CECAV
URI permanente desta comunidadehttps://bdc.icmbio.gov.br/handle/cecav/1
Centro Nacional de Pesquisa e Conservação de Cavernas
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3 resultados
Resultados da Pesquisa
- Geological and hydrogeological review of a semi-arid region with conflicts to water availability (southeastern Brazil)(2021-11) P.Bhering, Apolo; Antunes, I.M.H.R.; A.G.Marques, EduardoGroundwater consumption has become increasingly relevant for urban development. The city of Montes Claros (Minas Gerais, Brazil) is located in the border region of the Brazilian semi-arid polygon and has registered conflicts of water use for decades ago. The study area contains a complex karst system responsible for the heterogeneous permeability of water recharge and groundwater flow. The urban area of Montes Claros is located in the Vieira River watershed and contains different groundwater wells used to agro-industrial and human consumption. Almost groundwater captions have a low specific capacity with a consequent groundwater depletion. On the region, there are significant areas with a negative water balance concerning to water recharge and groundwater exploitation. Groundwater flow has a regional dominant direction of SW-NE, however locally, groundwater flow varies and could be identified some clusters with high hydrological potential. The contrast between hydrogeological features of the outcropping lithotypes added to the geological structures contribute to variations in the potentiometric level and in the productivity of aquifers. The main aim of this study is a reviewer of the regional hydrogeology of the municipality of Montes Claros to evaluate a potential groundwater availability on the urban area and minimize a groundwater overexploitation and scarcity. A detailed characterization of the local hydrogeology from Montes Claros region will be crucial to a definition of more efficient water supply policies on the management of water resources, particularly in a scenario of climate change and water scarcity in semi-arid areas.
- An approach to map karst groundwater potentiality in an urban area, Sete Lagoas, Brazil(2020-09-28) Magnabosco, Rafael; Galvão, Paulo; de Carvalho, Ana MacielDue to complex hydrogeological contexts, mapping groundwater potential zones in karst regions is a difficult task. This study was conducted on a karst terrain in Sete Lagoas, Brazil, where rapid urban growth without adequate water resources management resulted in the drilling of unproductive wells and possible aquifer over-exploitation due to the concentration of wells. The objective was to develop a method for mapping groundwater potentiality for karst aquifers, serving as water resources management tool, based on 3D geological modelling, field work and pumping test data, remote sensing, geophysics analysis and production of thematic maps, resulting in the hydrogeological conceptual model. The groundwater potentiality map showed that most potential zones are on the central area, limited by grabens, where limestones are in contact with unconsolidated sediments, on areas with higher density of morphostructural and geophysical lineaments, mainly in east–west and north–east directions, near karst surface features, on thicker karstified zones, with higher recharge rates.
- Natural background levels and validation of the assessment of intrinsic vulnerability to the contamination in the Carste Lagoa Santa Protection Unit, Minas Gerais, Brazil(2019-12-21) Aragão, Frederico; Nunes Menegasse Velásquez, Leila; Galvão, Paulo; de Castro Tayer, Thiaggo; Nogueira Lucon, Thiago; Ruchkys de Azevedo, ÚrsulaThe contamination of karst aquifers by anthropogenic activities causes a major issue regarding environmental policies, since they present high sensitivity, influenced by unique features such as dolines, swallow holes, and conduits. This paper is focused on the Carste Lagoa Santa Protection Unit, MG, Brazil, and presents three main objectives: to determine the natural background levels of chloride, nitrate, sulfate, and phosphate; to indicate the locations where the concentrations of those parameters exceed the natural background levels in the existing vulnerability map and, finally, to determine the proportion of the areas (in percentage) where this surpassing occurs, according to the vulnerability classes (high, moderate and low). Results have shown values (90th percentile) of 2.4 mg/L, 1.0 mg/L, 5.3 mg/L, and 0.1 mg/L, for Cl−, NO3−, SO4−2, and PO4−3, respectively, indicating that for all four parameters, there were areas (mainly distributed within moderate vulnerability portions) where the values were surpassed, which suggests anthropogenic activity due to the presence of urban settlements and agricultural activities. Therefore, the proposal of natural background levels was essential to understand the hydrochemistry of the studied region.