Dissertations / Theses on the topic 'Geomorphological'
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Green, Anthony P. E. "Geomorphological modelling of meandering rivers." Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430480.
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Maddock, Ian Philip. "Instream habitat assessment : a geomorphological approach." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/32916.
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Instream habitat assessment methods are required to evaluate the biological quality of streams in relation to flow and channel morphology and to distinguish the effects of river management on the instream biota. A range of techniques are described and developed in this study ranging from a simple reconnaissance survey to the detailed Physical Habitat Simulation Model (PHABSIM) in order to establish a method for the classification of river channels, identification of key parameters that determine the biota and assessment of the influence of flow and bed morphology on habitat availability.
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Wood, Joseph. "The geomorphological characterisation of Digital Elevation Models." Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/34503.
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Techniques and issues are considered surrounding the characterisation of surface form represented by Digital Elevation Models (DEMs). A set of software tools suitable for use in a raster based Geographical Information System (GIS) is developed. Characterisation has three specific objectives, namely to identify spatial pattern, to identify scale dependency in form and to allow visualisation of results. An assessment is made of the characteristics of error in DEMs by identifying suitable quantitative measures and visualisation processes that may be enabled within a GIS. These are evaluated by contour threading a fractal surface and comparing four different spatial interpolations of the contours. The most effective error characterisations are found to be those that identify high frequency spatial pattern. Visualisation of spatial arrangement of DEM error is used to develop a deterministic error model based on local surface slope and aspect. DEMs are parameterised using first and second derivatives of quadratic surfaces fitted over a range of scales. This offers advantages over traditional methods based on a 3 by 3 local window, as geomorphometric form can be characterised at any scale. Morphometric parameters are combined to give a feature classification that may also be applied over a range of scales. Multi-scale measurements are combined to give a feature membership function that describes how properties change with scale. These functions are visualised using modal and entropy measures of variability. An additional method of visualising scale dependency is suggested that graphically represents statistical measures of spatial pattern over a variety of spatial lags. This is found most appropriate for detecting structural anisotropy in a surface. Characterisation tools are evaluated by applying them to uncorrelated surfaces, fractal surfaces and Ordnance Survey DEMs of Lake District, Peak District and Dartmoor.
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Russell, Andrew J. "The geomorphological and sedimentological effects of jokulhlaups." Thesis, University of Aberdeen, 1991. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU045907.
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The aim of this study was to test a predictive model of the geomorphological and sedimentological effects of floods resulting from the sudden drainage of ice-dammed lakes (jokulhlaups). A process-based, conceptual model for channel and sedimentary characteristics was tested within a jokulhlaup routeway near Sondre Stromfjord, west Greenland. River channel change resulting from a jokulhlaup monitored in 1987 was studied in three channel types along the flood routeway: deltaic, high gradient bedrock-controlled, and low gradient confined valley sandur. Flood powers, sediment supply and channel resistance to erosion were found to vary considerably between the channel types. Consequently, amounts of channel change and the character of the sedimentary record showed extreme variation. In addition, parts of the jokulhlaup channel which experienced backwater effects may have experienced two sediment transport peaks. Variations between the character of deposits found within each of the three channel types reflect local differences in sediment supply, stream power and channel resistance to erosion. Deposition in the delta and the sandur records sedimentation related to a number of jokulhlaups, whilst the spillway and the bedrock-confined channel provide a record of the action of the last jokulhlaup as low stage deposits, as well as that of the earliest flood events as high stage deposits. This study has shown that it is possible to predict the morphology of channel macroforms. The internal structure of these macroforms is strongly dependent upon both the amount and character of sediment supplied to the channel during a jokulhlaup. The more detailed the knowledge of the controlling variables for any one channel, the more detailed the resulting predictions are. At present, the model concerns only the products of turbulent, Newtonian, water floods. It may, however, be possible to predict thresholds marking the transition to non-Newtonian flows where sediment supply conditions and hydrograph characteristics are known. The model may also be used in reverse to reconstruct the magnitude and frequency of former jokulhlaups where sufficient geomorphological and sedimentary evidence is available.
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Briggs, Alison Rachel. "The geomorphological performance of restored and rehabilitated rivers." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302352.
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Millington, Catherine. "The geomorphological dynamics of a restored forested floodplain." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443031.
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This thesis investigates geomorphological processes within the forested floodplain of the Highland Water, a small, lowland river in the New Forest, southern England. Geomorphological processes were monitored (a) before restoration, in order to define reference conditions, and (b) after restoration, in order to monitor the performance of the restoration against the reference conditions. The results demonstrate that the restoration was successful at moving the restored system towards target reference conditions by re-connecting the channel and floodplain, and consequently floodplain geomorphological dynamics were increased after restoration. However, the restored floodplain was considerably more connected and more dynamic than an upstream semi-natural reference reach, indicating that the restored channel was perhaps undersized. Floodplain channels were an important geomorphological feature observed on semi-natural floodplains, particularly in association with hydraulically effective wood jams. Experiments into sedimentation and erosion showed that overbank flow scoured the surface and distributed sediment, and rates of erosion and deposition were higher within floodplain channels than elsewhere on the floodplain surface. These channels were therefore a major control over the spatial distribution of energy and materials on the floodplain at the patch, feature and reach scale (10-1 to 102 m). The formation of in-channel wood jams, which force flow overbank, relies on the accumulation of wood. Experiments to investigate transport of small wood recorded travel distances ranging from 0 to over 1000 m. Shorter travel distances were associated with higher in-channel geomorphological diversity, particularly the presence of in-channel wood jams. This thesis therefore provides a greater understanding of the geomorphological processes operating on a forested floodplain in conjunction with monitoring the performance of a river restoration project that incorporated a forested floodplain.
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FÃ, Marcelo Martins de Moura. "Geomorphological Evolution of Natural Site in Fortaleza, CearÃ." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5130.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoO SÃtio Natural de Fortaleza, apesar dos atuais padrÃes de uso e ocupaÃÃo, ainda apresenta uma significativa diversidade de elementos constitutivos, os quais foram abordados neste trabalho sob uma anÃlise geomorfolÃgica que se inicia no longo termo e alcanÃa os dias atuais. Este texto objetiva essencialmente abordar os principais aspectos da gÃnese e evoluÃÃo geomorfolÃgica do sÃtio natural onde atualmente se situa e se desenvolve a cidade de Fortaleza, capital do Estado do CearÃ, Nordeste do Brasil, tendo como elemento norteador e teÃrico o PrincÃpio do Atualismo, associado a um conjunto de tÃcnicas que permitiram o desenvolvimento das anÃlises acerca do tema pesquisado. Ao longo da dissertaÃÃo, dividida em trÃs partes, alÃm de apresentar uma caracterizaÃÃo natural da cidade de Fortaleza e discutir a ciÃncia geomorfolÃgica e o PrincÃpio do Atualismo, tratamos dos principais elementos da evoluÃÃo morfoestrutural da Ãrea ao longo do CretÃceo, bem como dos perÃodos TerciÃrio e QuaternÃrio da Era CenozÃica e seus eventos intrÃnsecos, eventos estes, essenciais para o inÃcio da configuraÃÃo atual do meio fÃsico analisado. Com relaÃÃo aos aspectos mais recentes da evoluÃÃo geomorfolÃgica analisada, discutimos os relevos presentes no sÃtio natural de Fortaleza, com caracterizaÃÃes e anÃlises mais verticalizadas, bem como da participaÃÃo, condicionante e condicionada, desses relevos na dinÃmica atual. Finalizando o trabalho, analisamos o principal processo de degradaÃÃo da paisagem analisada, o processo de urbanizaÃÃo de Fortaleza, com a expansÃo da malha urbana e seus perÃodos mais significativos, citando suas causas, as direÃÃes dessa expansÃo e, principalmente, os elementos da paisagem alterados pela urbanizaÃÃo, bem como, os processos de degradaÃÃo ambiental presentes no cotidiano da cidade no sÃculo XXI. Os resultados obtidos puderam apontar as feiÃÃes geomorfolÃgicas resultantes dos processos morfoestruturais de idade CretÃcea e ainda presentes na paisagem, bem como sua influÃncia para os processos posteriores. AlÃm disso, apresentamos uma hipÃtese evolutiva para a deposiÃÃo da FormaÃÃo Barreiras ao longo do TerciÃrio na Ãrea em tela, bem como uma proposta de um possÃvel paleo-curso do rio CocÃ, principal rio da cidade de Fortaleza, o qual teria sido alterado ao longo do QuaternÃrio atà alcanÃar suas caracterÃsticas atuais. Com base no mapeamento realizado e analisado, propomos uma classificaÃÃo para as lagoas ainda presentes e que constituem o sÃtio natural de Fortaleza. Por fim, apresentamos as principais caracterÃsticas morfolÃgica da cidade, bem como o estÃgio atual dos relevos da cidade e seu mÃtuo inter-relacionamento. Finalizando, analisamos a influÃncia do processo de urbanizaÃÃo na degradaÃÃo dessas feiÃÃes, os fatores e os efeitos da pressÃo exercida pelo meio antrÃpico sobre o sÃtio natural, a preocupaÃÃo com os rumos desse processo, a necessidade de se pensar e repensar este quadro, bem como, a importÃncia de se conhecer esse sÃtio natural, esse meio fÃsico tÃo presente no cotidiano de todos os citadinos e, ao mesmo tempo, ignorado e/ou desconhecido na sua essÃncia e dinÃmica.
The natural site of Fortaleza city, despite of the present standards of use and occupation of the soil, still presents a significant natural diversity, which were approached in this work under a geomorphological analysis that is initiated in the geological long term and achieves in the present days. The objectives ot the work are the main aspects of the geomorphological genesis and evolution of the natural site of the city of Fortaleza, capital of the State of CearÃ, Northeast of Brazil, having as theoretical support the Principle of Actualism, associated to an assembly of techniques that permitted the development of the analyses about the subject researched. The work, divided in three part, besides presenting a natural characterization of the city of Fortaleza, highlights the main elements of the morphostructural evolution of the area during the Cretaceous, the Quaternary and Tertiary periods and its inherent events. Regarding the most recent aspects of the geomorphological evolution, we discuss the present reliefs of the natural site of Fortaleza, with characterizations and vertical analyses, as well as the role of these reliefs in the present dynamics. Finalizing the research, we analyze the main process of environmental degradation of the landscape associated to the more significant urban development of Fortaleza, as well as the consequences of the environmental degradation for the routine one of the city in the century XXI. The results obtained could indicated the geomorphological features resultant of the action of geomorphological process during the Cretaceous still presents in the landscape, as well as its influence in the subsequent geomorphological evolution. Besides, we present a hypothesis of evolution for the deposition of the Barreiras Formation during the Tertiary, as well as a proposal of a possible paleo-valley of Cocà River, the main river of the city, which would have been changed during the Quaternary until achieve its present characteristics. On the basis of the mapping carried out and analyzed, we also propose a classification for the ponds that caractherized the natural site of Fortaleza. Finally, we present the main morphological characteristics of the city, as well as the present situation of its relifs. Finalizing, we analyze the influence of the process of development in the degradation of those features, the factors and the effects of the pressure exercised by the society, the worry about the way this situation is developing, the need of thinking and rethinking these conditions, as well as the importance of the natural site of the city, not well known to their citizens, in its essence and dynamics.
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Tily, Rachael. "Space, research objects, and interdisciplinarity in geomorphological inquiry." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c8a8ffe6-a018-4696-817d-8f98df1d2d4d.
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This thesis considers (inter)disciplinary spaces and research objects associated with geomorphology. Employing an ethnographic methodology, established Actor-Network Theory (ANT) themes are examined; the study considers the displacement of research objects amid the spaces of scientific inquiry and the role played by a range of actors in enabling this displacement. However, these well-known themes are given new impetus; the thesis seeks to address deficiencies in ANT accounts of space and it offers an alternative approach to conceptualising scientific research objects. Building on this analysis it considers how the spaces of geomorphological inquiry are reworked to accommodate interdisciplinary research objects. In this way, the study provides a strong theoretical contribution to the literature. However, this theoretical contribution is complemented by an important empirical base. The study is one of only a few Science and Technology Studies (STS) analyses to consider the geosciences. Focusing on late twentieth and early twenty-first century geomorphology, it provides an insight into an interdisciplinary field of research found in both geography and geology departments. In this way it offers an important contribution to the histories of geography literature and the literature on interdisciplinarity. Relatedly, through its attention to the interdisciplinary field of biogeomorphology, the study provides a bridge between existing STS literatures on the biosciences and nascent explorations of the geosciences.
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Micallef, Aaron. "Failure processes in submarine landslides : a geomorphological approach." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/55502/.
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This thesis presents a novel technique for the quantitative characterisation of bathymetric data sets. The technique integrates three main geomorphometric methods: morphometric attributes and their statistical analyses, feature-based quantitative representation, and automated topographic classification. These methods allow useful morphological information to be extracted from bathymetric data and can significantly enhance submarine geomorphological investigations. The methods are applied to bathymetric data from the Storegga Slide, one of the largest known submarine landslides, to investigate three aspects of submarine mass movements: spreading, fractal statistics and morphology and slide development. The morphological signature of spreading, in the form of a repetitive pattern of ridges and troughs, covers at least 25% of the Storegga Slide scar. Two modes of failure can be identified for submarine spreading. The first involves retrogressive slide development via the unloading of the headwall. The second entails the extension of a thin coherent slab of semi-consolidated material downslope by gravity. Both modes of failure involve the break up of surface sediment units into coherent blocks and their displacement along planar slip surfaces. The block movement pattern entails an exponential increase of displacement, and thinning of the failing sediment, with distance downslope. Loss of support and seismic loading are the main potential triggering mechanisms of submarine spreading. Analysis of headwall morphologies within the Storegga Slide reveals the occurrence of spatial scale invariance. One explanation for this scale invariance is that the Storegga Slide is a geomorphological system that may exhibit self-organised criticality. Spatial scale invariance may also be linked to the retrogressive nature of the Storegga Slide. The shape and fractal dimension of headwalls, on the other hand, can be used as a proxy for the type and number of the formative mass movements. A detailed reconstruction of the development of the north-eastern Storegga Slide shows that after the initial evacuation of the surface sediment as turbidity currents, the area failed as an extensive spread. The spreading blocks subsequently underwent higher displacement and remoulding, and were partly removed by debris flows and turbidity currents. The renewed instability within the spreading areas may have been related to gas hydrate dissociation and pore pressure increases due in response to the changing overburden, and the distribution of contourite drift deposits within underlying palaeoslide scars.
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Belden, Deborah Jeanne. "Geomorphological mapping of the K2 area, Pakistan using GIS and remote sensing." Diss., [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-06112008-121208/.
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Erlingsson, Ulf. "Geomorphological development of the bottoms off Österlen, southernmost Sweden." Uppsala, Sweden : Uppsala University, Dept. of Physical Geography, 1990. http://catalog.hathitrust.org/api/volumes/oclc/22874540.html.
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Brimicombe, A. J. "The application of geomorphological triangular databases in geotechnical engineering." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1985. http://hub.hku.hk/bib/B31207157.
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Entwistle, Neil Steven. "Geomorphological effectiveness and maintenance of a riffle-pool sequence." Thesis, University of Salford, 2011. http://usir.salford.ac.uk/26664/.
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Riffle-pool sequences in gravel-bed rivers provide the template for a number ol fish and invertebrate habitats and their morphological complexities create spatial hydraulic variation over the flow regime that is logistically impossible to measure completely in the field. The mechanisms responsible for riffle-pool maintenance are unclear and despite contributions from many researchers, no conclusive explanation has been developed. There is much debate over the popular velocity reversal hypothesis, where it is generally acknowledged that at low flows the maximum bed shear stress in the channel occurs across the riffle, but at higher less frequent flows areas of maximum bed shear stress can switch to the pool. Sediment interactions control fluvial forms and processes, as such specific analysis of spatial hydraulic patterns in boundary shear stress are required to aid understanding of riffle-pool system behaviour and gain the insight in to the transport capacity that can scour sediment deposited in the predominandy low energy, lower competence pools and thereby provide a mechanism for maintenance ol riffle-pool morphology. Terrestrial LiDAR captures reach scale topographical data to yield a 0.02 m digital elevation model and provides input to three-dimensional computation fluid dynamics software (CFD), where the spatial distribution and area! extent of bed shear stress, surface flow velocities and potential sediment entrainment over the discharge range are investigated for a 188 m gravel-bed reach of Kingsdale Beck, UK. With increasing discharge, spatial distributions of shear stress are revealed, which, until now, have been largely overlooked using previous cross-sectional analysis, highlighting the influence of pool tails as discharge rises. Results show some agreement with past literature on reversal with higher shear stress zones associated with riffles. As discharge increases pools are shown to become more dominant, however the existence of multiple reversals shows that while reversals do occur, they may be short-lived and marginal in magnitude, providing inherent problems with current theory. The overall temporal maintenance of the riffle-pool sequence is more explicitly linked with the long term flow regime, with the flows responsible for moving pool sediment closely confined to near bankfull discharge. Results indicate that potential to entrain sediment from pools occurs only from 85% bankfull. Discharges less than 85% bankfull are suggested to be responsible for maintaining the riffle-pool morphology through flow routing and bed shear stress reversal, however, they are not capable of potentially entraining sediment from the deepest pools. Combined CFD simulations with temporal discharge dominance derived from triangulated rainfall and the Revitalised FSR/FEH rainfallrunoff methodology, highlight the role of rarer more extreme flows in terms of explaining sediment entrainment from pools. At high flow Kingsdale Beck creates a competent sub channel, where a continuous sinuous channel with higher levels of bed shear stress develop with embryonic lateral bars, increasing potential sediment entrainment following the line of thalweg. As flow velocity decreases conventional rifflepool hydromorphology re-establishes and provides a new proposal for the maintenance of a riffle-pool sequence.
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Hansen, Andrew. "Semi-automated geomorphological mapping applied to landslide hazard analysis." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/504.
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Computer-assisted three-dimensional (3D) mapping using stereo and multi-image (“softcopy”) photogrammetry is shown to enhance the visual interpretation of geomorphology in steep terrain with the direct benefit of greater locational accuracy than traditional manual mapping. This would benefit multi-parameter correlations between terrain attributes and landslide distribution in both direct and indirect forms of landslide hazard assessment. Case studies involve synthetic models of a landslide, and field studies of a rock slope and steep undeveloped hillsides with both recently formed and partly degraded, old landslide scars. Diagnostic 3D morphology was generated semi-automatically both using a terrain-following cursor under stereo-viewing and from high resolution digital elevation models created using area-based image correlation, further processed with curvature algorithms. Laboratory-based studies quantify limitations of area-based image correlation for measurement of 3D points on planar surfaces with varying camera orientations. The accuracy of point measurement is shown to be non-linear with limiting conditions created by both narrow and wide camera angles and moderate obliquity of the target plane. Analysis of the results with the planar surface highlighted problems with the controlling parameters of the area-based image correlation process when used for generating DEMs from images obtained with a low-cost digital camera. Although the specific cause of the phase-wrapped image artefacts identified was not found, the procedure would form a suitable method for testing image correlation software, as these artefacts may not be obvious in DEMs of non-planar surfaces.Modelling of synthetic landslides shows that Fast Fourier Transforms are an efficient method for removing noise, as produced by errors in measurement of individual DEM points, enabling diagnostic morphological terrain elements to be extracted. Component landforms within landslides are complex entities and conversion of the automatically-defined morphology into geomorphology was only achieved with manual interpretation; however, this interpretation was facilitated by softcopy-driven stereo viewing of the morphological entities across the hillsides.In the final case study of a large landslide within a man-made slope, landslide displacements were measured using a photogrammetric model consisting of 79 images captured with a helicopter-borne, hand-held, small format digital camera. Displacement vectors and a thematic geomorphological map were superimposed over an animated, 3D photo-textured model to aid non-stereo visualisation and communication of results.
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Hansen, Andrew. "Semi-automated geomorphological mapping applied to landslide hazard analysis." Curtin University of Technology, Dept. of Spatial Sciences, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=17998.
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Computer-assisted three-dimensional (3D) mapping using stereo and multi-image (“softcopy”) photogrammetry is shown to enhance the visual interpretation of geomorphology in steep terrain with the direct benefit of greater locational accuracy than traditional manual mapping. This would benefit multi-parameter correlations between terrain attributes and landslide distribution in both direct and indirect forms of landslide hazard assessment. Case studies involve synthetic models of a landslide, and field studies of a rock slope and steep undeveloped hillsides with both recently formed and partly degraded, old landslide scars. Diagnostic 3D morphology was generated semi-automatically both using a terrain-following cursor under stereo-viewing and from high resolution digital elevation models created using area-based image correlation, further processed with curvature algorithms. Laboratory-based studies quantify limitations of area-based image correlation for measurement of 3D points on planar surfaces with varying camera orientations. The accuracy of point measurement is shown to be non-linear with limiting conditions created by both narrow and wide camera angles and moderate obliquity of the target plane. Analysis of the results with the planar surface highlighted problems with the controlling parameters of the area-based image correlation process when used for generating DEMs from images obtained with a low-cost digital camera. Although the specific cause of the phase-wrapped image artefacts identified was not found, the procedure would form a suitable method for testing image correlation software, as these artefacts may not be obvious in DEMs of non-planar surfaces.Modelling of synthetic landslides shows that Fast Fourier Transforms are an efficient method for removing noise, as produced by errors in measurement of individual DEM points, enabling diagnostic morphological terrain elements to be extracted. Component landforms within landslides are complex entities and conversion of the automatically-defined morphology into geomorphology was only achieved with manual interpretation; however, this interpretation was facilitated by softcopy-driven stereo viewing of the morphological entities across the hillsides.In the final case study of a large landslide within a man-made slope, landslide displacements were measured using a photogrammetric model consisting of 79 images captured with a helicopter-borne, hand-held, small format digital camera. Displacement vectors and a thematic geomorphological map were superimposed over an animated, 3D photo-textured model to aid non-stereo visualisation and communication of results.
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Liddaman, Laura Claire. "Geospatial patterning and the hydro-geomorphological function of eroding peatland." Thesis, University of Manchester, 2009. https://www.research.manchester.ac.uk/portal/en/theses/geospatial-patterning-and-the-hydrogeomorphological-function-of-eroding-peatland(eff67576-3bac-4d8e-91a3-353af709f707).html.
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Richards, Danette Trudy Ward. "Geomorphological and environmental studies of karst, Northwest Nelson, New Zealand." Thesis, University of Canterbury. Geology, 2003. http://hdl.handle.net/10092/5560.
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This study describes the characteristics of the karst terrains and evaluates the surface and subsurface processes operating on the karst systems located between the Takaka and Riwaka Valleys, northwest Nelson, New Zealand. The purpose of this study is to differentiate between natural environmental and human induced changes in the karst system, and where possible, quantify human impacts.
Detailed geomorphological mapping at 1:7500 scale was used to compile an inventory of the karst geomorphology. Geomorphological classification of the surface karst features and an assessment of the lithological and geological variations resulted in the identification of eight karst land systems or zones, in which a similar pattern of topography, hydrology, surface features and soils are recognised. Based on the predominant landforming processes, the karst zones: Kairuru, Takaka Plateau, Canaan South, Canaan North, Pikikiruna, Takaka Walkway, East Takaka and Pohara, are categorised into three groups.
Solution is the dominant process in the first group (Takaka Plateau and Takaka Walkway) which is characterised by internal drainage and a lack of surface streams, rolling topography, numerous, well-formed dolines and karren, and exposed rock surfaces. In the second group (Canaan South, Canaan North, and Pikikiruna), wide karst valleys, numerous alluvial dolines, covered rock surfaces and focused allogenic recharge occur in response to combined fluvial and solutional processes operating on low slope angles. Fluvio-karst processes are also active in the third group, comprising the Kairuru, East Takaka and Pohara zones. This group is characterised by incised karst valleys, mixed drainage systems, steep slopes, and limited doline development. It varies from the low slope - fluviokarst group in that overland flow and lateral solution are common because of the steeper slope gradients.
The eight karst zones are useful management units and the vulnerabilities of the karst to human activities has been evaluated using these zones. The primary impact in the zones of the first group is soil erosion. The presently exposed marble surfaces in these karst zones reflect the loss of 10 - 30cm of soil following land clearance c.100 years ago. The impacts of stream and subsurface sedimentation and water quality degradation dominate in the other zones because of focused runoff, allochthonous soils and higher intensity of land use.
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Cox, Thomas E. R. "Spatial and geomorphological analysis of mammoth localities in western Oklahoma." Thesis, Oklahoma State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1567304.
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Up until recently research on Paleoindian archaeology has focused on Clovis hunters and the demise of 35 genera of megafauna at the end of the Pleistocene. However, with increasing evidence of Pre-Clovis settlement many megafaunal sites older than Clovis are now under scrutiny. In this endeavor, geoarchaeology plays a key role, particularly with assessing the stratigraphic and geomorphological aspects of sites suspected of being Pre-Clovis. This Thesis looks at, and analyzes three mammoth sites in western Oklahoma; Helena, Grandfield, and Foss. These sites were analyzed on a geologic, geomorphologic, hydrologic, anthropologic, and soil pedogenic basis. Understanding of soils and their developmental processes can help give us a better understanding of the landscape and the environment in which they were formed. These sites were then compared to known sites Domebo, Hajny, and Burnham, all of which have had both an absolute date and an in depth soil analysis. The purpose of the comparison is to try and apply relative dating to a site when absolute dating is not obtainable, either due to funding, or technical issues that prevent obtaining a reliable date. It has been hypothesized that older mammoth finds should be found in higher terraces, while those of younger age, possibly with archaeological significance, should be found in lower terraces near flood plains. The three mammoth sites studied through this research are associated with lower terraces regardless of age. This example shows how complex the relationship is between site age and site distribution in the landscape. This research shows also how important is to evaluate soil development for estimating relative ages. This approach in turn is important for assessing late Pleistocene paleontological sites with potential association with Pre-Clovis human populations.
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Adams, Beverley Joanne. "A geomorphological interpretation of saltmarsh channel network morphology and function." Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/1317552/.
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Although tidal channel networks are a near-ubiquitous feature of saltmarsh environments developed on the marine sedimentary shores of Britain, only limited progress has been made towards achieving a scientific understanding of their morphological characteristics and the physical functions that they perform. Based on data acquired from a combination of high resolution aerial photography and field survey, a range of descriptive indices and morphometric measures are used to characterise planimetric, longitudinal and cross-sectional adjustment in saltmarsh channel networks from 29 localities around England and Wales. In accordance with the extensive methodological approach employed during this exploratory phase of the study, regularities and distinguishing features of the selected formations are interpreted in terms of broad-scale environmental controls, which represent the relative intensity of erosional versus resistive forces. While statistical analyses suggest that creek morphology reflects a multiplicity of influences, the strongest bivariate associations, between tidal prism and cross-sectional geometry, are consistent with the finding of earlier process studies that creek morphology is principally adapted to perform a conveyance function. Theoretically-based mathematical models are employed to more fully elucidate relations of causality between creek morphology and function. This intensive investigation utilises Brancaster Marsh, Norfolk as an illustrative case study. The availability of airborne laser altimetry (lidar) for this site facilitates the evaluation of alternative models of channel function. Optimality models of angular geometry are implemented at a network-scale, and cross-sectional adjustments are modelled with reference to the concept of stability shear stress. While of interest from a geomorphological perspective, the insights offered into creek morphology and function are also relevant to the field of coastal engineering. Here, they provide an empirical basis for post-project appraisal, and may lead to theoretical guidelines for the design of tidal channel networks, as an integral component of saltmarsh restoration and flood defence realignment schemes.
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Skinner, Kevin Shaun. "Geomorphological post-project appraisal of river rehabilitation schemes in England." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324063.
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Shen, Hsu-Min. "Geomorphological and tectonic controls on coastal erosion, Huatung, eastern Taiwan." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271172.
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Freire, Francis. "Acoustic characterization of submarine geomorphological features in the Polar Oceans." Licentiate thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-103370.
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Marine glacial environments contain unique seafloor features resulting from the dynamic glacial processes. Studying these submarine geomorphological features can help us understand the glacial paleo-environments so that we can predict the likely responses of present day glaciers and ice sheets to future changes in the climate. This thesis details different approaches in understanding glacial seafloor features using acoustic systems. It focuses on the novel technique of automated mapping seafloor properties using the backscatter intensity collected by acoustic multibeam echosounder systems (MBES). The aim of this thesis is to assess the potential of this unexploited data source in characterizing different glacial landforms in the polar oceans. This is done by examining the voluminous backscatter data collected by Swedish icebreaker Oden from different cruises to the polar oceans and employing an automated backscatter processing technique, the ARA algorithm, to extract surficial sediment characteristics. The results from the sediment characterization are used together with outputs from other marine acoustical systems and sediment core data to understand formational processes of the glacial submarine features. Operational issues encountered in using this technology and its viability as a tool in characterization of glacial seafloor features are discussed and suggestions are given on the improvements needed to effectively implement the method in future studies. The final part of the manuscript is a paper, published in Geo-marine Letters, where I and my co-authors show a practical application of the acoustic systems ability to characterize geomorphological features of a mass-wasting event in the deepest part of the Arctic, the Molloy Hole.
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Udugbezi, Emmanuel. "Evaluating interferometric synthetic aperture radar coherence for coastal geomorphological changes." Thesis, University of Dundee, 2018. https://discovery.dundee.ac.uk/en/studentTheses/b127af25-c290-4fdf-ac44-96c77449fb59.
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Interferometric Synthetic Aperture Radar (InSAR) is an established technique which has been applied to Earth surface displacement analysis and topographic reconstruction. Two complex coherent SAR acquisitions of the same scene are combined to form an interferogram from which surface displacement or terrain measurements are made. The similarities between both SAR signals is captured in the coherence and its magnitude is determined by the spatial separation between acquiring antennas and the changes (if any) to the physical characteristics of the scattering target in the duration between both SAR acquisitions. Both of these products derivable from the interferometric process have been applied in this study with the aim of enhancing monitoring and assessing changes in the coastal environment, with emphasis on the coastal geomorphology. A combination of remote sensing data acquired for Montrose Bay, NE Scotland, has been used to analyze changes to the geomorphology of the beach and dune system in terms of sediment volume analysis, erosion and accretion processes and shoreline changes over a short-term period of 4 years. The interferometric coherence was applied to detect changes to the dune morphology, which have been actively eroding at the southern flank of the Bay. The interferometric analysis presented in this thesis was based on SAR data acquired by the Sentinel-1 SAR antenna and the results demonstrated the limitations of the sensor for terrain mapping and DEM reconstruction. In addition, the significance of the vegetation on the interferometric coherence was demonstrated. However, the results have shown that temporal baseline remained a significant consideration in the application of interferometric coherence in highly dynamic environments such as the coastal environment.
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Iida, Tomoyuki. "A stochastic hydro-geomorphological model for shallow landsliding due rainstorm." 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/157184.
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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものであるKyoto University (京都大学)
0048
新制・論文博士
博士(理学)
乙第10072号
論理博第1351号
新制||理||1115(附属図書館)
UT51-99-G549
(主査)教授 奥西 一夫, 教授 千木良 雅弘, 教授 佐々 恭二
学位規則第4条第2項該当
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Höfler, Veit, Christine Wessollek, and Pierre Karrasch. "Modelling prehistoric terrain Models using LiDAR-data: A geomorphological approach." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35056.
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Terrain surfaces conserve human activities in terms of textures and structures. With reference to archaeological questions, the geological archive is investigated by means of models regarding anthropogenic traces. In doing so, the high-resolution digital terrain model is of inestimable value for the decoding of the archive. The evaluation of these terrain models and the reconstruction of historical surfaces is still a challenging issue. Due to the data collection by means of LiDAR systems (light detection and ranging) and despite their subsequent pre-processing and filtering, recently anthropogenic artefacts are still present in the digital terrain model. Analysis have shown that elements, such as contour lines and channels, can well be extracted from a highresolution digital terrain model.
This way, channels in settlement areas show a clear anthropogenic character. This fact can also be observed for contour lines. Some contour lines representing a possibly natural ground surface and avoid anthropogenic artefacts. Comparable to channels, noticeable patterns of contour lines become visible in areas with anthropogenic artefacts. The presented work ow uses functionalities of ArcGIS and the programming language R.¹ The method starts with the extraction of contour lines from the digital terrain model. Through macroscopic analyses based on geomorphological expert knowledge, contour lines are selected representing the natural geomorphological character of the surface. In a first step, points are determined along each contour line in regular intervals. This points and the corresponding height information which is taken from an original digital terrain model is saved as a point cloud. Using the programme library gstat, a variographic analysis and the use of a Kriging-procedure based on this follow.
The result is a digital terrain model filtered considering geomorphological expert knowledge showing no human degradation in terms of artefacts, preserving the landscape-genetic character and can be called a prehistoric terrain model.
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Colton, Dan. "An archaeological and geomorphological survey of the Luangwa Valley, Zambia." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494162.
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The aim of this research was to develop an understanding of the geomorphological processes that have affected the archaeological record in the South Luangwa National Park area of the Luangwa Valley, in eastern Zambia, and determine the extent to which genuine behavioural residues survive. Prior to this research little or no investigation had been initiated into Pleistocene and Holocene geomorphological processes, or the archaeological record.
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Viola, D., and A. S. McEwen. "Geomorphological Evidence for Shallow Ice in the Southern Hemisphere of Mars." AMER GEOPHYSICAL UNION, 2018. http://hdl.handle.net/10150/627126.
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The localized loss of near-surface excess ice on Mars by sublimation (and perhaps melting) can produce thermokarstic collapse features such as expanded craters and scalloped depressions, which can be indicators of the preservation of shallow ice. We demonstrate this by identifying High Resolution Imaging Science Experiment images containing expanded craters south of Arcadia Planitia (25-40 degrees N) and observe a spatial correlation between regions with thermokarst and the lowest-latitude ice-exposing impact craters identified to date. In addition to widespread thermokarst north of 35 degrees N, we observe localized thermokarst features that we interpret as patchy ice as far south as 25 degrees N. Few ice-exposing craters have been identified in the southern hemisphere of Mars since they are easier to find in dusty, high-albedo regions, but the relationship among expanded craters, ice-exposing impacts, and the predicted ice table boundary in Arcadia Planitia allows us to extend this thermokarst survey into the southern midlatitudes (30-60 degrees S) to infer the presence of ice today. Our observations suggest that the southern hemisphere excess ice boundary lies at 45 degrees S regionally. At lower latitudes, some isolated terrains (e.g., crater fill and pole-facing slopes) also contain thermokarst, suggesting local ice preservation. We look for spatial relationships between our results and surface properties (e.g., slope and neutron spectrometer water ice concentration) and ice table models to understand the observed ice distribution. Our results show trends with thermal inertia and dust cover and are broadly consistent with ice deposition during a period with a higher relative humidity than today. Shallow, lower-latitude ice deposits are of interest for future exploration.
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Willis, Ian Craig. "The hydrological context and geomorphological significance of glacier motion : Midtdlsbreen, Norway." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239090.
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Davis, Alexander M. "Geomorphological evolution of propagating fault tips in extensional and compressional settings." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/11992.
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Jones, Arwyn Rhys. "Geomorphological mapping in arid environments using the Landsat Thematic Mapper data." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358274.
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D'Arcy, Mitchall. "Constraining landscape sensitivity to climate change using geomorphological and sedimentological approaches." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/28651.
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Climate exerts a profound control on the processes that shape landscapes and produce the sedimentary deposits with which we can interpret the Earth's history. However, we lack a complete understanding of how sensitive tectonically-active, eroding landscapes are to climate and climate change. How does a simple sediment routing system react to a change in rainfall rate? Can mountainous landscapes respond quickly enough to preserve a record of high-frequency climate changes, e.g., glacial-interglacial cycles? What effect does headwater glaciation have on downstream sediment characteristics? Can we quantify past climate changes using the sedimentological properties of terrestrial stratigraphy? Geologists lack complete answers to these questions, among many others. Theoretical work, using physical first principles and numerical models, has produced a range of hypotheses about landscape sensitivity to climate, but we now need empirical data to test and make sense of these ideas. This thesis therefore explores empirically how geomorphological and sedimentological records have responded to climatic gradients across time and space. In the first part of this thesis, the extent to which spatial climate gradients are recorded by the longitudinal geometry of river channels is investigated. I use a simple stream power erosion law to predict an inverse relationship between channel steepness and average precipitation rate, and then test this theory using data from a variety of study areas and two complementary analytical approaches. Climate is found to be an important control on river longitudinal geometry across a range of climatic and tectonic conditions, in a way that conforms to existing theoretical knowledge and also allows the climatic signal to be discriminated from tectonics. This work therefore demonstrates that a widely-used geomorphological measurement - the channel steepness index - is quantifiably sensitive to climate in tectonically-active areas, and these findings offer a new explanation for geographic variations in channel steepness that cannot be explained by tectonics alone. The second part of this thesis focuses on the sensitivity of simple mountain catchment-alluvial fan systems to climate changes associated with the last glacial-interglacial cycle, as expressed in the south-western United States. First, eight debris flow-dominated systems located in the south-eastern Sierra Nevada, California are examined. I establish a detailed chronostratigraphic model for these fan systems by building upon and integrating existing exposure age constraints reported by others, and additionally developing a new technique for estimating the ages of these fan deposits. This technique is based on calibrating the rate of enlargement of common weathering fractures observed in exposed surface boulders, which are shown to widen at a steady and predictable rate post-deposition, and can be used as reliable age indicators for > 100 ka at this location. Using the detailed temporal record of deposition established for these fan systems, a large ( > 30,000 particle) grain size data set that spans the last full glacial-interglacial cycle is examined. I demonstrate that debris flow grain size is a highly sensitive recorder of past climate changes, capturing the glacial-interglacial cycle as a sustained and high-amplitude time series with a rapid response timescale of < 10 ka. These debris flow deposits become significantly coarser-grained with warming and overall drying of the climate, and this thesis outlines quantitative reasons why this signal can be attributed to increasing storm intensity with warming. Finally, these debris flow-dominated systems are contrasted with two carefully-selected stream flow-dominated fan systems in Death Valley, California. Using measures of down-system grain size fining and a self-similarity model of sediment calibre, sediment flux estimates during arid interglacial and wetter glacial climate conditions are derived and compared. This study shows that a decrease in average rainfall rate of ~ 30 % produced a corresponding decrease in sediment flux of ~ 20 %. However, I also demonstrate the circumstances in which signal buffering due to incision and sediment recycling destroys this climate signal. Consequently, this thesis demonstrates both the causes and results of complexity in the relationship between climate change, geomorphology, and well-dated terrestrial sedimentary records. Ultimately, this is an expression of how sediment transport processes, tectonics, the magnitude-frequency distribution of rainfall, and other factors interact to generate different climate responses in different systems. Nevertheless, for both geomorphic and sedimentological records examined here, I demonstrate that the effects of climate can be quantified clearly: channel steepness can be quantified as a function of rainfall rate; debris flow sedimentology can be quantified as a function of storm intensity; and alluvial fan sedimentology in Death Valley can be quantified as a function of glacial-interglacial climate changes. Essentially, this thesis finds that terrestrial landscapes are sensitive to known climate changes in the recent geological past, and this result is profoundly important for improving our ability to decode geomorphic and stratigraphic archives effectively. The data and ideas within this Ph.D. research provide useful opportunities for (i) testing and updating our models of how sediment routing systems respond to climate, (ii) extracting quantitative information about past climates from the sedimentary record, and (iii) predicting the effects of future climate changes on the landscape.
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Walker, Gavin. "River channel response to flooding in western Scotland over the past 250 years." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262865.
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Mattivi, Pietro. "Remote sensing and geomorphological data in support of precision agriculture and forestry." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Precision agriculture and forestry require a great deal of spatial data, in order to study the heterogeneity in vegetation conditions. The acquisition of this information can help decision-making and site-specific operations. The final aim of these land management procedures is to meet production demand, reducing waste
and environmental impacts.
The amount of data requested is huge and their collection could be considerably expensive in time and money. However, some of this information can be extracted from ready available data source, which are Digital Terrain Models (DTMs) and spaceborne Remote Sensing. The aim of this work is to analyze these data and to study how they can be processed in order to obtain useful information for precision land management.
The potentialities of these data sources were tested on the Rio Sinigo catchment. This basin is located near the town of Merano, in the autonomous province of Bolzano, South Tyroly. The Rio Sinigo watershed has an extension of 35 km2 and it presents a variety of morphological features, that make it suitable for the
study.
The DTM was processed, using different FOSS GIS packages, to extract primary and secondary topographic indexes, and to perform hydrological analysis. Particular attention has been paid to the extraction of the secondary topographic attributes (TWI and Potential Incoming Solar Radiation), which operating principles were discussed in detail, highlighting their limitations and potentialities.
Satellite images from Sentinel-1 and Sentinel-2 were used to obtain information on the soil moisture spatial and temporal variations, and to identify different land covers and possible major changes in time of the basin vegetation.
The conducted study confirmed the wide range of applications and the potentiality that these data sources have. The obtained products represent good basic data to perform preliminary investigations, to plan targeted data collection and to start a multi-criteria analysis.
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Gustavsson, Marcus. "Development of a Detailed Geomorphological Mapping System and GIS Geodatabase in Sweden." Doctoral thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7222.
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This thesis presents a method for detailed landscape presentation. The method incorporates both fieldwork-based comprehensive geomorphological description and digital data handling and thus contributes in filling the gap between traditional geomorphological mapping and modern geomorphological studies performed in Geographic Information Systems (GIS).
The main part of the thesis relates to development of a new detailed geomorphological mapping system, constructed to be easy to use and yet present a large amount of geomorphological information. The legend of the mapping system has successfully been applied to various types of landscapes, mapped at various scales between 1:5,000 and 1:50,000 without any modifications needed. The information presented in the map is based on simple descriptive criteria and thus the subjectivity is kept low, which enables a broad field of usage. In parallel with the mapping system a GIS-based geomorphological database has been developed. The structure and data presentation of the new mapping system allows for easy transformation of the data to form part of this database. The selected format of the GIS database is the ESRI ArcGIS®, Personal geodatabase.
In the development of the geomorphological mapping system four field areas have been mapped in central (Bonäs, Risa and Liden) and northern Sweden (Tarfala). In addition the new legend has been adapted to a field area situated in Vorarlberg, Austria (Upper Gamperdona valley).
In relation to the Tarfala field area an added issue of the project has been to give insights in the effects of physical and chemical weathering on various rock types to see if this can be detected in materials and landforms. The results from this study point at that resistance towards weathering vary among rocks even though they are of same rock type.
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Lane, Natalie F. "The Geomorphological Development of the Cotswold Hills, southern England: A Tectonic Perspective." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487281.
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Scarp and Vale' topography is typified by the Cotswolds region with the present-day landscape being the aggregate of earlier tectonic movement and surface processes. The primary aim of this thesis is to disentangle these landscape components, the .feedbacks between them and their driving mechanisms. Modelling suggests that flexure, in response to denudational unloading, may account for ~35% of local Pleistocene relief. Shape-fitting, between the model and landscape observations, shows the local lithosphere to be relatively weak and the uplift to be spatially varying. River longitudinal profiles adjust to extrinsic variables, such as tectonic movement, base level change and climate fluctuation. Parametrisation of 66 Cotswold draining rivers revealed trends, in their concavity and steepness index, consistent with those of the modelled uplift. Similar trends were sought from geomorphic analysis of the fluvial sinuosity and basin hypsometry. There is a morphological control to channel sinuosity as it is found to be dependent upon flow orientation. A positive relationship is observed. between hypsometric integral and proposed uplift, for the dip-slope basins. The accumulated geomorphic evidence does not prove the flexure modelling results, however, they are consistent with it. Viscoelastic modelling calculates the rate of lithospheric relaxation. It predicts high ' initial uplift rates which decrease rapidly and the attainment of topographic equilibrium within ~2o-50 ka of unloading. This is significantly lower than the climate cycle duration of 100 ka. Linking this result with a terrace aggradation and incision model, a schematic model of landscape evolution is produced. This incorporates the regional background uplift, a fluctuating climate, and episodic incision to which there is a flexural feedback. It is concluded that the Pleistocene has experienced a number of 'incision - flexural uplift aggradation' cycles controlled temporally by the fluctuating climate.
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Eriksson, Bert. "The zoo-geomorphological impact of fossorial rodents in sub-polar alpine environments." Licentiate thesis, Uppsala universitet, Kulturgeografiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150807.
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The geomorphological impact of small fossorial mammals (adapted to digging and living underground), such as rodents can be significant, and both their direct and indirect effects may contribute to landscape formation. This thesis is based on empirical field studies of two burrowing rodent species in sub-polar environments, namely invasive House mice (Mus musculus) on sub-Antarctic Marion Island and Norwegian lemmings (Lemmus lemmus) in sub-Arctic Abisko. The spatial distribution, sediment displacements, impact on vegetation and microclimatic effects of the rodents are documented. Invasive mice and rats, introduced on sub-Antarctic Islands during the 19th century, lack natural enemies and are shown to have a significant direct and indirect geomorphic impact by direct sediment displacement, vegetation removal by burrowing, grazing and trampling and thereby exposing the sediments for rain, wind and frost processes. The geomorphic impacts of lemmings are comparatively more limited as they rely on natural hollows and snow cover for protection and do not burrow to the same extent as other fossorial rodents in cold regions. Lemmings are thus suggested to have little impact on landform integrity, but can affect vegetation composition. A comparison of the findings from this study with published data on seven other rodent species and other physical mass transfer mechanisms in sub-polar and alpine environments suggests that fossorial rodents are a significant and sometimes dominant geomorphic force in sub-polar and alpine environments. The geomorphic work by ground squirrels, ice rats, plateau pikas and zokors is shown to be in the same order of magnitude as solifluction and rock falls. In alpine and periglacial environments these rodents are considered to act as key-stone species and ecosystem engineers through the creation of landforms by dislocation and of soil and other impacts on soil properties, vegetation and ecosystem function
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Toone, Julia. "Geomorphological discontinuities and ecological organisation : a case study of the River Drôme." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/6620.
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River channel changes, and patterns of in-stream macroinvertebrate community organisation, are both well explored in alluvial channels. Less is known about the behaviour of mixed bedrock-alluvial rivers, and their patterns of macroinvertebrate community structure. In response to relatively recent, widespread acknowledgment that sustainable and holistic river channel management is best achieved by a strategy that accounts for large-scale controls on long-term channel behaviour, there is a clear need to identify how spatial and temporal variation in rates and patterns of channel adjustment constrain the long-term evolution of mixed bedrock-alluvial channels, and their in-stream macroinvertebrate ecology. The River Drôme in south-eastern France is a fascinating example of river channel change in response to a complex history of natural and anthropogenic disturbances. Previous work has documented a long-term trajectory of channel degradation, but a reach linking the upper and lower sections of the river has not been explored and is of particular interest because of its striking mixed bedrock-alluvial morphology. Over five kilometres the channel is characterised by abrupt changes in style and substrate that naturally divide the reach into six geomorphic zones. These indicate that long-term degradation is not a simple, linear evolution but a complex non-linear process. The distinct pattern of geomorphological zonation along this reach forms the central focus of this thesis, specifically in terms of its historical development, present-day macroinvertebrate community structure, and future evolution. The first part of this thesis documents decadal changes in channel morphology between 1948 and 2006 by using GIS to analyse eight series of high-altitude aerial photography. Field work in 2005 and 2006 was used to ground truth observations. Changes in longitudinal channel profile are derived from topographic surveys from 1928, 2003 and 2005. There have been modest overall amounts of channel constriction, narrowing and incision, but there is substantial spatial and temporal variability in these trends. The present-day configuration of wide alluvial, and narrow bedrock zones has developed in response to a particular sequence of natural and anthropogenic events, emphasising the importance of contingency and channel sensitivity to disturbance. The reach is located 200 m downstream from le Béoux, a tributary to the Drôme, and historical changes in this sub-catchment have been manifest in the long-term behaviour of the reach. A significant flood in 1978 is the likely catalyst of present-day zonation, which locked the reach into a geometry that has constrained subsequent channel adjustments. While zonation remained distinct as recently as 2006, there is evidence that the channel is now operating under different boundary conditions to those that produced and maintained zonation before 2001. It is clear that predictions of future changes in channel morphology require a long-term perspective of channel behaviour, patterns and connectivities through time. The second part of this thesis characterises the present-day macroinvertebrate community of the study reach. Previous work in alluvial channels has considered how discontinuity in channel morphology influences spatial variation in patterns of macroinvertebrate organisation, but this has not been extended to mixed bedrock-alluvial channels. Relatively few studies have considered how spatial differences in channel behaviour (rather than simply channel character) may drive macroinvertebrate community organisation. Associations between channel morphology and macroinvertebrate community structure were tested by fieldwork carried out under low-flow conditions in 2006. Fifteen quantitative surber samples were collected at each of 10 sites along the reach. Local habitat characteristics, including particulate organic matter, bed sediment grain size (surface and subsurface), water quality (conductivity, temperature, pH) and flow velocity (benthic and mean) were also measured. Results indicate that the mass of particulate organic matter and the diversity of both surface and sub-surface grain size influence patterns of macroinvertebrate community structure along the reach. It is also apparent that zone-scale differences in flow and sediment regime, and differences in lateral and vertical channel dynamics are important. Variation in the frequency and intensity of bedload dispersal, which is a result of zone-scale variation in channel bed structure, is a dominant control on spatial patterns of macroinvertebrate community structure. These dynamics are the product of, and maintained by, the particular geography and history of the study reach, emphasising the primacy of place and the importance of understanding how larger-scale morphological processes constrain smallerscale patterns of macroinvertebrate biodiversity. At present, there are plans to manage channel degradation, along the study reach and in downstream parts of the river Drôme, by restoring sediment supply to the channel. This will be achieved by the remobilisation of bedload in the Béoux sub-catchment and so it is likely that there will be future changes to the present-day morphology and macroinvertebrate community organisation in the study reach. Combining the findings of parts one and two, the third part of this thesis evaluates the likely impacts of this management strategy. It is suggested that if the channel is connected to its active floodplain, and receives a sufficient external supply of bedload, then the reach-scale dynamic of zonation is self-regulating. Successful management intervention relies upon an understanding of this behaviour. Compared to predominantly bedrock and predominantly alluvial sections of the reach, the mixed bedrock-alluvial mid-reach supports significantly more diverse macroinvertebrate communities and higher proportions of EPT taxa. These characteristics are a function of the morphological diversity of the mid-reach, which results from the particular configuration and the connectivity of the present-day zones. It is considered that if future bedload supply to the channel is not deficient or excessive to present-day flow and sediment regimes, then the present-day morphological diversity of the reach could be maintained. This would also maintain present-day patterns of macroinvertebrate community structure. It is, therefore, hypothesised that if the reintroduction of bedload from the Béoux secures the reach with a moderate volume and frequent supply of sediment, then this drip feed would be a desirable management strategy.
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Hasan, Abed M. T. "The geomorphological history of the Gebel Al Akhdar valleys, North-eastern Libya." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243772.
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Styles, Jonathan. "The application of stereoscopic SPOT-HRV data and DEMs to geomorphological mapping." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292712.
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PINTO, RODRIGO WAGNER PAIXAO. "GEOMORPHOLOGICAL LANDSCAPE EVOLUTION OF THE GRANDE RIVER: DISSECTION DYNAMICS AND DRAINAGE CAPTURE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27097@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A análise dos sistemas fluviais são de extrema importância na compreensão da evolução geomorfológica da paisagem, pois possuem características, seja no seu arranjo ou distribuição dos canais, que permitem elaborar os episódios que ocorreram ao longo do tempo. A quebra do continente Gondwana e seus múltiplos eventos até a consolidação do Rift Continental do Sudeste (RCS) implicou em uma mudança significativa no relevo sudeste e, consequentemente, nos sistemas de drenagens. Isto promoveu a reorganização dos sistemas de drenagens e uma nova dinâmica hidro-erosiva pelo rebaixado do nível de base na porção leste do continente com a consolidação do RCS. Diante do exposto, selecionou-se como estudo de caso a bacia do Rio Grande no Rio de Janeiro com o objetivo principal de entender o processo de evolução geomorfológica da bacia, a partir da organização da rede de drenagem e feições elementares da bacia frente aos eventos geológicos de formação e estruturação do substrato rochoso. A metodologia utilizada se baseia em trabalhos de gabinete, de campo e posterior análise dos dados gerados. Estes procedimentos visaram compreender a evolução do relevo na bacia do Rio Grande com base na correlação entre aspectos geológicos e geomorfológicos na organização do seu sistema fluvial. Pode-se inferir que a evolução geomorfológica da bacia do Rio Grande foi influenciada pelos múltiplos eventos tectônicos até a consolidação do RCS. Os dados demonstram forte controle do substrato rochoso na morfologia do relevo e na orientação da rede de drenagem. Os resultados das orientações dos fluxos de drenagem demonstram grande quantidade de rios nas orientações NE e NW. Acredita-se que a região correspondeu a um extenso planalto de altitude mais elevada que a atual, e sistema fluvial com direção predominante para noroeste/norte. A evolução da bacia do Rio Grande se deu através do avanço das drenagens atlânticas sobre o antigo Planalto Sudeste, através da erosão remontante e controladas pelo nível de base.
Analysis of river systems are very important in understanding the geomorphological evolution of the landscape because they have characteristics, either in your arrangement or distribution channels, which enable the development of the episodes that have occurred over time. The break of the Gondwana Continent and its many events to the consolidation of Southeast Continental Rift resulted in a significant change in Southeast relief and hence the drainage systems. This promoted the reorganization of drainage systems and a new hydro-erosive dynamic by lowered the base level in the eastern portion of the continent with the consolidation of the Cenozoic RCS. Given the above, it was selected as a case study the basin of the Grande River in Rio de Janeiro with the main objective to understand the process of geomorphological evolution of the basin, from the drainage network organization and basic features of the front basin to events geological formation and structure of the bedrock. The methodology is based on office work, field and subsequent analysis of the data generated. These procedures were aimed at understanding the evolution of relief in the Rio Grande basin based on the correlation between geological and geomorphological aspects of the organization of its river system. It can be inferred that the geomorphological evolution of the Grande River basin was influenced by multiple tectonic events to the consolidation of RCS. The data demonstrate strong control of bedrock in relief morphology and orientation of the drainage system. The results of the guidelines of drainage flows demonstrate large number of rivers in the NE and NW directions. It is believed that the region corresponded to an extensive plateau higher than the current altitude, and river system with predominant direction north-west / north. The evolution of the Rio Grande basin was through the advancement of the Atlantic drainages on the old Plateau Southeast, through remontant erosion and controlled by the basic level.
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Gorney, Rebecca Michelle. "The Geomorphological and Ecological Conditions of a Lower Midwestern Coldwater Stream System." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1213101699.
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Cabral, Mariza Castanheira de Moura da Costa. "Effects of spatial constraints on channel network topology : implications for geomorphological inference /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10147.
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Ebert, Karin. "Cenozoic landscape evolution in northern Sweden : geomorphological interpretation within a GIS-framework /." Stockholm : Department of Physical Geography and Quaternary Geology, Stockholm University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-30711.
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Diss. (sammanfattning) Stockholm : Stockholms universitet, 2009.At the time of the doctoral defence, the following papers were unpublished and had a status as follows: Paper 2: In press. Paper 3: Manuscript. Paper 4: Manuscript. Härtill 4 uppsatser.
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May, Jan-Hendrik. "Late quaternary paleoenvironments of Eastern Bolivia deduced from geomorphological and paleopedological archives /." [S.l.] : [s.n.], 2007. http://www.zb.unibe.ch/download/eldiss/07may_j.pdf.
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Rocheford, Mary Kathryn. "Determining geomorphological and land use effects through physico-chemical fingerprinting of soils." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4735.
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The purpose of this project is to develop a framework for quantifying and differentiating the effects of early historic land uses on characteristics of soils formed in loess at two historical archaeology sites in the Midwestern United States: New Philadelphia Historical Landmark (NPHL) in western Illinois and Plum Grove Historical Farmstead (PGHF) in eastern Iowa. The significance of this research to topics such as global climate change, the role of soils in the carbon and nitrogen cycles, the effects of land use on sustainable use of soils, and augmenting the historical record by revealing land use activities for areas that have limited record of past land use are presented in the Introduction. The Introduction also includes reviews of previous geochemical studies and studies of natural and anthropogenic effects on the physical and chemical properties of soils. Research efforts were conducted in three main phases and the results of each phase are presented as individual chapters herein. Phase one focuses on identifying physico-chemical signatures of land use effects on soils at NPHL and determining the minimal resolution required to discriminate these effects to develop a multi-prong methodological framework. Phase two is an exploration of the efficacy of using portable x-ray fluorescence to measure non-pollution level chemical impacts from land use activities in order to refine the methodological framework by targeting soil samples for more costly, higher precision analyses. Phase three is a test of the refined framework to examine land use effects on physico-chemical characteristics of soil at PGHF. In the Summary and Conclusions the physico-chemical results from NPHL and PGHF are compared and contrasted to evaluate the methodological framework and its utility for investigation of land use effects at other Midwestern locations. The final section discusses possible revisions to the approach and outlines opportunities for future investigations.
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Beck, Tanya M. "Tracking Sediment Bypassing, Geomorphological Analysis, and Regional Sediment Management at Tidal Inlets." Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7741.
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Tidal inlets on sandy shorelines separate barrier islands and serve as a conduit for transport of sand and water between embayments and oceans, seas, or other tidally influenced waterbodies. Tides and waves induce currents along the coastline that transport sediment across-shore and alongshore. Coastal managers must optimize barrier-inlet system stability while conserving limited sediment resources, and often base management decisions and engineering design upon geomorphic and numerical models that predict the morphological behavior of tidal inlets on short-to-medium timescales (years to decades). The overall goal of this study was threefold. First, to provide science-based practical guidance for regional sediment management in the vicinity of tidal inlets. Secondly, to enhance the understanding of the temporal and spatial scales of sediment pathways in these regions through numerical simulation of traced sediment transport. And, third, to combine these lessons learned in both regional sediment management and analysis of morphodynamic and sediment bypassing pathways with application to a common practical management practice of inlet shoal mining and adjacent beach placement.
The temporal and spatial scales controlling the morphodynamics of barrier-inlet systems were reviewed within a regional sediment management context. Next, the application of regional sediment management methods to case studies of multiple barrier-inlet systems in West-Central Florida led to the development of a decision-support tool for regional sediment management (RSM) as applied to barrier-inlet systems. Connecting multiple barrier islands and inlets at appropriate spatio-temporal scales is critical in developing an appropriately scoped sediment management plan for a barrier-inlet system. Evaluating sediment bypassing capacity and overall inlet morphodynamics can better inform regional sand sharing along barrier-inlet coastlines; particularly where sediment resources are scarce and a close coupling between inlet dredging and beach placement is vital to long-term sustainable management. Continued sea-level rise and anthropogenic activities may intensify the need for investigating longer-term processes and expanding regional planning at a centennial timescale, and are acknowledged as challenging tasks for RSM studies going forward. A regionally focused, multi-inlet study was necessary to improve the management plans for the case study inlets (from north to south): John’s Pass, Blind Pass, Pass-a-Grille Inlet, and Bunces Pass. Key recommendations based on the case studies include: 1) allow the natural sediment bypassing to be re-established at Blind Pass inlet through reduced ebb-tidal delta mining, 2) reduce the interruption to sediment bypassing at John’s Pass and Pass-a-Grille inlets through an improved design of the dredged mining areas located along sediment bypassing pathways, 3) allow for continued natural sediment bypassing at Bunces Pass, and, 4) incorporate the cyclic sediment bypassing through swash-bar attachment into the management plan at Bunces Pass and adjacent barrier-islands. Similar systems in other regions may benefit from the lessons derived in this case study of an adaptively managed multi-inlet system.
A numerical model that computes hydrodynamics, sediment transport, and morphodynamics including bed layering was incorporated in this study to analyze sediment transport pathways between littoral sources from adjacent beaches and the geomorphic features of an idealized tidal inlet designed to imitate the John’s Pass tidal inlet in West-central Florida, USA. This study developed a methodology to numerically trace sediment transport, deposition and erosion. This method was applied to investigate sediment-bypassing pathways under varying temporal and spatial scales. The analyses of the adjacent beach’s contribution to tidal inlet sediment bypassing demonstrated variable temporal scales on sediment transport and exchange. High-energy wave events dominated the temporal scale for sand to be transported from the updrift beach to the ebb-tidal delta, whereas cyclical tidal processes had a significant influence on the spatial pattern of exchange between the shoals and channel features of the tidal inlet. The ability to simulate burial and erosion of tracers allowed identification of offshore sedimentation hotspots such as terminal lobe as well as zones of deposition and active transport in shallow water, such as the updrift channel margin linear bar and the downdrift platform of the ebb-tidal delta. The general sediment-bypassing pathway reflected a tidal-driven redistribution following event-driven pulses of wave-induced sediment mobilization. Sediment was transported along the beach during these energetic wave events. Flood- and ebb-tidal currents transported the sediment mobilized by high waves into the inlet channels. This was followed by subsequent gradual redistribution of the deposited channel sediments over the ebb-tidal delta features during fair-weather conditions.
The modeling methods were then applied to investigate the sediment pathways and bypassing processes for three validated numerical models of coastal tidal inlets that span a range of forcing conditions. The processes that influence sediment transport along various pathways between the several morphological features of each inlet and its adjacent beaches were examined. The sediment tracing methodology employed in this study allowed for an evaluation of the sediment transport pathways between the various morphologic features of a tidal inlet, as well as their respective processes that drive the exchange of sediments. Characterizing and correlating the sediment pathways between tidal inlet morphologic features can improve the inlet reservoir model, which is a predictive model of inlet shoal volumes based on empirical formulae. The results of this study illustrate the value of including sediment-tracking techniques in simulating sediment bypassing and the potential of this application to inform coastal engineering and design modifications to sediment reservoirs of tidal inlets.
And, finally, the spatial patterns of transport and erosion and deposition of traced, littoral source sediment, were investigated using the same modeling framework to evaluate the design of ebb-tidal delta mining on sediment bypassing dynamics of a tidal inlet system based on an idealized model of John’s Pass, Florida. Seven mining areas were simulated with traced sediment sources from the updrift beach, downdrift beach, and adjacent shoals. The tracers’ migration pattern and mining area infilling were analyzed to depict the sediment bypassing pathways and their contributions to mining area infilling. Mining area recovery rates were highest along the channel margin linear bar, and decrease offshore and downdrift. Updrift sand sources contributed more to mining area infilling than downdrift sand sources. The position of the mining area in relation to the updrift or downdrift morphological features dictates whether it will receive primarily updrift- or downdrift-originating littoral sediment from the beach. The source of sedimentation within the mining areas is a combination of inlet-ward transport of beach sediment and nearby shoal sediment. Proximity to the inlet channel determined the degree to which sedimentation had originated from longshore transported beach sediment. This methodology can improve confidence in management decisions concerned with the sand-sharing capacity of barrier-inlet systems in a local and regional context.
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O'Connor, Shoshannah. "A geomorphological study of the South Wellesley Islands, southern Gulf of Carpentaria." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/101891/4/Shoshannah_O%2527Connor_Thesis.pdf.
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This thesis details a geological history of the South Wellesley Islands, Southern Gulf of Carpentaria in Queensland, Australia over the mid- to late-Holocene. Field studies of the mixed bioclastic and siliciclastic coastal deposits on the South Wellesley Islands yielded significant data that was analysed in order to determine age constraints, the palaeo-depositional environment, rock composition and diagenetic history. The results of this research provide fundamental data for further work in producing a combined Holocene sea-level curve for the Southern Gulf of Carpentaria and the influence of sea-level change on the evolution of coastal environments in the tropical north of Australia.
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Shafei, Afshin. "Geomorphological characterization of fluvial flood hazard across the island of Oahu, Hawaii (USA)." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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Assessing floods hazard is critical to preventing damages and acting fast when a flood event occurs. Flood hazard assessment can be costly, time-consuming, and complex due to running complicated hydrodynamic models of rivers and floodplain systems. Besides, several model runs are normally necessary because different scenarios over large areas must be analyzed for a full characterization of flood hazards. To solve this problem and make the analysis easier with less cost and time, we can use machine-learning techniques. Machine-learning and data-driven methods can be the best alternative way to conventional methods because of their simplicity, faster processing, handling large amounts of data, and more importantly, learning from the past datasets and models to improve themselves. In this Thesis, data-driven DEM-based algorithms developed with the SaferPlaces project (funding: European Commission through EIT Climate-KIC) have been applied to analyze the fluvial and pluvial floods across Oahu island, USA.
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Lobera, Galán Gemma. "Eco-geomorphological dynamics in contrasting Mediterranean rivers with different degrees of flow regulation." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/401455.
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Aquesta tesi analitza l’efecte de les preses sobre el règim de cabals, el transport de sediments, la mobilitat de la llera, i la comunitat de macroinvertebrats en rius Mediterranis de la Península Ibèrica a diferents escales espacio-temporals. A gran escala espacio-temporal, els resultats mostren que la regulació modifica el règim de cabals reduint la magnitud i la freqüència de les crescudes. Aquest fet, juntament amb la disminució de l’aportació de sediments des d’aigües amunt, produeix una pèrdua de barres sedimentaries que són ocupades per la vegetació causant una ràpida estabilització la llera, limitant el dinamisme del riu i pot contribuir a la degradació de l’ecosistema fluvial. A petita escala (els rius Ésera i Siurana) es comprova que els embassaments retenen fins el 90% de la càrrega de sediment en suspensió, però l’aportació hídrica només es redueix en el cas de l’Ésera. En els trams d’aigües amunt, les partícules de la llera són mobilitzades de forma freqüent i s’observen canvis morfològics després de cada crescuda, mentre que els trams d'aigües avall es mantenen estables. En el cas del Siurana aquests canvis causen diferències notables en la composició taxonòmica dels macroinvertebrats, encara que la riquesa d’espècies es manté intacte. La densitat i la biomassa augmenten aigües avall però la biodiversitat disminueix. La tesi descriu i quantifica canvis en l’estructura bio-física i el funcionament de l’ecosistema fluvial en rius Mediterranis regulats i proporciona informació inèdita fins ara en el camp de la Eco-Geomorfologia.Esta tesis analiza el efecto de las presas sobre el régimen de caudales, el transporte de sedimentos, la morfología y la movilidad del cauce, y la comunidad de macroinvertebrados en ríos Mediterráneos de la Península Ibérica a diferentes escalas espacio-temporales. A gran escala espacio-temporal, los resultados muestran una reducción generalizada de la magnitud y la frecuencia de las crecidas que, juntamente con la reducción del suministro de sedimentos, produce una pérdida de barras que son ocupadas por la vegetación, hecho que estabiliza el cauce fluvial, limitando el dinamismo del lecho del río y puede contribuir a la degradación del ecosistema fluvial. En pequeña escala (los ríos Ésera y Siurana) se comprueba que los embalses retienen hasta el 90% de la carga de sedimentos en suspensión, aunque la aportación hídrica solo se reduce en Ésera. En los tramos de aguas arriba, las partículas del lecho son movilizadas frecuentemente y se observan cambios morfológicos después de cada crecida, mientras que los tramos de aguas abajo se mantienen estables. En el Siurana, estos cambios provocan diferencias significativas en la composición taxonómica de los macroinvertebrados en el Siurana, aunque la riqueza de especies se mantiene prácticamente intacta. Por otro lado, la densidad y la biomasa aumentan aguas abajo pero la biodiversidad disminuye. La tesis describe y cuantifica cambios en la estructura bio-física y el funcionamiento del ecosistema fluvial en ríos Mediterráneos regulados y proporciona información inédita en el campo de la Eco-Geomorfología.
The effects of dams on river flow regimes, sediment transport, channel morphology, bed mobility and macroinvertebrate communities were studied in Mediterranean rivers of the Iberian Peninsula at multiple temporal and spatial scales. At the large spatio-temporal scales, results show that regulation changes their flow regimes, with a generalized reduction in flood magnitude and frequency. This, in addition to the decrease in downstream sediment supply, results in the loss of active bars as they are encroached by vegetation (channel stabilization). Geomorphic stabilization limits riverchannel dynamics and may contribute to the environmental degradation of the fluvial ecosystem. At the small scale (the Ésera and the Siurana rivers), the reservoirs trap up to 90% of the suspended load, although total runoff is only reduced in the Ésera. In the upstream reaches, riverbed material is frequently entrained and morphological changes were observed following floods, while the downstream reaches were stables. In the Siurana, damming causes significant differences in taxonomic composition of the benthic invertebrate communities, but the species richness remained almost the same. Density and biomass increase notably below the dam although diversity decreases. The thesis describes and quantifies changes on the bio-physical structure and functioning of the fluvial ecosystem in dammed Mediterranean rivers and provides comprehensive insights in the field of the Eco-Geomorphology.
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Dunham, Mark Neville Edward. "The geomorphological nature and age of the linear escarpments of northeastern Eyre Peninsula /." Adelaide, 1992. http://web4.library.adelaide.edu.au/theses/09SB/09sbd917.pdf.
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Thesis (B. Sc.(Hons.))--University of Adelaide, Dept. of Geology and Geophysics, 1992.On title page : "National Grid reference S1-53 6331 and 6332 1 : 100 000 series. Includes bibliographical references (leaves 40-43).