A newly launched online database illustrates the impacts of nearly 6,000 dams on the world’s 50 major river basins, ranking their ecological health according to indicators of river fragmentation, water quality, and biodiversity.
The “State of the World’s Rivers” project was developed by the advocacy organization International Rivers and created using Google Earth. Users can compare the health of individual river basins, see the locations of existing and planned dams, and explore 10 of the most significant river basins in more depth.
For example, as this map of China’s Yangtze basin shows, at least 374 dams already exist in the basin, and at least another 167 are under construction or planned to be built. The ecological health of the region is showing signs of collapse, the database entry says: A 2014 study found that fish species in the Yangtze drastically decreased from 143 to 17 over the course of one year, due to overfishing and dam construction.
The 6,000 dams represented in the database are a small percentage of the more than 50,000 large dams that impact the world’s rivers, the organization notes.