Power of the River: Introducing the Global Dam Tracker (GDAT)

DESCRIPTION: Dams are a major source of electricity globally, with hydropower generating 16 percent of the world’s total electricity and 71 percent of all renewable electricity in 2016. Many developing countries possess great untapped hydropower potential. Sub-Saharan Africa, for example, is estimated to have tapped less than 8 percent of its hydropower potential. Proponents of dams praise them as a source of low-carbon electricity, estimated to reduce annual emissions by about 2.8 billion tons of carbon dioxide equivalent. Dams also provide wide-ranging benefits in terms of flood control, irrigation, navigation, and job creation. But harnessing the power of the river comes with concentrated costs, from fragmenting the river system and destroying natural habitat to triggering ecological hazards and displacing millions of people. As the world is undergoing an energy system transformation toward renewable sources to combat climate change and meet emission reduction targets outlined in the Paris Agreement, understanding the costs and benefits of dam construction has important policy implications.

In this project, the authors compiled a global geospatial database of dams, the GDAT, to enable rigorous research on the costs and benefits of dam construction. The project was motivated by the absence of a comprehensive, reliable, real-time, easy-to-use database on global dam construction. Such data could allow policymakers to make informed decisions on the use of hydroelectric power in the future, based on systematic evaluations of the costs and benefits of hydroelectric dams along the dimensions of energy access, climate change mitigation, water supply, ecological preservation, and population displacement.

OUTCOMES: Below is a summary of findings:
• Globally, the authors identify 36,222 dams that are spatially concentrated along major river basins in Asia, North America, South America, and Europe.
• Compared to two widely used datasets, AQUASTAT and Global Reservoir and Dam (GRanD), GDAT has not only 144 percent and 419 percent more dam observations, respectively, but also more comprehensive attribute information, such as completion year, geographic location, main purpose, and reservoir and generation capacity.
• Dams are used for a variety of purposes, with considerable heterogeneity across continents. Worldwide, dams are mainly used for irrigation and hydroelectricity, representing 34 percent and 25 percent of the data, respectively.
• There are notable differences in the distribution of dam completion year across continents. While most developed countries in North America, Europe, and Oceania have witnessed a decline in dam construction since the 1970s, developing countries in Africa, Asia, and South America are experiencing a continued increase in the number of dams currently planned or under construction.