As praias urbanizadas são ambientes complexos devido à interação da ocupação antropogênica e dos processos costeiros. A ocupação costeira vem se caracterizando por alteração e deterioração da paisagem, processo mais intenso em grandes cidades litorâneas, onde casas e edifícios são construídos nas proximidades imediatas da orla. O presente trabalho analisa a morfodinâmica e processo de sobrelavagem das praias de Santos e Itararé, duas praias urbanizadas com a presença de obras na orla. Foram realizados levantamentos topográficos nas praias e modelagem de ondas (Delft 3D - Wave) para toda a baía durante os anos de 2015 e 2016. Cenários de sobrelevaçãoonda e nível do mar foram estipulando para o cálculo da sobrelevaçãototal e assim conhecer as condições que levam a sobrelavagem. A baía de Santos encontra-se aberta para sul, expondo a linha de costa para a ação de frentes frias. A variabilidade do clima de ondas, derivada das mudanças das suas condições meteorológicas formadoras, pode alterar a morfologia da praia. Em Santos e São Vicente as ondas de sul e sudeste apresentam maiores alturas de onda e são mais frequentes no outono e inverno quando temos mais frentes frias na região. Os resultados indicam relação entre a incidência de ondas com maior força de onda (W/m), associadas a frentes frias, em trechos mais inclinados das praias com perda de volume. A variedade de incidência das ondas ao longo da praia estudada mostra um decréscimo na força de onda, sendo maior em Itararé e caindo em direção a Ponta da Praia, com a presença de picos altos na Ponta da Praia. Justificando porque este trecho sofre mais variação de volume e perda de sedimento fato que pode estar associado a dragagem do canal do porto de Santos. Em ambos os trechos com maior declividade e menor faixa de areia apresentaram maior sensibilidade à ação das ondas e também maior chance de sofrer sobrelavagem, de todo o arco praial da baía de Santos a porção leste de Santos se mostrou a mais propícia a sofrer inundação. / Urbanized beaches are more complex environments due to the interaction of anthropogenic occupation and coastal processes. Coastal occupation has been characterized by alteration and deterioration of the landscape, being more intense in large coastal cities, where houses and buildings are built in the immediate vicinity of the beach border being subject to potentially high risk of erosion. The present work analyzed the morphodynamics and overwashing of the beaches of Santos and Itararé, two urbanized beaches with the presence of anthropogenic constructions in the beach border. Topographic surveys on both beaches and wave modeling (Delft 3D - Wave) were carried out for the entire basin during the years of 2015 and 2016. Wave run-up and sea level scenarios were stipulated for the calculation of the total water level and so determined conditions that lead to overwashing. The bay of Santos is open to the South, exposing the coast line for the action of cold fronts. The variability of the wave climate, derived from the changes of its formative meteorological conditions, can alter the morphology of the beach. In Santos and São Vicente, South and Southeast waves have higher wave height and are more frequent in autumn and winter when we have more cold fronts in the region. The results indicate the direct relationship between the incidence of waves with higher wave force (W/m), associated with cold fronts, with loss of volume along the beaches. The variety of wave incidence along the studied beach shows a decrease in wave force, being higher in Itararé and falling towards Ponta da Praia, in the area protected by the rocky promontory. However in Ponta da Praia we see high values of wave force, justifying why this stretch suffers more volume variation and loss of sediment, that we belive happends because of Port Channel. In both stretches with greater slope and lower sand range showed greater sensitivity to the action of the waves and also greater chance of overwash, of all the praial arc of the Santos bay, the Eastern portion of Santos was the most propitious to suffer flooding.

As praias urbanizadas são ambientes complexos devido à interação da ocupação antropogênica e dos processos costeiros. A ocupação costeira vem se caracterizando por alteração e deterioração da paisagem, processo mais intenso em grandes cidades litorâneas, onde casas e edifícios são construídos nas proximidades imediatas da orla. O presente trabalho analisa a morfodinâmica e processo de sobrelavagem das praias de Santos e Itararé, duas praias urbanizadas com a presença de obras na orla. Foram realizados levantamentos topográficos nas praias e modelagem de ondas (Delft 3D - Wave) para toda a baía durante os anos de 2015 e 2016. Cenários de sobrelevaçãoonda e nível do mar foram estipulando para o cálculo da sobrelevaçãototal e assim conhecer as condições que levam a sobrelavagem. A baía de Santos encontra-se aberta para sul, expondo a linha de costa para a ação de frentes frias. A variabilidade do clima de ondas, derivada das mudanças das suas condições meteorológicas formadoras, pode alterar a morfologia da praia. Em Santos e São Vicente as ondas de sul e sudeste apresentam maiores alturas de onda e são mais frequentes no outono e inverno quando temos mais frentes frias na região. Os resultados indicam relação entre a incidência de ondas com maior força de onda (W/m), associadas a frentes frias, em trechos mais inclinados das praias com perda de volume. A variedade de incidência das ondas ao longo da praia estudada mostra um decréscimo na força de onda, sendo maior em Itararé e caindo em direção a Ponta da Praia, com a presença de picos altos na Ponta da Praia. Justificando porque este trecho sofre mais variação de volume e perda de sedimento fato que pode estar associado a dragagem do canal do porto de Santos. Em ambos os trechos com maior declividade e menor faixa de areia apresentaram maior sensibilidade à ação das ondas e também maior chance de sofrer sobrelavagem, de todo o arco praial da baía de Santos a porção leste de Santos se mostrou a mais propícia a sofrer inundação. / Urbanized beaches are more complex environments due to the interaction of anthropogenic occupation and coastal processes. Coastal occupation has been characterized by alteration and deterioration of the landscape, being more intense in large coastal cities, where houses and buildings are built in the immediate vicinity of the beach border being subject to potentially high risk of erosion. The present work analyzed the morphodynamics and overwashing of the beaches of Santos and Itararé, two urbanized beaches with the presence of anthropogenic constructions in the beach border. Topographic surveys on both beaches and wave modeling (Delft 3D - Wave) were carried out for the entire basin during the years of 2015 and 2016. Wave run-up and sea level scenarios were stipulated for the calculation of the total water level and so determined conditions that lead to overwashing. The bay of Santos is open to the South, exposing the coast line for the action of cold fronts. The variability of the wave climate, derived from the changes of its formative meteorological conditions, can alter the morphology of the beach. In Santos and São Vicente, South and Southeast waves have higher wave height and are more frequent in autumn and winter when we have more cold fronts in the region. The results indicate the direct relationship between the incidence of waves with higher wave force (W/m), associated with cold fronts, with loss of volume along the beaches. The variety of wave incidence along the studied beach shows a decrease in wave force, being higher in Itararé and falling towards Ponta da Praia, in the area protected by the rocky promontory. However in Ponta da Praia we see high values of wave force, justifying why this stretch suffers more volume variation and loss of sediment, that we belive happends because of Port Channel. In both stretches with greater slope and lower sand range showed greater sensitivity to the action of the waves and also greater chance of overwash, of all the praial arc of the Santos bay, the Eastern portion of Santos was the most propitious to suffer flooding.

An increase in the frequency and intensity of storm events is predicted by numerous climate researchers for the north of Europe. Not only this but also landuse change in form of clear-cutting can have an impact on the discharge of rivers and with that on road drainage structures. Extensive societal costs can be the consequences of blockage and underdimensioned structures. Hydrological models are powerful instruments that can be used to assess the future dimension requirements for road drainage structures especially in specifically vulnerable areas. In this thesis the hydrological model MIKE SHE was set up to study the discharge and water level at two pipe bridges and one culvert within the catchment of the river Hakerud in Västra Götaland, Sweden. Three scenarios were considered including a changing climate until 2050 and 2100 and a clear-cut scenario aiming to find out if the current design is sufficient for the future. This model can be used as an example model set-up for similar studies taking the recommendations of the experience gained in this thesis into consideration. For the Swedish Transport Administration further studies on this basis can contribute to decision making on the dimensioning of road drainage structures in the future to ensure a safe and robust infrastructural system.

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<p>Eutrophication from agricultural runoff is a global issue, and can often result in degradation and loss of aquatic habitat. The overall objective of this study is to gain a better understanding of the factors that influence variation in water chemistry of low-order streams in an agricultural watershed. The first chapter finds significant differences between the effects of livestock- vs and crop-based operations on water chemistry while modeling the relationship between independent landscape variables and major water-quality parameters in an agroecosystem. I also determine significant differences exist in dependent variables among seasons and are best described by the agriculturally relevant calendar (ARC). In Chapter 2, I compared the effectiveness of discrete and continuous sampling programs for monitoring the impacts of cattle disturbances on water quality. I found that daily total phosphorus (TP) concentrations (integrated sample taken every 6 hours) were not significantly correlated with precipitation and were significantly lower than discrete water samples. Turbidity readings (recorded every half hour) showed spikes that corresponded with cattle hydration events and increased levels of nutrients through backwash. . In Chapter 3, I find a significant relationship between periphyton growth and the level of primary nutrients (TP, soluble reactive phosphorus, total-ammonia nitrogen). Thus, for low-order streams influenced by small family farms, acrylic rods may be an inexpensive indicator of excess limiting nutrients. In such environments stream length may be a stronger measure of streams than stream order since total nitrogen, TP and pH were significantly correlated with stream length.</p> / Master of Science (MSc)

Concentrations of dissolved organic carbon (DOC) measured within water bodies have been increasing on a global scale over the last two decades. Changes in temperature and rainfall have been shown to increase the production and export of DOC from catchments with peat soils in the UK (Freeman et al., 2001). However it is not clear whether increases in DOC concentrations are caused by production increases induced by temperature changes or by a greater incidence of high flows induced by rainfall changes. Increases in both temperature and rainfall have been predicted in Scotland over the next few decades (Kerr et al., 1999) which may further increase current DOC concentrations and exports. The implications of this include both a decrease in water quality and an increase in mobility of metals in upland water bodies. The overall aim of the thesis is to determine if the relationship between dissolved organic carbon (DOC) concentrations and discharge has changed over a 20 year period in small stream catchments in Scotland, in order to better understand the role of hydrology, in driving changes in DOC concentration. To achieve this streams draining two coniferous forest sites and one moorland site were monitored intensively between June 2004 and February 2006. Analysis of the relationship between DOC and discharge, within the catchments, identified the importance of the amount of precipitation falling on the catchment, antecedent precipitation and season, on the concentration of DOC that was measured within the stream. Models were then developed using variables to represent these drivers in terms of both the production (seasonal sine values and 14 day average temperatures) and movement (log of discharge (log Q), days since previous storm event and rising or falling stage) of DOC. In the Ochil Hills catchment, the best predictive model, used 4 hour average discharge and 1 day average 30cm soil temperatures (R2= 0.88). In the Duchray and Elrig catchments, the best predictive models produced used discharge and seasonal sine values; the strength of the model was greater in the Elrig (R2= 0.80) than the Duchray (R2= 0.48) catchment. The strength of the regression models produced highlighted the importance of precipitation in the movement of DOC to the stream and temperature variables representing production in the surrounding catchment. To determine if dissolved organic carbon (DOC) concentrations had changed within the three study catchments, since previous research was conducted at the same sites in the early 1980s and 1990s (Grieve, 1984a; Grieve, 1994), then regression analysis conducted in the previous research was repeated, so changes in the DOC and discharge relationship could be identified. Analysis of the Ochil Hills regression equations identified higher log of discharge and lower temperature and seasonal sine values in the present study (2004-06), when compared to the previous study (1982-83). This suggests that more DOC is now available for movement from the soil, and that the difference between winter and summer DOC production has decreased, potentially because of increasing temperatures. This would explain the limited increase in DOC concentration within the Ochil Hills stream. In the Duchray and Elrig streams, a large increase in DOC was identified at all discharges when all the models produced were compared between the two sampling periods (1989-90 and 2004-06). The increasing trend in DOC concentrations is too large to have been produced by change in temperature alone and it is suggested that the measured reduction in acidic deposition has resulted in the increased DOC concentrations measured in the Duchray and Elrig. The results from this research have identified that concentrations of DOC have increased in Scottish streams over the last 20 years and that the increases in DOC have been induced, potentially by temperature changes in climate. However, changes in temperature are not the only driver of this change as the reduction in acidic deposition is potentially more important, specifically in areas with base poor geology such as the Duchray and Elrig catchments.

Les changements globaux sont aujourd’hui une réalité et les activités humaines à l’origine de ces bouleversements tendent à augmenter avec par exemple l’utilisation toujours plus importante de produits chimiques. Les pollutions résultantes peuvent alors avoir un fort impact sur les écosystèmes, en particulier ceux d’eaux douces de surface.Cette thèse a d’abord montré au travers d’un échantillonnage à haute fréquence d’une rivière typiquement méditerranéenne (la Têt), lors d’un évènement pluvieux intense caractéristique, que des phénomènes de multicontaminations ont lieu avec la présence dans les eaux naturelles de sels nutritifs, éléments trace métalliques, pesticides et produits pharmaceutiques entre autres. Ces phénomènes de contaminations multiples sont principalement liés aux débordements du réseau urbain d’évacuation des eaux qui ont lieu au travers des débordements de déversoirs d’orage. Cette étude a également montré, grâce à l’utilisation de la nouvelle technique de séquençage haut-débit MiSeq, que les changements dans les diversités structurelles des communautés bactériennes aquatiques de la matière en suspension évoluent principalement en fonction de l’hydrodynamique de la rivière, les plus fortes dissimilarités entre les communautés s’observant lors du pic de débit. Les paramètres physico-chimiques environnementaux ont également un impact majeur sur la structure des communautés, ce qui pourrait amener suite à l’exploration des taxons bactériens associés à une dynamique de contaminations caractéristiques, à la découverte de biomarqueurs spécifiques de ces phénomènes. / Global changes cannot be ignored nowadays and human activities causing these disruptions tend to increase with, for example, the growing use of chemicals. The resulting pollution can then have a strong impact on ecosystems, in particular those of fresh surface waters.This thesis first showed through a high-frequency sampling of a typically Mediterranean river (the Têt River), during a characteristic intense rainy event, that multicontaminations occur with the presence in natural waters of nutrients, trace metals, pesticides and pharmaceuticals among others. These multicontamination phenomena are mainly related to the overflows of the sewage system that take place through storm overflows. This study has also shown, through the use of the new MiSeq high-throughput sequencing technique, that changes in the structural diversities of aquatic bacterial communities of suspended matter evolve mainly according to the hydrodynamics of the river, the strongest dissimilarities between the communities being observed during peak flow. The physico-chemical environmental parameters also have a major impact on the structure of communities, which could lead to the exploration of bacterial taxa associated with a characteristic contaminations dynamic, to the discovery of specific biomarkers of these phenomena.

No description available.