976 resultados para bacia rifte
Resumo:
Com a análise das características morfométricas procura-se entender a relação solo-superfície, em decorrência dos processos erosivos sobre estruturas e litologias variadas. Neste trabalho, objetivou-se avaliar as características morfométricas do padrão de drenagem e do relevo em microbacias hidrográficas de 2ª ordem de magnitude, em Latossolo Vermelho-Escuro e Argissolo Vermelho-Amarelo, com vistas ao planejamento agroambiental da Bacia Hidrográfica do Córrego Rico, município de Jaboticabal, SP. O estudo foi baseado em fotografias aéreas, pancromáticas, verticais na escala 1:35.000 da região administrativa de Ribeirão Preto. Com técnicas de fotointerpretação, foram traçadas a rede de drenagem e respectivas microbacias hidrográficas, onde as variáveis selecionadas foram determinadas. As classes de risco de degradação, resultando no uso potencial do solo, foram determinadas de acordo com o coeficiente de rugosidade. As características do padrão de drenagem e do relevo repercutiram no comportamento hidrológico e litológico das microbacias hidrográficas, possibilitando a diferenciação entre as unidades de solos. A densidade de drenagem e a amplitude altimétrica foram as características que mais contribuíram para o poder discriminatório na relação solo-superfície. Na análise conjunta do potencial de uso do solo, verificou-se, principalmente, adequação para agricultura nos Latossolos e pecuária e, ou, reflorestamento nos Argissolos.
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The administrative model of the Brazilian State, based on regulation, strives, with the application of the efficiency principle and assessment of economical costs, to give a greater effectiveness to fundamental rights by implementing public policies.The objective of this work is to analyze the role of Oil royalties in the context of the Brazilian State, considering that, being an income gap, they might work as a device that promotes intra/intergenerational justice. By means of a correct and efficient distribution and application in the national region, the royalties constitute financial resources available for implementing public policies that intend to guarantee the fundamental rights; above all, with the discovery of the Pre-salt basin and the indisputable rise in the tax revenues arising from Oil exploration. In the making of this work, the theoretical-descriptive methodology is observed, grounded in a critical-reflexive analysis about Constitutional Law and Oil Law. This work analyzes the administrative model of the Brazilian State, the theory of costs of fundamental rights and the theoretical aspects about royalties, such as: the ethical and economical fundamentals, the distribution and destination of revenues, considering the oil exploration scenario before and after the discovery of the pre-salt basin. it is verified, with the present work, the importance of the creation of a new regulatory framework, and consequently the creation of a sovereign wealth fund, which arises to re-evaluate the application of the current norms of Oil revenue distribution. Still, it is imperative that the mechanisms for controlling the application of royalties are defined in detail, so that those can fully admit the objectives of intra/intergenerational justice. Furthermore, it is emphasized that this process should develop from the efficiency principle viewpoint, as well as the principle of reducing social and regional differences, given that the Oil revenues might be used to ensure fundamental social rights, by implementing public policies that are aligned with the development recommended by the Federal Constitution
Resumo:
O presente estudo trata da avaliação da degradação ambiental da bacia do Rio Uberaba, situada no triângulo mineiro, com área de 241.904,30 ha, abrangendo os municípios de Uberaba, Veríssimo, Conceição das Alagoas e pequena porção de Planura. Neste estudo, foi produzido o mapa de degradação ambiental contendo quatro níveis: baixo, moderado, acentuado e severo. Os parâmetros utilizados nesta avaliação foram: vegetação, topografia, solo/geologia, potencial natural de erosão, mecanização, área agrícola, densidade populacional, pecuarização e área de conflito, aos quais foram atribuídos pesos. Para o nível de degradação “baixo”, foram definidos valores ≤ 13 pontos. Para o nível “moderado”, valores situados no intervalo de 14 a 16. Entre 17 e 19 pontos para o nível “acentuado”, e o nível “severo” com valores ≥ 20 pontos. Este estudo consolida as consequências do uso inadequado das terras, não respeitando a sua aptidão natural. As áreas com nível moderado de degradação representam 47%, áreas de nível acentuado (48%), e severo (4%) representam 52%, o que revela indício muito forte no avanço da destruição dos recursos naturais. As áreas classificadas com nível baixo representam apenas 1%, bastante inexpressiva, destacando o descaso na preservação dos recursos naturais.
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Com o objetivo de verificar a influência de remanescentes de vegetação ciliar e da ação antrópica na qualidade da água, estudaram-se quatro nascentes, sendo duas com a presença de vegetação natural remanescente e duas com predominância de atividades agrícolas. Essas nascentes fazem parte da bacia hidrográfica do Córrego Rico, estando localizadas nos municípios de Taquaritinga e de Guariba - SP, em duas classes de solo: Argissolo e Latossolo, respectivamente. Definiram-se pontos de coleta da água nas nascentes e ao longo dos cursos d'água (entre 0 a 50 m da nascente), em dois períodos (chuvoso e seco). Foram analisadas as seguintes variáveis: cor, pH, temperatura, turbidez, alcalinidade, dureza total, dureza em magnésio, dureza em cálcio, fósforo, nitrogênio e demanda bioquímica de oxigênio. de maneira geral, ocorreu agrupamento por nascentes e também por períodos, confirmando que os períodos de amostragem, assim como as características e diferentes usos do solo influenciam na qualidade da água das microbacias. As variáveis cor, turbidez, alcalinidade e nitrogênio total foram as que apresentaram maior importância relativa nas variáveis canônicas.
Resumo:
A conversão do Cerrado nativo em áreas de exploração agrícola pode modificar os processos de decomposição e síntese da matéria orgânica do solo e, assim, na disponibilidade de nutrientes. Objetivou-se avaliar as propriedades químicas e físicas do solo em topossequência caracterizada por apresentar uso com pastagem cultivada com Brachiaria brizantha ao lado do Cerrado nativo, na camada de 0- 15 cm de profundidade. O estudo foi realizado no município de Colmeia, Estado do Tocantins. Foram determinados 10 pontos de coleta (cinco para Cerrado nativo e cinco para pasto) para cada posição do relevo (topo, encosta e pedimento); em cada ponto amostral, foram coletados solos em três profundidades (0-5, 5-10 e 10- 15 cm), totalizando 90 amostras. Foram realizadas as seguintes análises químicas e físicas: C orgânico, P, K+, Ca2+, Mg2+, H + Al, pH e granulometria. O C orgânico não apresentou diferença (p > 0,05) entre os valores encontrados no Cerrado nativo e pastagem e as posições do relevo avaliadas. A conversão de Cerrado nativo para uso agropecuário reduziu os teores de P. Os teores de K trocável não foram alterados pela retirada da cobertura vegetal original. Observou-se aumento dos teores de areia quando se passou da meia-encosta para o pedimento.
Resumo:
Este trabalho teve por objetivo identificar qualitativamente as áreas suscetíveis à erosão laminar na bacia do Rio Uberaba, localizada em Uberaba -MG, apoiado no modelo matemático da Equação Universal de Perda de Solo (EUPS). Foram utilizadas cartas de: solos, uso e ocupação das terras, redes de drenagem, declividade e dados pluviográficos, utilizando-se de um Sistema de Informação Geográfica (SIG -IDRISI). A espacialização do potencial de erosão só foi possível a partir da estimativa da tolerância às perdas laminares para cada tipo de solo da bacia, e da profundidade dos solos, por entender que as perdas são mais significativas em solos mais rasos do que em solos muito profundos. Na análise dos resultados, verificou-se que 37% da área total da bacia do Rio Uberaba (905,24 km²) sofrem perdas de solos acima do limite de tolerância, sendo 12% em solos profundos e 25% em muito profundos, e a espacialização deste evento favorece a adoção de ações efetivas quanto à conservação dos solos da bacia.
Resumo:
This master´s thesis presents a reliability study conducted among onshore oil fields in the Potiguar Basin (RN/CE) of Petrobras company, Brazil. The main study objective was to build a regression model to predict the risk of failures that impede production wells to function properly using the information of explanatory variables related to wells such as the elevation method, the amount of water produced in the well (BSW), the ratio gas-oil (RGO), the depth of the production bomb, the operational unit of the oil field, among others. The study was based on a retrospective sample of 603 oil columns from all that were functioning between 2000 and 2006. Statistical hypothesis tests under a Weibull regression model fitted to the failure data allowed the selection of some significant predictors in the set considered to explain the first failure time in the wells
Resumo:
Due to the increasing activities and its disordered occupation, the catchment of the Pitimbu river is reason of concern for the population, since the river empties in the lagoon of the Jiqui where 30% of the water of this lagoon are caught for the supplying the city of Natal, playing an important fuction in the supply of water superficial for the capital of the Rio Grande do Norte. The superior stretch of the hydrography catchment of the Pitimbu river - Macaíba/RN, object of this study, is denoted by the eminently agricultural occupation with the use of the irrigated agriculture in the many properties that compose this stretch. Because of this becomes necessary to analyze the availability of the water resources in the catchment of the Pitimbu river, in the superior stretch, collating with the use and occupation of the existing terrain. The stretch in study was divided in eight points which had been performed tests throughout the water and analyzed the parameters physicist-chemistries and heavy metals that are praised by resolution CONAMA nº 357 e, visits in field with photographic survey for characterization of this verifying the situation where if it finds the river. The stretch presented some divergence in the parameters of pH and iron, however the results denote a characteristic of the region. The great amount of slide barrages throughout the river and the wet street was observed, had also verified near the edges the launching of garbage and, the great amount of aquatic vegetation. With this it is concluded that the water of the river can be used for human supplying, therefore inside presents a quality of drinking waters of the standards demanded for resolution CONAMA nº 357, in this way, the stretch in study could be adopted as an Envoiremental Area Protection (APA), to preserve and to guarantee, at least in this stretch, that its condition remains unchanged and continues to supply of permanent form a water of excellent quality
Resumo:
The present research has the purpose of planning the management of the water resources of the Seridó River watershed, in the state of Rio Grande do Norte, Brazil. It has an emphasis on the amount of surface water available in this region, to provide a sustainable water supply. Based on data and information collected from public departments responsible for the management of the water resources of the Rio Grande do Norte state, well as on researches related to water resources , a watershed balance was done, and the results suggested the transposition of the waters from the Piranhas-Açu river watershed taken from the Oiticica and Armando Ribeiro Gonçalves reservoirs, integrated with the construction of 2 hidroelectrical plants and 2 elevation stations, to pump the amount of water needed to the expected demand in some public dams of the region until 2020. So, with the use of the surface water potential that exists in the region, it was demonstrated that, on the contrary of the public policies implemented in the past and in the current by the federal and state realm, it is possible to supply the currently water demands and also the future ones, in a sustainable way, without the need of importing outter water to the respective watershed. Finally, it was proposed the implementation of the Water Resources Plan in the Seridó region WRPS, aiming at providing an auto-sustainable development by significantly diminishing the effects of the dry seasons in that region, by considering the economic, social and environmental sustainability
Resumo:
Eutrophication has been listed as one of the main problems of water pollution on a global level. In the Brazilian semi-arid areas this problem takes even greater proportions due to characteristical water scarcity of the region. It is extremely important to the predictive eutrophication models development and to the reservoirs management in the semi-arid region, studies that promotes understanding of the mechanisms responsible for the expansion and control of algae blooms, essential for improving the water quality of these environments. The present study had as its main aims, evaluate the temporal pattern of trophic state, considering the influence of nutrients (N and P) and the light availability in the water column in the development of phytoplankton biomass, and perform the mathematical modelling of changes in phosphorus and chlorophyll a concentrations in the Cruzeta man-made lake located on Seridó, a typical semi-arid region of Rio Grande do Norte. To this, a fortnightly monitoring was performed in the reservoir in 05 stations over the months of March 2007 to May 2008. Were measured the concentrations of total phosphorus, total organic nitrogen, chlorophyll a, total, fixed and volatile suspended solids, as well as the measure of transparency (Secchi) and the profiles of photosynthetic active radiation (PAR), temperature, pH, dissolved oxygen and electrical conductivity in the water column. Measurements of vertical profiles have shown some periods of chemical and thermal stratification, especially in the rainy season, due to increased water column depth, however, the reservoir can be classified as warm polimitic. During the study period the reservoir was characterized as eutrophic considering the concentrations of phosphorus and most of the time as mesotrophic, based on the concentrations of chlorophyll a, according to the Thornton & Rast (1993) classification. The N:P relations suggest N limitation, conversely, significant linear relationship between the algae biomass and nutrients (N and P) were not observed in our study. However, a relevant event was the negative and significant correlation presented by Kt and chlorophyll a (r ² = 0.83) at the end of the drought of 2007 and the rainy season of 2008, and the algal biomass collapse observed at the end of the drought season (Dec/07). The equation used to simulate the change in the total phosphorus was not satisfactory, being necessary inclusion of parameters able to increase the power of the model prediction. The chlorophyll a simulation presented a good adjustment trend, however there is a need to check the calibrated model parameters and subsequent equation validation
Resumo:
The Pirangi beach is located in the eastern coastline of Rio Grande do Norte state, in the municipality of Parnamirim and Nísia Floresta. In it flow into Pirangi Watershed (PW), whose water receives large amounts of pollutants, mainly domestic and industrial sewage from districts where pass the rivers that consist it, compromising, thus, the bathing water quality of the Pirangi beach. Bearing in mind the importance of water sanitary quality to ensure an environment that no present risk to the bathers s health, this work had as main objective to assess the influence of the PW s waters in the bathing water quality of the Pirangi beaches. To that end, were made collections of water in the beaches and in the rivers with the intention of quantify the fecal contamination indicators thermotolerant coliforms and enterococci, to then classify the conditions of bathing water quality according with the CONAMA Resolution number 274 of 2000. For the purposes greater knowledge about the health conditions of the Beaches Pirangi and about the influence the PW s waters exert on it, was done parallely to the study of the water quality, an investigation of the sand sanitary quality. Furthermore, it was made an evaluation of the PW s Water Quality through Water Quality Index (WQI). Starting from the results obtained in the research present was possible to verify, among other aspects, that the entry of the PW s waters in the Pirangi beaches exerts direct influence in the bathing water quality of the same ones, being the North Pirangi beach (point tracking PA-02) the most influenced. There was noticed also a significant reduction in the conditions of bathing water quality of the beaches in the rainy season. However, the precariousness do sewerage system of the Natal metropolitan region and the absence of a right system of treatment an final disposal of domestic sewage and industrial are the main factors responsi le for deterioration of the PW s Water Quality, and as a consequence, compromising the bathing water quality of the Pirangi beaches
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
In the contemporary world to the deterioration of semi-arid areas of the planet has been the focus of media attention and the scientific community. Brazil has a semiarid, considered the most problematic of the world, either by pressure from physical factors, whether as a result of misguided public policies, has over time been suffering from the consequences of a deterioration that expands over the years. Methodologies, that amidst the problems of semi-arid, come against the deteriorating local, have a good chance to be reapplied in other contexts around the world. This research, based on methodological model for analyzing environmental deterioration, introduced and examined the applicability of the methodology in the semi-arid region of Rio Grande do Norte - Brazil. Although the results provide guidelines for the introduction of underground dams, the application of the methodology was ineffective, given the high rates of forest cover that gave low values for the physical diagnosis conservationist
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Anthropic disturbances in watersheds, such as inappropriate building development, disorderly land occupation and unplanned land use, may strengthen the sediment yield and the inflow into the estuary, leading to siltation, changes in the reach channel conformation, and ecosystem/water quality problems. Faced with such context, this study aims to assess the applicability of SWAT model to estimate, even in a preliminary way, the sediment yield distribution along the Potengi River watershed, as well as its contribution to the estuary. Furthermore, an assessment of its erosion susceptibility was used for comparison. The susceptibility map was developed by overlaying rainfall erosivity, soil erodibility, the slope of the terrain and land cover. In order to overlap these maps, a multi-criteria analysis through AHP method was applied. The SWAT was run using a five year period (1997-2001), considering three different scenarios based on different sorts of human interference: a) agriculture; b) pasture; and c) no interference (background). Results were analyzed in terms of surface runoff, sediment yield and their propagation along each river section, so that it was possible to find that the regions in the extreme west of the watershed and in the downstream portions returned higher values of sediment yield, reaching respectively 2.8 e 5.1 ton/ha.year, whereas central areas, which were less susceptible, returned the lowest values, never more than 0.7 ton/ha.ano. It was also noticed that in the west sub-watersheds, where one can observe the headwaters, sediment yield was naturally forced by high declivity and weak soils. In another hand, results suggest that the eastern part would not contribute to the sediment inflow into the estuary in a significant way, and the larger part of the sediment yield in that place is due to anthropic activities. For the central region, the analysis of sediment propagation indicates deposition predominance in opposition to transport. Thus, it s not expected that isolated rain storms occurring in the upstream river portions would significantly provide the estuary with sediment. Because the model calibration process hasn t been done yet, it becomes essential to emphasize that values presented here as results should not be applied for pratical aims. Even so, this work warns about the risks of a growth in the alteration of natural land cover, mainly in areas closer to the headwaters and in the downstream Potengi River