ANNUAL PRECIPITATION TREND AND THE OCCURRENCE OF EXTREME EVENTS IN THE HYDROGRAPHIC BASIN OF RIO PIRAPÓ-PR BETWEEN 1980 TO 2017

Abstract

This research aimed to analyze the distribution pattern and possible trends of average precipitation and maximum rainfall in 24 hours per year in the Pirapó-PR river basin. This basin is located in the Third Planalto Paranaense, between latitudes of 22º 30 ’and 23º 30’ South and longitudes of 51º15 ’and 52º15’ West. To carry out the research, the daily rainfall totals from 1980 to 2017 from 10 rainfall stations of the Instituto das Águas do Paraná - SIH were used. Descriptive statistics was applied to the rainfall data of the 10 pluviometric stations, using the respective parameters: mean, standard deviation and coefficient of variation. Through the Mann-Kendall (1975) non-parametric test, possible trends were verified in the annual series of average annual precipitation and maximum precipitation in 24 hours. The results showed that there is an increase in the distribution of average annual precipitation from the low to the high course of the basin, with the same pattern not being observed for similar daily maximum rainfall. The trend test showed signs of change in the behavior of the annual average values ​​of rainfall and daily maximum, but not significant.