We explored how water flows in small rural streams to improve tools for better managing water resources. Using a new method, we adjusted existing models to consider the size of rainfall events, showing that water movement patterns change depending on the rain’s intensity. This approach makes predictions more accurate and helps scientists and managers understand water availability and protect ecosystems.

Porto Alegre lies within a river junction that has become an important alluvial port as well as a chief industrial and commercial centre. This strategic location resulted in severe damage by flooding. Consequently a complex system of levees and pump stations was implemented during 1960s and 70s. In recent years, the levees were severally criticized by city planners and population due to the false perception of lack of flood risk as since its construction, not a single large flood event occurred.

Results showed an intensification of extreme events in recent years in Northeastern (NE) Brazil , especially in shorter duration rainfall (less than 12 h). Hourly rainfall is bigger in almost all the NE region, but especially in littoral and Northern portion, however, 12 and 24h rainfall exhibit increases in the North, but, lower values in the Southern half of the region in concordance with flood changes reported other authors.

Results show the large potential of a simple general IDF equation as Bell’s (1969) equation to describe and understand the spatial and temporal distribution of extreme hydrological events involving heavy rainfall in Southern Brazil, when associated with TRMM estimate. This is important for a region with data scarcity, especially for shorter durations rainfall