Este estudo trata da caracterização hidromorfodinâmica de um setor paulista da planície fluvial meândrica do rio Ribeira de Iguape, abordando-se os três níveis da pesquisa geomorfológica de acordo com a concepção de HART (1986), a saber: (a) o nível descritivo da morfologia; (b) o nível descritivo dos materiais superficiais e solos; e (c) o nível analítico interpretativo dos processos, que, no caso, são hidrodinâmicos. Os resultados possibilitaram compreensão da hidromorfodinâmica das planícies fluviais meândricas em ambientes tropicais úmidos e, principalmente, da planície de inundação, podendo servir de subsídios no planejamento físico territorial regional, tendo em vista a importância da ocupação humana dentro desses setores. / The objective of this research is the hydromorphodynamic characterization of the Paulista River Ribeira de Iguape sector, approaching three levels of the geomorphology research according HART (1986), to know: (a) the morphology descriptive level; (b) the superficial materials and ground descriptive level; and (c) the processes interpretation analytical level, or hydrodynamic processes. With these surveys and systematization was possible the partially understanding humid tropical environments hidromorphodynamics trends and, mainly, of the flooding plain, which can be used in the regional territorial physical planning, in view of the importance of the occupation human being on these sectors.

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.

Following the removal of Marmot Dam on the Sandy River, Oregon, several Lidar flights were flown over the area of the former reservoir. The resultant sequential DEMs permitted calculation of reach-scale volumetric erosion and aggradation following dam removal. This allows for change detection across the entire affected reach of the former impoundment rather than just at several cross sections. In the first year there was a net loss of blank sediment in the dewatered reach. Subsequent flights show continued degradation of 145,649 m3 as well as aggradation of 6,232 m3. Sediment transport reached quasi-equilibrium in 2012 with a net change of 65 m3. In addition, this technique allows the extraction of cross-section information which shows that the channel continues to be actively migrating in some areas while also being constrained by bedrock features from past volcanism in some reaches. This study further shows the capability of lidar to measure rates of aggradation and degradation for an entire river system instead of reach specific extrapolations and that repeat lidar flights can more than adequately assess the changing nature of entire stream reaches more rapidly and more cost effectively than traditional field techniques. In addition: The utility of Lidar to do river management with repeat returns, having successive lidar acquisitions run on the watershed level will help us to gain insight into the correlation to precipitation events and geomorphological change in a given reach. Lidar can be used to assess the validity of channel evolution models. Sequential runs of lidar can be used to adjust the overall effectiveness of current CEM's and create new ones that consider reach specific geomorphology. Dam removal projects should incorporate initial lidar flights prior to removal and follow acquisitions based on known CEM's for the region and overall region-specific physiography. Sequential lidar should be used for hazard mitigation and geohazards analysis with an acquisition timeframe that is appropriate for the region's physiography, geology, geomorphology and the return interval of the hazard being monitored.

The Irwin River catchment, located in the central western region of Western Australia, has been the scene of significant geomorphological change over both historical and geological timescales. This thesis focuses on the most recent of these changes, the anthropogenic imprint, through the development of a catchment-scale understanding of system behaviour. Analysis and modelling of changes in the hydrological behaviour of the system indicates that while the Irwin River has displayed a natural susceptibility to large flood events, these have been exacerbated by the widespread clearing of native vegetation throughout the catchment. As a result, when such events do occur, the catchment response is now larger, more direct and has a greater ability to cause erosion. However, the nature and detail of sediment yield processes and stream channel response varies markedly throughout the system. A series of representative channel reaches, as defined by their planform characteristics, geometry and architecture, are presented to illustrate spatial changes in stream channel behaviour. A distinct variation in river morphotypes is seen both downstream throughout the system as well as across the tributary sub-catchments of the Irwin River, Lockier River and Green Brook. This inter and intra sub-catchment variation in stream channel response can be attributed to changes in the boundary conditions and coupling mechanisms in operation throughout the Irwin River system. The pronounced spatial variability in response to human disturbance and the changing nature of catchment-scale connectivity seen in the Irwin River system differs markedly to that reported elsewhere in the literature. Appreciation of the variability in form, behaviour and evolutionary history throughout the Irwin River catchment not only provides the foundation for effective management but also contributes to a wider understanding of fluvial system behaviour. Unlike the majority of existing literature, which tends to identify and measure channel changes in a single catchment where historical variation to the sediment and discharge regime is well known, this study demonstrates the role of boundary conditions in determining the response of the fluvial system to changing environmental controls.

Section 303(d) of the Clean Water Act (CWA) requires states to assess and list all streams that do not meet water quality criteria for their designated use classes. In Tennessee, the Tennessee Department of Environment and Conservation (TDEC) uses macroinvertebrate surveys to assess the condition of streams designated for “fish and aquatic life” and the progress of targeted waterbodies toward meeting established standards for sediment. As of yet, no substrate metric has been established to monitor water quality or to document progress toward water quality improvement with respect to fish and aquatic life in Tennessee. A substrate metric that could be efficiently measured and would represent the needs of aquatic species would be valuable for monitoring streams with known sediment impairment to detect water quality improvement. The objectives of this study were to (1) investigate the relationships between riffle substrates and benthic macroinvertebrate data, provided by TDEC; (2) assess the potential use of substrate metrics as a monitoring tool for benthic habitat status; and (3) examine variation in riffle substrates over time in the Ridge and Valley Ecoregion of Tennessee. Bed and interstitial sediment were characterized at sites corresponding with TDEC macroinvertebrate sampling stations. Bed sediment characteristics were significantly correlated with benthic macroinvertebrate data; however, interstitial fines yielded no significant correlations with benthic macroinvertebrate data. Substrate metrics did not differ significantly between varying levels of impairment; however, they did differ significantly when all impaired sites were combined into a single impairment group. The lack of significant differences between varying classes of reach impairment suggests that substrate metrics may not be able to distinguish impairment at the level necessary for monitoring impairment. However, substrate metrics may be of potential use in monitoring sites where impairment is less ambiguous. To investigate change in riffle substrate over time, three sites were monitored over the course of a year. Preliminary observations showed little change in riffle substrate during the study period, suggesting that seasonal restrictions on substrate surveys are unneccessary.

Meandering rivers and associated vegetation communities are highly dynamic systems that interact through various geomorphic and successional processes. However, much is still unknown about these interactions. Studies that focus on system integration rather than examining fluvial-related and vegetation dynamics individually will benefit science and the management of river systems. Tree communities in riparian areas, although consisting mainly of bottomland hardwood species, can be very diverse. Diversity has been linked to environmental influences such as meander migration, and changes in elevation and soil texture. This study focused on a single meander bend of the lower Trinity River in southeast Texas. The purpose of this research was to examine interactions between soil texture variation and the establishment and succession of riparian tree communities, as such interactions contribute to the formation of complex riparian landscapes. A bend-scale approach was utilized to provide a detailed study of vegetation pattern and of soil texture resulting from sedimentation processes, to examine for any relationships between them. Aerial imagery was used to assist in interpreting patterns of vegetation succession. The field portion of the study collected species and size class data on trees and soil samples for textural analysis. These data were analyzed separately to understand variations in tree communities and soils, but also together, to determine any relationships between soil texture and what tree communities are able to establish. Mean annual flow data from gauges upstream and downstream of the site were analyzed for changes in flow following dam construction upstream, as river regulation could potentially alter the vegetation establishment regime. Results showed five distinct communities or zones of vegetation. Soils on the site were strongly skewed toward finer sands and high silt and clay content. Zone locations and community structure were not directly related to soil texture; however, given species had clear relationships of relative density or dominance with specific soil textures. No changes in flow were noted between pre- and post- dam construction periods, indicating that the riparian system at this site may operate under near-natural conditions. Further studies in species-soil texture interactions, and for rare and invasive species in particular, may prove beneficial in improving understanding of the complex functioning of riparian systems and in providing valuable information for their management and restoration.

Orientador: João Osvaldo Rodrigues Nunes / Banca: José Tadeu Garcia Tommaselli / Banca: Sandra Baptista da Cunha / Resumo: Uma vez que é mais freqüente a cada dia o direcionamento de fortes investimentos para o resgate das potencialidades dos ambientes naturais, devido constantes agressões disseminadas pelo modelo de desenvolvimento adotado nos últimos séculos, este trabalho tem como objetivo o estudo dos aspectos físicos e a dinâmica dos agentes sociais que atuam na área da bacia hidrográfica do ribeirão Palmito, localizada no município de Três Lagoas (MS). Assim, o presente trabalho visa à busca de uma leitura dinâmica da paisagem através das características estruturais e ecológicas da bacia, da leitura espaço-sazonal de alguns componentes do regime hidrológico e hidrossedimentológico, além da caracterização do uso do solo ocupação do relevo. As investigações realizadas e a avaliação da existência ou não de desequilíbrios na paisagem da bacia estudada considerou as características naturais por meio da dinâmica do canal fluvial, assim como os fatores geomorfológicos, geo-pedológicos e hidrológicos da bacia, baseado principalmente no fato de que os materiais podem ser facilmente erodidos em função dos solos frágeis e bastantes espessos da região. Além disso, os fatores que transformam a paisagem através dos tipos de utilização ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A time that is more frequent to each day the aiming of strong investments for the rescue of the potentialities of natural environments, had constant aggressions spread for the model of development adopted in the last centuries, this research has as objective the study of the physical aspects and the dynamics of the social agents that act in the area of the hydrographic basin of the Palmito stream, located in the Três Lagoas city (MS). Thus, the present work aims at to the search of a dynamic reading of the landscape through the structural and ecological characteristics of the basin, of the reading space-seasonably of some components of the hydrologic and hydrossedimentologic regimen, beyond the characterization of the use of the ground and occupation of the relief. The investigations realized and the evaluation of the existence or not of disequilibria in the landscape of the studied basin did not consider the natural characteristics by means of the dynamics of the fluvial canal, as well as the geomorphologics factors, geopedologics and hydrologics of the basin, based mainly on the fact of that the materials can easily be eroded in function of the fragile grounds and sufficiently thick. Moreover, the factors that transform the landscape ... (Complete abstract click electronic access below) / Mestre

xviii, 128 p. : ill. (some col.) / This dissertation investigates the potential impacts of canals and small dams on gravel-bed rivers and methods for documenting those impacts. First, I evaluate the potential for mapping channel depths along the McKenzie River, OR, using 10 cm resolution optical aerial imagery with a hydraulically-assisted bathymetry (HAB-2) model. Results demonstrate that channel depths can be accurately mapped in many areas, with some imagery limitations. The HAB-2 model works well in the majority of the river (R 2 =0.89) when comparing modeled to observed depths, but not in areas of shadow, surface turbulence, or depths >1.5 m. Next, I analyze the relative effects of a small dam and two diversion canals on sediment distribution along bars of the lower McKenzie River. The typical pattern of downstream fining is disrupted at each feature and several tributaries, particularly in the "reduced water reaches" below canal outtakes. Most modeled discharge values necessary to mobilize bar sediments fall at or below the 2-year flood return interval, with the remaining at or below the 5-year flood return interval, generally reflecting the D 50 values at each bar (20-115 mm). The third analysis investigates the potential to document geomorphic impacts of small dams in Oregon at ecoregion extents using air photos and publically available data sets. This analysis highlights data disparity with respect to the collecting agency's mission and the difficulty of using remote sensing for small dams. Though the imagery was not useful in evaluating small dam impacts due to resolution and feature size, the data were useful in mapping the small dam distribution across Oregon and each ecoregion. Sixty-one percent of Oregon land is located in the catchment of at least one small dam and the greatest number of dams per area is in the Willamette Valley ecoregion. Overall, this research suggests that, while the application of these techniques must be improved, our ability to observe, study, and understand rivers is enhanced by remote sensing advancements and the combined use of these methods in river restoration and management. This dissertation includes previously published and co-authored material. / Committee in charge: W. Andrew Marcus, Chairperson; Patricia F. McDowell, Member; Dan G. Gavin, Member; David W. Hulse, Outside Member

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)

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-12-03T07:36:31Z No. of bitstreams: 2 Dissertação - Wallas de Souza Castro - 2015.pdf: 6091228 bytes, checksum: 3a8c31295dc00c579cd64b79adafcefb (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-12-03T07:39:02Z (GMT) No. of bitstreams: 2 Dissertação - Wallas de Souza Castro - 2015.pdf: 6091228 bytes, checksum: 3a8c31295dc00c579cd64b79adafcefb (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-12-03T07:39:02Z (GMT). No. of bitstreams: 2 Dissertação - Wallas de Souza Castro - 2015.pdf: 6091228 bytes, checksum: 3a8c31295dc00c579cd64b79adafcefb (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-24 / Meanders rivers have sinuous channel with singular dynamic of lateral migration by eroding its concave bank and depositing on its convex bank. This dynamic is able to expand and restore fluvial environments when creates a sedimentary environments complex linked to development of floodplain. The nature of preexistent deposits on floodplain, which are remobilized by lateral migration, is important to interpret deposicional dynamics, being central to the identification evolution of meanders. Heterogeneity of the facies is formed by several cycles of sedimentary evolution through channel migration, generating a succession of deposits with different degree cohesion. These depositional environments affect the continuity migration and the evolution of meanders. It was researched the current evolution of meander and riparian vegetation influence and theirs deposit about lateral migration process on downstream Claro river. It was used aerial photographs, satellite images, facies analysis and pin set on the banks to identify the influences of vegetation and material in the migration processes of meanders. The channel showed high mobility verified by the high amount of migration process in 47 years, due to the planforms diffusion and oxbow lakes and by deposits and paleochannel sedimentary facies. The vegetation has not shown attenuating effect against the bank erosion in the two curves analyzed meanders, erosion rates for the segments with vegetation cover were up to 1,3m ahead of the environments of floodplain. It was found that the intensity of channel migration differs between the curves. Migration advances with little resistance from unconsolidated deposits of the current floodplain, whereas in older deposits, pedogenesis and consistent terraces have hindered lateral advance, due to theirs material. / Rios meandrantes possuem canais fluviais sinuosos com dinâmica particular de migração lateral ao erodir suas margens côncavas e depositar nas margens convexas. Esta dinâmica é capaz de ampliar e renovar os ambientes fluviais ao criar um complexo ambiente sedimentar ligado ao desenvolvimento das planícies fluviais. A natureza dos depósitos preexistentes na planície, que são remobilizados pela migração lateral, é importante para a interpretação da dinâmica deposicional, sendo fundamental para identificação da evolução dos meandros. A heterogeneidade das fácies é formada por vários ciclos de evolução sedimentar pela migração do canal fluvial, gerando uma sucessão de depósitos com grau de coesão diferentes. Os próprios ambientes deposicionais afetam a continuidade da migração lateral e a evolução dos meandros. Investigou-se a evolução atual dos meandros e a influência da vegetação ripária ou ciliar e os seus antigos depósitos sobre os processos de migração lateral do baixo curso do rio Claro. Utilizou-se de fotografias aéreas, imagens orbitais, análise faciológica e pinos fixados nas margens para identificar as influências da vegetação e material nos processos de migração dos meandros. O canal fluvial apresentou alta mobilidade, verificada pela a elevada quantidade de processos de migração em 47 anos, em virtude da difusão de feições marginais e lagoas de meandros (oxbow lakes) e pelos depósitos e fácies sedimentares do paleocanal. A vegetação não apresentou efeito atenuador diante da erosão marginal nas duas curvas de meandros analisadas, as taxas de erosão para os segmentos com cobertura vegetal foram de até 1,3m de avanço sobre os ambientes da planície. Atestou que a intensidade da migração do canal apresenta diferenças entre as curvas. A migração avança com pouca resistência entre depósitos inconsolidados da planície fluvial atual, enquanto que nos depósitos mais antigos, pedogeneizados e consistentes dos terraços, tem avanço lateral dificultado, em função dos seus materiais.