Dissertations / Theses on the topic 'Flood irrigation'

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1

Ottman, M. J., and J. E. Watson. "Nitrate Leaching Potential from a Single Border-Flood Irrigation." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/201383.

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Groundwater contamination by nitrate and other chemicals is a public concern and has subjected agriculture to scrutiny. Field studies were conducted at the Maricopa and Marana Agricultural Centers in 1989 to 1990 to document nitrate leaching potential with border flood irrigation. Calcium nitrate fertilizer was applied at various rates along with potassium bromide, which serves as an additional indicator of nitrate movement. Approximately 8.55 inches of irrigation water was applied at the Maricopa site on a sandy loam soil and 4.0 inches of irrigation water was applied at the Marana site on a clay loam soil. At the Maricopa site, only 64% of the nitrate could be accounted for in the top 6.7 ft. while most of the nitrate was found in the top 4 to 5 ft. at Marana. The water and nitrate moved 3 to 4 times deeper than predicted in the absence of preferential flow.
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2

Thompson, Paul M. "The impact of flood control on rural development in Bangladesh : post evaluation of the Chandpur Project." Thesis, Middlesex University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254599.

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In Bangladesh flood mitigation strategies have concentrated on embankments. However, due to a perceived lack of success with this strategy and high returns to irrigation development, the emphasis in water management switched towards small scale irrigation. Serious floods in 1987 and 1988 have renewed interest in flood mitigation. However, there is a lack of detailed evidence on the impacts of embankments. This study provides just such evidence. The study comprises a detailed post-evaluation of a major flood control, drainage and irrigation project, the Chandpur Irrigation Project. The results show that the project has been successful in reducing normal monsoon water levels, with consequent changes in cropping patterns to higher yielding varieties. However, a with-without comparison revealed that expected yields (allowing for risks of flooding and drainage problems) were less than predicted due to drainage problems within the project, whereas non-project expected yields are as predicted. Hence agricultural output has increased substantially, but output and its value are less than anticipated. Household incomes in the project are 25&37 higher (on average) than in control areas, but this is because larger landowners have gained from greater returns to agriculture (for example, from preferential access to irrigation), and diversifying into other occupations. Some households have gained by selling land and obtaining salaried jobs elsewhere or by becoming traders. By comparison small landowners may be slightly less prone to losses in flood years but have not moved into surplus. Landless labourers have similar incomes inside and outside the project; real wages are unchanged, and increased work has not compensated for population growth. Inside the project changes in landholding category have been fewer than outside. Open water fish populations have been reduced by the embankment, particularly affecting poor households. However, fish cultivation has expanded more than in flood prone areas, benefiting pond owners and enabling professional fishermen to maintain their incomes (at the cost of greater dependence on larger landowners). Improved methods of post-evaluation (which have implications for appraisal of new projects) are developed to incorporate flood risks and consequent yield reductions and non-agricultural damages, and to standardise economic valuation. Applying these methods revealed that the Chandpur Project has been, despite an uneven distribution of benefits, relatively successful (an economic rate of return of at least 5%). Although there are some project specific reasons for this success, this project has suffered many problems typical of embankment in Bangladesh. Hence embankments are potentially important for the future economic development of Bangladesh - by reducing damage and disruption and increasing agricultural output. The study concludes with recommendations for improved flood plain planning in Bangladesh, using detailed flood loss data and improved appraisal methods, to ensure that choice of flood mitigation strategies and investments are rational, and that all public investments take flood risks into account.
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3

Halls, Ashley Stewart. "An assessment of the impact of hydraulic engineering on floodplain fisheries and species assemblages in Bangladesh." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/7704.

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4

Summerford, Sarah Elizabeth. "Characterization of soil/vegetation on flood irrigated hayfields in Grand Teton National Park, Wyoming: a predictive evaluation tool for agricultural wetlands." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/summerford/SummerfordS0509.pdf.

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The Elk Ranch hayfield in Grand Teton National Park (GTNP) has been historically flood-irrigated since the early 20th Century. The park service is now considering closing irrigation to restore native plant communities and enhance Spread Creek fisheries and will need information on the extent of irrigation-created wetlands and how irrigation cessation would change the vegetative component of the ranch. The main objective of this study was to assess the relation between soil and vegetation characteristics of wetland community types at the ranch and to determine if any of the relationships could be used to differentiate between naturally occurring and irrigation created wetlands. Vegetation data were collected from transects centered on a soil pit at 28 randomly located sample points throughout the hayfield. Twenty-six of the 28 sample plots were classified as wetland based on criteria listed by the US Fish and Wildlife Service. Bray-Curtis dissimilarity and nonmetric multi-dimensional scaling were used to analyze percent foliar cover, wetland index value (WIV), soil texture, percent organic matter, redox contrast and abundance, and depth to groundwater and soil saturation for each of the sampled points. The WIV and redox contrast had the greatest dissimilarity (D2), 0.90, and 0.71 respectively across the hayfield. The other measured characteristics had D2 values ranging from 0.23 to 0.49 and were strongly correlated with the WIV and redox contrast measures. However, inclusion of these measures contributed little to the differences already identified. Categorical organization of WIV and redox measures indicated that naturally occurring wetlands could be differentiated from wetlands created by flood irrigation in former upland vegetation communities. Combining wetland index value and soil redox contrast suggests park managers could identify wetland community types likely to remain or transition following cessation of flood irrigation at the Elk Ranch. Additional testing at other GTNP sites will be necessary to test the broad application of this approach and refine the assessment categories.
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5

Jiang, Shuang. "Bacterial leaching from dairy shed effluent applied to a fine sandy loam under flood and spray irrigations." Lincoln University, 2008. http://hdl.handle.net/10182/668.

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Land application of wastes has become increasingly popular, to promote nutrient recycling and environmental protection, with soil functioning as a partial barrier between wastes and groundwater. Dairy shed effluent (DSE), may contain a wide variety of pathogenic micro-organisms, including bacteria (e.g. Salmonella paratyphyi, Escherichia coli. and Campylobacter), protozoa and viruses. Groundwater pathogen contamination resulting from land-applied DSE is drawing more attention with the intensified development of the dairy farm industry in New Zealand. The purpose of this research was to investigate the fate and transport of bacterial indicator-faecal coliform (FC) from land-applied DSE under different irrigation practices via field lysimeter studies, using two water irrigation methods (flood and sprinkler) with contrasting application rates, through the 2005-2006 irrigation season. It was aimed at better understanding, quantifying and modelling of the processes that govern the removal of microbes in intact soil columns, bridging the gap between previous theoretical research and general farm practices, specifically for Templeton soil. This study involved different approaches (leaching experiments, infiltrometer measurements and a dye infiltration study) to understand the processes of transient water flow and bacterial transport; and to extrapolate the relationships between bacterial transport and soil properties (like soil structure, texture), and soil physical status (soil water potential ψ and volumetric water content θ). Factors controlling FC transport are discussed. A contaminant transport model, HYDRUS-1D, was applied to simulate microbial transport through soil on the basis of measured datasets. This study was carried out at Lincoln University’s Centre for Soil and Environmental Quality (CSEQ) lysimeter site. Six lysimeters were employed in two trials. Each trial involved application of DSE, followed by a water irrigation sequence applied in a flux-controlled method. The soil columns were taken from the site of the new Lincoln University Dairy Farm, Lincoln, Canterbury. The soil type is Templeton fine sandy loam (Udic-Ustochrept, coarse loamy, mixed, mesic). Vertical profiles (at four depths) of θ and ψ were measured during leaching experiments. The leaching experiments directly measured concentrations of chemical tracer (Br⁻ or Cl⁻) and FC in drainage. Results showed that bacteria could readily penetrate through 700 mm deep soil columns, when facilitated by water flow. In the first (summer) trial, FC in leachate as high as 1.4×10⁶ cfu 100 mL⁻¹ (similar to the DSE concentration), was detected in one lysimeter that had a higher clay content in the topsoil, immediately after DSE application, and before any water irrigation. This indicates that DSE flowed through preferential flow paths without significant treatment or reduction in concentrations. The highest post-irrigation concentration was 3.4×10³ cfu 100 mL⁻¹ under flood irrigation. Flood irrigation resulted in more bacteria and Br⁻ leaching than spray irrigation. In both trials (summer and autumn) results showed significant differences between irrigation treatments in lysimeters sharing similar drainage class (moderate or moderately rapid). Leaching bacterial concentration was positively correlated with both θ and ψ, and sometimes drainage rate. Greater bacterial leaching was found in the one lysimeter with rapid whole-column effective hydraulic conductivity, Keff, for both flood and spray treatments. Occasionally, the effect of Keff on water movement and bacterial transport overrode the effect of irrigation. The ‘seasonal condition’ of the soil (including variation in initial water content) also influenced bacterial leaching, with less risk of leaching in autumn than in summer. A tension infiltrometer experiment measured hydraulic conductivity of the lysimeters at zero and 40 mm suction. The results showed in most cases a significant correlation between the proportion of bacteria leached and the flow contribution of the macropores. The higher the Ksat, the greater the amount of drainage and bacterial leaching obtained. This research also found that this technique may exclude the activity of some continuous macropores (e.g., cracks) due to the difference of initial wetness which could substantially change the conductivity and result in more serious bacterial leaching in this Templeton soil. A dye infiltration study showed there was great variability in water flow patterns, and most of the flow reaching deeper than 50 cm resulted from macropores, mainly visible cracks. The transient water flow and transport of tracer (Br⁻) and FC were modelled using the HYDRUS-1D software package. The uniform flow van Genuchten model, and the dual-porosity model were used for water flow and the mobile-immobile (MIM) model was used for tracer and FC transport. The hydraulic and solute parameters were optimized during simulation, on the basis of measured datasets from the leaching experiments. There was evidence supporting the presence of macropores, based on the water flow in the post-DSE application stage. The optimised saturated water content (θs) decreased during the post-application process, which could be explained in terms of macropore flow enhanced by irrigation. Moreover, bacterial simulation showed discrepancies in all cases of uniform flow simulations at the very initial stage, indicating that non-equilibrium processes were dominant during those short periods, and suggesting that there were strong dynamic processes involving structure change and subsequently flow paths. It is recommended that management strategies to reduce FC contamination following application of DSE in these soils must aim to decrease preferential flow by adjusting irrigation schemes. Attention needs to be given to a) decreasing irrigation rates at the beginning of each irrigation; b) increasing the number of irrigations, by reducing at the same time the amount of water applied and the irrigation rate at each irrigation; c) applying spray irrigation rather than flood irrigation.
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6

Smith, S. Andrew Enticknap. "Water first." Connect to full text, 2002. http://thesis.anu.edu.au/public/adt-ANU20050314.135921/index.html.

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7

Ziyadi, Mohamed. "Vivre dans les montagnes arides ou sub-arides : l'aménagement des pentes dans l'Anti-Atlas central et occidental (Maroc)." Thesis, Nancy 2, 2011. http://www.theses.fr/2011NAN21028/document.

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Les conditions de vie offertes par la montagne anti-atlasique aux populations ne sont guère favorables au travail de la terre : la pluviosité est très irrégulière et insuffisante, le sol est squelettique et caillouteux car il se développe à partir d'un substrat géologique ancien et sur des pentes fortes. Pour pallier ces conditions hostiles, la société montagnarde de l'Anti-Atlas marocain s'est efforcée depuis des siècles, peut-être même depuis des millénaires, d'aménager pratiquement toutes les pentes pour y fixer la terre arable et surtout pour y récupérer tout le ruissellement pluvial afin d'en imbiber les terres. Ces aménagements sont aujourd'hui parfois fossilisés par l'abandon de l'activité agricole et sont menacés de ruine ou de disparition. Cette situation est évidente dans toutes les contrées anti-atlasiques que nous avons parcourues. C'est une oeuvre et un savoir-faire paysans qui sont donc en danger. Il est important de les étudier alors que ces artefacts sont encore partiellement fonctionnels et qu'ils peuvent encore participer à l'enrichissement du potentiel culturel de cette montagne méridionale déjà si riche, par ailleurs, de paysages et de vestiges architecturaux de toute sorte
The living conditions of the population in the Anti-Atlas Mountains are not ideal for agriculture: rains are very irregular and insufficient; the soil is skeletal and stony, as it develops from an old geological substratum and on steep slopes. To make up for those hostile conditions, for centuries and perhaps for millennia, the mountain society of the Moroccan Anti-Atlas has endeavoured to manage the slopes so as to preserve arable land and especially to capture rainfall runoff, so as to imbibe the land with it. Nowadays, those structures are sometimes fossilized and threatened with disrepair and destruction now that agricultural activities have come to an end. This situation is striking in all the Anti-Atlas areas I have travelled through. The work and the skills of local farmers are therefore in danger of being lost. It is essential to study those artifacts while they are still partly functional, as they can still enrich the cultural potential of this southern mountainous area, already rich of its many landscapes and architectural vestiges
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8

Müller, Isabell [Verfasser], Hermann F. [Akademischer Betreuer] [Gutachter] Jungkunst, and Jens [Akademischer Betreuer] Schirmel. "The influence of traditional flood irrigation on biodiversity, plant Functional composition and plant nutrient availability in Central European grassland / Isabell Müller ; Gutachter: Hermann F. Jungkunst ; Hermann F. Jungkunst, Jens Schirmel." Koblenz, 2017. http://d-nb.info/1138981672/34.

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9

Müller, Isabell Bianca [Verfasser], Hermann F. [Akademischer Betreuer] [Gutachter] Jungkunst, and Jens [Akademischer Betreuer] Schirmel. "The influence of traditional flood irrigation on biodiversity, plant Functional composition and plant nutrient availability in Central European grassland / Isabell Müller ; Gutachter: Hermann F. Jungkunst ; Hermann F. Jungkunst, Jens Schirmel." Koblenz, 2017. http://d-nb.info/1138981672/34.

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10

Corrêa, Henrique Cunha. "ADEQUAÇÃO DA DEMANDA HÍDRICA E DA POTÊNCIA INSTALADA EM SISTEMAS DE RECALQUE PARA O ARROZ NA DEPRESSÃO CENTRAL DO RIO GRANDE DO SUL." Universidade Federal de Santa Maria, 2007. http://repositorio.ufsm.br/handle/1/7632.

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The rice culture for Rio Grande do Sul economy is of great relevance. Annually, around one million of hectares are planted. As it is a culture irrigated by a continuum flood, the supply of the high hydric demand is done in 70% of the area through pumping station, representing a significant portion of the production costs. Associate with this fact, there is a necessity in reducing water and energy consumption, object of several official and private actions undertaken in the latest years with the object of preserving the sources, reducing costs and contouring conflicts in the water access. The objective of this work was to find an easily and quickly way of planning, trying to help the extensions of the pumping station to rice irrigation. Real known data were used related to the ground-plant-climate system of the Central Depression rice culture region, doing a calculation based in the simplified hydric balance adapted to the rice farming system. Instantaneous hydric demands were calculated for the initial flood and for the maintenance of the flood until the end of the irrigation cicle. To reduce either outflows or installed powers was adopted a division of the total areas established in the simulation (between 10 and 190 ha), and after was done a temporal stagger of the sowing and the irrigation process. A reduction of 64% in the outflow of the initial flow was attained and 63% in the installed electrical powers of the pumping station, when compared to the simultaneous flow process of the farming total areas. When it was used the regression analysis, were got equations for outflows adjustment and required power in operation of total areas for estimations in the intervals of the adopted areas in the work. The resource makes possible the previous planning of farmings relating to the instantaneous demand for initial flow and support supply, as well as in relation to the electrical powers, observing pumping stations in installations in parallel (two or more pump motor system) sets. Another possible application refers to the procedures of elaborating Basin Administrative Committees and corresponding processes of warranting right of water use, in order to offer basic and trustful information to establish maximum cultivable areas because of the minimum availabilities established regionally to the activity.
É incontestável a relevância da cultura do arroz para a economia do Rio Grande do Sul. São plantados anualmente em torno de um milhão de hectares, os quais são irrigados por inundação contínua, exigindo elevada demanda hídrica. O suprimento hídrico do cultivo é atendida em 70% da área através de sistemas de recalque (bombeamento), representando uma parcela apreciável do custo de produção e compreendendo, entre custos diretos e indiretos, 27% do custo total. Evidencia-se assim a necessidade de redução no consumo de água e energia, objeto de várias ações oficiais e privadas empreendidas nos últimos anos com vistas a preservar os mananciais, reduzir custos e contornar conflitos no acesso à água. O foco do presente trabalho voltou-se para a busca de uma ferramenta de planejamento de fácil e ágil aplicação, visando subsidiar os dimensionamentos de sistemas de recalque para a irrigação do arroz. Partiu-se de dados reais típicos relativos ao sistema solo-planta-clima da Região Orizícola da Depressão Central, estabelecendo-se um procedimento de cálculo baseado no balanço hídrico simplificado adaptado ao sistema lavoura de arroz . Foram calculadas as demandas hídricas instantâneas para as fases de inundação inicial e para a manutenção da inundação até o final do ciclo de irrigação. Objetivando a redução tanto das vazões quanto das potências instaladas, foi adotado um fracionamento das áreas totais estabelecidas na simulação (entre 10 e 190ha, em incrementos de 20ha), com conseqüente escalonamento temporal do processo de irrigação. Atingiu-se dessa forma uma redução de até 64% na vazão de inundação inicial e de até 63% na potência instalada elétrica dos sistemas de recalque, quando comparados a processo de inundação simultânea das áreas totais das lavouras. Aplicando análise de regressão foram ajustadas equações que permitem estimar vazões e potências requeridas em função de áreas totais de lavoura no intervalo de áreas da simulação. Este recurso possibilita o planejamento de lavouras no tocante às vazões mínimas requeridas para inundação inicial e para o suprimento de manutenção, bem como em relação ao pré-dimensionamento das potências elétricas mínimas correspondentes, contemplando sistemas de recalque na modalidade de instalações em paralelo (dois ou mais conjuntos motor-bomba). Foram igualmente calculados os módulos de irrigação (vazões específicas expressas em l.s-1.ha-1) para as fases de inundação inicial e de manutenção. Os resultados obtidos permitem aplicações no planejamento regional (alocação de recursos hídricos), no planejamento de formação de lavouras, na estimativa de volumes totais de demanda, em prédimensionamentos de estações de bombeamento, em ações de re-engenharia de instalações existentes e no processo de outorga de direito de uso da água.
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11

Köpp, Luciana Marini. "INDICES DE DESEMPENHO PARA ESTAÇÕES DE BOMBEAMENTO EM LAVOURAS DE ARROZ IRRIGADO." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/3629.

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The state of Rio Grande do Sul (RS) grown in crop 2013/2014, 1,120,112 ha of rice, making up 46.18% of the cultivated area in Brazil, accounting for 66.21% of national production. The Fronteira Oeste of RS cultivated an area of 333,695 ha and 85.7% of this water pumping stations are used, making the cost of irrigation represents 10.74% of the total cost of production of cereal, one of the most expressive. The efficiency of energy use in the process of irrigation of rice fields linked to this agronomic aspects (definition of cultivars and suitable choice of the area) and engineering (pump of choice with adequate affieciency, adjusted net power engine with the need, compatible coupling with installed capacity, pipe sizing, positioning the pump-motor assembly and use of special parts). The lack of parameters that can define the quality of the design of pumping stations creates uncertainty regarding the proper use of energy in the process. Performance indices are indicators that can be used to establish the quality of pumping stations, with regard to aspects sizing. This work aimed to propose performance indexes and ranks them in order to generate referrals, to be used for evaluation of water pumping stations in irrigated rice fields. We evaluated 160 pumping stations, located on the Western Border of RS, under normal working conditions. For each of them were determined appropriate piping, through total cost minimization analysis (fixed more operational) for a period of 10 years of operation, and checked the possible power savings from the same exchange. Similarly been proposed replacement of equipment (pumps and motors) seeking, among commercially available, those with higher operating efficiency for the working conditions of each season. Were proposed nine performance indices and applied situations initially found in the field and those optimized by the replacement of pipes, pumps and motors. The variability found allowed them to be categorized and then was proposed performance index rating as "excellent", "very good", "good", "bad" and "very bad".
O Estado do Rio Grande do Sul (RS) cultivou, na safra 2013/2014, 1.120.112 ha de arroz irrigado, perfazendo 46,18% da área cultivada com o cereal no Brasil, contribuindo com 66,21% da produção nacional. A região da Fronteira Oeste do RS cultivou uma área de 333.695 ha e, em 85,7% desta são utilizadas estações de bombeamento de água, fazendo com que o custo da irrigação represente 10,74% do custo total de produção deste cereal, sendo um dos mais expressivos. A eficiência do uso de energia no processo de irrigação das lavouras de arroz esta atrelada a aspectos agronômicos (definição das cultivares e escolha adequada da área) e de engenharia (escolha de bomba com rendimento adequado, motor com potência útil ajustada à necessidade, acoplamento compatível com a potência instalada, dimensionamento de tubulação, posicionamento do conjunto bomba-motor e uso de peças especiais). A falta de parâmetros que possam definir a qualidade do dimensionamento das estações de bombeamento gera insegurança em relação ao bom uso da energia no processo. Índices de desempenho são indicadores que podem ser usados para estabelecer a qualidade das estações de bombeamento, no que se refere aos aspectos de dimensionamento. Este trabalho teve como objetivo propor índices de desempenho e classificá-los de forma a gerar referências, a serem usadas para avaliação de estações de bombeamento de água em lavouras de arroz irrigado. Foram avaliadas 160 estações de bombeamento, localizadas na Fronteira Oeste do RS, em condições normais de trabalho. Para cada uma delas foram determinadas as tubulações adequadas, através de análise de minimização de custo total (fixo mais operacional) para um período de 10 anos de operação, e verificada a possível economia de energia gerada pela troca das mesmas. Da mesma forma foram propostas substituição de equipamentos (bombas e motores) buscando, entre os disponíveis comercialmente, aqueles de melhor rendimento operacional para as condições de trabalho de cada estação. Foram propostos nove índices de desempenho e aplicados as situações inicialmente encontradas em campo e aquelas otimizadas pela substituição de tubulações, bombas e motores. A variabilidade encontrada permitiu que os mesmos fossem categorizados e então proposta uma classificação de índices de desempenho como excelente , muito bom , bom , ruim e muito ruim .
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Boberg, Björn, and David Holm. "FEM modeling of concrete gravity dams." Thesis, KTH, Vattendragsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99351.

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13

Brown, Kyle. "The Effects of Past Climate Change and Recent Agricultural Irrigation Recharge on the Sources, Ages, and Quality of Groundwater in the Columbia River Basalt Aquifers, Columbia Basin, Central Washington." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/193418.

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This study uses multiple isotopic (2H, 18O, 13C, 15NNO3, 18ONO3, 87Sr/86Sr) and age tracers (3H, 14C, CFCs), in conjunction with elemental chemistry, to address the following research question: How have present day anthropogenic activities (i.e. surface water irrigation and fertilizer application) and past climatic events (i.e. cataclysmic flooding from glacial Lake Missoula and other modes of discharge from Cordilleran Ice Sheet) impacted the hydrology and geochemistry of the Columbia River Basalt Aquifers (CRBAs) in central Washington? Large-scale irrigated agriculture over the past ~60 years has resulted in the transport of high NO3- irrigation waters moving downward in the oxic CRBAs at rates of several meters per decade with a lack of denitrification. Deeper pristine regional groundwater in the CRBAs is Late Pleistocene in age and likely remnant Cordilleran Ice Sheet-related recharge waters (i.e. glacial Lake Missoula floodwaters).
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Garnier, Philippe. "Le Cher, étude hydrologique." Angers, 1993. http://www.theses.fr/1993ANGE0016.

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Le bassin du Cher est constitué de régions aux caractéristiques hydrologiques tranchées dont les besoins en eau diffèrent fortement. Après avoir analysé un certain nombre d'outils autorisant une première approche du fonctionnement de l'hydrosystème, une prospection systématique des formes de l'écoulement fut menée. Cette seconde partie examine plus particulièrement différentes méthodes de prédétermination des crues, ainsi que les sorties d'étiage. Ces analyses ont permis, en troisième partie, l'établissement de bilans hydrologiques autorisant une vision globale des flux. L'objectif, à ce niveau, était de lire les circulations visibles ou occultes et d'estimer les potentialités de chaque région ou pays. Au bout de compte, il s'agit de disposer d'éléments permettant d'apprécier la pertinence du projet de barrage à Chambonchard. Il s'agit aussi de nourrir une réflexion quant au dimensionnement de l'ouvrage.
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Shannak, Sa'D Abdel-Halim. "Investigating Rainwater Harvesting as a Stormwater Best Management Practice and as a Function of Irrigation Water Use." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8840.

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Stormwater runoff has negative impacts on water resources, human health and environment. In this research the effectiveness of Rain Water Harvesting (RWH) systems is examined as a stormwater Best Management Practice (BMP). Time-based, evapotranspiration-based, and soil moisture-based irrigation scheduling methods in conjunction with RWH and a control site without RWH were simulated to determine the effect of RWH as a BMP on a single-family residence scale. The effects of each irrigation scheduling method on minimizing water runoff leaving the plots and potable water input for irrigation were compared. The scenario that reflects urban development was simulated and compared to other RWH-irrigation scheduling systems by a control treatment without a RWH component. Four soil types (sand, sandy loam, loamy sand, silty clay) and four cistern sizes (208L, 416L, 624L, 833L) were evaluated in the urban development scenario. To achieve the purpose of this study; a model was developed to simulate daily water balance for the three treatments. Irrigation volumes and water runoff were compared for four soil types and four cistern sizes. Comparisons between total volumes of water runoff were estimated by utilizing different soil types, while comparisons between total potable water used for irrigation were estimated by utilizing different irrigation scheduling methods. This research showed that both Curve Number method and Mass-Balance method resulted in the greatest volumes of water runoff predicted for Silty Clay soil and the least volumes of water runoff predicted for Sand soil. Moreover, increasing cistern sizes resulted in reducing total water runoff and potable water used for irrigation, although not at a statistically significant level. Control treatment that does not utilize a cistern had the greatest volumes of predicted supplemental water among all soil types utilized, while Soil Moisture-based treatment on average had the least volume of predicted supplemental water.
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Gopakumar, R. "Fuzzy Dynamic Wave Models For Flow Routing And Flow Control In Open Channels." Thesis, 2009. http://hdl.handle.net/2005/990.

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Abstract:
The dynamic wave model (the complete form of the saint-Venant equations), as applied to flow routing in irrigation canals or flood routing in natural channels, is associated with parameter and model uncertainties. The parameter uncertainty arises due to imprecision in the estimation of Manning’s n used for calculating the friction slope (sf) in the momentum equation of the dynamic wave model. Accurate estimation of n is difficult due to its dependence on several channel and flow characteristics. The model uncertainty of the dynamic wave model arises due to difficulty in applying the momentum equation to curved channels, as it is a vector equation. The one-dimensional form of the momentum equation is derived assuming that the longitudinal axis of the channel is a straight line, so that the net force vector is equal to the algebraic sum of the forces involved. Curved channel reaches have to be discretized into small straight sub-reaches while applying the momentum equation. Otherwise, two- or three-dimensional forms of the momentum equation need to be adopted. A main objective of the study presented in the thesis is to develop a fuzzy dynamic wave model (FDWM), which is capable of overcoming the parameter and model uncertainties of the dynamic wave model mentioned above, specifically for problems of flow routing in irrigation canals and flood routing in natural channels. It has been demonstrated earlier in literature that the problem of parameter uncertainty in infiltration models can be addressed by replacing the momentum equation by a fuzzy rule based model while retaining the continuity equation in its complete form. The FDWM is developed by adopting the same methodology: i.e. By replacing the momentum equation of the dynamic wave model by a fuzzy rule based model while retaining the continuity equation in its complete form. The fuzzy rule based model is developed based on fuzzification of a new equation for wave velocity, to account for the model uncertainty and backwater effects. A fuzzy dynamic wave routing model (FDWRM) is developed based on application of the FDWM to flow routing in irrigation canals. The fuzzy rule based model is developed based on the observation that inertia dominated gravity wave predominates in irrigation canal flows. Development of the FDWRM and the method of computation are explained. The FDWRM is tested by applying it to cases of hypothetical flow routing in a wide rectangular channel and also to a real case of flow routing in a field canal. For the cases of hypothetical flow routing in the wide rectangular channel, the FDWRM results match well with those of an implicit numerical model (INM), which solves the dynamic wave model; but the accuracy of the results reduces with increase in backwater effects. For the case of flow routing in the field canal, the FDWRM outputs match well with measured data and also are much better than those of the INM. A fuzzy dynamic flood routing model (FDFRM) is developed based on application of the FDWM to flood routing in natural channels. The fuzzy rule based model is developed based on the observation that monoclinal waves prevail during floods in natural channels. The natural channel reach is discredited into a number of approximately uniform sub-reaches and the fuzzy rule based model for each sub-reach is obtained using the discharge (q)–area (a) relationship at its mean section, based on the kleitz-seddon principle. Development of the FDFRM and the method of computation are explained. The FDFRM is tested by applying it to cases of flood routing in fictitious channels and to flood routing in a natural channel, which is described in the HEC-RAS (hydrologic engineering center – river analysis system) application guide. For the cases of flood routing in the fictitious channels, the FDFRM outputs match well with the INM results. For the case of flood routing in the natural channel, optimized fuzzy rule based models are derived using a neuro-fuzzy algorithm, to take the heterogeneity of the channel sub-reaches into account. The resulting FDFRM outputs are found to be comparable to the HEC-RAS outputs. Also, in literature, the dynamic wave model has been applied in the inverse direction for the development of centralized control algorithms for irrigation canals. In the present study, a centralized control algorithm based on inversion of the fuzzy dynamic wave model (FDWM) is developed to overcome the drawbacks of the existing centralized control algorithms. A fuzzy logic based dynamic wave model inversion algorithm (FDWMIA) is developed for this purpose, based on the inversion of the FDWM. The FDWMIA is tested by applying it to two canal control problems reported in literature: the first problem deals with water level control in a fictitious canal with a single pool and the second, with water level control in a real canal with a series of pools (ASCE Test Canal 2). In both cases, the FDWMIA results are comparable to those of the existing centralized control algorithms.
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Buckelew, Juliana Kirsten. "Orchard floor management in young peach [Prunus persica (L.) Batsch.] effects of irrigation, vegetation-free width, and certain PRE herbicides /." 2009. http://www.lib.ncsu.edu/theses/available/etd-04202009-230749/unrestricted/etd.pdf.

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