Monitoring freshwater ecosystems presents a number of persistent challenges that hinder accurate and consistent reporting on SDG 6.6.1.
- Data fragmentation and inconsistency: Many countries lack national wetland inventories or rely on outdated datasets, leading to fragmented and incomparable information across regions.
- Limited spatial and temporal coverage: Traditional in-situ measurements often fail to capture seasonal dynamics or changes in remote areas, leaving significant data gaps for smaller water bodies and wetlands.
- Divergent typologies and classifications: The use of differing definitions and typologies for wetlands (e.g. Ramsar, IUCN, national classifications) complicates the aggregation and comparison of data at regional and global levels.
- Weak institutional coordination: Responsibilities for water-related ecosystems are often split among ministries or agencies, leading to duplication of efforts and missed opportunities for integrated management.
- Limited technical and analytical capacity: Many national institutions face challenges in accessing, processing, and interpreting large EO datasets, which limits the operational use of satellite-based information for decision-making.
How EO can help
Earth Observation provides a comprehensive, repeatable, and objective means of tracking changes in water-related ecosystems, supporting both national monitoring systems and global assessments.
EO offers consistent and synoptic observations that enable countries to monitor the extent, dynamics, and condition of freshwater bodies over time. Through satellite imagery, it is possible to detect changes in surface water extent, wetland health, and vegetation cover, supporting early warning systems and policy interventions.
The integration of multi-sensor EO data—from optical, radar, and thermal missions—enhances the ability to monitor complex ecosystem processes such as inundation patterns, sedimentation, and vegetation stress. These data are further strengthened when combined with in-situ measurements and hydrological models, providing a more holistic understanding of ecosystem change.
EO also supports harmonisation and interoperability by providing globally consistent datasets that adhere to common standards. This allows countries to align national assessments with international methodologies and ensures comparability for SDG 6.6.1 reporting.
Moreover, EO contributes to capacity building and accessibility. The availability of open-source data platforms, cloud-based processing environments, and interactive visualisation tools allows practitioners, policymakers, and researchers to use EO insights without requiring extensive technical infrastructure.
Finally, linking EO-derived environmental information with socioeconomic and policy data enhances its relevance for decision-making. Such integration supports the development of targeted conservation measures, sustainable land–water management practices, and ecosystem restoration initiatives.
Key examples
1.Freshwater Ecosystem Explorer (UNEP)
The UNEP Freshwater Ecosystem Explorer (SDG661.app) provides countries with near-real-time EO data to monitor changes in the extent and condition of freshwater ecosystems. Built using datasets from JRC, NASA, and Copernicus, it supports national validation and reporting for SDG 6.6.1 every three years.
2.Global Surface Water Explorer (JRC)
Developed by the European Commission’s Joint Research Centre, this platform uses Landsat and Sentinel data to map surface water dynamics globally from 1984 to the present. It allows users to analyse long-term trends in water extent, seasonal variability, and transitions between permanent and temporary water bodies
3. GEO Wetlands Initiative
Under the Group on Earth Observations (GEO) framework, GEO Wetlands promotes the coordinated use of EO for wetland inventory, assessment, and management. It facilitates the exchange of methodologies and data among international organisations, supporting Ramsar Contracting Parties and national authorities in monitoring wetland changes.
4. Global Wetland Watch
This initiative develops global and regional wetland maps using machine learning and Google Earth Engine, producing 10-metre resolution data on wetland extent and type. The project enhances the accuracy of wetland mapping and contributes to the validation of SDG 6.6.1 sub-indicators.
5. Copernicus Water and Wetlands Services
Through Copernicus Land Monitoring Services, Europe provides harmonised data on lakes, rivers, and wetlands, supporting both EU Water Framework Directive assessments and SDG reporting. National agencies, such as those in Finland, are integrating Copernicus datasets with local in-situ measurements to improve the understanding of water ecosystem health.
