The river basins visualization provides rainfall data for the last 35+ years for five of the world’s major rivers (Limpopo, Nile, Orange, Shabelli-Juba, and Zambesi), allowing users to track whether the current basin-wide rainfall is within the normal range, or whether there is a risk of drought and lower river flows or flooding and high river flows.

NB: River basin rainfall that is very high compared to the historical record is not necessarily an indicator of flooding within the basin or downstream from it. Other factors must be taken into consideration to determine whether flooding will occur. However, high rainfall levels can be useful to raise the alarm level or flag a potentially serious situation.

Data sources

Data is provided by CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data), produced by the Climate Hazards Group at the University of California, Santa Barbara.

CHIRPS is a 35+ year quasi-global rainfall dataset. Spanning 50°S-50°N (and all longitudes), starting in 1981 to near-present, CHIRPS incorporates 0.05° resolution satellite imagery with in-situ station data to create gridded rainfall time series for trend analysis and seasonal drought monitoring. CHIRPS data is available at 5 and 10 day accumulations. CHIRPS is free to use and easily accessible at: http://chg.geog.ucsb.edu/data/chirps/

VAM processes this data in-house by aggregating it over the river basins (and sub-basins) on a 10-day basis and deriving cumulative rainfall curves of basin rainfall. The historical data is also pre-processed and used to define bounds of historical variation against which to compare the current season.