Processos hidrológicos na Bacia Hidrográfica do Córrego Zerede em Timóteo-MG

• Autor(a) principal: Pinheiro, Joana Angélica Cavalcanti
• Data de Publicação: 2008
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2987
• topic: Infiltração; Qualidade de água; Defluvio; Infiltration; Water quality; Watershed; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::CONSERVACAO DA NATUREZA

The Manaain Farm, a place used for large religious gatherings, is inserted in Corrego Zerede Watershed, which is a sub-watershed of the Rio Piracicaba. The increasing water demand and the changing on soil use that were being observed in the area along with its users interest in sustainable use of natural resources originated the idea of this work: an analysis of hydrological processes of the watershed. Hydrological monitoring of the area, water infiltration analysis in different soil uses and physical-chemical analysis of the water were made. The hydrological monitoring was made from may of 2006 until april of 2008 by a wireless digital rain gauge and a modified atmometer and from may of 2006 until april of 2007 by the set Parshall flume and ITS-2000. Evapotranspiration was the major cause of water loss at the watershed, except on the months of november, december and january (2006/2007). This was probably due to the increasing of relative humidity of the air caused by the high precipitation occurred on those months, causing a decreasing of leaf transpiration. At the final balance it was verified that water loss at the watershed, represented by surface runoff and evapotranspiration, was greater than the gain of water through precipitation by the amount of 247,7 mm. The sampled soil used for the tests with infiltrometer ring and penetrometer were pasture, secondary forest, natural regeneration and eucalyptus plantation. For each sample, there were three test points distant 1 meter from each other. Eucalyptus plantation and secondary forest of the sub-watershed B presented the highest values of infiltration speed and the lowest values of resistance to penetrometer, although the F test was not significant using an level of 5%. For the water quality analysis, during 3 months of 2007, it were collected compounded samples from 5 different location of the river, which were analyzed to establish color, turbidity, pH, suspended solids (TSS), electrical conductivity (EC), chemical oxygen demand, biochemical oxygen demand and microbiological values. EC and TSS values presented statistical difference between means of the analyzed points. The water colected at Point 4 had higher values of EC than the other points, which indicates that the kitchen waste coming from upstream can be influencing the amount of dissolved salts. The statistical difference between Points 1 and 2 must have been influenced of the runoff canal in between them. The sub-watershed A presented lower TSS values than sub-watershed B showing that modifications occured did not influence the increased values of TSS. The others physical-chemical parameters did not present statistical difference between means. The microbiological analysis had negative results for thermotolerant coliforms indicating a water free of contamination. The results showed the all physical-chemical parameters analyzed are within the values established at CONAMA 357 for Class I pattern of sweet water. This leads to the conclusion that this water meets the quality requirements for the desired uses, indicating the good health of the Corrego Zerede Watershed. The hydric balance turned out to be negative, reflecting the need of applying techniques that will provide a greater gain of water at the watershed. As for the infiltration, the forest soil of sub-watershed B and eucalyptus plantation were the most permeable, however, some locations such as the one with the regeneration forest need especial attention.