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Warburton, Toni. "Catchment". Thesis, The University of Sydney, 2000. https://hdl.handle.net/2123/27946.
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Topological ideas have informed the imprinting moulding and folding of the membrane in my work with container objects. Pertinent aspects of previous work are recounted. Situations pertaining to water and glass as materials and content that relate to my project in contemporary art practice are examined. The ecological significance of water in swamplands focusses content in my work with ornament to evoke nature specific to situation or to place. Filtering metaphors have evolved through explorations of materials and structures.The motif of a water glass is used to invoke the sacred necessity of pure water.
Theories of ornament impinge on material investigations and the syntax of moulds. Agency in making and language of process required to work effectively with others to realise mould-blown pieces are investigated. The 'techniques of the body' applied to making and using are discussed with respect to mimetic and vernacular associations of the truncated conical beaker shape and placement and perception in installation practice.
Ideas that relate to materiality and residual function, difference and repetition, seek to conflate the vernacular and the uncanny. Hollowness, becoming and Chora, invoke processes and perturbations that I anticipate as catharthic resonance with respect to the visual and haptic experience of the viewer.
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Materechera, Fenji. "Towards integrated catchment management : challenges surrounding implementation in the Gamtoos River catchment". Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1018553.
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Water resource management has become a pertinent issue of global environmental concern in response to the conditions of a growing global population, increasing development and a limited freshwater supply. It is against the backdrop of such conditions that effective water resource management has gained popularity in seeking to ensure that the needs of the growing population will be met and secured for future generations. The notion of integrated water resource management (IWRM) is a perspective on water resource management that has evolved out of the global opinion that social and ecological systems are linked and therefore cannot be managed separately. The department of water affairs (DWA) in South Africa highlights the importance of approaching management of water resources from a catchment perspective which forms the basis for a particular integrated approach to management called integrated catchment management (ICM). ICM recognizes the catchment as the correct administrative unit for management. It integrates water resources and the land that forms the catchment area in planning and management. Researchers have described the implementation of ICM as being complicated and difficult. This is no exception to South Africa. Principles of ICM have received widespread prominence in South Africa as they have been incorporated into national water policy. Actual implementation however is still in its infancy. The study is therefore a case study of ICM with respect to factors influencing implementation amongst different stakeholders. The study aims to explore the theme of implementation of ICM within the context of the Gamtoos River Catchment with a view toward identifying and addressing challenges that may be more broadly applicable. The study adopts an inductive, exploratory approach to the connection between theory and practice. A systems-based framework characterized by sequential steps similar to that employed in a case study conducted by Bellamy et al. (2001) in Queensland Australia is used to facilitate the evaluation of ICM in the Gamtoos River Catchment. The evaluation is achieved through a three step process of exploration in the current study. Triangulation is applied to the choice of methods of analysis which involves the use of a global analysis method, the use of learning scenarios and a grounded theory method. Findings reveal seven core themes which help to provide a detailed, contextual understanding relating to the status quo for ICM in the catchment. Results from a grounded theory analysis summarized the main challenges to implementation into five broad categories. Based on this analysis method and the application of the three learning scenarios for the Gamtoos River Catchment, the extent to which these challenges exist was discovered. The state of ICM in the catchment was classified as falling within a condition of a level of success being achieved with room for improvement to a condition of optimal ICM. The study concludes that based on the context of ICM being an example of a Complex Adaptive Systems (CAS), this state of ICM in the Gamtoos River Catchment is subject to change. This therefore necessitates the consideration of approaches to implementation that are adaptive to change. Findings may serve to inform decision making on how ICM can be effectively implemented elsewhere in a South African context.
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Zanardo, Stefano. "Catchment-scale transport phenomena: rainfall intermittency, age of runoff, anthropic catchment management". Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3427400.
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Complexity of transport phenomena at the catchment scale arises from the interconnection of several processes over a range of spatial and temporal scales. The hydrologic and biogeochemical response of catchments is produced by the highly non-linear interaction between meteorological forcing, landscape heterogeneity, and human activity. As a result, a simple experimental analysis does not give significant insight into the processes involved and exploring such phenomena is a challenging task. Nevertheless, investigating these processes is important in order to evaluate the dominant controls on catchment-scale mechanisms as well as predict the response of the systems to human activities and climate-related perturbations. This is particularly relevant in changing environments, where a deep understanding of the systems is critical for a proper management of landscape and water resources. This thesis aims at exploring catchment-scale transport phenomena by applying novel modeling tools to relevant case studies. Both deterministic and probabilistic approaches are followed, as the latter are required by the random nature physical processes whereas the former allow for the analysis of the systems under certain, well defined conditions. Model evaluations are supported by robust analyses of extensive datasets, whose purpose is not simply to validate the approaches but rather to provide further insight into the processes. Long term effects of hydrologic fluctuations are captured by stochastic models in terms of steady state statistical distributions of relevant physical quantities. This modeling approach provides a causal relationship between daily rainfall random fluctuations and daily stream flow variability, this, in turn, relates to the variability of stream stage, and in-stream nutrients removal. The stochastic approach is further extended to evaluate the effect of the daily variability of precipitation on the inter-annual variability of water balance. The application of the model to a large amount of experimental catchment across the United States shows how there exist regions where the daily variability of water partitioning is the major control on inter-annual variability of water balance, and regions where the inter-annual variability arises from controls other than the simple scaling-up of short term processes. A deterministic approach, namely Mass Response Function (MRF), is used to evaluate the effect of soil heterogeneities, as well as the effect of water-mixing mechanisms on the hydrologic and biogeochemical response of catchments. The main idea underlying this framework is that the evolution of solute and water pulses moving within the soil largely depends on their residence time. The application of the MRF model to a tracer study on nitrates and lithium suggests that runoff is composed by a collection of water particles with a mixture of ages and that, in this case, the effect of unmixed preferential flow can be ruled out. The MRF is then coupled with a `source zone' model suitable to describe pesticides release from the top soil layer in intensively managed catchments. This additional module proves necessary to properly simulate the pesticides transport mechanisms. The application of the model to a decade-long water-quality monitoring dataset suggests that the prediction of the agro-chemical response requires an accurate knowledge of the management practices. In particular, the interval between the occurrence of large rainfall events and the pesticide application dates seems to constitute the main control on the pesticide release dynamics. These considerations are of particular interest when modeling pesticides as they are exclusively of anthropic origin. Whereas, when considering other types contaminant such as nutrients, the anthropic component may be clouded by the effect of chemical soil production.La complessità dei fenomeni di trasporto alla scala di bacino deriva dall'interconnessione di diversi processi su diverse scale temporali e spaziali. La risposta idrologica e biogeochimica dei bacini è il prodotto di interazioni altamente non lineari tra le forzanti meteorologiche, le eterogeneità del territorio e le attività umane. Di conseguenza, semplici analisi sperimentali non permettono un'adeguata comprensione dei processi coinvolti, e l'analisi di questi fenomeni rappresenta un obiettivo ambizioso. Tuttavia, l'esplorazione di questi processi è importante per valutare i controlli dominanti su meccanismi di trasporto alla scala di bacino e predirne la risposta idrologica e biogeochimica a perturbazioni climatiche ed alla gestione del territorio. Questo è particolarmente importante nel caso di ecosistemi in cambiamento, dove una profonda comprensione dei processi è fondamentale per una corretta gestione del territorio e delle risorse idriche. Lo scopo di questa tesi è l'analisi di fenomeni di trasporto alla scala di bacino attraverso l'applicazione di nuovi approcci modellistici a casi studio di interesse. A questo scopo si è utilizzato sia un approccio probabilistico sia un approccio deterministico: il primo richiesto dalla natura casuale di numerosi processi fisici coinvolti, il secondo necessario per analizzare le dinamiche sotto condizioni ben definite. Lo studio è supportato da una robusta analisi dei dati disponibili, il cui scopo non è semplicemente quello di validare i modelli ma piuttosto di fornire una comprensione più approfondita delle dinamiche in gioco. Gli effetti di fluttuazioni idrologiche nel lungo termine sono simulati attraverso distribuzioni di probabilità stazionarie relative a grandezze fisiche rilevanti. Questo approccio modellistico fornisce una relazione causale tra la fluttuazione giornaliera della pioggia e la fluttuazione giornaliera dei deflussi, la quale, a sua volta, è messa in relazione con l'atezza di moto nei corsi d'acqua ed infine con i processi rimozione di nutrienti nelle reti idrografiche. Tale approccio stocastico è successivamente utilizzato per valutare l'effetto delle fluttuazioni giornaliere delle precipitazioni sulla variabilità inter-annuale del bilancio idrico alla scala di bacino. L'applicazione del modello ad un esteso numero di bacini sperimentali, distribuiti sul territorio degli Stati Uniti, mostra come esistano alcune regioni dove le fluttuazioni della pioggia giornaliera rappresentano il controllo principale sulla la variabilità inter-annuale del bilancio idrico, ed altre regioni dove questa variabilità è determinata da altri processi che non necessariamente avvengono alla scala giornaliera. Un modello deterministico, detto Mass Response Function (MRF), è utilizzato per valutare l'effetto delle eterogeneità del suolo e dei meccanismi di mescolamento sulla risposta idrologica e biogeochimica dei bacini. Il concetto principale che caratterizza questo approccio si basa sull'assunzione che l'evoluzione degli impulsi di acqua e soluti che si muovono nel suolo sia prevalentemente governata dal relativo tempo di residenza. L'applicazione del modello MRF ad uno studio di traccianti effettuato utilizzando nitrati e litio suggerisce che i deflussi sono composti da un insieme di impulsi aventi differenti età e che, almeno nel caso in esame, l'effetto di flussi preferenziali non mescolati può essere trascurato. Il modello MRF è stato successivamente accoppiato con un modello detto `source zone' atto a simulare il rilascio di pesticidi dallo strato superficiale del suolo in bacini intensamente antropizzati. L'aggiunta di questo secondo modello si è dimostrata necessaria per rappresentare accuratamente le dinamiche di trasporto dei pesticidi. L'applicazione ad un caso di studio sperimentale suggerisce come la previsione della risposta agro-chimica richieda un'accurata conoscenza della pratiche agricole utilizzate. In particolare, l'intervallo tra la data di applicazione dei pesticidi e i primi eventi di pioggia successivi sembra costituire il fattore principale nelle dinamiche di rilascio di contaminanti. Queste considerazioni sono di particolare interesse nella modellazione dei pesticidi in quanto di origine esclusivamente antropica. Nel caso invece della modellazione contaminanti quali i nutrienti, la componente antropica può venire oscurata dalla produzione chimica del suolo.
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Mehl, Daniel James Gustav. "Assessing the influence of floodplain wetlands on wet and dry season river flows along the Nuwejaars River, Western Cape, South Africa". University of the Western Cape, 2019. http://hdl.handle.net/11394/7031.
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>Magister Scientiae - MScImproved knowledge is required on the quantity and source of water resources, particularly evident during periods of drought currently being faced in South Africa. There is inadequate knowledge with regards to the flood attenuating properties of wetlands, particularly evident in the ungauged catchments of Southern Africa. This study aims to improve the knowledge on the contribution of flow from tributaries with headwaters in mountainous regions to low lying areas and the effects of wetlands on river flow patterns. Several river flow monitoring sites were established along the major upper tributaries of the Nuwejaars River at which daily water levels were recorded and bi-weekly discharge measurements were conducted. Weather data was collected using four automatic weather stations and three automatic rain gauges’ setup throughout the catchment. Rainfall data coupled with rating curves and daily discharges were used to assess the flow responses of these tributaries to rainfall events. Additionally, stable isotope analysis and basic water quality analysis was used to determine the major sources of flow within the major tributaries. The rainfall and river flow data collected, coupled with the characterization of the wetland was used to determine the flood attenuation capabilities of the wetland. Lastly, a conceptual model based on a basic water balance was developed to further explain the role of the wetland and its effects on river flows. The results showed a 27-hour lag time in peak flows from the upper tributaries at the inflows of the wetland to the outflow. Two of the upper tributaries had flow throughout the year and were fed by springs in the upper mountainous regions of the catchment and all tributaries were largely reliant on rainfall for peak flows. The temporary storage of flows within the wetland occurred as a result of the Nuwejaars River bursting its banks, filling of pools, or ponds and the Voëlvlei Lake. It was concluded that the wetland increased the travel time and decreased the magnitude of flows of the Nuwejaars River. However, due to the fact that wetlands are interlinked on a catchment scale and have a collective effect on flood attenuation this study may be improved by looking at the wetlands within the catchment holistically.
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Shepherd, Christina. "Towards integrated catchment management : institutional arrangements : a case study of the Patawalonga catchment /". Title page, table of contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09ENV/09envs5478.pdf.
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Driscoll, Jessica Margit. "Impacts of Climate Change in Snowmelt-Dominated Alpine Catchments: Development and Assessment of Comparative Methods to Quantify the Role of Dynamic Storage and Subsurface Hydrologic Processes". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/560860.
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Snowmelt-dominated systems are a significant source of water supply for the Western United States. Changes in timing and duration of snowmelt are predicted to continue under climate change; however, the impact this change will have on water resources is not well understood. The ability to compare hydrologic processes across space and time is critical to accurately assess the physical and chemical response of headwater systems to climate change. This dissertation builds upon previous work by using long-term data from two snowmelt dominated catchments to investigate the response of hydrologic processes at different temporal and spatial scales. First, results from an hourly spatially-distributed energy balance snowmelt model were spatially and temporally aggregated to provide daily, catchment-wide snowmelt estimates, which, along with measured discharge and hydrochemical data were used to assess and compare hydrologic processes which occur on an annual scale in two headwater catchments for an eleven year study period. Second, the magnitude and timing of snowmelt, discharge fluxes and hydrochemical data were used to assess and compare inter-annual catchment response in two headwater catchments for an eleven year study period. Third, a pseudoinverse method was developed to compare mineral weathering fluxes in a series of nested sub-catchments over an eleven year study period. Advances from this work include the use of an independently-created energy balance snowmelt model for spatially-distributed hydrologic input for catchment-scale water balance, application of a quantifiable measure of catchment-scale hydrologic flux hysteresis and the development of a method to quantify and compare mineral weathering reactions between source waters across space and time. These methods were utilized to quantify and assess its role of dynamic storage in mitigating climate change response.
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Davidson, Celene. "Catchment diagnostic framework for the Klip River catchment, Vaal Barrage, October 1998 - September 1999". Thesis, University of the Witwatersrand, Johannesburg, 2003. http://hdl.handle.net/10539/21298.
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This research report is a completed Catchment Diagnostic Framework (CDF) for the Klip
River catchment (Johannesburg) for the period October 1998 to September 1999.
The framework consists of a catchment description and a diagnostic index which provide
a simple and representative view of the catchment and its characteristics and assist in
identifying problem areas.
GIS maps, graphs and tables are used to provide a background of the catchment. The
Diagnostic Index is based on a set of Indicators that are calculated and then scored
according to a rating system allowing for the calculation of an overall value for the
catchment. The indicators and description cover resource conditions, socioeconomics,
water quantity, water quality and management.
Using this CDF it was found that the Klip River catchment is highly altered due to
mining, urban, industrial and agricultural development. All of these have impacts on the
beneficial use of the Klip River itself and on the downstream users of the Vaal Barrage.AC 2016
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Lindblom, Karin. "PFAS in Gullspångsälvens catchment area". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-64608.
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Gullspångsälvens catchment area starts in the county of Dalarna and ends in the lake Vänern. On the way the water passes a couple of villages and small towns. The aim of the project is to identify point sources of PFAS and see their influence on the PFAS levels in the systems surface water. In the area some point sources have been identified. The villages and towns have waste water treatment plants and there are also a couple of landfills. Sampling have been carried out at expected point sources as well as in the surface water close to human activities. The samples have been extracted with SPE and analysed with LCMS-MS. Results show that the levels of PFAS is increasing through the system and that the expected point sources release PFAS to the environment. It was also possible to identify an earlier unknown point source. Compared with levels in other parts of Sweden (S-EPA, 2016) the levels of PFAS in the system is within a normal range except for the levels close to the until now unknown point source.
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Singh, Anupam K. "Towards decision support models for an ungauded catchment in India : the case of Anas catchment". Karlsruhe : Institut für Wasserwirtschaft und Kulturtechnik, Universität Karlsruhe (TH), 2004. http://www.ubka.uni-karlsruhe.de/eva/index.html.
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Higgins, David Ian. "Catchment scale influences on brown trout fry populations in the Upper Ure catchment, North Yorkshire". Thesis, Durham University, 2011. http://etheses.dur.ac.uk/3571/.
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A multi-scale approach for restoration site selection is presented and applied to an upland catchment, the River Ure, North Yorkshire. Traditional survey methods, advances in remote sensing, Geographical Information Systems (GIS) and risk-based fine sediment modelling using the SCIMAP module are combined to gather data at the catchment-scale through to the in-stream habitat-scale. The data gathered have been assessed against spatially distributed brown trout fry populations using Pearson’s correlation and multiple stepwise regressions. Fine sediment was shown to have a positive correlation with fry populations when upland drainage channels (grips) were added to the SCIMAP model. This suggests risk from peatland drainage is realised further down the catchment where eroded sediments are deposited. Farm-scale SCIMAP modelling was tested against farmers’ knowledge with variable results. It appears there is a cultural response to risk developed over generations. Management of meadows and pasture land through sub-surface drainage and stock rotation resulted in the risk being negated or re-routed across the holding. At other locations apparently low-risk zones become risky through less sensitive farming methods. This multi-scale approach reveals that the largest impacts on brown trout recruitment operate at the habitat-adjacent scale in tributaries with small upstream areas. The results show a hierarchy of impact, and risk-filters, arising from different intensity land management. This offers potential for targeted restoration site selection. In low-order streams it seems that restoration measures which exclude livestock, and provide bankside shading, can be effective. At such sites the catchment-scale shows a reduced signal on in-stream biota. Thus, brown trout stocks could be significantly enhanced by targeting restoration at riffle-habitat zones and adjacent land in order to disconnect the stream from farm-derived impacts and through adding structure to the stream channel.
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Abrahams, Ebrahiem. "Measurement and modelling of catchment erosion dynamics under different land cover types, Jonkershoek Catchment, Western Cape". University of the Western Cape, 2020. http://hdl.handle.net/11394/7292.
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>Magister Scientiae - MScSeveral attempts have been made to assess the impact of post-fire soil erosion; however, erosion occurs as a result of the complex interplay between many factors, such as climate, land cover, soil and topography, making precise estimation difficult. Additionally, these factors are far from constant in space and time, and often interact with one another. To assess the impact of wildfire on soil erosion and factors influencing its variability, the post-fire soil erosion response of two mountainous headwater sub-catchments namely Langrivier and Tierkloof, with different vegetation cover in the Jonkershoek Valley was examined using a systematic approach that combines efforts in field and laboratory work, spatial analysis and process-based numerical modelling. Geospatial modelling shows high spatial variability in erosion risk, with 56 % to 67 % of surfaces being highly susceptible excluding rock cover. The model highlights the importance of terrain and vegetation indices, with predicted erosion being more severe on steep slopes with lower vegetation cover.
2021-08-30
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Arnott, Sean. "An assessment of methods for catchment-scale identification of goundwater-suface water interractions in lowland permeable catchments". Thesis, University of Exeter, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532017.
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A better understanding f groundwater-surface water interactions is urgently required o underpin the implementation of the Water Framework Directive and to increase our knowledge of environmental processes in relation to base flow, chemical and nutrient fluxes, contaminated groundwater-surface water transfers, the selection of spawning sites by Atlantic salmon( Salmos alar) and the abstraction of groundwater. This project assessed a range of methods, other than the time-consuming technique of flow gauging, as fast and effective indicators of groundwater-surface water interactions over a catchment-wide scale.The study was aided by the results of two high resolution catchment-wide flow-accretion surveys. Physical and chemical tracers were shown to be ineffective when compared against the results of the flow-accretion surveys. A number of factors, such as long reach lengths, anthropogenic discharges, other in-stream processes and similar groundwater and surface water composition, appeared to diminish the signals produced by groundwater inputs to below detectable levels. A detailed reach-scale investigation assessed a range of methods over different temporal and spatial scales. The direct measurement of groundwater and surface water levels were 100% accurate in the identification of groundwater-surface water interactions, but this method would be impractical for catchment-scale assessment. Three methods for predicting groundwater-surface water interaction sites were assessed based on hydrogeological theory, such as groundwater flow systems, dry valley inputs and localised aspects of the solid geology. The effectiveness of the predictions were compared against the results of the Frome and Piddle flow-accretion surveys. The method using the localised aspects of the solid geology showed relatively high accuracy (60-70%)and was quite fast for catchment-scale assessment. The final investigation showed a statistically insignificant correlation between groundwater inputs and the location of Atlantic salmon( Salmos alar) redds. However, lower densities of Atlantic salmon redds were observed a long certain survey reaches that were subjected to surface water losses.
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Svensson, Teresia. "Chlorine Transport in a Small Catchment". Doctoral thesis, Linköping : Univ, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6316.
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Vincent, Craig Nicholas. "Hydrogeology of the Upper Selwyn Catchment". Thesis, University of Canterbury. Geological Sciences, 2005. http://hdl.handle.net/10092/1137.
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Farming practices within the upper Selwyn plains have significantly expanded, and are becoming more dependent on groundwater as a reliable source of irrigation. This expansion has resulted in the rapid development of the groundwater resource and water levels in many wells have reached record low levels. Groundwater resources can be found within at least three aquifers within the glacial gravel deposits of the upper Selwyn plains. Aquifer 1 occurs between approximately 0-30 m, aquifer 2 between 40-85 m and aquifer 3 greater than 100 m below the surface. Aquifers 1 and 2 occur within close proximity to the Selwyn River and its tributaries. Aquifer 1 is unconfined, aquifer 2 semi-confined and aquifer 3 semi-confined to confined. Significant leakage of groundwater occurs between the different aquifers. Recharge sources to the aquifers include rainfall infiltration and river seepage. Water levels and groundwater chemistry suggest that the Selwyn River provides the dominant source of recharge to aquifers 1 and 2 in areas immediately surrounding the river and to the south of the current course of the river between Greendale and Dunsandel.
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Granger, Erika C. "Water Quality Modeling in Kranji Catchment". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60762.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010."June 2010." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 50-52).
This thesis describes the process and results of applying the Soil and Water Assessment Tool (SWAT) to characterize bacterial fate and transport in the Kranji Catchment of Singapore. The goal of this process is to predict bacterial loading to Kranji Reservoir under the forcing of weather and other variables. Necessary data and input values were collected or estimated and input into the model. One of the most important of these values is the bacterial die-off rate. This rate must be accurate for the model to provide accurate predictions of bacterial loadings. In order to obtain a value for the bacterial die-off rate, an attenuation study was conducted. The results of this study were not typical. Bacterial growth was observed to occur during dark hours, and decay was observed to occur during sunlit hours. The resulting light and dark decay constants were combined for use in the model. The specific bacterial loading rates associated with the various agricultural activities occurring in the catchment are not available and thus were roughly estimated. Point source loadings were also estimated. Four years of model simulation daily output were analyzed, and results for specific subcatchments with differing character are discussed. This application of SWAT shows a good ability to make qualitative predictions of the presence or absence of bacteria; however, quantitative agreement between model predictions and field observations is poor. This run of the model is like a first draft-more refinement and more information are needed before it will make accurate predictions; however, the framework is in place.
by Erika C. Granger.
M.Eng.
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Sundström, Linn. "Investigating the impact of the Millennium Drought on catchment water balance : A study of four catchments in Victoria, Australia". Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231134.
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Southeast Australia have between 1997-2009 experienced a severe drought, referred to as the Millennium Drought. During these years the region experienced a 11.4% decline in mean annual rainfall, an unprecedented decrease in runoff and a decline in soil moisture and groundwater storage. The drought officially ended in 2010 when one of the strongest La Nina-events on record occurred. However, it is still unknown how the behaviour of the catchments changed during the drought and if this change persists in the years following the drought. Changes in catchment behaviour and fluxes are commonly determined using a catchment water balance, where the change in groundwater storage is assumed to be neglectable when studying longer periods of time. However, studies have showed that this assumption might be inaccurate for catchments that experience a climatic disturbance such as a severe drought. This study investigates if including the change in groundwater storage by using spatial groundwater head data can improve the catchment water balance. This was done by assuming that specific yields are unknown and to be determined in a calibration. An unknown scalar applied to the evapotranspiration was used to try to account for the uncertainties in the known fluxes and was also to be determined in the calibration. Two different calibration schemes were considered: one assuming no delay in groundwater head response to climate and one accounting for the delay. The fluxes were determined for the period before, during and after the drought. The results were analysed to determine if the catchments showed a change in behaviour during and after the drought. The results showed that when not accounting for the delayed response of the groundwater head, at least one of the specific yields in the catchments became infinitely small. Including the delayed groundwater head response did improve one of the catchments significantly by producing plausible specific yields for all geological units. A conclusion of this is that including the change in groundwater storage could improve the water balance. However, for it to do so a thorough analysis of the groundwater and subsurface needs to be conducted. Further, the water balance error was the third biggest flux after rainfall and actual evapotranspiration suggesting that the evapotranspiration scalar reduced the actual evapotranspiration too much. All fluxes did decrease during the drought, by how much differed between the catchments and the water balance components. Two of the catchments showed a change in behaviour during the drought that persisted in the years following the drought. The most likely fluxes to have caused this were the change in runoff and groundwater storage. The other two catchments showed a smaller change in behaviour during the drought and an indication that it was on its way back to the same state as before the drought. The likely fluxes to have caused the small change in behaviour was runoff and actual evapotranspiration.Under åren 1997–2009 minskade den genomsnittliga årliga nederbörden över sydöstra Australien med 11.4% och den genomsnittliga årliga avrinningen var lägre än någonsin tidigare samtidigt som grundvattennivåerna sjönk. Denna torka brukar kallas the Millennium Drought och är den svåraste torkan i Australien i modern tid. Torkan tog officiellt slut 2010 då ett av de mest kraftfulla La Niña-fenomenen inträffade vilket bidrog till att april 2010 till mars 2012 var de blötaste två åren i australiensk historia. Trots att flera studier har gjorts kring torkan så är det ännu inte klarlagts hur avrinningsområdena i området påverkades och om de fortfarande är påverkade när torkan officiellt är över. Flödena inom ett avrinningsområde bestäms vanligtvis genom en vattenbalans. Då vattenbalansen över ett avrinningsområde studeras under en längre tid antas ofta att förändringarna i grundvattenmagasinen går att bortse från då grundvattennivån ofta återgår till samma stadie efter ett antal år. Nyare studier har dock visat att detta inte alltid är fallet vid exempelvis en svår torka och att det vid dessa fall inte är korrekt att anta att förändringen i grundvattenmagasinen är försumbar. I denna studie har en vattenbalans gjorts för fyra avrinningsområden i delstaten Victoria i Australien. Syftet har varit att avgöra om vattenbalansen kan förbättras om förändringen i grundvattenmagasinen inkluderas. Detta har gjorts genom att använda nyligen framtagen data för grundvattennivån i delstaten och antagit att den dränerbara porositeten är en okänd variabel. För att justera för osäkerheterna kring the kända flödena har en okänd faktor för evapotranspirationen inkluderats. De okända variablerna bestämdes i en kalibrering. Kalibreringen genomfördes för två olika kalibreringsscheman och för tre olika tidsperioder. Det ena kalibreringsschemat antog att grundvattnet direkt reagerade på effektiv nederbörd minus avrinning, medan den andra kalibreringsschemat tog hänsyn till en försenad reaktion. Kalibreringen gjordes för tidsperioderna innan, under och efter torkan. Resultaten visade att när ingen hänsyn togs till en eventuellt försenad reaktion av grundvatten så går värdet för dränerbar porositet i minst en geologisk enhet mot noll medan det andra värdet är rimligt. När hänsyn togs till en försenad reaktion av grundvattnet, fick fler avrinningsområde rimliga värden för dränerbar porositet för hela området. Slutsatsen som kan dras kring detta är att vattenbalansen kan förbättras om förändringen i grundvattenmagasinen inkluderas. Detta kräver dock en djupgående analys av grundvattnet och geologin i avrinningsområdet. Hur mycket flödena förändrades under och efter torkan varierar mellan avrinningsområdena och flödena, gemensamt var dock att alla flöden minskade under torkan. Två av avrinningsområdena påvisade en förändring i beteendet under torkan och de år som följde. Det är mest troligt att förändringarna i avrinning och grundvattenmagasinen har påverkat detta. De övriga två avrinningsområdena påvisade även de en förändring under torkan, om än mindre än för de föregående. Denna förändring ser även ut att vara på tillbakagående och att avrinningsområdet inom en snar framtid skulle kunna ha samma tillstånd som innan torkan. De mest troliga flödena som har påverkat dessa avrinningsområden är förändringar i avrinning och den faktisk evapotranspirationen.
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Whelan, Michael John. "Numerical modelling of small catchment nitrogen dynamics with particular reference to the Slapton Wood catchment, South Devon". Thesis, University of Leeds, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343483.
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Jahandideh-Tehrani, Mahsa. "Development of an integrated catchment model framework for climate change impacts assessment: The Nerang River catchment, Australia". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/400453.
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Long lasting changes in all components of the climate system are expected to occur due to continuing greenhouse gas emissions and increasing human activities (IPCC, 2014). Extreme events, such as droughts and floods are predicted to be significantly affected by climate change. The vast and variable climate change impacts on hydrological regimes, water availability, floods, droughts, rainfall intensity and frequency confirm that current water resource planning and management must be adopted for efficient future planning, policy design, as well as sustainable water supply.
Evaluating climate change impacts has been an important issue in Australia, particularly in Southeast Queensland (SEQ) as this region is regarded as a “hot spot” in Australia, which is significantly affected by climate change. Additionally, in Australia, 1% change in the mean annual rainfall leads to 2-3% change in the mean annual streamflow (Teng et al., 2012). Therefore, there is a fundamental need to understand and analyse the potential changes in rainfall under climate change in catchments located in SEQ, as small rainfall changes will considerably alter the resulting hydrologic response of these catchments.
In order to properly consider uncertainty in the hydrological projections for catchments and to improve forecast accuracy under climate change scenarios, multi-model ensembles of General Circulation Models (GCMs) should be employed. Such an ensemble multi-model approach can potentially provide a range of possible future hydrological conditions, allowing water managers to consider integrated uncertainty and adaptation strategies.
The overall aim of this study was to develop a holistic understanding of the ensemble impacts of climate change and sea level rise on the Nerang River catchment, SEQ, Australia. This includes the development of an integrated catchment modelling framework for the catchment, which has proved to be a robust tool for understanding climate change impacts in SEQ. Additionally, such integrated catchment modelling framework provides in-depth understanding of the interaction between separate parts of a river system and catchment behaviour.
To achieve a holistic understanding of the catchment behaviour, the first part of this research was based on model establishment, including two hydrologic models (for both real-time and long-term river flow predictions), a reservoir operation model, and a hydrodynamic river model which were developed, calibrated and validated for the Nerang River catchment. After successful establishment of the stated models, the second part of this research focused on evaluating impacts of climate change on the hydrologic and hydraulic conditions of the Nerang River catchment using ensemble projections of eight GCMs and sea level rise.
The outcomes of the developed integrated modelling framework in this research equip decision makers with an efficient and easy-to-apply tool for evaluating different climate change scenarios to investigate adaptation strategies.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Näschen, Kristian [Verfasser]. "Impact assessment of global change on wetland-catchment interactions in a tropical East African catchment / Kristian Näschen". Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1207923427/34.
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Rehn, Lukas. "Temporal Trends in Dissolved Inorganic Carbon in a Swedish Boreal Catchment". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-435368.
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Inland waters are important systems for transforming, storing and transporting carbon along the aquatic continuum, but also by emitting carbon dioxide (CO2) and methane (CH4) to the atmosphere. In light of the last decades observed increase in dissolved organic carbon (DOC) in many inland waters across the northern hemisphere, a logical question arise whether other aquatic carbon species display similar trends. This study examined the measured concentrations of dissolved inorganic carbon (DIC) in a boreal catchment over a 14-year period. The objectives were to determine changes in DIC concentration over time and try to explain the causes for the observed changes. Data from 15 mostly forested sub-catchments were analyzed, both over the full time period, and grouped by season. Over the full 14-year period, only two of the sites exhibited significant trends in DIC concentration, both being negative. However, by seasonally grouping the data distinct patterns for the different seasons emerged. The autumn and winter data displayed no significant trends, whereas the spring flood data showed significant negative trends for almost all sites (14 out of 15). The summer data showed significant negative trends for seven sites, and positive for one site. The DIC concentration data were expectedly positively correlated with pH across most sites (13 out of 15). The correlation with DOC was negative for most sites (11 out of 15), possibly indicating different origins of the different carbon species. The DIC concentration was also negatively correlated with discharge for most sites (13 out of 15), suggesting a diluting effect with increased discharge. In conclusion, significant negative trends were observed during the spring flood and summer periods. Although the cause of these trends will require further investigation, the correlation analysis showed that the DIC concentration was closely related to the catchment hydrology. This suggests changes in terrestrial source areas where DIC is mobilized during spring and summer, and that these changes might continue during altered hydrometeorological conditions. The differences in DIC trends between sub-catchments further show the variability of the boreal landscape and highlight the need for local-scale process understanding when scaling to larger landscape units. We further conclude that trends in DIC concentration do not follow observed DOC changes over time, suggesting that DIC and DOC exports are mechanistically decoupled.
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Wallin, Marcus. "Carbon dioxide evasion from a boreal catchment /". Uppsala : Sveriges lantbruksuniversitet, 2005. http://info1.ma.slu.se/IMA/Publikationer/internserie/2005-18.pdf.
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Nelson, Tracy Jane. "Identifying sediment sources in the Tees catchment". Thesis, Durham University, 2003. http://etheses.dur.ac.uk/3684/.
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The main objective of this research is to identify the sources of suspended sediments in the River Tees. Earlier work in the Tees has focused on the extent of heavy metal concentrations in the river sediments as a result of mining m the upper catchment, but this is the first time that an attempt has been made to fingerprint the sources of suspended sediment. The idea of identifying sediment sources by fingerprinting was similar to that used by other authors, i.e. attempting to determine a distinctive chemical fingerprint for the different landuse, geology or subcatchments in the Tees. Field sediment samples were collected from potential source areas throughout the catchment and suspended sediment samples were collected from strategic points on the River Tees and its main tributaries. The samples were prepared using a sequential extraction procedure before analysis by ICP-AES. The samples were then subjected to several statistical procedures to determine which metals could classify the samples between the different source groups. Principal Components Analysis was the most successful tool for allowing interpretation of different sediment sources, identifying three possible sources for sedmient. These were the upstream bed and bank sediments, samples collected from the Leven catchment and the third source, which appeared to be the middle catchment agricultural areas. The data was subjected to a two-stage statistical analysis, as used by previous authors, but the data failed to provide a reliable fingerprint for use in a mixing model. Water samples collected along with suspended sediment showed distinct differences between the upper catchment and the lower tributaries, with samples from the lower Tees showing a degree of mixing. An attempt to use a mixing model failed, possibly owing to the small number of samples.
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Robson, Matthew Thomas. "Stream quality in a small urbanised catchment". Thesis, Sheffield Hallam University, 2004. http://shura.shu.ac.uk/20286/.
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River-length patterns in the chemistry and biology of the Charlton Brook, an unclassified watercourse in northwest Sheffield have been examined. Sampling sites for macroinvertebrates and pollutant analysis were used, in conjunction with Environment Agency General Quality Assessment (GQA) methodologies and hydraulic analysis of the catchment. Sites were strategically located to account for the tributaries and the brook downstream of their confluence, to assess the potential impact from surface water outfalls (SWOs).Variations in GQA parameters indicate a significant drop in quality downstream of the SWOs that discharge to the study watercourse, with a marked drop in biological diversity noted at the onset of urbanisation. The decline in biological quality however, is greater than that suggested by physico-chemical analysis alone. There was a significant inverse relationship between impermeable area and biological diversity. Analysis of polycyclic aromatic hydrocarbons (PAHs) and trace metals in sediment from the watercourse showed significant, yet irregular between site variations. PAHs in conjunction with metals as a function of the PEL-quotient method employed, suggest that all the sites sampled for macroinvertebrates have the potential for being adversely affected by the pollutants contained within the brook's sediment. Mean PEL-quotients suggest that sediment contamination within the brook is indicated at all sites. The potential toxicity of instream metal concentrations was determined using cumulative criterion unit (CCU) scores. CCU analysis highlighted cadmium, copper and lead as the major sources of potential instream toxicity with all sites exceeding the threshold for likely harm to aquatic life. In the absence of different physical characteristics, comparisons of the chemical and biological data indicate that the benthic macroinvertebrate population of such watercourses are adversely affected by the stormwater inputs.
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Ntakumba, Stanley Sixolile. "The hydrogeomorphology of the Featherstone Kloof Catchment". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1007862.
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Wetlands are an important part of the landscape as hydrogeomorphological ecosystems. Over the centuries their importance has not received relevant attention; instead they have been treated as wastelands impeding development for maximum economic benefits. Research evidence from different parts of the world has influenced the change of such negative perceptions to an extent that the issue of wetlands' rehabilitation/restoration, conservation and management is firmly on the global agenda and local agendas of various countries, as evidenced by the adoption of the Ramsar Convention in 1971, and the Working for Water and Working for Wetlands programmes of the South African government. The aim of this research was to investigate the hydrological and geomorphological functions of a headwater wetland located in the Featherstone Kloof Catchment near Grahamstown, South Africa. The research was based on the hypotheses that wetlands store sediments, attenuate floods, store water and prolong downstream flows. A literature survey was conducted to gauge the state of knowledge about wetlands, particularly their hydrogeomorphology. An attempt was made to locate the study area within the broad historical and spatial context using a number of methods, including the radiocarbon dating of wetland sediments, the review of relevant literature and the analysis of historical hydroclimatic data. The results revealed that the wetland has existed for approximately 2000 years - as the oldest radiocarbon date obtained was 1850±50 BP. An analysis of more than a century (+120 years) long Grahamstown rainfall series indicated a steady fluctuation of rainfall around the mean, with regular decada1 cycles of wet and dry spells. Years with more rain below average were more common than those with higher rainfall, and storms events were quite common in the III area over the period. The distribution of seasons in the area over a calendar year period was demonstrated through the use of evaporation data. An intensive monitoring of hydrological and geomorphological variables was carried out using a combination of methods. The topography of the instrumented site was determined using a Total Station from reference benchmarks. Hydrological measurements included a nest of forty-eight piezometers for water table monitoring, and streamflow gauges at the upstream and downstream limits of the study site. Soil stratigraphic analysis was carried out through field techniques and laboratory measurements. A survey of wetland sediments was carried out after the main floods events. Data generated were used to analyse relationships between various variables and their role on the functioning of the wetland. The water balance of the wetland was quantified. The results indicated that the wetland was able to perform the cited hydrogeomorphological functions to some extent. For example, one of the key findings of this research is that the wetland was important in sustaining base flows under normal circumstances. However, the wetland did little to attenuate large floods. The results also revealed some important questions that require further research, including the role played by extreme flood events in altering wetland characteristics, the contribution of each water balance component in the hydrological functioning of wetlands, and importance of quantifying sediment budgets of headwater wetlands. The study demonstrated the complex nature of the wetland hydro geomorphology and that certain questions about wetlands require direct field monitoring to be better understood.KMBT_363
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Namde, Noubassem Nanas 1955. "Simulation of micro catchment water harvesting systems". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/191121.
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A mathematical model for personal computers was prepared as a planning tool for development of micro catchment water harvesting systems. It computes runoff from natural or treated catchments, using estimated or actual parameters. The model also computes the water balance of the soil zone in the cultivated area and the water balance of the reservoir system which serves it. The model was calibrated with hydrolologic data and site characteristics for a location near Tucson, Arizona. Its prediction of cotton and grain sorghum yields was comparable to that of Morin (1977). An attempt was made to use weekly or monthly rainfall data for areas where daily data are unavailable. Lack of direct rainfall and runoff durations and infiltration characteristics made this attempt unsuccessful. This option cannot be used with the model in its current form.
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PERICO, ROBERTA. "GROUNDWATER-SURFACE WATER INTERACTION IN ALPINE CATCHMENT". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/374727.
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L'evidenza riconosciuta del riscaldamento globale richiede una valutazione del ciclo dell'acqua presente e futuro in Europa e nel mondo. Recentemente, è stata documentata l'evidenza di un regime idrologico modificato nelle Alpi sotto il cambiamento climatico. Tuttavia, secondo il quinto rapporto di valutazione dell'IPCC, è ancora necessario approfondire la nostra comprensione dell'impatto del cambiamento climatico e dell'uso del suolo sullo stoccaggio delle acque sotterranee nei bacini idrografici alpini. Una delle maggiori limitazioni all'analisi dell'interazione tra acque superficiali e sotterranee nei terreni alpini è la difficoltà di acquisizione dei dati e la limitata presenza di stazioni meteorologiche. Questi due fattori aumentano considerevolmente l'incertezza di una rappresentazione olistica dei processi idrologici e una stima affidabile della ricarica delle acque sotterranee. Lo scopo di questo lavoro di ricerca è quello di migliorare le attuali conoscenze sull'interazione tra le acque superficiali e gli acquiferi poco profondi e di definire un metodo per una modellazione integrata delle principali componenti del ciclo dell'acqua a scala di bacino da utilizzare come input per la modellazione delle acque sotterranee. La raccolta e l'uso di dati e metodi che permettono la massima discretizzazione dell'eterogeneità degli elementi coinvolti è il filo conduttore di questo lavoro. L'approccio scientifico è dimostrato per un caso di studio complesso, la valle della Valtellina (Italia settentrionale), per indagare l'interazione tra le componenti del ciclo idrogeologico e le loro proiezioni future secondo le dinamiche climatiche. Questa valle potrebbe essere considerata un perfetto caso di studio perché è caratterizzata da un sistema attivo che reagisce rapidamente alle variazioni meteorologiche e climatiche. Ciò è visibile dalla fluttuazione delle acque sotterranee e del fiume principale, l'Adda, durante eventi estremi di precipitazione e con lo scioglimento della neve durante i periodi di primavera/estate. La tesi è divisa in tre sezioni principali. La prima fornisce una descrizione dell'idrostratigrafia della pianura alluvionale della Valtellina. Questa sezione include il modello di flusso delle acque sotterranee in condizione stazionaria, sviluppato utilizzando FeFlow 7.2, e il relativo processo di calibrazione automatica della parametrizzazione idrogeologica. La seconda mostra la quantificazione del volume di stoccaggio stagionale delle acque sotterranee secondo il metodo del bilancio idrico residuo per due anni idrologici. Per la stima delle componenti principali (Precipitazione, Evapotraspirazione e Snow Water Equivalent), vengono testati nuovi promettenti database e metodi satellitari. L'ultimo capitolo descrive il modello di flusso transitorio delle acque sotterranee sviluppato con condizioni limite dinamiche ottenute dai metodi satellitari. Infine, il modello di flusso è stato utilizzato per valutare l'impatto sulle acque sotterranee di possibili scenari di cambiamento climatico.The recognized evidence of global warming demands assessment of the present and future water cycle in Europe and worldwide. Recently, evidence of modified hydrological regime in the Alps under climate change has been documented. However, according to the IPCC Fifth Assessment Report, it is still necessary to deepen our understanding of the impact of climate change and land use on groundwater storage in the alpine catchment areas. A major limitation to the analysis of the surface water-groundwater interaction in alpine terrain are the difficultly of data acquisition as well as the limited presence of meteorological stations. These two factors considerably increase the uncertainty of a holistic representation of the hydrological processes and a reliable estimation of groundwater recharge. The aim of this research work is to improve the current knowledge on the interaction between surface water and shallow aquifers and to define a method for an integrated modelling of the main components of the water cycle at the catchment scale to be used as input for groundwater modelling. The collection and use of data and methods that allow for the maximum discretisation of the heterogeneity of the elements involved is the guiding thread of this work. The scientific approach is demonstrated for a complex case study, the Valtellina valley (northern Italy), to investigate the interaction among the components of hydrogeologic cycle and their future projections according to climate dynamics. This valley could be considered a perfect case study because it is characterized by an active system that rapidly reacts to meteorological and climatic variations. This is visible by the fluctuation of the groundwater and of the main river, Adda River, during extreme precipitation events and with snow melts during the spring/summer periods. The thesis is divided into three main sections. The first provides a description of hydro-stratigraphy of the Valtellina valley floodplain. This section includes the groundwater flow model in a steady state condition, developed by using FeFlow 7.2, and the relative automatic calibration process for the hydrogeologic parametrization. 5 The second shows the quantification of seasonal groundwater storage volume according to the residual water budget method for two hydrologic years. For the estimation of the main components (Precipitation, Evapotranspiration and Snow water equivalent), new promising satellite-based database and methods are tested. The last one describes the tranFinally, the flow model has been used to evaluate the impact on groundwater of possible climate change scenarios.sient groundwater flow model developed with dynamic boundary conditions obtained from satellite-based methods.
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Sabetraftar, Karim y Karim Sabetraftar@anu edu au. "The hydrological flux of organic carbon at the catchment scale: a case study in the Cotter River catchment, Australia". The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20070502.141450.
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Existing terrestrial carbon accounting models have mainly investigated atmosphere-vegetationsoil
stocks and fluxes but have largely ignored the hydrological flux of organic carbon. It is
generally assumed that biomass and soil carbon are the only relevant pools in a landscape
ecosystem. However, recent findings have suggested that significant amounts of organic carbon
can dissolve (dissolved organic carbon or DOC) or particulate (particulate organic carbon or
POC) in water and enter the hydrological flux at the catchment scale. A significant quantity of
total organic carbon (TOC) sequestered through photosynthesis may be exported from the
landscape through the hydrological flux and stored in downstream stocks.¶
This thesis presents a catchment-scale case study investigation into the export of organic carbon
through a river system in comparison with carbon that is produced by vegetation through
photosynthesis. The Cotter River Catchment was selected as the case study. It is a forested
catchment that experienced a major wildfire event in January 2003. The approach is based on an
integration of a number of models. The main input data were time series of in-stream carbon
measurements and remotely sensed vegetation greenness. The application of models to
investigate diffuse chemical substances has dramatically increased in the past few years because
of the significant role of hydrology in controlling ecosystem exchange. The research firstly
discusses the use of a hydrological simulation model (IHACRES) to analyse organic carbon
samples from stream and tributaries in the Cotter River Catchment case study. The IHACRES
rainfall-runoff model and a regionalization method are used to estimate stream-flow for the 75
sub-catchments. The simulated streamflow data were used to calculate organic carbon loads
from concentrations sampled at five locations in the catchment.¶
The gross primary productivity (GPP) of the vegetation cover in the catchment was estimated
using a radiation use efficiency (RUE) model driven by MODIS TERRA data on vegetation
greenness and modeled surface irradiance (RS). The relationship between total organic carbon
discharged in-stream and total carbon uptake by plants was assessed using a cross-correlation
analysis.¶
The IHACRES rainfall-runoff model was successfully calibrated at three gauged sites and
performed well. The results of the calibration procedure were used in the regionalization method
that enabled streamflow to be estimated at ungauged locations including the seven sampling
sites and the 75 sub-catchment areas. The IHACRES modelling approach was found appropriate
for investigating a wide range of issues related to the hydrological export of organic carbon at
the catchment scale. A weekly sampling program was implemented to provide estimates of
TOC, DOC and POC concentrations in the Cotter River Catchment between July 2003 and June
2004. The organic carbon load was estimated using an averaging method.¶
The rate of photosynthesis by vegetation (GPP) was successfully estimated using the radiation
use efficiency model to discern general patterns of vegetation productivity at sub-catchment
scales. This analysis required detailed spatial resolution of the GPP across the entire catchment
area (comprising 75 sub-catchment areas) in addition to the sampling locations. Important
factors that varied at the catchment scale during the sampling period July 2003 June 2004,
particularly the wildfire impacts, were also considered in this assessment.
¶
The results of the hydrologic modelling approach and terrestrial GPP outcome were compared
using cross correlation and regression analysis. This comparison revealed the likely proportion
of catchment GPP that contributes to in-stream hydrological flux of organic carbon. TOC Load
was 0.45% of GPP and 22.5 - 25% of litter layer. As a result of this investigation and giving due
consideration to the uncertainties in the approach, it can be concluded that the hydrological flux
of organic carbon in a forested catchment is a function of gross primary productivity.
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Shadeed, Sameer. "Up to date hydrological modeling in arid and semi-arid catchment, the case of Faria catchment, West Bank, Palestine". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-54205.
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Sabetraftar, Karim. "The hydrological flux of organic carbon at the catchment scale : a case study in the Cotter River Catchment, Australia /". View thesis entry in Australian Digital Theses Program, 2005. http://thesis.anu.edu.au/public/adt-ANU20070502.141450/index.html.
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Broxton, Patrick. "UNDERSTANDING THE IMPORTANCE OF ASPECT ON MOUNTAIN CATCHMENT HYDROLOGY: A CASE STUDY IN THE VALLES CALDERA, NM". Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/193452.
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In surface hydrology, much attention is paid to the effects of changing water fluxes, however there is less of a focus on the effects of changing energy fluxes. These energy fluxes are an important driver of many hydrological processes such as evapotranspiration and snow sublimation/ablation. The hypothesis that varying energy fluxes are important to the hydrological features of a catchment is tested by an experiment that involves calculating mean transit times for a number of catchments that drain different aspects of a large dome located in the Valles Caldera, New Mexico, called Redondo Peak. These catchments have different orientations and therefore receive different amounts of solar radiation. There is a general correlation between mean transit times, as determined by lumped-parameter convolution, and aspect, suggesting that in the Valles Caldera, transit times might be affected by a variety of features that are influenced by exposure to solar radiation, such as slope steepness, vegetation patterns, and soil depth. To put these transit times into context, I also used a distributed physically-based model to simulate a number of factors simultaneously to determine how hydrological features are influenced by aspect. This modeling excercise has illuminated the aspect-dependence of hydrological features such as the timing and intensity of snowmelt and soil moisture patterns, and it has quantified differences in energy and water fluxes on different aspects. These factors affect both water storage and water fluxes, and are therefore tied to transit times.
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Laceby, John Patrick. "The Provenance of Sediment in Three Rural Catchments in South East Queensland, Australia". Thesis, Griffith University, 2012. http://hdl.handle.net/10072/367963.
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Moreton Bay, in South East Queensland, Australia, is a Ramsar wetland of international
significance. A decline of the bay’s ecosystem health has been primarily attributed to
sediments and nutrients from catchment sources. The Healthy Country (HC) project, a
Queensland Government funded ‘proof of concept’ initiative, is dedicated to reducing rural
diffuse sediments and nutrients entering waterways and ultimately Moreton Bay. Three
focal catchments, Blackfellow Creek, Knapp Creek and the Upper Bremer River, were
selected to trial rehabilitation techniques for the region. Sediment budgets for these focal
catchments, developed using catchment scale modelling (SedNet), indicated gully erosion
dominates the supply of sediment in Knapp Creek (90%) and the Upper Bremer River
(80%) whereas erosion from cultivated soils is the primary sediment source in Blackfellow
Creek (40%). These sediment budgets, that include predictions of both the spatial sources
of sediment and the primary erosion processes, form a series of hypotheses in each focal
catchment that are tested in this thesis.
Fallout-radionuclide activity concentrations (137Cs and 210Pbex) of in-stream sediment
sampled in each focal catchment were used in conjunction with regional source data to
test hypotheses pertaining to dominant erosion processes, specifically the relative
sediment contributions from surface and subsoil (gully and channel bank) sources.
Distribution modelling results indicated subsoil erosion processes dominate the supply of
sediment in both Knapp Creek (100%) and the Upper Bremer River (100%). In Blackfellow
Creek, the similarity of cultivated (surface) and subsoil source fallout-radionuclide activity
concentrations resulted in no discrimination between these sources that were modelled in
combination to contribute >90% of sediments. Importantly there was no discrimination
between gully and channel bank erosion sources in Knapp Creek and the Upper Bremer
River.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Rodger, Jessica Ruth. "Intraspecific genetic, morphological and life history structuring of brown trout (Salmo trutta) in a single complex catchment, the Foyle catchment". Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8522/.
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Intraspecific genetic, morphological and life history structuring is evident in many taxa. Where such intraspecific structuring exists, study of the nature of the patterns displayed can reveal much about the evolutionary processes that operate during the early stages of divergence. Intraspecific structuring is particularly prevalent amongst fishes that occupy recently glaciated freshwater systems. One such species, the brown trout, Salmo trutta, was the subject of the work presented in this thesis. Genetic and morphological intraspecific structuring of brown trout was examined across a single but large dendritic catchment, the River Foyle, Ireland. Structuring was examined at three spatial scales (large-scale, compared between major sub-catchments; medium-scale, compared between tributaries within sub-catchments; small-scale, compared between streams within tributaries). The two general aims of the study were to look for any structuring in either phenotype or genotype in brown trout across the catchment and, if this was found, to look for landscape or environmental gradients that might be driving such structuring. Using a suite of 21 microsatellite markers that were chose for their ability to resolve population differences in this species elsewhere, this study identified clear and distinct genetic structuring. Brown trout collected from 28 sampling sites, resolved into 21 genetically distinct and discrete populations using a hierarchical approach implemented in STRUCTURE. The structuring was evidence across all three spatial scales. There was strong evidence of isolation by distance and isolation by environment playing a role in shaping the magnitude of the genetic differences between populations. Landscape variables which are shaped by anthropogenic impacts (urbanised area (measured as the number of houses in the catchment), proximity to farmland (measured as the distance to the nearest farm) and concentration of phosphorus in the water) showed the greatest effects in shaping the genetic population structuring (chapter 2). In a parallel study, the morphological structuring of brown trout from across the Foyle catchment was investigated at three spatial scales. Morphology was measured as the shape of brown trout determined by Geometric Morphometric Analysis of fixed position landmarks identified on photographs of trout taken from 22 sampling sites across the catchment. Very clear, statistically significant differences in morphology (fish shape) were evident for all the 21 sampling sites (one sampling site was removed from the analysis due to small sample size) with Canonical Variate Analysis resolving 21 discrete phenotypic groups. Morphological structuring was evident across all spatial scales (large, medium and small). Analysis showed that genetic distance and geographic distance between morphological groups was significantly correlated with morphology of populations, with morphological groups that were most divergent from each other also being most genetically distinct and geographically more distant. The effect of landscape and environmental variables driving morphology of populations was tested. In-stream substrate composition, water pH, stream order, site elevation, river gradient and the number of houses per km2 (representative of urban area) were all found to have a significant effect on morphology of populations. However, once the effect on morphology on these environmental variables were accounted for the residual effect of genetic distance was not significant (chapter 3). To attempt to discriminate between three alternative population genetic hypotheses for the origin of two alternative life history strategies in brown trout; freshwater residency and anadromy, the genetic structuring of brown trout was examined between life history strategy (anadromy or resident), between three sites and across two years (2013/2014) for brown trout collected from the Foyle catchment. There was no evidence of population structuring being attributed to life history strategy (that is no genetic differences between anadromous or resident trout). There was however strong and clear evidence of five genetic populations based on geographical site. Two sympatric populations were identified at each of two locations. However, both populations in each river were composed of both freshwater resident and anadromous brown trout, although the frequency of each life history strategy significantly differed between these rivers. The results of this study support the concept that partial migration in brown trout is most likely driven by a quantitative threshold trait, where the threshold trait value varies both between populations and between individuals within populations (chapter 4). It is critical, for effective management of the relatively high economic value anadromous component of brown trout populations in a catchment, to be able to identify which tributaries are contributing most to their production. A Genetic Stock Identification (GSI) analytical framework was used to determine the tributary of origin for anadromous brown trout captured from a mixed stock within the River Faughan sub-catchment, River Foyle and to look for any evidence of straying. The results showed that three genetic populations from specific parts of the sub-catchment contributed disproportionately to the production of anadromous brown trout. There was also evidence of straying of anadromous trout, particularly to one tributary elsewhere in the catchment (chapter 5). Taken together this body of work has demonstrated strong genetic and morphological structuring amongst brown trout in this large dendritic catchment. Genetic structuring seems to be at its most extreme when driven by factors which could be regarded as anthropogenic. This raises questions about human effects on the process of genetic divergence. Morphological structuring was, if anything even stronger than genetic structuring. Although there was evidence of genetic divergence between populations of differing morphologies, this neutral genetic differentiation was not a significant driver of morphological variation once landscape and environmental variables, such as substrate composition, driving morphological differences were taken into account. This suggests that the environmental drivers of structuring are greater in magnitude than neutral genetic divergence. Examining genetic structuring between two common morphologies of brown trout (anadromous and freshwater resident) in more detail, revealed no genetic differentiation between life history strategies but there was evidence of differences in frequency of life history between populations. Using the genetic structuring of brown trout as a genetic baseline it was possible to determine which tributaries within the River Faughan sub-catchment produce anadromous brown trout. If some discrete populations in a catchment are contributing disproportionately to the anadromous trout population (as they are in the Foyle) there is a strong risk of over exploitation and a need for enhanced attention in the nursery areas for those populations. These results have significant implications for the management of all trout in the Foyle catchment and elsewhere.
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Mandlazi, Nompumelelo Pretty. "Hydrological Characterisation of Wetlands: Understanding wetlands-catchment linkages". University of the Western Cape, 2017. http://hdl.handle.net/11394/5877.
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Magister Scientiae - MSc (Earth Science)This study explores the hydrological processes of selected wetlands in four different catchments in South Africa (the Nuwejaars River in the Western Cape which has the Elandsdrift-Wiesdrift wetland; the Mohlapetsi river in the lower Olifants river in Limpopo where the GaMampa wetland is located; the Usuthu River in Mpumalanga which has the Bonnie Brook wetlands; and the UMgeni River in KwaZulu Natal with the Lions river wetlands). The representation of wetlands processes in the Pitman and Agricultural Catchments Research Unit (ACRU) - commonly used hydrological models in Southern Africa - is also evaluated. In the Nuwejaars river catchment, hydrological processes were monitored for over a year, while literature and available conceptual frameworks were used in the other catchments. The Pitman and ACRU models were used to represent the main process and to determine how wetlands influence catchment-scale processes. Current understanding of the hydrology of Elandsdrift-Wiesdrift floodplain suggests that the floodplain is dominated by precipitation, overland flow from the catchment area of the floodplain, evapotranspiration, and surface flow from the left sides of the floodplain to the Nuwejaars River. In the Mohlapetsi River catchment the GaMampa wetland is dominated by local rainfall falling directly onto the wetland, surface runoff from the valley sides, and spring flow at the bottom of the surrounding hills occasioned by recharge on the hills, evapotranspiration and lateral flow between the wetland to the river. The Bonnie Brook and Lion's river catchment are valley bottom floodplains dominated by evapotranspiration, precipitation, overland flow, overbank flooding, groundwater discharge and groundwater recharge. Hydrological modelling of wetlands in the four basins yielded reasonable success (Nash Sutcliffe (NSE) ranged from 0.510 to 0.75 with less than 15% percentage of different between observed and selected mean values (PBIAS). Most characteristics of the observed flows for the four catchments were satisfactorily simulated. The overall results from both models indicate that the models can reasonably represent hydrological processes of wetlands, though there is need to improve the routines in both models. Therefore, further studies that will focus on parameter estimation and improving the current wetland modules of both models are recommended.
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Newham, Lachlan Thomas Hopkins y lachlan newham@anu edu au. "Catchment Scale Modelling of Water Quality and Quantity". The Australian National University. Centre for Resource and Environmental Studies, 2002. http://thesis.anu.edu.au./public/adt-ANU20050919.144548.
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Appropriately constructed pollutant export models can help set management priorities for catchments, identify critical pollutant source areas, and are important tools for developing and evaluating economically viable ways of minimising surface water pollution.¶
This thesis presents a comparison, an evaluation and an integration of models for predicting the export of environmental pollutants, in particular sediment, through river systems. A review of the capabilities and limitations of current water quality modelling approaches is made. Several water quality and quantity modelling approaches are applied and evaluated in the catchment of the upper Murrumbidgee River.¶
The IHACRES rainfall-runoff model and a simple hydrologic routing model are applied with the aim of developing a capacity to predict streamflow at various catchment scales and to enable integration with other pollutant load estimation techniques. Methods for calculating pollutant loads from observed pollutant concentration and modelled streamflow data are also investigated. Sediment export is estimated using these methods over a 10-year period for two case study subcatchments. Approaches for water quality sampling are discussed and a novel monitoring program using rising stage siphon samplers is presented.
Results from a refinement of the Sediment River Network model in the upper Murrumbidgee catchment (SedNet-UM) are presented. The model provides a capacity to quantify sediment source, transport and to simulate the effects of management change in the catchment. The investigation of the model includes rigorous examination of the behaviour of the model through sensitivity assessment and comparison with other sediment modelling studies. The major conclusion reached through sensitivity assessment was that the outputs of the model are most sensitive to perturbation of the hydrologic parameters of the model.¶
The SedNet-UM application demonstrates that it is possible to construct stream pollutant models that assist in prioritising management across catchment scales. It can be concluded that SedNet and similar variants have much potential to address common resource management issues requiring the identification of the source, propagation and fate of environmental pollutants. In addition, incorporating the strengths of a conceptual rainfall-runoff model and the semi-distributed SedNet model has been identified as very useful for the future prediction of environmental pollutant export.
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Schlapp, Julia Emily y julia schlapp@rmit edu au. "Modelling Fertiliser Use in the Glenelg Hopkins Catchment". RMIT University. Mathematics and Geospatial Science, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090602.144534.
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The improvement of water quality in the streams of the Glenelg Hopkins catchment is a priority of the Glenelg Hopkins regional strategy. A major source of water pollution in the region is linked to agricultural activities as high nutrient levels from runoff have the potential to increase the incidence of blue-green algae in the waterways. Land use change, reduced rainfall, more frequent extreme rainfall events and higher temperatures associated with climate change are likely to exacerbate this trend. Water testing data of the Total Phosphorus (TP) levels in the Hopkins River and at other sites within the Hopkins Catchment indicate increasing incidence of TP above the Environment Protection Authority's target levels for extended periods of each year. Earlier research indicated that phosphorus in runoff increases when pasture fertility increases and that fertiliser management practices should be considered as an element of preventative action for reducing nutrient pollution. During our research, a survey was undertaken in the Hopkins River catchment, to determine the current management of phosphorus (P) fertilisers on grazing and mixed enterprise farms, the attitude of farmers to natural resource management and their understanding of nutrient pollution. The survey also gathered information on the way farmers made fertiliser management decisions. If cooperation relating to phosphorus fertiliser application could be facilitated between groups of farmers, it may be possible to reduce nutrient runoff into the Hopkins waterways. Cooperative game theory has successfully been used worldwide in the resolution of environmental problems where there is an economic impact to the decision making process. In this project, the amount of phosphorus applied per hectare was used in a cooperative game theory model assessing the potential for cooperative action on phosphorus management by groups of farmers, based on the trade off between the economic cost of pollution to the region waterways and the economic production benefits to the individual. The outcome of this work was individual optimal strategies for fertiliser application, allowing individual farmers to reduce their impact of agricultural production on the health of the catchment. Involving the farmer groups, while undertaking the project, raised awareness amongst the farming population of the regional nutrient pollution caused by runoff from agricultural land, and enlisted their assistance towards adopting a cooperative approach to the problem. In addition, the results have been mapped using a Geographical Information System (GIS) for visual presentation and to demonstrate the use of this process in natural resource management with the farmer groups.
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Riveros-Iregui, Diego Andres. "Hydrologic-carbon cycle linkages in a subalpine catchment". Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/riveros-iregui/Riveros-IreguiD1208.pdf.
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The feedbacks between the water and the carbon cycles are of critical importance to global carbon balances. Forests and forest soils in northern latitudes are important carbon pools because of their potential as sinks for atmospheric carbon. However there are significant unknowns related to the effects of hydrologic variability, mountainous terrain, and landscape heterogeneity in controlling soil carbon dioxide (CO 2) efflux. Mountainous terrain imposes large spatial heterogeneity in the biophysical controls of soil CO 2 production and efflux, including soil temperature, soil water content, vegetation, substrate, and soil physical properties. Strong spatial and temporal variability in biophysical controls can lead to large heterogeneity in the magnitude of soil CO 2 efflux. This dissertation research investigates the relationships between these biophysical controls and the resultant CO 2 efflux across the soil-atmosphere interface in a 393-ha subalpine catchment of the Northern Rocky Mountains. This study incorporates knowledge gained through field observations (2 growing seasons) at multiple locations distributed across the watershed, and a range of empirical analytical techniques including a modeling approach to estimate point to catchment scale soil CO 2 efflux. Variability in soil CO 2 efflux was strongly related to topography and landscape structure. Riparian meadows were found to have the highest rates of cumulative soil CO 2 efflux across the entire watershed, likely due to more accumulation of soil water than upland sites, leading to enhanced plant and microbial respiration in riparian meadows. Landscape context and appreciation of organized heterogeneity are critical to estimation and interpretation of watershed-scale rates of soil CO 2 efflux and for up-scaling plot or point measurements of soil CO 2 efflux to larger spatial scales. This dissertation provides examples and suggestions for corroboration and integration of soil and canopy level CO 2 fluxes and for process understanding of spatiotemporal variability of biogeochemical processes driven by the hydrologic cycle.
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Hill, P. I. "Extreme flood estimation for the Onkaparinga River Catchment /". Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09ENS/o9ensh647.pdf.
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Tsegaw, Aynalem Tassachew. "Short term Distributed Hydrological Modelling of Gaula Catchment". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12597.
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Testing and trying out of the applicability and utility of watershed hydrological models in different; catchment sizes, hydro-geologic conditions, soil conditions and with different time resolutions is necessary for a range of spatial scales to assess the utility of these models in water shade management means like flood protection, land slide prevention, erosion control etc. The main purpose of this thesis is to tryout TOPLAND hydrological model, i.e. the new developments to the LANDPINE model allowing for using TOPMODEL distributed runoff generation, with different precipitation input methods. It focuses on the simulation of precipitation events with time resolution of one hour. Short term time resolution event simulations are important to capture flow events in small and large catchments; since these events are responsible for local flood, land slide etc., especially in areas where they are strongly localized. The model simulation has been carried out using three different precipitation input methods; gauge IDW interpolation, gauge simulated and radar based precipitation data for the selected hourly events of 2006 (27-07-2006 00:00 to 29-07-2006 23:00) and 2009 (19-07-2009 05:00 to 25-07-2009 20:00). 2009 Event The 2009 event is characterized by high peak and uniformly distributed event. For the bias corrected radar precipitation, the objective method of result comparison showed an excellent correspondence between observed and simulated flows with NS (R2) of 0.98, correlation (R2) of 0.98 and PBIAS of 0.48% at the calibration point (Gaulfoss). The bias corrected radar precipitation also showed a very good performance of the model at the interior uncalibrated gauging stations with average values of NS (R2) 0.85, correlation (R2) 0.93 and PBIAS 16.6% of the HugdalBru, Lillebudal and Eggafoss gauging stations. The gauge IDW interpolation and gauge simulated precipitation input methods also showed a very good performance of the model both at the calibration and internal uncalibrated gauging stations. 2006 Event The 2006 event is characterized by low peak and unevenly distributed (localized) event. The bias corrected radar precipitation is the only precipitation input method that made possible for calibration of the model. The objective method of result comparison showed a very good result for NS (R2) of 0.96, correlation (R2) of 0.97 and PBIAS of 5.1% at the calibration point (Gaulfoss). At the internal uncalibrated gauging stations, the correlation and PBIAS showed a good performance with average correlation (R2) of 0.77 and PBIAS of 21.3% and a poor average NS (R2) of 0.3.
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Wicks, Jonathan Mark. "Physically-based mathematical modelling of catchment sediment yield". Thesis, University of Newcastle Upon Tyne, 1988. http://hdl.handle.net/10443/152.
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A physically-based, distributed sediment yield component has been developed for the SHE hydrological modelling system. This new component models the hillslope processes of soil detachment by raindrop impact, leaf drip impact and overland flow, and transport by overland flow. If the eroded soil reaches a river system it is routed downstream along with any inobilised river bed material. Deposition on land or in a river is simulated and the river bed material size distribution is continuously updated with allowance for armour layer development. The equation developed for soil detachment by raindrop and leaf drip impact was successfully tested using data from a field plot with a range of soybean canopy covers and rainfall intensities. The soil detachment coefficient in this equation was determined for a range of soil types and showed a variation consistent with that which may be expected from a consideration of the physics of a soils resistance to detachment. At present two soil detachment coefficients need calibration. In order to investigate the variation in these coefficient values, as well as to test the component, various applications were carried out. The hilislope sub-component was applied to rainfall simulator plots with a variety of surface conditions. Two sets of calibration parameters, distinguishable on a physical basis according to the degree of soil disturbance, were found to be appropriate for all the plots. To investigate scale effects, parameters calibrated at the rainfall simulator plot scale were transferred to a 1-ha rangeland sub-catchment. With no further calibration, the catchmerit response for four events was poorly simulated for both water and sediment. However, with reasonable variations in the antecedent soil moisture content but no variation in plot calibrated sediment parameters, the sediment yield for two of the four events could be successfully simulated. These applications suggest that parameter transfer is feasible if the sediment yield characteristics at the different scales are similar. Further applications of the hilislope sub-component were carried out for two small agricultural catchments. The sediment response could be simulated to at least the same accuracy as achieved by two existing distributed soil erosion models. The channel sub-component was applied to the East Fork River, Wyoming. Although the complex sediment storage/supply effects could not be reproduced completely, the simulated response was nevertheless of similar accuracy to that achieved by two existing alluvial river models. The new component is considered to be a valuable contribution to sediment yield modelling as a physically-based approach is used for both the hilislope and channel phases of the catchinent sediment system, within the framework of an advanced hydrological modelling system.
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Hyde, Michael L. "Urban runoff quality in the River Sowe catchment". Thesis, Coventry University, 2006. http://curve.coventry.ac.uk/open/items/9c34fa51-7611-4362-844d-30d87ba84205/1.
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There have been no previous studies carried out on the impact of urban runoff in the Coventry City centre area. The culverted nature of the River Sherbourne, and many of its tributaries, makes the investigation of intermittent pollution and rainfall events expensive and impractical, when using traditional spot sample methods. Storm events have been monitored over a period of over 60 months upstream and downstream of the City, using continuous water quality monitors and auto-spot sample methods. The receiving waters of the River Avon had previously suffered annual fish mortalities as a result of summer storm events causing oxygen depletion. Previous studies (Clifforde and Williams 1997) on the impact of Coventry Sewage Treatment Works effluent on the watercourse, have suggested a major component of the intermittent pollutant load arising from the City (upstream of the Sewage Treatment Works), which requires evaluation and remediation. This research identifies the contaminants found during a series of storm events impacting on the River Sherbourne culvert, and discusses the relationship between them and the increased flow measured. The methodology was divided into 3 Phases; Phase 1 examined all of the watercourses in the River Sowe catchment, and identified the culverted streams and drainage system giving an indication of the presence of pollutant sources. Continuous monitors were deployed within the four identified drainage systems to pinpoint intermittent and illegal contaminated discharges, and these discharges were subsequently redirected to the foul sewer or stopped. Phase 2 examined the quality of the River Sherbourne culvert upstream and downstream of the city centre, and demonstrated (using continuous monitors and automated sampling), that six combined sewer overflows discharging to the watercourse upstream of the culvert were opening unsatisfactorily. The dissolved oxygen levels were significantly reduced during rainfall events (with a loss of diurnal variation), and total ammonium levels exceeded current water quality standards. The results were used to instigate a remediation scheme to replace the overflows with additional foul sewage capacity, and a single high-level storm relief. Phase 3 examined the impact of urban runoff during rainfall events after the improvements made following Phases 1 and 2. The results suggest a marked improvement in the water quality, with little impact from organic pollutants. Dissolved oxygen concentrations remained high during many of the post-remedial rainfall events, and ammonia levels remained largely insignificant. The results indicated a fall in pH levels during the rainfall events and increases in all of the heavy metals analysed, though not beyond current water quality guidelines. The efficiency of using continuous monitoring in Coventry was assessed and likely sources of the contaminants in urban runoff were considered. The statistics of compliance with percentile standards do not allow for short-term pollution or storm events, which may kill all aquatic life whilst not breaching water quality standards. Using continuous monitors to identify intermittent and illegal discharges in underground drainage systems was an efficient and cost-effective method of reducing the impact of urban runoff in a failing watercourse. The methodology can be applied to other urban areas to identify unidentified illegal and intermittent point sources. Routine monthly monitoring of an urban watercourse may not identify the peaks and troughs associated with rainfall events that may breach toxicological guidelines, and will not identify intermittent and unknown pollutant sources; particularly when discharging outside of normal working hours. This research was a unique and comprehensive investigation into the nature and composition of urban runoff in the City of Coventry, and local data gathered will be invaluable in promoting further research, improving local knowledge of the urban environment in preparation for the Water Framework Directive (2000/60/EC), and in planning for environmental improvements in the future.
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Birkinshaw, Stephen J. "Nitrate transport component for SHETRAN catchment modelling system". Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336759.
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Coulthard, Thomas James. "Modelling upland catchment response to Holocene environmental change". Thesis, University of Leeds, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364900.
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Wood, K. A. "Swan-plant interactions in a chalk river catchment". Thesis, Bournemouth University, 2012. http://eprints.bournemouth.ac.uk/20761/.
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Plants are of fundamental importance to the structure, functioning and service provision of many ecosystems. However, herbivores can have negative ecological and socioeconomic effects on plant communities through consumption, trampling and alteration of nutrient cycles. In this thesis I address a particular herbivore-plant interaction: the grazing of plants in chalk river catchments, principally the submerged macrophyte water crowfoot (Ranunculus penicillatus ssp. pseudofluitans (Syne) S.D. Webster) and terrestrial pasture grass species, by flocks of non-breeding mute swans (Cygnus olor Gmelin, 1789). This research was carried out over two years in the River Frome catchment (Dorset, UK). Based on a meta-analysis of previous waterfowl grazing studies I show that waterfowl biomass density (kg ha-1) rather than individual density (ind. ha-1) is a better predictor of reductions in plant standing crop. Most studies to date have analysed such reductions using only individual densities, despite large between-taxa variation in waterfowl body mass, diet and intake rates. I quantified the abundance, species richness, evenness, flowering and dominance of the chalk river aquatic plant community in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the growth cycle. The relative importance of herbivory, riparian shading, water temperature and distance downstream varied between different phases of the plant growth cycle, highlighting the importance of seasonal patterns in regulation of plant community structure. The River Frome swan population varied seasonally, being highest in the winter. The population was dominated by non-breeding adults and juveniles that lived in flocks. These flocks exhibited strong seasonal habitat switches between terrestrial pasture in winter and spring, and river in summer and autumn. I provided evidence that this switch was linked to the seasonal decrease in water velocity between spring and summer, which reduced the metabolic costs of river feeding and increased the relative profitability of aquatic food resources. I used a mathematical population model and an individual-based behavioural model respectively to explore two management options for the alleviation of the swan grazing conflict in chalk rivers: population control and habitat alterations. Population control measures, such as clutch manipulations, fertility control, culling or translocations, were predicted to be unsuccessful except at impractically high levels of management effort, due to the effects of immigration and high survival rates in offsetting removed eggs or individuals. Habitat alterations, in particular the narrowing of river channels to cause a local increase in water velocity and thus swan foraging costs, are more promising management options as they require lower management effort, are less ethically controversial, and address the fundamental reason why swans select their food resources, the rate of net energy gain (‘profitability’).
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Howes, S. "A mathematical hydrological model for the ungauged catchment". Thesis, University of Bristol, 1985. http://hdl.handle.net/1983/1affdf54-f3d2-4dbe-83b0-836695ef0c8e.
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In geographical hydrology the~e has been more interest in scientific rather than in practical application of mathematical models of catchment hydrology. This thesis emphasizes the importance of examining the potential of developments in scientific research programmes for practical hydrological applications, and in particular provides discussion upon the following five issues: 1 The application of hydrological models to ungauged catchments where no historical streamflow record is available for calibration. 2 The potential of hydrological models for routine and operational application. This application limits the data and computer resources which are available for use. 3 The development and application of a thorough model evaluation strategy which examines the suitability of a model in the context of a specific application requirement. 4 The selection of a conceptually sound model structure. S The development and evaluation of a suitable methodology for the incorporation of the spatial variability of catchments into hydrological" models. To provide a basis for the discussion of these five issues, this thesis provides the details of the modification of a currently used hydrological model, RYMO. The modification of this model involves the replacement of the empirical curve number model for runoff derivation with a physically based parameter infiltration model. A number of comparisons of HYMO and the modified version, HYM02, indicates that conceptual, parameter estimation, prediction, and sensitivity improvements have indeed been secured by the development of the modified model.
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Dondo, C. "Bayesian networks for spatio-temporal integrated catchment assessment". Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/10327.
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Includes abstract.Includes bibliographical references (leaves 181-203).
In this thesis, a methodology for integrated catchment water resources assessment using Bayesian Networks was developed. A custom made software application that combines Bayesian Networks with GIS was used to facilitate data pre-processing and spatial modelling. Dynamic Bayesian Networks were implemented in the software for time-series modelling.
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Yu, Mengran. "Approaches for investigating wildfire impacts on catchment hydrology". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20565.
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Wildfire has serious impacts on the hydrological cycle and water quality of forested catchments. Forested catchments are commonly used as an important source of drinking water supply in Australia and internationally. Monitoring short-term and long-term post-wildfire catchment hydrology (water quantity and quality) change is important for catchment management. Past studies are limited by data availability and method used. In this thesis, we firstly used empirical (linear mixed model and k-mean clustering) and physical-based hydrological model – Soil and Water Assessment Tool (SWAT) to detect the effect of wildfire on forested catchment hydrology and then built scenarios using physical-based model to investigate the cause of the catchment hydrology change and identify the wildfire sensitive areas in catchments for catchment protection. The case study used here is the 2001/2002 Sydney wildfire, 10 years of pre-wildfire and 10 years of post-wildfire water quantity and quality data were collected by WaterNSW and used in this study. We have successfully used linear mixed model and SWAT to detect the wildfire effect on catchment hydrology in the thesis. As a result, the empirical model observed a long-term (5 - 10 years) post-wildfire water quality change; this change is more considerable during post-wildfire event period. The result from physical-based hydrological models also indicated a long-term change in total suspended sediments concentration during post-wildfire period. In addition to the change detected. Our scenario in physical-based models also observed that post-wildfire soil carbon change has limited effect on catchment hydrology and vegetation change is the main cause of post-wildfire catchment hydrological change. Out models also suggested that sub-catchments with higher slope increases, shorter slope, and smaller soil top layer bulk density, clay, and carbon content, are the most wildfire sensitive areas and should be protected the most.
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Lee, Lisa Yu-Ting. "EFFICIENT WATER ALLOCATION IN A HETEROGENEOUS CATCHMENT SETTING". Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/2466.
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The problem of water scarcity has become one of the most controversial topics in Australia over the past decades, with particular focus being the ‘sustainable’ allocation of water between extractive and environmental purposes. Geographical factors are defining the extreme variability in climate and water supply in Australia and, in the past, this was used as a rationale for the construction of large irrigation projects to deliver water to rural, urban, and industrial users. During this ‘expansionary’ phase of Australia’s water use sector, the cost of augmenting supply was relatively low and environmental considerations were secondary to the development imperative. As a result, water resources became over-allocated for extractive uses spurred on by consistent underpricing of water, which indicated a failure to reflect the true cost of water supply. As Australia’s water economy entered a ‘mature’ phase, it was no longer possible to increase supply cheaply as the most easily accessible water resources had already been captured. This was followed by widespread environmental degradation manifested in the Murray- Darling Basin, the nation’s largest river basin which hosts much of Australia’s agricultural production. Consequently, the focus shifted towards demand management, leading to a myriad of regulation aimed at increasing the allocative efficiency of scarce water resources. Towards this end, substantial government funding was injected into the various initiatives throughout the water reform process. Despite the on-going government activities in the area of water reform, the understanding of the actual economic impact and environmental outcomes of various water policies in practice remains limited. In the absence of such understanding, the effectiveness of various government water initiatives is ambiguous and inevitably compromised. The present study addresses this knowledge gap by establishing a method for evaluating the economic and environmental outcomes of environmentally-oriented polices that affect irrigated industries in a catchment. The method is based on an integrated biophysical and economic modelling approach, which enables spatial relationships to be captured accurately allowing a more realistic analysis. Information generated from a computer based biophysical simulation model form the basis of an economic optimisation model with constraints pertaining to environmental targets and water supply limits. The economic model consists of a linear programming and dynamic programming component, and involves the optimisation of resource use from a catchment manager’s perspective, seeking to achieve efficient resource use but at the same time conform to given environmental objectives. This embedded linear and dynamic programming approach was required to determine the optimal intra-seasonal and inter-seasonal water allocation, given various catchment environmental targets. The interdisciplinary approach enables the economic and ecological outcomes of the catchment management policies to be simulated and assessed at a spatially explicit scale, due to the link to Geographical Information Systems (GIS) in the biophysical model. The overall objective was to create a decision-making framework that could be used to determine the least-cost means of meeting environmental targets and resource constraints. The solutions to the analysis are directly applicable to the case study, the Mooki catchment in northern New South Wales (NSW), but with an adaptable framework that can be applied to other catchments. Specific objectives include an evaluation of the possibility of using alternative irrigation systems, as well as an evaluation of the benefits that can be realised by establishing water market, in the light of environmentally-oriented catchment policies for the case study. The economic cost of achieving environmental targets pertaining to environmental flow requirements and salinity reduction, in the form of end-of-valley salinity targets, was explicitly calculated through the economic model. While salinity targets have been set for NSW catchments, the practicality of such targets is in question, given the substantial reductions in water allocation to irrigation activities, which is one of the key contributors to deep-drainage. An additional objective in this study was therefore to investigate the value of having deep drainage targets. A further consideration is the effect of “external agents” in the form of government plans to buyback entitlements from irrigation districts, or the possibility of significant water rights purchases from mining industries. The implications of external water market entrants on the regional agricultural industry were examined.
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Lee, Lisa Yu-Ting. "EFFICIENT WATER ALLOCATION IN A HETEROGENEOUS CATCHMENT SETTING". University of Sydney, 2007. http://hdl.handle.net/2123/2466.
Texto completoResumen
Doctor of PhilosophyThe problem of water scarcity has become one of the most controversial topics in Australia over the past decades, with particular focus being the ‘sustainable’ allocation of water between extractive and environmental purposes. Geographical factors are defining the extreme variability in climate and water supply in Australia and, in the past, this was used as a rationale for the construction of large irrigation projects to deliver water to rural, urban, and industrial users. During this ‘expansionary’ phase of Australia’s water use sector, the cost of augmenting supply was relatively low and environmental considerations were secondary to the development imperative. As a result, water resources became over-allocated for extractive uses spurred on by consistent underpricing of water, which indicated a failure to reflect the true cost of water supply. As Australia’s water economy entered a ‘mature’ phase, it was no longer possible to increase supply cheaply as the most easily accessible water resources had already been captured. This was followed by widespread environmental degradation manifested in the Murray- Darling Basin, the nation’s largest river basin which hosts much of Australia’s agricultural production. Consequently, the focus shifted towards demand management, leading to a myriad of regulation aimed at increasing the allocative efficiency of scarce water resources. Towards this end, substantial government funding was injected into the various initiatives throughout the water reform process. Despite the on-going government activities in the area of water reform, the understanding of the actual economic impact and environmental outcomes of various water policies in practice remains limited. In the absence of such understanding, the effectiveness of various government water initiatives is ambiguous and inevitably compromised. The present study addresses this knowledge gap by establishing a method for evaluating the economic and environmental outcomes of environmentally-oriented polices that affect irrigated industries in a catchment. The method is based on an integrated biophysical and economic modelling approach, which enables spatial relationships to be captured accurately allowing a more realistic analysis. Information generated from a computer based biophysical simulation model form the basis of an economic optimisation model with constraints pertaining to environmental targets and water supply limits. The economic model consists of a linear programming and dynamic programming component, and involves the optimisation of resource use from a catchment manager’s perspective, seeking to achieve efficient resource use but at the same time conform to given environmental objectives. This embedded linear and dynamic programming approach was required to determine the optimal intra-seasonal and inter-seasonal water allocation, given various catchment environmental targets. The interdisciplinary approach enables the economic and ecological outcomes of the catchment management policies to be simulated and assessed at a spatially explicit scale, due to the link to Geographical Information Systems (GIS) in the biophysical model. The overall objective was to create a decision-making framework that could be used to determine the least-cost means of meeting environmental targets and resource constraints. The solutions to the analysis are directly applicable to the case study, the Mooki catchment in northern New South Wales (NSW), but with an adaptable framework that can be applied to other catchments. Specific objectives include an evaluation of the possibility of using alternative irrigation systems, as well as an evaluation of the benefits that can be realised by establishing water market, in the light of environmentally-oriented catchment policies for the case study. The economic cost of achieving environmental targets pertaining to environmental flow requirements and salinity reduction, in the form of end-of-valley salinity targets, was explicitly calculated through the economic model. While salinity targets have been set for NSW catchments, the practicality of such targets is in question, given the substantial reductions in water allocation to irrigation activities, which is one of the key contributors to deep-drainage. An additional objective in this study was therefore to investigate the value of having deep drainage targets. A further consideration is the effect of “external agents” in the form of government plans to buyback entitlements from irrigation districts, or the possibility of significant water rights purchases from mining industries. The implications of external water market entrants on the regional agricultural industry were examined.
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Fox, Neil Ian. "Estimation of catchment flood potential using satellite data". Thesis, University of Salford, 1998. http://usir.salford.ac.uk/42989/.
Texto completoResumen
A project was undertaken to develop a system to predict the probability of a flood occurring on a particular river catchment as a result of convective storm rainfall, The system is designed for use in developing countries and uses data from the Advanced Very High Resolution Radiometers (AVHRR) aboard the NOAA polar orbiters and the synthetic aperture radar (SAR) of the ESA ERS satellites. The system uses data from the SAR to determine soil moisture content (SMC). From observed differences in SMC it is possible to estimate the evapotranspiration at the surface. In combination with AVHRR derived net radiation, the evapotranspiration,in turn, is used to calculate the sensible heat flux. The sensible heat flux is used in a simple convective model to estimate the height of the atmospheric boundary layer and the velocity of an ascending parcel of air. From this the probability of convective storm occurrence and maximum rainfall is calculated. By inputting the rainfall into a simple, lumped hydrological model the flood potential is found. The system has been tested on two catchments: The River Irwell in Northwest England and the Kafue River in Zambia with good results. Investigations have been made into the advantages of combining the satellite-derived fields with those produced by numerical weather prediction models and some aspects of the system are observed to benefit from this approach.
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Carrillo, Soto Gustavo Adolfo. "Catchment Similarity of Hydrologic Partitioning Along Climate Gradients". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/242371.
Texto completoResumen
Climate variability and landscape characteristics interact to define specific catchment hydrological response. Catchments are considered fundamental landscape units to study the water cycle, since all aspects of the land surface component of the hydrological cycle come together in a defined area, which enables scientific research through mass, momentum and energy budgets. The role of climate-landscape interactions in defining hydrologic partitioning, particularly at the catchment scale, however, is still poorly understood. In this study, a catchment scale process-based hydrologic model (hillslope storage Boussinesq- soil moisture model, hsB-SM) was developed to investigate such interactions. The model was applied to 12 catchments across a climate gradient. Dominant time scales (T.S.) of catchment response and their dimensionless ratios were analyzed with respect to climate and landscape features to identify similarities in catchment response. A limited number of model parameters could be related to observable landscape features. Several T.S. and dimensionless numbers show scaling relationships with respect to the investigated hydrological signatures (runoff coefficient, baseflow index, and slope of the flow duration curve). Some dimensionless numbers vary systematically across the climate gradient, pointing to the possibility that this might be the result of systematic co-variation of climate, vegetation and soil related T.S. Each of 12 behavioral hsB-SM models were subsequently subjected to each of 12 different climate forcings. Mean deviations from Budyko's hypothesis controlling long-term hydrologic partitioning (represented by the evaporation index, E/P, dependence on the aridity index, PET/P) were computed per catchment and per climate. The trend observed per catchment could be explained by the dimensionless ratio of perched aquifer storage-release T.S. and mean storm duration T.S. The trend observed per climate could be explained by an empirical relationship between fraction of rainy days and average daily temperature during those days. Catchments that produce more E/P have developed in climates that produce less E/P, when compared to Budyko's hypothesis. Also, climates that give rise to more E/P are associated with catchments that have vegetation with less efficient water use parameters. These results suggest the possibility of vegetation and soil co-evolution in response to local climate leading to (catchment scale) predictable hydrologic partitioning.