Surface Water Monitoring

Surface Water Monitoring is a satellite-based service from DHI's Earth Observation Centre of Excellence (EOatDHI, formerly DHI GRAS) that identifies water bodies and wetlands and tracks their dynamics, from watershed to national and transboundary basin level. National water authorities, river basin organisations and environmental agencies need this information to assess water availability over time, plan infrastructure such as dams or irrigation schemes, and monitor water-related ecosystems, while disaster management units use it for preparedness, emergency planning and damage assessment.

The deliverables are updated GIS maps with hydrology-related information such as surface water, wetlands, irrigated areas and infrastructure projects in water environments, plus historic and near real time flood mapping. Coverage is worldwide, resolutions go down to 30 cm, and monitoring information can be provided on a weekly basis. Synthetic Aperture Radar (SAR) data allows mapping through clouds and at night. DHI's related work on this solution describes combining Sentinel-1 (radar), Sentinel-2 (optical) and Sentinel-3 (radar altimetry) data to follow both the extent and the water level of reservoirs, as in its analysis of Taiwan's Tsengwen reservoir during the 2021 drought. Data is supplied in a ready-to-use format for existing GIS systems and databases.

DHI led the ESA-funded WorldWater - Surface Water Dynamics project, which produced national inland-water monitoring information for nine pilot countries and regions, including Colombia, Mexico, Gabon, Zambia and Greenland. Published prices start from EUR 0.1 per km2.