Análise fluviológica e ambiental da bacia hidrográfica do rio Jaú - SP

Abstract

The fluviological analysis is an important tool for planning and managing watersheds once that, by means of the characterization of discharges regime and the pulse of a water curse, it helps to indicate their hydrological state and the contributes to handle the natural resources with focus on ecosystemic services. Using secondary data and knowledge of statistics hydrology, as well computational tools, this study assessed and compared the main discharge variables and the pulse of the rivers situated in the Tietê - Jacaré Water Resources Management Unit. In spite of similar climatic conditions of the basins, the indicators have shown that there is grayer instability of the pulse of River Jaú when compared to the Rivers Jacaré-Pepira; Jacaré-Guaçu and Boa Esperança. The River Jaú has presented the lowest specific minimum discharges and the greatest specific maximum discharges as well as the lowest specific permanence discharges. Also it was the only river to reach, during the study period, the critical drought weather discharge estimates by the Hydrological Regionalization Method for São Paulo State. Furthermore, the fluvial diagram of the River Jaú was most instable and the least predictable, showing a greater number of pulses, the greatest maximum tension and the lowest average amplitude. The environmental analysis has indicated that greater instability of the pulse of the River Jaú is directly related to the poor index of natural vegetal cover and to the high level of risk of the consumption uses of its water. Therefore, based on the method of analysis of multiple criteria with the aid of a Geographic Information System, the present study suggests a proposal of prioritization of areas for Legal Forest within the watershed.