A global water scarcity assessment under Shared Socio-economic Pathways – Part 1: Water use

Abstract

Despite the recognized importance of reservoirs and dams, global datasets describing their characteristics and geographical distribution are largely incomplete. To enable advanced assessments of the role and effects of dams within the global river network and to support strategies for mitigating ecohydrological and socioeconomic costs, we introduce here the spatially explicit and hydrologically linked Global Reservoir and Dam database (GRanD). As of early 2011, GRanD contains information regarding 6862 dams and their associated reservoirs, with a total storage capacity of 6197 km3 million reservoirs larger than 0.01 ha -- with a combined storage capacity of approximately 8070 km3 exist worldwide, increasing Earth's terrestrial surface water area by more than 305000 km2 s--1 ), are affected by a cumulative upstream reservoir capacity that exceeds 2{%} of their annual flow; the impact is highest for large rivers with average flows above 1000 m3s--1, of which 46.7{%} are affected. Finally, a sensitivity analysis suggests that smaller reservoirs have substantial impacts on the spatial extent of flow alterations despite their minor role in total reservoir capacity.