These data are the flow gauge time series components of a curated set of historical daily rainfall and streamflow data for a large region spanning the southern Amazonian rainforest and tropical savanna biomes of Brazil.

Data (columns) include: the year, month, and day ("year", "month", "day") of observations; the daily mean volumetric flow rate in cubic m/second ("value"); a site ID ("site"); and the state within which the flow gauge is located ("state"). Missing values are set to -9999. For each unique site, there exists a corresponding flow gauge location record (see "Flow gauge locations for the Brazilian rainforest-savanna transition zone") as well as a drainage basin or catchment boundary (see "Flow basins for the Brazilian rainforest-savanna transition zone"); these are identified by the same site ID numbers.

Flow data were obtained from free, publicly-available historical records from the Brazilian water management agency: Agência Nacional de Águas (ANA).

Additional data package information and contents, including raw data files, documentation of data acquisition and processing, and related programmatic scripts, are available via Figshare: https://doi.org/10.6084/m9.figshare.3100912.v1