Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

Coastal regions are continually plagued by high water levels induced by river flooding or hurricane induced storm surges. As with any protective structure, it is essential to understand potential problematic regions which could result in a devastating loss for the regions nations value most. Coastal protective systems are primarily comprised of floodwalls and levees, each of which has practiced methodologies utilized for estimating their performance under design conditions. Methodologies concerning spatial variability are limited however, and transitions where earthen levees merge with floodwalls are considered vulnerable areas to erosion and possible breaching. Physical modeling of a specified levee transition is undergone in a three-dimensional wave basin to evaluate this hypothesis, and the detailed results of this assessment are presented within this thesis. From the physical model testing, analysis of the data reveals that the overtopping rates of the levee transition tend to be larger than traditional overtopping techniques have predicted. The runup values and floodwall wave heights tend to show potential problematic areas and mimic the variation of overtopping along the levee transition. Under the design conditions tested, extreme overtopping conditions and associated water level values propose that in order for the structure to sustain the hydraulic conditions, it must be well protected. It is shown that the variation of the still water level plays the largest role in the magnitude of the measured values, and increasing the peak wave period and wave heights also yields greater overtopping and water levels at the structure. Overall these extreme overtopping rates and water levels experienced at the structure irrefutably expose a greater risk of erosion and breaching of the protective structure than initially predicted. This study highlights the need to understand specific spatial variability along coastal protective systems, and provides a better understanding of the mechanisms affecting overtopping for the specific structure tested.

Bathymetric features such as nearshore sandbars can alter local nearshore hydrodynamic processes such as the production of infragravity energy. These bathymetric features may act to reduce or increase the amount of infragravity energy that reaches the shoreline. To determine the influence of the bathymetric features on infragravity energy, the numerical nearshore processes model XBeach was used to simulate infragravity energy at the shoreline. Numerical simulations were completed for three types of bathymetric scenarios: continuous alongshore bar, bar-rip, and no-bar. The presence of the bar reduces the amount of infragravity energy at the shoreline when compared with the no-bar scenario. This reduction was characterized by modifying an empirical parameterization for significant infragravity swash developed by Stockdon et al. (2006) for barred beaches. Results show that the amount of infragravity energy in the form of swash is dependent on the bar height and depth, in addition to the offshore wave height and wavelength. The bar-rip bathymetry produces significant alongshore variation in infragravity energy. The alongshore variations may be due to refracted wave energy or the production of an edge wave by the rip. The magnitude of infragravity energy in the alongshore direction is found to be correlated with the surf zone width. Finally, erosion for the bar-rip scenario is studied qualitatively. The shape of the shoreline is modified during storm events, and is found to take the shape of the alongshore distribution of infragravity energy. Since infragravity swash influences beach erosion, results of this research may be used as part of an erosion vulnerability scale. Such information on erosion vulnerability is important for the design of coastal protection systems and the protection of coastal communities.

Lors d'événements météorologiques extrêmes, cyclones ou tempêtes, les états de mer exceptionnels avec un déferlement important provoquent une montée du niveau de l'eau sur le littoral (surcote) et un envahissement des terres émergées amplifié par l'effet du vent. Cela peut causer d'énormes dégâts humains et matériels (Xynthia, février 2010).Dans un premier temps, le but de ce travail était de comprendre les mécanismes hydrodynamiques mis en jeu lors des tempêtes. Pour cela, nous avons mis en place une campagne de mesures dans la grande soufflerie air-eau de l'IRPHE à Luminy. L'objectif était de quantifier le runup des vagues en fonction d'un vent onshore (jusqu'à 15m/s) pour différentes conditions de houle (régulière, irrégulière ou vent seul) mais aussi de connaître les effets du vent sur les caractéristiques de la houle et sur les courants moyens près du rivage.Dans un deuxième temps, un modèle numérique de type Boussinesq dans le domaine temporel a ensuite été développé en tenant compte des effets combinés vagues/vent/déferlement. Ce modèle est basé sur l'approche de Bingham et al. (2009). Il intègre une bathymétrie variable pour modéliser la propagation d'ondes à l'abord du rivage. Un terme d'amplification des vagues par le vent, Jeffreys (1925, 1926), Miles (1957) ainsi qu'un terme de dissipation pour tenir compte du déferlement ont été introduit, Madsen et al. (1997a), Muscari et Di Mascio (2002). Enfin un modèle simple de runup a été implémenté, Hibberd et Peregrine (1979), Lynett et al. (2002). Afin d'être validé le modèle est confronté à diverses expériences de la littérature, ou à des expériences déjà réalisées au sein du laboratoire. / During extreme weather events like cyclones and storms, the extreme states sea withimportant breaking cause a level setup and coastal flooding magnified by strong wind and can cause human and material damage (Xynthia, february 2010).Initially, the aim of this work is to understand the hydrodynamics mechanisms when storms. To understand this, a measurement campaign was carried out in large air/sea facility at Marseille Luminy. The objective was to quantify maximum runup due to the wind and waves during onshore wind (up to 15m/s) for different conditions of waves (regular, irregular or only wind) and also to know the effect of wind on the waves characteristics and currents near the shore.A Boussinesq-type model in time domain has been developed taking into account the combined effects of wave/wind/breaking. The model that we use is based on the model developed by Bingham et al. (2009). It incorporates a variable bathymetry to simulate the propagation of the waves from offshore to the coastal environment. Amplification of waves by wind is added in two different ways. Jeffreys (1925, 1926), Miles (1957) and to take into account the dissipation of wave, we included a dissipation term, Madsen et al. (1997a), Muscari and Di Mascio (2002). Finally, we introduced the simple runup model of Hibberd et Peregrine (1979), Lynett et al. (2002). In order to validate the model, we have compared our results with differents experiments.

Der vorliegende Band „Regionale Bedeutung von Hochschulen und Forschungseinrichtungen - Das Beispiel Potsdam.“ gibt einen Einblick in die Ergebnisse eines Studienprojekts am Institut für Geographie der Universität Potsdam. Das Studienprojekt war eingebettet in das URBACT II Projekt RUnUP (Role of Universities in Urban Poles). Bei den unterschiedlichen Beiträgen stehen die vielfältigen Beziehungen zwischen Stadt/Politik, Wirtschaft und Wissenschaft in der Region Potsdam im Mittelpunkt. Den theoretischen Bezug bildet dabei das Triple Helix Modell. / The volume in hand, “Regional significance of universities and research institutions – The case study Potsdam”, gives an insight into the research findings of a student project carried out at the University of Potsdam’s Department of Geography. The student project was embedded in the URBACT II project RUnUP (Role of Universities in Urban Poles). The various contributions focus on the multifarious relationships between city/politics, industry and science in the region of Potsdam. The Triple Helix Model forms the theoretical basis of the project.

Malgré les nombreuses études qui ont été effectuées en raison des applications directes au niveau de l’érosion côtière, les processus physiques qui régissent la morphodynamique des plages nécessitent d’être mieux définis. L’objectif de ce travail est d’apporter une contribution à l’étude de ces processus à partir d’une modélisation physique bien contrôlée, menée dans un canal de 10 m de long du LOMC. Le cas particulier des plages intermédiaires selon la classification de Masselink & Short (1993) et mégatidal à marnage relatif faible est considéré. L’évolution temporelle des profils de plage est suivie par méthode acoustique. L’évolution de la surface libre au large et dans la zone de levée de la vague est enregistrée à l’aide de sondes résistives. La surface libre et le fond sableux sont suivis dans la zone de déferlement, la zone de surf et la zone de swash avec une méthode optique. L’effet de la marée sur les profils de plage a été analysé. Une barre intertidale (slip-face bar) est générée et leur processus de formation est analysé mettant en évidence le rôle de la barre subtidale et du déplacement des zones hydrodynamiques d’action au cours du cycle de marée. La dynamique du swash sur une plage mégatidale est étudiée par méthode optique. Une analyse détaillée de la dépendance du runup vis-à-vis des différentes variables est conduite. Celle-ci a permis d’identifier les paramètres les plus appropriés pour prédire le runup. Les résultats montrent qu’il est préférable d’utiliser la pente de la zone de surf et la hauteur de la houle au point de déferlement pour estimer cette grandeur. Une nouvelle formule de calcul du runup adaptée aux plages étudiées est développée. / Numerous studies have been carried out on sandy beach morphology; however, the physical processes which govern beach morphodynamics need to be better defined, despite the significance of this subject in view of the direct applications for coastal erosion. The aim of the present work is to bring a contribution to the study of these processes from well controlled tests carried out in a 10 m long wave flume at LOMC laboratory with a megatidal regime simulation. The tests were performed in the intermediate regime according to the Masselink and Short (1993) classification. The temporal evolution of beach profiles was obtained using an acoustic method. The incident waves and the free surface in the shoaling zone were measured with resistive probes. The free surface and bed level in the breaker, surf and swash zones were recorded with an optical method. The effect of tides on beach profiles was analyzed. Intertidal bar identified as a slip-face bar was generated. Formation processes of this bar were analyzed. The bar is alternately exposed to swash zone processes at low tide and breaker zone processes at high tide. The intertidal bar is fronted by a subtidal bar involved in its formation. Swash hydrodynamics were investigated on a megatidal beach using an optical method. A detailed analysis of the relationship between measured runup elevations and various variables was carried out. This allowed to determine the best parameters to predict runup. The results suggested that the slope of the surf zone and the wave breaking height should be used to estimate runup. A new runup estimation formula adapted to the studied beaches was proposed.

Ce travail de recherche s’inscrit dans le contexte actuel d’accroissement de la vulnérabilité de l’Homme et des activités humaines face aux risques littoraux (aléas érosion et submersion marine), en lien avec les changements environnementaux globaux (élévation du niveau moyen relatif des océans et augmentation de la fréquence et de la virulence des tempêtes) et à la concentration de la population sur le littoral. Suite à la tempête Xynthia du mois de février 2010, l’Etat français s’est doté d’une Stratégie Nationale de Gestion Intégrée du Trait de Côte visant à mettre en place de nouvelles approches en matière de gestion du trait de côte, et notamment, favoriser le repli stratégique contre la défense côtière à tout prix. La mise en place de cette stratégie doit avant tout s’appuyer sur la mise en place d’un réseau d’observation et de suivi de l’évolution du trait de côte à l’échelle de la France. Ce travail s’inscrit dans cette problématique. Il a eu pour objectif d’étudier les dynamiques du trait de côte des plages sableuses et des cordons de galets (formes d’accumulation) de la Bretagne, à différentes échelles spatio-temporelles. Sur le long terme, l’analyse a consisté dans un premier temps à établir une typologie des côtes d’accumulation suivant différents critères morphosédimentaires ; la cinématique du trait de côte a ensuite été analysée à l’échelle des soixante dernières années (1950-2010) à partir d’une étude diachronique par photogrammétrie. Sur le moyen terme, l’analyse s’est faite dans le cadre des suivis topomorphologiques réalisés à l’échelle pluriannuelle à pluridécennale, de plusieurs sites ateliers de l’ODC (IUEM) et/ou du SNO Dynalitt. L’étude des changements morphosédimentaires s’est accompagnée d’une analyse de données de houle, de marée, de vent, et de pression atmosphérique, dans le but d’expliquer la part de ces forçages dans l’alternance de phases d’érosion et de périodes de régénération. Enfin sur le court terme, cette analyse s’est basée sur des levés topomorphologiques à haute fréquence réalisés au cours de l’hiver tempétueux 2013-2014. A cela, s’est ajoutée une étude expérimentale visant à quantifier le runup, dans le but d’analyser l’impact des niveaux d’eau extrêmes à la côte sur l’érosion du trait de côte. De manière globale, la quantification des variations du trait de côte sur le long terme a mis en évidence une tendance à l’érosion (27 % de linéaire étudié), une progradation du trait de côte non négligeable (20,5 % de linéaire) ainsi qu’une importante artificialisation du trait de côte (34,5 % de linéaire). La similitude des réponses morphosédimentaires des cordons littoraux étudiés aux conditions météomarines a permis d’identifier cinq phases distinctes. Trois phases morphogènes (de 1998 à 2003 ; de l’hiver 2006/07 au printemps 2008 ; de l’hiver 2012/13 à aujourd’hui), caractérisées par une érosion importante du trait de côte combinée à une haute fréquence des épisodes tempétueux ; et deux phases au cours desquelles les conditions météomarines ont été plus clémentes (de 2003 à l’hiver 2006/07 ; du printemps 2008 à l’hiver 2012/13), permettant la régénération des cordons littoraux. Au cours de l’hiver 2013-2014, trois tempêtes ont été particulièrement morphogènes en matière d’érosion du trait de côte car elles ont été combinées à de fortes marées de vive-eau : la tempête du 4 et 5 janvier, celle du 1 au 3 février, ainsi que celle du 2 au 3 mars. Durant cet hiver, le recul moyen pour tous les sites étudiés a atteint -6,3 m, avec un maximum d’environ -30,1 m et un minimum de -0,2 m. / 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.

Syfte: Syftet med denna studie är att undersöka hur målföretags runup påverkar den premie sombetalas vid företagsförvärv utifrån substitutions- och markup-prissättningshypotesen. Metod: Studien har en deduktiv ansats där en eventstudie har tillämpats för att samla in relevant sekundärdata från databaserna Thomson Reuters Eikon och Zephyr. För att studera sambandet mellan förvärvspremie och målföretagets runup har en enkel regressionsanalys genomförts och för att studera förklarande variablers påverkan på runup har en multipel regressionsanalys tillämpats. Resultat & slutsats: Studiens resultat visar att det förekommer ett samband mellan runup och den förvärvspremie som betalas vid företagsförvärv. Utifrån substitutions- och markup-prissättningshypotesen visar studien att om runup ökar med 1 % ökar förvärvspremien med 0,879% vilket innebär att en ökning av målföretagets runup är en kostnad för det förvärvande företaget. Förslag till fortsatt forskning: Förslag på vidare forskning är att studera fler förklarande variabler för ett målföretags runup samt att studera volymskillnader i handel av målföretagets aktier dagarna före offentliggörande av bud på exempelvis den svenska marknaden för att se huruvida resultatet skiljer sig från tidigare forskning och andra marknader. Uppsatsens bidrag: Studiens resultat bidrar med kunskap som kan förklara den variation i förvärvspremier som förekommer samt kunskap om att ett målföretags runup är en förvärvskostnad för det förvärvande företaget. / Aim: The purpose of this study is to investigate how the target companies’ runup affects thetakeover premium in mergers and acquisitions based on the substitution and markup pricing hypothesis. Method: The study has a deductive approach in which an event study has been applied to collectrelevant secondary data from the databases Thomson Reuters Eikon and Zephyr. To study the relationship between the acquisition premium and the target company’s runup a simple regression analysis has been conducted and to study the influence of explanatory variables on runup a multiple regression analysis has been applied. Result & Conclusions: The study’s results show that there is a relationship between runup and the takeover premiums. Based on the substitution and markup pricing hypothesis, the study shows that if runup increases by 1 % the takeover premium increases by 0.879 % which means that an increase in the target company's runup is a cost to the acquiring company. Suggestions for future research: Suggestions for further research are to study more explanatory variables for a target company's runup and study volume differences in trading of the target company's shares the days prior to bid announcement on the Swedish market to see if the results differ from previous research and other markets. Contribution of the thesis: The study’s results contribute knowledge that can explain the variation in takeover premiums and knowledge that a target company’s runup in an acquisition is a cost for the acquiring company.

Video monitoring of beaches is becoming the preferred method for observing changes to nearshore morphology. Consequently this work investigates a new technique for predicting the probability of inundation that is based on measuring runup variation using video. Runup is defined as the water-level elevation maxima on the foreshore relative to the still water level and the waterline is defined as the position where the MWL intersects the beach face. Tairua, and Pauanui Beaches, on the north east coast of the North Island of New Zealand, were used as the field site in this study and represent two very different beaches with the same incoming wave and meteorological conditions. Tairua is most frequently in an intermediate beach state, whereas Pauanui is usually flatter in nature. In order to rectify runup observations, an estimate of the runup elevation was needed (Z). This was estimated by measuring the variation of the waterline over a tidal cycle from time-averaged video images during a storm event and provided beach morphology statistics (i.e. beach slope (α) and beach intercept (b)) used in the rectification process where Z=aX+b. The maximum swash excursions were digitized from time-stacks, and rectified to provide run-up timeseries with duration 20 minutes. Field calibrations revealed a videoed waterline that was seaward of the surveyed waterline. Quantification of this error gave a vertical offset of 0.33m at Tairua and 0.25m at Pauanui. At Tairua, incident wave energy was dominant in the swash zone, and the runup distributions followed a Rayleigh distribution. At Pauanui, the flatter beach, the runup distributions were approximately bimodal due to the dominance of infragravity energy in the swash signal. The slope of the beach was a major control on the runup elevation; runup at Pauanui was directly affected by the deepwater wave height and the tide, while at Tairua there was no correlation. Overall, the results of the study indicate realistic runup measurements, over a wide range of time scales and, importantly, during storm events. However, comparisons of videoed runup and empirical runup formulae revealed larger deviations as the beach steepness increased. Furthur tests need to be carried out to see if this is a limitation of this technique, used to measure runup. The runup statistics are consistently higher at Tairua and suggests that swash runs up higher on steeper beaches. However, because of the characteristics of flatter beaches (such as high water tables and low drainage efficiencies) the impact of extreme runup elevations on such beaches are more critical in regards to erosion and/ or inundation. The coastal environment is of great importance to Māori. Damage to the coast and coastal waahi tapu (places of spiritual importance) caused by erosion and inundation, adversely affects the spiritual and cultural well-being of Māori. For this reason, a chapter was dedicated to investigating the practices used by Māori to protect and preserve the coasts in accordance with tikanga Māori (Māori protocols). Mimicking nature was and still is a practice used by Māori to restore the beaches after erosive events, and includes replanting native dune plants and using natural materials on the beaches to stabilize the dunes. Tapu and rahui (the power and influence of the gods) were imposed on communities to prohibit and prevent people from free access to either food resources or to a particular place, in order to protect people and/ or resources. Interpretations of Māori oral histories provide insights into past local hazards and inform about the safety and viability of certain activities within an area. Environmental indicators were used to identify and forecast extreme weather conditions locally. Māori knowledge of past hazards, and the coastal environment as a whole, is a valuable resource and provides a unique source of expertise that can contribute to current coastal hazards management plans in New Zealand and provide insights about the areas that may again be impacted by natural hazards.

Magíster en Ciencias, Mención Geofísica / Ingeniero Civil Matemático / Las alturas máximas del tsunami (alturas de runup) son unos de los parámetros de mayor interés, ya que su predicción estima el peligro al cual se ve expuesta la población. Bajo esta perspectiva, el objetivo principal de este trabajo es estudiar, desde un punto de vista teórico, el comportamiento del runup a lo largo de la costa. Se ha escogido una batimetría simple, del tipo sloping beach, para aproximar a primer orden la geometría de la subducción chilena, bajo la cual se aplicó la teoría de la mecánica de fluidos. Se ha hecho una revisión exhaustiva de la teoría clásicamente utilizada, en los casos unidimensional (lineal y no lineal) y bidimensional lineal, que corresponden a las ecuaciones de aguas poco profundas. Para el cálculo del runup en el caso unidimensional se han utilizado formas de ondas iniciales incidentes de tipo solitarias, que corresponden a la solución más regular de la ecuación de Korteweg-De Vries. También se han usado otras formas de onda iniciales, como las llamadas N-waves, que son una solución particular de la ecuación de generación de tsunamis linealizada en una dimensión. En el caso no lineal, se presenta un método de resolución basado en la teoría de los invariantes de Riemann para sistemas hiperbólicos, conciliando con los resultados de la teoría lineal, y obteniéndose así el ya conocido resultado que, a primer orden, el runup es bien estimado por la teoría lineal. En el caso bidimensional, se ha encontrado una solución para la altura de la ola en el caso de una batimetría de sloping beach, donde se han resuelto las ecuaciones bajo las hipótesis de la teoría lineal. Se ha verificado que el núcleo de las ecuaciones y la geometría, generaliza adecuadamente el caso unidimensional bajo condiciones de borde idénticas. Para ello, se ha hecho un análisis de sus polos y ceros en el plano complejo, para su posterior tratamiento integral, obteniéndose los resultados esperados. Para situaciones especiales, considerando algunas simplificaciones, se ha encontrado una generalización del cálculo analítico aproximado del runup en dos dimensiones tomando en cuenta el ángulo de incidencia de la ola inicial sobre la costa. Se ha encontrando una dependencia explícita con este factor, y así, en este estudio se propone un modelo analítico de la distribución de runup a lo largo de la costa, del que sólo existían modelos empíricos basados en observaciones y simulaciones numéricas. El modelo teórico analítico propuesto ha sido, además, comparado con el modelo numérico NEOWAVE, encontrándose que en el dominio de validez de la solución teórica, ésta estima adecuadamente el máximo runup, concluyendo así la generalización buscada. Para esta verificación, se exploraron varios valores de los parámetros (pendiente de la playa, ángulo de incidencia y altura de la ola inicial, etc.), que inciden directamente en el valor final del runup. Como última aplicación a datos reales, se ha utilizado el modelo teórico propuesto en este trabajo para estudiar la distribución de runup en la costa del tsunami generado por el terremoto del Maule, Mw 8.8 del 27 de febrero del 2010, obteniéndose mejoras en la curva que ajusta dicha distribución, en comparación con otros modelos empíricos preexistentes.