GRanD dams are aligned to the HydroSHEDS river network, which occasionally deviates from river courses visible on satellite imagery. GRanD dam points are located at the outlet point along the most appropriate course in the HydroSHEDS river network.
We appreciate the expertise of our users. If you find a dam in the wrong place, please let us know using the form on our Contact page.
The reservoirs visible in the Reservoirs data layer are those found in GRanD. GRanD focuses on reservoirs that are larger than 0.1km3. There are reservoirs visible in the basemap that are smaller than this volume. Moreover, while GRanD aims for completeness in its records, there are dams and reservoirs that are missing from the current dataset. Efforts are underway to fill gaps in the dataset. Subscribe to our updates to receive news on our progress.
Overlaps exist between the datasets. For example, large dams mapped by GRanD may also exist in GOOD2, though the GOOD2 dam points are location only and do not carry the attribute data found in GRanD. Dams that were under construction before 2015 may have been captured by FHReD; those that have been completed since may also be reflected as completed and operational in GRanD or GOOD2, though again without attribute data. Our future efforts are focused on harmonizing these three datasets so that researchers can either use them independently or in combination with all overlaps attributed for and easily filtered out. Subscribe to our updates to receive news on our progress.
Occasionally, points will appear in duplicate on this map. This issue is caused by slight differences in map tiles and not a problem with the source data. Duplicate points can often be solved by zooming in and out on the map.
Is there an issue that requires attention? Please use the form on our Contact page to reach this map's administrator.