646 resultados para Aquifer


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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In Brazil, the large quantities of solid waste produced are out of step with public policies, technological developments, and government budgets for the division. In small municipalities, the common lack of technological knowledge and financial conditions for suitable waste disposal has resulted in a large number of illegal dumps. Therefore, small sanitary landfill facilities are working with simplified operations focusing on cost reduction and meeting the economic and technological standards of the city without endangering the environment or public health. Currently, this activity is regulated at a federal level although there is some uncertainty regarding the risk of soil and aquifer contamination as theses facilities do not employ liners. Thus, this work evaluates a small landfill to identify changes in soil and groundwater using geotechnical parameters, monitoring wells, and geophysical tests performed by electrical profiling. It is verified that based on current conditions, no contaminants have migrated via underground water aquifers, and overall no significant changes have occurred in the soil. It is concluded that, despite its simplicity, the method investigated is a viable alternative for the final disposal of municipal solid waste from small cities, especially in developing countries.

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This study focuses on the presence of radon (Rn-222) and volatile organic compounds (VOCs) in soil gases at a gas station located in the city of Rio Claro, Sao Paulo, Brazil, where a fossil fuel leak occurred. The spatial distribution results show a correlation between Rn-222 and VOCs, consistent with the fact that radon gas has a greater chemical affinity with organic phases than with water. This finding demonstrates that the presence of a residual hydrocarbon phase in an aquifer can retain radon, leading to a reduced radon content in the soil gas. The data in this study confirm the results of previous investigations, in which the method used in this study provided a preliminary fingerprint of a contaminated area. Furthermore, the data analysis time is brief, and only simple equipment is required. (C) 2014 Published by Elsevier Ltd.

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The main purpose of this work is to evaluate the chemical composition of the groundwaters from Guarani Aquifer System and Serra Geral Aquifer System in the Rio Pardo basin, located at the southwestern of São Paulo state. To the hydrochemical characterization, physicalchemical analyses from 32 sampled wells were used. These results were plotted in Piper diagrams allowing the classification of groundwater as calcium or calcium-magnesium bicarbonate type and sodium bicarbonate type for both aquifer systems. Distribution of hydrochemical facies over the study area was obtained using Stiff diagrams. The groundwater can be classified, representing in this sequence its hydrochemical evolution. The recognized mechanisms responsible for groundwater evolution are dissolution of minerals magnesium, such as olivine, present in the basalt, dissolution of feldspars and removal of the carbonate cement of the sandstones mineral framework. Ionic exchange may represent an important processes in the groundwater evolution, responsible for the increase in the sodium concentration and decrease of calcium

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Given the importance of preserving the water quality of the Guarani Aquifer, the work done in the hydrographic basin of the rivers Jacaré-Guaçú e Jacaré-Pepira, located in the central-northern São Paulo state, was made to map the hydraulic conductivity from the use of some empirical methods associated with granulometric analysis and in situ testing, specifically with the Guelph permeameter. All results were submitted to a correlation analysis and subsequently mapped using the methodology of minimum curvature, based on numerical techniques Spline. These procedures provide for studies of aquifer vulnerability and assist in decision making in environmental projects and guidelines for urban planning

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This research aimed to evaluate the quality of “Aquifer Guarani’s” waters in the context of the current legislation related to the radioactive aspects, besides correlating the values obtained with chemical data already available, seeking to make an integrated analysis of the data in order to establish possible tendencies with directions of underground flow. The determinations of the total radioactivity beta and alpha were accomplished through the employment of the available infrastructure at the LABIDRO – Laboratory of Isotope and Hydrochemistry of the Petrology and Metallogeny of UNESP’s Institute of Geosciences and Exact Sciences, largely implanted through resources supplied by FAPESP and CNPq. The systems were gauged for the determinations of interest with tracer of known activity. Preliminaries tests were accomplished with high radioactivity samples of water to check the applicability of the methods. It was ended that the waters analyzed possess low radioactivity, as much alpha as total beta, and, therefore, they are appropriate for the human consumption; that there is not lineal relationship between the obtained data and the chemical data already available; and that the direction of the underground flow of the Aquifer doesn't check any tendency to the generated data.

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The Pirambóia Formation is a lithostratigraphic unit of the Paraná Basin, positioned between the Corumbataí (lower) and Botucatu (upper) Formations on the eastern edge of the basin. This unit is focused by many studies due to its great importance as an essential component in the Guarani Aquifer System (SAG) and the petroleum system “Irati-Pirambóia”, as excellent reservoirs. The Pirambóia Formation is historically the subject of several controversies on issues like age, contact relationships with the upper unit and depositional paleoenvironment. Despite these aspects, the Pirambóia Formation is commonly taken to be of Triassic age and is considered a product of wet aeolian systems, with plenty of wet interdunes and subordinate fluvial facies. In this work, by using techniques such as facies analysis, depositional architecture and facies association, facies of this unit were characterized and their depositional paleoenvironment was inferred particularly in Jundu Mining, region of Descalvado in northeastern São Paulo. Techniques such as grain size and petrographic analyses, aimed to characterize this unit as a potential reservoir rock. Five facies were described for the Pirambóia Formation in the studied region: St, Sh, Sm, Sr and Gt facies, generated by sedimentary processes of the bottom load type, mostly under low flow regime (with exception for the Sh facies, which is formed by upper flow regime processes). In addition to that, four facies associations were recognized from the architectural elements, primarily contained within the main channel: complex channel bars, composed by foreset macroforms (FM), sandy bedforms (SB) and gravel bars and bedforms (GB); flood deposits, constituted by laminated sand sheets (LS); deposits of hyperconcentrated flows and eolian deposits. It was interpreted that the Pirambóia Formation in Descalvado (SP) is the record of the sedimentation of braided rivers, with dunes and interdunes deposits...

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The Urucuia Aquifer System represents a strategic water source in western Bahia. Its baseflow is responsible for the flow rate of the main tributaries of São Francisco river left bank in the dry season, including the Rio Grande, its main tributary in Bahia state. This river has a hydrological regime heavily affected by groundwater and is located in a region with conflicts about water resources. The aquifers geology is constituted by neocretacious sandstones of Urucuia Group subdivided in Posse Formation and Serra das Araras Formation. The embasement is formed by neoproterozoic rocks of Bambuí Group. This work focuses on an important tool application, the mathematical model, whose function is represent approximately and suitably the reality so that can assist in different scenarios simulations and make predictions. Many studies developed in this basin provided the conceptual model basis including a full free aquifer, lithological and hydraulical homogeneity in entire basin, null flux at plateau borders and aquifer base. The finite element method is the numerical method used and FEFLOW the computational algorithm. The simulated area was discretized in a single layer with 27.357,6 km² (314.432 elements and 320.452 nodes) totaling a 4.249,89 km³ volume. Were utilized 21 observation wells from CERB to calibrate the model. The terrain topography was obtained by SRTM data and the impermeable base was generated by interpolation of descriptive profiles from wells and electric vertical drilling from previous studies. Works in this area obtained mean recharge rates varying approximately from 20% to 25% of average precipitation, thus the values of model recharge zones varying in this range. Were distributed 4 hydraulic conductivity zones: (K1) west zone with K=6x10-5 m/s; (K2) center-east zone with K=3x10-4 m/s; (K3) far east zone with K=5x10-4 m/s; e (K4) east-north zone with K=1x10-5 m/s. Thereby was incorporated to the final conceptual model...

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Groundwater in the Rio Claro district is predominantly extracted from low productivity wells on the Itararé Aquifer, from depths greater than 150 m. These factors in conjunction with increasing demand for water supply have stimulated many industries to exploit the Rio Claro Aquifer, constituted by Cenozoic sediments of the Rio Claro Formation, where hydraulic properties are poorly known. For this reason, it is necessary to study the possible vulnerable to contamination punctual locations of the aquifer, in order to enable proper management of these groundwater reserves and to allow continuity of supply. Thus, this study aims to assess the vulnerability to groundwater on contamination Rio Claro Aquifer, punctually in Mandu mining site area, located in the District of Ajapi, Rio Claro - SP, the company which operates and sells industrial sand. The risk of groundwater contamination depends on the relationship between the hydrogeological characteristics of the aquifer layer (vulnerability to contamination) and the pollutant load. To evaluate the susceptibility to contamination it was applied the method GOD (FOSTER and HIRATA, 1987; FOSTER et. al., 2002) and, in addition, field and laboratory tests were performed to chacacterize the granulometry of the strata, hydraulic conductivity and some physical indices to make the evaluation more assertive and detailed. Punctual contamination vulnerability found in the aquifer Rio Claro, was moderate, which means that the aquifer is vulnerable to some contaminants, but when continuously discharged or leached. Thus, Mandu mining has a great role on preventing the emission of contaminants in the process of extraction and processing of sand... (Complete abstract click electronic access below)

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The term model refers to any representation of a real system. The use of models in Hydrogeology can be valuable predictive tools for management of groundwater resources. The numeric models of groundwater flow, object of this study, consist on a set of differential equations that describe the water flow in the porous medium. In this context, numeric simulations were made for a sub-basin located at Cara Preta farm – Santa Rita do Passa Quatro – SP. The aquifer at the local is composed by rocks of Pirambóia Formation, which is part of Guarani Aquifer System. It was developed a conceptual model from previous studies in the area, and from that, simulations were made through the software Visual Modflow®. The conceptual model established previously was considered consistent through the results of simulation.

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The growing interest in the use of groundwater resources is directly related to the economic advantages that the groundwater exploitation offers when compared to surface waters. This happens especially in large urban centers, such as the city of Americana / SP, where the rivers are increasingly contaminated by household and industrial waste. Therefore, this study aimed to characterize the Tubarão Aquifer System, in the city of Americana, to identify and evaluate the spatial distribution of different hydrogeochemical facies as well as understand the rock-fluid interaction through the construction of a conceptual hydrogeochemical model. This study was made based on the recognition of the possible chemical reactions that print the chemical characteristics of groundwater in the area. To do the job, there were two water sampling campaigns of all deep wells used by the City of Americana public water supply. From the results of hydrochemical, classification of water was made by Piper and Stiff diagrams as well as geostatistical data using cluster analysis of principal components. Based on information from the profiles obtained from the survey SIAGAS as well as in geological profiles provided by the city of Americana, we sought to detail the subsurface geology of the Subgroup Itararé in the city of Americana. The results obtained allowed the identification of three hydrochemical types in the study area: Bicarbonated calcium-sodium (1), bicarbonate sodium (2) and sodium chloride (3). The waters have bicarbonate alkaline pH to alkaline and can be considered weakly saline, with electrical conductivity values of around 161 mS / cm. Samples classified as sodium bicarbonate average of 174.99 mS / cm. The pH values ranging from 6.74 to 7.99, averaging 7.52. For the group of waters classified as sodium chloride, conductivity average is 164.32 mS / cm and pH values ranging... (Complete abstract click electronic access below)

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The Guaraní aquifer has relevant importance both as a source of water for several urban centres and the development of agriculture and livestock. In recharge areas the aquifer is free and, therefore, subject to contamination of effluents and tailings deposited on soils that cover it. Thus, it becomes crucial not only its protection at all levels, as the knowledge of its degree of natural vulnerability. The present work used geostatistics modeling techniques to study the natural vulnerability of the Guaraní aquifer in the city of Rio Bonito, State of São Paulo, southeastern Brazil, where the Guarani aquifer is exposed. These techniques, extensively used in evaluation studies of mineral deposits and oil tanks, can be adapted to produce a spatial classification or a regionalisation of probabilistic indices of vulnerability. By ordinary kriging method maps of vulnerability classification were obtained. To determine the vulnerability of the aquifer was employed the Aquifer Vulnerability Index (AVI), which requires knowledge of unsaturated zone thickness and permeability. The final product was a map with probabilistic index of vulnerability of the Guaraní aquifer, which presented values between 0 to 0.33 years, framing the area studied in AVI class extremely high vulnerability

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Concerns about the quality of groundwater have been continuously rising, considering its importance for the public water supply in the State of São Paulo, and even more due to the impact that anthropic action has been causing to the original quality of that natural resource. It is extremely relevant to identify the contamination focuses along the aquifers of the State of São Paulo. This report aims to evaluate nitrates and fluorides concentrations along the aquifers present in the state, in order to identify places where change in the quality of groundwater is observed, through the comparison between measured concentrations and reference values, such as: “Intervention Value” (maximum allowed value) and “Alert Value” (attention required value). To perform this research, a full compilation and organization has been done on chemical analysis data from the “Sistema de Informações de Águas Subterrâneas - SIDAS”, made available by the “Divisão de Procedimentos de Outorga – DPO” of the “Departamento de Água e Energia Elétrica – DAEE”. This work has made possible the build-up of a database composed by 6,860 wells, with analytical data ready to be interpreted, containing information about water pH, electrical conductivity, hardness and chloride, iron, fluoride, nitrogen, nitrates and total dissolved solids concentrations. This database shows concentration data for nitrates (6,157 wells) and fluoride (3,316 wells). From this information, maps for nitrates and fluorides concentration distributions have been made, by each aquifer and each “Unidade de Gerenciamento de Recursos Hídricos – UGRHI”, which has enabled the identification of wells where the concentrations of these chemical compounds exceeds the reference values. Concerning nitrates, these analysis indicated the existence of contamination sources from rural and urban zones, mostly present in the west region... (Complete abstract click electronic access below)