Resource Library

This review synthesizes insights from 142 studies showing how satellite remote sensing offers a cost-effective way to monitor key water-quality parameters globally, while highlighting major research gaps in non-optically active indicators and small inland water bodies that call for expanded methods and machine-learning integration.

The Global Freshwater Quality Database GEMStat provides scientifically-sound data and information on the state and trend of global inland water quality. As operational part of the GEMS/Water Programme of the United Nations Environment Programme (UNEP), GEMStat is hosted by the GEMS/Water Data Centre (GWDC) within the International Centre for Water Resources and Global Change (ICWRGC) in Koblenz, Germany.