The Guará Formation (Upper Jurassic) crops out in the western portion of Rio Grande do Sul along a track with north-south orientation, of which the northern part essentially consists of fluvial deposits with paleocurrent to southwest. Despite the existence of outcrops with good vertical exposure and high lateral continuity, had not yet been carried out detailed studies of fluvial architecture of this unit. Through facies analysis, with vertical logs and lateral sections data, 9 lithofacies composing 8 architectural elements were described and interpreted. These elements are grouped in sandstone bodies of two fluvial styles: (1) Deep perennial braided rivers – composed by simple and composed downstream-accretion elements, small and large-sized hollows, trough cross-stratified sets and overbank sand and fine facies – and (2) Poorly channelized ephemeral braided rivers - characterized by horizontally stratified sandstones and trough cross-stratified sets. Two or more sandstone bodies of same style amalgamate into 10 to 15 m packages representing time intervals with the domain of a river style. These packages alternate vertically separated by hundreds of meters lateral extent surfaces, reflecting intervals with larger and more continuous water discharge (sandstone bodies of deep perennial rivers) or with high energy episodic discharge (with sandstone bodies of poorly channelized ephemeral rivers). The river systems of the proximal portion of the Guará Formation reflects low frequency discharge variations, controlled by the climate. / A Formação Guará (Jurássico Superior) aflora na porção oeste do Rio Grande do Sul ao longo de uma faixa com orientação norte-sul, sendo a sua porção setentrional constituída essencialmente por depósitos fluviais com paleocorrente para sudoeste. Apesar da existência de afloramentos com boa exposição vertical e uma alta continuidade lateral, não haviam sido realizados até o presente momento estudos detalhados da arquitetura fluvial desta unidade. Por meio da análise de fácies, com a elaboração de perfis verticais e seções laterais, foram descritos e interpretados 9 litofácies que compõem 8 elementos arquiteturais. Estes elementos se agrupam em corpos arenosos de dois estilos fluviais: (1) Rios entrelaçados perenes profundos – compostos por elementos de acresção frontal simples e compostas, hollows de pequeno e grande porte, sets isolados com estratificações cruzadas e fácies arenosas e finas externas aos canais – e (2) Rios entrelaçados efêmeros fracamente canalizados – caracterizados por arenitos horizontalmente estratificados e sets isolados com estratificações cruzadas. Dois ou mais corpos arenosos de mesmo estilo se amalgamam em pacotes de 10 a 15 m que representam intervalos de tempo com o domínio de um estilo fluvial. Estes pacotes se alternam verticalmente separados por superfícies de centenas de metros de extensão lateral, refletindo intervalos com descarga aquosa maior e mais contínua (com corpos arenosos de rios perenes e profundos) ou com descarga episódica e de alta energia (com corpos arenosos de rios efêmeros fracamente canalizados). Os sistemas fluviais da porção proximal da Formação Guará refletem variações de descarga de baixa frequência, de controle climático.

Esta Tese traz reflexões sobre processos de produção audiovisual, defendendo a ideia de que essa produção organizada por professores em formação, em relação dialógica com o contexto no qual estão inseridos, interligando as imagens a diferentes aspectos, poderia levar os sujeitos envolvidos nos processos de ensino e aprendizagem ao reconhecimento do valor coletivo dessas práticas. O enfoque principal são os processos de produção audiovisual de professores em formação em Arte, delimitado neste estudo pelo contexto das tramas ecológicas, como um contexto propício a levar à instauração de diálogos, ampliação de campos de referência e produção de sentidos. A interação com as mídias digitais, disponibilizadas no campo educacional, surgem como ferramentas na construção do conhecimento que possibilitam reflexões sobre os processos éticos, estéticos e novos possíveis. O pensamento complexo, possibilitado por um olhar que dialoga com o contexto em que se está inserido e pela interligação de saberes como proposto por Morin, permitiu identificar processos de produção audiovisual, possibilitados por modos de organização e estratégias, através de interações com o meio e com atores sociais, caracterizados por retroações e recursividade que levam à interligação de diferentes conhecimentos. Para análise desses processos foi considerado o dialogismo de Bakthin que gerou os conceitos de polifonia, exotopia e cronotopia, que evidenciam aspectos das várias vozes, tempo e espaço da relação dialógica e atribuição de sentidos à obra criada/observada. A metodologia dessa análise de processos de produção audiovisual dos sujeitos é qualitativa e desenvolveu-se em uma abordagem de pesquisaparticipante, sugerida por Brandão e Borges (2007), que levam em consideração o conhecer, o pensar e o intervir, a exploração da comunidade, a identificação das necessidades básicas e a elaboração de estratégia educativa. Foi considerado ainda a Pedagogia da Autonomia de Freire (2002), no que se refere à escuta das narrativas dos participantes sobre suas experiências cotidianas, entendidas neste estudo, como fator preponderante à pesquisa. Dessa forma, os processos analisados dizem respeito ao resultado de diferentes atividades audiovisuais vivenciadas por professores em formação em Arte e artesãos, produtores de tramas ecológicas ou objetos em fibras vegetais, com diferentes faixas etárias, e restringem-se especificamente aos registros fotográficos e videográficos sobre o processo artesanal desses objetos, interrelacionados ou não aos aspectos culturais e educacionais que envolvem esse fazer. Esses resultados apontam para a importância do desenvolvimento de um olhar dialógico, possibilitado pela interação com as mídias de seu tempo na construção do conhecimento. / This dissertation reflects on audiovisual production processes, defending the idea that this production organized by teachersing training, on a dialogic relation to with context in which they are inserted, linking images to different aspects, could lead the individuals involved in teaching and learning processes to recognize the collective value of these practices. The main focus are the audiovisual production processes of teachers training in art, defined in this study by the context of ecological braided straw, as an enabling environment for the establishment of dialogue, expansion of reference fields and production of meanings as a context conducive to lead to the establishment of dialogue, expansion of reference fields and production of meanings. The interaction with digital media, available in the educational field, appear as tools in the construction of knowledge ethical, aesthetic and possible new processes. Complex thinking, made possible by a look that speaks to the context in which it is inserted and the interconnection of knowledge, as proposed by Morin, identified audiovisual production processes, possible by organizational methods and strategies, through interactions with the environment and with social actors characterized by retroactions and recursion that lead to the interconnection of different knowledge. The analysis of these processes were based on Bakhtin's dialogism and the concepts of polyphony, exotopy and chronotope with the evidence of various voices, time and space of dialogical relationship and attribution of meaning on the work done/observed. The methodology of this analysis of audiovisual production processes of the subject is qualitative and has developed into a research-participant approach, suggested by Brandão and Borges (2007), which take into account the knowledge, thought and action, the exploitation of community, identification of basic needs and the development of educational strategy. It was still considered the Pedagogy of Autonomy Freire (2002), with regard to listening to the narratives of the participants about their everyday experiences, understood in this study as a major factor research. Thus, the processes analyzed concern the result of different audiovisual activities experienced by teachers in training in Art and artisans, producers of ecological braided straw or objects in vegetable fibers, different age groups, and they are limited specifically to photographic records and videographic on the handmade process of these objects, inter-related or not to the cultural and educational aspects involved in this action. These results point to the importance of developing a dialogical look, made possible by the interaction with the media of their time in the construction of knowledge.

Pre-vegetation alluvium is unique; at the present day, plants affect multiple aspects of river functioning and deposition and so those rivers that operated before the evolution of land plants largely lack modern sedimentological analogue. However, such rivers were the norm for the first 90% of Earth history and so a better understanding of their sedimentary product enables insight into both the fundamental underlying mechanisms of river behaviour and the ways in which fluvial processes operated on ancient Earth and other rocky planets. This study presents five original fieldwork based case studies and an analysis of a holistic database of all of Earth’s pre-vegetation alluvium. Together these research strands offer perspectives on the sedimentological characteristics and stratigraphic trends of pre-vegetation alluvium and the behaviour and functioning of pre-vegetation rivers. Results show that, in pre-vegetation alluvial settings: 1) a variety of fluvial styles are represented, but diminished in comparison with syn-vegetation alluvium; 2) ‘sheet-braided’ architectures are common but may record a variety of fluvial planforms; 3) meandering planforms were less frequent, particularly in small- to moderate-sized river systems; 4) mudrock is on average 1.4 orders of magnitude less common than it is in syn-vegetation alluvium; and 5) microbial matgrounds were present, but had negligible effect on preserved architecture and facies. This thesis demonstrates that whilst the physical laws governing fluvial fluid-sediment interaction have not changed, the theatre in which they operated irrevocably evolved with the greening of the continents.

Les mécanismes complexes qui régissent la morphologie des rivières en tresses et l'interaction avec le tri granulométrique restent encore à approfondir. Cette thèse s'articule autour de trois thèmes : l'étude de la déstabilisation d'un système en tresses puis sa mise à l'équilibre, l'interaction de la morphologie avec le tri granulométrique et enfin la prédiction du transport solide. Pour cela, nous avons étudié 3 modélisations de différents systèmes alluviaux : des bancs alternés en granulométrie étendue (durée 100h), un système en tresses en granulométrie uniforme (durée 385h) et enfin un système en granulométrie étendue (durée 435h). Chaque modèle de tresses a subi plusieurs changements de conditions d'alimentation. Il ressort que seul un paramètre, la surface du lit situé au delà de la pente moyenne, pourrait être un bon candidat pour comparer l'état d'équilibre (érosion ou exhaussement) de différents systèmes. Pour une étude d'un site donnée, les paramètres classiques comme la pente ou le Bed Relief Index (BRI) sont tout aussi pertinents. Le tri granulométrique sur les systèmes divaguants se manifeste de plusieurs façons : il est à l'origine de la migration du chenal principal et participe activement à la formation de patchs sédimentaires, catalyseurs de l'émergence des bancs. Les lobes sédimentaires qui se retrouvent dans le modèle en granulométrie uniforme n'apparaissent que dans certains cas, laissant place à une mobilité des sédiments discontinue, généralement de proche en proche. La modélisation du transport solide dans ces systèmes à faciès complexes se heurte à la forte variabilité des conditions hyro-sédimentaires. L'abondance de confluences et des fronts de bancs modifie la relation de transport avec les conditions locales. L'influence de la morphologie est prépondérante dans la dynamique du transport solide. / Complex mechanisms involved in braided rivers morphology and the interaction with the grain sorting are slightly studied. Throughout this thesis, we study the morphological signature of a system at equilibrium, and the interaction between the bed morphology and grain sorting. From our small-scale experiments, we studied the prediction of sediment transport. We studied three different small-scale streams, a alternate bars model with heterogeneous sediment (duration 100h), a braided stream model using uniform sand (duration 385h) and a braided stream model using sand and coarse sand mixture (duration 435h). Upstream conditions have been changed several times for each braided stream. It appears that the only one relevant index to compare sediments stages of different streams is the surface above the average slope. To study a single site's evolution, the traditional parameters such as slope or Bed Relief Index (BRI) are relevant enough. We observed different effects of grain sorting. First, grain sorting is responsible of selective depositions and led to active channel migration. The selective deposition leads to bar emergence. Sedimentary lobes that we observed on uniform sand model were rarely noticed on the sand and coarse sand mixture experiment. This results suggests that sediments motion is tiny linked to grain size range. Modeling of sediment transport in such varied morphology faces different problems. Plenty of confluences and fronts bars changes sediment transport and local conditions connections. The influence of morphology is predominant in the dynamic of sediment transport.

Esta Tese traz reflexões sobre processos de produção audiovisual, defendendo a ideia de que essa produção organizada por professores em formação, em relação dialógica com o contexto no qual estão inseridos, interligando as imagens a diferentes aspectos, poderia levar os sujeitos envolvidos nos processos de ensino e aprendizagem ao reconhecimento do valor coletivo dessas práticas. O enfoque principal são os processos de produção audiovisual de professores em formação em Arte, delimitado neste estudo pelo contexto das tramas ecológicas, como um contexto propício a levar à instauração de diálogos, ampliação de campos de referência e produção de sentidos. A interação com as mídias digitais, disponibilizadas no campo educacional, surgem como ferramentas na construção do conhecimento que possibilitam reflexões sobre os processos éticos, estéticos e novos possíveis. O pensamento complexo, possibilitado por um olhar que dialoga com o contexto em que se está inserido e pela interligação de saberes como proposto por Morin, permitiu identificar processos de produção audiovisual, possibilitados por modos de organização e estratégias, através de interações com o meio e com atores sociais, caracterizados por retroações e recursividade que levam à interligação de diferentes conhecimentos. Para análise desses processos foi considerado o dialogismo de Bakthin que gerou os conceitos de polifonia, exotopia e cronotopia, que evidenciam aspectos das várias vozes, tempo e espaço da relação dialógica e atribuição de sentidos à obra criada/observada. A metodologia dessa análise de processos de produção audiovisual dos sujeitos é qualitativa e desenvolveu-se em uma abordagem de pesquisaparticipante, sugerida por Brandão e Borges (2007), que levam em consideração o conhecer, o pensar e o intervir, a exploração da comunidade, a identificação das necessidades básicas e a elaboração de estratégia educativa. Foi considerado ainda a Pedagogia da Autonomia de Freire (2002), no que se refere à escuta das narrativas dos participantes sobre suas experiências cotidianas, entendidas neste estudo, como fator preponderante à pesquisa. Dessa forma, os processos analisados dizem respeito ao resultado de diferentes atividades audiovisuais vivenciadas por professores em formação em Arte e artesãos, produtores de tramas ecológicas ou objetos em fibras vegetais, com diferentes faixas etárias, e restringem-se especificamente aos registros fotográficos e videográficos sobre o processo artesanal desses objetos, interrelacionados ou não aos aspectos culturais e educacionais que envolvem esse fazer. Esses resultados apontam para a importância do desenvolvimento de um olhar dialógico, possibilitado pela interação com as mídias de seu tempo na construção do conhecimento. / This dissertation reflects on audiovisual production processes, defending the idea that this production organized by teachersing training, on a dialogic relation to with context in which they are inserted, linking images to different aspects, could lead the individuals involved in teaching and learning processes to recognize the collective value of these practices. The main focus are the audiovisual production processes of teachers training in art, defined in this study by the context of ecological braided straw, as an enabling environment for the establishment of dialogue, expansion of reference fields and production of meanings as a context conducive to lead to the establishment of dialogue, expansion of reference fields and production of meanings. The interaction with digital media, available in the educational field, appear as tools in the construction of knowledge ethical, aesthetic and possible new processes. Complex thinking, made possible by a look that speaks to the context in which it is inserted and the interconnection of knowledge, as proposed by Morin, identified audiovisual production processes, possible by organizational methods and strategies, through interactions with the environment and with social actors characterized by retroactions and recursion that lead to the interconnection of different knowledge. The analysis of these processes were based on Bakhtin's dialogism and the concepts of polyphony, exotopy and chronotope with the evidence of various voices, time and space of dialogical relationship and attribution of meaning on the work done/observed. The methodology of this analysis of audiovisual production processes of the subject is qualitative and has developed into a research-participant approach, suggested by Brandão and Borges (2007), which take into account the knowledge, thought and action, the exploitation of community, identification of basic needs and the development of educational strategy. It was still considered the Pedagogy of Autonomy Freire (2002), with regard to listening to the narratives of the participants about their everyday experiences, understood in this study as a major factor research. Thus, the processes analyzed concern the result of different audiovisual activities experienced by teachers in training in Art and artisans, producers of ecological braided straw or objects in vegetable fibers, different age groups, and they are limited specifically to photographic records and videographic on the handmade process of these objects, inter-related or not to the cultural and educational aspects involved in this action. These results point to the importance of developing a dialogical look, made possible by the interaction with the media of their time in the construction of knowledge.

The Guará Formation (Upper Jurassic) crops out in the western portion of Rio Grande do Sul along a track with north-south orientation, of which the northern part essentially consists of fluvial deposits with paleocurrent to southwest. Despite the existence of outcrops with good vertical exposure and high lateral continuity, had not yet been carried out detailed studies of fluvial architecture of this unit. Through facies analysis, with vertical logs and lateral sections data, 9 lithofacies composing 8 architectural elements were described and interpreted. These elements are grouped in sandstone bodies of two fluvial styles: (1) Deep perennial braided rivers – composed by simple and composed downstream-accretion elements, small and large-sized hollows, trough cross-stratified sets and overbank sand and fine facies – and (2) Poorly channelized ephemeral braided rivers - characterized by horizontally stratified sandstones and trough cross-stratified sets. Two or more sandstone bodies of same style amalgamate into 10 to 15 m packages representing time intervals with the domain of a river style. These packages alternate vertically separated by hundreds of meters lateral extent surfaces, reflecting intervals with larger and more continuous water discharge (sandstone bodies of deep perennial rivers) or with high energy episodic discharge (with sandstone bodies of poorly channelized ephemeral rivers). The river systems of the proximal portion of the Guará Formation reflects low frequency discharge variations, controlled by the climate. / A Formação Guará (Jurássico Superior) aflora na porção oeste do Rio Grande do Sul ao longo de uma faixa com orientação norte-sul, sendo a sua porção setentrional constituída essencialmente por depósitos fluviais com paleocorrente para sudoeste. Apesar da existência de afloramentos com boa exposição vertical e uma alta continuidade lateral, não haviam sido realizados até o presente momento estudos detalhados da arquitetura fluvial desta unidade. Por meio da análise de fácies, com a elaboração de perfis verticais e seções laterais, foram descritos e interpretados 9 litofácies que compõem 8 elementos arquiteturais. Estes elementos se agrupam em corpos arenosos de dois estilos fluviais: (1) Rios entrelaçados perenes profundos – compostos por elementos de acresção frontal simples e compostas, hollows de pequeno e grande porte, sets isolados com estratificações cruzadas e fácies arenosas e finas externas aos canais – e (2) Rios entrelaçados efêmeros fracamente canalizados – caracterizados por arenitos horizontalmente estratificados e sets isolados com estratificações cruzadas. Dois ou mais corpos arenosos de mesmo estilo se amalgamam em pacotes de 10 a 15 m que representam intervalos de tempo com o domínio de um estilo fluvial. Estes pacotes se alternam verticalmente separados por superfícies de centenas de metros de extensão lateral, refletindo intervalos com descarga aquosa maior e mais contínua (com corpos arenosos de rios perenes e profundos) ou com descarga episódica e de alta energia (com corpos arenosos de rios efêmeros fracamente canalizados). Os sistemas fluviais da porção proximal da Formação Guará refletem variações de descarga de baixa frequência, de controle climático.

The Guará Formation (Upper Jurassic) crops out in the western portion of Rio Grande do Sul along a track with north-south orientation, of which the northern part essentially consists of fluvial deposits with paleocurrent to southwest. Despite the existence of outcrops with good vertical exposure and high lateral continuity, had not yet been carried out detailed studies of fluvial architecture of this unit. Through facies analysis, with vertical logs and lateral sections data, 9 lithofacies composing 8 architectural elements were described and interpreted. These elements are grouped in sandstone bodies of two fluvial styles: (1) Deep perennial braided rivers – composed by simple and composed downstream-accretion elements, small and large-sized hollows, trough cross-stratified sets and overbank sand and fine facies – and (2) Poorly channelized ephemeral braided rivers - characterized by horizontally stratified sandstones and trough cross-stratified sets. Two or more sandstone bodies of same style amalgamate into 10 to 15 m packages representing time intervals with the domain of a river style. These packages alternate vertically separated by hundreds of meters lateral extent surfaces, reflecting intervals with larger and more continuous water discharge (sandstone bodies of deep perennial rivers) or with high energy episodic discharge (with sandstone bodies of poorly channelized ephemeral rivers). The river systems of the proximal portion of the Guará Formation reflects low frequency discharge variations, controlled by the climate. / A Formação Guará (Jurássico Superior) aflora na porção oeste do Rio Grande do Sul ao longo de uma faixa com orientação norte-sul, sendo a sua porção setentrional constituída essencialmente por depósitos fluviais com paleocorrente para sudoeste. Apesar da existência de afloramentos com boa exposição vertical e uma alta continuidade lateral, não haviam sido realizados até o presente momento estudos detalhados da arquitetura fluvial desta unidade. Por meio da análise de fácies, com a elaboração de perfis verticais e seções laterais, foram descritos e interpretados 9 litofácies que compõem 8 elementos arquiteturais. Estes elementos se agrupam em corpos arenosos de dois estilos fluviais: (1) Rios entrelaçados perenes profundos – compostos por elementos de acresção frontal simples e compostas, hollows de pequeno e grande porte, sets isolados com estratificações cruzadas e fácies arenosas e finas externas aos canais – e (2) Rios entrelaçados efêmeros fracamente canalizados – caracterizados por arenitos horizontalmente estratificados e sets isolados com estratificações cruzadas. Dois ou mais corpos arenosos de mesmo estilo se amalgamam em pacotes de 10 a 15 m que representam intervalos de tempo com o domínio de um estilo fluvial. Estes pacotes se alternam verticalmente separados por superfícies de centenas de metros de extensão lateral, refletindo intervalos com descarga aquosa maior e mais contínua (com corpos arenosos de rios perenes e profundos) ou com descarga episódica e de alta energia (com corpos arenosos de rios efêmeros fracamente canalizados). Os sistemas fluviais da porção proximal da Formação Guará refletem variações de descarga de baixa frequência, de controle climático.

Cette thèse porte sur l'étude du comportement mécanique et l'endommagement d'un composite tressé 3D, utilisé pour fabriquer des réservoirs multiformes destinés à l'industrie automobile. L'analyse du matériau se base sur une approche expérimentale et une approche numérique. Sur le plan expérimental, des essais de caractérisation ont permis d'identifier l'ensemble des modules d'élasticité nécessaires pour établir la matrice de rigidité du matériau. De même, des essais expérimentaux ont permis d'étudier le processus d'endommagement du matériau en utilisant deux méthodes de suivie. La première consiste à utiliser une caméra munie d'un zoom pour observer les mécanismes d'endommagement qui se créent au cours du chargement. La deuxième méthode, quant à elle, utilise la technique de l'émission acoustique pour détecter en temps réel les mêmes phénomènes. Le couplage des deux méthodes a permis de dresser la chronologie de l'apparition de ces mécanismes d'endommagement. Sur le plan numérique, une analyse multiéchelle a permis d'évaluer l'influence des fissurations transversales et des décohésions d'interface sur les propriétés mécaniques du matériau. Pour cela, une cellule de base caractéristique de la microstructure a été modélisée. Par une technique d'homogénéisation appliquée à différentes échelles du matériau, les propriétés macroscopiques du composite ont été déterminées à partir de celles de ses constituants de base. Par la suite, des défauts sont introduits de manière discrète sur la même cellule de base. Par le même processus d'homogénéisation à l'échelle mésoscopique, les propriétés du matériau endommagé sont déterminées et comparées à celles du matériau non endommagé. Enfin, un pré-dimensionnement des réservoirs a été effectué en utilisant des critères de rupture classiques pour validation. / This thesis focuses of the mechanical behavior and damage of a 3D braided composite. The material analysis is based on experimental and numerical approaches. First, mechanical tests have identified all the necessary elastic moduli to determine the stiffness matrix of the material. Similarly, experimental tests were performed to study the material damage process using two investigation methods. The first consists on using a camera with a large magnifier in order to observe damage mechanisms created during loading. The second uses the acoustic emission technique to detect in real time the same phenomena. The coupling of the two methods allowed to establish the chronology of the development of these damage mechanisms. In numerical terms, a multiscale analysis approach enables to evaluate the impact of transverse cracks and debonding on the mechanical properties. Thus, a representative cell of the material microstructure is built to predict the macroscopic properties of the material from the properties of its constituents. Defects are introduced during the meshing using a program that allows duplication of nodes at the interfaceto create debonding or to create transverse cracks inside yarns. Through the same homogenization process, the damaged material properties are determined and compared to that of the undamaged material. Finally, a design of tanks are proposed by using strength criteria for their validation.

Erosional issues in the Brahmaputra River in the eastern Himalayas pose increasing pressure on the nearby societies and ecosystems. With a proceeding climate change and increasing anthropogenic disturbance, predictive models are needed to evaluate the effect on sediment transport. Especially in braided rivers, like the Brahmaputra, sediment transport processes imply high demands on numerical models. The objective is therefore to assess the sensitivity of sediment transport on changed river characteristics in the Brahmaputra River, in order to qualitatively evaluate future possible dynamics. Through the one-dimensional steady state model, HEC-RAS 4.1, the braided river was simplified into a single straight channel to enable an extensive reach (700 km) to be modelled. Since little comparative data were at hand, a literature review gathered independent estimates of each parameter. Their natural variability was applied in the sensitivity analysis, and the model produced a suspended sediment load representing approximately 35% of observed data. The sensitivity analysis showed that the channel bathymetry form had a large impact on the model results, whereas the amount of lateral inflow (both surface and subsurface waters) to the main channel flow had a very small impact. Overall, the suspended sediment load were interpreted to be increasing from a future climate change, while further river regulation could counteract such elevation. Further studies are required concerning the river bathymetry in large scale modelling and to address transport of finer cohesive sediments. This methodology proposes a novel approach on how to analyze sediment transport at a large scale that could be used as a tool to interpret future possible changes and ultimately contribute to a better understanding of sediment transport modelling in the area.

Braided channels arise due to high sediment availability in conjunction with regular competent flows and readily erodible banks. Together, these boundary conditions lead to the deposition and reworking of a network of transient bars that characterize the braided planform. However, quantifying the geomorphic response of braided systems to alterations in these boundary conditions is not straightforward, as channels adjust over a wide range of timescales, rendering traditional field-based observation intractable. As such, the development of simple yet robust relationships between channel morphology and sediment transport has the potential to allow predictions of channel response to altered hydrologic or sediment regimes. In this research, I first use laboratory flume experiments to relate particle travel distance during floods (termed particle path length) and the spacing of channel bars in braided rivers (Chapter 2), finding that deposition sites for sediment in transport can be readily predicted by the characteristic confluence-diffluence spacing in a reach. I then use the relationship between path length and channel morphology to build a simple, open-source morphodynamic model for braided rivers that computes sediment transport using path-length distributions derived from bar spacing (Chapter 3). I explore the validity of this model, specifically noting that its modular framework allows exploration of process representations in morphodynamic modeling in ways existing models do not. Finally, I employ the model to determine the role of sediment supply in braided channel bar morphodynamics (Chapter 4). Specifically, I address the relative roles of sediment sourced from upstream versus sediment sourced from within a braided reach in terms of channel morphodynamics at decadal timescales. This research demonstrates that simple scaling relationships, while necessarily imperfect, nevertheless provide insight into morphodynamic processes in braided rivers, while also allowing predictions of channel response to sediment or hydrologic forcing at the timescales of channel adjustment.