Frequently Asked Questions:
Q: What is Sustainable Development Goal indicator 6.6.1?
A: Water bodies are crucial for sustaining life and ecosystem services. As part of the 2030 Agenda for Sustainable Development, UN Member States committed to achieving Sustainable Development Goal (SDG) 6, ensuring water and sanitation for all. Within SDG 6, target 6.6 specifically aims to protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers, and lakes. Monitoring progress on target 6.6 uses one global indicator, indicator 6.6.1, change in the extent of water-related ecosystems over time, which can provide the necessary data for countries to take action. Water-related ecosystems include five categories: vegetated wetlands, rivers and estuaries, lakes, aquifers, and artificial waterbodies. SDG indicator 6.6.1 includes three components: spatial extent of water-related ecosystems and inland open waters, quantity of water in ecosystems, and quality of water in ecosystems (see SDG indicator 6.3.2). So far, only extent of water-related ecosystems is available on this site.
Q: What is the Water-Related Ecosystems site?
A: To make progress on indicator 6.6.1, UN Environment has led the process since 2015 to develop an indicator monitoring methodology. However, the pilot data collection for indicator 6.6.1 conducted by UN Environment in 2017 found that only 20 per cent of United Nations Member States were able to provide the information from a self-reporting questionnaire. To fill the data gap, UN Environment and Google have collaborated with the European Commission’s Joint Research Centre and launched this Water-Related Ecosystems platform, aiming at providing free and open access to national, sub-national, basin and sub-basin aggregated data on water extent. Satellite-based Earth observations on this site partially supplement countries’ in situ monitoring and nationally reported data. Currently the site covers only parts of indicator 6.6.1 components (i.e. change in spatial extent of open water bodies) but will include others (e.g. water quantity and quality, natural and artificial water bodies, etc.) in the future.
Q: How can I use this site to report progress on SDG target 6.6?
A: The components of SDG indicator 6.6.1 that are currently covered by the site (i.e. change in spatial extent of open water bodies) will be shared with countries before being submitted to the UN SDGs database, maintained by the UN Statistics Division. This will need to be augmented by countries’ in situ monitoring and nationally reported data. In the future there are plans to include more information (e.g. water quantity and quality, natural and artificial water bodies, etc.) to help countries in their reporting of SDG target 6.6.
Q: What kind of data can I access and what is the data source?
A: Various formats of data can be accessed including GeoTiff, tabular CSV, and shapefile layers. Data products such as annual averages, five-year average and season averages, annual permanent water and seasonal water have been extracted from the Global Surface Water Explorer (GSWE), developed by the European Commission’s Joint Research Center in partnership with Google Earth. Political boundaries such as FAO Global Administrative Unit Layers (GAUL) is extracted from the GAUL site. Watershed boundaries such as WWF HydroBASINS is extracted from HydroBASINS site.
Earth observation data (i.e., spatial extent of open water bodies) is acquired by Landsat 5, 7 and 8 satellites at a 30 m resolution from 2001-2015. From 2016 to 2030, higher spatial and temporal resolution satellites, including both optical and radar satellites, will be used. For example, 20 m Sentinel 1 (radar) and 10 m Sentinel 2 (optical) satellites, used in combination with Landsat satellites, will allow for a more precise delineation of water bodies both in spatial terms (due to the higher spatial resolution) and in temporal terms (due to the higher revisit time). Learn more about the monitoring methodology by reading the SDG Indicator 6.6.1 Monitoring Methodology document in the Resources page.
Q: How often is the data updated?
A: Satellite data will be updated annually by the first quarter of each year.
Q: What are the next steps for the project?
A: Currently the site covers only parts of indicator 6.6.1 components (i.e. change in spatial extent of open water bodies) but will include others (e.g. water quantity and quality, natural and artificial water bodies, etc.) in the future.
Q: How can I interpret the data from this website?
A: Based on the satellite images accompanied by downloadable statistical data and trend analysis, countries can understand changes occurring in the spatial extent of open water bodies; identify new or lost water bodies, and where changes are happening to seasonal (ephemeral) water bodies. This is valuable for informed decision making on water bodies, and conducive to cross-country collaboration and learning. However, arbitrary conclusions should be avoided such associating a gain of water extent as a positive trend and loss of water extent as a negative trend without further site-specific studies. Data on this site should be used solely as a way to flag potential areas of concern that need to be further researched. Considering unique conditions of each country and complex mechanisms of dynamics of water-related ecosystems, more supportive information are needed to interpret data properly and make decisions comprehensively.
Q: How do I calculate percent change?
A: Using this baseline period, percentage change of spatial extent is calculated using the following formula:
Percentage change in spatial extent = (β - γ )/β*100
Where β = the average national spatial extent from 2001-2005
Where γ = the average national spatial extent of any other 5 year period
Q: Where can I get further help or training?
A: If you cannot find the answer to your questions on this FAQ page, please contact us with further questions and inquiries.