Analysis of flows in the Guaíba Hydrographic Region: Current variability and Trends due to Climate Change

Abstract

Climate change has become a worldwide theme discussed in the last decades, mainly about the various expected impacts. Some research claims that some of these impacts are already occurring, such as the change in the rainfall regime, causing more frequent droughts and floods, an increase in sea levels, among others. Based on this, monitoring water resources to analyze possible changes in hydrological behavior is fundamental for the proper planning and management of these resources. Therefore, the objective of this research was to evaluate the flow behavior in the Guaíba hydrographic region over a period of 33 years and disturb the series based on expected trends due to climate changes to assess how the flo ws can be affected. For this purpose, data on maximum m onthly flows for the period from 1985 to 2017 were obtained from ten fluviometric stations in the Guaíba hydrographic region, southern Brazil. These data were evaluated using descriptive statistics and permanence curves. Afterwards, the series were disturb ed and evaluated again. Through the observation of the historical behavior of the flow it was noticed that many stations indicate changes in the temporal variation, with a tendency to increase the number of great magnitude flows, but, on the other hand, it is verified the temporal increase of minimum flows. The projected trends for the region indicate an increase in the volume of precipitation and in the flow of the rivers, however they tend to be more concentrated in short periods of time.