Global Surface Water

Free and open access to national, sub-national, basin and sub-basin aggregated data on water extent.

This site is still under development and is being shown as a "beta preview" to enable early circulation and discussions for gathering feedback from member countries for refinement.

The broader launch with additional features and data will be at the UN Environmental Assembly in Nairobi, March 2019.

[Pop out embed map into full screen tab]


The map provides a visual depiction of water transitions between 1984 and 2015. In order to visualize annual permanent and seasonal water please select a boundary type and then click in a boundary. The boundary types includes national (GAUL level 0), first level of administrative boundaries within countries (GAUL level 1) or basin level information according to the Pfafstetter levels. The GAUL boundaries are used for analytical purposes only and and do not represent any opinion related to political boundaries.

Note that the dark bars in the charts represent observed permanent or seasonal water. The light bars in the charts represent water that may be permanent; however, due to gaps in the observation record the uncertainty has been filled using trends-analysis. If the observation rate is less than 95% then users should consider the results as experimental. The data underlying the charts can be obtained by clicking the 'Display results as a table' button under each chart.

Downloading the data for multiple boundaries without using the above map is possible via the Data Downloads feature. More information on the methodology and definitions can be accessed on the Definitions page.