediment transport for different regimes of wave and wind in MIKE 21. Finally, the possibility of stabilizing the Western tombolo is discussed to give suggestions on the choice of solutions
Huteau, Charlotte. "Le déplacement en zones côtières : entre anticipation et gestion des risques naturels : perspectives juridiques." Thesis, La Rochelle, 2016. http://www.theses.fr/2016LAROD002/document.
Coastal areas have always been attractive for their economic potential and their touristic and residential interest. They have been massively settled in countries all over the world. However, while coastlines are weakened by human impact, they are also subject to degradations due to climate change. Besides the sea-level rise, often emphasized by the media, we must consider the erosion caused by storms and hurricanes. The current context is strongly marked by the question of the environmental displaced persons who do not have any status. This situation can be illustrated by the small island states whose territory is threatened by the sea-level rise. Thus, the issue of managing these problems in respect with human rights arises to an increased extent. The challenge of this work, supported by different country profiles: Bangladesh, USA, France, Small Island States (including the Maldives, Kiribati, Tuvalu), is to seek the root causes of this dilemma that has become so intense that it leads to displacement, and then to promote and facilitate adaptation in-situ or adopt new displacement policies that are no longer perceived as a failure but as an adaptation strategy towards risks. This change of perspective intends to mobilize legal tools from various branches of law (Urbanism, Insurance, Liability and humanitarian law, etc.). It also intends to respect principles to ensure anticipation and acceptance of the approach by the people. With the study of these examples, we must identify these commons elements and take into account the specificities of each country and each community
KROLOVÁ, Monika. "Factors affecting the occurrence of littoral vegetation in a reservoir with storage function." Doctoral thesis, 2013. http://www.nusl.cz/ntk/nusl-155310.
Trindade, Jorge. "Dinâmica morfossedimentar de praias dominadas por sistemas de arriba : (Peniche - Cascais)." Doctoral thesis, 2010. http://hdl.handle.net/10400.2/1733.
A presente tese tem como objectivos principais a caracterização da morfodinâmica de praias e a determinação de áreas susceptíveis à erosão e à inundação marinhas em sistemas litorais arenosos da Estremadura, entre Peniche e Cascais. As praias estudadas são o sistema compósito praia-duna/praia-arriba da praia de Sta. Rita, o sistema praia-duna da praia Azul e o sistema praia-duna da praia da Foz do Lizandro. Pretende-se estudar a dinâmica planimétrica e das propriedades geométricas e volumétricas dos perfis de praia face à actuação dos vários agentes envolvidos nas modificações morfológicas, determinando os seus limites de variação e prevendo do seu comportamento morfodinâmico sob condições distintas das que ocorreram durante o estudo. Tendo em conta os resultados obtidos, avalia-se a susceptibilidade dos sistemas de praia à inundação e à erosão através do estudo dos factores associados à perigosidade e à modelação empírica de perfis de praia. O estudo baseia-se na aquisição sistemática de dados morfológicos através da realização de perfis transversais na praia emersa, utilizando técnicas topográficas localmente validadas. A par dos dados morfológicos são recolhidas amostras sedimentares dos elementos mais dinâmicos do perfil de praia para caracterização sedimentológica. A monitorização das praias forma a base, juntamente com dados da ondulação de largo e das marés previstas e medidas, para a avaliação do comportamento dos sistemas através de tratamento estatístico ou da aplicação de modelos matemáticos de previsão. No quadro da caracterização dos factores envolvidos na dinâmica das praias são caracterizadas as marés e a agitação marítima junto à área de estudo, recorrendo, no último caso, às séries antigas de ondulação de Peniche e de Cascais. Estas séries correspondem ainda à base para a previsão de valores extremos de ondas na área de estudo. Juntamente, são determinadas as características das ondas e dos temporais no período de referência do estudo, utilizando as séries actuais de Leixões e de Sines. São determinados os principais indicadores da dinâmica do sector emerso das praias bem como a previsão do comportamento morfodinâmico das praias. Incluem-se neste lote de análise a dinâmica planimétrica, as modificações morfométricas traduzidas nas variações verticais máximas dos perfis de praia, da altitude da berma e do declive da face da praia, o balanço volumétrico e as modificações texturais dos sedimentos dos sistemas estudados. A avaliação da susceptibilidade das praias estudadas à inundação e erosão marinhas é determinada através do cálculo de indicadores que permitem a cartografia da incidência e das consequências da ocorrência de fenómenos extremos no litoral estudado.
The aim of this thesis is to characterize beach morphodynamics and to define inundation and erosion susceptibility areas within the sandy coastal systems of the Estremadura, between Peniche and Cascais. The study sites are the composite beach – dune / beach – cliff system of the Sta. Rita beach, the beach – dune system of the Azul beach and the beach – dune system of the Foz do Lizandro beach. The planimetric dynamics of the beach and the geometrical properties of the beach profiles as well as the volumetric variability are studied as a product of the geomorphological agents dynamics. Inundation and erosion susceptibility assessment is then preformed through the analysis of the main hazard variables and with the empirical modeling of the beach profiles. Systematic beach profiling is used as the main methodology to acquire morphological change data from the beach system. Topographical techniques are applied and locally validated. Data from sediment sampling over the most dynamic sectors of the beach profile is also a part of the basic field information for this study. The field data together with offshore wave data and tide measurements are the basic information for the characterization and prediction of the beach systems behavior through statistics and mathematical modeling. Tides and waves are analyzed using data series of the nearby tide gauges and wave buoys, including the older wave time series of Peniche and Cascais collected in the 80’s. This data is used to calculate and predict extreme wave values in the study area. Present day offshore wave data from Leixões and Sines wave buoys is the basis for hydrodynamic characterization during the study period, including mean and storm conditions. The main morphodynamic indicators and predicted behavior are calculated for the emerged beach profiles including planimetric dynamics, maximum vertical and berm altitude variability, beach profile modifications through time, profile volumetric budget and sediment textural changes in time and space. The marine inundation and erosion susceptibility assessment is based on indexes composed of simple variables and mathematical modeling of the beach profiles. These indexes are basis for susceptibility mapping.