<p>Denna rapport ger förslag på olika metoder att automatiskt justera flytläget på en statiskt förankrad boj, en överblick över de processer som styr ändringen av vattennivån och en statisktisk analys på vattennivåförändringarna vid Stockholm, Kungsholmsfort och Kungsvik.</p><p>Beroende på vattenivåns variation finns olika metoder för justering. Områden med små variationer av vattennivå lämpar det sig bäst utan någon som helst justering av flytläget. Områden med inte för stora tidvattensförändringar bör justeras med ett system bestående av vinsch, växellåda med en utväxling på 10 000:1, en 12 V DC motor, ett skötselfritt 12 V batteri, en luftlindad linjärgenerator och en trådtöjningsgivare. Områden med stora variationer i tidvatten behöver en avlastning för motorn i form av en fjäder och dämpare. De monteras horizontellt inuti bojen för att skyddas från den yttre miljön.</p><p>Den statistiska analysen påvisade de största vattennivåändringarna vid både Kungsviks och Kungsholmsforts mätstationer, båda uppvisade ett intervall på 1,6 m mellan minimum och maximum. Kungsvik var den station med de största dagliga variationerna, detta på grund av tidvattnets påverkan i området.</p> / <p>This thesis gives examples of different methods of automated adjustment of floatation level for a static moored buoy, an overview of the theories behind water level change and a statistical analysis of the water level changes for Stockholm, Kungsholmsfort and Kungsvik.</p><p>Depending on the range and frequency of the water level change different methods of adjustment are recommended. For areas with small changes in sea level the best choice would be no adjustment of the floatation level. Areas that are influenced by moderate tidal ranges should incorporate a system of regulation consisting of a winch, gearbox with a gear ratio of around 10,000:1, 12 V DC motor, 12 V maintenance free battery, air coiled linear generator and a strain gauge. For areas with large tidal ranges the previous system should be complimented with a horizontally mounted spring, inside the buoy, to lessen the loads on the motor.</p><p>The statistical analysis found the largest extremes in water level of the three sites to be at Kungsvik and Kungsholmsfort, both exhibiting a range of almost 1.6 m. Kungsvik was the station with the largest daily variations, this is because this is the only station influenced by tidal variations.</p>

Natural and local anthropogenic changes in estuaries (e.g., sea-level rise, navigation channel construction and loss of wetlands) interact with each other and produce non-linear effects. There is also a growing recognition that tides in estuaries are not stationary. These factors together are changing the estuarine water level regime, however the implications for extreme water levels remain largely unknown. Changes over the past century in many estuaries, such as channel deepening and streamlining for navigation have significantly altered the hydrodynamics of long waves, often resulting in amplified tides (a ~85% increase in Wilmington, NC since 1900) and storm surge in estuaries. This research focuses on establishing analytical and numerical models that simulate a wide range of systems and flow conditions that combine multiple flood sources: astronomical tide, storm surge, and high river flow. To investigate the effects of estuarine bathymetry conditions (e.g., channel depth, convergence length), hurricane conditions (e.g., pressure and wind field), river discharge, and surge characteristics (e.g., time scale and amplitude and relative phase) on tide and storm surge propagation, I develop an idealized analytical model and two numerical models using Delft-3D. The Cape Fear River Estuary, NC (CFRE), and St Johns River Estuary, FL (SJRE) are used as case studies to investigate flood dynamics. The analytical approach has been compared and verified with idealized numerical models. I use data recovery, data analysis, and idealized numerical modeling of the CFRE to investigate the effects of bathymetric changes (e.g., dredging and channel modification) on tidal and storm surge characteristics over the past 130 years. Data analysis and modeling results suggest that long-term changes in tides can be used along with the tidal analysis tools to investigate changes in storm surge. Analysis indicate that tidal range in Wilmington, NC (Rkm 47) has doubled to 1.55m since the 1880s, while a much smaller increase of 0.07m observed close to the ocean in Southport (Rkm 6) since the 1920s. Further, model results suggest that the majority of long term changes in tides of this system have been caused by deepening the system from 7m to 15.5m due to dredging, rather than by changes in the coastal tides. Numerical modeling using idealized, parametric tropical cyclones suggests that the amplitude of the worst-case, CAT-5 storm surge has increased by 40-60% since the nineteenth century. Storm surges are meteorologically forced shallow water waves with time scales that overlap those of the tidal bands. Using data, I show that the surge wave can be decomposed into two sinusoidal waves. Therefore, I analytically model surge via a 3-constituent analytical tide model, where the third constituent is the dominant semi-diurnal tide and friction is linearized via Chebyshev polynomials. A constant discharge is considered to approximate fluvial effects The analytical model is used to study how surge amplitude, surge time scale, and surge-tide relative phase affect the spatial pattern of amplitude growth and decay, and how depth changes caused by channel deepening influence the magnitude of a storm surge. I use non-dimensional numbers to investigate how channel depth, surge time scale and amplitude, surge asymmetry, and relative timing of surge to tides alter the damping or amplification of surge along the estuary. The non-dimensional numbers suggest that increasing depth has similar effects as decreasing the drag coefficient. Similarly, larger time scale has an equivalent effect on tide and surge as increasing depth due to channel deepening. Analytical model results show that the extent of the surge amplification is dependent on the geometry of the estuary (e.g., depth and convergence length) and characteristics of the surge wave. Both models show that much of the alterations of water levels in estuaries is due to channel deepening for navigation purposes and that the largest temporal change occur for surges with a high surge to D2 amplitude ratio and a short time scale. Model results farther indicate that surge amplitude decays more slowly (larger e-folding) in a deeper channel for all surge time scales (12hr-72hr). Another main finding is that, due to nonlinear friction, the location of maximum change in surge wave moves landward as the channel is deepened. Thus, changes in flood risk due to channel deepening are likely spatially variable even within a single estuary. Next, I use the verified analytical model and numerical models to investigate the effects of river flow on surge wave propagation, and spatial and temporal variability of compound flooding along an estuary. To model the historic SJRE, I digitize nautical charts of SJRE to develop a numerical model. Both the numerical and analytical models are used to investigate the contribution of tide, surge, and river flow to the peak water level for historic and modern system configurations. Numerical modeling results for hurricane Irma (2017) show that maximum flood water levels have shifted landward over time and changed the relative importance of the various contributing factors in the SJRE. Deepening the shipping channel from 5.5m to 15m has reduced the impacts of river flow on peak water level, but increased the effects of tide and surge. Sensitivity studies also show that peak water level decreases landward for all river flow scenarios as channel depth increases. Model results show that the timing of peak river flow relative to the time of maximum surge causes very large changes in the amplitude of total water level, and in river flow effects at upstream locations for modern configuration than for the historic model. Changes in surge amplitudes can be interpreted by the non-dimensional friction number, which shows that depth (h), surge time scale (T=1/w), and convergence length-scale (Le) affect the damping/amplification of both tides and surge waves. Overall, this study demonstrates that a system scale alteration in local storm surge dynamics over the past century is likely to have occurred in many systems and should be considered for system management. The results of this research give the scientists and engineer a better understanding of tide, river flow, and surge interactions, and thereby contribute to an understanding of how to predict storm surges and help mitigate their destructive impacts. Future system design studies also need to consider long-term and changes of construction and development activities on storm surge risk in a broader context than has historically been the case.

Since 2004 there have been multiple devastating tsunamis around the globe triggered by large magnitude earthquakes; with the most recent being the Tohoku, Japan tsunami in March 2011. These tsunamis have caused significant loss of life and damage to the coastal communities impacted by these powerful waves. The resulting devastation has raised awareness of the dangers of tsunamis and the Network for Earthquake Engineering Simulation (NEES) housesmash project (NEEShousesmash), was started to investigate several different areas of tsunami inundation. The work presented in the following two manuscripts was performed at the O.H. Hinsdale Wave Lab and Gene D. Knudson Wood Engineering Lab, which are located at Oregon State University. This work represents a small portion of the total NEEShousesmash project, and is focused on improving the knowledge and predictability of tsunami loading and structural performance. The first manuscript investigates tsunami wave impact on full scale light-frame wood walls, and compares the measured forces to calculated values using the linear momentum equation, previously evaluated by Cross (1967). The results show for each wave height tested a peak transient force followed by a sustained quasi-static force, with a ratio of transient force to quasi-static force of 2.2. The results also show that the linear momentum equation did an acceptable job of predicting the measured transient forces on the walls to within ±10%, and that increased wall flexibility, 2x4 vs. 2x6 dimensional lumber, resulted in lower measured transient forces when subjected to similar tsunami wave heights. These results are important for practical use because the linear momentum equation is a simple equation to use, that only requires a couple of site specific input variables. The second manuscript is a continuation of the work done in the wave lab for the first manuscript. These experiments provide a starting point for expanding the testing of the structural response and performance of larger scale structures subjected to tsunami wave loads. By simulating tsunami loading in a traditional structures laboratory, the inherent limits of testing structural performance in small scale tsunami laboratory facilities is removed. The results show that a light-frame wood shear wall, built to current standards, is susceptible to premature failures from concentrated impact loads at intermediate heights compared to the design strength at full height. It is also shown that the out-of-plane walls subjected to both elastic and inelastic loads behave like a one way slab with minimal load sharing between adjacent studs. The failures observed during the hydrodynamic wave testing of the nailed connection between the bottom plate and studs was successfully reproduced, and shows that current construction standards are not fully utilizing the available capacity of each stud when subjected to tsunami waves. The reinforcement of this connection with traditional metal brackets would help increase the capacity of the out-of-plane wall to resist tsunami wave loads. / Graduation date: 2012

Denna rapport ger förslag på olika metoder att automatiskt justera flytläget på en statiskt förankrad boj, en överblick över de processer som styr ändringen av vattennivån och en statisktisk analys på vattennivåförändringarna vid Stockholm, Kungsholmsfort och Kungsvik. Beroende på vattenivåns variation finns olika metoder för justering. Områden med små variationer av vattennivå lämpar det sig bäst utan någon som helst justering av flytläget. Områden med inte för stora tidvattensförändringar bör justeras med ett system bestående av vinsch, växellåda med en utväxling på 10 000:1, en 12 V DC motor, ett skötselfritt 12 V batteri, en luftlindad linjärgenerator och en trådtöjningsgivare. Områden med stora variationer i tidvatten behöver en avlastning för motorn i form av en fjäder och dämpare. De monteras horizontellt inuti bojen för att skyddas från den yttre miljön. Den statistiska analysen påvisade de största vattennivåändringarna vid både Kungsviks och Kungsholmsforts mätstationer, båda uppvisade ett intervall på 1,6 m mellan minimum och maximum. Kungsvik var den station med de största dagliga variationerna, detta på grund av tidvattnets påverkan i området. / This thesis gives examples of different methods of automated adjustment of floatation level for a static moored buoy, an overview of the theories behind water level change and a statistical analysis of the water level changes for Stockholm, Kungsholmsfort and Kungsvik. Depending on the range and frequency of the water level change different methods of adjustment are recommended. For areas with small changes in sea level the best choice would be no adjustment of the floatation level. Areas that are influenced by moderate tidal ranges should incorporate a system of regulation consisting of a winch, gearbox with a gear ratio of around 10,000:1, 12 V DC motor, 12 V maintenance free battery, air coiled linear generator and a strain gauge. For areas with large tidal ranges the previous system should be complimented with a horizontally mounted spring, inside the buoy, to lessen the loads on the motor. The statistical analysis found the largest extremes in water level of the three sites to be at Kungsvik and Kungsholmsfort, both exhibiting a range of almost 1.6 m. Kungsvik was the station with the largest daily variations, this is because this is the only station influenced by tidal variations.

The research presented in this dissertation attempted to determine whether climate variability is critical to sea level changes in coastal BC. To that end, a number of statistical models were proposed to clarify the relationships between five climate variability indices representing large-scale atmospheric circulation regimes and sea levels, storm surges, extreme winds and storm track variability in coastal BC. The research findings demonstrate that decadal to inter decadal climatic variability is fundamental to explaining the changing frequency and intensity of extreme atmospheric and oceanic environmental variables in coastal BC. The trends revealed by these analyses suggest that coastal flooding risks are certain to increase in this region during the next few decades, especially if the global sea-levels continue to rise as predicted. The out come of this study emphasis the need to look beyond climatic means when completing climate impact assessments, by clearly showing that climate extremes are currently causing the majority of weather-related damage along coastal BC. The findings highlight the need to derive knowledge on climate variability and change effects relevant at regional to local scales to enable useful adaptation strategies. The major findings of this research resulted in five independent manuscripts: (i) Sea level responses to climatic variability and change in Northern BC. The Manuscript (MC) is published in the Journal of atmospheric and oceans (AO 46 (3), 277-296); (ii) Extreme sea-level recurrences in the south coast of BC with climate considerations. This MC is in review with the Asia Pacific Journal of Climate Change (APJCC); (iii) Extreme sea-surge responses to climate variability in coastal BC. This MC is currently in review in the Annals of the AAG (AN-2009-0098); (iv) Extreme wind regime responses to climate variability and change in the inner-south-coast of BC. This MC is published in the Journal of Atmosphere and Oceans (AO 47 (1), 41-62); (v) Sensitivity of winter storm track characteristics in North-eastern Pacific to climate variability. This manuscript is in review with the Journal of Atmosphere and Oceans (AO (1113)). The findings of this research program made key contributions to the following regional sea level rise impact assessment studies in BC: (i) An examination of the Factors Affecting Relative and Absolute Sea level in coastal BC (Thomson et al., 2008). (ii) Coastal vulnerability to climate change and sea level rise, Northeast Graham Island, Haida Gwaii (formally known as the Queen Charlotte Islands), BC (Walker et al., 2007). (iii) Storm Surge: Atmospheric Hazards, Canadian Atmospheric Hazards Network - Pacific and Yukon Region, C/O Bill Taylor.

Les estimations de la remontée générale du niveau de la mer, de l’ordre de 17 ± 2 cm sur le siècle dernier, masquent une réalité très variable d’une région à l’autre. Qu’en est-il du littoral charentais ? Des séries temporelles de plus de 40-50 ans sont souvent indispensables pour tirer des tendances fiables à long terme sur les composantes du niveau marin : niveau moyen de la mer, ondes de marée et effets météorologiques. Or, de nombreux lots de mesures marégraphiques du littoral charentais « sommeillaient » dans les centres d’archive français, i.e. : La Rochelle-Vieux port (1775-1892), La Rochelle-La Pallice (1885-auj.), île d’Aix (1824-auj.), fort Enet (1859-1873), fort Boyard(1873-1909) et Cordouan (1812-1994). Les objectifs de nos travaux de recherche étaient multiples : inventorier,sauvegarder et numériser des lots de mesures historiques du niveau marin, puis construire des séries temporelles recomposées à partir de ces lots de mesures hétérogènes, temporellement et spatialement, et enfin les exploiter pour mieux décrire et comprendre l’évolution à long terme du niveau de la mer. La qualité des trois séries construites (LaRochelle : 1775-auj. ; Aix-Enet-Boyard : 1824-auj. ; et Cordouan : 1812-1994) a ensuite été éprouvée en détail afin d’évaluer le niveau de précision de notre reconstruction. A partir de ces séries inédites, nous avons pu étudier l’évolution des composantes du niveau marin. Suite à ces travaux, nous fournissons un inventaire le plus exhaustif possible détaillant les mesures de 25 observatoires de Charente-Maritime, de 1775 à aujourd’hui. Les données des séries temporelles ainsi que des éléments permettant d’apprécier leur qualité seront bientôt disponibles en ligne sur REFMAR (refmar.shom.fr), SONEL (www.sonel.org) et au PSMSL (www.psmsl.org). Nos résultats positifs nous ont permis de reconstruire une série encore plus globale, celle du pertuis d’Antioche, à partir des moyennes mensuelles du niveau marin des séries de La Rochelle et d’Aix-Enet-Boyard. Parmi les résultats marquants obtenus,le niveau moyen de la mer s’est élevé de +1,38 ± 0,08 mm/an dans le pertuis d’Antioche sur la période 1860-2010.Ce résultat est cohérent avec Liverpool (+1,2 ± 0,1 mm/an sur la période 1858-1997 [Woodworth, 1999a]) et avec les récents résultats suggérant que l’élévation du niveau marin sur les côtes atlantiques européennes est moins importante qu’au niveau mondial (+1,7 ± 0,3 mm/an sur la période 1870-2004 [Church & White, 2006]). / Global sea level rise, which is estimated at 17 ± 2 cm over the last century, does not reflect the differences of the sealevel evolution between places across the world. What is the situation along the Charente-Maritime French Atlanticcoast? Time series covering a period of at least 40-50 years are vital to establish reliable long-term trends of sealevel components: mean sea level, tidal constituents and meteorological effects. Many tide gauge data sets of the Charente-Maritime coast have recently been rediscovered in archives: La Rochelle-Vieux port (1775-1892), La Rochelle-La Pallice (1885-today), île d’Aix (1824-today), fort Enet (1859-1873), fort Boyard (1873-1909) and Cordouan (1812-1994). The aims of this thesis were firstly to inventory, to rescue and to digitize historical sea leveldata sets. Secondly, those data sets were put back together in order to construct continuous time series, which have been analysed and led to a better description of long-term sea level changes. In this way, three time series were constructed (La Rochelle: 1775-today; Aix-Enet-Boyard: 1824-today; and Cordouan: 1812-1994) and have been deeply examined to assess the construction validity and quality. From these new time series, we could estimate changes of sea level components. Thanks to this research work, we have been able to provide an inventory as exhaustive as possible, with detailed measurements of twenty five Charente-Maritime’s stations from 1775 to nowadays. All those data will be soon available on REFMAR (refmar.shom.fr), SONEL (www.sonel.org) and PSMSL (www.psmsl.org) websites. From those positive results, we have been able to reconstruct a more global time series (Pertuis d’Antioche) from the monthly mean sea levels of La Rochelle and Aix-Enet-Boyard. Among our results, we can high light that the mean sea level trend on Pertuis d’Antioche is estimated at +1.38 ± 0.08 mm/year, from 1860 to 2010. This result is consistent with Liverpool’s trend (+1.2 ± 0.1 mm/year from 1858 to 1997[Woodworth, 1999a]) and also with recent results suggesting that sea level rise along the European Atlantic coasts isslower than global sea level rise (+1.7 ± 0.3 mm/year from 1870 to 2004 [Church & White, 2006]).

Many Climate Scientists believe that global warming will produce more extreme weather events such as tropical storms, hurricanes, intense rainfall, and flooding. These events are considered to be the most catastrophic natural events for transportation systems especially in coastal areas. Due to the severe damage from storm surge and flooding. Evaluating the magnitude of possible storm surges and their impacts on transportation systems in coastal areas is fundamental to developing adaptation plans and impact assessments to mitigate the damage. This thesis focuses on existing transportation systems in the Georgia coastal area that could be affected by several storm surges. An existing storm surge model is used to estimate the storm surges and the surge heights based on the category, direction, and forward speed of a storm. The ground elevation of the ports, interstates, state roads, railroads, and the principal airports on the Georgia coast are identified through a GIS analysis using the national elevation data set. Having the storm surge elevation and the elevation of the existing infrastructure, a GIS study is performed to identify those parts of the transportation system that will be affected by each type of storm giving results such as the length or sections of transportation assets under or above the surge elevation. A literature review of storm surge, rising sea levels, and their impacts on coastal bridges, roads, airports, ports, and railroads is presented in the thesis. Also, a description of the software used to analyze and estimate the impacts of climate change on transportation systems is described.