As desembocaduras são ambientes altamente dinâmicos com suas feições sedimentares representando a complexa interação entre as correntes de maré, descarga fluvial, ondas e a batimetria local. Essas feições arenosas possuem uma forte influência na troca sedimentar das regiões costeiras, afetando a estabilidade das regiões adjacentes como as praias e os sistemas estuarinos. O objetivo do presente trabalho é entender a relativa influência dos principais processos que controlam a evolução morfológica dos bancos arenosos e dos pontais arenosos associados a desembocadura do sistema estuarino do rio Caravelas. Este sistema é formado por diversos canais meandrantes conectados com o oceano através de duas desembocaduras, e está localizado em frente ao parcel de Abrolhos no sul da Bahia. Baseado na coleta de dados de duas campanhas de 16 dias no sistema estuarino, o modelo numérico MIKE21-FM (DHI Water \\& Environment) foi aplicado e validado a fim de avaliar quantitativamente os processos que controlam o sistema. Os módulos hidrodinâmico, propagação de ondas e de transporte de sedimentos do modelo numérico foram utilizados neste estudo. O modelo inclui a retroalimentação das mudanças morfológicas nos cálculos da hidrodinâmica, ondas e transporte de sedimentos. Os experimentos numéricos têm como objetivo avaliar a importância relativa das forçantes físicas no ambiente. Foram elaborados dez experimentos numéricos incluindo condições energéticas extremas, alta energia (alta altura de ondas, descargas e maré de sizígia) e baixa energia (pequena altura de ondas, descarga e maré de quadratura) para um intervalo de direções de ondas; e dois períodos adicionais que incluem as condições medidas na coleta de dados (Período 2008 e Período 2007). Imagens de satélites LANDSAT e CBERS também foram utilizadas para observação das mudanças morfológicas do pontal arenoso e da linha de costa adjacente ao longo dos últimos anos. Os resultados para a calibração e validação do modelo numérico aplicado demostraram que na região de interesse e na plataforma interna o modelo consegue reproduzir o padrão da hidrodinâmica de forma adequada. Os resultados mostraram que a morfodinâmica local é controlada pela interação dos principais processos físicos, entretanto a importância relativa de cada um varia ao longo das diferentes regiões do sistema. A morfologia do canal principal e o transporte de sedimentos são controlados pelos fluxos de maré. Os bancos arenosos são também controlados pela maré, porém as correntes geradas por ondas atuando sobre estes bancos, geram um transporte de sedimentos em direção à costa. O pontal arenoso Ilha do Pontal do Sul é influenciado pelas ondas e pela maré. O mecanismo de transporte de sedimentos no pontal deve-se principalmente a corrente de deriva litorânea gerada pelas ondas e a maneira como os sedimentos são depositados e transportados ao longo do pontal deve-se aos fluxos de maré. Pelas imagens de satélites, observou-se que ao longo dos anos, o pontal apresentou uma acresção em seu comprimento, um afinamento da largura e sua extremidade encurvou-se. Este formato do pontal é consequência da corrente longitudinal a qual varia em diferentes escalas de tempo: variação diária devido à maré e variação sazonal devido à mudanças na direção da incidência das ondas. / Tidal inlets are highly dynamic environments with their sedimentary features representing the complex interaction of tidal currents, river discharge, waves and the local bathymetry. These sedimentary features have a strong influence in morphological changes of coastal regions, affecting the stability of the adjacent environment such as beaches and estuarine systems. The aim of this study is to better understand the relative influence of the main processes controlling the morphological evolution of sandbars and sandspits associated to the inlet system of the Caravelas estuary. The Caravelas estuarine system comprises several meandering channels connected to the ocean by a double inlet system located in front of the Abrolhos reef in the south of Bahia. Based on the data collected during two 16-day field experiments in the estuarine system, the numerical model MIKE21 FM (DHI Water \\& Environment) has been applied and validated in order to assess quantitatively the processes that control the system. The hydrodynamic, wave propagation and sediment transport modules of the numerical model were used in this study. The model includes the feedback of morphological changes on hydrodynamic, wave and sediment transport calculations. Numerical experiments aiming to assess the relative importance of the physical forcings on the environment include ten sets of boundary conditions. These include the extreme energetic conditions, for high (large wave heights, river discharge and spring tides) and low energy (small wave heights, river discharge and neap tides) under a range of wave directions; and two additional periods that include the measured conditions (2008 period and 2007 period). Satellite images (LANDSAT and CBERS) were also used to observe the morphological changes of the sandspits and adjacent coastline during the last years. The results from the calibration and validation of the numerical model showed that in the region of interest and the inner shelf the model represents the hydrodynamic patterns. Results show that the local morphodynamics is controlled by the interaction of the main physical processes, being however its relative importance variable along the different regions of the system. Tidal flows control the sediment transport and morphology of the main inlet channel. The sandbars that form the ebb-tidal delta are also tide-dominated, although wave driven currents drive an onshore sediment transport component. The sandspit is influenced by waves and tides. The sediment transport along the sandspit is controlled by longshore drift and then redistributed by tidal currents. Satellite images show the sandspit growing in length, and becoming narrower with a recurved tip. The design of the recurved spits that comprise the inlet is a consequence of the wave generated longshore drift which varies at different time scales: a daily cross-shore variation due to the varying water level and seasonally due to variations in the direction of wave incidence.

As desembocaduras são ambientes altamente dinâmicos com suas feições sedimentares representando a complexa interação entre as correntes de maré, descarga fluvial, ondas e a batimetria local. Essas feições arenosas possuem uma forte influência na troca sedimentar das regiões costeiras, afetando a estabilidade das regiões adjacentes como as praias e os sistemas estuarinos. O objetivo do presente trabalho é entender a relativa influência dos principais processos que controlam a evolução morfológica dos bancos arenosos e dos pontais arenosos associados a desembocadura do sistema estuarino do rio Caravelas. Este sistema é formado por diversos canais meandrantes conectados com o oceano através de duas desembocaduras, e está localizado em frente ao parcel de Abrolhos no sul da Bahia. Baseado na coleta de dados de duas campanhas de 16 dias no sistema estuarino, o modelo numérico MIKE21-FM (DHI Water \\& Environment) foi aplicado e validado a fim de avaliar quantitativamente os processos que controlam o sistema. Os módulos hidrodinâmico, propagação de ondas e de transporte de sedimentos do modelo numérico foram utilizados neste estudo. O modelo inclui a retroalimentação das mudanças morfológicas nos cálculos da hidrodinâmica, ondas e transporte de sedimentos. Os experimentos numéricos têm como objetivo avaliar a importância relativa das forçantes físicas no ambiente. Foram elaborados dez experimentos numéricos incluindo condições energéticas extremas, alta energia (alta altura de ondas, descargas e maré de sizígia) e baixa energia (pequena altura de ondas, descarga e maré de quadratura) para um intervalo de direções de ondas; e dois períodos adicionais que incluem as condições medidas na coleta de dados (Período 2008 e Período 2007). Imagens de satélites LANDSAT e CBERS também foram utilizadas para observação das mudanças morfológicas do pontal arenoso e da linha de costa adjacente ao longo dos últimos anos. Os resultados para a calibração e validação do modelo numérico aplicado demostraram que na região de interesse e na plataforma interna o modelo consegue reproduzir o padrão da hidrodinâmica de forma adequada. Os resultados mostraram que a morfodinâmica local é controlada pela interação dos principais processos físicos, entretanto a importância relativa de cada um varia ao longo das diferentes regiões do sistema. A morfologia do canal principal e o transporte de sedimentos são controlados pelos fluxos de maré. Os bancos arenosos são também controlados pela maré, porém as correntes geradas por ondas atuando sobre estes bancos, geram um transporte de sedimentos em direção à costa. O pontal arenoso Ilha do Pontal do Sul é influenciado pelas ondas e pela maré. O mecanismo de transporte de sedimentos no pontal deve-se principalmente a corrente de deriva litorânea gerada pelas ondas e a maneira como os sedimentos são depositados e transportados ao longo do pontal deve-se aos fluxos de maré. Pelas imagens de satélites, observou-se que ao longo dos anos, o pontal apresentou uma acresção em seu comprimento, um afinamento da largura e sua extremidade encurvou-se. Este formato do pontal é consequência da corrente longitudinal a qual varia em diferentes escalas de tempo: variação diária devido à maré e variação sazonal devido à mudanças na direção da incidência das ondas. / Tidal inlets are highly dynamic environments with their sedimentary features representing the complex interaction of tidal currents, river discharge, waves and the local bathymetry. These sedimentary features have a strong influence in morphological changes of coastal regions, affecting the stability of the adjacent environment such as beaches and estuarine systems. The aim of this study is to better understand the relative influence of the main processes controlling the morphological evolution of sandbars and sandspits associated to the inlet system of the Caravelas estuary. The Caravelas estuarine system comprises several meandering channels connected to the ocean by a double inlet system located in front of the Abrolhos reef in the south of Bahia. Based on the data collected during two 16-day field experiments in the estuarine system, the numerical model MIKE21 FM (DHI Water \\& Environment) has been applied and validated in order to assess quantitatively the processes that control the system. The hydrodynamic, wave propagation and sediment transport modules of the numerical model were used in this study. The model includes the feedback of morphological changes on hydrodynamic, wave and sediment transport calculations. Numerical experiments aiming to assess the relative importance of the physical forcings on the environment include ten sets of boundary conditions. These include the extreme energetic conditions, for high (large wave heights, river discharge and spring tides) and low energy (small wave heights, river discharge and neap tides) under a range of wave directions; and two additional periods that include the measured conditions (2008 period and 2007 period). Satellite images (LANDSAT and CBERS) were also used to observe the morphological changes of the sandspits and adjacent coastline during the last years. The results from the calibration and validation of the numerical model showed that in the region of interest and the inner shelf the model represents the hydrodynamic patterns. Results show that the local morphodynamics is controlled by the interaction of the main physical processes, being however its relative importance variable along the different regions of the system. Tidal flows control the sediment transport and morphology of the main inlet channel. The sandbars that form the ebb-tidal delta are also tide-dominated, although wave driven currents drive an onshore sediment transport component. The sandspit is influenced by waves and tides. The sediment transport along the sandspit is controlled by longshore drift and then redistributed by tidal currents. Satellite images show the sandspit growing in length, and becoming narrower with a recurved tip. The design of the recurved spits that comprise the inlet is a consequence of the wave generated longshore drift which varies at different time scales: a daily cross-shore variation due to the varying water level and seasonally due to variations in the direction of wave incidence.

Climate change is predicted to alter the rainfall patterns in the future, and extreme rain events with large rainfall volumes will become more frequent and intense which increases the flood risk. A clear trend can be seen, where more and more people decide to relocate from rural to urban areas. The concentration of people, infrastructure, businesses and social services in urban areas makes them particularly vulnerable to floods due to the large economic consequences that ensue. Analyzing the future flood risk is therefore of high importance in order to adapt to the changing climate and lower the consequences of future floods. Estimating the flood risk of an area is complicated and usually abstract, especially as i) the definition and understanding of risk varies a lot, ii) there is a large shortage of consistent data and iii) decision management plans are made several years ahead even though it’s hard to predict how cities will evolve. In a hydro-economical flood risk analysis, the risk is expressed in monetary terms, here in terms of Expected Annual Damage (EAD). In order to calculate the true risk of an area, EAD, for any given year there is a need of calculating all consequences for “all” events. With today’s technical limitations it is not possible to compute all possible events in an effective way, which makes the practice both time-consuming and expensive, therefore usually only a several events are considered. Among others, this paper aim to give a better understanding of how this several events should be picked to still get a good estimation. A flood risk assessment of the city Tierp, Sweden, was performed as part of the master thesis for use as decision support. The flood hazard was mapped through hydrodynamic modelling using the 2D-modelling program MIKE21 developed by DHI. The model simulated the future flood extent in the year 2100 by using precipitation corresponding to the return periods 1, 2, 5, 10, 20, 30, 50, 100, 200 and 500 years, with a climate factor of 1.25. The economic consequences were evaluated in the DHI program City Adaptation Decision Support System (CADSS) where the flood maps were overlaid with assets of different categories with assigned damage costs. The program allowed calculation of the flood risk in terms of an expected annual damage (EAD), and the choice and combination of return periods when calculating the EAD was assessed to see how it affects the outcome. Furthermore, sustainable drainage systems (SuDS) were implemented in the hydrodynamic model and a hydro-economic analysis was performed through a cost-benefit analysis to find the optimum design return period of the structures. The flood risk assessment showed that Tierp would face an EAD of 4 304 181 SEK in the year 2100 if climate change predictions proved accurate. The accuracy of the EAD calculation was found to increase with the number of included return periods, where the inclusion of lower return periods was seen to have a larger impact on the outcome compared to higher return periods. The hydro-economic optimization of mitigation structures concluded that the optimum design return period is 50 years, and the benefit of implementing SuDS of larger dimensions is minimal. However, more dimensions need to be included in the optimization to validate this result.  Flood risk assessments have a large potential for being used as decision support in Sweden, but lack of national damage cost data makes the result uncertain and difficult to validate. More research would also be required to better understand the relation between floods and the damage they cause for Swedish conditions. / I takt med klimatförändringarna förutspås extrema regnhändelser med stora regnmängder och hög intensitet att öka i framtiden. Samtidigt väljer allt fler människor att flytta från landsbygden in till städerna vilket bidrar till att exponering av sårbara värden som människor, infrastruktur och verksamheter koncentreras. Det i sin tur innebär att risken för översvämning ökar, då översvämningarna förväntas ske mer frekvent samtidigt som risken för att konsekvenser uppstår till följd av översvämningen ökar. För att förebygga översvämningar eller minska risken i framtiden krävs en hållbar stadsplanering, där första steget är att försöka estimera översvämningsrisken inom ett område. Uppskattning av översvämningsrisken är komplicerat. Dels eftersom i) definitionen och kunskapen av risk varierar mycket, ii) det råder stor brist på data och iii) planering och beslut görs flera år i förväg, samtidigt som det är svårt att förutsäga hur städerna kommer att utvecklas. I en ekonomisk riskanalys av översvämningar uttrycks risken i monetära termer som i denna rapport definierats som förväntad årlig skada (Expected Annual Damage, EAD). För att beräkna den verkliga risken för ett område, EAD, för ett visst år måste man beräkna alla konsekvenser för ”alla” händelser. På grund av dagens tekniska begränsningar är det inte möjligt att beräkna alla sannolika händelser på ett effektivt sätt vilket gör det både tidskrävande och dyrt. Syftet med denna rapport är därför bland annat att ge en bättre förståelse för hur ett urval av händelser kan göras för att ändå ge en bra uppskattning. En del av masteruppsatsen bestod i att kartlägga översvämningsrisken i staden Tierp, Sverige. Översvämningsrisken simulerades genom hydrodynamisk modellering med hjälp av 2D-modelleringsprogrammet MIKE 21, utvecklat av DHI. Med hjälp av modellen simulerades den framtida översvämningsutbredningen år 2100 vid nederbörd med återkomsttiderna 1, 2, 5, 10, 20, 30, 50, 100, 200 och 500 år, med en klimatfaktor på 1,25. De ekonomiska konsekvenserna utvärderades i DHI-programmet City Adaptation Decision Support System (CADSS) där översvämningskartor jämfördes med kategoriserade byggnader och dess respektive förväntade skadekostnader. Med hjälp av CADSS kunde översvämningsrisken i form av EAD beräknas, och kombinationen av olika återkomstperioder vid beräkningen av EAD kunde bedömas för att se hur det påverkar resultatet. Utöver detta implementerades hållbara skyfallslösningar i den hydrodynamiska modellen och en hydroekonomisk analys utfördes genom en kostnads-nyttoanalys för att hitta den optimala designåterkomsttiden för lösningarna. Bedömningen av översvämningsriskerna visade att Tierp skulle drabbas av en EAD på 4 304 181 SEK år 2100 om de förväntade klimatförändringarna visar sig vara korrekta. Noggrannheten i EAD-beräkningen visade sig öka med antalet inkluderade återkomsttider, där inkluderandet av lägre återkomsttider visade sig ha en större inverkan på resultatet jämfört med högre återkomsttider. Den hydroekonomiska optimeringen av begränsningsstrukturer ledde till slutsatsen att den optimala återkomstperioden är 50 år, och att nyttan av att införa skyfallslösningar dimensionerade för större återkomsttider är minimal. Fler dimensioner måste dock inkluderas i optimeringen för att bekräfta detta resultat.  Bedömningar av översvämningsrisker har en stor potential att användas som beslutsstöd i Sverige, men bristen på nationella uppgifter om skadekostnader gör resultatet osäkert och svårt att validera. Det krävs även mer forskning för att bättre förstå relationen mellan översvämningar och de skador de orsakar för svenska förhållanden.

Climate change and environmental disasters are strongly dependent. Humanity is facing considerable changes in environmental adaptions and remediation of contaminated sites. Water is a valuable resource that should be protected and prevented from hazardous influences. One of the main water quality problems is the excess of nutrients causing algae blooming. Many surface-and groundwaters have lost the ability to be used as anthropogenic water sources and other purposes (recreation, water supply, irrigation, etc.). Both nutrients and other substances impact water quality and climate change, making it challenging for modern society to maintain good water quality. Moreover, extreme rainfalls become more common, temporarily increasing surface runoff and exceeding infiltration capacity during high-intensity rainfall events. Water that is not capable of infiltration in the soil will run on the watershed into depressions and be infiltrated or spread to downstream catchments. This water might contain hazardous substances, e.g., nutrients, thereby enhancing water contamination in nearby waters. The investigation is made in how nutrients (P – phosphorus and N – nitrogen) spread depending on surface runoff from cloudburst in Hörby municipality in southern Sweden, Skåne-region. The land-use of the site is investigated, where pervious-and impervious areas are defined and further classified in more specific sub-groups. Different rain returns periods used to provide clear explanation of how the nutrient spreading is taking place and how rain intensity is impacting spreading of N and P. Furthermore, the sources of nutrient load are detected and investigated with a hydraulic model. The results show that the hydrodynamic model can be used to visualize the spread and determine the accumulated concentration in the flood area. Furthermore, rainfall mapping has been carried out to identify vulnerable areas in the landscape and determine critical parameters such as distribution and maximum water depth. The method's application area has been discussed in the industry's interest in studying cloudburst more simply and cost- effectively in parallel with nutritional load problems. / Klimatförändringar och miljökatastrofer är starkt beroende händelser. Mänskligheten står inför betydande förändringar i miljöanpassningar och sanering av förorenade platser. Vatten är en värdefull resurs som bör skyddas och förhindras från farlig påverkan. Ett av de viktigaste vattenkvalitetsproblemen är överflödet av näringsämnen som orsakar alger som blommar. Många yt- och grundvattenkällor har förlorat förmågan att nyttjas som dricksvattenkällor samt källor för andra ändamål (rekreation, vattenförsörjning, bevattning etc.). Både näringsämnena och andra kemikalietyper påverkar vattenkvaliteten och klimatförändringarna, vilket gör det utmanande för det moderna samhället att upprätthålla god vattenkvalitet. Dessutom blir extrema regn i form av skyfall vanligare och ökning i avrinning från ytor som överstiger infiltrationskapaciteten under högintensiva regnhändelser. Vatten som inte kan infiltrera i marken kommer att rinna längst avrinningsområdet till låga punkter och infiltreras eller spridas till nedströms avrinningsområden. Den rinnande vatten kan innehålla farliga ämnen, t.ex. näringsämnen, vilket kan bidra till ökade föroreningar i närliggande vattendrag. Undersökningen görs i hur näringsämnen (P - fosfor och N - kväve) sprids beroende på ytavrinning från skyfall i Hörby kommun, Skåne, i södra Sverige. Områdets markanvändning undersöks, där genomträngliga och ogenomträngliga ytor definieras och klassificeras ytterligare i mer specifika undergrupper. Olika återkomsttider på regn används för att ge en förklaring på hur närsaltsspridningen sker och hur regnintensiteten påverkar spridningen av fosfor och kväve. Vidare upptäcks och undersöks källorna för näringsbelastning med en hydraulisk modell. Resultaten visar att den hydrodynamiska modellen kan användas för att visualisera spridningen och bestämma den ackumulerade näringsbelastningen i översvämningsområdet. Dessutom har skyfallskartering genomförts för att identifiera utsatta områden i landskapet och bestämma kritiska parametrar som fördelning och maximalt vattendjup. Metodens applikationsområde har diskuterats av kommersiellt intresse i att studera skyfall på ett enkelt och kostnadseffektivt sätt parallellt med närsaltsbelastningen.

There is a growing interest in tidal energy, owing to its predictable nature in comparison to other renewable sources. In the case of the UK, its importance also lies on the availability of exploitable areas as well as their total capacity, which is estimated to cover more than 20% of the country demand. However, the level of development of this kind of technology is still far behind other types of renewable energy. However, several studies focused on a variety of individual devices, followed by more recent research on the deployment of large arrays or tidal farms. Potential sites for energy extraction can be found in narrows between islands and the coast or estuaries. The latter present some advantages for the installation and the connection to the grid but estuaries are often prone to flood risk from tides and surges. Therefore, the objective of this thesis is to evaluate the effect that very large groups of turbines could have on peak water levels during flooding events in the case of being deployed in estuarine areas. For that purpose, a new methodology has been developed, which implies the use of a numerical model (MIKE 21 by DHI), and it has been demonstrated against a real case study in the UK: the Solway Firth estuary. Another objective has consisted of integrating in this thesis the results from detailed CFD modelling and optimisation techniques involved in the project. A literature review has been carried out in order to identify the current state of the art for the different subjects considered in the thesis. Different aspects of the numerical model used for this study (MIKE 21) have been presented and the modelling of the turbines within the code has been validated against experimental and CFD data. The procedure to include large numbers of turbines in the code is also developed. An analysis has been done of the different estuaries existing in the UK suitable for tidal energy extraction, identifying their main geometrical features. Based on this, idealised models of estuaries have been used to assess the influence that the channel geometry could have on the impact of tidal farms under extreme water levels. The effect has been measured by comparing the results of the numerical model between the case with and without turbines under different flooding scenarios. Finally, the same methodology has been applied to a real case study selected from the previous group of estuaries namely the Solway Firth. An initial model has been created, according to the available data at the start of the research, which contained some errors related to the water depth at the intertidal areas in the upper estuary. Therefore, when a more realistic dataset became available, an improved model was created. The improved model has been used to assess the effects of tidal farms in the estuary under a coastal flooding event. It is concluded that there is significant influence of the channel geometry over the locations where the maximum changes in water levels due to the tidal farms will happen. Nevertheless, the effects seem to be more relevant in terms of the decrease rather than the increase of peak water levels for all geometries and the maximum changes seem to be in the order of dm. This is in agreement with the results of the Solway Firth models and can be summarised as a positive net effect over flood risk. On the other hand, a concern has been raised about the impact on intertidal areas, which could be the subject of future research.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A fim de compreender e predizer evoluÃÃes geomorfologicas em mares e em estuÃrios litorais necessita-se de um modelo que descreva a dinÃmica do movimento da Ãgua, o movimento do sedimento e a evoluÃÃo de limites erodiveis (como o fundo). Os Ãltimos dois mÃdulos requerem a informaÃÃo quantitativa sobre a erosÃo, a deposiÃÃo e o transporte do sedimento. As estruturas sÃo construÃdas ao longo da costa para vÃrias finalidades e causam modificaÃÃes no ambiente natural com mudanÃa circunstanciais da linha de costa. A concepÃÃo do porto de PecÃm requereu do governo estudar e impedir as possÃveis alteraÃÃes da linha da costa prÃximo Ãs estruturas construÃdas. EntÃo, atravÃs de simulaÃÃo numÃrica, utilizando-se moderno software, MIKE21 e LITPACK, estudou-se e previu-se o comportamento da linha de costa nos dez anos seguintes ao inÃcio da construÃÃo, 1996. Este trabalho pretende verificar a realidade daquela previsÃo. Os resultados para a dinÃmica da linha de costa da regiÃo do porto de PecÃm foram obtidos atravÃs de comparaÃÃes da sua evoluÃÃo desde o momento inicial da construÃÃo do terminal portuÃrio, mostrando, assim, as transformaÃÃes causadas pelo transporte do sedimento em dois perÃodos de estudo, antes e depois da construÃÃo do embarcadouro provisÃrio, e comparar com os resultados determinados pelas simulaÃÃes numÃricas dos softwares, MIKE21 e LITPACK / In order to understand and predict geomorphologic evolutions in coastal seas and estuaries a model is needed which describes the dynamics of the water motion, sediment movement and the evolution of erodible boundaries (like the bottom). The latter two modules require quantitative information about erosion, deposition and transport of sediment. The structures are constructed to the long one of the coast for some purposes and cause modifications in the natural environment with change of the circumstantial shoreline. The conception of the port of PecÃm required of the government to study and to hinder the possible alterations of the coast line next to the constructed structures. Then, through numerical simulation, using modern software, MIKE21 and LITPACK, it was studied and one foreseen the behavior of the shoreline in the ten following years to the beginning of the construction, 1996. This work intends to verify the reality of that forecast. The results for the dynamics of the shoreline of the region of the port of PecÃm had been gotten through comparisons of its evolution since the initial moment of the construction that terminal port, showing, thus, the transformations caused by the transport of the sediment in two periods of study, before and after the construction of the provisory docking, and to compare with the results determined for the numerical simulations of software, MIKE21 and of LITPACK

In this study, the evolution of the numerical water wave models with the theoretical background and the governing equations are briefly discussed and a numerical model MIKE21 BW which can be applied to wave problems in nearshore zone is presented. The numerical model is based on the numerical solution of the Boussinesq type equations formulated on time domain. Nonlinearity and frequency dispersion is included in the model. In order to make comparison between the results of nonlinear shallow water equations with Boussinesq terms, MIKE21 BW and NAMIDANCE are applied to the problem of wave propagation in the long distances and runup on simple and composite slopes. The numerical experiments are applied to Dat&ccedil / a Marina and the results are compared to the results of the physical experiments on wave disturbance in Dat&ccedil / a Marina. In these comparisons the reflection characteristics of different coastal boundaries in the harbor area are tested and the internal parameters in the model are calibrated accordingly. The numerical model MIKE21 BW is applied to skenderun harbor as a case study. The input wave parameters are selected from the wave climate study for Iskenderun Harbor. The model is set up and the agitation inside the harbor is computed according to four different incoming wave scenarios. The disturbance maps inside the harbor for different incoming wave scenarios are obtained. The critical regions v of the harbor according to disturbance under different wave conditions are presented and discussed.

La présente recherche porte sur l'étude de l'écoulement de l'eau dans un canal à surface libre aux abords de structures de restauration tels que les épis. Les épis sont utilisés depuis plusieurs décennies pour contrer les problèmes d'érosion de berges et pour réhabiliter les habitats de poissons. Les problèmes d'érosion de berges sont fréquents et la construction d'épis est une bonne alternative aux techniques de stabilisation de berges structurales tel que l'empierrement : il s'agit d'une solution habituellement moins coûteuse et elle a généralement moins d'impact sur l'environnement. Malheureusement, malgré l'utilisation de ces structures de restauration, la connaissance n'est pas encore assez développée pour permettre à tous les projets de restauration avec épis de connaître le succès escompté. Un mauvais choix de géométrie, d'emplacement dans le cours d'eau ou de profondeur peut mener le projet à l'échec. L'écoulement aux abords de structures de restauration est complexe et plusieurs recherches expérimentales et numériques sont présentement en cours à ce sujet. Ce mémoire présente une recherche qui porte sur trois épis rectangulaires avec une orientation différente (135 degrés, 90 degrés, 45 degrés) confrontés à trois débits différents. Les vitesses mesurées en laboratoire avec un profileur de vitesse acoustique Doppler (ADVP) montrent que l'épi perpendiculaire (90°) est plus influent sur le courant et le potentiel de transport de sédiments que les autres épis. Les contraintes de Reynolds calculées suggèrent aussi que l'épi perpendiculaire serait l'épi qui créerait une zone d'affouillement plus importante que les deux autres épis. Le modèle expérimental a ensuite été modélisé numériquement avec le logiciel d'éléments finis bidimensionnel MIKE21 du Danish Hydraulic Institute (DHI) au Danemark. Les résultats du modèle sont fidèles aux résultats expérimentaux. Une validation a aussi été effectuée avec le logiciel par éléments finis River2D de l'Université d'Alberta. Bien que les vitesses soient légèrement inférieures à celles obtenues par MIKE21 ou en laboratoire, River2D représente bien les distributions générales des vitesses et l'ordre de grandeur de celles-ci. Contrairement à l'opinion de certains chercheurs, qui croient que les logiciels à éléments finis tridimensionnels sont des incontournables pour obtenir une bonne modélisation, les résultats de cette recherche suggèrent que les logiciels d'éléments finis bidimensionnels seraient adéquats pour représenter des projets en rivière.