This article proposes an approach for hydrological events monitoring, on a Brazilian national scale. It suggests three working environments for a complex structure where several data categories (hydrological, spatial, inventory, etc.), models (analytical and numerical) and a group of mathematical and statistical analysis tools may be use in an integrated manner. River monitoring in a national scale will inevitably face some challenging aspects such as lack of standardized data in a variety of data bases and the insufficient number of telemetric river gauge data. Moreover, when dealing with the impacts of critical hydrological events, the need of data and the efforts associated to turn them into operational information, escalate rapidly.