Pluviometric variability, water balance and risk of dry spells in the basin of Paraná River III, Brazil

Abstract

For the agriculture context, the water balance and precipitation analysis are essential for planning and decision-making. The objective of this work was to carry out the analyse of pluviometric variability, climatological water balance (CLIMWB) and the occurrence of dry spells in the Basin of Paraná River III, Paraná State, Brazil. For this purpose, 43 meteorological data from 43 stations, from 1976 to 2018, were used. Geoprocessing techniques were applied to regionalize rain data, in addition to box plots and probabilities to analyze precipitation and the occurrence of dry spells. A signficant precipitation variability was identified with regional and temporal discrepancies. Despite the Basin of Paraná River III is a rainy region in the Paraná State, the occurrence of dry spells was identified. Periods of 20 to 30 days with no precipitation event in the region they were also frequent, due the annual occurrence risks ranging from 80 to 50 %, respectively. The risk of 40 consecutive days without rain has already proved to be nil. The water balance exhibited sufficient values for agricultural practice with water surplus along the Basin. However, when analyzing dry years, a water deficit of more than 100 mm in a single month can occur.