Maximum discharge and probable rainfall at Aiuruoca basin, Minas Gerais State

Abstract

Research on rainfall and annual daily maximum discharge rates is essential to support decisions during the design of hydraulic structures. This study tested the adequacy of probability functions to predict the probable rainfall and discharge rates of the Aiuruoca River Basin in Minas Gerais State in Brazil. This basin is very important as starting point of the Rio Grande Basin that eventually discharges into the Parana River in the southern region of Brazil at the border with Argentina. It was found that the log-normal two parameters probability function provided the best fit to historical monthly rainfall series. For example, in the month of January, there is a 75% probability that 201 mm of rainfall will occur. This is the month with the highest volume of rainfall in the region. On another hand, for flow rate, the best fit was provided by the log-normal distribution with three parameters.

Probable rainfall in Lambari region, Southern Minas Gerais State

“…Also, in that month it is essential to crop developments such as beans, maize, coffee and rice, whereas local farmers plan the planting season to match the crop development stage (plants highest need of water) that month. Pinto et al (2014), predicting the probable rainfall of the Aiuruoca River Basin in Minas Gerais State, presented rainfall values of 201mm in January, at 75% probability of occurrence. The Aiuruoca river basin is located in the Alto Rio Grande Basin in the Mantiqueira Range region, from southeastern Brazil.…”

“…Several probability distribution models have been used to estimate probable rainfall to different locals and occurrence periods. Among all, stands out Normal (ANDRADE JÚNIOR;BASTOS, 1997;ASSIS et al, 1996), Gamma (ANDRADE JÚNIOR;BASTOS, 1997;ASSIS et al, 1996;RIBEIRO;LUNARDI, 1997;RIBEIRO et al, 2007;RIBEIRO, 2010;RIBEIRO et al, 2013) and Log-Normal (JUNQUEIRA JUNIOR et al, 2007;PINTO et al, 2014;RIBEIRO et al, 2007).…”