【摘 要】
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Semi-arid and arid areas exhibit great temporal variability in water availability. In some of these regions, a one- or two-day rainfall is followed by interveni
【机 构】
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Federal University of Ouro Prato, Geology Department, Carnpos Morro do Cruzeiro, 35400-000 Ouro Pret
论文部分内容阅读
Semi-arid and arid areas exhibit great temporal variability in water availability. In some of these regions, a one- or two-day rainfall is followed by intervening dry periods of variable length. In recent decades, many rivers of the semi-arid portion of the Jequitinhonha Basin have been undergoing a progressive discharge reduction, mainly of their base flow, the are presented herein. Satellite images, hydrometeorological and river discharge data were analyzed; mean and variance tests were conducted to determine temporal homogeneity.Historical pluviometric data analysis shows no corresponding precipitation reduction and temperature undergoes only a slight increase in the same period. On the other hand,evaporation is extremely high, higher than precipitation during most of the year, leaving alwaters of its tributaries are now occupied by a monoculture, Eucaliptus sp., used for paper production. Because of the decreased fluvial discharges, its lowlands, usually used for agriculture and pasture, are abandoned and partially eroded.
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