ResumoA crescente demanda de água e as modificações no uso do solo que vêm ocorrendo na bacia hidrográfica do Córrego Zerede ensejaram a realização de análises hidrológicas a fim de um melhor entendimento da dinâmica do ciclo hidrológico local, focando na relação com as florestas e suas consequências para a qualidade da água. Para isso, foi realizado o monitoramento hidrológico através de medições de precipitação, vazão e estimativa de evapotranspiração, utilizando-se um pluviômetro digital sem fio, um atmômetro modificado e pelo conjunto calha Parshall e ITS-2000. Para as análises da qualidade da água, foram coletadas amostras em 5 pontos distintos do curso d'água e analisadas quanto à cor, turbidez, pH, sólidos suspensos totais (SST), condutividade elétrica (CE), demanda química de oxigênio, demanda bioquímica de oxigênio e coliformes termotolerantes. Os resultados mostraram que a evapotranspiração apresentou maior contribuição para saída de água da bacia que o deflúvio, com exceção dos meses de novembro a janeiro (2006/2007). No balanço final, verificou-se o saldo hídrico negativo de 247,7 mm, refletindo precipitações abaixo do esperado para o período e reforçando a importância de utilizar técnicas que permitam uma maior retenção de água na bacia hidrográfica. Os parâmetros CE e SST apresentaram diferenças estatísticas entre as médias dos pontos analisados pelo teste F a 5% de probabilidade, sendo que os demais parâmetros revelaram a inexistência de diferença estatística entre as médias. As análises microbiológicas apresentaram resultados negativos, com a água livre de coliformes termotolerantes. Conclui-se que a água se encontra nos padrões da Classe 1, da Resolução n o 357 do Conama (2005) nos parâmetros analisados, indicando uma boa qualidade na Bacia Hidrográfica do Córrego Zerede. AbstractThe increasing water demand and changes in the land use in the watershed of the Zerede Ceek stimulated hydrological analyses to improve the understanding of the dynamics of the local hydrological cycle, focusing on the relationship with forests and the consequences for the water quality. To this purpose, the hydrological monitoring was carried out by measurements of rainfall, flow rate and estimated evapotranspiration, using a digital wireless rain gauge, a modified atmometer, a Parshall flume set and ITS-2000. For the water quality analysis, samples were collected at five different points of the water course and analyzed for color, turbidity, pH, total suspended solids (TSS), electrical conductivity (EC), chemical oxygen demand, biochemical oxygen demand and heat-tolerant coliforms. The results showed that evapotranspiration contributed more to the amount of water leaving the basin than outflow, except from November to January (2006/2007). The final fluid balance of 247.7 mm was negative, showing that rainfall was lower than expected for the period and reinforcing the importance of using techniques that allow greater water retention in the basin. The parameters EC and TSS differed statistically between the means of the ...

The reduction of forest areas in recent years has influenced landscape fragmentation, compromising ecosystem functions. The natural forest, in addition to maintaining biodiversity, is capable of improving the hydrological conditions of the watershed. This study aimed to characterize the landscape structure of the remaining forest fragments in the São Bartolomeu river basin, at the Zona da Mata of Minas Gerais State, and to assess their physiographic and pedological representativeness. The study area is responsible for most of Viçosa’s water supply, while it is undergoing an urbanization process, reinforcing the need for ordering the use, besides the evaluation of priority areas for conservation. The studies related to the landscape structure were based on the metrics of forest fragments. The representativeness was analyzed regarding the aspects of topographic compartmentation, slope faces, and soils, using the Chi-square test. The natural forest presents fragments varying from medium to large size, with satisfactory proximity between them. However, the forest patches have irregular shapes, favoring the edge effect with a tendency towards irregularity as the fragment size increases. The results of the physiographic and pedological representativeness indicate that the land uses are dependent on the location in the landscape. According to the statistical test, the forest occurs less frequently than expected on the river terraces (48.3%) and convex slopes (2.3%), as well as on the Red-Yellow Acrisols (53.1%), and on the north (28.5%) and west (20.9%) faces. For urban planning and biodiversity conservation purposes, it is recommended to balance the forest area in the different compartments of the landscape, giving priority to the connection of forest fragments.

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