OLIVEIRA, Lucivânio Jatobá de, também é conhecido em citações bibliográficas por: JATOBÁ, Lucivânio / Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-08-31T21:36:15Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Maria da Conceição Lima da Silva Albuquerque.pdf: 7953558 bytes, checksum: d9506b683e5e33c0870690589a7bb2d6 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-09-27T17:57:47Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Maria da Conceição Lima da Silva Albuquerque.pdf: 7953558 bytes, checksum: d9506b683e5e33c0870690589a7bb2d6 (MD5) / Made available in DSpace on 2018-09-27T17:57:47Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Maria da Conceição Lima da Silva Albuquerque.pdf: 7953558 bytes, checksum: d9506b683e5e33c0870690589a7bb2d6 (MD5) Previous issue date: 1997-05-15 / A presente pesquisa tem como objetivo geral analisar a integração das características eco-geográficas de parte do município de Ipojuca-PE na qual foram enfatizados os diferentes tipos de meios geodinâmicos e sua utilização. A área localiza-se na REGIÃO Metropolitana do Recife, no Estado de Pernambuco. Apresenta como característica principal a atividade canavieira ocupando quase toda sua área agricultável. Conta ainda com o Porto de Suape, localizado no estuário do Rio Ipojuca, suja construção exerceu forte modificação espacial acarretando alguns problemas de ordem ambiental. Possui na faixa litorânea uma intensa atividade imobiliária fruto da expansão dos horizontes de lazer da Região Metropolitana e das ações governamentais através do desenvolvimento de projetos turísticos de ocupação, ambos exercendo forte pressão ambiental. Em função dos aspectos citados acima, a área vem apresentando modificações significativas de ordem físico-ambiental e sócio-econômica. Tais modificações dizem respeito a desmatamentos, erosão em diversos estágios, desmontes, aterros de manguezais, destruição de terrações flúvio-marinhos, assoreamentos dos cursos d’água, modificação na dinâmica marinha entre outros aspectos da relação ambientes naturais e atividade humana, analisa-se o processo de organização espacial. Os resultados são representados em uma carta na escala de 1:25.000. / La présente recherche a comme objectif général analyser l‘intégration des caractéristiques eco-géographiques d’une partie de la ville d’Ipojuca – PE, dans laquelle les différents types de moyens géodynamiques et leur utilisation ont été enphatisés. L’aire est située dans la Région Métropolitaine du Recife dans l’Etat de Pernambuco. Elle présente comme caractéristique principale l’activé agricole de la canne à sucre qui occupe presque toute l’aire utilisé parr l’agriculture. Il y a encore le Port de Suape, situé dans l’estuaire de la fleuve Ipojuca, dont la construction a exercé une forte modification espacial occasionant des problèmes d’ordre ambiental. L’aire a aussi dans la bande litorainne une intensive activité imobiliaire, résultant de l’expansion des horizonts de loisir de la Région Métropolitaine et des actions gouvernamentalles par moyent du développement de projets turistiques d’occupations, les deux exercent une forte pression ambiental. Em fonction des ces aspects cités ci-dessous, l’aire est em train de présenter des modifications significatives d’ordre physiquo-ambiantal, socio-économique. Telles modifications s’agissent de déboisements, érosion en plusieurs étages, démontes, terrassements de terrains de marecages, destruction de terrasses fluvio-marines, ensablements des cours d’eau, modification dans la dynamique marine entre autres aspects. A travers de l’utilisation d’une méthodologie qui rassemble les aspects de la relation ambiants naturels et activité humaine, on analyse le processus de l’organisation espatialle. Les résultats sont représentés dans une carte dans l’échelle de 1:25.000.

Orientador: Regina Célia de Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-26T17:37:19Z (GMT). No. of bitstreams: 1 Souza_TissianadeAlmeidade_D.pdf: 32201836 bytes, checksum: 1f9faae542290f5310368e4c46d47b21 (MD5) Previous issue date: 2014 / Resumo: As áreas litorâneas são consideradas sistemas de elevada suscetibilidade ambiental, em razão de sua localização na interface oceano-continente. A Ilha Comprida, localizada no litoral sul do estado de São Paulo, foi o último grande evento responsável pela atual configuração da costa paulista, como afirma Ab¿Saber (2003). Apesar de constituir-se em uma Área de Proteção Ambiental e abrigar sistemas ambientais e formas de relevo bastante preservados, a Ilha passa por um processo de parcelamento através de lotes e por degradação ambiental de sua paisagem, o que desperta a necessidade de um estudo de reconhecimento das formas do relevo e de processos geradores de tais formas. Assim, com base na Abordagem Sistêmica aplicada à Geomorfologia, o objetivo desta pesquisa consiste em analisar as alterações ocorridas na dinâmica geomorfológica da Ilha Comprida, através da compreensão da alteração das formas de relevo e de seus processos geradores através de uma análise histórica, com a finalidade de identificar as transformações ocorridas na paisagem da ilha e de contribuir com o planejamento aplicado a áreas litorâneas. Para tanto, foi necessária a realização da cartografia geomorfológica de detalhe da área de estudo em diferentes cenários temporais (1962, 1972, 1981, 2000, 2011-2012). Visando identificar e compreender as alterações ocorridas na paisagem da Ilha Comprida, também foram realizados mapeamentos de uso da terra nos mesmos cenários utilizados para as cartas geomorfológicas. Como resultados da pesquisa, para as cartas geomorfológicas, identificou-se os seguintes compartimentos: Acumulação marinha atual, Acumulação de terraços marinhos, Acumulação de planície fluvial, Acumulação de planície fluviomarinha e Morrete; e as formas de relevo: cordões litorâneos, rebordo de terraço marinho, vales de fundo plano, meandros abandonados, dunas fixas e dunas desmanteladas. A partir da elaboração das cartas de uso da terra, observa-se que as maiores intervenções nas feições do relevo da Ilha Comprida se dão pela especulação imobiliária, com a abertura de loteamentos, arruamentos e expansão urbana. Pode-se afirmar que nos cenários mais antigos (1962 e 1972) a análise da evolução geomorfológica baseia-se em sistemas processos-respostas, pois constatam-se as menores intervenções antrópicas sobre a paisagem da Ilha Comprida, com formas e compartimentos de relevo e características de cobertura vegetal bem preservados. A partir do cenário de 1981 até o mais recente (2011-2012), pode-se considerar a área de estudo como um sistema controlado, pois as atividades antrópicas provocam intensas modificações das formas e de compartimentos do relevo e nas classes de uso da terra, sobretudo no trecho central e Nordeste da ilha, onde se concentra a maioria da população / Abstract: Coastal areas are considered high environmental susceptibility systems, due to the location on the ocean-continent interface. The Comprida Island, located on the southern coast of São Paulo State, was the last major event responsible for the current configuration of the São Paulo coast, as stated Ab'Saber (2003). Although this is an Environmental Protection Area and shelters environmental systems and landforms well preserved, the island undergoes a process of parceling through lots and environmental degradation of its landscape, which arouses the need for a recognition study of landforms and processes generating these forms. Thus, based on the Systems Approach applied to Geomorphology, the main objective of this research was to analyze the changes in the geomorphological dynamics of Comprida Island, by understanding the changing landforms and their generating processes over geological time, with order to identify the transformations occurred in the landscape of the island and to contribute with the planning applied to coastal areas. Therefore, it was necessary to perform the Detailed Geomorphological Mapping of the study area in different temporal scenarios (1962, 1972, 1981, 2000, 2011-2012). To identify and understand the changes in the landscape of Comprida Island, also were performed Land Use Mapping in the same scenarios used for Geomorphological Maps. As a result of the research, for geomorphological maps, the following compartments were identified: Current marine accumulation, Marine terraces accumulation, Fluvial plain accumulation, Fluviomarine plain accumulation and Morrete; and the landforms: beach ridges, marine terrace edge, flat bottom valley, abandoned meanders, fixed dunes and dismantled dunes. Based on the preparation of land use maps, it was observed that major interventions in the relief features of Comprida Island are given by real state speculation, with the opening of allotments, streets and urban expansion. It can be argued that the older scenarios (1962 and 1972) the geomorphological evolution analysis is based on processes-response systems, because were noted the smaller anthropogenic interventions on the Comprida Island landscape, with compartments and landforms and vegetation characteristics well preserved. From 1981 to the latest scenario (2011-2012), one may considerer the study area as a control system, because the anthropogenic activities cause enourmous changes of the compartments and landforms and the type of land use, especially in the central and Northeastern portions of the island, which concentrates most of population / Doutorado / Análise Ambiental e Dinâmica Territorial / Doutora em Geografia

A análise digital de terreno, também chamada de modelagem digital de terreno ou geomorfometria, é uma disciplina que faz uso de ferramentas das ciências da Terra, matemática, engenharia e ciência da computação para a quantificação de variáveis e parâmetros relacionadosà superfície topográfica. Atualmente, o único produto disponível para o estudo de formas de relevo em escala de semi-detalhe a regional, com cobertura quase global e produzido segundo uma única metodologia, portanto livre dos problemas encontrados em produtos cartográficos (qualidade dos mapa, disponibilidade, escala adequada ao estudo etc), é o modelo de elevação Shuttle Radar Topography Mission (SRTM). Este trabalho visou o estudo do relevo da região centro-leste brasileira por meio da caracterização morfométrica de modelos de elevação e da integração entre dados morfométricos, termocronológicos e geofísicos, bem como a avaliação da validade do uso de superfícies aplainadas em correlações estratigráficas regionais. Perfis morfológicos e mapas de orientação de vertentes evidenciam uma estruturação N-S das grandes formas de relevo do centro-leste brasileiro, além da presença de uma organização NW-SE das formas de relevo menores, principalmente na região sudeste, mas observável por toda a área de estudo. A distribuição espacial dos dados termocronolóogicos existentes no Brasil éé bastante heterogênea, com amostragem concentrada nas regiões sul-sudeste e nordeste. Os dados da região sudeste mostram que a ruptura continental não aparece como o evento de resfriamento mais importante, que é marcado pelo grande número de amostras com idades traços de fissão (TF) entre 60 e 80 Ma e que pode ser visto como um evento de soerguimento regional (acompanhado de intensa denudação), dada a variação das elevações das amostras nessa faixa de idade. A tendência de que amostras mais distantes da costa apresentem idades TF mais antigas é sutil. Os dados da região nordeste mostram uma tendência mais clara de aumento da idade com a distância da costa e um conjunto de amostras com idades ao redor de 100 Ma pode ser relacionado ao evento de ruptura continental. De maneira geral, a análise morfométrica não permitiu a identificação de extensas superfícies de aplainamento na área de estudo. As áreas essencialmente planas (com topografia muito suave) estão relacionadas a planícies aluviais (rios São Francisco, Araguaia, Tocantins), a bacias sedimentares cretáceas (Chapadão Ocidental da Bahia, Chapada do Araripe, Bacia Bauru) e a bacias paleozóicas com cobertura cretácea (Bacia dos Parecis), onde configuram superfícies estruturais, concordantes com a disposição sub-horizontal das camadas. Nas regiões de escudo pode-se identificar algumas áreas de relevo suave, porém de extensão restrita. A grande extensão das superfícies estruturais associadas às bacias sedimentares cretáceas parece ter levado vários autores à falsa impressão de continuidade pretérita dessas superfícies, hoje isoladas. Este fato, somado às inferências de \"superfícies cimeiras\" com base no aparente nivelamento de topos de morros em terrenos cristalinos, também levou diversos autores a proporem a extensão de superfícies de aplainamento até a região próxima da costa Atlântica. A integração entre dados morfométricos, termocronológicos e geofísicos não suporta a validade do uso de superfícies aplainadas em correla~ções estratigráficas de âmbito regional. Entretanto, admite-se a aplicabilidade, em escala local, da correlação entre níveis morfológicos distintos. As técnicas morfométricas empregadas neste estudo se mostram válidas não apenas para o estudo da superfíciie topográfica, mas também de superfícies soterradas e de sua paleogeografia. A disponibilidade de modelos de elevação gerados por sensoriamento remoto permite o emprego da análise digital de terreno em escalas local a global, com amplo leque de aplicações , não apenas no estudo das formas de relevo terrestres, mas também de outros corpos planetários. / Digital terrain analysis, or geomorphometry, is the practice of ground-surface quantification, through the application of techniques in Earth sciences, mathematics, engineering and computer science. The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) is currently the only near-global data available to perform local to regional-scale landform analysis. The production of a DEM using a single technique, radar interferometry, means that there is consistency in quality, availability and scale. This work focuses upon the study of landforms in central-eastern Brazil by means of morphometric characterization of DEMs and integration between morphometric, thermochronologic and geophysical data, as well as an evaluation of the validity of use of at surfaces in regional stratigraphic correlations. Morphological profiles and aspect maps show a N-S trend of the major landforms of central-eastern Brazil, while smaller landforms have a NW-SE organization, better observed in the southeast region, but visible throughout the study area. The spatial distribution of thermochronological data in Brazil is highly heterogeneous, with samples clustered in the south-southeast and northeast regions. Data from the southeast region does not show continental break-up as the main cooling event, which is identified by the large number of samples with fission-track ages (FT) between 60 and 80 Ma and that can be seen as a regional uplift event (followed by intense denudation), given the elevation range of the samples in this time span. There is a subtle trend of older FT ages from the coast towards the interior. The trend of older FT ages as distance from the coast increases is better represented in data from the northeast region. Samples with ages around 100 Ma can be related to the continental break-up. Morphometric analyses did not allowed the identification of vast erosional planation surfaces in the study area. Areas with a very smooth topography are related to alluvial plains (São Francisco, Araguaia and Tocantins rivers), Cretaceous sedimentary basins (Chapadão Ocidental da Bahia, Chapada do Araripe, Bauru Basin) and Paleozoic basins with Cretaceous cover (Parecis Basin) where the surface follows the subhorizontal bedding. In shield regions, several low-relief areas can be identified, although they are small in extent. The large extent of low-lying surfaces associated with Cretaceous sedimentary basins has lead several authors to suggest that these { presently isolated { surfaces were continuous. This, added to inferences of \"summit levels\" based on the apparent levelling of hilltops in crystalline terrains, has also lead several authors to suggest that the planation surfaces extend close to the Atlantic shore. The integration of morphometric, thermochronologic and geophysical data does not support the validity of use of at surfaces in regional stratigraphic correlations. However, correlation between distinct morphological levels, at a local scale, is suitable. The morphometric techniques used in this study are valid not only for the analysis of topographic surfaces, but also of buried surfaces and their palaeogeography. The availability of remote sensing generated elevation data allows the application of digital terrain analysis from local to global scales, with a range of applications, not only in the study of terrestrial landforms, but also of other planetary bodies.

Orientador: Fabiano Tomazini da Conceição / Coorientador: Francisco Manoel de Souza Braga / Banca: Roberto Goitein / Banca: Andréia Medinilha Pancher / Banca: Sérgio dos Anjos Ferreira Pinto / Banca: Francisco Sérgio Bernardes Ladeira / Resumo: Nesta pesquisa foram estudadas 4 microbacias hidrográficas que perfazem uma área de aproximadamente 500 km², localizadas na serra da Mantiqueira oriental e Vale do Paraíba, no estado de São Paulo. As microbacias têm suas nascentes mais altas localizadas no setor de cimeira da Mantiqueira, a quase 2000 metros de altitude, onde formam riachos que, posteriormente, descem a escarpa da Mantiqueira de forma abrupta e, em seguida, correm pela planície do Vale do Paraíba, até atingir o rio Paraíba em altitudes muito inferiores que, no geral, estão ao redor dos 550 metros. Nestas microbacias foram coletados dados ambientais relativos aos parâmetros físicos e químicos da água, cobertura vegetal e geomorfologia regional, através do emprego de trabalhos de campo e do uso de geotecnologias . Os dados físicos e químicos foram utilizados para avaliar a dinâmica anual e balanço de massa destes elementos para cada uma das 4 microbacias, uma vez que foram coletados dados fluviométricos e pluviométricos. A análise dos dados físicos e químicos das microbacias demonstrou que as taxas de intemperismo físico e químico são mais acentuadas no alto curso das microbacias e no período mais chuvoso do ano; suas águas pluviais e fluviais apresentaram concentrações dentro dos padrões normais da maioria dos elementos químicos mensurados, com exceção para o pH das precipitações que permaneceu ácido durante todo o ano e as concentrações de Na das águas pluviais que apresentaram valores sensivelmente superiores aos verificados em outros estudos. Nesta pesquisa também foi estudada a ictiofauna, avaliando se existe correlação entre as características geomorfológicas regionais das microbacias estudadas com a riqueza, abundância, diversidade Shannon, equitabilidade e similaridade da fauna de peixes. Os resultados demonstraram que todas as variáveis geomorfológicas regionais utilizadas têm um relevante papel na estruturação das... / Abstract: In this research, were studied 4 micro watersheds that, together, consist of an area of approximately 500 km² distributed in the east sierra of Mantiqueira and Vale do Paraíba in the state of São Paulo. The highest sources of these micro watersheds are located in the summit section of the Mantiqueira at about 2000 meters of altitude where they form streams, which subsequently descend abruptly the Mantiqueira escarpment and then run across the plain of the Vale do Paraíba until they achieve the Paraíba river at much lower altitudes, which, in general, are around 550 meters high. From these micro watersheds were collected environmental data relating to the physical and chemical parameters of water, vegetation and regional geomorphology through fieldwork and the use of geotechnology. The physical and chemical data were used to evaluate the annual dynamic and mass balance of these elements for each of the 4 micro watersheds, once fluviometric and rainfall data were collected. The analysis of the physical and chemical micro watersheds data showed that the rates of physical and chemical weathering are higher in the upper fluvial channels of the micro watersheds and in the rainy season of the year. Their rainwater and river water had concentrations within the normal range for most chemical elements measured except for the pH of precipitation, which remained acid throughout the year, and the Na concentrations in the rainwater showed noticeable higher values than those measured in other studies. In this research, the Ichthyofauna was also studied by evaluating whether there is a correlation between the regional geomorphology characteristics of the studied micro watersheds regarding the richness, abundance, Shannon diversity, equitability and similarity of the fish fauna. The results showed that all regional geomorphological variables used have an important role in the regional structure of fish communities; however, the slope of the main... / Doutor

[pt] A presente dissertação trata da aplicabilidade da cartografia geomorfológica e da geodiversidade ao geoturismo do Parque Nacional da Tijuca, localizado no Município do Rio de Janeiro (RJ). O trabalho possui como objetivo a construção do mapeamento geomorfológico e caracterização da geodiversidade do Parque, fornecendo propostas de aplicação ao geoturismo. A área de estudo está inserida no Maciço da Tijuca no alto curso da bacia de drenagem do rio Tijuca (Setor A- Floresta da Tijuca). Os métodos utilizados foram baseados em técnicas de geoprocessamento e trabalho de campo, divididos em mapeamento geomorfológico, índice de geodiversidade, mapeamento geológico e inventário de sítios de geodiversidade. A geologia é caracterizada pela presença de gnaisses ortoderivados e paraderivados, quartzitos e granitos. O relevo é representado por serras escarpadas, morros altos, colinas e rampas de tálus, colúvio e alúvio. O mapa geomorfológico se baseou na análise do índice de posição topográfica, na qual gerou 10 classes, fornecendo detalhes sobre as vertentes. O índice de geodiversidade, representado por densidade de kernel, forneceu a espacialização da variedade dos elementos abióticos, alternando entre muito baixa e muito alta. O mapa geológico apresentou o detalhamento das litologias encontradas na bacia do rio Tijuca, com destaque a grande presença de quartzitos do Grupo São Fidélis e ortognaisses do Complexo Rio Negro. Foram descritos 28 sítios de geodiversidade, que forneceram muitas informações úteis para a promoção do geoturismo dentro do Parque. A maioria dos pontos de visitação do alto curso da bacia do rio Tijuca possuem caráter geológico e geomorfológico, porém as informações sobre geodiversidade não estão disponíveis. A criação de placas, folder, mapas e diálogos com visitantes e moradores das áreas vizinhas do Parque, irão contribuir na conscientização do público e impulso da divulgação científica. / [en] The present dissertation deals with the applicability of geomorphologic cartography and geodiversity to the geotourism of Tijuca National Park, located in the Municipality of Rio de Janeiro (RJ). The work has as objective the construction of geomorphological mapping and characterization of the geodiversity of the Park, providing proposals for application to geotourism. The study area is inserted in the Tijuca Massif in the upper course of the Tijuca river drainage basin (Sector A- Tijuca Forest). The methods used were based on geoprocessing techniques and field work, divided into geomorphological mapping, geodiversity index, geological mapping and geodiversity site inventory. The geology is characterized by the presence of orthoderivative and paraderivative gneisses, quartzite and granite. The relief is represented by rugged mountains, high hills, hills and thallus ramps, colluvium and alluvium. The geomorphological map was based on the analysis of the topographic position index, which generated 10 classes, providing details about the slopes. The geodiversity index, represented by kernel density, provided the spatialization of the variety of abiotic elements, alternating between very low and very high. The geological map presented the details of the lithologies found in the Tijuca River basin, highlighting the large presence of quartzite of the São Fidélis Group and orthogneiss of the Rio Negro Complex. A total of 28 geodiversity sites were described, providing much useful information for the promotion of geotourism within the Park. Most of the visitation sites in the upper Tijuca River basin have a geological and geomorphological character, but information on geodiversity is not available. The creation of signs, folders, maps and dialogues with visitors and residents of the neighboring areas of the Park will contribute to the public awareness and impulse of the scientific dissemination.

Driftwood is widely recognized as a relevant component of riverine systems due to its complex interactions with flow, sediment transport and vegetation dynamics. In-channel large wood has a relevant geomorphic and ecological role as it enhances morphological diversity and creates a variety of physical habitats that sustain high biodiversity. Its presence can also increase flood risk and therefore wood is often removed from streams especially in densely populated areas. Recent river restoration policies aim to maximise the environmental benefits of driftwood and minimise risks. The study of wood dynamics can provide useful information to define guidelines for sustainable wood management. Multi-thread systems represent a particularly interesting and challenging context for the investigation of wood dynamics because of their complex geometry, the presence of vegetated islands and the frequent, intense changes in channel pattern observed even for moderate discharge fluctuations. However, comparatively few studies focus on driftwood in large braided rivers and limited quantitative information is available on wood transport, deposition and remobilisation in these systems. The goals of the present work are: a) characterising the spatial organisation of wood deposits and identifying typical retention sites and styles; b) analysing the influence of flow regime, channel morphology, wood supply and log properties (size and shape) on dispersal patterns; c) investigating wood remobilisation induced by discharge fluctuations and bed reworking; and d) analysing long-term wood storage volume and budget. A combination of field-scale direct observations, remote sensing techniques and physical modelling was used to investigate wood and channel dynamics. Field-scale monitoring carried out on the Tagliamento River (Italy) allowed the observation of complex interactions and feedbacks between channel, vegetation and wood dynamics. Laboratory simulations – carried out in two large flumes at the University of Trento (Italy) and at the University of Hull (UK) – were employed to investigate individual wood dispersal mechanisms under controlled conditions and to explore the role of governing parameters. In large rivers, floods are the primary driver of wood recruitment through the erosion of vegetated banks and islands; field-scale observations showed that these localised wood inputs control wood storage at sub-reach scale because a large proportion of eroded trees is retained close to the input point in sparse, small jams. Physical modelling highlighted a complex relationships between flow stage and the longitudinal and vertical distribution of wood; high discharge increases the ability of the system to transfer wood, but at the same time generates complex inundation patterns where a larger number of sites are available for wood retention. No clear link between flow stage and the vertical distribution of wood is observed, probably because water surface elevation exhibits small changes with discharge in flat braided river cross-sections. Driftwood element properties also influence deposition patterns; log diameter controls travel distance as it governs flotation and therefore the likeliness of deposition. High element length and complex piece shape sustain the formation of large jams. The presence of a root bole is also associated to short travel distance and low relative elevation. At reach-scale, the spatial distribution of wood is the product of local inputs during major floods and reorganisation of deposits induced by minor events. Wood pattern exhibits a threshold behaviour with supply. High input rates determine very high spatial density and the formation of large, stable jams. Two processes govern wood reorganisation over different time scales, namely network inundation – inducing rapid changes in flow field – and bed reworking. In the first case, the persistence of deposits depends on the magnitude of discharge fluctuations as wood dispersed by small floods is easily removed by larger events. High relative elevation and large jam size enhance wood stability, while the presence of a root wad has a dual effect as it determines large accumulations at low elevation. Channel pattern reworking determines intense turnover of driftwood deposits regardless of supply rate, piece properties and jam size, save for very large accumulations. As a consequence, wood deposition occurs mostly on empty braidplain areas as opposed to pre-existing sites. These results suggests that wood (alone) has little direct effect on reach-scale bed geometry in a large braided river; however, deposited wood significantly influences local hydraulics and morphology, enhancing physical habitat diversity. Moreover, deposited wood favours the accumulation of fine sediment, nutrients and seeds and often exhibits vegetative regeneration. These processes lead to the transformation of instable driftwood pieces into vegetated islands, which in turn can trap more wood. Therefore, wood has a relevant, indirect effect on braided river morphodynamics through the establishment of vegetation, whose presence influences network complexity and evolution.

This thesis develops and tests a classification of ‘near-natural’ European single-thread rivers, which are free to adjust to fluvial processes. The research involves subdividing rivers along a continuum of geomorphological characteristics to assign river reaches to geomorphologically-meaningful classes according to their channel dimensions and forms, and floodplain characteristics. The classification was developed and tested through three research components. First, a preliminary classification was developed using information entirely derived from a new information system containing remotely-sensed imagery and digital terrain data: Google Earth. This research stage required the development of rules for identifying, extracting and standardising information from this source for a large sample of river reaches. 221 single-thread river reaches distributed across 75 European rivers were investigated. Analysis of the derived information resulted in the development of a classification comprising six classes of European single thread river. Second, the robustness of the classification was explored including assessments of (i) the degree to which the classes were interpretable in relation to the geomorphic features they displayed; (ii) the degree to which sub-divisions of the six classes could be identified and justified; (iii) the accuracy of some specific types of information extracted from Google Earth; and (iv) the degree to which the six classes corresponded to expected gradients in two controlling variables: stream power and bed sediment calibre. Thirdly, bar theory was applied to a sample of rivers representative of the six classes. Since bars are an important contributor to river channel form and dynamics, the correspondence of the bars in the six river classes to their expected distribution as indicated by bar theory, provided further confirmation of the robustness of the classification. The outputs of the research are (i) a fully-tested classification of European single-thread rivers; and (ii) a demonstration of how Google Earth can provide valuable information for research in fluvial geomorphology. Some additional future research stages are proposed that could turn the classification into an operational tool in the context of river assessment and management.

Understanding and predicting the effects of width variability and the controls on width adjustment in rivers has a key role in developing management approaches able to account for the physical, ecological and socio-economical dimensions of a river system. Width adaptation in a river occurs due to erosion and accretion of banks, within various geomorphic, environmental and anthropogenic contexts, which set the most relevant factors controlling the morphological dynamics of the river corridor. In turn, changes in channel width imply alterations of the river channel morphodynamics at a variety of space and time scales, implying, for instance, modifications of important controlling parameters, like the width-to-depth ratio, which is closely related to the planform morphology of alluvial rivers. Width adaptation bears crucial implications for river management: on one hand, channel widening may result in loss of valuable land and in the increase of the damage risk of infrastructures in surrounding areas, which are often subjected to increasing pressures related to human settlements and economic activities. On the other hand, several approaches to river restoration are based on the concept of “giving more room to the river”, and thus allow the banks to erode and widen, to increase morphological and physical habitat diversity. In view of these implications, the prediction of width adaptation, understanding of its main causes and controlling factors, and quantification of the riverbed morphodynamic response to width variability is of crucial importance to support effective river management. The practical and engineering interest on stable cross-sections of alluvial channels has attracted a considerable amount of scientific research since late 19th century. Much of the research has focused in developing width prediction tools mostly based on empirical approaches and methods based on extremal hypothesis and to lesser extent on mechanistic methods. In the past two decades, research has advanced in developing numerical models including geotechnical as well as fluvial processes to simulate bank failure mechanism more accurately. Despite significant development on the width predictors, research in controls on width evolution of river channels cannot still be considered a fully settled issue. The study of the morphodynamic response of the riverbed to width variability in space and time is somehow more recent, and has focussed on the dynamics of large-scale bedforms (river bars) that produce a variety of riverbed configurations and planform morphologies. The effect of spatial width variability on river bars has mainly been based on assessing the role of such planform forcing effects to the bed topography, both in case of straight and meandering river channels. The amplitude of width variability has been related to fundamental questions as those behind the transition between single- and multi-thread river morphologies, and most studies consider regular spatial variations of the channel width. Research on the response of channel bed to spatial width variability has mostly consisted of modelling and theoretical approaches, which point out the limit cases of a purely “free” system response, associated with morphodynamic instability, an of purely “forced” bedform pattern by spatial planform non-homogeneity. The large spectrum of mixed configurations between those two theoretical limits has been so far seldom investigated, despite its strong relevance for real river systems. The limits of what can actually be considered a “planform forcing” effect, or has instead a too small variability have never been clarified, a well as its role on the resulting channel morphodynamics. For instance, the effects of small amplitude width variations on straight channels, which may be due to imperfect bank lines or protrusion due to vegetations, on morphodynamics of river bed has been neglected so far. This study has two main scientific goals. The first goal is to quantitatively investigate the role of potentially controlling factors on the width evolution of bedload-dominated straight river channels, including the initial channel width, the flow regime and the sediment supply regime. The major question driving the research is whether a river would attain the same width independently of the initial conditions and whether this would be true for all types of discharge regimes of water and sediment supply. The study is carried out using both laboratory experiments (Chapter 3), analytical model (Chapter 4) and numerical model (Chapter 5) tested with reference to real river data. Integrating the results of the experiments with those of analytical and numerical models allows deriving a more robust and complete understanding of the processes involved, including transient width evolution, time scales to morphodynamic equilibrium, equilibrium conditions and role of each controlling factor. In Chapter 3 a set of controlled laboratory experiments have been performed to study channel adjustments in a movable-bed, erodible-bank channel under different flow and sediment regimes and different initial widths. The long-term width evolution is observed to be independent of initial channel width under uniform formative discharge without upstream sediment supply. Width evolution rate is observed to depend on the initial channel width when the sediment is supplied from upstream with the narrowest initial channel evolving at the highest widening rate and resulting into the widest channel. A physics based analytical model of channel adjustment (Chapter 4) has been applied to some of the experiments described in Chapter 3. Furthermore, in Chapter 5 a field scale numerical model was setup using the flow and topographic data of gravel bed reach of Upper Severn River near Abermule (UK). The trend of width evolution computed by analytical model is also qualitatively in agreement with the observations in the experiments. The results of numerical modeling have further supported the observations in the experiments which reinforce the findings in agreement with laws of physics. The second goal of the present PhD research is to analyze the morphodynamic response of the riverbed to small-scale spatial variability of the channel width, focusing on alternate bars. The main question driving the investigation (Chapter 6) is to which extent small-amplitude, irregular width variations in space affect the morphodynamics of river bars, the fundamental riverbed patterns at the scale of the channel width. The key theoretical question behind this investigation is to which extent “small amplitude” width variations can be considered as a planform forcing, for the channel bed morphodynamic response, and whether it is possible to establish a threshold amplitude below which they may act as a near bank-roughness element. The study is based on hydraulic conditions typical of bedload-dominated piedmont streams, often having flows with Froude numbers around 1 or higher at bar-forming or channel-forming conditions. The study is developed through a numerical modeling approach. Because of the considered hydraulic conditions (close to critical-Froude number) first, a comparison is made between one semi-coupled numerical morphodynamic model, expected to be most suitable for sub critical flows, and one fully-coupled numerical morphodynamic model which can handle Froude-critical flows to assess the potential shortcomings of applying a semi-coupled model under close-to-critial Froude conditions. Such test, (Appendix B) supports the use of both models, and the semi-coupled model is eventually preferred for the advantages in computational speed. Such model is used for the numerical investigations performed in Chapter 6 and to some extent also in Chapter 5. The comparison is based on the reproduction of alternate bars morphodynamics observed in existing sets of flume experiments with fixed banks and super-critical flow conditions. The results of numerical modeling have shown that the small width variations have accelerated the development of the steady bars suppressing the free bar instability. Further investigations reveal that the effects of small width variations to a certain extent can be captured by parameterizing them in the form of increased roughness close to the banks or as small obstructions along the banks.

Increasing energy demand driven by rapid population and economic growth, the need for climate change mitigation, and the depletion of fossil fuels is stimulating the search for renewable, climate neutral energy sources. Hydropower provides an efficient, low maintenance and flexible form of energy, which can provide ancillary benefits such as flood control, water storage and job creation. Yet, the construction of dams for hydropower production has been recognised by scientists as one of the major threats to the ecological integrity of river systems. For instance, the fragmentation of river systems alters the flow, thermal, and sediment regimes of rivers, and restricts the free movement of aquatic organisms. Disruption to the natural flow regime results in the degradation of physical habitat features which generate acoustic stimuli that are relevant to organisms. In addition, initial flooding of terrestrial habitats results in the rapid decay of organic matter, which releases greenhouse gases (GHG) into the atmosphere. Conservation and management of river systems therefore requires a greater understanding of the processes and mechanisms which underpin the ecohydrological impacts of hydropower. In this context, this doctoral thesis aims to investigate: (i), the ramifications of a global boom in hydropower construction, (ii) the prediction of GHG emissions from hydropower reservoirs, and (iii) the temporal and spatial changes in underwater river soundscapes affected by hydropower. Researchers have investigated the social, economic and ecological consequences of reservoir construction for decades. However, the lack of coordinated, georeferenced databases has hindered catchment decision making, and limited the development of regional and global research in particular. In Chapter 1, the primary objectives were to create a high resolution, georeferenced database of hydropower dams under construction or planned to assess the dimension and spatial distribution of hydropower developments, their density relative to available catchment water resources and the future impact on river fragmentation. Data were collected on hydropower schemes under construction or planned with a capacity of 1 MW or above, from government and non-government databases, grey literature and news reports. Spatial analyses were conducted in a geographical information system (GIS) on the extent of global development, impact per water availability and potential consequences for existing status of river fragmentation. The relative contribution of hydropower reservoirs to the global GHG budget, particularly in sub-tropical and tropical regions, remains the subject of intense critical debate. The initial objective of the second study was therefore, to identify principal parameters and underlying processes that drive GHG emissions from reservoirs. The second step was to review global reservoir emission measurements and their source pathways in hydropower systems. Meteorological and landscape derived parameters were then correlated with the GHG measurements in order to assess if and which selected parameters might explain variations in GHG emission data. Similarly, existing empirical models were applied to the measured data to assess their suitability in predictive modelling. Finally, a newly developed process based model (FAQ-DNDC v1.0) was used to simulate ‘net’ CO2 emissions from a newly flooded tropical reservoir and compared to the measured results. The final study (Chapter 3) examined the influence of hydropower systems on the underwater acoustic properties of river habitats. Using recently developed acoustic sensors in addition to traditional hydrophones, the study characterised the temporal and spatial changes in river soundscapes affected by hydropeaking, compared their frequency composition to unaffected river soundscapes, and critically appraised the ecological implications. The results of Chapter 1 indicate that we are now experiencing an unprecedented growth in global hydropower construction. Over 3,700 dams are planned or under construction, primarily in Africa, South America and East Asia. The expansion in dam building will reduce the number of free flowing rivers on a global scale by approximately 21%. The results of Chapter 2 show that variation in measured emissions due to the inherent heterogeneity of the underlying processes, in addition to methodological limitations, impede the prediction of GHG emissions. Source pathways of CO2 are similar for the majority of systems, however, pathways of CH4 emissions are highly variable and dependent on local operating conditions and the configuration of the given hydropower system. A newly developed process based model (FAQ-DNDC v1.0) shows that a mechanistic approach may provide the basis for the ‘net’ assessment of future hydropower reservoirs. Chapter 3 reveals that distinct river soundscapes undergo changes which are highly correlated to hydropower operations, and thus rapid sub-daily changes occur at timescales not often found in natural systems. These changes occur mostly in low frequency bands, which are within the range of highest acoustic sensitivity for fish. In pool habitats affected by hydropeaking, sound pressure levels in the lower frequencies (~0.0315 kHz) may increase by up to 30 decibels. Similarly, sound pressure levels of riffles increase by up to 16 decibels in the low to mid frequencies (~0.250 kHz). Overall, the findings of this thesis have a number of implications for river catchment management. Hydropower construction is taking place in some of the most ecologically sensitive areas of the globe, thus, this research provides a timely contribution to: (i) Provide a foundation for future research at catchment, regional and global scales. For instance, systematic conservation based planning is required to designate ‘no go’ areas to promote the long-term survival of biodiversity. Strategic positioning of future dams or reconfiguration of existing hydropower systems may reduce the combined impacts on biodiversity and GHG emissions without losing power capacity. (ii) Assess driving parameters of GHG emissions, critically appraise current predictive GHG emission models and use a process based approach to simulate ‘net’ emissions from a sub-tropical reservoir. Future reservoirs will sequester, mineralise and emit an increasing quantity of carbon to the atmosphere, and subsequently, will take a greater role in the global GHG budget. This research concludes that, in some cases empirical models may not be suitable for making robust estimations of future GHG’s from hydropower reservoirs. Combining the underlying carbon cycling processes within a process-based model allows the estimation of ‘net’ CO2 emissions from hydropower reservoirs. This approach may be integrated by catchment planners into the future lifecycle assessment of hydropower reservoirs. (iii) Characterise acoustic changes in underwater sound in rivers affected by hydropeaking. The findings emphasise that flow regulation by hydropower results in rapid changes to the amplitude and frequency spectrum of the riverine acoustic environment. These changes persist for longer periods than other forms of anthropogenic sound and may have implications for the whole biota. Thus, future studies should focus on measuring the behavioural and physiological impact on riverine organisms in order to develop guidelines for hydropower licensing.

Looking over a tidal wetland, the tidal network characterised by its intricate system of bifurcating, blind-ended tidal courses clearly stands out from the overall landscape. This tidal landform exerts a fundamental control on the morphology and ecology within the tidal environment. With today’s recognition of the ecological, economical and societal values provided by tidal wetlands, which has been notably reflected in the development of restoration management strategies across Europe and USA, there is a need to fully understand the nature and development of tidal networks as well as their relationships with associated landforms and biotic components (e.g. vegetation), to eventually guarantee the success of current and future restoration practices. Accordingly, this research aims to bring further insights into the bio-physical controls on the geomorphology of tidal networks. To this end, a combination of remote sensing, modelling and field activities was employed. A geo-spatial analysis was performed at Queen Mary, University of London (UK), to address the variability of tidal network patterns. A series of network scale morphometric variables was extracted using airborne LiDAR data among selected tidal networks across the UK depicting different planview morphologies, and supplemented with the collection of corresponding marsh scale environmental variables from published sources. Multivariate statistics were then performed to characterise the variability of tidal network patterns and identify the inherent environmental controls. The analysis has revealed that every network type can be characterised based upon measures of network size and complexity, with each network pattern depicting proper morphometric aspects. Particularly, the stream Strahler order and the median depth of the network main channel have the highest discriminating weight on the patterns investigated. High correlation between the latter variable and network main channel width has revealed that linear, linear-dendritic and dendritic networks followed a transitional gradient in their aspect ratio approximated by a power law and thus are seen to depict similar erosional processes. To the contrary, meandering networks clearly depart from this relationship, and show particular segregation in their aspect ratios with respect to dendritic networks. Globally, differentiation on network morphometric properties has been linked to environmental conditions specific to the marsh physiographic setting within which a tidal network develops. Conceptually, tidal networks seem to adapt to marsh environmental conditions by adopting suitable morphologies to drain their tidal basin effectively.An eco-geomorphic modelling framework was developed at University of Trento (Italy), to address tidal network morphological development. In line with current theories as well as modelling advances and challenges in the field of tidal network ontogeny, emphasis was thus placed on the investigation of tidal channel formation and evolution in progressive marsh accretional context. Under these environmental conditions, tidal network development can be ascribed to the combination of two channel-forming processes: channel initiation results from bottom incisions in regions where topographic depressions occur; channel elaboration results from differential deposition, contributing to the deepening of the tidal channels relative to the adjacent marsh platform. Further evolutionary stages including channel reduction proceed from the horizontal progradation of the marsh platform which may lead eventually to channel infilling. Moreover, both qualitative and quantitative results allude to an acceleration of the morphological development of the synthetic tidal networks with increasing sediment supply. These different observations thus emphasise the prevalence of depositional processes in shaping tidal channels. In a second stage, the investigation was extended to the role of the initial tidal flat morphology as an inherent control on tidal network development, by considering different scenarios of topographic perturbations, which has revealed its legacy on tidal network morphological features. Modelling experiments have also acknowledged salt marsh macrophytes as a potential control on network evolution depending on their biomass distribution within the tidal frame. However, tidal channel morphodynamcis appears to be sensitive to the way biomass growth is mathematically parameterised in the model. In view of the current challenges in transcribing mathematically such a dynamic process and the relevance of bio-physical interactions in driving salt marsh and tidal network evolution, a field survey was conducted in a temperate salt marsh in the Netherlands, as part of the mobility to UNESCO-IHE (Netherlands) in partnership with University of Antwerp (Belgium), to assess vegetation distribution and productivity in the tidal frame. Particularly, emphasis was placed on extending investigations on the possible presence of relationships involving vegetation properties in different climatic and ecological conditions from those characterising these previously documented relationships. Regression analysis has revealed that biomass growth can be expressed as a linear function of marsh relative elevation, providing therefore direct empirical validation for corresponding assumptions reported in the literature and used in the present modelling framework; surprisingly, that increase did not correlate with an increase in species richness and diversity. Analysis of likely associations between vegetation morphometrics and total standing biomass yielded only a single linear relationship linking the latter variable to stem height. In truth, these observations may bear reconsiderations on the global validity of the assumptions used in the formulation of some eco-geomorphic processes which are applied in the study and prediction of wetland resiliency facing climate change.