Caracterização e uso da bacia hidrográfica do córrego Zerede, Timóteo-MG

Abstract

It is common the no–integrated treatment of the studies of the natural phenomena, perhaps presupposing of that knowing some parts of a system it can be known in this whole. However, to conserve the nature, particularly the soil and the water, it is necessary the coordinated and integrated envolvement of everyone, making that the small watershed corresponds the fundamental unit of work in the soil and environment conservation, since it allows the gradual detailing of study without the loss of the group sense. Thus, it was taken as experimental unit the Zerede stream watershed in the city of Timóteo – MG, for being an area that will have as objective the preservation of the natural resources from the rational use, mainly the water, besides taking knowledge about practices of environmental education for the local population. Thus, with the objective of proceeding the environmental characterization from the area and the survey of the current use for a post proposal of modification of the ground occupation, having as an objective of the production of water in quantify and quality, and better conservation of the soil. The area was traveled for a general recognition, observing the landscape aspects, use of soil, among others. Field works, were made, such as collections of water samples, trench openings and collection of ground samples, level altimeter survey of the area, measurement of outflow and precipitation of the watershed; laboratory works, such as physical, chemical and biological analyses of the water, physical and chemical analyses of the soil; and office works, with the generation of maps, determination of physiographic rates of the watershed; besides the obtaining of no conventional aerial photographs. The results obtained through the variables which determine the form of the watershed show that the watershed to a long form, which reduces the probability of receiving a great load of water in a unique point, as a result of a normal rain, and consequently to have a flood. The basin has a strong waved relief with predominancy of areas (96%) with slope above 20%. The rains are concentrated between November and January, which can be more than 70% of the annual precipitation. In the biggest part of the samples, the biological characteristics of the water (thermotoleraled coliforms) satisfy the demanded requisites for class 1, as established by CONAMA. The physical and chemical quality of the water is influenced by the season, where the turbidity variable is the one which most affects the quality of the water in the rainy station and the pH and O2 variables most affect it in the dry period. The soils are in their majority, poor and they present, as the richest part of the ground, the first 20 cm of depth, which probably is related to nutritious recurrent. In general the grounds are very bad weather and are submitted to an intense process of erosion, mainly the linear one.