Caracterização da disponibilidade hídrica na Bacia Hidrográfica do Ivinhema, MS

Abstract

The Ivinhema’s hydrographic basin, inserted into the Paraná River Basin, is characterized as being a major producer of grains and meat, however, it has not been the subject of research, especially in relation to the study of water resources, which has limited the technical assistance in aspects of making decisions, development projects and recommendations for system management of soil, water and culture. The knowledge of the average, maximum and minimum flow of the hydrographic basin and their temporal and spatial distributions assume an important role in regional planning, especially as regards the minimum flow in sectors like power generation and navigation, as well as sectorial projects supply, artificial settlement, grant of water use, water quality among others. Based on this approach, we proceeded in this work, the characterization of water availability in the Ivinhema’s basin, relevant to data of annual and monthly average rainfall, stream flow average, annual specific flow average, outflow coefficient, annual minimum flow with seven days duration and return period of 10 years (Q7,10) and flows associated with stays of 95% (Q95%) and 90% (Q90%). The results revealed that: the highest rainfall in the basin occur in the head side of the basin; the rainfall regime has unimodal oscillation; and the rainy season is the period between october and march; the mean specific flow of long-term decreases from the nascent to the mouth in the Ivinhema’s basin to the limit with the Ivinhema’s Station; the Subbasin of the Dourados’ river, which represents 28,9% of the drainage in Ivinhema’s basin, presents more real and potential contribution to the formation of the flow of the Ivinhema’s river; Dourados and Vacaria’s river catchment areas that cover 49,5% of the Basin Ivinhema, in relation to the Ivinhema’s station, contribute with 53% of the flow for the period 1976 to 2006; the Sub-basin Vacaria presents the precipitation and specific mean flow below average of the Ivinhema’s basin, represented by Ivinhema’ station; and the spatial distribution of low flows along the hydrographic river of Ivinhema’s basin ensures continuity of flow throughout the hydrographic river system.