306 resultados para erosão
Resumo:
The scope of this work is the study of natural cavities in gullies through geophysics. The studied area is located in the city of São Pedro (SP) more precisely in the gully of Tucunzinho. The historic of the area shows that, since the 60s there were problems with the high rate of erosion in the gully. In addition to increased erosion, there is the appearance of cavities inside responsible for rebates, aggravating the situation. Geophysical methods have been successfully applied in environmental studies since they are noninvasive, are fast and relatively inexpensive. In order to better understand the context of formation of the pipes in relation to local geology, three arrangements were compared for the method of Electrical Resistivity, Schlumberger, Wenner and Dipole-dipole. Then, it was possible to determine which one is the best for this type of study. According to the data obtained in the field, the Schlumberger array presents more consistent results in relation to the erosive context analyzed
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Interventions in nature made by man are very common since the beginnings of human history, especially in the case regarding the storage of water. The construction of dams have been and still are fundamental in maintaining human life due to the vital importance that water plays. The size of these structures vary according to need, such as water catchment, fish-farming or electricity generation. Embankment dams are the most common type of these structures. Can be defined as dams natural material obtained from loan chambers located near the dam site. This type of barrier may be divided into earth dams and rockfill dams. The study area covers an earth dam located in Cordeirópolis (SP) and is essentially composed of diabases altered soil of the Serra Geral Formation of the Paraná Basin. With the aid of geophysics, more specifically of the Electrical Resistivity method, the aim is to check any water infiltration zones in the dam's body. Given the risks associated with water seepage in earth dams, that may generate breakdown structures, erosion, and consequently accidents and / or harmful factors in the nearby areas. One of the main structural problems married by water infiltration is the possible generation of pipes that could jeopardize the dam structure. This work aims to contribute towards the evaluation of the effectiveness of using an indirect technique of research and monitoring in aid to direct research techniques such as piezometers and drive stakes. The results are presented in the form of 2D and 3D geophysical models, the analysis shows a low resistivity zone with typical values of the presence of humidity originating upstream of the dam and downstream bottleneck trend, that are the basis for interpretation by percolation or not water in the dam
Índices bióticos mono e multimétricos de avaliação da qualidade da água em riachos da Mata Atlântica
Resumo:
Protocols for rapid habitat evaluation and the biotic indices used in biomonitoring of streams in Brazil provide useful information about water quality and modifications in the ecosystem. However, the interpretation of their results is limited. Previous studies pointed out the low sensitivity of those indices to measure the quality of low-order streams, since they only measure organic impacts. Environmental degradation of these streams is mainly related to impacts caused by landscape change, such as erosion, siltation, channel change, loss of riparian vegetation, and reduction in water flow. The streams of the Serra do Japi are under some of these impacts, caused by agricultural activities. In this study, we evaluated whether the reduction of natural characteristics in these environments would decrease water quality. The Protocol of Habitat Diversity was affected by the impacts of agricultural activities. However, the other three biotic indices: Biological Monitoring Working Party Score System, Average Score Per Taxon, and Index of Benthic Community were not as sensitive to those impacts, since they all indicated a high water quality. An adaptation of the attributes and the scoring system is suggested for defining better policies for the conservation of this area.
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The morphometric study in watersheds is a key part to managing watersheds, because from the morphometric indices can determine the risks and potential of each watershed and assess environmental impacts on them generated mainly by human activities. This study aimed to characterize the watershed of the river Verissimo, located in the municipality of Verissimo - MG, analyze morphometric indices and propose how best to use the soil to minimize erosion impacts to resources hídricos.Foi used digital charts 1:100,000 scale and AutoCAD software for the quantification of vector data. The watershed has an area of 146.055 km2 , 55.902 km perimeter. According to the morphometric indices is considered 5th order, highly branched, slightly elongated format of little risk to floods occur, its main channel corresponds to 28.541 kilometers and has undulated, with an average slope of 8.59%. Through the results of morphometric indices and roughness coefficient, shows the potential of watershed land use on pastures for livestock, and soil conservation practices and water to minimize the impacts of erosion and contamination of water resources.
Resumo:
A produção de alimentos e matérias-primas é considerada um dos maiores desafios da atualidade. Assim, os impactos gerados pela atividade da agricultura são muitos, como por exemplo, erosão dos solos, poluição de águas doces e geração de resíduos. Com isso faz-se necessário o desenvolvimento de tecnologias para promover a redução desses impactos. O presente trabalho tem como objetivo apresentar e discutir análises energéticas em sistemas de produção agrícola como uma ferramenta capaz de destacar a dependência dos agroecossistemas de energia externa e de fontes não renováveis, particularmente de fontes fósseis. Assim, com o uso dessa ferramenta, alternativas para uma produção agrícola com menos impacto ambiental pode ser alcançada, proporcionando a ampliação das possibilidades para uma produção mais sustentável.
Resumo:
The city of Lençóis Paulista has a great part of its agricultural land cultivated by sugar cane and reforestation of eucalyptus and pine trees. In the county there are industries that exploit energy extracted from energy cogeneration. The city of Lençóis Paulista, in recent years, has been demonstrating considerable levels of economic and social growth with the industries that are working with sugarcane and eucalyptus mainly responsible. However, the expansion of agricultural land in many cases does not take into consideration the permanent preservation areas that are protected by the law. The APP's are of fundamental importance in the management and conservation of the environment preserving the natural plants and wildlife, and also preventing erosion and the silting of drainage networks. This objective of this study was to diagnose land use, analyze if Permanent Preservation Areas are regulated to the Brazilian Forestry Code (1965) and also diagnose areas of conflict. In relation to the use and occupation of land, the research has shown how the land is divided (agricultural crops and urban zones), and highlighted areas of conflict with the Permanent Preservation Areas. All of the information is contained in maps using Geographic Information Systems. However, it has become clear that environmental laws are not respected as much in urban areas as they are in rural areas. The PPA's are virtually nonexistent, thus creating damage to the environment and local population.
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A análise morfométrica de uma microbacia é uma importante ferramenta de diagnóstico da susceptibilidade à degradação ambiental, pois os resultados nortearão o planejamento, o manejo e a implementação de medidas mitigadoras para conservação dos recursos hídricos. O presente trabalho teve como objetivo a caracterização morfométrica da microbacia do Ribeirão Tabuleta – Piquete (SP) através do Sistema de Informações Geográficas Arcview e da Carta Planialtimétrica de Lorena – SP e Delfim Moreira - MG, editadas pelo IBGE (1970), em escala 1:50000. As variáveis avaliadas foram as dimensionais, da composição da rede de Drenagem e do padrão de drenagem. As bases cartográficas utilizadas foram a carta planialtimétrica de Lorena – SP e Delfim Moreira - MG, editadas pelo IBGE (1970), em escala 1:50000, para a hierarquização da rede de drenagem e a análise morfométrica. Os resultados permitiram concluir que a microbacia apresenta altos riscos de susceptibilidade a erosão e degradação ambiental, sendo fundamental a manutenção da cobertura vegetal e as zonas ripárias para conservação dos serviços ambientais. O fator de forma e a densidade de drenagem alta permitiram inferir que o substrato tem permeabilidade baixa com menor infiltração e maior escoamento da água. A alta declividade das encostas (montanhoso) indica se não for conservada pode haver alteração na regulação do sistema hidrológico e consequentemente na produção de água. O Sistema de Informações Geográficas ArcGis 9.3 foi excelente na digitalização e análise dos dados.
Resumo:
A morfometria é uma ferramenta de grande importância como diagnóstico de suscetibilidade a degradação ambiental, delimitação da zona ripária, planejamento e manejo da microbacia. O presente trabalho teve como objetivo a caracterização morfométrica da microbacia do Ribeirão Benfica – Piquete (SP) através do Sistema de Informações Geográficas Arcview e da Carta Planialtimétrica de Lorena – SP e Delfim Moreira - MG, editadas pelo IBGE (1970), em escala 1:50000. As variáveis avaliadas foram as dimensionais, do padrão de drenagem e do relevo. A base cartográfica utilizada foi as cartas planialtimétricas de Lorena – SP e Delfim Moreira - MG, editadas pelo IBGE (1970), em escala 1:50000, para a hierarquização da rede de drenagem e a análise morfométrica. Os resultados permitiram concluir que a microbacia apresenta altos riscos de susceptibilidade a erosão e degradação ambiental, sendo fundamental a manutenção da cobertura vegetal e as zonas ripárias para conservação dos serviços ambientais. O fator de forma e a densidade de drenagem alta permitiram inferir que o substrato tem permeabilidade baixa com menor infiltração e maior escoamento da água. A alta declividade das encostas (montanhoso) indica que se a microbacia não for conservada pode haver alteração na regulação do sistema hidrológico e consequentemente na produção de água. O Sistema de Informações Geográficas ArcGis 9.3 foi excelente na digitalização e análise dos dados.
Resumo:
Esse trabalho objetivou a aplicação de geoprocessamento na caracterização morfométrica da microbacia do Ribeirão Morro Grande – Bofete (SP) através do Sistema de Informação Geográfica – Selva, visando à preservação, racionalização do seu uso e recuperação ambiental. A microbacia apresenta uma área de 4049ha e está localizada entre os paralelos 22o 50' 05" a 22o 54' 26" de latitude S e 48o 22' 29" a 48o 26' 36" de longitude W Gr. A base cartográfica utilizada foi a carta planialtimétrica de Bofete (SP), em escala 1:50.000 (IBGE, 1968) na extração das curvas de nível, da hidrografia e da topografia, em ambiente de Sistema de Informações Geográficas - Idrisi Selva, para determinação dos índices morfométricos. Os resultados mostram que os baixos valores da densidade de drenagem, associados à presença de rochas permeáveis, facilitam a infiltração da água no solo, diminuindo o escoamento superficial e o risco de erosão e da degradação ambiental, bem como o baixo valor do fator de forma amparado pelo índice de circularidade indica que a microbacia tende a ser mais alongada com menor susceptibilidade à ocorrência de enchentes mais acentuadas. O parâmetro ambiental coeficiente de rugosidade permitiu classificar a microbacia para vocação com floresta e reflorestamento.
Resumo:
This study aims to perform the morphometric characterization of the watershed stream Petiço, Botucatu-SP, through techniques of GIS by GIS IDRISI Selva and Charter planialtimetric Botucatu (SF-22-ZB-VI-3) , edited by IBGE (1969), scale 1: 50000 for ranking the drainage network and the morphometric analysis. The variables analyzed were the dimensions, the relief pattern, pattern of the drainage network and the shape variables. The results show that related to how the watershed has an oblong shape with environmental interpretation with low tendency to flooding and erosion. The sinuosity index of 1.22 shows that the channels of the micro tend to be somewhat sinuous, which allows to infer that is permeable soil with good water infiltration. Based on the results of the morphometric variables was found that the watershed is in good condition of conservation, however, presents certain risks of susceptibility to erosion, and environmental degradation in some points, being fundamental to the maintenance of vegetation cover, in view of the roughness coefficient (Rn). Thus, the evaluation of morphometric characteristics in the study watershed constitutes an important tool in conjunction with the use of GIS and Geographic Information Systems makes possible the planning and management of natural resources aimed at their conservation.
Resumo:
The objective of this study was to evaluate geoprocessing to morphometrically characterize the Ribeirão Descalvado micro watershed – Botucatu, SP by the Geographic Information System (GIS) – Selva for preservation, rationalization of its use and environmental restoration. The micro watershed is 2,228.61 ha between the geographic coordinates: 22° 50' 05" to 22° 54' 26" latitude S and 48° 22' 29" to 48° 26' 36" longitude W Gr. The cartographic basis was the planialtimetric chart of Botucatu (SP), 1: 50000 scale (IBGE, 1969), used for extraction of level, hydrography and topography curves to determine morphometric indices. The results showed that low values of drainage density associated with the presence of permeable rocks facilitates ground water infiltration which decreases surface runoff, erosion risks and environmental degradation. The low value of the shape factor supported by the circularity index shows that the micro watershed is more elongated and at lower risk of more pronounced floods. The roughness coefficient environmental parameter classified the micro watershed for forest and reforestation.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The land use conservation planning requires knowledge of the soil characteristics, natural susceptibility to erosion and the soil loss limit. In this context, the objectives of this study were to perform a detailed soil survey of Ribeirão das Perobas watershed, located in Santa Cruz do Rio Pardo, São Paulo State and to determine and map the erodibility and soil loss tolerance of the soil classes found in the survey. The following techniques were used to perform the detailed soil survey: photopedology, field sampling, physical analysis, chemical analysis, and morphological description of the soil samples and profiles. The erodibility was determined by the methods described by Denardin (1990) and Mannigel et al. (2002), and the determination of soil loss tolerance followed the methodology of Mannigel et al. (2002). The results of erodibility determined by the methodology of Denardin (1990) were not discrepant and they did not distinguish soils that are known to have different susceptibility to erosion., w\Whereas, using the methodology of Mannigel et al. (2002), very high or very low erodibility values were observed in soils with extreme contents of sand silt or clay. The most influent variable to the soil loss tolerance results was the correction factor for the textural gradient of clay between soil horizons.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The study aimed mapping of the land use capacity classes for the Rio das Pedras watershed, Itatinga-SP in order to provide another mechanism of environmental planning for the studied area. It was used 1:10,000 topographic letters for the slope map generation which was overlaid with the studied area soil map. It was applied the judgment table criteria method, for generation of land use capacity map of the studied area. It were identified the following results: First, class III with constraints in relation of low fertility and restrictions about erosion risks on high slope areas. Second, class VI with the same characteristics of class III however with the presence of an aggravating factor of sand texture in all horizons, resulting in high risks of erosion events, especially in high slopes areas, and contamination by pollutants due the high soil permeability. Conclusions: It was verified that the more critical regions for land use capacity classes were VIs and mainly VIes class. The last one has more high relief areas and the presence of Neossolo Quartzarenico soil, with a big erosion propensity. The land use capacity map allow making different decisions for each region of the watershed respecting their individual characteristics.