Global REservoir Inventory (GREI)

GREI documents 556,063 reservoirs across six continents of the world, with a total water surface area of 469,497.10 km² and net water storage capacity of 7,563.04 ± 752.65 km³ (excluding human-regulated lakes with a total capacity of 626.80 km3). GREI includes a significant number of small reservoirs (herein classified as <1 km²) that are underreported in existing global reservoir datasets. Specifically, GREI compiles 39 times more small reservoirs than the recently released and widely used GeoDAR v1.1 dataset. Small reservoirs dominate the global distribution in count (95.38%) but contribute only 4.73% to total storage capacity. In contrast, medium-sized (1–10 km2) and large (≥10 km2) reservoirs account for only 3.84% and 0.78% by count but represent 8.62% and 86.65% of the global net capacity, respectively.