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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Impact of Mountain Topography and Environmental Flow on the Predictability of Localized Thunderstorms / 地形と環境風が局地的な雷雨の予測可能性に及ぼす影響

Wu, Pin-Ying 25 July 2022 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24124号 / 理博第4852号 / 新制||理||1694(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 竹見 哲也, 教授 榎本 剛, 准教授 重 尚一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
2

Mapping aquifer stress, groundwater abstraction, recharge, and groundwater’s contribution to environmental flows in British Columbia

Forstner, Tara 02 January 2019 (has links)
Groundwater is considered a reliable resource, relatively insensitive to seasonal or even multi-year climatic variation, however quantifying aquifer-scale estimates of stress in diverse hydrologic environments is particularly difficult due to data scarcity and the limited number of techniques in deriving stress parameters, such as use and availability, which can be applied over a large spatial area. The scope of this project is to derive aquifer-scale estimates of annual volumes for groundwater withdrawal, recharge, and groundwater’s contribution to environmental flows as a means to provide screening level estimates of aquifer-scale stress using the groundwater footprint. British Columbia (BC) has mapped and classified more than 1100 aquifers, but the level of development for each aquifer has always been subjectively based on well density or the anecdotal knowledge of groundwater use. Sectoral groundwater use is critical for local regions and aquifer-scale groundwater stress studies which are significantly impacted by changes in the groundwater use nominator. Results suggest that BC uses a total of ~562 million cubic meters of groundwater annually. The largest annual groundwater use by major sectors is agriculture (38%), finfish aquaculture (21%), industrial (16%), municipal water distribution systems (15%), and domestic private well users (11%). Estimating recharge uses multi-scale methods to examine the recharge mechanisms and provide a more reliable recharge estimate in complex mountainous terrain. Local-scale recharge was estimated using the water table fluctuation (WTF) method outlined by Cuthbert (2014). Aquifer-scale recharge was quantified using a quasi-2D water balance model and generalized aquifer parameters of soil and aquifer material, regional climate, and water table depth. Regional scale aquifer recharge was attributed the areal average recharge flux modelled by the global hydrologic model, PCR-GLOBWB. Results show that generally recharge predictably varies with precipitation and that the average recharge is 791 mm for the local-scale method, 462 mm (32% of precipitation) for the aquifer-scale and 393 mm (33%) for the global hydrologic model. This study estimates groundwater’s contribution to environmental flows across the province for this first time using two separate approaches. The first approach uses the groundwater presumptive standard, which is a general standard for managing groundwater pumping. The second method introduces a novel approach for estimating the contribution of groundwater to environmental flows using the existing environmental flow needs framework and an understanding of low flow zone hydrology. In general, both methods show larger contributions from groundwater to environmental flows in the Lower Mainland and southern Vancouver Island compared to the Interior. For each aquifer, the groundwater footprint (expressed as the unitless ratio of groundwater footprint to aquifer area) is calculated four times; using results from each of the two methods used to estimate recharge and each of the two methods used to estimate the groundwater contribution to environmental flows. Of the unconfined aquifers (n = 404) in the province, 43 aquifers (11%) are stressed with high certainty, 32 aquifers (8%) are stressed with low certainty, 296 aquifers (70%) are less stressed, and 29 aquifers (11%) were not included due to missing parameters or issues where modelled recharge was less than environmental flows. / Graduate / 2019-10-25
3

Numerical Simulation of Environmental Flow over Urban Landscape for Applications to Renewable Energy

January 2015 (has links)
abstract: Development of renewable energy solutions has become a major interest among environmental organizations and governments around the world due to an increase in energy consumption and global warming. One fast growing renewable energy solution is the application of wind energy in cities. To qualitative and quantitative predict wind turbine performance in urban areas, CFD simulation is performed on real-life urban geometry and wind velocity profiles are evaluated. Two geometries in Arizona is selected in this thesis to demonstrate the influence of building heights; one of the simulation models, ASU campus, is relatively low rise and without significant tall buildings; the other model, the downtown phoenix model, are high-rise and with greater building height difference. The content of this thesis focuses on using RANS computational fluid dynamics approach to simulate wind acceleration phenomenon in two complex geometries, ASU campus and Phoenix downtown model. Additionally, acceleration ratio and locations are predicted, the results are then used to calculate the best location for small wind turbine installments. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015
4

Regleringens effekter på vattenståndsvariationer nedströms Viforsens kraftverk i Ljungan / The effects of regulation on fluctuations in waterlevel downstream of Viforsen's powerplant in Ljungan

Robin, Eklund January 2021 (has links)
Hydropower production has advantages but also negative ecological consequences. Thisstudy analyzes the degree of flow variations downstream Viforsen's power plant to investigate how well the regulated flow is re-regulated towards a more natural flow pattern. The studyalso examine effects of the regulation on valuable salmon habitats in the section from Viforsen's power plant down to the sea and whether there is a downstream gradient in the presence of different fish species. Data on water level changes was obtained by installingthree pressure loggers in a gradient downstream of the Viforsen power plant. Collection of hourly flow-data in Viforsen and Vindelälven have been part of the data in the survey. The presence of different species of fish was determined by examination of the Swedish electrofishing registry. Results showed a strong correlation between flow and water level at all three sites in Ljungan and there is no ecologically significant dampening of water level fluctuations downstream Viforsen. The current requirement for a minimum discharge of 30 m3/s is too low as important salmon habitats risk being drained. The strong correlation between water levels and flow that this study shows make it possible to map in more detail the risks of valuable salmon habitats drying up. The results also showed that typically marine species” of fish are much more common in Viforsen than in Vindelälven. This study emphasizes that ecologically sustainable flows are complex and relevant field investigations at each watercourse are necessary when reconsidering and designing the new environmental conditions.
5

Modelagem de escoamento em aqüiferos longos baseada no método de elementos analíticos / Elonged aquifer flow modeling based on analytic element method

Batista, José Anderson do Nascimento 10 February 2006 (has links)
O método de elementos analíticos tem se mostrado uma alternativa conveniente para a construção de modelos regionais de escoamento subterrâneo. O método utiliza soluções elementares analíticas e, portanto, não necessitam de contornos artificiais. Entretanto, a caracterização de fronteiras externas de aqüíferos considerados longos (aqüíferos longos) acarreta dúvidas quanto à presença do efeito de borda na simulação. Assim, neste trabalho, o método de elementos analíticos é estendido para a modelagem de escoamentos em aqüíferos longos eliminando-se a possibilidade da presença de efeitos de borda. O domínio desses aqüíferos é mapeado em um semi-plano utilizando-se a transformação de Schwarz-Christoffel. Dessa forma, elementos de regime estacionário são mapeados juntamente com o domínio para o semi-plano e, portanto, sua formulação é modificada. Os contornos do semi-plano, por sua vez, são representados pelo método de imagens. Elementos de escoamento transiente são abordados utilizando-se a formulação de Zaadnoordijk. São realizadas correções algébricas e computacionais na formulação desses elementos. No entanto, o mapeamento de domínio não é extensivo aos elementos transientes. Sua aplicação em aqüíferos longos é feita de maneira aproximada utilizando-se apenas o método de imagens diretamente sobre o aqüífero. Em seguida, a extensão proposta para o método de elementos analíticos é analisada em um problema hipotético. Finalmente, é feita uma modelagem para a avaliação de impactos ambientais devidos a um sistema de captação de água localizado em uma porção do aqüífero Barreiras no Estado do Rio Grande do Norte sobre a Lagoa do Bonfim. O modelo é calibrado em regime permanente fornecendo uma estimativa de recarga de 24 mm/mês e, então, estima os impactos permanentes do sistema sobre a Lagoa do Bonfim, onde é feita a captação. O impacto do bombeamento reduz aproximadamente 5,36 m do nível de água natural da lagoa. Um cenário de seca é, também, simulado em regime transiente. A partir dos resultados obtidos avalia-se que dois meses de ausência de recarga direta aumentam aproximadamente 0,5 m a redução do nível de água da Lagoa do Bonfim / The analytic element method has shown itself an elegant alternative to regional groundwater flow modeling. The method applies elementary analytic solutions and, therefore, artificial boundaries are not a necessity. However, frontiers of such considered elonged aquifers carries out some questions about edging effects in the model results. In this work, the analytic element method is extended to elonged aquifer flow completely eliminating any edging effect. To do this, such aquifers are mapped into a semi-plan by means of the Schwarz-Christoffel transform. Next, steady flow elements are mapped accordingly to the domain transformation and consequently its formulas are modified suitably. Then, method of image gives boundary conditions in semi-plan. Transient flow elements due to Zaadnoordijk are considered. Mistakes in algebraic and computational aspects were corrected. Nevertheless, domain mappings are not performed to transient elements. Appliance of such elements to elonged aquifers is performed in an approximated manner with the method of image just upon the aquifer. After that, a hypothetic example is performed in order to analyze the new elements, given successful results. Then, a case study is developed in order to assess the impact due to a water supply system in the Barreiras aquifer, Rio Grande do Norte State, on Bonfim Lake. The model is calibrated, obtaining the recharge rate parameter equal to 24 mm/month, and then is used to evaluate water level depletion in Bonfim Lake. Water level changing in Bonfim Lake is given by the steady state flow 5.36 m down. Finally, a transient flow model is built in order to obtain water level changes due to recharge absence. According to results, recharge absence during two month long enlarges 0.5 m, approximately, water depletion in Bonfim Lake
6

Análise do impacto do Sistema Cantareira sobre o regime de vazões na bacia do rio Piracicaba / Analysis of the Cantareira System impact on the flow regime in Piracicaba river basin

Frederice, Aline 02 October 2014 (has links)
Neste trabalho, buscou-se caracterizar o regime natural de vazões dos principais rios da bacia do rio Piracicaba e identificar as alterações ocorridas nesse regime, principalmente em decorrência da implantação dos reservatórios do Sistema Cantareira. As análises foram feitas com base nas séries de vazões médias diárias de seis postos fluviométricos situados na bacia (prefixo DAEE: 3D-001, 3D-002, 3D- 006, 3D-009, 4D-001 e 4D-007). Foi utilizado o software IHA (Indicators of Hydrologic Alteration), o qual calcula 33 parâmetros hidrológicos relevantes ecologicamente, que caracterizam a magnitude, o tempo, a frequência, a duração e a taxa de flutuações das vazões, além de dividir a vazão ambiental em cinco componentes: vazões extremas baixas, vazões baixas, pulsos de vazão alta, pequenas cheias e grandes cheias. As séries foram divididas em dois períodos, pré e pós impacto, sendo considerado como ano do impacto o ano correspondente a data da ruptura da homogeneidade das séries de vazões, verificada por meio do teste não paramétrico de Pettitt. Foram determinados pelo software IHA, para o período pós impacto, os fatores de alteração hidrológica de cada um dos 33 parâmetros hidrológicos e as mudanças ocorridas nos componentes da vazão ambiental. Para os rios influenciados pelo Sistema Cantareira, foi constatado que no período pós impacto (a partir das décadas de 1970/80), no geral, houve uma diminuição nas vazões médias de aproximadamente 24% (posto 3D-006) no rio Atibaia, 50% (posto 3D-009) e 34% (posto 4D-001) no rio Jaguari, e 14% (posto 4D- 007) no rio Piracicaba, principalmente no período seco (abril a setembro). Verificou-se também uma redução no valor da mediana das vazões mínimas anuais de 7 dias consecutivos igual a 25% (posto 3D-006), 56% (posto 3D-009), 43% (posto 4D-001) e 15% (posto 4D-007) e aumento na duração e na frequência de ocorrência das vazões mais baixas. Foi também constatado, nesses postos, a diminuição na duração das vazões altas, bem como o aumento nas taxas de ascensão e recessão dessas vazões. As mudanças mais significativas ocorreram no rio Jaguari, seguido pelo rio Atibaia e foram menos significativas no rio Piracicaba, o qual se encontra mais distante dos reservatórios. Já para o rio Camanducaia (sem influência do Sistema Cantareira), após a década de 1970, não houve mudança no valor da mediana das vazões mínimas anuais de 7 dias consecutivos e constatou-se, no geral, um aumento nas vazões médias de aproximadamente 21% (posto 3D-001) e 14% (posto 3D-002), assim como o aumento na frequência de ocorrência das vazões máximas, porém, as mudanças não foram tão significativas como nos demais rios. / The aim in this paper was to characterize the natural flow regime of the main rivers of Piracicaba River basin and identify the alterations in this regime, mainly due to the implementation of Cantareira System reservoirs. The analyzes were based on the average daily flow series from six fluviometric stations in the basin (DAEE prefix: 3D- 001, 3D-002, 3D-006, 3D-009, 4D-001 and 4D-007). The IHA (Indicators of Hydrologic Alteration) software was used to calculate 33 hydrological parameters ecologically relevant, that characterizes the magnitude, timing, frequency, duration and rate of flow changes, besides spliting the environmental flow into five components: extreme low flows, low flows, high flow pulses, small floods and large floods. The daily flow series were divided into two periods, pre and post impact, and it was considered as the year of the impact the year that corresponding to the breaking of homogeneity date from the flow series, verified by the nonparametric Pettitt test. It was determined by the IHA software, for post impact period, the Hydrological Alteration factors of the 33 hydrologic parameters and the changes in the environmental flow components. For the rivers influenced by Cantareira System, it was observed that in the post impact period (from 1970/80s), overall, there was a decrease in the mean flow, approximately 24% (3D-006 station) in Atibaia River, 50% (3D-009 station) and 34% (4D-001 station) in Jaguari River, and 14% (4D-007 station) in Piracicaba River, mainly in the dry season (April to September). There was also a decrease in the median of the annual seven days minimum flows by 25% (3D- 006 station), 56% (3D-009 station), 43% (4D-001 station) and 15% (4D-007 station), and an increase in the frequency and duration of the lower flows. It was also found for these stations a decrease in the duration of high flows as well as an increase in the rise rates and the fall rates of these flows. The most significant changes occurred in Jaguari River, followed by the Atibaia River and were less significant in the Piracicaba River, which is the farthest from the reservoirs. For the Camanducaia River (without influence from Cantareira System), after the 1970s, there was no change in the median of the annual seven days minimum flows and it was observed, overall, an increase in the mean flow by 21% (3D-001 station) and 14% (3D-002 station), as well as an increase in the frequency of the maximum flows, however, the changes were not as significant as in the other rivers.
7

EFFICIENT WATER ALLOCATION IN A HETEROGENEOUS CATCHMENT SETTING

Lee, Lisa Yu-Ting January 2007 (has links)
Doctor of Philosophy / The problem of water scarcity has become one of the most controversial topics in Australia over the past decades, with particular focus being the ‘sustainable’ allocation of water between extractive and environmental purposes. Geographical factors are defining the extreme variability in climate and water supply in Australia and, in the past, this was used as a rationale for the construction of large irrigation projects to deliver water to rural, urban, and industrial users. During this ‘expansionary’ phase of Australia’s water use sector, the cost of augmenting supply was relatively low and environmental considerations were secondary to the development imperative. As a result, water resources became over-allocated for extractive uses spurred on by consistent underpricing of water, which indicated a failure to reflect the true cost of water supply. As Australia’s water economy entered a ‘mature’ phase, it was no longer possible to increase supply cheaply as the most easily accessible water resources had already been captured. This was followed by widespread environmental degradation manifested in the Murray- Darling Basin, the nation’s largest river basin which hosts much of Australia’s agricultural production. Consequently, the focus shifted towards demand management, leading to a myriad of regulation aimed at increasing the allocative efficiency of scarce water resources. Towards this end, substantial government funding was injected into the various initiatives throughout the water reform process. Despite the on-going government activities in the area of water reform, the understanding of the actual economic impact and environmental outcomes of various water policies in practice remains limited. In the absence of such understanding, the effectiveness of various government water initiatives is ambiguous and inevitably compromised. The present study addresses this knowledge gap by establishing a method for evaluating the economic and environmental outcomes of environmentally-oriented polices that affect irrigated industries in a catchment. The method is based on an integrated biophysical and economic modelling approach, which enables spatial relationships to be captured accurately allowing a more realistic analysis. Information generated from a computer based biophysical simulation model form the basis of an economic optimisation model with constraints pertaining to environmental targets and water supply limits. The economic model consists of a linear programming and dynamic programming component, and involves the optimisation of resource use from a catchment manager’s perspective, seeking to achieve efficient resource use but at the same time conform to given environmental objectives. This embedded linear and dynamic programming approach was required to determine the optimal intra-seasonal and inter-seasonal water allocation, given various catchment environmental targets. The interdisciplinary approach enables the economic and ecological outcomes of the catchment management policies to be simulated and assessed at a spatially explicit scale, due to the link to Geographical Information Systems (GIS) in the biophysical model. The overall objective was to create a decision-making framework that could be used to determine the least-cost means of meeting environmental targets and resource constraints. The solutions to the analysis are directly applicable to the case study, the Mooki catchment in northern New South Wales (NSW), but with an adaptable framework that can be applied to other catchments. Specific objectives include an evaluation of the possibility of using alternative irrigation systems, as well as an evaluation of the benefits that can be realised by establishing water market, in the light of environmentally-oriented catchment policies for the case study. The economic cost of achieving environmental targets pertaining to environmental flow requirements and salinity reduction, in the form of end-of-valley salinity targets, was explicitly calculated through the economic model. While salinity targets have been set for NSW catchments, the practicality of such targets is in question, given the substantial reductions in water allocation to irrigation activities, which is one of the key contributors to deep-drainage. An additional objective in this study was therefore to investigate the value of having deep drainage targets. A further consideration is the effect of “external agents” in the form of government plans to buyback entitlements from irrigation districts, or the possibility of significant water rights purchases from mining industries. The implications of external water market entrants on the regional agricultural industry were examined.
8

EFFICIENT WATER ALLOCATION IN A HETEROGENEOUS CATCHMENT SETTING

Lee, Lisa Yu-Ting January 2007 (has links)
Doctor of Philosophy / The problem of water scarcity has become one of the most controversial topics in Australia over the past decades, with particular focus being the ‘sustainable’ allocation of water between extractive and environmental purposes. Geographical factors are defining the extreme variability in climate and water supply in Australia and, in the past, this was used as a rationale for the construction of large irrigation projects to deliver water to rural, urban, and industrial users. During this ‘expansionary’ phase of Australia’s water use sector, the cost of augmenting supply was relatively low and environmental considerations were secondary to the development imperative. As a result, water resources became over-allocated for extractive uses spurred on by consistent underpricing of water, which indicated a failure to reflect the true cost of water supply. As Australia’s water economy entered a ‘mature’ phase, it was no longer possible to increase supply cheaply as the most easily accessible water resources had already been captured. This was followed by widespread environmental degradation manifested in the Murray- Darling Basin, the nation’s largest river basin which hosts much of Australia’s agricultural production. Consequently, the focus shifted towards demand management, leading to a myriad of regulation aimed at increasing the allocative efficiency of scarce water resources. Towards this end, substantial government funding was injected into the various initiatives throughout the water reform process. Despite the on-going government activities in the area of water reform, the understanding of the actual economic impact and environmental outcomes of various water policies in practice remains limited. In the absence of such understanding, the effectiveness of various government water initiatives is ambiguous and inevitably compromised. The present study addresses this knowledge gap by establishing a method for evaluating the economic and environmental outcomes of environmentally-oriented polices that affect irrigated industries in a catchment. The method is based on an integrated biophysical and economic modelling approach, which enables spatial relationships to be captured accurately allowing a more realistic analysis. Information generated from a computer based biophysical simulation model form the basis of an economic optimisation model with constraints pertaining to environmental targets and water supply limits. The economic model consists of a linear programming and dynamic programming component, and involves the optimisation of resource use from a catchment manager’s perspective, seeking to achieve efficient resource use but at the same time conform to given environmental objectives. This embedded linear and dynamic programming approach was required to determine the optimal intra-seasonal and inter-seasonal water allocation, given various catchment environmental targets. The interdisciplinary approach enables the economic and ecological outcomes of the catchment management policies to be simulated and assessed at a spatially explicit scale, due to the link to Geographical Information Systems (GIS) in the biophysical model. The overall objective was to create a decision-making framework that could be used to determine the least-cost means of meeting environmental targets and resource constraints. The solutions to the analysis are directly applicable to the case study, the Mooki catchment in northern New South Wales (NSW), but with an adaptable framework that can be applied to other catchments. Specific objectives include an evaluation of the possibility of using alternative irrigation systems, as well as an evaluation of the benefits that can be realised by establishing water market, in the light of environmentally-oriented catchment policies for the case study. The economic cost of achieving environmental targets pertaining to environmental flow requirements and salinity reduction, in the form of end-of-valley salinity targets, was explicitly calculated through the economic model. While salinity targets have been set for NSW catchments, the practicality of such targets is in question, given the substantial reductions in water allocation to irrigation activities, which is one of the key contributors to deep-drainage. An additional objective in this study was therefore to investigate the value of having deep drainage targets. A further consideration is the effect of “external agents” in the form of government plans to buyback entitlements from irrigation districts, or the possibility of significant water rights purchases from mining industries. The implications of external water market entrants on the regional agricultural industry were examined.
9

Impacto da adoção de vazões ecológicas no baixo curso do Rio São Francisco sobre a geração hidrelétrica.

Amorim, Flávia Bezerra January 2009 (has links)
Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2013-04-10T19:33:40Z No. of bitstreams: 1 Flávia.pdf: 6019408 bytes, checksum: d4679f5b8c0dda047c7265c24402edac (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-13T20:01:13Z (GMT) No. of bitstreams: 1 Flávia.pdf: 6019408 bytes, checksum: d4679f5b8c0dda047c7265c24402edac (MD5) / Made available in DSpace on 2013-04-13T20:01:13Z (GMT). No. of bitstreams: 1 Flávia.pdf: 6019408 bytes, checksum: d4679f5b8c0dda047c7265c24402edac (MD5) Previous issue date: 2009 / Esta dissertação discute uma abordagem para o processo de determinação de vazões ecológicas, baseada no “paradigma das vazões naturais” proposto por Poff et al. (1997), mas, ainda, de forma a contemplar os múltiplos usos da água. Os estudos desenvolvidos visaram identificar o impacto sobre a geração hidrelétrica na hipótese de adoção de um regime dinâmico de vazões (RDV) no baixo trecho do Rio São Francisco.Isso foi realizado por meio de simulação de cenários, os quais se propõem a atender demandas ambientais e ecológicas, em condição distinta das vazões mínimas atuais mantidas a jusante dos barramentos. Para essa simulação foi usado esquema matemático de fluxos em rede, com o modelo ‘AcquaNet’,computando-se a potência gerada pelo sistema de usinas hidrelétricas da CHESF em termos médios mensais.Consideraram-se os RDVs sem e com restrições de vazões, estas referentes às condições atualmente praticadas quanto à máxima cota de inundação (8.000 m3/s) e quanto às cotas mínimas de captação e aspectos ambientais (1.300 e 1.100 m3/s). Também, um bloco de simulações foi realizado considerando diferentes condições hídricas da bacia, nas quais as exigências quanto a RDVs mudavam para cada condição.Essa última abordagem corresponderia a situações de utilização da previsão climática na operação dos reservatórios. Dos diversos resultados obtidos, verifica-se que seria plausível se praticar certos regimes de vazões, contemplando momentos de cheias e vazantes que reproduzam parcialmente condições do regime natural e, ainda, considerando restrições impostas pela realidade atual, sem comprometer significativamente a produção hidrelétrica. A adoção de RDVs que consideram maiores descargas, por impactarem a produção de energia mais fortemente, deveriam ser objeto de discussão pela sociedade, além de contemplar outros usos não explicitamente considerados neste estudo. A consideração das vazões ecológicas nos usos múltiplos das águas é fundamental para conciliar a saúde dos ecossistemas aquáticos com as necessidades humanas. Esta dissertação visa ser uma contribuição inicial para esse caminho. / Salvador
10

Modelagem de escoamento em aqüiferos longos baseada no método de elementos analíticos / Elonged aquifer flow modeling based on analytic element method

José Anderson do Nascimento Batista 10 February 2006 (has links)
O método de elementos analíticos tem se mostrado uma alternativa conveniente para a construção de modelos regionais de escoamento subterrâneo. O método utiliza soluções elementares analíticas e, portanto, não necessitam de contornos artificiais. Entretanto, a caracterização de fronteiras externas de aqüíferos considerados longos (aqüíferos longos) acarreta dúvidas quanto à presença do efeito de borda na simulação. Assim, neste trabalho, o método de elementos analíticos é estendido para a modelagem de escoamentos em aqüíferos longos eliminando-se a possibilidade da presença de efeitos de borda. O domínio desses aqüíferos é mapeado em um semi-plano utilizando-se a transformação de Schwarz-Christoffel. Dessa forma, elementos de regime estacionário são mapeados juntamente com o domínio para o semi-plano e, portanto, sua formulação é modificada. Os contornos do semi-plano, por sua vez, são representados pelo método de imagens. Elementos de escoamento transiente são abordados utilizando-se a formulação de Zaadnoordijk. São realizadas correções algébricas e computacionais na formulação desses elementos. No entanto, o mapeamento de domínio não é extensivo aos elementos transientes. Sua aplicação em aqüíferos longos é feita de maneira aproximada utilizando-se apenas o método de imagens diretamente sobre o aqüífero. Em seguida, a extensão proposta para o método de elementos analíticos é analisada em um problema hipotético. Finalmente, é feita uma modelagem para a avaliação de impactos ambientais devidos a um sistema de captação de água localizado em uma porção do aqüífero Barreiras no Estado do Rio Grande do Norte sobre a Lagoa do Bonfim. O modelo é calibrado em regime permanente fornecendo uma estimativa de recarga de 24 mm/mês e, então, estima os impactos permanentes do sistema sobre a Lagoa do Bonfim, onde é feita a captação. O impacto do bombeamento reduz aproximadamente 5,36 m do nível de água natural da lagoa. Um cenário de seca é, também, simulado em regime transiente. A partir dos resultados obtidos avalia-se que dois meses de ausência de recarga direta aumentam aproximadamente 0,5 m a redução do nível de água da Lagoa do Bonfim / The analytic element method has shown itself an elegant alternative to regional groundwater flow modeling. The method applies elementary analytic solutions and, therefore, artificial boundaries are not a necessity. However, frontiers of such considered elonged aquifers carries out some questions about edging effects in the model results. In this work, the analytic element method is extended to elonged aquifer flow completely eliminating any edging effect. To do this, such aquifers are mapped into a semi-plan by means of the Schwarz-Christoffel transform. Next, steady flow elements are mapped accordingly to the domain transformation and consequently its formulas are modified suitably. Then, method of image gives boundary conditions in semi-plan. Transient flow elements due to Zaadnoordijk are considered. Mistakes in algebraic and computational aspects were corrected. Nevertheless, domain mappings are not performed to transient elements. Appliance of such elements to elonged aquifers is performed in an approximated manner with the method of image just upon the aquifer. After that, a hypothetic example is performed in order to analyze the new elements, given successful results. Then, a case study is developed in order to assess the impact due to a water supply system in the Barreiras aquifer, Rio Grande do Norte State, on Bonfim Lake. The model is calibrated, obtaining the recharge rate parameter equal to 24 mm/month, and then is used to evaluate water level depletion in Bonfim Lake. Water level changing in Bonfim Lake is given by the steady state flow 5.36 m down. Finally, a transient flow model is built in order to obtain water level changes due to recharge absence. According to results, recharge absence during two month long enlarges 0.5 m, approximately, water depletion in Bonfim Lake

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