Dissertations / Theses: 'River systems'

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Rushworth, Alastair M. "Flexible regression for river systems." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5267/.

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Maintaining river health is of vital importance to the human populations that depend on them for drinking water, and for the income generated from industry and leisure activities. The key to a clear understanding of the current state of the river environment lies in assimilating the various data that are available for a particular river catchment. As a result of the large expense involved in extensive data collection programmes, measurements are often only taken at a handful of monitoring locations, resulting in large portions of a river network remaining unmonitored and rendering it difficult to assess the health of the river as a whole. Interpreting observations associated with a particular response variable pivots on understanding many other variables whose underlying relationships are often highly complex and which may not be routinely measured. Cutting-edge statistical methods can play a crucial role in the interpretation of such data, particularly when faced with small sample sizes and the presence of latent processes. In particular, developing models for environmental data that relax the assumption of simple linear dependencies between response and covariate is a core theme of this thesis, which can enable powerful descriptions of such complex systems. This approach adopts and promotes modern flexible regression techniques based on penalised splines, which are motivated and summarised in Chapter 2; these permit regression relationships to assume a wide variety of non-linear shapes, without requiring the modeller to impose a priori structure. This thesis aims to address two related, but distinct regression problems for data collected within a river catchment. Firstly, the relationship between rainfall data collected at a rain gauge and subsequent river flow rates collected at a point downstream is tackled in Chapter 3. In this application, it is of particular interest to understand the degree, duration and time-lag of the influence of a rainfall event on a measurable increase in river flow rates at a downstream location. This relationship is complex because it is governed by attributes of the surrounding river environment that may not be readily available, such as soil composition, land use and ground strata. However, rainfall and flow data are frequently collected at a high temporal resolution, and Chapter 3 develops models that exploits this feature that are able to express complex lagged dependence structures between a sequence of flow rates and a rainfall time series. The chapter illustrates how the resulting model enables insight into the sensitivity of the river to additional rainfall, and provides a mechanism for obtaining predictions of future flow rates, without recourse to traditional computationally intensive deterministic modelling. This thesis also tackles the problem of constructing appropriate models for the spatial structure of variables that are carried by water along the channels of the river network. This problem cannot be approached using traditional spatial modelling tools due to the presence of the different volumes of water that mix at confluence points, often causing sudden changes in the levels of the measured variable. Very little literature is available for this type of spatial problem, and none has been developed that is appropriate for the large data sets that are becoming increasingly common in many environmental settings. Chapters 4 and 5 develop new regression models that can incorporate spatial variation on a stream network that respects the presence of confluences, flow rates and direction, while including non-linear functional representations for the influence of covariates. These different model components are constructed using the same modern flexible regression framework as used in Chapter 3, and the computational benefits of adopting this approach are highlighted. Chapter 4 illustrates the utility of the new models by applying them to a large set of dissolved nitrate concentrations collected over a Scottish river network. The application reveals strong trends in both space and time, and evidence of a subtle interaction between temporal trend and the location in space; both conclusions would have been difficult to reach using other techniques.

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Andrews, Matthew B. (Matthew Bryan) 1981. "Natural attenuation of organophosphates in river systems: Chattahoochee River case study." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30138.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.
Includes bibliographical references.
Three organophosphoric acid triesters, tributyl phosphate (TBP), tris(2-chloroethyl) phosphate (TCEP), and tris(2-butoxyethyl) phosphate (TBEP) have been detected in surface waters across the world, primarily the result of sewage treatment plant discharge. Despite concentrations as low as a few parts per trillion, there is growing concern over the potential impact these compounds can have on human and environmental health. This study is an attempt to identify the presence of natural removal processes for these three organophosphoric acid triesters within the Chattahoochee River near Atlanta, Georgia, USA. Samples were collected during the month of January at various sites along the Chattahoochee River. They were subsequently analyzed for concentration of all three organophosphoric acid triesters. These concentrations were then implemented in the construction of mass balances with the intention of identifying a sink term for each compound. A separate set of samples were collected and analyzed at various times over a 24-hour period. These results were used to calculate a biodegradation rate for each organophosphoric acid triester within the Chattahoochee River. The results demonstrate that these three compounds are persistent in the Chattahoochee River over the course of one day. This conclusion is specific to the time of year and location of sampling. Despite findings of no significant natural attenuation, this study should be used as a foundation for future research into the removal of low-level contaminants within the Chattahoochee River.
by Matthew B. Andrews.
M.Eng.

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Langham, Joseph Anthony. "Self organisation in braided systems : DEM analysis of the River Feshie, Scotland." Thesis, University of Hull, 2004. http://hydra.hull.ac.uk/resources/hull:8093.

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Hattingh, Keaton Jade. "Geomorphological controls on pool formation and pool persistence in non-perennial river systems." University of the Western Cape, 2020. http://hdl.handle.net/11394/7739.

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>Magister Scientiae - MSc
Globally climate variability and anthropogenic effects are causing more perennial rivers to become non-perennial rivers. Non-perennial rivers are distinguished by their isolated pools which serve as refugia for aquatic organisms, water birds, and riparian vegetation. The literature on non-perennial rivers demonstrates that pools are poorly understood in terms of their location, nature, and geomorphic persistence. Therefore, this study examines the relationships between the spatial distribution, morphology, and substrate characteristics of pools in reaches of the Prins and Touws rivers in the Klein Karoo. A greater understanding of pools will facilitate better management, monitoring, and restoration strategies for pool ecology since the geomorphology of pools provides a key part of the ecological template. Worldview-2 satellite imagery (2017) and orthorectified aerial photography (2014, 2013, and 1944) were used to assess the effects of major flooding events on pools over time. A DGPS (Differential Global Positioning System) was used to survey the pool widths, lengths, depths, and valley widths, cross-sections, and longitudinal profiles of the river. Sediment samples and Wolman pebble counts were used to assess the grain size and organic matter content of each pool in the study area. Detailed descriptions of the characteristics of each pool in terms of position in the channel, valley form, and obstruction presence and type were also assessed. Results indicate that most of the large pools occur at bedrock outcrops of the valley margins, and smaller pools are associated with Vachellia karroo debris bar features. Larger and highly persistent pools are associated with valley confinement and smaller less persistent, scour pools occur mid-channel where the valley expands. Analysis of the results shows that the valley width is the dominant control on these forced pools. The type of obstruction also plays a role in the formation of the pool as large woody debris results in smaller pools whereas, bedrock outcrops result in larger sized pools. A significant relationship was found between the grain size and organic matter content of pools. Aerial photography of the spatial distribution of the pools revealed that before a major flood, the pools were small and patchy, whereas afterward, they were larger and more elongated. It is suggested that at the bedrock outcrops, major scouring and eddy processes drive the formation of larger pools during large flood events, whereas pool dissection by sediment deposits prevails during intervening intermediate to low flow periods. The results are discussed in terms of the geomorphic controls (valley width, pool dimensions, morphology, substrate, and obstruction characteristics) on the formation and maintenance of pools in dryland settings. A conceptual model is proposed to explain the geomorphic changes of the pools in the four geomorphological zones of non-perennial rivers.

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Jenkins, William Owen. "Decision support systems in river basin management." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47123.

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Visser, Alwyn Jacobus Christiaan. "Real-time management of river systems by using a hydrodynamic model with optimisation." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5438.

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Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: In this research a Real-Time hydrodynamic optimisation model of the Orange-Fish-Sundays River (OFS) system which uses real-time data in order to forecast release hydrographs, is evaluated. The OFS system stretches over three catchment areas in the Eastern Cape namely Great Fish, Little Fish and Sundays Rivers. The OFS supplies water from the Orange River through a 800 km system of canals, tunnels, dams and rivers to registered water users in this area. In order to cope with increasing pressures on water saving, water demand, water quality and dam safety, the Department of Water Affairs implemented this Orange Fish Sundays-Real Time (OFS-RT) system to calculate the optimal water flow, by running customised Danish Hydraulic Institute (DHI) MIKE11 software. The system utilizes an optimisation module that evaluates the simulated outcome at seven water release structures (dams, weirs and tunnels). Then during the optimisation process performs more adjustments to reach the objectives of the system to obtain the forecast release hydrographs. This OFS-RT model aims at target based objectives, using: (i) Hydras real-time field data of dam water levels, river flows and water quality from the area sent to the control office main computer at four hourly intervals via SMS and (ii) abstractors weekly water requests. This system takes irrigation and domestic demand into account as well as water quality, evaporation, rainfall, dam levels, dam safety, instream flow requirements and tributary flow. In order to manage the water flows through the OFS system the OFS-RT model forecasts the release hydrographs and uploads the predictions to a website to smooth operational procedures. The target outcomes were tested and evaluated during this research and it was found that the OFS- RT model succeeded in delivering release forecasts for the seven control structures to manage the OFS system. This research proved that management of river systems by using a real-time hydrodynamic model with optimisation is a useful tool for the optimal utilisation of water resources.
AFRIKAANSE OPSOMMING: Die doel van hierdie navoring is die evaluering van „n intydse hidrodinamiese optimiseringsmodel van die Oranje-Vis-Sondagsrivier (OVS) stelsel wat intydse data ontvang en loslatings hidrograwe verskaf. Die OVS stelsel strek oor drie opvangsgebiede in die Oos-Kaap: naamlik die Groot Vis-, Klein Vis- en Sondagsriviere en voorsien water vanuit die Oranjerivier deur „n 800 km stelsel van kanale, tonnels, damme en riviere, aan geregistreerde waterverbruikers in die gebied. Ten einde te voldoen aan die eise van waterbesparings, stygende vraag na water, die verskaffing van goeie water gehalte en damveiligheid, het die Departement van Waterwese „n intydse rekenaar model (OVS-IT) geïmplimenteer om die optimale watervloei deur middel van die aangepaste MIKE11 sagteware van die Danish Hydraulic Institute (DHI) te bereken. Hierdie stelsel maak gebruik van „n optimisering module wat die gesimuleerde uitkomste van verstellings aan sewe waterloslatingstrukture evalueer. Met optimisering word die verlangde hidrograaf deur verder aanpassings verkry. Data wat nodig is om die OVS-IT model se doel te bereik is: (i) Hydras intydse velddata van damwatervlakke, riviervloeie en water gehalte van die gebied ontvang deur die beheerkantoor se hoofrekenaar via SMS elke vier ure, en (ii) water verbruikers se weeklikse wateraanvrae Die stelsel neem die besproeiing en huishoudelike aanvraag in ag, sowel as soutgehalte, verdamping, reënval, damvlakke, dam veiligheid, stroom vloei vereistes en sytak byvloei. Die OVS se watervloei word beheer deur voorspelde loslatings hidrograwe, opgesom op „n webwerf wat die uitvoer prosedures aandui. Die intydse hidrodinamiese model met optimisering het volgens hierdie navorsing daarin geslaag om vir die beheer van die OVS stelsel, die loslatings van sewe beheerstrukture akkuraat te voorspel en bevind dat die model „n waardevolle instrument is vir die optimale bestuur van waterhulpbronne.

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Busuttil, Marie. "Hydro power scheduling in multi-owner river systems." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10009.

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Silveira, André Filipe. "Polycentricity and the adaptive capacity of river basin governance systems : insights from the River Rhine and the Pearl River (Zhujiang)." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708546.

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Parsons, Melissa, and n/a. "Scales of macroinverterbrate distribution in relation to the hierarchical organisation of river systems." University of Canberra. Science & Design, 2001. http://erl.canberra.edu.au./public/adt-AUC20061113.150809.

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The distribution of macroinvertebrate communities is influenced by a myriad of abiotic environmental factors. However, many of these environmental factors do not occur randomly within a river system. Rather, they occur as a result of geomorphological processes that operate hierarchically to constrain the expression of environmental factors at successively nested levels. As a result of the hierarchical expression of geomorphological processes, environmental factors occur at characteristic scales within a river system and can be used to define spatial scales of river system organisation. Previous studies have examined multiscale patterns of benthic macroinvertebrate community distribution using scales of measurement such as ecoregions, catchments, rivers, reaches and functional habitats. However, none of these studies used scales derived from a geomorphological hierarchy to examine patterns of macroinvertebrate distribution. Given that macroinvertebrates are often deterministically influenced by environmental factors, and these environmental factors occur at characteristic scales within a geomorphological hierarchy, it is possible that the multiscale distribution of macroinvertebrate communities may correspond to the hierarchical arrangement of a river system. This study used scales of measurement derived from a geomorphological hierarchy to examine whether there was any congruence between the distribution of macroinvertebrate communities and the organisation of a river system at the catchment, zone, reach and riffle scales. The Upper Murrumbidgee River Catchment study area (13 005km/2) was divided into catchments, zones within catchments, reaches within zones and riffles within reaches. Macroinvertebrate collection was stratified across these scales according to a balanced nested hierarchical design, and environmental data were also collected at the catchment, zone, reach and riffle scales. Simultaneous multiscale treatment of biological and environmental data allowed identification of multiscale patterns of macroinvertebrate distribution in relation to the hierarchical organisation of a river system, as well as identification of hierarchical interactions between macroinvertebrate communities and environmental factors. Multivariate (ANOSIM, classification, ordination) and univariate (Nested ANOVA) statistical techniques were employed, and each analysis was performed at the species and family levels of taxonomy. Macroinvertebrate communities were highly similar within a reach, because this is the point in the geomorphological hierarchy where environmental conditions become more homogeneous, relative to larger scales. Conversely, communities were dissimilar at the larger zone and catchment scales because environmental conditions become more heterogeneous, relative to smaller scales. However, the reach within zone scale also represents the point where sampling reaches become distinct across the landscape, and the similarity of macroinvertebrate communities within a reach may also be related to the spatial proximity of samples. Hence, macroinvertebrate community distribution is only congruent with the smaller scales of river system organisation. Despite the lack of congruence between macroinvertebrate community distribution and the larger catchment and zone scales of river system organisation, there was a strong regional pattern of distribution in the Upper Murrumbidgee River Catchment. This regional-scale pattern self-emerges from biological information, and is larger than the geomorphologically derived catchment scale. Partitioning of macroinvertebrate data into regional groups subsequently revealed some congruence between macroinvertebrate distribution and the catchment and zone scales of river system organisation. An alternative hierarchy consisting of biological regions, biological clusters, geomorphological reaches and geomorphological riffles was marginally better able to capture patterns of macroinvertebrate distribution than the original catchment, zone, reach and riffle scales. Thus, consideration of the hierarchical organisation of stream systems from a purely physical perspective may fail to encompass scales that are relevant to biota, and biological information should be included as a primary hierarchical component of landscape-scale studies of macroinvertebrate distribution. The pattern of region and reach-scale macroinvertebrate distribution was matched by a general pattern of large catchment and local reach-scale environmental influence. This occurred despite testing of catchment, zone, reach and riffle-scale environmental variables against both the scaled and non-scale pattern of macroinvertebrate distribution. Macroinvertebrate communities were influenced by local reach-scale characteristics such as riparian vegetation character and channel morphology, but rifflescale hydrological variables were also associated with some headwater communities. However, macroinvertebrate communities also sit within a broader landscape context and are influenced by large catchment-scale factors such as landuse, or by factors indicating the geographical position of the sample or the size of the stream. The large and local-scale environmental variables that influence macroinvertebrates are related within a geomorphological hierarchy, and macroinvertebrates may respond deterministically to the same type of environmental factor expressed at different scales. These responses should not be treated as statistical correlates, but rather, they should be viewed in the context of a hierarchy of river system organisation. There was little difference in the overall scale-related findings between species and family level. Family-level macroinvertebrate communities were similar within a reach and dissimilar among reaches, zones and catchments and there was a large regionalscale pattern of family-level community distribution. Local reach-scale and large catchment-scale environmental factors were most strongly associated with family-level macroinvertebrate distribution. Replication of these scale-related findings at both levels of taxonomy indicates that aggregation from species to family level does not result in loss of ecological information pertaining to primary hierarchical patterns. However, the difference between species and family level was pronounced when tracing the hierarchical occurrence of individual taxa, in the context of theories such as the landscape filters hypothesis and habitat based model. In particular, there was a shift in the scale at which families began to be removed from the hierarchy from the region to the smaller cluster scale. This shift was related to the lowered distinctiveness of familylevel regional macroinvertebrate groups, but also suggests that environmental filters may act differently on species and families. The use of family-level data is not recommended for the testing of theories of hierarchical taxon occurrence, because these theories rely on the accurate detection of precise macroinvertebrate-environment relationships. The use of scales of measurement derived from a geomorphological hierarchy provides a process-based foundation for marrying the biological and physical domains, and for examining the hierarchical interactions that may occur between these domains. However, the results of this study indicate that overlaying the biological and physical domains is not a straightforward task, because the biological domain may be influenced by factors other than the deterministic relationship between macroinvertebrates and environmental conditions. Regardless, this study has taken some basic principles of fluvial geomorphology and incorporated them into the design of a standard stream ecology study. Given the relatively advanced state of knowledge that exists individually in the disciplines of fluvial geomorphology and stream ecology, integration and application of concepts across disciplines represents an exciting future opportunity in aquatic science.

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Furse, Michael T. "The faunal richness of headwater streams." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286013.

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Macdonald, Amy. "Does Light Control Algal Abundance in Large River Systems?" VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1622.

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A limited amount of research has been done to investigate the factors influencing algal abundance in large river systems. This study examines light as the primary factor that controls algal abundance in the Upper Mississippi, Missouri and Ohio Rivers. Data were collected for 2004 in conjunction with the Environmental Monitoring Assessment Program- Great River Ecosystems EMAP-GRE project using EPA approved methods. Chlorophyll a concentrations were 34.6 µg•L-1 in the Upper Mississippi, 19.8 µg•L-1 in Missouri River and 9 µg•L-1 in the Ohio River for 2004. Chlorophyll a concentrations were significantly different among the three rivers (p<0.0001) but not between years. Inter-river variation could be loosely correlated with light availability: mean Average Irradiance Dosages, which consider factors that affect light climate (depth, transparency, velocity, surface irradiance), by river corresponded with mean chlorophyll a levels by river. Intra-river variation seemed to be due to both the influence of light and nutrients.

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Summerside, Scott Evan. "Systems analysis of upper San Pedro River Basin conflicts." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/192127.

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A potential for conflict exists over water management and allocation in the Upper San Pedro River Basin. Competing demands for limited water supplies have resulted in concerns about the depletion of the ground-water supplies, reductions in stream flow, and downstream obligations associated with the Gila River Adjudication. A network flow model is an effective tool for analyzing the nature of these water conflicts and evaluating how the introduction of new management strategies can ameliorate the problems. Analysis of water management reveals that concerns about the water problems are valid. Irrigation wells pumping ground water from the floodplain aquifer reduce stream flows that are both necessary for the viability of San Pedro riparian ecosystem, and claimed by downstream Indian tribes. They also contribute to the ground-water overdraft situation in the regional aquifer. Water management alternatives that limit or reduce irrigation consumption are the most effective in rectifying the problems.

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Kneis, David. "A water quality model for shallow river lake systems and its application in river basin management." Phd thesis, [S.l.] : [s.n.], 2007. http://opus.kobv.de/ubp/volltexte/2007/1464.

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Gomes, Daniel Dantas Moreira. "Gis applied to analysis and zoning systems environment of the river MundaÃ River Basin - PE / AL." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=17248.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Given the population growth, technological development and the increasing demand for natural resources becomes clear the importance of the rational and sustainable use of these resources, mainly in the Northeast region of Brazil, which has a major imbalance between supply and demand water and suffer with various problems related to inappropriate land use. Analysis and zoning of different environmental systems, aided by geoprocessing tools, serve as input for land use planning, allowing knowledge and a better use of the potential environmental and reducing the negative effects caused by the inappropriate use of natural resources. Noting the foregoing, it is intended to carry out an analysis and zoning of environmental systems in the watershed of the MundaÃ River (BHRM) - Pernambuco / Alagoas using geoprocessing and empirical models for determination of environmental vulnerability, identifying the main negative environmental impacts and propose a Geoenvironmental zoning model of the study area. The thesis is organized into seven sections, the first section presents the introduction of the research, justifying the relevance of the subject, exposing the thesis objectives, the organizational structure of the same, the literature review and theoretical foundations, and finally is held a demonstration of the technical and methodological procedures. The second section seeks to assess the morphometry of the basin of the MundaÃ River, at this stage, the morphometric characteristics were grouped according to their properties: linear analysis, areal analysis and hypsometric analysis, where the linear attributes involve the drainage network and its spatial arrangement in the basin. To detail the study was considered the characterization of the basin of the MundaÃ River and its sub-basins where each was analyzed individually. The third section was elaborated the mapping and characterization of geomorphic units of the watershed of the MundaÃ River, interpreting the relief forms using different scales of identification and analysis. The elaborate geomorphological compartmentation considers the first four taxonomic levels of relief, where the morphogenetic processes and morphodynamics of the river basin were observed. In the fourth section was prepared mapping coverage and land use in the watershed study, serving as a planning tool and guidance for decision-making. On Thursday seeks to assess section, with the help of GIS techniques, environmental systems in the mentioned river basin, from the systematization and the interrelationship that exists between society and nature from the perspective of rational use of Geoenvironments, taking into account the capabilities and vulnerabilities. The sixth section we sought to establish a proposal for environmental zoning, using empirical models, through interpretation of remote sensing products and field analysis. Finally in the seventh section are made final thesis considerations.
Tendo em vista o aumento populacional, o desenvolvimento tecnolÃgico e a crescente demanda pelos recursos naturais torna-se clara a importÃncia do uso racional e sustentÃvel desses recursos, principalmente para a regiÃo Nordeste do Brasil, que apresenta um grande desequilÃbrio entre a oferta e a demanda de Ãgua, alÃm de sofrerem com diversos problemas relacionados ao uso inapropriado do solo. A anÃlise e zoneamento de diferentes sistemas ambientais, auxiliados pelos usos de ferramentas de geoprocessamento, servem como subsÃdio para um ordenamento territorial, permitindo um conhecimento e um melhor aproveitamento das potencialidades ambientais e diminuindo os efeitos negativos ocasionados pelo uso inadequado dos recursos naturais. Observando o que foi exposto, pretende-se realizar uma anÃlise e zoneamento dos sistemas ambientais na bacia hidrogrÃfica do Rio MundaÃ (BHRM) â Pernambuco/Alagoas, utilizando tÃcnicas de geoprocessamento e modelos empÃricos para determinaÃÃo da vulnerabilidade ambiental, identificaÃÃo os principais impactos ambientais negativos e propor um modelo de zoneamento geoambiental da Ãrea em estudo. A tese estÃ organizada em sete seÃÃes, na primeira seÃÃo apresenta-se a introduÃÃo da pesquisa, justificando a relevÃncia do tema, expondo os objetivos da tese, a estrutura de organizaÃÃo da mesma, a revisÃo de literatura e fundamentaÃÃes teÃricas, e por fim Ã realizada uma demonstraÃÃo dos procedimentos tÃcnicos e metodolÃgicos. A segunda seÃÃo busca avaliar a morfometria da bacia hidrogrÃfica do Rio MundaÃ, nessa etapa, as caracterÃsticas morfomÃtricas foram agrupadas segundo suas propriedades em: anÃlise linear, anÃlise areal e anÃlise hipsomÃtrica, onde os atributos lineares envolvem a rede de drenagem e seu arranjo espacial dentro da bacia. Para detalhar o estudo foi considerada a caracterizaÃÃo da bacia do Rio MundaÃ e suas sub-bacias, onde cada uma foi analisada individualmente. A terceira seÃÃo elaborou-se o mapeamento e caracterizaÃÃo das unidades geomorfolÃgicas da bacia hidrogrÃfica do Rio MundaÃ, interpretando as formas do relevo utilizando diferentes escalas de identificaÃÃo e anÃlise. A compartimentaÃÃo geomorfolÃgica elaborada considera os quatros primeiros nÃveis taxonÃmicos de relevo, onde foram observados os processos morfogenÃticos e a morfodinÃmica da bacia hidrogrÃfica. Na quarta seÃÃo foi elaborado o mapeamento da cobertura e do uso da terra da bacia hidrogrÃfica em estudo, servindo como ferramenta de planejamento e de orientaÃÃo Ã tomada de decisÃo. Na quinta seÃÃo busca-se avaliar, com o auxÃlio das tÃcnicas de geoprocessamento, os sistemas ambientais na mencionada bacia hidrogrÃfica, a partir da sistematizaÃÃo e da inter-relaÃÃo que se dÃ entre Sociedade-Natureza na perspectiva do uso racional dos geoambientes, levando em consideraÃÃo as potencialidades e vulnerabilidades. A sexta seÃÃo buscou-se estabelecer uma proposta de zoneamento ambiental, utilizando modelos empÃricos, atravÃs de interpretaÃÃo de produtos de sensoriamento remoto e anÃlise de campo. E por fim na sÃtima seÃÃo sÃo feitas as consideraÃÃes finais da tese.

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Kerr, Jason Grainger. "The Transformation of Catchment Phosphorus in Dry Subtropical River Systems." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/366275.

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Phosphorus (P) derived from catchment sources is a key factor in the eutrophication of many aquatic ecosystems. Increasingly the protection of receiving waters has been focused on improving water quality through changing land management to decrease the supply of nutrients from the catchment. Rivers are an important link between management actions in the catchment and water quality downstream and therefore an understanding of P dynamics in river systems is central to describing and predicting P fluxes through the catchment. Much of the knowledge about P transformations and transport in rivers comes from studies of temperate systems and to date there have been no studies which define the underlying drivers of P dynamics in dry subtropical rivers. This thesis addresses this gap in knowledge by describing P dynamics in the upper Brisbane River (UBR), a grazing impacted, dry subtropical, river system. A conceptual model of P dynamics was proposed which described the key processes occurring in dry subtropical rivers in the context of the highly variable flows which characterize these systems. The model focuses on three key phases; a drawdown phase whereby flow ceases and P dynamics are dominated by biological and chemical processes; a transport phase during event flows where P dynamics are dominated by physical transport processes; and an intermediate phase where P dynamics are governed by the interaction between biological/chemical and physical processes. The model was used to contrast P dynamics in dry subtropical rivers with the more widely studied temperate systems and to provide a framework for the design and interpretation of experiments. Experiments comprised quantification of instream P storage in key ecosystem compartments coupled with P fractionation and P sorption measurements in soils and sediments under varying extremes of river flow. Bed sediments were shown to be the dominant store of P in most sections of the river examined. P storage was measured in the standing biomass (macrophytes, leaf litter and periphyton), bed sediment and water column of five reaches of varying geomorphology and compared to total P fluxes from the river during the wet season of December 2005 to March 2006. Bed sediments contained the majority of P comprising more than 87% of total reach P at four of the five study reaches. Estimated P storage in the top 2 cm of bed sediments (15.8 T) was approximately 6 times greater than total wet season export from the river system (2.7 T), and almost 7 times higher than the P stored in macrophyte biomass (2.3 T). This suggests that the bed sediments may be an important source of particulate P to downstream ecosystems during event flows and a source of P to primary producers (e.g. macrophytes) during periods where inputs to the river system are reduced...
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Ramos, Eunice Pereira. "Energy systems analysis of transboundary river basins in a nexus approach: the Sava river basin study case." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15833.

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Mestrado em Sistemas Energéticos Sustentáveis
Resource management policies are frequently designed and planned to target specific needs of particular sectors, without taking into account the interests of other sectors who share the same resources. In a climate of resource depletion, population growth, increase in energy demand and climate change awareness, it is of great importance to promote the assessment of intersectoral linkages and, by doing so, understand their effects and implications. This need is further augmented when common use of resources might not be solely relevant at national level, but also when the distribution of resources ranges over different nations. This dissertation focuses on the study of the energy systems of five south eastern European countries, which share the Sava River Basin, using a water-food(agriculture)-energy nexus approach. In the case of the electricity generation sector, the use of water is essential for the integrity of the energy systems, as the electricity production in the riparian countries relies on two major technologies dependent on water resources: hydro and thermal power plants. For example, in 2012, an average of 37% of the electricity production in the SRB countries was generated by hydropower and 61% in thermal power plants. Focusing on the SRB, in terms of existing installed capacities, the basin accommodates close to a tenth of all hydropower capacity while providing water for cooling to 42% of the net capacity of thermal power currently in operation in the basin. This energy-oriented nexus study explores the dependency on the basin’s water resources of the energy systems in the region for the period between 2015 and 2030. To do so, a multi-country electricity model was developed to provide a quantification ground to the analysis, using the open-source software modelling tool OSeMOSYS. Three main areas are subject to analysis: first, the impact of energy efficiency and renewable energy strategies in the electricity generation mix; secondly, the potential impacts of climate change under a moderate climate change projection scenario; and finally, deriving from the latter point, the cumulative impact of an increase in water demand in the agriculture sector, for irrigation. Additionally, electricity trade dynamics are compared across the different scenarios under scrutiny, as an effort to investigate the implications of the aforementioned factors in the electricity markets in the region.
As políticas de gestão de recursos são, frequentemente, desenvolvidas e planeadas para fazer face às necessidades específicas de determinados sectores, sem terem em conta os interesses de outros sectores que também utilizam os mesmos recursos. Num cenário de esgotamento de recursos, crescimento populacional, aumento da procura de energia e sensibilização para as mudanças climáticas, é de grande importância promover a avaliação de ligações intersectoriais e, ao fazê-lo, perceber as suas implicações e efeitos. Esta necessidade é ainda maior quando o uso comum de recursos não é relevante apenas a nível nacional mas também quando a distribuição de recursos se alarga a outras nações diferentes. A presente dissertação centra-se no estudo dos sistemas energéticos de cinco países da região sudeste da Europa que partilham a bacia do rio Sava (BRS), recorrendo a uma abordagem da relação água-alimentação(agricultura)-energia. No caso do sector de produção de eletricidade a utilização da água é essencial para a integridade dos sistemas energéticos, pois a produção de energia nos países da BRS provém de duas tecnologias principais que dependem da água: centrais hídricas e térmicas. A título de exemplo, em 2012, da produção de eletricidade dos países da BRS, 37% foi gerada a partir de energia hídrica e 61% produzida por centrais térmoelétricas. Olhando para a BRS, em termos da potência instalada existente, a bacia acomoda cerca de um décimo de toda a potência hidroelétrica instalada e, ao mesmo tempo, contribui com água para os sistemas de arrefecimento de 42% da potência total instalada das centrais térmicas em funcionamento na região. Este estudo integrado do nexus para a energia explora a dependência entre os sistemas energéticos da região com os recursos hídricos da bacia, entre os anos 2015 e 2030. Para tal, foi desenvolvido um modelo do sistema elétrico transnacional para fornecer uma base quantificavel à análise, usando o software de código aberto OSeMOSYS. A análise é feita a três áreas principais: a primeira corresponde ao impacto das estratégias de eficiência energética e energias renováveis no mix energético de produção de eletricidade; a segunda relaciona-se com os potenciais impactos das alterações climáticas, atendendo a previsões de um cenário moderado de mudanças climáticas e, por último, decorrente do ponto anterior, o impacto cumulativo do aumento da procura de água para irrigação no sector agrícola. Este estudo inclui ainda uma comparação da dinâmica da exportação/importação de eletricidade nos diferentes cenários, com o objetivo de investigar as implicações que os fatores mencionados anteriormente poderão ter nos mercados da eletricidade dos países desta região.

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17

Banda, Vincent Santos Dzulani. "Assessing hydrogeological characteristics to establish influence of aquifer-river interaction in non-perennial river systems, Heuningnes catchment." University of the Western Cape, 2019. http://hdl.handle.net/11394/7007.

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>Magister Scientiae - MSc
Over half of total flows in the global river network are composed of non-perennial rivers. This indicates the importance of non-perennial river systems in supporting the biodiversity. It has been established that groundwater is one of the elements that control the flow regimes and classification (whether perennial or not) of a river system. However, the use of hydrogeological characteristics to establish the influence of groundwater on non-perennial river systems remain to be widely unpublished. This study, therefore, intends to conceptualize and explain the role of hydrogeological characteristics in non-perennial rivers, using the Heuningnes catchment in the Western Cape Province of South Africa as a case study. The study has argued that thorough characterization of aquifers is essential in order to adequately establish the extent of aquifer-river connectivity and how groundwater influences flows and chemical loading in non-perennial river systems. The study has three objectives namely: (i) to determine the aquifer characteristics (ii) to characterise the aquifer-river interaction and (iii) to conceptualize the groundwater flow system. Records review, field, analytical and laboratory-based methods were used to collect and interpret geological, groundwater level, pumping test, hydro-chemical and environmental stable isotopic data in order to characterise groundwater occurrence, flow system and its interaction with the rivers of the study area. Water samples were taken from groundwater, surface water and rainfall during both dry and wet periods. Results show that the study area has a topography-controlled water table with shallow depth to groundwater levels ranging on average from 3 - 10 m, which result into largely a local groundwater flow system. Transmissivity values determined from constant rate pumping test range between 0.17 and 1.74 m2/day. Results exhibit that the low transmissivity values are associated with the weathered nature of the Table Mountain sandstone and the unfractured Bokkeveld shale formations. Hydrochemical data results indicate that both groundwater and river samples in the upstream part of the study area are characterised as fresh water with TDS values of less than 1000 mg/l while the downstream part has saline waters with TDS ranging from 2000 – 35000 mg/l. Results also show that Na-Cl is the dominant water composition for both groundwater and river water. The order of major ion dominance is similar for the two water sources, with concentration ranges from high to low in the order of Na+>Mg2+>Ca2+>K+ and Cl->SO42->HCO3- for cations and anions respectively. The similar patterns and trends in salinity and major ion data suggest the connectivity between the aquifer and the river. Environmental stable isotope data indicate river samples in upstream areas having depleted δ18O (-4.3 to -5.12‰) and δ2H (-22.9 to -19.3‰) signatures similar to groundwater indicating a stable and continuous groundwater contribution to the river flows. Meanwhile, high evaporative enrichment of δ18O (1.13 to 7.08‰) and δ2H (38.8 to 7.5‰) is conceived in river samples from downstream areas. Ionic ratios and isotope-salinity relationships suggest that groundwater chemistry is derived from sea sprays, evaporation and dissolution of Bokkeveld shale host rock. Geological, hydrogeological, hydrochemical and environmental stable isotope data were used to develop a conceptual hydrogeological model which explains the role of groundwater in non-perennial river systems. Results indicate that the North East – South West fault on the north-eastern part of the study area seem to act as a conduit to groundwater flow thereby supplying water to the upstream rivers while the East -West fault in the northern part seem to act as a barrier to groundwater flow resulting into a hydraulic discontinuity between upstream and downstream areas. Meanwhile, the relatively low conductive formation in the downstream areas coupled with a relatively low hydraulic gradient (0.000843) suggests there is slow Darcian groundwater flows resulting in less flushing and high salinization of groundwater. Eventually, in the downstream part of the study area there is slow and minimal groundwater discharge to the rivers resulting into groundwater failing to maintain the river flows and pools. In general, rivers of the study area largely gain water from groundwater although the amount of groundwater discharge varies from one river segment to another in both upstream and downstream parts. The conceptual model has led to the development of a proposed optimum management of non-perennial rivers including the effects of groundwater abstraction on the river flows.
2022-09-01

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18

Momoh, Jinnah Samuel. "Decision support system for river water quality forecasting and management." Thesis, University of Newcastle Upon Tyne, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246651.

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19

Linke, Simon, and n/a. "River conservation planning: accounting for condition, vulnerability and connected systems." University of Canberra. Resource, Environmental & Heritage Sciences, 2006. http://erl.canberra.edu.au./public/adt-AUC20070716.155500.

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Conservation science in rivers is still lagging behind its terrestrial and marine counterparts, despite increasing threats to freshwater biodiversity and extinction rates being estimated as five times higher than in terrestrial ecosystems. Internationally, most protected rivers have been assigned reserve status in the framework of terrestrial conservation plans, neglecting catchment effects of disturbance. While freshwater conservation tools are mainly index based (e.g. richness, rarity), modern terrestrial and marine conservation planning methods use complementarity-based algorithms - proven to be most efficient at protecting a large number of taxa for the least cost. The few complementarity-based lotic conservation efforts all use broad river classifications instead of biota as targets, a method heavily disputed in the literature. They also ignore current condition and future vulnerability. It was the aim of this thesis to develop a framework for conservation planning that: a) accounts for the connected nature of rivers b) is complementarity based and uses biota as targets c) integrates current status and future vulnerability I developed two different approaches using macroinvertebrate datasets from Australia, Canada and the USA. The first new method was a site/based two-tiered approach integrating condition and conservation value, based on RIVPACS/AUSRIVAS � a modelling technique that predicts macroinvertebrate composition. The condition stage assesses biodiversity loss by estimating a site-specific expected assemblage and comparing it to the actual observed assemblage. Sites with significant biodiversity loss are flagged for restoration, or other management actions. All other sites progress to the conservation stage, in which an index of site-specific taxonomic rarity is calculated. This second index (O/E BIODIV) assesses the number of rare taxa (as defined by <50% probability of occurrence). Using this approach on a dataset near Sydney, NSW, Australia, I was able to identify three regions: 1) an area in need of restoration; 2) a region of high conservation value and 3) an area that had high conservation potential if protection and restoration measures could counteract present disturbance. However, a second trial run with three datasets from the USA and Canada highlighted problems with O/E (BIODIV). If common taxa are predicted at lower probabilities of occurrence (p<50%) because of model error, they enter the index and change O/E (BIODIV). Therefore, despite an attractive theoretical grounding, the application of O/E (BIODIV) will be restricted to datasets where strong environmental gradients explain a large quantity of variation in the data and permit accurate predictions of rare taxa. It also requires extensive knowledge of regional species pools to ensure that introduced organisms are not counted in the index. The second approach was a proper adaptation of terrestrial complementarity algorithms and an extension to the Irreplaceability-Vulnerability framework by Margules and Pressey (2000). For this large-scale method, distributions for 400 invertebrate taxa were modeled across 1854 subcatchments in Victoria, Australia using Generalised Additive Models (GAMs). The best heuristic algorithm to estimate conservation value was determined by calculating the minimum area needed to cover all 400 taxa. Solutions were restricted to include rules for the protection of whole catchments upstream of a subcatchment that contained the target taxon. A summed rarity algorithm proved to be most efficient, beating the second best solution by 100 000 hectares. To protect 90% of the taxa, only 2% of the study area need to be protected. This increases to 10% of the study area when full representation of the targets is required. Irreplaceability was calculated by running the heuristic algorithm 1000 times with 90% of the catchments randomly removed. Two statistics were then estimated: f (the frequency of selection across 1000 runs) and average c (contribution to conservation targets). Four groups of catchments were identified: a) catchments that have high contributions and are always selected; b) catchments that have high contributions and are not always selected; c) catchments that are always chosen but do not contribute many taxa; d) catchments that are rarely chosen and did not contribute many taxa. Summed c, the sum of contributions over 1000 runs was chosen as an indicator of irreplaceability, integrating the frequency of selection and the number of taxa protected. Irreplaceability (I) was then linked to condition (C) and vulnerability (V) to create the ICVframework for river conservation planning. Condition was estimated using a stressor gradient approach (SGA), in which GIS layers of disturbance were summarised to three principal axes using principal components analysis (PCA). The main stressor gradient � agriculture � classified 75% of the study area as disturbed, a value consistent with existing assessments of river condition. Vulnerability was defined as the likelihood that land use in a catchment would intensify in the future. Hereby current tenure was compared to land capability. If a catchment would support a land use that would have a stronger effect on the rivers than its current tenure, it was classified as vulnerable. 79% of catchments contained more than 50% vulnerable land. When integrating the three estimators in the ICV-framework, seven percent of catchments were identified as highly irreplaceable but in degraded condition. These were flagged for urgent restoration. Unprotected, but highly irreplaceable and highly vulnerable catchments that were still in good condition made up 2.5% of the total area. These catchments are prime candidates for river reserves. The ICV framework developed here is the first method for systematic conservation planning in rivers that is complementarity-based, biota-driven but flexible to other conservation targets and accounts for catchment effects, thus fulfilling all the gaps outlined in the aims.

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Guven, Basak. "Modelling the growth and movement of cyanobacteria in river systems." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428865.

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21

Gibbs, Helen Margaret. "The interactions between macrophytes and sediments in urban river systems." Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8480.

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Many urban rivers receive significant inputs of metal-contaminated sediments from their catchments. Their restoration has the potential to increase the deposition and accumulation of these sediments from greater sediment supply and increased channel hydraulic complexity, creating a store of metals which could have negative impacts upon ecosystems and human health. Macrophytes often establish in restored channels and have the potential to stabilise these sediments and uptake metals through processes of phytoremediation, thus reducing the risk of the accumulated sediments becoming a source of metals. This thesis investigates the effects of river restoration upon sedimentation patterns and the interactions between macrophytes and sediments in terms of sediment trapping, stabilisation and metal uptake within urban river systems. At a reach scale, greater finer sediment deposition and the accumulation of sediment around in-channel vegetation was found within restored stretches of tributaries of the River Thames London, reflecting sediment availability and hydraulic conditions. These sediments were important in terms of greater metal storage within stretches, and along with gravels showed particularly high metal concentrations. Interactions between macrophytes, sediment and flow were investigated within the urban-influenced River Blackwater, Surrey. At the stand scale, the common emergent Sparganium erectum was found to significantly reduce flow velocities, accumulate fine sediments and retain them over winter. Research on individual plants revealed that, although three common emergent macrophytes (Sparganium erectum, Typha latifolia and Phalaris arundinacea) did not significantly phytoremediate metal contaminated sediments through metal uptake or bioconcentration, the reinforcement and stabilisation of these accumulated sediments (particularly by Sparganium erectum and Typha latifolia) and the creation of anoxic sediment conditions which strongly bind metals, were important in reducing the risk of metal mobilisation from the sediments. These macrophyte sediment interactions illustrate the great potential of using emergent macrophytes in the restoration and management of urban rivers with metal contaminated sediments.

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Osei-Twumasi, Anthony. "Integrated modelling studies of solute transport in river basin systems." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54991/.

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Surface water and groundwater systems are linked dynamically in reality as the one generally impacts directly on the other. Traditionally, however, these two water bodies have more often than not been treated as different entities by water managers and other professionals. The issue of the compartmentality of these two resources is the main focus of the study described herein. In this study, an existing 1D-2D hydro-environmental surface water model that includes a groundwater model (DIVAST-SG) has been extended to 2-D and refined through testing against three laboratory studies. A surface water-groundwater system model using foam to replicate groundwater material was created in the laboratory and the results of the hydrodynamic processes (i.e. water elevations and flowpaths) were compared with the numerical model predictions. On the whole the comparisons showed good agreement. However, dye studies for replicating pollutant transport did not show such good agreement and this discrepancy was thought to be due to a number of reasons. In the second series of studies, the groundwater material was then replaced with the more traditional sand embankment and again results for both hydrodynamic and solute transport processes (by way of dye studies) from the laboratory set up were compared with the numerical predictions which were in almost perfect agreement. In the same tidal basin, a Severn Estuary model was then designed and set up. Although there were differences from the prototype owing to space and scaling difficulties, the results showed good agreement for both tidal amplitudes and tidal currents with the predictions from the numerical model and particularly the tidal amplitudes were found to compare favourably with field studies. Tracer results from the physical model also showed consistency with simulations from previous researchers in the main estuary. Overall, the purpose of this study, which was to investigate the manner in which flow and solute (conservative tracer) fluxes interacted between surface and sub-surface flows, for simulated riverine and tidal conditions, has been achieved. These experiments and the corresponding datasets are thought to be unique.

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Alruzuq, Ali Rashed. "SOCIO - HYDROLOGY OF LEVEE SYSTEMS ALONG THE LOWER ILLINIOS RIVER." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2315.

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Levee safety inspections performed in the U.S. under Public-Law 84-99 administered by the U.S. Army Corps of Engineers (USACE) have found ~36% of the participating levee systems have an unacceptable safety rating. This suggests a substantial number of levee systems are not able to keep up with their maintenance. This study seeks to explore if there are differing socioeconomic characteristics between levee systems with acceptable verses unacceptable levee safety ratings to try and assess what characteristics make a system more likely to be sustainable (i.e., possessing an acceptable levee safety rating). In this study, a methodology has been developed using national to regional level socioeconomic data, levee characteristics, and geospatial and statistical analyses to determine if there are differences in socioeconomic factors between levee systems with acceptable verses unacceptable safety ratings. We used this methodology to evaluate 29 levee systems (20 with at least minimally acceptable and 9 with an unacceptable levee safety rating) within the lower Illinois River (LIR) valley. GIS was used to dysameterically map U.S. census and census based block-level socioeconomic data within each of the LIR levee systems. A Principal Components Analysis (PCA) was used to assess which of the socioeconomic variables explained most of the variance between the LIR levee systems. The Mann-Whitney-Wilcoxon U-Test was used to determine if there were statistically significant differences in these socioeconomic variables between levees systems with at least minimally acceptable and an unacceptable levee safety rating. The PCA analysis revealed five components consisting of 19 variables explained 85% of the variance between levee systems. The five components identified were exposure, population, wealth, development, and levee protection characteristics which explained 26.3%, 24.2%, 18.2%, 8.9% and 7.2% of the variance, respectively. The 19 variables which comprised these five components were as follows: levee-protected area, population, percentage non-white, average residential building value, number of residential homes, exposure, percentage of the population between 16 and 64, percentage of the population younger than 16 and older than 64, percentage male, percentage female, percentage white, percentage of the population making more than $40,000, agricultural profit, agricultural profit per acre, average residential building value, percentage of the population making less than $40,000, average per-capita income, and levee-protection level. The Mann-Whitney-Wilcoxon U-Test revealed differences in total population within a levee system, race, average per-capita income, average residential building value, and total population between levee systems with an acceptable verses and unacceptable rating were significant at the α = 0.2 confidence interval. The average per-capita income, percentage of population which is white, average residential building value were all higher on average within levee systems with an unacceptable rating. This seems to suggest populations who inhabit levees with unacceptable safety ratings are white and more wealthy than the communities located within levee systems with at least minimally acceptable ratings. This finding is counter to a large body of research which has shown more vulnerable populations (the poor and poorer minorities) are generally found within areas with higher risk of flooding and other natural hazards. These findings may suggest wealthier floodplain property owners within unacceptable levee systems are foregoing necessary levee maintenance and instead relying on crop insurance and other government programs to pay for future flood damages.

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24

Buckley, Mark C. "The problem of restoring natural systems among social systems : strategic considerations and the Sacramento River /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.

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Buckley, Mark C. Buckley Mark C. "The problem of restoring natural systems among social systems : strategic considerations and the Sacramento River /." Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.

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26

Trinci, Giuditta. "Spatial organisation of ecologically relevant high order flow properties and implications for river habitat assessment." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/30951.

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The turbulent properties of flow in rivers are of fundamental importance to aquatic organisms yet are rarely quantified during routine river habitat assessment surveys or the design of restoration schemes due to their complex nature. This thesis uses a detailed review of the literature to highlight the various ways in which plants and animals modify the flow field, how this can deliver beneficial effects; and how turbulence can also generate threats to growth and survival. The thesis then presents the results from detailed field assessments of turbulence properties undertaken on low, intermediate and high gradient rivers to advance scientific understanding of the hydrodynamics of rivers and inform effective habitat assessment and restoration. A reach-scale comparison across sites reveals spatial variations in the relationships between turbulent parameters, emphasising the need for direct measurement of turbulence properties, while a geomorphic unit scale assessment suggests that variations in turbulence at the scale of individual roughness elements, and/or within the same broad groupings of geomorphic units (e.g. different types of pools) can have an important influence on hydraulic habitat. The importance of small-scale flow obstructions is further emphasised through analysis of the temporal dynamics of turbulence properties with changes in flow stage and vegetation growth. The highest magnitude temporal changes in turbulence properties were associated with individual boulders and vegetation patches respectively, indicating flow intensification around these sub-geomorphic unit scale features. Experimental research combining flow measurement with underwater videography reveals that more sophisticated turbulence parameters provide a better explanation of fish behaviour and habitat use under field conditions, further supporting direct measurement of turbulent properties where possible. The new insights into interactions between geomorphology, hydraulics and aquatic organisms generated by this work offer opportunities for refining habitat assessment and restoration design protocols to better integrate the important role of turbulence in generating suitable physical habitat for aquatic organisms.

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Sill, Paul E. (Paul Eric). "Assessing Regional Gully Erosion Risk: A Remote Sensing and Geographic Information Systems Approach." Thesis, University of North Texas, 1995. https://digital.library.unt.edu/ark:/67531/metadc332453/.

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Gully erosion has been established as a major source of sediment pollution in the upper Trinity River watershed in north-central Texas. This fact, along with a lack of models appropriate for a large-area gully erosion analysis established a need for a gully erosion study in the upper Trinity basin. This thesis project attempted to address this need by deriving an index indicative of gully erosion risk using remote sensing and geographic information systems (GIS) methodology. In context of previous field studies, the coarse spatial resolution of the input GIS data layers presented a challenge to prediction of gully prone areas. However, the remote sensing/GIS approach was found to provide useful reconnaissance information on gully risk over large areas.

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Banerjee, Malini De. "High-Frequency Nitrate Monitoring in Dynamic River Systems: the Case of Three Iowa Rivers in the Mississippi Basin." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/4818.

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High frequency water quality monitoring presents unique and unlimited opportunities of exploring spatio-temporal variation in water quality. Knowledge gained from analyzing high frequency water quality data can provide more clarity regarding transportation and processing of water constituents over time and space and scale. This study analyzes high frequency discharge, nitrate load and concentration data for three watersheds of different sizes - Cedar River Watershed, North Raccoon and Middle Raccoon. Each of these sites were monitored for 2-3 calendar years. Sudden spikes in discharge, nitrate concentration and load data, also defined as "events" were analyzed in great detail to understand the patterns in event occurrence and event intensity. Smaller watersheds seemed to have sharper and "flashier" events compared to bigger watersheds. Nitrate concentration events were flatter in shape compared to discharge and nitrogen load events. The relationship between nitrogen concentration and discharge was found to be varying over time, unlike the relationship between nitrate load and discharge, which were almost perfectly correlated for most site-year combinations. Based on more than 40,000 simulations, it was determined that high frequency water quality sampling is not only efficient in capturing minute spatio-temporal variations but can also capture nitrate exceedances to a greater degree. High frequency sampling was also associated with higher yield ratio in nitrate load estimates, not only during high flow periods, but also during the non-high-flow period.

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Marttila, M. (Maare). "Ecological and social dimensions of restoration success in boreal river systems." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526217253.

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Abstract The degradation of rivers and streams has led to world-wide efforts to restore freshwater habitats. A good understanding of the social-ecological context is considered key to successful restoration. In this thesis, a multidisciplinary framework was applied to study ecological and social dimensions of restoration success. First, the long-term performance of in-stream restoration measures was examined by conducting repeated cross-sectional surveys in restored streams up to 20 years post-restoration. Next, nationwide electrofishing data were used to assess the density responses of juvenile salmonids to habitat restoration and factors influencing restoration success were examined. Finally, changes in the provision of ecosystem services were evaluated by comparing the perceptions of restoration outcomes between two user groups and three study rivers. The results indicated that the restoration-induced increase in habitat heterogeneity persisted over time, initiating an overall positive development also in biological metrics (i.e. juvenile salmonids and aquatic mosses). However, overall substrate variability in restored streams remained lower than in near-pristine streams, with a shortage of gravel beds. Fish responses varied strongly between rivers, which was explained mainly by watershed scale (e.g. river basin size, dominant geology) and local (potential interspecific competition) factors. Site-specific differences were also observed in the delivery of ecosystem services, mainly reflecting stakeholder perceptions of landscape value and fish provisioning. Overall, the results show that setting indicators and target levels for restoration success is grounded on perspective. Socially conscious ecological restoration that acknowledges local specialities and needs in priority setting, planning and implementation has the potential to provide multiple benefits for river ecosystems and society
Tiivistelmä Virtavesien ekologisen tilan heikentyminen on johtanut maailmanlaajuisiin toimiin niiden elinympäristöjen kunnostamiseksi. Usein ekologisen kunnostuksen onnistuminen edellyttää kuitenkin ihmisen ja ympäristön vuorovaikutussuhteiden laaja-alaista ymmärtämistä. Tässä väitöskirjatutkimuksessa käytettiin monitieteistä viitekehystä virtavesikunnostusten ekologisten ja sosiaalisten vaikutusten tutkimiseen. Ensimmäisessä osatyössä arvioitiin kunnostustoimenpiteiden kestävyyttä sekä uoman rakenteellisen monimuotoisuuden kehittymistä pitkällä aikavälillä (10-20 vuotta kunnostusten jälkeen). Toisessa osatyössä tehtiin valtakunnallisen sähkökalastusaineiston avulla meta-analyysipohjainen yhteenveto suomalaisten virtavesikunnostusten vaikutuksista taimenen ja lohen kesänvanhojen (0+) poikasten tiheyteen sekä tutkittiin kunnostustulokseen vaikuttavia ympäristötekijöitä. Kolmannessa osatyössä selvitettiin kunnostusten onnistumista ekosysteemipalvelujen näkökulmasta vertaamalla kahden eri käyttäjäryhmän kokemia muutoksia kolmen tutkimusjoen välillä. Väitöskirjan tulokset osoittivat, että kunnostukset lisäsivät jokiuoman rakenteellista monimuotoisuutta sekä lyhyellä että pitkällä aikavälillä ja vaikuttivat myönteisesti myös biologisiin indikaattoreihin (lohikalojen poikastiheys ja vesisammalet). Vaihtelu pohjan laadussa oli kuitenkin luonnontilaisia uomia vähäisempää ja erityisesti kutuun soveltuvaa soraa oli niukasti. Lohikalojen tiheysvaste vaihteli voimakkaasti jokien välillä, mikä selittyi pääasiassa valuma-alueeseen liittyvillä (esim. valuma-alueen koko ja geologia) ja paikallisilla (mahdollinen lajien välinen kilpailu) tekijöillä. Paikkasidonnaisia eroja havaittiin myös vaikutuksissa ekosysteemipalveluihin ja ne heijastivat etenkin maisemassa ja kalasaaliissa koettuja muutoksia. Tutkimus osoitti, että erilaiset taustat ja odotukset vaikuttavat vahvasti siihen, millaisten kriteerien perusteella kunnostusten onnistumista arvioidaan. Jotta kunnostuksilla saavutettaisiin hyötyjä sekä jokiekosysteemeille että yhteiskunnalle, on tärkeää tuntea paikalliset erityispiirteet ja -tarpeet ja ottaa ne huomioon kunnostuskohteiden valinnassa sekä toimenpiteiden suunnittelussa ja toteutuksessa

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Sabater, Liesa Laia. "Disentangling the complexity of chemical and physical stressors impacting river systems." Doctoral thesis, Universitat de Girona, 2021. http://hdl.handle.net/10803/671769.

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Humanity has always been closely linked to rivers, benefiting from their resources while producing impacts associated with their activity.Thus, river systems have been exposed to multiple stressors, which have affected the quality of water and their biological communities, such as those attached to substrata (biofilms) or those that are suspended in water (phytoplankton). On the other hand, biological communities also respond and contribute to the transformation and/or degradation of certain anthropogenic organic compounds, such as pharmaceuticals. This thesis investigates the chemical state of the river systems and their impacts on the biological communities, using different approaches and scales
La humanitat ha estat sempre íntimament lligada als rius, beneficiant-se dels seus recursos però també produint impactes vinculats a la seva activitat. Així doncs, els sistemes fluvials han estat exposats a múltiples estressos, que han afectat la qualitat de l’aigua així com a l’ecosistema de les seves comunitats biològiques, com les adherides al biofilm o bé les que estan en suspensió a l’aigua, com el fitoplàncton. A més, les comunitats biològiques també responen i contribueixen a la transformació i/o degradació d’alguns compostos orgànics d’origen antropogènic, com els fàrmacs. Aquesta tesi investiga l’estat químic dels sistemes fluvials, i els seus impactes, utilitzant diferents aproximacions i escales
Programa de Doctorat en Ciència i Tecnologia de l'Aigua

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31

Carini, Giovannella, and n/a. "Effects of Contemporary and Historical Processes on Population Genetic Structure of Two Freshwater Species in Dryland River Systems (Western Queensland, Australia)." Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050113.081250.

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Arid and semiarid river systems in Western Queensland, Australia, are characterized by the unpredictable and highly variable nature of their hydrological regimes as a result of the episodic nature of rain events in the region. These dryland rivers typically experience episodic floods and extremely low or no flow periods. During low or no flow periods, water persists only in relatively wide and deep sections of the river channels, which are called 'waterholes'. These isolated waterholes serve as refugia for aquatic species during protracted intervals between floods. In such discontinuous riverine habitat, dispersal of freshwater species may be achieved only during wet seasons, when water is flowing in rivers and the nearby floodplains. Obligate aquatic species occur in habitats that represent discrete sites surrounded by inhospitable terrestrial landscapes. Thus, movements are very much limited by the physical nature and arrangement of the riverine system. In addition, the distribution of a species may be also largely dependent on historical events. Landscape and river courses continually change over geological time, often leaving distinct phylogenetic 'signatures', useful in reconciling species' biology with population connectivity and earth history. The main aim of this study was to resolve the relative importance of contemporary and historical processes in structuring populations of two freshwater species in Western Queensland river systems. To address this aim, a comparative approach was taken in analysing patterns of genetic variation of two freshwater invertebrates: a snail (Notopala sublineata) and a prawn (Macrobrachium australiense). Mitochondrial sequences were used for both the species. In addition, allozyme and microsatellites markers were employed for N. sublineata. These species have similar distributions in Western Queensland region, although N. sublineata appears to be extinct in some catchments. M. australiense is thought to have good dispersal abilities due to a planktonic larval phase in its life cycle and good swimming capabilities, whereas N. sublineata is thought to have limited dispersal abilities, because of its benthic behaviour and because this species is viviparous. It was hypothesised that these freshwater invertebrates, would display high levels of genetic structure in populations, because physical barriers represented by terrestrial inhospitable habitat, are likely to impede gene flow between populations inhabiting isolated river pools. Genetic data for the two species targeted in this study supported this hypothesis, indicating strong population subdivision at all spatial scales investigated (i.e. between and within catchments). This suggests that contemporary dispersal between isolated waterholes is relatively restricted, despite the potential good dispersal abilities of one of the species. It was hypothesised that levels of gene flow between populations of aquatic species were higher during the Quaternary (likely movements of individuals across catchment boundaries) and that they have been isolated relatively recently. There is evidence that historically gene flow was occurring between populations, suggesting that episodic dispersal across catchment boundaries was likelier in the past. Episodic historical movements of aquatic fauna were facilitated by higher patterns of river connectivity as a result of the climate changes of the Pleistocene. Because the two species targeted in this study exhibit analogous spatial patterns of evolutionary subdivision it is likely that they have a shared biogeographic history. The unpredictable flow regime of rivers in Western Queensland is likely to have considerable effects on the genetic diversity of aquatic populations. First, if populations of obligate freshwater organisms inhabiting less persistent waterholes are more likely to experience periodic bottlenecks than those inhabiting more persistent ones, they would be expected to have lower levels of genetic diversity. Second, if populations inhabiting less persistent waterholes periodically undergo local extinction with subsequent recolonisation, there should be higher levels of genetic differentiation among them, due to the founder effects, than among those populations inhabiting more persistent waterholes. Contrary to the first prediction, the observed levels of genetic diversity in both N. sublineata and M. australiense were high in both more persistent and less persistent waterholes. There was no tendency for genetic diversity to be lower in less persistent than in more persistent waterholes. However, when Cooper waterholes were ranked in order of persistence, positive correlation between water persistence time in waterholes and genetic diversity was detected in N. sublineata but not in M. australiense. Contrary to the second prediction, highly significant genetic differentiation was found among populations from both less persistent and more persistent waterholes. This indicates that not only populations from less persistent but also those from more persistent waterholes were very dissimilar genetically. This study demonstrated the importance of both contemporary and historical processes in shaping the population structure of obligate freshwater species in Western Queensland river systems. It has indicated that contemporary movements of freshwater species generally are extremely limited across the region, whereas episodic dispersal across catchment boundaries was possible during the Pleistocene, due to different patterns of river connectivity.

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32

Carini, Giovannella. "Effects of Contemporary and Historical Processes on Population Genetic Structure of Two Freshwater Species in Dryland River Systems (Western Queensland, Australia)." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367070.

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Abstract:

Arid and semiarid river systems in Western Queensland, Australia, are characterized by the unpredictable and highly variable nature of their hydrological regimes as a result of the episodic nature of rain events in the region. These dryland rivers typically experience episodic floods and extremely low or no flow periods. During low or no flow periods, water persists only in relatively wide and deep sections of the river channels, which are called 'waterholes'. These isolated waterholes serve as refugia for aquatic species during protracted intervals between floods. In such discontinuous riverine habitat, dispersal of freshwater species may be achieved only during wet seasons, when water is flowing in rivers and the nearby floodplains. Obligate aquatic species occur in habitats that represent discrete sites surrounded by inhospitable terrestrial landscapes. Thus, movements are very much limited by the physical nature and arrangement of the riverine system. In addition, the distribution of a species may be also largely dependent on historical events. Landscape and river courses continually change over geological time, often leaving distinct phylogenetic 'signatures', useful in reconciling species' biology with population connectivity and earth history. The main aim of this study was to resolve the relative importance of contemporary and historical processes in structuring populations of two freshwater species in Western Queensland river systems. To address this aim, a comparative approach was taken in analysing patterns of genetic variation of two freshwater invertebrates: a snail (Notopala sublineata) and a prawn (Macrobrachium australiense). Mitochondrial sequences were used for both the species. In addition, allozyme and microsatellites markers were employed for N. sublineata. These species have similar distributions in Western Queensland region, although N. sublineata appears to be extinct in some catchments. M. australiense is thought to have good dispersal abilities due to a planktonic larval phase in its life cycle and good swimming capabilities, whereas N. sublineata is thought to have limited dispersal abilities, because of its benthic behaviour and because this species is viviparous. It was hypothesised that these freshwater invertebrates, would display high levels of genetic structure in populations, because physical barriers represented by terrestrial inhospitable habitat, are likely to impede gene flow between populations inhabiting isolated river pools. Genetic data for the two species targeted in this study supported this hypothesis, indicating strong population subdivision at all spatial scales investigated (i.e. between and within catchments). This suggests that contemporary dispersal between isolated waterholes is relatively restricted, despite the potential good dispersal abilities of one of the species. It was hypothesised that levels of gene flow between populations of aquatic species were higher during the Quaternary (likely movements of individuals across catchment boundaries) and that they have been isolated relatively recently. There is evidence that historically gene flow was occurring between populations, suggesting that episodic dispersal across catchment boundaries was likelier in the past. Episodic historical movements of aquatic fauna were facilitated by higher patterns of river connectivity as a result of the climate changes of the Pleistocene. Because the two species targeted in this study exhibit analogous spatial patterns of evolutionary subdivision it is likely that they have a shared biogeographic history. The unpredictable flow regime of rivers in Western Queensland is likely to have considerable effects on the genetic diversity of aquatic populations. First, if populations of obligate freshwater organisms inhabiting less persistent waterholes are more likely to experience periodic bottlenecks than those inhabiting more persistent ones, they would be expected to have lower levels of genetic diversity. Second, if populations inhabiting less persistent waterholes periodically undergo local extinction with subsequent recolonisation, there should be higher levels of genetic differentiation among them, due to the founder effects, than among those populations inhabiting more persistent waterholes. Contrary to the first prediction, the observed levels of genetic diversity in both N. sublineata and M. australiense were high in both more persistent and less persistent waterholes. There was no tendency for genetic diversity to be lower in less persistent than in more persistent waterholes. However, when Cooper waterholes were ranked in order of persistence, positive correlation between water persistence time in waterholes and genetic diversity was detected in N. sublineata but not in M. australiense. Contrary to the second prediction, highly significant genetic differentiation was found among populations from both less persistent and more persistent waterholes. This indicates that not only populations from less persistent but also those from more persistent waterholes were very dissimilar genetically. This study demonstrated the importance of both contemporary and historical processes in shaping the population structure of obligate freshwater species in Western Queensland river systems. It has indicated that contemporary movements of freshwater species generally are extremely limited across the region, whereas episodic dispersal across catchment boundaries was possible during the Pleistocene, due to different patterns of river connectivity.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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33

Howell, Timothy David. "Fish Responses to the Introduction of Structural Woody Habitat in Two Coastal Rivers in New South Wales, Australia." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/365396.

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The declining condition of river systems associated with rapid development of human societies has lead to substantial reductions in the distributions and populations of many freshwater fish. One consequence of the general decline in river condition has been the loss of in-stream Structural Woody Habitat (SWH). Structural woody habitat is now widely recognised as an important component of stream ecosystems, particularly as fish habitat. As a result, there has been an increase in the number of rehabilitation programs that introduce SWH into rivers globally, and in Australia. However, most rehabilitation works remain unmonitored or inadequately monitored and hence their effectiveness remains largely untested and/or poorly recorded. This thesis assesses fish responses to the introduction of SWH in two coastal rivers of New South Wales, Australia. It is focused on evaluation of the key aspects of experimental design that need to be taken into consideration when planning a monitoring program. The results of this study contribute to a growing literature on the monitoring of fish responses to rehabilitation works using introduced SWH. In 2000 a reach scale experiment was undertaken in the Williams River, NSW, with the introduction of SWH to a test reach compared with a geomorphologically similar control reach. Changes in fish species richness, abundance and assemblage structure were quantified over a period of five years after treatment using a Before-After-Control-Impact-Paired (BACIP) design and analysis. The initial increase in fish species richness observed in the two years following SWH introduction (reported in a previous assessment) appeared to have been sustained three years on (i.e. five years after SWH introduction). This outcome suggests that the increased habitat diversity in the test reach following SWH introduction was sufficient to elicit a detectable and sustained response by fishes over the study period of five years. However, the increased fish abundance noted two years after SWH introduction into the test reach appears to have dissipated over the following three years. Analysis of abundance, excluding a small highly abundant species, Retropinna semoni (Australian smelt), suggested that the initial increase in the test reach was due solely to this species. The most plausible explanation for the decrease in fish abundance after the first two years of the experiment was the decrease in available SWH over the study period due to burial by substrate mobilized during high flow events. The Williams River study is representative of the few rehabilitation projects that attempt to monitor fish responses to SWH introduction and, as such, provided the opportunity to examine inadequacies in experimental design and data analysis. Specifically, the Williams River experimental design suffered from: unbalanced sampling effort between the test and control reaches, irregular sampling, a lack of spatial and temporal replication, and potential spatial autocorrelation. The early success reported for the reach scale experimental introduction of SWH in the Williams River motivated the scaling up of rehabilitation works into a larger river, the Hunter River. Aspects of the Hunter River study that improved upon the Williams River study were: increased replication of treatments and controls that were similar at the start of the experiment, increased temporal replication, balanced sampling effort across all sites, systematic temporal sampling, and an effort to measure the potential for spatial autocorrelation. Fish population responses at the meso-habitat scale (i.e. in riffles and pools) were tested using a Multiple-Before-After-Control-Impact (MBACI) experimental and analytical design. The introduction of SWH into riffles and pools in the Hunter River did not elicit a strong response from fish populations at the meso-habitat scale. In the riffle experiment, the introduction of SWH (deflector jams) appeared to create areas of slack water habitat which were utilised by one native fish species (R. semoni) and one exotic species (Gambusia holbrooki - mosquito fish). No increase in fish species richness or abundance following SWH introduction in treatment pools was detected by the MBACI analysis. The most likely explanation for the lack of response to SWH in Hunter River pools is that the volume of wood introduced was very low (approximately 90% less) relative to natural wood levels in this and other Australian rivers, and therefore insufficient to elicit a measurable response from the fish assemblage at the pool scale...
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment
Science, Environment, Engineering and Technology
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34

Tashev, Azamat. "Understanding Ecosystem Services through Organizational Analysis: Application to the Truckee-Carson River System." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1515072255449453.

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35

Hollis, Lucy. "Cretaceous porphyry magmatic-hydrothermal systems in the Tchaikazan River area, southwest B.C." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/15291.

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The Hub, Charlie and Northwest Copper are spatially related mineral showings (Cu ± Mo) located in the Tchaikazan River area of southwest British Columbia. The Tchaikazan River area is located on the boundary between the Intermontane Belt and southeast Coast Belt (SECB). Evidence of magmatic-hydrothermal alteration is preserved throughout the study area. Multiple episodes of magmatic-hydrothermal activity are associated with these three centres of porphyry-style mineralization. The Hub diorite is the oldest dated pluton in the area, with a U-Pb zircon emplacement age of 81.19 ± 0.78 Ma. ZFT/AFT data suggests an emplacement depth of> 4km for the Hub diorite. The Hub diorite is crosscut by a biotite ± magnetite (± quartz) matrix/cemented hydrothermal breccia. A feldspar hornblende dyke crosscuts both the diorite and hydrothermal breccia and gives a U-Pb zircon age of 79.9 ± 1.5 Ma. Copper, molybdenite ± galena occurs in quartz veining and cement to the hydrothermal breccia. ZFT/U-Pb and Ar-Ar ages for the Hub diorite are within error of each other. AFT data suggests an average erosion rate of 40 m/myr for intrusive rocks in the Taseko Lakes area. Field relationships, geophysical anomalies, geochronology, and stable isotope data suggest that there are three centres for magmatic-hydrothermal activity in the Tchaikazan River area: The Hub, Northwest Copper pluton, and Ravioli Ridge. The area displays evidence for multiple, temporally-distinct intrusive, alteration and mineralizing events.

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36

Gray, Andrew. "Sediment transport and sedimentation dynamics in small mountainous, dry-summer river systems." Thesis, University of California, Davis, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3637835.

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Fluvial suspended sediment is a master variable affecting a wide range of fluvial and coastal environmental processes, and dominating the terrestrial mass flux to the oceans. Although it has long been recognized that relationships between suspended sediment concentration and discharge are not stationary in small, mountainous rivers over time scales from hours to decades, most studies continue to assume stationarity. This collection of studies directly addresses the issue of non-stationarity in the suspended sediment –discharge relationship of the Salinas River, central California, and examines the progression of abandoned channel fill sequences in the Eel River Estuary of northern California.

Preceding these studies is a methodological analysis of the pretreatment of fluvial and marsh sediments for particle size analysis. Pretreatment of sediment with hydrogen peroxide to remove organic constituents and aid deflocculation is a common component of particle size analyses of terrestrial and marine sediments. The first chapter presents the quantitatively determined effect of a range of treatment levels on particle size distribution among four sediment types representing a range of mineral/organic particle size distributions, organic content and particle characterization (charcoal or detrital plant material).

The following three chapters examine the effects of antecedent basin conditions on the suspended sediment – discharge relationship in the Salinas River. In chapter two, forty-five years of suspended sediment data from the lower Salinas and 80 years of hydrologic data were used to construct hydrologic descriptors of basin preconditioning and test the effects of these preconditions on suspended sediment behavior. Fine (diameter (D) < 63 μm) and sand sized (D > 63 μm) sediment were found to respond differently to antecedent hydrologic conditions. Fine sediment was most sensitive to flushing flows of moderate discharge (10 – 20x mean discharge (Q_mean) that led to lower subsequent fine sediment concentrations, while sand concentrations were generally decreased by periods of drought and longer elapsed time since a wide range of discharges acting as maintenance flows.

Chapter three examines the interannual to decadal scale persistence of suspended sediment – discharge relationship states in the lower Salinas River, assesses the role of antecedent hydrologic conditions in controlling these patterns, and addresses their relationship to El Niño Southern Oscillation (ENSO) climatic states. The decadal scale variability in suspended sediment behavior was influenced by interannual to decadal scale fluctuations in hydrologic characteristics, including: elapsed time since small (∼ 0.1x Qmean), and moderate (∼ 10x Qmean) threshold discharge values, the number of preceding days that low/no flow occurred, and annual water yield. El Niño climatic activity was found to have little effect on decadal-scale fluctuations in the fine suspended sediment – discharge relationship due to low or no effect on the frequency of moderate to low discharge magnitudes, annual precipitation, and water yield. However, sand concentrations generally increased in El Niño years due to the increased frequency of moderate to high magnitude discharge events, which generally increase sand supply.

Chapter four brings to bear the decadal scale persistence of suspended sediment - discharge behavior, the effects of antecedent hydrologic conditions, and ENSO influences on the estimation of inter-decadal scale sediment flux from the Salinas River. The longer sampling records employed in this study and incorporation of decadal scale behavior or antecedent hydrologic conditions resulted in average annual load estimates of 2.1 or 2.4 Mt, in comparison to earlier estimates of ∼ 3.3 Mt by previous researchers. El Niño years dominated the sediment budget by producing on average ten times more sediment than non-El Niño years.

Chapter five proposes a modification of the current generic model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. This work was based on evidence from two consecutive abandoned channel fill sequences in Ropers Slough of the lower Eel River Estuary. Planform geomorphic characteristics derived from these images were used in conjunction with sub-cm resolution stratigraphic analyses to describe the depositional environment processes and their resultant sedimentary deposits. The abandoned channel fill sequences appeared to differ due to the topographic steering of bed sediment transport and deposition previously identified in rivers experiencing only unidirectional flow, while also expressing the seasonal dichotomy of fluvial and tidal deposits.

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37

Hill, Gemma. "Investigating wastewater treatment plant impact on antibiotic resistance within UK river systems." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/88822/.

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Antimicrobial resistance (AMR) presents one of the most important threats to human health of the 21st century. The recent report on AMR predicted that by 2050 10 million deaths a year will be directly attributable to AMR bacterial infections. The dissemination of antibiotic resistance genes (ARG) in to the environment has previously been highlighted as an important route of transmission and was investigated in the current study. Wastewater treatment plants (WWTP) have been highlighted to contribute to ARG pollution of rivers focusing on effluent impact on receiving water bodies. In this study the aim was to further investigate the effects of WWTP effluent on the receiving river, but also investigate the release of raw sewage resulting from combined sewer overflow (CSO) events on the receiving river. This study found that sediment samples carried a higher abundance of all ARG and therefore present a greater risk compared to water and that CSO spills are important in the spread of ARG likely contributing more substantially to the environmental spread of resistance than continuous release of treated wastewater. In addition, the present study aimed to investigate the genetic potential of viable, potentially pathogenic Escherichia coli isolates from the river sediment to determine whether these human opportunistic pathogens carried the genetic capacity to spread resistance and cause disease. E. coli strains were shown to carry extensive resistance to many clinically relevant antibiotics, metals and biocides as well as carrying vast virulence-associated genes. This study identified ST940 as an important sequence type (ST) in the dissemination of the ESBL blaCTX-M-15 gene and suggests further work to investigate the importance of this ST type in the transmission of this clinically important ARG. The work presented here supports previous studies demonstrating extensive environmental ARG dissemination in rivers as a direct result of WWTP impacts and further highlights rivers as an important reservoir of ARG and antibiotic resistant bacteria (ARB). The discovery of clinically important viable E. coli isolates in sediment suggests more rigorous methods of wastewater treatment, specifically a reduction in the number of CSO release events, must be employed if further dissemination of ARB is to be prevented.

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38

Long, Nguyen Tien. "Sustainabilty assessment of vegetable cultivation systems in the Red River Delta, Vietnam." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2013. http://dx.doi.org/10.18452/16763.

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Zur Einschätzungen und Bewertung der Nachhaltigkeit der gegenwärtigen Gemüseproduktion im Roten-Fluss-Delta, Vietnam, erfolgten empirische Untersuchungen zur Ermittlung und Bewertung eines Nachhaltigkeitsindex unter Nutzung verschiedener Lösungsansätze. Die Analysen und Einschätzungen wurden aus ökologischer ökonomischer und sozialer Sicht vorgenommen. Die erfassten Daten wurden unter Nutzung von zwei Methoden ausgewertet, der Mehr-Kriterien-Bewertungsmethode Analytic Hierarchy Process (AHP) und der Fuzzy Bewertungsmethode. In Workshops wurden mit den Farmern Präferenzen als Element der AHP, zu den Kriterien die Ausdruck der Nachhaltigkeit sind, erarbeitet. Es wurde herausgearbeitet, dass im ländlichen Raum, die Gemüseproduktion nachhaltig ist, im Peri-urbanen Raum wurde eine geringe Nachhaltigkeit ermittelt und im urbanen Raum keine Nachhaltigkeit. Im Ergebnis der Forschungsarbeit wurde herausgearbeitet, dass für einen nachhaltigen Gemüse-Anbau im Roten-Fluss-Delta, die Farmer ihr Kontrollsystem und System der Nachverfolgbarkeit verbessern müssen. Gleichermaßen ist es erforderlich die sozialen Bedingungen so zu gestalten, das die Prinzipien der‚ Guten Landwirtschaftlichen Praxis‘ greifen. Im Rahmen der Forschungsarbeit konnte gleichfalls eine Bewertung der Nachhaltigkeit unter Nutzung der Fuzzy Methode erfolgreich eingesetzt werden. Diese Ergebnisse sind geeignet, sowohl den Farmern, als auch den politischen Entscheidungsträgern, die geeigneten Werkzeuge für die Entwicklung einer nachhaltigen Gemüse Kultivierung in der Zukunft zu geben.
This study is empirical research by applying different sustainability assessment approaches to evaluate and to compare the sustainability index of the existing vegetable cultivation systems in the Red River Delta - the largest vegetable production land area of Vietnam in terms of environment, economic and social dimensions. In addition, this study also incorporated farmers'' perceptions as well as their preferences into the weight of criteria by using Analytic Hierarchy Process (AHP) in multi-criteria evaluation method, and rules formed in fuzzy evaluation method. The results from the sustainability assessment for the vegetable cultivation systems show that in the rural area, the sustainability are acceptable whereas in the peri-urban area are only conditionally acceptable, and in the urban area are not sustainable. The results from this study indicate that, to achieve sustainable vegetable cultivation systems in the Red River Delta in Vietnam, the farmers need improved internal controls and tracing systems as well as strict social control in order to implement good agricultural practices guidelines. This study result also shows that the sustainability assessment by fuzzy evaluation approach appears to be well suited to provide quantitative answers pertaining to sustainability that can help policy maker in choosing the tool for sustainability assessment in the future.

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39

Hardbattle, Carol. "Slope-channel connectivity for fine sediment transport in river systems : a national perspective." Thesis, University of Exeter, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410810.

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40

Müller, Maximilian Eckhard [Verfasser]. "Organic Micropollutants in Small River Systems – Occurrence, Fate and Effects / Maximilian Eckhard Müller." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1223451631/34.

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41

Yanagisawa, Masayuki. "Agroecological evaluation of the intensified cropping systems in the Red River Delta,Vietnam." Kyoto University, 2000. http://hdl.handle.net/2433/78117.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第8632号
農博第1159号
新制||農||814(附属図書館)
学位論文||H12||N3477(農学部図書室)
UT51-2000-R38
京都大学大学院農学研究科熱帯農学専攻
(主査)教授櫻谷哲夫, 教授天野高久, 教授小﨑隆
学位規則第4条第1項該当

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42

Saunders, James Edward. "Measuring and understanding biogenic influences upon cohesive sediment stability in intertidal systems." Thesis, St Andrews, 2008. http://hdl.handle.net/10023/868.

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43

Neurath, Robert Carl. "Comparative Baseflow Hydrochemistry of Various Septic System Density Groups within the Yellow River Watershed, Gwinnett County, Georgia." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/geosciences_theses/9.

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Baseflow water chemistry between different septic system density groups was analyzed to understand how septic system usage impacts the water quality of the Yellow River Watershed located in Gwinnett County, Georgia. Seventy water samples were collected at baseflow conditions in the summer of 2006. The samples were analyzed for the abundance and distribution of chlorides, sulfates, nitrates, and specific conductance. Geographic Information Systems were used to determine sample collection sites, assign samples into density groups, and spatially analyze and display the results. Statistical methods were used to compare the results of each density group with all others,and to find any correlation of the anions with respect to specific conductance. Regression coefficient values between nitrate and specific conductance in all groups average 0.77 and the elevated nitrate concentrations in group four suggest a limited relationship between septic system density and baseflow water quality.

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44

Denson, Robyn L. "A conceptual methodology for studying the geoarchaeology of fluvial systems : with case studies from the Oklawaha River (Florida) and the River Earn (Scotland)." Thesis, University of St Andrews, 1995. http://hdl.handle.net/10023/15148.

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This thesis explores a conceptual methodology for studying archaeological sites in fluvial settings. The methodology stems from geoarchaeology, an approach to the past that focuses upon the geomorphic context of artifacts or the application of geological principles and techniques to the solution of archaeological problems. The paper will examine its application to fluvial systems in two different geomorphic environments, the Oklawaha River in Florida and the Earn River Valley in Scotland. In these different environmental settings, the geoarchaeological approach makes use of different kinds of evidence available to it. Survey in submerged and eroding river margins offers additional information on site distribution and density within the landscape that can go unnoticed by traditional terrestrial surveys. Through conceptualization and application of the methodology that has developed from these studies, the arbitrary land/water interface can effectively be erased from research areas and rivers can begin to be viewed not as permanent and non-moving barriers, but as significant and dynamic components of the archaeological landscape.

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45

Sonnenberg, Rob. "Development of aquatic communities in high-altitude mine pit lake systems of west-central Alberta." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Geography, 2011, 2011. http://hdl.handle.net/10133/3106.

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Reclamation on the Cardinal River and Gregg River coal mines includes the construction of mine pit lakes connected to stream environments. Key physical, chemical and biological parameters of these “truck and shovel” lakes and their streams were investigated, and hypotheses regarding ecosystems and populations were tested. Findings include: Sphinx Lake and Pit Lake CD exhibit meromictic (partial-mixing) tendencies, but still function in a similar fashion to shallower, natural sub-alpine lakes. Elevated selenium concentrations as high as 16 ug/g (dry weight) were recorded in Rainbow trout (Oncorhynchus mykiss) eggs taken from gravid Sphinx Lake and Pit Lake CD fish. Potential detrimental effects associated with the bioaccumulation of selenium on fish reproduction were not observed. Stream water temperatures downstream of Sphinx Lake and Pit Lake CD were significantly warmer than in inlet streams and streams without pit lakes. Streambed concretions caused by calcite precipitation were documented and found to affect portions of the upper Gregg River basin. Remediation of this concretion is important for sustainability of trout populations. Aquatic communities including fish, invertebrates, zooplankton and aquatic plants are present in these pit lake systems. Athabasca Rainbow trout populations are self-propagating (spawning at the outlets) with higher densities downstream than there were prior to lake reclamation. The development of sub-alpine mine-pit lakes connected to the stream environment appears to be an appropriate and beneficial reclamation technique in this area.
xvi, 224 leaves : col. ill., map ; 28 cm

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46

Winterbottom, Sandra J. "An analysis of channel change on the Rivers Tay and Tummel, Scotland, using GIS and remote sensing techniques." Thesis, University of Stirling, 1995. http://hdl.handle.net/1893/2178.

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This thesis examines historical river channel change on a 12km study reach of the Rivers Tay and Tummel Scotland via the development of GIS and remote sensing techniques. Firstly, historical maps were combined using GIS rectification techniques in order to examine channel changes over the period 1755 to 1975. Secondly, also using GIS methodology, channel planforms as depicted in a series of aerial photographs were overlain to study recent channel change (1971 to 1994) including that caused by two major flood events. The study formed part of wider investigations into the hydrology and geomorphology of the River Tay, following the 1990 and 1993 flood events commissioned by organisations involved with management of the river. The study reach in 1863 and 1899 was shown to have alternating, highly divided sections with multiple mid-channel islands, and stable single-thread sections although, overall, the channel was less braided than depicted on 18th century maps. By 1975, the multi-channel sections had changed to a predominantly single-thread character and it is proposed that this had occurred in response to flood embankment construction and bank protection leading to channel narrowing and incision. This has wider implications for the management of the River Tay as channel instability supports diverse natural habitats with high conservation value. Once recent river planform changes on the study reach had been identified, stable and unstable reaches were defined allowing the determination of the degree and nature of instability using GIS methodology which included quantification of active channel widths and gravel area, braiding indices, sinuosity and channel occupancy indices. A number of unstable reaches were also studied in the field to examine the processes responsible for river bank erosion. In addition, the effect of in-channel morphology on river planform changes was examined by applying image analysis to bands 3, 5, 6 and 8 of airborne multi-spectral imagery (Daedalus ATM) to map channel bathymetry. The results showed that changes in channel planform and position occurred almost entirely in response to extreme flood events and that areas of greatest channel change were in zones of historical instability resulting from the presence of less cohesive sediments along the courses of former river channels. A meander-like alternation of pool-riffle sequences controlled the local distribution of bank erosion along most of these reaches by deflecting thalwegs against outer banks. The information derived from the study was used to construct an erosion hazard map. Using raster-based GIS techniques, these data were combined with measurements of distance from river channel and flood return periods, to create a model which enabled spatial mapping of river bank erosion probabilities. These probabilities were then mapped for hypothetical floods of 5, 10 and 25 year recurrence interval.

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Diop, Mariane. "The influence of weather systems on satellite rainfall estimation with application to river flow." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397102.

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Sinawi, Ghida. "Aggregation of suspended sediment in fluvial systems : a case study of the River Exe." Thesis, University of Exeter, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307289.

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Cao, Yong. "Spatial and temporal changes of macroinvertebrate community structure in two UK lowland river systems." Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283356.

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Duffy, B. "Phase transfer processes affecting the chemistry of iron and manganese in river-estuary systems." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356766.

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Dissertations / Theses on the topic 'River systems'

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