A pesquisa teve como objetivo compreender o papel dos rearranjos de drenagem à evolução do relevo e da drenagem na bacia hidrográfica do Rio Capivari, situada no reverso da Serra do Mar, em São Paulo-SP. Parte-se da hipótese de que esses fenômenos seriam responsáveis por inúmeras anomalias de drenagem observadas, como: inflexões em ângulos retos, padrões de drenagem anômalos, colos, rupturas em perfis longitudinais e subdimensionamento de cursos dágua em relação aos vales. Especial ênfase foi dada à inflexão do alto Rio Capivari, localizada na confluência com o Ribeirão Embura, possível remanescente de uma captura fluvial, o qual melhor preserva as evidências de um rearranjo em toda a bacia. Os principais fatores dos rearranjos de drenagem na área foram: o forte gradiente hipsométrico proporcionado pela Serra do Mar, a densa trama de foliações e fraturas presentes no embasamento geológico, movimentações tectônicas recentes e as oscilações paleoclimáticas do Quaternário tardio. Sob influência dessas forças, alguns tributários da drenagem litorânea teriam se aproveitado de sua vantagem erosiva frente aos rios de planalto, produzido uma marcha de erosão regressiva em direção ao interior, com interferências nos canais situados em níveis sucessivamente mais elevados. Com base nas propostas metodológicas de Small (1972), Bishop (1995), Zaprowski et al. (2002) e Oliveira (2003), buscou-se a identificação de elementos morfológicos e sedimentológicos sugestivos desses processos, por meio de: análise de Modelos Digitais do Terreno (MDE) por métodos geomorfométricos; observação de fotografias aéreas; trabalhos de campo para descrição e coleta de materiais sedimentológicos; análise granulométrica, morfoscópica e mineralógica de sedimentos fluviais; e datação de sedimentos fluviais por Luminescência Óptica Estimulada para se estimar a idade da captura do alto curso do Rio Capivari. Os dados apresentados corroboram a hipótese de que o alto curso desse rio sofreu uma captura há cerca de 8.000 anos, no máximo, e que diversos outros casos de rearranjos de drenagem, entre eles reversões de grandes sistemas fluviais, seriam responsáveis pelas anomalias de drenagem observadas no interior da bacia estudada. / The aim of this research was to understand the role of drainage rearrangements on the evolution of relief and drainage in the Capivari River basin, located on the reverse of Serra do Mar range, in the state of São Paulo, Brazil. It is assumed that these phenomena would be responsible for numerous drainage anomalies observed, such as: river inflections at right angles, anomalous drainage patterns, cols, knickpoints and river underfitting, considered as indicative for drainage rearrangements. Special emphasis will be given to the inflection of the Capivari River at the confluence with the Ribeirao Embura, a possible remnant of a stream capture, which best preserves the evidence of a rearrangement throughout the basin. The main factors of the drainage rearrangements in the area would be: the strong hypsometric gradient provided by Serra do Mar range, the set of foliations and fractures densely present in the geological basement, recent tectonic movements and climatic oscillations of the Quaternary. Under the influence of these forcings, some tributaries of the coastal drainage would have taken erosive advantage over the plateau upside rivers, producing a regressive erosion march towards the interior of the continent, leading to interferences in the river systems situated at successively higher levels. Based on the methodological proposals of Small (1972), Bishop (1995), Zaprowski et al. (2002) and Oliveira (2003), we seek the identification of morphological and sedimentological elements that are suggestive of these processes, by means of: Digital Elevation Models (DEM) analysis by geomorphometric methods; observation of aerial photographs; fieldwork for description and collection of sedimentological materials; granulometric, morphoscopic and mineralogical analysis of fluvial sediments; and dating of fluvial sediments by Optically Stimulated Luminescence to estimate the age of capture of the upper reaches of the Capivari River. The presented data corroborate the hypothesis that the high course of the Capivari river was captured at least 8,000 years ago and that several other cases of drainage rearrangements, including reversals of large river systems, would be responsible for the observed drainage anomalies.

La connaissance de la dynamique hydrosédimentaire des rivières avant et pendant l’installation des nombreux aménagements hydrauliques depuis l’Antiquité restaient très fragmentaire en Basse-Normandie et plus largement en Europe de l’Ouest. On savait encore peu de choses sur les processus d’érosion et de sédimentation qui se sont succédés au sein des rivières normandes au cours des deux derniers millénaires et la part des forçages anthropiques et climatiques qui ont influencé ces processus. L’objectif de la thèse est donc de comprendre et de mesurer la part des héritages dans le fonctionnement actuel des rivières afin de contribuer à leur gestion contemporaine. A cette fin, des recherches géomorphologiques et géoarchéologiques ont été menées dans plusieurs vallées bas-normandes. Ces études ont mis en évidence le poids des installations hydrauliques et en particulier le développement des moulins à eau dans la modification des chenaux d’écoulement mais aussi la construction des plaines alluviales. En effet, la structuration complète du cours d’eau depuis le Moyen Âge a fortement artificialisé les formes en plan et les pentes des cours d’eau et complètement cloisonné leur linéaire. Ces transformations ont favorisé la stabilité latérale des cours d’eau et la sédimentation limoneuse par débordement au sein des plaines alluviales. L’installation de moulins s’accompagne très souvent d’une simplification du tracé en plan de la rivière. Lors de l’équipement maximal des cours d’eau normands on trouvait un moulin tous les 2500 mètres de linéaires hydrographiques. Ces transformations signifient qu’une grande partie des cours actuels sont artificiels. En effet, ces aménagements et l’accélération de la sédimentation limoneuse depuis 1000 ans sont à l’origine de la mise en place d’un équilibre dynamique aboutissant aux formes hydrosédimentaires des rivières actuelles. L’abandon de la gestion des ouvrages hydrauliques et leur destruction au cours des cinquante dernières années viennent remettre en cause cet équilibre. / In Lower Normandy, knowledge of the hydrosedimentary dynamics of rivers before and during the installation of the numerous hydraulic installations since the Roman period remains very fragmentary. Little was known about the rates of erosion and sedimentation that have occurred over the last two millennia and how climatic and anthropogenic controls have influenced these processes. Thus, the challenge of this phD is to understand and measure the role of the inherited structures and operating in the current functioning of the rivers of Lower Normandy in order to help with their contemporary management. To provide answers, geomorphological and geoarchaeological researches has been carried out in several valleys. These studies make it possible to highlight the weight of the hydraulic installations and in particular the developments related to the mills in the setting up of floodplains. Indeed, the complete structuring and management of the watercourse since the Middle Ages artificialized riverbed forms and slopes, and partitioned rivers favoring lateral stability and overflow sedimentation in the floodplain conducting in the development of completely regulated rivers. The installation of mills is accompanied locally by a simplification of the river course. At the acme of the equipment there was a mill every 2,500 meters along the rivers of Lower Normandy. These transformations mean that a large part of current courses are artificial. These structures and the increase of the overbank silt sedimentation for 1000 years are at the origin of the establishment of a dynamic equilibrium resulting in the hydrosedimentary forms of the present rivers which are largely inherited. The abandonment of the management of the hydraulic structures and their destruction during the last fifty years comes to question this balance.

Made available in DSpace on 2014-06-11T19:26:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-03Bitstream added on 2014-06-13T20:14:49Z : No. of bitstreams: 1 santos_vc_me_rcla.pdf: 1357104 bytes, checksum: 93f8d2931c8ea5facacb9de9abe21ee3 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O rio Paraná, em seu trecho natural, possui padrão multicanal caracterizado por canais secundários de diferentes ordens, separando diversas ilhas e barras fluviais. As barras fluviais são formas semi-submersas associadas à disponibilidade de sedimentos e a um dinamismo temporal cujas dimensões são controladas pelo fluxo e pela profundidade. Neste estudo, pretende-se compreender os processos que promovem a formação, desenvolvimento e movimentação de uma barra de soldamento situada junto à ilha Santa Rosa, no rio Paraná, município de Porto Rico - PR. Para alcançar os objetivos propostos, foram realizados levantamentos de parâmetros hidráulicos, morfométricos e granulométricos. Nos dados levantados dos parâmetros hidráulicos, verificou-se que a presença da ilha Santa Rosa, juntamente com barra fluvial, divide o canal em dois setores de dinâmica hidráulica e sedimentar distintas. O canal principal conduz a maior parcela da vazão, é mais energético, enquanto o canal secundário apresenta valores inferiores nestes dois parâmetros. A separação do fluxo também acarreta na formação de correntes divergentes à direção principal do canal, favorecendo a diminuição da velocidade e, consequentemente, a deposição de sedimentos no entorno da ilha Santa Rosa. Averiguou-se que a morfologia da barra está diretamente vinculada às flutuações de vazão do rio Paraná: em período de águas altas há maior retrabalhamento da forma, já no período de águas médias, esta se preservou parcialmente, inclusive com afloramento em parte. Quanto aos sedimentos, as partículas de diâmetro fino distribuem-se em locais de maior velocidade de fluxo e profundidade (talvegue) em ambos os períodos analisados As partículas de diâmetro médio a grosso encontram-se no período de águas altas distribuídas pela área estudada; já no período de águas médias, estes sedimentos... / The Paraná River, in its natural stretch, has a multichannel pattern characterized by secondary channels of different orders, which separates several islands and bars. The bars are forms semi-submerged associated with the availability of sediment and a temporal dynamic, whose dimensions are controlled by the flow and depth. This study intends to understand the processes which promote formation, development and movement of the annexation bar associated to the Santa Rosa Island, located on Paraná River, near to Porto Rico - PR. To achieve the proposed aims, surveys were carried out in hydraulic, morphometric and granulometric parameters. In the data hydraulic parameters survey it was found that the presence of Santa Rosa Island along with bar divides the river channel in two sectors of distinct dynamic hydraulic and sediment. The main channel leads to a higher portion of the flow, it is more energetic, while the secondary channel has lower values in these two parameters. The separation of the flow also causes the formation of divergent currents towards the main channel, favoring the decrease in velocity and consequent deposition of sediments near to Santa Rosa Island. It was found that the morphology of the bar is directly linked to fluctuations in the flow of the Paraná River, during periods of high water there is more reworking, since in this average water period partially preserved its shape, emerging in part. As for sediment, the fine diameter particles are distributed in areas of higher flow velocity and depth (thalweg) in both analyzed periods. From medium to coarse diameter particles are, in the high-water period, distributed in the studied area, although in the average water period these sediments are located in low flow velocity and depth (Bar and Secondary Channel). Specific stream power and shields parameter values are larger in the main channel in both periods, indicating... (Complete abstract click electronic access below)

A pesquisa teve como objetivo compreender o papel dos rearranjos de drenagem à evolução do relevo e da drenagem na bacia hidrográfica do Rio Capivari, situada no reverso da Serra do Mar, em São Paulo-SP. Parte-se da hipótese de que esses fenômenos seriam responsáveis por inúmeras anomalias de drenagem observadas, como: inflexões em ângulos retos, padrões de drenagem anômalos, colos, rupturas em perfis longitudinais e subdimensionamento de cursos dágua em relação aos vales. Especial ênfase foi dada à inflexão do alto Rio Capivari, localizada na confluência com o Ribeirão Embura, possível remanescente de uma captura fluvial, o qual melhor preserva as evidências de um rearranjo em toda a bacia. Os principais fatores dos rearranjos de drenagem na área foram: o forte gradiente hipsométrico proporcionado pela Serra do Mar, a densa trama de foliações e fraturas presentes no embasamento geológico, movimentações tectônicas recentes e as oscilações paleoclimáticas do Quaternário tardio. Sob influência dessas forças, alguns tributários da drenagem litorânea teriam se aproveitado de sua vantagem erosiva frente aos rios de planalto, produzido uma marcha de erosão regressiva em direção ao interior, com interferências nos canais situados em níveis sucessivamente mais elevados. Com base nas propostas metodológicas de Small (1972), Bishop (1995), Zaprowski et al. (2002) e Oliveira (2003), buscou-se a identificação de elementos morfológicos e sedimentológicos sugestivos desses processos, por meio de: análise de Modelos Digitais do Terreno (MDE) por métodos geomorfométricos; observação de fotografias aéreas; trabalhos de campo para descrição e coleta de materiais sedimentológicos; análise granulométrica, morfoscópica e mineralógica de sedimentos fluviais; e datação de sedimentos fluviais por Luminescência Óptica Estimulada para se estimar a idade da captura do alto curso do Rio Capivari. Os dados apresentados corroboram a hipótese de que o alto curso desse rio sofreu uma captura há cerca de 8.000 anos, no máximo, e que diversos outros casos de rearranjos de drenagem, entre eles reversões de grandes sistemas fluviais, seriam responsáveis pelas anomalias de drenagem observadas no interior da bacia estudada. / The aim of this research was to understand the role of drainage rearrangements on the evolution of relief and drainage in the Capivari River basin, located on the reverse of Serra do Mar range, in the state of São Paulo, Brazil. It is assumed that these phenomena would be responsible for numerous drainage anomalies observed, such as: river inflections at right angles, anomalous drainage patterns, cols, knickpoints and river underfitting, considered as indicative for drainage rearrangements. Special emphasis will be given to the inflection of the Capivari River at the confluence with the Ribeirao Embura, a possible remnant of a stream capture, which best preserves the evidence of a rearrangement throughout the basin. The main factors of the drainage rearrangements in the area would be: the strong hypsometric gradient provided by Serra do Mar range, the set of foliations and fractures densely present in the geological basement, recent tectonic movements and climatic oscillations of the Quaternary. Under the influence of these forcings, some tributaries of the coastal drainage would have taken erosive advantage over the plateau upside rivers, producing a regressive erosion march towards the interior of the continent, leading to interferences in the river systems situated at successively higher levels. Based on the methodological proposals of Small (1972), Bishop (1995), Zaprowski et al. (2002) and Oliveira (2003), we seek the identification of morphological and sedimentological elements that are suggestive of these processes, by means of: Digital Elevation Models (DEM) analysis by geomorphometric methods; observation of aerial photographs; fieldwork for description and collection of sedimentological materials; granulometric, morphoscopic and mineralogical analysis of fluvial sediments; and dating of fluvial sediments by Optically Stimulated Luminescence to estimate the age of capture of the upper reaches of the Capivari River. The presented data corroborate the hypothesis that the high course of the Capivari river was captured at least 8,000 years ago and that several other cases of drainage rearrangements, including reversals of large river systems, would be responsible for the observed drainage anomalies.

O estudo de bacias hidrográficas no meio tropical úmido, tem adquirido grande importância nas últimas décadas, devido a crescente demanda por planejamento de recursos hídricos. Entretanto, muitos desses trabalhos têm confundido o conceito de bacias hidrográficas, acreditando ser esta, uma mera rede de canais interconectados que formam a hidrografia dos terrenos, portanto, tomando-a como simples unidade cartográfica de estudo. Este fato tem banalizado em muito o uso de conceitos relacionados aos estudos de bacias, provocando sérios equívocos nas produções acadêmicas atuais. Partindo do princípio de que as bacias hidrográficas são espaços territoriais de circulação vertical e horizontal dágua, tendo a rede interconectada de canais, como um dos seus principais elementos, que escolhemos a bacia hidrográfica do Rio Benevente para estudo da relação entre a dinâmica fluvial desta e os seus condicionantes estruturais e morfológicos. Fundamentado no método da associação e indeterminação geomorfológica de Leopold e Langbein (1970), e, através de informações oriundas dos procedimentos técnico-operacionais de compartimentação geomorfológica e compilação de dados de parâmetros hidrográficos, foi possível descobrir que os sub-sistemas de drenagem que compõem a hidrografia total da bacia, evoluem condicionados por litoestruturas cristalinas e tectônicas do proterozóico, portanto, de organização antiga, e, que, aparentemente, demonstram não sofrer reativações modernas, a ponto de intervir na evolução dos sub-compartimentos de relevo regionais e na evolução hidrográfica da rede de canais. Chega-se desta forma, à conclusão de que os processos de encaixamento da drenagem, capturas fluviais, seccionamento de litoestruturas, gênese de knickpoints e evolução dos perfis longitudinais fluviais estão associados à dinâmica de processos geomórficos diferenciais, sob litoestruturas de forte natureza anisotrópica e complexa organização geotectônica. Fato que responde pela diversidade de sub-compartimentos de relevo e configuração evolutiva dos sistemas fluviais de dinâmicas diferenciais. / The study of watersheds in the humid tropical environment, has acquired great importance in recent decades due to growing demand for water resources planning. However, many studies have confused the concept of watersheds, believing that this was simply a network of interconnected channels that form the hydrography of the land, thus making it as simple cartographic unit of study. This commonplace is the use of concepts related to the studies of basins, causing serious confusion in the current academic productions. Assuming that the basins are territorial spaces of vertical and horizontal movement of water, the interconnected network of channels, as one of its main elements, we chose the basin of Rio Benevente to study the relationship between the dynamics of this river and its structural and morphological constraints. Based on the method of the Association and indeterminacy in geomorphologic Leopold and Langbein (1970), and through information from the technical and operational procedures of geomorphological partitioning and compilation of data from hydrographic parameters, could find that the sub-drainage systems that make up the total of the hydrographic basin, driven by evolving litoestruturas crystal and the tectonic proterozóico, therefore, the old organization, and that, apparently, show not suffer reactivations modern as to intervene in the evolution of sub-compartments of regional importance and the evolution of the network of river channels. Enough is thus concluded that the processes to fit the drainage, catch river, sectioning of litoestruturas, gênesis of knickpoints and evolution of longitudinal river profiles are associated with the dynamic of geomorphic processes differential,under litoestruturas of strong anisotropic nature and complex organization geotectônica. Fact responsible for the diversity of sub-compartments of important configuration and evolutionary dynamics of river systems of differential.

O estudo da geodiversidade vem sendo desenvolvido desde a década de 1990 e visa o conhecimento, descrição e conservação do patrimônio natural, através da avaliação de aspectos geológicos (minerais, rochas e fósseis), geomorfológicos (formas de relevo, processos) e pedológicos. A presente pesquisa buscou demonstrar e avaliar o potencial de utilização de variáveis da geomorfologia fluvial como indicadores de geodiversidade, considerando a subtilização deste tipo de indicador em estudos ambientais no Brasil. Essa subtilização coloca-se especialmente para a região amazônica, onde o ambiente fluvial tem grande relevância, seja nos aspectos ambientais, culturais estéticos ou científicos. O objetivo central da tese é a caracterização morfológica e análise, por amostragem, de padrões de canais fluviais e de outros parâmetros da morfologia fluvial na Bacia Hidrográfica do Rio Xingu, a fim de demonstrar a relevância desta variável para a avaliação da geodiversidade na Amazônia. Apesar de ainda ser, em grande parte, protegida por Unidades de Conservação e por Terras Indígenas, a Bacia Hidrográfica do Xingu sofre graves pressões antrópicas, ocasionadas principalmente pela monocultura de soja, nas áreas de cabeceiras, e pela construção da Usina Belo Monte na chamada Volta Grande do Xingu, próxima à sede do município de Altamira- PA. A pesquisa foi desenvolvida em duas escalas. Na de maior detalhe (1:150.000), foram realizados mapeamentos da morfologia fluvial para 23 áreas selecionadas como representativas da diversidade de padrões de canais fluviais na bacia hidrográfica considerada. Essa caracterização comprovou a grande diversidade de padrões de canais fluviais na área de estudo, demonstrando a pertinência desse parâmetro como indicativo de geodiversidade, e servindo também como base para a inserção da variável mudanças de padrão de canais fluviais na metodologia de mapeamento dos índices de geodiversidade da Bacia Hidrográfica do Xingu. Na escala de menor detalhe, foi aplicado um método de quantificação da geodiversidade, em toda a Bacia Hidrográfica, baseado na mensuração e integração dos elementos abióticos espacializados em mapas temáticos em escalas que variam de 1:250.000 a 1:1.000.000, com auxílio de um grid da articulação sistemática 1:25.000. Nesta escala foi realizada, também, uma correlação entre os índices de geodiversidade e os índices de biodiversidade, inferidos pelo XI mapeamento da vegetação em escala 1:250.000 (IBGE, 2000c). As principais contribuições da pesquisa foram o enriquecimento de bases para o estudo de grandes rios amazônicos e a aplicação de um método de mapeamento dos índices de geodiversidade, que poderá servir como instrumento para o planejamento ambiental, especialmente na definição de áreas prioritárias para conservação na região amazônica. / The study of geodiversity has been developed since the 1990s and aims the knowledge, description and conservation of natural heritage, through the evaluation of geological (minerals, rocks and fossils), geomorphological (landforms, processes) and pedological aspects. This research has intended to demonstrate and evaluate the potential use of fluvial geomorphological variables as geodiversity indicators, in view of the underutilization of this kind of indicator in environmental studies in Brazil. This underutilization is a critical issue for the Amazon region, where fluvial environments have great relevance on diverse aspects (environmental, cultural, aesthetic and scientific). The central aim of the thesis is the morphological characterization and analysis of river channel patterns and other parameters of fluvial morphology in sampling areas in the Xingu River Basin, in order to demonstrate the relevance of these parameters for the assessment of geodiversity in the Amazon. Although still largely preserved by conservation units and indigenous lands, the Xingu Basin suffers severe anthropogenic pressures, mainly caused by soy monocultures in headwater areas and by the construction of the Belo Monte Dam in the \"Volta Grande do Xingu\", near the town of Altamira, in the state of Pará. This research was conducted at two different spatial scales. On a more detailed scale (1:150,000), maps of fluvial morphology were made for 23 selected areas, which were considered representative of the diversity of river channel patterns in the drainage basin. This characterization proved the great diversity of river channel patterns in the study area, demonstrating the relevance of this parameter as an indicator of geodiversity. Such a characterization was also useful as a basis for the inclusion of the variable \"change in channel pattern\" in the mapping methodology of the geodiversity indexes in the Xingu Drainage Basin. On a less detailed scale, a method to quantify the geodiversity was applied to the entire drainage basin, based on the measurement and integration of abiotic elements, spatially distributed on thematic maps with scales ranging from 1:250,000 to 1:1,000,000, with the aid of a systematic articulation grid 1:25,000. On this scale it was also performed a correlation between the geodiversity and the biodiversity indexes, the latter inferred by vegetation mapping on scale 1:250,000 (IBGE, 2000c). XIII The main contributions of this research are the enrichment of the knowledge basis about large Amazonian rivers, as well as the application of a method for mapping the geodiversity indexes, which can be useful as a tool for environmental planning, particularly in defining priority areas for conservation in the Amazon region.

This work have quantitatively determine the catchment variables controlling the sinuosity transition of non-valley constrained DFS channels in Alaska, Himalaya and the Andes. Results from the characterisation of channel sinuosity were used through regression analyses to determine the catchment and channel bed parameters controlling reach sinuosity trend and transition of fluvial channel planforms in order to infer a control on the heterogeneity of DFS in the rock record. The catchment approach used was necessary because the studied fluvial systems are associated with DFS (which are regarded as larger forms of alluvial fans) and catchment based approach have been used to investigate controls on alluvial fan morphology. In addition, catchment based investigations are rare in the analyses of the discriminant functions that are considered as controlling factors on channel sinuosity and planform employed previously in the tributary systems. Two distinct channel types were found through the characterisation of 553 reaches of fluvial channels in 3 different modern continental sedimentary basins; channels with no transition in sinuosity/planform (group 1), and channels with transition in sinuosity/planform (group 2) Among the channel bed and catchment quantitative variables investigated in this work, catchment area is the only parameter that shows a general relationship with the channel distance from the apex to the transition point in channel sinuosity through the overall regression results. The result shows that the bigger the catchment area the longer the transition point which is related to a higher water and sediment discharge. Thus, the point at which the channel sinuosity transition will occur can be predicted from the catchment area through the regression equation [y=0.0017x + 28] of the overall linear regression line, where x is the catchment area and y is the channel distance from the apex to the point of transition in channel sinuosity. As the studied channels are associated with DFS, this relation also reflects the prediction of the transition point in the DFS fluvial styles in the rock record. Overall regression analysis results show statistically poor results for the relationship between catchment elevation, catchment slope, channel bed elevation, channel bed slope and either the channel sinuosity or the sinuosity transition. However, in all the three study areas, the majority of the datasets show a trend with the catchment area/sinuosity transition relationship. Additionally, the study area with mainly the biggest catchments (longer channel sinuosity transition) is associated with the highest catchment slope, lowest channel bed elevation and more anabranching channels. Also, the study area with mainly the smallest catchments (shorter channel sinuosity transition) is associated with lower catchment slope, higher channel bed elevation and fewer anabranching channels. This suggests that the higher water and sediment discharge may be related to the steeper slopes and the anabranching channels may reflect the lower channel bed elevation. However, deviations obeserved in the overall regression result in the three study areas are attributed to the differences in the climatic, geologic and tectonic factors in the 3 settings. Although, the differences in these study areas have been shown, nevertheless the interpretations cannot be substantiated in this work with the available data. Thus, there is need for further research to prove any conclusive relationship between these factors and hence remains an issue of debate. In conclusion, this work shows that catchment area is an important controlling parameter on the transition in channel sinuosity of non-valley constrained DFS channels and consequently reflects a a control on the transition in spatial variations of the associated DFS in the rock record.

As fluvial, riparian and floodplain ecosystem functions are recognised for their role supporting fisheries and ecological values, recovery of streamside vegetation is increasingly important in river 'restoration'. Fluvial geomorphology and hydraulic engineering do not yet account well for the role of vegetation in fluvial processes. This research addresses the need for greater understanding of woody riparian vegetation influences on the hydraulics of overbank flow and floodplains sedimentation. Original hypotheses, research design, and data collection were generated by the student to address this gap in knowledge. A soil bioengineering design was constructed on the Mattole River, California, to revegetate the floodplain for better fish rearing habitat. Field data collection was carried out on this unregulated river for two flood events. The sediment samples resulting from a 1.25-year flow permitted the field testing of an hydraulic flume model of vegetation trapping efficiency. From velocity profiles measured during a I5-year storm event, the bed shear stress reduction caused by the vegetation was computed to be approximately 70-90%. A survey conducted in the UK and internationally evaluated from literature, hydraulic researchers and practitioners of river revegetation, the extent of and gaps in knowledge with regard to river bank stabilisation using live vegetation. A flume flow visualisation study simulated the hydraulic behaviour observed on the Mattole floodplain, which enabled characterisation of flow behaviour through a porous filter medium. Results of this research indicate that flexible woody stems have a profound 'calming' effect on overbank flow. These effects are propagated in the downstream direction at least five and as much as ten times the width of the baffle, much further than previously indicated. This research suggests that flexible vegetation is extremely effective in trapping fine (clay) sediments, contrary to general understanding and of importance for fish habitat. For hydraulic reasons, constructed zones of shrubs, such as the siltation baffle, could be spaced further apart than current design practise indicates.

Wind erosion and associated dust emissions play a fundamental role in many ecological processes, yet most ecological studies do not explicitly consider dust-driven processes despite the growing body of evidence suggesting that wind erosion is a key driver of land surface dynamics and many other environmentally relevant processes such as desertification. This study provides explicit support for a pervasive underlying but untested desertification hypothesis by showing that at the vegetation patch scale shrubs are significantly more efficient at capturing wind-blown sediment and other resources such as nutrients than grasses and that this difference is amplified following disturbance. At the landscape scale, the spacing and shape of woody plants were found to be a major determinant of dryland aeolian sediment transport processes in grasslands, shrublands, woodlands and forests, particularly following disturbance. This study also found that disturbance such as fire can have a significant influence on background dust emissions, which can have important consequences for many basic ecological and hydrological processes. Potential interactions between aeolian and fluvial processes were also evaluated in this study, and a new conceptual framework was developed that highlights important differences and similarities between the two processes as a function of scale-dependencies, mean annual precipitation, and disturbance. This study also explicitly evaluates the effect of climatic extremes and alternate land management practices on the absolute and relative magnitudes of wind and water erosion. Notably, results indicate that wet/dry climatic extremes and grazing can increase the wind-to-water erosion ratio, whereas burning disproportionally increases water erosion relative to wind erosion.

A three part investigation into the effects of riparian reforestation on small streams demonstrated the timing, nature, and processes of morphologic change. First, measurements of two small streams in northeastern Vermont collected in 1966 and 2004 – 2005 documented considerable change in channel width following a period of passive reforestation. Channel widths of several tributaries to Sleepers River were measured in 1966 when the area had more non-forested riparian vegetation than today. A longitudinal survey in 2004 of two of these tributaries, followed by detailed measurements at specific reaches in 2005, provided information on channel size, large woody debris (LWD), and riparian vegetation. Reforested reaches have widened and incised markedly since 1966. Reaches with the oldest forest were widest for a given drainage area, and the non-forested reaches were substantially narrower. A conceptual model was developed that describes a multi-phase process of incision, widening, and recovery following riparian reforestation of non-forested areas. Second, a fixed-bed hydraulic model of one of the streams was developed to evaluate the impact of forested riparian vegetation on near-bank turbulence during overbank flows. Flume experiments with kinematic similitude and a 1:5 scale represented half a channel and its floodplain, mimicking the size of a non-forested reach. Two types of vegetation were simulated: non-forested, with synthetic grass carpet; and forested, where wooden dowels were added. Three-dimensional velocities were measured with an acoustic Doppler velocimeter. Velocities, turbulent kinetic energy (TKE), and Reynolds shear stress showed significant differences between forested and non-forested runs. Forested runs exhibited a narrow band of high TKE in the near-bank region that was roughly two times greater than in non-forested runs. Hydraulic characteristics of forested runs appear to create an environment with higher erosion potential, thereby indicating a possible driving mechanism for channel widening in reforesting stream reaches. Third, Light Detection and Ranging (LiDAR) data from Chittenden County were analyzed to develop a method capable of classifying riparian buffers into broad classes according to forest type and age. The geospatial characteristics of the LiDAR data in forested areas were explored using semivariogram analysis, and LiDAR-based metrics were derived in a geographic information system (GIS) to quantify vegetation height and variance. The LiDAR-based metrics were then used in two discriminant analysis procedures that distinguished: 1) forest type as deciduous or coniferous; and 2) forest age in four age classes. With the resulting linear discriminant functions, a GIS-based classification method was developed. The classification method was highly successful at determining forest type but only moderately successful at determining forest age.