Water Occurrence (1984-2020)

Surface water affects many aspects of our world: the exchange of heat, gas and water vapour between the planet's surface and atmosphere. Water is the engine behind the distribution, movement and migration of Earth's plant and animal life and is just as essential for humans. It affects our capacity to grow crops and manage animal grazing lands, to run our industrial processes, to manufacture goods, it influences the movement of disease-vectors, toxins and pollutants, it generates energy directly (hydroelectric) and indirectly (thermoelectric), it is an essential part of our transport network, and forms part of our recreational, cultural and sporting world. The Water Occurrence dataset shows where surface water occurred between 1984 and 2018. Open water is any stretch of water open to the sky, and includes both freshwater and saltwater. The map displays water surfaces greater than 30m2 that are visible from space, including natural (rivers, lakes, coastal margins and wetlands) and artificial water bodies (reservoirs formed by dams, flooded areas such as opencast mines and quarries, flood irrigation areas such as paddy fields, and water bodies created by hydro-engineering projects such as waterway and harbour construction). This product captures both the intra and inter-annual variability and changes. The permanent water surfaces (100% occurrence over 36 years) are represented in blue, and areas where water sometimes occurs are shown in shades of pink to purple (0% < occurrence < 100%). The paler shades are areas where the water occurs less frequently. The map can support better informed water-management decision-making.