Fabiane Kazue Arai

Characterization of water availability in a hydrographic basin

The quantitative knowledge of hydrological parameters (rainfall and flow) and their spatial and temporal variability on the regions or basins should be understood as essential to the efficient planning and management of water resources. Because the Ivinhema Basin, located in the state of Mato Grosso do Sul, Brazil, represents an important inductor on the region agricultural development, characterized as a major producer of grains and meat, it was used to characterize the hydrological study. Knowing the rainfall, flow and drainage area of each of the studied affluent, it was calculated the proportion of contribution of the affluent. To that end, it was proposed the concepts of potential and real contributions, aiming to identify the proportion of contribution of each of the affluent to the formation of the flow in the Ivinhema Basin. The results revealed that: the highest rainfall in the Ivinhema Basin occurred in the headwater regions; the mean specific flow of long duration reduces from the headwater to the mouth of Ivinhema Basin; the Sub-basin of Dorados River has the highest potential and real contribution for the formation of the Ivinhema Basin flow; and the drainage areas of the affluent Dourados and Vacaria contribute with 53% flow of the basin.

Espacialização da precipitação e erosividade na Bacia Hidrográfica do Rio Dourados - MS

The distribution of rainfall in a watershed bay during the year is one of the determining factors to quantify the need for irrigation of crops and domestic and industrial water supply, beyond studies to control flooding and soil erosion. The rain potency to cause erosion can be assessed by indices that are based on physical rainfall characteristics in each region, which erosion is an index. In this study it was analyzed the yearly and monthly indices of rainfall and erosion spacialization in Dourados Watershed Bay. According with the results it was possible to conclude: the rainfall presented a unimodal oscillation, the rainy season ranged from October to March, every month of the rainy season showed a dramatic reductions in the average rainfall, the yearly erosion ranged from 3.192,0 to 4.977,0 MJ mm ha-1 h-1 year-1, and the highest risks of soil loss by water erosion was in the months of December and January.