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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.
31

Avaliação da sustentabilidade do perímetro irrigado Poção da Ribeira em Itabaiana, Sergipe

Silva, Paulo Silas Oliveira da 29 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / As one of the objectives of the agreed millennium among 191 countries by the United Nations (UN) in 2000, the sustainability is a goal that must be pursued in every human activity. The irrigated agriculture has been reported to consume about 70% of the water used on the planet. In face of the global climate change scenarios and of water scarcity, sustainable irrigated agriculture practices will have to be measured, and this has been realized using tools at example of the sustainability indicators. The irrigated perimeter Poção da Ribeira in Sergipe, Brazil, has been cited in the academic space to presents difficulties in managing water resources. In face this, the objective of this study was to evaluate the sustainability of irrigated perimeter Poção da Ribeira through environmental, social and economic indicators. For this, the work was divided into three parts corresponding to specific objectives: assess the Ribeira reservoir water quality through risk indicators for irrigated agriculture; assess agrienvironmental quality of Poção da Ribeira soils irrigated perimeter through of chemical indicators; assess the sustainable condition of the perimeter through a sustainability index composed of environmental, social and economic indicators. The results showed that the water quality of the Ribeira reservoir presents phytotoxicity risk for chlorine and sodium during the dry season in the region, and imminent risk of microbiological contamination by fecal coliforms. The irrigated perimeter soils showed lows organic matter contents and cation exchange capacity and high levels of phosphorus and potassium indicating an intensive and inadequate tillage for the maintenance of fertility and soil conservation. It was concluded that overcoming individuality through the social organization, the adoption of soil conservation practices, the water sanitary treatment, the reduction and efficient use of water for irrigation, the abandonment of pesticides use, the implementation of technical and extension assistance rural services, education and the technical vocational training, public security, the monitoring of water and soil, are needs that can improve the current situation and therefore the pursuit for condition ideal sustainability. / Como um dos objetivos do milênio pactuados entre 191 países por meio da Organização das Nações Unidas (ONU) em 2000, a sustentabiliade é uma meta que deve ser buscada em cada atividade humana. A agricultura irrigada tem sido relatada por consumir cerca de 70% da água utilizada no planeta. Diante do panorama mundial de mudanças climáticas e escassez de recursos hídricos, práticas sustentáveis na agricultura irrigada precisam ser mensuradas, e para isso tem-se buscado o uso de ferramentas a exemplo dos indicadores de sustentabilidade. O perímetro irrigado Poção da Ribeira em Itabaiana, Sergipe, Brasil tem sido citado, no meio acadêmico, por apresentar dificuldades na gestão de recursos hídricos. Diante disto, este trabalho teve por objetivo geral avaliar a sustentabilidade do perímetro irrigado Poção da Ribeira através de indicadores ambientais, sociais e econômicos. Para tanto o trabalho foi dividido em três partes correspondentes aos objetivos específicos: avaliar a qualidade da água do reservatório da Ribeira através de indicadores de risco para agricultura irrigada; avaliar a qualidade agroambiental dos solos do perímetro irrigado Poção da Ribeira através de indicadores químicos; avaliar a condição sustentável do perímetro através de um índice de sustentabilidade composto por indicadores ambientais, sociais e econômicos. Os resultados permitiram concluir que a qualidade da água do reservatório da Ribeira apresenta riscos de fitotoxidade por cloro e sódio durante o período seco para a região, além de risco iminente de contaminação microbiológica por coliformes termotolerantes. Os solos do perímetro irrigado apresentam baixos teores de matéria orgânica e capacidade de troca catiônica e valores elevados de fósforo e potássio indicando um manejo intensivo e inadequado para a manutenção da fertilidade e conservação do solo. Concluiu-se que a superação da individualidade pela organização social, a adoção de práticas conservacionistas do solo, o tratamento sanitário da água, redução e eficiência no consumo da água para irrigação, o abandono do uso de agrotóxicos, a implantação de serviços públicos de assistência técnica rural, educação e capacitação profissional técnica e extensão rural, segurança pública e monitoramento de água e solo, são necessidades que podem melhorar a situação atual e consequentemente a busca da condição de sustentabilidade ideal.
32

Performance Assessment and Management of Groundwater in an Irrigation Scheme by Coupling Remote Sensing Data and Numerical Modeling Approaches

Usman, Muhammad 08 April 2016 (has links)
The irrigated agriculture in the Lower Chenab Canal (LCC) of Pakistan is characterized by huge water utilization both from surface and groundwater resources. Need of utilization of water from five rivers in Punjab province along with accelerated population growth has forced the construction of world’s largest irrigation network. Nevertheless, huge irrigation infrastructure, together with inappropriate drainage infrastructure, led to a build-up of shal-low groundwater levels, followed by waterlogging and secondary salinization in the soil profile. Following this era, decreased efficiency of irrigation supply system along with higher food demands had increased burdens on groundwater use, which led to a drop in groundwater levels in major parts of LCC. Previous studies in the study region revealed lacking management and maintenance of irrigation system, inflexible irrigation strategies, poor linkages between field level water supply and demands. No future strategy is present or under consideration to deal with this long time emerged groundwater situation particularly under unchanged irrigation water supply and climate change. Therefore, there is an utmost importance to assess the current profile of water use in the irrigation scheme and to device some workable strategies under future situations of land use and climate change. This study aims to investigate the spatio-temporal status of water utilization and performance of irrigation system using remote sensing data and techniques (SEBAL) in combination with other point data. Different irrigation performance indicators including equity, adequacy and reliability using evaporation fraction as main input parameter are utilized. Current profiles of land use/land cover (LULC) areas are assessed and their change detections are worked out to establish realistic future scenarios. Spatially distributed seasonal net recharge, a very important input parameter for groundwater modeling, is estimated by employing water balance approaches using spatial data from remote sensing and local norms. Such recharge results are also compared with a water table fluctuation approach. Following recharge estimation, a regional 3-D groundwater flow model using FEFLOW was set up. This model was calibrated by different approaches ranging from manual to automated pilot point (PP) approach. Sensitivity analysis was performed to see the model response against different model input parameters and to identify model regions which demand further improvements. Future climate parameters were downscaled to establish scenarios by using statistical downscaling under IPCC future emission scenarios. Modified recharge raster maps were prepared under both LULC and climate change scenarios and were fed to the groundwater model to investigate groundwater dynamics. Seasonal consumptive water use analysis revealed almost double use for kharif as compared to rabi cropping seasons with decrease from upper LCC to lower regions. Intra irrigation subdivision analysis of equity, an important irrigation performance indicator, shows less differences in water consumption in LCC. However, the other indicators (adequacy and reliability) indicate that the irrigation system is neither adequate nor reliable. Adequacy is found more pronounced during kharif as compared to rabi seasons with aver-age evaporation fraction of 0.60 and 0.67, respectively. Similarly, reliability is relatively higher in upper LCC regions as compared to lower regions. LULC classification shows that wheat and rice are major crops with least volatility in cultivation from season to season. The results of change detection show that cotton exhibited maximum positive change while kharif fodder showed maximum negative change during 2005-2012. Transformation of cotton area to rice cultivation is less conspicuous. The water consumption in upper LCC regions with similar crops is relatively higher as compared to lower regions. Groundwater recharge results revealed that, during the kharif cropping seasons, rainfall is the main source of recharge followed by field percolation losses, while for rabi cropping seasons, canal seepage remains the major source. Seasonal net groundwater recharge is mainly positive during all kharif seasons with a gradual increase in groundwater level in major parts of LCC. Model optimization indicates that PP is more flexible and robust as compared to manual and zone based approaches. Different statistical indicators show that this method yields reliable calibration and validation as values of Nash Sutcliffe Efficiency are 0.976 and 0.969, % BIAS are 0.026 and -0.205 and root mean square errors are 1.23 m and 1.31 m, respectively. Results of model output sensitivity suggest that hydraulic conductivity is a more influential parameter in the study area than drain/fillable porosity. Model simulation results under different scenarios show that rice cultivation has the highest impact on groundwater levels in upper LCC regions whereas major negative changes are observed for lower parts under decreased kharif fodder area in place of rice, cotton and sugarcane. Fluctuations in groundwater level among different proposed LULC scenarios are within ±1 m, thus showing a limited potential for groundwater management. For future climate scenarios, a rise in groundwater level is observed for 2011 to 2025 under H3A2 emission regime. Nevertheless, a drop in groundwater level is expected due to increased crop consumptive water use and decreased precipitations under H3A2 scenario for the periods 2026-2035 and 2036-2045. Although no imminent threat of groundwater shortage is anticipated, there is an opportunity for developing groundwater resources in the lower model regions through water re-allocation that would be helpful in dealing water shortages. The groundwater situation under H3B2 emission regime is relatively complex due to very low expectation of rise in groundwater level through precipitation during 2011-2025. Any positive change in groundwater under such scenarios is mainly associated with changes in crop consumptive water uses. Consequently, water management under such situation requires revisiting of current cropping patterns as well as augmenting water supply through additional surface water resources.:ABSTRACT VIII ZUSAMMENFASSUNG X ACRONYMS 1 Chapter 1 3 GENERAL INTRODUCTION 3 1 Groundwater for irrigated agriculture 3 2 Groundwater development in Pakistan 4 3 Study area 6 4 History of groundwater use in the study area 7 5 Research agenda 8 5.1 Problem statement 8 5.2 Objectives and scope of the study 9 Chapter 2 12 OVERVIEW OF PUBLICATIONS 12 Chapter 3 16 GENERAL CONCLUSIONS AND POLICY RECOMMENDATIONS 16 REFERENCES 20 ANNEXES 23 ACKNOWLEDGEMENTS 123
33

Avaliação de custos de água e energia elétrica para frutíferas irrigadas no Nordeste Brasileiro. / Evaluation of water and electric energy costs for irrigated fruit trees in the Brazilian Northeast.

FARIAS, Soahd Arruda Rached. 04 June 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-04T18:21:18Z No. of bitstreams: 1 SOAHD ARRUDA RACHED FARIAS - TESE PPGEA 2006..pdf: 106641017 bytes, checksum: 00962c5527d6dea906019cefb658d12c (MD5) / Made available in DSpace on 2018-06-04T18:21:18Z (GMT). No. of bitstreams: 1 SOAHD ARRUDA RACHED FARIAS - TESE PPGEA 2006..pdf: 106641017 bytes, checksum: 00962c5527d6dea906019cefb658d12c (MD5) Previous issue date: 2006-10 / Propõe-se, no presente trabalho, uma avaliação de custos de energia e água. dentro do planejamento agrícola irrigado obtendo-se, inicialmente, as demandas brutas de água e energia para as culturas do coco anão (Cocos nucifera L.), mamão {Carica papayá) e banana pacovã {Musa spp) em 14 municípios do Nordeste Brasileiro e se utilizando dois sistemas pressuridados, através de uma simulação de projeto agronómico de irrigação. O menor consumo de água anual previsto para irrigação foi na localidade de Mamanguape, PB, necessitando-se apenas de 37,4%; 35,5% e 41,4% respectivamente, para as culturas de coco anão, mamão e Banana pacovã, com relação ao consumo obtido na localidade de maior consumo (Petrolina, PE). Obtiveram-se áreas potenciais para irrigação empregando-se o mesmo conjunto eletrobomba (7,5 CV e vazão de 22 m3 h"1) para as culturas de coco anão, mamão e banana pacovã, respectivamente, de 13,65 ha (localizada) e 4,54 ha (aspersão); 9,45 ha (localizada) e 5,18 ha (aspersão) e 6,25 ha (localizada) e 3,63 ha (Aspersão). A crescente demanda de água e energia ocorreu praticamente combinada pela escala de classificação climática de Hargreaves (1974b), onde percorreu a menor necessidade de complementação o município dc Mamanguape, PB (Clima Seco-Úmido), sequenciado, Pacatuba, SE, Maceió, AL, Aracaju, SE, Natal, RN, Campina Grande, PB, posteriormente os municípios Acaraú, CE, Aracati, CE e Touros, RN de clima Semi-Arido, Canindé de São Francisco, SE, Sousa, PB e Jaguaribe, CE com clima Árido e Açu, RN e Petrolina, PE classificados como de clima Muito Árido. A cultura do coco anão seria a mais penalizada economicamente pela cobrança da água, em virtude do menor custo de manutenção com relação às outras duas culturas da análise. Os valores obtidos através deste estudo poderão ser utilizados como parâmetros de planejamento agrícola irrigado, com maior confiabilidade, quando as médias obtidas, forem agrupadas por clima e os coeficientes de variação apresentarem valores baixos (menor que 10%), desde que tenham características de dimensionamento semelhantes às deste trabalho. E importante observar o comportamento de demanda de irrigação como forma de se avaliar atribuições de tarifa de água bruta, evitando possíveis distorções económicas decorrentes de climas diferenciados em uma mesma bacia hidrográfica / It is considcred, in the present work, an evaluation of costs of energy and water. inside o; the agricultural irrigated planning, getting at first the raw demands from water and energy for the cultures of the dwarfed coconut (Cocos nucifera L.), papaya (Carica papaya) and pacovã banana (Musa spp) in 14 cities from northeast Brazil and if used two pressured systems, through a simulation of agronomic project of irrigation. The lesser foresecn annual water consumption for irrigation was in the locality of Mamanguape, PB, needing itself only 37.4%; 35.5% and 41.4% respectively, for the cultures of dwarfed coconut, papaya and pacovã Banana, based on the consumption gotten in the locality of bigger consumption (Petrolina, PE). Areas with good chance for irrigation had gotten the same using electropumps (7.5 CV and 22 outflow of m3 h"1) for the cultures of dwarfed coconut, papaya and pacovã banana, respectively, of 13.65 ha (located) and 4.54 ha (aspersion); 9,45 ha (located) and 5,18 ha (aspersion) and 6.25 ha (located) and 3.63 ha (Aspersion). The increasing demand of water and energy practically occurred combined by the scale of climatic classification of Hargreaves (1974b), whcre the city of Mamanguape PB (Dry-Wet climate), covered the lesser needs for complementation, following with Pacatuba, SE, Maceió, AE, Aracaju, SE, Natal, RN, Campina Grande, PB, later the cities Acaraú, CE, Aracati, CE and Touros, RN of Semi-Arid climate, Canindé do São Francisco, SE, Sousa, PB and Jaguaribe, CE, with Arid climate and Açu, RN and Petrolina, PE classified as of Very Arid climate. The culture of the dwarfed coconut would be punished economically by the water taxes, because of the lesser cost of maintenance related to the others two cultures in analysis. The values gotten through this study could be used as parameters for irrigated agricultural planning, with bigger trustworthiness, when the gotten averagcs, will be grouped by climate and the coefficients of variation will present low values (lesser than 10%), since they have similar sizing characteristics to the ones of this work. It is important to observe the behavior of irrigation demand as a way of evaluating attributions of raw water taxes, avoiding possible economic distortions due to differentiated climates in one same hidrografic basin.
34

Simulação numérica das interações biosfera-atmosfera em área de caatinga: uma análise da expansão agrícola em ambiente semiárido.

MELO, Ewerton Cleudson de Sousa. 14 August 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-14T10:58:52Z No. of bitstreams: 1 EWERTON CLEUDSON DE SOUSA MELO - TESE (PPGMet) 2016.pdf: 4714414 bytes, checksum: 399def91bcd71b3e8a00a6b001dcfd4b (MD5) / Made available in DSpace on 2018-08-14T10:58:52Z (GMT). No. of bitstreams: 1 EWERTON CLEUDSON DE SOUSA MELO - TESE (PPGMet) 2016.pdf: 4714414 bytes, checksum: 399def91bcd71b3e8a00a6b001dcfd4b (MD5) Previous issue date: 2011-06-30 / CNPq / Neste trabalho a versão 6.0 do modelo numérico RAMS (Regional Atmospheric Modeling System) é usada com o objetivo principal de simular a influência da expansão agrícola nas trocas de água e energia em áreas de Caatinga, e quantificar os efeitos das mudanças na cobertura e uso da terra na geração de circulações termicamente induzidas e na atividade convectiva. Os cenários de uso da terra investigados neste estudo foram construídos para representar condições ambientais nativas (sem influências antrópicas), e com alterações decorrentes da construção da represa de Sobradinho, e da expansão de atividades agrícolas e irrigação em região de clima semiárido. O ambiente atmosférico de grande escala é caracterizado pela estrutura dinâmica e termodinâmica típica da área central de um vórtice ciclônico de altos níveis (VCAN). A escolha do período de estudo teve como objetivo garantir condições ambientais com ampla diversidade agrícola em áreas de Caatinga (culturas de sequeiro e agricultura irrigada), e pouca nebulosidade. A evolução temporal da precipitação convectiva acumulada nas simulações da expansão agrícola mostra diferenças marcantes nos efeitos da agricultura de sequeiro e vegetação irrigada. O aumento na taxa da evapotranspiração nas áreas irrigadas eleva consideravelmente o teor de umidade nos baixos níveis da troposfera, reduz a temperatura do ar e diminui a precipitação convectiva. A descontinuidade na umidade e tipo de cobertura vegetal modifica a intensidade e distribuição dos fluxos turbulentos que são importantes na formação dos gradientes de pressão que geram circulações de brisa (brisa lacustre e de vegetação), de forma que o domínio nos transportes verticais de calor e água passa a ser da mesoescala. Verificou-se que as principais forçantes locais na determinação da distribuição espacial dos fluxos turbulentos e da chuva convectiva foram a topografia e a descontinuidade no teor de umidade do solo. Com relação a estabilidade atmosférica percebeu-se a existência de uma relação quase linear entre a Energia Potencial Convectiva Disponível (CAPE) e a temperatura potencial equivalente. / In this work the version 6.0 of the numerical model RAMS (Regional Atmospheric Modeling System) is used with the main objective of simulating the influence of agricultural expansion on the water and energy exchange in Caatinga vegetation areas, and to quantify the effects that changes on soil use and coverage have on the generation of thermally induced circulations and convective activity. The scenarios of soil use investigated are designed to represent native environmental conditions (without anthropogenic influences) and with alterations due to the implementation of the Sobradinho reservoir, and the expansion of agricultural activities and irrigation in a semiarid climate area. The large scale atmospheric ambient is characterized by the dynamic and thermodynamic structure typical of the central area of an upper level cyclonic vortex. The period of study was chosen aiming at environmental conditions with largely diversified agricultural use in Caatinga vegetation areas (agriculture with and without irrigation), and almost cloudless skies. The temporal evolution of the accumulated convective precipitation in the numerical simulations of the agricultural expansion shows large differences in the effects of agriculture with and without irrigation. The irrigated areas higher evapotranspiration rate causes a substantial increase in the moisture content in the lower troposphere, and lower the air temperature and convective precipitation.

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