Across the world, countries are building dams to create electricity and boost their economies, but the risks could outweigh the benefits.
Dams often inflicts environmental damage to aquatic eco-systems that creates socio-economic risks to communities dependent on rivers and lakes for their livelihoods. The problem is especially urgent in Southeast Asia, where dams are constructed in the Mekong River for hydropower.
Flowing through Laos, Cambodia, Thailand, Myanmar, Vietnam and China, the Mekong is the world's 10th-largest river and the world's largest inland fishery. It is home to biodiversity that's second only to the Amazon River and boasts immense economic value. It accounts for 25 percent of the global freshwater catch and some 60 million people make an income off the fish as well as crops grown along the river banks.
But hydropower dams on the river are hurting fish stocks and eroding soil fertility, potentially jeopardizing the Mekong's future as a life-sustaining ecosystem. Around 11 mainstream dams and more than a hundred tributary dams are planned by 2040 as regional governments tap their hydropower capacity amid soaring power demand.
Laos has obtained billions from hydropower investors and wants to export the electricity generated by dams to its neighbors in a quest to become the "battery of Asia." The landlocked nation exported electricity worth about $975 million in the first nine months of 2017, according to the International Hydropower Association.
Southeast Asia's electricity shortage makes hydropower an attractive, clean energy source and a valuable source of revenue. Seen as a long-term solution to poverty in rural areas, hydropower also provides water for consumption, storage, irrigation and flood control.
Environmentalists, however, believe hydropower may be doing more harm than good.