"Small hydropower projects have the potential to bring electricity to millions of people now living off the grid. But experts warn that planners must carefully consider the cumulative effects of constructing too many small dams in a single watershed.
In recent years, however, a strong push for hydroelectric power development has started to change that. Since Uttarakhand’s rise to statehood in 2000, the expansion of hydropower in the region has mirrored the region’s robust economic growth. Many of the dams that have been built are small hydropower projects that harness the force of a river without trapping large reservoirs of water.
But hydropower’s benefits have come at a cost. In June 2013, early and extraordinarily heavy monsoon rains fell for two days, streaming off Uttarakhand’s mountainsides, overflowing its rivers, and overwhelming scores of new dams. The flooding eventually killed almost 6,000 people, tore up 1,300 roads, took out nearly 150 bridges, and destroyed 25 small hydropower projects. The disaster seemed an act of God, but a government-commissioned said much of the blame lay elsewhere — on the new hydroelectric power infrastructure, which included nearly 100 dams, many of them smaller than 25 megawatts in capacity."