Dissertations / Theses: 'Catchment geomorphology'

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Rubensdotter, Lena. "Alpine lake sediment archives and catchment geomorphology : causal relationships and implications for paleoenvironmental reconstructions." Doctoral thesis, Stockholm : Department of Physical Geography and Quaternary Geology, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-945.

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Thompson, Chris J. Physical Environmental &amp Mathematical Sciences Australian Defence Force Academy UNSW. "The geomorphology of Southeast Australian mountain streams." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Physical, Environmental and Mathematical Sciences, 2006. http://handle.unsw.edu.au/1959.4/38681.

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This thesis is a study of the morphology and sediment transport dynamics of mountain streams in southeast Australia. Mountain streams represent important geomorphological and ecological systems in Australia which have hitherto been poorly studied. The variability of mountain stream reach morphology was investigated at the regional scale using topographical surveys and sediment sampling techniques. Study sites were stratified by slope and local lithology. Eight channel-morphologies including Bedrock, Cascade, Step-pool, Planebed, Pool-Riffle, Cascade-pool, Riffle-step and Infilled, were identified using an objective statistical approach. Overall, channel types were found to correspond to existing reach-scale mountain stream templates. Five morphologies were associated with a specific lithology type which controlled the size and shape of grains supplied to the channels. Differences in coarse sediment transport processes between morphologies were investigated using stream monitoring techniques and Optically Stimulated Luminescence (OSL) dating. Monitoring results from a 3 year period indicated that channel beds are resistant to entrainment with shear stress thresholds for bedload transport ranging between 64 to 74 N/m2. Transport of reach median grain sizes requires floods that exceed bankfull discharge. Existing competence equations were found to over-predict the hydraulic driving force and consequently, a modified entrainment model was used to account for the regional channel characteristics. OSL dating was investigated as a tool to provide data on long-term sediment transport processes. Minimum age model results from the OSL dates show overall agreement with a selected entrainment model, and indicate differences in sediment transport dynamics between some reach morphology types. A regime model was used to quantify the physical domains of different channel morphologies. Limitations of the model were overcome by modifying the sediment supply surrogate to better reflect the dominant transported bedload size. Morphology types were delineated according to different sediment transport capacity-sediment supply domains. The distribution of channel morphology types within a series of catchments in southeast Australia was modelled within a GIS platform using the diagnostics of reach morphology derived from this study. The model provides a conceptual framework to evaluate the potential link between channel form, potential habitat diversity and aquatic biodiversity within the channel network in mountain streams.

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Boggs, Dimity. "Playas of the Yarra Yarra drainage system, Western Australia." University of Western Australia. School of Earth and Geographical Sciences, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0074.

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This thesis examines playas as integrated ecosystems, through investigation of long- and short-term processes associated with playa geomorphology, hydrology and diatom ecology, in playas of the Yarra Yarra drainage system of Western Australia. This landscape approach was conducted at a range of scales and consequently revealed a level of heterogeneity not previously described in Australian playas. The key result and common thread linking the three facets of the playas investigated is the importance of hydroperiod in defining the playa environment. The morphology and distribution of playas are described and the results presented of an examination of potential mechanisms determining intra-system variability. Measurements of the physical attributes of the playas, including length, area, shape, density and orientation, were made through Geographic Information System analysis and detailed interpretation of aerial photography. Two main morphological groups are distinguished: small (<10 ha), elliptical to circular playas with a NNW-SSE orientation; and large (>30 ha), elongated playas. Regional patterns in geomorphic attributes are markedly different between the west and east sides of the system. The boundary between the two regions coincides approximately with rainfall distribution. In this respect, climate is an overarching driver of geomorphological variation but sub-catchment characteristics are also critical determinants. Littoral drift and segmentation processes that are common to coastal lagoons but not commonly described in playas were identified from visual interpretation of aerial photographs of spits, bars and cuspate shorelines. Six small playas, representing an hydrological continuum from mostly wet to mostly dry, were selected for investigation of their hydrology and diatom ecology, enabling assessment ii of the variability of hydrology, hydrochemistry and of the effects of different hydrological environments on the distribution of taxa. Hydroperiod was highly variable and central to determining playa geomorphology and biology. In the six playas it ranged from 19 to over 211 days, and filling frequency from 1 to 3 cycles between 2002 and 2004, reflecting rainfall and sub-catchment variability. Monitoring a series of nested piezometers revealed that the playas were net discharge points for ground water over the period of survey. However, small local vertical head variations indicate ground water does not discharge at the same rate across the playa surfaces and that playas may have short-lived phases of ground water recharge. Hydrochemically, the playas are typical of salt lakes in Australia. They displayed a wide range of salinity values, neutral to alkaline pH and ionic composition similar to sea water. It is postulated that the geochemical evolution of waters in the playas follows a pathway where low salinity recharge waters with dilute sea water salts progress to Na-Cl dominated brines through evaporative concentration. Surface waters showed an ionic dominance consistent with sea water with minor variations attributed to transitional phases in the geochemical evolution of the waters. Shallow ground waters showed a common and consistent pattern of ionic dominance: Na+ >Mg2+ >K+ >Ca2+ : Cl- >SO4 2- >HCO3 ->CO3 2-.

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Anorov, Julie Margaret, and n/a. "Integrated Study of Coastal Wetland Characteristics and Geomorphic Processes in a South East Queensland Catchment." Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060223.153104.

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Coastal wetlands are dynamic ecosystems that are highly susceptible to change due to natural and human factors. The study area, located within the Native Dog Creek sub-catchment of the Logan River - which drains into Moreton Bay, south east Queensland - holds a detailed history of environmental change spanning most of the Holocene epoch. This history is preserved in the estuarine sedimentary record and is a valuable indicator of natural environmental change. More recently, human-induced changes within the study area have been superimposed on the natural process of environmental change. In order to develop a conceptual bio-geomorphic model of the coastal wetlands of Native Dog Creek, this thesis examined - on an integrated catchment basis - the evolution and connectivity of four coastal wetland community types (Melaleuca, Casuarina, saltmarsh and mangroves). The research consisted of four discrete studies within the study area: a geomorphic investigation that provided a framework for understanding how the wetlands evolved during the Holocene epoch; an acid sulfate soil (ASS) study that surveyed the distribution and concentration of sulfides; a palynological study that examined the natural directions of ecosystem change; and an investigation of the impact of specific human activities on these ecosystems. Detailed stratigraphic modelling found that the Logan River system (and its Native Dog Creek sub-catchment) has evolved from an infilling estuary since the peak of the Holocene transgression 6500 years before present. Recognition of the major controls that influenced geomorphic coastal development during the Holocene, provided important insights into the distribution and genesis of estuarine pyritic sediments which strongly influence the soils within the study area. In general, the estuarine central basin and fluvial delta sediments posed the greatest risk to the environment from acidification if disturbed. The major focus of the ASS study was to survey the distribution of ASS and to identify other areas most vulnerable to acidification. A predictive approach that combined chemical and stratigraphic analysis was used. Results showed that these areas are intrinsically related to their environment of deposition. The study found, for example, that the alternation of excessively wet and dry conditions - combined with high organic carbon levels and variations in microtopography - provided ideal conditions for the re-formation of pyrite in the stream channel within the Melaleuca wetlands. The palaeo-environmental study reconstructed the evolution of Holocene coastal wetland vegetation during the marine transgression and subsequent shoreline progradation. Pollen records from the four representative wetland communities (previously mentioned) were examined. The results found the mid-late Holocene vegetation history was controlled by the development of geomorphic features that have affected freshwater input, drainage and salinity. In response to the progradation of the shoreline after sea level stabilised, changes in fossil pollen from mangroves and saltmarsh taxa during the early-mid Holocene, to freshwater taxa during the late Holocene, are estimated to have taken 800 years. Thus, pollen analysis when used in combination with stratigraphic modelling, provided an important point of reference for rates of natural ecological change in response to evolutionary changes to the physical environment. The wetlands within the study area have suffered varying degrees of disturbance since European settlement in the 1820s. The most significant changes occurred during early European settlement, when vast areas of coastal lowlands were cleared for timber, sheep and cattle grazing and for agricultural purposes. A second period of change occurred from 1989 to 1995, when the Melaleuca community suffered dieback in response to hydrological modifications to Native Dog Creek for the development of a golf course. Results indicate that human-induced changes over the past 170 years have occurred at a rate far beyond the ability of the natural ecosystem to adapt or move to a more ecologically sustainable state, at least in the short-term. Hence the current environment is experiencing degradation through both decline in health and loss of indigenous species. The development of a conceptual bio-geomorphic model was based on the integration of results from all four studies, in an effort to provide a holistic understanding of the coastal wetland environment and of the impact of human-induced changes upon that environment. If these vulnerable ecosystems are to be maintained, successful and sustainable coastal management strategies must rely on a sound scientific understanding of the response of a coastal ecosystem to both human and environmental changes.

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Anorov, Julie Margaret. "Integrated Study of Coastal Wetland Characteristics and Geomorphic Processes in a South East Queensland Catchment." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/365955.

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change due to natural and human factors. The study area, located within the Native Dog Creek sub-catchment of the Logan River - which drains into Moreton Bay, south east Queensland - holds a detailed history of environmental change spanning most of the Holocene epoch. This history is preserved in the estuarine sedimentary record and is a valuable indicator of natural environmental change. More recently, human-induced changes within the study area have been superimposed on the natural process of environmental change. In order to develop a conceptual bio-geomorphic model of the coastal wetlands of Native Dog Creek, this thesis examined - on an integrated catchment basis - the evolution and connectivity of four coastal wetland community types (Melaleuca, Casuarina, saltmarsh and mangroves). The research consisted of four discrete studies within the study area: a geomorphic investigation that provided a framework for understanding how the wetlands evolved during the Holocene epoch; an acid sulfate soil (ASS) study that surveyed the distribution and concentration of sulfides; a palynological study that examined the natural directions of ecosystem change; and an investigation of the impact of specific human activities on these ecosystems. Detailed stratigraphic modelling found that the Logan River system (and its Native Dog Creek sub-catchment) has evolved from an infilling estuary since the peak of the Holocene transgression 6500 years before present. Recognition of the major controls that influenced geomorphic coastal development during the Holocene, provided important insights into the distribution and genesis of estuarine pyritic sediments which strongly influence the soils within the study area. In general, the estuarine central basin and fluvial delta sediments posed the greatest risk to the environment from acidification if disturbed. The major focus of the ASS study was to survey the distribution of ASS and to identify other areas most vulnerable to acidification. A predictive approach that combined chemical and stratigraphic analysis was used. Results showed that these areas are intrinsically related to their environment of deposition. The study found, for example, that the alternation of excessively wet and dry conditions - combined with high organic carbon levels and variations in microtopography - provided ideal conditions for the re-formation of pyrite in the stream channel within the Melaleuca wetlands. The palaeo-environmental study reconstructed the evolution of Holocene coastal wetland vegetation during the marine transgression and subsequent shoreline progradation. Pollen records from the four representative wetland communities (previously mentioned) were examined. The results found the mid-late Holocene vegetation history was controlled by the development of geomorphic features that have affected freshwater input, drainage and salinity. In response to the progradation of the shoreline after sea level stabilised, changes in fossil pollen from mangroves and saltmarsh taxa during the early-mid Holocene, to freshwater taxa during the late Holocene, are estimated to have taken 800 years. Thus, pollen analysis when used in combination with stratigraphic modelling, provided an important point of reference for rates of natural ecological change in response to evolutionary changes to the physical environment. The wetlands within the study area have suffered varying degrees of disturbance since European settlement in the 1820s. The most significant changes occurred during early European settlement, when vast areas of coastal lowlands were cleared for timber, sheep and cattle grazing and for agricultural purposes. A second period of change occurred from 1989 to 1995, when the Melaleuca community suffered dieback in response to hydrological modifications to Native Dog Creek for the development of a golf course. Results indicate that human-induced changes over the past 170 years have occurred at a rate far beyond the ability of the natural ecosystem to adapt or move to a more ecologically sustainable state, at least in the short-term. Hence the current environment is experiencing degradation through both decline in health and loss of indigenous species. The development of a conceptual bio-geomorphic model was based on the integration of results from all four studies, in an effort to provide a holistic understanding of the coastal wetland environment and of the impact of human-induced changes upon that environment. If these vulnerable ecosystems are to be maintained, successful and sustainable coastal management strategies must rely on a sound scientific understanding of the response of a coastal ecosystem to both human and environmental changes.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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Valters, Declan. "Modelling catchment sensitivity to rainfall resolution and erosional parameterisation in simulations of flash floods in the UK." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/modelling-catchment-sensitivity-to-rainfall-resolution-and-erosional-parameterisation-in-simulations-of-flash-floods-in-the-uk(a97f0c18-1222-42db-8ff9-daadfd3c9780).html.

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The contribution of this thesis is twofold: 1) the development of a hydrodynamic landscape evolution model for use on high-performance computing systems and 2) assessing the sensitivity of hydrogeomorphic processes to high-resolution rainfall input data and erosional parameterisation using the model. The thesis addresses a limitation in numerical landscape evolution models regarding how spatial variation in rainfall is represented or parameterised within such models. Typically, landscape evolution models forsake a realistic representation of rainfall patterns in favour of a simpler treatment of rainfall as being spatially homogeneous across the model domain. This simplification of rainfall spatial variability is still made despite the fact that many geomorphological processes are sensitive to thresholds of sediment entrainment and transport, driven by the distribution and movement of water within the landscape. The thesis starts by exploring current limitations in rainfall representation in landscape evolution models, and assesses various precipitation data sources that could be potentially used as more realistic rainfall inputs to landscape evolution models. A numerical model of landscape evolution is developed for deployment on high-performance parallel computing systems, based on the established CAESAR-Lisflood model (Coulthard et al., 2013). The new model code is benchmarked, showing performance benefits compared with the original CAESAR-Lisflood model it is based on. The model is applied to assessing the sensitivity of flood-inundation predictions, sediment flux, and erosion distribution within river catchments to spatial variation in rainfall during extreme storm events. Two real storm events that caused localised flash flooding in the UK are used as test cases: the Boscastle storm of 2004 and the North York Moors storm of 2005. Flood extent predictions and river discharges are found to be sensitive to the use of spatially variable input rainfall data, with high-resolution rainfall data leading to larger peak flood discharges. However, the differences are less pronounced in smaller catchments. The role of sediment erosion during large floods is also assessed, but it is found to play a minor role relative to spatially variable rainfall data. In contrast, the geomorphological response of catchments to single storm events is shown to be less sensitive to the spatial heterogeneity of rainfall input and controlled more strongly by the choice of erosional process parameterisation within the model. Nonetheless, spatial variability in rainfall data is shown to increase sediment yields during flash flood simulations.

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Afolabi, Olamide. "Quantitative characterisation of channel sinuosity, determination of catchment and sedimentary basin controls on channel sinuosity and interpretation of channel planform in fluvial systems with GIS and remote sensing techniques." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=226793.

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

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dos, Santos Toledo Busarello Mariana. "Machine Learning Applied to Reach Classification in a Northern Sweden Catchment." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184140.

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An accurate fine resolution classification of river systems positively impacts the process of assessment and monitoring of water courses, as stressed by the European Commission’s Water Framework Directive. Being able to attribute classes using remotely obtained data can be advantageous to perform extensive classification of reaches without the use of field work, with some methods also allowing to identify which features best described each of the process domains. In this work, the data from two Swedish sub-catchments above the highest coastline was used to train a Random Forest Classifier, a Machine Learning algorithm. The obtained model provided predictions of classifications and analyses of the most important features. Each study area was studied separately, then combined. In the combined case, the analysis was made with and without lakes in the data, to verify how it would affect the predictions. The results showed that the accuracy of the estimator was reliable, however, due to data complexity and imbalance, rapids were harder to be classify accurately, with an overprediction of the slow-flowing class. Combining the datasets and having the presence of lakes lessened the shortcomings of the data imbalance. Using the feature importance and permutation importance methods, the three most important features identified were the channel slope, the median of the roughness in the 100-m buffer, and the standard deviation of the planform curvature in the 100-m buffer. This finding was supported by previous studies, but other variables expected to have a high participation such as lithology and valley confinement were not relevant, which most likely relates to the coarseness of the available data. The most frequent errors were also placed in maps, showing there was some overlap of error hotspots and areas previously restored in 2010.

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Warman, Craig S. "Understanding the spatial and temporal variation in anthropogenically induced channel response in the Irwin River catchment." University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0214.

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

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Mohammed, Abdel-Fattah Sayed Soliman. "Integrated Hydro-geomorphological Approach to Flash Flood Risk Assessment and Mitigation Strategies in Wadi Systems." Kyoto University, 2017. http://hdl.handle.net/2433/227604.

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Ecrepont, Stéphane. "Analyse des effets d'échelle, d'organisation spatiale et de structuration géomorphologique pour la modélisation des débits et de flux hydrochimiques en bassins non jaugés." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1B007/document.

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La connaissance des dynamiques hydrologiques et du transport chimique associé est indispensable à la mise en place de stratégies de gestion de l’eau et du territoire, mais elle est difficile à consolider pour tous les exutoires de bassins versants porteurs d’enjeux car ils sont souvent « non-jaugés ». A partir d’un hydrogramme observé à l’exutoire d’un bassin jaugé, l'inversion d’un modèle hydrologique à base géomorphologique rend accessible la variable pluie nette en pied de versant. Cette variable indépendante d'échelle est ensuite transposée vers un bassin non-jaugé similaire et reconvoluée en hydrogramme à son exutoire. Cette méthode de "transposition d'hydrogramme", est appliquée pour la première fois en régime pluvio-nival dans 21 bassins Québécois. Le succès de la simulation pour le couple de bassins « jaugé » et « non-jaugé » est conditionné par la similarité hydrologique, soit l’ensemble des caractéristiques assurant un fonctionnement proche entre bassins versants. Nous testons si la composition chimique de l’eau est susceptible de révéler cette similarité à l’aide d’une analyse de type spectral développée sur l’ouest de la France, à l’échelle synoptique. Des groupes de bassins versants se démarquent par une homogénéité / hétérogénéité spatiale des faciès de concentrations, et de l’aire à partir de laquelle est observée la stabilisation de ce faciès. Ceci suggère que la composition chimique des rivières est informative d’un fonctionnement hydrologique similaire. Cette hypothèse est ensuite validée grâce à la transposition avec succès sur six bassins de méso-échelle des hydrogrammes et des relations concentrationdébit (CQ), les meilleurs résultats étant obtenus lorsque le couple respecte une similarité hydrochimique. Enfin, le couplage des hydrogrammes et des relations CQ a permis de prédire efficacement, grâce au principe de similarité, les flux en bassin versant non-jaugé, au pas de temps de 15 minutes
The knowledge of hydrological and hydrochemical dynamics is essential for policy makers to develop appropriate policies of remediation, but this goal is hard to achieve in « ungauged catchments ». Through the inversion of a geomorphology-based hydrological modelling, the net rainfall entering the stream network is assessed from a gauged catchment. This net rainfall is scale independant and can be convoluted in another (ungauged) catchment. This method is applied for the first time in a pluvio-nival context on 21 catchments from Québec. Success of the simulation depends of the hydrological similarity between gauged and ungauged catchments, which is defined as the ensemble of caracteristics insuring a close functionning. We test how riverwater chemical composition reveals this similarity through a synoptic spectral analysis developped on western France. Groups of catchments are identified by their spatial homogeneity/heterogeneoty of the hydrochemical facies, and the area at which hydrochemical stabilisation occurs. This result suggest that riverwater chemical composition is informative of a hydrological similarity. This hypothesis is successfully tested on six mesoscale catchments, by transposing hydrographs and concentration discharge relatioships (CQ), best transpositions are associated to similar catchments. Finally, the coupling of hydrological simulation to CQ curves allowed the prediction of hydrochemical fluxes in ungauged catchments with a 15 minutes timestep

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Rutherford, Jasmine Lee. "The role of geology, geomorphology, climate and vegetation, in controlling spatial and temporal changes in groundwater discharge from weathered crystalline basement aquifers in southwestern Australia." University of Western Australia. School of Earth and Geographical Sciences, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0006.

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[Truncated abstract] The Collie River drainage basin is an important water resource catchment in southwestern Australia. Salinisation of a major water supply within the catchment, the Wellington Reservoir, has arisen due to changes in the water and salt balance in response to land clearing over saprolite aquifers. Paired catchment studies, the Collie Experimental Catchments (CECs), established in the early 1970’s in high and low rainfall areas increased our understanding of water and salt (predominantly chloride) movement in these aquifers through the collection and analysis of high resolution spatio-temporal data. However, the conceptual models developed from this work take little account of landscape heterogeneity, and this has caused problems in subsequent modelling studies, where success in calibrating stream flow has been countered by difficulties in predicting salt loads. The challenge remains to better describe variability in the Collie landscape and understand the influence of climate, vegetation, geology and geomorphology on observed water and salt fluxes. The release of salt from the lower saprolite aquifer and the role of the surficial aquifer in buffering groundwater discharge were investigated. The acquisition, analysis and interpretation of new regolith and geophysical data in 2001-2003 from the CECs, together with data from a high resolution digital elevation model, and existing drilling information, were used to construct a geologicalgeomorphological compartment framework, to observe changes in aquifer behaviour ... Significant differences in the salt flux from compartments have been noted at a range of scales, with implications for both water resource and land management. The approach developed to identify compartments and assess their efficiency could be simplified, using catchment critical parameters determined from geological and geomorphological characteristics. As a consequence, the implementation of a compartment framework in catchments with saprolite aquifers should allow for more informed decisions to be made in the selection of sites for revegetation strategies or the development of engineering works. This is particularly important in the Collie Catchment where reclamation scenarios are currently being discussed. Consideration of the catchment as a compartmentalised system would help manage salt loads in the Collie River and return the Wellington Reservoir to a functional water resource.

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Bragança, Mário Teixeira Rodrigues. "Superfícies de erosão do setor centro-oriental da Bacia do Rio Paracatu, no Estado de Minas Gerais." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-29082012-091211/.

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A regularidade do relevo da bacia hidrográfica do rio Paracatu, inserida no Escudo Atlântico, preserva uma coluna estratigráfica em suas condições originais de deposição e com registros de movimentos crustais de pequena dimensão. Por isso, bucou-se associar a evolução da geomorfologia da bacia do rio Paracatu aos materiais e estrutura, na busca da compreensão da evolução do relevo da área; para tanto, foram consideradas as sucessões sedimentares, discordâncias e patamares erosivos, condição necessária para identificar e descrever padrões geomórficos regulares na paisagem. Revisão da bibliografia geológica e geomorfológica, manipulação da cartografia geológica e topográfica e sua integração e tratamento em SIG, a construção de perfis topográficos a partir de um modelo digital de terreno e campanhas de reconhecimento de campo nortearam os trabalhos, levando à identificação e descrição de quatro superfícies erosivas que registram as marcas da evolução geomorfológica regional: Superfície de Planaltos Tabulares, Superfície de Planaltos Tabulares com Vales Encaixados, Superfície de Planaltos Baixos com Pedimentos Ravinados e Vales Encaixados e Superfície da Depressão da Planície Fluvial do Rio Paracatu, ponto de convergência da reconstituição da história geomorfológica da área de estudo, resultando na composição de um mapa de superfícies de erosão.
The regularity of the relief of Paracatu Catchment inserted into Atlantic Shield, is preserved in weathering and erosion resistant rocky layers. It is organized in a stratigraphic column wich keeps its original conditions of deposition with recordings of small dimension crustal movements, allowing the ideal theoretical conditions for the study of erosion surfaces. To associate the evolution of geomorphology of Paracatu River Catchment to material and structure, looking for explanations to the preservation of erosion surfaces in the arrangement of sedimentary successions, unconformities and erosive plateaus were the conditions to identify and describe four surfaces wich record the regional morphological evolution: Tabular Plateau Surface, Tabular Plateau Surface with Dissected Valleys, Low Tableland with Ravined Pedments and Dissected Valleys Surface, and Paracatu River Fluvial Plain Depression Surface. A broad fieldwork through a general and regional approach, followed by an intense bibliographic review and manipulation of topographic and geologic maps and its manipulation in GIS, through a development of a Digital Terrain Model and many topographic profiles, allowed to describe the relief in suggesting the reconstitution of the geomorphological history of the study area, resulting in an erosion surfaces map. The origin of this erosion surfaces can be correlated to four tectonic cycles, that elevated the Brazilian Platform since the Cretaceous until Pleistocene, with drainage incision and dissection of the landscape.

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Abancó, i. Martínez de Arenzana Clàudia. "Monitoring and geomorphologic characterization of debris flows at catchment scale." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/128677.

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Debris flows are very fast mass movements and are considered as one of the most hazardous phenomenain mountainous regions. Research on this field has strongly improved during the last decades. However,many open questions remain concerning the details of the triggering mechanisms of this type of phenomena and their dynamic behaviour; both of them key points in the hazard assessment. The global purpose of this work is to improve some aspects of the debris-flow hazard assessment atcatchment scale; particularly the estimation of the events¿ magnitude, the determination of their intensity and the characterization of the triggering factors. Most of the objectives have been carried out by means of the auscultation of a catchment in wich the debris flows are frequent. Furthermore, data of geomorphological characterization of other catchments have been analysed. This work aims at increasing the knowledge on debris flows in the Pyrenees. In the context of this thesis, a debris-flow monitoring system has been set up in the Pyrenees, in the Rebaixader torrent (Alta Ribagorça, Central Pyrenees). Since July 2009, six debris flows involving volumes ranging from 1000 to 21000 m3, eleven debris floods (volumes from 350 to 2800 m3) and four rockfalls have been registered. The distinction between processes and the identification of the different phases of the flow events have mainly been based on ground vibration data. The detailed analysis of the ground vibration generated by torrential processes has revealed that there are several on-site factors strongly influencing the signal registered by the geophones. In particular, a significant decrease of the signal has been recognized at the geophones that were not placed close to the active channel. The ground vibration signal generated by some debris-flow events has not only been registered using the conventional digital sampling of the ground velocity signal, but also by means of transforming the ground velocity into impulses. Both techniques are suitable for the detection and characterization of the debris-flow events. However, the transformation into impulses shows interesting advantages, such as the low power consumption and the simplicity of the analysis of this type of signal in comparison to the conventional one. Both aspects are crucial in early warning and alarm systems (EWAS). Besides, the characterization of the rainfalls in the catchment has revealed that the most common debris-flow triggering rainfalls in the Rebaixader torrent last around 2 hours and the critical hourly intensity value is around 15 mm/h. However, it has been detected that also spring episodes of moderate intensity, accompanied by the potential infiltration from snowmelt can trigger torrential flows and rockfalls. In particular, a detailed analysis of three rockfalls that occurred in spring is presented. Moreover, a methodology to estimate the entrainment of bed material in a debris-flow event is presented within this study. The methodology was based on the creation of a decision tree (applying data mining techniques) over a database of geomorphologic parameters, collected in the field and from a digital elevation model, which incorporates 110 reaches from 17 torrents. Finally, a general decision tree was proposed that should be calibrated and adapted, in order to widen its application to other catchments and climatic regions.

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Addy, Stephen. "Hierarchical controls on river channel morphology in montane catchments in the Cairngorms, Scotland." Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=135792.

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The character of montane channel morphology and associated hierarchical controls was investigated in the Dee catchment, Cairngorm Mountains, north-east Scotland. Montane channel morphology in Scotland is of considerable importance given its relatively undisturbed condition in a UK context, variety and for providing habitat for several important lotic species. Nine distinctive sub-catchments were chosen to investigate the linkages between landscape controls and channel morphology distribution. The distribution of channel morphology at the reach scale was mapped using an expanded version of a process-based classification system originally developed in the Pacific northwest, USA. Continuous mapping revealed a wide variety and irregular distribution of channel morphology that is influenced primarily by a suite of glacigenic valley bottom controls. Differences in channel morphology distribution were apparent between catchments reflecting the influence of unique landscape evolution histories. In addition, fifty reaches exhibiting a variety of morphology and associated geomorphic setting, were surveyed in the field to explore in more detail controls on channel morphology. The results generally confirm the relevancy of the typology in the region and the dominant control exerted by slope. However the importance of scale, local controls and the regional geomorphic context was also highlighted. Finally, GIS approaches to channel characterisation at the catchment scale were tested to assess their potential usefulness for catchment management applications. By using a combination of the previous results, GIS models were calibrated and tested to predict the distribution of channel type and Atlantic salmon spawning habitat. The accuracy of channel type predictions were compromised by the model criteria and quality of geospatial data used. However the potential utility of the spawning habitat model as a first order method for screening habitat suitability over large areas was demonstrated.

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16

Hutchinson, Simon Mark. "The use of mineral magnetic and radiometric measurements in the study of erosion processes and sediment sources in upland catchments." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277486.

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17

Hobley, Daniel E. J. "Dynamics of long term fluvial response in postglacial catchments of the Ladakh Batholith, Northwest Indian Himalaya." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4929.

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Upland rivers control the large-scale topographic form of mountain belts, allow coupling of climate and tectonics at the earth’s surface and are responsible for large scale redistribution of sediment from source areas to sinks. However, the details of how these rivers behave when perturbed by changes to their boundary conditions are not well understood. I have used a combination of fieldwork, remotely sensed data, mathematical analysis and computer modelling to investigate the response of channels to well constrained changes in the forcings upon them, focussing in particular on the effects of glacial remoulding of the catchments draining the south flank of the Ladakh batholith, northwest Indian Himalaya. The last glacial maximum for these catchments is atypically old (~100 ka), and this allows investigation of the response to glaciation on a timescale not usually available. The geomorphology of the catchments is divided into three distinct domains on the basis of the behaviour of the trunk stream – an upper domain where the channel neither aggrades above or incises into the valley form previously carved by glacial abrasion, a middle domain where the channel incises a gorge down into glacial sediments which mantle the valley floor, and a lower domain where the channel aggrades above this postglacial sediment surface. This landscape provides a framework in which to analyze the processes and timescales of fluvial response to glacial modification. The dimensions of the gorge and the known dates of glacial retreat record a time averaged peak river incision rate of approximately 0.5 mm/y; the timescale for the river long profile to recover to a smooth, concave up form must exceed 1 Ma. These values are comparable with those from similarly sized catchments that have been transiently perturbed by changing tectonics, but have never been quoted for a glacially forced basin-scale response. I have also demonstrated that lowering of the upper reaches of the Ladakh channel long profiles by glacial processes can systematically and nonlinearly perturb the slope-area (concavity) scaling of the channel downstream of the resulting profile convexities, or knickzones. The concavity values are elevated significantly above the expected equilibrium values of 0.3-0.6, with the magnitude controlled by the relative position of the knickzone within the catchment, and thus also by the degree of glacial modification of the fluvial system. This work also documents the existence of very similar trends in measured concavities downstream of long profile convexities in other transiently responding river systems in different tectonoclimatic settings, including those responding to changes in relative channel uplift. This previously unrecognised unity of response across a wide variety of different environments argues that such a trend is an intrinsic property of river response to perturbation. Importantly, it is consistent with the scaling expected from variation in incision efficiency driven by evolving sediment flux downstream of knickzones. The pervasive nature of this altered scaling, and its implications for fluvial erosion laws in perturbed settings, have significant consequences for efforts to interpret past changes in forcings acting on river systems from modern topography. I follow this by examining in detail the channel hydraulics of the Ladakh streams as they incise in response to the glacial perturbation. I present a new framework under which the style of erosion of a natural channel can be characterized as either detachment- or transport-limited based upon comparison of the downstream distribution of shear stress with the resulting magnitude of incision. This framework also allows assessment of the importance of sediment flux driven effects in studied channels. This approach is then used to demonstrate that fluvial erosion and deposition in the Ladakh catchments is best modelled as a sediment flux dependent, thresholded, detachment-limited system. The exceptional quality of the incision record in this landscape enables an unprecedented calibration of the sediment flux function within this incision law for three different trunk streams. The resulting curves are not compatible with the theoretically-derived parabolic form of this relation, instead showing nonzero erosion rates at zero sediment flux, a rapid rise and peak at relative sediment fluxes of less than 0.5 and a quasi exponential decrease in erosional efficiency beyond this. The position of the erosional efficiency peak in relative sediment flux space and the magnitude of the curve are shown to be both variable between the catchments explored and also correlated with absolute sediment flux in the streams.

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Misset, Clément. "The role of riverbed on suspended sediment transport dynamics in Alpine Catchments." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU020/document.

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Les grandes quantités de sédiments transportés par suspension dans les rivières alpines sont associées à d’importantes problématiques socio-économiques et environnementales telles que le transport de polluants, la dégradation des milieux aquatiques ou l’envasement des retenues hydroélectriques. Pour faire face à ces enjeux, il est nécessaire de mieux comprendre le rôle joué par le lit des rivières alpines sur la dynamique de ce transport. A partir de larges bases de données issues de la littérature et de nouvelles mesures de terrain, la première partie de cette thèse propose une étude à une échelle régionale de i) l’influence de la configuration des sources sédimentaires sur la variabilité du transport solide par suspension, ii) l’estimation de la quantité et de la disponibilité des particules fines dans le lit des rivières alpines et iii) l’analyse de la relation entre transport solide par suspension et mobilité du lit de ces rivières. Ces analyses montrent que la configuration du bassin versant en amont du point d’observation contrôle significativement la dynamique du transport solide par suspension observée en aval. De grandes quantités de sédiments fins sont en effet stockées dans les rivières alpines alluviales et il est ainsi possible de prédire une partie significative de leurs flux en suspension pour les forts débits à partir d’une modélisation de la mobilité de leurs lits. La seconde partie de la thèse teste ces résultats à une échelle locale. Pour cela, une campagne de mesures a été réalisée durant une saison complète de fonte sur un cours d’eau alpin typique, la Séveraisse. Un large panel de mesures directes et indirectes a été mis en œuvre pour mesurer la suspension, le charriage et les évolutions topographiques sur un tronçon de 3.5 km. Ces mesures confirment que les particules fines transportées par suspension interagissent fortement avec le lit dans ce type de tronçon morphodynamiquement actif. Ce dernier peut être perçu comme une zone tampon intermédiaire contrôlée par le forçage amont sédiments-débit liquide ainsi que par la mobilité et la morphologie de son lit
The large quantities of sediments transported as suspension in Alpine rivers are associated with important socio-economic and environmental issues such as pollutant transfer, aquatic habitat degradation or dam siltation. To address these issues, it is required to better understand the role of Alpine river beds on the dynamics of this transport. In the first part of this thesis, we use large datasets from the literature and new field measurements to investigate at a regional scale i) the influence of sediment sources configuration on suspended load variability, ii) the quantity and availability of fine particles in Alpine river beds and iii) the relation between suspended load and river bed mobility. These analyses show that the catchment configuration upstream the observation point can significantly control the suspended load dynamics observed downstream. This first part also shows that large quantities of fine particles can be stored in alluvial Alpine rivers. For these rivers and for high flow rates, it was possible to predict a significant part of suspended load based on riverbed mobility modeling. The second part of the thesis tests these results at a local scale. To do so, an important field campaign was performed during the entire melting season of a typical Alpine river, the Séveraisse. A large panel of direct and indirect measurements was used to measure suspended load, bedload and topographic changes on a 3.5-km reach. These measurements confirm that suspended particles strongly interact with the river bed in that kind of morphodynamically active streams. The latter can be considered as an intermediate buffer controlled by the upstream hydro-sedimentary forcing and by the river bed mobility and morphology

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Howard, Susan Marie. "Relationship of headwater stream geomorphology to catchment geomorphology in the piedmont of North Carolina." 2007. http://www.lib.ncsu.edu/theses/available/etd-03192007-153119/unrestricted/etd.pdf.

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20

Wu, Huan-Ching, and 吳煥清. "On Fluvial Geomorphology of the Upstream Catchment of Hou-Lung River." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/94432851541624058018.

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碩士
中國文化大學
地學研究所
98
This study aims to explore the relationship between channel morphology, channel bed materials and the physiographic parameters of Dahu River catchment. Research materials include 1) cross-section profiles of the valley being abstracted from 1/5000 aerial photos, 2) channel bed gradient, 3) the hardness of rocks measured by Schmidt Hammer, 4) the particle distribution of river bed gravels, 5) physiographical parameters (such as drainage area) of the catchment being deduced from DEM by ArcGIS. The hardness of rocks, being measured by Schmidt Hammer, of geological units are well-correlated with those measurements done by others in literatures. This study leads to the following three conclusions. (1) 29 cross-section profiles are abstracted from 1:5000 topographic map along the main stream, and they are demonstrated by the cumulative area curves calculated along the elevation from the river bed upward. This form of the valley cross-section is mainly determined by its drainage area. (2) The channel bed gradient is mainly influenced by the strata orientation and the rock strength. In accordance with the flow direction and the inclination orientation of the strata formation, three situations can be defined 1) the subsequent type, 2) the vertical type, and 3) the obsequent type. Between them, the channel bed gradient of the obsequent type is highest. The channel bed gradient Only in the west section of the study area, the channel bed gradient shows a significant influence from the impact of the rock hardness. In general, the channel bed gradient is most affected by the geological structure. (3) The relation between the channel bed material and the geological regions is insignificant.

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21

Longmore, Jennifer Lyn. "The geomorphology of wetlands in the upper Mooi River catchment, KwaZulu-Natal." 2001. http://hdl.handle.net/10413/4518.

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Wetlands are now recognized as being an integral component of the physical landscape. Geomorphology has recently been recognised by wetland scientists as being of fundamental importance in wetland genesis, maintenance and evolution, thereby providing the context for informed, effective wetland management and conservation. At present there exists a paucity of geomorphological wetland research in South Africa. A hydro-geomorphic approach was adopted to attain an understanding of wetland genesis, distribution and functioning of a range of different palustrine wetland systems in the upper Mooi-River Catchment of KwaZulu-Natal. The physical, chemical and landscape-morphological characteristics of wetland soils were investigated to interpret the processes operating within those wetland systems. Both field and laboratory work suggest that wetland creation and maintenance in the upper Mooi River catchment may be attributed primarily to climatic factors, landscape position, landform and geological characteristics. These factors were found to cumulatively control the hydrological characteristics of wetlands, which impart an important influence on internal wetland conditions. While soil properties do not appear to be a primary factor in the establishment of these wetlands, they are nevertheless found to be important in the regulation of the hydrological dynamics of wetland systems. The close interdependence between wetlands and the surrounding landscape and the hydrological cycle is evident in the wetland systems investigated. Geomorphic processes within wetlands such as overbank flooding, overland flow, sedimentation, piping, leaching, soil swelling, shrinkage and cracking and channel incision and dynamics were found to be important variables in determining the nature and internal characteristics of wetland systems. In several of the systems investigated, all of the above mentioned processes were operative, while in other systems, a number of these processes were either insignificant or absent. Canonical Variate Analysis indicated that while commonalities exist between the palustrine wetland systems investigated in this study, significant differences were found between different groups. This supports the argument that a subclassification of the palustrine system into five different palustrine wetland types is warranted. While the scope of the present research did not allow for an extensive investigation of suitable methods of rehabilitation, the study suggests that an understanding of geomorphic process and wetland dynamics will be beneficial to wetland management and conservation as a whole.
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

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22

Favaro, ELENA. "Downstream Patterns and Catchment Controls on Suspended Sediment Transport in a High Arctic River." Thesis, 2013. http://hdl.handle.net/1974/8319.

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A study of downstream suspended sediment transport dynamics in the West River at Cape Bounty, Melville Island, Nunavut, was undertaken in 2012. The first component of the research quantified the sediment mobilized in the West River during the 2012 season. A nival bed-contact survey was undertaken to identify areas of the river in which stream flow was isolated from the bed, and was combined with a reach-based sediment budget approach to assess sediment entrainment and downstream movement. This analysis revealed the propensity of the West River to store suspended sediment through much of the season. Permafrost disturbances in 2007 inundated the West River with fine sediments, the majority of which are progressing from the headwaters as a sediment slug that is subject to substantial downstream storage. Diurnal and event hysteresis analysis from 2004-2012 demonstrate the change in sediment delivery inter-annually, transitioning from a system characterized by clockwise hysteresis prior to the 2007 disturbances, to counter-clockwise hysteresis post 2007. The latter is reflective of the important contribution of the headwater sediment slug from disturbance to downstream sediment transport and common net sediment storage in the lower reaches of the river. The second project studied the delivery of suspended sediment following late season major rainfall events (MRE) and the control antecedent catchment conditions prior to rainfall exert on the magnitude of stream runoff and suspended sediment transport. Two MREs on July 9 and July 23, totalling 35.4 and 10.6 mm, respectively, resulted in exceptionally low discharge response and sediment mobilization. Analysis of synoptic level pressure patterns and catchment soil moisture revealed low volumetric water content preceding both MREs, a result of sustained exceptional early summer warmth under stable regional high pressure. Compared to similar MREs in 2007-2009, the soil in 2012 did not become saturated, and substantial runoff did not occur. These studies contribute to an understanding of the processes of sediment transport in response to disturbances, rainfall, and antecedent catchment conditions, all of which are becoming important components of the Arctic fluvial systems but have had limited study due to the emphasis on snow melt processes and hydrological fluxes.
Thesis (Master, Geography) -- Queen's University, 2013-09-25 11:36:58.882

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23

Waclawik, Victor G. "Landscape evolution of the Umbum Creek Catchment, Western Lake Eyre, Central Australia." 2006. http://hdl.handle.net/2440/42833.

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Landscape evolution is important for mineral and petroleum exploration concepts, especially in dryland continental settings. This study seeks to understand the main issues and controls on landscape evolution that have produced the regolith and young sediments around the western side of Lake Eye, in the arid heart of Australia. Several methods were employed including satellite image analysis, geomorphometry, geological mapping, regolith mapping and surveying. Outcomes indicate that the underlying structural fabric of the basement has controlled the development of the surface morphology of the Umbum Creek Catchment. The arrangement of basement faults is reflected in the distribution of surface landforms and in the topography of the land surface. Significant deformation of the Etadunna and Eyre formations indicate tectonic activity occurred at the end of the Miocene and was probably related to movement in the Lake Eyre Fault Zone. Pleistocene faulting is expressed as minor blind faulting associated with pre - existing basement faults. These faults remain active and current seismic activity is driven by changes in hydrostatic pressure (hydroseismicity). The scale of Pleistocene faulting and modern seismic activity demonstrates that since the Pliocene tectonic activity has been subdued. Climate change caused landforms developed under wet conditions during the Palaeogene and Neogene to be preserved by the development of aridity in the Pleistocene. High erosion rates associated with tectonism and the onset of aridity in the Pleistocene led to topographic inversion of many features. Palaeo-Proterozoic inliers formed inselbergs, silcrete outcrops formed capstones, gypsum hardpans protected underlying sediment from erosion creating plateaux of gypsum patterned ground and palaeo-channels on the Neales Fan were eroded to make heavily armoured mounds and associated sand dunes and sand sheets. The dominant factor influencing the evolution of the landscape in the Umbum Creek Catchment was the deposition of sedimentary sulphides within the Bulldog Shale. The excess sulphur that this sediment supplied to the landscape over time created the necessary conditions for the formation of a range of landscape features that would not otherwise exist. Weathering, oxidation and leaching of the sedimentary sulphides led to the development of silcrete. Subsequent weathering and tectonic activity led to the breakdown of the silcrete and the distribution of silcrete pebbles widely across the landscape forming gibber plains. Sulphur from the Bulldog Shale continued to contribute to the landscape forming intra-formational gypsum and precipitating as gypsum hardpans. This study has implications for petroleum exploration in dryland continental settings as potential reservoirs may be affected by secondary diagenetic processes, such as the formation of gypsum or silcretes, that could act as baffles or result in reduced porosity within the reservoir. The broad-scale architecture of fluvial systems, like the Neales Fan, may not conform to traditional fan-shaped models being, instead, comprised of structurally rearranged channels. In terms of earthquake risk assessment, the identification of hydroseismicity active within the Lake Eye Basin allows for a new level of predictability of earthquake behaviour within Central Australia.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1260856
Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2006

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24

Waclawik, Victor G. "Landscape evolution of the Umbum Creek Catchment, Western Lake Eyre, Central Australia." Thesis, 2006. http://hdl.handle.net/2440/42833.

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Landscape evolution is important for mineral and petroleum exploration concepts, especially in dryland continental settings. This study seeks to understand the main issues and controls on landscape evolution that have produced the regolith and young sediments around the western side of Lake Eye, in the arid heart of Australia. Several methods were employed including satellite image analysis, geomorphometry, geological mapping, regolith mapping and surveying. Outcomes indicate that the underlying structural fabric of the basement has controlled the development of the surface morphology of the Umbum Creek Catchment. The arrangement of basement faults is reflected in the distribution of surface landforms and in the topography of the land surface. Significant deformation of the Etadunna and Eyre formations indicate tectonic activity occurred at the end of the Miocene and was probably related to movement in the Lake Eyre Fault Zone. Pleistocene faulting is expressed as minor blind faulting associated with pre - existing basement faults. These faults remain active and current seismic activity is driven by changes in hydrostatic pressure (hydroseismicity). The scale of Pleistocene faulting and modern seismic activity demonstrates that since the Pliocene tectonic activity has been subdued. Climate change caused landforms developed under wet conditions during the Palaeogene and Neogene to be preserved by the development of aridity in the Pleistocene. High erosion rates associated with tectonism and the onset of aridity in the Pleistocene led to topographic inversion of many features. Palaeo-Proterozoic inliers formed inselbergs, silcrete outcrops formed capstones, gypsum hardpans protected underlying sediment from erosion creating plateaux of gypsum patterned ground and palaeo-channels on the Neales Fan were eroded to make heavily armoured mounds and associated sand dunes and sand sheets. The dominant factor influencing the evolution of the landscape in the Umbum Creek Catchment was the deposition of sedimentary sulphides within the Bulldog Shale. The excess sulphur that this sediment supplied to the landscape over time created the necessary conditions for the formation of a range of landscape features that would not otherwise exist. Weathering, oxidation and leaching of the sedimentary sulphides led to the development of silcrete. Subsequent weathering and tectonic activity led to the breakdown of the silcrete and the distribution of silcrete pebbles widely across the landscape forming gibber plains. Sulphur from the Bulldog Shale continued to contribute to the landscape forming intra-formational gypsum and precipitating as gypsum hardpans. This study has implications for petroleum exploration in dryland continental settings as potential reservoirs may be affected by secondary diagenetic processes, such as the formation of gypsum or silcretes, that could act as baffles or result in reduced porosity within the reservoir. The broad-scale architecture of fluvial systems, like the Neales Fan, may not conform to traditional fan-shaped models being, instead, comprised of structurally rearranged channels. In terms of earthquake risk assessment, the identification of hydroseismicity active within the Lake Eye Basin allows for a new level of predictability of earthquake behaviour within Central Australia.
Thesis (Ph.D.) -- School of Earth and Environmental Sciences, 2006

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Legg, Nicholas T. "Debris flows in glaciated catchments : a case study on Mount Rainier, Washington." Thesis, 2013. http://hdl.handle.net/1957/38180.

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Debris flows, which occur in mountain settings worldwide, have been particularly damaging in the glaciated basins flanking the stratovolcanoes in the Cascade Range of the northwestern United States. This thesis contains two manuscripts that respectively investigate the (1) initiation processes of debris flows in these glaciated catchments, and (2) debris flow occurrence and its effect on valley bottoms over the last thousand years. In a 2006 storm, seven debris flows initiated from proglacial gullies of separate basins on the flanks of Mount Rainier. Gully heads at glacier termini and distributed collapse of gully walls imply that clear water was transformed to debris flow through progressive addition of sediment along gully lengths. In the first study, we analyze gully changes, reconstruct runoff conditions, and assess spatial distributions of debris flows to infer the processes and conditions necessary for debris flow initiation in glaciated catchments. Gully measurements suggest that sediment bulking requires steep gradients, abundant unstable material, and sufficient gully length. Reconstruction of runoff generated during the storm suggests that glaciers are important for generating the runoff necessary for debris flow initiation, particularly because infiltration capacities on glacial till covered surfaces well exceed measured rainfall rates. Runoff generation from glaciers and abundant loose debris at their termini explain why all debris flows in the storm initiated from proglacial areas. Proglacial areas that produced debris flows have steeper drainage networks with significantly higher elevations and lower drainage areas, suggesting that debris flows are associated with high elevation glaciers with relatively steep proglacial areas. This correlation reflects positive slope-elevation trends for the Mount Rainier volcano. An indirect effect of glacier change is thus the change in the distribution of ice-free slopes, which influence a basin’s debris flow potential. These findings have implications for projections of debris flow activity in basins experiencing glacier change. The second study uses a variety of dating techniques to reconstruct a chronology of debris flows in the Kautz Creek valley on the southwest flank of Mount Rainier (Washington). Dendrochronologic dating of growth disturbances combined with lichenometric techniques constrained five debris flow ages from 1712 to 1915 AD. We also estimated ages of three debris flows ranging in age from ca. 970 to 1661. Run-out distances served as a proxy for debris flow magnitude, and indicate that at least 11, 2, and 1 debris flow(s) have traveled at least 1, 3, and 5 km from the valley head, respectively since ca. 1650. Valley form reflects the frequency-magnitude relationship indicated by the chronology. In the upper, relatively steep valley, discrete debris flow snouts and secondary channels are abundant, suggesting a process of debris flow conveyance, channel plugging, and channel avulsion. The lower valley is characterized by relatively smooth surfaces, an absence of bouldery debris flow snouts, few secondary channels, and relatively old surface ages inferred from the presence of tephra layers. We infer that the lower valley is deposited on by relatively infrequent, large magnitude, low-yield strength debris flows like an event in 1947, which deposited wide, tabular lobes of debris outside of the main channel. Debris flows during the Little Ice Age (LIA) predominantly traveled no further than the upper valley. Stratigraphic evidence suggests that the main Kautz Creek channel was filled during the LIA, enhancing debris flow deposition on the valley surface and perhaps reducing run-out lengths. Diminished areas and gradients in front of glaciers during the LIA also likely contributed to decreased run-out lengths. These findings suggest that changes in debris flow source and depositional zones resulting from temperature and glacier cycles influence the magnitude and run-out distances of debris flows, and the dynamics of deposition in valley bottoms.
Graduation date: 2013

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Dissertations / Theses on the topic 'Catchment geomorphology'

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